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+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * linux/include/linux/jbd2.h
+ *
+ * Written by Stephen C. Tweedie <sct@redhat.com>
+ *
+ * Copyright 1998-2000 Red Hat, Inc --- All Rights Reserved
+ *
+ * Definitions for transaction data structures for the buffer cache
+ * filesystem journaling support.
+ */
+
+#ifndef _LINUX_JBD2_H
+#define _LINUX_JBD2_H
+
+/* Allow this file to be included directly into e2fsprogs */
+#ifndef __KERNEL__
+#include "jfs_compat.h"
+#define JBD2_DEBUG
+#else
+
+#include <linux/types.h>
+#include <linux/buffer_head.h>
+#include <linux/journal-head.h>
+#include <linux/stddef.h>
+#include <linux/mutex.h>
+#include <linux/timer.h>
+#include <linux/slab.h>
+#include <linux/bit_spinlock.h>
+#include <linux/blkdev.h>
+#include <linux/crc32c.h>
+#endif
+
+#define journal_oom_retry 1
+
+/*
+ * Define JBD2_PARANIOD_IOFAIL to cause a kernel BUG() if ext4 finds
+ * certain classes of error which can occur due to failed IOs. Under
+ * normal use we want ext4 to continue after such errors, because
+ * hardware _can_ fail, but for debugging purposes when running tests on
+ * known-good hardware we may want to trap these errors.
+ */
+#undef JBD2_PARANOID_IOFAIL
+
+/*
+ * The default maximum commit age, in seconds.
+ */
+#define JBD2_DEFAULT_MAX_COMMIT_AGE 5
+
+#ifdef CONFIG_JBD2_DEBUG
+/*
+ * Define JBD2_EXPENSIVE_CHECKING to enable more expensive internal
+ * consistency checks. By default we don't do this unless
+ * CONFIG_JBD2_DEBUG is on.
+ */
+#define JBD2_EXPENSIVE_CHECKING
+void __jbd2_debug(int level, const char *file, const char *func,
+ unsigned int line, const char *fmt, ...);
+
+#define jbd2_debug(n, fmt, a...) \
+ __jbd2_debug((n), __FILE__, __func__, __LINE__, (fmt), ##a)
+#else
+#define jbd2_debug(n, fmt, a...) no_printk(fmt, ##a)
+#endif
+
+extern void *jbd2_alloc(size_t size, gfp_t flags);
+extern void jbd2_free(void *ptr, size_t size);
+
+#define JBD2_MIN_JOURNAL_BLOCKS 1024
+#define JBD2_DEFAULT_FAST_COMMIT_BLOCKS 256
+
+#ifdef __KERNEL__
+
+/**
+ * typedef handle_t - The handle_t type represents a single atomic update being performed by some process.
+ *
+ * All filesystem modifications made by the process go
+ * through this handle. Recursive operations (such as quota operations)
+ * are gathered into a single update.
+ *
+ * The buffer credits field is used to account for journaled buffers
+ * being modified by the running process. To ensure that there is
+ * enough log space for all outstanding operations, we need to limit the
+ * number of outstanding buffers possible at any time. When the
+ * operation completes, any buffer credits not used are credited back to
+ * the transaction, so that at all times we know how many buffers the
+ * outstanding updates on a transaction might possibly touch.
+ *
+ * This is an opaque datatype.
+ **/
+typedef struct jbd2_journal_handle handle_t; /* Atomic operation type */
+
+
+/**
+ * typedef journal_t - The journal_t maintains all of the journaling state information for a single filesystem.
+ *
+ * journal_t is linked to from the fs superblock structure.
+ *
+ * We use the journal_t to keep track of all outstanding transaction
+ * activity on the filesystem, and to manage the state of the log
+ * writing process.
+ *
+ * This is an opaque datatype.
+ **/
+typedef struct journal_s journal_t; /* Journal control structure */
+#endif
+
+/*
+ * Internal structures used by the logging mechanism:
+ */
+
+#define JBD2_MAGIC_NUMBER 0xc03b3998U /* The first 4 bytes of /dev/random! */
+
+/*
+ * On-disk structures
+ */
+
+/*
+ * Descriptor block types:
+ */
+
+#define JBD2_DESCRIPTOR_BLOCK 1
+#define JBD2_COMMIT_BLOCK 2
+#define JBD2_SUPERBLOCK_V1 3
+#define JBD2_SUPERBLOCK_V2 4
+#define JBD2_REVOKE_BLOCK 5
+
+/*
+ * Standard header for all descriptor blocks:
+ */
+typedef struct journal_header_s
+{
+ __be32 h_magic;
+ __be32 h_blocktype;
+ __be32 h_sequence;
+} journal_header_t;
+
+/*
+ * Checksum types.
+ */
+#define JBD2_CRC32_CHKSUM 1
+#define JBD2_MD5_CHKSUM 2
+#define JBD2_SHA1_CHKSUM 3
+#define JBD2_CRC32C_CHKSUM 4
+
+#define JBD2_CRC32_CHKSUM_SIZE 4
+
+#define JBD2_CHECKSUM_BYTES (32 / sizeof(u32))
+/*
+ * Commit block header for storing transactional checksums:
+ *
+ * NOTE: If FEATURE_COMPAT_CHECKSUM (checksum v1) is set, the h_chksum*
+ * fields are used to store a checksum of the descriptor and data blocks.
+ *
+ * If FEATURE_INCOMPAT_CSUM_V2 (checksum v2) is set, then the h_chksum
+ * field is used to store crc32c(uuid+commit_block). Each journal metadata
+ * block gets its own checksum, and data block checksums are stored in
+ * journal_block_tag (in the descriptor). The other h_chksum* fields are
+ * not used.
+ *
+ * If FEATURE_INCOMPAT_CSUM_V3 is set, the descriptor block uses
+ * journal_block_tag3_t to store a full 32-bit checksum. Everything else
+ * is the same as v2.
+ *
+ * Checksum v1, v2, and v3 are mutually exclusive features.
+ */
+struct commit_header {
+ __be32 h_magic;
+ __be32 h_blocktype;
+ __be32 h_sequence;
+ unsigned char h_chksum_type;
+ unsigned char h_chksum_size;
+ unsigned char h_padding[2];
+ __be32 h_chksum[JBD2_CHECKSUM_BYTES];
+ __be64 h_commit_sec;
+ __be32 h_commit_nsec;
+};
+
+/*
+ * The block tag: used to describe a single buffer in the journal.
+ * t_blocknr_high is only used if INCOMPAT_64BIT is set, so this
+ * raw struct shouldn't be used for pointer math or sizeof() - use
+ * journal_tag_bytes(journal) instead to compute this.
+ */
+typedef struct journal_block_tag3_s
+{
+ __be32 t_blocknr; /* The on-disk block number */
+ __be32 t_flags; /* See below */
+ __be32 t_blocknr_high; /* most-significant high 32bits. */
+ __be32 t_checksum; /* crc32c(uuid+seq+block) */
+} journal_block_tag3_t;
+
+typedef struct journal_block_tag_s
+{
+ __be32 t_blocknr; /* The on-disk block number */
+ __be16 t_checksum; /* truncated crc32c(uuid+seq+block) */
+ __be16 t_flags; /* See below */
+ __be32 t_blocknr_high; /* most-significant high 32bits. */
+} journal_block_tag_t;
+
+/* Tail of descriptor or revoke block, for checksumming */
+struct jbd2_journal_block_tail {
+ __be32 t_checksum; /* crc32c(uuid+descr_block) */
+};
+
+/*
+ * The revoke descriptor: used on disk to describe a series of blocks to
+ * be revoked from the log
+ */
+typedef struct jbd2_journal_revoke_header_s
+{
+ journal_header_t r_header;
+ __be32 r_count; /* Count of bytes used in the block */
+} jbd2_journal_revoke_header_t;
+
+/* Definitions for the journal tag flags word: */
+#define JBD2_FLAG_ESCAPE 1 /* on-disk block is escaped */
+#define JBD2_FLAG_SAME_UUID 2 /* block has same uuid as previous */
+#define JBD2_FLAG_DELETED 4 /* block deleted by this transaction */
+#define JBD2_FLAG_LAST_TAG 8 /* last tag in this descriptor block */
+
+
+/*
+ * The journal superblock. All fields are in big-endian byte order.
