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 | |
David Howells | e8d6c55 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 12 | #include "internal.h" |
| 13 | |
| 14 | #define AFS_LOCK_GRANTED 0 |
| 15 | #define AFS_LOCK_PENDING 1 |
| 16 | |
David Howells | f044c88 | 2017-11-02 15:27:45 +0000 | [diff] [blame] | 17 | struct workqueue_struct *afs_lock_manager; |
| 18 | |
David Howells | e8d6c55 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 19 | static void afs_fl_copy_lock(struct file_lock *new, struct file_lock *fl); |
| 20 | static void afs_fl_release_private(struct file_lock *fl); |
| 21 | |
Alexey Dobriyan | 6aed628 | 2009-09-21 17:01:11 -0700 | [diff] [blame] | 22 | static const struct file_lock_operations afs_lock_ops = { |
David Howells | e8d6c55 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 23 | .fl_copy_lock = afs_fl_copy_lock, |
| 24 | .fl_release_private = afs_fl_release_private, |
| 25 | }; |
| 26 | |
| 27 | /* |
David Howells | e8d6c55 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 28 | * if the callback is broken on this vnode, then the lock may now be available |
| 29 | */ |
| 30 | void afs_lock_may_be_available(struct afs_vnode *vnode) |
| 31 | { |
| 32 | _enter("{%x:%u}", vnode->fid.vid, vnode->fid.vnode); |
| 33 | |
| 34 | queue_delayed_work(afs_lock_manager, &vnode->lock_work, 0); |
| 35 | } |
| 36 | |
| 37 | /* |
| 38 | * the lock will time out in 5 minutes unless we extend it, so schedule |
| 39 | * extension in a bit less than that time |
| 40 | */ |
| 41 | static void afs_schedule_lock_extension(struct afs_vnode *vnode) |
| 42 | { |
| 43 | queue_delayed_work(afs_lock_manager, &vnode->lock_work, |
| 44 | AFS_LOCKWAIT * HZ / 2); |
| 45 | } |
| 46 | |
| 47 | /* |
David Howells | ff8e210 | 2007-07-31 00:38:49 -0700 | [diff] [blame] | 48 | * grant one or more locks (readlocks are allowed to jump the queue if the |
| 49 | * first lock in the queue is itself a readlock) |
| 50 | * - the caller must hold the vnode lock |
| 51 | */ |
| 52 | static void afs_grant_locks(struct afs_vnode *vnode, struct file_lock *fl) |
| 53 | { |
| 54 | struct file_lock *p, *_p; |
| 55 | |
| 56 | list_move_tail(&fl->fl_u.afs.link, &vnode->granted_locks); |
| 57 | if (fl->fl_type == F_RDLCK) { |
| 58 | list_for_each_entry_safe(p, _p, &vnode->pending_locks, |
| 59 | fl_u.afs.link) { |
| 60 | if (p->fl_type == F_RDLCK) { |
| 61 | p->fl_u.afs.state = AFS_LOCK_GRANTED; |
| 62 | list_move_tail(&p->fl_u.afs.link, |
| 63 | &vnode->granted_locks); |
| 64 | wake_up(&p->fl_wait); |
| 65 | } |
| 66 | } |
| 67 | } |
| 68 | } |
| 69 | |
| 70 | /* |
David Howells | d2ddc77 | 2017-11-02 15:27:50 +0000 | [diff] [blame] | 71 | * Get a lock on a file |
| 72 | */ |
| 73 | static int afs_set_lock(struct afs_vnode *vnode, struct key *key, |
| 74 | afs_lock_type_t type) |
| 75 | { |
| 76 | struct afs_fs_cursor fc; |
| 77 | int ret; |
| 78 | |
| 79 | _enter("%s{%x:%u.%u},%x,%u", |
| 80 | vnode->volume->name, |
| 81 | vnode->fid.vid, |
| 82 | vnode->fid.vnode, |
| 83 | vnode->fid.unique, |
| 84 | key_serial(key), type); |
| 85 | |
| 86 | ret = -ERESTARTSYS; |
| 87 | if (afs_begin_vnode_operation(&fc, vnode, key)) { |
| 88 | while (afs_select_fileserver(&fc)) { |
| 89 | fc.cb_break = vnode->cb_break + vnode->cb_s_break; |
| 90 | afs_fs_set_lock(&fc, type); |
| 91 | } |
| 92 | |
| 93 | afs_check_for_remote_deletion(&fc, fc.vnode); |
| 94 | afs_vnode_commit_status(&fc, vnode, fc.cb_break); |
| 95 | ret = afs_end_vnode_operation(&fc); |
| 96 | } |
| 97 | |
| 98 | _leave(" = %d", ret); |
| 99 | return ret; |
| 100 | } |
| 101 | |
| 102 | /* |
| 103 | * Extend a lock on a file |
| 104 | */ |
| 105 | static int afs_extend_lock(struct afs_vnode *vnode, struct key *key) |
| 106 | { |
| 107 | struct afs_fs_cursor fc; |
| 108 | int ret; |
| 109 | |
| 110 | _enter("%s{%x:%u.%u},%x", |
| 111 | vnode->volume->name, |
| 112 | vnode->fid.vid, |
| 113 | vnode->fid.vnode, |
| 114 | vnode->fid.unique, |
| 115 | key_serial(key)); |
| 116 | |
| 117 | ret = -ERESTARTSYS; |
| 118 | if (afs_begin_vnode_operation(&fc, vnode, key)) { |
| 119 | while (afs_select_current_fileserver(&fc)) { |
| 120 | fc.cb_break = vnode->cb_break + vnode->cb_s_break; |
| 121 | afs_fs_extend_lock(&fc); |
| 122 | } |
