From: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
If we're asked to recover open state while a delegation return is
outstanding, then the state manager thread cannot use a cached open, so
if the server returns a delegation, we can end up deadlocked behind the
pending delegreturn.
To avoid this problem, let's just ask the server not to give us a
delegation unless we're explicitly reclaiming one.
Fixes: be36e185bd26 ("NFSv4: nfs4_open_recover_helper() must set share access")
Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
---
fs/nfs/nfs4proc.c | 19 ++++++++++++++-----
1 file changed, 14 insertions(+), 5 deletions(-)
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index bd89c7f06952..c002e4b69761 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -2131,18 +2131,27 @@ static struct nfs4_opendata *nfs4_open_recoverdata_alloc(struct nfs_open_context
}
static int nfs4_open_recover_helper(struct nfs4_opendata *opendata,
- fmode_t fmode)
+ fmode_t fmode)
{
struct nfs4_state *newstate;
+ struct nfs_server *server = NFS_SB(opendata->dentry->d_sb);
+ int openflags = 0;
int ret;
if (!nfs4_mode_match_open_stateid(opendata->state, fmode))
return 0;
- opendata->o_arg.open_flags = 0;
+ /*
+ * If we're not recovering a delegation, then ask for no delegation.
+ * Otherwise the recovery thread could deadlock with an outstanding
+ * delegation return.
+ */
+ if (opendata->o_arg.u.delegation_type == 0)
+ openflags = O_DIRECT;
+
+ opendata->o_arg.open_flags = openflags;
opendata->o_arg.fmode = fmode;
- opendata->o_arg.share_access = nfs4_map_atomic_open_share(
- NFS_SB(opendata->dentry->d_sb),
- fmode, 0);
+ opendata->o_arg.share_access =
+ nfs4_map_atomic_open_share(server, fmode, openflags);
memset(&opendata->o_res, 0, sizeof(opendata->o_res));
memset(&opendata->c_res, 0, sizeof(opendata->c_res));
nfs4_init_opendata_res(opendata);
--
2.38.1
