diff options
Diffstat (limited to 'xlators/features/locks/src/entrylk.c')
| -rw-r--r-- | xlators/features/locks/src/entrylk.c | 1153 |
1 files changed, 1153 insertions, 0 deletions
diff --git a/xlators/features/locks/src/entrylk.c b/xlators/features/locks/src/entrylk.c new file mode 100644 index 00000000000..fd772c850dd --- /dev/null +++ b/xlators/features/locks/src/entrylk.c @@ -0,0 +1,1153 @@ +/* + Copyright (c) 2006-2012 Red Hat, Inc. <http://www.redhat.com> + This file is part of GlusterFS. + + This file is licensed to you under your choice of the GNU Lesser + General Public License, version 3 or any later version (LGPLv3 or + later), or the GNU General Public License, version 2 (GPLv2), in all + cases as published by the Free Software Foundation. +*/ +#include <glusterfs/glusterfs.h> +#include <glusterfs/compat.h> +#include <glusterfs/xlator.h> +#include <glusterfs/logging.h> +#include <glusterfs/common-utils.h> +#include <glusterfs/list.h> +#include <glusterfs/upcall-utils.h> + +#include "locks.h" +#include "clear.h" +#include "common.h" +#include "pl-messages.h" + +void +__pl_entrylk_unref(pl_entry_lock_t *lock) +{ + lock->ref--; + if (!lock->ref) { + GF_FREE((char *)lock->basename); + GF_FREE(lock->connection_id); + GF_FREE(lock); + } +} + +static void +__pl_entrylk_ref(pl_entry_lock_t *lock) +{ + lock->ref++; +} + +static pl_entry_lock_t * +new_entrylk_lock(pl_inode_t *pinode, const char *basename, entrylk_type type, + const char *domain, call_frame_t *frame, char *conn_id, + int32_t *op_errno) +{ + pl_entry_lock_t *newlock = NULL; + + if (!pl_is_lk_owner_valid(&frame->root->lk_owner, frame->root->client)) { + *op_errno = EINVAL; + goto out; + } + + newlock = GF_CALLOC(1, sizeof(pl_entry_lock_t), + gf_locks_mt_pl_entry_lock_t); + if (!newlock) { + *op_errno = ENOMEM; + goto out; + } + + newlock->basename = basename ? gf_strdup(basename) : NULL; + newlock->type = type; + newlock->client = frame->root->client; + newlock->client_pid = frame->root->pid; + newlock->volume = domain; + newlock->owner = frame->root->lk_owner; + newlock->frame = frame; + newlock->this = frame->this; + + if (conn_id) { + newlock->connection_id = gf_strdup(conn_id); + } + + INIT_LIST_HEAD(&newlock->domain_list); + INIT_LIST_HEAD(&newlock->blocked_locks); + INIT_LIST_HEAD(&newlock->client_list); + + __pl_entrylk_ref(newlock); +out: + return newlock; +} + +/** + * all_names - does a basename represent all names? + * @basename: name to check + */ + +#define all_names(basename) ((basename == NULL) ? 1 : 0) + +/** + * names_conflict - do two names conflict? + * @n1: name + * @n2: name + */ + +static int +names_conflict(const char *n1, const char *n2) +{ + return all_names(n1) || all_names(n2) || !strcmp(n1, n2); +} + +static int +__same_entrylk_owner(pl_entry_lock_t *l1, pl_entry_lock_t *l2) +{ + return (is_same_lkowner(&l1->owner, &l2->owner) && + (l1->client == l2->client)); +} + +/* Just as in inodelk, allow conflicting name locks from same (lk_owner, conn)*/ +static int +__conflicting_entrylks(pl_entry_lock_t *l1, pl_entry_lock_t *l2) +{ + if (names_conflict(l1->basename, l2->basename) && + !