fs/gfs2/glock.c

   1 /*
   2  * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
   3  * Copyright (C) 2004-2006 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/completion.h>
  14 #include <linux/buffer_head.h>
  15 #include <linux/delay.h>
  16 #include <linux/sort.h>
  17 #include <linux/jhash.h>
  18 #include <linux/kref.h>
  19 #include <linux/kallsyms.h>
  20 #include <linux/gfs2_ondisk.h>
  21 #include <asm/uaccess.h>
  22
  23 #include "gfs2.h"
  24 #include "lm_interface.h"
  25 #include "incore.h"
  26 #include "glock.h"
  27 #include "glops.h"
  28 #include "inode.h"
  29 #include "lm.h"
  30 #include "lops.h"
  31 #include "meta_io.h"
  32 #include "quota.h"
  33 #include "super.h"
  34 #include "util.h"
  35
  36 /*  Must be kept in sync with the beginning of struct gfs2_glock  */
  37 struct glock_plug {
  38         struct list_head gl_list;
  39         unsigned long gl_flags;
  40 };
  41
  42 struct greedy {
  43         struct gfs2_holder gr_gh;
  44         struct work_struct gr_work;
  45 };
  46
  47 struct gfs2_gl_hash_bucket {
  48         struct list_head hb_list;
  49 };
  50
  51 typedef void (*glock_examiner) (struct gfs2_glock * gl);
  52
  53 static int gfs2_dump_lockstate(struct gfs2_sbd *sdp);
  54 static int dump_glock(struct gfs2_glock *gl);
  55
  56 static struct gfs2_gl_hash_bucket gl_hash_table[GFS2_GL_HASH_SIZE];
  57 static rwlock_t gl_hash_locks[GFS2_GL_HASH_SIZE];
  58
  59 /**
  60  * relaxed_state_ok - is a requested lock compatible with the current lock mode?
  61  * @actual: the current state of the lock
  62  * @requested: the lock state that was requested by the caller
  63  * @flags: the modifier flags passed in by the caller
  64  *
  65  * Returns: 1 if the locks are compatible, 0 otherwise
  66  */
  67
  68 static inline int relaxed_state_ok(unsigned int actual, unsigned requested,
  69                                    int flags)
  70 {
  71         if (actual == requested)
  72                 return 1;
  73
  74         if (flags & GL_EXACT)
  75                 return 0;
  76
  77         if (actual == LM_ST_EXCLUSIVE && requested == LM_ST_SHARED)
  78                 return 1;
  79
  80         if (actual != LM_ST_UNLOCKED && (flags & LM_FLAG_ANY))
  81                 return 1;
  82
  83         return 0;
  84 }
  85
  86 /**
  87  * gl_hash() - Turn glock number into hash bucket number
  88  * @lock: The glock number
  89  *
  90  * Returns: The number of the corresponding hash bucket
  91  */
  92
  93 static unsigned int gl_hash(const struct gfs2_sbd *sdp,
  94                             const struct lm_lockname *name)
  95 {
  96         unsigned int h;
  97
  98         h = jhash(&name->ln_number, sizeof(u64), 0);
  99         h = jhash(&name->ln_type, sizeof(unsigned int), h);
 100         h = jhash(&sdp, sizeof(struct gfs2_sbd *), h);
 101         h &= GFS2_GL_HASH_MASK;
 102
 103         return h;
 104 }
 105
 106 /**
 107  * glock_free() - Perform a few checks and then release struct gfs2_glock
 108  * @gl: The glock to release
 109  *
 110  * Also calls lock module to release its internal structure for this glock.
 111  *
 112  */
 113
 114 static void glock_free(struct gfs2_glock *gl)
 115 {
 116         struct gfs2_sbd *sdp = gl->gl_sbd;
 117         struct inode *aspace = gl->gl_aspace;
 118
 119         gfs2_lm_put_lock(sdp, gl->gl_lock);
 120
 121         if (aspace)
 122                 gfs2_aspace_put(aspace);
 123
 124         kmem_cache_free(gfs2_glock_cachep, gl);
 125 }
 126
 127 /**
 128  * gfs2_glock_hold() - increment reference count on glock
 129  * @gl: The glock to hold
 130  *
 131  */
 132
 133 void gfs2_glock_hold(struct gfs2_glock *gl)
 134 {
 135         kref_get(&gl->gl_ref);
 136 }
 137
 138 /* All work is done after the return from kref_put() so we
 139    can release the write_lock before the free. */
 140
 141 static void kill_glock(struct kref *kref)
 142 {
 143         struct gfs2_glock *gl = container_of(kref, struct gfs2_glock, gl_ref);
 144         struct gfs2_sbd *sdp = gl->gl_sbd;
 145
 146         gfs2_assert(sdp, gl->gl_state == LM_ST_UNLOCKED);
 147         gfs2_assert(sdp, list_empty(&gl->gl_reclaim));
 148         gfs2_assert(sdp, list_empty(&gl->gl_holders));
 149         gfs2_assert(sdp, list_empty(&gl->gl_waiters1));
 150         gfs2_assert(sdp, list_empty(&gl->gl_waiters2));
 151         gfs2_assert(sdp, list_empty(&gl->gl_waiters3));
 152 }
 153
 154 /**
 155  * gfs2_glock_put() - Decrement reference count on glock
 156  * @gl: The glock to put
 157  *
 158  */
 159
 160 int gfs2_glock_put(struct gfs2_glock *gl)
 161 {
 162         int rv = 0;
 163
 164         write_lock(&gl_hash_locks[gl->gl_hash]);
 165         if (kref_put(&gl->gl_ref, kill_glock)) {
 166                 list_del_init(&gl_hash_table[gl->gl_hash].hb_list);
 167                 write_unlock(&gl_hash_locks[gl->gl_hash]);
 168                 BUG_ON(spin_is_locked(&gl->gl_spin));
 169                 glock_free(gl);
 170                 rv = 1;
 171                 goto out;
 172         }
 173         write_unlock(&gl_hash_locks[gl->gl_hash]);
 174 out:
 175         return rv;
 176 }
 177
 178 /**
 179  * queue_empty - check to see if a glock's queue is empty
 180  * @gl: the glock
 181  * @head: the head of the queue to check
 182  *
 183  * This function protects the list in the event that a process already
 184  * has a holder on the list and is adding a second holder for itself.
 185  * The glmutex lock is what generally prevents processes from working
 186  * on the same glock at once, but the special case of adding a second
 187  * holder for yourself ("recursive" locking) doesn't involve locking
 188  * glmutex, making the spin lock necessary.
 189  *
 190  * Returns: 1 if the queue is empty
 191  */
 192
 193 static inline int queue_empty(struct gfs2_glock *gl, struct list_head *head)
 194 {
 195         int empty;
 196         spin_lock(&gl->gl_spin);
 197         empty = list_empty(head);
 198         spin_unlock(&gl->gl_spin);
 199         return empty;
 200 }
 201
 202 /**
 203  * search_bucket() - Find struct gfs2_glock by lock number
 204  * @bucket: the bucket to search
 205  * @name: The lock name
 206  *
 207  * Returns: NULL, or the struct gfs2_glock with the requested number
 208  */
 209
 210 static struct gfs2_glock *search_bucket(unsigned int hash,
 211                                         const struct gfs2_sbd *sdp,
 212                                         const struct lm_lockname *name)
 213 {
 214         struct gfs2_glock *gl;
 215
 216         list_for_each_entry(gl, &gl_hash_table[hash].hb_list, gl_list) {
 217                 if (test_bit(GLF_PLUG, &gl->gl_flags))
 218                         continue;
 219                 if (!lm_name_equal(&gl->gl_name, name))
 220                         continue;
 221                 if (gl->gl_sbd != sdp)
 222                         continue;
 223
 224                 kref_get(&gl->gl_ref);
 225
 226                 return gl;
 227         }
 228
 229         return NULL;
 230 }
 231
 232 /**
 233  * gfs2_glock_find() - Find glock by lock number
 234  * @sdp: The GFS2 superblock
 235  * @name: The lock name
 236  *
 237  * Returns: NULL, or the struct gfs2_glock with the requested number
 238  */
 239
 240 static struct gfs2_glock *gfs2_glock_find(const struct gfs2_sbd *sdp,
 241                                           const struct lm_lockname *name)
 242 {
 243         unsigned int hash = gl_hash(sdp, name);
 244         struct gfs2_glock *gl;
 245
 246         read_lock(&gl_hash_locks[hash]);
 247         gl = search_bucket(hash, sdp, name);
 248         read_unlock(&gl_hash_locks[hash]);
 249
 250         return gl;
 251 }
 252
 253 /**
 254  * gfs2_glock_get() - Get a glock, or create one if one doesn't exist
 255  * @sdp: The GFS2 superblock
 256  * @number: the lock number
 257  * @glops: The glock_operations to use
 258  * @create: If 0, don't create the glock if it doesn't exist
 259  * @glp: the glock is returned here
 260  *
 261  * This does not lock a glock, just finds/creates structures for one.
