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TOMOYO Linux Cross Reference
Linux/fs/gfs2/glock.c

Version: ~ [ linux-4.20-rc2 ] ~ [ linux-4.19.1 ] ~ [ linux-4.18.18 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.80 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.136 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.163 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.125 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.60 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-3.9.11 ] ~ [ linux-3.8.13 ] ~ [ linux-3.7.10 ] ~ [ linux-3.6.11 ] ~ [ linux-3.5.7 ] ~ [ linux-3.4.113 ] ~ [ linux-3.3.8 ] ~ [ linux-3.2.102 ] ~ [ linux-3.1.10 ] ~ [ linux-3.0.101 ] ~ [ linux-2.6.39.4 ] ~ [ linux-2.6.38.8 ] ~ [ linux-2.6.37.6 ] ~ [ linux-2.6.36.4 ] ~ [ linux-2.6.35.14 ] ~ [ linux-2.6.34.15 ] ~ [ linux-2.6.33.20 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.31.14 ] ~ [ linux-2.6.30.10 ] ~ [ linux-2.6.29.6 ] ~ [ linux-2.6.28.10 ] ~ [ linux-2.6.27.62 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
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  1 /*
  2  * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
  3  * Copyright (C) 2004-2008 Red Hat, Inc.  All rights reserved.
  4  *
  5  * This copyrighted material is made available to anyone wishing to use,
  6  * modify, copy, or redistribute it subject to the terms and conditions
  7  * of the GNU General Public License version 2.
  8  */
  9 
 10 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 11 
 12 #include <linux/sched.h>
 13 #include <linux/slab.h>
 14 #include <linux/spinlock.h>
 15 #include <linux/buffer_head.h>
 16 #include <linux/delay.h>
 17 #include <linux/sort.h>
 18 #include <linux/hash.h>
 19 #include <linux/jhash.h>
 20 #include <linux/kallsyms.h>
 21 #include <linux/gfs2_ondisk.h>
 22 #include <linux/list.h>
 23 #include <linux/wait.h>
 24 #include <linux/module.h>
 25 #include <linux/uaccess.h>
 26 #include <linux/seq_file.h>
 27 #include <linux/debugfs.h>
 28 #include <linux/kthread.h>
 29 #include <linux/freezer.h>
 30 #include <linux/workqueue.h>
 31 #include <linux/jiffies.h>
 32 #include <linux/rcupdate.h>
 33 #include <linux/rculist_bl.h>
 34 #include <linux/bit_spinlock.h>
 35 #include <linux/percpu.h>
 36 #include <linux/list_sort.h>
 37 #include <linux/lockref.h>
 38 #include <linux/rhashtable.h>
 39 
 40 #include "gfs2.h"
 41 #include "incore.h"
 42 #include "glock.h"
 43 #include "glops.h"
 44 #include "inode.h"
 45 #include "lops.h"
 46 #include "meta_io.h"
 47 #include "quota.h"
 48 #include "super.h"
 49 #include "util.h"
 50 #include "bmap.h"
 51 #define CREATE_TRACE_POINTS
 52 #include "trace_gfs2.h"
 53 
 54 struct gfs2_glock_iter {
 55         struct gfs2_sbd *sdp;           /* incore superblock           */
 56         struct rhashtable_iter hti;     /* rhashtable iterator         */
 57         struct gfs2_glock *gl;          /* current glock struct        */
 58         loff_t last_pos;                /* last position               */
 59 };
 60 
 61 typedef void (*glock_examiner) (struct gfs2_glock * gl);
 62 
 63 static void do_xmote(struct gfs2_glock *gl, struct gfs2_holder *gh, unsigned int target);
 64 
 65 static struct dentry *gfs2_root;
 66 static struct workqueue_struct *glock_workqueue;
 67 struct workqueue_struct *gfs2_delete_workqueue;
 68 static LIST_HEAD(lru_list);
 69 static atomic_t lru_count = ATOMIC_INIT(0);
 70 static DEFINE_SPINLOCK(lru_lock);
 71 
 72 #define GFS2_GL_HASH_SHIFT      15
 73 #define GFS2_GL_HASH_SIZE       BIT(GFS2_GL_HASH_SHIFT)
 74 
 75 static const struct rhashtable_params ht_parms = {
 76         .nelem_hint = GFS2_GL_HASH_SIZE * 3 / 4,
 77         .key_len = offsetofend(struct lm_lockname, ln_type),
 78         .key_offset = offsetof(struct gfs2_glock, gl_name),
 79         .head_offset = offsetof(struct gfs2_glock, gl_node),
 80 };
 81 
 82 static struct rhashtable gl_hash_table;
 83 
 84 #define GLOCK_WAIT_TABLE_BITS 12
 85 #define GLOCK_WAIT_TABLE_SIZE (1 << GLOCK_WAIT_TABLE_BITS)
