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

commit 834ffca6f7e345a79f6f2e2d131b0dfba8a4b67a upstream.

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.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index 64b48ea..6e9d8a0 100644 (file)
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -683,7 +683,15 @@ 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;
        }
 
        /*