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+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2003-2006, Cluster File Systems, Inc, info@clusterfs.com
+ * Written by Alex Tomas <alex@clusterfs.com>
+ */
+
+
+/*
+ * mballoc.c contains the multiblocks allocation routines
+ */
+
+#include "ext4_jbd2.h"
+#include "mballoc.h"
+#include <linux/log2.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/nospec.h>
+#include <linux/backing-dev.h>
+#include <linux/freezer.h>
+#include <trace/events/ext4.h>
+#include <kunit/static_stub.h>
+
+/*
+ * MUSTDO:
+ * - test ext4_ext_search_left() and ext4_ext_search_right()
+ * - search for metadata in few groups
+ *
+ * TODO v4:
+ * - normalization should take into account whether file is still open
+ * - discard preallocations if no free space left (policy?)
+ * - don't normalize tails
+ * - quota
+ * - reservation for superuser
+ *
+ * TODO v3:
+ * - bitmap read-ahead (proposed by Oleg Drokin aka green)
+ * - track min/max extents in each group for better group selection
+ * - mb_mark_used() may allocate chunk right after splitting buddy
+ * - tree of groups sorted by number of free blocks
+ * - error handling
+ */
+
+/*
+ * The allocation request involve request for multiple number of blocks
+ * near to the goal(block) value specified.
+ *
+ * During initialization phase of the allocator we decide to use the
+ * group preallocation or inode preallocation depending on the size of
+ * the file. The size of the file could be the resulting file size we
+ * would have after allocation, or the current file size, which ever
+ * is larger. If the size is less than sbi->s_mb_stream_request we
+ * select to use the group preallocation. The default value of
+ * s_mb_stream_request is 16 blocks. This can also be tuned via
+ * /sys/fs/ext4/<partition>/mb_stream_req. The value is represented in
+ * terms of number of blocks.
+ *
+ * The main motivation for having small file use group preallocation is to
+ * ensure that we have small files closer together on the disk.
+ *
+ * First stage the allocator looks at the inode prealloc list,
+ * ext4_inode_info->i_prealloc_list, which contains list of prealloc
+ * spaces for this particular inode. The inode prealloc space is
+ * represented as:
+ *
+ * pa_lstart -> the logical start block for this prealloc space
+ * pa_pstart -> the physical start block for this prealloc space
+ * pa_len -> length for this prealloc space (in clusters)
+ * pa_free -> free space available in this prealloc space (in clusters)
+ *
+ * The inode preallocation space is used looking at the _logical_ start
+ * block. If only the logical file block falls within the range of prealloc
+ * space we will consume the particular prealloc space. This makes sure that
+ * we have contiguous physical blocks representing the file blocks
+ *
+ * The important thing to be noted in case of inode prealloc space is that
+ * we don't modify the values associated to inode prealloc space except
+ * pa_free.
+ *
+ * If we are not able to find blocks in the inode prealloc space and if we
+ * have the group allocation flag set then we look at the locality group
+ * prealloc space. These are per CPU prealloc list represented as
+ *
+ * ext4_sb_info.s_locality_groups[smp_processor_id()]
+ *
+ * The reason for having a per cpu locality group is to reduce the contention
+ * between CPUs. It is possible to get scheduled at this point.
+ *
+ * The locality group prealloc space is used looking at whether we have
+ * enough free space (pa_free) within the prealloc space.
+ *
+ * If we can't allocate blocks via inode prealloc or/and locality group
+ * prealloc then we look at the buddy cache. The buddy cache is represented
+ * by ext4_sb_info.s_buddy_cache (struct inode) whose file offset gets
+ * mapped to the buddy and bitmap information regarding different
+ * groups. The buddy information is attached to buddy cache inode so that
+ * we can access them through the page cache. The information regarding
+ * each group is loaded via ext4_mb_load_buddy. The information involve
+ * block bitmap and buddy information. The information are stored in the
+ * inode as:
+ *
+ * { page }
+ * [ group 0 bitmap][ group 0 buddy] [group 1][ group 1]...
+ *
+ *
+ * one block each for bitmap and buddy information. So for each group we
+ * take up 2 blocks. A page can contain blocks_per_page (PAGE_SIZE /
+ * blocksize) blocks. So it can have information regarding groups_per_page
+ * which is blocks_per_page/2
+ *
+ * The buddy cache inode is not stored on disk. The inode is thrown
+ * away when the filesystem is unmounted.
+ *
+ * We look for count number of blocks in the buddy cache. If we were able
+ * to locate that many free blocks we return with additional information
+ * regarding rest of the contiguous physical block available
+ *
+ * Before allocating blocks via buddy cache we normalize the request
+ * blocks. This ensure we ask for more blocks that we needed. The extra
+ * blocks that we get after allocation is added to the respective prealloc
+ * list. In case of inode preallocation we follow a list of heuristics
+ * based on file size. This can be found in ext4_mb_normalize_request. If
+ * we are doing a group prealloc we try to normalize the request to
+ * sbi->s_mb_group_prealloc. The default value of s_mb_group_prealloc is
+ * dependent on the cluster size; for non-bigalloc file systems, it is
+ * 512 blocks. This can be tuned via
+ * /sys/fs/ext4/<partition>/mb_group_prealloc. The value is represented in
+ * terms of number of blocks. If we have mounted the file system with -O
+ * stripe=<value> option the group prealloc request is normalized to the
+ * smallest multiple of the stripe value (sbi->s_stripe) which is
+ * greater than the default mb_group_prealloc.
+ *
+ * If "mb_optimize_scan" mount option is set, we maintain in memory group info
+ * structures in two data structures:
+ *
+ * 1) Array of largest free order xarrays (sbi->s_mb_largest_free_orders)
+ *
+ * Locking: Writers use xa_lock, readers use rcu_read_lock.
+ *
+ * This is an array of xarrays where the index in the array represents the
+ * largest free order in the buddy bitmap of the participating group infos of
+ * that xarray. So, there are exactly MB_NUM_ORDERS(sb) (which means total
+ * number of buddy bitmap orders possible) number of xarrays. Group-infos are
+ * placed in appropriate xarrays.
+ *
+ * 2) Average fragment size xarrays (sbi->s_mb_avg_fragment_size)
+ *
+ * Locking: Writers use xa_lock, readers use rcu_read_lock.
+ *
+ * This is an array of xarrays where in the i-th xarray there are groups with
+ * average fragment size >= 2^i and < 2^(i+1). The average fragment size
+ * is computed as ext4_group_info->bb_free / ext4_group_info->bb_fragments.
+ * Note that we don't bother with a special xarray for completely empty
+ * groups so we only have MB_NUM_ORDERS(sb) xarrays. Group-infos are placed
+ * in appropriate xarrays.
+ *
+ * In xarray, the index is the block group number, the value is the block group
+ * information, and a non-empty value indicates the block group is present in
+ * the current xarray.
+ *
+ * When "mb_optimize_scan" mount option is set, mballoc consults the above data
+ * structures to decide the order in which groups are to be traversed for
+ * fulfilling an allocation request.
+ *
+ * At CR_POWER2_ALIGNED , we look for groups which have the largest_free_order
+ * >= the order of the request. We directly look at the largest free order list
+ * in the data structure (1) above where largest_free_order = order of the
+ * request. If that list is empty, we look at remaining list in the increasing
+ * order of largest_free_order. This allows us to perform CR_POWER2_ALIGNED
+ * lookup in O(1) time.
+ *
+ * At CR_GOAL_LEN_FAST, we only consider groups where
+ * average fragment size > request size. So, we lookup a group which has average
+ * fragment size just above or equal to request size using our average fragment
+ * size group lists (data structure 2) in O(1) time.
+ *
+ * At CR_BEST_AVAIL_LEN, we aim to optimize allocations which can't be satisfied
+ * in CR_GOAL_LEN_FAST. The fact that we couldn't find a group in
+ * CR_GOAL_LEN_FAST suggests that there is no BG that has avg
+ * fragment size > goal length. So before falling to the slower
+ * CR_GOAL_LEN_SLOW, in CR_BEST_AVAIL_LEN we proactively trim goal length and
+ * then use the same fragment lists as CR_GOAL_LEN_FAST to find a BG with a big
+ * enough average fragment size. This increases the chances of finding a
+ * suitable block group in O(1) time and results in faster allocation at the
+ * cost of reduced size of allocation.
+ *
+ * If "mb_optimize_scan" mount option is not set, mballoc traverses groups in
+ * linear order which requires O(N) search time for each CR_POWER2_ALIGNED and
+ * CR_GOAL_LEN_FAST phase.
+ *
+ * The regular allocator (using the buddy cache) supports a few tunables.
+ *
+ * /sys/fs/ext4/<partition>/mb_min_to_scan
+ * /sys/fs/ext4/<partition>/mb_max_to_scan
+ * /sys/fs/ext4/<partition>/mb_order2_req
+ * /sys/fs/ext4/<partition>/mb_max_linear_groups
+ *
+ * The regular allocator uses buddy scan only if the request len is power of
+ * 2 blocks and the order of allocation is >= sbi->s_mb_order2_reqs. The
+ * value of s_mb_order2_reqs can be tuned via
+ * /sys/fs/ext4/<partition>/mb_order2_req. If the request len is equal to
+ * stripe size (sbi->s_stripe), we try to search for contiguous block in
+ * stripe size. This should result in better allocation on RAID setups. If
+ * not, we search in the specific group using bitmap for best extents. The
+ * tunable min_to_scan and max_to_scan control the behaviour here.
+ * min_to_scan indicate how long the mballoc __must__ look for a best
+ * extent and max_to_scan indicates how long the mballoc __can__ look for a
+ * best extent in the found extents. Searching for the blocks starts with
+ * the group specified as the goal value in allocation context via
+ * ac_g_ex. Each group is first checked based on the criteria whether it
+ * can be used for allocation. ext4_mb_good_group explains how the groups are
+ * checked.
+ *
+ * When "mb_optimize_scan" is turned on, as mentioned above, the groups may not
+ * get traversed linearly. That may result in subsequent allocations being not
+ * close to each other. And so, the underlying device may get filled up in a
+ * non-linear fashion. While that may not matter on non-rotational devices, for
+ * rotational devices that may result in higher seek times. "mb_max_linear_groups"
+ * tells mballoc how many groups mballoc should search linearly before
+ * performing consulting above data structures for more efficient lookups. For
+ * non rotational devices, this value defaults to 0 and for rotational devices
+ * this is set to MB_DEFAULT_LINEAR_LIMIT.
+ *
+ * Both the prealloc space are getting populated as above. So for the first
+ * request we will hit the buddy cache which will result in this prealloc
+ * space getting filled. The prealloc space is then later used for the
+ * subsequent request.
+ */
+
+/*
+ * mballoc operates on the following data:
+ * - on-disk bitmap
+ * - in-core buddy (actually includes buddy and bitmap)
+ * - preallocation descriptors (PAs)
+ *
+ * there are two types of preallocations:
+ * - inode
+ * assiged to specific inode and can be used for this inode only.
+ * it describes part of inode's space preallocated to specific
+ * physical blocks. any block from that preallocated can be used
+ * independent. the descriptor just tracks number of blocks left
+ * unused. so, before taking some block from descriptor, one must
+ * make sure corresponded logical block isn't allocated yet. this
+ * also means that freeing any block within descriptor's range
+ * must discard all preallocated blocks.
+ * - locality group
+ * assigned to specific locality group which does not translate to
+ * permanent set of inodes: inode can join and leave group. space
+ * from this type of preallocation can be used for any inode. thus
+ * it's consumed from the beginning to the end.
+ *
+ * relation between them can be expressed as:
+ * in-core buddy = on-disk bitmap + preallocation descriptors
+ *
+ * this mean blocks mballoc considers used are:
+ * - allocated blocks (persistent)
+ * - preallocated blocks (non-persistent)
+ *
+ * consistency in mballoc world means that at any time a block is either
+ * free or used in ALL structures. notice: "any time" should not be read
+ * literally -- time is discrete and delimited by locks.
+ *
+ * to keep it simple, we don't use block numbers, instead we count number of
+ * blocks: how many blocks marked used/free in on-disk bitmap, buddy and PA.
+ *
+ * all operations can be expressed as:
+ * - init buddy: buddy = on-disk + PAs
+ * - new PA: buddy += N; PA = N
+ * - use inode PA: on-disk += N; PA -= N
+ * - discard inode PA buddy -= on-disk - PA; PA = 0
+ * - use locality group PA on-disk += N; PA -= N
+ * - discard locality group PA buddy -= PA; PA = 0
+ * note: 'buddy -= on-disk - PA' is used to show that on-disk bitmap
+ * is used in real operation because we can't know actual used
+ * bits from PA, only from on-disk bitmap
+ *
+ * if we follow this strict logic, then all operations above should be atomic.
+ * given some of them can block, we'd have to use something like semaphores
+ * killing performance on high-end SMP hardware. let's try to relax it using
+ * the following knowledge:
+ * 1) if buddy is referenced, it's already initialized
+ * 2) while block is used in buddy and the buddy is referenced,
+ * nobody can re-allocate that block
+ * 3) we work on bitmaps and '+' actually means 'set bits'. if on-disk has
+ * bit set and PA claims same block, it's OK. IOW, one can set bit in
+ * on-disk bitmap if buddy has same bit set or/and PA covers corresponded
+ * block
+ *
+ * so, now we're building a concurrency table:
+ * - init buddy vs.
+ * - new PA
+ * blocks for PA are allocated in the buddy, buddy must be referenced
+ * until PA is linked to allocation group to avoid concurrent buddy init
+ * - use inode PA
+ * we need to make sure that either on-disk bitmap or PA has uptodate data
+ * given (3) we care that PA-=N operation doesn't interfere with init
+ * - discard inode PA
+ * the simplest way would be to have buddy initialized by the discard
+ * - use locality group PA
+ * again PA-=N must be serialized with init
+ * - discard locality group PA
+ * the simplest way would be to have buddy initialized by the discard
+ * - new PA vs.
+ * - use inode PA
+ * i_data_sem serializes them
+ * - discard inode PA
+ * discard process must wait until PA isn't used by another process
+ * - use locality group PA
+ * some mutex should serialize them
+ * - discard locality group PA
+ * discard process must wait until PA isn't used by another process
+ * - use inode PA
+ * - use inode PA
+ * i_data_sem or another mutex should serializes them
+ * - discard inode PA
+ * discard process must wait until PA isn't used by another process
+ * - use locality group PA
+ * nothing wrong here -- they're different PAs covering different blocks
+ * - discard locality group PA
+ * discard process must wait until PA isn't used by another process
+ *
+ * now we're ready to make few consequences:
+ * - PA is referenced and while it is no discard is possible
+ * - PA is referenced until block isn't marked in on-disk bitmap
+ * - PA changes only after on-disk bitmap
+ * - discard must not compete with init. either init is done before
+ * any discard or they're serialized somehow
+ * - buddy init as sum of on-disk bitmap and PAs is done atomically
+ *
+ * a special case when we've used PA to emptiness. no need to modify buddy
+ * in this case, but we should care about concurrent init
+ *
+ */
+
+ /*
+ * Logic in few words:
+ *
+ * - allocation:
+ * load group
+ * find blocks
+ * mark bits in on-disk bitmap
+ * release group
+ *
+ * - use preallocation:
+ * find proper PA (per-inode or group)
+ * load group
+ * mark bits in on-disk bitmap
+ * release group
+ * release PA
+ *
+ * - free:
+ * load group
+ * mark bits in on-disk bitmap
+ * release group
+ *
+ * - discard preallocations in group:
+ * mark PAs deleted
+ * move them onto local list
+ * load on-disk bitmap
+ * load group
+ * remove PA from object (inode or locality group)
+ * mark free blocks in-core
+ *
+ * - discard inode's preallocations:
+ */
+
+/*
+ * Locking rules
+ *
+ * Locks:
+ * - bitlock on a group (group)
+ * - object (inode/locality) (object)
+ * - per-pa lock (pa)
+ * - cr_power2_aligned lists lock (cr_power2_aligned)
+ * - cr_goal_len_fast lists lock (cr_goal_len_fast)
+ *
+ * Paths:
+ * - new pa
+ * object
+ * group
+ *
+ * - find and use pa:
+ * pa
+ *
+ * - release consumed pa:
+ * pa
+ * group
+ * object
+ *
+ * - generate in-core bitmap:
+ * group
+ * pa
+ *
+ * - discard all for given object (inode, locality group):
+ * object
+ * pa
+ * group
+ *
+ * - discard all for given group:
+ * group
+ * pa
+ * group
+ * object
+ *
+ * - allocation path (ext4_mb_regular_allocator)
+ * group
+ * cr_power2_aligned/cr_goal_len_fast
+ */
+static struct kmem_cache *ext4_pspace_cachep;
+static struct kmem_cache *ext4_ac_cachep;
+static struct kmem_cache *ext4_free_data_cachep;
+
+/* We create slab caches for groupinfo data structures based on the
+ * superblock block size. There will be one per mounted filesystem for
+ * each unique s_blocksize_bits */
+#define NR_GRPINFO_CACHES 8
+static struct kmem_cache *ext4_groupinfo_caches[NR_GRPINFO_CACHES];
+
+static const char * const ext4_groupinfo_slab_names[NR_GRPINFO_CACHES] = {
+ "ext4_groupinfo_1k", "ext4_groupinfo_2k", "ext4_groupinfo_4k",
+ "ext4_groupinfo_8k", "ext4_groupinfo_16k", "ext4_groupinfo_32k",
+ "ext4_groupinfo_64k", "ext4_groupinfo_128k"
+};
+
+static void ext4_mb_generate_from_pa(struct super_block *sb, void *bitmap,
+ ext4_group_t group);
+static void ext4_mb_new_preallocation(struct ext4_allocation_context *ac);
+
+static int ext4_mb_scan_group(struct ext4_allocation_context *ac,
+ ext4_group_t group);
+
+static int ext4_try_to_trim_range(struct super_block *sb,
+ struct ext4_buddy *e4b, ext4_grpblk_t start,
+ ext4_grpblk_t max, ext4_grpblk_t minblocks);
+
+/*
+ * The algorithm using this percpu seq counter goes below:
+ * 1. We sample the percpu discard_pa_seq counter before trying for block
+ * allocation in ext4_mb_new_blocks().
+ * 2. We increment this percpu discard_pa_seq counter when we either allocate
+ * or free these blocks i.e. while marking those blocks as used/free in
+ * mb_mark_used()/mb_free_blocks().
+ * 3. We also increment this percpu seq counter when we successfully identify
+ * that the bb_prealloc_list is not empty and hence proceed for discarding
+ * of those PAs inside ext4_mb_discard_group_preallocations().
+ *
+ * Now to make sure that the regular fast path of block allocation is not
+ * affected, as a small optimization we only sample the percpu seq counter
+ * on that cpu. Only when the block allocation fails and when freed blocks
+ * found were 0, that is when we sample percpu seq counter for all cpus using
+ * below function ext4_get_discard_pa_seq_sum(). This happens after making
+ * sure that all the PAs on grp->bb_prealloc_list got freed or if it's empty.
+ */
+static DEFINE_PER_CPU(u64, discard_pa_seq);
+static inline u64 ext4_get_discard_pa_seq_sum(void)
+{
+ int __cpu;
+ u64 __seq = 0;
+
+ for_each_possible_cpu(__cpu)
+ __seq += per_cpu(discard_pa_seq, __cpu);
+ return __seq;
+}
+
+static inline void *mb_correct_addr_and_bit(int *bit, void *addr)
+{
+#if BITS_PER_LONG == 64
+ *bit += ((unsigned long) addr & 7UL) << 3;
+ addr = (void *) ((unsigned long) addr & ~7UL);
+#elif BITS_PER_LONG == 32
+ *bit += ((unsigned long) addr & 3UL) << 3;
+ addr = (void *) ((unsigned long) addr & ~3UL);
+#else
+#error "how many bits you are?!"
+#endif
+ return addr;
+}
+
+static inline int mb_test_bit(int bit, void *addr)
+{
+ /*
+ * ext4_test_bit on architecture like powerpc
+ * needs unsigned long aligned address
+ */
+ addr = mb_correct_addr_and_bit(&bit, addr);
+ return ext4_test_bit(bit, addr);
+}
+
+static inline void mb_set_bit(int bit, void *addr)
+{
+ addr = mb_correct_addr_and_bit(&bit, addr);
+ ext4_set_bit(bit, addr);
+}
+
+static inline void mb_clear_bit(int bit, void *addr)
+{
+ addr = mb_correct_addr_and_bit(&bit, addr);
+ ext4_clear_bit(bit, addr);
+}
+
+static inline int mb_test_and_clear_bit(int bit, void *addr)
+{
+ addr = mb_correct_addr_and_bit(&bit, addr);
+ return ext4_test_and_clear_bit(bit, addr);
+}
+
+static inline int mb_find_next_zero_bit(void *addr, int max, int start)
+{
+ int fix = 0, ret, tmpmax;
+ addr = mb_correct_addr_and_bit(&fix, addr);
+ tmpmax = max + fix;
+ start += fix;
+
+ ret = ext4_find_next_zero_bit(addr, tmpmax, start) - fix;
+ if (ret > max)
+ return max;
+ return ret;
+}
+
+static inline int mb_find_next_bit(void *addr, int max, int start)
+{
+ int fix = 0, ret, tmpmax;
+ addr = mb_correct_addr_and_bit(&fix, addr);
+ tmpmax = max + fix;
+ start += fix;
+
+ ret = ext4_find_next_bit(addr, tmpmax, start) - fix;
+ if (ret > max)
+ return max;
+ return ret;
+}
+
+static void *mb_find_buddy(struct ext4_buddy *e4b, int order, int *max)
+{
+ char *bb;
+
+ BUG_ON(e4b->bd_bitmap == e4b->bd_buddy);
+ BUG_ON(max == NULL);
+
+ if (order > e4b->bd_blkbits + 1) {
+ *max = 0;
+ return NULL;
+ }
+
+ /* at order 0 we see each particular block */
+ if (order == 0) {
+ *max = 1 << (e4b->bd_blkbits + 3);
+ return e4b->bd_bitmap;
+ }
+
+ bb = e4b->bd_buddy + EXT4_SB(e4b->bd_sb)->s_mb_offsets[order];
+ *max = EXT4_SB(e4b->bd_sb)->s_mb_maxs[order];
+
+ return bb;
+}
+
+#ifdef DOUBLE_CHECK
+static void mb_free_blocks_double(struct inode *inode, struct ext4_buddy *e4b,
+ int first, int count)
+{
+ int i;
+ struct super_block *sb = e4b->bd_sb;
+
+ if (unlikely(e4b->bd_info->bb_bitmap == NULL))
+ return;
+ assert_spin_locked(ext4_group_lock_ptr(sb, e4b->bd_group));
+ for (i = 0; i < count; i++) {
+ if (!mb_test_bit(first + i, e4b->bd_info->bb_bitmap)) {
+ ext4_fsblk_t blocknr;
+
+ blocknr = ext4_group_first_block_no(sb, e4b->bd_group);
+ blocknr += EXT4_C2B(EXT4_SB(sb), first + i);
+ ext4_mark_group_bitmap_corrupted(sb, e4b->bd_group,
+ EXT4_GROUP_INFO_BBITMAP_CORRUPT);
+ ext4_grp_locked_error(sb, e4b->bd_group,
+ inode ? inode->i_ino : 0,
+ blocknr,
+ "freeing block already freed "
+ "(bit %u)",
+ first + i);
+ }
+ mb_clear_bit(first + i, e4b->bd_info->bb_bitmap);
+ }
+}
+
+static void mb_mark_used_double(struct ext4_buddy *e4b, int first, int count)
+{
+ int i;
+
+ if (unlikely(e4b->bd_info->bb_bitmap == NULL))
+ return;
+ assert_spin_locked(ext4_group_lock_ptr(e4b->bd_sb, e4b->bd_group));
+ for (i = 0; i < count; i++) {
+ BUG_ON(mb_test_bit(first + i, e4b->bd_info->bb_bitmap));
+ mb_set_bit(first + i, e4b->bd_info->bb_bitmap);
+ }
+}
+
+static void mb_cmp_bitmaps(struct ext4_buddy *e4b, void *bitmap)
+{
+ if (unlikely(e4b->bd_info->bb_bitmap == NULL))
+ return;
+ if (memcmp(e4b->bd_info->bb_bitmap, bitmap, e4b->bd_sb->s_blocksize)) {
+ unsigned char *b1, *b2;
+ int i;
+ b1 = (unsigned char *) e4b->bd_info->bb_bitmap;
+ b2 = (unsigned char *) bitmap;
+ for (i = 0; i < e4b->bd_sb->s_blocksize; i++) {
+ if (b1[i] != b2[i]) {
+ ext4_msg(e4b->bd_sb, KERN_ERR,
+ "corruption in group %u "
+ "at byte %u(%u): %x in copy != %x "
+ "on disk/prealloc",
+ e4b->bd_group, i, i * 8, b1[i], b2[i]);
+ BUG();
+ }
+ }
+ }
+}
+
+static void mb_group_bb_bitmap_alloc(struct super_block *sb,
+ struct ext4_group_info *grp, ext4_group_t group)
+{
+ struct buffer_head *bh;
+
+ grp->bb_bitmap = kmalloc(sb->s_blocksize, GFP_NOFS);
+ if (!grp->bb_bitmap)
+ return;
+
+ bh = ext4_read_block_bitmap(sb, group);
+ if (IS_ERR_OR_NULL(bh)) {
+ kfree(grp->bb_bitmap);
+ grp->bb_bitmap = NULL;
+ return;
+ }
+
+ memcpy(grp->bb_bitmap, bh->b_data, sb->s_blocksize);
+ put_bh(bh);
+}
+
+static void mb_group_bb_bitmap_free(struct ext4_group_info *grp)
+{
+ kfree(grp->bb_bitmap);
+}
+
+#else
+static inline void mb_free_blocks_double(struct inode *inode,
+ struct ext4_buddy *e4b, int first, int count)
+{
+ return;
+}
+static inline void mb_mark_used_double(struct ext4_buddy *e4b,
+ int first, int count)
+{
+ return;
+}
+static inline void mb_cmp_bitmaps(struct ext4_buddy *e4b, void *bitmap)
+{
+ return;
+}
+
+static inline void mb_group_bb_bitmap_alloc(struct super_block *sb,
+ struct ext4_group_info *grp, ext4_group_t group)
+{
+ return;
+}
+
+static inline void mb_group_bb_bitmap_free(struct ext4_group_info *grp)
+{
+ return;
+}
+#endif
+
+#ifdef AGGRESSIVE_CHECK
+
+#define MB_CHECK_ASSERT(assert) \
+do { \
+ if (!(assert)) { \
+ printk(KERN_EMERG \
+ "Assertion failure in %s() at %s:%d: \"%s\"\n", \
+ function, file, line, # assert); \
+ BUG(); \
+ } \
+} while (0)
+
+static void __mb_check_buddy(struct ext4_buddy *e4b, char *file,
+ const char *function, int line)
+{
+ struct super_block *sb = e4b->bd_sb;
+ int order = e4b->bd_blkbits + 1;
+ int max;
+ int max2;
+ int i;
+ int j;
+ int k;
+ int count;
+ struct ext4_group_info *grp;
+ int fragments = 0;
+ int fstart;
+ struct list_head *cur;
+ void *buddy;
+ void *buddy2;
+
+ if (e4b->bd_info->bb_check_counter++ % 10)
+ return;
+
+ while (order > 1) {
+ buddy = mb_find_buddy(e4b, order, &max);
+ MB_CHECK_ASSERT(buddy);
+ buddy2 = mb_find_buddy(e4b, order - 1, &max2);
+ MB_CHECK_ASSERT(buddy2);
+ MB_CHECK_ASSERT(buddy != buddy2);
+ MB_CHECK_ASSERT(max * 2 == max2);
+
+ count = 0;
+ for (i = 0; i < max; i++) {
+
+ if (mb_test_bit(i, buddy)) {
+ /* only single bit in buddy2 may be 0 */
+ if (!mb_test_bit(i << 1, buddy2)) {
+ MB_CHECK_ASSERT(
+ mb_test_bit((i<<1)+1, buddy2));
+ }
+ continue;
+ }
+
+ /* both bits in buddy2 must be 1 */
+ MB_CHECK_ASSERT(mb_test_bit(i << 1, buddy2));
+ MB_CHECK_ASSERT(mb_test_bit((i << 1) + 1, buddy2));
+
+ for (j = 0; j < (1 << order); j++) {
+ k = (i * (1 << order)) + j;
+ MB_CHECK_ASSERT(
+ !mb_test_bit(k, e4b->bd_bitmap));
+ }
+ count++;
+ }
+ MB_CHECK_ASSERT(e4b->bd_info->bb_counters[order] == count);
+ order--;
+ }
+
+ fstart = -1;
+ buddy = mb_find_buddy(e4b, 0, &max);
+ for (i = 0; i < max; i++) {
+ if (!mb_test_bit(i, buddy)) {
+ MB_CHECK_ASSERT(i >= e4b->bd_info->bb_first_free);
+ if (fstart == -1) {
+ fragments++;
+ fstart = i;
+ }
+ continue;
+ }
+ fstart = -1;
+ /* check used bits only */
+ for (j = 0; j < e4b->bd_blkbits + 1; j++) {
+ buddy2 = mb_find_buddy(e4b, j, &max2);
+ k = i >> j;
+ MB_CHECK_ASSERT(k < max2);
+ MB_CHECK_ASSERT(mb_test_bit(k, buddy2));
+ }
+ }
+ MB_CHECK_ASSERT(!EXT4_MB_GRP_NEED_INIT(e4b->bd_info));
+ MB_CHECK_ASSERT(e4b->bd_info->bb_fragments == fragments);
+
+ grp = ext4_get_group_info(sb, e4b->bd_group);
+ if (!grp)
+ return;
+ list_for_each(cur, &grp->bb_prealloc_list) {
+ ext4_group_t groupnr;
+ struct ext4_prealloc_space *pa;
+ pa = list_entry(cur, struct ext4_prealloc_space, pa_group_list);
+ ext4_get_group_no_and_offset(sb, pa->pa_pstart, &groupnr, &k);
+ MB_CHECK_ASSERT(groupnr == e4b->bd_group);
+ for (i = 0; i < pa->pa_len; i++)
+ MB_CHECK_ASSERT(mb_test_bit(k + i, buddy));
+ }
+}
+#undef MB_CHECK_ASSERT
+#define mb_check_buddy(e4b) __mb_check_buddy(e4b, \
+ __FILE__, __func__, __LINE__)
+#else
+#define mb_check_buddy(e4b)
+#endif
+
+/*
+ * Divide blocks started from @first with length @len into
+ * smaller chunks with power of 2 blocks.
+ * Clear the bits in bitmap which the blocks of the chunk(s) covered,
+ * then increase bb_counters[] for corresponded chunk size.
+ */
+static void ext4_mb_mark_free_simple(struct super_block *sb,
+ void *buddy, ext4_grpblk_t first, ext4_grpblk_t len,
+ struct ext4_group_info *grp)
+{
+ struct ext4_sb_info *sbi = EXT4_SB(sb);
+ ext4_grpblk_t min;
+ ext4_grpblk_t max;
+ ext4_grpblk_t chunk;
+ unsigned int border;
+
+ BUG_ON(len > EXT4_CLUSTERS_PER_GROUP(sb));
+
+ border = 2 << sb->s_blocksize_bits;
+
+ while (len > 0) {
+ /* find how many blocks can be covered since this position */
+ max = ffs(first | border) - 1;
+
+ /* find how many blocks of power 2 we need to mark */
+ min = fls(len) - 1;
+
+ if (max < min)
+ min = max;
+ chunk = 1 << min;
+
+ /* mark multiblock chunks only */
+ grp->bb_counters[min]++;
+ if (min > 0)
+ mb_clear_bit(first >> min,
+ buddy + sbi->s_mb_offsets[min]);
+
+ len -= chunk;
+ first += chunk;
+ }
+}
+
+static int mb_avg_fragment_size_order(struct super_block *sb, ext4_grpblk_t len)
+{
+ int order;
+
+ /*
+ * We don't bother with a special lists groups with only 1 block free
+ * extents and for completely empty groups.
+ */
+ order = fls(len) - 2;
+ if (order < 0)
+ return 0;
+ if (order == MB_NUM_ORDERS(sb))
+ order--;
+ if (WARN_ON_ONCE(order > MB_NUM_ORDERS(sb)))
+ order = MB_NUM_ORDERS(sb) - 1;
+ return order;
+}
+
+/* Move group to appropriate avg_fragment_size list */
+static void
+mb_update_avg_fragment_size(struct super_block *sb, struct ext4_group_info *grp)
+{
+ struct ext4_sb_info *sbi = EXT4_SB(sb);
+ int new, old;
+
+ if (!test_opt2(sb, MB_OPTIMIZE_SCAN))
+ return;
+
+ old = grp->bb_avg_fragment_size_order;
+ new = grp->bb_fragments == 0 ? -1 :
+ mb_avg_fragment_size_order(sb, grp->bb_free / grp->bb_fragments);
+ if (new == old)
+ return;
+
+ if (old >= 0)
+ xa_erase(&sbi->s_mb_avg_fragment_size[old], grp->bb_group);
+
+ grp->bb_avg_fragment_size_order = new;
+ if (new >= 0) {
+ /*
+ * Cannot use __GFP_NOFAIL because we hold the group lock.
+ * Although allocation for insertion may fails, it's not fatal
+ * as we have linear traversal to fall back on.
+ */
+ int err = xa_insert(&sbi->s_mb_avg_fragment_size[new],
+ grp->bb_group, grp, GFP_ATOMIC);
+ if (err)
+ mb_debug(sb, "insert group: %u to s_mb_avg_fragment_size[%d] failed, err %d",
+ grp->bb_group, new, err);
+ }
+}
+
+static int ext4_mb_scan_groups_xa_range(struct ext4_allocation_context *ac,
+ struct xarray *xa,
+ ext4_group_t start, ext4_group_t end)
+{
+ struct super_block *sb = ac->ac_sb;
+ struct ext4_sb_info *sbi = EXT4_SB(sb);
+ enum criteria cr = ac->ac_criteria;
+ ext4_group_t ngroups = ext4_get_groups_count(sb);
+ unsigned long group = start;
+ struct ext4_group_info *grp;
+
+ if (WARN_ON_ONCE(end > ngroups || start >= end))
+ return 0;
+
+ xa_for_each_range(xa, group, grp, start, end - 1) {
+ int err;
+
+ if (sbi->s_mb_stats)
+ atomic64_inc(&sbi->s_bal_cX_groups_considered[cr]);
+
+ err = ext4_mb_scan_group(ac, grp->bb_group);
+ if (err || ac->ac_status != AC_STATUS_CONTINUE)
+ return err;
+
+ cond_resched();
+ }
+
+ return 0;
+}
+
+/*
+ * Find a suitable group of given order from the largest free orders xarray.
