Mark Fasheh | 8df08c8 | 2005-12-15 14:31:23 -0800 | [diff] [blame] | 1 | /* -*- mode: c; c-basic-offset: 8; -*- |
| 2 | * vim: noexpandtab sw=8 ts=8 sts=0: |
| 3 | * |
| 4 | * userdlm.c |
| 5 | * |
| 6 | * Code which implements the kernel side of a minimal userspace |
| 7 | * interface to our DLM. |
| 8 | * |
| 9 | * Many of the functions here are pared down versions of dlmglue.c |
| 10 | * functions. |
| 11 | * |
| 12 | * Copyright (C) 2003, 2004 Oracle. All rights reserved. |
| 13 | * |
| 14 | * This program is free software; you can redistribute it and/or |
| 15 | * modify it under the terms of the GNU General Public |
| 16 | * License as published by the Free Software Foundation; either |
| 17 | * version 2 of the License, or (at your option) any later version. |
| 18 | * |
| 19 | * This program is distributed in the hope that it will be useful, |
| 20 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 21 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 22 | * General Public License for more details. |
| 23 | * |
| 24 | * You should have received a copy of the GNU General Public |
| 25 | * License along with this program; if not, write to the |
| 26 | * Free Software Foundation, Inc., 59 Temple Place - Suite 330, |
| 27 | * Boston, MA 021110-1307, USA. |
| 28 | */ |
| 29 | |
Jeff Mahoney | aee93ac | 2006-01-09 12:36:40 -0500 | [diff] [blame] | 30 | #include <linux/signal.h> |
Mark Fasheh | 8df08c8 | 2005-12-15 14:31:23 -0800 | [diff] [blame] | 31 | |
| 32 | #include <linux/module.h> |
| 33 | #include <linux/fs.h> |
| 34 | #include <linux/types.h> |
| 35 | #include <linux/crc32.h> |
| 36 | |
| 37 | |
| 38 | #include "cluster/nodemanager.h" |
| 39 | #include "cluster/heartbeat.h" |
| 40 | #include "cluster/tcp.h" |
| 41 | |
| 42 | #include "dlmapi.h" |
| 43 | |
| 44 | #include "userdlm.h" |
| 45 | |
| 46 | #define MLOG_MASK_PREFIX ML_DLMFS |
| 47 | #include "cluster/masklog.h" |
| 48 | |
| 49 | static inline int user_check_wait_flag(struct user_lock_res *lockres, |
| 50 | int flag) |
| 51 | { |
| 52 | int ret; |
| 53 | |
| 54 | spin_lock(&lockres->l_lock); |
| 55 | ret = lockres->l_flags & flag; |
| 56 | spin_unlock(&lockres->l_lock); |
| 57 | |
| 58 | return ret; |
| 59 | } |
| 60 | |
| 61 | static inline void user_wait_on_busy_lock(struct user_lock_res *lockres) |
| 62 | |
| 63 | { |
| 64 | wait_event(lockres->l_event, |
| 65 | !user_check_wait_flag(lockres, USER_LOCK_BUSY)); |
| 66 | } |
| 67 | |
| 68 | static inline void user_wait_on_blocked_lock(struct user_lock_res *lockres) |
| 69 | |
| 70 | { |
| 71 | wait_event(lockres->l_event, |
| 72 | !user_check_wait_flag(lockres, USER_LOCK_BLOCKED)); |
| 73 | } |
| 74 | |
| 75 | /* I heart container_of... */ |
| 76 | static inline struct dlm_ctxt * |
| 77 | dlm_ctxt_from_user_lockres(struct user_lock_res *lockres) |
| 78 | { |
| 79 | struct dlmfs_inode_private *ip; |
| 80 | |
| 81 | ip = container_of(lockres, |
| 82 | struct dlmfs_inode_private, |
| 83 | ip_lockres); |
| 84 | return ip->ip_dlm; |
| 85 | } |
| 86 | |
| 87 | static struct inode * |
| 88 | user_dlm_inode_from_user_lockres(struct user_lock_res *lockres) |
| 89 | { |
