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 <linux/list.h>
  22 #include <asm/uaccess.h>
  23
  24 #include "gfs2.h"
  25 #include "lm_interface.h"
  26 #include "incore.h"
  27 #include "glock.h"
  28 #include "glops.h"
  29 #include "inode.h"
  30 #include "lm.h"
  31 #include "lops.h"
  32 #include "meta_io.h"
  33 #include "quota.h"
  34 #include "super.h"
  35 #include "util.h"
  36
  37 struct greedy {
  38         struct gfs2_holder gr_gh;
  39         struct work_struct gr_work;
  40 };
  41
  42 struct gfs2_gl_hash_bucket {
  43         struct hlist_head hb_list;
  44 };
  45
  46 typedef void (*glock_examiner) (struct gfs2_glock * gl);
  47
  48 static int gfs2_dump_lockstate(struct gfs2_sbd *sdp);
  49 static int dump_glock(struct gfs2_glock *gl);
  50 static int dump_inode(struct gfs2_inode *ip);
  51
  52 #define GFS2_GL_HASH_SHIFT      15
  53 #define GFS2_GL_HASH_SIZE       (1 << GFS2_GL_HASH_SHIFT)
  54 #define GFS2_GL_HASH_MASK       (GFS2_GL_HASH_SIZE - 1)
  55
  56 static struct gfs2_gl_hash_bucket gl_hash_table[GFS2_GL_HASH_SIZE];
  57
  58 /*
  59  * Despite what you might think, the numbers below are not arbitrary :-)
  60  * They are taken from the ipv4 routing hash code, which is well tested
  61  * and thus should be nearly optimal. Later on we might tweek the numbers
  62  * but for now this should be fine.
  63  *
  64  * The reason for putting the locks in a separate array from the list heads
  65  * is that we can have fewer locks than list heads and save memory. We use
  66  * the same hash function for both, but with a different hash mask.
  67  */
  68 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK) || \
  69         defined(CONFIG_PROVE_LOCKING)
  70
  71 #ifdef CONFIG_LOCKDEP
  72 # define GL_HASH_LOCK_SZ        256
  73 #else
  74 # if NR_CPUS >= 32
  75 #  define GL_HASH_LOCK_SZ       4096
  76 # elif NR_CPUS >= 16
  77 #  define GL_HASH_LOCK_SZ       2048
  78 # elif NR_CPUS >= 8
  79 #  define GL_HASH_LOCK_SZ       1024
  80 # elif NR_CPUS >= 4
  81 #  define GL_HASH_LOCK_SZ       512
  82 # else
  83 #  define GL_HASH_LOCK_SZ       256
  84 # endif
  85 #endif
  86
  87 /* We never want more locks than chains */
  88 #if GFS2_GL_HASH_SIZE < GL_HASH_LOCK_SZ
  89 # undef GL_HASH_LOCK_SZ
  90 # define GL_HASH_LOCK_SZ GFS2_GL_HASH_SIZE
  91 #endif
  92
  93 static rwlock_t gl_hash_locks[GL_HASH_LOCK_SZ];
  94
  95 static inline rwlock_t *gl_lock_addr(unsigned int x)
  96 {
  97         return &gl_hash_locks[x & (GL_HASH_LOCK_SZ-1)];
  98 }
  99 #else /* not SMP, so no spinlocks required */
 100 static inline rwlock_t *gl_lock_addr(x)
 101 {
 102         return NULL;
 103 }
 104 #endif
 105
 106 /**
 107  * relaxed_state_ok - is a requested lock compatible with the current lock mode?
 108  * @actual: the current state of the lock
 109  * @requested: the lock state that was requested by the caller
 110  * @flags: the modifier flags passed in by the caller
 111  *
 112  * Returns: 1 if the locks are compatible, 0 otherwise
 113  */
 114
 115 static inline int relaxed_state_ok(unsigned int actual, unsigned requested,
 116                                    int flags)
 117 {
 118         if (actual == requested)
 119                 return 1;
 120
 121         if (flags & GL_EXACT)
 122                 return 0;
 123
 124         if (actual == LM_ST_EXCLUSIVE && requested == LM_ST_SHARED)
 125                 return 1;
 126
 127         if (actual != LM_ST_UNLOCKED && (flags & LM_FLAG_ANY))
 128                 return 1;
 129
 130         return 0;
 131 }
 132
 133 /**
 134  * gl_hash() - Turn glock number into hash bucket number
 135  * @lock: The glock number
 136  *
 137  * Returns: The number of the corresponding hash bucket
 138  */
 139
 140 static unsigned int gl_hash(const struct gfs2_sbd *sdp,
 141                             const struct lm_lockname *name)
 142 {
 143         unsigned int h;
 144
 145         h = jhash(&name->ln_number, sizeof(u64), 0);
 146         h = jhash(&name->ln_type, sizeof(unsigned int), h);
 147         h = jhash(&sdp, sizeof(struct gfs2_sbd *), h);
 148         h &= GFS2_GL_HASH_MASK;
 149
 150         return h;
 151 }
 152
 153 /**
 154  * glock_free() - Perform a few checks and then release struct gfs2_glock
 155  * @gl: The glock to release
 156  *
 157  * Also calls lock module to release its internal structure for this glock.
 158  *
 159  */
 160
 161 static void glock_free(struct gfs2_glock *gl)
 162 {
 163         struct gfs2_sbd *sdp = gl->gl_sbd;
 164         struct inode *aspace = gl->gl_aspace;
 165
 166         gfs2_lm_put_lock(sdp, gl->gl_lock);
 167
 168         if (aspace)
 169                 gfs2_aspace_put(aspace);
 170
 171         kmem_cache_free(gfs2_glock_cachep, gl);
 172 }
 173
 174 /**
 175  * gfs2_glock_hold() - increment reference count on glock
 176  * @gl: The glock to hold
 177  *
 178  */
 179
 180 void gfs2_glock_hold(struct gfs2_glock *gl)
 181 {
 182         kref_get(&gl->gl_ref);
 183 }
 184
 185 /* All work is done after the return from kref_put() so we
 186    can release the write_lock before the free. */
 187
 188 static void kill_glock(struct kref *kref)
 189 {
 190         struct gfs2_glock *gl = container_of(kref, struct gfs2_glock, gl_ref);
 191         struct gfs2_sbd *sdp = gl->gl_sbd;
 192
 193         gfs2_assert(sdp, gl->gl_state == LM_ST_UNLOCKED);
 194         gfs2_assert(sdp, list_empty(&gl->gl_reclaim));
 195         gfs2_assert(sdp, list_empty(&gl->gl_holders));
 196         gfs2_assert(sdp, list_empty(&gl->gl_waiters1));
 197         gfs2_assert(sdp, list_empty(&gl->gl_waiters2));
 198         gfs2_assert(sdp, list_empty(&gl->gl_waiters3));
 199 }
 200
 201 /**
 202  * gfs2_glock_put() - Decrement reference count on glock
 203  * @gl: The glock to put
 204  *
 205  */
 206
 207 int gfs2_glock_put(struct gfs2_glock *gl)
 208 {
 209         int rv = 0;
 210
 211         write_lock(gl_lock_addr(gl->gl_hash));
 212         if (kref_put(&gl->gl_ref, kill_glock)) {
 213                 hlist_del(&gl->gl_list);
 214                 write_unlock(gl_lock_addr(gl->gl_hash));
 215                 BUG_ON(spin_is_locked(&gl->gl_spin));
 216                 glock_free(gl);
 217                 rv = 1;
 218                 goto out;
 219         }
 220         write_unlock(gl_lock_addr(gl->gl_hash));
 221 out:
 222         return rv;
 223 }
 224
 225 /**
 226  * queue_empty - check to see if a glock's queue is empty
 227  * @gl: the glock
 228  * @head: the head of the queue to check
 229  *
 230  * This function protects the list in the event that a process already
 231  * has a holder on the list and is adding a second holder for itself.
 232  * The glmutex lock is what generally prevents processes from working
 233  * on the same glock at once, but the special case of adding a second
 234  * holder for yourself ("recursive" locking) doesn't involve locking
 235  * glmutex, making the spin lock necessary.
 236  *
 237  * Returns: 1 if the queue is empty
 238  */
 239
 240 static inline int queue_empty(struct gfs2_glock *gl, struct list_head *head)
 241 {
 242         int empty;
 243         spin_lock(&gl->gl_spin);
 244         empty = list_empty(head);
 245         spin_unlock(&gl->gl_spin);
 246         return empty;
 247 }
 248
 249 /**
 250  * search_bucket() - Find struct gfs2_glock by lock number
 251  * @bucket: the bucket to search
 252  * @name: The lock name
 253  *
 254  * Returns: NULL, or the struct gfs2_glock with the requested number
 255  */
 256
 257 static struct gfs2_glock *search_bucket(unsigned int hash,
 258                                         const struct gfs2_sbd *sdp,
 259                                         const struct lm_lockname *name)
 260 {
 261         struct gfs2_glock *gl;
 262         struct hlist_node *h;
 263
 264         hlist_for_each_entry(gl, h, &gl_hash_table[hash].hb_list, gl_list) {
 265                 if (!lm_name_equal(&gl->gl_name, name))
 266                         continue;
 267                 if (gl->gl_sbd != sdp)
 268                         continue;
 269
 270                 kref_get(&gl->gl_ref);
 271
 272                 return gl;
 273         }
 274
 275         return NULL;
 276 }
 277
 278 /**
 279  * gfs2_glock_find() - Find glock by lock number
 280  * @sdp: The GFS2 superblock
 281  * @name: The lock name
 282  *
 283  * Returns: NULL, or the struct gfs2_glock with the requested number
 284  */
 285
 286 static struct gfs2_glock *gfs2_glock_find(const struct gfs2_sbd *sdp,
 287                                           const struct lm_lockname *name)
 288 {
 289         unsigned int hash = gl_hash(sdp, name);
 290         struct gfs2_glock *gl;
 291
 292         read_lock(gl_lock_addr(hash));
 293         gl = search_bucket(hash, sdp, name);
 294         read_unlock(gl_lock_addr(hash));
 295
 296         return gl;
 297 }
 298
 299 /**
 300  * gfs2_glock_get() - Get a glock, or create one if one doesn't exist
 301  * @sdp: The GFS2 superblock
 302  * @number: the lock number
 303  * @glops: The glock_operations to use
 304  * @create: If 0, don't create the glock if it doesn't exist
 305  * @glp: the glock is returned here
 306  *
 307  * This does not lock a glock, just finds/creates structures for one.
