[Concept,09/14] linux: jbd2: Add jbd2_journal_exit_global for clean shutdown
Commit Message
From: Simon Glass <simon.glass@canonical.com>
In U-Boot, filesystems may be mounted and unmounted multiple times in a
single session. The JBD2 global state (caches) was only initialized once
and never cleaned up, preventing proper reinitialization.
Add jbd2_journal_exit_global() to properly destroy caches and reset the
initialization flag. This allows the JBD2 subsystem to be cleanly
reinitialized on subsequent mounts.
Co-developed-by: Claude Opus 4.5 <noreply@anthropic.com>
Signed-off-by: Simon Glass <simon.glass@canonical.com>
---
fs/jbd2/journal.c | 33 +++++++++++++++++++++++++++++++++
include/linux/jbd2.h | 1 +
2 files changed, 34 insertions(+)
@@ -3140,6 +3140,10 @@ static int __init journal_init(void)
return ret;
}
+#ifdef __UBOOT__
+static bool jbd2_initialized;
+#endif
+
/**
* jbd2_journal_init_global() - Initialize JBD2 global state
*
@@ -3150,18 +3154,47 @@ static int __init journal_init(void)
*/
int jbd2_journal_init_global(void)
{
+#ifdef __UBOOT__
+ if (jbd2_initialized)
+ return 0;
+#else
static bool initialized;
if (initialized)
return 0;
+#endif
if (journal_init())
return -ENOMEM;
+#ifdef __UBOOT__
+ jbd2_initialized = true;
+#else
initialized = true;
+#endif
return 0;
}
+#ifdef __UBOOT__
+/**
+ * jbd2_journal_exit_global() - Clean up JBD2 global state
+ *
+ * This should be called when unmounting the last ext4 filesystem to
+ * properly clean up all JBD2 caches and reset global state. This is
+ * important in U-Boot where we may mount/unmount filesystems multiple
+ * times in a single session.
+ */
+void jbd2_journal_exit_global(void)
+{
+ if (!jbd2_initialized)
+ return;
+
+ jbd2_remove_jbd_stats_proc_entry();
+ jbd2_journal_destroy_caches();
+ jbd2_initialized = false;
+}
+#endif
+
static void __exit journal_exit(void)
{
#ifdef CONFIG_JBD2_DEBUG
@@ -75,6 +75,7 @@ void __jbd2_debug(int level, const char *file, const char *func,
extern void *jbd2_alloc(size_t size, gfp_t flags);
extern void jbd2_free(void *ptr, size_t size);
extern int jbd2_journal_init_global(void);
+extern void jbd2_journal_exit_global(void);
#define JBD2_MIN_JOURNAL_BLOCKS 1024
#define JBD2_DEFAULT_FAST_COMMIT_BLOCKS 256