David Howells | e8d6c55 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 1 | /* AFS file locking support |
| 2 | * |
| 3 | * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. |
| 4 | * Written by David Howells (dhowells@redhat.com) |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or |
| 7 | * modify it under the terms of the GNU General Public License |
| 8 | * as published by the Free Software Foundation; either version |
| 9 | * 2 of the License, or (at your option) any later version. |
| 10 | */ |
| 11 | |
| 12 | #include <linux/smp_lock.h> |
| 13 | #include "internal.h" |
| 14 | |
| 15 | #define AFS_LOCK_GRANTED 0 |
| 16 | #define AFS_LOCK_PENDING 1 |
| 17 | |
| 18 | static void afs_fl_copy_lock(struct file_lock *new, struct file_lock *fl); |
| 19 | static void afs_fl_release_private(struct file_lock *fl); |
| 20 | |
| 21 | static struct workqueue_struct *afs_lock_manager; |
David Howells | ff8e210 | 2007-07-31 00:38:49 -0700 | [diff] [blame] | 22 | static DEFINE_MUTEX(afs_lock_manager_mutex); |
David Howells | e8d6c55 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 23 | |
| 24 | static struct file_lock_operations afs_lock_ops = { |
| 25 | .fl_copy_lock = afs_fl_copy_lock, |
| 26 | .fl_release_private = afs_fl_release_private, |
| 27 | }; |
| 28 | |
| 29 | /* |
| 30 | * initialise the lock manager thread if it isn't already running |
| 31 | */ |
| 32 | static int afs_init_lock_manager(void) |
| 33 | { |
David Howells | ff8e210 | 2007-07-31 00:38:49 -0700 | [diff] [blame] | 34 | int ret; |
| 35 | |
| 36 | ret = 0; |
David Howells | e8d6c55 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 37 | if (!afs_lock_manager) { |
David Howells | ff8e210 | 2007-07-31 00:38:49 -0700 | [diff] [blame] | 38 | mutex_lock(&afs_lock_manager_mutex); |
| 39 | if (!afs_lock_manager) { |
| 40 | afs_lock_manager = |
| 41 | create_singlethread_workqueue("kafs_lockd"); |
| 42 | if (!afs_lock_manager) |
| 43 | ret = -ENOMEM; |
| 44 | } |
| 45 | mutex_unlock(&afs_lock_manager_mutex); |
David Howells | e8d6c55 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 46 | } |
David Howells | ff8e210 | 2007-07-31 00:38:49 -0700 | [diff] [blame] | 47 | return ret; |
David Howells | e8d6c55 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 48 | } |
| 49 | |
| 50 | /* |
| 51 | * destroy the lock manager thread if it's running |
| 52 | */ |
| 53 | void __exit afs_kill_lock_manager(void) |
| 54 | { |
| 55 | if (afs_lock_manager) |
| 56 | destroy_workqueue(afs_lock_manager); |
| 57 | } |
| 58 | |
| 59 | /* |
| 60 | * if the callback is broken on this vnode, then the lock may now be available |
| 61 | */ |
| 62 | void afs_lock_may_be_available(struct afs_vnode *vnode) |
| 63 | { |
| 64 | _enter("{%x:%u}", vnode->fid.vid, vnode->fid.vnode); |
| 65 | |
| 66 | queue_delayed_work(afs_lock_manager, &vnode->lock_work, 0); |
| 67 | } |
| 68 | |
| 69 | /* |
| 70 | * the lock will time out in 5 minutes unless we extend it, so schedule |
| 71 | * extension in a bit less than that time |
| 72 | */ |
| 73 | static void afs_schedule_lock_extension(struct afs_vnode *vnode) |
| 74 | { |
| 75 | queue_delayed_work(afs_lock_manager, &vnode->lock_work, |
| 76 | AFS_LOCKWAIT * HZ / 2); |