+ */
+typedef struct journal_superblock_s
+{
+/* 0x0000 */
+ journal_header_t s_header;
+
+/* 0x000C */
+ /* Static information describing the journal */
+ __be32 s_blocksize; /* journal device blocksize */
+ __be32 s_maxlen; /* total blocks in journal file */
+ __be32 s_first; /* first block of log information */
+
+/* 0x0018 */
+ /* Dynamic information describing the current state of the log */
+ __be32 s_sequence; /* first commit ID expected in log */
+ __be32 s_start; /* blocknr of start of log */
+
+/* 0x0020 */
+ /* Error value, as set by jbd2_journal_abort(). */
+ __be32 s_errno;
+
+/* 0x0024 */
+ /* Remaining fields are only valid in a version-2 superblock */
+ __be32 s_feature_compat; /* compatible feature set */
+ __be32 s_feature_incompat; /* incompatible feature set */
+ __be32 s_feature_ro_compat; /* readonly-compatible feature set */
+/* 0x0030 */
+ __u8 s_uuid[16]; /* 128-bit uuid for journal */
+
+/* 0x0040 */
+ __be32 s_nr_users; /* Nr of filesystems sharing log */
+
+ __be32 s_dynsuper; /* Blocknr of dynamic superblock copy*/
+
+/* 0x0048 */
+ __be32 s_max_transaction; /* Limit of journal blocks per trans.*/
+ __be32 s_max_trans_data; /* Limit of data blocks per trans. */
+
+/* 0x0050 */
+ __u8 s_checksum_type; /* checksum type */
+ __u8 s_padding2[3];
+/* 0x0054 */
+ __be32 s_num_fc_blks; /* Number of fast commit blocks */
+ __be32 s_head; /* blocknr of head of log, only uptodate
+ * while the filesystem is clean */
+/* 0x005C */
+ __u32 s_padding[40];
+ __be32 s_checksum; /* crc32c(superblock) */
+
+/* 0x0100 */
+ __u8 s_users[16*48]; /* ids of all fs'es sharing the log */
+/* 0x0400 */
+} journal_superblock_t;
+
+#define JBD2_FEATURE_COMPAT_CHECKSUM 0x00000001
+
+#define JBD2_FEATURE_INCOMPAT_REVOKE 0x00000001
+#define JBD2_FEATURE_INCOMPAT_64BIT 0x00000002
+#define JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT 0x00000004
+#define JBD2_FEATURE_INCOMPAT_CSUM_V2 0x00000008
+#define JBD2_FEATURE_INCOMPAT_CSUM_V3 0x00000010
+#define JBD2_FEATURE_INCOMPAT_FAST_COMMIT 0x00000020
+
+/* See "journal feature predicate functions" below */
+
+/* Features known to this kernel version: */
+#define JBD2_KNOWN_COMPAT_FEATURES JBD2_FEATURE_COMPAT_CHECKSUM
+#define JBD2_KNOWN_ROCOMPAT_FEATURES 0
+#define JBD2_KNOWN_INCOMPAT_FEATURES (JBD2_FEATURE_INCOMPAT_REVOKE | \
+ JBD2_FEATURE_INCOMPAT_64BIT | \
+ JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT | \
+ JBD2_FEATURE_INCOMPAT_CSUM_V2 | \
+ JBD2_FEATURE_INCOMPAT_CSUM_V3 | \
+ JBD2_FEATURE_INCOMPAT_FAST_COMMIT)
+
+#ifdef __KERNEL__
+
+#include <linux/fs.h>
+#include <linux/sched.h>
+
+enum jbd_state_bits {
+ BH_JBD /* Has an attached ext3 journal_head */
+ = BH_PrivateStart,
+ BH_JWrite, /* Being written to log (@@@ DEBUGGING) */
+ BH_Freed, /* Has been freed (truncated) */
+ BH_Revoked, /* Has been revoked from the log */
+ BH_RevokeValid, /* Revoked flag is valid */
+ BH_JBDDirty, /* Is dirty but journaled */
+ BH_JournalHead, /* Pins bh->b_private and jh->b_bh */
+ BH_Shadow, /* IO on shadow buffer is running */
+ BH_Verified, /* Metadata block has been verified ok */
+ BH_JBDPrivateStart, /* First bit available for private use by FS */
+};
+
+BUFFER_FNS(JBD, jbd)
+BUFFER_FNS(JWrite, jwrite)
+BUFFER_FNS(JBDDirty, jbddirty)
+TAS_BUFFER_FNS(JBDDirty, jbddirty)
+BUFFER_FNS(Revoked, revoked)
+TAS_BUFFER_FNS(Revoked, revoked)
+BUFFER_FNS(RevokeValid, revokevalid)
+TAS_BUFFER_FNS(RevokeValid, revokevalid)
+BUFFER_FNS(Freed, freed)
+BUFFER_FNS(Shadow, shadow)
+BUFFER_FNS(Verified, verified)
+
+static inline struct buffer_head *jh2bh(struct journal_head *jh)
+{
+ return jh->b_bh;
+}
+
+static inline struct journal_head *bh2jh(struct buffer_head *bh)
+{
+ return bh->b_private;
+}
+
+static inline void jbd_lock_bh_journal_head(struct buffer_head *bh)
+{
+ bit_spin_lock(BH_JournalHead, &bh->b_state);
+}
+
+static inline void jbd_unlock_bh_journal_head(struct buffer_head *bh)
+{
+ bit_spin_unlock(BH_JournalHead, &bh->b_state);
+}
+
+#define J_ASSERT(assert) BUG_ON(!(assert))
+
+#define J_ASSERT_BH(bh, expr) J_ASSERT(expr)
+#define J_ASSERT_JH(jh, expr) J_ASSERT(expr)
+
+#if defined(JBD2_PARANOID_IOFAIL)
+#define J_EXPECT(expr, why...) J_ASSERT(expr)
+#define J_EXPECT_BH(bh, expr, why...) J_ASSERT_BH(bh, expr)
+#define J_EXPECT_JH(jh, expr, why...) J_ASSERT_JH(jh, expr)
+#else
+#define __journal_expect(expr, why...) \
+ ({ \
+ int val = (expr); \
+ if (!val) { \
+ printk(KERN_ERR \
+ "JBD2 unexpected failure: %s: %s;\n", \
+ __func__, #expr); \
+ printk(KERN_ERR why "\n"); \
+ } \
+ val; \
+ })
+#define J_EXPECT(expr, why...) __journal_expect(expr, ## why)
+#define J_EXPECT_BH(bh, expr, why...) __journal_expect(expr, ## why)
+#define J_EXPECT_JH(jh, expr, why...) __journal_expect(expr, ## why)
+#endif
+
+/* Flags in jbd_inode->i_flags */
+#define __JI_COMMIT_RUNNING 0
+#define __JI_WRITE_DATA 1
+#define __JI_WAIT_DATA 2
+
+/*
+ * Commit of the inode data in progress. We use this flag to protect us from
+ * concurrent deletion of inode. We cannot use reference to inode for this
+ * since we cannot afford doing last iput() on behalf of kjournald
+ */
+#define JI_COMMIT_RUNNING (1 << __JI_COMMIT_RUNNING)
+/* Write allocated dirty buffers in this inode before commit */
+#define JI_WRITE_DATA (1 << __JI_WRITE_DATA)
+/* Wait for outstanding data writes for this inode before commit */
+#define JI_WAIT_DATA (1 << __JI_WAIT_DATA)
+
+/**
+ * struct jbd2_inode - The jbd_inode type is the structure linking inodes in
+ * ordered mode present in a transaction so that we can sync them during commit.