| 123 | |
| 124 | afs_check_for_remote_deletion(&fc, fc.vnode); |
| 125 | afs_vnode_commit_status(&fc, vnode, fc.cb_break); |
| 126 | ret = afs_end_vnode_operation(&fc); |
| 127 | } |
| 128 | |
| 129 | _leave(" = %d", ret); |
| 130 | return ret; |
| 131 | } |
| 132 | |
| 133 | /* |
| 134 | * Release a lock on a file |
| 135 | */ |
| 136 | static int afs_release_lock(struct afs_vnode *vnode, struct key *key) |
| 137 | { |
| 138 | struct afs_fs_cursor fc; |
| 139 | int ret; |
| 140 | |
| 141 | _enter("%s{%x:%u.%u},%x", |
| 142 | vnode->volume->name, |
| 143 | vnode->fid.vid, |
| 144 | vnode->fid.vnode, |
| 145 | vnode->fid.unique, |
| 146 | key_serial(key)); |
| 147 | |
| 148 | ret = -ERESTARTSYS; |
| 149 | if (afs_begin_vnode_operation(&fc, vnode, key)) { |
| 150 | while (afs_select_current_fileserver(&fc)) { |
| 151 | fc.cb_break = vnode->cb_break + vnode->cb_s_break; |
| 152 | afs_fs_release_lock(&fc); |
| 153 | } |
| 154 | |
| 155 | afs_check_for_remote_deletion(&fc, fc.vnode); |
| 156 | afs_vnode_commit_status(&fc, vnode, fc.cb_break); |
| 157 | ret = afs_end_vnode_operation(&fc); |
| 158 | } |
| 159 | |
| 160 | _leave(" = %d", ret); |
| 161 | return ret; |
| 162 | } |
| 163 | |
| 164 | /* |
David Howells | e8d6c55 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 165 | * do work for a lock, including: |
| 166 | * - probing for a lock we're waiting on but didn't get immediately |
| 167 | * - extending a lock that's close to timing out |
| 168 | */ |
| 169 | void afs_lock_work(struct work_struct *work) |
| 170 | { |
| 171 | struct afs_vnode *vnode = |
| 172 | container_of(work, struct afs_vnode, lock_work.work); |
David Howells | 0fafdc9 | 2017-11-13 16:59:50 +0000 | [diff] [blame] | 173 | struct file_lock *fl, *next; |
David Howells | e8d6c55 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 174 | afs_lock_type_t type; |
| 175 | struct key *key; |
| 176 | int ret; |
| 177 | |
| 178 | _enter("{%x:%u}", vnode->fid.vid, vnode->fid.vnode); |
| 179 | |
| 180 | spin_lock(&vnode->lock); |
| 181 | |
David Howells | 0fafdc9 | 2017-11-13 16:59:50 +0000 | [diff] [blame] | 182 | again: |
| 183 | _debug("wstate %u for %p", vnode->lock_state, vnode); |
| 184 | switch (vnode->lock_state) { |
| 185 | case AFS_VNODE_LOCK_NEED_UNLOCK: |
David Howells | e8d6c55 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 186 | _debug("unlock"); |
David Howells | 0fafdc9 | 2017-11-13 16:59:50 +0000 | [diff] [blame] | 187 | vnode->lock_state = AFS_VNODE_LOCK_UNLOCKING; |
David Howells | e8d6c55 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 188 | spin_unlock(&vnode->lock); |
| 189 | |
| 190 | /* attempt to release the server lock; if it fails, we just |
David Howells | 0fafdc9 | 2017-11-13 16:59:50 +0000 | [diff] [blame] | 191 | * wait 5 minutes and it'll expire anyway */ |
| 192 | ret = afs_release_lock(vnode, vnode->lock_key); |
David Howells | e8d6c55 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 193 | if (ret < 0) |
| 194 | printk(KERN_WARNING "AFS:" |
| 195 | " Failed to release lock on {%x:%x} error %d\n", |
| 196 | vnode->fid.vid, vnode->fid.vnode, ret); |
| 197 | |
| 198 | spin_lock(&vnode->lock); |
David Howells | 0fafdc9 | 2017-11-13 16:59:50 +0000 | [diff] [blame] | 199 | key_put(vnode->lock_key); |
| 200 | vnode->lock_key = NULL; |
| 201 | vnode->lock_state = AFS_VNODE_LOCK_NONE; |
David Howells | e8d6c55 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 202 | |
David Howells | 0fafdc9 | 2017-11-13 16:59:50 +0000 | [diff] [blame] | 203 | if (list_empty(&vnode->pending_locks)) { |
| 204 | spin_unlock(&vnode->lock); |
| 205 | return; |
| 206 | } |
| 207 | |
| 208 | /* The new front of the queue now owns the state variables. */ |
| 209 | next = list_entry(vnode->pending_locks.next, |
| 210 | struct file_lock, fl_u.afs.link); |
| 211 | vnode->lock_key = afs_file_key(next->fl_file); |
| 212 | vnode->lock_type = (next->fl_type == F_RDLCK) ? AFS_LOCK_READ : AFS_LOCK_WRITE; |
| 213 | vnode->lock_state = AFS_VNODE_LOCK_WAITING_FOR_CB; |
| 214 | goto again; |
| 215 | |
| 216 | /* If we've already got a lock, then it must be time to extend that |
| 217 | * lock as AFS locks time out after 5 minutes. |
| 218 | */ |
| 219 | case AFS_VNODE_LOCK_GRANTED: |
