From dc52cd2eff4ac924a795efcef27f8fd58a5260bb Mon Sep 17 00:00:00 2001 From: Alexander Aring Date: Thu, 20 Jul 2023 08:22:41 -0400 Subject: fs: dlm: fix F_CANCELLK to cancel pending request 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/plock.c | 103 +++++++++++++++++++++++++++++++++++++++++++++++++-------- 1 file changed, 90 insertions(+), 13 deletions(-) (limited to 'fs/dlm') diff --git a/fs/dlm/plock.c b/fs/dlm/plock.c index a8ffa0760913..943d9f8e5564 100644 --- a/fs/dlm/plock.c +++ b/fs/dlm/plock.c @@ -42,6 +42,27 @@ static inline void set_version(struct dlm_plock_info *info) info->version[2] = DLM_PLOCK_VERSION_PATCH; } +static struct plock_op *plock_lookup_waiter(const struct dlm_plock_info *info) +{ + struct plock_op *op = NULL, *iter; + + list_for_each_entry(iter, &recv_list, list) { + if (iter->info.fsid == info->fsid && + iter->info.number == info->number && + iter->info.owner == info->owner && + iter->info.pid == info->pid && + iter->info.start == info->start && + iter->info.end == info->end && + iter->info.ex == info->ex && + iter->info.wait) { + op = iter; + break; + } + } + + return op; +} + static int check_version(struct dlm_plock_info *info) { if ((DLM_PLOCK_VERSION_MAJOR != info->version[0]) || @@ -334,6 +355,74 @@ out: } EXPORT_SYMBOL_GPL(dlm_posix_unlock); +/* + * NOTE: This implementation can only handle async lock requests as nfs + * do it. It cannot handle cancellation of a pending lock request sitting + * in wait_event(), but for now only nfs is the only user local kernel + * user. + */ +int dlm_posix_cancel(dlm_lockspace_t *lockspace, u64 number, struct file *file, + struct file_lock *fl) +{ + struct dlm_plock_info info; + struct plock_op *op; + struct dlm_ls *ls; + int rv; + + /* this only works for async request for now and nfs is the only + * kernel user right now. + */ + if (WARN_ON_ONCE(!fl->fl_lmops || !fl->fl_lmops->lm_grant)) + return -EOPNOTSUPP; + + ls = dlm_find_lockspace_local(lockspace); + if (!ls) + return -EINVAL; + + memset(&info, 0, sizeof(info)); + info.pid = fl->fl_pid; + info.ex = (fl->fl_type == F_WRLCK); + info.fsid = ls->ls_global_id; + dlm_put_lockspace(ls); + info.number = number; + info.start = fl->fl_start; + info.end = fl->fl_end; + info.owner = (__u64)fl->fl_pid; + + rv = do_lock_cancel(&info); + switch (rv) { + case 0: + spin_lock(&ops_lock); + /* lock request to cancel must be on recv_list because + * do_lock_cancel() synchronizes it. + */ + op = plock_lookup_waiter(&info); + if (WARN_ON_ONCE(!op)) { + rv = -ENOLCK; + break; + } + + list_del(&op->list); + spin_unlock(&ops_lock); + WARN_ON(op->info.optype != DLM_PLOCK_OP_LOCK); + op->data->callback(op->data->fl, -EINTR); + dlm_release_plock_op(op); + rv = -EINTR; + break; + case -ENOENT: + /* if cancel wasn't successful we probably were to late + * or it was a non-blocking lock request, so just unlock it. + */ + rv = dlm_posix_unlock(lockspace, number, file, fl); + break; + default: + break; + } + + return rv; +} +EXPORT_SYMBOL_GPL(dlm_posix_cancel); + int dlm_posix_get(dlm_lockspace_t *lockspace, u64 number, struct file *file, struct file_lock *fl) { @@ -457,19 +546,7 @@ static ssize_t dev_write(struct file *file, const char __user *u, size_t count, */ spin_lock(&ops_lock); if (info.wait) { - list_for_each_entry(iter, &recv_list, list) { - if (iter->info.fsid == info.fsid && - iter->info.number == info.number && - iter->info.owner == info.owner && - iter->info.pid == info.pid && - iter->info.start == info.start && - iter->info.end == info.end && - iter->info.ex == info.ex && - iter->info.wait) { - op = iter; - break; - } - } + op = plock_lookup_waiter(&info); } else { list_for_each_entry(iter, &recv_list, list) { if (!iter->info.wait) { -- cgit v1.2.3