vf/remap: return the amount of bytes actually deduplicated

When using the FIDEDUPRANGE ioctl, in case of success the requested size
is returned. In some cases this might not be the actual amount of bytes
deduplicated.

This change modifies vfs_dedupe_file_range() to report the actual amount
of bytes deduplicated, instead of the requested amount.

Link: https://lore.kernel.org/linux-fsdevel/5548ef63-62f9-4f46-5793-03165ceccacc@tu-darmstadt.de/
Reported-by: Ansgar Lößer <ansgar.loesser@kom.tu-darmstadt.de>
Reported-by: Max Schlecht <max.schlecht@informatik.hu-berlin.de>
Reported-by: Björn Scheuermann <scheuermann@kom.tu-darmstadt.de>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Darrick J Wong <djwong@kernel.org>
Signed-off-by: Ansgar Lößer <ansgar.loesser@kom.tu-darmstadt.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/fs/remap_range.c b/fs/remap_range.c
index 881a306ee2473ddccde84367eadd7701b074403e..5e0d97e02f9681e5049789cf68835fd1fa0d9ac6 100644 (file)
--- a/fs/remap_range.c
+++ b/fs/remap_range.c
@@ -547,7 +547,7 @@ int vfs_dedupe_file_range(struct file *file, struct file_dedupe_range *same)
                else if (deduped < 0)
                        info->status = deduped;
                else
-                       info->bytes_deduped = len;
+                       info->bytes_deduped = deduped;
 
 next_fdput:
                fdput(dst_fd);