+ */
+static inline int
+ext4_mb_scan_groups_largest_free_order_range(struct ext4_allocation_context *ac,
+ int order, ext4_group_t start,
+ ext4_group_t end)
+{
+ struct xarray *xa = &EXT4_SB(ac->ac_sb)->s_mb_largest_free_orders[order];
+
+ if (xa_empty(xa))
+ return 0;
+
+ return ext4_mb_scan_groups_xa_range(ac, xa, start, end);
+}
+
+/*
+ * Choose next group by traversing largest_free_order lists. Updates *new_cr if
+ * cr level needs an update.
+ */
+static int ext4_mb_scan_groups_p2_aligned(struct ext4_allocation_context *ac,
+ ext4_group_t group)
+{
+ struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
+ int i;
+ int ret = 0;
+ ext4_group_t start, end;
+
+ start = group;
+ end = ext4_get_groups_count(ac->ac_sb);
+wrap_around:
+ for (i = ac->ac_2order; i < MB_NUM_ORDERS(ac->ac_sb); i++) {
+ ret = ext4_mb_scan_groups_largest_free_order_range(ac, i,
+ start, end);
+ if (ret || ac->ac_status != AC_STATUS_CONTINUE)
+ return ret;
+ }
+ if (start) {
+ end = start;
+ start = 0;
+ goto wrap_around;
+ }
+
+ if (sbi->s_mb_stats)
+ atomic64_inc(&sbi->s_bal_cX_failed[ac->ac_criteria]);
+
+ /* Increment cr and search again if no group is found */
+ ac->ac_criteria = CR_GOAL_LEN_FAST;
+ return ret;
+}
+
+/*
+ * Find a suitable group of given order from the average fragments xarray.
+ */
+static int
+ext4_mb_scan_groups_avg_frag_order_range(struct ext4_allocation_context *ac,
+ int order, ext4_group_t start,
+ ext4_group_t end)
+{
+ struct xarray *xa = &EXT4_SB(ac->ac_sb)->s_mb_avg_fragment_size[order];
+
+ if (xa_empty(xa))
+ return 0;
+
+ return ext4_mb_scan_groups_xa_range(ac, xa, start, end);
+}
+
+/*
+ * Choose next group by traversing average fragment size list of suitable
+ * order. Updates *new_cr if cr level needs an update.
+ */
+static int ext4_mb_scan_groups_goal_fast(struct ext4_allocation_context *ac,
+ ext4_group_t group)
+{
+ struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
+ int i, ret = 0;
+ ext4_group_t start, end;
+
+ start = group;
+ end = ext4_get_groups_count(ac->ac_sb);
+wrap_around:
+ i = mb_avg_fragment_size_order(ac->ac_sb, ac->ac_g_ex.fe_len);
+ for (; i < MB_NUM_ORDERS(ac->ac_sb); i++) {
+ ret = ext4_mb_scan_groups_avg_frag_order_range(ac, i,
+ start, end);
+ if (ret || ac->ac_status != AC_STATUS_CONTINUE)
+ return ret;
+ }
+ if (start) {
+ end = start;
+ start = 0;
+ goto wrap_around;
+ }
+
+ if (sbi->s_mb_stats)
+ atomic64_inc(&sbi->s_bal_cX_failed[ac->ac_criteria]);
+ /*
+ * CR_BEST_AVAIL_LEN works based on the concept that we have
+ * a larger normalized goal len request which can be trimmed to
+ * a smaller goal len such that it can still satisfy original
+ * request len. However, allocation request for non-regular
+ * files never gets normalized.
+ * See function ext4_mb_normalize_request() (EXT4_MB_HINT_DATA).
+ */
+ if (ac->ac_flags & EXT4_MB_HINT_DATA)
+ ac->ac_criteria = CR_BEST_AVAIL_LEN;
+ else
+ ac->ac_criteria = CR_GOAL_LEN_SLOW;
+
+ return ret;
+}
+
+/*
+ * We couldn't find a group in CR_GOAL_LEN_FAST so try to find the highest free fragment
+ * order we have and proactively trim the goal request length to that order to
+ * find a suitable group faster.
+ *
+ * This optimizes allocation speed at the cost of slightly reduced
+ * preallocations. However, we make sure that we don't trim the request too
+ * much and fall to CR_GOAL_LEN_SLOW in that case.
+ */
+static int ext4_mb_scan_groups_best_avail(struct ext4_allocation_context *ac,
+ ext4_group_t group)
+{
+ int ret = 0;
+ struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
+ int i, order, min_order;
+ unsigned long num_stripe_clusters = 0;
+ ext4_group_t start, end;
+
+ /*
+ * mb_avg_fragment_size_order() returns order in a way that makes
+ * retrieving back the length using (1 << order) inaccurate. Hence, use
+ * fls() instead since we need to know the actual length while modifying
+ * goal length.
+ */
+ order = fls(ac->ac_g_ex.fe_len) - 1;
+ if (WARN_ON_ONCE(order - 1 > MB_NUM_ORDERS(ac->ac_sb)))
+ order = MB_NUM_ORDERS(ac->ac_sb);
+ min_order = order - sbi->s_mb_best_avail_max_trim_order;
+ if (min_order < 0)
+ min_order = 0;
+
+ if (sbi->s_stripe > 0) {
+ /*
+ * We are assuming that stripe size is always a multiple of
+ * cluster ratio otherwise __ext4_fill_super exists early.
+ */
+ num_stripe_clusters = EXT4_NUM_B2C(sbi, sbi->s_stripe);
+ if (1 << min_order < num_stripe_clusters)
+ /*
+ * We consider 1 order less because later we round
+ * up the goal len to num_stripe_clusters
+ */
+ min_order = fls(num_stripe_clusters) - 1;
+ }
+
+ if (1 << min_order < ac->ac_o_ex.fe_len)
+ min_order = fls(ac->ac_o_ex.fe_len);
+
+ start = group;
+ end = ext4_get_groups_count(ac->ac_sb);
+wrap_around:
+ for (i = order; i >= min_order; i--) {
+ int frag_order;
+ /*
+ * Scale down goal len to make sure we find something
+ * in the free fragments list. Basically, reduce
+ * preallocations.
+ */
+ ac->ac_g_ex.fe_len = 1 << i;
+
+ if (num_stripe_clusters > 0) {
+ /*
+ * Try to round up the adjusted goal length to
+ * stripe size (in cluster units) multiple for
+ * efficiency.
+ */
+ ac->ac_g_ex.fe_len = roundup(ac->ac_g_ex.fe_len,
+ num_stripe_clusters);
+ }
+
+ frag_order = mb_avg_fragment_size_order(ac->ac_sb,
+ ac->ac_g_ex.fe_len);
+
+ ret = ext4_mb_scan_groups_avg_frag_order_range(ac, frag_order,
+ start, end);
+ if (ret || ac->ac_status != AC_STATUS_CONTINUE)
+ return ret;
+ }
+ if (start) {
+ end = start;
+ start = 0;
+ goto wrap_around;
+ }
+
+ /* Reset goal length to original goal length before falling into CR_GOAL_LEN_SLOW */
+ ac->ac_g_ex.fe_len = ac->ac_orig_goal_len;
+ if (sbi->s_mb_stats)
+ atomic64_inc(&sbi->s_bal_cX_failed[ac->ac_criteria]);
+ ac->ac_criteria = CR_GOAL_LEN_SLOW;
+
+ return ret;
+}
+
+static inline int should_optimize_scan(struct ext4_allocation_context *ac)
+{
+ if (unlikely(!test_opt2(ac->ac_sb, MB_OPTIMIZE_SCAN)))
+ return 0;
+ if (ac->ac_criteria >= CR_GOAL_LEN_SLOW)
+ return 0;
+ if (!ext4_test_inode_flag(ac->ac_inode, EXT4_INODE_EXTENTS))
+ return 0;
+ return 1;
+}
+
+/*
+ * next linear group for allocation.
+ */
+static void next_linear_group(ext4_group_t *group, ext4_group_t ngroups)
+{
+ /*
+ * Artificially restricted ngroups for non-extent
+ * files makes group > ngroups possible on first loop.
+ */
+ *group = *group + 1 >= ngroups ? 0 : *group + 1;
+}
+
+static int ext4_mb_scan_groups_linear(struct ext4_allocation_context *ac,
+ ext4_group_t ngroups, ext4_group_t *start, ext4_group_t count)
+{
+ int ret, i;
+ enum criteria cr = ac->ac_criteria;
+ struct super_block *sb = ac->ac_sb;
+ struct ext4_sb_info *sbi = EXT4_SB(sb);
+ ext4_group_t group = *start;
+
+ for (i = 0; i < count; i++, next_linear_group(&group, ngroups)) {
+ ret = ext4_mb_scan_group(ac, group);
+ if (ret || ac->ac_status != AC_STATUS_CONTINUE)
+ return ret;
+ cond_resched();
+ }
+
+ *start = group;
+ if (count == ngroups)
+ ac->ac_criteria++;
+
+ /* Processed all groups and haven't found blocks */
+ if (sbi->s_mb_stats && i == ngroups)
+ atomic64_inc(&sbi->s_bal_cX_failed[cr]);
+
+ return 0;
+}
+
+static int ext4_mb_scan_groups(struct ext4_allocation_context *ac)
+{
+ int ret = 0;
+ ext4_group_t start;
+ struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
+ ext4_group_t ngroups = ext4_get_groups_count(ac->ac_sb);
+
+ /* non-extent files are limited to low blocks/groups */
+ if (!(ext4_test_inode_flag(ac->ac_inode, EXT4_INODE_EXTENTS)))
+ ngroups = sbi->s_blockfile_groups;
+
+ /* searching for the right group start from the goal value specified */
+ start = ac->ac_g_ex.fe_group;
+ ac->ac_prefetch_grp = start;
+ ac->ac_prefetch_nr = 0;
+
+ if (!should_optimize_scan(ac))
+ return ext4_mb_scan_groups_linear(ac, ngroups, &start, ngroups);
+
+ /*
+ * Optimized scanning can return non adjacent groups which can cause
+ * seek overhead for rotational disks. So try few linear groups before
+ * trying optimized scan.
+ */
+ if (sbi->s_mb_max_linear_groups)
+ ret = ext4_mb_scan_groups_linear(ac, ngroups, &start,
+ sbi->s_mb_max_linear_groups);
+ if (ret || ac->ac_status != AC_STATUS_CONTINUE)
+ return ret;
+
+ switch (ac->ac_criteria) {
+ case CR_POWER2_ALIGNED:
+ return ext4_mb_scan_groups_p2_aligned(ac, start);
+ case CR_GOAL_LEN_FAST:
+ return ext4_mb_scan_groups_goal_fast(ac, start);
+ case CR_BEST_AVAIL_LEN:
+ return ext4_mb_scan_groups_best_avail(ac, start);
+ default:
+ /*
+ * TODO: For CR_GOAL_LEN_SLOW, we can arrange groups in an
+ * rb tree sorted by bb_free. But until that happens, we should
+ * never come here.
+ */
+ WARN_ON(1);
+ }
+
+ return 0;
+}
+
+/*
+ * Cache the order of the largest free extent we have available in this block
+ * group.
+ */
+static void
+mb_set_largest_free_order(struct super_block *sb, struct ext4_group_info *grp)
+{
+ struct ext4_sb_info *sbi = EXT4_SB(sb);
+ int new, old = grp->bb_largest_free_order;
+
+ for (new = MB_NUM_ORDERS(sb) - 1; new >= 0; new--)
+ if (grp->bb_counters[new] > 0)
+ break;
+
+ /* No need to move between order lists? */
+ if (new == old)
+ return;
+
+ if (old >= 0) {
+ struct xarray *xa = &sbi->s_mb_largest_free_orders[old];
+
+ if (!xa_empty(xa) && xa_load(xa, grp->bb_group))
+ xa_erase(xa, grp->bb_group);
+ }
+
+ grp->bb_largest_free_order = new;
+ if (test_opt2(sb, MB_OPTIMIZE_SCAN) && new >= 0 && grp->bb_free) {
+ /*
+ * Cannot use __GFP_NOFAIL because we hold the group lock.
+ * Although allocation for insertion may fails, it's not fatal
+ * as we have linear traversal to fall back on.
+ */
+ int err = xa_insert(&sbi->s_mb_largest_free_orders[new],
+ grp->bb_group, grp, GFP_ATOMIC);
+ if (err)
+ mb_debug(sb, "insert group: %u to s_mb_largest_free_orders[%d] failed, err %d",
+ grp->bb_group, new, err);
+ }
+}
+
+static noinline_for_stack
+void ext4_mb_generate_buddy(struct super_block *sb,
+ void *buddy, void *bitmap, ext4_group_t group,
+ struct ext4_group_info *grp)
+{
+ struct ext4_sb_info *sbi = EXT4_SB(sb);
+ ext4_grpblk_t max = EXT4_CLUSTERS_PER_GROUP(sb);
+ ext4_grpblk_t i = 0;
+ ext4_grpblk_t first;
+ ext4_grpblk_t len;
+ unsigned free = 0;
+ unsigned fragments = 0;
+ unsigned long long period = get_cycles();
+
+ /* initialize buddy from bitmap which is aggregation
+ * of on-disk bitmap and preallocations */
+ i = mb_find_next_zero_bit(bitmap, max, 0);
+ grp->bb_first_free = i;
+ while (i < max) {
+ fragments++;
+ first = i;
+ i = mb_find_next_bit(bitmap, max, i);
+ len = i - first;
+ free += len;
+ if (len > 1)
+ ext4_mb_mark_free_simple(sb, buddy, first, len, grp);
+ else
+ grp->bb_counters[0]++;
+ if (i < max)
+ i = mb_find_next_zero_bit(bitmap, max, i);
+ }
+ grp->bb_fragments = fragments;
+
+ if (free != grp->bb_free) {
+ ext4_grp_locked_error(sb, group, 0, 0,
+ "block bitmap and bg descriptor "
+ "inconsistent: %u vs %u free clusters",
+ free, grp->bb_free);
+ /*
+ * If we intend to continue, we consider group descriptor
+ * corrupt and update bb_free using bitmap value
+ */
+ grp->bb_free = free;
+ ext4_mark_group_bitmap_corrupted(sb, group,
+ EXT4_GROUP_INFO_BBITMAP_CORRUPT);
+ }
+ mb_set_largest_free_order(sb, grp);
+ mb_update_avg_fragment_size(sb, grp);
+
+ clear_bit(EXT4_GROUP_INFO_NEED_INIT_BIT, &(grp->bb_state));
+
+ period = get_cycles() - period;
+ atomic_inc(&sbi->s_mb_buddies_generated);
+ atomic64_add(period, &sbi->s_mb_generation_time);
+}
+
+static void mb_regenerate_buddy(struct ext4_buddy *e4b)
+{
+ int count;
+ int order = 1;
+ void *buddy;
+
+ while ((buddy = mb_find_buddy(e4b, order++, &count)))
+ mb_set_bits(buddy, 0, count);
+
+ e4b->bd_info->bb_fragments = 0;
+ memset(e4b->bd_info->bb_counters, 0,
+ sizeof(*e4b->bd_info->bb_counters) *
+ (e4b->bd_sb->s_blocksize_bits + 2));
+
+ ext4_mb_generate_buddy(e4b->bd_sb, e4b->bd_buddy,
+ e4b->bd_bitmap, e4b->bd_group, e4b->bd_info);
+}
+
+/* The buddy information is attached the buddy cache inode
+ * for convenience. The information regarding each group
+ * is loaded via ext4_mb_load_buddy. The information involve
+ * block bitmap and buddy information. The information are
+ * stored in the inode as
+ *
+ * { page }
+ * [ group 0 bitmap][ group 0 buddy] [group 1][ group 1]...
+ *
+ *
+ * one block each for bitmap and buddy information.
+ * So for each group we take up 2 blocks. A page can
+ * contain blocks_per_page (PAGE_SIZE / blocksize) blocks.
+ * So it can have information regarding groups_per_page which
+ * is blocks_per_page/2
+ *
+ * Locking note: This routine takes the block group lock of all groups
+ * for this page; do not hold this lock when calling this routine!
+ */
+
+static int ext4_mb_init_cache(struct folio *folio, char *incore, gfp_t gfp)
+{
+ ext4_group_t ngroups;
+ unsigned int blocksize;
+ int blocks_per_page;
+ int groups_per_page;
+ int err = 0;
+ int i;
+ ext4_group_t first_group, group;
+ int first_block;
+ struct super_block *sb;
+ struct buffer_head *bhs;
+ struct buffer_head **bh = NULL;
+ struct inode *inode;
+ char *data;
+ char *bitmap;
+ struct ext4_group_info *grinfo;
+
+ inode = folio->mapping->host;
+ sb = inode->i_sb;
+ ngroups = ext4_get_groups_count(sb);
+ blocksize = i_blocksize(inode);
+ blocks_per_page = PAGE_SIZE / blocksize;
+
+ mb_debug(sb, "init folio %lu\n", folio->index);
+
+ groups_per_page = blocks_per_page >> 1;
+ if (groups_per_page == 0)
+ groups_per_page = 1;
+
+ /* allocate buffer_heads to read bitmaps */
+ if (groups_per_page > 1) {
+ i = sizeof(struct buffer_head *) * groups_per_page;
+ bh = kzalloc(i, gfp);
+ if (bh == NULL)
+ return -ENOMEM;
+ } else
+ bh = &bhs;
+
+ first_group = folio->index * blocks_per_page / 2;
+
+ /* read all groups the folio covers into the cache */
+ for (i = 0, group = first_group; i < groups_per_page; i++, group++) {
+ if (group >= ngroups)
+ break;
+
+ grinfo = ext4_get_group_info(sb, group);
+ if (!grinfo)
+ continue;
+ /*
+ * If page is uptodate then we came here after online resize
+ * which added some new uninitialized group info structs, so
+ * we must skip all initialized uptodate buddies on the folio,
+ * which may be currently in use by an allocating task.
+ */
+ if (folio_test_uptodate(folio) &&
+ !EXT4_MB_GRP_NEED_INIT(grinfo)) {
+ bh[i] = NULL;
+ continue;
+ }
+ bh[i] = ext4_read_block_bitmap_nowait(sb, group, false);
+ if (IS_ERR(bh[i])) {
+ err = PTR_ERR(bh[i]);
+ bh[i] = NULL;
+ goto out;
+ }
+ mb_debug(sb, "read bitmap for group %u\n", group);
+ }
+
+ /* wait for I/O completion */
+ for (i = 0, group = first_group; i < groups_per_page; i++, group++) {
+ int err2;
+
+ if (!bh[i])
+ continue;
+ err2 = ext4_wait_block_bitmap(sb, group, bh[i]);
+ if (!err)
+ err = err2;
+ }
+
+ first_block = folio->index * blocks_per_page;
+ for (i = 0; i < blocks_per_page; i++) {
+ group = (first_block + i) >> 1;
+ if (group >= ngroups)
+ break;
+
+ if (!bh[group - first_group])
+ /* skip initialized uptodate buddy */
+ continue;
+
+ if (!buffer_verified(bh[group - first_group]))
+ /* Skip faulty bitmaps */
+ continue;
+ err = 0;
+
+ /*
+ * data carry information regarding this
+ * particular group in the format specified
+ * above
+ *
+ */
+ data = folio_address(folio) + (i * blocksize);
+ bitmap = bh[group - first_group]->b_data;
+
+ /*
+ * We place the buddy block and bitmap block
+ * close together
+ */
+ grinfo = ext4_get_group_info(sb, group);
+ if (!grinfo) {
+ err = -EFSCORRUPTED;
+ goto out;
+ }
+ if ((first_block + i) & 1) {
+ /* this is block of buddy */
+ BUG_ON(incore == NULL);
+ mb_debug(sb, "put buddy for group %u in folio %lu/%x\n",
+ group, folio->index, i * blocksize);
+ trace_ext4_mb_buddy_bitmap_load(sb, group);
+ grinfo->bb_fragments = 0;
+ memset(grinfo->bb_counters, 0,
+ sizeof(*grinfo->bb_counters) *
+ (MB_NUM_ORDERS(sb)));
+ /*
+ * incore got set to the group block bitmap below
+ */
+ ext4_lock_group(sb, group);
+ /* init the buddy */
+ memset(data, 0xff, blocksize);
+ ext4_mb_generate_buddy(sb, data, incore, group, grinfo);
+ ext4_unlock_group(sb, group);
+ incore = NULL;
+ } else {
+ /* this is block of bitmap */
+ BUG_ON(incore != NULL);
+ mb_debug(sb, "put bitmap for group %u in folio %lu/%x\n",
+ group, folio->index, i * blocksize);
+ trace_ext4_mb_bitmap_load(sb, group);
+
+ /* see comments in ext4_mb_put_pa() */
+ ext4_lock_group(sb, group);
+ memcpy(data, bitmap, blocksize);
+
+ /* mark all preallocated blks used in in-core bitmap */
+ ext4_mb_generate_from_pa(sb, data, group);
+ WARN_ON_ONCE(!RB_EMPTY_ROOT(&grinfo->bb_free_root));
+ ext4_unlock_group(sb, group);
+
+ /* set incore so that the buddy information can be
+ * generated using this
+ */
+ incore = data;
+ }
+ }
+ folio_mark_uptodate(folio);
+
+out:
+ if (bh) {
+ for (i = 0; i < groups_per_page; i++)
+ brelse(bh[i]);
+ if (bh != &bhs)
+ kfree(bh);
+ }
+ return err;
+}
+
+/*
+ * Lock the buddy and bitmap pages. This make sure other parallel init_group
+ * on the same buddy page doesn't happen whild holding the buddy page lock.
+ * Return locked buddy and bitmap pages on e4b struct. If buddy and bitmap
+ * are on the same page e4b->bd_buddy_folio is NULL and return value is 0.
+ */
+static int ext4_mb_get_buddy_page_lock(struct super_block *sb,
+ ext4_group_t group, struct ext4_buddy *e4b, gfp_t gfp)
+{
+ struct inode *inode = EXT4_SB(sb)->s_buddy_cache;
+ int block, pnum, poff;
+ int blocks_per_page;
+ struct folio *folio;
+
+ e4b->bd_buddy_folio = NULL;
+ e4b->bd_bitmap_folio = NULL;
+
+ blocks_per_page = PAGE_SIZE / sb->s_blocksize;
+ /*
+ * the buddy cache inode stores the block bitmap
+ * and buddy information in consecutive blocks.
+ * So for each group we need two blocks.
+ */
+ block = group * 2;
+ pnum = block / blocks_per_page;
+ poff = block % blocks_per_page;
+ folio = __filemap_get_folio(inode->i_mapping, pnum,
+ FGP_LOCK | FGP_ACCESSED | FGP_CREAT, gfp);
+ if (IS_ERR(folio))
+ return PTR_ERR(folio);
+ BUG_ON(folio->mapping != inode->i_mapping);
+ e4b->bd_bitmap_folio = folio;
+ e4b->bd_bitmap = folio_address(folio) + (poff * sb->s_blocksize);
+
+ if (blocks_per_page >= 2) {
+ /* buddy and bitmap are on the same page */
+ return 0;
+ }
+
+ /* blocks_per_page == 1, hence we need another page for the buddy */
+ folio = __filemap_get_folio(inode->i_mapping, block + 1,
+ FGP_LOCK | FGP_ACCESSED | FGP_CREAT, gfp);
+ if (IS_ERR(folio))
+ return PTR_ERR(folio);
+ BUG_ON(folio->mapping != inode->i_mapping);
+ e4b->bd_buddy_folio = folio;
+ return 0;
+}
+
+static void ext4_mb_put_buddy_page_lock(struct ext4_buddy *e4b)
+{
+ if (e4b->bd_bitmap_folio) {
+ folio_unlock(e4b->bd_bitmap_folio);
+ folio_put(e4b->bd_bitmap_folio);
+ }
+ if (e4b->bd_buddy_folio) {
+ folio_unlock(e4b->bd_buddy_folio);
+ folio_put(e4b->bd_buddy_folio);
+ }
+}
+
+/*
+ * Locking note: This routine calls ext4_mb_init_cache(), which takes the
+ * block group lock of all groups for this page; do not hold the BG lock when
+ * calling this routine!
+ */
+static noinline_for_stack
+int ext4_mb_init_group(struct super_block *sb, ext4_group_t group, gfp_t gfp)
+{
+
+ struct ext4_group_info *this_grp;
+ struct ext4_buddy e4b;
+ struct folio *folio;
+ int ret = 0;
+
+ might_sleep();
+ mb_debug(sb, "init group %u\n", group);
+ this_grp = ext4_get_group_info(sb, group);
+ if (!this_grp)
+ return -EFSCORRUPTED;
+
+ /*
+ * This ensures that we don't reinit the buddy cache
+ * page which map to the group from which we are already
+ * allocating. If we are looking at the buddy cache we would
+ * have taken a reference using ext4_mb_load_buddy and that
+ * would have pinned buddy page to page cache.
+ * The call to ext4_mb_get_buddy_page_lock will mark the
+ * page accessed.
+ */
+ ret = ext4_mb_get_buddy_page_lock(sb, group, &e4b, gfp);
+ if (ret || !EXT4_MB_GRP_NEED_INIT(this_grp)) {
+ /*
+ * somebody initialized the group
+ * return without doing anything
+ */
+ goto err;
+ }
+
+ folio = e4b.bd_bitmap_folio;
+ ret = ext4_mb_init_cache(folio, NULL, gfp);
+ if (ret)
+ goto err;
+ if (!folio_test_uptodate(folio)) {
+ ret = -EIO;
+ goto err;
+ }
+
+ if (e4b.bd_buddy_folio == NULL) {
+ /*
+ * If both the bitmap and buddy are in
+ * the same page we don't need to force
+ * init the buddy
+ */
+ ret = 0;
+ goto err;
+ }
+ /* init buddy cache */
+ folio = e4b.bd_buddy_folio;
+ ret = ext4_mb_init_cache(folio, e4b.bd_bitmap, gfp);
+ if (ret)
+ goto err;
+ if (!folio_test_uptodate(folio)) {
+ ret = -EIO;
+ goto err;
+ }
+err:
+ ext4_mb_put_buddy_page_lock(&e4b);
+ return ret;
+}
+
+/*
+ * Locking note: This routine calls ext4_mb_init_cache(), which takes the
+ * block group lock of all groups for this page; do not hold the BG lock when
+ * calling this routine!
+ */
+static noinline_for_stack int
+ext4_mb_load_buddy_gfp(struct super_block *sb, ext4_group_t group,
+ struct ext4_buddy *e4b, gfp_t gfp)
+{
+ int blocks_per_page;
+ int block;
+ int pnum;
+ int poff;
+ struct folio *folio;
+ int ret;
+ struct ext4_group_info *grp;
+ struct ext4_sb_info *sbi = EXT4_SB(sb);
+ struct inode *inode = sbi->s_buddy_cache;
+
+ might_sleep();
+ mb_debug(sb, "load group %u\n", group);
+
+ blocks_per_page = PAGE_SIZE / sb->s_blocksize;
+ grp = ext4_get_group_info(sb, group);
+ if (!grp)
+ return -EFSCORRUPTED;
+
+ e4b->bd_blkbits = sb->s_blocksize_bits;
+ e4b->bd_info = grp;
+ e4b->bd_sb = sb;
+ e4b->bd_group = group;
+ e4b->bd_buddy_folio = NULL;
+ e4b->bd_bitmap_folio = NULL;
+
+ if (unlikely(EXT4_MB_GRP_NEED_INIT(grp))) {
+ /*
+ * we need full data about the group
+ * to make a good selection
+ */
+ ret = ext4_mb_init_group(sb, group, gfp);
+ if (ret)
+ return ret;
+ }
+
+ /*
+ * the buddy cache inode stores the block bitmap
+ * and buddy information in consecutive blocks.
+ * So for each group we need two blocks.
+ */
+ block = group * 2;
+ pnum = block / blocks_per_page;
+ poff = block % blocks_per_page;
+
+ /* Avoid locking the folio in the fast path ... */
+ folio = __filemap_get_folio(inode->i_mapping, pnum, FGP_ACCESSED, 0);
+ if (IS_ERR(folio) || !folio_test_uptodate(folio)) {
+ if (!IS_ERR(folio))
+ /*
+ * drop the folio reference and try
+ * to get the folio with lock. If we
+ * are not uptodate that implies
+ * somebody just created the folio but
+ * is yet to initialize it. So
+ * wait for it to initialize.
+ */
+ folio_put(folio);
+ folio = __filemap_get_folio(inode->i_mapping, pnum,
+ FGP_LOCK | FGP_ACCESSED | FGP_CREAT, gfp);
+ if (!IS_ERR(folio)) {
+ if (WARN_RATELIMIT(folio->mapping != inode->i_mapping,
+ "ext4: bitmap's mapping != inode->i_mapping\n")) {
+ /* should never happen */
+ folio_unlock(folio);
+ ret = -EINVAL;
+ goto err;
+ }
+ if (!folio_test_uptodate(folio)) {
+ ret = ext4_mb_init_cache(folio, NULL, gfp);
+ if (ret) {
+ folio_unlock(folio);
+ goto err;
+ }
+ mb_cmp_bitmaps(e4b, folio_address(folio) +
+ (poff * sb->s_blocksize));
+ }
+ folio_unlock(folio);
+ }
+ }
+ if (IS_ERR(folio)) {
+ ret = PTR_ERR(folio);
+ goto err;
+ }
+ if (!folio_test_uptodate(folio)) {
+ ret = -EIO;
+ goto err;
+ }
+
+ /* Folios marked accessed already */
+ e4b->bd_bitmap_folio = folio;
+ e4b->bd_bitmap = folio_address(folio) + (poff * sb->s_blocksize);
+
+ block++;
+ pnum = block / blocks_per_page;
+ poff = block % blocks_per_page;
+
+ folio = __filemap_get_folio(inode->i_mapping, pnum, FGP_ACCESSED, 0);
+ if (IS_ERR(folio) || !folio_test_uptodate(folio)) {
+ if (!IS_ERR(folio))
+ folio_put(folio);
+ folio = __filemap_get_folio(inode->i_mapping, pnum,
+ FGP_LOCK | FGP_ACCESSED | FGP_CREAT, gfp);
+ if (!IS_ERR(folio)) {
+ if (WARN_RATELIMIT(folio->mapping != inode->i_mapping,
+ "ext4: buddy bitmap's mapping != inode->i_mapping\n")) {
+ /* should never happen */
+ folio_unlock(folio);
+ ret = -EINVAL;
+ goto err;
+ }
+ if (!folio_test_uptodate(folio)) {
+ ret = ext4_mb_init_cache(folio, e4b->bd_bitmap,
+ gfp);
+ if (ret) {
+ folio_unlock(folio);
+ goto err;
+ }
+ }
+ folio_unlock(folio);
+ }
+ }
+ if (IS_ERR(folio)) {
+ ret = PTR_ERR(folio);
+ goto err;
+ }
+ if (!folio_test_uptodate(folio)) {
+ ret = -EIO;
+ goto err;
+ }
+
+ /* Folios marked accessed already */
+ e4b->bd_buddy_folio = folio;
+ e4b->bd_buddy = folio_address(folio) + (poff * sb->s_blocksize);
+
+ return 0;
+
+err:
+ if (!IS_ERR_OR_NULL(folio))
+ folio_put(folio);
+ if (e4b->bd_bitmap_folio)
+ folio_put(e4b->bd_bitmap_folio);
+
+ e4b->bd_buddy = NULL;
+ e4b->bd_bitmap = NULL;
+ return ret;
+}
+
+static int ext4_mb_load_buddy(struct super_block *sb, ext4_group_t group,
+ struct ext4_buddy *e4b)
+{
+ return ext4_mb_load_buddy_gfp(sb, group, e4b, GFP_NOFS);
+}
+
+static void ext4_mb_unload_buddy(struct ext4_buddy *e4b)
+{
+ if (e4b->bd_bitmap_folio)
+ folio_put(e4b->bd_bitmap_folio);
+ if (e4b->bd_buddy_folio)
+ folio_put(e4b->bd_buddy_folio);
+}
+
+
+static int mb_find_order_for_block(struct ext4_buddy *e4b, int block)
+{
+ int order = 1, max;
+ void *bb;
+
+ BUG_ON(e4b->bd_bitmap == e4b->bd_buddy);
+ BUG_ON(block >= (1 << (e4b->bd_blkbits + 3)));
+
+ while (order <= e4b->bd_blkbits + 1) {
+ bb = mb_find_buddy(e4b, order, &max);
+ if (!mb_test_bit(block >> order, bb)) {
+ /* this block is part of buddy of order 'order' */
+ return order;
+ }
+ order++;
+ }
+ return 0;
+}
+
+static void mb_clear_bits(void *bm, int cur, int len)
+{
+ __u32 *addr;
+
+ len = cur + len;
+ while (cur < len) {
+ if ((cur & 31) == 0 && (len - cur) >= 32) {
+ /* fast path: clear whole word at once */
+ addr = bm + (cur >> 3);
+ *addr = 0;
+ cur += 32;
+ continue;
+ }
+ mb_clear_bit(cur, bm);
+ cur++;
+ }
+}
+
+/* clear bits in given range
+ * will return first found zero bit if any, -1 otherwise
+ */
+static int mb_test_and_clear_bits(void *bm, int cur, int len)
+{
+ __u32 *addr;
+ int zero_bit = -1;
+
+ len = cur + len;
+ while (cur < len) {
+ if ((cur & 31) == 0 && (len - cur) >= 32) {
+ /* fast path: clear whole word at once */
+ addr = bm + (cur >> 3);
+ if (*addr != (__u32)(-1) && zero_bit == -1)
+ zero_bit = cur + mb_find_next_zero_bit(addr, 32, 0);
+ *addr = 0;
+ cur += 32;
+ continue;
+ }
+ if (!mb_test_and_clear_bit(cur, bm) && zero_bit == -1)
+ zero_bit = cur;
+ cur++;
+ }
+
+ return zero_bit;
+}
+
+void mb_set_bits(void *bm, int cur, int len)
+{
+ __u32 *addr;
+
+ len = cur + len;
+ while (cur < len) {
+ if ((cur & 31) == 0 && (len - cur) >= 32) {
+ /* fast path: set whole word at once */
+ addr = bm + (cur >> 3);
+ *addr = 0xffffffff;
+ cur += 32;
+ continue;
+ }
+ mb_set_bit(cur, bm);
+ cur++;
+ }
+}
+
+static inline int mb_buddy_adjust_border(int* bit, void* bitmap, int side)
+{
+ if (mb_test_bit(*bit + side, bitmap)) {
+ mb_clear_bit(*bit, bitmap);
+ (*bit) -= side;
+ return 1;
+ }
+ else {
+ (*bit) += side;
+ mb_set_bit(*bit, bitmap);
+ return -1;
+ }
+}
+
+static void mb_buddy_mark_free(struct ext4_buddy *e4b, int first, int last)
+{
+ int max;
+ int order = 1;
+ void *buddy = mb_find_buddy(e4b, order, &max);
+
+ while (buddy) {
+ void *buddy2;
+
+ /* Bits in range [first; last] are known to be set since
+ * corresponding blocks were allocated. Bits in range
+ * (first; last) will stay set because they form buddies on
+ * upper layer. We just deal with borders if they don't
+ * align with upper layer and then go up.
