[PATCH 06/25] vfs: skip zero-length dedupe requests

[Darrick J. Wong]

From: Darrick J. Wong <darrick.w...@oracle.com>

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.w...@oracle.com>
Reviewed-by: Christoph Hellwig <h...@lst.de>
Reviewed-by: Amir Goldstein <amir7...@gmail.com>
---
 fs/read_write.c |    5 +++++
 1 file changed, 5 insertions(+)


diff --git a/fs/read_write.c b/fs/read_write.c
index 067ff5698e0b..2d84d18dc095 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -1991,6 +1991,11 @@ 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);
 out_drop_write: