1 /* 2 * Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved. 3 * Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved. 4 * 5 * This copyrighted material is made available to anyone wishing to use, 6 * modify, copy, or redistribute it subject to the terms and conditions 7 * of the GNU General Public License version 2. 8 */ 9 10 #include <linux/sched.h> 11 #include <linux/slab.h> 12 #include <linux/spinlock.h> 13 #include <linux/buffer_head.h> 14 #include <linux/delay.h> 15 #include <linux/sort.h> 16 #include <linux/jhash.h> 17 #include <linux/kallsyms.h> 18 #include <linux/gfs2_ondisk.h> 19 #include <linux/list.h> 20 #include <linux/wait.h> 21 #include <linux/module.h> 22 #include <asm/uaccess.h> 23 #include <linux/seq_file.h> 24 #include <linux/debugfs.h> 25 #include <linux/kthread.h> 26 #include <linux/freezer.h> 27 #include <linux/workqueue.h> 28 #include <linux/jiffies.h> 29 #include <linux/rcupdate.h> 30 #include <linux/rculist_bl.h> 31 #include <linux/bit_spinlock.h> 32 #include <linux/percpu.h> 33 #include <linux/list_sort.h> 34 #include <linux/lockref.h> 35 36 #include "gfs2.h" 37 #include "incore.h" 38 #include "glock.h" 39 #include "glops.h" 40 #include "inode.h" 41 #include "lops.h" 42 #include "meta_io.h" 43 #include "quota.h" 44 #include "super.h" 45 #include "util.h" 46 #include "bmap.h" 47 #define CREATE_TRACE_POINTS 48 #include "trace_gfs2.h" 49 50 struct gfs2_glock_iter { 51 int hash; /* hash bucket index */ 52 unsigned nhash; /* Index within current bucket */ 53 struct gfs2_sbd *sdp; /* incore superblock */ 54 struct gfs2_glock *gl; /* current glock struct */ 55 loff_t last_pos; /* last position */ 56 }; 57 58 typedef void (*glock_examiner) (struct gfs2_glock * gl); 59 60 static void do_xmote(struct gfs2_glock *gl, struct gfs2_holder *gh, unsigned int target); 61 62 static struct dentry *gfs2_root; 63 static struct workqueue_struct *glock_workqueue; 64 struct workqueue_struct *gfs2_delete_workqueue; 65 static LIST_HEAD(lru_list); 66 static atomic_t lru_count = ATOMIC_INIT(0); 67 static DEFINE_SPINLOCK(lru_lock); 68 69 #define GFS2_GL_HASH_SHIFT 15 70 #define GFS2_GL_HASH_SIZE (1 << GFS2_GL_HASH_SHIFT) 71 #define GFS2_GL_HASH_MASK (GFS2_GL_HASH_SIZE - 1) 72 73 static struct hlist_bl_head gl_hash_table[GFS2_GL_HASH_SIZE]; 74 static struct dentry *gfs2_root; 75 76 /** 77 * gl_hash() - Turn glock number into hash bucket number 78 * @lock: The glock number 79 * 80 * Returns: The number of the corresponding hash bucket 81 */ 82 83 static unsigned int gl_hash(const struct gfs2_sbd *sdp, 84 const struct lm_lockname *name) 85 { 86 unsigned int h; 87 88 h = jhash(&name->ln_number, sizeof(u64), 0); 89 h = jhash(&name->ln_type, sizeof(unsigned int), h); 90 h = jhash(&sdp, sizeof(struct gfs2_sbd *), h); 91 h &= GFS2_GL_HASH_MASK; 92 93 return h; 94 } 95 96 static inline void spin_lock_bucket(unsigned int hash) 97 { 98 hlist_bl_lock(&gl_hash_table[hash]); 99 } 100 101 static inline void spin_unlock_bucket(unsigned int hash) 102 { 103 hlist_bl_unlock(&gl_hash_table[hash]); 104 } 105 106 static void gfs2_glock_dealloc(struct rcu_head *rcu) 107 { 108 struct gfs2_glock *gl = container_of(rcu, struct gfs2_glock, gl_rcu); 109 110 if (gl->gl_ops->go_flags & GLOF_ASPACE) { 111 kmem_cache_free(gfs2_glock_aspace_cachep, gl); 112 } else { 113 kfree(gl->gl_lksb.sb_lvbptr); 114 kmem_cache_free(gfs2_glock_cachep, gl); 115 } 116 } 117 118 void gfs2_glock_free(struct gfs2_glock *gl) 119 { 120 struct gfs2_sbd *sdp = gl->gl_sbd; 121 122 call_rcu(&gl->gl_rcu, gfs2_glock_dealloc); 123 if (atomic_dec_and_test(&sdp->sd_glock_disposal)) 124 wake_up(&sdp->sd_glock_wait); 125 } 126 127 /** 128 * gfs2_glock_hold() - increment reference count on glock 129 * @gl: The glock to hold 130 * 131 */ 132 133 static void gfs2_glock_hold(struct gfs2_glock *gl) 134 { 135 GLOCK_BUG_ON(gl, __lockref_is_dead(&gl->gl_lockref)); 136 lockref_get(&gl->gl_lockref); 137 } 138 139 /** 140 * demote_ok - Check to see if it's ok to unlock a glock 141 * @gl: the glock 142 * 143 * Returns: 1 if it's ok 144 */ 145 146 static int demote_ok(const struct gfs2_glock *gl) 147 { 148 const struct gfs2_glock_operations *glops = gl->gl_ops; 149 150 if (gl->gl_state == LM_ST_UNLOCKED) 151 return 0; 152 if (!list_empty(&gl->gl_holders)) 153 return 0; 154 if (glops->go_demote_ok) 155 return glops->go_demote_ok(gl); 156 return 1; 157 } 158 159 160 void gfs2_glock_add_to_lru(struct gfs2_glock *gl) 161 { 162 spin_lock(&lru_lock); 163 164 if (!list_empty(&gl->gl_lru)) 165 list_del_init(&gl->gl_lru); 166 else 167 atomic_inc(&lru_count); 168 169 list_add_tail(&gl->gl_lru, &lru_list); 170 set_bit(GLF_LRU, &gl->gl_flags); 171 spin_unlock(&lru_lock); 172 } 173 174 static void __gfs2_glock_remove_from_lru(struct gfs2_glock *gl) 175 { 176 if (!list_empty(&gl->gl_lru)) { 177 list_del_init(&gl->gl_lru); 178 atomic_dec(&lru_count); 179 clear_bit(GLF_LRU, &gl->gl_flags); 180 } 181 } 182 183 static void gfs2_glock_remove_from_lru(struct gfs2_glock *gl) 184 { 185 spin_lock(&lru_lock); 186 __gfs2_glock_remove_from_lru(gl); 187 spin_unlock(&lru_lock); 188 } 189 190 /** 191 * gfs2_glock_put() - Decrement reference count on glock 192 * @gl: The glock to put 193 * 194 */ 195 196 void gfs2_glock_put(struct gfs2_glock *gl) 197 { 198 struct gfs2_sbd *sdp = gl->gl_sbd; 199 struct address_space *mapping = gfs2_glock2aspace(gl); 200 201 if (lockref_put_or_lock(&gl->gl_lockref)) 202 return; 203 204 lockref_mark_dead(&gl->gl_lockref); 205 206 spin_lock(&lru_lock); 207 __gfs2_glock_remove_from_lru(gl); 208 spin_unlock(&lru_lock); 209 spin_unlock(&gl->gl_lockref.lock); 210 spin_lock_bucket(gl->gl_hash); 211 hlist_bl_del_rcu(&gl->gl_list); 212 spin_unlock_bucket(gl->gl_hash); 213 GLOCK_BUG_ON(gl, !list_empty(&gl->gl_holders)); 214 GLOCK_BUG_ON(gl, mapping && mapping->nrpages); 215 trace_gfs2_glock_put(gl); 216 sdp->sd_lockstruct.ls_ops->lm_put_lock(gl); 217 } 218 219 /** 220 * search_bucket() - Find struct gfs2_glock by lock number 221 * @bucket: the bucket to search 222 * @name: The lock name 223 * 224 * Returns: NULL, or the struct gfs2_glock with the requested number 225 */ 226 227 static struct gfs2_glock *search_bucket(unsigned int hash, 228 const struct gfs2_sbd *sdp, 229 const struct lm_lockname *name) 230 { 231 struct gfs2_glock *gl; 232 struct hlist_bl_node *h; 233 234 hlist_bl_for_each_entry_rcu(gl, h, &gl_hash_table[hash], gl_list) { 235 if (!lm_name_equal(&gl->gl_name, name)) 236 continue; 237 if (gl->gl_sbd != sdp) 238 continue; 239 if (lockref_get_not_dead(&gl->gl_lockref)) 240 return gl; 241 } 242 243 return NULL; 244 } 245 246 /** 247 * may_grant - check if its ok to grant a new lock 248 * @gl: The glock 249 * @gh: The lock request which we wish to grant 250 * 251 * Returns: true if its ok to grant the lock 252 */ 253 254 static inline int may_grant(const struct gfs2_glock *gl, const struct gfs2_holder *gh) 255 { 256 const struct gfs2_holder *gh_head = list_entry(gl->gl_holders.next, const struct gfs2_holder, gh_list); 257 if ((gh->gh_state == LM_ST_EXCLUSIVE || 258 gh_head->gh_state == LM_ST_EXCLUSIVE) && gh != gh_head) 259 return 0; 260 if (gl->gl_state == gh->gh_state) 261 return 1; 262 if (gh->gh_flags & GL_EXACT) 263 return 0; 264 if (gl->gl_state == LM_ST_EXCLUSIVE) { 265 if (gh->gh_state == LM_ST_SHARED && gh_head->gh_state == LM_ST_SHARED) 266 return 1; 267 if (gh->gh_state == LM_ST_DEFERRED && gh_head->gh_state == LM_ST_DEFERRED) 268 return 1; 269 } 270 if (gl->gl_state != LM_ST_UNLOCKED && (gh->gh_flags & LM_FLAG_ANY)) 271 return 1; 272 return 0; 273 } 274 275 static void gfs2_holder_wake(struct gfs2_holder *gh) 276 { 277 clear_bit(HIF_WAIT, &gh->gh_iflags); 278 smp_mb__after_clear_bit(); 279 wake_up_bit(&gh->gh_iflags, HIF_WAIT); 280 } 281 282 /** 283 * do_error - Something unexpected has happened during a lock request 284 * 285 */ 286 287 static inline void do_error(struct gfs2_glock *gl, const int ret) 288 { 289 struct gfs2_holder *gh, *tmp; 290 291 list_for_each_entry_safe(gh, tmp, &gl->gl_holders, gh_list) { 292 if (test_bit(HIF_HOLDER, &gh->gh_iflags)) 293 continue; 294 if (ret & LM_OUT_ERROR) 295 gh->gh_error = -EIO; 296 else if (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)) 297 gh->gh_error = GLR_TRYFAILED; 298 else 299 continue; 300 list_del_init(&gh->gh_list); 301 trace_gfs2_glock_queue(gh, 0); 302 gfs2_holder_wake(gh); 303 } 304 } 305 306 /** 307 * do_promote - promote as many requests as possible on the current queue 308 * @gl: The glock 309 * 310 * Returns: 1 if there is a blocked holder at the head of the list, or 2 311 * if a type specific operation is underway. 