+ * Releasing entire group is all about clearing
+ * single bit of highest order buddy.
+ */
+
+ /* Example:
+ * ---------------------------------
+ * | 1 | 1 | 1 | 1 |
+ * ---------------------------------
+ * | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
+ * ---------------------------------
+ * 0 1 2 3 4 5 6 7
+ * \_____________________/
+ *
+ * Neither [1] nor [6] is aligned to above layer.
+ * Left neighbour [0] is free, so mark it busy,
+ * decrease bb_counters and extend range to
+ * [0; 6]
+ * Right neighbour [7] is busy. It can't be coaleasced with [6], so
+ * mark [6] free, increase bb_counters and shrink range to
+ * [0; 5].
+ * Then shift range to [0; 2], go up and do the same.
+ */
+
+
+ if (first & 1)
+ e4b->bd_info->bb_counters[order] += mb_buddy_adjust_border(&first, buddy, -1);
+ if (!(last & 1))
+ e4b->bd_info->bb_counters[order] += mb_buddy_adjust_border(&last, buddy, 1);
+ if (first > last)
+ break;
+ order++;
+
+ buddy2 = mb_find_buddy(e4b, order, &max);
+ if (!buddy2) {
+ mb_clear_bits(buddy, first, last - first + 1);
+ e4b->bd_info->bb_counters[order - 1] += last - first + 1;
+ break;
+ }
+ first >>= 1;
+ last >>= 1;
+ buddy = buddy2;
+ }
+}
+
+static void mb_free_blocks(struct inode *inode, struct ext4_buddy *e4b,
+ int first, int count)
+{
+ int left_is_free = 0;
+ int right_is_free = 0;
+ int block;
+ int last = first + count - 1;
+ struct super_block *sb = e4b->bd_sb;
+
+ if (WARN_ON(count == 0))
+ return;
+ BUG_ON(last >= (sb->s_blocksize << 3));
+ assert_spin_locked(ext4_group_lock_ptr(sb, e4b->bd_group));
+ /* Don't bother if the block group is corrupt. */
+ if (unlikely(EXT4_MB_GRP_BBITMAP_CORRUPT(e4b->bd_info)))
+ return;
+
+ mb_check_buddy(e4b);
+ mb_free_blocks_double(inode, e4b, first, count);
+
+ /* access memory sequentially: check left neighbour,
+ * clear range and then check right neighbour
+ */
+ if (first != 0)
+ left_is_free = !mb_test_bit(first - 1, e4b->bd_bitmap);
+ block = mb_test_and_clear_bits(e4b->bd_bitmap, first, count);
+ if (last + 1 < EXT4_SB(sb)->s_mb_maxs[0])
+ right_is_free = !mb_test_bit(last + 1, e4b->bd_bitmap);
+
+ if (unlikely(block != -1)) {
+ struct ext4_sb_info *sbi = EXT4_SB(sb);
+ ext4_fsblk_t blocknr;
+
+ /*
+ * Fastcommit replay can free already freed blocks which
+ * corrupts allocation info. Regenerate it.
+ */
+ if (sbi->s_mount_state & EXT4_FC_REPLAY) {
+ mb_regenerate_buddy(e4b);
+ goto check;
+ }
+
+ blocknr = ext4_group_first_block_no(sb, e4b->bd_group);
+ blocknr += EXT4_C2B(sbi, block);
+ ext4_mark_group_bitmap_corrupted(sb, e4b->bd_group,
+ EXT4_GROUP_INFO_BBITMAP_CORRUPT);
+ ext4_grp_locked_error(sb, e4b->bd_group,
+ inode ? inode->i_ino : 0, blocknr,
+ "freeing already freed block (bit %u); block bitmap corrupt.",
+ block);
+ return;
+ }
+
+ this_cpu_inc(discard_pa_seq);
+ e4b->bd_info->bb_free += count;
+ if (first < e4b->bd_info->bb_first_free)
+ e4b->bd_info->bb_first_free = first;
+
+ /* let's maintain fragments counter */
+ if (left_is_free && right_is_free)
+ e4b->bd_info->bb_fragments--;
+ else if (!left_is_free && !right_is_free)
+ e4b->bd_info->bb_fragments++;
+
+ /* buddy[0] == bd_bitmap is a special case, so handle
+ * it right away and let mb_buddy_mark_free stay free of
+ * zero order checks.
+ * Check if neighbours are to be coaleasced,
+ * adjust bitmap bb_counters and borders appropriately.
+ */
+ if (first & 1) {
+ first += !left_is_free;
+ e4b->bd_info->bb_counters[0] += left_is_free ? -1 : 1;
+ }
+ if (!(last & 1)) {
+ last -= !right_is_free;
+ e4b->bd_info->bb_counters[0] += right_is_free ? -1 : 1;
+ }
+
+ if (first <= last)
+ mb_buddy_mark_free(e4b, first >> 1, last >> 1);
+
+ mb_set_largest_free_order(sb, e4b->bd_info);
+ mb_update_avg_fragment_size(sb, e4b->bd_info);
+check:
+ mb_check_buddy(e4b);
+}
+
+static int mb_find_extent(struct ext4_buddy *e4b, int block,
+ int needed, struct ext4_free_extent *ex)
+{
+ int max, order, next;
+ void *buddy;
+
+ assert_spin_locked(ext4_group_lock_ptr(e4b->bd_sb, e4b->bd_group));
+ BUG_ON(ex == NULL);
+
+ buddy = mb_find_buddy(e4b, 0, &max);
+ BUG_ON(buddy == NULL);
+ BUG_ON(block >= max);
+ if (mb_test_bit(block, buddy)) {
+ ex->fe_len = 0;
+ ex->fe_start = 0;
+ ex->fe_group = 0;
+ return 0;
+ }
+
+ /* find actual order */
+ order = mb_find_order_for_block(e4b, block);
+
+ ex->fe_len = (1 << order) - (block & ((1 << order) - 1));
+ ex->fe_start = block;
+ ex->fe_group = e4b->bd_group;
+
+ block = block >> order;
+
+ while (needed > ex->fe_len &&
+ mb_find_buddy(e4b, order, &max)) {
+
+ if (block + 1 >= max)
+ break;
+
+ next = (block + 1) * (1 << order);
+ if (mb_test_bit(next, e4b->bd_bitmap))
+ break;
+
+ order = mb_find_order_for_block(e4b, next);
+
+ block = next >> order;
+ ex->fe_len += 1 << order;
+ }
+
+ if (ex->fe_start + ex->fe_len > EXT4_CLUSTERS_PER_GROUP(e4b->bd_sb)) {
+ /* Should never happen! (but apparently sometimes does?!?) */
+ WARN_ON(1);
+ ext4_grp_locked_error(e4b->bd_sb, e4b->bd_group, 0, 0,
+ "corruption or bug in mb_find_extent "
+ "block=%d, order=%d needed=%d ex=%u/%d/%d@%u",
+ block, order, needed, ex->fe_group, ex->fe_start,
+ ex->fe_len, ex->fe_logical);
+ ex->fe_len = 0;
+ ex->fe_start = 0;
+ ex->fe_group = 0;
+ }
+ return ex->fe_len;
+}
+
+static int mb_mark_used(struct ext4_buddy *e4b, struct ext4_free_extent *ex)
+{
+ int ord;
+ int mlen = 0;
+ int max = 0;
+ int start = ex->fe_start;
+ int len = ex->fe_len;
+ unsigned ret = 0;
+ int len0 = len;
+ void *buddy;
+ int ord_start, ord_end;
+
+ BUG_ON(start + len > (e4b->bd_sb->s_blocksize << 3));
+ BUG_ON(e4b->bd_group != ex->fe_group);
+ assert_spin_locked(ext4_group_lock_ptr(e4b->bd_sb, e4b->bd_group));
+ mb_check_buddy(e4b);
+ mb_mark_used_double(e4b, start, len);
+
+ this_cpu_inc(discard_pa_seq);
+ e4b->bd_info->bb_free -= len;
+ if (e4b->bd_info->bb_first_free == start)
+ e4b->bd_info->bb_first_free += len;
+
+ /* let's maintain fragments counter */
+ if (start != 0)
+ mlen = !mb_test_bit(start - 1, e4b->bd_bitmap);
+ if (start + len < EXT4_SB(e4b->bd_sb)->s_mb_maxs[0])
+ max = !mb_test_bit(start + len, e4b->bd_bitmap);
+ if (mlen && max)
+ e4b->bd_info->bb_fragments++;
+ else if (!mlen && !max)
+ e4b->bd_info->bb_fragments--;
+
+ /* let's maintain buddy itself */
+ while (len) {
+ ord = mb_find_order_for_block(e4b, start);
+
+ if (((start >> ord) << ord) == start && len >= (1 << ord)) {
+ /* the whole chunk may be allocated at once! */
+ mlen = 1 << ord;
+ buddy = mb_find_buddy(e4b, ord, &max);
+ BUG_ON((start >> ord) >= max);
+ mb_set_bit(start >> ord, buddy);
+ e4b->bd_info->bb_counters[ord]--;
+ start += mlen;
+ len -= mlen;
+ BUG_ON(len < 0);
+ continue;
+ }
+
+ /* store for history */
+ if (ret == 0)
+ ret = len | (ord << 16);
+
+ BUG_ON(ord <= 0);
+ buddy = mb_find_buddy(e4b, ord, &max);
+ mb_set_bit(start >> ord, buddy);
+ e4b->bd_info->bb_counters[ord]--;
+
+ ord_start = (start >> ord) << ord;
+ ord_end = ord_start + (1 << ord);
+ /* first chunk */
+ if (start > ord_start)
+ ext4_mb_mark_free_simple(e4b->bd_sb, e4b->bd_buddy,
+ ord_start, start - ord_start,
+ e4b->bd_info);
+
+ /* last chunk */
+ if (start + len < ord_end) {
+ ext4_mb_mark_free_simple(e4b->bd_sb, e4b->bd_buddy,
+ start + len,
+ ord_end - (start + len),
+ e4b->bd_info);
+ break;
+ }
+ len = start + len - ord_end;
+ start = ord_end;
+ }
+ mb_set_largest_free_order(e4b->bd_sb, e4b->bd_info);
+
+ mb_update_avg_fragment_size(e4b->bd_sb, e4b->bd_info);
+ mb_set_bits(e4b->bd_bitmap, ex->fe_start, len0);
+ mb_check_buddy(e4b);
+
+ return ret;
+}
+
+/*
+ * Must be called under group lock!
+ */
+static void ext4_mb_use_best_found(struct ext4_allocation_context *ac,
+ struct ext4_buddy *e4b)
+{
+ struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
+ int ret;
+
+ BUG_ON(ac->ac_b_ex.fe_group != e4b->bd_group);
+ BUG_ON(ac->ac_status == AC_STATUS_FOUND);
+
+ ac->ac_b_ex.fe_len = min(ac->ac_b_ex.fe_len, ac->ac_g_ex.fe_len);
+ ac->ac_b_ex.fe_logical = ac->ac_g_ex.fe_logical;
+ ret = mb_mark_used(e4b, &ac->ac_b_ex);
+
+ /* preallocation can change ac_b_ex, thus we store actually
+ * allocated blocks for history */
+ ac->ac_f_ex = ac->ac_b_ex;
+
+ ac->ac_status = AC_STATUS_FOUND;
+ ac->ac_tail = ret & 0xffff;
+ ac->ac_buddy = ret >> 16;
+
+ /*
+ * take the page reference. We want the page to be pinned
+ * so that we don't get a ext4_mb_init_cache_call for this
+ * group until we update the bitmap. That would mean we
+ * double allocate blocks. The reference is dropped
+ * in ext4_mb_release_context
+ */
+ ac->ac_bitmap_folio = e4b->bd_bitmap_folio;
+ folio_get(ac->ac_bitmap_folio);
+ ac->ac_buddy_folio = e4b->bd_buddy_folio;
+ folio_get(ac->ac_buddy_folio);
+ /* store last allocated for subsequent stream allocation */
+ if (ac->ac_flags & EXT4_MB_STREAM_ALLOC) {
+ int hash = ac->ac_inode->i_ino % sbi->s_mb_nr_global_goals;
+
+ WRITE_ONCE(sbi->s_mb_last_groups[hash], ac->ac_f_ex.fe_group);
+ }
+
+ /*
+ * As we've just preallocated more space than
+ * user requested originally, we store allocated
+ * space in a special descriptor.
+ */
+ if (ac->ac_o_ex.fe_len < ac->ac_b_ex.fe_len)
+ ext4_mb_new_preallocation(ac);
+
+}
+
+static void ext4_mb_check_limits(struct ext4_allocation_context *ac,
+ struct ext4_buddy *e4b,
+ int finish_group)
+{
+ struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
+ struct ext4_free_extent *bex = &ac->ac_b_ex;
+ struct ext4_free_extent *gex = &ac->ac_g_ex;
+
+ if (ac->ac_status == AC_STATUS_FOUND)
+ return;
+ /*
+ * We don't want to scan for a whole year
+ */
+ if (ac->ac_found > sbi->s_mb_max_to_scan &&
+ !(ac->ac_flags & EXT4_MB_HINT_FIRST)) {
+ ac->ac_status = AC_STATUS_BREAK;
+ return;
+ }
+
+ /*
+ * Haven't found good chunk so far, let's continue
+ */
+ if (bex->fe_len < gex->fe_len)
+ return;
+
+ if (finish_group || ac->ac_found > sbi->s_mb_min_to_scan)
+ ext4_mb_use_best_found(ac, e4b);
+}
+
+/*
+ * The routine checks whether found extent is good enough. If it is,
+ * then the extent gets marked used and flag is set to the context
+ * to stop scanning. Otherwise, the extent is compared with the
+ * previous found extent and if new one is better, then it's stored
+ * in the context. Later, the best found extent will be used, if
+ * mballoc can't find good enough extent.
+ *
+ * The algorithm used is roughly as follows:
+ *
+ * * If free extent found is exactly as big as goal, then
+ * stop the scan and use it immediately
+ *
+ * * If free extent found is smaller than goal, then keep retrying
+ * upto a max of sbi->s_mb_max_to_scan times (default 200). After
+ * that stop scanning and use whatever we have.
+ *
+ * * If free extent found is bigger than goal, then keep retrying
+ * upto a max of sbi->s_mb_min_to_scan times (default 10) before
+ * stopping the scan and using the extent.
+ *
+ *
+ * FIXME: real allocation policy is to be designed yet!
+ */
+static void ext4_mb_measure_extent(struct ext4_allocation_context *ac,
+ struct ext4_free_extent *ex,
+ struct ext4_buddy *e4b)
+{
+ struct ext4_free_extent *bex = &ac->ac_b_ex;
+ struct ext4_free_extent *gex = &ac->ac_g_ex;
+
+ BUG_ON(ex->fe_len <= 0);
+ BUG_ON(ex->fe_len > EXT4_CLUSTERS_PER_GROUP(ac->ac_sb));
+ BUG_ON(ex->fe_start >= EXT4_CLUSTERS_PER_GROUP(ac->ac_sb));
+ BUG_ON(ac->ac_status != AC_STATUS_CONTINUE);
+
+ ac->ac_found++;
+ ac->ac_cX_found[ac->ac_criteria]++;
+
+ /*
+ * The special case - take what you catch first
+ */
+ if (unlikely(ac->ac_flags & EXT4_MB_HINT_FIRST)) {
+ *bex = *ex;
+ ext4_mb_use_best_found(ac, e4b);
+ return;
+ }
+
+ /*
+ * Let's check whether the chuck is good enough
+ */
+ if (ex->fe_len == gex->fe_len) {
+ *bex = *ex;
+ ext4_mb_use_best_found(ac, e4b);
+ return;
+ }
+
+ /*
+ * If this is first found extent, just store it in the context
+ */
+ if (bex->fe_len == 0) {
+ *bex = *ex;
+ return;
+ }
+
+ /*
+ * If new found extent is better, store it in the context
+ */
+ if (bex->fe_len < gex->fe_len) {
+ /* if the request isn't satisfied, any found extent
+ * larger than previous best one is better */
+ if (ex->fe_len > bex->fe_len)
+ *bex = *ex;
+ } else if (ex->fe_len > gex->fe_len) {
+ /* if the request is satisfied, then we try to find
+ * an extent that still satisfy the request, but is
+ * smaller than previous one */
+ if (ex->fe_len < bex->fe_len)
+ *bex = *ex;
+ }
+
+ ext4_mb_check_limits(ac, e4b, 0);
+}
+
+static noinline_for_stack
+void ext4_mb_try_best_found(struct ext4_allocation_context *ac,
+ struct ext4_buddy *e4b)
+{
+ struct ext4_free_extent ex = ac->ac_b_ex;
+ ext4_group_t group = ex.fe_group;
+ int max;
+ int err;
+
+ BUG_ON(ex.fe_len <= 0);
+ err = ext4_mb_load_buddy(ac->ac_sb, group, e4b);
+ if (err)
+ return;
+
+ ext4_lock_group(ac->ac_sb, group);
+ if (unlikely(EXT4_MB_GRP_BBITMAP_CORRUPT(e4b->bd_info)))
+ goto out;
+
+ max = mb_find_extent(e4b, ex.fe_start, ex.fe_len, &ex);
+
+ if (max > 0) {
+ ac->ac_b_ex = ex;
+ ext4_mb_use_best_found(ac, e4b);
+ }
+
+out:
+ ext4_unlock_group(ac->ac_sb, group);
+ ext4_mb_unload_buddy(e4b);
+}
+
+static noinline_for_stack
+int ext4_mb_find_by_goal(struct ext4_allocation_context *ac,
+ struct ext4_buddy *e4b)
+{
+ ext4_group_t group = ac->ac_g_ex.fe_group;
+ int max;
+ int err;
+ struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
+ struct ext4_group_info *grp = ext4_get_group_info(ac->ac_sb, group);
+ struct ext4_free_extent ex;
+
+ if (!grp)
+ return -EFSCORRUPTED;
+ if (!(ac->ac_flags & (EXT4_MB_HINT_TRY_GOAL | EXT4_MB_HINT_GOAL_ONLY)))
+ return 0;
+ if (grp->bb_free == 0)
+ return 0;
+
+ err = ext4_mb_load_buddy(ac->ac_sb, group, e4b);
+ if (err)
+ return err;
+
+ ext4_lock_group(ac->ac_sb, group);
+ if (unlikely(EXT4_MB_GRP_BBITMAP_CORRUPT(e4b->bd_info)))
+ goto out;
+
+ max = mb_find_extent(e4b, ac->ac_g_ex.fe_start,
+ ac->ac_g_ex.fe_len, &ex);
+ ex.fe_logical = 0xDEADFA11; /* debug value */
+
+ if (max >= ac->ac_g_ex.fe_len &&
+ ac->ac_g_ex.fe_len == EXT4_NUM_B2C(sbi, sbi->s_stripe)) {
+ ext4_fsblk_t start;
+
+ start = ext4_grp_offs_to_block(ac->ac_sb, &ex);
+ /* use do_div to get remainder (would be 64-bit modulo) */
+ if (do_div(start, sbi->s_stripe) == 0) {
+ ac->ac_found++;
+ ac->ac_b_ex = ex;
+ ext4_mb_use_best_found(ac, e4b);
+ }
+ } else if (max >= ac->ac_g_ex.fe_len) {
+ BUG_ON(ex.fe_len <= 0);
+ BUG_ON(ex.fe_group != ac->ac_g_ex.fe_group);
+ BUG_ON(ex.fe_start != ac->ac_g_ex.fe_start);
+ ac->ac_found++;
+ ac->ac_b_ex = ex;
+ ext4_mb_use_best_found(ac, e4b);
+ } else if (max > 0 && (ac->ac_flags & EXT4_MB_HINT_MERGE)) {
+ /* Sometimes, caller may want to merge even small
+ * number of blocks to an existing extent */
+ BUG_ON(ex.fe_len <= 0);
+ BUG_ON(ex.fe_group != ac->ac_g_ex.fe_group);
+ BUG_ON(ex.fe_start != ac->ac_g_ex.fe_start);
+ ac->ac_found++;
+ ac->ac_b_ex = ex;
+ ext4_mb_use_best_found(ac, e4b);
+ }
+out:
+ ext4_unlock_group(ac->ac_sb, group);
+ ext4_mb_unload_buddy(e4b);
+
+ return 0;
+}
+
+/*
+ * The routine scans buddy structures (not bitmap!) from given order
+ * to max order and tries to find big enough chunk to satisfy the req
+ */
+static noinline_for_stack
+void ext4_mb_simple_scan_group(struct ext4_allocation_context *ac,
+ struct ext4_buddy *e4b)
+{
+ struct super_block *sb = ac->ac_sb;
+ struct ext4_group_info *grp = e4b->bd_info;
+ void *buddy;
+ int i;
+ int k;
+ int max;
+
+ BUG_ON(ac->ac_2order <= 0);
+ for (i = ac->ac_2order; i < MB_NUM_ORDERS(sb); i++) {
+ if (grp->bb_counters[i] == 0)
+ continue;
+
+ buddy = mb_find_buddy(e4b, i, &max);
+ if (WARN_RATELIMIT(buddy == NULL,
+ "ext4: mb_simple_scan_group: mb_find_buddy failed, (%d)\n", i))
+ continue;
+
+ k = mb_find_next_zero_bit(buddy, max, 0);
+ if (k >= max) {
+ ext4_mark_group_bitmap_corrupted(ac->ac_sb,
+ e4b->bd_group,
+ EXT4_GROUP_INFO_BBITMAP_CORRUPT);
+ ext4_grp_locked_error(ac->ac_sb, e4b->bd_group, 0, 0,
+ "%d free clusters of order %d. But found 0",
+ grp->bb_counters[i], i);
+ break;
+ }
+ ac->ac_found++;
+ ac->ac_cX_found[ac->ac_criteria]++;
+
+ ac->ac_b_ex.fe_len = 1 << i;
+ ac->ac_b_ex.fe_start = k << i;
+ ac->ac_b_ex.fe_group = e4b->bd_group;
+
+ ext4_mb_use_best_found(ac, e4b);
+
+ BUG_ON(ac->ac_f_ex.fe_len != ac->ac_g_ex.fe_len);
+
+ if (EXT4_SB(sb)->s_mb_stats)
+ atomic_inc(&EXT4_SB(sb)->s_bal_2orders);
+
+ break;
+ }
+}
+
+/*
+ * The routine scans the group and measures all found extents.
+ * In order to optimize scanning, caller must pass number of
+ * free blocks in the group, so the routine can know upper limit.
+ */
+static noinline_for_stack
+void ext4_mb_complex_scan_group(struct ext4_allocation_context *ac,
+ struct ext4_buddy *e4b)
+{
+ struct super_block *sb = ac->ac_sb;
+ void *bitmap = e4b->bd_bitmap;
+ struct ext4_free_extent ex;
+ int i, j, freelen;
+ int free;
+
+ free = e4b->bd_info->bb_free;
+ if (WARN_ON(free <= 0))
+ return;
+
+ i = e4b->bd_info->bb_first_free;
+
+ while (free && ac->ac_status == AC_STATUS_CONTINUE) {
+ i = mb_find_next_zero_bit(bitmap,
+ EXT4_CLUSTERS_PER_GROUP(sb), i);
+ if (i >= EXT4_CLUSTERS_PER_GROUP(sb)) {
+ /*
+ * IF we have corrupt bitmap, we won't find any
+ * free blocks even though group info says we
+ * have free blocks
+ */
+ ext4_mark_group_bitmap_corrupted(sb, e4b->bd_group,
+ EXT4_GROUP_INFO_BBITMAP_CORRUPT);
+ ext4_grp_locked_error(sb, e4b->bd_group, 0, 0,
+ "%d free clusters as per "
+ "group info. But bitmap says 0",
+ free);
+ break;
+ }
+
+ if (!ext4_mb_cr_expensive(ac->ac_criteria)) {
+ /*
+ * In CR_GOAL_LEN_FAST and CR_BEST_AVAIL_LEN, we are
+ * sure that this group will have a large enough
+ * continuous free extent, so skip over the smaller free
+ * extents
+ */
+ j = mb_find_next_bit(bitmap,
+ EXT4_CLUSTERS_PER_GROUP(sb), i);
+ freelen = j - i;
+
+ if (freelen < ac->ac_g_ex.fe_len) {
+ i = j;
+ free -= freelen;
+ continue;
+ }
+ }
+
+ mb_find_extent(e4b, i, ac->ac_g_ex.fe_len, &ex);
+ if (WARN_ON(ex.fe_len <= 0))
+ break;
+ if (free < ex.fe_len) {
+ ext4_mark_group_bitmap_corrupted(sb, e4b->bd_group,
+ EXT4_GROUP_INFO_BBITMAP_CORRUPT);
+ ext4_grp_locked_error(sb, e4b->bd_group, 0, 0,
+ "%d free clusters as per "
+ "group info. But got %d blocks",
+ free, ex.fe_len);
+ /*
+ * The number of free blocks differs. This mostly
+ * indicate that the bitmap is corrupt. So exit
+ * without claiming the space.
+ */
+ break;
+ }
+ ex.fe_logical = 0xDEADC0DE; /* debug value */
+ ext4_mb_measure_extent(ac, &ex, e4b);
+
+ i += ex.fe_len;
+ free -= ex.fe_len;
+ }
+
+ ext4_mb_check_limits(ac, e4b, 1);
+}
+
+/*
+ * This is a special case for storages like raid5
+ * we try to find stripe-aligned chunks for stripe-size-multiple requests
+ */
+static noinline_for_stack
+void ext4_mb_scan_aligned(struct ext4_allocation_context *ac,
+ struct ext4_buddy *e4b)
+{
+ struct super_block *sb = ac->ac_sb;
+ struct ext4_sb_info *sbi = EXT4_SB(sb);
+ void *bitmap = e4b->bd_bitmap;
+ struct ext4_free_extent ex;
+ ext4_fsblk_t first_group_block;
+ ext4_fsblk_t a;
+ ext4_grpblk_t i, stripe;
+ int max;
+
+ BUG_ON(sbi->s_stripe == 0);
+
+ /* find first stripe-aligned block in group */
+ first_group_block = ext4_group_first_block_no(sb, e4b->bd_group);
+
+ a = first_group_block + sbi->s_stripe - 1;
+ do_div(a, sbi->s_stripe);
+ i = (a * sbi->s_stripe) - first_group_block;
+
+ stripe = EXT4_NUM_B2C(sbi, sbi->s_stripe);
+ i = EXT4_B2C(sbi, i);
+ while (i < EXT4_CLUSTERS_PER_GROUP(sb)) {
+ if (!mb_test_bit(i, bitmap)) {
+ max = mb_find_extent(e4b, i, stripe, &ex);
+ if (max >= stripe) {
+ ac->ac_found++;
+ ac->ac_cX_found[ac->ac_criteria]++;
+ ex.fe_logical = 0xDEADF00D; /* debug value */
+ ac->ac_b_ex = ex;
+ ext4_mb_use_best_found(ac, e4b);
+ break;
+ }
+ }
+ i += stripe;
+ }
+}
+
+static void __ext4_mb_scan_group(struct ext4_allocation_context *ac)
+{
+ bool is_stripe_aligned;
+ struct ext4_sb_info *sbi;
+ enum criteria cr = ac->ac_criteria;
+
+ ac->ac_groups_scanned++;
+ if (cr == CR_POWER2_ALIGNED)
+ return ext4_mb_simple_scan_group(ac, ac->ac_e4b);
+
+ sbi = EXT4_SB(ac->ac_sb);
+ is_stripe_aligned = false;
+ if ((sbi->s_stripe >= sbi->s_cluster_ratio) &&
+ !(ac->ac_g_ex.fe_len % EXT4_NUM_B2C(sbi, sbi->s_stripe)))
+ is_stripe_aligned = true;
+
+ if ((cr == CR_GOAL_LEN_FAST || cr == CR_BEST_AVAIL_LEN) &&
+ is_stripe_aligned)
+ ext4_mb_scan_aligned(ac, ac->ac_e4b);
+
+ if (ac->ac_status == AC_STATUS_CONTINUE)
+ ext4_mb_complex_scan_group(ac, ac->ac_e4b);
+}
+
+/*
+ * This is also called BEFORE we load the buddy bitmap.
+ * Returns either 1 or 0 indicating that the group is either suitable
+ * for the allocation or not.
+ */
+static bool ext4_mb_good_group(struct ext4_allocation_context *ac,
+ ext4_group_t group, enum criteria cr)
+{
+ ext4_grpblk_t free, fragments;
+ int flex_size = ext4_flex_bg_size(EXT4_SB(ac->ac_sb));
+ struct ext4_group_info *grp = ext4_get_group_info(ac->ac_sb, group);
+
+ BUG_ON(cr < CR_POWER2_ALIGNED || cr >= EXT4_MB_NUM_CRS);
+
+ if (unlikely(!grp || EXT4_MB_GRP_BBITMAP_CORRUPT(grp)))
+ return false;
+
+ free = grp->bb_free;
+ if (free == 0)
+ return false;
+
+ fragments = grp->bb_fragments;
+ if (fragments == 0)
+ return false;
+
+ switch (cr) {
+ case CR_POWER2_ALIGNED:
+ BUG_ON(ac->ac_2order == 0);
+
+ /* Avoid using the first bg of a flexgroup for data files */
+ if ((ac->ac_flags & EXT4_MB_HINT_DATA) &&
+ (flex_size >= EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME) &&
+ ((group % flex_size) == 0))
+ return false;
+
+ if (free < ac->ac_g_ex.fe_len)
+ return false;
+
+ if (ac->ac_2order >= MB_NUM_ORDERS(ac->ac_sb))
+ return true;
+
+ if (grp->bb_largest_free_order < ac->ac_2order)
+ return false;
+
+ return true;
+ case CR_GOAL_LEN_FAST:
+ case CR_BEST_AVAIL_LEN:
+ if ((free / fragments) >= ac->ac_g_ex.fe_len)
+ return true;
+ break;
+ case CR_GOAL_LEN_SLOW:
+ if (free >= ac->ac_g_ex.fe_len)
+ return true;
+ break;
+ case CR_ANY_FREE:
+ return true;
+ default:
+ BUG();
+ }
+
+ return false;
+}
+
+/*
+ * This could return negative error code if something goes wrong
+ * during ext4_mb_init_group(). This should not be called with
+ * ext4_lock_group() held.
+ *
+ * Note: because we are conditionally operating with the group lock in
+ * the EXT4_MB_STRICT_CHECK case, we need to fake out sparse in this
+ * function using __acquire and __release. This means we need to be
+ * super careful before messing with the error path handling via "goto
+ * out"!
+ */
+static int ext4_mb_good_group_nolock(struct ext4_allocation_context *ac,
+ ext4_group_t group, enum criteria cr)
+{
+ struct ext4_group_info *grp = ext4_get_group_info(ac->ac_sb, group);
+ struct super_block *sb = ac->ac_sb;
+ struct ext4_sb_info *sbi = EXT4_SB(sb);
+ bool should_lock = ac->ac_flags & EXT4_MB_STRICT_CHECK;
+ ext4_grpblk_t free;
+ int ret = 0;
+
+ if (!grp)
+ return -EFSCORRUPTED;
+ if (sbi->s_mb_stats)
+ atomic64_inc(&sbi->s_bal_cX_groups_considered[ac->ac_criteria]);
+ if (should_lock) {
+ ext4_lock_group(sb, group);
+ __release(ext4_group_lock_ptr(sb, group));
+ }
+ free = grp->bb_free;
+ if (free == 0)
+ goto out;
+ /*
+ * In all criterias except CR_ANY_FREE we try to avoid groups that
+ * can't possibly satisfy the full goal request due to insufficient
+ * free blocks.
+ */
+ if (cr < CR_ANY_FREE && free < ac->ac_g_ex.fe_len)
+ goto out;
+ if (unlikely(EXT4_MB_GRP_BBITMAP_CORRUPT(grp)))
+ goto out;
+ if (should_lock) {
+ __acquire(ext4_group_lock_ptr(sb, group));
+ ext4_unlock_group(sb, group);
+ }
+
+ /* We only do this if the grp has never been initialized */
+ if (unlikely(EXT4_MB_GRP_NEED_INIT(grp))) {
+ struct ext4_group_desc *gdp =
+ ext4_get_group_desc(sb, group, NULL);
+ int ret;
+
+ /*
+ * CR_POWER2_ALIGNED/CR_GOAL_LEN_FAST is a very optimistic
+ * search to find large good chunks almost for free. If buddy
+ * data is not ready, then this optimization makes no sense. But
+ * we never skip the first block group in a flex_bg, since this
+ * gets used for metadata block allocation, and we want to make
+ * sure we locate metadata blocks in the first block group in
+ * the flex_bg if possible.
+ */
+ if (!ext4_mb_cr_expensive(cr) &&
+ (!sbi->s_log_groups_per_flex ||
+ ((group & ((1 << sbi->s_log_groups_per_flex) - 1)) != 0)) &&
+ !(ext4_has_group_desc_csum(sb) &&
+ (gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT))))
+ return 0;
+ ret = ext4_mb_init_group(sb, group, GFP_NOFS);
+ if (ret)
+ return ret;
+ }
+
+ if (should_lock) {
+ ext4_lock_group(sb, group);
+ __release(ext4_group_lock_ptr(sb, group));
+ }
+ ret = ext4_mb_good_group(ac, group, cr);
+out:
+ if (should_lock) {
+ __acquire(ext4_group_lock_ptr(sb, group));
+ ext4_unlock_group(sb, group);
+ }
+ return ret;
+}
+
+/*
+ * Start prefetching @nr block bitmaps starting at @group.
+ * Return the next group which needs to be prefetched.