| 90 | struct dlmfs_inode_private *ip; |
| 91 | |
| 92 | ip = container_of(lockres, |
| 93 | struct dlmfs_inode_private, |
| 94 | ip_lockres); |
| 95 | return &ip->ip_vfs_inode; |
| 96 | } |
| 97 | |
| 98 | static inline void user_recover_from_dlm_error(struct user_lock_res *lockres) |
| 99 | { |
| 100 | spin_lock(&lockres->l_lock); |
| 101 | lockres->l_flags &= ~USER_LOCK_BUSY; |
| 102 | spin_unlock(&lockres->l_lock); |
| 103 | } |
| 104 | |
| 105 | #define user_log_dlm_error(_func, _stat, _lockres) do { \ |
| 106 | mlog(ML_ERROR, "Dlm error \"%s\" while calling %s on " \ |
| 107 | "resource %s: %s\n", dlm_errname(_stat), _func, \ |
| 108 | _lockres->l_name, dlm_errmsg(_stat)); \ |
| 109 | } while (0) |
| 110 | |
| 111 | /* WARNING: This function lives in a world where the only three lock |
| 112 | * levels are EX, PR, and NL. It *will* have to be adjusted when more |
| 113 | * lock types are added. */ |
| 114 | static inline int user_highest_compat_lock_level(int level) |
| 115 | { |
| 116 | int new_level = LKM_EXMODE; |
| 117 | |
| 118 | if (level == LKM_EXMODE) |
| 119 | new_level = LKM_NLMODE; |
| 120 | else if (level == LKM_PRMODE) |
| 121 | new_level = LKM_PRMODE; |
| 122 | return new_level; |
| 123 | } |
| 124 | |
| 125 | static void user_ast(void *opaque) |
| 126 | { |
| 127 | struct user_lock_res *lockres = opaque; |
| 128 | struct dlm_lockstatus *lksb; |
| 129 | |
| 130 | mlog(0, "AST fired for lockres %s\n", lockres->l_name); |
| 131 | |
| 132 | spin_lock(&lockres->l_lock); |
| 133 | |
| 134 | lksb = &(lockres->l_lksb); |
| 135 | if (lksb->status != DLM_NORMAL) { |
| 136 | mlog(ML_ERROR, "lksb status value of %u on lockres %s\n", |
| 137 | lksb->status, lockres->l_name); |
| 138 | spin_unlock(&lockres->l_lock); |
| 139 | return; |
| 140 | } |
| 141 | |
Mark Fasheh | cc6eb72 | 2006-03-29 10:34:21 -0800 | [diff] [blame] | 142 | mlog_bug_on_msg(lockres->l_requested == LKM_IVMODE, |
| 143 | "Lockres %s, requested ivmode. flags 0x%x\n", |
| 144 | lockres->l_name, lockres->l_flags); |
| 145 | |
Mark Fasheh | 8df08c8 | 2005-12-15 14:31:23 -0800 | [diff] [blame] | 146 | /* we're downconverting. */ |
| 147 | if (lockres->l_requested < lockres->l_level) { |
| 148 | if (lockres->l_requested <= |
| 149 | user_highest_compat_lock_level(lockres->l_blocking)) { |
| 150 | lockres->l_blocking = LKM_NLMODE; |
| 151 | lockres->l_flags &= ~USER_LOCK_BLOCKED; |
| 152 | } |
| 153 | } |
| 154 | |
| 155 | lockres->l_level = lockres->l_requested; |
| 156 | lockres->l_requested = LKM_IVMODE; |
| 157 | lockres->l_flags |= USER_LOCK_ATTACHED; |
| 158 | lockres->l_flags &= ~USER_LOCK_BUSY; |
| 159 | |
| 160 | spin_unlock(&lockres->l_lock); |
| 161 | |
| 162 | wake_up(&lockres->l_event); |
| 163 | } |
| 164 | |
| 165 | static inline void user_dlm_grab_inode_ref(struct user_lock_res *lockres) |
| 166 | { |
| 167 | struct inode *inode; |
| 168 | inode = user_dlm_inode_from_user_lockres(lockres); |
| 169 | if (!igrab(inode)) |
| 170 | BUG(); |
| 171 | } |
| 172 | |
| 173 | static void user_dlm_unblock_lock(void *opaque); |
| 174 | |
| 175 | static void __user_dlm_queue_lockres(struct user_lock_res *lockres) |
| 176 | { |
