kernel/linux.git/fs/lockd/svclock.c, branch v6.12.81

lockd: fix vfs_test_lock() calls

2026-01-08T09:14:49+00:00

commit a49a2a1baa0c553c3548a1c414b6a3c005a8deba upstream. Usage of vfs_test_lock() is somewhat confused. Documentation suggests it is given a "lock" but this is not the case. It is given a struct file_lock which contains some details of the sort of lock it should be looking for. In particular passing a "file_lock" containing fl_lmops or fl_ops is meaningless and possibly confusing. This is particularly problematic in lockd. nlmsvc_testlock() receives an initialised "file_lock" from xdr-decode, including manager ops and an owner. It then mistakenly passes this to vfs_test_lock() which might replace the owner and the ops. This can lead to confusion when freeing the lock. The primary role of the 'struct file_lock' passed to vfs_test_lock() is to report a conflicting lock that was found, so it makes more sense for nlmsvc_testlock() to pass "conflock", which it uses for returning the conflicting lock. With this change, freeing of the lock is not confused and code in __nlm4svc_proc_test() and __nlmsvc_proc_test() can be simplified. Documentation for vfs_test_lock() is improved to reflect its real purpose, and a WARN_ON_ONCE() is added to avoid a similar problem in the future. Reported-by: Olga Kornievskaia Closes: https://lore.kernel.org/all/20251021130506.45065-1-okorniev@redhat.com Signed-off-by: NeilBrown Fixes: 20fa19027286 ("nfs: add export operations") Cc: stable@vger.kernel.org Reviewed-by: Jeff Layton Signed-off-by: Chuck Lever Signed-off-by: Greg Kroah-Hartman

lockd: adapt to breakup of struct file_lock

2024-02-05T12:11:43+00:00

Most of the existing APIs have remained the same, but subsystems that access file_lock fields directly need to reach into struct file_lock_core now. Signed-off-by: Jeff Layton Link: https://lore.kernel.org/r/20240131-flsplit-v3-40-c6129007ee8d@kernel.org Reviewed-by: NeilBrown Signed-off-by: Christian Brauner

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

lockd: fix race in async lock request handling

2023-10-16T16:44:02+00:00

This patch fixes a race in async lock request handling between adding the relevant struct nlm_block to nlm_blocked list after the request was sent by vfs_lock_file() and nlmsvc_grant_deferred() does a lookup of the nlm_block in the nlm_blocked list. It could be that the async request is completed before the nlm_block was added to the list. This would end in a -ENOENT and a kernel log message of "lockd: grant for unknown block". To solve this issue we add the nlm_block before the vfs_lock_file() call to be sure it has been added when a possible nlmsvc_grant_deferred() is called. If the vfs_lock_file() results in an case when it wouldn't be added to nlm_blocked list, the nlm_block struct will be removed from this list again. Reviewed-by: Jeff Layton Signed-off-by: Alexander Aring Signed-off-by: Chuck Lever

lockd: don't call vfs_lock_file() for pending requests

2023-10-16T16:44:01+00:00

This patch returns nlm_lck_blocked in nlmsvc_lock() when an asynchronous lock request is pending. During testing I ran into the case with the side-effects that lockd is waiting for only one lm_grant() callback because it's already part of the nlm_blocked list. If another asynchronous for the same nlm_block is triggered two lm_grant() callbacks will occur but lockd was only waiting for one. To avoid any change of existing users this handling will only being made when export_op_support_safe_async_lock() returns true. Reviewed-by: Jeff Layton Signed-off-by: Alexander Aring Signed-off-by: Chuck Lever

lockd: introduce safe async lock op

2023-10-16T16:44:01+00:00

This patch reverts mostly commit 40595cdc93ed ("nfs: block notification on fs with its own ->lock") and introduces an EXPORT_OP_ASYNC_LOCK export flag to signal that the "own ->lock" implementation supports async lock requests. The only main user is DLM that is used by GFS2 and OCFS2 filesystem. Those implement their own lock() implementation and return FILE_LOCK_DEFERRED as return value. Since commit 40595cdc93ed ("nfs: block notification on fs with its own ->lock") the DLM implementation were never updated. This patch should prepare for DLM to set the EXPORT_OP_ASYNC_LOCK export flag and update the DLM plock implementation regarding to it. Acked-by: Jeff Layton Signed-off-by: Alexander Aring Signed-off-by: Chuck Lever

SUNRPC: remove timeout arg from svc_recv()

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

Most svc threads have no interest in a timeout. nfsd sets it to 1 hour, but this is a wart of no significance. lockd uses the timeout so that it can call nlmsvc_retry_blocked(). It also sometimes calls svc_wake_up() to ensure this is called. So change lockd to be consistent and always use svc_wake_up() to trigger nlmsvc_retry_blocked() - using a timer instead of a timeout to svc_recv(). And change svc_recv() to not take a timeout arg. This makes the sp_threads_timedout counter always zero. Signed-off-by: NeilBrown Signed-off-by: Chuck Lever

lockd: nlm_blocked list race fixes

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

This patch fixes races when lockd accesses the global nlm_blocked list. It was mostly safe to access the list because everything was accessed from the lockd kernel thread context but there exist cases like nlmsvc_grant_deferred() that could manipulate the nlm_blocked list and it can be called from any context. Signed-off-by: Alexander Aring Reviewed-by: Jeff Layton Signed-off-by: Chuck Lever

lockd: server should unlock lock if client rejects the grant

2023-04-26T13:05:00+00:00

Currently lockd just dequeues the block and ignores it if the client sends a GRANT_RES with a status of nlm_lck_denied. That status is an indicator that the client has rejected the lock, so the right thing to do is to unlock the lock we were trying to grant. Reported-by: Yongcheng Yang Link: https://bugzilla.redhat.com/show_bug.cgi?id=2063818 Signed-off-by: Jeff Layton Signed-off-by: Chuck Lever

lockd: fix file selection in nlmsvc_cancel_blocked

2022-12-10T16:01:11+00:00

We currently do a lock_to_openmode call based on the arguments from the NLM_UNLOCK call, but that will always set the fl_type of the lock to F_UNLCK, and the O_RDONLY descriptor is always chosen. Fix it to use the file_lock from the block instead. Signed-off-by: Jeff Layton Signed-off-by: Chuck Lever