kernel/linux.git/fs/dlm/plock.c, branch v6.6.148

dlm: fix plock lookup when using multiple lockspaces

2023-08-25T15:31:39+00:00

All posix lock ops, for all lockspaces (gfs2 file systems) are sent to userspace (dlm_controld) through a single misc device. The dlm_controld daemon reads the ops from the misc device and sends them to other cluster nodes using separate, per-lockspace cluster api communication channels. The ops for a single lockspace are ordered at this level, so that the results are received in the same sequence that the requests were sent. When the results are sent back to the kernel via the misc device, they are again funneled through the single misc device for all lockspaces. When the dlm code in the kernel processes the results from the misc device, these results will be returned in the same sequence that the requests were sent, on a per-lockspace basis. A recent change in this request/reply matching code missed the "per-lockspace" check (fsid comparison) when matching request and reply, so replies could be incorrectly matched to requests from other lockspaces. Cc: stable@vger.kernel.org Reported-by: Barry Marson Fixes: 57e2c2f2d94c ("fs: dlm: fix mismatch of plock results from userspace") Signed-off-by: Alexander Aring Signed-off-by: David Teigland

fs: dlm: add plock dev tracepoints

2023-08-10T15:33:03+00:00

I currently debug nfs plock handling and introduce those two tracepoints for getting more information about what is happening there if the user space reads plock operations from kernel and writing the result back. Signed-off-by: Alexander Aring Signed-off-by: David Teigland

fs: dlm: check on plock ops when exit dlm

2023-08-10T15:33:03+00:00

To be sure we don't have any issues that there are leftover plock ops in either send_list or recv_list we simple check if either one of the list are empty when we exit the dlm subsystem. Signed-off-by: Alexander Aring Signed-off-by: David Teigland

fs: dlm: add missing spin_unlock

2023-08-10T15:33:03+00:00

This patch fixes commit dc52cd2eff4a ("fs: dlm: fix F_CANCELLK to cancel pending request") that we don't unlock the ops_lock in a rate case when a waiter cannot be found. This case can only happen when cancellation of plock operation was successful but no kernel waiter was being found. Fixes: dc52cd2eff4a ("fs: dlm: fix F_CANCELLK to cancel pending request") Signed-off-by: Alexander Aring Signed-off-by: David Teigland

fs: dlm: fix F_CANCELLK to cancel pending request

2023-07-20T22:25:04+00:00

This patch fixes the current handling of F_CANCELLK by not just doing a unlock as we need to try to cancel a lock at first. A unlock makes sense on a non-blocking lock request but if it's a blocking lock request we need to cancel the request until it's not granted yet. This patch is fixing this behaviour by first try to cancel a lock request and if it's failed it's unlocking the lock which seems to be granted. Note: currently the nfs locking handling was disabled by commit 40595cdc93ed ("nfs: block notification on fs with its own ->lock"). However DLM was never being updated regarding to this change. Future patches will try to fix lockd lock requests for DLM. This patch is currently assuming the upstream DLM lockd handling is correct. Signed-off-by: Alexander Aring Signed-off-by: David Teigland

fs: dlm: allow to F_SETLKW getting interrupted

2023-07-20T22:24:57+00:00

This patch implements dlm plock F_SETLKW interruption feature. If a blocking posix lock request got interrupted in user space by a signal a cancellation request for a non granted lock request to the user space lock manager will be send. The user lock manager answers either with zero or a negative errno code. A errno of -ENOENT signals that there is currently no blocking lock request waiting to being granted. In case of -ENOENT it was probably to late to request a cancellation and the pending lock got granted. In any error case we will wait until the lock is being granted as cancellation failed, this causes also that in case of an older user lock manager returning -EINVAL we will wait as cancellation is not supported which should be fine. If a user requires this feature the user should update dlm user space to support lock request cancellation. Signed-off-by: Alexander Aring Signed-off-by: David Teigland

fs: dlm: remove twice newline

2023-07-20T22:24:36+00:00

This patch removes a newline which log_print() already adds, also removes wrapped string that causes a checkpatch warning. Signed-off-by: Alexander Aring Signed-off-by: David Teigland

fs: dlm: fix mismatch of plock results from userspace

2023-05-24T19:27:07+00:00

When a waiting plock request (F_SETLKW) is sent to userspace for processing (dlm_controld), the result is returned at a later time. That result could be incorrectly matched to a different waiting request in cases where the owner field is the same (e.g. different threads in a process.) This is fixed by comparing all the properties in the request and reply. The results for non-waiting plock requests are now matched based on list order because the results are returned in the same order they were sent. Cc: stable@vger.kernel.org Signed-off-by: Alexander Aring Signed-off-by: David Teigland

fs: dlm: make F_SETLK use unkillable wait_event

2023-05-23T17:56:58+00:00

While a non-waiting posix lock request (F_SETLK) is waiting for user space processing (in dlm_controld), wait for that processing to complete with an unkillable wait_event(). This makes F_SETLK behave the same way for F_RDLCK, F_WRLCK and F_UNLCK. F_SETLKW continues to use wait_event_killable(). Cc: stable@vger.kernel.org Signed-off-by: Alexander Aring Signed-off-by: David Teigland

fs: dlm: interrupt posix locks only when process is killed

2023-05-22T19:34:32+00:00

If a posix lock request is waiting for a result from user space (dlm_controld), do not let it be interrupted unless the process is killed. This reverts commit a6b1533e9a57 ("dlm: make posix locks interruptible"). The problem with the interruptible change is that all locks were cleared on any signal interrupt. If a signal was received that did not terminate the process, the process could continue running after all its dlm posix locks had been cleared. A future patch will add cancelation to allow proper interruption. Cc: stable@vger.kernel.org Fixes: a6b1533e9a57 ("dlm: make posix locks interruptible") Signed-off-by: Alexander Aring Signed-off-by: David Teigland