diff mbox

[3/7] xfs: reduce stack usage of _reflink_clear_inode_flag

Message ID 147588165809.12127.6624984020251009472.stgit@birch.djwong.org
State Accepted
Headers show

Commit Message

Darrick J. Wong Oct. 7, 2016, 11:07 p.m. UTC
The loop in _reflink_clear_inode_flag isn't necessary since we
jump out if any part of any extent is shared.  Remove the loop
and we no longer need two maps, so we can save some stack use.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reported-by: Brian Foster <bfoster@redhat.com>
---
 fs/xfs/xfs_reflink.c |   40 ++++++++++++++++------------------------
 1 file changed, 16 insertions(+), 24 deletions(-)



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diff mbox

Patch

diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c
index 9c58b4a..c4e35dc 100644
--- a/fs/xfs/xfs_reflink.c
+++ b/fs/xfs/xfs_reflink.c
@@ -1507,7 +1507,7 @@  xfs_reflink_clear_inode_flag(
 	xfs_extlen_t		aglen;
 	xfs_agblock_t		rbno;
 	xfs_extlen_t		rlen;
-	struct xfs_bmbt_irec	map[2];
+	struct xfs_bmbt_irec	map;
 	int			nmaps;
 	int			error = 0;
 
@@ -1521,37 +1521,29 @@  xfs_reflink_clear_inode_flag(
 		 * Look for extents in the file.  Skip holes, delalloc, or
 		 * unwritten extents; they can't be reflinked.
 		 */
-		error = xfs_bmapi_read(ip, fbno, end - fbno, map, &nmaps, 0);
+		error = xfs_bmapi_read(ip, fbno, end - fbno, &map, &nmaps, 0);
 		if (error)
 			return error;
 		if (nmaps == 0)
 			break;
-		if (map[0].br_startblock == HOLESTARTBLOCK ||
-		    map[0].br_startblock == DELAYSTARTBLOCK ||
-		    ISUNWRITTEN(&map[0]))
+		if (map.br_startblock == HOLESTARTBLOCK ||
+		    map.br_startblock == DELAYSTARTBLOCK ||
+		    ISUNWRITTEN(&map))
 			goto next;
 
-		map[1] = map[0];
-		while (map[1].br_blockcount) {
-			agno = XFS_FSB_TO_AGNO(mp, map[1].br_startblock);
-			agbno = XFS_FSB_TO_AGBNO(mp, map[1].br_startblock);
-			aglen = map[1].br_blockcount;
-
-			error = xfs_reflink_find_shared(mp, agno, agbno, aglen,
-					&rbno, &rlen, false);
-			if (error)
-				return error;
-			/* Is there still a shared block here? */
-			if (rbno != NULLAGBLOCK)
-				return 0;
-
-			map[1].br_blockcount -= aglen;
-			map[1].br_startoff += aglen;
-			map[1].br_startblock += aglen;
-		}
+		agno = XFS_FSB_TO_AGNO(mp, map.br_startblock);
+		agbno = XFS_FSB_TO_AGBNO(mp, map.br_startblock);
+		aglen = map.br_blockcount;
 
+		error = xfs_reflink_find_shared(mp, agno, agbno, aglen,
+				&rbno, &rlen, false);
+		if (error)
+			return error;
+		/* Is there still a shared block here? */
+		if (rbno != NULLAGBLOCK)
+			return 0;
 next:
-		fbno = map[0].br_startoff + map[0].br_blockcount;
+		fbno = map.br_startoff + map.br_blockcount;
 	}
 
 	/*