[PATCH 07/25] vfs: skip zero-length dedupe requests

Darrick J. Wong
2018-10-10T00:11:27Z

Don't bother calling the filesystem for a zero-length dedupe request;
we can return zero and exit.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
fs/read_write.c | 5 +++++
1 file changed, 5 insertions(+)

diff --git a/fs/read_write.c b/fs/read_write.c
index f7b728d4972f..3ff90b3315fb 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -1975,6 +1975,11 @@ int vfs_dedupe_file_range_one(struct file *src_file, loff_t src_pos,
if (!dst_file->f_op->dedupe_file_range)
goto out_drop_write;

+ if (len == 0) {
+ ret = 0;
+ goto out_drop_write;
+ }
+
ret = dst_file->f_op->dedupe_file_range(src_file, src_pos,
dst_file, dst_pos, len);