 308  *
 309  * Returns: errno
 310  */
 311
 312 int gfs2_glock_get(struct gfs2_sbd *sdp, u64 number,
 313                    const struct gfs2_glock_operations *glops, int create,
 314                    struct gfs2_glock **glp)
 315 {
 316         struct lm_lockname name = { .ln_number = number, .ln_type = glops->go_type };
 317         struct gfs2_glock *gl, *tmp;
 318         unsigned int hash = gl_hash(sdp, &name);
 319         int error;
 320
 321         read_lock(gl_lock_addr(hash));
 322         gl = search_bucket(hash, sdp, &name);
 323         read_unlock(gl_lock_addr(hash));
 324
 325         if (gl || !create) {
 326                 *glp = gl;
 327                 return 0;
 328         }
 329
 330         gl = kmem_cache_alloc(gfs2_glock_cachep, GFP_KERNEL);
 331         if (!gl)
 332                 return -ENOMEM;
 333
 334         gl->gl_flags = 0;
 335         gl->gl_name = name;
 336         kref_init(&gl->gl_ref);
 337         gl->gl_state = LM_ST_UNLOCKED;
 338         gl->gl_hash = hash;
 339         gl->gl_owner = NULL;
 340         gl->gl_ip = 0;
 341         gl->gl_ops = glops;
 342         gl->gl_req_gh = NULL;
 343         gl->gl_req_bh = NULL;
 344         gl->gl_vn = 0;
 345         gl->gl_stamp = jiffies;
 346         gl->gl_object = NULL;
 347         gl->gl_sbd = sdp;
 348         gl->gl_aspace = NULL;
 349         lops_init_le(&gl->gl_le, &gfs2_glock_lops);
 350
 351         /* If this glock protects actual on-disk data or metadata blocks,
 352            create a VFS inode to manage the pages/buffers holding them. */
 353         if (glops == &gfs2_inode_glops || glops == &gfs2_rgrp_glops) {
 354                 gl->gl_aspace = gfs2_aspace_get(sdp);
 355                 if (!gl->gl_aspace) {
 356                         error = -ENOMEM;
 357                         goto fail;
 358                 }
 359         }
 360
 361         error = gfs2_lm_get_lock(sdp, &name, &gl->gl_lock);
 362         if (error)
 363                 goto fail_aspace;
 364
 365         write_lock(gl_lock_addr(hash));
 366         tmp = search_bucket(hash, sdp, &name);
 367         if (tmp) {
 368                 write_unlock(gl_lock_addr(hash));
 369                 glock_free(gl);
 370                 gl = tmp;
 371         } else {
 372                 hlist_add_head(&gl->gl_list, &gl_hash_table[hash].hb_list);
 373                 write_unlock(gl_lock_addr(hash));
 374         }
 375
 376         *glp = gl;
 377
 378         return 0;
 379
 380 fail_aspace:
 381         if (gl->gl_aspace)
 382                 gfs2_aspace_put(gl->gl_aspace);
 383 fail:
 384         kmem_cache_free(gfs2_glock_cachep, gl);
 385         return error;
 386 }
 387
 388 /**
 389  * gfs2_holder_init - initialize a struct gfs2_holder in the default way
 390  * @gl: the glock
 391  * @state: the state we're requesting
 392  * @flags: the modifier flags
 393  * @gh: the holder structure
 394  *
 395  */
 396
 397 void gfs2_holder_init(struct gfs2_glock *gl, unsigned int state, unsigned flags,
 398                       struct gfs2_holder *gh)
 399 {
 400         INIT_LIST_HEAD(&gh->gh_list);
 401         gh->gh_gl = gl;
 402         gh->gh_ip = (unsigned long)__builtin_return_address(0);
 403         gh->gh_owner = current;
 404         gh->gh_state = state;
 405         gh->gh_flags = flags;
 406         gh->gh_error = 0;
 407         gh->gh_iflags = 0;
 408         init_completion(&gh->gh_wait);
 409
 410         if (gh->gh_state == LM_ST_EXCLUSIVE)
 411                 gh->gh_flags |= GL_LOCAL_EXCL;
 412
 413         gfs2_glock_hold(gl);
 414 }
 415
 416 /**
 417  * gfs2_holder_reinit - reinitialize a struct gfs2_holder so we can requeue it
 418  * @state: the state we're requesting
 419  * @flags: the modifier flags
 420  * @gh: the holder structure
 421  *
 422  * Don't mess with the glock.
 423  *
 424  */
 425
 426 void gfs2_holder_reinit(unsigned int state, unsigned flags, struct gfs2_holder *gh)
 427 {
 428         gh->gh_state = state;
 429         gh->gh_flags = flags;
 430         if (gh->gh_state == LM_ST_EXCLUSIVE)
 431                 gh->gh_flags |= GL_LOCAL_EXCL;
 432
 433         gh->gh_iflags &= 1 << HIF_ALLOCED;
 434         gh->gh_ip = (unsigned long)__builtin_return_address(0);
 435 }
 436
 437 /**
 438  * gfs2_holder_uninit - uninitialize a holder structure (drop glock reference)
 439  * @gh: the holder structure
 440  *
 441  */
 442
 443 void gfs2_holder_uninit(struct gfs2_holder *gh)
 444 {
 445         gfs2_glock_put(gh->gh_gl);
 446         gh->gh_gl = NULL;
 447         gh->gh_ip = 0;
 448 }
 449
 450 /**
 451  * gfs2_holder_get - get a struct gfs2_holder structure
 452  * @gl: the glock
 453  * @state: the state we're requesting
 454  * @flags: the modifier flags
 455  * @gfp_flags:
 456  *
 457  * Figure out how big an impact this function has.  Either:
 458  * 1) Replace it with a cache of structures hanging off the struct gfs2_sbd
 459  * 2) Leave it like it is
 460  *
 461  * Returns: the holder structure, NULL on ENOMEM
 462  */
 463
 464 static struct gfs2_holder *gfs2_holder_get(struct gfs2_glock *gl,
 465                                            unsigned int state,
 466                                            int flags, gfp_t gfp_flags)
 467 {
 468         struct gfs2_holder *gh;
 469
 470         gh = kmalloc(sizeof(struct gfs2_holder), gfp_flags);
 471         if (!gh)
 472                 return NULL;
 473
 474         gfs2_holder_init(gl, state, flags, gh);
 475         set_bit(HIF_ALLOCED, &gh->gh_iflags);
 476         gh->gh_ip = (unsigned long)__builtin_return_address(0);
 477         return gh;
 478 }
 479
 480 /**
 481  * gfs2_holder_put - get rid of a struct gfs2_holder structure
 482  * @gh: the holder structure
 483  *
 484  */
 485
 486 static void gfs2_holder_put(struct gfs2_holder *gh)
 487 {
 488         gfs2_holder_uninit(gh);
 489         kfree(gh);
 490 }
 491
 492 /**
 493  * rq_mutex - process a mutex request in the queue
 494  * @gh: the glock holder
 495  *
 496  * Returns: 1 if the queue is blocked
 497  */
 498
 499 static int rq_mutex(struct gfs2_holder *gh)
 500 {
 501         struct gfs2_glock *gl = gh->gh_gl;
 502
 503         list_del_init(&gh->gh_list);
 504         /*  gh->gh_error never examined.  */
 505         set_bit(GLF_LOCK, &gl->gl_flags);
 506         complete(&gh->gh_wait);
 507
 508         return 1;
 509 }
 510
 511 /**
 512  * rq_promote - process a promote request in the queue
 513  * @gh: the glock holder
 514  *
 515  * Acquire a new inter-node lock, or change a lock state to more restrictive.
