From: Zhang Yi <yi.zhang@huawei.com>
To: <linux-ext4@vger.kernel.org>, <linux-fsdevel@vger.kernel.org>,
<jack@suse.cz>, <tytso@mit.edu>
Cc: <adilger.kernel@dilger.ca>, <david@fromorbit.com>,
<hch@infradead.org>, <yi.zhang@huawei.com>
Subject: [RFC PATCH v4 2/8] jbd2: ensure abort the journal if detect IO error when writing original buffer back
Date: Thu, 10 Jun 2021 19:24:34 +0800 [thread overview]
Message-ID: <20210610112440.3438139-3-yi.zhang@huawei.com> (raw)
In-Reply-To: <20210610112440.3438139-1-yi.zhang@huawei.com>
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>
---
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 bf5511d19ac5..d27c10f4502f 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 2dc944442802..90146755941f 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",
@@ -1995,6 +1999,16 @@ 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 db0e1920cb12..f9b5e657b8f3 100644
--- a/include/linux/jbd2.h
+++ b/include/linux/jbd2.h
@@ -779,6 +779,11 @@ struct journal_s
*/
unsigned long j_flags;
+ /**
+ * @j_atomic_flags: Atomic journaling state flags.
+ */
+ unsigned long j_atomic_flags;
+
/**
* @j_errno:
*
@@ -1371,6 +1376,12 @@ 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
--
2.31.1
next prev parent reply other threads:[~2021-06-10 11:15 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-10 11:24 [RFC PATCH v4 0/8] ext4, jbd2: fix 3 issues about bdev_try_to_free_page() Zhang Yi
2021-06-10 11:24 ` [RFC PATCH v4 1/8] jbd2: remove the out label in __jbd2_journal_remove_checkpoint() Zhang Yi
2021-06-24 14:35 ` Theodore Ts'o
2021-06-10 11:24 ` Zhang Yi [this message]
2021-06-24 14:35 ` [RFC PATCH v4 2/8] jbd2: ensure abort the journal if detect IO error when writing original buffer back Theodore Ts'o
2021-06-10 11:24 ` [RFC PATCH v4 3/8] jbd2: don't abort the journal when freeing buffers Zhang Yi
2021-06-24 14:35 ` Theodore Ts'o
2021-06-10 11:24 ` [RFC PATCH v4 4/8] jbd2: remove redundant buffer io error checks Zhang Yi
2021-06-24 14:35 ` Theodore Ts'o
2021-06-10 11:24 ` [RFC PATCH v4 5/8] jbd2,ext4: add a shrinker to release checkpointed buffers Zhang Yi
2021-06-10 16:12 ` Jan Kara
2021-06-24 14:56 ` Theodore Ts'o
2021-06-10 11:24 ` [RFC PATCH v4 6/8] jbd2: simplify journal_clean_one_cp_list() Zhang Yi
2021-06-24 14:56 ` Theodore Ts'o
2021-06-10 11:24 ` [RFC PATCH v4 7/8] ext4: remove bdev_try_to_free_page() callback Zhang Yi
2021-06-24 14:56 ` Theodore Ts'o
2021-06-10 11:24 ` [RFC PATCH v4 8/8] fs: remove bdev_try_to_free_page callback Zhang Yi
2021-06-24 14:56 ` Theodore Ts'o
2021-06-17 9:48 ` [RFC PATCH v4 0/8] ext4, jbd2: fix 3 issues about bdev_try_to_free_page() Christoph Hellwig
2021-06-21 15:25 ` Christoph Hellwig
2021-06-22 8:24 ` Jan Kara
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