312 */ 313 314 static int do_promote(struct gfs2_glock *gl) 315 __releases(&gl->gl_spin) 316 __acquires(&gl->gl_spin) 317 { 318 const struct gfs2_glock_operations *glops = gl->gl_ops; 319 struct gfs2_holder *gh, *tmp; 320 int ret; 321 322 restart: 323 list_for_each_entry_safe(gh, tmp, &gl->gl_holders, gh_list) { 324 if (test_bit(HIF_HOLDER, &gh->gh_iflags)) 325 continue; 326 if (may_grant(gl, gh)) { 327 if (gh->gh_list.prev == &gl->gl_holders && 328 glops->go_lock) { 329 spin_unlock(&gl->gl_spin); 330 /* FIXME: eliminate this eventually */ 331 ret = glops->go_lock(gh); 332 spin_lock(&gl->gl_spin); 333 if (ret) { 334 if (ret == 1) 335 return 2; 336 gh->gh_error = ret; 337 list_del_init(&gh->gh_list); 338 trace_gfs2_glock_queue(gh, 0); 339 gfs2_holder_wake(gh); 340 goto restart; 341 } 342 set_bit(HIF_HOLDER, &gh->gh_iflags); 343 trace_gfs2_promote(gh, 1); 344 gfs2_holder_wake(gh); 345 goto restart; 346 } 347 set_bit(HIF_HOLDER, &gh->gh_iflags); 348 trace_gfs2_promote(gh, 0); 349 gfs2_holder_wake(gh); 350 continue; 351 } 352 if (gh->gh_list.prev == &gl->gl_holders) 353 return 1; 354 do_error(gl, 0); 355 break; 356 } 357 return 0; 358 } 359 360 /** 361 * find_first_waiter - find the first gh that's waiting for the glock 362 * @gl: the glock 363 */ 364 365 static inline struct gfs2_holder *find_first_waiter(const struct gfs2_glock *gl) 366 { 367 struct gfs2_holder *gh; 368 369 list_for_each_entry(gh, &gl->gl_holders, gh_list) { 370 if (!test_bit(HIF_HOLDER, &gh->gh_iflags)) 371 return gh; 372 } 373 return NULL; 374 } 375 376 /** 377 * state_change - record that the glock is now in a different state 378 * @gl: the glock 379 * @new_state the new state 380 * 381 */ 382 383 static void state_change(struct gfs2_glock *gl, unsigned int new_state) 384 { 385 int held1, held2; 386 387 held1 = (gl->gl_state != LM_ST_UNLOCKED); 388 held2 = (new_state != LM_ST_UNLOCKED); 389 390 if (held1 != held2) { 391 GLOCK_BUG_ON(gl, __lockref_is_dead(&gl->gl_lockref)); 392 if (held2) 393 gl->gl_lockref.count++; 394 else 395 gl->gl_lockref.count--; 396 } 397 if (held1 && held2 && list_empty(&gl->gl_holders)) 398 clear_bit(GLF_QUEUED, &gl->gl_flags); 399 400 if (new_state != gl->gl_target) 401 /* shorten our minimum hold time */ 402 gl->gl_hold_time = max(gl->gl_hold_time - GL_GLOCK_HOLD_DECR, 403 GL_GLOCK_MIN_HOLD); 404 gl->gl_state = new_state; 405 gl->gl_tchange = jiffies; 406 } 407 408 static void gfs2_demote_wake(struct gfs2_glock *gl) 409 { 410 gl->gl_demote_state = LM_ST_EXCLUSIVE; 411 clear_bit(GLF_DEMOTE, &gl->gl_flags); 412 smp_mb__after_clear_bit(); 413 wake_up_bit(&gl->gl_flags, GLF_DEMOTE); 414 } 415 416 /** 417 * finish_xmote - The DLM has replied to one of our lock requests 418 * @gl: The glock 419 * @ret: The status from the DLM 420 * 421 */ 422 423 static void finish_xmote(struct gfs2_glock *gl, unsigned int ret) 424 { 425 const struct gfs2_glock_operations *glops = gl->gl_ops; 426 struct gfs2_holder *gh; 427 unsigned state = ret & LM_OUT_ST_MASK; 428 int rv; 429 430 spin_lock(&gl->gl_spin); 431 trace_gfs2_glock_state_change(gl, state); 432 state_change(gl, state); 433 gh = find_first_waiter(gl); 434 435 /* Demote to UN request arrived during demote to SH or DF */ 436 if (test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags) && 437 state != LM_ST_UNLOCKED && gl->gl_demote_state == LM_ST_UNLOCKED) 438 gl->gl_target = LM_ST_UNLOCKED; 439 440 /* Check for state != intended state */ 441 if (unlikely(state != gl->gl_target)) { 442 if (gh && !test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags)) { 443 /* move to back of queue and try next entry */ 444 if (ret & LM_OUT_CANCELED) { 445 if ((gh->gh_flags & LM_FLAG_PRIORITY) == 0) 446 list_move_tail(&gh->gh_list, &gl->gl_holders); 447 gh = find_first_waiter(gl); 448 gl->gl_target = gh->gh_state; 449 goto retry; 450 } 451 /* Some error or failed "try lock" - report it */ 452 if ((ret & LM_OUT_ERROR) || 453 (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB))) { 454 gl->gl_target = gl->gl_state; 455 do_error(gl, ret); 456 goto out; 457 } 458 } 459 switch(state) { 460 /* Unlocked due to conversion deadlock, try again */ 461 case LM_ST_UNLOCKED: 462 retry: 463 do_xmote(gl, gh, gl->gl_target); 464 break; 465 /* Conversion fails, unlock and try again */ 466 case LM_ST_SHARED: 467 case LM_ST_DEFERRED: 468 do_xmote(gl, gh, LM_ST_UNLOCKED); 469 break; 470 default: /* Everything else */ 471 printk(KERN_ERR "GFS2: wanted %u got %u\n", gl->gl_target, state); 472 GLOCK_BUG_ON(gl, 1); 473 } 474 spin_unlock(&gl->gl_spin); 475 return; 476 } 477 478 /* Fast path - we got what we asked for */ 479 if (test_and_clear_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags)) 480 gfs2_demote_wake(gl); 481 if (state != LM_ST_UNLOCKED) { 482 if (glops->go_xmote_bh) { 483 spin_unlock(&gl->gl_spin); 484 rv = glops->go_xmote_bh(gl, gh); 485 spin_lock(&gl->gl_spin); 486 if (rv) { 487 do_error(gl, rv); 488 goto out; 489 } 490 } 491 rv = do_promote(gl); 492 if (rv == 2) 493 goto out_locked; 494 } 495 out: 496 clear_bit(GLF_LOCK, &gl->gl_flags); 497 out_locked: 498 spin_unlock(&gl->gl_spin); 499 } 500 501 /** 502 * do_xmote - Calls the DLM to change the state of a lock 503 * @gl: The lock state 504 * @gh: The holder (only for promotes) 505 * @target: The target lock state 506 * 507 */ 508 509 static void do_xmote(struct gfs2_glock *gl, struct gfs2_holder *gh, unsigned int target) 510 __releases(&gl->gl_spin) 511 __acquires(&gl->gl_spin) 512 { 513 const struct gfs2_glock_operations *glops = gl->gl_ops; 514 struct gfs2_sbd *sdp = gl->gl_sbd; 515 unsigned int lck_flags = gh ? gh->gh_flags : 0; 516 int ret; 517 518 lck_flags &= (LM_FLAG_TRY | LM_FLAG_TRY_1CB | LM_FLAG_NOEXP | 519 LM_FLAG_PRIORITY); 520 GLOCK_BUG_ON(gl, gl->gl_state == target); 521 GLOCK_BUG_ON(gl, gl->gl_state == gl->gl_target); 522 if ((target == LM_ST_UNLOCKED || target == LM_ST_DEFERRED) && 523 glops->go_inval) { 524 set_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags); 525 do_error(gl, 0); /* Fail queued try locks */ 526 } 527 gl->gl_req = target; 528 set_bit(GLF_BLOCKING, &gl->gl_flags); 529 if ((gl->gl_req == LM_ST_UNLOCKED) || 530 (gl->gl_state == LM_ST_EXCLUSIVE) || 531 (lck_flags & (LM_FLAG_TRY|LM_FLAG_TRY_1CB))) 532 clear_bit(GLF_BLOCKING, &gl->gl_flags); 533 spin_unlock(&gl->gl_spin); 534 if (glops->go_sync) 535 glops->go_sync(gl); 536 if (test_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags)) 537 glops->go_inval(gl, target == LM_ST_DEFERRED ? 