 516  *
 517  * Returns: 1 if the queue is blocked
 518  */
 519
 520 static int rq_promote(struct gfs2_holder *gh)
 521 {
 522         struct gfs2_glock *gl = gh->gh_gl;
 523         struct gfs2_sbd *sdp = gl->gl_sbd;
 524         const struct gfs2_glock_operations *glops = gl->gl_ops;
 525
 526         if (!relaxed_state_ok(gl->gl_state, gh->gh_state, gh->gh_flags)) {
 527                 if (list_empty(&gl->gl_holders)) {
 528                         gl->gl_req_gh = gh;
 529                         set_bit(GLF_LOCK, &gl->gl_flags);
 530                         spin_unlock(&gl->gl_spin);
 531
 532                         if (atomic_read(&sdp->sd_reclaim_count) >
 533                             gfs2_tune_get(sdp, gt_reclaim_limit) &&
 534                             !(gh->gh_flags & LM_FLAG_PRIORITY)) {
 535                                 gfs2_reclaim_glock(sdp);
 536                                 gfs2_reclaim_glock(sdp);
 537                         }
 538
 539                         glops->go_xmote_th(gl, gh->gh_state, gh->gh_flags);
 540                         spin_lock(&gl->gl_spin);
 541                 }
 542                 return 1;
 543         }
 544
 545         if (list_empty(&gl->gl_holders)) {
 546                 set_bit(HIF_FIRST, &gh->gh_iflags);
 547                 set_bit(GLF_LOCK, &gl->gl_flags);
 548         } else {
 549                 struct gfs2_holder *next_gh;
 550                 if (gh->gh_flags & GL_LOCAL_EXCL)
 551                         return 1;
 552                 next_gh = list_entry(gl->gl_holders.next, struct gfs2_holder,
 553                                      gh_list);
 554                 if (next_gh->gh_flags & GL_LOCAL_EXCL)
 555                          return 1;
 556         }
 557
 558         list_move_tail(&gh->gh_list, &gl->gl_holders);
 559         gh->gh_error = 0;
 560         set_bit(HIF_HOLDER, &gh->gh_iflags);
 561
 562         complete(&gh->gh_wait);
 563
 564         return 0;
 565 }
 566
 567 /**
 568  * rq_demote - process a demote request in the queue
 569  * @gh: the glock holder
 570  *
 571  * Returns: 1 if the queue is blocked
 572  */
 573
 574 static int rq_demote(struct gfs2_holder *gh)
 575 {
 576         struct gfs2_glock *gl = gh->gh_gl;
 577         const struct gfs2_glock_operations *glops = gl->gl_ops;
 578
 579         if (!list_empty(&gl->gl_holders))
 580                 return 1;
 581
 582         if (gl->gl_state == gh->gh_state || gl->gl_state == LM_ST_UNLOCKED) {
 583                 list_del_init(&gh->gh_list);
 584                 gh->gh_error = 0;
 585                 spin_unlock(&gl->gl_spin);
 586                 if (test_bit(HIF_DEALLOC, &gh->gh_iflags))
 587                         gfs2_holder_put(gh);
 588                 else
 589                         complete(&gh->gh_wait);
 590                 spin_lock(&gl->gl_spin);
 591         } else {
 592                 gl->gl_req_gh = gh;
 593                 set_bit(GLF_LOCK, &gl->gl_flags);
 594                 spin_unlock(&gl->gl_spin);
 595
 596                 if (gh->gh_state == LM_ST_UNLOCKED ||
 597                     gl->gl_state != LM_ST_EXCLUSIVE)
 598                         glops->go_drop_th(gl);
 599                 else
 600                         glops->go_xmote_th(gl, gh->gh_state, gh->gh_flags);
 601
 602                 spin_lock(&gl->gl_spin);
 603         }
 604
 605         return 0;
 606 }
 607
 608 /**
 609  * rq_greedy - process a queued request to drop greedy status
 610  * @gh: the glock holder
 611  *
 612  * Returns: 1 if the queue is blocked
 613  */
 614
 615 static int rq_greedy(struct gfs2_holder *gh)
 616 {
 617         struct gfs2_glock *gl = gh->gh_gl;
 618
 619         list_del_init(&gh->gh_list);
 620         /*  gh->gh_error never examined.  */
 621         clear_bit(GLF_GREEDY, &gl->gl_flags);
 622         spin_unlock(&gl->gl_spin);
 623
 624         gfs2_holder_uninit(gh);
 625         kfree(container_of(gh, struct greedy, gr_gh));
 626
 627         spin_lock(&gl->gl_spin);
 628
 629         return 0;
 630 }
 631
 632 /**
 633  * run_queue - process holder structures on a glock
 634  * @gl: the glock
 635  *
 636  */
 637 static void run_queue(struct gfs2_glock *gl)
 638 {
 639         struct gfs2_holder *gh;
 640         int blocked = 1;
 641
 642         for (;;) {
 643                 if (test_bit(GLF_LOCK, &gl->gl_flags))
 644                         break;
 645
 646                 if (!list_empty(&gl->gl_waiters1)) {
 647                         gh = list_entry(gl->gl_waiters1.next,
 648                                         struct gfs2_holder, gh_list);
 649
 650                         if (test_bit(HIF_MUTEX, &gh->gh_iflags))
 651                                 blocked = rq_mutex(gh);
 652                         else
 653                                 gfs2_assert_warn(gl->gl_sbd, 0);
 654
 655                 } else if (!list_empty(&gl->gl_waiters2) &&
 656                            !test_bit(GLF_SKIP_WAITERS2, &gl->gl_flags)) {
 657                         gh = list_entry(gl->gl_waiters2.next,
 658                                         struct gfs2_holder, gh_list);
 659
 660                         if (test_bit(HIF_DEMOTE, &gh->gh_iflags))
 661                                 blocked = rq_demote(gh);
 662                         else if (test_bit(HIF_GREEDY, &gh->gh_iflags))
 663                                 blocked = rq_greedy(gh);
 664                         else
 665                                 gfs2_assert_warn(gl->gl_sbd, 0);
 666
 667                 } else if (!list_empty(&gl->gl_waiters3)) {
 668                         gh = list_entry(gl->gl_waiters3.next,
 669                                         struct gfs2_holder, gh_list);
 670
 671                         if (test_bit(HIF_PROMOTE, &gh->gh_iflags))
 672                                 blocked = rq_promote(gh);
 673                         else
 674                                 gfs2_assert_warn(gl->gl_sbd, 0);
 675
 676                 } else
 677                         break;
 678
 679                 if (blocked)
 680                         break;
 681         }
 682 }
 683
 684 /**
 685  * gfs2_glmutex_lock - acquire a local lock on a glock
 686  * @gl: the glock
 687  *
 688  * Gives caller exclusive access to manipulate a glock structure.
 689  */
 690
 691 static void gfs2_glmutex_lock(struct gfs2_glock *gl)
 692 {
 693         struct gfs2_holder gh;
 694
 695         gfs2_holder_init(gl, 0, 0, &gh);
 696         set_bit(HIF_MUTEX, &gh.gh_iflags);
 697
 698         spin_lock(&gl->gl_spin);
 699         if (test_and_set_bit(GLF_LOCK, &gl->gl_flags)) {
 700                 list_add_tail(&gh.gh_list, &gl->gl_waiters1);
 701         } else {
 702                 gl->gl_owner = current;
 703                 gl->gl_ip = (unsigned long)__builtin_return_address(0);
 704                 complete(&gh.gh_wait);
 705         }
 706         spin_unlock(&gl->gl_spin);
 707
 708         wait_for_completion(&gh.gh_wait);
 709         gfs2_holder_uninit(&gh);
 710 }
 711
 712 /**
 713  * gfs2_glmutex_trylock - try to acquire a local lock on a glock
 714  * @gl: the glock
 715  *
 716  * Returns: 1 if the glock is acquired
 717  */
 718
 719 static int gfs2_glmutex_trylock(struct gfs2_glock *gl)
 720 {
 721         int acquired = 1;
 722
 723         spin_lock(&gl->gl_spin);
 724         if (test_and_set_bit(GLF_LOCK, &gl->gl_flags)) {
 725                 acquired = 0;
 726         } else {
 727                 gl->gl_owner = current;
 728                 gl->gl_ip = (unsigned long)__builtin_return_address(0);
 729         }
 730         spin_unlock(&gl->gl_spin);
 731
 732         return acquired;
 733 }
 734
 735 /**
 736  * gfs2_glmutex_unlock - release a local lock on a glock
 737  * @gl: the glock
 738  *
 739  */
 740
 741 static void gfs2_glmutex_unlock(struct gfs2_glock *gl)
 742 {
 743         spin_lock(&gl->gl_spin);
 744         clear_bit(GLF_LOCK, &gl->gl_flags);
 745         gl->gl_owner = NULL;
 746         gl->gl_ip = 0;
 747         run_queue(gl);
 748         BUG_ON(!spin_is_locked(&gl->gl_spin));
 749         spin_unlock(&gl->gl_spin);
 750 }
 751
 752 /**
 753  * handle_callback - add a demote request to a lock's queue
 754  * @gl: the glock
 755  * @state: the state the caller wants us to change to
 756  *
 757  * Note: This may fail sliently if we are out of memory.
 758  */
 759
 760 static void handle_callback(struct gfs2_glock *gl, unsigned int state)
 761 {
 762         struct gfs2_holder *gh, *new_gh = NULL;
 763
 764 restart:
 765         spin_lock(&gl->gl_spin);
 766
 767         list_for_each_entry(gh, &gl->gl_waiters2, gh_list) {
 768                 if (test_bit(HIF_DEMOTE, &gh->gh_iflags) &&
 769                     gl->gl_req_gh != gh) {
 770                         if (gh->gh_state != state)
 771                                 gh->gh_state = LM_ST_UNLOCKED;
 772                         goto out;
 773                 }
 774         }
 775
 776         if (new_gh) {
 777                 list_add_tail(&new_gh->gh_list, &gl->gl_waiters2);
 778                 new_gh = NULL;
 779         } else {
 780                 spin_unlock(&gl->gl_spin);
 781
 782                 new_gh = gfs2_holder_get(gl, state, LM_FLAG_TRY, GFP_KERNEL);
 783                 if (!new_gh)
 784                         return;
 785                 set_bit(HIF_DEMOTE, &new_gh->gh_iflags);
 786                 set_bit(HIF_DEALLOC, &new_gh->gh_iflags);
 787
 788                 goto restart;
 789         }
 790
 791 out:
 792         spin_unlock(&gl->gl_spin);
 793
 794         if (new_gh)
 795                 gfs2_holder_put(new_gh);
 796 }
 797
 798 void gfs2_glock_inode_squish(struct inode *inode)
 799 {
 800         struct gfs2_holder gh;
 801         struct gfs2_glock *gl = GFS2_I(inode)->i_gl;
 802         gfs2_holder_init(gl, LM_ST_UNLOCKED, 0, &gh);
 803         set_bit(HIF_DEMOTE, &gh.gh_iflags);
 804         spin_lock(&gl->gl_spin);
 805         gfs2_assert(inode->i_sb->s_fs_info, list_empty(&gl->gl_holders));
 806         list_add_tail(&gh.gh_list, &gl->gl_waiters2);
 807         run_queue(gl);
 808         spin_unlock(&gl->gl_spin);
 809         wait_for_completion(&gh.gh_wait);
 810         gfs2_holder_uninit(&gh);
 811 }
 812
 813 /**
 814  * state_change - record that the glock is now in a different state
 815  * @gl: the glock
 816  * @new_state the new state
 817  *
 818  */
 819
 820 static void state_change(struct gfs2_glock *gl, unsigned int new_state)
 821 {
 822         int held1, held2;
 823
 824         held1 = (gl->gl_state != LM_ST_UNLOCKED);
 825         held2 = (new_state != LM_ST_UNLOCKED);
 826
 827         if (held1 != held2) {
 828                 if (held2)
 829                         gfs2_glock_hold(gl);
 830                 else
 831                         gfs2_glock_put(gl);
 832         }
 833
 834         gl->gl_state = new_state;
 835 }
 836
 837 /**
 838  * xmote_bh - Called after the lock module is done acquiring a lock
 839  * @gl: The glock in question
 840  * @ret: the int returned from the lock module
 841  *
 842  */
 843
 844 static void xmote_bh(struct gfs2_glock *gl, unsigned int ret)
 845 {
 846         struct gfs2_sbd *sdp = gl->gl_sbd;
 847         const struct gfs2_glock_operations *glops = gl->gl_ops;
 848         struct gfs2_holder *gh = gl->gl_req_gh;
 849         int prev_state = gl->gl_state;
 850         int op_done = 1;
 851
 852         gfs2_assert_warn(sdp, test_bit(GLF_LOCK, &gl->gl_flags));
 853         gfs2_assert_warn(sdp, queue_empty(gl, &gl->gl_holders));
 854         gfs2_assert_warn(sdp, !(ret & LM_OUT_ASYNC));
 855
 856         state_change(gl, ret & LM_OUT_ST_MASK);
 857
 858         if (prev_state != LM_ST_UNLOCKED && !(ret & LM_OUT_CACHEABLE)) {
 859                 if (glops->go_inval)
 860                         glops->go_inval(gl, DIO_METADATA | DIO_DATA);
 861         } else if (gl->gl_state == LM_ST_DEFERRED) {
 862                 /* We might not want to do this here.
