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29 * This file is part of Lustre, http://www.lustre.org/
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32 * lustre/ldlm/ldlm_inodebits.c
34 * Author: Peter Braam <braam@clusterfs.com>
35 * Author: Phil Schwan <phil@clusterfs.com>
39 * This file contains implementation of IBITS lock type
41 * IBITS lock type contains a bit mask determining various properties of an
42 * object. The meanings of specific bits are specific to the caller and are
43 * opaque to LDLM code.
45 * Locks with intersecting bitmasks and conflicting lock modes (e.g. LCK_PW)
46 * are considered conflicting. See the lock mode compatibility matrix
50 #define DEBUG_SUBSYSTEM S_LDLM
52 #include <lustre_dlm.h>
53 #include <obd_support.h>
54 #include <lustre_lib.h>
55 #include <obd_class.h>
57 #include "ldlm_internal.h"
59 #ifdef HAVE_SERVER_SUPPORT
61 * Determine if the lock is compatible with all locks on the queue.
63 * If \a work_list is provided, conflicting locks are linked there.
64 * If \a work_list is not provided, we exit this function on first conflict.
66 * \retval 0 if there are conflicting locks in the \a queue
67 * \retval 1 if the lock is compatible to all locks in \a queue
69 * IBITS locks in granted queue are organized in bunches of
70 * same-mode/same-bits locks called "skip lists". The First lock in the
71 * bunch contains a pointer to the end of the bunch. This allows us to
72 * skip an entire bunch when iterating the list in search for conflicting
73 * locks if first lock of the bunch is not conflicting with us.
76 ldlm_inodebits_compat_queue(struct list_head *queue, struct ldlm_lock *req,
77 struct list_head *work_list)
79 struct list_head *tmp;
80 struct ldlm_lock *lock;
81 __u64 req_bits = req->l_policy_data.l_inodebits.bits;
82 __u64 *try_bits = &req->l_policy_data.l_inodebits.try_bits;
87 /* There is no sense in lock with no bits set. Also such a lock
88 * would be compatible with any other bit lock.
89 * Meanwhile that can be true if there were just try_bits and all
90 * are failed, so just exit gracefully and let the caller to care.
92 if ((req_bits | *try_bits) == 0)
95 list_for_each(tmp, queue) {
96 struct list_head *mode_tail;
98 lock = list_entry(tmp, struct ldlm_lock, l_res_link);
100 /* We stop walking the queue if we hit ourselves so we don't
101 * take conflicting locks enqueued after us into account,
102 * or we'd wait forever. */
106 /* last lock in mode group */
107 LASSERT(lock->l_sl_mode.prev != NULL);
108 mode_tail = &list_entry(lock->l_sl_mode.prev, struct ldlm_lock,
109 l_sl_mode)->l_res_link;
111 /* if request lock is not COS_INCOMPAT and COS is disabled,
112 * they are compatible, IOW this request is from a local
113 * transaction on a DNE system. */
114 if (lock->l_req_mode == LCK_COS && !ldlm_is_cos_incompat(req) &&
115 !ldlm_is_cos_enabled(req)) {
116 /* jump to last lock in mode group */
121 /* locks' mode are compatible, bits don't matter */
122 if (lockmode_compat(lock->l_req_mode, req->l_req_mode)) {
123 /* jump to last lock in mode group */
129 struct list_head *head;
131 /* Advance loop cursor to last lock in policy group. */
132 tmp = &list_entry(lock->l_sl_policy.prev,
134 l_sl_policy)->l_res_link;
136 /* drop try_bits used by other locks */
137 *try_bits &= ~(lock->l_policy_data.l_inodebits.bits);
138 if ((req_bits | *try_bits) == 0)
141 /* Locks with overlapping bits conflict. */
142 if (lock->l_policy_data.l_inodebits.bits & req_bits) {
143 /* COS lock mode has a special compatibility
144 * requirement: it is only compatible with
145 * locks from the same client. */
146 if (lock->l_req_mode == LCK_COS &&
147 !ldlm_is_cos_incompat(req) &&
148 ldlm_is_cos_enabled(req) &&
149 lock->l_client_cookie == req->l_client_cookie)
150 goto not_conflicting;
151 /* Found a conflicting policy group. */
157 /* Add locks of the policy group to @work_list
158 * as blocking locks for @req */
159 if (lock->l_blocking_ast)
160 ldlm_add_ast_work_item(lock, req,
162 head = &lock->l_sl_policy;
163 list_for_each_entry(lock, head, l_sl_policy)
164 if (lock->l_blocking_ast)
165 ldlm_add_ast_work_item(lock,
169 if (tmp == mode_tail)
173 lock = list_entry(tmp, struct ldlm_lock, l_res_link);
174 } /* Loop over policy groups within one mode group. */
175 } /* Loop over mode groups within @queue. */
181 * Process a granting attempt for IBITS lock.