| 177 | if (!(lockres->l_flags & USER_LOCK_QUEUED)) { |
| 178 | user_dlm_grab_inode_ref(lockres); |
| 179 | |
| 180 | INIT_WORK(&lockres->l_work, user_dlm_unblock_lock, |
| 181 | lockres); |
| 182 | |
| 183 | queue_work(user_dlm_worker, &lockres->l_work); |
| 184 | lockres->l_flags |= USER_LOCK_QUEUED; |
| 185 | } |
| 186 | } |
| 187 | |
| 188 | static void __user_dlm_cond_queue_lockres(struct user_lock_res *lockres) |
| 189 | { |
| 190 | int queue = 0; |
| 191 | |
| 192 | if (!(lockres->l_flags & USER_LOCK_BLOCKED)) |
| 193 | return; |
| 194 | |
| 195 | switch (lockres->l_blocking) { |
| 196 | case LKM_EXMODE: |
| 197 | if (!lockres->l_ex_holders && !lockres->l_ro_holders) |
| 198 | queue = 1; |
| 199 | break; |
| 200 | case LKM_PRMODE: |
| 201 | if (!lockres->l_ex_holders) |
| 202 | queue = 1; |
| 203 | break; |
| 204 | default: |
| 205 | BUG(); |
| 206 | } |
| 207 | |
| 208 | if (queue) |
| 209 | __user_dlm_queue_lockres(lockres); |
| 210 | } |
| 211 | |
| 212 | static void user_bast(void *opaque, int level) |
| 213 | { |
| 214 | struct user_lock_res *lockres = opaque; |
| 215 | |
| 216 | mlog(0, "Blocking AST fired for lockres %s. Blocking level %d\n", |
| 217 | lockres->l_name, level); |
| 218 | |
| 219 | spin_lock(&lockres->l_lock); |
| 220 | lockres->l_flags |= USER_LOCK_BLOCKED; |
| 221 | if (level > lockres->l_blocking) |
| 222 | lockres->l_blocking = level; |
| 223 | |
| 224 | __user_dlm_queue_lockres(lockres); |
| 225 | spin_unlock(&lockres->l_lock); |
| 226 | |
| 227 | wake_up(&lockres->l_event); |
| 228 | } |
| 229 | |
| 230 | static void user_unlock_ast(void *opaque, enum dlm_status status) |
| 231 | { |
| 232 | struct user_lock_res *lockres = opaque; |
| 233 | |
| 234 | mlog(0, "UNLOCK AST called on lock %s\n", lockres->l_name); |
| 235 | |
Mark Fasheh | f43e691 | 2006-03-29 18:24:12 -0800 | [diff] [blame] | 236 | if (status != DLM_NORMAL && status != DLM_CANCELGRANT) |
Mark Fasheh | 8df08c8 | 2005-12-15 14:31:23 -0800 | [diff] [blame] | 237 | mlog(ML_ERROR, "Dlm returns status %d\n", status); |
| 238 | |
| 239 | spin_lock(&lockres->l_lock); |
Mark Fasheh | 2cd9888 | 2006-03-29 16:49:13 -0800 | [diff] [blame] | 240 | /* The teardown flag gets set early during the unlock process, |
| 241 | * so test the cancel flag to make sure that this ast isn't |
| 242 | * for a concurrent cancel. */ |
| 243 | if (lockres->l_flags & USER_LOCK_IN_TEARDOWN |
| 244 | && !(lockres->l_flags & USER_LOCK_IN_CANCEL)) { |
Mark Fasheh | 8df08c8 | 2005-12-15 14:31:23 -0800 | [diff] [blame] | 245 | lockres->l_level = LKM_IVMODE; |
Mark Fasheh | 2cd9888 | 2006-03-29 16:49:13 -0800 | [diff] [blame] | 246 | } else if (status == DLM_CANCELGRANT) { |
Mark Fasheh | f43e691 | 2006-03-29 18:24:12 -0800 | [diff] [blame] | 247 | mlog(0, "Lock %s, cancel fails, flags 0x%x\n", |
| 248 | lockres->l_name, lockres->l_flags); |
| 249 | /* We tried to cancel a convert request, but it was |
| 250 | * already granted. Don't clear the busy flag - the |
| 251 | * ast should've done this already. */ |
| 252 | BUG_ON(!(lockres->l_flags & USER_LOCK_IN_CANCEL)); |
| 253 | lockres->l_flags &= ~USER_LOCK_IN_CANCEL; |
| 254 | goto out_noclear; |