 262  *
 263  * Returns: errno
 264  */
 265
 266 int gfs2_glock_get(struct gfs2_sbd *sdp, u64 number,
 267                    const struct gfs2_glock_operations *glops, int create,
 268                    struct gfs2_glock **glp)
 269 {
 270         struct lm_lockname name = { .ln_number = number, .ln_type = glops->go_type };
 271         struct gfs2_glock *gl, *tmp;
 272         unsigned int hash = gl_hash(sdp, &name);
 273         int error;
 274
 275         read_lock(&gl_hash_locks[hash]);
 276         gl = search_bucket(hash, sdp, &name);
 277         read_unlock(&gl_hash_locks[hash]);
 278
 279         if (gl || !create) {
 280                 *glp = gl;
 281                 return 0;
 282         }
 283
 284         gl = kmem_cache_alloc(gfs2_glock_cachep, GFP_KERNEL);
 285         if (!gl)
 286                 return -ENOMEM;
 287
 288         gl->gl_flags = 0;
 289         gl->gl_name = name;
 290         kref_init(&gl->gl_ref);
 291         gl->gl_state = LM_ST_UNLOCKED;
 292         gl->gl_hash = hash;
 293         gl->gl_owner = NULL;
 294         gl->gl_ip = 0;
 295         gl->gl_ops = glops;
 296         gl->gl_req_gh = NULL;
 297         gl->gl_req_bh = NULL;
 298         gl->gl_vn = 0;
 299         gl->gl_stamp = jiffies;
 300         gl->gl_object = NULL;
 301         gl->gl_sbd = sdp;
 302         gl->gl_aspace = NULL;
 303         lops_init_le(&gl->gl_le, &gfs2_glock_lops);
 304
 305         /* If this glock protects actual on-disk data or metadata blocks,
 306            create a VFS inode to manage the pages/buffers holding them. */
 307         if (glops == &gfs2_inode_glops || glops == &gfs2_rgrp_glops) {
 308                 gl->gl_aspace = gfs2_aspace_get(sdp);
 309                 if (!gl->gl_aspace) {
 310                         error = -ENOMEM;
 311                         goto fail;
 312                 }
 313         }
 314
 315         error = gfs2_lm_get_lock(sdp, &name, &gl->gl_lock);
 316         if (error)
 317                 goto fail_aspace;
 318
 319         write_lock(&gl_hash_locks[hash]);
 320         tmp = search_bucket(hash, sdp, &name);
 321         if (tmp) {
 322                 write_unlock(&gl_hash_locks[hash]);
 323                 glock_free(gl);
 324                 gl = tmp;
 325         } else {
 326                 list_add_tail(&gl->gl_list, &gl_hash_table[hash].hb_list);
 327                 write_unlock(&gl_hash_locks[hash]);
 328         }
 329
 330         *glp = gl;
 331
 332         return 0;
 333
 334 fail_aspace:
 335         if (gl->gl_aspace)
 336                 gfs2_aspace_put(gl->gl_aspace);
 337 fail:
 338         kmem_cache_free(gfs2_glock_cachep, gl);
 339         return error;
 340 }
 341
 342 /**
 343  * gfs2_holder_init - initialize a struct gfs2_holder in the default way
 344  * @gl: the glock
 345  * @state: the state we're requesting
 346  * @flags: the modifier flags
 347  * @gh: the holder structure
 348  *
 349  */
 350
 351 void gfs2_holder_init(struct gfs2_glock *gl, unsigned int state, unsigned flags,
 352                       struct gfs2_holder *gh)
 353 {
 354         INIT_LIST_HEAD(&gh->gh_list);
 355         gh->gh_gl = gl;
 356         gh->gh_ip = (unsigned long)__builtin_return_address(0);
 357         gh->gh_owner = current;
 358         gh->gh_state = state;
 359         gh->gh_flags = flags;
 360         gh->gh_error = 0;
 361         gh->gh_iflags = 0;
 362         init_completion(&gh->gh_wait);
 363
 364         if (gh->gh_state == LM_ST_EXCLUSIVE)
 365                 gh->gh_flags |= GL_LOCAL_EXCL;
 366
 367         gfs2_glock_hold(gl);
 368 }
 369
 370 /**
 371  * gfs2_holder_reinit - reinitialize a struct gfs2_holder so we can requeue it
 372  * @state: the state we're requesting
 373  * @flags: the modifier flags
 374  * @gh: the holder structure
 375  *
 376  * Don't mess with the glock.
 377  *
 378  */
 379
 380 void gfs2_holder_reinit(unsigned int state, unsigned flags, struct gfs2_holder *gh)
 381 {
 382         gh->gh_state = state;
 383         gh->gh_flags = flags;
 384         if (gh->gh_state == LM_ST_EXCLUSIVE)
 385                 gh->gh_flags |= GL_LOCAL_EXCL;
 386
 387         gh->gh_iflags &= 1 << HIF_ALLOCED;
 388         gh->gh_ip = (unsigned long)__builtin_return_address(0);
 389 }
 390
 391 /**
 392  * gfs2_holder_uninit - uninitialize a holder structure (drop glock reference)
 393  * @gh: the holder structure
 394  *
 395  */
 396
 397 void gfs2_holder_uninit(struct gfs2_holder *gh)
 398 {
 399         gfs2_glock_put(gh->gh_gl);
 400         gh->gh_gl = NULL;
 401         gh->gh_ip = 0;
 402 }
 403
 404 /**
 405  * gfs2_holder_get - get a struct gfs2_holder structure
 406  * @gl: the glock
 407  * @state: the state we're requesting
 408  * @flags: the modifier flags
 409  * @gfp_flags:
 410  *
 411  * Figure out how big an impact this function has.  Either:
 412  * 1) Replace it with a cache of structures hanging off the struct gfs2_sbd
 413  * 2) Leave it like it is
 414  *
 415  * Returns: the holder structure, NULL on ENOMEM
 416  */
 417
 418 static struct gfs2_holder *gfs2_holder_get(struct gfs2_glock *gl,
 419                                            unsigned int state,
 420                                            int flags, gfp_t gfp_flags)
 421 {
 422         struct gfs2_holder *gh;
 423
 424         gh = kmalloc(sizeof(struct gfs2_holder), gfp_flags);
 425         if (!gh)
 426                 return NULL;
 427
 428         gfs2_holder_init(gl, state, flags, gh);
 429         set_bit(HIF_ALLOCED, &gh->gh_iflags);
 430         gh->gh_ip = (unsigned long)__builtin_return_address(0);
 431         return gh;
 432 }
 433
 434 /**
 435  * gfs2_holder_put - get rid of a struct gfs2_holder structure
 436  * @gh: the holder structure
 437  *
 438  */
 439
 440 static void gfs2_holder_put(struct gfs2_holder *gh)
 441 {
 442         gfs2_holder_uninit(gh);
 443         kfree(gh);
 444 }
 445
 446 /**
 447  * rq_mutex - process a mutex request in the queue
 448  * @gh: the glock holder
 449  *
 450  * Returns: 1 if the queue is blocked
 451  */
 452
 453 static int rq_mutex(struct gfs2_holder *gh)
 454 {
 455         struct gfs2_glock *gl = gh->gh_gl;
 456
 457         list_del_init(&gh->gh_list);
 458         /*  gh->gh_error never examined.  */
 459         set_bit(GLF_LOCK, &gl->gl_flags);
 460         complete(&gh->gh_wait);
 461
 462         return 1;
 463 }
 464
 465 /**
 466  * rq_promote - process a promote request in the queue
 467  * @gh: the glock holder
 468  *
 469  * Acquire a new inter-node lock, or change a lock state to more restrictive.
 470  *
 471  * Returns: 1 if the queue is blocked
 472  */
 473
 474 static int rq_promote(struct gfs2_holder *gh)
 475 {
 476         struct gfs2_glock *gl = gh->gh_gl;
 477         struct gfs2_sbd *sdp = gl->gl_sbd;
 478         const struct gfs2_glock_operations *glops = gl->gl_ops;
 479
 480         if (!relaxed_state_ok(gl->gl_state, gh->gh_state, gh->gh_flags)) {
 481                 if (list_empty(&gl->gl_holders)) {
 482                         gl->gl_req_gh = gh;
 483                         set_bit(GLF_LOCK, &gl->gl_flags);
 484                         spin_unlock(&gl->gl_spin);
 485
 486                         if (atomic_read(&sdp->sd_reclaim_count) >
 487                             gfs2_tune_get(sdp, gt_reclaim_limit) &&
 488                             !(gh->gh_flags & LM_FLAG_PRIORITY)) {
 489                                 gfs2_reclaim_glock(sdp);
 490                                 gfs2_reclaim_glock(sdp);
 491                         }
 492
 493                         glops->go_xmote_th(gl, gh->gh_state, gh->gh_flags);
 494                         spin_lock(&gl->gl_spin);
 495                 }
 496                 return 1;
 497         }
 498
 499         if (list_empty(&gl->gl_holders)) {
 500                 set_bit(HIF_FIRST, &gh->gh_iflags);
 501                 set_bit(GLF_LOCK, &gl->gl_flags);
 502         } else {
 503                 struct gfs2_holder *next_gh;
 504                 if (gh->gh_flags & GL_LOCAL_EXCL)
 505                         return 1;
 506                 next_gh = list_entry(gl->gl_holders.next, struct gfs2_holder,
 507                                      gh_list);
 508                 if (next_gh->gh_flags & GL_LOCAL_EXCL)
 509                          return 1;
 510         }
 511
 512         list_move_tail(&gh->gh_list, &gl->gl_holders);
 513         gh->gh_error = 0;
 514         set_bit(HIF_HOLDER, &gh->gh_iflags);
 515
 516         complete(&gh->gh_wait);
 517
 518         return 0;
 519 }
 520
 521 /**
 522  * rq_demote - process a demote request in the queue
 523  * @gh: the glock holder
 524  *
 525  * Returns: 1 if the queue is blocked
 526  */
 527
 528 static int rq_demote(struct gfs2_holder *gh)
 529 {
 530         struct gfs2_glock *gl = gh->gh_gl;
 531         const struct gfs2_glock_operations *glops = gl->gl_ops;
 532
 533         if (!list_empty(&gl->gl_holders))
 534                 return 1;
 535
 536         if (gl->gl_state == gh->gh_state || gl->gl_state == LM_ST_UNLOCKED) {
 537                 list_del_init(&gh->gh_list);
 538                 gh->gh_error = 0;
 539                 spin_unlock(&gl->gl_spin);
 540                 if (test_bit(HIF_DEALLOC, &gh->gh_iflags))
 541                         gfs2_holder_put(gh);
 542                 else
 543                         complete(&gh->gh_wait);
 544                 spin_lock(&gl->gl_spin);
 545         } else {
 546                 gl->gl_req_gh = gh;
 547                 set_bit(GLF_LOCK, &gl->gl_flags);
 548                 spin_unlock(&gl->gl_spin);
 549
 550                 if (gh->gh_state == LM_ST_UNLOCKED ||
 551                     gl->gl_state != LM_ST_EXCLUSIVE)
 552                         glops->go_drop_th(gl);
 553                 else
 554                         glops->go_xmote_th(gl, gh->gh_state, gh->gh_flags);
 555
 556                 spin_lock(&gl->gl_spin);
 557         }
 558
 559         return 0;
 560 }
 561
 562 /**
 563  * rq_greedy - process a queued request to drop greedy status
 564  * @gh: the glock holder
 565  *
 566  * Returns: 1 if the queue is blocked
 567  */
 568
 569 static int rq_greedy(struct gfs2_holder *gh)
 570 {
 571         struct gfs2_glock *gl = gh->gh_gl;
 572
 573         list_del_init(&gh->gh_list);
 574         /*  gh->gh_error never examined.  */
 575         clear_bit(GLF_GREEDY, &gl->gl_flags);
 576         spin_unlock(&gl->gl_spin);
 577
 578         gfs2_holder_uninit(gh);
 579         kfree(container_of(gh, struct greedy, gr_gh));
 580
 581         spin_lock(&gl->gl_spin);
 582
 583         return 0;
 584 }
 585
 586 /**
 587  * run_queue - process holder structures on a glock
 588  * @gl: the glock
 589  *
 590  */
 591 static void run_queue(struct gfs2_glock *gl)
 592 {
 593         struct gfs2_holder *gh;
 594         int blocked = 1;
 595
 596         for (;;) {
 597                 if (test_bit(GLF_LOCK, &gl->gl_flags))
 598                         break;
 599
 600                 if (!list_empty(&gl->gl_waiters1)) {
 601                         gh = list_entry(gl->gl_waiters1.next,
 602                                         struct gfs2_holder, gh_list);
 603
 604                         if (test_bit(HIF_MUTEX, &gh->gh_iflags))
 605                                 blocked = rq_mutex(gh);
 606                         else
 607                                 gfs2_assert_warn(gl->gl_sbd, 0);
 608
 609                 } else if (!list_empty(&gl->gl_waiters2) &&
 610                            !test_bit(GLF_SKIP_WAITERS2, &gl->gl_flags)) {
 611                         gh = list_entry(gl->gl_waiters2.next,
 612                                         struct gfs2_holder, gh_list);
 613
 614                         if (test_bit(HIF_DEMOTE, &gh->gh_iflags))
 615                                 blocked = rq_demote(gh);
 616                         else if (test_bit(HIF_GREEDY, &gh->gh_iflags))
 617                                 blocked = rq_greedy(gh);
 618                         else
 619                                 gfs2_assert_warn(gl->gl_sbd, 0);
 620
 621                 } else if (!list_empty(&gl->gl_waiters3)) {
 622                         gh = list_entry(gl->gl_waiters3.next,
 623                                         struct gfs2_holder, gh_list);
 624
 625                         if (test_bit(HIF_PROMOTE, &gh->gh_iflags))
 626                                 blocked = rq_promote(gh);
 627                         else
 628                                 gfs2_assert_warn(gl->gl_sbd, 0);
 629
 630                 } else
 631                         break;
 632
 633                 if (blocked)
 634                         break;
 635         }
 636 }
 637
 638 /**
 639  * gfs2_glmutex_lock - acquire a local lock on a glock
 640  * @gl: the glock
 641  *
 642  * Gives caller exclusive access to manipulate a glock structure.
