cifs: Fix non-availability of dedup breaking generic/304

[ Upstream commit 691a41d8da4b34fe72f09393505f55f28a8f34ec ]

Deduplication isn't supported on cifs, but cifs doesn't reject it, instead
treating it as extent duplication/cloning.  This can cause generic/304 to go
silly and run for hours on end.

Fix cifs to indicate EOPNOTSUPP if REMAP_FILE_DEDUP is set in
->remap_file_range().

Note that it's unclear whether or not commit b073a08016a1 is meant to cause
cifs to return an error if REMAP_FILE_DEDUP.

Fixes: b073a08016a1 ("cifs: fix that return -EINVAL when do dedupe operation")
Cc: stable@vger.kernel.org
Suggested-by: Dave Chinner <david@fromorbit.com>
cc: Xiaoli Feng <fengxiaoli0714@gmail.com>
cc: Shyam Prasad N <nspmangalore@gmail.com>
cc: Rohith Surabattula <rohiths.msft@gmail.com>
cc: Jeff Layton <jlayton@kernel.org>
cc: Darrick Wong <darrick.wong@oracle.com>
cc: fstests@vger.kernel.org
cc: linux-cifs@vger.kernel.org
cc: linux-fsdevel@vger.kernel.org
Link: https://lore.kernel.org/r/3876191.1701555260@warthog.procyon.org.uk/
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index af688e39f31acc8d6ad535059d64dd9c6d01c9e9..9bbead15a028724c87f83f1a5fefb78bd4562cfb 100644 (file)
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -1144,7 +1144,9 @@ static loff_t cifs_remap_file_range(struct file *src_file, loff_t off,
        unsigned int xid;
        int rc;
 
-       if (remap_flags & ~(REMAP_FILE_DEDUP | REMAP_FILE_ADVISORY))
+       if (remap_flags & REMAP_FILE_DEDUP)
+               return -EOPNOTSUPP;
+       if (remap_flags & ~REMAP_FILE_ADVISORY)
                return -EINVAL;
 
        cifs_dbg(FYI, "clone range\n");