lustre/ldlm/ldlm_lock.c

   1 /* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
   2  * vim:expandtab:shiftwidth=8:tabstop=8:
   3  *
   4  * Copyright (C) 2002 Cluster File Systems, Inc.
   5  *
   6  * This code is issued under the GNU General Public License.
   7  * See the file COPYING in this distribution
   8  *
   9  * by Cluster File Systems, Inc.
  10  * authors, Peter Braam <braam@clusterfs.com> &
  11  * Phil Schwan <phil@clusterfs.com>
  12  */
  13
  14 #define EXPORT_SYMTAB
  15
  16 #include <linux/version.h>
  17 #include <linux/module.h>
  18 #include <linux/slab.h>
  19 #include <asm/unistd.h>
  20
  21 #define DEBUG_SUBSYSTEM S_LDLM
  22
  23 #include <linux/obd_support.h>
  24 #include <linux/obd_class.h>
  25
  26 #include <linux/lustre_dlm.h>
  27
  28 extern kmem_cache_t *ldlm_lock_slab;
  29
  30 static int ldlm_plain_compat(struct ldlm_lock *a, struct ldlm_lock *b);
  31 static int ldlm_intent_compat(struct ldlm_lock *a, struct ldlm_lock *b);
  32
  33 ldlm_res_compat ldlm_res_compat_table [] = {
  34         [LDLM_PLAIN] ldlm_plain_compat,
  35         [LDLM_EXTENT] ldlm_extent_compat,
  36         [LDLM_MDSINTENT] ldlm_intent_compat
  37 };
  38
  39 ldlm_res_policy ldlm_res_policy_table [] = {
  40         [LDLM_PLAIN] NULL,
  41         [LDLM_EXTENT] ldlm_extent_policy,
  42         [LDLM_MDSINTENT] NULL
  43 };
  44
  45 static int ldlm_plain_compat(struct ldlm_lock *a, struct ldlm_lock *b)
  46 {
  47         return lockmode_compat(a->l_req_mode, b->l_req_mode);
  48 }
  49
  50 static int ldlm_intent_compat(struct ldlm_lock *a, struct ldlm_lock *b)
  51 {
  52         LBUG();
  53         return 0;
  54 }
  55
  56 static struct ldlm_lock *ldlm_lock_new(struct ldlm_lock *parent,
  57                                        struct ldlm_resource *resource)
  58 {
  59         struct ldlm_lock *lock;
  60
  61         if (resource == NULL)
  62                 LBUG();
  63
  64         lock = kmem_cache_alloc(ldlm_lock_slab, SLAB_KERNEL);
  65         if (lock == NULL)
  66                 return NULL;
  67
  68         memset(lock, 0, sizeof(*lock));
  69         lock->l_resource = resource;
  70         INIT_LIST_HEAD(&lock->l_children);
  71
  72         if (parent != NULL) {
  73                 lock->l_parent = parent;
  74                 list_add(&lock->l_childof, &parent->l_children);
  75         }
  76
  77         return lock;
  78 }
  79
  80 void ldlm_lock_free(struct ldlm_lock *lock)
  81 {
  82         kmem_cache_free(ldlm_lock_slab, lock);
  83 }
  84
  85 void ldlm_lock2desc(struct ldlm_lock *lock, struct ldlm_lock_desc *desc)
  86 {
  87         ldlm_res2desc(lock->l_resource, &desc->l_resource);
  88         desc->l_req_mode = lock->l_req_mode;
  89         desc->l_granted_mode = lock->l_granted_mode;
  90         memcpy(&desc->l_extent, &lock->l_extent, sizeof(desc->l_extent));
  91         memcpy(desc->l_version, lock->l_version, sizeof(desc->l_version));
  92 }
  93
  94 static int ldlm_lock_compat(struct ldlm_lock *lock)
  95 {
  96         struct list_head *tmp;
  97         int rc = 0;
  98
  99         list_for_each(tmp, &lock->l_resource->lr_granted) {
 100                 struct ldlm_lock *child;
 101                 ldlm_res_compat compat;
 102
 103                 child = list_entry(tmp, struct ldlm_lock, l_res_link);
 104
 105                 compat = ldlm_res_compat_table[child->l_resource->lr_type];
 106                 if (compat(child, lock) ||
 107                     lockmode_compat(child->l_req_mode, lock->l_req_mode))
 108                         continue;
 109
 110                 rc = 1;
 111
 112                 if (child->l_blocking_ast != NULL)
 113                         child->l_blocking_ast(child, lock, child->l_data,
 114                                               child->l_data_len);
 115         }
 116
