xfs: remove leftover CoW reservations when remounting ro

When we're remounting the filesystem readonly, remove all CoW preallocations prior to going ro. If the fs goes down after the ro remount, we never clean up the staging extents, which means xfs_check will trip over them on a subsequent run. Practically speaking, the next mount will clean them up too, so this is unlikely to be seen. Since we shut down the cowblocks cleaner on remount-ro, we also have to make sure we start it back up if/when we remount-rw. Found by adding clonerange to fsstress and running xfs/017. Signed-off-by: Darrick J. Wong <[email protected]> Reviewed-by: Dave Chinner <[email protected]> Reviewed-by: Christoph Hellwig <[email protected]>
jangid · Dec 21, 2017 · 10ddf64 · 10ddf64
1 parent 363e59b
commit 10ddf64
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Showing 3 changed files with 11 additions and 1 deletion.
diff --git a/fs/xfs/xfs_icache.c b/fs/xfs/xfs_icache.c
@@ -870,7 +870,7 @@ xfs_eofblocks_worker(
  * based on the 'speculative_cow_prealloc_lifetime' tunable (5m by default).
  * (We'll just piggyback on the post-EOF prealloc space workqueue.)
  */
-STATIC void
+void
 xfs_queue_cowblocks(
 	struct xfs_mount *mp)
 {

diff --git a/fs/xfs/xfs_icache.h b/fs/xfs/xfs_icache.h
@@ -81,6 +81,7 @@ void xfs_inode_clear_cowblocks_tag(struct xfs_inode *ip);
 int xfs_icache_free_cowblocks(struct xfs_mount *, struct xfs_eofblocks *);
 int xfs_inode_free_quota_cowblocks(struct xfs_inode *ip);
 void xfs_cowblocks_worker(struct work_struct *);
+void xfs_queue_cowblocks(struct xfs_mount *);
 
 int xfs_inode_ag_iterator(struct xfs_mount *mp,
 	int (*execute)(struct xfs_inode *ip, int flags, void *args),

diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
@@ -1360,6 +1360,7 @@ xfs_fs_remount(
 			xfs_force_shutdown(mp, SHUTDOWN_CORRUPT_INCORE);
 			return error;
 		}
+		xfs_queue_cowblocks(mp);
 
 		/* Create the per-AG metadata reservation pool .*/
 		error = xfs_fs_reserve_ag_blocks(mp);
@@ -1369,6 +1370,14 @@ xfs_fs_remount(
 
 	/* rw -> ro */
 	if (!(mp->m_flags & XFS_MOUNT_RDONLY) && (*flags & MS_RDONLY)) {
+		/* Get rid of any leftover CoW reservations... */
+		cancel_delayed_work_sync(&mp->m_cowblocks_work);
+		error = xfs_icache_free_cowblocks(mp, NULL);
+		if (error) {
+			xfs_force_shutdown(mp, SHUTDOWN_CORRUPT_INCORE);
+			return error;
+		}
+
 		/* Free the per-AG metadata reservation pool. */
 		error = xfs_fs_unreserve_ag_blocks(mp);
 		if (error) {