0 : DIO_METADATA); 538 clear_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags); 539 540 gfs2_glock_hold(gl); 541 if (sdp->sd_lockstruct.ls_ops->lm_lock) { 542 /* lock_dlm */ 543 ret = sdp->sd_lockstruct.ls_ops->lm_lock(gl, target, lck_flags); 544 if (ret) { 545 printk(KERN_ERR "GFS2: lm_lock ret %d\n", ret); 546 GLOCK_BUG_ON(gl, 1); 547 } 548 } else { /* lock_nolock */ 549 finish_xmote(gl, target); 550 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0) 551 gfs2_glock_put(gl); 552 } 553 554 spin_lock(&gl->gl_spin); 555 } 556 557 /** 558 * find_first_holder - find the first "holder" gh 559 * @gl: the glock 560 */ 561 562 static inline struct gfs2_holder *find_first_holder(const struct gfs2_glock *gl) 563 { 564 struct gfs2_holder *gh; 565 566 if (!list_empty(&gl->gl_holders)) { 567 gh = list_entry(gl->gl_holders.next, struct gfs2_holder, gh_list); 568 if (test_bit(HIF_HOLDER, &gh->gh_iflags)) 569 return gh; 570 } 571 return NULL; 572 } 573 574 /** 575 * run_queue - do all outstanding tasks related to a glock 576 * @gl: The glock in question 577 * @nonblock: True if we must not block in run_queue 578 * 579 */ 580 581 static void run_queue(struct gfs2_glock *gl, const int nonblock) 582 __releases(&gl->gl_spin) 583 __acquires(&gl->gl_spin) 584 { 585 struct gfs2_holder *gh = NULL; 586 int ret; 587 588 if (test_and_set_bit(GLF_LOCK, &gl->gl_flags)) 589 return; 590 591 GLOCK_BUG_ON(gl, test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags)); 592 593 if (test_bit(GLF_DEMOTE, &gl->gl_flags) && 594 gl->gl_demote_state != gl->gl_state) { 595 if (find_first_holder(gl)) 596 goto out_unlock; 597 if (nonblock) 598 goto out_sched; 599 set_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags); 600 GLOCK_BUG_ON(gl, gl->gl_demote_state == LM_ST_EXCLUSIVE); 601 gl->gl_target = gl->gl_demote_state; 602 } else { 603 if (test_bit(GLF_DEMOTE, &gl->gl_flags)) 604 gfs2_demote_wake(gl); 605 ret = do_promote(gl); 606 if (ret == 0) 607 goto out_unlock; 608 if (ret == 2) 609 goto out; 610 gh = find_first_waiter(gl); 611 gl->gl_target = gh->gh_state; 612 if (!(gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB))) 613 do_error(gl, 0); /* Fail queued try locks */ 614 } 615 do_xmote(gl, gh, gl->gl_target); 616 out: 617 return; 618 619 out_sched: 620 clear_bit(GLF_LOCK, &gl->gl_flags); 621 smp_mb__after_clear_bit(); 622 gl->gl_lockref.count++; 623 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0) 624 gl->gl_lockref.count--; 625 return; 626 627 out_unlock: 628 clear_bit(GLF_LOCK, &gl->gl_flags); 629 smp_mb__after_clear_bit(); 630 return; 631 } 632 633 static void delete_work_func(struct work_struct *work) 634 { 635 struct gfs2_glock *gl = container_of(work, struct gfs2_glock, gl_delete); 636 struct gfs2_sbd *sdp = gl->gl_sbd; 637 struct gfs2_inode *ip; 638 struct inode *inode; 639 u64 no_addr = gl->gl_name.ln_number; 640 641 ip = gl->gl_object; 642 /* Note: Unsafe to dereference ip as we don't hold right refs/locks */ 643 644 if (ip) 645 inode = gfs2_ilookup(sdp->sd_vfs, no_addr, 1); 646 else 647 inode = gfs2_lookup_by_inum(sdp, no_addr, NULL, GFS2_BLKST_UNLINKED); 648 if (inode && !IS_ERR(inode)) { 649 d_prune_aliases(inode); 650 iput(inode); 651 } 652 gfs2_glock_put(gl); 653 } 654 655 static void glock_work_func(struct work_struct *work) 656 { 657 unsigned long delay = 0; 658 struct gfs2_glock *gl = container_of(work, struct gfs2_glock, gl_work.work); 659 int drop_ref = 0; 660 661 if (test_and_clear_bit(GLF_REPLY_PENDING, &gl->gl_flags)) { 662 finish_xmote(gl, gl->gl_reply); 663 drop_ref = 1; 664 } 665 spin_lock(&gl->gl_spin); 666 if (test_bit(GLF_PENDING_DEMOTE, &gl->gl_flags) && 667 gl->gl_state != LM_ST_UNLOCKED && 668 gl->gl_demote_state != LM_ST_EXCLUSIVE) { 669 unsigned long holdtime, now = jiffies; 670 671 holdtime = gl->gl_tchange + gl->gl_hold_time; 672 if (time_before(now, holdtime)) 673 delay = holdtime - now; 674 675 if (!delay) { 676 clear_bit(GLF_PENDING_DEMOTE, &gl->gl_flags); 677 set_bit(GLF_DEMOTE, &gl->gl_flags); 678 } 679 } 680 run_queue(gl, 0); 681 spin_unlock(&gl->gl_spin); 682 if (!delay) 683 gfs2_glock_put(gl); 684 else { 685 if (gl->gl_name.ln_type != LM_TYPE_INODE) 686 delay = 0; 687 if (queue_delayed_work(glock_workqueue, &gl->gl_work, delay) == 0) 688 gfs2_glock_put(gl); 689 } 690 if (drop_ref) 691 gfs2_glock_put(gl); 692 } 693 694 /** 695 * gfs2_glock_get() - Get a glock, or create one if one doesn't exist 696 * @sdp: The GFS2 superblock 697 * @number: the lock number 698 * @glops: The glock_operations to use 699 * @create: If 0, don't create the glock if it doesn't exist 700 * @glp: the glock is returned here 701 * 702 * This does not lock a glock, just finds/creates structures for one. 703 * 704 * Returns: errno 705 */ 706 707 int gfs2_glock_get(struct gfs2_sbd *sdp, u64 number, 708 const struct gfs2_glock_operations *glops, int create, 709 struct gfs2_glock **glp) 710 { 711 struct super_block *s = sdp->sd_vfs; 712 struct lm_lockname name = { .ln_number = number, .ln_type = glops->go_type }; 713 struct gfs2_glock *gl, *tmp; 714 unsigned int hash = gl_hash(sdp, &name); 715 struct address_space *mapping; 716 struct kmem_cache *cachep; 717 718 rcu_read_lock(); 719 gl = search_bucket(hash, sdp, &name); 720 rcu_read_unlock(); 721 722 *glp = gl; 723 if (gl) 724 return 0; 725 if (!create) 726 return -ENOENT; 727 728 if (glops->go_flags & GLOF_ASPACE) 729 cachep = gfs2_glock_aspace_cachep; 730 else 731 cachep = gfs2_glock_cachep; 732 gl = kmem_cache_alloc(cachep, GFP_KERNEL); 733 if (!gl) 734 return -ENOMEM; 735 736 memset(&gl->gl_lksb, 0, sizeof(struct dlm_lksb)); 737 738 if (glops->go_flags & GLOF_LVB) { 739 gl->gl_lksb.sb_lvbptr = kzalloc(GFS2_MIN_LVB_SIZE, GFP_KERNEL); 740 if (!gl->gl_lksb.sb_lvbptr) { 741 kmem_cache_free(cachep, gl); 742 return -ENOMEM; 743 } 744 } 745 746 atomic_inc(&sdp->sd_glock_disposal); 747 gl->gl_sbd = sdp; 748 gl->gl_flags = 0; 749 gl->gl_name = name; 750 gl->gl_lockref.count = 1; 751 gl->gl_state = LM_ST_UNLOCKED; 752 gl->gl_target = LM_ST_UNLOCKED; 753 gl->gl_demote_state = LM_ST_EXCLUSIVE; 754 gl->gl_hash = hash; 755 gl->gl_ops = glops; 756 gl->gl_dstamp = ktime_set(0, 0); 757 preempt_disable(); 758 /* We use the global stats to estimate the initial per-glock stats */ 759 gl->gl_stats = this_cpu_ptr(sdp->sd_lkstats)->lkstats[glops->go_type]; 760 preempt_enable(); 761 gl->gl_stats.stats[GFS2_LKS_DCOUNT] = 0; 762 gl->gl_stats.stats[GFS2_LKS_QCOUNT] = 0; 763 gl->gl_tchange = jiffies; 764 gl->gl_object = NULL; 765 gl->gl_hold_time = GL_GLOCK_DFT_HOLD; 766 INIT_DELAYED_WORK(&gl->gl_work, glock_work_func); 767 INIT_WORK(&gl->gl_delete, delete_work_func); 768 769 mapping = gfs2_glock2aspace(gl); 770 if (mapping) { 771 mapping->a_ops = &gfs2_meta_aops; 772 mapping->host = s->s_bdev->bd_inode; 773 mapping->flags = 0; 774 mapping_set_gfp_mask(mapping, GFP_NOFS); 775 mapping->private_data = NULL; 776 mapping->backing_dev_info = s->s_bdi; 777 mapping->writeback_index = 0; 778 } 779 780 spin_lock_bucket(hash); 781 tmp = search_bucket(hash, sdp, &name); 782 if (tmp) { 783 spin_unlock_bucket(hash); 784 kfree(gl->gl_lksb.sb_lvbptr); 785 kmem_cache_free(cachep, gl); 786 atomic_dec(&sdp->sd_glock_disposal); 787 gl = tmp; 788 } else { 789 hlist_bl_add_head_rcu(&gl->gl_list, &gl_hash_table[hash]); 790 spin_unlock_bucket(hash); 791 } 792 793 *glp = gl; 794 795 return 0; 796 } 797 798 /** 799 * gfs2_holder_init - initialize a struct gfs2_holder in the default way 800 * @gl: the glock 801 * @state: the state we're requesting 802 * @flags: the modifier flags 803 * @gh: the holder structure 804 * 805 */ 806 807 void gfs2_holder_init(struct gfs2_glock *gl, unsigned int state, unsigned flags, 808 struct gfs2_holder *gh) 809 { 810 INIT_LIST_HEAD(&gh->gh_list); 811 gh->gh_gl = gl; 812 gh->gh_ip = (unsigned long)__builtin_return_address(0); 813 gh->gh_owner_pid = get_pid(task_pid(current)); 814 gh->gh_state = state; 815 gh->gh_flags = flags; 816 gh->gh_error = 0; 817 gh->gh_iflags = 0; 818 gfs2_glock_hold(gl); 819 } 820 821 /** 822 * gfs2_holder_reinit - reinitialize a struct gfs2_holder so we can requeue it 823 * @state: the state we're requesting 824 * @flags: the modifier flags 825 * @gh: the holder structure 826 * 827 * Don't mess with the glock. 