xfs: zeroing space needs to punch delalloc blocks

When we are zeroing space andit is covered by a delalloc range, we
need to punch the delalloc range out before we truncate the page
cache. Failing to do so leaves and inconsistency between the page
cache and the extent tree, which we later trip over when doing
direct IO over the same range.
Signed-off-by: NDave Chinner <dchinner@redhat.com>
Tested-by: NBrian Foster <bfoster@redhat.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NDave Chinner <david@fromorbit.com>

fs/xfs/xfs_bmap_util.c

@@ -1418,6 +1418,8 @@ xfs_zero_file_space(
 	xfs_off_t		end_boundary;
 	int			error;
 
+	trace_xfs_zero_file_space(ip);
+
 	granularity = max_t(uint, 1 << mp->m_sb.sb_blocklog, PAGE_CACHE_SIZE);
 
 	/*
@@ -1432,9 +1434,18 @@ xfs_zero_file_space(
 	ASSERT(end_boundary <= offset + len);
 
 	if (start_boundary < end_boundary - 1) {
-		/* punch out the page cache over the conversion range */
+		/*
+		 * punch out delayed allocation blocks and the page cache over
+		 * the conversion range
+		 */
+		xfs_ilock(ip, XFS_ILOCK_EXCL);
+		error = xfs_bmap_punch_delalloc_range(ip,
+				XFS_B_TO_FSBT(mp, start_boundary),
+				XFS_B_TO_FSB(mp, end_boundary - start_boundary));
+		xfs_iunlock(ip, XFS_ILOCK_EXCL);
 		truncate_pagecache_range(VFS_I(ip), start_boundary,
 					 end_boundary - 1);
+
 		/* convert the blocks */
 		error = xfs_alloc_file_space(ip, start_boundary,
 					end_boundary - start_boundary - 1,

fs/xfs/xfs_trace.h

@@ -603,6 +603,7 @@ DEFINE_INODE_EVENT(xfs_readlink);
 DEFINE_INODE_EVENT(xfs_inactive_symlink);
 DEFINE_INODE_EVENT(xfs_alloc_file_space);
 DEFINE_INODE_EVENT(xfs_free_file_space);
+DEFINE_INODE_EVENT(xfs_zero_file_space);
 DEFINE_INODE_EVENT(xfs_collapse_file_space);
 DEFINE_INODE_EVENT(xfs_readdir);
 #ifdef CONFIG_XFS_POSIX_ACL