 117         return rc;
 118 }
 119
 120 static void ldlm_grant_lock(struct ldlm_resource *res, struct ldlm_lock *lock)
 121 {
 122         ldlm_resource_add_lock(res, &res->lr_granted, lock);
 123         lock->l_granted_mode = lock->l_req_mode;
 124
 125         if (lock->l_granted_mode < res->lr_most_restr)
 126                 res->lr_most_restr = lock->l_granted_mode;
 127
 128         if (lock->l_completion_ast)
 129                 lock->l_completion_ast(lock, NULL,
 130                                        lock->l_data, lock->l_data_len);
 131 }
 132
 133 ldlm_error_t ldlm_local_lock_create(__u32 ns_id,
 134                                     struct ldlm_handle *parent_lock_handle,
 135                                     __u64 *res_id,
 136                                     __u32 type,
 137                                     struct ldlm_handle *lockh)
 138 {
 139         struct ldlm_namespace *ns;
 140         struct ldlm_resource *res, *parent_res = NULL;
 141         struct ldlm_lock *lock, *parent_lock;
 142
 143         ns = ldlm_namespace_find(ns_id);
 144         if (ns == NULL || ns->ns_hash == NULL)
 145                 RETURN(-ELDLM_BAD_NAMESPACE);
 146
 147         parent_lock = ldlm_handle2object(parent_lock_handle);
 148         if (parent_lock)
 149                 parent_res = parent_lock->l_resource;
 150
 151         res = ldlm_resource_get(ns, parent_res, res_id, type, 1);
 152         if (res == NULL)
 153                 RETURN(-ENOMEM);
 154
 155         lock = ldlm_lock_new(parent_lock, res);
 156         if (lock == NULL)
 157                 RETURN(-ENOMEM);
 158
 159         ldlm_object2handle(lock, lockh);
 160
 161         return ELDLM_OK;
 162 }
 163
 164 /* XXX: Revisit the error handling; we do not, for example, do
 165  * ldlm_resource_put()s in our error cases, and we probably leak any allocated
 166  * memory. */
 167 ldlm_error_t ldlm_local_lock_enqueue(struct ldlm_handle *lockh,
 168                                      ldlm_mode_t mode,
 169                                      struct ldlm_extent *req_ex,
 170                                      int *flags,
 171                                      ldlm_lock_callback completion,
 172                                      ldlm_lock_callback blocking,
 173                                      void *data,
 174                                      __u32 data_len)
 175 {
 176         struct ldlm_lock *lock;
 177         struct ldlm_extent new_ex;
 178         int incompat = 0, rc;
 179         ldlm_res_policy policy;
 180         ENTRY;
 181
 182         lock = ldlm_handle2object(lockh);
 183         if ((policy = ldlm_res_policy_table[lock->l_resource->lr_type])) {
 184                 rc = policy(lock->l_resource, req_ex, &new_ex, mode, NULL);
 185                 if (rc == ELDLM_LOCK_CHANGED) {
 186                         *flags |= LDLM_FL_LOCK_CHANGED;
 187                         memcpy(req_ex, &new_ex, sizeof(new_ex));
 188                 }
 189         }
 190
 191         if ((lock->l_resource->lr_type == LDLM_EXTENT && !req_ex) ||
 192             (lock->l_resource->lr_type != LDLM_EXTENT && req_ex))
 193                 LBUG();
 194         if (req_ex)
 195                 memcpy(&lock->l_extent, req_ex, sizeof(*req_ex));
 196         lock->l_req_mode = mode;
 197         lock->l_data = data;
 198         lock->l_data_len = data_len;
 199         lock->l_completion_ast = completion;
 200         lock->l_blocking_ast = blocking;
 201         spin_lock(&lock->l_resource->lr_lock);
 202
 203         /* FIXME: We may want to optimize by checking lr_most_restr */
 204
 205         if (!list_empty(&lock->l_resource->lr_converting)) {
 206                 ldlm_resource_add_lock(lock->l_resource,
 207                                        lock->l_resource->lr_waiting.prev, lock);
 208                 *flags |= LDLM_FL_BLOCK_CONV;