 86 static wait_queue_head_t glock_wait_table[GLOCK_WAIT_TABLE_SIZE] __cacheline_aligned;
 87 
 88 struct wait_glock_queue {
 89         struct lm_lockname *name;
 90         wait_queue_entry_t wait;
 91 };
 92 
 93 static int glock_wake_function(wait_queue_entry_t *wait, unsigned int mode,
 94                                int sync, void *key)
 95 {
 96         struct wait_glock_queue *wait_glock =
 97                 container_of(wait, struct wait_glock_queue, wait);
 98         struct lm_lockname *wait_name = wait_glock->name;
 99         struct lm_lockname *wake_name = key;
100 
101         if (wake_name->ln_sbd != wait_name->ln_sbd ||
102             wake_name->ln_number != wait_name->ln_number ||
103             wake_name->ln_type != wait_name->ln_type)
104                 return 0;
105         return autoremove_wake_function(wait, mode, sync, key);
106 }
107 
108 static wait_queue_head_t *glock_waitqueue(struct lm_lockname *name)
109 {
110         u32 hash = jhash2((u32 *)name, sizeof(*name) / 4, 0);
111 
112         return glock_wait_table + hash_32(hash, GLOCK_WAIT_TABLE_BITS);
113 }
114 
115 /**
116  * wake_up_glock  -  Wake up waiters on a glock
117  * @gl: the glock
118  */
119 static void wake_up_glock(struct gfs2_glock *gl)
120 {
121         wait_queue_head_t *wq = glock_waitqueue(&gl->gl_name);
122 
123         if (waitqueue_active(wq))
124                 __wake_up(wq, TASK_NORMAL, 1, &gl->gl_name);
125 }
126 
127 static void gfs2_glock_dealloc(struct rcu_head *rcu)
128 {
129         struct gfs2_glock *gl = container_of(rcu, struct gfs2_glock, gl_rcu);
130 
131         if (gl->gl_ops->go_flags & GLOF_ASPACE) {
132                 kmem_cache_free(gfs2_glock_aspace_cachep, gl);
133         } else {
134                 kfree(gl->gl_lksb.sb_lvbptr);
135                 kmem_cache_free(gfs2_glock_cachep, gl);
136         }
137 }
138 
139 void gfs2_glock_free(struct gfs2_glock *gl)
140 {
141         struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
142 
143         rhashtable_remove_fast(&gl_hash_table, &gl->gl_node, ht_parms);
144         smp_mb();
145         wake_up_glock(gl);
146         call_rcu(&gl->gl_rcu, gfs2_glock_dealloc);
147         if (atomic_dec_and_test(&sdp->sd_glock_disposal))
148                 wake_up(&sdp->sd_glock_wait);
149 }
150 
151 /**
152  * gfs2_glock_hold() - increment reference count on glock
153  * @gl: The glock to hold
154  *
155  */
156 
157 void gfs2_glock_hold(struct gfs2_glock *gl)
158 {
159         GLOCK_BUG_ON(gl, __lockref_is_dead(&gl->gl_lockref));
160         lockref_get(&gl->gl_lockref);
161 }
162 
163 /**
164  * demote_ok - Check to see if it's ok to unlock a glock
165  * @gl: the glock
166  *
167  * Returns: 1 if it's ok
168  */
169 
170 static int demote_ok(const struct gfs2_glock *gl)
171 {
172         const struct gfs2_glock_operations *glops = gl->gl_ops;
173 
174         if (gl->gl_state == LM_ST_UNLOCKED)
175                 return 0;
176         if (!list_empty(&gl->gl_holders))
177                 return 0;
178         if (glops->go_demote_ok)
179                 return glops->go_demote_ok(gl);
180         return 1;
181 }
182 
183 
184 void gfs2_glock_add_to_lru(struct gfs2_glock *gl)
185 {
186         spin_lock(&lru_lock);
187 
188         if (!list_empty(&gl->gl_lru))
189                 list_del_init(&gl->gl_lru);
190         else
191                 atomic_inc(&lru_count);
192 
193         list_add_tail(&gl->gl_lru, &lru_list);
194         set_bit(GLF_LRU, &gl->gl_flags);
195         spin_unlock(&lru_lock);
196 }
197 
198 static void gfs2_glock_remove_from_lru(struct gfs2_glock *gl)
199 {
200         if (!(gl->gl_ops->go_flags & GLOF_LRU))
201                 return;
202 
203         spin_lock(&lru_lock);
204         if (!list_empty(&gl->gl_lru)) {
205                 list_del_init(&gl->gl_lru);
206                 atomic_dec(&lru_count);
207                 clear_bit(GLF_LRU, &gl->gl_flags);
208         }
209         spin_unlock(&lru_lock);
210 }
211 
212 /*
213  * Enqueue the glock on the work queue.  Passes one glock reference on to the
214  * work queue.
215  */
216 static void __gfs2_glock_queue_work(struct gfs2_glock *gl, unsigned long delay) {
217         if (!queue_delayed_work(glock_workqueue, &gl->gl_work, delay)) {
218                 /*
219                  * We are holding the lockref spinlock, and the work was still
220                  * queued above.  The queued work (glock_work_func) takes that
221                  * spinlock before dropping its glock reference(s), so it
222                  * cannot have dropped them in the meantime.
223                  */
224                 GLOCK_BUG_ON(gl, gl->gl_lockref.count < 2);
225                 gl->gl_lockref.count--;
226         }
227 }
228 
229 static void gfs2_glock_queue_work(struct gfs2_glock *gl, unsigned long delay) {
230         spin_lock(&gl->gl_lockref.lock);
231         __gfs2_glock_queue_work(gl, delay);
232         spin_unlock(&gl->gl_lockref.lock);
233 }
234 
235 static void __gfs2_glock_put(struct gfs2_glock *gl)
236 {
237         struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
238         struct address_space *mapping = gfs2_glock2aspace(gl);
239 
240         lockref_mark_dead(&gl->gl_lockref);
241 
242         gfs2_glock_remove_from_lru(gl);
243         spin_unlock(&gl->gl_lockref.lock);
244         GLOCK_BUG_ON(gl, !list_empty(&gl->gl_holders));
245         GLOCK_BUG_ON(gl, mapping && mapping->nrpages);
246         trace_gfs2_glock_put(gl);
247         sdp->sd_lockstruct.ls_ops->lm_put_lock(gl);
248 }
249 
250 /*
251  * Cause the glock to be put in work queue context.
252  */
253 void gfs2_glock_queue_put(struct gfs2_glock *gl)
254 {
255         gfs2_glock_queue_work(gl, 0);
256 }
257 
258 /**
259  * gfs2_glock_put() - Decrement reference count on glock
260  * @gl: The glock to put
261  *
262  */
263 
264 void gfs2_glock_put(struct gfs2_glock *gl)
265 {
266         if (lockref_put_or_lock(&gl->gl_lockref))
267                 return;
268 
269         __gfs2_glock_put(gl);
270 }
271 
272 /**
273  * may_grant - check if its ok to grant a new lock
274  * @gl: The glock
275  * @gh: The lock request which we wish to grant
276  *
277  * Returns: true if its ok to grant the lock
278  */
279 
280 static inline int may_grant(const struct gfs2_glock *gl, const struct gfs2_holder *gh)
281 {
282         const struct gfs2_holder *gh_head = list_entry(gl->gl_holders.next, const struct gfs2_holder, gh_list);
283         if ((gh->gh_state == LM_ST_EXCLUSIVE ||
284              gh_head->gh_state == LM_ST_EXCLUSIVE) && gh != gh_head)
285                 return 0;
286         if (gl->gl_state == gh->gh_state)
287                 return 1;
288         if (gh->gh_flags & GL_EXACT)
289                 return 0;
290         if (gl->gl_state == LM_ST_EXCLUSIVE) {
291                 if (gh->gh_state == LM_ST_SHARED && gh_head->gh_state == LM_ST_SHARED)
292                         return 1;
293                 if (gh->gh_state == LM_ST_DEFERRED && gh_head->gh_state == LM_ST_DEFERRED)
294                         return 1;
295         }
296         if (gl->gl_state != LM_ST_UNLOCKED && (gh->gh_flags & LM_FLAG_ANY))
297                 return 1;
298         return 0;
299 }
300 
301 static void gfs2_holder_wake(struct gfs2_holder *gh)
302 {
303         clear_bit(HIF_WAIT, &gh->gh_iflags);
304         smp_mb__after_atomic();
305         wake_up_bit(&gh->gh_iflags, HIF_WAIT);
306 }
307 
308 /**
309  * do_error - Something unexpected has happened during a lock request
310  *
311  */
312 
313 static void do_error(struct gfs2_glock *gl, const int ret)
314 {
315         struct gfs2_holder *gh, *tmp;
316 
317         list_for_each_entry_safe(gh, tmp, &gl->gl_holders, gh_list) {
318                 if (test_bit(HIF_HOLDER, &gh->gh_iflags))
319                         continue;
320                 if (ret & LM_OUT_ERROR)
321                         gh->gh_error = -EIO;
322                 else if (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB))
323                         gh->gh_error = GLR_TRYFAILED;
324                 else
325                         continue;
326                 list_del_init(&gh->gh_list);
327                 trace_gfs2_glock_queue(gh, 0);
328                 gfs2_holder_wake(gh);
329         }
330 }
331 
332 /**
333  * do_promote - promote as many requests as possible on the current queue
334  * @gl: The glock
335  * 
336  * Returns: 1 if there is a blocked holder at the head of the list, or 2
337  *          if a type specific operation is underway.
