From 568f915655b3b4c40032104e4d0014e5e2c474b9 Mon Sep 17 00:00:00 2001 From: Alexander Aring Date: Thu, 20 Jul 2023 08:22:40 -0400 Subject: fs: dlm: allow to F_SETLKW getting interrupted 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/plock.c | 56 ++++++++++++++++++++++++++++++++++++-------------------- 1 file changed, 36 insertions(+), 20 deletions(-) (limited to 'fs/dlm') diff --git a/fs/dlm/plock.c b/fs/dlm/plock.c index a34f605d8505..a8ffa0760913 100644 --- a/fs/dlm/plock.c +++ b/fs/dlm/plock.c @@ -74,30 +74,26 @@ static void send_op(struct plock_op *op) wake_up(&send_wq); } -/* If a process was killed while waiting for the only plock on a file, - locks_remove_posix will not see any lock on the file so it won't - send an unlock-close to us to pass on to userspace to clean up the - abandoned waiter. So, we have to insert the unlock-close when the - lock call is interrupted. */ - -static void do_unlock_close(const struct dlm_plock_info *info) +static int do_lock_cancel(const struct dlm_plock_info *orig_info) { struct plock_op *op; + int rv; op = kzalloc(sizeof(*op), GFP_NOFS); if (!op) - return; + return -ENOMEM; + + op->info = *orig_info; + op->info.optype = DLM_PLOCK_OP_CANCEL; + op->info.wait = 0; - op->info.optype = DLM_PLOCK_OP_UNLOCK; - op->info.pid = info->pid; - op->info.fsid = info->fsid; - op->info.number = info->number; - op->info.start = 0; - op->info.end = OFFSET_MAX; - op->info.owner = info->owner; - - op->info.flags |= DLM_PLOCK_FL_CLOSE; send_op(op); + wait_event(recv_wq, (op->done != 0)); + + rv = op->info.rv; + + dlm_release_plock_op(op); + return rv; } int dlm_posix_lock(dlm_lockspace_t *lockspace, u64 number, struct file *file, @@ -156,7 +152,7 @@ int dlm_posix_lock(dlm_lockspace_t *lockspace, u64 number, struct file *file, send_op(op); if (op->info.wait) { - rv = wait_event_killable(recv_wq, (op->done != 0)); + rv = wait_event_interruptible(recv_wq, (op->done != 0)); if (rv == -ERESTARTSYS) { spin_lock(&ops_lock); /* recheck under ops_lock if we got a done != 0, @@ -166,17 +162,37 @@ int dlm_posix_lock(dlm_lockspace_t *lockspace, u64 number, struct file *file, spin_unlock(&ops_lock); goto do_lock_wait; } - list_del(&op->list); spin_unlock(&ops_lock); + rv = do_lock_cancel(&op->info); + switch (rv) { + case 0: + /* waiter was deleted in user space, answer will never come + * remove original request. The original request must be + * on recv_list because the answer of do_lock_cancel() + * synchronized it. + */ + spin_lock(&ops_lock); + list_del(&op->list); + spin_unlock(&ops_lock); + rv = -EINTR; + break; + case -ENOENT: + /* cancellation wasn't successful but op should be done */ + fallthrough; + default: + /* internal error doing cancel we need to wait */ + goto wait; + } + log_debug(ls, "%s: wait interrupted %x %llx pid %d", __func__, ls->ls_global_id, (unsigned long long)number, op->info.pid); - do_unlock_close(&op->info); dlm_release_plock_op(op); goto out; } } else { +wait: wait_event(recv_wq, (op->done != 0)); } -- cgit v1.2.3-70-g09d2