828 * 829 */ 830 831 void gfs2_holder_reinit(unsigned int state, unsigned flags, struct gfs2_holder *gh) 832 { 833 gh->gh_state = state; 834 gh->gh_flags = flags; 835 gh->gh_iflags = 0; 836 gh->gh_ip = (unsigned long)__builtin_return_address(0); 837 if (gh->gh_owner_pid) 838 put_pid(gh->gh_owner_pid); 839 gh->gh_owner_pid = get_pid(task_pid(current)); 840 } 841 842 /** 843 * gfs2_holder_uninit - uninitialize a holder structure (drop glock reference) 844 * @gh: the holder structure 845 * 846 */ 847 848 void gfs2_holder_uninit(struct gfs2_holder *gh) 849 { 850 put_pid(gh->gh_owner_pid); 851 gfs2_glock_put(gh->gh_gl); 852 gh->gh_gl = NULL; 853 gh->gh_ip = 0; 854 } 855 856 /** 857 * gfs2_glock_holder_wait 858 * @word: unused 859 * 860 * This function and gfs2_glock_demote_wait both show up in the WCHAN 861 * field. Thus I've separated these otherwise identical functions in 862 * order to be more informative to the user. 863 */ 864 865 static int gfs2_glock_holder_wait(void *word) 866 { 867 schedule(); 868 return 0; 869 } 870 871 static int gfs2_glock_demote_wait(void *word) 872 { 873 schedule(); 874 return 0; 875 } 876 877 /** 878 * gfs2_glock_wait - wait on a glock acquisition 879 * @gh: the glock holder 880 * 881 * Returns: 0 on success 882 */ 883 884 int gfs2_glock_wait(struct gfs2_holder *gh) 885 { 886 unsigned long time1 = jiffies; 887 888 might_sleep(); 889 wait_on_bit(&gh->gh_iflags, HIF_WAIT, gfs2_glock_holder_wait, TASK_UNINTERRUPTIBLE); 890 if (time_after(jiffies, time1 + HZ)) /* have we waited > a second? */ 891 /* Lengthen the minimum hold time. */ 892 gh->gh_gl->gl_hold_time = min(gh->gh_gl->gl_hold_time + 893 GL_GLOCK_HOLD_INCR, 894 GL_GLOCK_MAX_HOLD); 895 return gh->gh_error; 896 } 897 898 /** 899 * handle_callback - process a demote request 900 * @gl: the glock 901 * @state: the state the caller wants us to change to 902 * 903 * There are only two requests that we are going to see in actual 904 * practise: LM_ST_SHARED and LM_ST_UNLOCKED 905 */ 906 907 static void handle_callback(struct gfs2_glock *gl, unsigned int state, 908 unsigned long delay, bool remote) 909 { 910 int bit = delay ? GLF_PENDING_DEMOTE : GLF_DEMOTE; 911 912 set_bit(bit, &gl->gl_flags); 913 if (gl->gl_demote_state == LM_ST_EXCLUSIVE) { 914 gl->gl_demote_state = state; 915 gl->gl_demote_time = jiffies; 916 } else if (gl->gl_demote_state != LM_ST_UNLOCKED && 917 gl->gl_demote_state != state) { 918 gl->gl_demote_state = LM_ST_UNLOCKED; 919 } 920 if (gl->gl_ops->go_callback) 921 gl->gl_ops->go_callback(gl, remote); 922 trace_gfs2_demote_rq(gl, remote); 923 } 924 925 void gfs2_print_dbg(struct seq_file *seq, const char *fmt, ...) 926 { 927 struct va_format vaf; 928 va_list args; 929 930 va_start(args, fmt); 931 932 if (seq) { 933 seq_vprintf(seq, fmt, args); 934 } else { 935 vaf.fmt = fmt; 936 vaf.va = &args; 937 938 printk(KERN_ERR " %pV", &vaf); 939 } 940 941 va_end(args); 942 } 943 944 /** 945 * add_to_queue - Add a holder to the wait queue (but look for recursion) 946 * @gh: the holder structure to add 947 * 948 * Eventually we should move the recursive locking trap to a 949 * debugging option or something like that. This is the fast 950 * path and needs to have the minimum number of distractions. 951 * 952 */ 953 954 static inline void add_to_queue(struct gfs2_holder *gh) 955 __releases(&gl->gl_spin) 956 __acquires(&gl->gl_spin) 957 { 958 struct gfs2_glock *gl = gh->gh_gl; 959 struct gfs2_sbd *sdp = gl->gl_sbd; 960 struct list_head *insert_pt = NULL; 961 struct gfs2_holder *gh2; 962 int try_futile = 0; 963 964 BUG_ON(gh->gh_owner_pid == NULL); 965 if (test_and_set_bit(HIF_WAIT, &gh->gh_iflags)) 966 BUG(); 967 968 if (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)) { 969 if (test_bit(GLF_LOCK, &gl->gl_flags)) 970 try_futile = !may_grant(gl, gh); 971 if (test_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags)) 972 goto fail; 973 } 974 975 list_for_each_entry(gh2, &gl->gl_holders, gh_list) { 976 if (unlikely(gh2->gh_owner_pid == gh->gh_owner_pid && 977 (gh->gh_gl->gl_ops->go_type != LM_TYPE_FLOCK))) 978 goto trap_recursive; 979 if (try_futile && 980 !(gh2->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB))) { 981 fail: 982 gh->gh_error = GLR_TRYFAILED; 983 gfs2_holder_wake(gh); 984 return; 985 } 986 if (test_bit(HIF_HOLDER, &gh2->gh_iflags)) 987 continue; 988 if (unlikely((gh->gh_flags & LM_FLAG_PRIORITY) && !insert_pt)) 989 insert_pt = &gh2->gh_list; 990 } 991 set_bit(GLF_QUEUED, &gl->gl_flags); 992 trace_gfs2_glock_queue(gh, 1); 993 gfs2_glstats_inc(gl, GFS2_LKS_QCOUNT); 994 gfs2_sbstats_inc(gl, GFS2_LKS_QCOUNT); 995 if (likely(insert_pt == NULL)) { 996 list_add_tail(&gh->gh_list, &gl->gl_holders); 997 if (unlikely(gh->gh_flags & LM_FLAG_PRIORITY)) 998 goto do_cancel; 999 return; 1000 } 1001 list_add_tail(&gh->gh_list, insert_pt); 1002 do_cancel: 1003 gh = list_entry(gl->gl_holders.next, struct gfs2_holder, gh_list); 1004 if (!(gh->gh_flags & LM_FLAG_PRIORITY)) { 1005 spin_unlock(&gl->gl_spin); 1006 if (sdp->sd_lockstruct.ls_ops->lm_cancel) 1007 sdp->sd_lockstruct.ls_ops->lm_cancel(gl); 1008 spin_lock(&gl->gl_spin); 1009 } 1010 return; 1011 1012 trap_recursive: 1013 printk(KERN_ERR "original: %pSR\n", (void *)gh2->gh_ip); 1014 printk(KERN_ERR "pid: %d\n", pid_nr(gh2->gh_owner_pid)); 1015 printk(KERN_ERR "lock type: %d req lock state : %d\n", 1016 gh2->gh_gl->gl_name.ln_type, gh2->gh_state); 1017 printk(KERN_ERR "new: %pSR\n", (void *)gh->gh_ip); 1018 printk(KERN_ERR "pid: %d\n", pid_nr(gh->gh_owner_pid)); 1019 printk(KERN_ERR "lock type: %d req lock state : %d\n", 1020 gh->gh_gl->gl_name.ln_type, gh->gh_state); 1021 gfs2_dump_glock(NULL, gl); 1022 BUG(); 1023 } 1024 1025 /** 1026 * gfs2_glock_nq - enqueue a struct gfs2_holder onto a glock (acquire a glock) 1027 * @gh: the holder structure 1028 * 1029 * if (gh->gh_flags & GL_ASYNC), this never returns an error 1030 * 1031 * Returns: 0, GLR_TRYFAILED, or errno on failure 1032 */ 1033 1034 int gfs2_glock_nq(struct gfs2_holder *gh) 1035 { 1036 struct gfs2_glock *gl = gh->gh_gl; 1037 struct gfs2_sbd *sdp = gl->gl_sbd; 1038 int error = 0; 1039 1040 if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags))) 1041 return -EIO; 1042 1043 if (test_bit(GLF_LRU, &gl->gl_flags)) 1044 gfs2_glock_remove_from_lru(gl); 1045 1046 spin_lock(&gl->gl_spin); 1047 add_to_queue(gh); 1048 if ((LM_FLAG_NOEXP & gh->gh_flags) && 1049 test_and_clear_bit(GLF_FROZEN, &gl->gl_flags)) 1050 set_bit(GLF_REPLY_PENDING, &gl->gl_flags); 1051 run_queue(gl, 1); 1052 spin_unlock(&gl->gl_spin); 1053 1054 if (!(gh->gh_flags & GL_ASYNC)) 1055 error = gfs2_glock_wait(gh); 1056 1057 return error; 1058 } 1059 1060 /** 1061 * gfs2_glock_poll - poll to see if an async request has been completed 1062 * @gh: the holder 1063 * 1064 * Returns: 1 if the request is ready to be gfs2_glock_wait()ed on 1065 */ 1066 1067 int gfs2_glock_poll(struct gfs2_holder *gh) 1068 { 1069 return test_bit(HIF_WAIT, &gh->gh_iflags) ? 