| 77 | } |
| 78 | |
| 79 | /* |
David Howells | ff8e210 | 2007-07-31 00:38:49 -0700 | [diff] [blame] | 80 | * grant one or more locks (readlocks are allowed to jump the queue if the |
| 81 | * first lock in the queue is itself a readlock) |
| 82 | * - the caller must hold the vnode lock |
| 83 | */ |
| 84 | static void afs_grant_locks(struct afs_vnode *vnode, struct file_lock *fl) |
| 85 | { |
| 86 | struct file_lock *p, *_p; |
| 87 | |
| 88 | list_move_tail(&fl->fl_u.afs.link, &vnode->granted_locks); |
| 89 | if (fl->fl_type == F_RDLCK) { |
| 90 | list_for_each_entry_safe(p, _p, &vnode->pending_locks, |
| 91 | fl_u.afs.link) { |
| 92 | if (p->fl_type == F_RDLCK) { |
| 93 | p->fl_u.afs.state = AFS_LOCK_GRANTED; |
| 94 | list_move_tail(&p->fl_u.afs.link, |
| 95 | &vnode->granted_locks); |
| 96 | wake_up(&p->fl_wait); |
| 97 | } |
| 98 | } |
| 99 | } |
| 100 | } |
| 101 | |
| 102 | /* |
David Howells | e8d6c55 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 103 | * do work for a lock, including: |
| 104 | * - probing for a lock we're waiting on but didn't get immediately |
| 105 | * - extending a lock that's close to timing out |
| 106 | */ |
| 107 | void afs_lock_work(struct work_struct *work) |
| 108 | { |
| 109 | struct afs_vnode *vnode = |
| 110 | container_of(work, struct afs_vnode, lock_work.work); |
| 111 | struct file_lock *fl; |
| 112 | afs_lock_type_t type; |
| 113 | struct key *key; |
| 114 | int ret; |
| 115 | |
| 116 | _enter("{%x:%u}", vnode->fid.vid, vnode->fid.vnode); |
| 117 | |
| 118 | spin_lock(&vnode->lock); |
| 119 | |
| 120 | if (test_bit(AFS_VNODE_UNLOCKING, &vnode->flags)) { |
| 121 | _debug("unlock"); |
| 122 | spin_unlock(&vnode->lock); |
| 123 | |
| 124 | /* attempt to release the server lock; if it fails, we just |
| 125 | * wait 5 minutes and it'll time out anyway */ |
| 126 | ret = afs_vnode_release_lock(vnode, vnode->unlock_key); |
| 127 | if (ret < 0) |
| 128 | printk(KERN_WARNING "AFS:" |
| 129 | " Failed to release lock on {%x:%x} error %d\n", |
| 130 | vnode->fid.vid, vnode->fid.vnode, ret); |
| 131 | |
| 132 | spin_lock(&vnode->lock); |
| 133 | key_put(vnode->unlock_key); |
| 134 | vnode->unlock_key = NULL; |
| 135 | clear_bit(AFS_VNODE_UNLOCKING, &vnode->flags); |
| 136 | } |
| 137 | |
| 138 | /* if we've got a lock, then it must be time to extend that lock as AFS |
| 139 | * locks time out after 5 minutes */ |
| 140 | if (!list_empty(&vnode->granted_locks)) { |
| 141 | _debug("extend"); |
| 142 | |
| 143 | if (test_and_set_bit(AFS_VNODE_LOCKING, &vnode->flags)) |
| 144 | BUG(); |
| 145 | fl = list_entry(vnode->granted_locks.next, |
| 146 | struct file_lock, fl_u.afs.link); |
| 147 | key = key_get(fl->fl_file->private_data); |
| 148 | spin_unlock(&vnode->lock); |
| 149 | |
| 150 | ret = afs_vnode_extend_lock(vnode, key); |
| 151 | clear_bit(AFS_VNODE_LOCKING, &vnode->flags); |
| 152 | key_put(key); |
| 153 | switch (ret) { |
| 154 | case 0: |
| 155 | afs_schedule_lock_extension(vnode); |
| 156 | break; |
| 157 | default: |
| 158 | /* ummm... we failed to extend the lock - retry |
| 159 | * extension shortly */ |
| 160 | printk(KERN_WARNING "AFS:" |
| 161 | " Failed to extend lock on {%x:%x} error %d\n", |
