jbd2: ensure abort the journal if detect IO error when writing original buffer back
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 <yi.zhang@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20210610112440.3438139-3-yi.zhang@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
diff --git a/fs/jbd2/checkpoint.c b/fs/jbd2/checkpoint.c
index bf5511d..d27c10f 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 f88895b..8b3f5bb 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -1610,6 +1610,10 @@ 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",
@@ -2091,6 +2095,16 @@ 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 8543233..d5db408 100644
--- a/include/linux/jbd2.h
+++ b/include/linux/jbd2.h
@@ -780,6 +780,11 @@ struct journal_s
unsigned long j_flags;
/**
+ * @j_atomic_flags: Atomic journaling state flags.
+ */
+ unsigned long j_atomic_flags;
+
+ /**
* @j_errno:
*
* Is there an outstanding uncleared error on the journal (from a prior
@@ -1376,6 +1381,12 @@ JBD2_FEATURE_INCOMPAT_FUNCS(fast_commit, FAST_COMMIT)
JBD2_JOURNAL_FLUSH_ZEROOUT)
/*
+ * 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
*/