338  */
339 
340 static int do_promote(struct gfs2_glock *gl)
341 __releases(&gl->gl_lockref.lock)
342 __acquires(&gl->gl_lockref.lock)
343 {
344         const struct gfs2_glock_operations *glops = gl->gl_ops;
345         struct gfs2_holder *gh, *tmp;
346         int ret;
347 
348 restart:
349         list_for_each_entry_safe(gh, tmp, &gl->gl_holders, gh_list) {
350                 if (test_bit(HIF_HOLDER, &gh->gh_iflags))
351                         continue;
352                 if (may_grant(gl, gh)) {
353                         if (gh->gh_list.prev == &gl->gl_holders &&
354                             glops->go_lock) {
355                                 spin_unlock(&gl->gl_lockref.lock);
356                                 /* FIXME: eliminate this eventually */
357                                 ret = glops->go_lock(gh);
358                                 spin_lock(&gl->gl_lockref.lock);
359                                 if (ret) {
360                                         if (ret == 1)
361                                                 return 2;
362                                         gh->gh_error = ret;
363                                         list_del_init(&gh->gh_list);
364                                         trace_gfs2_glock_queue(gh, 0);
365                                         gfs2_holder_wake(gh);
366                                         goto restart;
367                                 }
368                                 set_bit(HIF_HOLDER, &gh->gh_iflags);
369                                 trace_gfs2_promote(gh, 1);
370                                 gfs2_holder_wake(gh);
371                                 goto restart;
372                         }
373                         set_bit(HIF_HOLDER, &gh->gh_iflags);
374                         trace_gfs2_promote(gh, 0);
375                         gfs2_holder_wake(gh);
376                         continue;
377                 }
378                 if (gh->gh_list.prev == &gl->gl_holders)
379                         return 1;
380                 do_error(gl, 0);
381                 break;
382         }
383         return 0;
384 }
385 
386 /**
387  * find_first_waiter - find the first gh that's waiting for the glock
388  * @gl: the glock
389  */
390 
391 static inline struct gfs2_holder *find_first_waiter(const struct gfs2_glock *gl)
392 {
393         struct gfs2_holder *gh;
394 
395         list_for_each_entry(gh, &gl->gl_holders, gh_list) {
396                 if (!test_bit(HIF_HOLDER, &gh->gh_iflags))
397                         return gh;
398         }
399         return NULL;
400 }
401 
402 /**
403  * state_change - record that the glock is now in a different state
404  * @gl: the glock
405  * @new_state the new state
406  *
407  */
408 
409 static void state_change(struct gfs2_glock *gl, unsigned int new_state)
410 {
411         int held1, held2;
412 
413         held1 = (gl->gl_state != LM_ST_UNLOCKED);
414         held2 = (new_state != LM_ST_UNLOCKED);
415 
416         if (held1 != held2) {
417                 GLOCK_BUG_ON(gl, __lockref_is_dead(&gl->gl_lockref));
418                 if (held2)
419                         gl->gl_lockref.count++;
420                 else
421                         gl->gl_lockref.count--;
422         }
423         if (held1 && held2 && list_empty(&gl->gl_holders))
424                 clear_bit(GLF_QUEUED, &gl->gl_flags);
425 
426         if (new_state != gl->gl_target)
427                 /* shorten our minimum hold time */
428                 gl->gl_hold_time = max(gl->gl_hold_time - GL_GLOCK_HOLD_DECR,
429                                        GL_GLOCK_MIN_HOLD);
430         gl->gl_state = new_state;
431         gl->gl_tchange = jiffies;
432 }
433 
434 static void gfs2_demote_wake(struct gfs2_glock *gl)
435 {
436         gl->gl_demote_state = LM_ST_EXCLUSIVE;
437         clear_bit(GLF_DEMOTE, &gl->gl_flags);
438         smp_mb__after_atomic();
439         wake_up_bit(&gl->gl_flags, GLF_DEMOTE);
440 }
441 
442 /**
443  * finish_xmote - The DLM has replied to one of our lock requests
444  * @gl: The glock
445  * @ret: The status from the DLM
446  *
447  */
448 
449 static void finish_xmote(struct gfs2_glock *gl, unsigned int ret)
450 {
451         const struct gfs2_glock_operations *glops = gl->gl_ops;
452         struct gfs2_holder *gh;
453         unsigned state = ret & LM_OUT_ST_MASK;
454         int rv;
455 