__same_entrylk_owner(l1, l2)) + return 1; + + return 0; +} + +/* See comments in inodelk.c for details */ +static inline gf_boolean_t +__stale_entrylk(xlator_t *this, pl_entry_lock_t *candidate_lock, + pl_entry_lock_t *requested_lock, time_t *lock_age_sec) +{ + posix_locks_private_t *priv = NULL; + + priv = this->private; + + /* Question: Should we just prune them all given the + * chance? Or just the locks we are attempting to acquire? + */ + if (names_conflict(candidate_lock->basename, requested_lock->basename)) { + *lock_age_sec = gf_time() - candidate_lock->granted_time; + if (*lock_age_sec > priv->revocation_secs) + return _gf_true; + } + return _gf_false; +} + +/* See comments in inodelk.c for details */ +static gf_boolean_t +__entrylk_prune_stale(xlator_t *this, pl_inode_t *pinode, pl_dom_list_t *dom, + pl_entry_lock_t *lock) +{ + posix_locks_private_t *priv = NULL; + pl_entry_lock_t *tmp = NULL; + pl_entry_lock_t *lk = NULL; + gf_boolean_t revoke_lock = _gf_false; + int bcount = 0; + int gcount = 0; + int op_errno = 0; + clrlk_args args; + args.opts = NULL; + time_t lk_age_sec = 0; + uint32_t max_blocked = 0; + char *reason_str = NULL; + + priv = this->private; + args.type = CLRLK_ENTRY; + if (priv->revocation_clear_all == _gf_true) + args.kind = CLRLK_ALL; + else + args.kind = CLRLK_GRANTED; + + if (list_empty(&dom->entrylk_list)) + goto out; + + pthread_mutex_lock(&pinode->mutex); + lock->pinode = pinode; + list_for_each_entry_safe(lk, tmp, &dom->entrylk_list, domain_list) + { + if (__stale_entrylk(this, lk, lock, &lk_age_sec) == _gf_true) { + revoke_lock = _gf_true; + reason_str = "age"; + break; + } + } + max_blocked = priv->revocation_max_blocked; + if (max_blocked != 0 && revoke_lock == _gf_false) { + list_for_each_entry_safe(lk, tmp, &dom->blocked_entrylks, blocked_locks) + { + max_blocked--; + if (max_blocked == 0) { + revoke_lock = _gf_true; + reason_str = "max blocked"; + break; + } + } + } + pthread_mutex_unlock(&pinode->mutex); + +out: + if (revoke_lock == _gf_true) { + clrlk_clear_entrylk(this, pinode, dom, &args, &bcount, &gcount, + &op_errno); + gf_log(this->name, GF_LOG_WARNING, + "Lock revocation [reason: %s; gfid: %s; domain: %s; " + "age: %ld sec] - Entry lock revoked: %d granted & %d " + "blocked locks cleared", + reason_str, uuid_utoa(pinode->gfid), dom->domain, lk_age_sec, + gcount, bcount); + } + + return revoke_lock; +} + +void +entrylk_contention_notify_check(xlator_t *this, pl_entry_lock_t *lock, + struct timespec *now, struct list_head *contend) +{ + posix_locks_private_t *priv; + int64_t elapsed; + + priv = this->private; + + /* If this lock is in a list, it means that we are about to send a + * notification for it, so no need to do anything else. */ + if (!list_empty(&lock->contend)) { + return; + } + + elapsed = now->tv_sec; + elapsed -= lock->contention_time.tv_sec; + if (now->tv_nsec < lock->contention_time.tv_nsec) { + elapsed--; + } + if (elapsed < priv->notify_contention_delay) { + return; + } + + /* All contention notifications will be sent outside of the locked + * region. This means that currently granted locks might have already + * been unlocked by that time. To avoid the lock or the inode to be + * destroyed before we process them, we take an additional reference + * on both. */ + inode_ref(lock->pinode->inode); + __pl_entrylk_ref(lock); + + lock->contention_time = *now; + + list_add_tail(&lock->contend, contend); +} + +void +entrylk_contention_notify(xlator_t *this, struct list_head *contend) +{ + struct gf_upcall up; + struct gf_upcall_entrylk_contention lc; + pl_entry_lock_t *lock; + pl_inode_t *pl_inode; + client_t *client; + gf_boolean_t notify; + + while (!list_empty(contend)) { + lock = list_first_entry(contend, pl_entry_lock_t, contend); + + pl_inode = lock->pinode; + + pthread_mutex_lock(&pl_inode->mutex); + + /* If the lock has already been released, no notification is + * sent. We clear the notification time in this case. */ + notify = !list_empty(&lock->domain_list); + if (!notify) { + lock->contention_time.tv_sec = 0; + lock->contention_time.tv_nsec = 0; + } else { + lc.type = lock->type; + lc.name = lock->basename; + lc.pid = lock->client_pid; + lc.domain = lock->volume; + lc.xdata = NULL; + + gf_uuid_copy(up.gfid, lock->pinode->gfid); + client = (client_t *)lock->client; + if (client == NULL) { + /* A NULL client can be found if the entrylk + * was issued by a server side xlator. */ + up.client_uid = NULL; + } else { + up.client_uid = client->client_uid; + } + } + + pthread_mutex_unlock(&pl_inode->mutex); + + if (notify) { + up.event_type = GF_UPCALL_ENTRYLK_CONTENTION; + up.data = &lc; + + if (this->notify(this, GF_EVENT_UPCALL, &up) < 0) { + gf_msg_debug(this->name, 0, + "Entrylk contention notification " + "failed"); + } else { + gf_msg_debug(this->name, 0, + "Entrylk contention notification " + "sent"); + } + } + + pthread_mutex_lock(&pl_inode->mutex); + + list_del_init(&lock->contend); + __pl_entrylk_unref(lock); + + pthread_mutex_unlock(&pl_inode->mutex); + + inode_unref(pl_inode->inode); + } +} + +/** + * entrylk_grantable - is this lock grantable? + * @inode: inode in which to look + * @basename: name we're trying to lock + * @type: type of lock + */ +static pl_entry_lock_t * +__entrylk_grantable(xlator_t *this, pl_dom_list_t *dom, pl_entry_lock_t *lock, + struct timespec *now, struct list_head *contend) +{ + pl_entry_lock_t *tmp = NULL; + pl_entry_lock_t *ret = NULL; + + list_for_each_entry(tmp, &dom->entrylk_list, domain_list) + { + if (__conflicting_entrylks(tmp, lock)) { + if (ret == NULL) { + ret = tmp; + if (contend == NULL) { + break; + } + } + entrylk_contention_notify_check(this, tmp, now, contend); + } + } + + return ret; +} + +static pl_entry_lock_t * +__blocked_entrylk_conflict(pl_dom_list_t *dom, pl_entry_lock_t *lock) +{ + pl_entry_lock_t *tmp = NULL; + + list_for_each_entry(tmp, &dom->blocked_entrylks, blocked_locks) + { + if (names_conflict(tmp->basename, lock->basename)) + return lock; + } + + return NULL; +} + +static int +__owner_has_lock(pl_dom_list_t *dom, pl_entry_lock_t *newlock) +{ + pl_entry_lock_t *lock = NULL; + + list_for_each_entry(lock, &dom->entrylk_list, domain_list) + { + if (__same_entrylk_owner(lock, newlock)) + return 1; + } + + list_for_each_entry(lock, &dom->blocked_entrylks, blocked_locks) + { + if (__same_entrylk_owner(lock, newlock)) + return 1; + } + + return 0; +} + +static int +names_equal(const char *n1, const char *n2) +{ + return (n1 == NULL && n2 == NULL) || (n1 && n2 && !strcmp(n1, n2)); +} + +void +pl_print_entrylk(char *str, int size, entrylk_cmd cmd, entrylk_type type, + const char *basename, const char *domain) +{ + char *cmd_str = NULL; + char *type_str = NULL; + + switch (cmd) { + case ENTRYLK_LOCK: + cmd_str = "LOCK"; + break; + + case ENTRYLK_LOCK_NB: + cmd_str = "LOCK_NB"; + break; + + case ENTRYLK_UNLOCK: + cmd_str = "UNLOCK"; + break; + + default: + cmd_str = "UNKNOWN"; + break; + } + + switch (type) { + case ENTRYLK_RDLCK: + type_str = "READ"; + break; + case ENTRYLK_WRLCK: + type_str = "WRITE"; + break; + default: + type_str = "UNKNOWN"; + break; + } + + snprintf(str, size, + "lock=ENTRYLK, cmd=%s, type=%s, basename=%s, domain: %s", cmd_str, + type_str, basename, domain); +} + +void +entrylk_trace_in(xlator_t *this, call_frame_t *frame, const char *domain, + fd_t *fd, loc_t *loc, const char *basename, entrylk_cmd cmd, + entrylk_type type) +{ + posix_locks_private_t *priv = NULL; + char pl_locker[256]; + char pl_lockee[256]; + char pl_entrylk[256]; + + priv = this->private; + + if (!priv->trace) + return; + + pl_print_locker(pl_locker, 256, this, frame); + pl_print_lockee(pl_lockee, 256, fd, loc); + pl_print_entrylk(pl_entrylk, 256, cmd, type, basename, domain); + + gf_log(this->name, GF_LOG_INFO, + "[REQUEST] Locker = {%s} Lockee = {%s} Lock = {%s}", pl_locker, + pl_lockee, pl_entrylk); +} + +void +entrylk_trace_out(xlator_t *this, call_frame_t *frame, const char *domain, + fd_t *fd, loc_t *loc, const char *basename, entrylk_cmd cmd, + entrylk_type type, int op_ret, int op_errno) +{ + posix_locks_private_t *priv = NULL; + char pl_locker[256]; + char pl_lockee[256]; + char pl_entrylk[256]; + char verdict[32]; + + priv = this->private; + + if (!priv->trace) + return; + + pl_print_locker(pl_locker, 256, this, frame); + pl_print_lockee(pl_lockee, 256, fd, loc); + pl_print_entrylk(pl_entrylk, 256, cmd, type, basename, domain); + pl_print_verdict(verdict, 32, op_ret, op_errno); + + gf_log(this->name, GF_LOG_INFO, + "[%s] Locker = {%s} Lockee = {%s} Lock = {%s}", verdict, pl_locker, + pl_lockee, pl_entrylk); +} + +void +entrylk_trace_block(xlator_t *this, call_frame_t *frame, const char *volume, + fd_t *fd, loc_t *loc, const char *basename, entrylk_cmd cmd, + entrylk_type type) + +{ + posix_locks_private_t *priv = NULL; + char pl_locker[256]; + char pl_lockee[256]; + char pl_entrylk[256]; + + priv = this->private; + + if (!priv->trace) + return; + + pl_print_locker(pl_locker, 256, this, frame); + pl_print_lockee(pl_lockee, 256, fd, loc); + pl_print_entrylk(pl_entrylk, 256, cmd, type, basename, volume); + + gf_log(this->name, GF_LOG_INFO, + "[BLOCKED] Locker = {%s} Lockee = {%s} Lock = {%s}", pl_locker, + pl_lockee, pl_entrylk); +} + +/** + * __find_most_matching_lock - find the lock struct which most matches in order + * of: lock on the exact basename || an all_names lock + * + * + * @inode: inode in which to look + * @basename: name to search for + */ + +static pl_entry_lock_t * +__find_most_matching_lock(pl_dom_list_t *dom, const char *basename) +{ + pl_entry_lock_t *lock; + pl_entry_lock_t *all = NULL; + pl_entry_lock_t *exact = NULL; + + if (list_empty(&dom->entrylk_list)) + return NULL; + + list_for_each_entry(lock, &dom->entrylk_list, domain_list) + { + if (all_names(lock->basename)) + all = lock; + else if (names_equal(lock->basename, basename)) + exact = lock; + } + + return (exact ? exact : all); +} + +static pl_entry_lock_t * +__find_matching_lock(pl_dom_list_t *dom, pl_entry_lock_t *lock) +{ + pl_entry_lock_t *tmp = NULL; + + list_for_each_entry(tmp, &dom->entrylk_list, domain_list) + { + if (names_equal(lock->basename, tmp->basename) && + __same_entrylk_owner(lock, tmp) && (lock->type == tmp->type)) + return tmp; + } + return NULL; +} + +static int +__lock_blocked_add(xlator_t *this, pl_inode_t *pinode, pl_dom_list_t *dom, + pl_entry_lock_t *lock, int nonblock) +{ + if (nonblock) + goto out; + + lock->blkd_time = gf_time(); + list_add_tail(&lock->blocked_locks, &dom->blocked_entrylks); + + gf_msg_trace(this->name, 0, "Blocking lock: {pinode=%p, basename=%s}", + pinode, lock->basename); + + entrylk_trace_block(this, lock->frame, NULL, NULL, NULL, lock->basename, + ENTRYLK_LOCK, lock->type); +out: + return -EAGAIN; +} + +/** + * __lock_entrylk - lock a name in a directory + * @inode: inode for the directory in which to lock + * @basename: name of the entry to lock + * if null, lock the entire directory + * + * the entire directory being locked is represented as: a single + * pl_entry_lock_t present in the entrylk_locks list with its + * basename = NULL + */ + +int +__lock_entrylk(xlator_t *this, pl_inode_t *pinode, pl_entry_lock_t *lock, + int nonblock, pl_dom_list_t *dom, struct timespec *now, + struct list_head *contend) +{ + pl_entry_lock_t *conf = NULL; + int ret = -EAGAIN; + + conf = __entrylk_grantable(this, dom, lock, now, contend); + if (conf) { + ret = __lock_blocked_add(this, pinode, dom, lock, nonblock); + goto out; + } + + /* To prevent blocked locks starvation, check if there are any blocked + * locks thay may conflict with this lock. If there is then don't grant + * the lock. BUT grant the lock if the owner already has lock to allow + * nested locks. + * Example: SHD from Machine1 takes (gfid, basename=257-length-name) + * and is granted. + * SHD from machine2 takes (gfid, basename=NULL) and is blocked. + * When SHD from Machine1 takes (gfid, basename=NULL) it needs to be + * granted, without which self-heal can't progress. + * TODO: Find why 'owner_has_lock' is checked even for blocked locks. + */ + if (__blocked_entrylk_conflict(dom, lock) && + !(__owner_has_lock(dom, lock))) { + if (nonblock == 0) { + gf_log(this->name, GF_LOG_DEBUG, + "Lock is grantable, but blocking to prevent " + "starvation"); + } + + ret = __lock_blocked_add(this, pinode, dom, lock, nonblock); + goto out; + } + + __pl_entrylk_ref(lock); + lock->granted_time = gf_time(); + list_add(&lock->domain_list, &dom->entrylk_list); + + ret = 0; +out: + return ret; +} + +/** + * __unlock_entrylk - unlock a name in a directory + * @inode: inode for the directory to unlock in + * @basename: name of the entry to unlock + * if null, unlock the entire directory + */ + +pl_entry_lock_t * +__unlock_entrylk(pl_dom_list_t *dom, pl_entry_lock_t *lock) +{ + pl_entry_lock_t *ret_lock = NULL; + + ret_lock = __find_matching_lock(dom, lock); + + if (ret_lock) { + list_del_init(&ret_lock->domain_list); + } else { + gf_log("locks", GF_LOG_ERROR, + "unlock on %s " + "(type=ENTRYLK_WRLCK) attempted but no matching lock " + "found", + lock->basename); + } + + return ret_lock; +} + +int32_t +check_entrylk_on_basename(xlator_t *this, inode_t *parent, char *basename) +{ + int32_t entrylk = 0; + pl_dom_list_t *dom = NULL; + pl_entry_lock_t *conf = NULL; + + pl_inode_t *pinode = pl_inode_get(this, parent, NULL); + if (!pinode) + goto out; + pthread_mutex_lock(&pinode->mutex); + { + list_for_each_entry(dom, &pinode->dom_list, inode_list) + { + conf = __find_most_matching_lock(dom, basename); + if (conf && conf->basename) { + entrylk = 1; + break; + } + } + } + pthread_mutex_unlock(&pinode->mutex); + +out: + return entrylk; +} + +void +__grant_blocked_entry_locks(xlator_t *this, pl_inode_t *pl_inode, + pl_dom_list_t *dom, struct list_head *granted, + struct timespec *now, struct list_head *contend) +{ + int bl_ret = 0; + pl_entry_lock_t *bl = NULL; + pl_entry_lock_t *tmp = NULL; + + struct list_head blocked_list; + + INIT_LIST_HEAD(&blocked_list); + list_splice_init(&dom->blocked_entrylks, &blocked_list); + + list_for_each_entry_safe(bl, tmp, &blocked_list, blocked_locks) + { + list_del_init(&bl->blocked_locks); + + bl_ret = __lock_entrylk(bl->this, pl_inode, bl, 0, dom, now, contend); + + if (bl_ret == 0) { + list_add_tail(&bl->blocked_locks, granted); + } + } +} + +/* Grants locks if possible which are blocked on a lock */ +void +grant_blocked_entry_locks(xlator_t *this, pl_inode_t *pl_inode, + pl_dom_list_t *dom, struct timespec *now, + struct list_head *contend) +{ + struct list_head granted_list; + pl_entry_lock_t *tmp = NULL; + pl_entry_lock_t *lock = NULL; + + INIT_LIST_HEAD(&granted_list); + + pthread_mutex_lock(&pl_inode->mutex); + { + __grant_blocked_entry_locks(this, pl_inode, dom, &granted_list, now, + contend); + } + pthread_mutex_unlock(&pl_inode->mutex); + + list_for_each_entry_safe(lock, tmp, &granted_list, blocked_locks) + { + entrylk_trace_out(this, lock->frame, NULL, NULL, NULL, lock->basename, + ENTRYLK_LOCK, lock->type, 0, 