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| author | Theodore Ts'o <tytso@mit.edu> | 2013-04-03 22:02:52 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-03-11 16:10:05 -0700 |
| commit | ebdc12a0b5ed501c23b52b1ab5d28aea681badcd (patch) | |
| tree | 2b30194a0d3fcca2271a117a24af8f5bd1a884ac /fs/ext4 | |
| parent | d7d659d6baad472a8e810412e0c27cafe899bde9 (diff) | |
ext4/jbd2: don't wait (forever) for stale tid caused by wraparound
commit d76a3a77113db020d9bb1e894822869410450bd9 upstream.
In the case where an inode has a very stale transaction id (tid) in
i_datasync_tid or i_sync_tid, it's possible that after a very large
(2**31) number of transactions, that the tid number space might wrap,
causing tid_geq()'s calculations to fail.
Commit deeeaf13 "jbd2: fix fsync() tid wraparound bug", later modified
by commit e7b04ac0 "jbd2: don't wake kjournald unnecessarily",
attempted to fix this problem, but it only avoided kjournald spinning
forever by fixing the logic in jbd2_log_start_commit().
Unfortunately, in the codepaths in fs/ext4/fsync.c and fs/ext4/inode.c
that might call jbd2_log_start_commit() with a stale tid, those
functions will subsequently call jbd2_log_wait_commit() with the same
stale tid, and then wait for a very long time. To fix this, we
replace the calls to jbd2_log_start_commit() and
jbd2_log_wait_commit() with a call to a new function,
jbd2_complete_transaction(), which will correctly handle stale tid's.
As a bonus, jbd2_complete_transaction() will avoid locking
j_state_lock for writing unless a commit needs to be started. This
should have a small (but probably not measurable) improvement for
ext4's scalability.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Reported-by: Ben Hutchings <ben@decadent.org.uk>
Reported-by: George Barnett <gbarnett@atlassian.com>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Cc: Rui Xiang <rui.xiang@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs/ext4')
| -rw-r--r-- | fs/ext4/fsync.c | 3 | ||||
| -rw-r--r-- | fs/ext4/inode.c | 3 |
2 files changed, 2 insertions, 4 deletions
diff --git a/fs/ext4/fsync.c b/fs/ext4/fsync.c index bb6c7d81131..a8d03a4d3f8 100644 --- a/fs/ext4/fsync.c +++ b/fs/ext4/fsync.c @@ -260,8 +260,7 @@ int ext4_sync_file(struct file *file, loff_t start, loff_t end, int datasync) if (journal->j_flags & JBD2_BARRIER && !jbd2_trans_will_send_data_barrier(journal, commit_tid)) needs_barrier = true; - jbd2_log_start_commit(journal, commit_tid); - ret = jbd2_log_wait_commit(journal, commit_tid); + ret = jbd2_complete_transaction(journal, commit_tid); if (needs_barrier) blkdev_issue_flush(inode->i_sb->s_bdev, GFP_KERNEL, NULL); out: diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 98bff01eed6..755345a30f4 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -149,8 +149,7 @@ void ext4_evict_inode(struct inode *inode) journal_t *journal = EXT4_SB(inode->i_sb)->s_journal; tid_t commit_tid = EXT4_I(inode)->i_datasync_tid; - jbd2_log_start_commit(journal, commit_tid); - jbd2_log_wait_commit(journal, commit_tid); + jbd2_complete_transaction(journal, commit_tid); filemap_write_and_wait(&inode->i_data); } truncate_inode_pages(&inode->i_data, 0); |