456         spin_lock(&gl->gl_lockref.lock);
457         trace_gfs2_glock_state_change(gl, state);
458         state_change(gl, state);
459         gh = find_first_waiter(gl);
460 
461         /* Demote to UN request arrived during demote to SH or DF */
462         if (test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags) &&
463             state != LM_ST_UNLOCKED && gl->gl_demote_state == LM_ST_UNLOCKED)
464                 gl->gl_target = LM_ST_UNLOCKED;
465 
466         /* Check for state != intended state */
467         if (unlikely(state != gl->gl_target)) {
468                 if (gh && !test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags)) {
469                         /* move to back of queue and try next entry */
470                         if (ret & LM_OUT_CANCELED) {
471                                 if ((gh->gh_flags & LM_FLAG_PRIORITY) == 0)
472                                         list_move_tail(&gh->gh_list, &gl->gl_holders);
473                                 gh = find_first_waiter(gl);
474                                 gl->gl_target = gh->gh_state;
475                                 goto retry;
476                         }
477                         /* Some error or failed "try lock" - report it */
478                         if ((ret & LM_OUT_ERROR) ||
479                             (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB))) {
480                                 gl->gl_target = gl->gl_state;
481                                 do_error(gl, ret);
482                                 goto out;
483                         }
484                 }
485                 switch(state) {
486                 /* Unlocked due to conversion deadlock, try again */
487                 case LM_ST_UNLOCKED:
488 retry:
489                         do_xmote(gl, gh, gl->gl_target);
490                         break;
491                 /* Conversion fails, unlock and try again */
492                 case LM_ST_SHARED:
493                 case LM_ST_DEFERRED:
494                         do_xmote(gl, gh, LM_ST_UNLOCKED);
495                         break;
496                 default: /* Everything else */
497                         fs_err(gl->gl_name.ln_sbd, "wanted %u got %u\n",
498                                gl->gl_target, state);
499                         GLOCK_BUG_ON(gl, 1);
500                 }
501                 spin_unlock(&gl->gl_lockref.lock);
502                 return;
503         }
504 
505         /* Fast path - we got what we asked for */
506         if (test_and_clear_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags))
507                 gfs2_demote_wake(gl);
508         if (state != LM_ST_UNLOCKED) {
509                 if (glops->go_xmote_bh) {
510                         spin_unlock(&gl->gl_lockref.lock);
511                         rv = glops->go_xmote_bh(gl, gh);
512                         spin_lock(&gl->gl_lockref.lock);
513                         if (rv) {
514                                 do_error(gl, rv);
515                                 goto out;
516                         }
517                 }
518                 rv = do_promote(gl);
519                 if (rv == 2)
520                         goto out_locked;
521         }
522 out:
523         clear_bit(GLF_LOCK, &gl->gl_flags);
524 out_locked:
525         spin_unlock(&gl->gl_lockref.lock);
526 }
527 
528 /**
529  * do_xmote - Calls the DLM to change the state of a lock
530  * @gl: The lock state
531  * @gh: The holder (only for promotes)
532  * @target: The target lock state
533  *
534  */
535 
536 static void do_xmote(struct gfs2_glock *gl, struct gfs2_holder *gh, unsigned int target)
537 __releases(&gl->gl_lockref.lock)
538 __acquires(&gl->gl_lockref.lock)
539 {
540         const struct gfs2_glock_operations *glops = gl->gl_ops;
541         struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
542         unsigned int lck_flags = (unsigned int)(gh ? gh->gh_flags : 0);
543         int ret;
544 
545         if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)) &&
546             target != LM_ST_UNLOCKED)
547                 return;
548         lck_flags &= (LM_FLAG_TRY | LM_FLAG_TRY_1CB | LM_FLAG_NOEXP |
549                       LM_FLAG_PRIORITY);
550         GLOCK_BUG_ON(gl, gl->gl_state == target);
551         GLOCK_BUG_ON(gl, gl->gl_state == gl->gl_target);
552         if ((target == LM_ST_UNLOCKED || target == LM_ST_DEFERRED) &&