| 162 | vnode->fid.vid, vnode->fid.vnode, ret); |
| 163 | queue_delayed_work(afs_lock_manager, &vnode->lock_work, |
| 164 | HZ * 10); |
| 165 | break; |
| 166 | } |
| 167 | _leave(" [extend]"); |
| 168 | return; |
| 169 | } |
| 170 | |
| 171 | /* if we don't have a granted lock, then we must've been called back by |
| 172 | * the server, and so if might be possible to get a lock we're |
| 173 | * currently waiting for */ |
| 174 | if (!list_empty(&vnode->pending_locks)) { |
| 175 | _debug("get"); |
| 176 | |
| 177 | if (test_and_set_bit(AFS_VNODE_LOCKING, &vnode->flags)) |
| 178 | BUG(); |
| 179 | fl = list_entry(vnode->pending_locks.next, |
| 180 | struct file_lock, fl_u.afs.link); |
| 181 | key = key_get(fl->fl_file->private_data); |
| 182 | type = (fl->fl_type == F_RDLCK) ? |
| 183 | AFS_LOCK_READ : AFS_LOCK_WRITE; |
| 184 | spin_unlock(&vnode->lock); |
| 185 | |
| 186 | ret = afs_vnode_set_lock(vnode, key, type); |
| 187 | clear_bit(AFS_VNODE_LOCKING, &vnode->flags); |
| 188 | switch (ret) { |
| 189 | case -EWOULDBLOCK: |
| 190 | _debug("blocked"); |
| 191 | break; |
| 192 | case 0: |
| 193 | _debug("acquired"); |
| 194 | if (type == AFS_LOCK_READ) |
| 195 | set_bit(AFS_VNODE_READLOCKED, &vnode->flags); |
| 196 | else |
| 197 | set_bit(AFS_VNODE_WRITELOCKED, &vnode->flags); |
| 198 | ret = AFS_LOCK_GRANTED; |
| 199 | default: |
| 200 | spin_lock(&vnode->lock); |
| 201 | /* the pending lock may have been withdrawn due to a |
| 202 | * signal */ |
| 203 | if (list_entry(vnode->pending_locks.next, |
| 204 | struct file_lock, fl_u.afs.link) == fl) { |
| 205 | fl->fl_u.afs.state = ret; |
| 206 | if (ret == AFS_LOCK_GRANTED) |
David Howells | ff8e210 | 2007-07-31 00:38:49 -0700 | [diff] [blame] | 207 | afs_grant_locks(vnode, fl); |
David Howells | e8d6c55 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 208 | else |
| 209 | list_del_init(&fl->fl_u.afs.link); |
| 210 | wake_up(&fl->fl_wait); |
| 211 | spin_unlock(&vnode->lock); |
| 212 | } else { |
| 213 | _debug("withdrawn"); |
| 214 | clear_bit(AFS_VNODE_READLOCKED, &vnode->flags); |
| 215 | clear_bit(AFS_VNODE_WRITELOCKED, &vnode->flags); |
| 216 | spin_unlock(&vnode->lock); |
| 217 | afs_vnode_release_lock(vnode, key); |
| 218 | if (!list_empty(&vnode->pending_locks)) |
| 219 | afs_lock_may_be_available(vnode); |
| 220 | } |
| 221 | break; |
| 222 | } |
| 223 | key_put(key); |
| 224 | _leave(" [pend]"); |
| 225 | return; |
| 226 | } |
| 227 | |
| 228 | /* looks like the lock request was withdrawn on a signal */ |
| 229 | spin_unlock(&vnode->lock); |
| 230 | _leave(" [no locks]"); |
| 231 | } |
| 232 | |
| 233 | /* |
| 234 | * pass responsibility for the unlocking of a vnode on the server to the |
| 235 | * manager thread, lest a pending signal in the calling thread interrupt |
| 236 | * AF_RXRPC |
| 237 | * - the caller must hold the vnode lock |
| 238 | */ |
| 239 | static void afs_defer_unlock(struct afs_vnode *vnode, struct key *key) |
| 240 | { |
| 241 | cancel_delayed_work(&vnode->lock_work); |
| 242 | if (!test_and_clear_bit(AFS_VNODE_READLOCKED, &vnode->flags) && |
| 243 | !test_and_clear_bit(AFS_VNODE_WRITELOCKED, &vnode->flags)) |
| 244 | BUG(); |
| 245 | if (test_and_set_bit(AFS_VNODE_UNLOCKING, &vnode->flags)) |
