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36 * lustre/ldlm/ldlm_inodebits.c
38 * Author: Peter Braam <braam@clusterfs.com>
39 * Author: Phil Schwan <phil@clusterfs.com>
43 * This file contains implementation of IBITS lock type
45 * IBITS lock type contains a bit mask determining various properties of an
46 * object. The meanings of specific bits are specific to the caller and are
47 * opaque to LDLM code.
49 * Locks with intersecting bitmasks and conflicting lock modes (e.g. LCK_PW)
50 * are considered conflicting. See the lock mode compatibility matrix
54 #define DEBUG_SUBSYSTEM S_LDLM
56 #include <lustre_dlm.h>
57 #include <obd_support.h>
58 #include <lustre_lib.h>
60 #include "ldlm_internal.h"
62 #ifdef HAVE_SERVER_SUPPORT
64 * Determine if the lock is compatible with all locks on the queue.
66 * If \a work_list is provided, conflicting locks are linked there.
67 * If \a work_list is not provided, we exit this function on first conflict.
69 * \retval 0 if there are conflicting locks in the \a queue
70 * \retval 1 if the lock is compatible to all locks in \a queue
72 * IBITS locks in granted queue are organized in bunches of
73 * same-mode/same-bits locks called "skip lists". The First lock in the
74 * bunch contains a pointer to the end of the bunch. This allows us to
75 * skip an entire bunch when iterating the list in search for conflicting
76 * locks if first lock of the bunch is not conflicting with us.
79 ldlm_inodebits_compat_queue(struct list_head *queue, struct ldlm_lock *req,
80 struct list_head *work_list)
82 struct list_head *tmp;
83 struct ldlm_lock *lock;
84 enum ldlm_mode req_mode = req->l_req_mode;
85 __u64 req_bits = req->l_policy_data.l_inodebits.bits;
89 /* There is no sense in lock with no bits set, I think.
90 * Also, such a lock would be compatible with any other bit lock */
91 LASSERT(req_bits != 0);
93 list_for_each(tmp, queue) {
94 struct list_head *mode_tail;
96 lock = list_entry(tmp, struct ldlm_lock, l_res_link);
98 /* We stop walking the queue if we hit ourselves so we don't
99 * take conflicting locks enqueued after us into account,
100 * or we'd wait forever. */
104 /* last lock in mode group */
105 LASSERT(lock->l_sl_mode.prev != NULL);
106 mode_tail = &list_entry(lock->l_sl_mode.prev,
108 l_sl_mode)->l_res_link;
110 /* locks are compatible, bits don't matter */
111 if (lockmode_compat(lock->l_req_mode, req_mode)) {
112 /* jump to last lock in mode group */
118 struct list_head *head;
120 /* Advance loop cursor to last lock in policy group. */
121 tmp = &list_entry(lock->l_sl_policy.prev,
123 l_sl_policy)->l_res_link;
125 /* Locks with overlapping bits conflict. */
126 if (lock->l_policy_data.l_inodebits.bits & req_bits) {
127 /* COS lock mode has a special compatibility
128 * requirement: it is only compatible with
129 * locks from the same client. */
130 if (lock->l_req_mode == LCK_COS &&
131 lock->l_client_cookie == req->l_client_cookie)
132 goto not_conflicting;
133 /* Found a conflicting policy group. */
139 /* Add locks of the policy group to @work_list
140 * as blocking locks for @req */
141 if (lock->l_blocking_ast)
142 ldlm_add_ast_work_item(lock, req,
144 head = &lock->l_sl_policy;
145 list_for_each_entry(lock, head, l_sl_policy)
146 if (lock->l_blocking_ast)
147 ldlm_add_ast_work_item(lock, req,
151 if (tmp == mode_tail)
155 lock = list_entry(tmp, struct ldlm_lock,
157 } /* Loop over policy groups within one mode group. */
158 } /* Loop over mode groups within @queue. */
164 * Process a granting attempt for IBITS lock.
165 * Must be called with ns lock held
167 * This function looks for any conflicts for \a lock in the granted or
168 * waiting queues. The lock is granted if no conflicts are found in
171 * If \a first_enq is 0 (ie, called from ldlm_reprocess_queue):
172 * - blocking ASTs have already been sent
174 * If \a first_enq is 1 (ie, called from ldlm_lock_enqueue):
175 * - blocking ASTs have not been sent yet, so list of conflicting locks
176 * would be collected and ASTs sent.
178 int ldlm_process_inodebits_lock(struct ldlm_lock *lock, __u64 *flags,
179 int first_enq, enum ldlm_error *err,
180 struct list_head *work_list)
182 struct ldlm_resource *res = lock->l_resource;
183 struct list_head rpc_list;
187 LASSERT(lock->l_granted_mode != lock->l_req_mode);
188 LASSERT(list_empty(&res->lr_converting));
189 INIT_LIST_HEAD(&rpc_list);
190 check_res_locked(res);
192 /* (*flags & LDLM_FL_BLOCK_NOWAIT) is for layout lock right now. */
193 if (!first_enq || (*flags & LDLM_FL_BLOCK_NOWAIT)) {
194 *err = ELDLM_LOCK_ABORTED;
195 if (*flags & LDLM_FL_BLOCK_NOWAIT)
196 *err = ELDLM_LOCK_WOULDBLOCK;
198 rc = ldlm_inodebits_compat_queue(&res->lr_granted, lock, NULL);
200 RETURN(LDLM_ITER_STOP);
201 rc = ldlm_inodebits_compat_queue(&res->lr_waiting, lock, NULL);
203 RETURN(LDLM_ITER_STOP);
205 ldlm_resource_unlink_lock(lock);
206 ldlm_grant_lock(lock, work_list);
209 RETURN(LDLM_ITER_CONTINUE);
213 rc = ldlm_inodebits_compat_queue(&res->lr_granted, lock, &rpc_list);
214 rc += ldlm_inodebits_compat_queue(&res->lr_waiting, lock, &rpc_list);
217 /* If either of the compat_queue()s returned 0, then we
218 * have ASTs to send and must go onto the waiting list.
220 * bug 2322: we used to unlink and re-add here, which was a
221 * terrible folly -- if we goto restart, we could get
222 * re-ordered! Causes deadlock, because ASTs aren't sent! */
223 if (list_empty(&lock->l_res_link))
224 ldlm_resource_add_lock(res, &res->lr_waiting, lock);
226 rc = ldlm_run_ast_work(ldlm_res_to_ns(res), &rpc_list,
231 *flags |= LDLM_FL_BLOCK_GRANTED;
233 ldlm_resource_unlink_lock(lock);
234 ldlm_grant_lock(lock, NULL);
238 #endif /* HAVE_SERVER_SUPPORT */
240 void ldlm_ibits_policy_wire_to_local(const union ldlm_wire_policy_data *wpolicy,
241 union ldlm_policy_data *lpolicy)
243 memset(lpolicy, 0, sizeof(*lpolicy));
244 lpolicy->l_inodebits.bits = wpolicy->l_inodebits.bits;
247 void ldlm_ibits_policy_local_to_wire(const union ldlm_policy_data *lpolicy,
248 union ldlm_wire_policy_data *wpolicy)
250 memset(wpolicy, 0, sizeof(*wpolicy));
251 wpolicy->l_inodebits.bits = lpolicy->l_inodebits.bits;