553             glops->go_inval) {
554                 set_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags);
555                 do_error(gl, 0); /* Fail queued try locks */
556         }
557         gl->gl_req = target;
558         set_bit(GLF_BLOCKING, &gl->gl_flags);
559         if ((gl->gl_req == LM_ST_UNLOCKED) ||
560             (gl->gl_state == LM_ST_EXCLUSIVE) ||
561             (lck_flags & (LM_FLAG_TRY|LM_FLAG_TRY_1CB)))
562                 clear_bit(GLF_BLOCKING, &gl->gl_flags);
563         spin_unlock(&gl->gl_lockref.lock);
564         if (glops->go_sync)
565                 glops->go_sync(gl);
566         if (test_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags))
567                 glops->go_inval(gl, target == LM_ST_DEFERRED ? 0 : DIO_METADATA);
568         clear_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags);
569 
570         gfs2_glock_hold(gl);
571         if (sdp->sd_lockstruct.ls_ops->lm_lock) {
572                 /* lock_dlm */
573                 ret = sdp->sd_lockstruct.ls_ops->lm_lock(gl, target, lck_flags);
574                 if (ret == -EINVAL && gl->gl_target == LM_ST_UNLOCKED &&
575                     target == LM_ST_UNLOCKED &&
576                     test_bit(SDF_SKIP_DLM_UNLOCK, &sdp->sd_flags)) {
577                         finish_xmote(gl, target);
578                         gfs2_glock_queue_work(gl, 0);
579                 }
580                 else if (ret) {
581                         fs_err(sdp, "lm_lock ret %d\n", ret);
582                         GLOCK_BUG_ON(gl, !test_bit(SDF_SHUTDOWN,
583                                                    &sdp->sd_flags));
584                 }
585         } else { /* lock_nolock */
586                 finish_xmote(gl, target);
587                 gfs2_glock_queue_work(gl, 0);
588         }
589 
590         spin_lock(&gl->gl_lockref.lock);
591 }
592 
593 /**
594  * find_first_holder - find the first "holder" gh
595  * @gl: the glock
596  */
597 
598 static inline struct gfs2_holder *find_first_holder(const struct gfs2_glock *gl)
599 {
600         struct gfs2_holder *gh;
601 
602         if (!list_empty(&gl->gl_holders)) {
603                 gh = list_entry(gl->gl_holders.next, struct gfs2_holder, gh_list);
604                 if (test_bit(HIF_HOLDER, &gh->gh_iflags))
605                         return gh;
606         }
607         return NULL;
608 }
609 
610 /**
611  * run_queue - do all outstanding tasks related to a glock
612  * @gl: The glock in question
613  * @nonblock: True if we must not block in run_queue
614  *
615  */
616 
617 static void run_queue(struct gfs2_glock *gl, const int nonblock)
618 __releases(&gl->gl_lockref.lock)
619 __acquires(&gl->gl_lockref.lock)
620 {
621         struct gfs2_holder *gh = NULL;
622         int ret;
623 
624         if (test_and_set_bit(GLF_LOCK, &gl->gl_flags))
625                 return;
626 
627         GLOCK_BUG_ON(gl, test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags));
628 
629         if (test_bit(GLF_DEMOTE, &gl->gl_flags) &&
630             gl->gl_demote_state != gl->gl_state) {
631                 if (find_first_holder(gl))
632                         goto out_unlock;
633                 if (nonblock)
634                         goto out_sched;
635                 set_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags);
636                 GLOCK_BUG_ON(gl, gl->gl_demote_state == LM_ST_EXCLUSIVE);
637                 gl->gl_target = gl->gl_demote_state;
638         } else {
639                 if (test_bit(GLF_DEMOTE, &gl->gl_flags))
640                         gfs2_demote_wake(gl);
641                 ret = do_promote(gl);
642                 if (ret == 0)
643                         goto out_unlock;
644                 if (ret == 2)
645                         goto out;
646                 gh = find_first_waiter(gl);
647                 gl->gl_target = gh->gh_state;
648                 if (!(gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)))
649                         do_error(gl, 0); /* Fail queued try locks */
650         }
651         do_xmote(gl, gh, gl->gl_target);
652 out:
653         return;
654 
655 out_sched:
656         clear_bit(GLF_LOCK, &gl->gl_flags);
657         smp_mb__after_atomic();
658         gl->gl_lockref.count++;
659         __gfs2_glock_queue_work(gl, 0);
660         return;
661 
662 out_unlock:
