[1/2] xfs: factor range zeroing out of xfs_free_file_space

Commit Message

Eric Sandeen June 25, 2019, 12:45 a.m. UTC

Factor out the range zeroing part of xfs_free_file_space into
a new function, xfs_zero_range, which is a wrapper around
iomap_zero_range + EOF handling.

Signed-off-by: Eric Sandeen <[e-mail]>
---

Patch

diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c
index 2a7e10f26bb0..0a96c4d1718e 100644
--- a/fs/xfs/xfs_bmap_util.c
+++ b/fs/xfs/xfs_bmap_util.c
@@ -1061,6 +1061,37 @@  xfs_flush_unmap_range(
 	return 0;
 }
 
+/*
+ * Ensure that the specified range is all zeros.
+ * Unmapped or unwritten blocks are left alone by the iomap mechanism,
+ * as they already return zero on read.
+ * This will happily extend i_size if asked to do so.
+ */
+static int
+xfs_zero_range(
+	struct xfs_inode	*ip,
+	xfs_off_t		offset,
+	xfs_off_t		len)
+{
+	int			error;
+
+	error = iomap_zero_range(VFS_I(ip), offset, len, NULL, &xfs_iomap_ops);
+	if (error)
+		return error;
+	/*
+	 * If we zeroed right up to EOF and EOF straddles a page boundary we
+	 * must make sure that the post-EOF area is also zeroed because the
+	 * page could be mmap'd and iomap_zero_range doesn't do that for us.
+	 * Writeback of the eof page will do this, albeit clumsily.
+	 */
+	if (offset + len >= XFS_ISIZE(ip) && offset_in_page(offset + len) > 0) {
+		error = filemap_write_and_wait_range(VFS_I(ip)->i_mapping,
+				round_down(offset + len, PAGE_SIZE), LLONG_MAX);
+	}
+
+	return error;
+}
+
 int
 xfs_free_file_space(
 	struct xfs_inode	*ip,
@@ -1101,28 +1132,15 @@  xfs_free_file_space(
 	}
 
 	/*
-	 * Now that we've unmap all full blocks we'll have to zero out any
-	 * partial block at the beginning and/or end.  iomap_zero_range is smart
-	 * enough to skip any holes, including those we just created, but we
-	 * must take care not to zero beyond EOF and enlarge i_size.
-	 */
-	if (offset >= XFS_ISIZE(ip))
-		return 0;
-	if (offset + len > XFS_ISIZE(ip))
-		len = XFS_ISIZE(ip) - offset;
-	error = iomap_zero_range(VFS_I(ip), offset, len, NULL, &xfs_iomap_ops);
-	if (error)
-		return error;
-
-	/*
-	 * If we zeroed right up to EOF and EOF straddles a page boundary we
-	 * must make sure that the post-EOF area is also zeroed because the
-	 * page could be mmap'd and iomap_zero_range doesn't do that for us.
-	 * Writeback of the eof page will do this, albeit clumsily.
+	 * Now that we've unmapped all full blocks we'll have to zero out any
+	 * partial block at the beginning and/or end.  xfs_zero_range is smart
+	 * enough to skip any holes, including those we just created.  We don't
+	 * want to zero beyond EOF and enlarge i_size.
 	 */
-	if (offset + len >= XFS_ISIZE(ip) && offset_in_page(offset + len) > 0) {
-		error = filemap_write_and_wait_range(VFS_I(ip)->i_mapping,
-				round_down(offset + len, PAGE_SIZE), LLONG_MAX);
+	if (offset < XFS_ISIZE(ip)) {
+		if (offset + len > XFS_ISIZE(ip))
+			len = XFS_ISIZE(ip) - offset;
+		error = xfs_zero_range(ip, offset, len);
 	}
 
 	return error;