xfs: reduce ilock acquisitions in xfs_file_fsync

If the inode is not pinned by the time fsync is called we don't need the
ilock to protect against concurrent clearing of ili_fsync_fields as the
inode won't need a log flush or clearing of these fields.  Not taking
the iolock allows for full concurrency of fsync and thus O_DSYNC
completions with io_uring/aio write submissions.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
This commit is contained in:
Christoph Hellwig 2021-01-22 16:48:25 -08:00 committed by Darrick J. Wong
parent f22c7f8777
commit ae29e4220f

View file

@ -200,7 +200,14 @@ xfs_file_fsync(
else if (mp->m_logdev_targp != mp->m_ddev_targp)
xfs_blkdev_issue_flush(mp->m_ddev_targp);
error = xfs_fsync_flush_log(ip, datasync, &log_flushed);
/*
* Any inode that has dirty modifications in the log is pinned. The
* racy check here for a pinned inode while not catch modifications
* that happen concurrently to the fsync call, but fsync semantics
* only require to sync previously completed I/O.
*/
if (xfs_ipincount(ip))
error = xfs_fsync_flush_log(ip, datasync, &log_flushed);
/*
* If we only have a single device, and the log force about was