 863                    Look at moving to the inode glops. */
 864                 if (glops->go_inval)
 865                         glops->go_inval(gl, DIO_DATA);
 866         }
 867
 868         /*  Deal with each possible exit condition  */
 869
 870         if (!gh)
 871                 gl->gl_stamp = jiffies;
 872         else if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags))) {
 873                 spin_lock(&gl->gl_spin);
 874                 list_del_init(&gh->gh_list);
 875                 gh->gh_error = -EIO;
 876                 spin_unlock(&gl->gl_spin);
 877         } else if (test_bit(HIF_DEMOTE, &gh->gh_iflags)) {
 878                 spin_lock(&gl->gl_spin);
 879                 list_del_init(&gh->gh_list);
 880                 if (gl->gl_state == gh->gh_state ||
 881                     gl->gl_state == LM_ST_UNLOCKED) {
 882                         gh->gh_error = 0;
 883                 } else {
 884                         if (gfs2_assert_warn(sdp, gh->gh_flags &
 885                                         (LM_FLAG_TRY | LM_FLAG_TRY_1CB)) == -1)
 886                                 fs_warn(sdp, "ret = 0x%.8X\n", ret);
 887                         gh->gh_error = GLR_TRYFAILED;
 888                 }
 889                 spin_unlock(&gl->gl_spin);
 890
 891                 if (ret & LM_OUT_CANCELED)
 892                         handle_callback(gl, LM_ST_UNLOCKED);
 893
 894         } else if (ret & LM_OUT_CANCELED) {
 895                 spin_lock(&gl->gl_spin);
 896                 list_del_init(&gh->gh_list);
 897                 gh->gh_error = GLR_CANCELED;
 898                 spin_unlock(&gl->gl_spin);
 899
 900         } else if (relaxed_state_ok(gl->gl_state, gh->gh_state, gh->gh_flags)) {
 901                 spin_lock(&gl->gl_spin);
 902                 list_move_tail(&gh->gh_list, &gl->gl_holders);
 903                 gh->gh_error = 0;
 904                 set_bit(HIF_HOLDER, &gh->gh_iflags);
 905                 spin_unlock(&gl->gl_spin);
 906
 907                 set_bit(HIF_FIRST, &gh->gh_iflags);
 908
 909                 op_done = 0;
 910
 911         } else if (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)) {
 912                 spin_lock(&gl->gl_spin);
 913                 list_del_init(&gh->gh_list);
 914                 gh->gh_error = GLR_TRYFAILED;
 915                 spin_unlock(&gl->gl_spin);
 916
 917         } else {
 918                 if (gfs2_assert_withdraw(sdp, 0) == -1)
 919                         fs_err(sdp, "ret = 0x%.8X\n", ret);
 920         }
 921
 922         if (glops->go_xmote_bh)
 923                 glops->go_xmote_bh(gl);
 924
 925         if (op_done) {
 926                 spin_lock(&gl->gl_spin);
 927                 gl->gl_req_gh = NULL;
 928                 gl->gl_req_bh = NULL;
 929                 clear_bit(GLF_LOCK, &gl->gl_flags);
 930                 run_queue(gl);
 931                 spin_unlock(&gl->gl_spin);
 932         }
 933
 934         gfs2_glock_put(gl);
 935
 936         if (gh) {
 937                 if (test_bit(HIF_DEALLOC, &gh->gh_iflags))
 938                         gfs2_holder_put(gh);
 939                 else
 940                         complete(&gh->gh_wait);
 941         }
 942 }
 943
 944 /**
 945  * gfs2_glock_xmote_th - Call into the lock module to acquire or change a glock
 946  * @gl: The glock in question
 947  * @state: the requested state
 948  * @flags: modifier flags to the lock call
 949  *
 950  */
 951
 952 void gfs2_glock_xmote_th(struct gfs2_glock *gl, unsigned int state, int flags)
 953 {
 954         struct gfs2_sbd *sdp = gl->gl_sbd;
 955         const struct gfs2_glock_operations *glops = gl->gl_ops;
 956         int lck_flags = flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB |
 957                                  LM_FLAG_NOEXP | LM_FLAG_ANY |
 958                                  LM_FLAG_PRIORITY);
 959         unsigned int lck_ret;
 960
 961         gfs2_assert_warn(sdp, test_bit(GLF_LOCK, &gl->gl_flags));
 962         gfs2_assert_warn(sdp, queue_empty(gl, &gl->gl_holders));
 963         gfs2_assert_warn(sdp, state != LM_ST_UNLOCKED);
 964         gfs2_assert_warn(sdp, state != gl->gl_state);
 965
 966         if (gl->gl_state == LM_ST_EXCLUSIVE && glops->go_sync)
 967                 glops->go_sync(gl, DIO_METADATA | DIO_DATA | DIO_RELEASE);
 968
 969         gfs2_glock_hold(gl);
 970         gl->gl_req_bh = xmote_bh;
 971
 972         lck_ret = gfs2_lm_lock(sdp, gl->gl_lock, gl->gl_state, state, lck_flags);
 973
 974         if (gfs2_assert_withdraw(sdp, !(lck_ret & LM_OUT_ERROR)))
 975                 return;
 976
 977         if (lck_ret & LM_OUT_ASYNC)
 978                 gfs2_assert_warn(sdp, lck_ret == LM_OUT_ASYNC);
 979         else
 980                 xmote_bh(gl, lck_ret);
 981 }
 982
 983 /**
 984  * drop_bh - Called after a lock module unlock completes
 985  * @gl: the glock
 986  * @ret: the return status
 987  *
 988  * Doesn't wake up the process waiting on the struct gfs2_holder (if any)
 989  * Doesn't drop the reference on the glock the top half took out
 990  *
 991  */
 992
 993 static void drop_bh(struct gfs2_glock *gl, unsigned int ret)
 994 {
 995         struct gfs2_sbd *sdp = gl->gl_sbd;
 996         const struct gfs2_glock_operations *glops = gl->gl_ops;
 997         struct gfs2_holder *gh = gl->gl_req_gh;
 998
 999         clear_bit(GLF_PREFETCH, &gl->gl_flags);
1000
1001         gfs2_assert_warn(sdp, test_bit(GLF_LOCK, &gl->gl_flags));
1002         gfs2_assert_warn(sdp, queue_empty(gl, &gl->gl_holders));
1003         gfs2_assert_warn(sdp, !ret);
1004
1005         state_change(gl, LM_ST_UNLOCKED);
1006
1007         if (glops->go_inval)
1008                 glops->go_inval(gl, DIO_METADATA | DIO_DATA);
1009
1010         if (gh) {
1011                 spin_lock(&gl->gl_spin);
1012                 list_del_init(&gh->gh_list);
1013                 gh->gh_error = 0;
1014                 spin_unlock(&gl->gl_spin);
1015         }
1016
1017         if (glops->go_drop_bh)
1018                 glops->go_drop_bh(gl);
1019
1020         spin_lock(&gl->gl_spin);
1021         gl->gl_req_gh = NULL;
1022         gl->gl_req_bh = NULL;
1023         clear_bit(GLF_LOCK, &gl->gl_flags);
1024         run_queue(gl);
1025         spin_unlock(&gl->gl_spin);
1026
1027         gfs2_glock_put(gl);
1028
1029         if (gh) {
1030                 if (test_bit(HIF_DEALLOC, &gh->gh_iflags))
1031                         gfs2_holder_put(gh);
1032                 else
1033                         complete(&gh->gh_wait);
1034         }
1035 }
1036
1037 /**
1038  * gfs2_glock_drop_th - call into the lock module to unlock a lock
1039  * @gl: the glock
1040  *
1041  */
1042
1043 void gfs2_glock_drop_th(struct gfs2_glock *gl)
1044 {
1045         struct gfs2_sbd *sdp = gl->gl_sbd;
1046         const struct gfs2_glock_operations *glops = gl->gl_ops;
1047         unsigned int ret;
1048
1049         gfs2_assert_warn(sdp, test_bit(GLF_LOCK, &gl->gl_flags));
1050         gfs2_assert_warn(sdp, queue_empty(gl, &gl->gl_holders));
1051         gfs2_assert_warn(sdp, gl->gl_state != LM_ST_UNLOCKED);
1052
1053         if (gl->gl_state == LM_ST_EXCLUSIVE && glops->go_sync)
1054                 glops->go_sync(gl, DIO_METADATA | DIO_DATA | DIO_RELEASE);
1055
1056         gfs2_glock_hold(gl);
1057         gl->gl_req_bh = drop_bh;
1058
1059         ret = gfs2_lm_unlock(sdp, gl->gl_lock, gl->gl_state);
1060
1061         if (gfs2_assert_withdraw(sdp, !(ret & LM_OUT_ERROR)))
1062                 return;
1063
1064         if (!ret)
1065                 drop_bh(gl, ret);
1066         else
1067                 gfs2_assert_warn(sdp, ret == LM_OUT_ASYNC);
1068 }
1069
1070 /**
1071  * do_cancels - cancel requests for locks stuck waiting on an expire flag
1072  * @gh: the LM_FLAG_PRIORITY holder waiting to acquire the lock
1073  *
1074  * Don't cancel GL_NOCANCEL requests.
