[PATCH v7 17/20] nfsd: fix reply size estimate for GET_DIR_DELEGATION

[Jeff Layton <jlayton@kernel.org>]

nfsd4_get_dir_delegation_rsize() returns its estimate in XDR words, but
the COMPOUND reply-size machinery works in bytes: every other op's
_rsize helper multiplies its word count by sizeof(__be32). Since
GET_DIR_DELEGATION is OP_MODIFIES_SOMETHING, this estimate is consulted
before the op executes to ensure the reply will fit. The ~4x too-small
estimate lets a compound near the session/reply limit pass the check,
grant a directory delegation, and then fail to encode the reply with
NFS4ERR_RESOURCE/REP_TOO_BIG, leaving the client without the returned
stateid.

Multiply the estimate by sizeof(__be32) like the other _rsize helpers.

Fixes: 33a1e6ea73e5 ("nfsd: trivial GET_DIR_DELEGATION support")
Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
 fs/nfsd/nfs4proc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index 565bf76c08ed..be79b6063afe 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -3575,7 +3575,7 @@ static u32 nfsd4_get_dir_delegation_rsize(const struct svc_rqst *rqstp,
 		op_encode_stateid_maxsz +
 		2 /* gddr_notification */ +
 		2 /* gddr_child_attributes */ +
-		2 /* gddr_dir_attributes */);
+		2 /* gddr_dir_attributes */) * sizeof(__be32);
 }
 
 #ifdef CONFIG_NFSD_PNFS

-- 
2.54.0