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authorJeff Layton <jlayton@kernel.org>2024-04-05 19:56:18 +0200
committerChuck Lever <chuck.lever@oracle.com>2024-04-05 20:05:35 +0200
commit10396f4df8b75ff6ab0aa2cd74296565466f2c8d (patch)
treec34f457c0e65e8a90841638b1f09d458d044c040 /fs/nfsd/nfs4state.c
parentSUNRPC: Fix a slow server-side memory leak with RPC-over-TCP (diff)
downloadlinux-10396f4df8b75ff6ab0aa2cd74296565466f2c8d.tar.xz
linux-10396f4df8b75ff6ab0aa2cd74296565466f2c8d.zip
nfsd: hold a lighter-weight client reference over CB_RECALL_ANY
Currently the CB_RECALL_ANY job takes a cl_rpc_users reference to the client. While a callback job is technically an RPC that counter is really more for client-driven RPCs, and this has the effect of preventing the client from being unhashed until the callback completes. If nfsd decides to send a CB_RECALL_ANY just as the client reboots, we can end up in a situation where the callback can't complete on the (now dead) callback channel, but the new client can't connect because the old client can't be unhashed. This usually manifests as a NFS4ERR_DELAY return on the CREATE_SESSION operation. The job is only holding a reference to the client so it can clear a flag after the RPC completes. Fix this by having CB_RECALL_ANY instead hold a reference to the cl_nfsdfs.cl_ref. Typically we only take that sort of reference when dealing with the nfsdfs info files, but it should work appropriately here to ensure that the nfs4_client doesn't disappear. Fixes: 44df6f439a17 ("NFSD: add delegation reaper to react to low memory condition") Reported-by: Vladimir Benes <vbenes@redhat.com> Signed-off-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Diffstat (limited to '')
-rw-r--r--fs/nfsd/nfs4state.c7
1 files changed, 2 insertions, 5 deletions
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 5fcd93f7cb8c..3cef81e196c6 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -3042,12 +3042,9 @@ static void
nfsd4_cb_recall_any_release(struct nfsd4_callback *cb)
{
struct nfs4_client *clp = cb->cb_clp;
- struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);
- spin_lock(&nn->client_lock);
clear_bit(NFSD4_CLIENT_CB_RECALL_ANY, &clp->cl_flags);
- put_client_renew_locked(clp);
- spin_unlock(&nn->client_lock);
+ drop_client(clp);
}
static int
@@ -6616,7 +6613,7 @@ deleg_reaper(struct nfsd_net *nn)
list_add(&clp->cl_ra_cblist, &cblist);
/* release in nfsd4_cb_recall_any_release */
- atomic_inc(&clp->cl_rpc_users);
+ kref_get(&clp->cl_nfsdfs.cl_ref);
set_bit(NFSD4_CLIENT_CB_RECALL_ANY, &clp->cl_flags);
clp->cl_ra_time = ktime_get_boottime_seconds();
}