1075  */
1076
1077 static void do_cancels(struct gfs2_holder *gh)
1078 {
1079         struct gfs2_glock *gl = gh->gh_gl;
1080
1081         spin_lock(&gl->gl_spin);
1082
1083         while (gl->gl_req_gh != gh &&
1084                !test_bit(HIF_HOLDER, &gh->gh_iflags) &&
1085                !list_empty(&gh->gh_list)) {
1086                 if (gl->gl_req_bh && !(gl->gl_req_gh &&
1087                                      (gl->gl_req_gh->gh_flags & GL_NOCANCEL))) {
1088                         spin_unlock(&gl->gl_spin);
1089                         gfs2_lm_cancel(gl->gl_sbd, gl->gl_lock);
1090                         msleep(100);
1091                         spin_lock(&gl->gl_spin);
1092                 } else {
1093                         spin_unlock(&gl->gl_spin);
1094                         msleep(100);
1095                         spin_lock(&gl->gl_spin);
1096                 }
1097         }
1098
1099         spin_unlock(&gl->gl_spin);
1100 }
1101
1102 /**
1103  * glock_wait_internal - wait on a glock acquisition
1104  * @gh: the glock holder
1105  *
1106  * Returns: 0 on success
1107  */
1108
1109 static int glock_wait_internal(struct gfs2_holder *gh)
1110 {
1111         struct gfs2_glock *gl = gh->gh_gl;
1112         struct gfs2_sbd *sdp = gl->gl_sbd;
1113         const struct gfs2_glock_operations *glops = gl->gl_ops;
1114
1115         if (test_bit(HIF_ABORTED, &gh->gh_iflags))
1116                 return -EIO;
1117
1118         if (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)) {
1119                 spin_lock(&gl->gl_spin);
1120                 if (gl->gl_req_gh != gh &&
1121                     !test_bit(HIF_HOLDER, &gh->gh_iflags) &&
1122                     !list_empty(&gh->gh_list)) {
1123                         list_del_init(&gh->gh_list);
1124                         gh->gh_error = GLR_TRYFAILED;
1125                         run_queue(gl);
1126                         spin_unlock(&gl->gl_spin);
1127                         return gh->gh_error;
1128                 }
1129                 spin_unlock(&gl->gl_spin);
1130         }
1131
1132         if (gh->gh_flags & LM_FLAG_PRIORITY)
1133                 do_cancels(gh);
1134
1135         wait_for_completion(&gh->gh_wait);
1136
1137         if (gh->gh_error)
1138                 return gh->gh_error;
1139
1140         gfs2_assert_withdraw(sdp, test_bit(HIF_HOLDER, &gh->gh_iflags));
1141         gfs2_assert_withdraw(sdp, relaxed_state_ok(gl->gl_state, gh->gh_state,
1142                                                    gh->gh_flags));
1143
1144         if (test_bit(HIF_FIRST, &gh->gh_iflags)) {
1145                 gfs2_assert_warn(sdp, test_bit(GLF_LOCK, &gl->gl_flags));
1146
1147                 if (glops->go_lock) {
1148                         gh->gh_error = glops->go_lock(gh);
1149                         if (gh->gh_error) {
1150                                 spin_lock(&gl->gl_spin);
1151                                 list_del_init(&gh->gh_list);
1152                                 spin_unlock(&gl->gl_spin);
1153                         }
1154                 }
1155
1156                 spin_lock(&gl->gl_spin);
1157                 gl->gl_req_gh = NULL;
1158                 gl->gl_req_bh = NULL;
1159                 clear_bit(GLF_LOCK, &gl->gl_flags);
1160                 run_queue(gl);
1161                 spin_unlock(&gl->gl_spin);
1162         }
1163
1164         return gh->gh_error;
1165 }
1166
1167 static inline struct gfs2_holder *
1168 find_holder_by_owner(struct list_head *head, struct task_struct *owner)
1169 {
1170         struct gfs2_holder *gh;
1171
1172         list_for_each_entry(gh, head, gh_list) {
1173                 if (gh->gh_owner == owner)
1174                         return gh;
1175         }
1176
1177         return NULL;
1178 }
1179
1180 /**
1181  * add_to_queue - Add a holder to the wait queue (but look for recursion)
1182  * @gh: the holder structure to add
1183  *
1184  */
1185
1186 static void add_to_queue(struct gfs2_holder *gh)
1187 {
1188         struct gfs2_glock *gl = gh->gh_gl;
1189         struct gfs2_holder *existing;
1190
1191         BUG_ON(!gh->gh_owner);
1192
1193         existing = find_holder_by_owner(&gl->gl_holders, gh->gh_owner);
1194         if (existing) {
1195                 print_symbol(KERN_WARNING "original: %s\n", existing->gh_ip);
1196                 printk(KERN_INFO "pid : %d\n", existing->gh_owner->pid);
1197                 printk(KERN_INFO "lock type : %d lock state : %d\n",
1198                                 existing->gh_gl->gl_name.ln_type, existing->gh_gl->gl_state);
1199                 print_symbol(KERN_WARNING "new: %s\n", gh->gh_ip);
1200                 printk(KERN_INFO "pid : %d\n", gh->gh_owner->pid);
1201                 printk(KERN_INFO "lock type : %d lock state : %d\n",
1202                                 gl->gl_name.ln_type, gl->gl_state);
1203                 BUG();
1204         }
1205
1206         existing = find_holder_by_owner(&gl->gl_waiters3, gh->gh_owner);
1207         if (existing) {
1208                 print_symbol(KERN_WARNING "original: %s\n", existing->gh_ip);
1209                 print_symbol(KERN_WARNING "new: %s\n", gh->gh_ip);
1210                 BUG();
1211         }
1212
1213         if (gh->gh_flags & LM_FLAG_PRIORITY)
1214                 list_add(&gh->gh_list, &gl->gl_waiters3);
1215         else
1216                 list_add_tail(&gh->gh_list, &gl->gl_waiters3);
1217 }
1218
1219 /**
1220  * gfs2_glock_nq - enqueue a struct gfs2_holder onto a glock (acquire a glock)
1221  * @gh: the holder structure
1222  *
1223  * if (gh->gh_flags & GL_ASYNC), this never returns an error
1224  *
1225  * Returns: 0, GLR_TRYFAILED, or errno on failure
1226  */
1227
1228 int gfs2_glock_nq(struct gfs2_holder *gh)
1229 {
1230         struct gfs2_glock *gl = gh->gh_gl;
1231         struct gfs2_sbd *sdp = gl->gl_sbd;
1232         int error = 0;
1233
1234 restart:
1235         if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags))) {
1236                 set_bit(HIF_ABORTED, &gh->gh_iflags);
1237                 return -EIO;
1238         }
1239
1240         set_bit(HIF_PROMOTE, &gh->gh_iflags);
1241
1242         spin_lock(&gl->gl_spin);
1243         add_to_queue(gh);
1244         run_queue(gl);
1245         spin_unlock(&gl->gl_spin);
1246
1247         if (!(gh->gh_flags & GL_ASYNC)) {
1248                 error = glock_wait_internal(gh);
1249                 if (error == GLR_CANCELED) {
1250                         msleep(100);
1251                         goto restart;
1252                 }
1253         }
1254
1255         clear_bit(GLF_PREFETCH, &gl->gl_flags);
1256
1257         if (error == GLR_TRYFAILED && (gh->gh_flags & GL_DUMP))
1258                 dump_glock(gl);
1259
1260         return error;
1261 }
1262
1263 /**
1264  * gfs2_glock_poll - poll to see if an async request has been completed
1265  * @gh: the holder
1266  *
1267  * Returns: 1 if the request is ready to be gfs2_glock_wait()ed on
1268  */
1269
1270 int gfs2_glock_poll(struct gfs2_holder *gh)
1271 {
1272         struct gfs2_glock *gl = gh->gh_gl;
1273         int ready = 0;
1274
1275         spin_lock(&gl->gl_spin);
1276
1277         if (test_bit(HIF_HOLDER, &gh->gh_iflags))
1278                 ready = 1;
1279         else if (list_empty(&gh->gh_list)) {
1280                 if (gh->gh_error == GLR_CANCELED) {
1281                         spin_unlock(&gl->gl_spin);
1282                         msleep(100);
1283                         if (gfs2_glock_nq(gh))
1284                                 return 1;
1285                         return 0;
1286                 } else
1287                         ready = 1;
1288         }
1289
1290         spin_unlock(&gl->gl_spin);
1291
1292         return ready;
1293 }
1294
1295 /**
1296  * gfs2_glock_wait - wait for a lock acquisition that ended in a GLR_ASYNC
1297  * @gh: the holder structure
1298  *
1299  * Returns: 0, GLR_TRYFAILED, or errno on failure
1300  */
1301
1302 int gfs2_glock_wait(struct gfs2_holder *gh)
1303 {
1304         int error;
1305
1306         error = glock_wait_internal(gh);
1307         if (error == GLR_CANCELED) {
1308                 msleep(100);
1309                 gh->gh_flags &= ~GL_ASYNC;
1310                 error = gfs2_glock_nq(gh);
1311         }
1312
1313         return error;
1314 }
1315
1316 /**
1317  * gfs2_glock_dq - dequeue a struct gfs2_holder from a glock (release a glock)
1318  * @gh: the glock holder
1319  *
1320  */
1321
1322 void gfs2_glock_dq(struct gfs2_holder *gh)
1323 {
1324         struct gfs2_glock *gl = gh->gh_gl;
1325         const struct gfs2_glock_operations *glops = gl->gl_ops;
1326
1327         if (gh->gh_flags & GL_NOCACHE)
1328                 handle_callback(gl, LM_ST_UNLOCKED);
1329
1330         gfs2_glmutex_lock(gl);
1331
1332         spin_lock(&gl->gl_spin);
1333         list_del_init(&gh->gh_list);
1334
1335         if (list_empty(&gl->gl_holders)) {
1336                 spin_unlock(&gl->gl_spin);
1337
1338                 if (glops->go_unlock)
1339                         glops->go_unlock(gh);
1340
1341                 gl->gl_stamp = jiffies;
1342
1343                 spin_lock(&gl->gl_spin);
1344         }
1345
1346         clear_bit(GLF_LOCK, &gl->gl_flags);
1347         run_queue(gl);
1348         spin_unlock(&gl->gl_spin);
1349 }
1350
1351 /**
1352  * gfs2_glock_prefetch - Try to prefetch a glock
1353  * @gl: the glock
1354  * @state: the state to prefetch in
1355  * @flags: flags passed to go_xmote_th()
1356  *
1357  */
1358
1359 static void gfs2_glock_prefetch(struct gfs2_glock *gl, unsigned int state,
1360                                 int flags)
1361 {
1362         const struct gfs2_glock_operations *glops = gl->gl_ops;
1363
1364         spin_lock(&gl->gl_spin);
1365
1366         if (test_bit(GLF_LOCK, &gl->gl_flags) || !list_empty(&gl->gl_holders) ||
1367             !list_empty(&gl->gl_waiters1) || !list_empty(&gl->gl_waiters2) ||
1368             !list_empty(&gl->gl_waiters3) ||
1369             relaxed_state_ok(gl->gl_state, state, flags)) {
1370                 spin_unlock(&gl->gl_spin);
1371                 return;
1372         }
1373
1374         set_bit(GLF_PREFETCH, &gl->gl_flags);
1375         set_bit(GLF_LOCK, &gl->gl_flags);
1376         spin_unlock(&gl->gl_spin);
1377
1378         glops->go_xmote_th(gl, state, flags);
1379 }
1380
1381 static void greedy_work(void *data)
1382 {
1383         struct greedy *gr = data;
1384         struct gfs2_holder *gh = &gr->gr_gh;
1385         struct gfs2_glock *gl = gh->gh_gl;
1386         const struct gfs2_glock_operations *glops = gl->gl_ops;
1387
1388         clear_bit(GLF_SKIP_WAITERS2, &gl->gl_flags);
1389
1390         if (glops->go_greedy)
1391                 glops->go_greedy(gl);
1392
1393         spin_lock(&gl->gl_spin);
1394
1395         if (list_empty(&gl->gl_waiters2)) {
1396                 clear_bit(GLF_GREEDY, &gl->gl_flags);
1397                 spin_unlock(&gl->gl_spin);
1398                 gfs2_holder_uninit(gh);
1399                 kfree(gr);
1400         } else {
