[PATCH 4.9 39/78] xfs: free cowblocks and retry on buffered write ENOSPC

[Greg Kroah-Hartman]

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------


From: Brian Foster <bfoster@xxxxxxxxxx>

commit cf2cb7845d6e101cb17bd62f8aa08cd514fc8988 upstream.

XFS runs an eofblocks reclaim scan before returning an ENOSPC error to
userspace for buffered writes. This facilitates aggressive speculative
preallocation without causing user visible side effects such as
premature ENOSPC.

Run a cowblocks scan in the same situation to reclaim lingering COW fork
preallocation throughout the filesystem.

Signed-off-by: Brian Foster <bfoster@xxxxxxxxxx>
Reviewed-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 fs/xfs/xfs_file.c |    1 +
 1 file changed, 1 insertion(+)

--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -729,6 +729,7 @@ write_retry:
 		xfs_rw_iunlock(ip, iolock);
 		eofb.eof_flags = XFS_EOF_FLAGS_SYNC;
 		xfs_icache_free_eofblocks(ip->i_mount, &eofb);
+		xfs_icache_free_cowblocks(ip->i_mount, &eofb);
 		goto write_retry;
 	}