| 255 | } else { |
| 256 | BUG_ON(!(lockres->l_flags & USER_LOCK_IN_CANCEL)); |
| 257 | /* Cancel succeeded, we want to re-queue */ |
| 258 | mlog(0, "Lock %s, cancel succeeds, flags 0x%x\n", |
| 259 | lockres->l_name, lockres->l_flags); |
Mark Fasheh | 8df08c8 | 2005-12-15 14:31:23 -0800 | [diff] [blame] | 260 | lockres->l_requested = LKM_IVMODE; /* cancel an |
| 261 | * upconvert |
| 262 | * request. */ |
| 263 | lockres->l_flags &= ~USER_LOCK_IN_CANCEL; |
| 264 | /* we want the unblock thread to look at it again |
| 265 | * now. */ |
Mark Fasheh | f43e691 | 2006-03-29 18:24:12 -0800 | [diff] [blame] | 266 | if (lockres->l_flags & USER_LOCK_BLOCKED) |
| 267 | __user_dlm_queue_lockres(lockres); |
Mark Fasheh | 8df08c8 | 2005-12-15 14:31:23 -0800 | [diff] [blame] | 268 | } |
| 269 | |
| 270 | lockres->l_flags &= ~USER_LOCK_BUSY; |
Mark Fasheh | f43e691 | 2006-03-29 18:24:12 -0800 | [diff] [blame] | 271 | out_noclear: |
Mark Fasheh | 8df08c8 | 2005-12-15 14:31:23 -0800 | [diff] [blame] | 272 | spin_unlock(&lockres->l_lock); |
| 273 | |
| 274 | wake_up(&lockres->l_event); |
| 275 | } |
| 276 | |
| 277 | static inline void user_dlm_drop_inode_ref(struct user_lock_res *lockres) |
| 278 | { |
| 279 | struct inode *inode; |
| 280 | inode = user_dlm_inode_from_user_lockres(lockres); |
| 281 | iput(inode); |
| 282 | } |
| 283 | |
| 284 | static void user_dlm_unblock_lock(void *opaque) |
| 285 | { |
| 286 | int new_level, status; |
| 287 | struct user_lock_res *lockres = (struct user_lock_res *) opaque; |
| 288 | struct dlm_ctxt *dlm = dlm_ctxt_from_user_lockres(lockres); |
| 289 | |
| 290 | mlog(0, "processing lockres %s\n", lockres->l_name); |
| 291 | |
| 292 | spin_lock(&lockres->l_lock); |
| 293 | |
Mark Fasheh | 1f7bc82 | 2006-03-29 10:33:35 -0800 | [diff] [blame] | 294 | mlog_bug_on_msg(!(lockres->l_flags & USER_LOCK_QUEUED), |
| 295 | "Lockres %s, flags 0x%x\n", |
| 296 | lockres->l_name, lockres->l_flags); |
Mark Fasheh | 8df08c8 | 2005-12-15 14:31:23 -0800 | [diff] [blame] | 297 | |
Mark Fasheh | 1f7bc82 | 2006-03-29 10:33:35 -0800 | [diff] [blame] | 298 | /* notice that we don't clear USER_LOCK_BLOCKED here. If it's |
| 299 | * set, we want user_ast clear it. */ |
Mark Fasheh | 8df08c8 | 2005-12-15 14:31:23 -0800 | [diff] [blame] | 300 | lockres->l_flags &= ~USER_LOCK_QUEUED; |
| 301 | |
Mark Fasheh | 1f7bc82 | 2006-03-29 10:33:35 -0800 | [diff] [blame] | 302 | /* It's valid to get here and no longer be blocked - if we get |
| 303 | * several basts in a row, we might be queued by the first |
| 304 | * one, the unblock thread might run and clear the queued |
| 305 | * flag, and finally we might get another bast which re-queues |
| 306 | * us before our ast for the downconvert is called. */ |
| 307 | if (!(lockres->l_flags & USER_LOCK_BLOCKED)) { |
| 308 | mlog(0, "Lockres %s, flags 0x%x: queued but not blocking\n", |
| 309 | lockres->l_name, lockres->l_flags); |
| 310 | spin_unlock(&lockres->l_lock); |
| 311 | goto drop_ref; |
| 312 | } |
| 313 | |
Mark Fasheh | 8df08c8 | 2005-12-15 14:31:23 -0800 | [diff] [blame] | 314 | if (lockres->l_flags & USER_LOCK_IN_TEARDOWN) { |