663         clear_bit(GLF_LOCK, &gl->gl_flags);
664         smp_mb__after_atomic();
665         return;
666 }
667 
668 static void delete_work_func(struct work_struct *work)
669 {
670         struct gfs2_glock *gl = container_of(work, struct gfs2_glock, gl_delete);
671         struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
672         struct inode *inode;
673         u64 no_addr = gl->gl_name.ln_number;
674 
675         /* If someone's using this glock to create a new dinode, the block must
676            have been freed by another node, then re-used, in which case our
677            iopen callback is too late after the fact. Ignore it. */
678         if (test_bit(GLF_INODE_CREATING, &gl->gl_flags))
679                 goto out;
680 
681         inode = gfs2_lookup_by_inum(sdp, no_addr, NULL, GFS2_BLKST_UNLINKED);
682         if (inode && !IS_ERR(inode)) {
683                 d_prune_aliases(inode);
684                 iput(inode);
685         }
686 out:
687         gfs2_glock_put(gl);
688 }
689 
690 static void glock_work_func(struct work_struct *work)
691 {
692         unsigned long delay = 0;
693         struct gfs2_glock *gl = container_of(work, struct gfs2_glock, gl_work.work);
694         unsigned int drop_refs = 1;
695 
696         if (test_and_clear_bit(GLF_REPLY_PENDING, &gl->gl_flags)) {
697                 finish_xmote(gl, gl->gl_reply);
698                 drop_refs++;
699         }
700         spin_lock(&gl->gl_lockref.lock);
701         if (test_bit(GLF_PENDING_DEMOTE, &gl->gl_flags) &&
702             gl->gl_state != LM_ST_UNLOCKED &&
703             gl->gl_demote_state != LM_ST_EXCLUSIVE) {
704                 unsigned long holdtime, now = jiffies;
705 
706                 holdtime = gl->gl_tchange + gl->gl_hold_time;
707                 if (time_before(now, holdtime))
708                         delay = holdtime - now;
709 
710                 if (!delay) {
711                         clear_bit(GLF_PENDING_DEMOTE, &gl->gl_flags);
712                         set_bit(GLF_DEMOTE, &gl->gl_flags);
713                 }
714         }
715         run_queue(gl, 0);
716         if (delay) {
717                 /* Keep one glock reference for the work we requeue. */
718                 drop_refs--;
719                 if (gl->gl_name.ln_type != LM_TYPE_INODE)
720                         delay = 0;
721                 __gfs2_glock_queue_work(gl, delay);
722         }
723 
724         /*
725          * Drop the remaining glock references manually here. (Mind that
726          * __gfs2_glock_queue_work depends on the lockref spinlock begin held
727          * here as well.)
728          */
729         gl->gl_lockref.count -= drop_refs;
730         if (!gl->gl_lockref.count) {
731                 __gfs2_glock_put(gl);
732                 return;
733         }
734         spin_unlock(&gl->gl_lockref.lock);
735 }
736 
737 static struct gfs2_glock *find_insert_glock(struct lm_lockname *name,
738                                             struct gfs2_glock *new)
739 {
740         struct wait_glock_queue wait;
741         wait_queue_head_t *wq = glock_waitqueue(name);
742         struct gfs2_glock *gl;
743 
744         wait.name = name;
745         init_wait(&wait.wait);
746         wait.wait.func = glock_wake_function;
747 
748 again:
749         prepare_to_wait(wq, &wait.wait, TASK_UNINTERRUPTIBLE);
750         rcu_read_lock();
751         if (new) {
752                 gl = rhashtable_lookup_get_insert_fast(&gl_hash_table,
753                         &new->gl_node, ht_parms);
754                 if (IS_ERR(gl))
755                         goto out;
756         } else {
757                 gl = rhashtable_lookup_fast(&gl_hash_table,
758                         name, ht_parms);
759         }
760         if (gl && !lockref_get_not_dead(&gl->gl_lockref)) {
761                 rcu_read_unlock();
762                 schedule();
763                 goto again;
764         }
765 out:
766         rcu_read_unlock();
767         finish_wait(wq, &wait.wait);
768         return gl;
769 }
770 
771 /**
772  * gfs2_glock_get() - Get a glock, or create one if one doesn't exist
773  * @sdp: The GFS2 superblock
774  * @number: the lock number
775  * @glops: The glock_operations to use
776  * @create: If 0, don't create the glock if it doesn't exist
777  * @glp: the glock is returned here
778  *
779  * This does not lock a glock, just finds/creates structures for one.