0 : 1; 1070 } 1071 1072 /** 1073 * gfs2_glock_dq - dequeue a struct gfs2_holder from a glock (release a glock) 1074 * @gh: the glock holder 1075 * 1076 */ 1077 1078 void gfs2_glock_dq(struct gfs2_holder *gh) 1079 { 1080 struct gfs2_glock *gl = gh->gh_gl; 1081 const struct gfs2_glock_operations *glops = gl->gl_ops; 1082 unsigned delay = 0; 1083 int fast_path = 0; 1084 1085 spin_lock(&gl->gl_spin); 1086 if (gh->gh_flags & GL_NOCACHE) 1087 handle_callback(gl, LM_ST_UNLOCKED, 0, false); 1088 1089 list_del_init(&gh->gh_list); 1090 if (find_first_holder(gl) == NULL) { 1091 if (glops->go_unlock) { 1092 GLOCK_BUG_ON(gl, test_and_set_bit(GLF_LOCK, &gl->gl_flags)); 1093 spin_unlock(&gl->gl_spin); 1094 glops->go_unlock(gh); 1095 spin_lock(&gl->gl_spin); 1096 clear_bit(GLF_LOCK, &gl->gl_flags); 1097 } 1098 if (list_empty(&gl->gl_holders) && 1099 !test_bit(GLF_PENDING_DEMOTE, &gl->gl_flags) && 1100 !test_bit(GLF_DEMOTE, &gl->gl_flags)) 1101 fast_path = 1; 1102 } 1103 if (!test_bit(GLF_LFLUSH, &gl->gl_flags) && demote_ok(gl)) 1104 gfs2_glock_add_to_lru(gl); 1105 1106 trace_gfs2_glock_queue(gh, 0); 1107 spin_unlock(&gl->gl_spin); 1108 if (likely(fast_path)) 1109 return; 1110 1111 gfs2_glock_hold(gl); 1112 if (test_bit(GLF_PENDING_DEMOTE, &gl->gl_flags) && 1113 !test_bit(GLF_DEMOTE, &gl->gl_flags) && 1114 gl->gl_name.ln_type == LM_TYPE_INODE) 1115 delay = gl->gl_hold_time; 1116 if (queue_delayed_work(glock_workqueue, &gl->gl_work, delay) == 0) 1117 gfs2_glock_put(gl); 1118 } 1119 1120 void gfs2_glock_dq_wait(struct gfs2_holder *gh) 1121 { 1122 struct gfs2_glock *gl = gh->gh_gl; 1123 gfs2_glock_dq(gh); 1124 might_sleep(); 1125 wait_on_bit(&gl->gl_flags, GLF_DEMOTE, gfs2_glock_demote_wait, TASK_UNINTERRUPTIBLE); 1126 } 1127 1128 /** 1129 * gfs2_glock_dq_uninit - dequeue a holder from a glock and initialize it 1130 * @gh: the holder structure 1131 * 1132 */ 1133 1134 void gfs2_glock_dq_uninit(struct gfs2_holder *gh) 1135 { 1136 gfs2_glock_dq(gh); 1137 gfs2_holder_uninit(gh); 1138 } 1139 1140 /** 1141 * gfs2_glock_nq_num - acquire a glock based on lock number 1142 * @sdp: the filesystem 1143 * @number: the lock number 1144 * @glops: the glock operations for the type of glock 1145 * @state: the state to acquire the glock in 1146 * @flags: modifier flags for the acquisition 1147 * @gh: the struct gfs2_holder 1148 * 1149 * Returns: errno 1150 */ 1151 1152 int gfs2_glock_nq_num(struct gfs2_sbd *sdp, u64 number, 1153 const struct gfs2_glock_operations *glops, 1154 unsigned int state, int flags, struct gfs2_holder *gh) 1155 { 1156 struct gfs2_glock *gl; 1157 int error; 1158 1159 error = gfs2_glock_get(sdp, number, glops, CREATE, &gl); 1160 if (!error) { 1161 error = gfs2_glock_nq_init(gl, state, flags, gh); 1162 gfs2_glock_put(gl); 1163 } 1164 1165 return error; 1166 } 1167 1168 /** 1169 * glock_compare - Compare two struct gfs2_glock structures for sorting 1170 * @arg_a: the first structure 1171 * @arg_b: the second structure 1172 * 1173 */ 1174 1175 static int glock_compare(const void *arg_a, const void *arg_b) 1176 { 1177 const struct gfs2_holder *gh_a = *(const struct gfs2_holder **)arg_a; 1178 const struct gfs2_holder *gh_b = *(const struct gfs2_holder **)arg_b; 1179 const struct lm_lockname *a = &gh_a->gh_gl->gl_name; 1180 const struct lm_lockname *b = &gh_b->gh_gl->gl_name; 1181 1182 if (a->ln_number > b->ln_number) 1183 return 1; 1184 if (a->ln_number < b->ln_number) 1185 return -1; 1186 BUG_ON(gh_a->gh_gl->gl_ops->go_type == gh_b->gh_gl->gl_ops->go_type); 1187 return 0; 1188 } 1189 1190 /** 1191 * nq_m_sync - synchonously acquire more than one glock in deadlock free order 1192 * @num_gh: the number of structures 1193 * @ghs: an array of struct gfs2_holder structures 1194 * 1195 * Returns: 0 on success (all glocks acquired), 1196 * errno on failure (no glocks acquired) 1197 */ 1198 1199 static int nq_m_sync(unsigned int num_gh, struct gfs2_holder *ghs, 1200 struct gfs2_holder **p) 1201 { 1202 unsigned int x; 1203 int error = 0; 1204 1205 for (x = 0; x < num_gh; x++) 1206 p[x] = &ghs[x]; 1207 1208 sort(p, num_gh, sizeof(struct gfs2_holder *), glock_compare, NULL); 1209 1210 for (x = 0; x < num_gh; x++) { 1211 p[x]->gh_flags &= ~(LM_FLAG_TRY | GL_ASYNC); 1212 1213 error = gfs2_glock_nq(p[x]); 1214 if (error) { 1215 while (x--) 1216 gfs2_glock_dq(p[x]); 1217 break; 1218 } 1219 } 1220 1221 return error; 1222 } 1223 1224 /** 1225 * gfs2_glock_nq_m - acquire multiple glocks 1226 * @num_gh: the number of structures 1227 * @ghs: an array of struct gfs2_holder structures 1228 * 1229 * 1230 * Returns: 0 on success (all glocks acquired), 1231 * errno on failure (no glocks acquired) 1232 */ 1233 1234 int gfs2_glock_nq_m(unsigned int num_gh, struct gfs2_holder *ghs) 1235 { 1236 struct gfs2_holder *tmp[4]; 1237 struct gfs2_holder **pph = tmp; 1238 int error = 0; 1239 1240 switch(num_gh) { 1241 case 0: 1242 return 0; 1243 case 1: 1244 ghs->gh_flags &= ~(LM_FLAG_TRY | GL_ASYNC); 1245 return gfs2_glock_nq(ghs); 1246 default: 1247 if (num_gh <= 4) 1248 break; 1249 pph = kmalloc(num_gh * sizeof(struct gfs2_holder *), GFP_NOFS); 1250 if (!pph) 1251 return -ENOMEM; 1252 } 1253 1254 error = nq_m_sync(num_gh, ghs, pph); 1255 1256 if (pph != tmp) 1257 kfree(pph); 1258 1259 return error; 1260 } 1261 1262 /** 1263 * gfs2_glock_dq_m - release multiple glocks 1264 * @num_gh: the number of structures 1265 * @ghs: an array of struct gfs2_holder structures 1266 * 1267 */ 1268 1269 void gfs2_glock_dq_m(unsigned int num_gh, struct gfs2_holder *ghs) 1270 { 1271 while (num_gh--) 1272 gfs2_glock_dq(&ghs[num_gh]); 1273 } 1274 1275 void gfs2_glock_cb(struct gfs2_glock *gl, unsigned int state) 1276 { 1277 unsigned long delay = 0; 1278 unsigned long holdtime; 1279 unsigned long now = jiffies; 1280 1281 gfs2_glock_hold(gl); 1282 holdtime = gl->gl_tchange + gl->gl_hold_time; 1283 if (test_bit(GLF_QUEUED, &gl->gl_flags) && 1284 gl->gl_name.ln_type == LM_TYPE_INODE) { 1285 if (time_before(now, holdtime)) 1286 delay = holdtime - now; 1287 if (test_bit(GLF_REPLY_PENDING, &gl->gl_flags)) 1288 delay = gl->gl_hold_time; 1289 } 1290 1291 spin_lock(&gl->gl_spin); 1292 handle_callback(gl, state, delay, true); 1293 spin_unlock(&gl->gl_spin); 1294 if (queue_delayed_work(glock_workqueue, &gl->gl_work, delay) == 0) 1295 gfs2_glock_put(gl); 1296 } 1297 1298 /** 1299 * gfs2_should_freeze - Figure out if glock should be frozen 1300 * @gl: The glock in question 1301 * 1302 * Glocks are not frozen if (a) the result of the dlm operation is 1303 * an error, (b) the locking operation was an unlock operation or 1304 * (c) if there is a "noexp" flagged request anywhere in the queue 1305 * 1306 * Returns: 1 if freezing should occur, 0 otherwise 1307 */ 1308 1309 static int gfs2_should_freeze(const struct gfs2_glock *gl) 1310 { 1311 const struct gfs2_holder *gh; 1312 1313 if (gl->gl_reply & ~LM_OUT_ST_MASK) 1314 return 0; 1315 if (gl->gl_target == LM_ST_UNLOCKED) 1316 return 0; 1317 1318 list_for_each_entry(gh, &gl->gl_holders, gh_list) { 1319 if (test_bit(HIF_HOLDER, &gh->gh_iflags)) 1320 continue; 1321 if (LM_FLAG_NOEXP & gh->gh_flags) 1322 return 0; 1323 } 1324 1325 return 1; 1326 } 1327 1328 /** 1329 * gfs2_glock_complete - Callback used by locking 1330 * @gl: Pointer to the glock 1331 * @ret: The return value from the dlm 1332 * 1333 * The gl_reply field is under the gl_spin lock so that it is ok 1334 * to use a bitfield shared with other glock state fields. 