| 315 | mlog(0, "lock is in teardown so we do nothing\n"); |
| 316 | spin_unlock(&lockres->l_lock); |
| 317 | goto drop_ref; |
| 318 | } |
| 319 | |
| 320 | if (lockres->l_flags & USER_LOCK_BUSY) { |
Mark Fasheh | f43e691 | 2006-03-29 18:24:12 -0800 | [diff] [blame] | 321 | mlog(0, "Cancel lock %s, flags 0x%x\n", |
| 322 | lockres->l_name, lockres->l_flags); |
| 323 | |
Mark Fasheh | 8df08c8 | 2005-12-15 14:31:23 -0800 | [diff] [blame] | 324 | if (lockres->l_flags & USER_LOCK_IN_CANCEL) { |
| 325 | spin_unlock(&lockres->l_lock); |
| 326 | goto drop_ref; |
| 327 | } |
| 328 | |
| 329 | lockres->l_flags |= USER_LOCK_IN_CANCEL; |
| 330 | spin_unlock(&lockres->l_lock); |
| 331 | |
| 332 | status = dlmunlock(dlm, |
| 333 | &lockres->l_lksb, |
| 334 | LKM_CANCEL, |
| 335 | user_unlock_ast, |
| 336 | lockres); |
Mark Fasheh | f43e691 | 2006-03-29 18:24:12 -0800 | [diff] [blame] | 337 | if (status != DLM_NORMAL) |
Mark Fasheh | 8df08c8 | 2005-12-15 14:31:23 -0800 | [diff] [blame] | 338 | user_log_dlm_error("dlmunlock", status, lockres); |
| 339 | goto drop_ref; |
| 340 | } |
| 341 | |
| 342 | /* If there are still incompat holders, we can exit safely |
| 343 | * without worrying about re-queueing this lock as that will |
| 344 | * happen on the last call to user_cluster_unlock. */ |
| 345 | if ((lockres->l_blocking == LKM_EXMODE) |
| 346 | && (lockres->l_ex_holders || lockres->l_ro_holders)) { |
| 347 | spin_unlock(&lockres->l_lock); |
| 348 | mlog(0, "can't downconvert for ex: ro = %u, ex = %u\n", |
| 349 | lockres->l_ro_holders, lockres->l_ex_holders); |
| 350 | goto drop_ref; |
| 351 | } |
| 352 | |
| 353 | if ((lockres->l_blocking == LKM_PRMODE) |
| 354 | && lockres->l_ex_holders) { |
| 355 | spin_unlock(&lockres->l_lock); |
| 356 | mlog(0, "can't downconvert for pr: ex = %u\n", |
| 357 | lockres->l_ex_holders); |
| 358 | goto drop_ref; |
| 359 | } |
| 360 | |
| 361 | /* yay, we can downconvert now. */ |
| 362 | new_level = user_highest_compat_lock_level(lockres->l_blocking); |
| 363 | lockres->l_requested = new_level; |
| 364 | lockres->l_flags |= USER_LOCK_BUSY; |
| 365 | mlog(0, "Downconvert lock from %d to %d\n", |
| 366 | lockres->l_level, new_level); |
| 367 | spin_unlock(&lockres->l_lock); |
| 368 | |
| 369 | /* need lock downconvert request now... */ |
| 370 | status = dlmlock(dlm, |
| 371 | new_level, |
| 372 | &lockres->l_lksb, |
| 373 | LKM_CONVERT|LKM_VALBLK, |
| 374 | lockres->l_name, |
| 375 | user_ast, |
| 376 | lockres, |
| 377 | user_bast); |
| 378 | if (status != DLM_NORMAL) { |
| 379 | user_log_dlm_error("dlmlock", status, lockres); |
| 380 | user_recover_from_dlm_error(lockres); |
| 381 | } |
| 382 | |
| 383 | drop_ref: |
| 384 | user_dlm_drop_inode_ref(lockres); |
| 385 | } |
| 386 | |
| 387 | static inline void user_dlm_inc_holders(struct user_lock_res *lockres, |
| 388 | int level) |
| 389 | { |
| 390 | switch(level) { |
| 391 | case LKM_EXMODE: |
| 392 | lockres->l_ex_holders++; |
| 393 | break; |
| 394 | case LKM_PRMODE: |
| 395 | lockres->l_ro_holders++; |
| 396 | break; |
| 397 | default: |
| 398 | BUG(); |
| 399 | } |
| 400 | } |
| 401 | |
| 402 | /* predict what lock level we'll be dropping down to on behalf |