1401                 gfs2_glock_hold(gl);
1402                 list_add_tail(&gh->gh_list, &gl->gl_waiters2);
1403                 run_queue(gl);
1404                 spin_unlock(&gl->gl_spin);
1405                 gfs2_glock_put(gl);
1406         }
1407 }
1408
1409 /**
1410  * gfs2_glock_be_greedy -
1411  * @gl:
1412  * @time:
1413  *
1414  * Returns: 0 if go_greedy will be called, 1 otherwise
1415  */
1416
1417 int gfs2_glock_be_greedy(struct gfs2_glock *gl, unsigned int time)
1418 {
1419         struct greedy *gr;
1420         struct gfs2_holder *gh;
1421
1422         if (!time || gl->gl_sbd->sd_args.ar_localcaching ||
1423             test_and_set_bit(GLF_GREEDY, &gl->gl_flags))
1424                 return 1;
1425
1426         gr = kmalloc(sizeof(struct greedy), GFP_KERNEL);
1427         if (!gr) {
1428                 clear_bit(GLF_GREEDY, &gl->gl_flags);
1429                 return 1;
1430         }
1431         gh = &gr->gr_gh;
1432
1433         gfs2_holder_init(gl, 0, 0, gh);
1434         set_bit(HIF_GREEDY, &gh->gh_iflags);
1435         INIT_WORK(&gr->gr_work, greedy_work, gr);
1436
1437         set_bit(GLF_SKIP_WAITERS2, &gl->gl_flags);
1438         schedule_delayed_work(&gr->gr_work, time);
1439
1440         return 0;
1441 }
1442
1443 /**
1444  * gfs2_glock_dq_uninit - dequeue a holder from a glock and initialize it
1445  * @gh: the holder structure
1446  *
1447  */
1448
1449 void gfs2_glock_dq_uninit(struct gfs2_holder *gh)
1450 {
1451         gfs2_glock_dq(gh);
1452         gfs2_holder_uninit(gh);
1453 }
1454
1455 /**
1456  * gfs2_glock_nq_num - acquire a glock based on lock number
1457  * @sdp: the filesystem
1458  * @number: the lock number
1459  * @glops: the glock operations for the type of glock
1460  * @state: the state to acquire the glock in
1461  * @flags: modifier flags for the aquisition
1462  * @gh: the struct gfs2_holder
1463  *
1464  * Returns: errno
1465  */
1466
1467 int gfs2_glock_nq_num(struct gfs2_sbd *sdp, u64 number,
1468                       const struct gfs2_glock_operations *glops,
1469                       unsigned int state, int flags, struct gfs2_holder *gh)
1470 {
1471         struct gfs2_glock *gl;
1472         int error;
1473
1474         error = gfs2_glock_get(sdp, number, glops, CREATE, &gl);
1475         if (!error) {
1476                 error = gfs2_glock_nq_init(gl, state, flags, gh);
1477                 gfs2_glock_put(gl);
1478         }
1479
1480         return error;
1481 }
1482
1483 /**
1484  * glock_compare - Compare two struct gfs2_glock structures for sorting
1485  * @arg_a: the first structure
1486  * @arg_b: the second structure
1487  *
1488  */
1489
1490 static int glock_compare(const void *arg_a, const void *arg_b)
1491 {
1492         const struct gfs2_holder *gh_a = *(const struct gfs2_holder **)arg_a;
1493         const struct gfs2_holder *gh_b = *(const struct gfs2_holder **)arg_b;
1494         const struct lm_lockname *a = &gh_a->gh_gl->gl_name;
1495         const struct lm_lockname *b = &gh_b->gh_gl->gl_name;
1496
1497         if (a->ln_number > b->ln_number)
1498                 return 1;
1499         if (a->ln_number < b->ln_number)
1500                 return -1;
1501         if (gh_a->gh_state == LM_ST_SHARED && gh_b->gh_state == LM_ST_EXCLUSIVE)
1502                 return 1;
1503         if (!(gh_a->gh_flags & GL_LOCAL_EXCL) && (gh_b->gh_flags & GL_LOCAL_EXCL))
1504                 return 1;
1505         return 0;
1506 }
1507
1508 /**
1509  * nq_m_sync - synchonously acquire more than one glock in deadlock free order
1510  * @num_gh: the number of structures
1511  * @ghs: an array of struct gfs2_holder structures
1512  *
1513  * Returns: 0 on success (all glocks acquired),
1514  *          errno on failure (no glocks acquired)
1515  */
1516
1517 static int nq_m_sync(unsigned int num_gh, struct gfs2_holder *ghs,
1518                      struct gfs2_holder **p)
1519 {
1520         unsigned int x;
1521         int error = 0;
1522
1523         for (x = 0; x < num_gh; x++)
1524                 p[x] = &ghs[x];
1525
1526         sort(p, num_gh, sizeof(struct gfs2_holder *), glock_compare, NULL);
1527
1528         for (x = 0; x < num_gh; x++) {
1529                 p[x]->gh_flags &= ~(LM_FLAG_TRY | GL_ASYNC);
1530
1531                 error = gfs2_glock_nq(p[x]);
1532                 if (error) {
1533                         while (x--)
1534                                 gfs2_glock_dq(p[x]);
1535                         break;
1536                 }
1537         }
1538
1539         return error;
1540 }
1541
1542 /**
1543  * gfs2_glock_nq_m - acquire multiple glocks
1544  * @num_gh: the number of structures
1545  * @ghs: an array of struct gfs2_holder structures
1546  *
1547  * Figure out how big an impact this function has.  Either:
1548  * 1) Replace this code with code that calls gfs2_glock_prefetch()
1549  * 2) Forget async stuff and just call nq_m_sync()
1550  * 3) Leave it like it is
1551  *
1552  * Returns: 0 on success (all glocks acquired),
1553  *          errno on failure (no glocks acquired)
1554  */
1555
1556 int gfs2_glock_nq_m(unsigned int num_gh, struct gfs2_holder *ghs)
1557 {
1558         int *e;
1559         unsigned int x;
1560         int borked = 0, serious = 0;
1561         int error = 0;
1562
1563         if (!num_gh)
1564                 return 0;
1565
1566         if (num_gh == 1) {
1567                 ghs->gh_flags &= ~(LM_FLAG_TRY | GL_ASYNC);
1568                 return gfs2_glock_nq(ghs);
1569         }
1570
1571         e = kcalloc(num_gh, sizeof(struct gfs2_holder *), GFP_KERNEL);
1572         if (!e)
1573                 return -ENOMEM;
1574
1575         for (x = 0; x < num_gh; x++) {
1576                 ghs[x].gh_flags |= LM_FLAG_TRY | GL_ASYNC;
1577                 error = gfs2_glock_nq(&ghs[x]);
1578                 if (error) {
1579                         borked = 1;
1580                         serious = error;
1581                         num_gh = x;
1582                         break;
1583                 }
1584         }
1585
1586         for (x = 0; x < num_gh; x++) {
1587                 error = e[x] = glock_wait_internal(&ghs[x]);
1588                 if (error) {
1589                         borked = 1;
1590                         if (error != GLR_TRYFAILED && error != GLR_CANCELED)
1591                                 serious = error;
1592                 }
1593         }
1594
1595         if (!borked) {
1596                 kfree(e);
1597                 return 0;
1598         }
1599
1600         for (x = 0; x < num_gh; x++)
1601                 if (!e[x])
1602                         gfs2_glock_dq(&ghs[x]);
1603
1604         if (serious)
1605                 error = serious;
1606         else {
1607                 for (x = 0; x < num_gh; x++)
1608                         gfs2_holder_reinit(ghs[x].gh_state, ghs[x].gh_flags,
1609                                           &ghs[x]);
1610                 error = nq_m_sync(num_gh, ghs, (struct gfs2_holder **)e);
1611         }
1612
1613         kfree(e);
1614
1615         return error;
1616 }
1617
1618 /**
1619  * gfs2_glock_dq_m - release multiple glocks
1620  * @num_gh: the number of structures
1621  * @ghs: an array of struct gfs2_holder structures
1622  *
1623  */
1624
1625 void gfs2_glock_dq_m(unsigned int num_gh, struct gfs2_holder *ghs)
1626 {
1627         unsigned int x;
1628
1629         for (x = 0; x < num_gh; x++)
1630                 gfs2_glock_dq(&ghs[x]);
1631 }
1632
1633 /**
1634  * gfs2_glock_dq_uninit_m - release multiple glocks
1635  * @num_gh: the number of structures
1636  * @ghs: an array of struct gfs2_holder structures
1637  *
1638  */
1639
1640 void gfs2_glock_dq_uninit_m(unsigned int num_gh, struct gfs2_holder *ghs)
1641 {
1642         unsigned int x;
1643
1644         for (x = 0; x < num_gh; x++)
1645                 gfs2_glock_dq_uninit(&ghs[x]);
1646 }
1647
1648 /**
1649  * gfs2_glock_prefetch_num - prefetch a glock based on lock number
1650  * @sdp: the filesystem
1651  * @number: the lock number
1652  * @glops: the glock operations for the type of glock
1653  * @state: the state to acquire the glock in
1654  * @flags: modifier flags for the aquisition
1655  *
1656  * Returns: errno
1657  */
1658
1659 void gfs2_glock_prefetch_num(struct gfs2_sbd *sdp, u64 number,
1660                              const struct gfs2_glock_operations *glops,
1661                              unsigned int state, int flags)
1662 {
1663         struct gfs2_glock *gl;
1664         int error;
1665
1666         if (atomic_read(&sdp->sd_reclaim_count) <
1667             gfs2_tune_get(sdp, gt_reclaim_limit)) {
1668                 error = gfs2_glock_get(sdp, number, glops, CREATE, &gl);
1669                 if (!error) {
1670                         gfs2_glock_prefetch(gl, state, flags);
1671                         gfs2_glock_put(gl);
1672                 }
1673         }
1674 }
1675
1676 /**
1677  * gfs2_lvb_hold - attach a LVB from a glock
1678  * @gl: The glock in question
1679  *
1680  */
1681
1682 int gfs2_lvb_hold(struct gfs2_glock *gl)
1683 {
1684         int error;
1685
1686         gfs2_glmutex_lock(gl);
1687
1688         if (!atomic_read(&gl->gl_lvb_count)) {
1689                 error = gfs2_lm_hold_lvb(gl->gl_sbd, gl->gl_lock, &gl->gl_lvb);
1690                 if (error) {
1691                         gfs2_glmutex_unlock(gl);
1692                         return error;
1693                 }
1694                 gfs2_glock_hold(gl);
1695         }
1696         atomic_inc(&gl->gl_lvb_count);
1697
1698         gfs2_glmutex_unlock(gl);
1699
1700         return 0;
1701 }
1702
1703 /**
1704  * gfs2_lvb_unhold - detach a LVB from a glock
1705  * @gl: The glock in question
1706  *
1707  */
1708
1709 void gfs2_lvb_unhold(struct gfs2_glock *gl)
1710 {
1711         gfs2_glock_hold(gl);
1712         gfs2_glmutex_lock(gl);
1713
1714         gfs2_assert(gl->gl_sbd, atomic_read(&gl->gl_lvb_count) > 0);
1715         if (atomic_dec_and_test(&gl->gl_lvb_count)) {
1716                 gfs2_lm_unhold_lvb(gl->gl_sbd, gl->gl_lock, gl->gl_lvb);
1717                 gl->gl_lvb = NULL;
1718                 gfs2_glock_put(gl);
1719         }
1720
1721         gfs2_glmutex_unlock(gl);
1722         gfs2_glock_put(gl);
1723 }
1724
1725 static void blocking_cb(struct gfs2_sbd *sdp, struct lm_lockname *name,
1726                         unsigned int state)
1727 {
1728         struct gfs2_glock *gl;
1729
1730         gl = gfs2_glock_find(sdp, name);
1731         if (!gl)
1732                 return;
1733
1734         if (gl->gl_ops->go_callback)
1735                 gl->gl_ops->go_callback(gl, state);
1736         handle_callback(gl, state);
1737
1738         spin_lock(&gl->gl_spin);
1739         run_queue(gl);
1740         spin_unlock(&gl->gl_spin);
1741
1742         gfs2_glock_put(gl);
1743 }
1744
1745 /**
1746  * gfs2_glock_cb - Callback used by locking module
1747  * @sdp: Pointer to the superblock
1748  * @type: Type of callback
1749  * @data: Type dependent data pointer
1750  *
1751  * Called by the locking module when it wants to tell us something.
