From 024adf48702212b0af15c682a7ff9773e1e092d6 Mon Sep 17 00:00:00 2001 From: "Darrick J. Wong" Date: Mon, 10 Oct 2016 16:47:40 +1100 Subject: [PATCH] xfs: reduce stack usage of _reflink_clear_inode_flag 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 Reported-by: Brian Foster Reviewed-by: Dave Chinner Signed-off-by: Dave Chinner --- fs/xfs/xfs_reflink.c | 40 ++++++++++++++++------------------------ 1 file changed, 16 insertions(+), 24 deletions(-) diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c index 9c58b4a83248..c4e35dccb803 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; } /* -- 2.39.5