+ */
+struct jbd2_inode {
+ /**
+ * @i_transaction:
+ *
+ * Which transaction does this inode belong to? Either the running
+ * transaction or the committing one. [j_list_lock]
+ */
+ transaction_t *i_transaction;
+
+ /**
+ * @i_next_transaction:
+ *
+ * Pointer to the running transaction modifying inode's data in case
+ * there is already a committing transaction touching it. [j_list_lock]
+ */
+ transaction_t *i_next_transaction;
+
+ /**
+ * @i_list: List of inodes in the i_transaction [j_list_lock]
+ */
+ struct list_head i_list;
+
+ /**
+ * @i_vfs_inode:
+ *
+ * VFS inode this inode belongs to [constant for lifetime of structure]
+ */
+ struct inode *i_vfs_inode;
+
+ /**
+ * @i_flags: Flags of inode [j_list_lock]
+ */
+ unsigned long i_flags;
+
+ /**
+ * @i_dirty_start:
+ *
+ * Offset in bytes where the dirty range for this inode starts.
+ * [j_list_lock]
+ */
+ loff_t i_dirty_start;
+
+ /**
+ * @i_dirty_end:
+ *
+ * Inclusive offset in bytes where the dirty range for this inode
+ * ends. [j_list_lock]
+ */
+ loff_t i_dirty_end;
+};
+
+struct jbd2_revoke_table_s;
+
+/**
+ * struct jbd2_journal_handle - The jbd2_journal_handle type is the concrete
+ * type associated with handle_t.
+ * @h_transaction: Which compound transaction is this update a part of?
+ * @h_journal: Which journal handle belongs to - used iff h_reserved set.
+ * @h_rsv_handle: Handle reserved for finishing the logical operation.
+ * @h_total_credits: Number of remaining buffers we are allowed to add to
+ * journal. These are dirty buffers and revoke descriptor blocks.
+ * @h_revoke_credits: Number of remaining revoke records available for handle
+ * @h_ref: Reference count on this handle.
+ * @h_err: Field for caller's use to track errors through large fs operations.
+ * @h_sync: Flag for sync-on-close.
+ * @h_reserved: Flag for handle for reserved credits.
+ * @h_aborted: Flag indicating fatal error on handle.
+ * @h_type: For handle statistics.
+ * @h_line_no: For handle statistics.
+ * @h_start_jiffies: Handle Start time.
+ * @h_requested_credits: Holds @h_total_credits after handle is started.
+ * @h_revoke_credits_requested: Holds @h_revoke_credits after handle is started.
+ * @saved_alloc_context: Saved context while transaction is open.
+ **/
+
+/* Docbook can't yet cope with the bit fields, but will leave the documentation
+ * in so it can be fixed later.
+ */
+
+struct jbd2_journal_handle
+{
+ union {
+ transaction_t *h_transaction;
+ /* Which journal handle belongs to - used iff h_reserved set */
+ journal_t *h_journal;
+ };
+
+ handle_t *h_rsv_handle;
+ int h_total_credits;
+ int h_revoke_credits;
+ int h_revoke_credits_requested;
+ int h_ref;
+ int h_err;
+
+ /* Flags [no locking] */
+ unsigned int h_sync: 1;
+ unsigned int h_reserved: 1;
+ unsigned int h_aborted: 1;
+ unsigned int h_type: 8;
+ unsigned int h_line_no: 16;
+
+ unsigned long h_start_jiffies;
+ unsigned int h_requested_credits;
+
+ unsigned int saved_alloc_context;
+};
+
+
+/*
+ * Some stats for checkpoint phase
+ */
+struct transaction_chp_stats_s {
+ unsigned long cs_chp_time;
+ __u32 cs_forced_to_close;
+ __u32 cs_written;
+ __u32 cs_dropped;
+};
+
+/* The transaction_t type is the guts of the journaling mechanism. It
+ * tracks a compound transaction through its various states:
+ *
+ * RUNNING: accepting new updates
+ * LOCKED: Updates still running but we don't accept new ones
+ * RUNDOWN: Updates are tidying up but have finished requesting
+ * new buffers to modify (state not used for now)
+ * FLUSH: All updates complete, but we are still writing to disk
+ * COMMIT: All data on disk, writing commit record
+ * FINISHED: We still have to keep the transaction for checkpointing.
+ *
+ * The transaction keeps track of all of the buffers modified by a
+ * running transaction, and all of the buffers committed but not yet
+ * flushed to home for finished transactions.
+ * (Locking Documentation improved by LockDoc)
+ */
+
+/*
+ * Lock ranking:
+ *
+ * j_list_lock
+ * ->jbd_lock_bh_journal_head() (This is "innermost")
+ *
+ * j_state_lock
+ * ->b_state_lock
+ *
+ * b_state_lock
+ * ->j_list_lock
+ *
+ * j_state_lock
+ * ->j_list_lock (journal_unmap_buffer)
+ *
+ */
+
+struct transaction_s
+{
+ /* Pointer to the journal for this transaction. [no locking] */
+ journal_t *t_journal;
+
+ /* Sequence number for this transaction [no locking] */
+ tid_t t_tid;
+
+ /*
+ * Transaction's current state
+ * [no locking - only kjournald2 alters this]
+ * [j_list_lock] guards transition of a transaction into T_FINISHED
+ * state and subsequent call of __jbd2_journal_drop_transaction()
+ * FIXME: needs barriers
+ * KLUDGE: [use j_state_lock]
+ */
+ enum {
+ T_RUNNING,
+ T_LOCKED,
+ T_SWITCH,
+ T_FLUSH,
+ T_COMMIT,
+ T_COMMIT_DFLUSH,
+ T_COMMIT_JFLUSH,
+ T_COMMIT_CALLBACK,
+ T_FINISHED
+ } t_state;
+
+ /*
+ * Where in the log does this transaction's commit start? [no locking]
+ */
+ unsigned long t_log_start;
+
+ /*
+ * Number of buffers on the t_buffers list [j_list_lock, no locks
+ * needed for jbd2 thread]
+ */
+ int t_nr_buffers;
+
+ /*
+ * Doubly-linked circular list of all buffers reserved but not yet
+ * modified by this transaction [j_list_lock, no locks needed fo
+ * jbd2 thread]
+ */
+ struct journal_head *t_reserved_list;
+
+ /*
+ * Doubly-linked circular list of all metadata buffers owned by this
+ * transaction [j_list_lock, no locks needed for jbd2 thread]
+ */
+ struct journal_head *t_buffers;
+
+ /*
+ * Doubly-linked circular list of all forget buffers (superseded
+ * buffers which we can un-checkpoint once this transaction commits)
+ * [j_list_lock]
+ */
+ struct journal_head *t_forget;
+
+ /*
+ * Doubly-linked circular list of all buffers still to be flushed before
+ * this transaction can be checkpointed. [j_list_lock]
+ */
+ struct journal_head *t_checkpoint_list;
+
+ /*
+ * Doubly-linked circular list of metadata buffers being
+ * shadowed by log IO. The IO buffers on the iobuf list and
+ * the shadow buffers on this list match each other one for
+ * one at all times. [j_list_lock, no locks needed for jbd2
+ * thread]
+ */
+ struct journal_head *t_shadow_list;
+
+ /*
+ * List of inodes associated with the transaction; e.g., ext4 uses
+ * this to track inodes in data=ordered and data=journal mode that
+ * need special handling on transaction commit; also used by ocfs2.
+ * [j_list_lock]
+ */
+ struct list_head t_inode_list;
+
+ /*
+ * Longest time some handle had to wait for running transaction
+ */
+ unsigned long t_max_wait;
+
+ /*
+ * When transaction started
+ */
+ unsigned long t_start;
+
+ /*
+ * When commit was requested [j_state_lock]
+ */
+ unsigned long t_requested;
+
+ /*
+ * Checkpointing stats [j_list_lock]
+ */
+ struct transaction_chp_stats_s t_chp_stats;
+
+ /*
+ * Number of outstanding updates running on this transaction
+ * [none]
+ */
+ atomic_t t_updates;
+
+ /*
+ * Number of blocks reserved for this transaction in the journal.
+ * This is including all credits reserved when starting transaction
+ * handles as well as all journal descriptor blocks needed for this
+ * transaction. [none]
+ */
+ atomic_t t_outstanding_credits;
+
+ /*
+ * Number of revoke records for this transaction added by already
+ * stopped handles. [none]
+ */
+ atomic_t t_outstanding_revokes;
+
+ /*
+ * How many handles used this transaction? [none]
+ */
+ atomic_t t_handle_count;
+
+ /*
+ * Forward and backward links for the circular list of all transactions
+ * awaiting checkpoint. [j_list_lock]
+ */
+ transaction_t *t_cpnext, *t_cpprev;
+
+ /*
+ * When will the transaction expire (become due for commit), in jiffies?
