From: Zhang Yi
mainline inclusion
from mainline-v5.14-rc1
commit fcf37549ae19e904bc6a5eadf5c25eca36100c5e
category: bugfix
issue: #I3ZXZF
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
---------------------------
Although we merged c044f3d8360 ("jbd2: abort journal if free a async
write error metadata buffer"), there is a race between
jbd2_journal_try_to_free_buffers() and jbd2_journal_destroy(), so the
jbd2_log_do_checkpoint() may still fail to detect the buffer write
io error flag which may lead to filesystem inconsistency.
jbd2_journal_try_to_free_buffers() ext4_put_super()
jbd2_journal_destroy()
__jbd2_journal_remove_checkpoint()
detect buffer write error jbd2_log_do_checkpoint()
jbd2_cleanup_journal_tail()
<--- lead to inconsistency
jbd2_journal_abort()
Fix this issue by introducing a new atomic flag which only have one
JBD2_CHECKPOINT_IO_ERROR bit now, and set it in
__jbd2_journal_remove_checkpoint() when freeing a checkpoint buffer
which has write_io_error flag. Then jbd2_journal_destroy() will detect
this mark and abort the journal to prevent updating log tail.
Signed-off-by: Zhang Yi
Reviewed-by: Jan Kara
Link: https://lore.kernel.org/r/20210610112440.3438139-3-yi.zhang@huawei.com
Signed-off-by: Theodore Ts'o
Reviewed-by: Yang Erkun
Signed-off-by: Chen Jun
Signed-off-by: Yu Changchun
---
fs/jbd2/checkpoint.c | 12 ++++++++++++
fs/jbd2/journal.c | 14 ++++++++++++++
include/linux/jbd2.h | 11 +++++++++++
3 files changed, 37 insertions(+)
diff --git a/fs/jbd2/checkpoint.c b/fs/jbd2/checkpoint.c
index 96a5713b466a..172a5ad64071 100644
--- a/fs/jbd2/checkpoint.c
+++ b/fs/jbd2/checkpoint.c
@@ -564,6 +564,7 @@ int __jbd2_journal_remove_checkpoint(struct journal_head *jh)
struct transaction_chp_stats_s *stats;
transaction_t *transaction;
journal_t *journal;
+ struct buffer_head *bh = jh2bh(jh);
JBUFFER_TRACE(jh, "entry");
@@ -575,6 +576,17 @@ int __jbd2_journal_remove_checkpoint(struct journal_head *jh)
journal = transaction->t_journal;
JBUFFER_TRACE(jh, "removing from transaction");
+
+ /*
+ * If we have failed to write the buffer out to disk, the filesystem
+ * may become inconsistent. We cannot abort the journal here since
+ * we hold j_list_lock and we have to be careful about races with
+ * jbd2_journal_destroy(). So mark the writeback IO error in the
+ * journal here and we abort the journal later from a better context.
+ */
+ if (buffer_write_io_error(bh))
+ set_bit(JBD2_CHECKPOINT_IO_ERROR, &journal->j_atomic_flags);
+
__buffer_unlink(jh);
jh->b_cp_transaction = NULL;
jbd2_journal_put_journal_head(jh);
diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index 188f79d76988..1a11b06b9de9 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -1618,6 +1618,10 @@ int jbd2_journal_update_sb_log_tail(journal_t *journal, tid_t tail_tid,
if (is_journal_aborted(journal))
return -EIO;
+ if (test_bit(JBD2_CHECKPOINT_IO_ERROR, &journal->j_atomic_flags)) {
+ jbd2_journal_abort(journal, -EIO);
+ return -EIO;
+ }
BUG_ON(!mutex_is_locked(&journal->j_checkpoint_mutex));
jbd_debug(1, "JBD2: updating superblock (start %lu, seq %u)\n",
@@ -1997,6 +2001,16 @@ int jbd2_journal_destroy(journal_t *journal)
J_ASSERT(journal->j_checkpoint_transactions == NULL);
spin_unlock(&journal->j_list_lock);
+ /*
+ * OK, all checkpoint transactions have been checked, now check the
+ * write out io error flag and abort the journal if some buffer failed
+ * to write back to the original location, otherwise the filesystem
+ * may become inconsistent.
+ */
+ if (!is_journal_aborted(journal) &&
+ test_bit(JBD2_CHECKPOINT_IO_ERROR, &journal->j_atomic_flags))
+ jbd2_journal_abort(journal, -EIO);
+
if (journal->j_sb_buffer) {
if (!is_journal_aborted(journal)) {
mutex_lock_io(&journal->j_checkpoint_mutex);
diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h
index 578ff196b3ce..b737024b4b9c 100644
--- a/include/linux/jbd2.h
+++ b/include/linux/jbd2.h
@@ -771,6 +771,11 @@ struct journal_s
*/
unsigned long j_flags;
+ /**
+ * @j_atomic_flags: Atomic journaling state flags.
+ */
+ unsigned long j_atomic_flags;
+
/**
* @j_errno:
*
@@ -1361,6 +1366,12 @@ JBD2_FEATURE_INCOMPAT_FUNCS(fast_commit, FAST_COMMIT)
#define JBD2_FAST_COMMIT_ONGOING 0x100 /* Fast commit is ongoing */
#define JBD2_FULL_COMMIT_ONGOING 0x200 /* Full commit is ongoing */
+/*
+ * Journal atomic flag definitions
+ */
+#define JBD2_CHECKPOINT_IO_ERROR 0x001 /* Detect io error while writing
+ * buffer back to disk */
+
/*
* Function declarations for the journaling transaction and buffer
* management
--
2.22.0
