kernel/linux.git/fs/nfs/callback.c, branch v6.18.21

SUNRPC: Move the svc_rpcb_cleanup() call sites

2025-09-23T17:28:19+00:00

Clean up: because svc_rpcb_cleanup() and svc_xprt_destroy_all() are always invoked in pairs, we can deduplicate code by moving the svc_rpcb_cleanup() call sites into svc_xprt_destroy_all(). Signed-off-by: Chuck Lever Tested-by: Olga Kornievskaia Signed-off-by: Anna Schumaker

NFS: Remove rpcbind cleanup for NFSv4.0 callback

2025-09-23T17:28:19+00:00

The NFS client's NFSv4.0 callback listeners are created with SVC_SOCK_ANONYMOUS, therefore svc_setup_socket() does not register them with the client's rpcbind service. And, note that nfs_callback_down_net() does not call svc_rpcb_cleanup() at all when shutting down the callback server. Even if svc_setup_socket() were to attempt to register or unregister these sockets, the callback service has vs_hidden set, which shunts the rpcbind upcalls. The svc_rpcb_cleanup() error flow was introduced by commit c946556b8749 ("NFS: move per-net callback thread initialization to nfs_callback_up_net()"). It doesn't appear in the code that was relocated by that commit. Therefore, there is no need to call svc_rpcb_cleanup() when listener creation fails during callback server start-up. Signed-off-by: Chuck Lever Signed-off-by: Anna Schumaker

nfsd: don't use sv_nrthreads in connection limiting calculations.

2025-01-06T14:37:36+00:00

The heuristic for limiting the number of incoming connections to nfsd currently uses sv_nrthreads - allowing more connections if more threads were configured. A future patch will allow number of threads to grow dynamically so that there will be no need to configure sv_nrthreads. So we need a different solution for limiting connections. It isn't clear what problem is solved by limiting connections (as mentioned in a code comment) but the most likely problem is a connection storm - many connections that are not doing productive work. These will be closed after about 6 minutes already but it might help to slow down a storm. This patch adds a per-connection flag XPT_PEER_VALID which indicates that the peer has presented a filehandle for which it has some sort of access. i.e the peer is known to be trusted in some way. We now only count connections which have NOT been determined to be valid. There should be relative few of these at any given time. If the number of non-validated peer exceed a limit - currently 64 - we close the oldest non-validated peer to avoid having too many of these useless connections. Note that this patch significantly changes the meaning of the various configuration parameters for "max connections". The next patch will remove all of these. Signed-off-by: NeilBrown Reviewed-by: Jeff Layton Signed-off-by: Chuck Lever

sunrpc: allow svc threads to fail initialisation cleanly

2024-09-20T23:31:03+00:00

If an svc thread needs to perform some initialisation that might fail, it has no good way to handle the failure. Before the thread can exit it must call svc_exit_thread(), but that requires the service mutex to be held. The thread cannot simply take the mutex as that could deadlock if there is a concurrent attempt to shut down all threads (which is unlikely, but not impossible). nfsd currently call svc_exit_thread() unprotected in the unlikely event that unshare_fs_struct() fails. We can clean this up by introducing svc_thread_init_status() by which an svc thread can report whether initialisation has succeeded. If it has, it continues normally into the action loop. If it has not, svc_thread_init_status() immediately aborts the thread. svc_start_kthread() waits for either of these to happen, and calls svc_exit_thread() (under the mutex) if the thread aborted. Signed-off-by: NeilBrown Reviewed-by: Jeff Layton Signed-off-by: Chuck Lever

nfsd: stop setting ->pg_stats for unused stats

2024-03-01T14:12:08+00:00

A lot of places are setting a blank svc_stats in ->pg_stats and never utilizing these stats. Remove all of these extra structs as we're not reporting these stats anywhere. Signed-off-by: Josef Bacik Reviewed-by: Jeff Layton Signed-off-by: Chuck Lever

SUNRPC: discard sv_refcnt, and svc_get/svc_put

2024-01-07T22:54:33+00:00

sv_refcnt is no longer useful. lockd and nfs-cb only ever have the svc active when there are a non-zero number of threads, so sv_refcnt mirrors sv_nrthreads. nfsd also keeps the svc active between when a socket is added and when the first thread is started, but we don't really need a refcount for that. We can simply not destroy the svc while there are any permanent sockets attached. So remove sv_refcnt and the get/put functions. Instead of a final call to svc_put(), call svc_destroy() instead. This is changed to also store NULL in the passed-in pointer to make it easier to avoid use-after-free situations. Signed-off-by: NeilBrown Reviewed-by: Jeff Layton Signed-off-by: Chuck Lever

SUNRPC: change how svc threads are asked to exit.

2023-10-16T16:44:04+00:00

svc threads are currently stopped using kthread_stop(). This requires identifying a specific thread. However we don't care which thread stops, just as long as one does. So instead, set a flag in the svc_pool to say that a thread needs to die, and have each thread check this flag instead of calling kthread_should_stop(). The first thread to find and clear this flag then moves towards exiting. This removes an explicit dependency on sp_all_threads which will make a future patch simpler. Signed-off-by: NeilBrown Signed-off-by: Chuck Lever

SUNRPC: integrate back-channel processing with svc_recv()

2023-10-16T16:44:03+00:00

Using svc_recv() for (NFSv4.1) back-channel handling means we have just one mechanism for waking threads. Also change kthread_freezable_should_stop() in nfs4_callback_svc() to kthread_should_stop() as used elsewhere. kthread_freezable_should_stop() effectively adds a try_to_freeze() call, and svc_recv() already contains that at an appropriate place. Signed-off-by: NeilBrown Cc: Trond Myklebust Cc: Anna Schumaker Signed-off-by: Chuck Lever

SUNRPC: Clean up bc_svc_process()

2023-10-16T16:44:03+00:00

The test robot complained that, in some build configurations, the @error variable in bc_svc_process's only caller is set but never used. This happens because dprintk() is the only consumer of that value. - Remove the dprintk() call sites in favor of the svc_process tracepoint - The @error variable and the return value of bc_svc_process() are now unused, so get rid of them. - The @serv parameter is set to rqstp->rq_serv by the only caller, and bc_svc_process() then uses it only to set rqstp->rq_serv. It can be removed. - Rename bc_svc_process() according to the convention that globally-visible RPC server functions have names that begin with "svc_"; and because it is globally-visible, give it a proper kdoc comment. Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-kbuild-all/202308121314.HA8Rq2XG-lkp@intel.com/ Signed-off-by: Chuck Lever

SUNRPC: Add enum svc_auth_status

2023-08-29T21:45:22+00:00

In addition to the benefits of using an enum rather than a set of macros, we now have a named type that can improve static type checking of function return values. As part of this change, I removed a stale comment from svcauth.h; the return values from current implementations of the auth_ops::release method are all zero/negative errno, not the SVC_OK enum values as the old comment suggested. Suggested-by: NeilBrown Signed-off-by: Chuck Lever