| 403 | * of another node, and return true if the currently wanted |
| 404 | * level will be compatible with it. */ |
| 405 | static inline int |
| 406 | user_may_continue_on_blocked_lock(struct user_lock_res *lockres, |
| 407 | int wanted) |
| 408 | { |
| 409 | BUG_ON(!(lockres->l_flags & USER_LOCK_BLOCKED)); |
| 410 | |
| 411 | return wanted <= user_highest_compat_lock_level(lockres->l_blocking); |
| 412 | } |
| 413 | |
| 414 | int user_dlm_cluster_lock(struct user_lock_res *lockres, |
| 415 | int level, |
| 416 | int lkm_flags) |
| 417 | { |
| 418 | int status, local_flags; |
| 419 | struct dlm_ctxt *dlm = dlm_ctxt_from_user_lockres(lockres); |
| 420 | |
| 421 | if (level != LKM_EXMODE && |
| 422 | level != LKM_PRMODE) { |
| 423 | mlog(ML_ERROR, "lockres %s: invalid request!\n", |
| 424 | lockres->l_name); |
| 425 | status = -EINVAL; |
| 426 | goto bail; |
| 427 | } |
| 428 | |
| 429 | mlog(0, "lockres %s: asking for %s lock, passed flags = 0x%x\n", |
| 430 | lockres->l_name, |
| 431 | (level == LKM_EXMODE) ? "LKM_EXMODE" : "LKM_PRMODE", |
| 432 | lkm_flags); |
| 433 | |
| 434 | again: |
| 435 | if (signal_pending(current)) { |
| 436 | status = -ERESTARTSYS; |
| 437 | goto bail; |
| 438 | } |
| 439 | |
| 440 | spin_lock(&lockres->l_lock); |
| 441 | |
| 442 | /* We only compare against the currently granted level |
| 443 | * here. If the lock is blocked waiting on a downconvert, |
| 444 | * we'll get caught below. */ |
| 445 | if ((lockres->l_flags & USER_LOCK_BUSY) && |
| 446 | (level > lockres->l_level)) { |
| 447 | /* is someone sitting in dlm_lock? If so, wait on |
| 448 | * them. */ |
| 449 | spin_unlock(&lockres->l_lock); |
| 450 | |
| 451 | user_wait_on_busy_lock(lockres); |
| 452 | goto again; |
| 453 | } |
| 454 | |
| 455 | if ((lockres->l_flags & USER_LOCK_BLOCKED) && |
| 456 | (!user_may_continue_on_blocked_lock(lockres, level))) { |
| 457 | /* is the lock is currently blocked on behalf of |
| 458 | * another node */ |
| 459 | spin_unlock(&lockres->l_lock); |
| 460 | |
| 461 | user_wait_on_blocked_lock(lockres); |
| 462 | goto again; |
| 463 | } |
| 464 | |
| 465 | if (level > lockres->l_level) { |
| 466 | local_flags = lkm_flags | LKM_VALBLK; |
| 467 | if (lockres->l_level != LKM_IVMODE) |
| 468 | local_flags |= LKM_CONVERT; |
| 469 | |
| 470 | lockres->l_requested = level; |
| 471 | lockres->l_flags |= USER_LOCK_BUSY; |
| 472 | spin_unlock(&lockres->l_lock); |
| 473 | |
| 474 | BUG_ON(level == LKM_IVMODE); |
| 475 | BUG_ON(level == LKM_NLMODE); |
| 476 | |
| 477 | mlog(0, "lock %s, get lock from %d to level = %d\n", |
| 478 | lockres->l_name, lockres->l_level, level); |
| 479 | |
| 480 | /* call dlm_lock to upgrade lock now */ |
| 481 | status = dlmlock(dlm, |
| 482 | level, |
| 483 | &lockres->l_lksb, |
| 484 | local_flags, |
| 485 | lockres->l_name, |
| 486 | user_ast, |
| 487 | lockres, |
| 488 | user_bast); |
| 489 | if (status != DLM_NORMAL) { |
| 490 | if ((lkm_flags & LKM_NOQUEUE) && |
| 491 | (status == DLM_NOTQUEUED)) |
| 492 | status = -EAGAIN; |
| 493 | else { |
| 494 | user_log_dlm_error("dlmlock", status, lockres); |
| 495 | status = -EINVAL; |