 643  */
 644
 645 static void gfs2_glmutex_lock(struct gfs2_glock *gl)
 646 {
 647         struct gfs2_holder gh;
 648
 649         gfs2_holder_init(gl, 0, 0, &gh);
 650         set_bit(HIF_MUTEX, &gh.gh_iflags);
 651
 652         spin_lock(&gl->gl_spin);
 653         if (test_and_set_bit(GLF_LOCK, &gl->gl_flags)) {
 654                 list_add_tail(&gh.gh_list, &gl->gl_waiters1);
 655         } else {
 656                 gl->gl_owner = current;
 657                 gl->gl_ip = (unsigned long)__builtin_return_address(0);
 658                 complete(&gh.gh_wait);
 659         }
 660         spin_unlock(&gl->gl_spin);
 661
 662         wait_for_completion(&gh.gh_wait);
 663         gfs2_holder_uninit(&gh);
 664 }
 665
 666 /**
 667  * gfs2_glmutex_trylock - try to acquire a local lock on a glock
 668  * @gl: the glock
 669  *
 670  * Returns: 1 if the glock is acquired
 671  */
 672
 673 static int gfs2_glmutex_trylock(struct gfs2_glock *gl)
 674 {
 675         int acquired = 1;
 676
 677         spin_lock(&gl->gl_spin);
 678         if (test_and_set_bit(GLF_LOCK, &gl->gl_flags)) {
 679                 acquired = 0;
 680         } else {
 681                 gl->gl_owner = current;
 682                 gl->gl_ip = (unsigned long)__builtin_return_address(0);
 683         }
 684         spin_unlock(&gl->gl_spin);
 685
 686         return acquired;
 687 }
 688
 689 /**
 690  * gfs2_glmutex_unlock - release a local lock on a glock
 691  * @gl: the glock
 692  *
 693  */
 694
 695 static void gfs2_glmutex_unlock(struct gfs2_glock *gl)
 696 {
 697         spin_lock(&gl->gl_spin);
 698         clear_bit(GLF_LOCK, &gl->gl_flags);
 699         gl->gl_owner = NULL;
 700         gl->gl_ip = 0;
 701         run_queue(gl);
 702         BUG_ON(!spin_is_locked(&gl->gl_spin));
 703         spin_unlock(&gl->gl_spin);
 704 }
 705
 706 /**
 707  * handle_callback - add a demote request to a lock's queue
 708  * @gl: the glock
 709  * @state: the state the caller wants us to change to
 710  *
 711  * Note: This may fail sliently if we are out of memory.
 712  */
 713
 714 static void handle_callback(struct gfs2_glock *gl, unsigned int state)
 715 {
 716         struct gfs2_holder *gh, *new_gh = NULL;
 717
 718 restart:
 719         spin_lock(&gl->gl_spin);
 720
 721         list_for_each_entry(gh, &gl->gl_waiters2, gh_list) {
 722                 if (test_bit(HIF_DEMOTE, &gh->gh_iflags) &&
 723                     gl->gl_req_gh != gh) {
 724                         if (gh->gh_state != state)
 725                                 gh->gh_state = LM_ST_UNLOCKED;
 726                         goto out;
 727                 }
 728         }
 729
 730         if (new_gh) {
 731                 list_add_tail(&new_gh->gh_list, &gl->gl_waiters2);
 732                 new_gh = NULL;
 733         } else {
 734                 spin_unlock(&gl->gl_spin);
 735
 736                 new_gh = gfs2_holder_get(gl, state, LM_FLAG_TRY, GFP_KERNEL);
 737                 if (!new_gh)
 738                         return;
 739                 set_bit(HIF_DEMOTE, &new_gh->gh_iflags);
 740                 set_bit(HIF_DEALLOC, &new_gh->gh_iflags);
 741
 742                 goto restart;
 743         }
 744
 745 out:
 746         spin_unlock(&gl->gl_spin);
 747
 748         if (new_gh)
 749                 gfs2_holder_put(new_gh);
 750 }
 751
 752 void gfs2_glock_inode_squish(struct inode *inode)
 753 {
 754         struct gfs2_holder gh;
 755         struct gfs2_glock *gl = GFS2_I(inode)->i_gl;
 756         gfs2_holder_init(gl, LM_ST_UNLOCKED, 0, &gh);
 757         set_bit(HIF_DEMOTE, &gh.gh_iflags);
 758         spin_lock(&gl->gl_spin);
 759         gfs2_assert(inode->i_sb->s_fs_info, list_empty(&gl->gl_holders));
 760         list_add_tail(&gh.gh_list, &gl->gl_waiters2);
 761         run_queue(gl);
 762         spin_unlock(&gl->gl_spin);
 763         wait_for_completion(&gh.gh_wait);
 764         gfs2_holder_uninit(&gh);
 765 }
 766
 767 /**
 768  * state_change - record that the glock is now in a different state
 769  * @gl: the glock
 770  * @new_state the new state
 771  *
 772  */
 773
 774 static void state_change(struct gfs2_glock *gl, unsigned int new_state)
 775 {
 776         int held1, held2;
 777
 778         held1 = (gl->gl_state != LM_ST_UNLOCKED);
 779         held2 = (new_state != LM_ST_UNLOCKED);
 780
 781         if (held1 != held2) {
 782                 if (held2)
 783                         gfs2_glock_hold(gl);
 784                 else
 785                         gfs2_glock_put(gl);
 786         }
 787
 788         gl->gl_state = new_state;
 789 }
 790
 791 /**
 792  * xmote_bh - Called after the lock module is done acquiring a lock
 793  * @gl: The glock in question
 794  * @ret: the int returned from the lock module
 795  *
 796  */
 797
 798 static void xmote_bh(struct gfs2_glock *gl, unsigned int ret)
 799 {
 800         struct gfs2_sbd *sdp = gl->gl_sbd;
 801         const struct gfs2_glock_operations *glops = gl->gl_ops;
 802         struct gfs2_holder *gh = gl->gl_req_gh;
 803         int prev_state = gl->gl_state;
 804         int op_done = 1;
 805
 806         gfs2_assert_warn(sdp, test_bit(GLF_LOCK, &gl->gl_flags));
 807         gfs2_assert_warn(sdp, queue_empty(gl, &gl->gl_holders));
 808         gfs2_assert_warn(sdp, !(ret & LM_OUT_ASYNC));
 809
 810         state_change(gl, ret & LM_OUT_ST_MASK);
 811
 812         if (prev_state != LM_ST_UNLOCKED && !(ret & LM_OUT_CACHEABLE)) {
 813                 if (glops->go_inval)
 814                         glops->go_inval(gl, DIO_METADATA | DIO_DATA);
 815         } else if (gl->gl_state == LM_ST_DEFERRED) {
 816                 /* We might not want to do this here.
