[02/25] vfs: vfs_clone_file_prep_inodes should return EINVAL for a clone from beyond EOF

Commit Message

Darrick J. Wong Oct. 11, 2018, 4:12 a.m. UTC

From: Darrick J. Wong <[e-mail]>

vfs_clone_file_prep_inodes cannot return 0 if it is asked to remap from
a zero byte file because that's what btrfs does.

Signed-off-by: Darrick J. Wong <[e-mail]>
---
 fs/read_write.c |    3 ---
 1 file changed, 3 deletions(-)

Comments

'Christoph Hellwig' Oct. 11, 2018, 1:40 p.m. UTC | #1

On Wed, Oct 10, 2018 at 09:12:30PM -0700, Darrick J. Wong wrote:
> From: Darrick J. Wong <[e-mail]>
> 
> vfs_clone_file_prep_inodes cannot return 0 if it is asked to remap from
> a zero byte file because that's what btrfs does.
> 
> Signed-off-by: Darrick J. Wong <[e-mail]>
> ---

Maybe it would be a good time to switch btrfs to use
vfs_clone_file_prep_inodes so that we don't have any discrepancies?

Otherwise looks good:

Reviewed-by: Christoph Hellwig <[e-mail]>

Patch

diff --git a/fs/read_write.c b/fs/read_write.c
index 8a2737f0d61d..260797b01851 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -1740,10 +1740,7 @@  int vfs_clone_file_prep_inodes(struct inode *inode_in, loff_t pos_in,
 	if (!S_ISREG(inode_in->i_mode) || !S_ISREG(inode_out->i_mode))
 		return -EINVAL;
 
-	/* Are we going all the way to the end? */
 	isize = i_size_read(inode_in);
-	if (isize == 0)
-		return 0;
 
 	/* Zero length dedupe exits immediately; reflink goes to EOF. */
 	if (*len == 0) {