+ */
+ext4_group_t ext4_mb_prefetch(struct super_block *sb, ext4_group_t group,
+ unsigned int nr, int *cnt)
+{
+ ext4_group_t ngroups = ext4_get_groups_count(sb);
+ struct buffer_head *bh;
+ struct blk_plug plug;
+
+ blk_start_plug(&plug);
+ while (nr-- > 0) {
+ struct ext4_group_desc *gdp = ext4_get_group_desc(sb, group,
+ NULL);
+ struct ext4_group_info *grp = ext4_get_group_info(sb, group);
+
+ /*
+ * Prefetch block groups with free blocks; but don't
+ * bother if it is marked uninitialized on disk, since
+ * it won't require I/O to read. Also only try to
+ * prefetch once, so we avoid getblk() call, which can
+ * be expensive.
+ */
+ if (gdp && grp && !EXT4_MB_GRP_TEST_AND_SET_READ(grp) &&
+ EXT4_MB_GRP_NEED_INIT(grp) &&
+ ext4_free_group_clusters(sb, gdp) > 0 ) {
+ bh = ext4_read_block_bitmap_nowait(sb, group, true);
+ if (bh && !IS_ERR(bh)) {
+ if (!buffer_uptodate(bh) && cnt)
+ (*cnt)++;
+ brelse(bh);
+ }
+ }
+ if (++group >= ngroups)
+ group = 0;
+ }
+ blk_finish_plug(&plug);
+ return group;
+}
+
+/*
+ * Batch reads of the block allocation bitmaps to get
+ * multiple READs in flight; limit prefetching at inexpensive
+ * CR, otherwise mballoc can spend a lot of time loading
+ * imperfect groups
+ */
+static void ext4_mb_might_prefetch(struct ext4_allocation_context *ac,
+ ext4_group_t group)
+{
+ struct ext4_sb_info *sbi;
+
+ if (ac->ac_prefetch_grp != group)
+ return;
+
+ sbi = EXT4_SB(ac->ac_sb);
+ if (ext4_mb_cr_expensive(ac->ac_criteria) ||
+ ac->ac_prefetch_ios < sbi->s_mb_prefetch_limit) {
+ unsigned int nr = sbi->s_mb_prefetch;
+
+ if (ext4_has_feature_flex_bg(ac->ac_sb)) {
+ nr = 1 << sbi->s_log_groups_per_flex;
+ nr -= group & (nr - 1);
+ nr = umin(nr, sbi->s_mb_prefetch);
+ }
+
+ ac->ac_prefetch_nr = nr;
+ ac->ac_prefetch_grp = ext4_mb_prefetch(ac->ac_sb, group, nr,
+ &ac->ac_prefetch_ios);
+ }
+}
+
+/*
+ * Prefetching reads the block bitmap into the buffer cache; but we
+ * need to make sure that the buddy bitmap in the page cache has been
+ * initialized. Note that ext4_mb_init_group() will block if the I/O
+ * is not yet completed, or indeed if it was not initiated by
+ * ext4_mb_prefetch did not start the I/O.
+ *
+ * TODO: We should actually kick off the buddy bitmap setup in a work
+ * queue when the buffer I/O is completed, so that we don't block
+ * waiting for the block allocation bitmap read to finish when
+ * ext4_mb_prefetch_fini is called from ext4_mb_regular_allocator().
+ */
+void ext4_mb_prefetch_fini(struct super_block *sb, ext4_group_t group,
+ unsigned int nr)
+{
+ struct ext4_group_desc *gdp;
+ struct ext4_group_info *grp;
+
+ while (nr-- > 0) {
+ if (!group)
+ group = ext4_get_groups_count(sb);
+ group--;
+ gdp = ext4_get_group_desc(sb, group, NULL);
+ grp = ext4_get_group_info(sb, group);
+
+ if (grp && gdp && EXT4_MB_GRP_NEED_INIT(grp) &&
+ ext4_free_group_clusters(sb, gdp) > 0) {
+ if (ext4_mb_init_group(sb, group, GFP_NOFS))
+ break;
+ }
+ }
+}
+
+static int ext4_mb_scan_group(struct ext4_allocation_context *ac,
+ ext4_group_t group)
+{
+ int ret;
+ struct super_block *sb = ac->ac_sb;
+ enum criteria cr = ac->ac_criteria;
+
+ ext4_mb_might_prefetch(ac, group);
+
+ /* prevent unnecessary buddy loading. */
+ if (cr < CR_ANY_FREE && spin_is_locked(ext4_group_lock_ptr(sb, group)))
+ return 0;
+
+ /* This now checks without needing the buddy page */
+ ret = ext4_mb_good_group_nolock(ac, group, cr);
+ if (ret <= 0) {
+ if (!ac->ac_first_err)
+ ac->ac_first_err = ret;
+ return 0;
+ }
+
+ ret = ext4_mb_load_buddy(sb, group, ac->ac_e4b);
+ if (ret)
+ return ret;
+
+ /* skip busy group */
+ if (cr >= CR_ANY_FREE)
+ ext4_lock_group(sb, group);
+ else if (!ext4_try_lock_group(sb, group))
+ goto out_unload;
+
+ /* We need to check again after locking the block group. */
+ if (unlikely(!ext4_mb_good_group(ac, group, cr)))
+ goto out_unlock;
+
+ __ext4_mb_scan_group(ac);
+
+out_unlock:
+ ext4_unlock_group(sb, group);
+out_unload:
+ ext4_mb_unload_buddy(ac->ac_e4b);
+ return ret;
+}
+
+static noinline_for_stack int
+ext4_mb_regular_allocator(struct ext4_allocation_context *ac)
+{
+ ext4_group_t i;
+ int err = 0;
+ struct super_block *sb = ac->ac_sb;
+ struct ext4_sb_info *sbi = EXT4_SB(sb);
+ struct ext4_buddy e4b;
+
+ BUG_ON(ac->ac_status == AC_STATUS_FOUND);
+
+ /* first, try the goal */
+ err = ext4_mb_find_by_goal(ac, &e4b);
+ if (err || ac->ac_status == AC_STATUS_FOUND)
+ goto out;
+
+ if (unlikely(ac->ac_flags & EXT4_MB_HINT_GOAL_ONLY))
+ goto out;
+
+ /*
+ * ac->ac_2order is set only if the fe_len is a power of 2
+ * if ac->ac_2order is set we also set criteria to CR_POWER2_ALIGNED
+ * so that we try exact allocation using buddy.
+ */
+ i = fls(ac->ac_g_ex.fe_len);
+ ac->ac_2order = 0;
+ /*
+ * We search using buddy data only if the order of the request
+ * is greater than equal to the sbi_s_mb_order2_reqs
+ * You can tune it via /sys/fs/ext4/<partition>/mb_order2_req
+ * We also support searching for power-of-two requests only for
+ * requests upto maximum buddy size we have constructed.
+ */
+ if (i >= sbi->s_mb_order2_reqs && i <= MB_NUM_ORDERS(sb)) {
+ if (is_power_of_2(ac->ac_g_ex.fe_len))
+ ac->ac_2order = array_index_nospec(i - 1,
+ MB_NUM_ORDERS(sb));
+ }
+
+ /* if stream allocation is enabled, use global goal */
+ if (ac->ac_flags & EXT4_MB_STREAM_ALLOC) {
+ int hash = ac->ac_inode->i_ino % sbi->s_mb_nr_global_goals;
+
+ ac->ac_g_ex.fe_group = READ_ONCE(sbi->s_mb_last_groups[hash]);
+ ac->ac_g_ex.fe_start = -1;
+ ac->ac_flags &= ~EXT4_MB_HINT_TRY_GOAL;
+ }
+
+ /*
+ * Let's just scan groups to find more-less suitable blocks We
+ * start with CR_GOAL_LEN_FAST, unless it is power of 2
+ * aligned, in which case let's do that faster approach first.
+ */
+ ac->ac_criteria = CR_GOAL_LEN_FAST;
+ if (ac->ac_2order)
+ ac->ac_criteria = CR_POWER2_ALIGNED;
+
+ ac->ac_e4b = &e4b;
+ ac->ac_prefetch_ios = 0;
+ ac->ac_first_err = 0;
+repeat:
+ while (ac->ac_criteria < EXT4_MB_NUM_CRS) {
+ err = ext4_mb_scan_groups(ac);
+ if (err)
+ goto out;
+
+ if (ac->ac_status != AC_STATUS_CONTINUE)
+ break;
+ }
+
+ if (ac->ac_b_ex.fe_len > 0 && ac->ac_status != AC_STATUS_FOUND &&
+ !(ac->ac_flags & EXT4_MB_HINT_FIRST)) {
+ /*
+ * We've been searching too long. Let's try to allocate
+ * the best chunk we've found so far
+ */
+ ext4_mb_try_best_found(ac, &e4b);
+ if (ac->ac_status != AC_STATUS_FOUND) {
+ int lost;
+
+ /*
+ * Someone more lucky has already allocated it.
+ * The only thing we can do is just take first
+ * found block(s)
+ */
+ lost = atomic_inc_return(&sbi->s_mb_lost_chunks);
+ mb_debug(sb, "lost chunk, group: %u, start: %d, len: %d, lost: %d\n",
+ ac->ac_b_ex.fe_group, ac->ac_b_ex.fe_start,
+ ac->ac_b_ex.fe_len, lost);
+
+ ac->ac_b_ex.fe_group = 0;
+ ac->ac_b_ex.fe_start = 0;
+ ac->ac_b_ex.fe_len = 0;
+ ac->ac_status = AC_STATUS_CONTINUE;
+ ac->ac_flags |= EXT4_MB_HINT_FIRST;
+ ac->ac_criteria = CR_ANY_FREE;
+ goto repeat;
+ }
+ }
+
+ if (sbi->s_mb_stats && ac->ac_status == AC_STATUS_FOUND) {
+ atomic64_inc(&sbi->s_bal_cX_hits[ac->ac_criteria]);
+ if (ac->ac_flags & EXT4_MB_STREAM_ALLOC &&
+ ac->ac_b_ex.fe_group == ac->ac_g_ex.fe_group)
+ atomic_inc(&sbi->s_bal_stream_goals);
+ }
+out:
+ if (!err && ac->ac_status != AC_STATUS_FOUND && ac->ac_first_err)
+ err = ac->ac_first_err;
+
+ mb_debug(sb, "Best len %d, origin len %d, ac_status %u, ac_flags 0x%x, cr %d ret %d\n",
+ ac->ac_b_ex.fe_len, ac->ac_o_ex.fe_len, ac->ac_status,
+ ac->ac_flags, ac->ac_criteria, err);
+
+ if (ac->ac_prefetch_nr)
+ ext4_mb_prefetch_fini(sb, ac->ac_prefetch_grp, ac->ac_prefetch_nr);
+
+ return err;
+}
+
+static void *ext4_mb_seq_groups_start(struct seq_file *seq, loff_t *pos)
+{
+ struct super_block *sb = pde_data(file_inode(seq->file));
+ ext4_group_t group;
+
+ if (*pos < 0 || *pos >= ext4_get_groups_count(sb))
+ return NULL;
+ group = *pos + 1;
+ return (void *) ((unsigned long) group);
+}
+
+static void *ext4_mb_seq_groups_next(struct seq_file *seq, void *v, loff_t *pos)
+{
+ struct super_block *sb = pde_data(file_inode(seq->file));
+ ext4_group_t group;
+
+ ++*pos;
+ if (*pos < 0 || *pos >= ext4_get_groups_count(sb))
+ return NULL;
+ group = *pos + 1;
+ return (void *) ((unsigned long) group);
+}
+
+static int ext4_mb_seq_groups_show(struct seq_file *seq, void *v)
+{
+ struct super_block *sb = pde_data(file_inode(seq->file));
+ ext4_group_t group = (ext4_group_t) ((unsigned long) v);
+ int i, err;
+ char nbuf[16];
+ struct ext4_buddy e4b;
+ struct ext4_group_info *grinfo;
+ unsigned char blocksize_bits = min_t(unsigned char,
+ sb->s_blocksize_bits,
+ EXT4_MAX_BLOCK_LOG_SIZE);
+ DEFINE_RAW_FLEX(struct ext4_group_info, sg, bb_counters,
+ EXT4_MAX_BLOCK_LOG_SIZE + 2);
+
+ group--;
+ if (group == 0)
+ seq_puts(seq, "#group: free frags first ["
+ " 2^0 2^1 2^2 2^3 2^4 2^5 2^6 "
+ " 2^7 2^8 2^9 2^10 2^11 2^12 2^13 ]\n");
+
+ i = (blocksize_bits + 2) * sizeof(sg->bb_counters[0]) +
+ sizeof(struct ext4_group_info);
+
+ grinfo = ext4_get_group_info(sb, group);
+ if (!grinfo)
+ return 0;
+ /* Load the group info in memory only if not already loaded. */
+ if (unlikely(EXT4_MB_GRP_NEED_INIT(grinfo))) {
+ err = ext4_mb_load_buddy(sb, group, &e4b);
+ if (err) {
+ seq_printf(seq, "#%-5u: %s\n", group, ext4_decode_error(NULL, err, nbuf));
+ return 0;
+ }
+ ext4_mb_unload_buddy(&e4b);
+ }
+
+ /*
+ * We care only about free space counters in the group info and
+ * these are safe to access even after the buddy has been unloaded
+ */
+ memcpy(sg, grinfo, i);
+ seq_printf(seq, "#%-5u: %-5u %-5u %-5u [", group, sg->bb_free,
+ sg->bb_fragments, sg->bb_first_free);
+ for (i = 0; i <= 13; i++)
+ seq_printf(seq, " %-5u", i <= blocksize_bits + 1 ?
+ sg->bb_counters[i] : 0);
+ seq_puts(seq, " ]");
+ if (EXT4_MB_GRP_BBITMAP_CORRUPT(sg))
+ seq_puts(seq, " Block bitmap corrupted!");
+ seq_putc(seq, '\n');
+ return 0;
+}
+
+static void ext4_mb_seq_groups_stop(struct seq_file *seq, void *v)
+{
+}
+
+const struct seq_operations ext4_mb_seq_groups_ops = {
+ .start = ext4_mb_seq_groups_start,
+ .next = ext4_mb_seq_groups_next,
+ .stop = ext4_mb_seq_groups_stop,
+ .show = ext4_mb_seq_groups_show,
+};
+
+int ext4_seq_mb_stats_show(struct seq_file *seq, void *offset)
+{
+ struct super_block *sb = seq->private;
+ struct ext4_sb_info *sbi = EXT4_SB(sb);
+
+ seq_puts(seq, "mballoc:\n");
+ if (!sbi->s_mb_stats) {
+ seq_puts(seq, "\tmb stats collection turned off.\n");
+ seq_puts(
+ seq,
+ "\tTo enable, please write \"1\" to sysfs file mb_stats.\n");
+ return 0;
+ }
+ seq_printf(seq, "\treqs: %u\n", atomic_read(&sbi->s_bal_reqs));
+ seq_printf(seq, "\tsuccess: %u\n", atomic_read(&sbi->s_bal_success));
+
+ seq_printf(seq, "\tgroups_scanned: %u\n",
+ atomic_read(&sbi->s_bal_groups_scanned));
+
+ /* CR_POWER2_ALIGNED stats */
+ seq_puts(seq, "\tcr_p2_aligned_stats:\n");
+ seq_printf(seq, "\t\thits: %llu\n",
+ atomic64_read(&sbi->s_bal_cX_hits[CR_POWER2_ALIGNED]));
+ seq_printf(
+ seq, "\t\tgroups_considered: %llu\n",
+ atomic64_read(
+ &sbi->s_bal_cX_groups_considered[CR_POWER2_ALIGNED]));
+ seq_printf(seq, "\t\textents_scanned: %u\n",
+ atomic_read(&sbi->s_bal_cX_ex_scanned[CR_POWER2_ALIGNED]));
+ seq_printf(seq, "\t\tuseless_loops: %llu\n",
+ atomic64_read(&sbi->s_bal_cX_failed[CR_POWER2_ALIGNED]));
+
+ /* CR_GOAL_LEN_FAST stats */
+ seq_puts(seq, "\tcr_goal_fast_stats:\n");
+ seq_printf(seq, "\t\thits: %llu\n",
+ atomic64_read(&sbi->s_bal_cX_hits[CR_GOAL_LEN_FAST]));
+ seq_printf(seq, "\t\tgroups_considered: %llu\n",
+ atomic64_read(
+ &sbi->s_bal_cX_groups_considered[CR_GOAL_LEN_FAST]));
+ seq_printf(seq, "\t\textents_scanned: %u\n",
+ atomic_read(&sbi->s_bal_cX_ex_scanned[CR_GOAL_LEN_FAST]));
+ seq_printf(seq, "\t\tuseless_loops: %llu\n",
+ atomic64_read(&sbi->s_bal_cX_failed[CR_GOAL_LEN_FAST]));
+
+ /* CR_BEST_AVAIL_LEN stats */
+ seq_puts(seq, "\tcr_best_avail_stats:\n");
+ seq_printf(seq, "\t\thits: %llu\n",
+ atomic64_read(&sbi->s_bal_cX_hits[CR_BEST_AVAIL_LEN]));
+ seq_printf(
+ seq, "\t\tgroups_considered: %llu\n",
+ atomic64_read(
+ &sbi->s_bal_cX_groups_considered[CR_BEST_AVAIL_LEN]));
+ seq_printf(seq, "\t\textents_scanned: %u\n",
+ atomic_read(&sbi->s_bal_cX_ex_scanned[CR_BEST_AVAIL_LEN]));
+ seq_printf(seq, "\t\tuseless_loops: %llu\n",
+ atomic64_read(&sbi->s_bal_cX_failed[CR_BEST_AVAIL_LEN]));
+
+ /* CR_GOAL_LEN_SLOW stats */
+ seq_puts(seq, "\tcr_goal_slow_stats:\n");
+ seq_printf(seq, "\t\thits: %llu\n",
+ atomic64_read(&sbi->s_bal_cX_hits[CR_GOAL_LEN_SLOW]));
+ seq_printf(seq, "\t\tgroups_considered: %llu\n",
+ atomic64_read(
+ &sbi->s_bal_cX_groups_considered[CR_GOAL_LEN_SLOW]));
+ seq_printf(seq, "\t\textents_scanned: %u\n",
+ atomic_read(&sbi->s_bal_cX_ex_scanned[CR_GOAL_LEN_SLOW]));
+ seq_printf(seq, "\t\tuseless_loops: %llu\n",
+ atomic64_read(&sbi->s_bal_cX_failed[CR_GOAL_LEN_SLOW]));
+
+ /* CR_ANY_FREE stats */
+ seq_puts(seq, "\tcr_any_free_stats:\n");
+ seq_printf(seq, "\t\thits: %llu\n",
+ atomic64_read(&sbi->s_bal_cX_hits[CR_ANY_FREE]));
+ seq_printf(
+ seq, "\t\tgroups_considered: %llu\n",
+ atomic64_read(&sbi->s_bal_cX_groups_considered[CR_ANY_FREE]));
+ seq_printf(seq, "\t\textents_scanned: %u\n",
+ atomic_read(&sbi->s_bal_cX_ex_scanned[CR_ANY_FREE]));
+ seq_printf(seq, "\t\tuseless_loops: %llu\n",
+ atomic64_read(&sbi->s_bal_cX_failed[CR_ANY_FREE]));
+
+ /* Aggregates */
+ seq_printf(seq, "\textents_scanned: %u\n",
+ atomic_read(&sbi->s_bal_ex_scanned));
+ seq_printf(seq, "\t\tgoal_hits: %u\n", atomic_read(&sbi->s_bal_goals));
+ seq_printf(seq, "\t\tstream_goal_hits: %u\n",
+ atomic_read(&sbi->s_bal_stream_goals));
+ seq_printf(seq, "\t\tlen_goal_hits: %u\n",
+ atomic_read(&sbi->s_bal_len_goals));
+ seq_printf(seq, "\t\t2^n_hits: %u\n", atomic_read(&sbi->s_bal_2orders));
+ seq_printf(seq, "\t\tbreaks: %u\n", atomic_read(&sbi->s_bal_breaks));
+ seq_printf(seq, "\t\tlost: %u\n", atomic_read(&sbi->s_mb_lost_chunks));
+ seq_printf(seq, "\tbuddies_generated: %u/%u\n",
+ atomic_read(&sbi->s_mb_buddies_generated),
+ ext4_get_groups_count(sb));
+ seq_printf(seq, "\tbuddies_time_used: %llu\n",
+ atomic64_read(&sbi->s_mb_generation_time));
+ seq_printf(seq, "\tpreallocated: %u\n",
+ atomic_read(&sbi->s_mb_preallocated));
+ seq_printf(seq, "\tdiscarded: %u\n", atomic_read(&sbi->s_mb_discarded));
+ return 0;
+}
+
+static void *ext4_mb_seq_structs_summary_start(struct seq_file *seq, loff_t *pos)
+{
+ struct super_block *sb = pde_data(file_inode(seq->file));
+ unsigned long position;
+
+ if (*pos < 0 || *pos >= 2*MB_NUM_ORDERS(sb))
+ return NULL;
+ position = *pos + 1;
+ return (void *) ((unsigned long) position);
+}
+
+static void *ext4_mb_seq_structs_summary_next(struct seq_file *seq, void *v, loff_t *pos)
+{
+ struct super_block *sb = pde_data(file_inode(seq->file));
+ unsigned long position;
+
+ ++*pos;
+ if (*pos < 0 || *pos >= 2*MB_NUM_ORDERS(sb))
+ return NULL;
+ position = *pos + 1;
+ return (void *) ((unsigned long) position);
+}
+
+static int ext4_mb_seq_structs_summary_show(struct seq_file *seq, void *v)
+{
+ struct super_block *sb = pde_data(file_inode(seq->file));
+ struct ext4_sb_info *sbi = EXT4_SB(sb);
+ unsigned long position = ((unsigned long) v);
+ struct ext4_group_info *grp;
+ unsigned int count;
+ unsigned long idx;
+
+ position--;
+ if (position >= MB_NUM_ORDERS(sb)) {
+ position -= MB_NUM_ORDERS(sb);
+ if (position == 0)
+ seq_puts(seq, "avg_fragment_size_lists:\n");
+
+ count = 0;
+ xa_for_each(&sbi->s_mb_avg_fragment_size[position], idx, grp)
+ count++;
+ seq_printf(seq, "\tlist_order_%u_groups: %u\n",
+ (unsigned int)position, count);
+ return 0;
+ }
+
+ if (position == 0) {
+ seq_printf(seq, "optimize_scan: %d\n",
+ test_opt2(sb, MB_OPTIMIZE_SCAN) ? 1 : 0);
+ seq_puts(seq, "max_free_order_lists:\n");
+ }
+ count = 0;
+ xa_for_each(&sbi->s_mb_largest_free_orders[position], idx, grp)
+ count++;
+ seq_printf(seq, "\tlist_order_%u_groups: %u\n",
+ (unsigned int)position, count);
+
+ return 0;
+}
+
+static void ext4_mb_seq_structs_summary_stop(struct seq_file *seq, void *v)
+{
+}
+
+const struct seq_operations ext4_mb_seq_structs_summary_ops = {
+ .start = ext4_mb_seq_structs_summary_start,
+ .next = ext4_mb_seq_structs_summary_next,
+ .stop = ext4_mb_seq_structs_summary_stop,
+ .show = ext4_mb_seq_structs_summary_show,
+};
+
+static struct kmem_cache *get_groupinfo_cache(int blocksize_bits)
+{
+ int cache_index = blocksize_bits - EXT4_MIN_BLOCK_LOG_SIZE;
+ struct kmem_cache *cachep = ext4_groupinfo_caches[cache_index];
+
+ BUG_ON(!cachep);
+ return cachep;
+}
+
+/*
+ * Allocate the top-level s_group_info array for the specified number
+ * of groups
+ */
+int ext4_mb_alloc_groupinfo(struct super_block *sb, ext4_group_t ngroups)
+{
+ struct ext4_sb_info *sbi = EXT4_SB(sb);
+ unsigned size;
+ struct ext4_group_info ***old_groupinfo, ***new_groupinfo;
+
+ size = (ngroups + EXT4_DESC_PER_BLOCK(sb) - 1) >>
+ EXT4_DESC_PER_BLOCK_BITS(sb);
+ if (size <= sbi->s_group_info_size)
+ return 0;
+
+ size = roundup_pow_of_two(sizeof(*sbi->s_group_info) * size);
+ new_groupinfo = kvzalloc(size, GFP_KERNEL);
+ if (!new_groupinfo) {
+ ext4_msg(sb, KERN_ERR, "can't allocate buddy meta group");
+ return -ENOMEM;
+ }
+ rcu_read_lock();
+ old_groupinfo = rcu_dereference(sbi->s_group_info);
+ if (old_groupinfo)
+ memcpy(new_groupinfo, old_groupinfo,
+ sbi->s_group_info_size * sizeof(*sbi->s_group_info));
+ rcu_read_unlock();
+ rcu_assign_pointer(sbi->s_group_info, new_groupinfo);
+ sbi->s_group_info_size = size / sizeof(*sbi->s_group_info);
+ if (old_groupinfo)
+ ext4_kvfree_array_rcu(old_groupinfo);
+ ext4_debug("allocated s_groupinfo array for %d meta_bg's\n",
+ sbi->s_group_info_size);
+ return 0;
+}
+
+/* Create and initialize ext4_group_info data for the given group. */
+int ext4_mb_add_groupinfo(struct super_block *sb, ext4_group_t group,
+ struct ext4_group_desc *desc)
+{
+ int i;
+ int metalen = 0;
+ int idx = group >> EXT4_DESC_PER_BLOCK_BITS(sb);
+ struct ext4_sb_info *sbi = EXT4_SB(sb);
+ struct ext4_group_info **meta_group_info;
+ struct kmem_cache *cachep = get_groupinfo_cache(sb->s_blocksize_bits);
+
+ /*
+ * First check if this group is the first of a reserved block.
+ * If it's true, we have to allocate a new table of pointers
+ * to ext4_group_info structures
+ */
+ if (group % EXT4_DESC_PER_BLOCK(sb) == 0) {
+ metalen = sizeof(*meta_group_info) <<
+ EXT4_DESC_PER_BLOCK_BITS(sb);
+ meta_group_info = kmalloc(metalen, GFP_NOFS);
+ if (meta_group_info == NULL) {
+ ext4_msg(sb, KERN_ERR, "can't allocate mem "
+ "for a buddy group");
+ return -ENOMEM;
+ }
+ rcu_read_lock();
+ rcu_dereference(sbi->s_group_info)[idx] = meta_group_info;
+ rcu_read_unlock();
+ }
+
+ meta_group_info = sbi_array_rcu_deref(sbi, s_group_info, idx);
+ i = group & (EXT4_DESC_PER_BLOCK(sb) - 1);
+
+ meta_group_info[i] = kmem_cache_zalloc(cachep, GFP_NOFS);
+ if (meta_group_info[i] == NULL) {
+ ext4_msg(sb, KERN_ERR, "can't allocate buddy mem");
+ goto exit_group_info;
+ }
+ set_bit(EXT4_GROUP_INFO_NEED_INIT_BIT,
+ &(meta_group_info[i]->bb_state));
+
+ /*
+ * initialize bb_free to be able to skip
+ * empty groups without initialization
+ */
+ if (ext4_has_group_desc_csum(sb) &&
+ (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT))) {
+ meta_group_info[i]->bb_free =
+ ext4_free_clusters_after_init(sb, group, desc);
+ } else {
+ meta_group_info[i]->bb_free =
+ ext4_free_group_clusters(sb, desc);
+ }
+
+ INIT_LIST_HEAD(&meta_group_info[i]->bb_prealloc_list);
+ init_rwsem(&meta_group_info[i]->alloc_sem);
+ meta_group_info[i]->bb_free_root = RB_ROOT;
+ meta_group_info[i]->bb_largest_free_order = -1; /* uninit */
+ meta_group_info[i]->bb_avg_fragment_size_order = -1; /* uninit */
+ meta_group_info[i]->bb_group = group;
+
+ mb_group_bb_bitmap_alloc(sb, meta_group_info[i], group);
+ return 0;
+
+exit_group_info:
+ /* If a meta_group_info table has been allocated, release it now */
+ if (group % EXT4_DESC_PER_BLOCK(sb) == 0) {
+ struct ext4_group_info ***group_info;
+
+ rcu_read_lock();
+ group_info = rcu_dereference(sbi->s_group_info);
+ kfree(group_info[idx]);
+ group_info[idx] = NULL;
+ rcu_read_unlock();
+ }
+ return -ENOMEM;
+} /* ext4_mb_add_groupinfo */
+
+static int ext4_mb_init_backend(struct super_block *sb)
+{
+ ext4_group_t ngroups = ext4_get_groups_count(sb);
+ ext4_group_t i;
+ struct ext4_sb_info *sbi = EXT4_SB(sb);
+ int err;
+ struct ext4_group_desc *desc;
+ struct ext4_group_info ***group_info;
+ struct kmem_cache *cachep;
+
+ err = ext4_mb_alloc_groupinfo(sb, ngroups);
+ if (err)
+ return err;
+
+ sbi->s_buddy_cache = new_inode(sb);
+ if (sbi->s_buddy_cache == NULL) {
+ ext4_msg(sb, KERN_ERR, "can't get new inode");
+ goto err_freesgi;
+ }
+ /* To avoid potentially colliding with an valid on-disk inode number,
+ * use EXT4_BAD_INO for the buddy cache inode number. This inode is
+ * not in the inode hash, so it should never be found by iget(), but
+ * this will avoid confusion if it ever shows up during debugging. */
+ sbi->s_buddy_cache->i_ino = EXT4_BAD_INO;
+ EXT4_I(sbi->s_buddy_cache)->i_disksize = 0;
+ for (i = 0; i < ngroups; i++) {
+ cond_resched();
+ desc = ext4_get_group_desc(sb, i, NULL);
+ if (desc == NULL) {
+ ext4_msg(sb, KERN_ERR, "can't read descriptor %u", i);
+ goto err_freebuddy;
+ }
+ if (ext4_mb_add_groupinfo(sb, i, desc) != 0)
+ goto err_freebuddy;
+ }
+
+ if (ext4_has_feature_flex_bg(sb)) {
+ /* a single flex group is supposed to be read by a single IO.
+ * 2 ^ s_log_groups_per_flex != UINT_MAX as s_mb_prefetch is
+ * unsigned integer, so the maximum shift is 32.
+ */
+ if (sbi->s_es->s_log_groups_per_flex >= 32) {
+ ext4_msg(sb, KERN_ERR, "too many log groups per flexible block group");
+ goto err_freebuddy;
+ }
+ sbi->s_mb_prefetch = min_t(uint, 1 << sbi->s_es->s_log_groups_per_flex,
+ BLK_MAX_SEGMENT_SIZE >> (sb->s_blocksize_bits - 9));
+ sbi->s_mb_prefetch *= 8; /* 8 prefetch IOs in flight at most */
+ } else {
+ sbi->s_mb_prefetch = 32;
+ }
+ if (sbi->s_mb_prefetch > ext4_get_groups_count(sb))
+ sbi->s_mb_prefetch = ext4_get_groups_count(sb);
+ /*
+ * now many real IOs to prefetch within a single allocation at
+ * CR_POWER2_ALIGNED. Given CR_POWER2_ALIGNED is an CPU-related
+ * optimization we shouldn't try to load too many groups, at some point
+ * we should start to use what we've got in memory.