 817                    Look at moving to the inode glops. */
 818                 if (glops->go_inval)
 819                         glops->go_inval(gl, DIO_DATA);
 820         }
 821
 822         /*  Deal with each possible exit condition  */
 823
 824         if (!gh)
 825                 gl->gl_stamp = jiffies;
 826         else if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags))) {
 827                 spin_lock(&gl->gl_spin);
 828                 list_del_init(&gh->gh_list);
 829                 gh->gh_error = -EIO;
 830                 spin_unlock(&gl->gl_spin);
 831         } else if (test_bit(HIF_DEMOTE, &gh->gh_iflags)) {
 832                 spin_lock(&gl->gl_spin);
 833                 list_del_init(&gh->gh_list);
 834                 if (gl->gl_state == gh->gh_state ||
 835                     gl->gl_state == LM_ST_UNLOCKED) {
 836                         gh->gh_error = 0;
 837                 } else {
 838                         if (gfs2_assert_warn(sdp, gh->gh_flags &
 839                                         (LM_FLAG_TRY | LM_FLAG_TRY_1CB)) == -1)
 840                                 fs_warn(sdp, "ret = 0x%.8X\n", ret);
 841                         gh->gh_error = GLR_TRYFAILED;
 842                 }
 843                 spin_unlock(&gl->gl_spin);
 844
 845                 if (ret & LM_OUT_CANCELED)
 846                         handle_callback(gl, LM_ST_UNLOCKED);
 847
 848         } else if (ret & LM_OUT_CANCELED) {
 849                 spin_lock(&gl->gl_spin);
 850                 list_del_init(&gh->gh_list);
 851                 gh->gh_error = GLR_CANCELED;
 852                 spin_unlock(&gl->gl_spin);
 853
 854         } else if (relaxed_state_ok(gl->gl_state, gh->gh_state, gh->gh_flags)) {
 855                 spin_lock(&gl->gl_spin);
 856                 list_move_tail(&gh->gh_list, &gl->gl_holders);
 857                 gh->gh_error = 0;
 858                 set_bit(HIF_HOLDER, &gh->gh_iflags);
 859                 spin_unlock(&gl->gl_spin);
 860
 861                 set_bit(HIF_FIRST, &gh->gh_iflags);
 862
 863                 op_done = 0;
 864
 865         } else if (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)) {
 866                 spin_lock(&gl->gl_spin);
 867                 list_del_init(&gh->gh_list);
 868                 gh->gh_error = GLR_TRYFAILED;
 869                 spin_unlock(&gl->gl_spin);
 870
 871         } else {
 872                 if (gfs2_assert_withdraw(sdp, 0) == -1)
 873                         fs_err(sdp, "ret = 0x%.8X\n", ret);
 874         }
 875
 876         if (glops->go_xmote_bh)
 877                 glops->go_xmote_bh(gl);
 878
 879         if (op_done) {
 880                 spin_lock(&gl->gl_spin);
 881                 gl->gl_req_gh = NULL;
 882                 gl->gl_req_bh = NULL;
 883                 clear_bit(GLF_LOCK, &gl->gl_flags);
 884                 run_queue(gl);
 885                 spin_unlock(&gl->gl_spin);
 886         }
 887
 888         gfs2_glock_put(gl);
 889
 890         if (gh) {
 891                 if (test_bit(HIF_DEALLOC, &gh->gh_iflags))
 892                         gfs2_holder_put(gh);
 893                 else
 894                         complete(&gh->gh_wait);
 895         }
 896 }
 897
 898 /**
 899  * gfs2_glock_xmote_th - Call into the lock module to acquire or change a glock
 900  * @gl: The glock in question
 901  * @state: the requested state
 902  * @flags: modifier flags to the lock call
 903  *
 904  */
 905
 906 void gfs2_glock_xmote_th(struct gfs2_glock *gl, unsigned int state, int flags)
 907 {
 908         struct gfs2_sbd *sdp = gl->gl_sbd;
 909         const struct gfs2_glock_operations *glops = gl->gl_ops;
 910         int lck_flags = flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB |
 911                                  LM_FLAG_NOEXP | LM_FLAG_ANY |
 912                                  LM_FLAG_PRIORITY);
 913         unsigned int lck_ret;
 914
 915         gfs2_assert_warn(sdp, test_bit(GLF_LOCK, &gl->gl_flags));
 916         gfs2_assert_warn(sdp, queue_empty(gl, &gl->gl_holders));
 917         gfs2_assert_warn(sdp, state != LM_ST_UNLOCKED);
 918         gfs2_assert_warn(sdp, state != gl->gl_state);
 919
 920         if (gl->gl_state == LM_ST_EXCLUSIVE && glops->go_sync)
 921                 glops->go_sync(gl, DIO_METADATA | DIO_DATA | DIO_RELEASE);
 922
 923         gfs2_glock_hold(gl);
 924         gl->gl_req_bh = xmote_bh;
 925
 926         lck_ret = gfs2_lm_lock(sdp, gl->gl_lock, gl->gl_state, state, lck_flags);
 927
 928         if (gfs2_assert_withdraw(sdp, !(lck_ret & LM_OUT_ERROR)))
 929                 return;
 930
 931         if (lck_ret & LM_OUT_ASYNC)
 932                 gfs2_assert_warn(sdp, lck_ret == LM_OUT_ASYNC);
 933         else
 934                 xmote_bh(gl, lck_ret);
 935 }
 936
 937 /**
 938  * drop_bh - Called after a lock module unlock completes
 939  * @gl: the glock
 940  * @ret: the return status
 941  *
 942  * Doesn't wake up the process waiting on the struct gfs2_holder (if any)
 943  * Doesn't drop the reference on the glock the top half took out
 944  *
 945  */
 946
 947 static void drop_bh(struct gfs2_glock *gl, unsigned int ret)
 948 {
 949         struct gfs2_sbd *sdp = gl->gl_sbd;
 950         const struct gfs2_glock_operations *glops = gl->gl_ops;
 951         struct gfs2_holder *gh = gl->gl_req_gh;
 952
 953         clear_bit(GLF_PREFETCH, &gl->gl_flags);
 954
 955         gfs2_assert_warn(sdp, test_bit(GLF_LOCK, &gl->gl_flags));
 956         gfs2_assert_warn(sdp, queue_empty(gl, &gl->gl_holders));
 957         gfs2_assert_warn(sdp, !ret);
 958
 959         state_change(gl, LM_ST_UNLOCKED);
 960
 961         if (glops->go_inval)
 962                 glops->go_inval(gl, DIO_METADATA | DIO_DATA);
 963
 964         if (gh) {
 965                 spin_lock(&gl->gl_spin);
 966                 list_del_init(&gh->gh_list);
 967                 gh->gh_error = 0;
 968                 spin_unlock(&gl->gl_spin);
 969         }
 970
 971         if (glops->go_drop_bh)
 972                 glops->go_drop_bh(gl);
 973
 974         spin_lock(&gl->gl_spin);
 975         gl->gl_req_gh = NULL;
 976         gl->gl_req_bh = NULL;
 977         clear_bit(GLF_LOCK, &gl->gl_flags);
 978         run_queue(gl);
 979         spin_unlock(&gl->gl_spin);
 980
 981         gfs2_glock_put(gl);
 982
 983         if (gh) {
 984                 if (test_bit(HIF_DEALLOC, &gh->gh_iflags))
 985                         gfs2_holder_put(gh);
 986                 else
 987                         complete(&gh->gh_wait);
 988         }
 989 }
 990
 991 /**
 992  * gfs2_glock_drop_th - call into the lock module to unlock a lock
 993  * @gl: the glock
 994  *
 995  */
 996
 997 void gfs2_glock_drop_th(struct gfs2_glock *gl)
 998 {
 999         struct gfs2_sbd *sdp = gl->gl_sbd;
1000         const struct gfs2_glock_operations *glops = gl->gl_ops;
1001         unsigned int ret;
1002
1003         gfs2_assert_warn(sdp, test_bit(GLF_LOCK, &gl->gl_flags));
1004         gfs2_assert_warn(sdp, queue_empty(gl, &gl->gl_holders));
1005         gfs2_assert_warn(sdp, gl->gl_state != LM_ST_UNLOCKED);
1006
1007         if (gl->gl_state == LM_ST_EXCLUSIVE && glops->go_sync)
1008                 glops->go_sync(gl, DIO_METADATA | DIO_DATA | DIO_RELEASE);
1009
1010         gfs2_glock_hold(gl);
1011         gl->gl_req_bh = drop_bh;
1012
1013         ret = gfs2_lm_unlock(sdp, gl->gl_lock, gl->gl_state);
1014
1015         if (gfs2_assert_withdraw(sdp, !(ret & LM_OUT_ERROR)))
1016                 return;
1017
1018         if (!ret)
1019                 drop_bh(gl, ret);
1020         else
1021                 gfs2_assert_warn(sdp, ret == LM_OUT_ASYNC);
1022 }
1023
1024 /**
1025  * do_cancels - cancel requests for locks stuck waiting on an expire flag
1026  * @gh: the LM_FLAG_PRIORITY holder waiting to acquire the lock
1027  *
1028  * Don't cancel GL_NOCANCEL requests.
