From 41b9d7263ea1e270019c5d04fa0ab15db50b9725 Mon Sep 17 00:00:00 2001 From: Brian Foster Date: Tue, 2 Sep 2014 12:12:53 +1000 Subject: [PATCH] xfs: trim eofblocks before collapse range xfs_collapse_file_space() currently writes back the entire file undergoing collapse range to settle things down for the extent shift algorithm. While this prevents changes to the extent list during the collapse operation, the writeback itself is not enough to prevent unnecessary collapse failures. The current shift algorithm uses the extent index to iterate the in-core extent list. If a post-eof delalloc extent persists after the writeback (e.g., a prior zero range op where the end of the range aligns with eof can separate the post-eof blocks such that they are not written back and converted), xfs_bmap_shift_extents() becomes confused over the encoded br_startblock value and fails the collapse. As with the full writeback, this is a temporary fix until the algorithm is improved to cope with a volatile extent list and avoid attempts to shift post-eof extents. Signed-off-by: Brian Foster Reviewed-by: Dave Chinner Reviewed-by: Christoph Hellwig Signed-off-by: Dave Chinner --- fs/xfs/xfs_bmap_util.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c index 76b6a2910e40..1707980f9a4b 100644 --- a/fs/xfs/xfs_bmap_util.c +++ b/fs/xfs/xfs_bmap_util.c @@ -1471,8 +1471,10 @@ xfs_collapse_file_space( shift_fsb = XFS_B_TO_FSB(mp, len); /* - * writeback the entire file to prevent concurrent writeback of ranges - * outside the collapsing region from changing the extent list. + * Writeback the entire file and force remove any post-eof blocks. The + * writeback prevents changes to the extent list via concurrent + * writeback and the eofblocks trim prevents the extent shift algorithm + * from running into a post-eof delalloc extent. * * XXX: This is a temporary fix until the extent shift loop below is * converted to use offsets and lookups within the ILOCK rather than @@ -1482,6 +1484,11 @@ xfs_collapse_file_space( error = filemap_write_and_wait(VFS_I(ip)->i_mapping); if (error) return error; + if (xfs_can_free_eofblocks(ip, true)) { + error = xfs_free_eofblocks(mp, ip, false); + if (error) + return error; + } error = xfs_free_file_space(ip, offset, len); if (error) -- 2.34.1