+ * [no locking]
+ */
+ unsigned long t_expires;
+
+ /*
+ * When this transaction started, in nanoseconds [no locking]
+ */
+ ktime_t t_start_time;
+
+ /*
+ * This transaction is being forced and some process is
+ * waiting for it to finish.
+ */
+ unsigned int t_synchronous_commit:1;
+
+ /* Disk flush needs to be sent to fs partition [no locking] */
+ int t_need_data_flush;
+};
+
+struct transaction_run_stats_s {
+ unsigned long rs_wait;
+ unsigned long rs_request_delay;
+ unsigned long rs_running;
+ unsigned long rs_locked;
+ unsigned long rs_flushing;
+ unsigned long rs_logging;
+
+ __u32 rs_handle_count;
+ __u32 rs_blocks;
+ __u32 rs_blocks_logged;
+};
+
+struct transaction_stats_s {
+ unsigned long ts_tid;
+ unsigned long ts_requested;
+ struct transaction_run_stats_s run;
+};
+
+static inline unsigned long
+jbd2_time_diff(unsigned long start, unsigned long end)
+{
+ if (end >= start)
+ return end - start;
+
+ return end + (MAX_JIFFY_OFFSET - start);
+}
+
+#define JBD2_NR_BATCH 64
+
+enum passtype {PASS_SCAN, PASS_REVOKE, PASS_REPLAY};
+
+#define JBD2_FC_REPLAY_STOP 0
+#define JBD2_FC_REPLAY_CONTINUE 1
+
+/**
+ * struct journal_s - The journal_s type is the concrete type associated with
+ * journal_t.
+ */
+struct journal_s
+{
+ /**
+ * @j_flags: General journaling state flags [j_state_lock,
+ * no lock for quick racy checks]
+ */
+ unsigned long j_flags;
+
+ /**
+ * @j_errno:
+ *
+ * Is there an outstanding uncleared error on the journal (from a prior
+ * abort)? [j_state_lock]
+ */
+ int j_errno;
+
+ /**
+ * @j_abort_mutex: Lock the whole aborting procedure.
+ */
+ struct mutex j_abort_mutex;
+
+ /**
+ * @j_sb_buffer: The first part of the superblock buffer.
+ */
+ struct buffer_head *j_sb_buffer;
+
+ /**
+ * @j_superblock: The second part of the superblock buffer.
+ */
+ journal_superblock_t *j_superblock;
+
+ /**
+ * @j_state_lock: Protect the various scalars in the journal.
+ */
+ rwlock_t j_state_lock;
+
+ /**
+ * @j_barrier_count:
+ *
+ * Number of processes waiting to create a barrier lock [j_state_lock,
+ * no lock for quick racy checks]
+ */
+ int j_barrier_count;
+
+ /**
+ * @j_barrier: The barrier lock itself.
+ */
+ struct mutex j_barrier;
+
+ /**
+ * @j_running_transaction:
+ *
+ * Transactions: The current running transaction...
+ * [j_state_lock, no lock for quick racy checks] [caller holding
+ * open handle]
+ */
+ transaction_t *j_running_transaction;
+
+ /**
+ * @j_committing_transaction:
+ *
+ * the transaction we are pushing to disk
+ * [j_state_lock] [caller holding open handle]
+ */
+ transaction_t *j_committing_transaction;
+
+ /**
+ * @j_checkpoint_transactions:
+ *
+ * ... and a linked circular list of all transactions waiting for
+ * checkpointing. [j_list_lock]
+ */
+ transaction_t *j_checkpoint_transactions;
+
+ /**
+ * @j_wait_transaction_locked:
+ *
+ * Wait queue for waiting for a locked transaction to start committing,
+ * or for a barrier lock to be released.
+ */
+ wait_queue_head_t j_wait_transaction_locked;
+
+ /**
+ * @j_wait_done_commit: Wait queue for waiting for commit to complete.
+ */
+ wait_queue_head_t j_wait_done_commit;
+
+ /**
+ * @j_wait_commit: Wait queue to trigger commit.
+ */
+ wait_queue_head_t j_wait_commit;
+
+ /**
+ * @j_wait_updates: Wait queue to wait for updates to complete.
+ */
+ wait_queue_head_t j_wait_updates;
+
+ /**
+ * @j_wait_reserved:
+ *
+ * Wait queue to wait for reserved buffer credits to drop.
+ */
+ wait_queue_head_t j_wait_reserved;
+
+ /**
+ * @j_fc_wait:
+ *
+ * Wait queue to wait for completion of async fast commits.
+ */
+ wait_queue_head_t j_fc_wait;
+
+ /**
+ * @j_checkpoint_mutex:
+ *
+ * Semaphore for locking against concurrent checkpoints.
+ */
+ struct mutex j_checkpoint_mutex;
+
+ /**
+ * @j_chkpt_bhs:
+ *
+ * List of buffer heads used by the checkpoint routine. This
+ * was moved from jbd2_log_do_checkpoint() to reduce stack
+ * usage. Access to this array is controlled by the
+ * @j_checkpoint_mutex. [j_checkpoint_mutex]
+ */
+ struct buffer_head *j_chkpt_bhs[JBD2_NR_BATCH];
+
+ /**
+ * @j_shrinker:
+ *
+ * Journal head shrinker, reclaim buffer's journal head which
+ * has been written back.
+ */
+ struct shrinker *j_shrinker;
+
+ /**
+ * @j_checkpoint_jh_count:
+ *
+ * Number of journal buffers on the checkpoint list. [j_list_lock]
+ */
+ struct percpu_counter j_checkpoint_jh_count;
+
+ /**
+ * @j_shrink_transaction:
+ *
+ * Record next transaction will shrink on the checkpoint list.
+ * [j_list_lock]
+ */
+ transaction_t *j_shrink_transaction;
+
+ /**
+ * @j_head:
+ *
+ * Journal head: identifies the first unused block in the journal.
+ * [j_state_lock]
+ */
+ unsigned long j_head;
+
+ /**
+ * @j_tail:
+ *
+ * Journal tail: identifies the oldest still-used block in the journal.
+ * [j_state_lock]
+ */
+ unsigned long j_tail;
+
+ /**
+ * @j_free:
+ *
+ * Journal free: how many free blocks are there in the journal?
+ * [j_state_lock]
+ */
+ unsigned long j_free;
+
+ /**
+ * @j_first:
+ *
+ * The block number of the first usable block in the journal
+ * [j_state_lock].
+ */
+ unsigned long j_first;
+
+ /**
+ * @j_last:
+ *
+ * The block number one beyond the last usable block in the journal
+ * [j_state_lock].
+ */
+ unsigned long j_last;
+
+ /**
+ * @j_fc_first:
+ *
+ * The block number of the first fast commit block in the journal
+ * [j_state_lock].
+ */
+ unsigned long j_fc_first;
+
+ /**
+ * @j_fc_off:
+ *
+ * Number of fast commit blocks currently allocated. Accessed only
+ * during fast commit. Currently only process can do fast commit, so
+ * this field is not protected by any lock.
+ */
+ unsigned long j_fc_off;
+
+ /**
+ * @j_fc_last:
+ *
+ * The block number one beyond the last fast commit block in the journal
+ * [j_state_lock].
+ */
+ unsigned long j_fc_last;
+
+ /**
+ * @j_dev: Device where we store the journal.
+ */
+ struct block_device *j_dev;
+
+ /**
+ * @j_blocksize: Block size for the location where we store the journal.
+ */
+ int j_blocksize;
+
+ /**
+ * @j_blk_offset:
+ *
+ * Starting block offset into the device where we store the journal.
+ */
+ unsigned long long j_blk_offset;
+
+ /**
+ * @j_devname: Journal device name.
+ */
+ char j_devname[BDEVNAME_SIZE+24];
+
+ /**
+ * @j_fs_dev:
+ *
+ * Device which holds the client fs. For internal journal this will be
+ * equal to j_dev.
