BMC/Intel-BMC/linux.git/fs/nfsd/nfs4callback.c, branch dev

nfsd: Update callback sequnce id only CB_SEQUENCE success

2015-06-04T20:51:30+00:00

When testing pnfs layout, nfsd got error NFS4ERR_SEQ_MISORDERED. It is caused by nfs return NFS4ERR_DELAY before validate_seqid(), don't update the sequnce id, but nfsd updates the sequnce id !!! According to RFC5661 20.9.3, " If CB_SEQUENCE returns an error, then the state of the slot (sequence ID, cached reply) MUST NOT change. " Signed-off-by: Kinglong Mee Signed-off-by: J. Bruce Fields

nfsd: Reset cb_status in nfsd4_cb_prepare() at retrying

2015-06-04T20:43:39+00:00

nfsd enters a infinite loop and prints message every 10 seconds: May 31 18:33:52 test-server kernel: Error sending entire callback! May 31 18:34:01 test-server kernel: Error sending entire callback! This is caused by a cb_layoutreturn getting error -10008 (NFS4ERR_DELAY), the client crashing, and then nfsd entering the infinite loop: bc_sendto --> call_timeout --> nfsd4_cb_done --> nfsd4_cb_layout_done with error -10008 --> rpc_delay(task, HZ/100) --> bc_sendto ... Reproduced using xfstests 074 with nfs client's kdump on, CONFIG_DEFAULT_HUNG_TASK_TIMEOUT set, and client's blkmapd down: 1. nfs client's write operation will get the layout of file, and then send getdeviceinfo, 2. but layout segment is not recorded by client because blkmapd is down, 3. client writes data by sending WRITE to server, 4. nfs server recalls the layout of the file before WRITE, 5. network error causes the client reset the session and return NFS4ERR_DELAY, 6. so client's WRITE operation is waiting the reply. If the task hangs 120s, the client will crash. 7. so that, the next bc_sendto will fail with TIMEOUT, and cb_status is NFS4ERR_DELAY. Signed-off-by: Kinglong Mee Signed-off-by: J. Bruce Fields

nfsd: skip CB_NULL probes for 4.1 or later

2015-05-04T16:02:42+00:00

With sessions in v4.1 or later we don't need to manually probe the backchannel connection, so we can declare it up instantly after setting up the RPC client. Note that we really should split nfsd4_run_cb_work in the long run, this is just the least intrusive fix for now. Signed-off-by: Christoph Hellwig Signed-off-by: J. Bruce Fields

nfsd: fix callback restarts

2015-05-04T16:02:41+00:00

Checking the rpc_client pointer is not a reliable way to detect backchannel changes: cl_cb_client is changed only after shutting down the rpc client, so the condition cl_cb_client = tk_client will always be true. Check the RPC_TASK_KILLED flag instead, and rewrite the code to avoid the buggy cl_callbacks list and fix the lifetime rules due to double calls of the ->prepare callback operations method for this retry case. Signed-off-by: Christoph Hellwig Signed-off-by: J. Bruce Fields

nfsd: split transport vs operation errors for callbacks

2015-05-04T16:02:40+00:00

We must only increment the sequence id if the client has seen and responded to a request. If we failed to deliver it to the client we must resend with the same sequence id. So just like the client track errors at the transport level differently from those returned in the XDR. Signed-off-by: Christoph Hellwig Signed-off-by: J. Bruce Fields

nfsd: implement pNFS layout recalls

2015-02-02T17:09:43+00:00

Add support to issue layout recalls to clients. For now we only support full-file recalls to get a simple and stable implementation. This allows to embedd a nfsd4_callback structure in the layout_state and thus avoid any memory allocations under spinlocks during a recall. For normal use cases that do not intent to share a single file between multiple clients this implementation is fully sufficient. To ensure layouts are recalled on local filesystem access each layout state registers a new FL_LAYOUT lease with the kernel file locking code, which filesystems that support pNFS exports that require recalls need to break on conflicting access patterns. The XDR code is based on the old pNFS server implementation by Andy Adamson, Benny Halevy, Boaz Harrosh, Dean Hildebrand, Fred Isaman, Marc Eshel, Mike Sager and Ricardo Labiaga. Signed-off-by: Christoph Hellwig

nfsd: Fix slot wake up race in the nfsv4.1 callback code

2014-11-19T20:45:44+00:00

The currect code for nfsd41_cb_get_slot() and nfsd4_cb_done() has no locking in order to guarantee atomicity, and so allows for races of the form. Task 1 Task 2 ====== ====== if (test_and_set_bit(0) != 0) { clear_bit(0) rpc_wake_up_next(queue) rpc_sleep_on(queue) return false; } This patch breaks the race condition by adding a retest of the bit after the call to rpc_sleep_on(). Signed-off-by: Trond Myklebust Cc: stable@vger.kernel.org Signed-off-by: J. Bruce Fields

nfsd: eliminate "to_delegation" define

2014-10-01T16:28:01+00:00

We now have cb_to_delegation and to_delegation, which do the same thing and are defined separately in different .c files. Move the cb_to_delegation definition into a header file and eliminate the redundant to_delegation definition. Reviewed-by: Christoph Hellwig Signed-off-by: Jeff Layton

nfsd: introduce nfsd4_callback_ops

2014-09-26T20:29:29+00:00

Add a higher level abstraction than the rpc_ops for callback operations. Signed-off-by: Christoph Hellwig Reviewed-by: Jeff Layton Signed-off-by: J. Bruce Fields

nfsd: split nfsd4_callback initialization and use

2014-09-26T20:29:28+00:00

Split out initializing the nfs4_callback structure from using it. For the NULL callback this gets rid of tons of pointless re-initializations. Note that I don't quite understand what protects us from running multiple NULL callbacks at the same time, but at least this chance doesn't make it worse.. Signed-off-by: Christoph Hellwig Reviewed-by: Jeff Layton Signed-off-by: J. Bruce Fields