1029  */
1030
1031 static void do_cancels(struct gfs2_holder *gh)
1032 {
1033         struct gfs2_glock *gl = gh->gh_gl;
1034
1035         spin_lock(&gl->gl_spin);
1036
1037         while (gl->gl_req_gh != gh &&
1038                !test_bit(HIF_HOLDER, &gh->gh_iflags) &&
1039                !list_empty(&gh->gh_list)) {
1040                 if (gl->gl_req_bh && !(gl->gl_req_gh &&
1041                                      (gl->gl_req_gh->gh_flags & GL_NOCANCEL))) {
1042                         spin_unlock(&gl->gl_spin);
1043                         gfs2_lm_cancel(gl->gl_sbd, gl->gl_lock);
1044                         msleep(100);
1045                         spin_lock(&gl->gl_spin);
1046                 } else {
1047                         spin_unlock(&gl->gl_spin);
1048                         msleep(100);
1049                         spin_lock(&gl->gl_spin);
1050                 }
1051         }
1052
1053         spin_unlock(&gl->gl_spin);
1054 }
1055
1056 /**
1057  * glock_wait_internal - wait on a glock acquisition
1058  * @gh: the glock holder
1059  *
1060  * Returns: 0 on success
1061  */
1062
1063 static int glock_wait_internal(struct gfs2_holder *gh)
1064 {
1065         struct gfs2_glock *gl = gh->gh_gl;
1066         struct gfs2_sbd *sdp = gl->gl_sbd;
1067         const struct gfs2_glock_operations *glops = gl->gl_ops;
1068
1069         if (test_bit(HIF_ABORTED, &gh->gh_iflags))
1070                 return -EIO;
1071
1072         if (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)) {
1073                 spin_lock(&gl->gl_spin);
1074                 if (gl->gl_req_gh != gh &&
1075                     !test_bit(HIF_HOLDER, &gh->gh_iflags) &&
1076                     !list_empty(&gh->gh_list)) {
1077                         list_del_init(&gh->gh_list);
1078                         gh->gh_error = GLR_TRYFAILED;
1079                         run_queue(gl);
1080                         spin_unlock(&gl->gl_spin);
1081                         return gh->gh_error;
1082                 }
1083                 spin_unlock(&gl->gl_spin);
1084         }
1085
1086         if (gh->gh_flags & LM_FLAG_PRIORITY)
1087                 do_cancels(gh);
1088
1089         wait_for_completion(&gh->gh_wait);
1090
1091         if (gh->gh_error)
1092                 return gh->gh_error;
1093
1094         gfs2_assert_withdraw(sdp, test_bit(HIF_HOLDER, &gh->gh_iflags));
1095         gfs2_assert_withdraw(sdp, relaxed_state_ok(gl->gl_state, gh->gh_state,
1096                                                    gh->gh_flags));
1097
1098         if (test_bit(HIF_FIRST, &gh->gh_iflags)) {
1099                 gfs2_assert_warn(sdp, test_bit(GLF_LOCK, &gl->gl_flags));
1100
1101                 if (glops->go_lock) {
1102                         gh->gh_error = glops->go_lock(gh);
1103                         if (gh->gh_error) {
1104                                 spin_lock(&gl->gl_spin);
1105                                 list_del_init(&gh->gh_list);
1106                                 spin_unlock(&gl->gl_spin);
1107                         }
1108                 }
1109
1110                 spin_lock(&gl->gl_spin);
1111                 gl->gl_req_gh = NULL;
1112                 gl->gl_req_bh = NULL;
1113                 clear_bit(GLF_LOCK, &gl->gl_flags);
1114                 run_queue(gl);
1115                 spin_unlock(&gl->gl_spin);
1116         }
1117
1118         return gh->gh_error;
1119 }
1120
1121 static inline struct gfs2_holder *
1122 find_holder_by_owner(struct list_head *head, struct task_struct *owner)
1123 {
1124         struct gfs2_holder *gh;
1125
1126         list_for_each_entry(gh, head, gh_list) {
1127                 if (gh->gh_owner == owner)
1128                         return gh;
1129         }
1130
1131         return NULL;
1132 }
1133
1134 /**
1135  * add_to_queue - Add a holder to the wait queue (but look for recursion)
1136  * @gh: the holder structure to add
1137  *
1138  */
1139
1140 static void add_to_queue(struct gfs2_holder *gh)
1141 {
1142         struct gfs2_glock *gl = gh->gh_gl;
1143         struct gfs2_holder *existing;
1144
1145         BUG_ON(!gh->gh_owner);
1146
1147         existing = find_holder_by_owner(&gl->gl_holders, gh->gh_owner);
1148         if (existing) {
1149                 print_symbol(KERN_WARNING "original: %s\n", existing->gh_ip);
1150                 printk(KERN_INFO "pid : %d\n", existing->gh_owner->pid);
1151                 printk(KERN_INFO "lock type : %d lock state : %d\n",
1152                                 existing->gh_gl->gl_name.ln_type, existing->gh_gl->gl_state);
1153                 print_symbol(KERN_WARNING "new: %s\n", gh->gh_ip);
1154                 printk(KERN_INFO "pid : %d\n", gh->gh_owner->pid);
1155                 printk(KERN_INFO "lock type : %d lock state : %d\n",
1156                                 gl->gl_name.ln_type, gl->gl_state);
1157                 BUG();
1158         }
1159
1160         existing = find_holder_by_owner(&gl->gl_waiters3, gh->gh_owner);
1161         if (existing) {
1162                 print_symbol(KERN_WARNING "original: %s\n", existing->gh_ip);
1163                 print_symbol(KERN_WARNING "new: %s\n", gh->gh_ip);
1164                 BUG();
1165         }
1166
1167         if (gh->gh_flags & LM_FLAG_PRIORITY)
1168                 list_add(&gh->gh_list, &gl->gl_waiters3);
1169         else
1170                 list_add_tail(&gh->gh_list, &gl->gl_waiters3);
1171 }
1172
1173 /**
1174  * gfs2_glock_nq - enqueue a struct gfs2_holder onto a glock (acquire a glock)
1175  * @gh: the holder structure
1176  *
1177  * if (gh->gh_flags & GL_ASYNC), this never returns an error
1178  *
1179  * Returns: 0, GLR_TRYFAILED, or errno on failure
1180  */
1181
1182 int gfs2_glock_nq(struct gfs2_holder *gh)
1183 {
1184         struct gfs2_glock *gl = gh->gh_gl;
1185         struct gfs2_sbd *sdp = gl->gl_sbd;
1186         int error = 0;
1187
1188 restart:
1189         if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags))) {
1190                 set_bit(HIF_ABORTED, &gh->gh_iflags);
1191                 return -EIO;
1192         }
1193
1194         set_bit(HIF_PROMOTE, &gh->gh_iflags);
1195
1196         spin_lock(&gl->gl_spin);
1197         add_to_queue(gh);
1198         run_queue(gl);
1199         spin_unlock(&gl->gl_spin);
1200
1201         if (!(gh->gh_flags & GL_ASYNC)) {
1202                 error = glock_wait_internal(gh);
1203                 if (error == GLR_CANCELED) {
1204                         msleep(100);
1205                         goto restart;
1206                 }
1207         }
1208
1209         clear_bit(GLF_PREFETCH, &gl->gl_flags);
1210
1211         if (error == GLR_TRYFAILED && (gh->gh_flags & GL_DUMP))
1212                 dump_glock(gl);
1213
1214         return error;
1215 }
1216
1217 /**
1218  * gfs2_glock_poll - poll to see if an async request has been completed
1219  * @gh: the holder
1220  *
1221  * Returns: 1 if the request is ready to be gfs2_glock_wait()ed on
1222  */
1223
1224 int gfs2_glock_poll(struct gfs2_holder *gh)
1225 {
1226         struct gfs2_glock *gl = gh->gh_gl;
1227         int ready = 0;
1228
1229         spin_lock(&gl->gl_spin);
1230
1231         if (test_bit(HIF_HOLDER, &gh->gh_iflags))
1232                 ready = 1;
1233         else if (list_empty(&gh->gh_list)) {
1234                 if (gh->gh_error == GLR_CANCELED) {
1235                         spin_unlock(&gl->gl_spin);
1236                         msleep(100);
1237                         if (gfs2_glock_nq(gh))
1238                                 return 1;
1239                         return 0;
1240                 } else
1241                         ready = 1;
1242         }
1243
1244         spin_unlock(&gl->gl_spin);
1245
1246         return ready;
1247 }
1248
1249 /**
1250  * gfs2_glock_wait - wait for a lock acquisition that ended in a GLR_ASYNC
1251  * @gh: the holder structure
1252  *
1253  * Returns: 0, GLR_TRYFAILED, or errno on failure
1254  */
1255
1256 int gfs2_glock_wait(struct gfs2_holder *gh)
1257 {
1258         int error;
1259
1260         error = glock_wait_internal(gh);
1261         if (error == GLR_CANCELED) {
1262                 msleep(100);
1263                 gh->gh_flags &= ~GL_ASYNC;
1264                 error = gfs2_glock_nq(gh);
1265         }
1266
1267         return error;
1268 }
1269
1270 /**
1271  * gfs2_glock_dq - dequeue a struct gfs2_holder from a glock (release a glock)
1272  * @gh: the glock holder
1273  *
1274  */
1275
1276 void gfs2_glock_dq(struct gfs2_holder *gh)
1277 {
1278         struct gfs2_glock *gl = gh->gh_gl;
1279         const struct gfs2_glock_operations *glops = gl->gl_ops;
1280
1281         if (gh->gh_flags & GL_NOCACHE)
1282                 handle_callback(gl, LM_ST_UNLOCKED);
1283
1284         gfs2_glmutex_lock(gl);
1285
1286         spin_lock(&gl->gl_spin);
1287         list_del_init(&gh->gh_list);
1288
1289         if (list_empty(&gl->gl_holders)) {
1290                 spin_unlock(&gl->gl_spin);
1291
1292                 if (glops->go_unlock)
1293                         glops->go_unlock(gh);
1294
1295                 gl->gl_stamp = jiffies;
1296
1297                 spin_lock(&gl->gl_spin);
1298         }
1299
1300         clear_bit(GLF_LOCK, &gl->gl_flags);
1301         run_queue(gl);
1302         spin_unlock(&gl->gl_spin);
1303 }
1304
1305 /**
1306  * gfs2_glock_prefetch - Try to prefetch a glock
1307  * @gl: the glock
1308  * @state: the state to prefetch in
1309  * @flags: flags passed to go_xmote_th()
1310  *
1311  */
1312
1313 static void gfs2_glock_prefetch(struct gfs2_glock *gl, unsigned int state,
1314                                 int flags)
1315 {
1316         const struct gfs2_glock_operations *glops = gl->gl_ops;
1317
1318         spin_lock(&gl->gl_spin);
1319
1320         if (test_bit(GLF_LOCK, &gl->gl_flags) || !list_empty(&gl->gl_holders) ||
1321             !list_empty(&gl->gl_waiters1) || !list_empty(&gl->gl_waiters2) ||
1322             !list_empty(&gl->gl_waiters3) ||
1323             relaxed_state_ok(gl->gl_state, state, flags)) {
1324                 spin_unlock(&gl->gl_spin);
1325                 return;
1326         }
1327
1328         set_bit(GLF_PREFETCH, &gl->gl_flags);
1329         set_bit(GLF_LOCK, &gl->gl_flags);
1330         spin_unlock(&gl->gl_spin);
1331
1332         glops->go_xmote_th(gl, state, flags);
1333 }
1334
1335 static void greedy_work(void *data)
1336 {
1337         struct greedy *gr = data;
1338         struct gfs2_holder *gh = &gr->gr_gh;
1339         struct gfs2_glock *gl = gh->gh_gl;
1340         const struct gfs2_glock_operations *glops = gl->gl_ops;
1341
1342         clear_bit(GLF_SKIP_WAITERS2, &gl->gl_flags);
1343
1344         if (glops->go_greedy)
1345                 glops->go_greedy(gl);
1346
1347         spin_lock(&gl->gl_spin);
1348
1349         if (list_empty(&gl->gl_waiters2)) {
1350                 clear_bit(GLF_GREEDY, &gl->gl_flags);
1351                 spin_unlock(&gl->gl_spin);
1352                 gfs2_holder_uninit(gh);
1353                 kfree(gr);
1354         } else {
1355                 gfs2_glock_hold(gl);