+ * with an average random access time 5ms, it'd take a second to get
+ * 200 groups (* N with flex_bg), so let's make this limit 4
+ */
+ sbi->s_mb_prefetch_limit = sbi->s_mb_prefetch * 4;
+ if (sbi->s_mb_prefetch_limit > ext4_get_groups_count(sb))
+ sbi->s_mb_prefetch_limit = ext4_get_groups_count(sb);
+
+ return 0;
+
+err_freebuddy:
+ cachep = get_groupinfo_cache(sb->s_blocksize_bits);
+ while (i-- > 0) {
+ struct ext4_group_info *grp = ext4_get_group_info(sb, i);
+
+ if (grp)
+ kmem_cache_free(cachep, grp);
+ }
+ i = sbi->s_group_info_size;
+ rcu_read_lock();
+ group_info = rcu_dereference(sbi->s_group_info);
+ while (i-- > 0)
+ kfree(group_info[i]);
+ rcu_read_unlock();
+ iput(sbi->s_buddy_cache);
+err_freesgi:
+ rcu_read_lock();
+ kvfree(rcu_dereference(sbi->s_group_info));
+ rcu_read_unlock();
+ return -ENOMEM;
+}
+
+static void ext4_groupinfo_destroy_slabs(void)
+{
+ int i;
+
+ for (i = 0; i < NR_GRPINFO_CACHES; i++) {
+ kmem_cache_destroy(ext4_groupinfo_caches[i]);
+ ext4_groupinfo_caches[i] = NULL;
+ }
+}
+
+static int ext4_groupinfo_create_slab(size_t size)
+{
+ static DEFINE_MUTEX(ext4_grpinfo_slab_create_mutex);
+ int slab_size;
+ int blocksize_bits = order_base_2(size);
+ int cache_index = blocksize_bits - EXT4_MIN_BLOCK_LOG_SIZE;
+ struct kmem_cache *cachep;
+
+ if (cache_index >= NR_GRPINFO_CACHES)
+ return -EINVAL;
+
+ if (unlikely(cache_index < 0))
+ cache_index = 0;
+
+ mutex_lock(&ext4_grpinfo_slab_create_mutex);
+ if (ext4_groupinfo_caches[cache_index]) {
+ mutex_unlock(&ext4_grpinfo_slab_create_mutex);
+ return 0; /* Already created */
+ }
+
+ slab_size = offsetof(struct ext4_group_info,
+ bb_counters[blocksize_bits + 2]);
+
+ cachep = kmem_cache_create(ext4_groupinfo_slab_names[cache_index],
+ slab_size, 0, SLAB_RECLAIM_ACCOUNT,
+ NULL);
+
+ ext4_groupinfo_caches[cache_index] = cachep;
+
+ mutex_unlock(&ext4_grpinfo_slab_create_mutex);
+ if (!cachep) {
+ printk(KERN_EMERG
+ "EXT4-fs: no memory for groupinfo slab cache\n");
+ return -ENOMEM;
+ }
+
+ return 0;
+}
+
+static void ext4_discard_work(struct work_struct *work)
+{
+ struct ext4_sb_info *sbi = container_of(work,
+ struct ext4_sb_info, s_discard_work);
+ struct super_block *sb = sbi->s_sb;
+ struct ext4_free_data *fd, *nfd;
+ struct ext4_buddy e4b;
+ LIST_HEAD(discard_list);
+ ext4_group_t grp, load_grp;
+ int err = 0;
+
+ spin_lock(&sbi->s_md_lock);
+ list_splice_init(&sbi->s_discard_list, &discard_list);
+ spin_unlock(&sbi->s_md_lock);
+
+ load_grp = UINT_MAX;
+ list_for_each_entry_safe(fd, nfd, &discard_list, efd_list) {
+ /*
+ * If filesystem is umounting or no memory or suffering
+ * from no space, give up the discard
+ */
+ if ((sb->s_flags & SB_ACTIVE) && !err &&
+ !atomic_read(&sbi->s_retry_alloc_pending)) {
+ grp = fd->efd_group;
+ if (grp != load_grp) {
+ if (load_grp != UINT_MAX)
+ ext4_mb_unload_buddy(&e4b);
+
+ err = ext4_mb_load_buddy(sb, grp, &e4b);
+ if (err) {
+ kmem_cache_free(ext4_free_data_cachep, fd);
+ load_grp = UINT_MAX;
+ continue;
+ } else {
+ load_grp = grp;
+ }
+ }
+
+ ext4_lock_group(sb, grp);
+ ext4_try_to_trim_range(sb, &e4b, fd->efd_start_cluster,
+ fd->efd_start_cluster + fd->efd_count - 1, 1);
+ ext4_unlock_group(sb, grp);
+ }
+ kmem_cache_free(ext4_free_data_cachep, fd);
+ }
+
+ if (load_grp != UINT_MAX)
+ ext4_mb_unload_buddy(&e4b);
+}
+
+static inline void ext4_mb_avg_fragment_size_destroy(struct ext4_sb_info *sbi)
+{
+ if (!sbi->s_mb_avg_fragment_size)
+ return;
+
+ for (int i = 0; i < MB_NUM_ORDERS(sbi->s_sb); i++)
+ xa_destroy(&sbi->s_mb_avg_fragment_size[i]);
+
+ kfree(sbi->s_mb_avg_fragment_size);
+ sbi->s_mb_avg_fragment_size = NULL;
+}
+
+static inline void ext4_mb_largest_free_orders_destroy(struct ext4_sb_info *sbi)
+{
+ if (!sbi->s_mb_largest_free_orders)
+ return;
+
+ for (int i = 0; i < MB_NUM_ORDERS(sbi->s_sb); i++)
+ xa_destroy(&sbi->s_mb_largest_free_orders[i]);
+
+ kfree(sbi->s_mb_largest_free_orders);
+ sbi->s_mb_largest_free_orders = NULL;
+}
+
+int ext4_mb_init(struct super_block *sb)
+{
+ struct ext4_sb_info *sbi = EXT4_SB(sb);
+ unsigned i, j;
+ unsigned offset, offset_incr;
+ unsigned max;
+ int ret;
+
+ i = MB_NUM_ORDERS(sb) * sizeof(*sbi->s_mb_offsets);
+
+ sbi->s_mb_offsets = kmalloc(i, GFP_KERNEL);
+ if (sbi->s_mb_offsets == NULL) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ i = MB_NUM_ORDERS(sb) * sizeof(*sbi->s_mb_maxs);
+ sbi->s_mb_maxs = kmalloc(i, GFP_KERNEL);
+ if (sbi->s_mb_maxs == NULL) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ ret = ext4_groupinfo_create_slab(sb->s_blocksize);
+ if (ret < 0)
+ goto out;
+
+ /* order 0 is regular bitmap */
+ sbi->s_mb_maxs[0] = sb->s_blocksize << 3;
+ sbi->s_mb_offsets[0] = 0;
+
+ i = 1;
+ offset = 0;
+ offset_incr = 1 << (sb->s_blocksize_bits - 1);
+ max = sb->s_blocksize << 2;
+ do {
+ sbi->s_mb_offsets[i] = offset;
+ sbi->s_mb_maxs[i] = max;
+ offset += offset_incr;
+ offset_incr = offset_incr >> 1;
+ max = max >> 1;
+ i++;
+ } while (i < MB_NUM_ORDERS(sb));
+
+ sbi->s_mb_avg_fragment_size =
+ kmalloc_array(MB_NUM_ORDERS(sb), sizeof(struct xarray),
+ GFP_KERNEL);
+ if (!sbi->s_mb_avg_fragment_size) {
+ ret = -ENOMEM;
+ goto out;
+ }
+ for (i = 0; i < MB_NUM_ORDERS(sb); i++)
+ xa_init(&sbi->s_mb_avg_fragment_size[i]);
+
+ sbi->s_mb_largest_free_orders =
+ kmalloc_array(MB_NUM_ORDERS(sb), sizeof(struct xarray),
+ GFP_KERNEL);
+ if (!sbi->s_mb_largest_free_orders) {
+ ret = -ENOMEM;
+ goto out;
+ }
+ for (i = 0; i < MB_NUM_ORDERS(sb); i++)
+ xa_init(&sbi->s_mb_largest_free_orders[i]);
+
+ spin_lock_init(&sbi->s_md_lock);
+ atomic_set(&sbi->s_mb_free_pending, 0);
+ INIT_LIST_HEAD(&sbi->s_freed_data_list[0]);
+ INIT_LIST_HEAD(&sbi->s_freed_data_list[1]);
+ INIT_LIST_HEAD(&sbi->s_discard_list);
+ INIT_WORK(&sbi->s_discard_work, ext4_discard_work);
+ atomic_set(&sbi->s_retry_alloc_pending, 0);
+
+ sbi->s_mb_max_to_scan = MB_DEFAULT_MAX_TO_SCAN;
+ sbi->s_mb_min_to_scan = MB_DEFAULT_MIN_TO_SCAN;
+ sbi->s_mb_stats = MB_DEFAULT_STATS;
+ sbi->s_mb_stream_request = MB_DEFAULT_STREAM_THRESHOLD;
+ sbi->s_mb_order2_reqs = MB_DEFAULT_ORDER2_REQS;
+ sbi->s_mb_best_avail_max_trim_order = MB_DEFAULT_BEST_AVAIL_TRIM_ORDER;
+
+ /*
+ * The default group preallocation is 512, which for 4k block
+ * sizes translates to 2 megabytes. However for bigalloc file
+ * systems, this is probably too big (i.e, if the cluster size
+ * is 1 megabyte, then group preallocation size becomes half a
+ * gigabyte!). As a default, we will keep a two megabyte
+ * group pralloc size for cluster sizes up to 64k, and after
+ * that, we will force a minimum group preallocation size of
+ * 32 clusters. This translates to 8 megs when the cluster
+ * size is 256k, and 32 megs when the cluster size is 1 meg,
+ * which seems reasonable as a default.
+ */
+ sbi->s_mb_group_prealloc = max(MB_DEFAULT_GROUP_PREALLOC >>
+ sbi->s_cluster_bits, 32);
+ /*
+ * If there is a s_stripe > 1, then we set the s_mb_group_prealloc
+ * to the lowest multiple of s_stripe which is bigger than
+ * the s_mb_group_prealloc as determined above. We want
+ * the preallocation size to be an exact multiple of the
+ * RAID stripe size so that preallocations don't fragment
+ * the stripes.
+ */
+ if (sbi->s_stripe > 1) {
+ sbi->s_mb_group_prealloc = roundup(
+ sbi->s_mb_group_prealloc, EXT4_NUM_B2C(sbi, sbi->s_stripe));
+ }
+
+ sbi->s_mb_nr_global_goals = umin(num_possible_cpus(),
+ DIV_ROUND_UP(sbi->s_groups_count, 4));
+ sbi->s_mb_last_groups = kcalloc(sbi->s_mb_nr_global_goals,
+ sizeof(ext4_group_t), GFP_KERNEL);
+ if (sbi->s_mb_last_groups == NULL) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ sbi->s_locality_groups = alloc_percpu(struct ext4_locality_group);
+ if (sbi->s_locality_groups == NULL) {
+ ret = -ENOMEM;
+ goto out_free_last_groups;
+ }
+ for_each_possible_cpu(i) {
+ struct ext4_locality_group *lg;
+ lg = per_cpu_ptr(sbi->s_locality_groups, i);
+ mutex_init(&lg->lg_mutex);
+ for (j = 0; j < PREALLOC_TB_SIZE; j++)
+ INIT_LIST_HEAD(&lg->lg_prealloc_list[j]);
+ spin_lock_init(&lg->lg_prealloc_lock);
+ }
+
+ if (bdev_nonrot(sb->s_bdev))
+ sbi->s_mb_max_linear_groups = 0;
+ else
+ sbi->s_mb_max_linear_groups = MB_DEFAULT_LINEAR_LIMIT;
+ /* init file for buddy data */
+ ret = ext4_mb_init_backend(sb);
+ if (ret != 0)
+ goto out_free_locality_groups;
+
+ return 0;
+
+out_free_locality_groups:
+ free_percpu(sbi->s_locality_groups);
+ sbi->s_locality_groups = NULL;
+out_free_last_groups:
+ kfree(sbi->s_mb_last_groups);
+ sbi->s_mb_last_groups = NULL;
+out:
+ ext4_mb_avg_fragment_size_destroy(sbi);
+ ext4_mb_largest_free_orders_destroy(sbi);
+ kfree(sbi->s_mb_offsets);
+ sbi->s_mb_offsets = NULL;
+ kfree(sbi->s_mb_maxs);
+ sbi->s_mb_maxs = NULL;
+ return ret;
+}
+
+/* need to called with the ext4 group lock held */
+static int ext4_mb_cleanup_pa(struct ext4_group_info *grp)
+{
+ struct ext4_prealloc_space *pa;
+ struct list_head *cur, *tmp;
+ int count = 0;
+
+ list_for_each_safe(cur, tmp, &grp->bb_prealloc_list) {
+ pa = list_entry(cur, struct ext4_prealloc_space, pa_group_list);
+ list_del(&pa->pa_group_list);
+ count++;
+ kmem_cache_free(ext4_pspace_cachep, pa);
+ }
+ return count;
+}
+
+void ext4_mb_release(struct super_block *sb)
+{
+ ext4_group_t ngroups = ext4_get_groups_count(sb);
+ ext4_group_t i;
+ int num_meta_group_infos;
+ struct ext4_group_info *grinfo, ***group_info;
+ struct ext4_sb_info *sbi = EXT4_SB(sb);
+ struct kmem_cache *cachep = get_groupinfo_cache(sb->s_blocksize_bits);
+ int count;
+
+ if (test_opt(sb, DISCARD)) {
+ /*
+ * wait the discard work to drain all of ext4_free_data
+ */
+ flush_work(&sbi->s_discard_work);
+ WARN_ON_ONCE(!list_empty(&sbi->s_discard_list));
+ }
+
+ if (sbi->s_group_info) {
+ for (i = 0; i < ngroups; i++) {
+ cond_resched();
+ grinfo = ext4_get_group_info(sb, i);
+ if (!grinfo)
+ continue;
+ mb_group_bb_bitmap_free(grinfo);
+ ext4_lock_group(sb, i);
+ count = ext4_mb_cleanup_pa(grinfo);
+ if (count)
+ mb_debug(sb, "mballoc: %d PAs left\n",
+ count);
+ ext4_unlock_group(sb, i);
+ kmem_cache_free(cachep, grinfo);
+ }
+ num_meta_group_infos = (ngroups +
+ EXT4_DESC_PER_BLOCK(sb) - 1) >>
+ EXT4_DESC_PER_BLOCK_BITS(sb);
+ rcu_read_lock();
+ group_info = rcu_dereference(sbi->s_group_info);
+ for (i = 0; i < num_meta_group_infos; i++)
+ kfree(group_info[i]);
+ kvfree(group_info);
+ rcu_read_unlock();
+ }
+ ext4_mb_avg_fragment_size_destroy(sbi);
+ ext4_mb_largest_free_orders_destroy(sbi);
+ kfree(sbi->s_mb_offsets);
+ kfree(sbi->s_mb_maxs);
+ iput(sbi->s_buddy_cache);
+ if (sbi->s_mb_stats) {
+ ext4_msg(sb, KERN_INFO,
+ "mballoc: %u blocks %u reqs (%u success)",
+ atomic_read(&sbi->s_bal_allocated),
+ atomic_read(&sbi->s_bal_reqs),
+ atomic_read(&sbi->s_bal_success));
+ ext4_msg(sb, KERN_INFO,
+ "mballoc: %u extents scanned, %u groups scanned, %u goal hits, "
+ "%u 2^N hits, %u breaks, %u lost",
+ atomic_read(&sbi->s_bal_ex_scanned),
+ atomic_read(&sbi->s_bal_groups_scanned),
+ atomic_read(&sbi->s_bal_goals),
+ atomic_read(&sbi->s_bal_2orders),
+ atomic_read(&sbi->s_bal_breaks),
+ atomic_read(&sbi->s_mb_lost_chunks));
+ ext4_msg(sb, KERN_INFO,
+ "mballoc: %u generated and it took %llu",
+ atomic_read(&sbi->s_mb_buddies_generated),
+ atomic64_read(&sbi->s_mb_generation_time));
+ ext4_msg(sb, KERN_INFO,
+ "mballoc: %u preallocated, %u discarded",
+ atomic_read(&sbi->s_mb_preallocated),
+ atomic_read(&sbi->s_mb_discarded));
+ }
+
+ free_percpu(sbi->s_locality_groups);
+ kfree(sbi->s_mb_last_groups);
+}
+
+static inline int ext4_issue_discard(struct super_block *sb,
+ ext4_group_t block_group, ext4_grpblk_t cluster, int count)
+{
+ ext4_fsblk_t discard_block;
+
+ discard_block = (EXT4_C2B(EXT4_SB(sb), cluster) +
+ ext4_group_first_block_no(sb, block_group));
+ count = EXT4_C2B(EXT4_SB(sb), count);
+ trace_ext4_discard_blocks(sb,
+ (unsigned long long) discard_block, count);
+
+ return sb_issue_discard(sb, discard_block, count, GFP_NOFS, 0);
+}
+
+static void ext4_free_data_in_buddy(struct super_block *sb,
+ struct ext4_free_data *entry)
+{
+ struct ext4_buddy e4b;
+ struct ext4_group_info *db;
+ int err, count = 0;
+
+ mb_debug(sb, "gonna free %u blocks in group %u (0x%p):",
+ entry->efd_count, entry->efd_group, entry);
+
+ err = ext4_mb_load_buddy(sb, entry->efd_group, &e4b);
+ /* we expect to find existing buddy because it's pinned */
+ BUG_ON(err != 0);
+
+ atomic_sub(entry->efd_count, &EXT4_SB(sb)->s_mb_free_pending);
+ db = e4b.bd_info;
+ /* there are blocks to put in buddy to make them really free */
+ count += entry->efd_count;
+ ext4_lock_group(sb, entry->efd_group);
+ /* Take it out of per group rb tree */
+ rb_erase(&entry->efd_node, &(db->bb_free_root));
+ mb_free_blocks(NULL, &e4b, entry->efd_start_cluster, entry->efd_count);
+
+ /*
+ * Clear the trimmed flag for the group so that the next
+ * ext4_trim_fs can trim it.
+ */
+ EXT4_MB_GRP_CLEAR_TRIMMED(db);
+
+ if (!db->bb_free_root.rb_node) {
+ /* No more items in the per group rb tree
+ * balance refcounts from ext4_mb_free_metadata()
+ */
+ folio_put(e4b.bd_buddy_folio);
+ folio_put(e4b.bd_bitmap_folio);
+ }
+ ext4_unlock_group(sb, entry->efd_group);
+ ext4_mb_unload_buddy(&e4b);
+
+ mb_debug(sb, "freed %d blocks in 1 structures\n", count);
+}
+
+/*
+ * This function is called by the jbd2 layer once the commit has finished,
+ * so we know we can free the blocks that were released with that commit.
+ */
+void ext4_process_freed_data(struct super_block *sb, tid_t commit_tid)
+{
+ struct ext4_sb_info *sbi = EXT4_SB(sb);
+ struct ext4_free_data *entry, *tmp;
+ LIST_HEAD(freed_data_list);
+ struct list_head *s_freed_head = &sbi->s_freed_data_list[commit_tid & 1];
+ bool wake;
+
+ list_replace_init(s_freed_head, &freed_data_list);
+
+ list_for_each_entry(entry, &freed_data_list, efd_list)
+ ext4_free_data_in_buddy(sb, entry);
+
+ if (test_opt(sb, DISCARD)) {
+ spin_lock(&sbi->s_md_lock);
+ wake = list_empty(&sbi->s_discard_list);
+ list_splice_tail(&freed_data_list, &sbi->s_discard_list);
+ spin_unlock(&sbi->s_md_lock);
+ if (wake)
+ queue_work(system_dfl_wq, &sbi->s_discard_work);
+ } else {
+ list_for_each_entry_safe(entry, tmp, &freed_data_list, efd_list)
+ kmem_cache_free(ext4_free_data_cachep, entry);
+ }
+}
+
+int __init ext4_init_mballoc(void)
+{
+ ext4_pspace_cachep = KMEM_CACHE(ext4_prealloc_space,
+ SLAB_RECLAIM_ACCOUNT);
+ if (ext4_pspace_cachep == NULL)
+ goto out;
+
+ ext4_ac_cachep = KMEM_CACHE(ext4_allocation_context,
+ SLAB_RECLAIM_ACCOUNT);
+ if (ext4_ac_cachep == NULL)
+ goto out_pa_free;
+
+ ext4_free_data_cachep = KMEM_CACHE(ext4_free_data,
+ SLAB_RECLAIM_ACCOUNT);
+ if (ext4_free_data_cachep == NULL)
+ goto out_ac_free;
+
+ return 0;
+
+out_ac_free:
+ kmem_cache_destroy(ext4_ac_cachep);
+out_pa_free:
+ kmem_cache_destroy(ext4_pspace_cachep);
+out:
+ return -ENOMEM;
+}
+
+void ext4_exit_mballoc(void)
+{
+ /*
+ * Wait for completion of call_rcu()'s on ext4_pspace_cachep
+ * before destroying the slab cache.
+ */
+ rcu_barrier();
+ kmem_cache_destroy(ext4_pspace_cachep);
+ kmem_cache_destroy(ext4_ac_cachep);
+ kmem_cache_destroy(ext4_free_data_cachep);
+ ext4_groupinfo_destroy_slabs();
+}
+
+#define EXT4_MB_BITMAP_MARKED_CHECK 0x0001
+#define EXT4_MB_SYNC_UPDATE 0x0002
+static int
+ext4_mb_mark_context(handle_t *handle, struct super_block *sb, bool state,
+ ext4_group_t group, ext4_grpblk_t blkoff,
+ ext4_grpblk_t len, int flags, ext4_grpblk_t *ret_changed)
+{
+ struct ext4_sb_info *sbi = EXT4_SB(sb);
+ struct buffer_head *bitmap_bh = NULL;
+ struct ext4_group_desc *gdp;
+ struct buffer_head *gdp_bh;
+ int err;
+ unsigned int i, already, changed = len;
+
+ KUNIT_STATIC_STUB_REDIRECT(ext4_mb_mark_context,
+ handle, sb, state, group, blkoff, len,
+ flags, ret_changed);
+
+ if (ret_changed)
+ *ret_changed = 0;
+ bitmap_bh = ext4_read_block_bitmap(sb, group);
+ if (IS_ERR(bitmap_bh))
+ return PTR_ERR(bitmap_bh);
+
+ if (handle) {
+ BUFFER_TRACE(bitmap_bh, "getting write access");
+ err = ext4_journal_get_write_access(handle, sb, bitmap_bh,
+ EXT4_JTR_NONE);
+ if (err)
+ goto out_err;
+ }
+
+ err = -EIO;
+ gdp = ext4_get_group_desc(sb, group, &gdp_bh);
+ if (!gdp)
+ goto out_err;
+
+ if (handle) {
+ BUFFER_TRACE(gdp_bh, "get_write_access");
+ err = ext4_journal_get_write_access(handle, sb, gdp_bh,
+ EXT4_JTR_NONE);
+ if (err)
+ goto out_err;
+ }
+
+ ext4_lock_group(sb, group);
+ if (ext4_has_group_desc_csum(sb) &&
+ (gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT))) {
+ gdp->bg_flags &= cpu_to_le16(~EXT4_BG_BLOCK_UNINIT);
+ ext4_free_group_clusters_set(sb, gdp,
+ ext4_free_clusters_after_init(sb, group, gdp));
+ }
+
+ if (flags & EXT4_MB_BITMAP_MARKED_CHECK) {
+ already = 0;
+ for (i = 0; i < len; i++)
+ if (mb_test_bit(blkoff + i, bitmap_bh->b_data) ==
+ state)
+ already++;
+ changed = len - already;
+ }
+
+ if (state) {
+ mb_set_bits(bitmap_bh->b_data, blkoff, len);
+ ext4_free_group_clusters_set(sb, gdp,
+ ext4_free_group_clusters(sb, gdp) - changed);
+ } else {
+ mb_clear_bits(bitmap_bh->b_data, blkoff, len);
+ ext4_free_group_clusters_set(sb, gdp,
+ ext4_free_group_clusters(sb, gdp) + changed);
+ }
+
+ ext4_block_bitmap_csum_set(sb, gdp, bitmap_bh);
+ ext4_group_desc_csum_set(sb, group, gdp);
+ ext4_unlock_group(sb, group);
+ if (ret_changed)
+ *ret_changed = changed;
+
+ if (sbi->s_log_groups_per_flex) {
+ ext4_group_t flex_group = ext4_flex_group(sbi, group);
+ struct flex_groups *fg = sbi_array_rcu_deref(sbi,
+ s_flex_groups, flex_group);
+
+ if (state)
+ atomic64_sub(changed, &fg->free_clusters);
+ else
+ atomic64_add(changed, &fg->free_clusters);
+ }
+
+ err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
+ if (err)
+ goto out_err;
+ err = ext4_handle_dirty_metadata(handle, NULL, gdp_bh);
+ if (err)
+ goto out_err;
+
+ if (flags & EXT4_MB_SYNC_UPDATE) {
+ sync_dirty_buffer(bitmap_bh);
+ sync_dirty_buffer(gdp_bh);
+ }
+
+out_err:
+ brelse(bitmap_bh);
+ return err;
+}
+
+/*
+ * Check quota and mark chosen space (ac->ac_b_ex) non-free in bitmaps
+ * Returns 0 if success or error code
+ */
+static noinline_for_stack int
+ext4_mb_mark_diskspace_used(struct ext4_allocation_context *ac,
+ handle_t *handle, unsigned int reserv_clstrs)
+{
+ struct ext4_group_desc *gdp;
+ struct ext4_sb_info *sbi;
+ struct super_block *sb;
+ ext4_fsblk_t block;
+ int err, len;
+ int flags = 0;
+ ext4_grpblk_t changed;
+
+ BUG_ON(ac->ac_status != AC_STATUS_FOUND);
+ BUG_ON(ac->ac_b_ex.fe_len <= 0);
+
+ sb = ac->ac_sb;
+ sbi = EXT4_SB(sb);
+
+ gdp = ext4_get_group_desc(sb, ac->ac_b_ex.fe_group, NULL);
+ if (!gdp)
+ return -EIO;
+ ext4_debug("using block group %u(%d)\n", ac->ac_b_ex.fe_group,
+ ext4_free_group_clusters(sb, gdp));
+
+ block = ext4_grp_offs_to_block(sb, &ac->ac_b_ex);
+ len = EXT4_C2B(sbi, ac->ac_b_ex.fe_len);
+ if (!ext4_inode_block_valid(ac->ac_inode, block, len)) {
+ ext4_error(sb, "Allocating blocks %llu-%llu which overlap "
+ "fs metadata", block, block+len);
+ /* File system mounted not to panic on error
+ * Fix the bitmap and return EFSCORRUPTED
+ * We leak some of the blocks here.
+ */
+ err = ext4_mb_mark_context(handle, sb, true,
+ ac->ac_b_ex.fe_group,
+ ac->ac_b_ex.fe_start,
+ ac->ac_b_ex.fe_len,
+ 0, NULL);
+ if (!err)
+ err = -EFSCORRUPTED;
+ return err;
+ }
+
+#ifdef AGGRESSIVE_CHECK
+ flags |= EXT4_MB_BITMAP_MARKED_CHECK;
+#endif
+ err = ext4_mb_mark_context(handle, sb, true, ac->ac_b_ex.fe_group,
+ ac->ac_b_ex.fe_start, ac->ac_b_ex.fe_len,
+ flags, &changed);
+
+ if (err && changed == 0)
+ return err;
+
+#ifdef AGGRESSIVE_CHECK
+ BUG_ON(changed != ac->ac_b_ex.fe_len);
+#endif
+ percpu_counter_sub(&sbi->s_freeclusters_counter, ac->ac_b_ex.fe_len);
+ /*
+ * Now reduce the dirty block count also. Should not go negative
+ */
+ if (!(ac->ac_flags & EXT4_MB_DELALLOC_RESERVED))
+ /* release all the reserved blocks if non delalloc */
+ percpu_counter_sub(&sbi->s_dirtyclusters_counter,
+ reserv_clstrs);
+
+ return err;
+}
+
+/*
+ * Idempotent helper for Ext4 fast commit replay path to set the state of
+ * blocks in bitmaps and update counters.
+ */
+void ext4_mb_mark_bb(struct super_block *sb, ext4_fsblk_t block,
+ int len, bool state)
+{
+ struct ext4_sb_info *sbi = EXT4_SB(sb);
+ ext4_group_t group;
+ ext4_grpblk_t blkoff;
+ int err = 0;
+ unsigned int clen, thisgrp_len;
+
+ while (len > 0) {
+ ext4_get_group_no_and_offset(sb, block, &group, &blkoff);
+
+ /*
+ * Check to see if we are freeing blocks across a group
+ * boundary.
+ * In case of flex_bg, this can happen that (block, len) may
+ * span across more than one group. In that case we need to
+ * get the corresponding group metadata to work with.
+ * For this we have goto again loop.
+ */
+ thisgrp_len = min_t(unsigned int, (unsigned int)len,
+ EXT4_BLOCKS_PER_GROUP(sb) - EXT4_C2B(sbi, blkoff));
+ clen = EXT4_NUM_B2C(sbi, thisgrp_len);
+
+ if (!ext4_sb_block_valid(sb, NULL, block, thisgrp_len)) {
+ ext4_error(sb, "Marking blocks in system zone - "
+ "Block = %llu, len = %u",
+ block, thisgrp_len);
+ break;
+ }
+
+ err = ext4_mb_mark_context(NULL, sb, state,
+ group, blkoff, clen,
+ EXT4_MB_BITMAP_MARKED_CHECK |
+ EXT4_MB_SYNC_UPDATE,
+ NULL);
+ if (err)
+ break;
+
+ block += thisgrp_len;
+ len -= thisgrp_len;
+ BUG_ON(len < 0);
+ }
+}
+
+/*
+ * here we normalize request for locality group
+ * Group request are normalized to s_mb_group_prealloc, which goes to
+ * s_strip if we set the same via mount option.
+ * s_mb_group_prealloc can be configured via
+ * /sys/fs/ext4/<partition>/mb_group_prealloc
+ *
+ * XXX: should we try to preallocate more than the group has now?
+ */
+static void ext4_mb_normalize_group_request(struct ext4_allocation_context *ac)
+{
+ struct super_block *sb = ac->ac_sb;
+ struct ext4_locality_group *lg = ac->ac_lg;
+
+ BUG_ON(lg == NULL);
+ ac->ac_g_ex.fe_len = EXT4_SB(sb)->s_mb_group_prealloc;
+ mb_debug(sb, "goal %u blocks for locality group\n", ac->ac_g_ex.fe_len);
+}
+
+/*
+ * This function returns the next element to look at during inode
+ * PA rbtree walk. We assume that we have held the inode PA rbtree lock
+ * (ei->i_prealloc_lock)
+ *
+ * new_start The start of the range we want to compare
+ * cur_start The existing start that we are comparing against
+ * node The node of the rb_tree
+ */
+static inline struct rb_node*
+ext4_mb_pa_rb_next_iter(ext4_lblk_t new_start, ext4_lblk_t cur_start, struct rb_node *node)
+{
+ if (new_start < cur_start)
+ return node->rb_left;
+ else
+ return node->rb_right;
+}
+
+static inline void
+ext4_mb_pa_assert_overlap(struct ext4_allocation_context *ac,
+ ext4_lblk_t start, loff_t end)
+{
+ struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
+ struct ext4_inode_info *ei = EXT4_I(ac->ac_inode);
+ struct ext4_prealloc_space *tmp_pa;
+ ext4_lblk_t tmp_pa_start;
+ loff_t tmp_pa_end;
+ struct rb_node *iter;
+
+ read_lock(&ei->i_prealloc_lock);
+ for (iter = ei->i_prealloc_node.rb_node; iter;
+ iter = ext4_mb_pa_rb_next_iter(start, tmp_pa_start, iter)) {
+ tmp_pa = rb_entry(iter, struct ext4_prealloc_space,
+ pa_node.inode_node);
+ tmp_pa_start = tmp_pa->pa_lstart;
+ tmp_pa_end = pa_logical_end(sbi, tmp_pa);
+
+ spin_lock(&tmp_pa->pa_lock);
+ if (tmp_pa->pa_deleted == 0)
+ BUG_ON(!(start >= tmp_pa_end || end <= tmp_pa_start));
+ spin_unlock(&tmp_pa->pa_lock);
+ }
+ read_unlock(&ei->i_prealloc_lock);
+}
+
+/*
+ * Given an allocation context "ac" and a range "start", "end", check
+ * and adjust boundaries if the range overlaps with any of the existing
+ * preallocatoins stored in the corresponding inode of the allocation context.
+ *
+ * Parameters:
+ * ac allocation context
+ * start start of the new range
+ * end end of the new range
+ */
+static inline void
+ext4_mb_pa_adjust_overlap(struct ext4_allocation_context *ac,
+ ext4_lblk_t *start, loff_t *end)
+{
+ struct ext4_inode_info *ei = EXT4_I(ac->ac_inode);
+ struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
+ struct ext4_prealloc_space *tmp_pa = NULL, *left_pa = NULL, *right_pa = NULL;
+ struct rb_node *iter;
+ ext4_lblk_t new_start, tmp_pa_start, right_pa_start = -1;
+ loff_t new_end, tmp_pa_end, left_pa_end = -1;
+
+ new_start = *start;
+ new_end = *end;
+
+ /*
+ * Adjust the normalized range so that it doesn't overlap with any
+ * existing preallocated blocks(PAs). Make sure to hold the rbtree lock
+ * so it doesn't change underneath us.
+ */
+ read_lock(&ei->i_prealloc_lock);
+
+ /* Step 1: find any one immediate neighboring PA of the normalized range */
+ for (iter = ei->i_prealloc_node.rb_node; iter;
+ iter = ext4_mb_pa_rb_next_iter(ac->ac_o_ex.fe_logical,
+ tmp_pa_start, iter)) {
+ tmp_pa = rb_entry(iter, struct ext4_prealloc_space,
+ pa_node.inode_node);
+ tmp_pa_start = tmp_pa->pa_lstart;
+ tmp_pa_end = pa_logical_end(sbi, tmp_pa);
+
+ /* PA must not overlap original request */
+ spin_lock(&tmp_pa->pa_lock);
+ if (tmp_pa->pa_deleted == 0)
+ BUG_ON(!(ac->ac_o_ex.fe_logical >= tmp_pa_end ||
+ ac->ac_o_ex.fe_logical < tmp_pa_start));
+ spin_unlock(&tmp_pa->pa_lock);
+ }
+
+ /*
+ * Step 2: check if the found PA is left or right neighbor and
+ * get the other neighbor
+ */
+ if (tmp_pa) {
+ if (tmp_pa->pa_lstart < ac->ac_o_ex.fe_logical) {
+ struct rb_node *tmp;
+
+ left_pa = tmp_pa;
+ tmp = rb_next(&left_pa->pa_node.inode_node);
+ if (tmp) {
+ right_pa = rb_entry(tmp,
+ struct ext4_prealloc_space,
+ pa_node.inode_node);
+ }
+ } else {
+ struct rb_node *tmp;
+
+ right_pa = tmp_pa;
+ tmp = rb_prev(&right_pa->pa_node.inode_node);
+ if (tmp) {
+ left_pa = rb_entry(tmp,
+ struct ext4_prealloc_space,
+ pa_node.inode_node);
+ }
+ }
+ }
+
+ /* Step 3: get the non deleted neighbors */
+ if (left_pa) {
+ for (iter = &left_pa->pa_node.inode_node;;
+ iter = rb_prev(iter)) {
+ if (!iter) {
+ left_pa = NULL;
+ break;
+ }
+
+ tmp_pa = rb_entry(iter, struct ext4_prealloc_space,
+ pa_node.inode_node);
+ left_pa = tmp_pa;
+ spin_lock(&tmp_pa->pa_lock);
+ if (tmp_pa->pa_deleted == 0) {
+ spin_unlock(&tmp_pa->pa_lock);
+ break;
+ }
+ spin_unlock(&tmp_pa->pa_lock);
+ }
+ }
+
+ if (right_pa) {
+ for (iter = &right_pa->pa_node.inode_node;;
+ iter = rb_next(iter)) {
+ if (!iter) {
+ right_pa = NULL;
+ break;
+ }
+
+ tmp_pa = rb_entry(iter, struct ext4_prealloc_space,
+ pa_node.inode_node);
+ right_pa = tmp_pa;
+ spin_lock(&tmp_pa->pa_lock);
+ if (tmp_pa->pa_deleted == 0) {
+ spin_unlock(&tmp_pa->pa_lock);
+ break;
+ }
+ spin_unlock(&tmp_pa->pa_lock);
+ }
+ }
+
+ if (left_pa) {
+ left_pa_end = pa_logical_end(sbi, left_pa);
+ BUG_ON(left_pa_end > ac->ac_o_ex.fe_logical);
+ }
+
+ if (right_pa) {
+ right_pa_start = right_pa->pa_lstart;
+ BUG_ON(right_pa_start <= ac->ac_o_ex.fe_logical);
+ }
+
+ /* Step 4: trim our normalized range to not overlap with the neighbors */
+ if (left_pa) {
+ if (left_pa_end > new_start)
+ new_start = left_pa_end;
+ }
+
+ if (right_pa) {
+ if (right_pa_start < new_end)
+ new_end = right_pa_start;
+ }
+ read_unlock(&ei->i_prealloc_lock);
+
+ /* XXX: extra loop to check we really don't overlap preallocations */
+ ext4_mb_pa_assert_overlap(ac, new_start, new_end);
+
+ *start = new_start;
+ *end = new_end;
+}
+
+/*
+ * Normalization means making request better in terms of
+ * size and alignment
+ */
+static noinline_for_stack void
+ext4_mb_normalize_request(struct ext4_allocation_context *ac,
+ struct ext4_allocation_request *ar)
+{
+ struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
+ struct ext4_super_block *es = sbi->s_es;
+ int bsbits, max;
+ loff_t size, start_off, end;
+ loff_t orig_size __maybe_unused;
+ ext4_lblk_t start;
+
+ /* do normalize only data requests, metadata requests
+ do not need preallocation */
+ if (!(ac->ac_flags & EXT4_MB_HINT_DATA))
+ return;
+
+ /* sometime caller may want exact blocks */
+ if (unlikely(ac->ac_flags & EXT4_MB_HINT_GOAL_ONLY))
+ return;
+
+ /* caller may indicate that preallocation isn't
+ * required (it's a tail, for example) */
+ if (ac->ac_flags & EXT4_MB_HINT_NOPREALLOC)
+ return;
+
+ if (ac->ac_flags & EXT4_MB_HINT_GROUP_ALLOC) {
+ ext4_mb_normalize_group_request(ac);
+ return ;
+ }
+
+ bsbits = ac->ac_sb->s_blocksize_bits;
+
+ /* first, let's learn actual file size
+ * given current request is allocated */
+ size = extent_logical_end(sbi, &ac->ac_o_ex);
+ size = size << bsbits;
+ if (size < i_size_read(ac->ac_inode))
+ size = i_size_read(ac->ac_inode);
+ orig_size = size;
+
+ /* max size of free chunks */
+ max = 2 << bsbits;
+
+#define NRL_CHECK_SIZE(req, size, max, chunk_size) \
+ (req <= (size) || max <= (chunk_size))
+
+ /* first, try to predict filesize */
+ /* XXX: should this table be tunable? */
+ start_off = 0;
+ if (size <= 16 * 1024) {
+ size = 16 * 1024;
+ } else if (size <= 32 * 1024) {
+ size = 32 * 1024;
+ } else if (size <= 64 * 1024) {
+ size = 64 * 1024;
+ } else if (size <= 128 * 1024) {
+ size = 128 * 1024;
+ } else if (size <= 256 * 1024) {
+ size = 256 * 1024;
+ } else if (size <= 512 * 1024) {
+ size = 512 * 1024;
+ } else if (size <= 1024 * 1024) {
+ size = 1024 * 1024;
+ } else if (NRL_CHECK_SIZE(size, 4 * 1024 * 1024, max, 2 * 1024)) {
+ start_off = ((loff_t)ac->ac_o_ex.fe_logical >>
+ (21 - bsbits)) << 21;
+ size = 2 * 1024 * 1024;
+ } else if (NRL_CHECK_SIZE(size, 8 * 1024 * 1024, max, 4 * 1024)) {
+ start_off = ((loff_t)ac->ac_o_ex.fe_logical >>
+ (22 - bsbits)) << 22;
+ size = 4 * 1024 * 1024;
+ } else if (NRL_CHECK_SIZE(EXT4_C2B(sbi, ac->ac_o_ex.fe_len),
+ (8<<20)>>bsbits, max, 8 * 1024)) {
+ start_off = ((loff_t)ac->ac_o_ex.fe_logical >>
+ (23 - bsbits)) << 23;
+ size = 8 * 1024 * 1024;
+ } else {
+ start_off = (loff_t) ac->ac_o_ex.fe_logical << bsbits;
+ size = (loff_t) EXT4_C2B(sbi,
+ ac->ac_o_ex.fe_len) << bsbits;
+ }
+ size = size >> bsbits;
+ start = start_off >> bsbits;
+
+ /*
+ * For tiny groups (smaller than 8MB) the chosen allocation
+ * alignment may be larger than group size. Make sure the
+ * alignment does not move allocation to a different group which
+ * makes mballoc fail assertions later.