1752  * Either we need to drop a lock, one of our ASYNC requests completed, or
1753  * a journal from another client needs to be recovered.
1754  */
1755
1756 void gfs2_glock_cb(void *cb_data, unsigned int type, void *data)
1757 {
1758         struct gfs2_sbd *sdp = cb_data;
1759
1760         switch (type) {
1761         case LM_CB_NEED_E:
1762                 blocking_cb(sdp, data, LM_ST_UNLOCKED);
1763                 return;
1764
1765         case LM_CB_NEED_D:
1766                 blocking_cb(sdp, data, LM_ST_DEFERRED);
1767                 return;
1768
1769         case LM_CB_NEED_S:
1770                 blocking_cb(sdp, data, LM_ST_SHARED);
1771                 return;
1772
1773         case LM_CB_ASYNC: {
1774                 struct lm_async_cb *async = data;
1775                 struct gfs2_glock *gl;
1776
1777                 gl = gfs2_glock_find(sdp, &async->lc_name);
1778                 if (gfs2_assert_warn(sdp, gl))
1779                         return;
1780                 if (!gfs2_assert_warn(sdp, gl->gl_req_bh))
1781                         gl->gl_req_bh(gl, async->lc_ret);
1782                 gfs2_glock_put(gl);
1783                 return;
1784         }
1785
1786         case LM_CB_NEED_RECOVERY:
1787                 gfs2_jdesc_make_dirty(sdp, *(unsigned int *)data);
1788                 if (sdp->sd_recoverd_process)
1789                         wake_up_process(sdp->sd_recoverd_process);
1790                 return;
1791
1792         case LM_CB_DROPLOCKS:
1793                 gfs2_gl_hash_clear(sdp, NO_WAIT);
1794                 gfs2_quota_scan(sdp);
1795                 return;
1796
1797         default:
1798                 gfs2_assert_warn(sdp, 0);
1799                 return;
1800         }
1801 }
1802
1803 /**
1804  * demote_ok - Check to see if it's ok to unlock a glock
1805  * @gl: the glock
1806  *
1807  * Returns: 1 if it's ok
1808  */
1809
1810 static int demote_ok(struct gfs2_glock *gl)
1811 {
1812         struct gfs2_sbd *sdp = gl->gl_sbd;
1813         const struct gfs2_glock_operations *glops = gl->gl_ops;
1814         int demote = 1;
1815
1816         if (test_bit(GLF_STICKY, &gl->gl_flags))
1817                 demote = 0;
1818         else if (test_bit(GLF_PREFETCH, &gl->gl_flags))
1819                 demote = time_after_eq(jiffies, gl->gl_stamp +
1820                                     gfs2_tune_get(sdp, gt_prefetch_secs) * HZ);
1821         else if (glops->go_demote_ok)
1822                 demote = glops->go_demote_ok(gl);
1823
1824         return demote;
1825 }
1826
1827 /**
1828  * gfs2_glock_schedule_for_reclaim - Add a glock to the reclaim list
1829  * @gl: the glock
1830  *
1831  */
1832
1833 void gfs2_glock_schedule_for_reclaim(struct gfs2_glock *gl)
1834 {
1835         struct gfs2_sbd *sdp = gl->gl_sbd;
1836
1837         spin_lock(&sdp->sd_reclaim_lock);
1838         if (list_empty(&gl->gl_reclaim)) {
1839                 gfs2_glock_hold(gl);
1840                 list_add(&gl->gl_reclaim, &sdp->sd_reclaim_list);
1841                 atomic_inc(&sdp->sd_reclaim_count);
1842         }
1843         spin_unlock(&sdp->sd_reclaim_lock);
1844
1845         wake_up(&sdp->sd_reclaim_wq);
1846 }
1847
1848 /**
1849  * gfs2_reclaim_glock - process the next glock on the filesystem's reclaim list
1850  * @sdp: the filesystem
1851  *
1852  * Called from gfs2_glockd() glock reclaim daemon, or when promoting a
1853  * different glock and we notice that there are a lot of glocks in the
1854  * reclaim list.
1855  *
1856  */
1857
1858 void gfs2_reclaim_glock(struct gfs2_sbd *sdp)
1859 {
1860         struct gfs2_glock *gl;
1861
1862         spin_lock(&sdp->sd_reclaim_lock);
1863         if (list_empty(&sdp->sd_reclaim_list)) {
1864                 spin_unlock(&sdp->sd_reclaim_lock);
1865                 return;
1866         }
1867         gl = list_entry(sdp->sd_reclaim_list.next,
1868                         struct gfs2_glock, gl_reclaim);
1869         list_del_init(&gl->gl_reclaim);
1870         spin_unlock(&sdp->sd_reclaim_lock);
1871
1872         atomic_dec(&sdp->sd_reclaim_count);
1873         atomic_inc(&sdp->sd_reclaimed);
1874
1875         if (gfs2_glmutex_trylock(gl)) {
1876                 if (queue_empty(gl, &gl->gl_holders) &&
1877                     gl->gl_state != LM_ST_UNLOCKED && demote_ok(gl))
1878                         handle_callback(gl, LM_ST_UNLOCKED);
1879                 gfs2_glmutex_unlock(gl);
1880         }
1881
1882         gfs2_glock_put(gl);
1883 }
1884
1885 /**
1886  * examine_bucket - Call a function for glock in a hash bucket
1887  * @examiner: the function
1888  * @sdp: the filesystem
1889  * @bucket: the bucket
1890  *
1891  * Returns: 1 if the bucket has entries
1892  */
1893
1894 static int examine_bucket(glock_examiner examiner, struct gfs2_sbd *sdp,
1895                           unsigned int hash)
1896 {
1897         struct gfs2_glock *gl, *prev = NULL;
1898         int has_entries = 0;
1899         struct hlist_head *head = &gl_hash_table[hash].hb_list;
1900
1901         read_lock(gl_lock_addr(hash));
1902         /* Can't use hlist_for_each_entry - don't want prefetch here */
1903         if (hlist_empty(head))
1904                 goto out;
1905         has_entries = 1;
1906         gl = list_entry(head->first, struct gfs2_glock, gl_list);
1907         while(1) {
1908                 if (gl->gl_sbd == sdp) {
1909                         gfs2_glock_hold(gl);
1910                         read_unlock(gl_lock_addr(hash));
1911                         if (prev)
1912                                 gfs2_glock_put(prev);
1913                         prev = gl;
1914                         examiner(gl);
1915                         read_lock(gl_lock_addr(hash));
1916                 }
1917                 if (gl->gl_list.next == NULL)
1918                         break;
1919                 gl = list_entry(gl->gl_list.next, struct gfs2_glock, gl_list);
1920         }
1921 out:
1922         read_unlock(gl_lock_addr(hash));
1923         if (prev)
1924                 gfs2_glock_put(prev);
1925         return has_entries;
1926 }
1927
1928 /**
1929  * scan_glock - look at a glock and see if we can reclaim it
1930  * @gl: the glock to look at
1931  *
1932  */
1933
1934 static void scan_glock(struct gfs2_glock *gl)
1935 {
1936         if (gl->gl_ops == &gfs2_inode_glops)
1937                 return;
1938
1939         if (gfs2_glmutex_trylock(gl)) {
1940                 if (queue_empty(gl, &gl->gl_holders) &&
1941                     gl->gl_state != LM_ST_UNLOCKED && demote_ok(gl))
1942                         goto out_schedule;
1943                 gfs2_glmutex_unlock(gl);
1944         }
1945         return;
1946
1947 out_schedule:
1948         gfs2_glmutex_unlock(gl);
1949         gfs2_glock_schedule_for_reclaim(gl);
1950 }
1951
1952 /**
1953  * gfs2_scand_internal - Look for glocks and inodes to toss from memory
1954  * @sdp: the filesystem
1955  *
1956  */
1957
1958 void gfs2_scand_internal(struct gfs2_sbd *sdp)
1959 {
1960         unsigned int x;
1961
1962         for (x = 0; x < GFS2_GL_HASH_SIZE; x++)
1963                 examine_bucket(scan_glock, sdp, x);
1964 }
1965
1966 /**
1967  * clear_glock - look at a glock and see if we can free it from glock cache
1968  * @gl: the glock to look at
1969  *
1970  */
1971
1972 static void clear_glock(struct gfs2_glock *gl)
1973 {
1974         struct gfs2_sbd *sdp = gl->gl_sbd;
1975         int released;
1976
1977         spin_lock(&sdp->sd_reclaim_lock);
1978         if (!list_empty(&gl->gl_reclaim)) {
1979                 list_del_init(&gl->gl_reclaim);
1980                 atomic_dec(&sdp->sd_reclaim_count);
1981                 spin_unlock(&sdp->sd_reclaim_lock);
1982                 released = gfs2_glock_put(gl);
1983                 gfs2_assert(sdp, !released);
1984         } else {
1985                 spin_unlock(&sdp->sd_reclaim_lock);
1986         }
1987
1988         if (gfs2_glmutex_trylock(gl)) {
1989                 if (queue_empty(gl, &gl->gl_holders) &&
1990                     gl->gl_state != LM_ST_UNLOCKED)
1991                         handle_callback(gl, LM_ST_UNLOCKED);
1992                 gfs2_glmutex_unlock(gl);
1993         }
1994 }
1995
1996 /**
1997  * gfs2_gl_hash_clear - Empty out the glock hash table
1998  * @sdp: the filesystem
1999  * @wait: wait until it's all gone
2000  *
2001  * Called when unmounting the filesystem, or when inter-node lock manager
2002  * requests DROPLOCKS because it is running out of capacity.