+ */
+ struct block_device *j_fs_dev;
+
+ /**
+ * @j_fs_dev_wb_err:
+ *
+ * Records the errseq of the client fs's backing block device.
+ */
+ errseq_t j_fs_dev_wb_err;
+
+ /**
+ * @j_total_len: Total maximum capacity of the journal region on disk.
+ */
+ unsigned int j_total_len;
+
+ /**
+ * @j_reserved_credits:
+ *
+ * Number of buffers reserved from the running transaction.
+ */
+ atomic_t j_reserved_credits;
+
+ /**
+ * @j_list_lock: Protects the buffer lists and internal buffer state.
+ */
+ spinlock_t j_list_lock;
+
+ /**
+ * @j_inode:
+ *
+ * Optional inode where we store the journal. If present, all
+ * journal block numbers are mapped into this inode via bmap().
+ */
+ struct inode *j_inode;
+
+ /**
+ * @j_tail_sequence:
+ *
+ * Sequence number of the oldest transaction in the log [j_state_lock]
+ */
+ tid_t j_tail_sequence;
+
+ /**
+ * @j_transaction_sequence:
+ *
+ * Sequence number of the next transaction to grant [j_state_lock]
+ */
+ tid_t j_transaction_sequence;
+
+ /**
+ * @j_commit_sequence:
+ *
+ * Sequence number of the most recently committed transaction
+ * [j_state_lock, no lock for quick racy checks]
+ */
+ tid_t j_commit_sequence;
+
+ /**
+ * @j_commit_request:
+ *
+ * Sequence number of the most recent transaction wanting commit
+ * [j_state_lock, no lock for quick racy checks]
+ */
+ tid_t j_commit_request;
+
+ /**
+ * @j_uuid:
+ *
+ * Journal uuid: identifies the object (filesystem, LVM volume etc)
+ * backed by this journal. This will eventually be replaced by an array
+ * of uuids, allowing us to index multiple devices within a single
+ * journal and to perform atomic updates across them.
+ */
+ __u8 j_uuid[16];
+
+ /**
+ * @j_task: Pointer to the current commit thread for this journal.
+ */
+ struct task_struct *j_task;
+
+ /**
+ * @j_max_transaction_buffers:
+ *
+ * Maximum number of metadata buffers to allow in a single compound
+ * commit transaction.
+ */
+ int j_max_transaction_buffers;
+
+ /**
+ * @j_revoke_records_per_block:
+ *
+ * Number of revoke records that fit in one descriptor block.
+ */
+ int j_revoke_records_per_block;
+
+ /**
+ * @j_transaction_overhead_buffers:
+ *
+ * Number of blocks each transaction needs for its own bookkeeping
+ */
+ int j_transaction_overhead_buffers;
+
+ /**
+ * @j_commit_interval:
+ *
+ * What is the maximum transaction lifetime before we begin a commit?
+ */
+ unsigned long j_commit_interval;
+
+ /**
+ * @j_commit_timer: The timer used to wakeup the commit thread.
+ */
+ struct timer_list j_commit_timer;
+
+ /**
+ * @j_revoke_lock: Protect the revoke table.
+ */
+ spinlock_t j_revoke_lock;
+
+ /**
+ * @j_revoke:
+ *
+ * The revoke table - maintains the list of revoked blocks in the
+ * current transaction.
+ */
+ struct jbd2_revoke_table_s *j_revoke;
+
+ /**
+ * @j_revoke_table: Alternate revoke tables for j_revoke.
+ */
+ struct jbd2_revoke_table_s *j_revoke_table[2];
+
+ /**
+ * @j_wbuf: Array of bhs for jbd2_journal_commit_transaction.
+ */
+ struct buffer_head **j_wbuf;
+
+ /**
+ * @j_fc_wbuf: Array of fast commit bhs for fast commit. Accessed only
+ * during a fast commit. Currently only process can do fast commit, so
+ * this field is not protected by any lock.
+ */
+ struct buffer_head **j_fc_wbuf;
+
+ /**
+ * @j_wbufsize:
+ *
+ * Size of @j_wbuf array.
+ */
+ int j_wbufsize;
+
+ /**
+ * @j_fc_wbufsize:
+ *
+ * Size of @j_fc_wbuf array.
+ */
+ int j_fc_wbufsize;
+
+ /**
+ * @j_last_sync_writer:
+ *
+ * The pid of the last person to run a synchronous operation
+ * through the journal.
+ */
+ pid_t j_last_sync_writer;
+
+ /**
+ * @j_average_commit_time:
+ *
+ * The average amount of time in nanoseconds it takes to commit a
+ * transaction to disk. [j_state_lock]
+ */
+ u64 j_average_commit_time;
+
+ /**
+ * @j_min_batch_time:
+ *
+ * Minimum time that we should wait for additional filesystem operations
+ * to get batched into a synchronous handle in microseconds.
+ */
+ u32 j_min_batch_time;
+
+ /**
+ * @j_max_batch_time:
+ *
+ * Maximum time that we should wait for additional filesystem operations
+ * to get batched into a synchronous handle in microseconds.
+ */
+ u32 j_max_batch_time;
+
+ /**
+ * @j_commit_callback:
+ *
+ * This function is called when a transaction is closed.
+ */
+ void (*j_commit_callback)(journal_t *,
+ transaction_t *);
+
+ /**
+ * @j_submit_inode_data_buffers:
+ *
+ * This function is called for all inodes associated with the
+ * committing transaction marked with JI_WRITE_DATA flag
+ * before we start to write out the transaction to the journal.
+ */
+ int (*j_submit_inode_data_buffers)
+ (struct jbd2_inode *);
+
+ /**
+ * @j_finish_inode_data_buffers:
+ *
+ * This function is called for all inodes associated with the
+ * committing transaction marked with JI_WAIT_DATA flag
+ * after we have written the transaction to the journal
+ * but before we write out the commit block.
+ */
+ int (*j_finish_inode_data_buffers)
+ (struct jbd2_inode *);
+
+ /*
+ * Journal statistics
+ */
+
+ /**
+ * @j_history_lock: Protect the transactions statistics history.
+ */
+ spinlock_t j_history_lock;
+
+ /**
+ * @j_proc_entry: procfs entry for the jbd statistics directory.
+ */
+ struct proc_dir_entry *j_proc_entry;
+
+ /**
+ * @j_stats: Overall statistics.
+ */
+ struct transaction_stats_s j_stats;
+
+ /**
+ * @j_failed_commit: Failed journal commit ID.
+ */
+ unsigned int j_failed_commit;
+
+ /**
+ * @j_private:
+ *
+ * An opaque pointer to fs-private information. ext3 puts its
+ * superblock pointer here.
+ */
+ void *j_private;
+
+ /**
+ * @j_csum_seed:
+ *
+ * Precomputed journal UUID checksum for seeding other checksums.
+ */
+ __u32 j_csum_seed;
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+ /**
+ * @j_trans_commit_map:
+ *
+ * Lockdep entity to track transaction commit dependencies. Handles
+ * hold this "lock" for read, when we wait for commit, we acquire the
+ * "lock" for writing. This matches the properties of jbd2 journalling
+ * where the running transaction has to wait for all handles to be
+ * dropped to commit that transaction and also acquiring a handle may
+ * require transaction commit to finish.
+ */
+ struct lockdep_map j_trans_commit_map;
+#endif
+
+ /**
+ * @j_fc_cleanup_callback:
+ *
+ * Clean-up after fast commit or full commit. JBD2 calls this function
+ * after every commit operation.
+ */
+ void (*j_fc_cleanup_callback)(struct journal_s *journal, int full, tid_t tid);
+
+ /**
+ * @j_fc_replay_callback:
+ *
+ * File-system specific function that performs replay of a fast
+ * commit. JBD2 calls this function for each fast commit block found in
+ * the journal. This function should return JBD2_FC_REPLAY_CONTINUE
+ * to indicate that the block was processed correctly and more fast
+ * commit replay should continue. Return value of JBD2_FC_REPLAY_STOP
+ * indicates the end of replay (no more blocks remaining). A negative
+ * return value indicates error.
