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| author |   Trond Myklebust <trond.myklebust@hammerspace.com> | 2021-06-01 11:10:05 -0400 |
|---|---|---|
| committer | Trond Myklebust <trond.myklebust@hammerspace.com> | 2021-06-03 10:14:42 -0400 |
| commit | dfe1fe75e00e4c724ede7b9e593f6f680e446c5f (patch) | |
| tree | 2a74d5f01498891b11d85c89085737df12838413 /fs/nfs | |
| parent | NFS: FMODE_READ and friends are C macros, not enum types (diff) | |
| download | linux-dev-dfe1fe75e00e4c724ede7b9e593f6f680e446c5f.tar.xz linux-dev-dfe1fe75e00e4c724ede7b9e593f6f680e446c5f.zip | |
NFSv4: Fix deadlock between nfs4_evict_inode() and nfs4_opendata_get_inode()
If the inode is being evicted, but has to return a delegation first,
then it can cause a deadlock in the corner case where the server reboots
before the delegreturn completes, but while the call to iget5_locked() in
nfs4_opendata_get_inode() is waiting for the inode free to complete.
Since the open call still holds a session slot, the reboot recovery
cannot proceed.
In order to break the logjam, we can turn the delegation return into a
privileged operation for the case where we're evicting the inode. We
know that in that case, there can be no other state recovery operation
that conflicts.
Reported-by: zhangxiaoxu (A) <zhangxiaoxu5@huawei.com>
Fixes: 5fcdfacc01f3 ("NFSv4: Return delegations synchronously in evict_inode")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Diffstat (limited to 'fs/nfs')
| -rw-r--r-- | fs/nfs/nfs4_fs.h | 1 | ||||
| -rw-r--r-- | fs/nfs/nfs4proc.c | 12 |
2 files changed, 12 insertions, 1 deletions
diff --git a/fs/nfs/nfs4_fs.h b/fs/nfs/nfs4_fs.h index 065cb04222a1..543d916f79ab 100644 --- a/fs/nfs/nfs4_fs.h +++ b/fs/nfs/nfs4_fs.h @@ -205,6 +205,7 @@ struct nfs4_exception { struct inode *inode; nfs4_stateid *stateid; long timeout; + unsigned char task_is_privileged : 1; unsigned char delay : 1, recovering : 1, retry : 1; diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c index 7e63fbe253f0..cf85f0ed1e06 100644 --- a/fs/nfs/nfs4proc.c +++ b/fs/nfs/nfs4proc.c @@ -589,6 +589,8 @@ int nfs4_handle_exception(struct nfs_server *server, int errorcode, struct nfs4_ goto out_retry; } if (exception->recovering) { + if (exception->task_is_privileged) + return -EDEADLOCK; ret = nfs4_wait_clnt_recover(clp); if (test_bit(NFS_MIG_FAILED, &server->mig_status)) return -EIO; @@ -614,6 +616,8 @@ nfs4_async_handle_exception(struct rpc_task *task, struct nfs_server *server, goto out_retry; } if (exception->recovering) { + if (exception->task_is_privileged) + return -EDEADLOCK; rpc_sleep_on(&clp->cl_rpcwaitq, task, NULL); if (test_bit(NFS4CLNT_MANAGER_RUNNING, &clp->cl_state) == 0) rpc_wake_up_queued_task(&clp->cl_rpcwaitq, task); @@ -6417,6 +6421,7 @@ static void nfs4_delegreturn_done(struct rpc_task *task, void *calldata) struct nfs4_exception exception = { .inode = data->inode, .stateid = &data->stateid, + .task_is_privileged = data->args.seq_args.sa_privileged, }; if (!nfs4_sequence_done(task, &data->res.seq_res)) @@ -6540,7 +6545,6 @@ static int _nfs4_proc_delegreturn(struct inode *inode, const struct cred *cred, data = kzalloc(sizeof(*data), GFP_NOFS); if (data == NULL) return -ENOMEM; - nfs4_init_sequence(&data->args.seq_args, &data->res.seq_res, 1, 0); nfs4_state_protect(server->nfs_client, NFS_SP4_MACH_CRED_CLEANUP, @@ -6571,6 +6575,12 @@ static int _nfs4_proc_delegreturn(struct inode *inode, const struct cred *cred, } } + if (!data->inode) + nfs4_init_sequence(&data->args.seq_args, &data->res.seq_res, 1, + 1); + else + nfs4_init_sequence(&data->args.seq_args, &data->res.seq_res, 1, + 0); task_setup_data.callback_data = data; msg.rpc_argp = &data->args; msg.rpc_resp = &data->res; |