2003  */
2004
2005 void gfs2_gl_hash_clear(struct gfs2_sbd *sdp, int wait)
2006 {
2007         unsigned long t;
2008         unsigned int x;
2009         int cont;
2010
2011         t = jiffies;
2012
2013         for (;;) {
2014                 cont = 0;
2015                 for (x = 0; x < GFS2_GL_HASH_SIZE; x++) {
2016                         if (examine_bucket(clear_glock, sdp, x))
2017                                 cont = 1;
2018                 }
2019
2020                 if (!wait || !cont)
2021                         break;
2022
2023                 if (time_after_eq(jiffies,
2024                                   t + gfs2_tune_get(sdp, gt_stall_secs) * HZ)) {
2025                         fs_warn(sdp, "Unmount seems to be stalled. "
2026                                      "Dumping lock state...\n");
2027                         gfs2_dump_lockstate(sdp);
2028                         t = jiffies;
2029                 }
2030
2031                 invalidate_inodes(sdp->sd_vfs);
2032                 msleep(10);
2033         }
2034 }
2035
2036 /*
2037  *  Diagnostic routines to help debug distributed deadlock
2038  */
2039
2040 /**
2041  * dump_holder - print information about a glock holder
2042  * @str: a string naming the type of holder
2043  * @gh: the glock holder
2044  *
2045  * Returns: 0 on success, -ENOBUFS when we run out of space
2046  */
2047
2048 static int dump_holder(char *str, struct gfs2_holder *gh)
2049 {
2050         unsigned int x;
2051         int error = -ENOBUFS;
2052
2053         printk(KERN_INFO "  %s\n", str);
2054         printk(KERN_INFO "    owner = %ld\n",
2055                    (gh->gh_owner) ? (long)gh->gh_owner->pid : -1);
2056         printk(KERN_INFO "    gh_state = %u\n", gh->gh_state);
2057         printk(KERN_INFO "    gh_flags =");
2058         for (x = 0; x < 32; x++)
2059                 if (gh->gh_flags & (1 << x))
2060                         printk(" %u", x);
2061         printk(" \n");
2062         printk(KERN_INFO "    error = %d\n", gh->gh_error);
2063         printk(KERN_INFO "    gh_iflags =");
2064         for (x = 0; x < 32; x++)
2065                 if (test_bit(x, &gh->gh_iflags))
2066                         printk(" %u", x);
2067         printk(" \n");
2068         print_symbol(KERN_INFO "    initialized at: %s\n", gh->gh_ip);
2069
2070         error = 0;
2071
2072         return error;
2073 }
2074
2075 /**
2076  * dump_inode - print information about an inode
2077  * @ip: the inode
2078  *
2079  * Returns: 0 on success, -ENOBUFS when we run out of space
2080  */
2081
2082 static int dump_inode(struct gfs2_inode *ip)
2083 {
2084         unsigned int x;
2085         int error = -ENOBUFS;
2086
2087         printk(KERN_INFO "  Inode:\n");
2088         printk(KERN_INFO "    num = %llu %llu\n",
2089                     (unsigned long long)ip->i_num.no_formal_ino,
2090                     (unsigned long long)ip->i_num.no_addr);
2091         printk(KERN_INFO "    type = %u\n", IF2DT(ip->i_di.di_mode));
2092         printk(KERN_INFO "    i_flags =");
2093         for (x = 0; x < 32; x++)
2094                 if (test_bit(x, &ip->i_flags))
2095                         printk(" %u", x);
2096         printk(" \n");
2097
2098         error = 0;
2099
2100         return error;
2101 }
2102
2103 /**
2104  * dump_glock - print information about a glock
2105  * @gl: the glock
2106  * @count: where we are in the buffer
2107  *
2108  * Returns: 0 on success, -ENOBUFS when we run out of space
2109  */
2110
2111 static int dump_glock(struct gfs2_glock *gl)
2112 {
2113         struct gfs2_holder *gh;
2114         unsigned int x;
2115         int error = -ENOBUFS;
2116
2117         spin_lock(&gl->gl_spin);
2118
2119         printk(KERN_INFO "Glock 0x%p (%u, %llu)\n", gl, gl->gl_name.ln_type,
2120                (unsigned long long)gl->gl_name.ln_number);
2121         printk(KERN_INFO "  gl_flags =");
2122         for (x = 0; x < 32; x++) {
2123                 if (test_bit(x, &gl->gl_flags))
2124                         printk(" %u", x);
2125         }
2126         printk(" \n");
2127         printk(KERN_INFO "  gl_ref = %d\n", atomic_read(&gl->gl_ref.refcount));
2128         printk(KERN_INFO "  gl_state = %u\n", gl->gl_state);
2129         printk(KERN_INFO "  gl_owner = %s\n", gl->gl_owner->comm);
2130         print_symbol(KERN_INFO "  gl_ip = %s\n", gl->gl_ip);
2131         printk(KERN_INFO "  req_gh = %s\n", (gl->gl_req_gh) ? "yes" : "no");
2132         printk(KERN_INFO "  req_bh = %s\n", (gl->gl_req_bh) ? "yes" : "no");
2133         printk(KERN_INFO "  lvb_count = %d\n", atomic_read(&gl->gl_lvb_count));
2134         printk(KERN_INFO "  object = %s\n", (gl->gl_object) ? "yes" : "no");
2135         printk(KERN_INFO "  le = %s\n",
2136                    (list_empty(&gl->gl_le.le_list)) ? "no" : "yes");
2137         printk(KERN_INFO "  reclaim = %s\n",
2138                     (list_empty(&gl->gl_reclaim)) ? "no" : "yes");
2139         if (gl->gl_aspace)
2140                 printk(KERN_INFO "  aspace = 0x%p nrpages = %lu\n", gl->gl_aspace,
2141                        gl->gl_aspace->i_mapping->nrpages);
2142         else
2143                 printk(KERN_INFO "  aspace = no\n");
2144         printk(KERN_INFO "  ail = %d\n", atomic_read(&gl->gl_ail_count));
2145         if (gl->gl_req_gh) {
2146                 error = dump_holder("Request", gl->gl_req_gh);
2147                 if (error)
2148                         goto out;
2149         }
2150         list_for_each_entry(gh, &gl->gl_holders, gh_list) {
2151                 error = dump_holder("Holder", gh);
2152                 if (error)
2153                         goto out;
2154         }
2155         list_for_each_entry(gh, &gl->gl_waiters1, gh_list) {
2156                 error = dump_holder("Waiter1", gh);
2157                 if (error)
2158                         goto out;
2159         }
2160         list_for_each_entry(gh, &gl->gl_waiters2, gh_list) {
2161                 error = dump_holder("Waiter2", gh);
2162                 if (error)
2163                         goto out;
2164         }
2165         list_for_each_entry(gh, &gl->gl_waiters3, gh_list) {
2166                 error = dump_holder("Waiter3", gh);
2167                 if (error)
2168                         goto out;
2169         }
2170         if (gl->gl_ops == &gfs2_inode_glops && gl->gl_object) {
2171                 if (!test_bit(GLF_LOCK, &gl->gl_flags) &&
2172                     list_empty(&gl->gl_holders)) {
2173                         error = dump_inode(gl->gl_object);
2174                         if (error)
2175                                 goto out;
2176                 } else {
2177                         error = -ENOBUFS;
2178                         printk(KERN_INFO "  Inode: busy\n");
2179                 }
2180         }
2181
2182         error = 0;
2183
2184 out:
2185         spin_unlock(&gl->gl_spin);
2186         return error;
2187 }
2188
2189 /**
2190  * gfs2_dump_lockstate - print out the current lockstate
2191  * @sdp: the filesystem
2192  * @ub: the buffer to copy the information into
2193  *
2194  * If @ub is NULL, dump the lockstate to the console.
2195  *
2196  */
2197
2198 static int gfs2_dump_lockstate(struct gfs2_sbd *sdp)
2199 {
2200         struct gfs2_glock *gl;
2201         struct hlist_node *h;
2202         unsigned int x;
2203         int error = 0;
2204
2205         for (x = 0; x < GFS2_GL_HASH_SIZE; x++) {
2206
2207                 read_lock(gl_lock_addr(x));
2208
2209                 hlist_for_each_entry(gl, h, &gl_hash_table[x].hb_list, gl_list) {
2210                         if (gl->gl_sbd != sdp)
2211                                 continue;
2212
2213                         error = dump_glock(gl);
2214                         if (error)
2215                                 break;
2216                 }
2217
2218                 read_unlock(gl_lock_addr(x));
2219
2220                 if (error)
2221                         break;
2222         }
2223
2224
2225         return error;
2226 }
2227
2228 int __init gfs2_glock_init(void)
2229 {
2230         unsigned i;
2231         for(i = 0; i < GFS2_GL_HASH_SIZE; i++) {
2232                 INIT_HLIST_HEAD(&gl_hash_table[i].hb_list);
2233         }
2234 #ifdef GL_HASH_LOCK_SZ
2235         for(i = 0; i < GL_HASH_LOCK_SZ; i++) {
2236                 rwlock_init(&gl_hash_locks[i]);
2237         }
2238 #endif
2239         return 0;
2240 }
2241