xfs: only writeback and truncate pages for the freed range

xfs_free_file_space() only affects the range of the file for which space
is being freed. It currently writes and truncates the page cache from
the start offset of the free to EOF.

Modify xfs_free_file_space() to write back and truncate page cache of
just the range being freed.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

1 files changed, 6 insertions, 4 deletions

diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c
index eae763f4600e..809ae7d395c3 100644
--- a/fs/xfs/xfs_bmap_util.c
+++ b/fs/xfs/xfs_bmap_util.c
@@ -1205,6 +1205,7 @@ xfs_free_file_space(
         xfs_bmap_free_t         free_list;
         xfs_bmbt_irec_t         imap;
         xfs_off_t               ioffset;
+        xfs_off_t               iendoffset;
         xfs_extlen_t            mod=0;
         xfs_mount_t             *mp;
         int                     nimap;
@@ -1233,12 +1234,13 @@ xfs_free_file_space(
         inode_dio_wait(VFS_I(ip));
 
         rounding = max_t(xfs_off_t, 1 << mp->m_sb.sb_blocklog, PAGE_CACHE_SIZE);
-        ioffset = offset & ~(rounding - 1);
-        error = filemap_write_and_wait_range(VFS_I(ip)->i_mapping,
-                                              ioffset, -1);
+        ioffset = round_down(offset, rounding);
+        iendoffset = round_up(offset + len, rounding) - 1;
+        error = filemap_write_and_wait_range(VFS_I(ip)->i_mapping, ioffset,
+                                             iendoffset);
         if (error)
                 goto out;
-        truncate_pagecache_range(VFS_I(ip), ioffset, -1);
+        truncate_pagecache_range(VFS_I(ip), ioffset, iendoffset);
 
         /*
          * Need to zero the stuff we're not freeing, on disk.