+ */
+ start = max(start, rounddown(ac->ac_o_ex.fe_logical,
+ (ext4_lblk_t)EXT4_BLOCKS_PER_GROUP(ac->ac_sb)));
+
+ /* avoid unnecessary preallocation that may trigger assertions */
+ if (start + size > EXT_MAX_BLOCKS)
+ size = EXT_MAX_BLOCKS - start;
+
+ /* don't cover already allocated blocks in selected range */
+ if (ar->pleft && start <= ar->lleft) {
+ size -= ar->lleft + 1 - start;
+ start = ar->lleft + 1;
+ }
+ if (ar->pright && start + size - 1 >= ar->lright)
+ size -= start + size - ar->lright;
+
+ /*
+ * Trim allocation request for filesystems with artificially small
+ * groups.
+ */
+ if (size > EXT4_BLOCKS_PER_GROUP(ac->ac_sb))
+ size = EXT4_BLOCKS_PER_GROUP(ac->ac_sb);
+
+ end = start + size;
+
+ ext4_mb_pa_adjust_overlap(ac, &start, &end);
+
+ size = end - start;
+
+ /*
+ * In this function "start" and "size" are normalized for better
+ * alignment and length such that we could preallocate more blocks.
+ * This normalization is done such that original request of
+ * ac->ac_o_ex.fe_logical & fe_len should always lie within "start" and
+ * "size" boundaries.
+ * (Note fe_len can be relaxed since FS block allocation API does not
+ * provide gurantee on number of contiguous blocks allocation since that
+ * depends upon free space left, etc).
+ * In case of inode pa, later we use the allocated blocks
+ * [pa_pstart + fe_logical - pa_lstart, fe_len/size] from the preallocated
+ * range of goal/best blocks [start, size] to put it at the
+ * ac_o_ex.fe_logical extent of this inode.
+ * (See ext4_mb_use_inode_pa() for more details)
+ */
+ if (start + size <= ac->ac_o_ex.fe_logical ||
+ start > ac->ac_o_ex.fe_logical) {
+ ext4_msg(ac->ac_sb, KERN_ERR,
+ "start %lu, size %lu, fe_logical %lu",
+ (unsigned long) start, (unsigned long) size,
+ (unsigned long) ac->ac_o_ex.fe_logical);
+ BUG();
+ }
+ BUG_ON(size <= 0 || size > EXT4_BLOCKS_PER_GROUP(ac->ac_sb));
+
+ /* now prepare goal request */
+
+ /* XXX: is it better to align blocks WRT to logical
+ * placement or satisfy big request as is */
+ ac->ac_g_ex.fe_logical = start;
+ ac->ac_g_ex.fe_len = EXT4_NUM_B2C(sbi, size);
+ ac->ac_orig_goal_len = ac->ac_g_ex.fe_len;
+
+ /* define goal start in order to merge */
+ if (ar->pright && (ar->lright == (start + size)) &&
+ ar->pright >= size &&
+ ar->pright - size >= le32_to_cpu(es->s_first_data_block)) {
+ /* merge to the right */
+ ext4_get_group_no_and_offset(ac->ac_sb, ar->pright - size,
+ &ac->ac_g_ex.fe_group,
+ &ac->ac_g_ex.fe_start);
+ ac->ac_flags |= EXT4_MB_HINT_TRY_GOAL;
+ }
+ if (ar->pleft && (ar->lleft + 1 == start) &&
+ ar->pleft + 1 < ext4_blocks_count(es)) {
+ /* merge to the left */
+ ext4_get_group_no_and_offset(ac->ac_sb, ar->pleft + 1,
+ &ac->ac_g_ex.fe_group,
+ &ac->ac_g_ex.fe_start);
+ ac->ac_flags |= EXT4_MB_HINT_TRY_GOAL;
+ }
+
+ mb_debug(ac->ac_sb, "goal: %lld(was %lld) blocks at %u\n", size,
+ orig_size, start);
+}
+
+static void ext4_mb_collect_stats(struct ext4_allocation_context *ac)
+{
+ struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
+
+ if (sbi->s_mb_stats && ac->ac_g_ex.fe_len >= 1) {
+ atomic_inc(&sbi->s_bal_reqs);
+ atomic_add(ac->ac_b_ex.fe_len, &sbi->s_bal_allocated);
+ if (ac->ac_b_ex.fe_len >= ac->ac_o_ex.fe_len)
+ atomic_inc(&sbi->s_bal_success);
+
+ atomic_add(ac->ac_found, &sbi->s_bal_ex_scanned);
+ for (int i=0; i<EXT4_MB_NUM_CRS; i++) {
+ atomic_add(ac->ac_cX_found[i], &sbi->s_bal_cX_ex_scanned[i]);
+ }
+
+ atomic_add(ac->ac_groups_scanned, &sbi->s_bal_groups_scanned);
+ if (ac->ac_g_ex.fe_start == ac->ac_b_ex.fe_start &&
+ ac->ac_g_ex.fe_group == ac->ac_b_ex.fe_group)
+ atomic_inc(&sbi->s_bal_goals);
+ /* did we allocate as much as normalizer originally wanted? */
+ if (ac->ac_f_ex.fe_len == ac->ac_orig_goal_len)
+ atomic_inc(&sbi->s_bal_len_goals);
+
+ if (ac->ac_found > sbi->s_mb_max_to_scan)
+ atomic_inc(&sbi->s_bal_breaks);
+ }
+
+ if (ac->ac_op == EXT4_MB_HISTORY_ALLOC)
+ trace_ext4_mballoc_alloc(ac);
+ else
+ trace_ext4_mballoc_prealloc(ac);
+}
+
+/*
+ * Called on failure; free up any blocks from the inode PA for this
+ * context. We don't need this for MB_GROUP_PA because we only change
+ * pa_free in ext4_mb_release_context(), but on failure, we've already
+ * zeroed out ac->ac_b_ex.fe_len, so group_pa->pa_free is not changed.
+ */
+static void ext4_discard_allocated_blocks(struct ext4_allocation_context *ac)
+{
+ struct ext4_prealloc_space *pa = ac->ac_pa;
+ struct ext4_buddy e4b;
+ int err;
+
+ if (pa == NULL) {
+ if (ac->ac_f_ex.fe_len == 0)
+ return;
+ err = ext4_mb_load_buddy(ac->ac_sb, ac->ac_f_ex.fe_group, &e4b);
+ if (WARN_RATELIMIT(err,
+ "ext4: mb_load_buddy failed (%d)", err))
+ /*
+ * This should never happen since we pin the
+ * pages in the ext4_allocation_context so
+ * ext4_mb_load_buddy() should never fail.
+ */
+ return;
+ ext4_lock_group(ac->ac_sb, ac->ac_f_ex.fe_group);
+ mb_free_blocks(ac->ac_inode, &e4b, ac->ac_f_ex.fe_start,
+ ac->ac_f_ex.fe_len);
+ ext4_unlock_group(ac->ac_sb, ac->ac_f_ex.fe_group);
+ ext4_mb_unload_buddy(&e4b);
+ return;
+ }
+ if (pa->pa_type == MB_INODE_PA) {
+ spin_lock(&pa->pa_lock);
+ pa->pa_free += ac->ac_b_ex.fe_len;
+ spin_unlock(&pa->pa_lock);
+ }
+}
+
+/*
+ * use blocks preallocated to inode
+ */
+static void ext4_mb_use_inode_pa(struct ext4_allocation_context *ac,
+ struct ext4_prealloc_space *pa)
+{
+ struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
+ ext4_fsblk_t start;
+ ext4_fsblk_t end;
+ int len;
+
+ /* found preallocated blocks, use them */
+ start = pa->pa_pstart + (ac->ac_o_ex.fe_logical - pa->pa_lstart);
+ end = min(pa->pa_pstart + EXT4_C2B(sbi, pa->pa_len),
+ start + EXT4_C2B(sbi, ac->ac_o_ex.fe_len));
+ len = EXT4_NUM_B2C(sbi, end - start);
+ ext4_get_group_no_and_offset(ac->ac_sb, start, &ac->ac_b_ex.fe_group,
+ &ac->ac_b_ex.fe_start);
+ ac->ac_b_ex.fe_len = len;
+ ac->ac_status = AC_STATUS_FOUND;
+ ac->ac_pa = pa;
+
+ BUG_ON(start < pa->pa_pstart);
+ BUG_ON(end > pa->pa_pstart + EXT4_C2B(sbi, pa->pa_len));
+ BUG_ON(pa->pa_free < len);
+ BUG_ON(ac->ac_b_ex.fe_len <= 0);
+ pa->pa_free -= len;
+
+ mb_debug(ac->ac_sb, "use %llu/%d from inode pa %p\n", start, len, pa);
+}
+
+/*
+ * use blocks preallocated to locality group
+ */
+static void ext4_mb_use_group_pa(struct ext4_allocation_context *ac,
+ struct ext4_prealloc_space *pa)
+{
+ unsigned int len = ac->ac_o_ex.fe_len;
+
+ ext4_get_group_no_and_offset(ac->ac_sb, pa->pa_pstart,
+ &ac->ac_b_ex.fe_group,
+ &ac->ac_b_ex.fe_start);
+ ac->ac_b_ex.fe_len = len;
+ ac->ac_status = AC_STATUS_FOUND;
+ ac->ac_pa = pa;
+
+ /* we don't correct pa_pstart or pa_len here to avoid
+ * possible race when the group is being loaded concurrently
+ * instead we correct pa later, after blocks are marked
+ * in on-disk bitmap -- see ext4_mb_release_context()
+ * Other CPUs are prevented from allocating from this pa by lg_mutex
+ */
+ mb_debug(ac->ac_sb, "use %u/%u from group pa %p\n",
+ pa->pa_lstart, len, pa);
+}
+
+/*
+ * Return the prealloc space that have minimal distance
+ * from the goal block. @cpa is the prealloc
+ * space that is having currently known minimal distance
+ * from the goal block.
+ */
+static struct ext4_prealloc_space *
+ext4_mb_check_group_pa(ext4_fsblk_t goal_block,
+ struct ext4_prealloc_space *pa,
+ struct ext4_prealloc_space *cpa)
+{
+ ext4_fsblk_t cur_distance, new_distance;
+
+ if (cpa == NULL) {
+ atomic_inc(&pa->pa_count);
+ return pa;
+ }
+ cur_distance = abs(goal_block - cpa->pa_pstart);
+ new_distance = abs(goal_block - pa->pa_pstart);
+
+ if (cur_distance <= new_distance)
+ return cpa;
+
+ /* drop the previous reference */
+ atomic_dec(&cpa->pa_count);
+ atomic_inc(&pa->pa_count);
+ return pa;
+}
+
+/*
+ * check if found pa meets EXT4_MB_HINT_GOAL_ONLY
+ */
+static bool
+ext4_mb_pa_goal_check(struct ext4_allocation_context *ac,
+ struct ext4_prealloc_space *pa)
+{
+ struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
+ ext4_fsblk_t start;
+
+ if (likely(!(ac->ac_flags & EXT4_MB_HINT_GOAL_ONLY)))
+ return true;
+
+ /*
+ * If EXT4_MB_HINT_GOAL_ONLY is set, ac_g_ex will not be adjusted
+ * in ext4_mb_normalize_request and will keep same with ac_o_ex
+ * from ext4_mb_initialize_context. Choose ac_g_ex here to keep
+ * consistent with ext4_mb_find_by_goal.
+ */
+ start = pa->pa_pstart +
+ (ac->ac_g_ex.fe_logical - pa->pa_lstart);
+ if (ext4_grp_offs_to_block(ac->ac_sb, &ac->ac_g_ex) != start)
+ return false;
+
+ if (ac->ac_g_ex.fe_len > pa->pa_len -
+ EXT4_B2C(sbi, ac->ac_g_ex.fe_logical - pa->pa_lstart))
+ return false;
+
+ return true;
+}
+
+/*
+ * search goal blocks in preallocated space
+ */
+static noinline_for_stack bool
+ext4_mb_use_preallocated(struct ext4_allocation_context *ac)
+{
+ struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
+ int order, i;
+ struct ext4_inode_info *ei = EXT4_I(ac->ac_inode);
+ struct ext4_locality_group *lg;
+ struct ext4_prealloc_space *tmp_pa = NULL, *cpa = NULL;
+ struct rb_node *iter;
+ ext4_fsblk_t goal_block;
+
+ /* only data can be preallocated */
+ if (!(ac->ac_flags & EXT4_MB_HINT_DATA))
+ return false;
+
+ /*
+ * first, try per-file preallocation by searching the inode pa rbtree.
+ *
+ * Here, we can't do a direct traversal of the tree because
+ * ext4_mb_discard_group_preallocation() can paralelly mark the pa
+ * deleted and that can cause direct traversal to skip some entries.
+ */
+ read_lock(&ei->i_prealloc_lock);
+
+ if (RB_EMPTY_ROOT(&ei->i_prealloc_node)) {
+ goto try_group_pa;
+ }
+
+ /*
+ * Step 1: Find a pa with logical start immediately adjacent to the
+ * original logical start. This could be on the left or right.
+ *
+ * (tmp_pa->pa_lstart never changes so we can skip locking for it).
+ */
+ for (iter = ei->i_prealloc_node.rb_node; iter;
+ iter = ext4_mb_pa_rb_next_iter(ac->ac_o_ex.fe_logical,
+ tmp_pa->pa_lstart, iter)) {
+ tmp_pa = rb_entry(iter, struct ext4_prealloc_space,
+ pa_node.inode_node);
+ }
+
+ /*
+ * Step 2: The adjacent pa might be to the right of logical start, find
+ * the left adjacent pa. After this step we'd have a valid tmp_pa whose
+ * logical start is towards the left of original request's logical start
+ */
+ if (tmp_pa->pa_lstart > ac->ac_o_ex.fe_logical) {
+ struct rb_node *tmp;
+ tmp = rb_prev(&tmp_pa->pa_node.inode_node);
+
+ if (tmp) {
+ tmp_pa = rb_entry(tmp, struct ext4_prealloc_space,
+ pa_node.inode_node);
+ } else {
+ /*
+ * If there is no adjacent pa to the left then finding
+ * an overlapping pa is not possible hence stop searching
+ * inode pa tree
+ */
+ goto try_group_pa;
+ }
+ }
+
+ BUG_ON(!(tmp_pa && tmp_pa->pa_lstart <= ac->ac_o_ex.fe_logical));
+
+ /*
+ * Step 3: If the left adjacent pa is deleted, keep moving left to find
+ * the first non deleted adjacent pa. After this step we should have a
+ * valid tmp_pa which is guaranteed to be non deleted.
+ */
+ for (iter = &tmp_pa->pa_node.inode_node;; iter = rb_prev(iter)) {
+ if (!iter) {
+ /*
+ * no non deleted left adjacent pa, so stop searching
+ * inode pa tree
+ */
+ goto try_group_pa;
+ }
+ tmp_pa = rb_entry(iter, struct ext4_prealloc_space,
+ pa_node.inode_node);
+ spin_lock(&tmp_pa->pa_lock);
+ if (tmp_pa->pa_deleted == 0) {
+ /*
+ * We will keep holding the pa_lock from
+ * this point on because we don't want group discard
+ * to delete this pa underneath us. Since group
+ * discard is anyways an ENOSPC operation it
+ * should be okay for it to wait a few more cycles.
+ */
+ break;
+ } else {
+ spin_unlock(&tmp_pa->pa_lock);
+ }
+ }
+
+ BUG_ON(!(tmp_pa && tmp_pa->pa_lstart <= ac->ac_o_ex.fe_logical));
+ BUG_ON(tmp_pa->pa_deleted == 1);
+
+ /*
+ * Step 4: We now have the non deleted left adjacent pa. Only this
+ * pa can possibly satisfy the request hence check if it overlaps
+ * original logical start and stop searching if it doesn't.
+ */
+ if (ac->ac_o_ex.fe_logical >= pa_logical_end(sbi, tmp_pa)) {
+ spin_unlock(&tmp_pa->pa_lock);
+ goto try_group_pa;
+ }
+
+ /* non-extent files can't have physical blocks past 2^32 */
+ if (!(ext4_test_inode_flag(ac->ac_inode, EXT4_INODE_EXTENTS)) &&
+ (tmp_pa->pa_pstart + EXT4_C2B(sbi, tmp_pa->pa_len) >
+ EXT4_MAX_BLOCK_FILE_PHYS)) {
+ /*
+ * Since PAs don't overlap, we won't find any other PA to
+ * satisfy this.
+ */
+ spin_unlock(&tmp_pa->pa_lock);
+ goto try_group_pa;
+ }
+
+ if (tmp_pa->pa_free && likely(ext4_mb_pa_goal_check(ac, tmp_pa))) {
+ atomic_inc(&tmp_pa->pa_count);
+ ext4_mb_use_inode_pa(ac, tmp_pa);
+ spin_unlock(&tmp_pa->pa_lock);
+ read_unlock(&ei->i_prealloc_lock);
+ return true;
+ } else {
+ /*
+ * We found a valid overlapping pa but couldn't use it because
+ * it had no free blocks. This should ideally never happen
+ * because:
+ *
+ * 1. When a new inode pa is added to rbtree it must have
+ * pa_free > 0 since otherwise we won't actually need
+ * preallocation.
+ *
+ * 2. An inode pa that is in the rbtree can only have it's
+ * pa_free become zero when another thread calls:
+ * ext4_mb_new_blocks
+ * ext4_mb_use_preallocated
+ * ext4_mb_use_inode_pa
+ *
+ * 3. Further, after the above calls make pa_free == 0, we will
+ * immediately remove it from the rbtree in:
+ * ext4_mb_new_blocks
+ * ext4_mb_release_context
+ * ext4_mb_put_pa
+ *
+ * 4. Since the pa_free becoming 0 and pa_free getting removed
+ * from tree both happen in ext4_mb_new_blocks, which is always
+ * called with i_data_sem held for data allocations, we can be
+ * sure that another process will never see a pa in rbtree with
+ * pa_free == 0.
+ */
+ WARN_ON_ONCE(tmp_pa->pa_free == 0);
+ }
+ spin_unlock(&tmp_pa->pa_lock);
+try_group_pa:
+ read_unlock(&ei->i_prealloc_lock);
+
+ /* can we use group allocation? */
+ if (!(ac->ac_flags & EXT4_MB_HINT_GROUP_ALLOC))
+ return false;
+
+ /* inode may have no locality group for some reason */
+ lg = ac->ac_lg;
+ if (lg == NULL)
+ return false;
+ order = fls(ac->ac_o_ex.fe_len) - 1;
+ if (order > PREALLOC_TB_SIZE - 1)
+ /* The max size of hash table is PREALLOC_TB_SIZE */
+ order = PREALLOC_TB_SIZE - 1;
+
+ goal_block = ext4_grp_offs_to_block(ac->ac_sb, &ac->ac_g_ex);
+ /*
+ * search for the prealloc space that is having
+ * minimal distance from the goal block.
+ */
+ for (i = order; i < PREALLOC_TB_SIZE; i++) {
+ rcu_read_lock();
+ list_for_each_entry_rcu(tmp_pa, &lg->lg_prealloc_list[i],
+ pa_node.lg_list) {
+ spin_lock(&tmp_pa->pa_lock);
+ if (tmp_pa->pa_deleted == 0 &&
+ tmp_pa->pa_free >= ac->ac_o_ex.fe_len) {
+
+ cpa = ext4_mb_check_group_pa(goal_block,
+ tmp_pa, cpa);
+ }
+ spin_unlock(&tmp_pa->pa_lock);
+ }
+ rcu_read_unlock();
+ }
+ if (cpa) {
+ ext4_mb_use_group_pa(ac, cpa);
+ return true;
+ }
+ return false;
+}
+
+/*
+ * the function goes through all preallocation in this group and marks them
+ * used in in-core bitmap. buddy must be generated from this bitmap
+ * Need to be called with ext4 group lock held
+ */
+static noinline_for_stack
+void ext4_mb_generate_from_pa(struct super_block *sb, void *bitmap,
+ ext4_group_t group)
+{
+ struct ext4_group_info *grp = ext4_get_group_info(sb, group);
+ struct ext4_prealloc_space *pa;
+ struct list_head *cur;
+ ext4_group_t groupnr;
+ ext4_grpblk_t start;
+ int preallocated = 0;
+ int len;
+
+ if (!grp)
+ return;
+
+ /* all form of preallocation discards first load group,
+ * so the only competing code is preallocation use.
+ * we don't need any locking here
+ * notice we do NOT ignore preallocations with pa_deleted
+ * otherwise we could leave used blocks available for
+ * allocation in buddy when concurrent ext4_mb_put_pa()
+ * is dropping preallocation
+ */
+ list_for_each(cur, &grp->bb_prealloc_list) {
+ pa = list_entry(cur, struct ext4_prealloc_space, pa_group_list);
+ spin_lock(&pa->pa_lock);
+ ext4_get_group_no_and_offset(sb, pa->pa_pstart,
+ &groupnr, &start);
+ len = pa->pa_len;
+ spin_unlock(&pa->pa_lock);
+ if (unlikely(len == 0))
+ continue;
+ BUG_ON(groupnr != group);
+ mb_set_bits(bitmap, start, len);
+ preallocated += len;
+ }
+ mb_debug(sb, "preallocated %d for group %u\n", preallocated, group);
+}
+
+static void ext4_mb_mark_pa_deleted(struct super_block *sb,
+ struct ext4_prealloc_space *pa)
+{
+ struct ext4_inode_info *ei;
+
+ if (pa->pa_deleted) {
+ ext4_warning(sb, "deleted pa, type:%d, pblk:%llu, lblk:%u, len:%d\n",
+ pa->pa_type, pa->pa_pstart, pa->pa_lstart,
+ pa->pa_len);
+ return;
+ }
+
+ pa->pa_deleted = 1;
+
+ if (pa->pa_type == MB_INODE_PA) {
+ ei = EXT4_I(pa->pa_inode);
+ atomic_dec(&ei->i_prealloc_active);
+ }
+}
+
+static inline void ext4_mb_pa_free(struct ext4_prealloc_space *pa)
+{
+ BUG_ON(!pa);
+ BUG_ON(atomic_read(&pa->pa_count));
+ BUG_ON(pa->pa_deleted == 0);
+ kmem_cache_free(ext4_pspace_cachep, pa);
+}
+
+static void ext4_mb_pa_callback(struct rcu_head *head)
+{
+ struct ext4_prealloc_space *pa;
+
+ pa = container_of(head, struct ext4_prealloc_space, u.pa_rcu);
+ ext4_mb_pa_free(pa);
+}
+
+/*
+ * drops a reference to preallocated space descriptor
+ * if this was the last reference and the space is consumed
+ */
+static void ext4_mb_put_pa(struct ext4_allocation_context *ac,
+ struct super_block *sb, struct ext4_prealloc_space *pa)
+{
+ ext4_group_t grp;
+ ext4_fsblk_t grp_blk;
+ struct ext4_inode_info *ei = EXT4_I(ac->ac_inode);
+
+ /* in this short window concurrent discard can set pa_deleted */
+ spin_lock(&pa->pa_lock);
+ if (!atomic_dec_and_test(&pa->pa_count) || pa->pa_free != 0) {
+ spin_unlock(&pa->pa_lock);
+ return;
+ }
+
+ if (pa->pa_deleted == 1) {
+ spin_unlock(&pa->pa_lock);
+ return;
+ }
+
+ ext4_mb_mark_pa_deleted(sb, pa);
+ spin_unlock(&pa->pa_lock);
+
+ grp_blk = pa->pa_pstart;
+ /*
+ * If doing group-based preallocation, pa_pstart may be in the
+ * next group when pa is used up
+ */
+ if (pa->pa_type == MB_GROUP_PA)
+ grp_blk--;
+
+ grp = ext4_get_group_number(sb, grp_blk);
+
+ /*
+ * possible race:
+ *
+ * P1 (buddy init) P2 (regular allocation)
+ * find block B in PA
+ * copy on-disk bitmap to buddy
+ * mark B in on-disk bitmap
+ * drop PA from group
+ * mark all PAs in buddy
+ *
+ * thus, P1 initializes buddy with B available. to prevent this
+ * we make "copy" and "mark all PAs" atomic and serialize "drop PA"
+ * against that pair
+ */
+ ext4_lock_group(sb, grp);
+ list_del(&pa->pa_group_list);
+ ext4_unlock_group(sb, grp);
+
+ if (pa->pa_type == MB_INODE_PA) {
+ write_lock(pa->pa_node_lock.inode_lock);
+ rb_erase(&pa->pa_node.inode_node, &ei->i_prealloc_node);
+ write_unlock(pa->pa_node_lock.inode_lock);
+ ext4_mb_pa_free(pa);
+ } else {
+ spin_lock(pa->pa_node_lock.lg_lock);
+ list_del_rcu(&pa->pa_node.lg_list);
+ spin_unlock(pa->pa_node_lock.lg_lock);
+ call_rcu(&(pa)->u.pa_rcu, ext4_mb_pa_callback);
+ }
+}
+
+static void ext4_mb_pa_rb_insert(struct rb_root *root, struct rb_node *new)
+{
+ struct rb_node **iter = &root->rb_node, *parent = NULL;
+ struct ext4_prealloc_space *iter_pa, *new_pa;
+ ext4_lblk_t iter_start, new_start;
+
+ while (*iter) {
+ iter_pa = rb_entry(*iter, struct ext4_prealloc_space,
+ pa_node.inode_node);
+ new_pa = rb_entry(new, struct ext4_prealloc_space,
+ pa_node.inode_node);
+ iter_start = iter_pa->pa_lstart;
+ new_start = new_pa->pa_lstart;
+
+ parent = *iter;
+ if (new_start < iter_start)
+ iter = &((*iter)->rb_left);
+ else
+ iter = &((*iter)->rb_right);
+ }
+
+ rb_link_node(new, parent, iter);
+ rb_insert_color(new, root);
+}
+
+/*
+ * creates new preallocated space for given inode
+ */
+static noinline_for_stack void
+ext4_mb_new_inode_pa(struct ext4_allocation_context *ac)
+{
+ struct super_block *sb = ac->ac_sb;
+ struct ext4_sb_info *sbi = EXT4_SB(sb);
+ struct ext4_prealloc_space *pa;
+ struct ext4_group_info *grp;
+ struct ext4_inode_info *ei;
+
+ /* preallocate only when found space is larger then requested */
+ BUG_ON(ac->ac_o_ex.fe_len >= ac->ac_b_ex.fe_len);
+ BUG_ON(ac->ac_status != AC_STATUS_FOUND);
+ BUG_ON(!S_ISREG(ac->ac_inode->i_mode));
+ BUG_ON(ac->ac_pa == NULL);
+
+ pa = ac->ac_pa;
+
+ if (ac->ac_b_ex.fe_len < ac->ac_orig_goal_len) {
+ struct ext4_free_extent ex = {
+ .fe_logical = ac->ac_g_ex.fe_logical,
+ .fe_len = ac->ac_orig_goal_len,
+ };
+ loff_t orig_goal_end = extent_logical_end(sbi, &ex);
+ loff_t o_ex_end = extent_logical_end(sbi, &ac->ac_o_ex);
+
+ /*
+ * We can't allocate as much as normalizer wants, so we try
+ * to get proper lstart to cover the original request, except
+ * when the goal doesn't cover the original request as below:
+ *
+ * orig_ex:2045/2055(10), isize:8417280 -> normalized:0/2048
+ * best_ex:0/200(200) -> adjusted: 1848/2048(200)
+ */
+ BUG_ON(ac->ac_g_ex.fe_logical > ac->ac_o_ex.fe_logical);
+ BUG_ON(ac->ac_g_ex.fe_len < ac->ac_o_ex.fe_len);
+
+ /*
+ * Use the below logic for adjusting best extent as it keeps
+ * fragmentation in check while ensuring logical range of best
+ * extent doesn't overflow out of goal extent:
+ *
+ * 1. Check if best ex can be kept at end of goal (before
+ * cr_best_avail trimmed it) and still cover original start
+ * 2. Else, check if best ex can be kept at start of goal and
+ * still cover original end
+ * 3. Else, keep the best ex at start of original request.
+ */
+ ex.fe_len = ac->ac_b_ex.fe_len;
+
+ ex.fe_logical = orig_goal_end - EXT4_C2B(sbi, ex.fe_len);
+ if (ac->ac_o_ex.fe_logical >= ex.fe_logical)
+ goto adjust_bex;
+
+ ex.fe_logical = ac->ac_g_ex.fe_logical;
+ if (o_ex_end <= extent_logical_end(sbi, &ex))
+ goto adjust_bex;
+
+ ex.fe_logical = ac->ac_o_ex.fe_logical;
+adjust_bex:
+ ac->ac_b_ex.fe_logical = ex.fe_logical;
+
+ BUG_ON(ac->ac_o_ex.fe_logical < ac->ac_b_ex.fe_logical);
+ BUG_ON(extent_logical_end(sbi, &ex) > orig_goal_end);
+ }
+
+ pa->pa_lstart = ac->ac_b_ex.fe_logical;
+ pa->pa_pstart = ext4_grp_offs_to_block(sb, &ac->ac_b_ex);
+ pa->pa_len = ac->ac_b_ex.fe_len;
+ pa->pa_free = pa->pa_len;
+ spin_lock_init(&pa->pa_lock);
+ INIT_LIST_HEAD(&pa->pa_group_list);
+ pa->pa_deleted = 0;
+ pa->pa_type = MB_INODE_PA;
+
+ mb_debug(sb, "new inode pa %p: %llu/%d for %u\n", pa, pa->pa_pstart,
+ pa->pa_len, pa->pa_lstart);
+ trace_ext4_mb_new_inode_pa(ac, pa);
+
+ atomic_add(pa->pa_free, &sbi->s_mb_preallocated);
+ ext4_mb_use_inode_pa(ac, pa);
+
+ ei = EXT4_I(ac->ac_inode);
+ grp = ext4_get_group_info(sb, ac->ac_b_ex.fe_group);
+ if (!grp)
+ return;
+
+ pa->pa_node_lock.inode_lock = &ei->i_prealloc_lock;
+ pa->pa_inode = ac->ac_inode;
+
+ list_add(&pa->pa_group_list, &grp->bb_prealloc_list);
+
+ write_lock(pa->pa_node_lock.inode_lock);
+ ext4_mb_pa_rb_insert(&ei->i_prealloc_node, &pa->pa_node.inode_node);
+ write_unlock(pa->pa_node_lock.inode_lock);
+ atomic_inc(&ei->i_prealloc_active);
+}
+
+/*
+ * creates new preallocated space for locality group inodes belongs to
+ */
+static noinline_for_stack void
+ext4_mb_new_group_pa(struct ext4_allocation_context *ac)
+{
+ struct super_block *sb = ac->ac_sb;
+ struct ext4_locality_group *lg;
+ struct ext4_prealloc_space *pa;
+ struct ext4_group_info *grp;
+
+ /* preallocate only when found space is larger then requested */
+ BUG_ON(ac->ac_o_ex.fe_len >= ac->ac_b_ex.fe_len);
+ BUG_ON(ac->ac_status != AC_STATUS_FOUND);
+ BUG_ON(!S_ISREG(ac->ac_inode->i_mode));
+ BUG_ON(ac->ac_pa == NULL);
+
+ pa = ac->ac_pa;
+
+ pa->pa_pstart = ext4_grp_offs_to_block(sb, &ac->ac_b_ex);
+ pa->pa_lstart = pa->pa_pstart;
+ pa->pa_len = ac->ac_b_ex.fe_len;
+ pa->pa_free = pa->pa_len;
+ spin_lock_init(&pa->pa_lock);
+ INIT_LIST_HEAD(&pa->pa_node.lg_list);
+ INIT_LIST_HEAD(&pa->pa_group_list);
+ pa->pa_deleted = 0;
+ pa->pa_type = MB_GROUP_PA;
+
+ mb_debug(sb, "new group pa %p: %llu/%d for %u\n", pa, pa->pa_pstart,
+ pa->pa_len, pa->pa_lstart);
+ trace_ext4_mb_new_group_pa(ac, pa);
+
+ ext4_mb_use_group_pa(ac, pa);
+ atomic_add(pa->pa_free, &EXT4_SB(sb)->s_mb_preallocated);
+
+ grp = ext4_get_group_info(sb, ac->ac_b_ex.fe_group);
+ if (!grp)
+ return;
+ lg = ac->ac_lg;
+ BUG_ON(lg == NULL);
+
+ pa->pa_node_lock.lg_lock = &lg->lg_prealloc_lock;
+ pa->pa_inode = NULL;
+
+ list_add(&pa->pa_group_list, &grp->bb_prealloc_list);
+
+ /*
+ * We will later add the new pa to the right bucket
+ * after updating the pa_free in ext4_mb_release_context
+ */
+}
+
+static void ext4_mb_new_preallocation(struct ext4_allocation_context *ac)
+{
+ if (ac->ac_flags & EXT4_MB_HINT_GROUP_ALLOC)
+ ext4_mb_new_group_pa(ac);
+ else
+ ext4_mb_new_inode_pa(ac);
+}
+
+/*
+ * finds all unused blocks in on-disk bitmap, frees them in
+ * in-core bitmap and buddy.