| 246 | BUG(); |
| 247 | vnode->unlock_key = key_get(key); |
| 248 | afs_lock_may_be_available(vnode); |
| 249 | } |
| 250 | |
| 251 | /* |
| 252 | * request a lock on a file on the server |
| 253 | */ |
| 254 | static int afs_do_setlk(struct file *file, struct file_lock *fl) |
| 255 | { |
| 256 | struct afs_vnode *vnode = AFS_FS_I(file->f_mapping->host); |
| 257 | afs_lock_type_t type; |
| 258 | struct key *key = file->private_data; |
| 259 | int ret; |
| 260 | |
| 261 | _enter("{%x:%u},%u", vnode->fid.vid, vnode->fid.vnode, fl->fl_type); |
| 262 | |
| 263 | /* only whole-file locks are supported */ |
| 264 | if (fl->fl_start != 0 || fl->fl_end != OFFSET_MAX) |
| 265 | return -EINVAL; |
| 266 | |
| 267 | ret = afs_init_lock_manager(); |
| 268 | if (ret < 0) |
| 269 | return ret; |
| 270 | |
| 271 | fl->fl_ops = &afs_lock_ops; |
| 272 | INIT_LIST_HEAD(&fl->fl_u.afs.link); |
| 273 | fl->fl_u.afs.state = AFS_LOCK_PENDING; |
| 274 | |
| 275 | type = (fl->fl_type == F_RDLCK) ? AFS_LOCK_READ : AFS_LOCK_WRITE; |
| 276 | |
| 277 | lock_kernel(); |
| 278 | |
| 279 | /* make sure we've got a callback on this file and that our view of the |
| 280 | * data version is up to date */ |
| 281 | ret = afs_vnode_fetch_status(vnode, NULL, key); |
| 282 | if (ret < 0) |
| 283 | goto error; |
| 284 | |
| 285 | if (vnode->status.lock_count != 0 && !(fl->fl_flags & FL_SLEEP)) { |
| 286 | ret = -EAGAIN; |
| 287 | goto error; |
| 288 | } |
| 289 | |
| 290 | spin_lock(&vnode->lock); |
| 291 | |
David Howells | ff8e210 | 2007-07-31 00:38:49 -0700 | [diff] [blame] | 292 | /* if we've already got a readlock on the server then we can instantly |
| 293 | * grant another readlock, irrespective of whether there are any |
| 294 | * pending writelocks */ |
| 295 | if (type == AFS_LOCK_READ && |
| 296 | vnode->flags & (1 << AFS_VNODE_READLOCKED)) { |
| 297 | _debug("instant readlock"); |
| 298 | ASSERTCMP(vnode->flags & |
| 299 | ((1 << AFS_VNODE_LOCKING) | |
| 300 | (1 << AFS_VNODE_WRITELOCKED)), ==, 0); |
| 301 | ASSERT(!list_empty(&vnode->granted_locks)); |
| 302 | goto sharing_existing_lock; |
| 303 | } |
| 304 | |
| 305 | /* if there's no-one else with a lock on this vnode, then we need to |
| 306 | * ask the server for a lock */ |
| 307 | if (list_empty(&vnode->pending_locks) && |
| 308 | list_empty(&vnode->granted_locks)) { |
| 309 | _debug("not locked"); |
| 310 | ASSERTCMP(vnode->flags & |
| 311 | ((1 << AFS_VNODE_LOCKING) | |
| 312 | (1 << AFS_VNODE_READLOCKED) | |
| 313 | (1 << AFS_VNODE_WRITELOCKED)), ==, 0); |
| 314 | list_add_tail(&fl->fl_u.afs.link, &vnode->pending_locks); |
| 315 | set_bit(AFS_VNODE_LOCKING, &vnode->flags); |
| 316 | spin_unlock(&vnode->lock); |
| 317 | |
| 318 | ret = afs_vnode_set_lock(vnode, key, type); |
| 319 | clear_bit(AFS_VNODE_LOCKING, &vnode->flags); |
| 320 | switch (ret) { |
| 321 | case 0: |
| 322 | _debug("acquired"); |
| 323 | goto acquired_server_lock; |
| 324 | case -EWOULDBLOCK: |
| 325 | _debug("would block"); |
| 326 | spin_lock(&vnode->lock); |
| 327 | ASSERT(list_empty(&vnode->granted_locks)); |
| 328 | ASSERTCMP(vnode->pending_locks.next, ==, |
| 329 | &fl->fl_u.afs.link); |
| 330 | goto wait; |
| 331 | default: |