1335 */ 1336 1337 void gfs2_glock_complete(struct gfs2_glock *gl, int ret) 1338 { 1339 struct lm_lockstruct *ls = &gl->gl_sbd->sd_lockstruct; 1340 1341 spin_lock(&gl->gl_spin); 1342 gl->gl_reply = ret; 1343 1344 if (unlikely(test_bit(DFL_BLOCK_LOCKS, &ls->ls_recover_flags))) { 1345 if (gfs2_should_freeze(gl)) { 1346 set_bit(GLF_FROZEN, &gl->gl_flags); 1347 spin_unlock(&gl->gl_spin); 1348 return; 1349 } 1350 } 1351 1352 gl->gl_lockref.count++; 1353 set_bit(GLF_REPLY_PENDING, &gl->gl_flags); 1354 spin_unlock(&gl->gl_spin); 1355 1356 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0) 1357 gfs2_glock_put(gl); 1358 } 1359 1360 static int glock_cmp(void *priv, struct list_head *a, struct list_head *b) 1361 { 1362 struct gfs2_glock *gla, *glb; 1363 1364 gla = list_entry(a, struct gfs2_glock, gl_lru); 1365 glb = list_entry(b, struct gfs2_glock, gl_lru); 1366 1367 if (gla->gl_name.ln_number > glb->gl_name.ln_number) 1368 return 1; 1369 if (gla->gl_name.ln_number < glb->gl_name.ln_number) 1370 return -1; 1371 1372 return 0; 1373 } 1374 1375 /** 1376 * gfs2_dispose_glock_lru - Demote a list of glocks 1377 * @list: The list to dispose of 1378 * 1379 * Disposing of glocks may involve disk accesses, so that here we sort 1380 * the glocks by number (i.e. disk location of the inodes) so that if 1381 * there are any such accesses, they'll be sent in order (mostly). 1382 * 1383 * Must be called under the lru_lock, but may drop and retake this 1384 * lock. While the lru_lock is dropped, entries may vanish from the 1385 * list, but no new entries will appear on the list (since it is 1386 * private) 1387 */ 1388 1389 static void gfs2_dispose_glock_lru(struct list_head *list) 1390 __releases(&lru_lock) 1391 __acquires(&lru_lock) 1392 { 1393 struct gfs2_glock *gl; 1394 1395 list_sort(NULL, list, glock_cmp); 1396 1397 while(!list_empty(list)) { 1398 gl = list_entry(list->next, struct gfs2_glock, gl_lru); 1399 list_del_init(&gl->gl_lru); 1400 if (!spin_trylock(&gl->gl_spin)) { 1401 list_add(&gl->gl_lru, &lru_list); 1402 atomic_inc(&lru_count); 1403 continue; 1404 } 1405 clear_bit(GLF_LRU, &gl->gl_flags); 1406 spin_unlock(&lru_lock); 1407 gl->gl_lockref.count++; 1408 if (demote_ok(gl)) 1409 handle_callback(gl, LM_ST_UNLOCKED, 0, false); 1410 WARN_ON(!test_and_clear_bit(GLF_LOCK, &gl->gl_flags)); 1411 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0) 1412 gl->gl_lockref.count--; 1413 spin_unlock(&gl->gl_spin); 1414 spin_lock(&lru_lock); 1415 } 1416 } 1417 1418 /** 1419 * gfs2_scan_glock_lru - Scan the LRU looking for locks to demote 1420 * @nr: The number of entries to scan 1421 * 1422 * This function selects the entries on the LRU which are able to 1423 * be demoted, and then kicks off the process by calling 1424 * gfs2_dispose_glock_lru() above. 1425 */ 1426 1427 static long gfs2_scan_glock_lru(int nr) 1428 { 1429 struct gfs2_glock *gl; 1430 LIST_HEAD(skipped); 1431 LIST_HEAD(dispose); 1432 long freed = 0; 1433 1434 spin_lock(&lru_lock); 1435 while ((nr-- >= 0) && !list_empty(&lru_list)) { 1436 gl = list_entry(lru_list.next, struct gfs2_glock, gl_lru); 1437 1438 /* Test for being demotable */ 1439 if (!test_and_set_bit(GLF_LOCK, &gl->gl_flags)) { 1440 list_move(&gl->gl_lru, &dispose); 1441 atomic_dec(&lru_count); 1442 freed++; 1443 continue; 1444 } 1445 1446 list_move(&gl->gl_lru, &skipped); 1447 } 1448 list_splice(&skipped, &lru_list); 1449 if (!list_empty(&dispose)) 1450 gfs2_dispose_glock_lru(&dispose); 1451 spin_unlock(&lru_lock); 1452 1453 return freed; 1454 } 1455 1456 static unsigned long gfs2_glock_shrink_scan(struct shrinker *shrink, 1457 struct shrink_control *sc) 1458 { 1459 if (!(sc->gfp_mask & __GFP_FS)) 1460 return SHRINK_STOP; 1461 return gfs2_scan_glock_lru(sc->nr_to_scan); 1462 } 1463 1464 static unsigned long gfs2_glock_shrink_count(struct shrinker *shrink, 1465 struct shrink_control *sc) 1466 { 1467 return vfs_pressure_ratio(atomic_read(&lru_count)); 1468 } 1469 1470 static struct shrinker glock_shrinker = { 1471 .seeks = DEFAULT_SEEKS, 1472 .count_objects = gfs2_glock_shrink_count, 1473 .scan_objects = gfs2_glock_shrink_scan, 1474 }; 1475 1476 /** 1477 * examine_bucket - Call a function for glock in a hash bucket 1478 * @examiner: the function 1479 * @sdp: the filesystem 1480 * @bucket: the bucket 1481 * 1482 */ 1483 1484 static void examine_bucket(glock_examiner examiner, const struct gfs2_sbd *sdp, 1485 unsigned int hash) 1486 { 1487 struct gfs2_glock *gl; 1488 struct hlist_bl_head *head = &gl_hash_table[hash]; 1489 struct hlist_bl_node *pos; 1490 1491 rcu_read_lock(); 1492 hlist_bl_for_each_entry_rcu(gl, pos, head, gl_list) { 1493 if ((gl->gl_sbd == sdp) && lockref_get_not_dead(&gl->gl_lockref)) 1494 examiner(gl); 1495 } 1496 rcu_read_unlock(); 1497 cond_resched(); 1498 } 1499 1500 static void glock_hash_walk(glock_examiner examiner, const struct gfs2_sbd *sdp) 1501 { 1502 unsigned x; 1503 1504 for (x = 0; x < GFS2_GL_HASH_SIZE; x++) 1505 examine_bucket(examiner, sdp, x); 1506 } 1507 1508 1509 /** 1510 * thaw_glock - thaw out a glock which has an unprocessed reply waiting 1511 * @gl: The glock to thaw 1512 * 1513 */ 1514 1515 static void thaw_glock(struct gfs2_glock *gl) 1516 { 1517 if (!test_and_clear_bit(GLF_FROZEN, &gl->gl_flags)) 1518 goto out; 1519 set_bit(GLF_REPLY_PENDING, &gl->gl_flags); 1520 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0) { 1521 out: 1522 gfs2_glock_put(gl); 1523 } 1524 } 1525 1526 /** 1527 * clear_glock - look at a glock and see if we can free it from glock cache 1528 * @gl: the glock to look at 1529 * 1530 */ 1531 1532 static void clear_glock(struct gfs2_glock *gl) 1533 { 1534 gfs2_glock_remove_from_lru(gl); 1535 1536 spin_lock(&gl->gl_spin); 1537 if (gl->gl_state != LM_ST_UNLOCKED) 1538 handle_callback(gl, LM_ST_UNLOCKED, 0, false); 1539 spin_unlock(&gl->gl_spin); 1540 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0) 1541 gfs2_glock_put(gl); 1542 } 1543 1544 /** 1545 * gfs2_glock_thaw - Thaw any frozen glocks 1546 * @sdp: The super block 1547 * 1548 */ 1549 1550 void gfs2_glock_thaw(struct gfs2_sbd *sdp) 1551 { 1552 glock_hash_walk(thaw_glock, sdp); 1553 } 1554 1555 static int dump_glock(struct seq_file *seq, struct gfs2_glock *gl) 1556 { 1557 int ret; 1558 spin_lock(&gl->gl_spin); 1559 ret = gfs2_dump_glock(seq, gl); 1560 spin_unlock(&gl->gl_spin); 1561 return ret; 1562 } 1563 1564 static void dump_glock_func(struct gfs2_glock *gl) 1565 { 1566 dump_glock(NULL, gl); 1567 } 1568 1569 /** 1570 * gfs2_gl_hash_clear - Empty out the glock hash table 1571 * @sdp: the filesystem 1572 * @wait: wait until it's all gone 1573 * 1574 * Called when unmounting the filesystem. 