| 496 | } |
| 497 | user_recover_from_dlm_error(lockres); |
| 498 | goto bail; |
| 499 | } |
| 500 | |
| 501 | mlog(0, "lock %s, successfull return from dlmlock\n", |
| 502 | lockres->l_name); |
| 503 | |
| 504 | user_wait_on_busy_lock(lockres); |
| 505 | goto again; |
| 506 | } |
| 507 | |
| 508 | user_dlm_inc_holders(lockres, level); |
| 509 | spin_unlock(&lockres->l_lock); |
| 510 | |
| 511 | mlog(0, "lockres %s: Got %s lock!\n", lockres->l_name, |
| 512 | (level == LKM_EXMODE) ? "LKM_EXMODE" : "LKM_PRMODE"); |
| 513 | |
| 514 | status = 0; |
| 515 | bail: |
| 516 | return status; |
| 517 | } |
| 518 | |
| 519 | static inline void user_dlm_dec_holders(struct user_lock_res *lockres, |
| 520 | int level) |
| 521 | { |
| 522 | switch(level) { |
| 523 | case LKM_EXMODE: |
| 524 | BUG_ON(!lockres->l_ex_holders); |
| 525 | lockres->l_ex_holders--; |
| 526 | break; |
| 527 | case LKM_PRMODE: |
| 528 | BUG_ON(!lockres->l_ro_holders); |
| 529 | lockres->l_ro_holders--; |
| 530 | break; |
| 531 | default: |
| 532 | BUG(); |
| 533 | } |
| 534 | } |
| 535 | |
| 536 | void user_dlm_cluster_unlock(struct user_lock_res *lockres, |
| 537 | int level) |
| 538 | { |
| 539 | if (level != LKM_EXMODE && |
| 540 | level != LKM_PRMODE) { |
| 541 | mlog(ML_ERROR, "lockres %s: invalid request!\n", lockres->l_name); |
| 542 | return; |
| 543 | } |
| 544 | |
| 545 | mlog(0, "lockres %s: dropping %s lock\n", lockres->l_name, |
| 546 | (level == LKM_EXMODE) ? "LKM_EXMODE" : "LKM_PRMODE"); |
| 547 | |
| 548 | spin_lock(&lockres->l_lock); |
| 549 | user_dlm_dec_holders(lockres, level); |
| 550 | __user_dlm_cond_queue_lockres(lockres); |
| 551 | spin_unlock(&lockres->l_lock); |
| 552 | } |
| 553 | |
| 554 | void user_dlm_write_lvb(struct inode *inode, |
| 555 | const char *val, |
| 556 | unsigned int len) |
| 557 | { |
| 558 | struct user_lock_res *lockres = &DLMFS_I(inode)->ip_lockres; |
| 559 | char *lvb = lockres->l_lksb.lvb; |
| 560 | |
| 561 | BUG_ON(len > DLM_LVB_LEN); |
| 562 | |
| 563 | spin_lock(&lockres->l_lock); |
| 564 | |
| 565 | BUG_ON(lockres->l_level < LKM_EXMODE); |
| 566 | memcpy(lvb, val, len); |
| 567 | |
| 568 | spin_unlock(&lockres->l_lock); |
| 569 | } |
| 570 | |
| 571 | void user_dlm_read_lvb(struct inode *inode, |
| 572 | char *val, |
| 573 | unsigned int len) |
| 574 | { |
| 575 | struct user_lock_res *lockres = &DLMFS_I(inode)->ip_lockres; |
| 576 | char *lvb = lockres->l_lksb.lvb; |
| 577 | |
| 578 | BUG_ON(len > DLM_LVB_LEN); |
| 579 | |
| 580 | spin_lock(&lockres->l_lock); |
| 581 | |
| 582 | BUG_ON(lockres->l_level < LKM_PRMODE); |
| 583 | memcpy(val, lvb, len); |
| 584 | |
| 585 | spin_unlock(&lockres->l_lock); |
| 586 | } |
| 587 | |
| 588 | void user_dlm_lock_res_init(struct user_lock_res *lockres, |
| 589 | struct dentry *dentry) |
| 590 | { |
| 591 | memset(lockres, 0, sizeof(*lockres)); |
| 592 | |
| 593 | spin_lock_init(&lockres->l_lock); |
| 594 | init_waitqueue_head(&lockres->l_event); |
| 595 | lockres->l_level = LKM_IVMODE; |
| 596 | lockres->l_requested = LKM_IVMODE; |
| 597 | lockres->l_blocking = LKM_IVMODE; |
| 598 | |
| 599 | /* should have been checked before getting here. */ |