David Howells | e8d6c55 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 220 | _debug("extend"); |
| 221 | |
David Howells | 0fafdc9 | 2017-11-13 16:59:50 +0000 | [diff] [blame] | 222 | ASSERT(!list_empty(&vnode->granted_locks)); |
| 223 | |
| 224 | key = key_get(vnode->lock_key); |
| 225 | vnode->lock_state = AFS_VNODE_LOCK_EXTENDING; |
David Howells | e8d6c55 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 226 | spin_unlock(&vnode->lock); |
| 227 | |
David Howells | 0fafdc9 | 2017-11-13 16:59:50 +0000 | [diff] [blame] | 228 | ret = afs_extend_lock(vnode, key); /* RPC */ |
David Howells | e8d6c55 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 229 | key_put(key); |
David Howells | 0fafdc9 | 2017-11-13 16:59:50 +0000 | [diff] [blame] | 230 | |
| 231 | if (ret < 0) |
| 232 | pr_warning("AFS: Failed to extend lock on {%x:%x} error %d\n", |
| 233 | vnode->fid.vid, vnode->fid.vnode, ret); |
| 234 | |
| 235 | spin_lock(&vnode->lock); |
| 236 | |
| 237 | if (vnode->lock_state != AFS_VNODE_LOCK_EXTENDING) |
| 238 | goto again; |
| 239 | vnode->lock_state = AFS_VNODE_LOCK_GRANTED; |
| 240 | |
| 241 | if (ret == 0) |
David Howells | e8d6c55 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 242 | afs_schedule_lock_extension(vnode); |
David Howells | 0fafdc9 | 2017-11-13 16:59:50 +0000 | [diff] [blame] | 243 | else |
David Howells | e8d6c55 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 244 | queue_delayed_work(afs_lock_manager, &vnode->lock_work, |
| 245 | HZ * 10); |
David Howells | 0fafdc9 | 2017-11-13 16:59:50 +0000 | [diff] [blame] | 246 | spin_unlock(&vnode->lock); |
| 247 | _leave(" [ext]"); |
David Howells | e8d6c55 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 248 | return; |
David Howells | e8d6c55 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 249 | |
David Howells | 0fafdc9 | 2017-11-13 16:59:50 +0000 | [diff] [blame] | 250 | /* If we don't have a granted lock, then we must've been called |
| 251 | * back by the server, and so if might be possible to get a |
| 252 | * lock we're currently waiting for. |
| 253 | */ |
| 254 | case AFS_VNODE_LOCK_WAITING_FOR_CB: |
David Howells | e8d6c55 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 255 | _debug("get"); |
| 256 | |
David Howells | 0fafdc9 | 2017-11-13 16:59:50 +0000 | [diff] [blame] | 257 | key = key_get(vnode->lock_key); |
| 258 | type = vnode->lock_type; |
| 259 | vnode->lock_state = AFS_VNODE_LOCK_SETTING; |
David Howells | e8d6c55 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 260 | spin_unlock(&vnode->lock); |
| 261 | |
David Howells | 0fafdc9 | 2017-11-13 16:59:50 +0000 | [diff] [blame] | 262 | ret = afs_set_lock(vnode, key, type); /* RPC */ |
| 263 | key_put(key); |
| 264 | |
| 265 | spin_lock(&vnode->lock); |
David Howells | e8d6c55 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 266 | switch (ret) { |
| 267 | case -EWOULDBLOCK: |
| 268 | _debug("blocked"); |
| 269 | break; |
| 270 | case 0: |
| 271 | _debug("acquired"); |
David Howells | 0fafdc9 | 2017-11-13 16:59:50 +0000 | [diff] [blame] | 272 | vnode->lock_state = AFS_VNODE_LOCK_GRANTED; |
| 273 | /* Fall through */ |
David Howells | e8d6c55 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 274 | default: |
David Howells | 0fafdc9 | 2017-11-13 16:59:50 +0000 | [diff] [blame] | 275 | /* Pass the lock or the error onto the first locker in |
| 276 | * the list - if they're looking for this type of lock. |
| 277 | * If they're not, we assume that whoever asked for it |
| 278 | * took a signal. |
| 279 | */ |
| 280 | if (list_empty(&vnode->pending_locks)) { |
David Howells | e8d6c55 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 281 | _debug("withdrawn"); |
David Howells | 0fafdc9 | 2017-11-13 16:59:50 +0000 | [diff] [blame] | 282 | vnode->lock_state = AFS_VNODE_LOCK_NEED_UNLOCK; |
| 283 | goto again; |
David Howells | e8d6c55 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 284 | } |
David Howells | 0fafdc9 | 2017-11-13 16:59:50 +0000 | [diff] [blame] | 285 | |
| 286 | fl = list_entry(vnode->pending_locks.next, |
| 287 | struct file_lock, fl_u.afs.link); |
| 288 | type = (fl->fl_type == F_RDLCK) ? AFS_LOCK_READ : AFS_LOCK_WRITE; |
| 289 | if (vnode->lock_type != type) { |
| 290 | _debug("changed"); |
