From 549054afadae44889c0b40d4c3bfb0207b98d5a0 Mon Sep 17 00:00:00 2001 From: David Chinner Date: Sat, 10 Feb 2007 18:36:35 +1100 Subject: [PATCH] [XFS] Fix sub-block zeroing for buffered writes into unwritten extents. When writing less than a filesystem block of data into an unwritten extent via buffered I/O, __xfs_get_blocks fails to set the buffer new flag. As a result, the generic code will not zero either edge of the block resulting in garbage being written to disk either side of the real data. Set the buffer new state on bufferd writes to unwritten extents to ensure that zeroing occurs. SGI-PV: 960328 SGI-Modid: xfs-linux-melb:xfs-kern:28000a Signed-off-by: David Chinner Signed-off-by: Lachlan McIlroy Signed-off-by: Tim Shimmin --- fs/xfs/linux-2.6/xfs_aops.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) diff --git a/fs/xfs/linux-2.6/xfs_aops.c b/fs/xfs/linux-2.6/xfs_aops.c index 9761a5befef0..f3cc4ab20ba0 100644 --- a/fs/xfs/linux-2.6/xfs_aops.c +++ b/fs/xfs/linux-2.6/xfs_aops.c @@ -1283,13 +1283,18 @@ __xfs_get_blocks( bh_result->b_bdev = iomap.iomap_target->bt_bdev; /* - * If we previously allocated a block out beyond eof and we are - * now coming back to use it then we will need to flag it as new - * even if it has a disk address. + * If we previously allocated a block out beyond eof and we are now + * coming back to use it then we will need to flag it as new even if it + * has a disk address. + * + * With sub-block writes into unwritten extents we also need to mark + * the buffer as new so that the unwritten parts of the buffer gets + * correctly zeroed. */ if (create && ((!buffer_mapped(bh_result) && !buffer_uptodate(bh_result)) || - (offset >= i_size_read(inode)) || (iomap.iomap_flags & IOMAP_NEW))) + (offset >= i_size_read(inode)) || + (iomap.iomap_flags & (IOMAP_NEW|IOMAP_UNWRITTEN)))) set_buffer_new(bh_result); if (iomap.iomap_flags & IOMAP_DELAY) { -- GitLab