| 332 | spin_lock(&vnode->lock); |
| 333 | list_del_init(&fl->fl_u.afs.link); |
David Howells | e8d6c55 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 334 | spin_unlock(&vnode->lock); |
David Howells | ff8e210 | 2007-07-31 00:38:49 -0700 | [diff] [blame] | 335 | goto error; |
David Howells | e8d6c55 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 336 | } |
| 337 | } |
| 338 | |
| 339 | /* otherwise, we need to wait for a local lock to become available */ |
| 340 | _debug("wait local"); |
| 341 | list_add_tail(&fl->fl_u.afs.link, &vnode->pending_locks); |
| 342 | wait: |
| 343 | if (!(fl->fl_flags & FL_SLEEP)) { |
| 344 | _debug("noblock"); |
| 345 | ret = -EAGAIN; |
| 346 | goto abort_attempt; |
| 347 | } |
| 348 | spin_unlock(&vnode->lock); |
| 349 | |
| 350 | /* now we need to sleep and wait for the lock manager thread to get the |
| 351 | * lock from the server */ |
| 352 | _debug("sleep"); |
| 353 | ret = wait_event_interruptible(fl->fl_wait, |
| 354 | fl->fl_u.afs.state <= AFS_LOCK_GRANTED); |
| 355 | if (fl->fl_u.afs.state <= AFS_LOCK_GRANTED) { |
| 356 | ret = fl->fl_u.afs.state; |
| 357 | if (ret < 0) |
| 358 | goto error; |
| 359 | spin_lock(&vnode->lock); |
| 360 | goto given_lock; |
| 361 | } |
| 362 | |
| 363 | /* we were interrupted, but someone may still be in the throes of |
| 364 | * giving us the lock */ |
| 365 | _debug("intr"); |
| 366 | ASSERTCMP(ret, ==, -ERESTARTSYS); |
| 367 | |
| 368 | spin_lock(&vnode->lock); |
| 369 | if (fl->fl_u.afs.state <= AFS_LOCK_GRANTED) { |
| 370 | ret = fl->fl_u.afs.state; |
| 371 | if (ret < 0) { |
| 372 | spin_unlock(&vnode->lock); |
| 373 | goto error; |
| 374 | } |
| 375 | goto given_lock; |
| 376 | } |
| 377 | |
| 378 | abort_attempt: |
| 379 | /* we aren't going to get the lock, either because we're unwilling to |
| 380 | * wait, or because some signal happened */ |
| 381 | _debug("abort"); |
| 382 | if (list_empty(&vnode->granted_locks) && |
| 383 | vnode->pending_locks.next == &fl->fl_u.afs.link) { |
| 384 | if (vnode->pending_locks.prev != &fl->fl_u.afs.link) { |
| 385 | /* kick the next pending lock into having a go */ |
| 386 | list_del_init(&fl->fl_u.afs.link); |
| 387 | afs_lock_may_be_available(vnode); |
| 388 | } |
| 389 | } else { |
| 390 | list_del_init(&fl->fl_u.afs.link); |
| 391 | } |
| 392 | spin_unlock(&vnode->lock); |
| 393 | goto error; |
| 394 | |
| 395 | acquired_server_lock: |
| 396 | /* we've acquired a server lock, but it needs to be renewed after 5 |
| 397 | * mins */ |
| 398 | spin_lock(&vnode->lock); |
| 399 | afs_schedule_lock_extension(vnode); |
| 400 | if (type == AFS_LOCK_READ) |
| 401 | set_bit(AFS_VNODE_READLOCKED, &vnode->flags); |
| 402 | else |
| 403 | set_bit(AFS_VNODE_WRITELOCKED, &vnode->flags); |
| 404 | sharing_existing_lock: |
| 405 | /* the lock has been granted as far as we're concerned... */ |
| 406 | fl->fl_u.afs.state = AFS_LOCK_GRANTED; |
| 407 | list_move_tail(&fl->fl_u.afs.link, &vnode->granted_locks); |
| 408 | given_lock: |
| 409 | /* ... but we do still need to get the VFS's blessing */ |
| 410 | ASSERT(!(vnode->flags & (1 << AFS_VNODE_LOCKING))); |
| 411 | ASSERT((vnode->flags & ((1 << AFS_VNODE_READLOCKED) | |
| 412 | (1 << AFS_VNODE_WRITELOCKED))) != 0); |