1356                 list_add_tail(&gh->gh_list, &gl->gl_waiters2);
1357                 run_queue(gl);
1358                 spin_unlock(&gl->gl_spin);
1359                 gfs2_glock_put(gl);
1360         }
1361 }
1362
1363 /**
1364  * gfs2_glock_be_greedy -
1365  * @gl:
1366  * @time:
1367  *
1368  * Returns: 0 if go_greedy will be called, 1 otherwise
1369  */
1370
1371 int gfs2_glock_be_greedy(struct gfs2_glock *gl, unsigned int time)
1372 {
1373         struct greedy *gr;
1374         struct gfs2_holder *gh;
1375
1376         if (!time || gl->gl_sbd->sd_args.ar_localcaching ||
1377             test_and_set_bit(GLF_GREEDY, &gl->gl_flags))
1378                 return 1;
1379
1380         gr = kmalloc(sizeof(struct greedy), GFP_KERNEL);
1381         if (!gr) {
1382                 clear_bit(GLF_GREEDY, &gl->gl_flags);
1383                 return 1;
1384         }
1385         gh = &gr->gr_gh;
1386
1387         gfs2_holder_init(gl, 0, 0, gh);
1388         set_bit(HIF_GREEDY, &gh->gh_iflags);
1389         INIT_WORK(&gr->gr_work, greedy_work, gr);
1390
1391         set_bit(GLF_SKIP_WAITERS2, &gl->gl_flags);
1392         schedule_delayed_work(&gr->gr_work, time);
1393
1394         return 0;
1395 }
1396
1397 /**
1398  * gfs2_glock_dq_uninit - dequeue a holder from a glock and initialize it
1399  * @gh: the holder structure
1400  *
1401  */
1402
1403 void gfs2_glock_dq_uninit(struct gfs2_holder *gh)
1404 {
1405         gfs2_glock_dq(gh);
1406         gfs2_holder_uninit(gh);
1407 }
1408
1409 /**
1410  * gfs2_glock_nq_num - acquire a glock based on lock number
1411  * @sdp: the filesystem
1412  * @number: the lock number
1413  * @glops: the glock operations for the type of glock
1414  * @state: the state to acquire the glock in
1415  * @flags: modifier flags for the aquisition
1416  * @gh: the struct gfs2_holder
1417  *
1418  * Returns: errno
1419  */
1420
1421 int gfs2_glock_nq_num(struct gfs2_sbd *sdp, u64 number,
1422                       const struct gfs2_glock_operations *glops,
1423                       unsigned int state, int flags, struct gfs2_holder *gh)
1424 {
1425         struct gfs2_glock *gl;
1426         int error;
1427
1428         error = gfs2_glock_get(sdp, number, glops, CREATE, &gl);
1429         if (!error) {
1430                 error = gfs2_glock_nq_init(gl, state, flags, gh);
1431                 gfs2_glock_put(gl);
1432         }
1433
1434         return error;
1435 }
1436
1437 /**
1438  * glock_compare - Compare two struct gfs2_glock structures for sorting
1439  * @arg_a: the first structure
1440  * @arg_b: the second structure
1441  *
1442  */
1443
1444 static int glock_compare(const void *arg_a, const void *arg_b)
1445 {
1446         struct gfs2_holder *gh_a = *(struct gfs2_holder **)arg_a;
1447         struct gfs2_holder *gh_b = *(struct gfs2_holder **)arg_b;
1448         struct lm_lockname *a = &gh_a->gh_gl->gl_name;
1449         struct lm_lockname *b = &gh_b->gh_gl->gl_name;
1450         int ret = 0;
1451
1452         if (a->ln_number > b->ln_number)
1453                 ret = 1;
1454         else if (a->ln_number < b->ln_number)
1455                 ret = -1;
1456         else {
1457                 if (gh_a->gh_state == LM_ST_SHARED &&
1458                     gh_b->gh_state == LM_ST_EXCLUSIVE)
1459                         ret = 1;
1460                 else if (!(gh_a->gh_flags & GL_LOCAL_EXCL) &&
1461                          (gh_b->gh_flags & GL_LOCAL_EXCL))
1462                         ret = 1;
1463         }
1464
1465         return ret;
1466 }
1467
1468 /**
1469  * nq_m_sync - synchonously acquire more than one glock in deadlock free order
1470  * @num_gh: the number of structures
1471  * @ghs: an array of struct gfs2_holder structures
1472  *
1473  * Returns: 0 on success (all glocks acquired),
1474  *          errno on failure (no glocks acquired)
1475  */
1476
1477 static int nq_m_sync(unsigned int num_gh, struct gfs2_holder *ghs,
1478                      struct gfs2_holder **p)
1479 {
1480         unsigned int x;
1481         int error = 0;
1482
1483         for (x = 0; x < num_gh; x++)
1484                 p[x] = &ghs[x];
1485
1486         sort(p, num_gh, sizeof(struct gfs2_holder *), glock_compare, NULL);
1487
1488         for (x = 0; x < num_gh; x++) {
1489                 p[x]->gh_flags &= ~(LM_FLAG_TRY | GL_ASYNC);
1490
1491                 error = gfs2_glock_nq(p[x]);
1492                 if (error) {
1493                         while (x--)
1494                                 gfs2_glock_dq(p[x]);
1495                         break;
1496                 }
1497         }
1498
1499         return error;
1500 }
1501
1502 /**
1503  * gfs2_glock_nq_m - acquire multiple glocks
1504  * @num_gh: the number of structures
1505  * @ghs: an array of struct gfs2_holder structures
1506  *
1507  * Figure out how big an impact this function has.  Either:
1508  * 1) Replace this code with code that calls gfs2_glock_prefetch()
1509  * 2) Forget async stuff and just call nq_m_sync()
1510  * 3) Leave it like it is
1511  *
1512  * Returns: 0 on success (all glocks acquired),
1513  *          errno on failure (no glocks acquired)
1514  */
1515
1516 int gfs2_glock_nq_m(unsigned int num_gh, struct gfs2_holder *ghs)
1517 {
1518         int *e;
1519         unsigned int x;
1520         int borked = 0, serious = 0;
1521         int error = 0;
1522
1523         if (!num_gh)
1524                 return 0;
1525
1526         if (num_gh == 1) {
1527                 ghs->gh_flags &= ~(LM_FLAG_TRY | GL_ASYNC);
1528                 return gfs2_glock_nq(ghs);
1529         }
1530
1531         e = kcalloc(num_gh, sizeof(struct gfs2_holder *), GFP_KERNEL);
1532         if (!e)
1533                 return -ENOMEM;
1534
1535         for (x = 0; x < num_gh; x++) {
1536                 ghs[x].gh_flags |= LM_FLAG_TRY | GL_ASYNC;
1537                 error = gfs2_glock_nq(&ghs[x]);
1538                 if (error) {
1539                         borked = 1;
1540                         serious = error;
1541                         num_gh = x;
1542                         break;
1543                 }
1544         }
1545
1546         for (x = 0; x < num_gh; x++) {
1547                 error = e[x] = glock_wait_internal(&ghs[x]);
1548                 if (error) {
1549                         borked = 1;
1550                         if (error != GLR_TRYFAILED && error != GLR_CANCELED)
1551                                 serious = error;
1552                 }
1553         }
1554
1555         if (!borked) {
1556                 kfree(e);
1557                 return 0;
1558         }
1559
1560         for (x = 0; x < num_gh; x++)
1561                 if (!e[x])
1562                         gfs2_glock_dq(&ghs[x]);
1563
1564         if (serious)
1565                 error = serious;
1566         else {
1567                 for (x = 0; x < num_gh; x++)
1568                         gfs2_holder_reinit(ghs[x].gh_state, ghs[x].gh_flags,
1569                                           &ghs[x]);
1570                 error = nq_m_sync(num_gh, ghs, (struct gfs2_holder **)e);
1571         }
1572
1573         kfree(e);
1574
1575         return error;
1576 }
1577
1578 /**
1579  * gfs2_glock_dq_m - release multiple glocks
1580  * @num_gh: the number of structures
1581  * @ghs: an array of struct gfs2_holder structures
1582  *
1583  */
1584
1585 void gfs2_glock_dq_m(unsigned int num_gh, struct gfs2_holder *ghs)
1586 {
1587         unsigned int x;
1588
1589         for (x = 0; x < num_gh; x++)
1590                 gfs2_glock_dq(&ghs[x]);
1591 }
1592
1593 /**
1594  * gfs2_glock_dq_uninit_m - release multiple glocks
1595  * @num_gh: the number of structures
1596  * @ghs: an array of struct gfs2_holder structures
1597  *
1598  */
1599
1600 void gfs2_glock_dq_uninit_m(unsigned int num_gh, struct gfs2_holder *ghs)
1601 {
1602         unsigned int x;
1603
1604         for (x = 0; x < num_gh; x++)
1605                 gfs2_glock_dq_uninit(&ghs[x]);
1606 }
1607
1608 /**
1609  * gfs2_glock_prefetch_num - prefetch a glock based on lock number
1610  * @sdp: the filesystem
1611  * @number: the lock number
1612  * @glops: the glock operations for the type of glock
1613  * @state: the state to acquire the glock in
1614  * @flags: modifier flags for the aquisition
1615  *
1616  * Returns: errno
1617  */
1618
1619 void gfs2_glock_prefetch_num(struct gfs2_sbd *sdp, u64 number,
1620                              const struct gfs2_glock_operations *glops,
1621                              unsigned int state, int flags)
1622 {
1623         struct gfs2_glock *gl;
1624         int error;
1625
1626         if (atomic_read(&sdp->sd_reclaim_count) <
1627             gfs2_tune_get(sdp, gt_reclaim_limit)) {
1628                 error = gfs2_glock_get(sdp, number, glops, CREATE, &gl);
1629                 if (!error) {
1630                         gfs2_glock_prefetch(gl, state, flags);
1631                         gfs2_glock_put(gl);
1632                 }
1633         }
1634 }
1635
1636 /**
1637  * gfs2_lvb_hold - attach a LVB from a glock
1638  * @gl: The glock in question
1639  *
1640  */
1641
1642 int gfs2_lvb_hold(struct gfs2_glock *gl)
1643 {
1644         int error;
1645
1646         gfs2_glmutex_lock(gl);
1647
1648         if (!atomic_read(&gl->gl_lvb_count)) {
1649                 error = gfs2_lm_hold_lvb(gl->gl_sbd, gl->gl_lock, &gl->gl_lvb);
1650                 if (error) {
1651                         gfs2_glmutex_unlock(gl);
1652                         return error;
1653                 }
1654                 gfs2_glock_hold(gl);
1655         }
1656         atomic_inc(&gl->gl_lvb_count);
1657
1658         gfs2_glmutex_unlock(gl);
1659
1660         return 0;
1661 }
1662
1663 /**
1664  * gfs2_lvb_unhold - detach a LVB from a glock
1665  * @gl: The glock in question
1666  *
1667  */
1668
1669 void gfs2_lvb_unhold(struct gfs2_glock *gl)
1670 {
1671         gfs2_glock_hold(gl);
1672         gfs2_glmutex_lock(gl);
1673
1674         gfs2_assert(gl->gl_sbd, atomic_read(&gl->gl_lvb_count) > 0);
1675         if (atomic_dec_and_test(&gl->gl_lvb_count)) {
1676                 gfs2_lm_unhold_lvb(gl->gl_sbd, gl->gl_lock, gl->gl_lvb);
1677                 gl->gl_lvb = NULL;
1678                 gfs2_glock_put(gl);
1679         }
1680
1681         gfs2_glmutex_unlock(gl);
1682         gfs2_glock_put(gl);
1683 }
1684
1685 static void blocking_cb(struct gfs2_sbd *sdp, struct lm_lockname *name,
1686                         unsigned int state)
1687 {
1688         struct gfs2_glock *gl;
1689
1690         gl = gfs2_glock_find(sdp, name);
1691         if (!gl)
1692                 return;
1693
1694         if (gl->gl_ops->go_callback)
1695                 gl->gl_ops->go_callback(gl, state);
1696         handle_callback(gl, state);
1697
1698         spin_lock(&gl->gl_spin);
1699         run_queue(gl);
1700         spin_unlock(&gl->gl_spin);
1701
1702         gfs2_glock_put(gl);
1703 }
1704
1705 /**
1706  * gfs2_glock_cb - Callback used by locking module
1707  * @sdp: Pointer to the superblock
1708  * @type: Type of callback
1709  * @data: Type dependent data pointer
1710  *
1711  * Called by the locking module when it wants to tell us something.
