xfs: xfs_iflock is no longer a completion

With the recent rework of the inode cluster flushing, we no longer
ever wait on the the inode flush "lock". It was never a lock in the
first place, just a completion to allow callers to wait for inode IO
to complete. We now never wait for flush completion as all inode
flushing is non-blocking. Hence we can get rid of all the iflock
infrastructure and instead just set and check a state flag.

Rename the XFS_IFLOCK flag to XFS_IFLUSHING, convert all the
xfs_iflock_nowait() test-and-set operations on that flag, and
replace all the xfs_ifunlock() calls to clear operations.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

1 files changed, 6 insertions, 5 deletions

diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c
index 0bc623c175e9..5d52249b1fe5 100644
--- a/fs/xfs/xfs_mount.c
+++ b/fs/xfs/xfs_mount.c
@@ -1059,11 +1059,12 @@ xfs_unmountfs(
 	 * We can potentially deadlock here if we have an inode cluster
 	 * that has been freed has its buffer still pinned in memory because
 	 * the transaction is still sitting in a iclog. The stale inodes
-	 * on that buffer will have their flush locks held until the
-	 * transaction hits the disk and the callbacks run. the inode
-	 * flush takes the flush lock unconditionally and with nothing to
-	 * push out the iclog we will never get that unlocked. hence we
-	 * need to force the log first.
+	 * on that buffer will be pinned to the buffer until the
+	 * transaction hits the disk and the callbacks run. Pushing the AIL will
+	 * skip the stale inodes and may never see the pinned buffer, so
+	 * nothing will push out the iclog and unpin the buffer. Hence we
+	 * need to force the log here to ensure all items are flushed into the
+	 * AIL before we go any further.
 	 */
 	xfs_log_force(mp, XFS_LOG_SYNC);