From: Trond Myklebust trond.myklebust@hammerspace.com
[ Upstream commit aeabb3c96186a0f944fc2b1f25c84d5eb3a93fa9 ]
Fix a deadlock whereby the NFSv4 state manager can get stuck in the delegation return code, waiting for a layout return to complete in another thread. If the server reboots before that other thread completes, then we need to be able to start a second state manager thread in order to perform recovery.
Signed-off-by: Trond Myklebust trond.myklebust@hammerspace.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/nfs/nfs4_fs.h | 2 ++ fs/nfs/nfs4state.c | 16 +++++++++++----- 2 files changed, 13 insertions(+), 5 deletions(-)
diff --git a/fs/nfs/nfs4_fs.h b/fs/nfs/nfs4_fs.h index 3a6904173214..63287d911c08 100644 --- a/fs/nfs/nfs4_fs.h +++ b/fs/nfs/nfs4_fs.h @@ -41,6 +41,8 @@ enum nfs4_client_state { NFS4CLNT_MOVED, NFS4CLNT_LEASE_MOVED, NFS4CLNT_DELEGATION_EXPIRED, + NFS4CLNT_RUN_MANAGER, + NFS4CLNT_DELEGRETURN_RUNNING, };
#define NFS4_RENEW_TIMEOUT 0x01 diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c index 18920152da14..d2f645d34eb1 100644 --- a/fs/nfs/nfs4state.c +++ b/fs/nfs/nfs4state.c @@ -1210,6 +1210,7 @@ void nfs4_schedule_state_manager(struct nfs_client *clp) struct task_struct *task; char buf[INET6_ADDRSTRLEN + sizeof("-manager") + 1];
+ set_bit(NFS4CLNT_RUN_MANAGER, &clp->cl_state); if (test_and_set_bit(NFS4CLNT_MANAGER_RUNNING, &clp->cl_state) != 0) return; __module_get(THIS_MODULE); @@ -2485,6 +2486,7 @@ static void nfs4_state_manager(struct nfs_client *clp)
/* Ensure exclusive access to NFSv4 state */ do { + clear_bit(NFS4CLNT_RUN_MANAGER, &clp->cl_state); if (test_bit(NFS4CLNT_PURGE_STATE, &clp->cl_state)) { section = "purge state"; status = nfs4_purge_lease(clp); @@ -2575,14 +2577,18 @@ static void nfs4_state_manager(struct nfs_client *clp) }
nfs4_end_drain_session(clp); - if (test_and_clear_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state)) { - nfs_client_return_marked_delegations(clp); - continue; + nfs4_clear_state_manager_bit(clp); + + if (!test_and_set_bit(NFS4CLNT_DELEGRETURN_RUNNING, &clp->cl_state)) { + if (test_and_clear_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state)) { + nfs_client_return_marked_delegations(clp); + set_bit(NFS4CLNT_RUN_MANAGER, &clp->cl_state); + } + clear_bit(NFS4CLNT_DELEGRETURN_RUNNING, &clp->cl_state); }
- nfs4_clear_state_manager_bit(clp); /* Did we race with an attempt to give us more work? */ - if (clp->cl_state == 0) + if (!test_bit(NFS4CLNT_RUN_MANAGER, &clp->cl_state)) return; if (test_and_set_bit(NFS4CLNT_MANAGER_RUNNING, &clp->cl_state) != 0) return;