| 291 | vnode->lock_state = AFS_VNODE_LOCK_NEED_UNLOCK; |
| 292 | goto again; |
| 293 | } |
| 294 | |
| 295 | fl->fl_u.afs.state = ret; |
| 296 | if (ret == 0) |
| 297 | afs_grant_locks(vnode, fl); |
| 298 | else |
| 299 | list_del_init(&fl->fl_u.afs.link); |
| 300 | wake_up(&fl->fl_wait); |
| 301 | spin_unlock(&vnode->lock); |
| 302 | _leave(" [granted]"); |
| 303 | return; |
David Howells | e8d6c55 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 304 | } |
David Howells | 0fafdc9 | 2017-11-13 16:59:50 +0000 | [diff] [blame] | 305 | |
| 306 | default: |
| 307 | /* Looks like a lock request was withdrawn. */ |
| 308 | spin_unlock(&vnode->lock); |
| 309 | _leave(" [no]"); |
David Howells | e8d6c55 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 310 | return; |
| 311 | } |
David Howells | e8d6c55 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 312 | } |
| 313 | |
| 314 | /* |
| 315 | * pass responsibility for the unlocking of a vnode on the server to the |
| 316 | * manager thread, lest a pending signal in the calling thread interrupt |
| 317 | * AF_RXRPC |
| 318 | * - the caller must hold the vnode lock |
| 319 | */ |
David Howells | 0fafdc9 | 2017-11-13 16:59:50 +0000 | [diff] [blame] | 320 | static void afs_defer_unlock(struct afs_vnode *vnode) |
David Howells | e8d6c55 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 321 | { |
David Howells | 0fafdc9 | 2017-11-13 16:59:50 +0000 | [diff] [blame] | 322 | _enter(""); |
| 323 | |
| 324 | if (vnode->lock_state == AFS_VNODE_LOCK_GRANTED || |
| 325 | vnode->lock_state == AFS_VNODE_LOCK_EXTENDING) { |
| 326 | cancel_delayed_work(&vnode->lock_work); |
| 327 | |
| 328 | vnode->lock_state = AFS_VNODE_LOCK_NEED_UNLOCK; |
| 329 | afs_lock_may_be_available(vnode); |
| 330 | } |
| 331 | } |
| 332 | |
| 333 | /* |
| 334 | * Check that our view of the file metadata is up to date and check to see |
| 335 | * whether we think that we have a locking permit. |
| 336 | */ |
| 337 | static int afs_do_setlk_check(struct afs_vnode *vnode, struct key *key, |
| 338 | afs_lock_type_t type, bool can_sleep) |
| 339 | { |
| 340 | afs_access_t access; |
| 341 | int ret; |
| 342 | |
| 343 | /* Make sure we've got a callback on this file and that our view of the |
| 344 | * data version is up to date. |
| 345 | */ |
| 346 | ret = afs_validate(vnode, key); |
| 347 | if (ret < 0) |
| 348 | return ret; |
| 349 | |
| 350 | /* Check the permission set to see if we're actually going to be |
| 351 | * allowed to get a lock on this file. |
| 352 | */ |
| 353 | ret = afs_check_permit(vnode, key, &access); |
| 354 | if (ret < 0) |
| 355 | return ret; |
| 356 | |
| 357 | /* At a rough estimation, you need LOCK, WRITE or INSERT perm to |
| 358 | * read-lock a file and WRITE or INSERT perm to write-lock a file. |
| 359 | * |
| 360 | * We can't rely on the server to do this for us since if we want to |
| 361 | * share a read lock that we already have, we won't go the server. |
| 362 | */ |
| 363 | if (type == AFS_LOCK_READ) { |
| 364 | if (!(access & (AFS_ACE_INSERT | AFS_ACE_WRITE | AFS_ACE_LOCK))) |
| 365 | return -EACCES; |
| 366 | if (vnode->status.lock_count == -1 && !can_sleep) |
| 367 | return -EAGAIN; /* Write locked */ |
| 368 | } else { |
| 369 | if (!(access & (AFS_ACE_INSERT | AFS_ACE_WRITE))) |
| 370 | return -EACCES; |
| 371 | if (vnode->status.lock_count != 0 && !can_sleep) |
| 372 | return -EAGAIN; /* Locked */ |
| 373 | } |
| 374 | |
| 375 | return 0; |
| 376 | } |
| 377 | |
| 378 | /* |
| 379 | * Remove the front runner from the pending queue. |
| 380 | * - The caller must hold vnode->lock. |
| 381 | */ |
| 382 | static void afs_dequeue_lock(struct afs_vnode *vnode, struct file_lock *fl) |
| 383 | { |
| 384 | struct file_lock *next; |
| 385 | |
| 386 | _enter(""); |
| 387 | |
| 388 | /* ->lock_type, ->lock_key and ->lock_state only belong to this |
| 389 | * file_lock if we're at the front of the pending queue or if we have |
| 390 | * the lock granted or if the lock_state is NEED_UNLOCK or UNLOCKING. |
| 391 | */ |
| 392 | if (vnode->granted_locks.next == &fl->fl_u.afs.link && |
| 393 | vnode->granted_locks.prev == &fl->fl_u.afs.link) { |
| 394 | list_del_init(&fl->fl_u.afs.link); |
| 395 | afs_defer_unlock(vnode); |