+ * @pa must be unlinked from inode and group lists, so that
+ * nobody else can find/use it.
+ * the caller MUST hold group/inode locks.
+ * TODO: optimize the case when there are no in-core structures yet
+ */
+static noinline_for_stack void
+ext4_mb_release_inode_pa(struct ext4_buddy *e4b, struct buffer_head *bitmap_bh,
+ struct ext4_prealloc_space *pa)
+{
+ struct super_block *sb = e4b->bd_sb;
+ struct ext4_sb_info *sbi = EXT4_SB(sb);
+ unsigned int end;
+ unsigned int next;
+ ext4_group_t group;
+ ext4_grpblk_t bit;
+ unsigned long long grp_blk_start;
+ int free = 0;
+
+ BUG_ON(pa->pa_deleted == 0);
+ ext4_get_group_no_and_offset(sb, pa->pa_pstart, &group, &bit);
+ grp_blk_start = pa->pa_pstart - EXT4_C2B(sbi, bit);
+ BUG_ON(group != e4b->bd_group && pa->pa_len != 0);
+ end = bit + pa->pa_len;
+
+ while (bit < end) {
+ bit = mb_find_next_zero_bit(bitmap_bh->b_data, end, bit);
+ if (bit >= end)
+ break;
+ next = mb_find_next_bit(bitmap_bh->b_data, end, bit);
+ mb_debug(sb, "free preallocated %u/%u in group %u\n",
+ (unsigned) ext4_group_first_block_no(sb, group) + bit,
+ (unsigned) next - bit, (unsigned) group);
+ free += next - bit;
+
+ trace_ext4_mballoc_discard(sb, NULL, group, bit, next - bit);
+ trace_ext4_mb_release_inode_pa(pa, (grp_blk_start +
+ EXT4_C2B(sbi, bit)),
+ next - bit);
+ mb_free_blocks(pa->pa_inode, e4b, bit, next - bit);
+ bit = next + 1;
+ }
+ if (free != pa->pa_free) {
+ ext4_msg(e4b->bd_sb, KERN_CRIT,
+ "pa %p: logic %lu, phys. %lu, len %d",
+ pa, (unsigned long) pa->pa_lstart,
+ (unsigned long) pa->pa_pstart,
+ pa->pa_len);
+ ext4_grp_locked_error(sb, group, 0, 0, "free %u, pa_free %u",
+ free, pa->pa_free);
+ /*
+ * pa is already deleted so we use the value obtained
+ * from the bitmap and continue.
+ */
+ }
+ atomic_add(free, &sbi->s_mb_discarded);
+}
+
+static noinline_for_stack void
+ext4_mb_release_group_pa(struct ext4_buddy *e4b,
+ struct ext4_prealloc_space *pa)
+{
+ struct super_block *sb = e4b->bd_sb;
+ ext4_group_t group;
+ ext4_grpblk_t bit;
+
+ trace_ext4_mb_release_group_pa(sb, pa);
+ BUG_ON(pa->pa_deleted == 0);
+ ext4_get_group_no_and_offset(sb, pa->pa_pstart, &group, &bit);
+ if (unlikely(group != e4b->bd_group && pa->pa_len != 0)) {
+ ext4_warning(sb, "bad group: expected %u, group %u, pa_start %llu",
+ e4b->bd_group, group, pa->pa_pstart);
+ return;
+ }
+ mb_free_blocks(pa->pa_inode, e4b, bit, pa->pa_len);
+ atomic_add(pa->pa_len, &EXT4_SB(sb)->s_mb_discarded);
+ trace_ext4_mballoc_discard(sb, NULL, group, bit, pa->pa_len);
+}
+
+/*
+ * releases all preallocations in given group
+ *
+ * first, we need to decide discard policy:
+ * - when do we discard
+ * 1) ENOSPC
+ * - how many do we discard
+ * 1) how many requested
+ */
+static noinline_for_stack int
+ext4_mb_discard_group_preallocations(struct super_block *sb,
+ ext4_group_t group, int *busy)
+{
+ struct ext4_group_info *grp = ext4_get_group_info(sb, group);
+ struct buffer_head *bitmap_bh = NULL;
+ struct ext4_prealloc_space *pa, *tmp;
+ LIST_HEAD(list);
+ struct ext4_buddy e4b;
+ struct ext4_inode_info *ei;
+ int err;
+ int free = 0;
+
+ if (!grp)
+ return 0;
+ mb_debug(sb, "discard preallocation for group %u\n", group);
+ if (list_empty(&grp->bb_prealloc_list))
+ goto out_dbg;
+
+ bitmap_bh = ext4_read_block_bitmap(sb, group);
+ if (IS_ERR(bitmap_bh)) {
+ err = PTR_ERR(bitmap_bh);
+ ext4_error_err(sb, -err,
+ "Error %d reading block bitmap for %u",
+ err, group);
+ goto out_dbg;
+ }
+
+ err = ext4_mb_load_buddy(sb, group, &e4b);
+ if (err) {
+ ext4_warning(sb, "Error %d loading buddy information for %u",
+ err, group);
+ put_bh(bitmap_bh);
+ goto out_dbg;
+ }
+
+ ext4_lock_group(sb, group);
+ list_for_each_entry_safe(pa, tmp,
+ &grp->bb_prealloc_list, pa_group_list) {
+ spin_lock(&pa->pa_lock);
+ if (atomic_read(&pa->pa_count)) {
+ spin_unlock(&pa->pa_lock);
+ *busy = 1;
+ continue;
+ }
+ if (pa->pa_deleted) {
+ spin_unlock(&pa->pa_lock);
+ continue;
+ }
+
+ /* seems this one can be freed ... */
+ ext4_mb_mark_pa_deleted(sb, pa);
+
+ if (!free)
+ this_cpu_inc(discard_pa_seq);
+
+ /* we can trust pa_free ... */
+ free += pa->pa_free;
+
+ spin_unlock(&pa->pa_lock);
+
+ list_del(&pa->pa_group_list);
+ list_add(&pa->u.pa_tmp_list, &list);
+ }
+
+ /* now free all selected PAs */
+ list_for_each_entry_safe(pa, tmp, &list, u.pa_tmp_list) {
+
+ /* remove from object (inode or locality group) */
+ if (pa->pa_type == MB_GROUP_PA) {
+ spin_lock(pa->pa_node_lock.lg_lock);
+ list_del_rcu(&pa->pa_node.lg_list);
+ spin_unlock(pa->pa_node_lock.lg_lock);
+ } else {
+ write_lock(pa->pa_node_lock.inode_lock);
+ ei = EXT4_I(pa->pa_inode);
+ rb_erase(&pa->pa_node.inode_node, &ei->i_prealloc_node);
+ write_unlock(pa->pa_node_lock.inode_lock);
+ }
+
+ list_del(&pa->u.pa_tmp_list);
+
+ if (pa->pa_type == MB_GROUP_PA) {
+ ext4_mb_release_group_pa(&e4b, pa);
+ call_rcu(&(pa)->u.pa_rcu, ext4_mb_pa_callback);
+ } else {
+ ext4_mb_release_inode_pa(&e4b, bitmap_bh, pa);
+ ext4_mb_pa_free(pa);
+ }
+ }
+
+ ext4_unlock_group(sb, group);
+ ext4_mb_unload_buddy(&e4b);
+ put_bh(bitmap_bh);
+out_dbg:
+ mb_debug(sb, "discarded (%d) blocks preallocated for group %u bb_free (%d)\n",
+ free, group, grp->bb_free);
+ return free;
+}
+
+/*
+ * releases all non-used preallocated blocks for given inode
+ *
+ * It's important to discard preallocations under i_data_sem
+ * We don't want another block to be served from the prealloc
+ * space when we are discarding the inode prealloc space.
+ *
+ * FIXME!! Make sure it is valid at all the call sites
+ */
+void ext4_discard_preallocations(struct inode *inode)
+{
+ struct ext4_inode_info *ei = EXT4_I(inode);
+ struct super_block *sb = inode->i_sb;
+ struct buffer_head *bitmap_bh = NULL;
+ struct ext4_prealloc_space *pa, *tmp;
+ ext4_group_t group = 0;
+ LIST_HEAD(list);
+ struct ext4_buddy e4b;
+ struct rb_node *iter;
+ int err;
+
+ if (!S_ISREG(inode->i_mode))
+ return;
+
+ if (EXT4_SB(sb)->s_mount_state & EXT4_FC_REPLAY)
+ return;
+
+ mb_debug(sb, "discard preallocation for inode %lu\n",
+ inode->i_ino);
+ trace_ext4_discard_preallocations(inode,
+ atomic_read(&ei->i_prealloc_active));
+
+repeat:
+ /* first, collect all pa's in the inode */
+ write_lock(&ei->i_prealloc_lock);
+ for (iter = rb_first(&ei->i_prealloc_node); iter;
+ iter = rb_next(iter)) {
+ pa = rb_entry(iter, struct ext4_prealloc_space,
+ pa_node.inode_node);
+ BUG_ON(pa->pa_node_lock.inode_lock != &ei->i_prealloc_lock);
+
+ spin_lock(&pa->pa_lock);
+ if (atomic_read(&pa->pa_count)) {
+ /* this shouldn't happen often - nobody should
+ * use preallocation while we're discarding it */
+ spin_unlock(&pa->pa_lock);
+ write_unlock(&ei->i_prealloc_lock);
+ ext4_msg(sb, KERN_ERR,
+ "uh-oh! used pa while discarding");
+ WARN_ON(1);
+ schedule_timeout_uninterruptible(HZ);
+ goto repeat;
+
+ }
+ if (pa->pa_deleted == 0) {
+ ext4_mb_mark_pa_deleted(sb, pa);
+ spin_unlock(&pa->pa_lock);
+ rb_erase(&pa->pa_node.inode_node, &ei->i_prealloc_node);
+ list_add(&pa->u.pa_tmp_list, &list);
+ continue;
+ }
+
+ /* someone is deleting pa right now */
+ spin_unlock(&pa->pa_lock);
+ write_unlock(&ei->i_prealloc_lock);
+
+ /* we have to wait here because pa_deleted
+ * doesn't mean pa is already unlinked from
+ * the list. as we might be called from
+ * ->clear_inode() the inode will get freed
+ * and concurrent thread which is unlinking
+ * pa from inode's list may access already
+ * freed memory, bad-bad-bad */
+
+ /* XXX: if this happens too often, we can
+ * add a flag to force wait only in case
+ * of ->clear_inode(), but not in case of
+ * regular truncate */
+ schedule_timeout_uninterruptible(HZ);
+ goto repeat;
+ }
+ write_unlock(&ei->i_prealloc_lock);
+
+ list_for_each_entry_safe(pa, tmp, &list, u.pa_tmp_list) {
+ BUG_ON(pa->pa_type != MB_INODE_PA);
+ group = ext4_get_group_number(sb, pa->pa_pstart);
+
+ err = ext4_mb_load_buddy_gfp(sb, group, &e4b,
+ GFP_NOFS|__GFP_NOFAIL);
+ if (err) {
+ ext4_error_err(sb, -err, "Error %d loading buddy information for %u",
+ err, group);
+ continue;
+ }
+
+ bitmap_bh = ext4_read_block_bitmap(sb, group);
+ if (IS_ERR(bitmap_bh)) {
+ err = PTR_ERR(bitmap_bh);
+ ext4_error_err(sb, -err, "Error %d reading block bitmap for %u",
+ err, group);
+ ext4_mb_unload_buddy(&e4b);
+ continue;
+ }
+
+ ext4_lock_group(sb, group);
+ list_del(&pa->pa_group_list);
+ ext4_mb_release_inode_pa(&e4b, bitmap_bh, pa);
+ ext4_unlock_group(sb, group);
+
+ ext4_mb_unload_buddy(&e4b);
+ put_bh(bitmap_bh);
+
+ list_del(&pa->u.pa_tmp_list);
+ ext4_mb_pa_free(pa);
+ }
+}
+
+static int ext4_mb_pa_alloc(struct ext4_allocation_context *ac)
+{
+ struct ext4_prealloc_space *pa;
+
+ BUG_ON(ext4_pspace_cachep == NULL);
+ pa = kmem_cache_zalloc(ext4_pspace_cachep, GFP_NOFS);
+ if (!pa)
+ return -ENOMEM;
+ atomic_set(&pa->pa_count, 1);
+ ac->ac_pa = pa;
+ return 0;
+}
+
+static void ext4_mb_pa_put_free(struct ext4_allocation_context *ac)
+{
+ struct ext4_prealloc_space *pa = ac->ac_pa;
+
+ BUG_ON(!pa);
+ ac->ac_pa = NULL;
+ WARN_ON(!atomic_dec_and_test(&pa->pa_count));
+ /*
+ * current function is only called due to an error or due to
+ * len of found blocks < len of requested blocks hence the PA has not
+ * been added to grp->bb_prealloc_list. So we don't need to lock it
+ */
+ pa->pa_deleted = 1;
+ ext4_mb_pa_free(pa);
+}
+
+#ifdef CONFIG_EXT4_DEBUG
+static inline void ext4_mb_show_pa(struct super_block *sb)
+{
+ ext4_group_t i, ngroups;
+
+ if (ext4_emergency_state(sb))
+ return;
+
+ ngroups = ext4_get_groups_count(sb);
+ mb_debug(sb, "groups: ");
+ for (i = 0; i < ngroups; i++) {
+ struct ext4_group_info *grp = ext4_get_group_info(sb, i);
+ struct ext4_prealloc_space *pa;
+ ext4_grpblk_t start;
+ struct list_head *cur;
+
+ if (!grp)
+ continue;
+ ext4_lock_group(sb, i);
+ list_for_each(cur, &grp->bb_prealloc_list) {
+ pa = list_entry(cur, struct ext4_prealloc_space,
+ pa_group_list);
+ spin_lock(&pa->pa_lock);
+ ext4_get_group_no_and_offset(sb, pa->pa_pstart,
+ NULL, &start);
+ spin_unlock(&pa->pa_lock);
+ mb_debug(sb, "PA:%u:%d:%d\n", i, start,
+ pa->pa_len);
+ }
+ ext4_unlock_group(sb, i);
+ mb_debug(sb, "%u: %d/%d\n", i, grp->bb_free,
+ grp->bb_fragments);
+ }
+}
+
+static void ext4_mb_show_ac(struct ext4_allocation_context *ac)
+{
+ struct super_block *sb = ac->ac_sb;
+
+ if (ext4_emergency_state(sb))
+ return;
+
+ mb_debug(sb, "Can't allocate:"
+ " Allocation context details:");
+ mb_debug(sb, "status %u flags 0x%x",
+ ac->ac_status, ac->ac_flags);
+ mb_debug(sb, "orig %lu/%lu/%lu@%lu, "
+ "goal %lu/%lu/%lu@%lu, "
+ "best %lu/%lu/%lu@%lu cr %d",
+ (unsigned long)ac->ac_o_ex.fe_group,
+ (unsigned long)ac->ac_o_ex.fe_start,
+ (unsigned long)ac->ac_o_ex.fe_len,
+ (unsigned long)ac->ac_o_ex.fe_logical,
+ (unsigned long)ac->ac_g_ex.fe_group,
+ (unsigned long)ac->ac_g_ex.fe_start,
+ (unsigned long)ac->ac_g_ex.fe_len,
+ (unsigned long)ac->ac_g_ex.fe_logical,
+ (unsigned long)ac->ac_b_ex.fe_group,
+ (unsigned long)ac->ac_b_ex.fe_start,
+ (unsigned long)ac->ac_b_ex.fe_len,
+ (unsigned long)ac->ac_b_ex.fe_logical,
+ (int)ac->ac_criteria);
+ mb_debug(sb, "%u found", ac->ac_found);
+ mb_debug(sb, "used pa: %s, ", str_yes_no(ac->ac_pa));
+ if (ac->ac_pa)
+ mb_debug(sb, "pa_type %s\n", ac->ac_pa->pa_type == MB_GROUP_PA ?
+ "group pa" : "inode pa");
+ ext4_mb_show_pa(sb);
+}
+#else
+static inline void ext4_mb_show_pa(struct super_block *sb)
+{
+}
+static inline void ext4_mb_show_ac(struct ext4_allocation_context *ac)
+{
+ ext4_mb_show_pa(ac->ac_sb);
+}
+#endif
+
+/*
+ * We use locality group preallocation for small size file. The size of the
+ * file is determined by the current size or the resulting size after
+ * allocation which ever is larger
+ *
+ * One can tune this size via /sys/fs/ext4/<partition>/mb_stream_req
+ */
+static void ext4_mb_group_or_file(struct ext4_allocation_context *ac)
+{
+ struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
+ int bsbits = ac->ac_sb->s_blocksize_bits;
+ loff_t size, isize;
+ bool inode_pa_eligible, group_pa_eligible;
+
+ if (!(ac->ac_flags & EXT4_MB_HINT_DATA))
+ return;
+
+ if (unlikely(ac->ac_flags & EXT4_MB_HINT_GOAL_ONLY))
+ return;
+
+ group_pa_eligible = sbi->s_mb_group_prealloc > 0;
+ inode_pa_eligible = true;
+ size = extent_logical_end(sbi, &ac->ac_o_ex);
+ isize = (i_size_read(ac->ac_inode) + ac->ac_sb->s_blocksize - 1)
+ >> bsbits;
+
+ /* No point in using inode preallocation for closed files */
+ if ((size == isize) && !ext4_fs_is_busy(sbi) &&
+ !inode_is_open_for_write(ac->ac_inode))
+ inode_pa_eligible = false;
+
+ size = max(size, isize);
+ /* Don't use group allocation for large files */
+ if (size > sbi->s_mb_stream_request)
+ group_pa_eligible = false;
+
+ if (!group_pa_eligible) {
+ if (inode_pa_eligible)
+ ac->ac_flags |= EXT4_MB_STREAM_ALLOC;
+ else
+ ac->ac_flags |= EXT4_MB_HINT_NOPREALLOC;
+ return;
+ }
+
+ BUG_ON(ac->ac_lg != NULL);
+ /*
+ * locality group prealloc space are per cpu. The reason for having
+ * per cpu locality group is to reduce the contention between block
+ * request from multiple CPUs.
+ */
+ ac->ac_lg = raw_cpu_ptr(sbi->s_locality_groups);
+
+ /* we're going to use group allocation */
+ ac->ac_flags |= EXT4_MB_HINT_GROUP_ALLOC;
+
+ /* serialize all allocations in the group */
+ mutex_lock(&ac->ac_lg->lg_mutex);
+}
+
+static noinline_for_stack void
+ext4_mb_initialize_context(struct ext4_allocation_context *ac,
+ struct ext4_allocation_request *ar)
+{
+ struct super_block *sb = ar->inode->i_sb;
+ struct ext4_sb_info *sbi = EXT4_SB(sb);
+ struct ext4_super_block *es = sbi->s_es;
+ ext4_group_t group;
+ unsigned int len;
+ ext4_fsblk_t goal;
+ ext4_grpblk_t block;
+
+ /* we can't allocate > group size */
+ len = ar->len;
+
+ /* just a dirty hack to filter too big requests */
+ if (len >= EXT4_CLUSTERS_PER_GROUP(sb))
+ len = EXT4_CLUSTERS_PER_GROUP(sb);
+
+ /* start searching from the goal */
+ goal = ar->goal;
+ if (goal < le32_to_cpu(es->s_first_data_block) ||
+ goal >= ext4_blocks_count(es))
+ goal = le32_to_cpu(es->s_first_data_block);
+ ext4_get_group_no_and_offset(sb, goal, &group, &block);
+
+ /* set up allocation goals */
+ ac->ac_b_ex.fe_logical = EXT4_LBLK_CMASK(sbi, ar->logical);
+ ac->ac_status = AC_STATUS_CONTINUE;
+ ac->ac_sb = sb;
+ ac->ac_inode = ar->inode;
+ ac->ac_o_ex.fe_logical = ac->ac_b_ex.fe_logical;
+ ac->ac_o_ex.fe_group = group;
+ ac->ac_o_ex.fe_start = block;
+ ac->ac_o_ex.fe_len = len;
+ ac->ac_g_ex = ac->ac_o_ex;
+ ac->ac_orig_goal_len = ac->ac_g_ex.fe_len;
+ ac->ac_flags = ar->flags;
+
+ /* we have to define context: we'll work with a file or
+ * locality group. this is a policy, actually */
+ ext4_mb_group_or_file(ac);
+
+ mb_debug(sb, "init ac: %u blocks @ %u, goal %u, flags 0x%x, 2^%d, "
+ "left: %u/%u, right %u/%u to %swritable\n",
+ (unsigned) ar->len, (unsigned) ar->logical,
+ (unsigned) ar->goal, ac->ac_flags, ac->ac_2order,
+ (unsigned) ar->lleft, (unsigned) ar->pleft,
+ (unsigned) ar->lright, (unsigned) ar->pright,
+ inode_is_open_for_write(ar->inode) ? "" : "non-");
+}
+
+static noinline_for_stack void
+ext4_mb_discard_lg_preallocations(struct super_block *sb,
+ struct ext4_locality_group *lg,
+ int order, int total_entries)
+{
+ ext4_group_t group = 0;
+ struct ext4_buddy e4b;
+ LIST_HEAD(discard_list);
+ struct ext4_prealloc_space *pa, *tmp;
+
+ mb_debug(sb, "discard locality group preallocation\n");
+
+ spin_lock(&lg->lg_prealloc_lock);
+ list_for_each_entry_rcu(pa, &lg->lg_prealloc_list[order],
+ pa_node.lg_list,
+ lockdep_is_held(&lg->lg_prealloc_lock)) {
+ spin_lock(&pa->pa_lock);
+ if (atomic_read(&pa->pa_count)) {
+ /*
+ * This is the pa that we just used
+ * for block allocation. So don't
+ * free that
+ */
+ spin_unlock(&pa->pa_lock);
+ continue;
+ }
+ if (pa->pa_deleted) {
+ spin_unlock(&pa->pa_lock);
+ continue;
+ }
+ /* only lg prealloc space */
+ BUG_ON(pa->pa_type != MB_GROUP_PA);
+
+ /* seems this one can be freed ... */
+ ext4_mb_mark_pa_deleted(sb, pa);
+ spin_unlock(&pa->pa_lock);
+
+ list_del_rcu(&pa->pa_node.lg_list);
+ list_add(&pa->u.pa_tmp_list, &discard_list);
+
+ total_entries--;
+ if (total_entries <= 5) {
+ /*
+ * we want to keep only 5 entries
+ * allowing it to grow to 8. This
+ * mak sure we don't call discard
+ * soon for this list.
+ */
+ break;
+ }
+ }
+ spin_unlock(&lg->lg_prealloc_lock);
+
+ list_for_each_entry_safe(pa, tmp, &discard_list, u.pa_tmp_list) {
+ int err;
+
+ group = ext4_get_group_number(sb, pa->pa_pstart);
+ err = ext4_mb_load_buddy_gfp(sb, group, &e4b,
+ GFP_NOFS|__GFP_NOFAIL);
+ if (err) {
+ ext4_error_err(sb, -err, "Error %d loading buddy information for %u",
+ err, group);
+ continue;
+ }
+ ext4_lock_group(sb, group);
+ list_del(&pa->pa_group_list);
+ ext4_mb_release_group_pa(&e4b, pa);
+ ext4_unlock_group(sb, group);
+
+ ext4_mb_unload_buddy(&e4b);
+ list_del(&pa->u.pa_tmp_list);
+ call_rcu(&(pa)->u.pa_rcu, ext4_mb_pa_callback);
+ }
+}
+
+/*
+ * We have incremented pa_count. So it cannot be freed at this
+ * point. Also we hold lg_mutex. So no parallel allocation is
+ * possible from this lg. That means pa_free cannot be updated.
+ *
+ * A parallel ext4_mb_discard_group_preallocations is possible.
+ * which can cause the lg_prealloc_list to be updated.
+ */
+
+static void ext4_mb_add_n_trim(struct ext4_allocation_context *ac)
+{
+ int order, added = 0, lg_prealloc_count = 1;
+ struct super_block *sb = ac->ac_sb;
+ struct ext4_locality_group *lg = ac->ac_lg;
+ struct ext4_prealloc_space *tmp_pa, *pa = ac->ac_pa;
+
+ order = fls(pa->pa_free) - 1;
+ if (order > PREALLOC_TB_SIZE - 1)
+ /* The max size of hash table is PREALLOC_TB_SIZE */
+ order = PREALLOC_TB_SIZE - 1;
+ /* Add the prealloc space to lg */
+ spin_lock(&lg->lg_prealloc_lock);
+ list_for_each_entry_rcu(tmp_pa, &lg->lg_prealloc_list[order],
+ pa_node.lg_list,
+ lockdep_is_held(&lg->lg_prealloc_lock)) {
+ spin_lock(&tmp_pa->pa_lock);
+ if (tmp_pa->pa_deleted) {
+ spin_unlock(&tmp_pa->pa_lock);
+ continue;
+ }
+ if (!added && pa->pa_free < tmp_pa->pa_free) {
+ /* Add to the tail of the previous entry */
+ list_add_tail_rcu(&pa->pa_node.lg_list,
+ &tmp_pa->pa_node.lg_list);
+ added = 1;
+ /*
+ * we want to count the total
+ * number of entries in the list
+ */
+ }
+ spin_unlock(&tmp_pa->pa_lock);
+ lg_prealloc_count++;
+ }
+ if (!added)
+ list_add_tail_rcu(&pa->pa_node.lg_list,
+ &lg->lg_prealloc_list[order]);
+ spin_unlock(&lg->lg_prealloc_lock);
+
+ /* Now trim the list to be not more than 8 elements */
+ if (lg_prealloc_count > 8)
+ ext4_mb_discard_lg_preallocations(sb, lg,
+ order, lg_prealloc_count);
+}
+
+/*
+ * release all resource we used in allocation
+ */
+static void ext4_mb_release_context(struct ext4_allocation_context *ac)
+{
+ struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
+ struct ext4_prealloc_space *pa = ac->ac_pa;
+ if (pa) {
+ if (pa->pa_type == MB_GROUP_PA) {
+ /* see comment in ext4_mb_use_group_pa() */
+ spin_lock(&pa->pa_lock);
+ pa->pa_pstart += EXT4_C2B(sbi, ac->ac_b_ex.fe_len);
+ pa->pa_lstart += EXT4_C2B(sbi, ac->ac_b_ex.fe_len);
+ pa->pa_free -= ac->ac_b_ex.fe_len;
+ pa->pa_len -= ac->ac_b_ex.fe_len;
+ spin_unlock(&pa->pa_lock);
+
+ /*
+ * We want to add the pa to the right bucket.
+ * Remove it from the list and while adding
+ * make sure the list to which we are adding
+ * doesn't grow big.
+ */
+ if (likely(pa->pa_free)) {
+ spin_lock(pa->pa_node_lock.lg_lock);
+ list_del_rcu(&pa->pa_node.lg_list);
+ spin_unlock(pa->pa_node_lock.lg_lock);
+ ext4_mb_add_n_trim(ac);
+ }
+ }
+
+ ext4_mb_put_pa(ac, ac->ac_sb, pa);
+ }
+ if (ac->ac_bitmap_folio)
+ folio_put(ac->ac_bitmap_folio);
+ if (ac->ac_buddy_folio)
+ folio_put(ac->ac_buddy_folio);
+ if (ac->ac_flags & EXT4_MB_HINT_GROUP_ALLOC)
+ mutex_unlock(&ac->ac_lg->lg_mutex);
+ ext4_mb_collect_stats(ac);
+}
+
+static int ext4_mb_discard_preallocations(struct super_block *sb, int needed)
+{
+ ext4_group_t i, ngroups = ext4_get_groups_count(sb);
+ int ret;
+ int freed = 0, busy = 0;
+ int retry = 0;
+
+ trace_ext4_mb_discard_preallocations(sb, needed);
+
+ if (needed == 0)
+ needed = EXT4_CLUSTERS_PER_GROUP(sb) + 1;
+ repeat:
+ for (i = 0; i < ngroups && needed > 0; i++) {
+ ret = ext4_mb_discard_group_preallocations(sb, i, &busy);
+ freed += ret;
+ needed -= ret;
+ cond_resched();
+ }
+
+ if (needed > 0 && busy && ++retry < 3) {
+ busy = 0;
+ goto repeat;
+ }
+
+ return freed;
+}
+
+static bool ext4_mb_discard_preallocations_should_retry(struct super_block *sb,
+ struct ext4_allocation_context *ac, u64 *seq)
+{
+ int freed;
+ u64 seq_retry = 0;
+ bool ret = false;
+
+ freed = ext4_mb_discard_preallocations(sb, ac->ac_o_ex.fe_len);
+ if (freed) {
+ ret = true;
+ goto out_dbg;
+ }
+ seq_retry = ext4_get_discard_pa_seq_sum();
+ if (!(ac->ac_flags & EXT4_MB_STRICT_CHECK) || seq_retry != *seq) {
+ ac->ac_flags |= EXT4_MB_STRICT_CHECK;
+ *seq = seq_retry;
+ ret = true;
+ }
+
+out_dbg:
+ mb_debug(sb, "freed %d, retry ? %s\n", freed, str_yes_no(ret));
+ return ret;
+}
+
+/*
+ * Simple allocator for Ext4 fast commit replay path. It searches for blocks
+ * linearly starting at the goal block and also excludes the blocks which
+ * are going to be in use after fast commit replay.
+ */
+static ext4_fsblk_t
+ext4_mb_new_blocks_simple(struct ext4_allocation_request *ar, int *errp)
+{
+ struct buffer_head *bitmap_bh;
+ struct super_block *sb = ar->inode->i_sb;
+ struct ext4_sb_info *sbi = EXT4_SB(sb);
+ ext4_group_t group, nr;
+ ext4_grpblk_t blkoff;
+ ext4_grpblk_t max = EXT4_CLUSTERS_PER_GROUP(sb);
+ ext4_grpblk_t i = 0;
+ ext4_fsblk_t goal, block;
+ struct ext4_super_block *es = sbi->s_es;
+
+ goal = ar->goal;
+ if (goal < le32_to_cpu(es->s_first_data_block) ||
+ goal >= ext4_blocks_count(es))
+ goal = le32_to_cpu(es->s_first_data_block);
+
+ ar->len = 0;
+ ext4_get_group_no_and_offset(sb, goal, &group, &blkoff);
+ for (nr = ext4_get_groups_count(sb); nr > 0; nr--) {
+ bitmap_bh = ext4_read_block_bitmap(sb, group);
+ if (IS_ERR(bitmap_bh)) {
+ *errp = PTR_ERR(bitmap_bh);
+ pr_warn("Failed to read block bitmap\n");
+ return 0;
+ }
+
+ while (1) {
+ i = mb_find_next_zero_bit(bitmap_bh->b_data, max,
+ blkoff);
+ if (i >= max)
+ break;
+ if (ext4_fc_replay_check_excluded(sb,
+ ext4_group_first_block_no(sb, group) +
+ EXT4_C2B(sbi, i))) {
+ blkoff = i + 1;
+ } else
+ break;
+ }
+ brelse(bitmap_bh);
+ if (i < max)
+ break;
+
+ if (++group >= ext4_get_groups_count(sb))
+ group = 0;
+
+ blkoff = 0;
+ }
+
+ if (i >= max) {
+ *errp = -ENOSPC;
+ return 0;
+ }
+
+ block = ext4_group_first_block_no(sb, group) + EXT4_C2B(sbi, i);
+ ext4_mb_mark_bb(sb, block, 1, true);
+ ar->len = 1;
+
+ *errp = 0;
+ return block;
+}
+
+/*
+ * Main entry point into mballoc to allocate blocks
+ * it tries to use preallocation first, then falls back
+ * to usual allocation
+ */
+ext4_fsblk_t ext4_mb_new_blocks(handle_t *handle,
+ struct ext4_allocation_request *ar, int *errp)
+{
+ struct ext4_allocation_context *ac = NULL;
+ struct ext4_sb_info *sbi;
+ struct super_block *sb;
+ ext4_fsblk_t block = 0;
+ unsigned int inquota = 0;
+ unsigned int reserv_clstrs = 0;
+ int retries = 0;
+ u64 seq;
+
+ might_sleep();
+ sb = ar->inode->i_sb;
+ sbi = EXT4_SB(sb);
+
+ trace_ext4_request_blocks(ar);
+ if (sbi->s_mount_state & EXT4_FC_REPLAY)
+ return ext4_mb_new_blocks_simple(ar, errp);
+
+ /* Allow to use superuser reservation for quota file */
+ if (ext4_is_quota_file(ar->inode))
+ ar->flags |= EXT4_MB_USE_ROOT_BLOCKS;
+
+ if ((ar->flags & EXT4_MB_DELALLOC_RESERVED) == 0) {
+ /* Without delayed allocation we need to verify
+ * there is enough free blocks to do block allocation
+ * and verify allocation doesn't exceed the quota limits.