1712  * Either we need to drop a lock, one of our ASYNC requests completed, or
1713  * a journal from another client needs to be recovered.
1714  */
1715
1716 void gfs2_glock_cb(void *cb_data, unsigned int type, void *data)
1717 {
1718         struct gfs2_sbd *sdp = cb_data;
1719
1720         switch (type) {
1721         case LM_CB_NEED_E:
1722                 blocking_cb(sdp, data, LM_ST_UNLOCKED);
1723                 return;
1724
1725         case LM_CB_NEED_D:
1726                 blocking_cb(sdp, data, LM_ST_DEFERRED);
1727                 return;
1728
1729         case LM_CB_NEED_S:
1730                 blocking_cb(sdp, data, LM_ST_SHARED);
1731                 return;
1732
1733         case LM_CB_ASYNC: {
1734                 struct lm_async_cb *async = data;
1735                 struct gfs2_glock *gl;
1736
1737                 gl = gfs2_glock_find(sdp, &async->lc_name);
1738                 if (gfs2_assert_warn(sdp, gl))
1739                         return;
1740                 if (!gfs2_assert_warn(sdp, gl->gl_req_bh))
1741                         gl->gl_req_bh(gl, async->lc_ret);
1742                 gfs2_glock_put(gl);
1743                 return;
1744         }
1745
1746         case LM_CB_NEED_RECOVERY:
1747                 gfs2_jdesc_make_dirty(sdp, *(unsigned int *)data);
1748                 if (sdp->sd_recoverd_process)
1749                         wake_up_process(sdp->sd_recoverd_process);
1750                 return;
1751
1752         case LM_CB_DROPLOCKS:
1753                 gfs2_gl_hash_clear(sdp, NO_WAIT);
1754                 gfs2_quota_scan(sdp);
1755                 return;
1756
1757         default:
1758                 gfs2_assert_warn(sdp, 0);
1759                 return;
1760         }
1761 }
1762
1763 /**
1764  * gfs2_iopen_go_callback - Try to kick the inode/vnode associated with an
1765  *                          iopen glock from memory
1766  * @io_gl: the iopen glock
1767  * @state: the state into which the glock should be put
1768  *
1769  */
1770
1771 void gfs2_iopen_go_callback(struct gfs2_glock *io_gl, unsigned int state)
1772 {
1773
1774         if (state != LM_ST_UNLOCKED)
1775                 return;
1776         /* FIXME: remove this? */
1777 }
1778
1779 /**
1780  * demote_ok - Check to see if it's ok to unlock a glock
1781  * @gl: the glock
1782  *
1783  * Returns: 1 if it's ok
1784  */
1785
1786 static int demote_ok(struct gfs2_glock *gl)
1787 {
1788         struct gfs2_sbd *sdp = gl->gl_sbd;
1789         const struct gfs2_glock_operations *glops = gl->gl_ops;
1790         int demote = 1;
1791
1792         if (test_bit(GLF_STICKY, &gl->gl_flags))
1793                 demote = 0;
1794         else if (test_bit(GLF_PREFETCH, &gl->gl_flags))
1795                 demote = time_after_eq(jiffies, gl->gl_stamp +
1796                                     gfs2_tune_get(sdp, gt_prefetch_secs) * HZ);
1797         else if (glops->go_demote_ok)
1798                 demote = glops->go_demote_ok(gl);
1799
1800         return demote;
1801 }
1802
1803 /**
1804  * gfs2_glock_schedule_for_reclaim - Add a glock to the reclaim list
1805  * @gl: the glock
1806  *
1807  */
1808
1809 void gfs2_glock_schedule_for_reclaim(struct gfs2_glock *gl)
1810 {
1811         struct gfs2_sbd *sdp = gl->gl_sbd;
1812
1813         spin_lock(&sdp->sd_reclaim_lock);
1814         if (list_empty(&gl->gl_reclaim)) {
1815                 gfs2_glock_hold(gl);
1816                 list_add(&gl->gl_reclaim, &sdp->sd_reclaim_list);
1817                 atomic_inc(&sdp->sd_reclaim_count);
1818         }
1819         spin_unlock(&sdp->sd_reclaim_lock);
1820
1821         wake_up(&sdp->sd_reclaim_wq);
1822 }
1823
1824 /**
1825  * gfs2_reclaim_glock - process the next glock on the filesystem's reclaim list
1826  * @sdp: the filesystem
1827  *
1828  * Called from gfs2_glockd() glock reclaim daemon, or when promoting a
1829  * different glock and we notice that there are a lot of glocks in the
1830  * reclaim list.
1831  *
1832  */
1833
1834 void gfs2_reclaim_glock(struct gfs2_sbd *sdp)
1835 {
1836         struct gfs2_glock *gl;
1837
1838         spin_lock(&sdp->sd_reclaim_lock);
1839         if (list_empty(&sdp->sd_reclaim_list)) {
1840                 spin_unlock(&sdp->sd_reclaim_lock);
1841                 return;
1842         }
1843         gl = list_entry(sdp->sd_reclaim_list.next,
1844                         struct gfs2_glock, gl_reclaim);
1845         list_del_init(&gl->gl_reclaim);
1846         spin_unlock(&sdp->sd_reclaim_lock);
1847
1848         atomic_dec(&sdp->sd_reclaim_count);
1849         atomic_inc(&sdp->sd_reclaimed);
1850
1851         if (gfs2_glmutex_trylock(gl)) {
1852                 if (queue_empty(gl, &gl->gl_holders) &&
1853                     gl->gl_state != LM_ST_UNLOCKED && demote_ok(gl))
1854                         handle_callback(gl, LM_ST_UNLOCKED);
1855                 gfs2_glmutex_unlock(gl);
1856         }
1857
1858         gfs2_glock_put(gl);
1859 }
1860
1861 /**
1862  * examine_bucket - Call a function for glock in a hash bucket
1863  * @examiner: the function
1864  * @sdp: the filesystem
1865  * @bucket: the bucket
1866  *
1867  * Returns: 1 if the bucket has entries
1868  */
1869
1870 static int examine_bucket(glock_examiner examiner, struct gfs2_sbd *sdp,
1871                           unsigned int hash)
1872 {
1873         struct glock_plug plug;
1874         struct list_head *tmp;
1875         struct gfs2_glock *gl;
1876         int entries;
1877
1878         /* Add "plug" to end of bucket list, work back up list from there */
1879         memset(&plug.gl_flags, 0, sizeof(unsigned long));
1880         set_bit(GLF_PLUG, &plug.gl_flags);
1881
1882         write_lock(&gl_hash_locks[hash]);
1883         list_add(&plug.gl_list, &gl_hash_table[hash].hb_list);
1884         write_unlock(&gl_hash_locks[hash]);
1885
1886         for (;;) {
1887                 write_lock(&gl_hash_locks[hash]);
1888
1889                 for (;;) {
1890                         tmp = plug.gl_list.next;
1891
1892                         if (tmp == &gl_hash_table[hash].hb_list) {
1893                                 list_del(&plug.gl_list);
1894                                 entries = !list_empty(&gl_hash_table[hash].hb_list);
1895                                 write_unlock(&gl_hash_locks[hash]);
1896                                 return entries;
1897                         }
1898                         gl = list_entry(tmp, struct gfs2_glock, gl_list);
1899
1900                         /* Move plug up list */
1901                         list_move(&plug.gl_list, &gl->gl_list);
1902
1903                         if (test_bit(GLF_PLUG, &gl->gl_flags))
1904                                 continue;
1905                         if (gl->gl_sbd != sdp)
1906                                 continue;
1907
1908                         /* examiner() must glock_put() */
1909                         gfs2_glock_hold(gl);
1910
1911                         break;
1912                 }
1913
1914                 write_unlock(&gl_hash_locks[hash]);
1915
1916                 examiner(gl);
1917         }
1918 }
1919
1920 /**
1921  * scan_glock - look at a glock and see if we can reclaim it
1922  * @gl: the glock to look at
1923  *
1924  */
1925
1926 static void scan_glock(struct gfs2_glock *gl)
1927 {
1928         if (gl->gl_ops == &gfs2_inode_glops)
1929                 goto out;
1930
1931         if (gfs2_glmutex_trylock(gl)) {
1932                 if (queue_empty(gl, &gl->gl_holders) &&
1933                     gl->gl_state != LM_ST_UNLOCKED &&
1934                     demote_ok(gl))
1935                         goto out_schedule;
1936                 gfs2_glmutex_unlock(gl);
1937         }
1938 out:
1939         gfs2_glock_put(gl);
1940         return;
1941
1942 out_schedule:
1943         gfs2_glmutex_unlock(gl);
1944         gfs2_glock_schedule_for_reclaim(gl);
1945         gfs2_glock_put(gl);
1946 }
1947
1948 /**
1949  * gfs2_scand_internal - Look for glocks and inodes to toss from memory
1950  * @sdp: the filesystem
1951  *
1952  */
1953
1954 void gfs2_scand_internal(struct gfs2_sbd *sdp)
1955 {
1956         unsigned int x;
1957
1958         for (x = 0; x < GFS2_GL_HASH_SIZE; x++) {
1959                 examine_bucket(scan_glock, sdp, x);
1960                 cond_resched();
1961         }
1962 }
1963
1964 /**
1965  * clear_glock - look at a glock and see if we can free it from glock cache
1966  * @gl: the glock to look at
1967  *
1968  */
1969
1970 static void clear_glock(struct gfs2_glock *gl)
1971 {
1972         struct gfs2_sbd *sdp = gl->gl_sbd;
1973         int released;
1974
1975         spin_lock(&sdp->sd_reclaim_lock);
1976         if (!list_empty(&gl->gl_reclaim)) {
1977                 list_del_init(&gl->gl_reclaim);
1978                 atomic_dec(&sdp->sd_reclaim_count);
1979                 spin_unlock(&sdp->sd_reclaim_lock);
1980                 released = gfs2_glock_put(gl);
1981                 gfs2_assert(sdp, !released);
1982         } else {
1983                 spin_unlock(&sdp->sd_reclaim_lock);
1984         }
1985
1986         if (gfs2_glmutex_trylock(gl)) {
1987                 if (queue_empty(gl, &gl->gl_holders) &&
1988                     gl->gl_state != LM_ST_UNLOCKED)
1989                         handle_callback(gl, LM_ST_UNLOCKED);
1990
1991                 gfs2_glmutex_unlock(gl);
1992         }
1993
1994         gfs2_glock_put(gl);
1995 }
1996
1997 /**
1998  * gfs2_gl_hash_clear - Empty out the glock hash table
1999  * @sdp: the filesystem
2000  * @wait: wait until it's all gone
2001  *
2002  * Called when unmounting the filesystem, or when inter-node lock manager
2003  * requests DROPLOCKS because it is running out of capacity.