| 396 | return; |
| 397 | } |
| 398 | |
| 399 | if (!list_empty(&vnode->granted_locks) || |
| 400 | vnode->pending_locks.next != &fl->fl_u.afs.link) { |
| 401 | list_del_init(&fl->fl_u.afs.link); |
| 402 | return; |
| 403 | } |
| 404 | |
| 405 | list_del_init(&fl->fl_u.afs.link); |
| 406 | key_put(vnode->lock_key); |
| 407 | vnode->lock_key = NULL; |
| 408 | vnode->lock_state = AFS_VNODE_LOCK_NONE; |
| 409 | |
| 410 | if (list_empty(&vnode->pending_locks)) |
| 411 | return; |
| 412 | |
| 413 | /* The new front of the queue now owns the state variables. */ |
| 414 | next = list_entry(vnode->pending_locks.next, |
| 415 | struct file_lock, fl_u.afs.link); |
| 416 | vnode->lock_key = afs_file_key(next->fl_file); |
| 417 | vnode->lock_type = (next->fl_type == F_RDLCK) ? AFS_LOCK_READ : AFS_LOCK_WRITE; |
| 418 | vnode->lock_state = AFS_VNODE_LOCK_WAITING_FOR_CB; |
David Howells | e8d6c55 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 419 | afs_lock_may_be_available(vnode); |
| 420 | } |
| 421 | |
| 422 | /* |
| 423 | * request a lock on a file on the server |
| 424 | */ |
| 425 | static int afs_do_setlk(struct file *file, struct file_lock *fl) |
| 426 | { |
David Howells | 0fafdc9 | 2017-11-13 16:59:50 +0000 | [diff] [blame] | 427 | struct inode *inode = locks_inode(file); |
Jeff Layton | 1c8c601 | 2013-06-21 08:58:15 -0400 | [diff] [blame] | 428 | struct afs_vnode *vnode = AFS_FS_I(inode); |
David Howells | e8d6c55 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 429 | afs_lock_type_t type; |
David Howells | 215804a | 2017-11-02 15:27:52 +0000 | [diff] [blame] | 430 | struct key *key = afs_file_key(file); |
David Howells | e8d6c55 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 431 | int ret; |
| 432 | |
| 433 | _enter("{%x:%u},%u", vnode->fid.vid, vnode->fid.vnode, fl->fl_type); |
| 434 | |
| 435 | /* only whole-file locks are supported */ |
| 436 | if (fl->fl_start != 0 || fl->fl_end != OFFSET_MAX) |
| 437 | return -EINVAL; |
| 438 | |
David Howells | e8d6c55 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 439 | fl->fl_ops = &afs_lock_ops; |
| 440 | INIT_LIST_HEAD(&fl->fl_u.afs.link); |
| 441 | fl->fl_u.afs.state = AFS_LOCK_PENDING; |
| 442 | |
| 443 | type = (fl->fl_type == F_RDLCK) ? AFS_LOCK_READ : AFS_LOCK_WRITE; |
| 444 | |
David Howells | 0fafdc9 | 2017-11-13 16:59:50 +0000 | [diff] [blame] | 445 | ret = afs_do_setlk_check(vnode, key, type, fl->fl_flags & FL_SLEEP); |
David Howells | e8d6c55 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 446 | if (ret < 0) |
David Howells | 0fafdc9 | 2017-11-13 16:59:50 +0000 | [diff] [blame] | 447 | return ret; |
David Howells | e8d6c55 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 448 | |
| 449 | spin_lock(&vnode->lock); |
| 450 | |
David Howells | 0fafdc9 | 2017-11-13 16:59:50 +0000 | [diff] [blame] | 451 | /* If we've already got a readlock on the server then we instantly |
David Howells | ff8e210 | 2007-07-31 00:38:49 -0700 | [diff] [blame] | 452 | * grant another readlock, irrespective of whether there are any |
David Howells | 0fafdc9 | 2017-11-13 16:59:50 +0000 | [diff] [blame] | 453 | * pending writelocks. |
| 454 | */ |
David Howells | ff8e210 | 2007-07-31 00:38:49 -0700 | [diff] [blame] | 455 | if (type == AFS_LOCK_READ && |
David Howells | 0fafdc9 | 2017-11-13 16:59:50 +0000 | [diff] [blame] | 456 | vnode->lock_state == AFS_VNODE_LOCK_GRANTED && |
| 457 | vnode->lock_type == AFS_LOCK_READ) { |
David Howells | ff8e210 | 2007-07-31 00:38:49 -0700 | [diff] [blame] | 458 | _debug("instant readlock"); |
David Howells | ff8e210 | 2007-07-31 00:38:49 -0700 | [diff] [blame] | 459 | ASSERT(!list_empty(&vnode->granted_locks)); |
David Howells | 0fafdc9 | 2017-11-13 16:59:50 +0000 | [diff] [blame] | 460 | goto share_existing_lock; |
David Howells | ff8e210 | 2007-07-31 00:38:49 -0700 | [diff] [blame] | 461 | } |
| 462 | |
David Howells | e8d6c55 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 463 | list_add_tail(&fl->fl_u.afs.link, &vnode->pending_locks); |
David Howells | 0fafdc9 | 2017-11-13 16:59:50 +0000 | [diff] [blame] | 464 | |
| 465 | if (vnode->lock_state != AFS_VNODE_LOCK_NONE) |
| 466 | goto need_to_wait; |
| 467 | |
| 468 | /* We don't have a lock on this vnode and we aren't currently waiting |