| 413 | ret = posix_lock_file(file, fl, NULL); |
| 414 | if (ret < 0) |
| 415 | goto vfs_rejected_lock; |
| 416 | spin_unlock(&vnode->lock); |
| 417 | |
| 418 | /* again, make sure we've got a callback on this file and, again, make |
| 419 | * sure that our view of the data version is up to date (we ignore |
| 420 | * errors incurred here and deal with the consequences elsewhere) */ |
| 421 | afs_vnode_fetch_status(vnode, NULL, key); |
| 422 | |
| 423 | error: |
| 424 | unlock_kernel(); |
| 425 | _leave(" = %d", ret); |
| 426 | return ret; |
| 427 | |
| 428 | vfs_rejected_lock: |
| 429 | /* the VFS rejected the lock we just obtained, so we have to discard |
| 430 | * what we just got */ |
| 431 | _debug("vfs refused %d", ret); |
| 432 | list_del_init(&fl->fl_u.afs.link); |
| 433 | if (list_empty(&vnode->granted_locks)) |
| 434 | afs_defer_unlock(vnode, key); |
| 435 | spin_unlock(&vnode->lock); |
| 436 | goto abort_attempt; |
| 437 | } |
| 438 | |
| 439 | /* |
| 440 | * unlock on a file on the server |
| 441 | */ |
| 442 | static int afs_do_unlk(struct file *file, struct file_lock *fl) |
| 443 | { |
| 444 | struct afs_vnode *vnode = AFS_FS_I(file->f_mapping->host); |
| 445 | struct key *key = file->private_data; |
| 446 | int ret; |
| 447 | |
| 448 | _enter("{%x:%u},%u", vnode->fid.vid, vnode->fid.vnode, fl->fl_type); |
| 449 | |
| 450 | /* only whole-file unlocks are supported */ |
| 451 | if (fl->fl_start != 0 || fl->fl_end != OFFSET_MAX) |
| 452 | return -EINVAL; |
| 453 | |
| 454 | fl->fl_ops = &afs_lock_ops; |
| 455 | INIT_LIST_HEAD(&fl->fl_u.afs.link); |
| 456 | fl->fl_u.afs.state = AFS_LOCK_PENDING; |
| 457 | |
| 458 | spin_lock(&vnode->lock); |
| 459 | ret = posix_lock_file(file, fl, NULL); |
| 460 | if (ret < 0) { |
| 461 | spin_unlock(&vnode->lock); |
| 462 | _leave(" = %d [vfs]", ret); |
| 463 | return ret; |
| 464 | } |
| 465 | |
| 466 | /* discard the server lock only if all granted locks are gone */ |
| 467 | if (list_empty(&vnode->granted_locks)) |
| 468 | afs_defer_unlock(vnode, key); |
| 469 | spin_unlock(&vnode->lock); |
| 470 | _leave(" = 0"); |
| 471 | return 0; |
| 472 | } |
| 473 | |
| 474 | /* |
| 475 | * return information about a lock we currently hold, if indeed we hold one |
| 476 | */ |
| 477 | static int afs_do_getlk(struct file *file, struct file_lock *fl) |
| 478 | { |
| 479 | struct afs_vnode *vnode = AFS_FS_I(file->f_mapping->host); |
| 480 | struct key *key = file->private_data; |
| 481 | int ret, lock_count; |
| 482 | |
| 483 | _enter(""); |
| 484 | |
| 485 | fl->fl_type = F_UNLCK; |
| 486 | |
| 487 | mutex_lock(&vnode->vfs_inode.i_mutex); |
| 488 | |
| 489 | /* check local lock records first */ |
| 490 | ret = 0; |
Andrew Morton | 275afca | 2007-07-19 01:50:35 -0700 | [diff] [blame] | 491 | posix_test_lock(file, fl); |
| 492 | if (fl->fl_type == F_UNLCK) { |
David Howells | e8d6c55 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 493 | /* no local locks; consult the server */ |
| 494 | ret = afs_vnode_fetch_status(vnode, NULL, key); |
| 495 | if (ret < 0) |
| 496 | goto error; |
| 497 | lock_count = vnode->status.lock_count; |
| 498 | if (lock_count) { |
| 499 | if (lock_count > 0) |
| 500 | fl->fl_type = F_RDLCK; |
