xfs: don't zero partial page cache pages during O_DIRECT writes

Similar to direct IO reads, direct IO writes are using 
truncate_pagecache_range to invalidate the page cache. This is
incorrect due to the sub-block zeroing in the page cache that
truncate_pagecache_range() triggers.

This patch fixes things by using invalidate_inode_pages2_range
instead.  It preserves the page cache invalidation, but won't zero
any pages.

cc: stable@vger.kernel.org
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <david@fromorbit.com>

1 files changed, 9 insertions, 1 deletions

diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index 827cfb2451b1..19917faac2d2 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -644,7 +644,15 @@ xfs_file_dio_aio_write(
                                                     pos, -1);
                 if (ret)
                         goto out;
-                truncate_pagecache_range(VFS_I(ip), pos, -1);
+                /*
+                 * Invalidate whole pages. This can return an error if
+                 * we fail to invalidate a page, but this should never
+                 * happen on XFS. Warn if it does fail.
+                 */
+                ret = invalidate_inode_pages2_range(VFS_I(ip)->i_mapping,
+                                                pos >> PAGE_CACHE_SHIFT, -1);
+                WARN_ON_ONCE(ret);
+                ret = 0;
         }
 
         /*