| Message ID | 20241203014407.805916-3-yi.zhang@huaweicloud.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | jbd2: two straightforward fixes | expand |
on 12/3/2024 9:44 AM, Zhang Yi wrote: > From: Zhang Yi <yi.zhang@huawei.com> > > When committing transaction in jbd2_journal_commit_transaction(), the > disk caches for the filesystem device should be flushed before updating > the journal tail sequence. However, this step is missed if the journal > is not located on the filesystem device. As a result, the filesystem may > become inconsistent following a power failure or system crash. Fix it by > ensuring that the filesystem device is flushed appropriately. > > Fixes: 3339578f0578 ("jbd2: cleanup journal tail after transaction commit") > Signed-off-by: Zhang Yi <yi.zhang@huawei.com> > --- > fs/jbd2/commit.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c > index 4305a1ac808a..f95cf272a1b5 100644 > --- a/fs/jbd2/commit.c > +++ b/fs/jbd2/commit.c > @@ -776,9 +776,9 @@ void jbd2_journal_commit_transaction(journal_t *journal) > /* > * If the journal is not located on the file system device, > * then we must flush the file system device before we issue > - * the commit record > + * the commit record and update the journal tail sequence. > */ > - if (commit_transaction->t_need_data_flush && > + if ((commit_transaction->t_need_data_flush || update_tail) && > (journal->j_fs_dev != journal->j_dev) && > (journal->j_flags & JBD2_BARRIER)) > blkdev_issue_flush(journal->j_fs_dev); > In journal_submit_commit_record(), we will submit commit block with REQ_PREFLUSH which is supposed to ensure disk cache is flushed before writing commit block. So I think the current code is fine. Please correct me if I miss anything. Thanks, Kemeng
On 2024/12/3 14:53, Kemeng Shi wrote: > > > on 12/3/2024 9:44 AM, Zhang Yi wrote: >> From: Zhang Yi <yi.zhang@huawei.com> >> >> When committing transaction in jbd2_journal_commit_transaction(), the >> disk caches for the filesystem device should be flushed before updating >> the journal tail sequence. However, this step is missed if the journal >> is not located on the filesystem device. As a result, the filesystem may >> become inconsistent following a power failure or system crash. Fix it by >> ensuring that the filesystem device is flushed appropriately. >> >> Fixes: 3339578f0578 ("jbd2: cleanup journal tail after transaction commit") >> Signed-off-by: Zhang Yi <yi.zhang@huawei.com> >> --- >> fs/jbd2/commit.c | 4 ++-- >> 1 file changed, 2 insertions(+), 2 deletions(-) >> >> diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c >> index 4305a1ac808a..f95cf272a1b5 100644 >> --- a/fs/jbd2/commit.c >> +++ b/fs/jbd2/commit.c >> @@ -776,9 +776,9 @@ void jbd2_journal_commit_transaction(journal_t *journal) >> /* >> * If the journal is not located on the file system device, >> * then we must flush the file system device before we issue >> - * the commit record >> + * the commit record and update the journal tail sequence. >> */ >> - if (commit_transaction->t_need_data_flush && >> + if ((commit_transaction->t_need_data_flush || update_tail) && >> (journal->j_fs_dev != journal->j_dev) && >> (journal->j_flags & JBD2_BARRIER)) >> blkdev_issue_flush(journal->j_fs_dev); >> > In journal_submit_commit_record(), we will submit commit block with REQ_PREFLUSH > which is supposed to ensure disk cache is flushed before writing commit block. > So I think the current code is fine. > Please correct me if I miss anything. > The commit I/O with REQ_PREFLUSH only flushes 'journal->j_dev', not 'journal->j_fs_dev'. We need to flush journal->j_fs_dev to ensure that all written metadata has been persisted to the filesystem disk, Until then, we cannot update the tail sequence. Thanks, Yi.
On Tue 03-12-24 09:44:07, Zhang Yi wrote: > From: Zhang Yi <yi.zhang@huawei.com> > > When committing transaction in jbd2_journal_commit_transaction(), the > disk caches for the filesystem device should be flushed before updating > the journal tail sequence. However, this step is missed if the journal > is not located on the filesystem device. As a result, the filesystem may > become inconsistent following a power failure or system crash. Fix it by > ensuring that the filesystem device is flushed appropriately. > > Fixes: 3339578f0578 ("jbd2: cleanup journal tail after transaction commit") > Signed-off-by: Zhang Yi <yi.zhang@huawei.com> Ah, good catch. Feel free to add: Reviewed-by: Jan Kara <jack@suse.cz> Honza > --- > fs/jbd2/commit.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c > index 4305a1ac808a..f95cf272a1b5 100644 > --- a/fs/jbd2/commit.c > +++ b/fs/jbd2/commit.c > @@ -776,9 +776,9 @@ void jbd2_journal_commit_transaction(journal_t *journal) > /* > * If the journal is not located on the file system device, > * then we must flush the file system device before we issue > - * the commit record > + * the commit record and update the journal tail sequence. > */ > - if (commit_transaction->t_need_data_flush && > + if ((commit_transaction->t_need_data_flush || update_tail) && > (journal->j_fs_dev != journal->j_dev) && > (journal->j_flags & JBD2_BARRIER)) > blkdev_issue_flush(journal->j_fs_dev); > -- > 2.46.1 >
diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c index 4305a1ac808a..f95cf272a1b5 100644 --- a/fs/jbd2/commit.c +++ b/fs/jbd2/commit.c @@ -776,9 +776,9 @@ void jbd2_journal_commit_transaction(journal_t *journal) /* * If the journal is not located on the file system device, * then we must flush the file system device before we issue - * the commit record + * the commit record and update the journal tail sequence. */ - if (commit_transaction->t_need_data_flush && + if ((commit_transaction->t_need_data_flush || update_tail) && (journal->j_fs_dev != journal->j_dev) && (journal->j_flags & JBD2_BARRIER)) blkdev_issue_flush(journal->j_fs_dev);