There are several rules we must follows during data integrity
1) barrier MUST being sent if barrier_opt is enabled (and must not otherwise)
2) If we can guarantee that barrier will be sent for us,
we can skip explicit barrier.
Change log:
- Fix needs_barrier var initialization according to rule (1)
- Avoid barriers if barrier_opt was not enabled for non-journal mode
according to rule (1)
- Style cleanup flush optimization according to rule (2)
CC: linux-e...@vger.kernel.org
Signed-off-by: Dmitry Monakhov <dmonak...@openvz.org>
---
fs/ext4/fsync.c | 13 +++++++------
1 files changed, 7 insertions(+), 6 deletions(-)
diff --git a/fs/ext4/fsync.c b/fs/ext4/fsync.c
index a8bc47f..2b0fd69 100644
--- a/fs/ext4/fsync.c
+++ b/fs/ext4/fsync.c
@@ -92,7 +92,7 @@ int ext4_sync_file(struct file *file, loff_t start, loff_t
end, int datasync)
journal_t *journal = EXT4_SB(inode->i_sb)->s_journal;
int ret = 0, err;
tid_t commit_tid;
- bool needs_barrier = false;
+ bool needs_barrier = test_opt(inode->i_sb, BARRIER);
J_ASSERT(ext4_journal_current_handle() == NULL);
@@ -107,10 +107,10 @@ int ext4_sync_file(struct file *file, loff_t start,
loff_t end, int datasync)
}
if (!journal) {
- ret = generic_file_fsync(file, start, end, datasync);
+ ret = __generic_file_fsync(file, start, end, datasync);
if (!ret && !hlist_empty(&inode->i_dentry))
ret = ext4_sync_parent(inode);
- goto out;
+ goto out_flush;
}
ret = filemap_write_and_wait_range(inode->i_mapping, start, end);
@@ -136,10 +136,11 @@ int ext4_sync_file(struct file *file, loff_t start,
loff_t end, int datasync)
}
commit_tid = datasync ? ei->i_datasync_tid : ei->i_sync_tid;
- if (journal->j_flags & JBD2_BARRIER &&
- !jbd2_trans_will_send_data_barrier(journal, commit_tid))
- needs_barrier = true;
+ if (needs_barrier &&
+ jbd2_trans_will_send_data_barrier(journal, commit_tid))
+ needs_barrier = false;
ret = jbd2_complete_transaction(journal, commit_tid);
+out_flush:
if (needs_barrier) {
err = blkdev_issue_flush(inode->i_sb->s_bdev, GFP_KERNEL, NULL);
if (!ret)
--
1.7.1
--
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