182 * Must be called with ns lock held
184 * This function looks for any conflicts for \a lock in the granted or
185 * waiting queues. The lock is granted if no conflicts are found in
188 int ldlm_process_inodebits_lock(struct ldlm_lock *lock, __u64 *flags,
189 enum ldlm_process_intention intention,
190 enum ldlm_error *err,
191 struct list_head *work_list)
193 struct ldlm_resource *res = lock->l_resource;
194 struct list_head rpc_list;
199 LASSERT(lock->l_granted_mode != lock->l_req_mode);
200 LASSERT(list_empty(&res->lr_converting));
201 INIT_LIST_HEAD(&rpc_list);
202 check_res_locked(res);
204 if (intention == LDLM_PROCESS_RESCAN) {
205 *err = ELDLM_LOCK_ABORTED;
207 LASSERT(lock->l_policy_data.l_inodebits.bits != 0);
209 rc = ldlm_inodebits_compat_queue(&res->lr_granted, lock, NULL);
211 RETURN(LDLM_ITER_STOP);
212 rc = ldlm_inodebits_compat_queue(&res->lr_waiting, lock, NULL);
214 RETURN(LDLM_ITER_STOP);
216 /* grant also try_bits if any */
217 if (lock->l_policy_data.l_inodebits.try_bits != 0) {
218 lock->l_policy_data.l_inodebits.bits |=
219 lock->l_policy_data.l_inodebits.try_bits;
220 *flags |= LDLM_FL_LOCK_CHANGED;
222 ldlm_resource_unlink_lock(lock);
223 ldlm_grant_lock(lock, work_list);
226 RETURN(LDLM_ITER_CONTINUE);
229 LASSERT((intention == LDLM_PROCESS_ENQUEUE && work_list == NULL) ||
230 (intention == LDLM_PROCESS_RECOVERY && work_list != NULL));
232 rc = ldlm_inodebits_compat_queue(&res->lr_granted, lock, &rpc_list);
233 rc += ldlm_inodebits_compat_queue(&res->lr_waiting, lock, &rpc_list);
236 /* if there were only bits to try and all are conflicting */
237 if ((lock->l_policy_data.l_inodebits.bits |
238 lock->l_policy_data.l_inodebits.try_bits) == 0) {
239 rc = ELDLM_LOCK_WOULDBLOCK;
241 rc = ldlm_handle_conflict_lock(lock, flags,
248 /* grant also all remaining try_bits */
249 if (lock->l_policy_data.l_inodebits.try_bits != 0) {
250 lock->l_policy_data.l_inodebits.bits |=
251 lock->l_policy_data.l_inodebits.try_bits;
252 *flags |= LDLM_FL_LOCK_CHANGED;
254 LASSERT(lock->l_policy_data.l_inodebits.bits);
255 ldlm_resource_unlink_lock(lock);
256 ldlm_grant_lock(lock, work_list);
260 if (!list_empty(&rpc_list))
261 ldlm_discard_bl_list(&rpc_list);
265 #endif /* HAVE_SERVER_SUPPORT */
267 void ldlm_ibits_policy_wire_to_local(const union ldlm_wire_policy_data *wpolicy,
268 union ldlm_policy_data *lpolicy)
270 lpolicy->l_inodebits.bits = wpolicy->l_inodebits.bits;
271 lpolicy->l_inodebits.try_bits = wpolicy->l_inodebits.try_bits;
274 void ldlm_ibits_policy_local_to_wire(const union ldlm_policy_data *lpolicy,
275 union ldlm_wire_policy_data *wpolicy)
277 memset(wpolicy, 0, sizeof(*wpolicy));
278 wpolicy->l_inodebits.bits = lpolicy->l_inodebits.bits;
279 wpolicy->l_inodebits.try_bits = lpolicy->l_inodebits.try_bits;