+ */
+ int (*j_fc_replay_callback)(struct journal_s *journal,
+ struct buffer_head *bh,
+ enum passtype pass, int off,
+ tid_t expected_commit_id);
+
+ /**
+ * @j_bmap:
+ *
+ * Bmap function that should be used instead of the generic
+ * VFS bmap function.
+ */
+ int (*j_bmap)(struct journal_s *journal, sector_t *block);
+};
+
+#define jbd2_might_wait_for_commit(j) \
+ do { \
+ rwsem_acquire(&j->j_trans_commit_map, 0, 0, _THIS_IP_); \
+ rwsem_release(&j->j_trans_commit_map, _THIS_IP_); \
+ } while (0)
+
+/*
+ * We can support any known requested features iff the
+ * superblock is not in version 1. Otherwise we fail to support any
+ * extended sb features.
+ */
+static inline bool jbd2_format_support_feature(journal_t *j)
+{
+ return j->j_superblock->s_header.h_blocktype !=
+ cpu_to_be32(JBD2_SUPERBLOCK_V1);
+}
+
+/* journal feature predicate functions */
+#define JBD2_FEATURE_COMPAT_FUNCS(name, flagname) \
+static inline bool jbd2_has_feature_##name(journal_t *j) \
+{ \
+ return (jbd2_format_support_feature(j) && \
+ ((j)->j_superblock->s_feature_compat & \
+ cpu_to_be32(JBD2_FEATURE_COMPAT_##flagname)) != 0); \
+} \
+static inline void jbd2_set_feature_##name(journal_t *j) \
+{ \
+ (j)->j_superblock->s_feature_compat |= \
+ cpu_to_be32(JBD2_FEATURE_COMPAT_##flagname); \
+} \
+static inline void jbd2_clear_feature_##name(journal_t *j) \
+{ \
+ (j)->j_superblock->s_feature_compat &= \
+ ~cpu_to_be32(JBD2_FEATURE_COMPAT_##flagname); \
+}
+
+#define JBD2_FEATURE_RO_COMPAT_FUNCS(name, flagname) \
+static inline bool jbd2_has_feature_##name(journal_t *j) \
+{ \
+ return (jbd2_format_support_feature(j) && \
+ ((j)->j_superblock->s_feature_ro_compat & \
+ cpu_to_be32(JBD2_FEATURE_RO_COMPAT_##flagname)) != 0); \
+} \
+static inline void jbd2_set_feature_##name(journal_t *j) \
+{ \
+ (j)->j_superblock->s_feature_ro_compat |= \
+ cpu_to_be32(JBD2_FEATURE_RO_COMPAT_##flagname); \
+} \
+static inline void jbd2_clear_feature_##name(journal_t *j) \
+{ \
+ (j)->j_superblock->s_feature_ro_compat &= \
+ ~cpu_to_be32(JBD2_FEATURE_RO_COMPAT_##flagname); \
+}
+
+#define JBD2_FEATURE_INCOMPAT_FUNCS(name, flagname) \
+static inline bool jbd2_has_feature_##name(journal_t *j) \
+{ \
+ return (jbd2_format_support_feature(j) && \
+ ((j)->j_superblock->s_feature_incompat & \
+ cpu_to_be32(JBD2_FEATURE_INCOMPAT_##flagname)) != 0); \
+} \
+static inline void jbd2_set_feature_##name(journal_t *j) \
+{ \
+ (j)->j_superblock->s_feature_incompat |= \
+ cpu_to_be32(JBD2_FEATURE_INCOMPAT_##flagname); \
+} \
+static inline void jbd2_clear_feature_##name(journal_t *j) \
+{ \
+ (j)->j_superblock->s_feature_incompat &= \
+ ~cpu_to_be32(JBD2_FEATURE_INCOMPAT_##flagname); \
+}
+
+JBD2_FEATURE_COMPAT_FUNCS(checksum, CHECKSUM)
+
+JBD2_FEATURE_INCOMPAT_FUNCS(revoke, REVOKE)
+JBD2_FEATURE_INCOMPAT_FUNCS(64bit, 64BIT)
+JBD2_FEATURE_INCOMPAT_FUNCS(async_commit, ASYNC_COMMIT)
+JBD2_FEATURE_INCOMPAT_FUNCS(csum2, CSUM_V2)
+JBD2_FEATURE_INCOMPAT_FUNCS(csum3, CSUM_V3)
+JBD2_FEATURE_INCOMPAT_FUNCS(fast_commit, FAST_COMMIT)
+
+/* Journal high priority write IO operation flags */
+#define JBD2_JOURNAL_REQ_FLAGS (REQ_META | REQ_SYNC | REQ_IDLE)
+
+/*
+ * Journal flag definitions
+ */
+#define JBD2_UNMOUNT 0x001 /* Journal thread is being destroyed */
+#define JBD2_ABORT 0x002 /* Journaling has been aborted for errors. */
+#define JBD2_ACK_ERR 0x004 /* The errno in the sb has been acked */
+#define JBD2_FLUSHED 0x008 /* The journal superblock has been flushed */
+#define JBD2_LOADED 0x010 /* The journal superblock has been loaded */
+#define JBD2_BARRIER 0x020 /* Use IDE barriers */
+#define JBD2_CYCLE_RECORD 0x080 /* Journal cycled record log on
+ * clean and empty filesystem
+ * logging area */
+#define JBD2_FAST_COMMIT_ONGOING 0x100 /* Fast commit is ongoing */
+#define JBD2_FULL_COMMIT_ONGOING 0x200 /* Full commit is ongoing */
+#define JBD2_JOURNAL_FLUSH_DISCARD 0x0001
+#define JBD2_JOURNAL_FLUSH_ZEROOUT 0x0002
+#define JBD2_JOURNAL_FLUSH_VALID (JBD2_JOURNAL_FLUSH_DISCARD | \
+ JBD2_JOURNAL_FLUSH_ZEROOUT)
+
+/*
+ * Function declarations for the journaling transaction and buffer
+ * management
+ */
+
+/* Filing buffers */
+extern bool __jbd2_journal_refile_buffer(struct journal_head *);
+extern void jbd2_journal_refile_buffer(journal_t *, struct journal_head *);
+extern void __jbd2_journal_file_buffer(struct journal_head *, transaction_t *, int);
+extern void jbd2_journal_file_buffer(struct journal_head *, transaction_t *, int);
+static inline void jbd2_file_log_bh(struct list_head *head, struct buffer_head *bh)
+{
+ list_add_tail(&bh->b_assoc_buffers, head);
+}
+static inline void jbd2_unfile_log_bh(struct buffer_head *bh)
+{
+ list_del_init(&bh->b_assoc_buffers);
+}
+
+/* Log buffer allocation */
+struct buffer_head *jbd2_journal_get_descriptor_buffer(transaction_t *, int);
+void jbd2_descriptor_block_csum_set(journal_t *, struct buffer_head *);
+int jbd2_journal_next_log_block(journal_t *, unsigned long long *);
+int jbd2_journal_get_log_tail(journal_t *journal, tid_t *tid,
+ unsigned long *block);
+int __jbd2_update_log_tail(journal_t *journal, tid_t tid, unsigned long block);
+void jbd2_update_log_tail(journal_t *journal, tid_t tid, unsigned long block);
+
+/* Commit management */
+extern void jbd2_journal_commit_transaction(journal_t *);
+
+/* Checkpoint list management */
+enum jbd2_shrink_type {JBD2_SHRINK_DESTROY, JBD2_SHRINK_BUSY_STOP, JBD2_SHRINK_BUSY_SKIP};
+
+void __jbd2_journal_clean_checkpoint_list(journal_t *journal, enum jbd2_shrink_type type);
+unsigned long jbd2_journal_shrink_checkpoint_list(journal_t *journal, unsigned long *nr_to_scan);
+int __jbd2_journal_remove_checkpoint(struct journal_head *);
+int jbd2_journal_try_remove_checkpoint(struct journal_head *jh);
+void jbd2_journal_destroy_checkpoint(journal_t *journal);
+void __jbd2_journal_insert_checkpoint(struct journal_head *, transaction_t *);
+
+
+/*
+ * Triggers
+ */
+
+struct jbd2_buffer_trigger_type {
+ /*
+ * Fired a the moment data to write to the journal are known to be
+ * stable - so either at the moment b_frozen_data is created or just
+ * before a buffer is written to the journal. mapped_data is a mapped
+ * buffer that is the frozen data for commit.