1575 */ 1576 1577 void gfs2_gl_hash_clear(struct gfs2_sbd *sdp) 1578 { 1579 set_bit(SDF_SKIP_DLM_UNLOCK, &sdp->sd_flags); 1580 flush_workqueue(glock_workqueue); 1581 glock_hash_walk(clear_glock, sdp); 1582 flush_workqueue(glock_workqueue); 1583 wait_event(sdp->sd_glock_wait, atomic_read(&sdp->sd_glock_disposal) == 0); 1584 glock_hash_walk(dump_glock_func, sdp); 1585 } 1586 1587 void gfs2_glock_finish_truncate(struct gfs2_inode *ip) 1588 { 1589 struct gfs2_glock *gl = ip->i_gl; 1590 int ret; 1591 1592 ret = gfs2_truncatei_resume(ip); 1593 gfs2_assert_withdraw(gl->gl_sbd, ret == 0); 1594 1595 spin_lock(&gl->gl_spin); 1596 clear_bit(GLF_LOCK, &gl->gl_flags); 1597 run_queue(gl, 1); 1598 spin_unlock(&gl->gl_spin); 1599 } 1600 1601 static const char *state2str(unsigned state) 1602 { 1603 switch(state) { 1604 case LM_ST_UNLOCKED: 1605 return "UN"; 1606 case LM_ST_SHARED: 1607 return "SH"; 1608 case LM_ST_DEFERRED: 1609 return "DF"; 1610 case LM_ST_EXCLUSIVE: 1611 return "EX"; 1612 } 1613 return "??"; 1614 } 1615 1616 static const char *hflags2str(char *buf, unsigned flags, unsigned long iflags) 1617 { 1618 char *p = buf; 1619 if (flags & LM_FLAG_TRY) 1620 *p++ = 't'; 1621 if (flags & LM_FLAG_TRY_1CB) 1622 *p++ = 'T'; 1623 if (flags & LM_FLAG_NOEXP) 1624 *p++ = 'e'; 1625 if (flags & LM_FLAG_ANY) 1626 *p++ = 'A'; 1627 if (flags & LM_FLAG_PRIORITY) 1628 *p++ = 'p'; 1629 if (flags & GL_ASYNC) 1630 *p++ = 'a'; 1631 if (flags & GL_EXACT) 1632 *p++ = 'E'; 1633 if (flags & GL_NOCACHE) 1634 *p++ = 'c'; 1635 if (test_bit(HIF_HOLDER, &iflags)) 1636 *p++ = 'H'; 1637 if (test_bit(HIF_WAIT, &iflags)) 1638 *p++ = 'W'; 1639 if (test_bit(HIF_FIRST, &iflags)) 1640 *p++ = 'F'; 1641 *p = 0; 1642 return buf; 1643 } 1644 1645 /** 1646 * dump_holder - print information about a glock holder 1647 * @seq: the seq_file struct 1648 * @gh: the glock holder 1649 * 1650 * Returns: 0 on success, -ENOBUFS when we run out of space 1651 */ 1652 1653 static int dump_holder(struct seq_file *seq, const struct gfs2_holder *gh) 1654 { 1655 struct task_struct *gh_owner = NULL; 1656 char flags_buf[32]; 1657 1658 if (gh->gh_owner_pid) 1659 gh_owner = pid_task(gh->gh_owner_pid, PIDTYPE_PID); 1660 gfs2_print_dbg(seq, " H: s:%s f:%s e:%d p:%ld [%s] %pS\n", 1661 state2str(gh->gh_state), 1662 hflags2str(flags_buf, gh->gh_flags, gh->gh_iflags), 1663 gh->gh_error, 1664 gh->gh_owner_pid ? (long)pid_nr(gh->gh_owner_pid) : -1, 1665 gh_owner ? gh_owner->comm : "(ended)", 1666 (void *)gh->gh_ip); 1667 return 0; 1668 } 1669 1670 static const char *gflags2str(char *buf, const struct gfs2_glock *gl) 1671 { 1672 const unsigned long *gflags = &gl->gl_flags; 1673 char *p = buf; 1674 1675 if (test_bit(GLF_LOCK, gflags)) 1676 *p++ = 'l'; 1677 if (test_bit(GLF_DEMOTE, gflags)) 1678 *p++ = 'D'; 1679 if (test_bit(GLF_PENDING_DEMOTE, gflags)) 1680 *p++ = 'd'; 1681 if (test_bit(GLF_DEMOTE_IN_PROGRESS, gflags)) 1682 *p++ = 'p'; 1683 if (test_bit(GLF_DIRTY, gflags)) 1684 *p++ = 'y'; 1685 if (test_bit(GLF_LFLUSH, gflags)) 1686 *p++ = 'f'; 1687 if (test_bit(GLF_INVALIDATE_IN_PROGRESS, gflags)) 1688 *p++ = 'i'; 1689 if (test_bit(GLF_REPLY_PENDING, gflags)) 1690 *p++ = 'r'; 1691 if (test_bit(GLF_INITIAL, gflags)) 1692 *p++ = 'I'; 1693 if (test_bit(GLF_FROZEN, gflags)) 1694 *p++ = 'F'; 1695 if (test_bit(GLF_QUEUED, gflags)) 1696 *p++ = 'q'; 1697 if (test_bit(GLF_LRU, gflags)) 1698 *p++ = 'L'; 1699 if (gl->gl_object) 1700 *p++ = 'o'; 1701 if (test_bit(GLF_BLOCKING, gflags)) 1702 *p++ = 'b'; 1703 *p = 0; 1704 return buf; 1705 } 1706 1707 /** 1708 * gfs2_dump_glock - print information about a glock 1709 * @seq: The seq_file struct 1710 * @gl: the glock 1711 * 1712 * The file format is as follows: 1713 * One line per object, capital letters are used to indicate objects 1714 * G = glock, I = Inode, R = rgrp, H = holder. Glocks are not indented, 1715 * other objects are indented by a single space and follow the glock to 1716 * which they are related. Fields are indicated by lower case letters 1717 * followed by a colon and the field value, except for strings which are in 1718 * [] so that its possible to see if they are composed of spaces for 1719 * example. The field's are n = number (id of the object), f = flags, 1720 * t = type, s = state, r = refcount, e = error, p = pid. 1721 * 1722 * Returns: 0 on success, -ENOBUFS when we run out of space 1723 */ 1724 1725 int gfs2_dump_glock(struct seq_file *seq, const struct gfs2_glock *gl) 1726 { 1727 const struct gfs2_glock_operations *glops = gl->gl_ops; 1728 unsigned long long dtime; 1729 const struct gfs2_holder *gh; 1730 char gflags_buf[32]; 1731 int error = 0; 1732 1733 dtime = jiffies - gl->gl_demote_time; 1734 dtime *= 1000000/HZ; /* demote time in uSec */ 1735 if (!test_bit(GLF_DEMOTE, &gl->gl_flags)) 1736 dtime = 0; 1737 gfs2_print_dbg(seq, "G: s:%s n:%u/%llx f:%s t:%s d:%s/%llu a:%d v:%d r:%d m:%ld\n", 1738 state2str(gl->gl_state), 1739 gl->gl_name.ln_type, 1740 (unsigned long long)gl->gl_name.ln_number, 1741 gflags2str(gflags_buf, gl), 1742 state2str(gl->gl_target), 1743 state2str(gl->gl_demote_state), dtime, 1744 atomic_read(&gl->gl_ail_count), 1745 atomic_read(&gl->gl_revokes), 1746 (int)gl->gl_lockref.count, gl->gl_hold_time); 1747 1748 list_for_each_entry(gh, &gl->gl_holders, gh_list) { 1749 error = dump_holder(seq, gh); 1750 if (error) 1751 goto out; 1752 } 1753 if (gl->gl_state != LM_ST_UNLOCKED && glops->go_dump) 1754 error = glops->go_dump(seq, gl); 1755 out: 1756 return error; 1757 } 1758 1759 static int gfs2_glstats_seq_show(struct seq_file *seq, void *iter_ptr) 1760 { 1761 struct gfs2_glock *gl = iter_ptr; 1762 1763 seq_printf(seq, "G: n:%u/%llx rtt:%lld/%lld rttb:%lld/%lld irt:%lld/%lld dcnt: %lld qcnt: %lld\n", 1764 gl->gl_name.ln_type, 1765 (unsigned long long)gl->gl_name.ln_number, 1766 (long long)gl->gl_stats.stats[GFS2_LKS_SRTT], 1767 (long long)gl->gl_stats.stats[GFS2_LKS_SRTTVAR], 1768 (long long)gl->gl_stats.stats[GFS2_LKS_SRTTB], 1769 (long long)gl->gl_stats.stats[GFS2_LKS_SRTTVARB], 1770 (long long)gl->gl_stats.stats[GFS2_LKS_SIRT], 1771 (long long)gl->gl_stats.stats[GFS2_LKS_SIRTVAR], 1772 (long long)gl->gl_stats.stats[GFS2_LKS_DCOUNT], 1773 (long long)gl->gl_stats.stats[GFS2_LKS_QCOUNT]); 1774 return 0; 1775 } 1776 1777 static const char *gfs2_gltype[] = { 1778 "type", 1779 "reserved", 1780 "nondisk", 1781 "inode", 1782 "rgrp", 1783 "meta", 1784 "iopen", 1785 "flock", 1786 "plock", 1787 "quota", 1788 "journal", 1789 }; 1790 1791 static const char *gfs2_stype[] = { 1792 [GFS2_LKS_SRTT] = "srtt", 1793 [GFS2_LKS_SRTTVAR] = "srttvar", 1794 [GFS2_LKS_SRTTB] = "srttb", 1795 [GFS2_LKS_SRTTVARB] = "srttvarb", 1796 [GFS2_LKS_SIRT] = "sirt", 1797 [GFS2_LKS_SIRTVAR] = "sirtvar", 1798 [GFS2_LKS_DCOUNT] = "dlm", 1799 [GFS2_LKS_QCOUNT] = "queue", 1800 }; 1801 1802 #define GFS2_NR_SBSTATS (ARRAY_SIZE(gfs2_gltype) * ARRAY_SIZE(gfs2_stype)) 1803 1804 static int gfs2_sbstats_seq_show(struct seq_file *seq, void *iter_ptr) 1805 { 1806 struct gfs2_glock_iter *gi = seq->private; 1807 struct gfs2_sbd *sdp = gi->sdp; 1808 unsigned index = gi->hash >> 3; 1809 unsigned subindex = gi->hash & 0x07; 1810 s64 value; 1811 int i; 1812 1813 if (index == 0 && subindex != 0) 1814 return 0; 1815 1816 seq_printf(seq, "%-10s %8s:", gfs2_gltype[index], 1817 (index == 0) ? "cpu": gfs2_stype[subindex]); 1818 1819 for_each_possible_cpu(i) { 1820 const struct gfs2_pcpu_lkstats *lkstats = per_cpu_ptr(sdp->sd_lkstats, i); 1821 if (index == 0) { 1822 value = i; 1823 } else { 1824 value = lkstats->lkstats[index - 1].stats[subindex]; 1825 } 1826 seq_printf(seq, " %15lld", (long long)value); 1827 } 1828 seq_putc(seq, '\n'); 1829 return 0; 1830 } 1831 1832 int __init gfs2_glock_init(void) 1833 { 1834 unsigned i; 1835 for(i = 0; i < GFS2_GL_HASH_SIZE; i++) { 1836 INIT_HLIST_BL_HEAD(&gl_hash_table[i]); 1837 } 1838 1839 glock_workqueue = alloc_workqueue("glock_workqueue", WQ_MEM_RECLAIM | 1840 WQ_HIGHPRI | WQ_FREEZABLE, 0); 1841 if (!glock_workqueue) 1842 return -ENOMEM; 1843 gfs2_delete_workqueue = alloc_workqueue("delete_workqueue", 1844 WQ_MEM_RECLAIM | WQ_FREEZABLE, 1845 0); 1846 if (!gfs2_delete_workqueue) { 1847 destroy_workqueue(glock_workqueue); 1848 return -ENOMEM; 1849 } 1850 1851 register_shrinker(&glock_shrinker); 1852 1853 return 0; 1854 } 1855 1856 void gfs2_glock_exit(void) 1857 { 1858 unregister_shrinker(&glock_shrinker); 1859 