| 469 | * for one either, so ask the server for a lock. |
| 470 | * |
| 471 | * Note that we need to be careful if we get interrupted by a signal |
| 472 | * after dispatching the request as we may still get the lock, even |
| 473 | * though we don't wait for the reply (it's not too bad a problem - the |
| 474 | * lock will expire in 10 mins anyway). |
| 475 | */ |
| 476 | _debug("not locked"); |
| 477 | vnode->lock_key = key_get(key); |
| 478 | vnode->lock_type = type; |
| 479 | vnode->lock_state = AFS_VNODE_LOCK_SETTING; |
David Howells | e8d6c55 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 480 | spin_unlock(&vnode->lock); |
| 481 | |
David Howells | 0fafdc9 | 2017-11-13 16:59:50 +0000 | [diff] [blame] | 482 | ret = afs_set_lock(vnode, key, type); /* RPC */ |
David Howells | e8d6c55 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 483 | |
| 484 | spin_lock(&vnode->lock); |
David Howells | 0fafdc9 | 2017-11-13 16:59:50 +0000 | [diff] [blame] | 485 | switch (ret) { |
| 486 | default: |
| 487 | goto abort_attempt; |
| 488 | |
| 489 | case -EWOULDBLOCK: |
| 490 | /* The server doesn't have a lock-waiting queue, so the client |
| 491 | * will have to retry. The server will break the outstanding |
| 492 | * callbacks on a file when a lock is released. |
| 493 | */ |
| 494 | _debug("would block"); |
| 495 | ASSERT(list_empty(&vnode->granted_locks)); |
| 496 | ASSERTCMP(vnode->pending_locks.next, ==, &fl->fl_u.afs.link); |
| 497 | vnode->lock_state = AFS_VNODE_LOCK_WAITING_FOR_CB; |
| 498 | goto need_to_wait; |
| 499 | |
| 500 | case 0: |
| 501 | _debug("acquired"); |
| 502 | break; |
David Howells | e8d6c55 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 503 | } |
| 504 | |
David Howells | 0fafdc9 | 2017-11-13 16:59:50 +0000 | [diff] [blame] | 505 | /* we've acquired a server lock, but it needs to be renewed after 5 |
| 506 | * mins */ |
| 507 | vnode->lock_state = AFS_VNODE_LOCK_GRANTED; |
| 508 | afs_schedule_lock_extension(vnode); |
| 509 | |
| 510 | share_existing_lock: |
| 511 | /* the lock has been granted as far as we're concerned... */ |
| 512 | fl->fl_u.afs.state = AFS_LOCK_GRANTED; |
| 513 | list_move_tail(&fl->fl_u.afs.link, &vnode->granted_locks); |
| 514 | |
| 515 | given_lock: |
| 516 | /* ... but we do still need to get the VFS's blessing */ |
| 517 | spin_unlock(&vnode->lock); |
| 518 | |
| 519 | ret = posix_lock_file(file, fl, NULL); |
| 520 | if (ret < 0) |
| 521 | goto vfs_rejected_lock; |
| 522 | |
| 523 | /* Again, make sure we've got a callback on this file and, again, make |
| 524 | * sure that our view of the data version is up to date (we ignore |
| 525 | * errors incurred here and deal with the consequences elsewhere). |
| 526 | */ |
| 527 | afs_validate(vnode, key); |
| 528 | _leave(" = 0"); |
| 529 | return 0; |
| 530 | |
| 531 | need_to_wait: |
| 532 | /* We're going to have to wait. Either this client doesn't have a lock |
| 533 | * on the server yet and we need to wait for a callback to occur, or |
| 534 | * the client does have a lock on the server, but it belongs to some |
| 535 | * other process(es) and is incompatible with the lock we want. |
| 536 | */ |
| 537 | ret = -EAGAIN; |
| 538 | if (fl->fl_flags & FL_SLEEP) { |
| 539 | spin_unlock(&vnode->lock); |
| 540 | |
| 541 | _debug("sleep"); |
| 542 | ret = wait_event_interruptible(fl->fl_wait, |
| 543 | fl->fl_u.afs.state != AFS_LOCK_PENDING); |
| 544 | |
| 545 | spin_lock(&vnode->lock); |
| 546 | } |
| 547 | |
| 548 | if (fl->fl_u.afs.state == AFS_LOCK_GRANTED) |
| 549 | goto given_lock; |
| 550 | if (fl->fl_u.afs.state < 0) |
| 551 | ret = fl->fl_u.afs.state; |
| 552 | |
David Howells | e8d6c55 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 553 | abort_attempt: |
| 554 | /* we aren't going to get the lock, either because we're unwilling to |
| 555 | * wait, or because some signal happened */ |
| 556 | _debug("abort"); |
David Howells | 0fafdc9 | 2017-11-13 16:59:50 +0000 | [diff] [blame] | 557 | afs_dequeue_lock(vnode, fl); |
| 558 | |
| 559 | error_unlock: |
David Howells | e8d6c55 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 560 | spin_unlock(&vnode->lock); |
David Howells | e8d6c55 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 561 | _leave(" = %d", ret); |