+ */
+ while (ar->len &&
+ ext4_claim_free_clusters(sbi, ar->len, ar->flags)) {
+
+ /* let others to free the space */
+ cond_resched();
+ ar->len = ar->len >> 1;
+ }
+ if (!ar->len) {
+ ext4_mb_show_pa(sb);
+ *errp = -ENOSPC;
+ return 0;
+ }
+ reserv_clstrs = ar->len;
+ if (ar->flags & EXT4_MB_USE_ROOT_BLOCKS) {
+ dquot_alloc_block_nofail(ar->inode,
+ EXT4_C2B(sbi, ar->len));
+ } else {
+ while (ar->len &&
+ dquot_alloc_block(ar->inode,
+ EXT4_C2B(sbi, ar->len))) {
+
+ ar->flags |= EXT4_MB_HINT_NOPREALLOC;
+ ar->len--;
+ }
+ }
+ inquota = ar->len;
+ if (ar->len == 0) {
+ *errp = -EDQUOT;
+ goto out;
+ }
+ }
+
+ ac = kmem_cache_zalloc(ext4_ac_cachep, GFP_NOFS);
+ if (!ac) {
+ ar->len = 0;
+ *errp = -ENOMEM;
+ goto out;
+ }
+
+ ext4_mb_initialize_context(ac, ar);
+
+ ac->ac_op = EXT4_MB_HISTORY_PREALLOC;
+ seq = this_cpu_read(discard_pa_seq);
+ if (!ext4_mb_use_preallocated(ac)) {
+ ac->ac_op = EXT4_MB_HISTORY_ALLOC;
+ ext4_mb_normalize_request(ac, ar);
+
+ *errp = ext4_mb_pa_alloc(ac);
+ if (*errp)
+ goto errout;
+repeat:
+ /* allocate space in core */
+ *errp = ext4_mb_regular_allocator(ac);
+ /*
+ * pa allocated above is added to grp->bb_prealloc_list only
+ * when we were able to allocate some block i.e. when
+ * ac->ac_status == AC_STATUS_FOUND.
+ * And error from above mean ac->ac_status != AC_STATUS_FOUND
+ * So we have to free this pa here itself.
+ */
+ if (*errp) {
+ ext4_mb_pa_put_free(ac);
+ ext4_discard_allocated_blocks(ac);
+ goto errout;
+ }
+ if (ac->ac_status == AC_STATUS_FOUND &&
+ ac->ac_o_ex.fe_len >= ac->ac_f_ex.fe_len)
+ ext4_mb_pa_put_free(ac);
+ }
+ if (likely(ac->ac_status == AC_STATUS_FOUND)) {
+ *errp = ext4_mb_mark_diskspace_used(ac, handle, reserv_clstrs);
+ if (*errp) {
+ ext4_discard_allocated_blocks(ac);
+ goto errout;
+ } else {
+ block = ext4_grp_offs_to_block(sb, &ac->ac_b_ex);
+ ar->len = ac->ac_b_ex.fe_len;
+ }
+ } else {
+ if (++retries < 3 &&
+ ext4_mb_discard_preallocations_should_retry(sb, ac, &seq))
+ goto repeat;
+ /*
+ * If block allocation fails then the pa allocated above
+ * needs to be freed here itself.
+ */
+ ext4_mb_pa_put_free(ac);
+ *errp = -ENOSPC;
+ }
+
+ if (*errp) {
+errout:
+ ac->ac_b_ex.fe_len = 0;
+ ar->len = 0;
+ ext4_mb_show_ac(ac);
+ }
+ ext4_mb_release_context(ac);
+ kmem_cache_free(ext4_ac_cachep, ac);
+out:
+ if (inquota && ar->len < inquota)
+ dquot_free_block(ar->inode, EXT4_C2B(sbi, inquota - ar->len));
+ if (!ar->len) {
+ if ((ar->flags & EXT4_MB_DELALLOC_RESERVED) == 0)
+ /* release all the reserved blocks if non delalloc */
+ percpu_counter_sub(&sbi->s_dirtyclusters_counter,
+ reserv_clstrs);
+ }
+
+ trace_ext4_allocate_blocks(ar, (unsigned long long)block);
+
+ return block;
+}
+
+/*
+ * We can merge two free data extents only if the physical blocks
+ * are contiguous, AND the extents were freed by the same transaction,
+ * AND the blocks are associated with the same group.
+ */
+static inline bool
+ext4_freed_extents_can_be_merged(struct ext4_free_data *entry1,
+ struct ext4_free_data *entry2)
+{
+ if (entry1->efd_tid != entry2->efd_tid)
+ return false;
+ if (entry1->efd_start_cluster + entry1->efd_count !=
+ entry2->efd_start_cluster)
+ return false;
+ if (WARN_ON_ONCE(entry1->efd_group != entry2->efd_group))
+ return false;
+ return true;
+}
+
+static inline void
+ext4_merge_freed_extents(struct ext4_sb_info *sbi, struct rb_root *root,
+ struct ext4_free_data *entry1,
+ struct ext4_free_data *entry2)
+{
+ entry1->efd_count += entry2->efd_count;
+ spin_lock(&sbi->s_md_lock);
+ list_del(&entry2->efd_list);
+ spin_unlock(&sbi->s_md_lock);
+ rb_erase(&entry2->efd_node, root);
+ kmem_cache_free(ext4_free_data_cachep, entry2);
+}
+
+static inline void
+ext4_try_merge_freed_extent_prev(struct ext4_sb_info *sbi, struct rb_root *root,
+ struct ext4_free_data *entry)
+{
+ struct ext4_free_data *prev;
+ struct rb_node *node;
+
+ node = rb_prev(&entry->efd_node);
+ if (!node)
+ return;
+
+ prev = rb_entry(node, struct ext4_free_data, efd_node);
+ if (ext4_freed_extents_can_be_merged(prev, entry))
+ ext4_merge_freed_extents(sbi, root, prev, entry);
+}
+
+static inline void
+ext4_try_merge_freed_extent_next(struct ext4_sb_info *sbi, struct rb_root *root,
+ struct ext4_free_data *entry)
+{
+ struct ext4_free_data *next;
+ struct rb_node *node;
+
+ node = rb_next(&entry->efd_node);
+ if (!node)
+ return;
+
+ next = rb_entry(node, struct ext4_free_data, efd_node);
+ if (ext4_freed_extents_can_be_merged(entry, next))
+ ext4_merge_freed_extents(sbi, root, entry, next);
+}
+
+static noinline_for_stack void
+ext4_mb_free_metadata(handle_t *handle, struct ext4_buddy *e4b,
+ struct ext4_free_data *new_entry)
+{
+ ext4_group_t group = e4b->bd_group;
+ ext4_grpblk_t cluster;
+ ext4_grpblk_t clusters = new_entry->efd_count;
+ struct ext4_free_data *entry = NULL;
+ struct ext4_group_info *db = e4b->bd_info;
+ struct super_block *sb = e4b->bd_sb;
+ struct ext4_sb_info *sbi = EXT4_SB(sb);
+ struct rb_root *root = &db->bb_free_root;
+ struct rb_node **n = &root->rb_node;
+ struct rb_node *parent = NULL, *new_node;
+
+ BUG_ON(!ext4_handle_valid(handle));
+ BUG_ON(e4b->bd_bitmap_folio == NULL);
+ BUG_ON(e4b->bd_buddy_folio == NULL);
+
+ new_node = &new_entry->efd_node;
+ cluster = new_entry->efd_start_cluster;
+
+ if (!*n) {
+ /* first free block exent. We need to
+ protect buddy cache from being freed,
+ * otherwise we'll refresh it from
+ * on-disk bitmap and lose not-yet-available
+ * blocks */
+ folio_get(e4b->bd_buddy_folio);
+ folio_get(e4b->bd_bitmap_folio);
+ }
+ while (*n) {
+ parent = *n;
+ entry = rb_entry(parent, struct ext4_free_data, efd_node);
+ if (cluster < entry->efd_start_cluster)
+ n = &(*n)->rb_left;
+ else if (cluster >= (entry->efd_start_cluster + entry->efd_count))
+ n = &(*n)->rb_right;
+ else {
+ ext4_grp_locked_error(sb, group, 0,
+ ext4_group_first_block_no(sb, group) +
+ EXT4_C2B(sbi, cluster),
+ "Block already on to-be-freed list");
+ kmem_cache_free(ext4_free_data_cachep, new_entry);
+ return;
+ }
+ }
+
+ atomic_add(clusters, &sbi->s_mb_free_pending);
+ if (!entry)
+ goto insert;
+
+ /* Now try to see the extent can be merged to prev and next */
+ if (ext4_freed_extents_can_be_merged(new_entry, entry)) {
+ entry->efd_start_cluster = cluster;
+ entry->efd_count += new_entry->efd_count;
+ kmem_cache_free(ext4_free_data_cachep, new_entry);
+ ext4_try_merge_freed_extent_prev(sbi, root, entry);
+ return;
+ }
+ if (ext4_freed_extents_can_be_merged(entry, new_entry)) {
+ entry->efd_count += new_entry->efd_count;
+ kmem_cache_free(ext4_free_data_cachep, new_entry);
+ ext4_try_merge_freed_extent_next(sbi, root, entry);
+ return;
+ }
+insert:
+ rb_link_node(new_node, parent, n);
+ rb_insert_color(new_node, root);
+
+ spin_lock(&sbi->s_md_lock);
+ list_add_tail(&new_entry->efd_list, &sbi->s_freed_data_list[new_entry->efd_tid & 1]);
+ spin_unlock(&sbi->s_md_lock);
+}
+
+static void ext4_free_blocks_simple(struct inode *inode, ext4_fsblk_t block,
+ unsigned long count)
+{
+ struct super_block *sb = inode->i_sb;
+ ext4_group_t group;
+ ext4_grpblk_t blkoff;
+
+ ext4_get_group_no_and_offset(sb, block, &group, &blkoff);
+ ext4_mb_mark_context(NULL, sb, false, group, blkoff, count,
+ EXT4_MB_BITMAP_MARKED_CHECK |
+ EXT4_MB_SYNC_UPDATE,
+ NULL);
+}
+
+/**
+ * ext4_mb_clear_bb() -- helper function for freeing blocks.
+ * Used by ext4_free_blocks()
+ * @handle: handle for this transaction
+ * @inode: inode
+ * @block: starting physical block to be freed
+ * @count: number of blocks to be freed
+ * @flags: flags used by ext4_free_blocks
+ */
+static void ext4_mb_clear_bb(handle_t *handle, struct inode *inode,
+ ext4_fsblk_t block, unsigned long count,
+ int flags)
+{
+ struct super_block *sb = inode->i_sb;
+ struct ext4_group_info *grp;
+ unsigned int overflow;
+ ext4_grpblk_t bit;
+ ext4_group_t block_group;
+ struct ext4_sb_info *sbi;
+ struct ext4_buddy e4b;
+ unsigned int count_clusters;
+ int err = 0;
+ int mark_flags = 0;
+ ext4_grpblk_t changed;
+
+ sbi = EXT4_SB(sb);
+
+ if (!(flags & EXT4_FREE_BLOCKS_VALIDATED) &&
+ !ext4_inode_block_valid(inode, block, count)) {
+ ext4_error(sb, "Freeing blocks in system zone - "
+ "Block = %llu, count = %lu", block, count);
+ /* err = 0. ext4_std_error should be a no op */
+ goto error_out;
+ }
+ flags |= EXT4_FREE_BLOCKS_VALIDATED;
+
+do_more:
+ overflow = 0;
+ ext4_get_group_no_and_offset(sb, block, &block_group, &bit);
+
+ grp = ext4_get_group_info(sb, block_group);
+ if (unlikely(!grp || EXT4_MB_GRP_BBITMAP_CORRUPT(grp)))
+ return;
+
+ /*
+ * Check to see if we are freeing blocks across a group
+ * boundary.
+ */
+ if (EXT4_C2B(sbi, bit) + count > EXT4_BLOCKS_PER_GROUP(sb)) {
+ overflow = EXT4_C2B(sbi, bit) + count -
+ EXT4_BLOCKS_PER_GROUP(sb);
+ count -= overflow;
+ /* The range changed so it's no longer validated */
+ flags &= ~EXT4_FREE_BLOCKS_VALIDATED;
+ }
+ count_clusters = EXT4_NUM_B2C(sbi, count);
+ trace_ext4_mballoc_free(sb, inode, block_group, bit, count_clusters);
+
+ /* __GFP_NOFAIL: retry infinitely, ignore TIF_MEMDIE and memcg limit. */
+ err = ext4_mb_load_buddy_gfp(sb, block_group, &e4b,
+ GFP_NOFS|__GFP_NOFAIL);
+ if (err)
+ goto error_out;
+
+ if (!(flags & EXT4_FREE_BLOCKS_VALIDATED) &&
+ !ext4_inode_block_valid(inode, block, count)) {
+ ext4_error(sb, "Freeing blocks in system zone - "
+ "Block = %llu, count = %lu", block, count);
+ /* err = 0. ext4_std_error should be a no op */
+ goto error_clean;
+ }
+
+#ifdef AGGRESSIVE_CHECK
+ mark_flags |= EXT4_MB_BITMAP_MARKED_CHECK;
+#endif
+ err = ext4_mb_mark_context(handle, sb, false, block_group, bit,
+ count_clusters, mark_flags, &changed);
+
+
+ if (err && changed == 0)
+ goto error_clean;
+
+#ifdef AGGRESSIVE_CHECK
+ BUG_ON(changed != count_clusters);
+#endif
+
+ /*
+ * We need to make sure we don't reuse the freed block until after the
+ * transaction is committed. We make an exception if the inode is to be
+ * written in writeback mode since writeback mode has weak data
+ * consistency guarantees.
+ */
+ if (ext4_handle_valid(handle) &&
+ ((flags & EXT4_FREE_BLOCKS_METADATA) ||
+ !ext4_should_writeback_data(inode))) {
+ struct ext4_free_data *new_entry;
+ /*
+ * We use __GFP_NOFAIL because ext4_free_blocks() is not allowed
+ * to fail.
+ */
+ new_entry = kmem_cache_alloc(ext4_free_data_cachep,
+ GFP_NOFS|__GFP_NOFAIL);
+ new_entry->efd_start_cluster = bit;
+ new_entry->efd_group = block_group;
+ new_entry->efd_count = count_clusters;
+ new_entry->efd_tid = handle->h_transaction->t_tid;
+
+ ext4_lock_group(sb, block_group);
+ ext4_mb_free_metadata(handle, &e4b, new_entry);
+ } else {
+ if (test_opt(sb, DISCARD)) {
+ err = ext4_issue_discard(sb, block_group, bit,
+ count_clusters);
+ /*
+ * Ignore EOPNOTSUPP error. This is consistent with
+ * what happens when using journal.
+ */
+ if (err == -EOPNOTSUPP)
+ err = 0;
+ if (err)
+ ext4_msg(sb, KERN_WARNING, "discard request in"
+ " group:%u block:%d count:%lu failed"
+ " with %d", block_group, bit, count,
+ err);
+ }
+
+ EXT4_MB_GRP_CLEAR_TRIMMED(e4b.bd_info);
+
+ ext4_lock_group(sb, block_group);
+ mb_free_blocks(inode, &e4b, bit, count_clusters);
+ }
+
+ ext4_unlock_group(sb, block_group);
+
+ /*
+ * on a bigalloc file system, defer the s_freeclusters_counter
+ * update to the caller (ext4_remove_space and friends) so they
+ * can determine if a cluster freed here should be rereserved
+ */
+ if (!(flags & EXT4_FREE_BLOCKS_RERESERVE_CLUSTER)) {
+ if (!(flags & EXT4_FREE_BLOCKS_NO_QUOT_UPDATE))
+ dquot_free_block(inode, EXT4_C2B(sbi, count_clusters));
+ percpu_counter_add(&sbi->s_freeclusters_counter,
+ count_clusters);
+ }
+
+ if (overflow && !err) {
+ block += count;
+ count = overflow;
+ ext4_mb_unload_buddy(&e4b);
+ /* The range changed so it's no longer validated */
+ flags &= ~EXT4_FREE_BLOCKS_VALIDATED;
+ goto do_more;
+ }
+
+error_clean:
+ ext4_mb_unload_buddy(&e4b);
+error_out:
+ ext4_std_error(sb, err);
+}
+
+/**
+ * ext4_free_blocks() -- Free given blocks and update quota
+ * @handle: handle for this transaction
+ * @inode: inode
+ * @bh: optional buffer of the block to be freed
+ * @block: starting physical block to be freed
+ * @count: number of blocks to be freed
+ * @flags: flags used by ext4_free_blocks
+ */
+void ext4_free_blocks(handle_t *handle, struct inode *inode,
+ struct buffer_head *bh, ext4_fsblk_t block,
+ unsigned long count, int flags)
+{
+ struct super_block *sb = inode->i_sb;
+ unsigned int overflow;
+ struct ext4_sb_info *sbi;
+
+ sbi = EXT4_SB(sb);
+
+ if (bh) {
+ if (block)
+ BUG_ON(block != bh->b_blocknr);
+ else
+ block = bh->b_blocknr;
+ }
+
+ if (sbi->s_mount_state & EXT4_FC_REPLAY) {
+ ext4_free_blocks_simple(inode, block, EXT4_NUM_B2C(sbi, count));
+ return;
+ }
+
+ might_sleep();
+
+ if (!(flags & EXT4_FREE_BLOCKS_VALIDATED) &&
+ !ext4_inode_block_valid(inode, block, count)) {
+ ext4_error(sb, "Freeing blocks not in datazone - "
+ "block = %llu, count = %lu", block, count);
+ return;
+ }
+ flags |= EXT4_FREE_BLOCKS_VALIDATED;
+
+ ext4_debug("freeing block %llu\n", block);
+ trace_ext4_free_blocks(inode, block, count, flags);
+
+ if (bh && (flags & EXT4_FREE_BLOCKS_FORGET)) {
+ BUG_ON(count > 1);
+
+ ext4_forget(handle, flags & EXT4_FREE_BLOCKS_METADATA,
+ inode, bh, block);
+ }
+
+ /*
+ * If the extent to be freed does not begin on a cluster
+ * boundary, we need to deal with partial clusters at the
+ * beginning and end of the extent. Normally we will free
+ * blocks at the beginning or the end unless we are explicitly
+ * requested to avoid doing so.
+ */
+ overflow = EXT4_PBLK_COFF(sbi, block);
+ if (overflow) {
+ if (flags & EXT4_FREE_BLOCKS_NOFREE_FIRST_CLUSTER) {
+ overflow = sbi->s_cluster_ratio - overflow;
+ block += overflow;
+ if (count > overflow)
+ count -= overflow;
+ else
+ return;
+ } else {
+ block -= overflow;
+ count += overflow;
+ }
+ /* The range changed so it's no longer validated */
+ flags &= ~EXT4_FREE_BLOCKS_VALIDATED;
+ }
+ overflow = EXT4_LBLK_COFF(sbi, count);
+ if (overflow) {
+ if (flags & EXT4_FREE_BLOCKS_NOFREE_LAST_CLUSTER) {
+ if (count > overflow)
+ count -= overflow;
+ else
+ return;
+ } else
+ count += sbi->s_cluster_ratio - overflow;
+ /* The range changed so it's no longer validated */
+ flags &= ~EXT4_FREE_BLOCKS_VALIDATED;
+ }
+
+ if (!bh && (flags & EXT4_FREE_BLOCKS_FORGET)) {
+ int i;
+ int is_metadata = flags & EXT4_FREE_BLOCKS_METADATA;
+
+ for (i = 0; i < count; i++) {
+ cond_resched();
+ if (is_metadata)
+ bh = sb_find_get_block_nonatomic(inode->i_sb,
+ block + i);
+ ext4_forget(handle, is_metadata, inode, bh, block + i);
+ }
+ }
+
+ ext4_mb_clear_bb(handle, inode, block, count, flags);
+}
+
+/**
+ * ext4_group_add_blocks() -- Add given blocks to an existing group
+ * @handle: handle to this transaction
+ * @sb: super block
+ * @block: start physical block to add to the block group
+ * @count: number of blocks to free
+ *
+ * This marks the blocks as free in the bitmap and buddy.
+ */
+int ext4_group_add_blocks(handle_t *handle, struct super_block *sb,
+ ext4_fsblk_t block, unsigned long count)
+{
+ ext4_group_t block_group;
+ ext4_grpblk_t bit;
+ struct ext4_sb_info *sbi = EXT4_SB(sb);
+ struct ext4_buddy e4b;
+ int err = 0;
+ ext4_fsblk_t first_cluster = EXT4_B2C(sbi, block);
+ ext4_fsblk_t last_cluster = EXT4_B2C(sbi, block + count - 1);
+ unsigned long cluster_count = last_cluster - first_cluster + 1;
+ ext4_grpblk_t changed;
+
+ ext4_debug("Adding block(s) %llu-%llu\n", block, block + count - 1);
+
+ if (cluster_count == 0)
+ return 0;
+
+ ext4_get_group_no_and_offset(sb, block, &block_group, &bit);
+ /*
+ * Check to see if we are freeing blocks across a group
+ * boundary.
+ */
+ if (bit + cluster_count > EXT4_CLUSTERS_PER_GROUP(sb)) {
+ ext4_warning(sb, "too many blocks added to group %u",
+ block_group);
+ err = -EINVAL;
+ goto error_out;
+ }
+
+ err = ext4_mb_load_buddy(sb, block_group, &e4b);
+ if (err)
+ goto error_out;
+
+ if (!ext4_sb_block_valid(sb, NULL, block, count)) {
+ ext4_error(sb, "Adding blocks in system zones - "
+ "Block = %llu, count = %lu",
+ block, count);
+ err = -EINVAL;
+ goto error_clean;
+ }
+
+ err = ext4_mb_mark_context(handle, sb, false, block_group, bit,
+ cluster_count, EXT4_MB_BITMAP_MARKED_CHECK,
+ &changed);
+ if (err && changed == 0)
+ goto error_clean;
+
+ if (changed != cluster_count)
+ ext4_error(sb, "bit already cleared in group %u", block_group);
+
+ ext4_lock_group(sb, block_group);
+ mb_free_blocks(NULL, &e4b, bit, cluster_count);
+ ext4_unlock_group(sb, block_group);
+ percpu_counter_add(&sbi->s_freeclusters_counter,
+ changed);
+
+error_clean:
+ ext4_mb_unload_buddy(&e4b);
+error_out:
+ ext4_std_error(sb, err);
+ return err;
+}
+
+/**
+ * ext4_trim_extent -- function to TRIM one single free extent in the group
+ * @sb: super block for the file system
+ * @start: starting block of the free extent in the alloc. group
+ * @count: number of blocks to TRIM
+ * @e4b: ext4 buddy for the group
+ *
+ * Trim "count" blocks starting at "start" in the "group". To assure that no
+ * one will allocate those blocks, mark it as used in buddy bitmap. This must
+ * be called with under the group lock.
+ */
+static int ext4_trim_extent(struct super_block *sb,
+ int start, int count, struct ext4_buddy *e4b)
+__releases(bitlock)
+__acquires(bitlock)
+{
+ struct ext4_free_extent ex;
+ ext4_group_t group = e4b->bd_group;
+ int ret = 0;
+
+ trace_ext4_trim_extent(sb, group, start, count);
+
+ assert_spin_locked(ext4_group_lock_ptr(sb, group));
+
+ ex.fe_start = start;
+ ex.fe_group = group;
+ ex.fe_len = count;
+
+ /*
+ * Mark blocks used, so no one can reuse them while
+ * being trimmed.
+ */
+ mb_mark_used(e4b, &ex);
+ ext4_unlock_group(sb, group);
+ ret = ext4_issue_discard(sb, group, start, count);
+ ext4_lock_group(sb, group);
+ mb_free_blocks(NULL, e4b, start, ex.fe_len);
+ return ret;
+}
+
+static ext4_grpblk_t ext4_last_grp_cluster(struct super_block *sb,
+ ext4_group_t grp)
+{
+ unsigned long nr_clusters_in_group;
+
+ if (grp < (ext4_get_groups_count(sb) - 1))
+ nr_clusters_in_group = EXT4_CLUSTERS_PER_GROUP(sb);
+ else
+ nr_clusters_in_group = (ext4_blocks_count(EXT4_SB(sb)->s_es) -
+ ext4_group_first_block_no(sb, grp))
+ >> EXT4_CLUSTER_BITS(sb);
+
+ return nr_clusters_in_group - 1;
+}
+
+static bool ext4_trim_interrupted(void)
+{
+ return fatal_signal_pending(current) || freezing(current);
+}
+
+static int ext4_try_to_trim_range(struct super_block *sb,
+ struct ext4_buddy *e4b, ext4_grpblk_t start,
+ ext4_grpblk_t max, ext4_grpblk_t minblocks)
+__acquires(ext4_group_lock_ptr(sb, e4b->bd_group))
+__releases(ext4_group_lock_ptr(sb, e4b->bd_group))
+{
+ ext4_grpblk_t next, count, free_count, last, origin_start;
+ bool set_trimmed = false;
+ void *bitmap;
+
+ if (unlikely(EXT4_MB_GRP_BBITMAP_CORRUPT(e4b->bd_info)))
+ return 0;
+
+ last = ext4_last_grp_cluster(sb, e4b->bd_group);
+ bitmap = e4b->bd_bitmap;
+ if (start == 0 && max >= last)
+ set_trimmed = true;
+ origin_start = start;
+ start = max(e4b->bd_info->bb_first_free, start);
+ count = 0;
+ free_count = 0;
+
+ while (start <= max) {
+ start = mb_find_next_zero_bit(bitmap, max + 1, start);
+ if (start > max)
+ break;
+
+ next = mb_find_next_bit(bitmap, last + 1, start);
+ if (origin_start == 0 && next >= last)
+ set_trimmed = true;
+
+ if ((next - start) >= minblocks) {
+ int ret = ext4_trim_extent(sb, start, next - start, e4b);
+
+ if (ret && ret != -EOPNOTSUPP)
+ return count;
+ count += next - start;
+ }
+ free_count += next - start;
+ start = next + 1;
+
+ if (ext4_trim_interrupted())
+ return count;
+
+ if (need_resched()) {
+ ext4_unlock_group(sb, e4b->bd_group);
+ cond_resched();
+ ext4_lock_group(sb, e4b->bd_group);
+ }
+
+ if ((e4b->bd_info->bb_free - free_count) < minblocks)
+ break;
+ }
+
+ if (set_trimmed)
+ EXT4_MB_GRP_SET_TRIMMED(e4b->bd_info);
+
+ return count;
+}
+
+/**
+ * ext4_trim_all_free -- function to trim all free space in alloc. group
+ * @sb: super block for file system
+ * @group: group to be trimmed
+ * @start: first group block to examine
+ * @max: last group block to examine
+ * @minblocks: minimum extent block count
+ *
+ * ext4_trim_all_free walks through group's block bitmap searching for free
+ * extents. When the free extent is found, mark it as used in group buddy
+ * bitmap. Then issue a TRIM command on this extent and free the extent in
+ * the group buddy bitmap.
+ */
+static ext4_grpblk_t
+ext4_trim_all_free(struct super_block *sb, ext4_group_t group,
+ ext4_grpblk_t start, ext4_grpblk_t max,
+ ext4_grpblk_t minblocks)
+{
+ struct ext4_buddy e4b;
+ int ret;
+
+ trace_ext4_trim_all_free(sb, group, start, max);
+
+ ret = ext4_mb_load_buddy(sb, group, &e4b);
+ if (ret) {
+ ext4_warning(sb, "Error %d loading buddy information for %u",
+ ret, group);
+ return ret;
+ }
+
+ ext4_lock_group(sb, group);
+
+ if (!EXT4_MB_GRP_WAS_TRIMMED(e4b.bd_info) ||
+ minblocks < EXT4_SB(sb)->s_last_trim_minblks)
+ ret = ext4_try_to_trim_range(sb, &e4b, start, max, minblocks);
+ else
+ ret = 0;
+
+ ext4_unlock_group(sb, group);
+ ext4_mb_unload_buddy(&e4b);
+
+ ext4_debug("trimmed %d blocks in the group %d\n",
+ ret, group);
+
+ return ret;
+}
+
+/**
+ * ext4_trim_fs() -- trim ioctl handle function
+ * @sb: superblock for filesystem
+ * @range: fstrim_range structure
+ *
+ * start: First Byte to trim
+ * len: number of Bytes to trim from start
+ * minlen: minimum extent length in Bytes
+ * ext4_trim_fs goes through all allocation groups containing Bytes from
+ * start to start+len. For each such a group ext4_trim_all_free function
+ * is invoked to trim all free space.
+ */
+int ext4_trim_fs(struct super_block *sb, struct fstrim_range *range)
+{
+ unsigned int discard_granularity = bdev_discard_granularity(sb->s_bdev);
+ struct ext4_group_info *grp;
+ ext4_group_t group, first_group, last_group;
+ ext4_grpblk_t cnt = 0, first_cluster, last_cluster;
+ uint64_t start, end, minlen, trimmed = 0;
+ ext4_fsblk_t first_data_blk =
+ le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block);
+ ext4_fsblk_t max_blks = ext4_blocks_count(EXT4_SB(sb)->s_es);
+ int ret = 0;
+
+ start = range->start >> sb->s_blocksize_bits;
+ end = start + (range->len >> sb->s_blocksize_bits) - 1;
+ minlen = EXT4_NUM_B2C(EXT4_SB(sb),
+ range->minlen >> sb->s_blocksize_bits);
+
+ if (minlen > EXT4_CLUSTERS_PER_GROUP(sb) ||
+ start >= max_blks ||
+ range->len < sb->s_blocksize)
+ return -EINVAL;
+ /* No point to try to trim less than discard granularity */
+ if (range->minlen < discard_granularity) {
+ minlen = EXT4_NUM_B2C(EXT4_SB(sb),
+ discard_granularity >> sb->s_blocksize_bits);
+ if (minlen > EXT4_CLUSTERS_PER_GROUP(sb))
+ goto out;
+ }
+ if (end >= max_blks - 1)
+ end = max_blks - 1;
+ if (end <= first_data_blk)
+ goto out;
+ if (start < first_data_blk)
+ start = first_data_blk;
+
+ /* Determine first and last group to examine based on start and end */
+ ext4_get_group_no_and_offset(sb, (ext4_fsblk_t) start,
+ &first_group, &first_cluster);
+ ext4_get_group_no_and_offset(sb, (ext4_fsblk_t) end,
+ &last_group, &last_cluster);
+
+ /* end now represents the last cluster to discard in this group */
+ end = EXT4_CLUSTERS_PER_GROUP(sb) - 1;
+
+ for (group = first_group; group <= last_group; group++) {
+ if (ext4_trim_interrupted())
+ break;
+ grp = ext4_get_group_info(sb, group);
+ if (!grp)
+ continue;
+ /* We only do this if the grp has never been initialized */
+ if (unlikely(EXT4_MB_GRP_NEED_INIT(grp))) {
+ ret = ext4_mb_init_group(sb, group, GFP_NOFS);
+ if (ret)
+ break;
+ }
+
+ /*
+ * For all the groups except the last one, last cluster will
+ * always be EXT4_CLUSTERS_PER_GROUP(sb)-1, so we only need to
+ * change it for the last group, note that last_cluster is
+ * already computed earlier by ext4_get_group_no_and_offset()
+ */
+ if (group == last_group)
+ end = last_cluster;
+ if (grp->bb_free >= minlen) {
+ cnt = ext4_trim_all_free(sb, group, first_cluster,
+ end, minlen);
+ if (cnt < 0) {
+ ret = cnt;
+ break;
+ }
+ trimmed += cnt;
+ }
+
+ /*
+ * For every group except the first one, we are sure
+ * that the first cluster to discard will be cluster #0.
+ */
+ first_cluster = 0;
+ }
+
+ if (!ret)
+ EXT4_SB(sb)->s_last_trim_minblks = minlen;
+
+out:
+ range->len = EXT4_C2B(EXT4_SB(sb), trimmed) << sb->s_blocksize_bits;
+ return ret;
+}
+
+/* Iterate all the free extents in the group. */
+int
+ext4_mballoc_query_range(
+ struct super_block *sb,
+ ext4_group_t group,
+ ext4_grpblk_t first,
+ ext4_grpblk_t end,
+ ext4_mballoc_query_range_fn meta_formatter,
+ ext4_mballoc_query_range_fn formatter,
+ void *priv)
+{
+ void *bitmap;
+ ext4_grpblk_t start, next;
+ struct ext4_buddy e4b;
+ int error;
+
+ error = ext4_mb_load_buddy(sb, group, &e4b);
+ if (error)
+ return error;
+ bitmap = e4b.bd_bitmap;
+
+ ext4_lock_group(sb, group);
+
+ start = max(e4b.bd_info->bb_first_free, first);
+ if (end >= EXT4_CLUSTERS_PER_GROUP(sb))
+ end = EXT4_CLUSTERS_PER_GROUP(sb) - 1;
+ if (meta_formatter && start != first) {
+ if (start > end)
+ start = end;
+ ext4_unlock_group(sb, group);
+ error = meta_formatter(sb, group, first, start - first,
+ priv);
+ if (error)
+ goto out_unload;
+ ext4_lock_group(sb, group);
+ }
+ while (start <= end) {
+ start = mb_find_next_zero_bit(bitmap, end + 1, start);
+ if (start > end)
+ break;
+ next = mb_find_next_bit(bitmap, end + 1, start);
+
+ ext4_unlock_group(sb, group);
+ error = formatter(sb, group, start, next - start, priv);
+ if (error)
+ goto out_unload;
+ ext4_lock_group(sb, group);
+
+ start = next + 1;
+ }
+
+ ext4_unlock_group(sb, group);
+out_unload:
+ ext4_mb_unload_buddy(&e4b);
+
+ return error;
+}
+
+#ifdef CONFIG_EXT4_KUNIT_TESTS
+#include "mballoc-test.c"
+#endif