| 600 | BUG_ON(dentry->d_name.len >= USER_DLM_LOCK_ID_MAX_LEN); |
| 601 | |
| 602 | memcpy(lockres->l_name, |
| 603 | dentry->d_name.name, |
| 604 | dentry->d_name.len); |
| 605 | } |
| 606 | |
| 607 | int user_dlm_destroy_lock(struct user_lock_res *lockres) |
| 608 | { |
| 609 | int status = -EBUSY; |
| 610 | struct dlm_ctxt *dlm = dlm_ctxt_from_user_lockres(lockres); |
| 611 | |
| 612 | mlog(0, "asked to destroy %s\n", lockres->l_name); |
| 613 | |
| 614 | spin_lock(&lockres->l_lock); |
Mark Fasheh | 2cd9888 | 2006-03-29 16:49:13 -0800 | [diff] [blame] | 615 | if (lockres->l_flags & USER_LOCK_IN_TEARDOWN) { |
| 616 | mlog(0, "Lock is already torn down\n"); |
| 617 | spin_unlock(&lockres->l_lock); |
| 618 | return 0; |
| 619 | } |
| 620 | |
| 621 | lockres->l_flags |= USER_LOCK_IN_TEARDOWN; |
| 622 | |
Mark Fasheh | 8df08c8 | 2005-12-15 14:31:23 -0800 | [diff] [blame] | 623 | while (lockres->l_flags & USER_LOCK_BUSY) { |
| 624 | spin_unlock(&lockres->l_lock); |
| 625 | |
| 626 | mlog(0, "lock %s is busy\n", lockres->l_name); |
| 627 | |
| 628 | user_wait_on_busy_lock(lockres); |
| 629 | |
| 630 | spin_lock(&lockres->l_lock); |
| 631 | } |
| 632 | |
| 633 | if (lockres->l_ro_holders || lockres->l_ex_holders) { |
| 634 | spin_unlock(&lockres->l_lock); |
| 635 | mlog(0, "lock %s has holders\n", lockres->l_name); |
| 636 | goto bail; |
| 637 | } |
| 638 | |
| 639 | status = 0; |
| 640 | if (!(lockres->l_flags & USER_LOCK_ATTACHED)) { |
| 641 | spin_unlock(&lockres->l_lock); |
| 642 | mlog(0, "lock %s is not attached\n", lockres->l_name); |
| 643 | goto bail; |
| 644 | } |
| 645 | |
| 646 | lockres->l_flags &= ~USER_LOCK_ATTACHED; |
| 647 | lockres->l_flags |= USER_LOCK_BUSY; |
Mark Fasheh | 8df08c8 | 2005-12-15 14:31:23 -0800 | [diff] [blame] | 648 | spin_unlock(&lockres->l_lock); |
| 649 | |
| 650 | mlog(0, "unlocking lockres %s\n", lockres->l_name); |
| 651 | status = dlmunlock(dlm, |
| 652 | &lockres->l_lksb, |
| 653 | LKM_VALBLK, |
| 654 | user_unlock_ast, |
| 655 | lockres); |
| 656 | if (status != DLM_NORMAL) { |
| 657 | user_log_dlm_error("dlmunlock", status, lockres); |
| 658 | status = -EINVAL; |
| 659 | goto bail; |
| 660 | } |
| 661 | |
| 662 | user_wait_on_busy_lock(lockres); |
| 663 | |
| 664 | status = 0; |
| 665 | bail: |
| 666 | return status; |
| 667 | } |
| 668 | |
| 669 | struct dlm_ctxt *user_dlm_register_context(struct qstr *name) |
| 670 | { |
| 671 | struct dlm_ctxt *dlm; |
| 672 | u32 dlm_key; |
| 673 | char *domain; |
| 674 | |
| 675 | domain = kmalloc(name->len + 1, GFP_KERNEL); |
| 676 | if (!domain) { |
| 677 | mlog_errno(-ENOMEM); |
| 678 | return ERR_PTR(-ENOMEM); |
| 679 | } |
| 680 | |
| 681 | dlm_key = crc32_le(0, name->name, name->len); |
| 682 | |
| 683 | snprintf(domain, name->len + 1, "%.*s", name->len, name->name); |
| 684 | |
| 685 | dlm = dlm_register_domain(domain, dlm_key); |
| 686 | if (IS_ERR(dlm)) |
| 687 | mlog_errno(PTR_ERR(dlm)); |
| 688 | |
| 689 | kfree(domain); |
| 690 | return dlm; |
| 691 | } |
| 692 | |
| 693 | void user_dlm_unregister_context(struct dlm_ctxt *dlm) |
| 694 | { |
| 695 | dlm_unregister_domain(dlm); |
| 696 | } |