| 562 | return ret; |
| 563 | |
| 564 | vfs_rejected_lock: |
David Howells | 0fafdc9 | 2017-11-13 16:59:50 +0000 | [diff] [blame] | 565 | /* The VFS rejected the lock we just obtained, so we have to discard |
| 566 | * what we just got. We defer this to the lock manager work item to |
| 567 | * deal with. |
| 568 | */ |
David Howells | e8d6c55 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 569 | _debug("vfs refused %d", ret); |
David Howells | 0fafdc9 | 2017-11-13 16:59:50 +0000 | [diff] [blame] | 570 | spin_lock(&vnode->lock); |
David Howells | e8d6c55 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 571 | list_del_init(&fl->fl_u.afs.link); |
| 572 | if (list_empty(&vnode->granted_locks)) |
David Howells | 0fafdc9 | 2017-11-13 16:59:50 +0000 | [diff] [blame] | 573 | afs_defer_unlock(vnode); |
| 574 | goto error_unlock; |
David Howells | e8d6c55 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 575 | } |
| 576 | |
| 577 | /* |
| 578 | * unlock on a file on the server |
| 579 | */ |
| 580 | static int afs_do_unlk(struct file *file, struct file_lock *fl) |
| 581 | { |
David Howells | 0fafdc9 | 2017-11-13 16:59:50 +0000 | [diff] [blame] | 582 | struct afs_vnode *vnode = AFS_FS_I(locks_inode(file)); |
David Howells | e8d6c55 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 583 | int ret; |
| 584 | |
| 585 | _enter("{%x:%u},%u", vnode->fid.vid, vnode->fid.vnode, fl->fl_type); |
| 586 | |
David Howells | 0fafdc9 | 2017-11-13 16:59:50 +0000 | [diff] [blame] | 587 | /* Flush all pending writes before doing anything with locks. */ |
| 588 | vfs_fsync(file, 0); |
| 589 | |
David Howells | e8d6c55 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 590 | /* only whole-file unlocks are supported */ |
| 591 | if (fl->fl_start != 0 || fl->fl_end != OFFSET_MAX) |
| 592 | return -EINVAL; |
| 593 | |
David Howells | e8d6c55 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 594 | ret = posix_lock_file(file, fl, NULL); |
David Howells | 0fafdc9 | 2017-11-13 16:59:50 +0000 | [diff] [blame] | 595 | _leave(" = %d [%u]", ret, vnode->lock_state); |
| 596 | return ret; |
David Howells | e8d6c55 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 597 | } |
| 598 | |
| 599 | /* |
| 600 | * return information about a lock we currently hold, if indeed we hold one |
| 601 | */ |
| 602 | static int afs_do_getlk(struct file *file, struct file_lock *fl) |
| 603 | { |
David Howells | 0fafdc9 | 2017-11-13 16:59:50 +0000 | [diff] [blame] | 604 | struct afs_vnode *vnode = AFS_FS_I(locks_inode(file)); |
David Howells | 215804a | 2017-11-02 15:27:52 +0000 | [diff] [blame] | 605 | struct key *key = afs_file_key(file); |
David Howells | e8d6c55 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 606 | int ret, lock_count; |
| 607 | |
| 608 | _enter(""); |
| 609 | |
| 610 | fl->fl_type = F_UNLCK; |
| 611 | |
David Howells | e8d6c55 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 612 | /* check local lock records first */ |
Andrew Morton | 275afca | 2007-07-19 01:50:35 -0700 | [diff] [blame] | 613 | posix_test_lock(file, fl); |
| 614 | if (fl->fl_type == F_UNLCK) { |
David Howells | e8d6c55 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 615 | /* no local locks; consult the server */ |
David Howells | d2ddc77 | 2017-11-02 15:27:50 +0000 | [diff] [blame] | 616 | ret = afs_fetch_status(vnode, key); |
David Howells | e8d6c55 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 617 | if (ret < 0) |
| 618 | goto error; |
David Howells | 0fafdc9 | 2017-11-13 16:59:50 +0000 | [diff] [blame] | 619 | |
| 620 | lock_count = READ_ONCE(vnode->status.lock_count); |
| 621 | if (lock_count > 0) |
| 622 | fl->fl_type = F_RDLCK; |
| 623 | else |
| 624 | fl->fl_type = F_WRLCK; |
| 625 | fl->fl_start = 0; |
| 626 | fl->fl_end = OFFSET_MAX; |
David Howells | e8d6c55 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 627 | } |
| 628 | |
David Howells | 0fafdc9 | 2017-11-13 16:59:50 +0000 | [diff] [blame] | 629 | ret = 0; |
David Howells | e8d6c55 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 630 | error: |
David Howells | e8d6c55 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 631 | _leave(" = %d [%hd]", ret, fl->fl_type); |
| 632 | return ret; |
