[PATCH AUTOSEL for 4.4 019/167] NFSv4.1: Work around a Linux server bug...

Sasha Levin
2018-03-19T17:33:05Z

From: Trond Myklebust <trond.myklebust@primarydata.com>

[ Upstream commit f4b23de3dda1536590787c9e5c3d16b8738ab108 ]

It turns out the Linux server has a bug in its implementation of
supattr_exclcreat; it returns the set of all attributes, whether
or not they are supported by minor version 1.
In order to avoid a regression, we therefore apply the supported_attrs
as a mask on top of whatever the server sent us.

Reported-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
---
fs/nfs/nfs4proc.c | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index bcfddfc7a1f4..0f397e62de5a 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -3025,6 +3025,7 @@ static int _nfs4_server_capabilities(struct nfs_server *server, struct nfs_fh *f
.rpc_resp = &res,
};
int status;
+ int i;

bitmask[0] = FATTR4_WORD0_SUPPORTED_ATTRS |
FATTR4_WORD0_FH_EXPIRE_TYPE |
@@ -3090,8 +3091,13 @@ static int _nfs4_server_capabilities(struct nfs_server *server, struct nfs_fh *f
server->cache_consistency_bitmask[0] &= FATTR4_WORD0_CHANGE|FATTR4_WORD0_SIZE;
server->cache_consistency_bitmask[1] &= FATTR4_WORD1_TIME_METADATA|FATTR4_WORD1_TIME_MODIFY;
server->cache_consistency_bitmask[2] = 0;
+
+ /* Avoid a regression due to buggy server */
+ for (i = 0; i < ARRAY_SIZE(res.exclcreat_bitmask); i++)
+ res.exclcreat_bitmask[i] &= res.attr_bitmask[i];
memcpy(server->exclcreat_bitmask, res.exclcreat_bitmask,
sizeof(server->exclcreat_bitmask));
+
server->acl_bitmask = res.acl_bitmask;
server->fh_expire_type = res.fh_expire_type;
}
--
2.14.1