Hi again,
I posted a version of this patch 4 months and got no reply, so
thought it might be time to try again.
This version includes a small change to handle the case when a
delegation stateid gets a BAD_STATEID, in the context of the open-owner
getting a BAD_SEQID.
Obviously this whole issue can only happen if the server is buggy (or
if the client is buggy, but I don't think it is), but it would be best
to handle that case gracefully. Currently it spins indefinitely.
Thanks,
NeilBrown
From: NeilBrown <neilb@xxxxxxxx>
Subject: [PATCH] NFS: Don't disconnect open-owner on NFS4ERR_BAD_SEQID
When an NFS4ERR_BAD_SEQID is received the open-owner is removed from
the ->state_owners rbtree so that it will no longer be used.
If any stateids attached to this open-owner are still in use, and if a
request using one get an NFS4ERR_BAD_STATEID reply, this can for bad.
The state is marked as needing recovery and the nfs4_state_manager()
is scheduled to clean up. nfs4_state_manager() finds states to be
recovered by walking the state_owners rbtree. As the open-owner is
not in the rbtree, the bad state is not found so nfs4_state_manager()
completes having done nothing. The request is then retried, with a
predicatable result (indefinite retries).
This patch changes NFS4ERR_BAD_SEQID handling to leave the open-owner
in the rbtree but mark it a 'stale'. With this the indefinite retries
no longer happen. Errors get to user-space instead if recovery
doesn't work.
If the stateid is for a delegation, the result is more complex.
nfs4_state_manager() tries to return the delegation but uses the
open-owner with the bad seqid to open files on the server, and this
fails with more BAD_SEQID errors. To avoid this we update the
so_seqid.create_time of the bad open-owner so that it looks to the server
like a new open-owner and an OPEN_CONFIRM is requested. This allows
the return of the delagation to complete.
Signed-off-by: NeilBrown <neilb@xxxxxxxx>
---
fs/nfs/nfs4_fs.h | 3 ++-
fs/nfs/nfs4state.c | 22 +++++++++-------------
2 files changed, 11 insertions(+), 14 deletions(-)
diff --git a/fs/nfs/nfs4_fs.h b/fs/nfs/nfs4_fs.h
index 3f0e459f2499..6be19814553f 100644
--- a/fs/nfs/nfs4_fs.h
+++ b/fs/nfs/nfs4_fs.h
@@ -113,7 +113,8 @@ struct nfs4_state_owner {
enum {
NFS_OWNER_RECLAIM_REBOOT,
- NFS_OWNER_RECLAIM_NOGRACE
+ NFS_OWNER_RECLAIM_NOGRACE,
+ NFS_OWNER_STALE,
};
#define NFS_LOCK_NEW 0
diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c
index 74cc32490c7a..8ed2285fc527 100644
--- a/fs/nfs/nfs4state.c
+++ b/fs/nfs/nfs4state.c
@@ -397,6 +397,8 @@ nfs4_find_state_owner_locked(struct nfs_server *server, struct rpc_cred *cred)
p = &parent->rb_left;
else if (cred > sp->so_cred)
p = &parent->rb_right;
+ else if (test_bit(NFS_OWNER_STALE, &sp->so_flags))
+ p = &parent->rb_left;
else {
if (!list_empty(&sp->so_lru))
list_del_init(&sp->so_lru);
@@ -424,6 +426,8 @@ nfs4_insert_state_owner_locked(struct nfs4_state_owner *new)
p = &parent->rb_left;
else if (new->so_cred > sp->so_cred)
p = &parent->rb_right;
+ else if (test_bit(NFS_OWNER_STALE, &sp->so_flags))
+ p = &parent->rb_left;
else {
if (!list_empty(&sp->so_lru))
list_del_init(&sp->so_lru);
@@ -496,19 +500,11 @@ nfs4_alloc_state_owner(struct nfs_server *server,
static void
nfs4_drop_state_owner(struct nfs4_state_owner *sp)
{
- struct rb_node *rb_node = &sp->so_server_node;
-
- if (!RB_EMPTY_NODE(rb_node)) {
- struct nfs_server *server = sp->so_server;
- struct nfs_client *clp = server->nfs_client;
-
- spin_lock(&clp->cl_lock);
- if (!RB_EMPTY_NODE(rb_node)) {
- rb_erase(rb_node, &server->state_owners);
- RB_CLEAR_NODE(rb_node);
- }
- spin_unlock(&clp->cl_lock);
- }
+ set_bit(NFS_OWNER_STALE, &sp->so_flags);
+ /* Delegation recall might insist on using this open_owner
+ * so reset it to force a new 'confirm' stage to be initiated.
+ */
+ sp->so_seqid.create_time = ktime_get();
}
static void nfs4_free_state_owner(struct nfs4_state_owner *sp)
--
2.10.0
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