2004  */
2005
2006 void gfs2_gl_hash_clear(struct gfs2_sbd *sdp, int wait)
2007 {
2008         unsigned long t;
2009         unsigned int x;
2010         int cont;
2011
2012         t = jiffies;
2013
2014         for (;;) {
2015                 cont = 0;
2016
2017                 for (x = 0; x < GFS2_GL_HASH_SIZE; x++)
2018                         if (examine_bucket(clear_glock, sdp, x))
2019                                 cont = 1;
2020
2021                 if (!wait || !cont)
2022                         break;
2023
2024                 if (time_after_eq(jiffies,
2025                                   t + gfs2_tune_get(sdp, gt_stall_secs) * HZ)) {
2026                         fs_warn(sdp, "Unmount seems to be stalled. "
2027                                      "Dumping lock state...\n");
2028                         gfs2_dump_lockstate(sdp);
2029                         t = jiffies;
2030                 }
2031
2032                 invalidate_inodes(sdp->sd_vfs);
2033                 msleep(10);
2034         }
2035 }
2036
2037 /*
2038  *  Diagnostic routines to help debug distributed deadlock
2039  */
2040
2041 /**
2042  * dump_holder - print information about a glock holder
2043  * @str: a string naming the type of holder
2044  * @gh: the glock holder
2045  *
2046  * Returns: 0 on success, -ENOBUFS when we run out of space
2047  */
2048
2049 static int dump_holder(char *str, struct gfs2_holder *gh)
2050 {
2051         unsigned int x;
2052         int error = -ENOBUFS;
2053
2054         printk(KERN_INFO "  %s\n", str);
2055         printk(KERN_INFO "    owner = %ld\n",
2056                    (gh->gh_owner) ? (long)gh->gh_owner->pid : -1);
2057         printk(KERN_INFO "    gh_state = %u\n", gh->gh_state);
2058         printk(KERN_INFO "    gh_flags =");
2059         for (x = 0; x < 32; x++)
2060                 if (gh->gh_flags & (1 << x))
2061                         printk(" %u", x);
2062         printk(" \n");
2063         printk(KERN_INFO "    error = %d\n", gh->gh_error);
2064         printk(KERN_INFO "    gh_iflags =");
2065         for (x = 0; x < 32; x++)
2066                 if (test_bit(x, &gh->gh_iflags))
2067                         printk(" %u", x);
2068         printk(" \n");
2069         print_symbol(KERN_INFO "    initialized at: %s\n", gh->gh_ip);
2070
2071         error = 0;
2072
2073         return error;
2074 }
2075
2076 /**
2077  * dump_inode - print information about an inode
2078  * @ip: the inode
2079  *
2080  * Returns: 0 on success, -ENOBUFS when we run out of space
2081  */
2082
2083 static int dump_inode(struct gfs2_inode *ip)
2084 {
2085         unsigned int x;
2086         int error = -ENOBUFS;
2087
2088         printk(KERN_INFO "  Inode:\n");
2089         printk(KERN_INFO "    num = %llu %llu\n",
2090                     (unsigned long long)ip->i_num.no_formal_ino,
2091                     (unsigned long long)ip->i_num.no_addr);
2092         printk(KERN_INFO "    type = %u\n", IF2DT(ip->i_di.di_mode));
2093         printk(KERN_INFO "    i_flags =");
2094         for (x = 0; x < 32; x++)
2095                 if (test_bit(x, &ip->i_flags))
2096                         printk(" %u", x);
2097         printk(" \n");
2098
2099         error = 0;
2100
2101         return error;
2102 }
2103
2104 /**
2105  * dump_glock - print information about a glock
2106  * @gl: the glock
2107  * @count: where we are in the buffer
2108  *
2109  * Returns: 0 on success, -ENOBUFS when we run out of space
2110  */
2111
2112 static int dump_glock(struct gfs2_glock *gl)
2113 {
2114         struct gfs2_holder *gh;
2115         unsigned int x;
2116         int error = -ENOBUFS;
2117
2118         spin_lock(&gl->gl_spin);
2119
2120         printk(KERN_INFO "Glock 0x%p (%u, %llu)\n", gl, gl->gl_name.ln_type,
2121                (unsigned long long)gl->gl_name.ln_number);
2122         printk(KERN_INFO "  gl_flags =");
2123         for (x = 0; x < 32; x++) {
2124                 if (test_bit(x, &gl->gl_flags))
2125                         printk(" %u", x);
2126         }
2127         printk(" \n");
2128         printk(KERN_INFO "  gl_ref = %d\n", atomic_read(&gl->gl_ref.refcount));
2129         printk(KERN_INFO "  gl_state = %u\n", gl->gl_state);
2130         printk(KERN_INFO "  gl_owner = %s\n", gl->gl_owner->comm);
2131         print_symbol(KERN_INFO "  gl_ip = %s\n", gl->gl_ip);
2132         printk(KERN_INFO "  req_gh = %s\n", (gl->gl_req_gh) ? "yes" : "no");
2133         printk(KERN_INFO "  req_bh = %s\n", (gl->gl_req_bh) ? "yes" : "no");
2134         printk(KERN_INFO "  lvb_count = %d\n", atomic_read(&gl->gl_lvb_count));
2135         printk(KERN_INFO "  object = %s\n", (gl->gl_object) ? "yes" : "no");
2136         printk(KERN_INFO "  le = %s\n",
2137                    (list_empty(&gl->gl_le.le_list)) ? "no" : "yes");
2138         printk(KERN_INFO "  reclaim = %s\n",
2139                     (list_empty(&gl->gl_reclaim)) ? "no" : "yes");
2140         if (gl->gl_aspace)
2141                 printk(KERN_INFO "  aspace = 0x%p nrpages = %lu\n", gl->gl_aspace,
2142                        gl->gl_aspace->i_mapping->nrpages);
2143         else
2144                 printk(KERN_INFO "  aspace = no\n");
2145         printk(KERN_INFO "  ail = %d\n", atomic_read(&gl->gl_ail_count));
2146         if (gl->gl_req_gh) {
2147                 error = dump_holder("Request", gl->gl_req_gh);
2148                 if (error)
2149                         goto out;
2150         }
2151         list_for_each_entry(gh, &gl->gl_holders, gh_list) {
2152                 error = dump_holder("Holder", gh);
2153                 if (error)
2154                         goto out;
2155         }
2156         list_for_each_entry(gh, &gl->gl_waiters1, gh_list) {
2157                 error = dump_holder("Waiter1", gh);
2158                 if (error)
2159                         goto out;
2160         }
2161         list_for_each_entry(gh, &gl->gl_waiters2, gh_list) {
2162                 error = dump_holder("Waiter2", gh);
2163                 if (error)
2164                         goto out;
2165         }
2166         list_for_each_entry(gh, &gl->gl_waiters3, gh_list) {
2167                 error = dump_holder("Waiter3", gh);
2168                 if (error)
2169                         goto out;
2170         }
2171         if (gl->gl_ops == &gfs2_inode_glops && gl->gl_object) {
2172                 if (!test_bit(GLF_LOCK, &gl->gl_flags) &&
2173                     list_empty(&gl->gl_holders)) {
2174                         error = dump_inode(gl->gl_object);
2175                         if (error)
2176                                 goto out;
2177                 } else {
2178                         error = -ENOBUFS;
2179                         printk(KERN_INFO "  Inode: busy\n");
2180                 }
2181         }
2182
2183         error = 0;
2184
2185 out:
2186         spin_unlock(&gl->gl_spin);
2187         return error;
2188 }
2189
2190 /**
2191  * gfs2_dump_lockstate - print out the current lockstate
2192  * @sdp: the filesystem
2193  * @ub: the buffer to copy the information into
2194  *
2195  * If @ub is NULL, dump the lockstate to the console.
2196  *
2197  */
2198
2199 static int gfs2_dump_lockstate(struct gfs2_sbd *sdp)
2200 {
2201         struct gfs2_glock *gl;
2202         unsigned int x;
2203         int error = 0;
2204
2205         for (x = 0; x < GFS2_GL_HASH_SIZE; x++) {
2206
2207                 read_lock(&gl_hash_locks[x]);
2208
2209                 list_for_each_entry(gl, &gl_hash_table[x].hb_list, gl_list) {
2210                         if (test_bit(GLF_PLUG, &gl->gl_flags))
2211                                 continue;
2212                         if (gl->gl_sbd != sdp)
2213                                 continue;
2214
2215                         error = dump_glock(gl);
2216                         if (error)
2217                                 break;
2218                 }
2219
2220                 read_unlock(&gl_hash_locks[x]);
2221
2222                 if (error)
2223                         break;
2224         }
2225
2226
2227         return error;
2228 }
2229
2230 int __init gfs2_glock_init(void)
2231 {
2232         unsigned i;
2233         for(i = 0; i < GFS2_GL_HASH_SIZE; i++) {
2234                 rwlock_init(&gl_hash_locks[i]);
2235                 INIT_LIST_HEAD(&gl_hash_table[i].hb_list);
2236         }
2237         return 0;
2238 }
2239