| 501 | else |
| 502 | fl->fl_type = F_WRLCK; |
| 503 | fl->fl_start = 0; |
| 504 | fl->fl_end = OFFSET_MAX; |
| 505 | } |
| 506 | } |
| 507 | |
| 508 | error: |
| 509 | mutex_unlock(&vnode->vfs_inode.i_mutex); |
| 510 | _leave(" = %d [%hd]", ret, fl->fl_type); |
| 511 | return ret; |
| 512 | } |
| 513 | |
| 514 | /* |
| 515 | * manage POSIX locks on a file |
| 516 | */ |
| 517 | int afs_lock(struct file *file, int cmd, struct file_lock *fl) |
| 518 | { |
| 519 | struct afs_vnode *vnode = AFS_FS_I(file->f_dentry->d_inode); |
| 520 | |
| 521 | _enter("{%x:%u},%d,{t=%x,fl=%x,r=%Ld:%Ld}", |
| 522 | vnode->fid.vid, vnode->fid.vnode, cmd, |
| 523 | fl->fl_type, fl->fl_flags, |
| 524 | (long long) fl->fl_start, (long long) fl->fl_end); |
| 525 | |
| 526 | /* AFS doesn't support mandatory locks */ |
Pavel Emelyanov | fc5846e | 2007-10-01 14:41:14 -0700 | [diff] [blame^] | 527 | if (__mandatory_lock(&vnode->vfs_inode) && fl->fl_type != F_UNLCK) |
David Howells | e8d6c55 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 528 | return -ENOLCK; |
| 529 | |
| 530 | if (IS_GETLK(cmd)) |
| 531 | return afs_do_getlk(file, fl); |
| 532 | if (fl->fl_type == F_UNLCK) |
| 533 | return afs_do_unlk(file, fl); |
| 534 | return afs_do_setlk(file, fl); |
| 535 | } |
| 536 | |
| 537 | /* |
| 538 | * manage FLOCK locks on a file |
| 539 | */ |
| 540 | int afs_flock(struct file *file, int cmd, struct file_lock *fl) |
| 541 | { |
| 542 | struct afs_vnode *vnode = AFS_FS_I(file->f_dentry->d_inode); |
| 543 | |
| 544 | _enter("{%x:%u},%d,{t=%x,fl=%x}", |
| 545 | vnode->fid.vid, vnode->fid.vnode, cmd, |
| 546 | fl->fl_type, fl->fl_flags); |
| 547 | |
| 548 | /* |
| 549 | * No BSD flocks over NFS allowed. |
| 550 | * Note: we could try to fake a POSIX lock request here by |
| 551 | * using ((u32) filp | 0x80000000) or some such as the pid. |
| 552 | * Not sure whether that would be unique, though, or whether |
| 553 | * that would break in other places. |
| 554 | */ |
| 555 | if (!(fl->fl_flags & FL_FLOCK)) |
| 556 | return -ENOLCK; |
| 557 | |
| 558 | /* we're simulating flock() locks using posix locks on the server */ |
| 559 | fl->fl_owner = (fl_owner_t) file; |
| 560 | fl->fl_start = 0; |
| 561 | fl->fl_end = OFFSET_MAX; |
| 562 | |
| 563 | if (fl->fl_type == F_UNLCK) |
| 564 | return afs_do_unlk(file, fl); |
| 565 | return afs_do_setlk(file, fl); |
| 566 | } |
| 567 | |
| 568 | /* |
| 569 | * the POSIX lock management core VFS code copies the lock record and adds the |
| 570 | * copy into its own list, so we need to add that copy to the vnode's lock |
| 571 | * queue in the same place as the original (which will be deleted shortly |
| 572 | * after) |
| 573 | */ |
| 574 | static void afs_fl_copy_lock(struct file_lock *new, struct file_lock *fl) |
| 575 | { |
| 576 | _enter(""); |
| 577 | |
| 578 | list_add(&new->fl_u.afs.link, &fl->fl_u.afs.link); |
| 579 | } |
| 580 | |
| 581 | /* |
| 582 | * need to remove this lock from the vnode queue when it's removed from the |
| 583 | * VFS's list |
| 584 | */ |
| 585 | static void afs_fl_release_private(struct file_lock *fl) |
| 586 | { |
| 587 | _enter(""); |
| 588 | |
| 589 | list_del_init(&fl->fl_u.afs.link); |
| 590 | } |