+ */
+ void (*t_frozen)(struct jbd2_buffer_trigger_type *type,
+ struct buffer_head *bh, void *mapped_data,
+ size_t size);
+
+ /*
+ * Fired during journal abort for dirty buffers that will not be
+ * committed.
+ */
+ void (*t_abort)(struct jbd2_buffer_trigger_type *type,
+ struct buffer_head *bh);
+};
+
+extern void jbd2_buffer_frozen_trigger(struct journal_head *jh,
+ void *mapped_data,
+ struct jbd2_buffer_trigger_type *triggers);
+extern void jbd2_buffer_abort_trigger(struct journal_head *jh,
+ struct jbd2_buffer_trigger_type *triggers);
+
+/* Buffer IO */
+extern int jbd2_journal_write_metadata_buffer(transaction_t *transaction,
+ struct journal_head *jh_in,
+ struct buffer_head **bh_out,
+ sector_t blocknr);
+
+/* Transaction cache support */
+extern void jbd2_journal_destroy_transaction_cache(void);
+extern int __init jbd2_journal_init_transaction_cache(void);
+extern void jbd2_journal_free_transaction(transaction_t *);
+
+/*
+ * Journal locking.
+ *
+ * We need to lock the journal during transaction state changes so that nobody
+ * ever tries to take a handle on the running transaction while we are in the
+ * middle of moving it to the commit phase. j_state_lock does this.
+ *
+ * Note that the locking is completely interrupt unsafe. We never touch
+ * journal structures from interrupts.
+ */
+
+static inline handle_t *journal_current_handle(void)
+{
+ return current->journal_info;
+}
+
+/* The journaling code user interface:
+ *
+ * Create and destroy handles
+ * Register buffer modifications against the current transaction.
+ */
+
+extern handle_t *jbd2_journal_start(journal_t *, int nblocks);
+extern handle_t *jbd2__journal_start(journal_t *, int blocks, int rsv_blocks,
+ int revoke_records, gfp_t gfp_mask,
+ unsigned int type, unsigned int line_no);
+extern int jbd2_journal_restart(handle_t *, int nblocks);
+extern int jbd2__journal_restart(handle_t *, int nblocks,
+ int revoke_records, gfp_t gfp_mask);
+extern int jbd2_journal_start_reserved(handle_t *handle,
+ unsigned int type, unsigned int line_no);
+extern void jbd2_journal_free_reserved(handle_t *handle);
+extern int jbd2_journal_extend(handle_t *handle, int nblocks,
+ int revoke_records);
+extern int jbd2_journal_get_write_access(handle_t *, struct buffer_head *);
+extern int jbd2_journal_get_create_access (handle_t *, struct buffer_head *);
+extern int jbd2_journal_get_undo_access(handle_t *, struct buffer_head *);
+void jbd2_journal_set_triggers(struct buffer_head *,
+ struct jbd2_buffer_trigger_type *type);
+extern int jbd2_journal_dirty_metadata (handle_t *, struct buffer_head *);
+extern int jbd2_journal_forget (handle_t *, struct buffer_head *);
+int jbd2_journal_invalidate_folio(journal_t *, struct folio *,
+ size_t offset, size_t length);
+bool jbd2_journal_try_to_free_buffers(journal_t *journal, struct folio *folio);
+extern int jbd2_journal_stop(handle_t *);
+extern int jbd2_journal_flush(journal_t *journal, unsigned int flags);
+extern void jbd2_journal_lock_updates (journal_t *);
+extern void jbd2_journal_unlock_updates (journal_t *);
+
+void jbd2_journal_wait_updates(journal_t *);
+
+extern journal_t * jbd2_journal_init_dev(struct block_device *bdev,
+ struct block_device *fs_dev,
+ unsigned long long start, int len, int bsize);
+extern journal_t * jbd2_journal_init_inode (struct inode *);
+extern int jbd2_journal_update_format (journal_t *);
+extern int jbd2_journal_check_used_features
+ (journal_t *, unsigned long, unsigned long, unsigned long);
+extern int jbd2_journal_check_available_features
+ (journal_t *, unsigned long, unsigned long, unsigned long);
+extern int jbd2_journal_set_features
+ (journal_t *, unsigned long, unsigned long, unsigned long);
+extern void jbd2_journal_clear_features
+ (journal_t *, unsigned long, unsigned long, unsigned long);
+extern int jbd2_journal_load (journal_t *journal);
+extern int jbd2_journal_destroy (journal_t *);
+extern int jbd2_journal_recover (journal_t *journal);
+extern int jbd2_journal_wipe (journal_t *, int);
+extern int jbd2_journal_skip_recovery (journal_t *);
+extern void jbd2_journal_update_sb_errno(journal_t *);
+extern int jbd2_journal_update_sb_log_tail (journal_t *, tid_t,
+ unsigned long, blk_opf_t);
+extern void jbd2_journal_abort (journal_t *, int);
+extern int jbd2_journal_errno (journal_t *);
+extern void jbd2_journal_ack_err (journal_t *);
+extern int jbd2_journal_clear_err (journal_t *);
+extern int jbd2_journal_bmap(journal_t *, unsigned long, unsigned long long *);
+extern int jbd2_journal_force_commit(journal_t *);
+extern int jbd2_journal_force_commit_nested(journal_t *);
+extern int jbd2_journal_inode_ranged_write(handle_t *handle,
+ struct jbd2_inode *inode, loff_t start_byte,
+ loff_t length);
+extern int jbd2_journal_inode_ranged_wait(handle_t *handle,
+ struct jbd2_inode *inode, loff_t start_byte,
+ loff_t length);
+extern int jbd2_journal_finish_inode_data_buffers(
+ struct jbd2_inode *jinode);
+extern int jbd2_journal_begin_ordered_truncate(journal_t *journal,
+ struct jbd2_inode *inode, loff_t new_size);
+extern void jbd2_journal_init_jbd_inode(struct jbd2_inode *jinode, struct inode *inode);
+extern void jbd2_journal_release_jbd_inode(journal_t *journal, struct jbd2_inode *jinode);
+
+/*
+ * journal_head management
+ */
+struct journal_head *jbd2_journal_add_journal_head(struct buffer_head *bh);
+struct journal_head *jbd2_journal_grab_journal_head(struct buffer_head *bh);
+void jbd2_journal_put_journal_head(struct journal_head *jh);
+
+/*
+ * handle management
+ */
+extern struct kmem_cache *jbd2_handle_cache;
+
+/*
+ * This specialized allocator has to be a macro for its allocations to be
+ * accounted separately (to have a separate alloc_tag). The typecast is
+ * intentional to enforce typesafety.
+ */
+#define jbd2_alloc_handle(_gfp_flags) \
+ ((handle_t *)kmem_cache_zalloc(jbd2_handle_cache, _gfp_flags))
+
+static inline void jbd2_free_handle(handle_t *handle)
+{
+ kmem_cache_free(jbd2_handle_cache, handle);
+}
+
+/*
+ * jbd2_inode management (optional, for those file systems that want to use
+ * dynamically allocated jbd2_inode structures)
+ */
+extern struct kmem_cache *jbd2_inode_cache;
+
+/*
+ * This specialized allocator has to be a macro for its allocations to be
+ * accounted separately (to have a separate alloc_tag). The typecast is
+ * intentional to enforce typesafety.