destroy_workqueue(glock_workqueue); 1860 destroy_workqueue(gfs2_delete_workqueue); 1861 } 1862 1863 static inline struct gfs2_glock *glock_hash_chain(unsigned hash) 1864 { 1865 return hlist_bl_entry(hlist_bl_first_rcu(&gl_hash_table[hash]), 1866 struct gfs2_glock, gl_list); 1867 } 1868 1869 static inline struct gfs2_glock *glock_hash_next(struct gfs2_glock *gl) 1870 { 1871 return hlist_bl_entry(rcu_dereference(gl->gl_list.next), 1872 struct gfs2_glock, gl_list); 1873 } 1874 1875 static int gfs2_glock_iter_next(struct gfs2_glock_iter *gi) 1876 { 1877 struct gfs2_glock *gl; 1878 1879 do { 1880 gl = gi->gl; 1881 if (gl) { 1882 gi->gl = glock_hash_next(gl); 1883 gi->nhash++; 1884 } else { 1885 if (gi->hash >= GFS2_GL_HASH_SIZE) { 1886 rcu_read_unlock(); 1887 return 1; 1888 } 1889 gi->gl = glock_hash_chain(gi->hash); 1890 gi->nhash = 0; 1891 } 1892 while (gi->gl == NULL) { 1893 gi->hash++; 1894 if (gi->hash >= GFS2_GL_HASH_SIZE) { 1895 rcu_read_unlock(); 1896 return 1; 1897 } 1898 gi->gl = glock_hash_chain(gi->hash); 1899 gi->nhash = 0; 1900 } 1901 /* Skip entries for other sb and dead entries */ 1902 } while (gi->sdp != gi->gl->gl_sbd || 1903 __lockref_is_dead(&gi->gl->gl_lockref)); 1904 1905 return 0; 1906 } 1907 1908 static void *gfs2_glock_seq_start(struct seq_file *seq, loff_t *pos) 1909 { 1910 struct gfs2_glock_iter *gi = seq->private; 1911 loff_t n = *pos; 1912 1913 if (gi->last_pos <= *pos) 1914 n = gi->nhash + (*pos - gi->last_pos); 1915 else 1916 gi->hash = 0; 1917 1918 gi->nhash = 0; 1919 rcu_read_lock(); 1920 1921 do { 1922 if (gfs2_glock_iter_next(gi)) 1923 return NULL; 1924 } while (n--); 1925 1926 gi->last_pos = *pos; 1927 return gi->gl; 1928 } 1929 1930 static void *gfs2_glock_seq_next(struct seq_file *seq, void *iter_ptr, 1931 loff_t *pos) 1932 { 1933 struct gfs2_glock_iter *gi = seq->private; 1934 1935 (*pos)++; 1936 gi->last_pos = *pos; 1937 if (gfs2_glock_iter_next(gi)) 1938 return NULL; 1939 1940 return gi->gl; 1941 } 1942 1943 static void gfs2_glock_seq_stop(struct seq_file *seq, void *iter_ptr) 1944 { 1945 struct gfs2_glock_iter *gi = seq->private; 1946 1947 if (gi->gl) 1948 rcu_read_unlock(); 1949 gi->gl = NULL; 1950 } 1951 1952 static int gfs2_glock_seq_show(struct seq_file *seq, void *iter_ptr) 1953 { 1954 return dump_glock(seq, iter_ptr); 1955 } 1956 1957 static void *gfs2_sbstats_seq_start(struct seq_file *seq, loff_t *pos) 1958 { 1959 struct gfs2_glock_iter *gi = seq->private; 1960 1961 gi->hash = *pos; 1962 if (*pos >= GFS2_NR_SBSTATS) 1963 return NULL; 1964 preempt_disable(); 1965 return SEQ_START_TOKEN; 1966 } 1967 1968 static void *gfs2_sbstats_seq_next(struct seq_file *seq, void *iter_ptr, 1969 loff_t *pos) 1970 { 1971 struct gfs2_glock_iter *gi = seq->private; 1972 (*pos)++; 1973 gi->hash++; 1974 if (gi->hash >= GFS2_NR_SBSTATS) { 1975 preempt_enable(); 1976 return NULL; 1977 } 1978 return SEQ_START_TOKEN; 1979 } 1980 1981 static void gfs2_sbstats_seq_stop(struct seq_file *seq, void *iter_ptr) 1982 { 1983 preempt_enable(); 1984 } 1985 1986 static const struct seq_operations gfs2_glock_seq_ops = { 1987 .start = gfs2_glock_seq_start, 1988 .next = gfs2_glock_seq_next, 1989 .stop = gfs2_glock_seq_stop, 1990 .show = gfs2_glock_seq_show, 1991 }; 1992 1993 static const struct seq_operations gfs2_glstats_seq_ops = { 1994 .start = gfs2_glock_seq_start, 1995 .next = gfs2_glock_seq_next, 1996 .stop = gfs2_glock_seq_stop, 1997 .show = gfs2_glstats_seq_show, 1998 }; 1999 2000 static const struct seq_operations gfs2_sbstats_seq_ops = { 2001 .start = gfs2_sbstats_seq_start, 2002 .next = gfs2_sbstats_seq_next, 2003 .stop = gfs2_sbstats_seq_stop, 2004 .show = gfs2_sbstats_seq_show, 2005 }; 2006 2007 #define GFS2_SEQ_GOODSIZE min(PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER, 65536UL) 2008 2009 static int gfs2_glocks_open(struct inode *inode, struct file *file) 2010 { 2011 int ret = seq_open_private(file, &gfs2_glock_seq_ops, 2012 sizeof(struct gfs2_glock_iter)); 2013 if (ret == 0) { 2014 struct seq_file *seq = file->private_data; 2015 struct gfs2_glock_iter *gi = seq->private; 2016 gi->sdp = inode->i_private; 2017 seq->buf = kmalloc(GFS2_SEQ_GOODSIZE, GFP_KERNEL | __GFP_NOWARN); 2018 if (seq->buf) 2019 seq->size = GFS2_SEQ_GOODSIZE; 2020 } 2021 return ret; 2022 } 2023 2024 static int gfs2_glstats_open(struct inode *inode, struct file *file) 2025 { 2026 int ret = seq_open_private(file, &gfs2_glstats_seq_ops, 2027 sizeof(struct gfs2_glock_iter)); 2028 if (ret == 0) { 2029 struct seq_file *seq = file->private_data; 2030 struct gfs2_glock_iter *gi = seq->private; 2031 gi->sdp = inode->i_private; 2032 seq->buf = kmalloc(GFS2_SEQ_GOODSIZE, GFP_KERNEL | __GFP_NOWARN); 2033 if (seq->buf) 2034 seq->size = GFS2_SEQ_GOODSIZE; 2035 } 2036 return ret; 2037 } 2038 2039 static int gfs2_sbstats_open(struct inode *inode, struct file *file) 2040 { 2041 int ret = seq_open_private(file, &gfs2_sbstats_seq_ops, 2042 sizeof(struct gfs2_glock_iter)); 2043 if (ret == 0) { 2044 struct seq_file *seq = file->private_data; 2045 struct gfs2_glock_iter *gi = seq->private; 2046 gi->sdp = inode->i_private; 2047 } 2048 return ret; 2049 } 2050 2051 static const struct file_operations gfs2_glocks_fops = { 2052 .owner = THIS_MODULE, 2053 .open = gfs2_glocks_open, 2054 .read = seq_read, 2055 .llseek = seq_lseek, 2056 .release = seq_release_private, 2057 }; 2058 2059 static const struct file_operations gfs2_glstats_fops = { 2060 .owner = THIS_MODULE, 2061 .open = gfs2_glstats_open, 2062 .read = seq_read, 2063 .llseek = seq_lseek, 2064 .release = seq_release_private, 2065 }; 2066 2067 static const struct file_operations gfs2_sbstats_fops = { 2068 .owner = THIS_MODULE, 2069 .open = gfs2_sbstats_open, 2070 .read = seq_read, 2071 .llseek = seq_lseek, 2072 .release = seq_release_private, 2073 }; 2074 2075 int gfs2_create_debugfs_file(struct gfs2_sbd *sdp) 2076 { 2077 sdp->debugfs_dir = debugfs_create_dir(sdp->sd_table_name, gfs2_root); 2078 if (!sdp->debugfs_dir) 2079 return -ENOMEM; 2080 sdp->debugfs_dentry_glocks = debugfs_create_file("glocks", 2081 S_IFREG | S_IRUGO, 2082 sdp->debugfs_dir, sdp, 2083 &gfs2_glocks_fops); 2084 if (!sdp->debugfs_dentry_glocks) 2085 goto fail; 2086 2087 sdp->debugfs_dentry_glstats = debugfs_create_file("glstats", 2088 S_IFREG | S_IRUGO, 2089 sdp->debugfs_dir, sdp, 2090 &gfs2_glstats_fops); 2091 if (!sdp->debugfs_dentry_glstats) 2092 goto fail; 2093 2094 sdp->debugfs_dentry_sbstats = debugfs_create_file("sbstats", 2095 S_IFREG | S_IRUGO, 2096 sdp->debugfs_dir, sdp, 2097 &gfs2_sbstats_fops); 2098 if (!sdp->debugfs_dentry_sbstats) 2099 goto fail; 2100 2101 return 0; 2102 fail: 2103 gfs2_delete_debugfs_file(sdp); 2104 return -ENOMEM; 2105 } 2106 2107 void gfs2_delete_debugfs_file(struct gfs2_sbd *sdp) 2108 { 2109 if (sdp->debugfs_dir) { 2110 if (sdp->debugfs_dentry_glocks) { 2111 debugfs_remove(sdp->debugfs_dentry_glocks); 2112 sdp->debugfs_dentry_glocks = NULL; 2113 } 2114 if (sdp->debugfs_dentry_glstats) { 2115 debugfs_remove(sdp->debugfs_dentry_glstats); 2116 sdp->debugfs_dentry_glstats = NULL; 2117 } 2118 if (sdp->debugfs_dentry_sbstats) { 2119 debugfs_remove(sdp->debugfs_dentry_sbstats); 2120 sdp->debugfs_dentry_sbstats = NULL; 2121 } 2122 debugfs_remove(sdp->debugfs_dir); 2123 sdp->debugfs_dir = NULL; 2124 } 2125 } 2126 2127 int gfs2_register_debugfs(void) 2128 { 2129 gfs2_root = debugfs_create_dir("gfs2", NULL); 2130 return gfs2_root ? 0 : -ENOMEM; 2131 } 2132 2133 void gfs2_unregister_debugfs(void) 2134 { 2135 debugfs_remove(gfs2_root); 2136 gfs2_root = NULL; 2137 } 2138