0); + + STACK_UNWIND_STRICT(entrylk, lock->frame, 0, 0, NULL); + lock->frame = NULL; + } + + pthread_mutex_lock(&pl_inode->mutex); + { + list_for_each_entry_safe(lock, tmp, &granted_list, blocked_locks) + { + list_del_init(&lock->blocked_locks); + __pl_entrylk_unref(lock); + } + } + pthread_mutex_unlock(&pl_inode->mutex); +} + +/* Common entrylk code called by pl_entrylk and pl_fentrylk */ +int +pl_common_entrylk(call_frame_t *frame, xlator_t *this, const char *volume, + inode_t *inode, const char *basename, entrylk_cmd cmd, + entrylk_type type, loc_t *loc, fd_t *fd, dict_t *xdata) + +{ + int32_t op_ret = -1; + int32_t op_errno = 0; + int ret = -1; + char unwind = 1; + GF_UNUSED int dict_ret = -1; + pl_inode_t *pinode = NULL; + pl_entry_lock_t *reqlock = NULL; + pl_entry_lock_t *unlocked = NULL; + pl_dom_list_t *dom = NULL; + char *conn_id = NULL; + pl_ctx_t *ctx = NULL; + int nonblock = 0; + gf_boolean_t need_inode_unref = _gf_false; + posix_locks_private_t *priv = NULL; + struct list_head *pcontend = NULL; + struct list_head contend; + struct timespec now = {}; + + priv = this->private; + + if (priv->notify_contention) { + pcontend = &contend; + INIT_LIST_HEAD(pcontend); + timespec_now(&now); + } + + if (xdata) + dict_ret = dict_get_str(xdata, "connection-id", &conn_id); + + pinode = pl_inode_get(this, inode, NULL); + if (!pinode) { + op_errno = ENOMEM; + goto out; + } + + if (frame->root->client) { + ctx = pl_ctx_get(frame->root->client, this); + if (!ctx) { + op_errno = ENOMEM; + gf_log(this->name, GF_LOG_INFO, "pl_ctx_get() failed"); + goto unwind; + } + } + + dom = get_domain(pinode, volume); + if (!dom) { + op_errno = ENOMEM; + goto out; + } + + entrylk_trace_in(this, frame, volume, fd, loc, basename, cmd, type); + + reqlock = new_entrylk_lock(pinode, basename, type, dom->domain, frame, + conn_id, &op_errno); + if (!reqlock) { + op_ret = -1; + goto unwind; + } + + /* Ideally, AFTER a successful lock (both blocking and non-blocking) or + * an unsuccessful blocking lock operation, the inode needs to be ref'd. + * + * But doing so might give room to a race where the lock-requesting + * client could send a DISCONNECT just before this thread refs the inode + * after the locking is done, and the epoll thread could unref the inode + * in cleanup which means the inode's refcount would come down to 0, and + * the call to pl_forget() at this point destroys @pinode. Now when + * the io-thread executing this function tries to access pinode, + * it could crash on account of illegal memory access. + * + * To get around this problem, the inode is ref'd once even before + * adding the lock into client_list as a precautionary measure. + * This way even if there are DISCONNECTs, there will always be 1 extra + * ref on the inode, so @pinode is still alive until after the + * current stack unwinds. + */ + pinode->inode = inode_ref(inode); + if (priv->revocation_secs != 0) { + if (cmd != ENTRYLK_UNLOCK) { + __entrylk_prune_stale(this, pinode, dom, reqlock); + } else if (priv->monkey_unlocking == _gf_true) { + if (pl_does_monkey_want_stuck_lock()) { + gf_log(this->name, GF_LOG_WARNING, + "MONKEY LOCKING (forcing stuck lock)!"); + op_ret = 0; + need_inode_unref = _gf_true; + pthread_mutex_lock(&pinode->mutex); + { + __pl_entrylk_unref(reqlock); + } + pthread_mutex_unlock(&pinode->mutex); + goto out; + } + } + } + + switch (cmd) { + case ENTRYLK_LOCK_NB: + nonblock = 1; + /* fall through */ + case ENTRYLK_LOCK: + if (ctx) + pthread_mutex_lock(&ctx->lock); + pthread_mutex_lock(&pinode->mutex); + { + reqlock->pinode = pinode; + + ret = __lock_entrylk(this, pinode, reqlock, nonblock, dom, &now, + pcontend); + if (ret == 0) { + reqlock->frame = NULL; + op_ret = 0; + } else { + op_errno = -ret; + } + + if (ctx && (!ret || !nonblock)) + list_add(&reqlock->client_list, &ctx->entrylk_lockers); + + if (ret == -EAGAIN && !nonblock) { + /* blocked */ + unwind = 0; + } else { + __pl_entrylk_unref(reqlock); + } + + /* For all but the case where a non-blocking lock + * attempt fails, the extra ref taken before the switch + * block must be negated. + */ + if ((ret == -EAGAIN) && (nonblock)) + need_inode_unref = _gf_true; + } + pthread_mutex_unlock(&pinode->mutex); + if (ctx) + pthread_mutex_unlock(&ctx->lock); + break; + + case ENTRYLK_UNLOCK: + if (ctx) + pthread_mutex_lock(&ctx->lock); + pthread_mutex_lock(&pinode->mutex); + { + /* Irrespective of whether unlock succeeds or not, + * the extra inode ref that was done before the switch + * block must be negated. Towards this, + * @need_inode_unref flag is set unconditionally here. + */ + need_inode_unref = _gf_true; + unlocked = __unlock_entrylk(dom, reqlock); + if (unlocked) { + list_del_init(&unlocked->client_list); + __pl_entrylk_unref(unlocked); + op_ret = 0; + } else { + op_errno = EINVAL; + } + __pl_entrylk_unref(reqlock); + } + pthread_mutex_unlock(&pinode->mutex); + if (ctx) + pthread_mutex_unlock(&ctx->lock); + + grant_blocked_entry_locks(this, pinode, dom, &now, pcontend); + + break; + + default: + need_inode_unref = _gf_true; + gf_log(this->name, GF_LOG_ERROR, + "Unexpected case in entrylk (cmd=%d). Please file" + "a bug report at http://bugs.gluster.com", + cmd); + goto out; + } + /* The following (extra) unref corresponds to the ref that + * was done at the time the lock was granted. + */ + if ((cmd == ENTRYLK_UNLOCK) && (op_ret == 0)) + inode_unref(pinode->inode); + +out: + + if (need_inode_unref) + inode_unref(pinode->inode); + + if (unwind) { + entrylk_trace_out(this, frame, volume, fd, loc, basename, cmd, type, + op_ret, op_errno); + unwind: + STACK_UNWIND_STRICT(entrylk, frame, op_ret, op_errno, NULL); + } + + if (pcontend != NULL) { + entrylk_contention_notify(this, pcontend); + } + + return 0; +} + +/** + * pl_entrylk: + * + * Locking on names (directory entries) + */ + +int +pl_entrylk(call_frame_t *frame, xlator_t *this, const char *volume, loc_t *loc, + const char *basename, entrylk_cmd cmd, entrylk_type type, + dict_t *xdata) +{ + pl_common_entrylk(frame, this, volume, loc->inode, basename, cmd, type, loc, + NULL, xdata); + + return 0; +} + +/** + * pl_fentrylk: + * + * Locking on names (directory entries) + */ + +int +pl_fentrylk(call_frame_t *frame, xlator_t *this, const char *volume, fd_t *fd, + const char *basename, entrylk_cmd cmd, entrylk_type type, + dict_t *xdata) +{ + pl_common_entrylk(frame, this, volume, fd->inode, basename, cmd, type, NULL, + fd, xdata); + + return 0; +} + +static void +pl_entrylk_log_cleanup(pl_entry_lock_t *lock) +{ + pl_inode_t *pinode = NULL; + + pinode = lock->pinode; + + gf_log(THIS->name, GF_LOG_WARNING, + "releasing lock on %s held by " + "{client=%p, pid=%" PRId64 " lk-owner=%s}", + uuid_utoa(pinode->gfid), lock->client, (uint64_t)lock->client_pid, + lkowner_utoa(&lock->owner)); +} + +/* Release all entrylks from this client */ +int +pl_entrylk_client_cleanup(xlator_t *this, pl_ctx_t *ctx) +{ + posix_locks_private_t *priv; + pl_entry_lock_t *tmp = NULL; + pl_entry_lock_t *l = NULL; + pl_dom_list_t *dom = NULL; + pl_inode_t *pinode = NULL; + struct list_head *pcontend = NULL; + struct list_head released; + struct list_head unwind; + struct list_head contend; + struct timespec now = {}; + + INIT_LIST_HEAD(&released); + INIT_LIST_HEAD(&unwind); + + priv = this->private; + if (priv->notify_contention) { + pcontend = &contend; + INIT_LIST_HEAD(pcontend); + timespec_now(&now); + } + + pthread_mutex_lock(&ctx->lock); + { + list_for_each_entry_safe(l, tmp, &ctx->entrylk_lockers, client_list) + { + pl_entrylk_log_cleanup(l); + + pinode = l->pinode; + + pthread_mutex_lock(&pinode->mutex); + { + /* If the entrylk object is part of granted list but not + * blocked list, then perform the following actions: + * i. delete the object from granted list; + * ii. grant other locks (from other clients) that may + * have been blocked on this entrylk; and + * iii. unref the object. + * + * If the entrylk object (L1) is part of both granted + * and blocked lists, then this means that a parallel + * unlock on another entrylk (L2 say) may have 'granted' + * L1 and added it to 'granted' list in + * __grant_blocked_entry_locks() (although using the + * 'blocked_locks' member). In that case, the cleanup + * codepath must try and grant other overlapping + * blocked entrylks from other clients, now that L1 is + * out of their way and then unref L1 in the end, and + * leave it to the other thread (the one executing + * unlock codepath) to unwind L1's frame, delete it from + * blocked_locks list, and perform the last unref on L1. + * + * If the entrylk object (L1) is part of blocked list + * only, the cleanup code path must: + * i. delete it from the blocked_locks list inside + * this critical section, + * ii. unwind its frame with EAGAIN, + * iii. try and grant blocked entry locks from other + * clients that were otherwise grantable, but were + * blocked to avoid leaving L1 to starve forever. + * iv. unref the object. + */ + list_del_init(&l->client_list); + + if (!list_empty(&l->domain_list)) { + list_del_init(&l->domain_list); + list_add_tail(&l->client_list, &released); + } else { + list_del_init(&l->blocked_locks); + list_add_tail(&l->client_list, &unwind); + } + } + pthread_mutex_unlock(&pinode->mutex); + } + } + pthread_mutex_unlock(&ctx->lock); + + if (!list_empty(&unwind)) { + list_for_each_entry_safe(l, tmp, &unwind, client_list) + { + list_del_init(&l->client_list); + + if (l->frame) + STACK_UNWIND_STRICT(entrylk, l->frame, -1, EAGAIN, NULL); + list_add_tail(&l->client_list, &released); + } + } + + if (!list_empty(&released)) { + list_for_each_entry_safe(l, tmp, &released, client_list) + { + list_del_init(&l->client_list); + + pinode = l->pinode; + + dom = get_domain(pinode, l->volume); + + grant_blocked_entry_locks(this, pinode, dom, &now, pcontend); + + pthread_mutex_lock(&pinode->mutex); + { + __pl_entrylk_unref(l); + } + pthread_mutex_unlock(&pinode->mutex); + + inode_unref(pinode->inode); + } + } + + if (pcontend != NULL) { + entrylk_contention_notify(this, pcontend); + } + + return 0; +} + +int32_t +__get_entrylk_count(xlator_t *this, pl_inode_t *pl_inode) +{ + int32_t count = 0; + pl_entry_lock_t *lock = NULL; + pl_dom_list_t *dom = NULL; + + list_for_each_entry(dom, &pl_inode->dom_list, inode_list) + { + list_for_each_entry(lock, &dom->entrylk_list, domain_list) { count++; } + + list_for_each_entry(lock, &dom->blocked_entrylks, blocked_locks) + { + count++; + } + } + + return count; +} + +int32_t +get_entrylk_count(xlator_t *this, inode_t *inode) +{ + pl_inode_t *pl_inode = NULL; + uint64_t tmp_pl_inode = 0; + int ret = 0; + int32_t count = 0; + + ret = inode_ctx_get(inode, this, &tmp_pl_inode); + if (ret != 0) { + goto out; + } + + pl_inode = (pl_inode_t *)(long)tmp_pl_inode; + + pthread_mutex_lock(&pl_inode->mutex); + { + count = __get_entrylk_count(this, pl_inode); + } + pthread_mutex_unlock(&pl_inode->mutex); + +out: + return count; +} |