+ */
+#define jbd2_alloc_inode(_gfp_flags) \
+ ((struct jbd2_inode *)kmem_cache_alloc(jbd2_inode_cache, _gfp_flags))
+
+static inline void jbd2_free_inode(struct jbd2_inode *jinode)
+{
+ kmem_cache_free(jbd2_inode_cache, jinode);
+}
+
+/* Primary revoke support */
+#define JOURNAL_REVOKE_DEFAULT_HASH 256
+extern int jbd2_journal_init_revoke(journal_t *, int);
+extern void jbd2_journal_destroy_revoke_record_cache(void);
+extern void jbd2_journal_destroy_revoke_table_cache(void);
+extern int __init jbd2_journal_init_revoke_record_cache(void);
+extern int __init jbd2_journal_init_revoke_table_cache(void);
+struct jbd2_revoke_table_s *jbd2_journal_init_revoke_table(int hash_size);
+void jbd2_journal_destroy_revoke_table(struct jbd2_revoke_table_s *table);
+
+extern void jbd2_journal_destroy_revoke(journal_t *);
+extern int jbd2_journal_revoke (handle_t *, unsigned long long, struct buffer_head *);
+extern void jbd2_journal_cancel_revoke(handle_t *, struct journal_head *);
+extern void jbd2_journal_write_revoke_records(transaction_t *transaction,
+ struct list_head *log_bufs);
+
+/* Recovery revoke support */
+extern int jbd2_journal_set_revoke(journal_t *, unsigned long long, tid_t);
+extern int jbd2_journal_test_revoke(journal_t *, unsigned long long, tid_t);
+extern void jbd2_journal_clear_revoke(journal_t *);
+extern void jbd2_journal_switch_revoke_table(journal_t *journal);
+extern void jbd2_clear_buffer_revoked_flags(journal_t *journal);
+
+/*
+ * The log thread user interface:
+ *
+ * Request space in the current transaction, and force transaction commit
+ * transitions on demand.
+ */
+
+int jbd2_log_start_commit(journal_t *journal, tid_t tid);
+int jbd2_journal_start_commit(journal_t *journal, tid_t *tid);
+int jbd2_log_wait_commit(journal_t *journal, tid_t tid);
+int jbd2_transaction_committed(journal_t *journal, tid_t tid);
+int jbd2_complete_transaction(journal_t *journal, tid_t tid);
+int jbd2_log_do_checkpoint(journal_t *journal);
+int jbd2_trans_will_send_data_barrier(journal_t *journal, tid_t tid);
+
+void __jbd2_log_wait_for_space(journal_t *journal);
+extern void __jbd2_journal_drop_transaction(journal_t *, transaction_t *);
+extern int jbd2_cleanup_journal_tail(journal_t *);
+
+/* Fast commit related APIs */
+int jbd2_fc_begin_commit(journal_t *journal, tid_t tid);
+int jbd2_fc_end_commit(journal_t *journal);
+int jbd2_fc_end_commit_fallback(journal_t *journal);
+int jbd2_fc_get_buf(journal_t *journal, struct buffer_head **bh_out);
+int jbd2_submit_inode_data(journal_t *journal, struct jbd2_inode *jinode);
+int jbd2_wait_inode_data(journal_t *journal, struct jbd2_inode *jinode);
+int jbd2_fc_wait_bufs(journal_t *journal, int num_blks);
+void jbd2_fc_release_bufs(journal_t *journal);
+
+/*
+ * is_journal_abort
+ *
+ * Simple test wrapper function to test the JBD2_ABORT state flag. This
+ * bit, when set, indicates that we have had a fatal error somewhere,
+ * either inside the journaling layer or indicated to us by the client
+ * (eg. ext3), and that we and should not commit any further
+ * transactions.
+ */
+
+static inline int is_journal_aborted(journal_t *journal)
+{
+ return journal->j_flags & JBD2_ABORT;
+}
+
+static inline int is_handle_aborted(handle_t *handle)
+{
+ if (handle->h_aborted || !handle->h_transaction)
+ return 1;
+ return is_journal_aborted(handle->h_transaction->t_journal);
+}
+
+static inline void jbd2_journal_abort_handle(handle_t *handle)
+{
+ handle->h_aborted = 1;
+}
+
+static inline void jbd2_init_fs_dev_write_error(journal_t *journal)
+{
+ struct address_space *mapping = journal->j_fs_dev->bd_mapping;
+
+ /*
+ * Save the original wb_err value of client fs's bdev mapping which
+ * could be used to detect the client fs's metadata async write error.
+ */
+ errseq_check_and_advance(&mapping->wb_err, &journal->j_fs_dev_wb_err);
+}
+
+static inline int jbd2_check_fs_dev_write_error(journal_t *journal)
+{
+ struct address_space *mapping = journal->j_fs_dev->bd_mapping;
+
+ return errseq_check(&mapping->wb_err,
+ READ_ONCE(journal->j_fs_dev_wb_err));
+}
+
+#endif /* __KERNEL__ */
+
+/* Comparison functions for transaction IDs: perform comparisons using
+ * modulo arithmetic so that they work over sequence number wraps. */
+
+static inline int tid_gt(tid_t x, tid_t y)
+{
+ int difference = (x - y);
+ return (difference > 0);
+}
+
+static inline int tid_geq(tid_t x, tid_t y)
+{
+ int difference = (x - y);
+ return (difference >= 0);
+}
+
+extern int jbd2_journal_blocks_per_folio(struct inode *inode);
+extern size_t journal_tag_bytes(journal_t *journal);
+
+static inline int jbd2_journal_has_csum_v2or3(journal_t *journal)
+{
+ return jbd2_has_feature_csum2(journal) ||
+ jbd2_has_feature_csum3(journal);
+}
+
+static inline int jbd2_journal_get_num_fc_blks(journal_superblock_t *jsb)
+{
+ int num_fc_blocks = be32_to_cpu(jsb->s_num_fc_blks);
+
+ return num_fc_blocks ? num_fc_blocks : JBD2_DEFAULT_FAST_COMMIT_BLOCKS;
+}
+
+/*
+ * Return number of free blocks in the log. Must be called under j_state_lock.
+ */
+static inline unsigned long jbd2_log_space_left(journal_t *journal)
+{
+ /* Allow for rounding errors */
+ long free = journal->j_free - 32;
+
+ if (journal->j_committing_transaction) {
+ free -= atomic_read(&journal->
+ j_committing_transaction->t_outstanding_credits);
+ }
+ return max_t(long, free, 0);
+}
+
+/*
+ * Definitions which augment the buffer_head layer
+ */
+
+/* journaling buffer types */
+#define BJ_None 0 /* Not journaled */
+#define BJ_Metadata 1 /* Normal journaled metadata */
+#define BJ_Forget 2 /* Buffer superseded by this transaction */
+#define BJ_Shadow 3 /* Buffer contents being shadowed to the log */
+#define BJ_Reserved 4 /* Buffer is reserved for access by journal */
+#define BJ_Types 5
+
+static inline u32 jbd2_chksum(u32 crc, const void *address, unsigned int length)
+{
+ return crc32c(crc, address, length);
+}
+
+/* Return most recent uncommitted transaction */
+static inline tid_t jbd2_get_latest_transaction(journal_t *journal)
+{
+ tid_t tid;
+
+ read_lock(&journal->j_state_lock);
+ tid = journal->j_commit_request;
+ if (journal->j_running_transaction)
+ tid = journal->j_running_transaction->t_tid;
+ read_unlock(&journal->j_state_lock);
+ return tid;
+}
+
+static inline int jbd2_handle_buffer_credits(handle_t *handle)
+{
+ journal_t *journal;
+
+ if (!handle->h_reserved)
+ journal = handle->h_transaction->t_journal;
+ else
+ journal = handle->h_journal;
+
+ return handle->h_total_credits -
+ DIV_ROUND_UP(handle->h_revoke_credits_requested,
+ journal->j_revoke_records_per_block);
+}
+
+#ifdef __KERNEL__
+
+#define buffer_trace_init(bh) do {} while (0)
+#define print_buffer_fields(bh) do {} while (0)
+#define print_buffer_trace(bh) do {} while (0)
+#define BUFFER_TRACE(bh, info) do {} while (0)
+#define BUFFER_TRACE2(bh, bh2, info) do {} while (0)
+#define JBUFFER_TRACE(jh, info) do {} while (0)
+
+#endif /* __KERNEL__ */
+
+#define EFSBADCRC EBADMSG /* Bad CRC detected */
+#define EFSCORRUPTED EUCLEAN /* Filesystem is corrupted */
+
+#endif /* _LINUX_JBD2_H */