| 633 | } |
| 634 | |
| 635 | /* |
| 636 | * manage POSIX locks on a file |
| 637 | */ |
| 638 | int afs_lock(struct file *file, int cmd, struct file_lock *fl) |
| 639 | { |
David Howells | 0fafdc9 | 2017-11-13 16:59:50 +0000 | [diff] [blame] | 640 | struct afs_vnode *vnode = AFS_FS_I(locks_inode(file)); |
David Howells | e8d6c55 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 641 | |
| 642 | _enter("{%x:%u},%d,{t=%x,fl=%x,r=%Ld:%Ld}", |
| 643 | vnode->fid.vid, vnode->fid.vnode, cmd, |
| 644 | fl->fl_type, fl->fl_flags, |
| 645 | (long long) fl->fl_start, (long long) fl->fl_end); |
| 646 | |
| 647 | /* AFS doesn't support mandatory locks */ |
Pavel Emelyanov | fc5846e | 2007-10-01 14:41:14 -0700 | [diff] [blame] | 648 | if (__mandatory_lock(&vnode->vfs_inode) && fl->fl_type != F_UNLCK) |
David Howells | e8d6c55 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 649 | return -ENOLCK; |
| 650 | |
| 651 | if (IS_GETLK(cmd)) |
| 652 | return afs_do_getlk(file, fl); |
| 653 | if (fl->fl_type == F_UNLCK) |
| 654 | return afs_do_unlk(file, fl); |
| 655 | return afs_do_setlk(file, fl); |
| 656 | } |
| 657 | |
| 658 | /* |
| 659 | * manage FLOCK locks on a file |
| 660 | */ |
| 661 | int afs_flock(struct file *file, int cmd, struct file_lock *fl) |
| 662 | { |
David Howells | 0fafdc9 | 2017-11-13 16:59:50 +0000 | [diff] [blame] | 663 | struct afs_vnode *vnode = AFS_FS_I(locks_inode(file)); |
David Howells | e8d6c55 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 664 | |
| 665 | _enter("{%x:%u},%d,{t=%x,fl=%x}", |
| 666 | vnode->fid.vid, vnode->fid.vnode, cmd, |
| 667 | fl->fl_type, fl->fl_flags); |
| 668 | |
| 669 | /* |
| 670 | * No BSD flocks over NFS allowed. |
| 671 | * Note: we could try to fake a POSIX lock request here by |
| 672 | * using ((u32) filp | 0x80000000) or some such as the pid. |
| 673 | * Not sure whether that would be unique, though, or whether |
| 674 | * that would break in other places. |
| 675 | */ |
| 676 | if (!(fl->fl_flags & FL_FLOCK)) |
| 677 | return -ENOLCK; |
| 678 | |
| 679 | /* we're simulating flock() locks using posix locks on the server */ |
David Howells | e8d6c55 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 680 | if (fl->fl_type == F_UNLCK) |
| 681 | return afs_do_unlk(file, fl); |
| 682 | return afs_do_setlk(file, fl); |
| 683 | } |
| 684 | |
| 685 | /* |
| 686 | * the POSIX lock management core VFS code copies the lock record and adds the |
| 687 | * copy into its own list, so we need to add that copy to the vnode's lock |
| 688 | * queue in the same place as the original (which will be deleted shortly |
| 689 | * after) |
| 690 | */ |
| 691 | static void afs_fl_copy_lock(struct file_lock *new, struct file_lock *fl) |
| 692 | { |
David Howells | 0fafdc9 | 2017-11-13 16:59:50 +0000 | [diff] [blame] | 693 | struct afs_vnode *vnode = AFS_FS_I(locks_inode(fl->fl_file)); |
| 694 | |
David Howells | e8d6c55 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 695 | _enter(""); |
| 696 | |
David Howells | 0fafdc9 | 2017-11-13 16:59:50 +0000 | [diff] [blame] | 697 | spin_lock(&vnode->lock); |
David Howells | e8d6c55 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 698 | list_add(&new->fl_u.afs.link, &fl->fl_u.afs.link); |
David Howells | 0fafdc9 | 2017-11-13 16:59:50 +0000 | [diff] [blame] | 699 | spin_unlock(&vnode->lock); |
David Howells | e8d6c55 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 700 | } |
| 701 | |
| 702 | /* |
| 703 | * need to remove this lock from the vnode queue when it's removed from the |
| 704 | * VFS's list |
| 705 | */ |
| 706 | static void afs_fl_release_private(struct file_lock *fl) |
| 707 | { |
David Howells | 0fafdc9 | 2017-11-13 16:59:50 +0000 | [diff] [blame] | 708 | struct afs_vnode *vnode = AFS_FS_I(locks_inode(fl->fl_file)); |
| 709 | |
David Howells | e8d6c55 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 710 | _enter(""); |
| 711 | |
David Howells | 0fafdc9 | 2017-11-13 16:59:50 +0000 | [diff] [blame] | 712 | spin_lock(&vnode->lock); |
| 713 | afs_dequeue_lock(vnode, fl); |
| 714 | _debug("state %u for %p", vnode->lock_state, vnode); |
| 715 | spin_unlock(&vnode->lock); |
David Howells | e8d6c55 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 716 | } |