 209                 GOTO(out, ELDLM_OK);
 210         }
 211         if (!list_empty(&lock->l_resource->lr_waiting)) {
 212                 ldlm_resource_add_lock(lock->l_resource,
 213                                        lock->l_resource->lr_waiting.prev, lock);
 214                 *flags |= LDLM_FL_BLOCK_WAIT;
 215                 GOTO(out, ELDLM_OK);
 216         }
 217
 218         incompat = ldlm_lock_compat(lock);
 219         if (incompat) {
 220                 ldlm_resource_add_lock(lock->l_resource,
 221                                        lock->l_resource->lr_waiting.prev, lock);
 222                 *flags |= LDLM_FL_BLOCK_GRANTED;
 223                 GOTO(out, ELDLM_OK);
 224         }
 225
 226         ldlm_grant_lock(lock->l_resource, lock);
 227         EXIT;
 228  out:
 229         spin_unlock(&lock->l_resource->lr_lock);
 230         return ELDLM_OK;
 231 }
 232
 233 static int ldlm_reprocess_queue(struct ldlm_resource *res,
 234                                 struct list_head *converting)
 235 {
 236         struct list_head *tmp, *pos;
 237         int incompat = 0;
 238
 239         list_for_each_safe(tmp, pos, converting) {
 240                 struct ldlm_lock *pending;
 241                 pending = list_entry(tmp, struct ldlm_lock, l_res_link);
 242
 243                 incompat = ldlm_lock_compat(pending);
 244                 if (incompat)
 245                         break;
 246
 247                 list_del(&pending->l_res_link);
 248                 ldlm_grant_lock(res, pending);
 249         }
 250
 251         return incompat;
 252 }
 253
 254 static void ldlm_reprocess_all(struct ldlm_resource *res)
 255 {
 256         ldlm_reprocess_queue(res, &res->lr_converting);
 257         if (list_empty(&res->lr_converting))
 258                 ldlm_reprocess_queue(res, &res->lr_waiting);
 259 }
 260
 261 ldlm_error_t ldlm_local_lock_cancel(struct ldlm_handle *lockh)
 262 {
 263         struct ldlm_lock *lock;
 264         struct ldlm_resource *res;
 265         ENTRY;
 266
 267         lock = ldlm_handle2object(lockh);
 268         res = lock->l_resource;
 269
 270         ldlm_resource_del_lock(lock);
 271
 272         ldlm_lock_free(lock);
 273         if (ldlm_resource_put(res))
 274                 RETURN(ELDLM_OK);
 275         ldlm_reprocess_all(res);
 276
 277         RETURN(ELDLM_OK);
 278 }
 279
 280 ldlm_error_t ldlm_local_lock_convert(struct ldlm_handle *lockh,
 281                                      int new_mode, int *flags)
 282 {
 283         struct ldlm_lock *lock;
 284         struct ldlm_resource *res;
 285         ENTRY;
 286
 287         lock = ldlm_handle2object(lockh);
 288         res = lock->l_resource;
 289         list_del(&lock->l_res_link);
 290         lock->l_req_mode = new_mode;
 291
 292         list_add(&lock->l_res_link, res->lr_converting.prev);
 293
 294         ldlm_reprocess_all(res);
 295
 296         RETURN(ELDLM_OK);
 297 }
 298
 299 void ldlm_lock_dump(struct ldlm_lock *lock)
 300 {
 301         char ver[128];
 302
 303         if (RES_VERSION_SIZE != 4)
 304                 LBUG();
 305
 306         snprintf(ver, sizeof(ver), "%x %x %x %x",
 307                  lock->l_version[0], lock->l_version[1],
 308                  lock->l_version[2], lock->l_version[3]);
 309
 310         CDEBUG(D_OTHER, "  -- Lock dump: %p (%s)\n", lock, ver);
 311         CDEBUG(D_OTHER, "  Parent: %p\n", lock->l_parent);
 312         CDEBUG(D_OTHER, "  Resource: %p\n", lock->l_resource);
 313         CDEBUG(D_OTHER, "  Requested mode: %d, granted mode: %d\n",
 314                (int)lock->l_req_mode, (int)lock->l_granted_mode);
 315         if (lock->l_resource->lr_type == LDLM_EXTENT)
 316                 CDEBUG(D_OTHER, "  Extent: %Lu -> %Lu\n",
 317                        lock->l_extent.start, lock->l_extent.end);
 318 }