780  *
781  * Returns: errno
782  */
783 
784 int gfs2_glock_get(struct gfs2_sbd *sdp, u64 number,
785                    const struct gfs2_glock_operations *glops, int create,
786                    struct gfs2_glock **glp)
787 {
788         struct super_block *s = sdp->sd_vfs;
789         struct lm_lockname name = { .ln_number = number,
790                                     .ln_type = glops->go_type,
791                                     .ln_sbd = sdp };
792         struct gfs2_glock *gl, *tmp;
793         struct address_space *mapping;
794         struct kmem_cache *cachep;
795         int ret = 0;
796 
797         gl = find_insert_glock(&name, NULL);
798         if (gl) {
799                 *glp = gl;
800                 return 0;
801         }
802         if (!create)
803                 return -ENOENT;
804 
805         if (glops->go_flags & GLOF_ASPACE)
806                 cachep = gfs2_glock_aspace_cachep;
807         else
808                 cachep = gfs2_glock_cachep;
809         gl = kmem_cache_alloc(cachep, GFP_NOFS);
810         if (!gl)
811                 return -ENOMEM;
812 
813         memset(&gl->gl_lksb, 0, sizeof(struct dlm_lksb));
814 
815         if (glops->go_flags & GLOF_LVB) {
816                 gl->gl_lksb.sb_lvbptr = kzalloc(GFS2_MIN_LVB_SIZE, GFP_NOFS);
817                 if (!gl->gl_lksb.sb_lvbptr) {
818                         kmem_cache_free(cachep, gl);
819                         return -ENOMEM;
820                 }
821         }
822 
823         atomic_inc(&sdp->sd_glock_disposal);
824         gl->gl_node.next = NULL;
825         gl->gl_flags = 0;
826         gl->gl_name = name;
827         gl->gl_lockref.count = 1;
828         gl->gl_state = LM_ST_UNLOCKED;
829         gl->gl_target = LM_ST_UNLOCKED;
830         gl->gl_demote_state = LM_ST_EXCLUSIVE;
831         gl->gl_ops = glops;
832         gl->gl_dstamp = 0;
833         preempt_disable();
834         /* We use the global stats to estimate the initial per-glock stats */
835         gl->gl_stats = this_cpu_ptr(sdp->sd_lkstats)->lkstats[glops->go_type];
836         preempt_enable();
837         gl->gl_stats.stats[GFS2_LKS_DCOUNT] = 0;
838         gl->gl_stats.stats[GFS2_LKS_QCOUNT] = 0;
839         gl->gl_tchange = jiffies;
840         gl->gl_object = NULL;
841         gl->gl_hold_time = GL_GLOCK_DFT_HOLD;
842         INIT_DELAYED_WORK(&gl->gl_work, glock_work_func);
843         INIT_WORK(&gl->gl_delete, delete_work_func);
844 
845         mapping = gfs2_glock2aspace(gl);
846         if (mapping) {
847                 mapping->a_ops = &gfs2_meta_aops;
848                 mapping->host = s->s_bdev->bd_inode;
849                 mapping->flags = 0;
850                 mapping_set_gfp_mask(mapping, GFP_NOFS);
851                 mapping->private_data = NULL;
852                 mapping->writeback_index = 0;
853         }
854 
855         tmp = find_insert_glock(&name, gl);
856         if (!tmp) {
857                 *glp = gl;
858                 goto out;
859         }
860         if (IS_ERR(tmp)) {
861                 ret = PTR_ERR(tmp);
862                 goto out_free;
863         }
864         *glp = tmp;
865 
866 out_free:
867         kfree(gl->gl_lksb.sb_lvbptr);
868         kmem_cache_free(cachep, gl);
869         atomic_dec(&sdp->sd_glock_disposal);
870 
871 out:
872         return ret;
873 }
874 
875 /**
876  * gfs2_holder_init - initialize a struct gfs2_holder in the default way
877  * @gl: the glock
878  * @state: the state we're requesting
879  * @flags: the modifier flags
880  * @gh: the holder structure
881  *
882  */
883 
884 void gfs2_holder_init(struct gfs2_glock *gl, unsigned int state, u16 flags,
885                       struct gfs2_holder *gh)
886 {
887         INIT_LIST_HEAD(&gh->gh_list);
888         gh->gh_gl = gl;
889         gh->gh_ip = _RET_IP_;
890         gh->gh_owner_pid = get_pid(task_pid(current));
891         gh->gh_state = state;
892         gh->gh_flags = flags;
893         gh->gh_error = 0;
894         gh->gh_iflags = 0;
895         gfs2_glock_hold(gl);
896 }
897 
898 /**
899  * gfs2_holder_reinit - reinitialize a struct gfs2_holder so we can requeue it
900  * @state: the state we're requesting
901  * @flags: the modifier flags
902  * @gh: the holder structure
903  *
904  * Don't mess with the glock.
905  *
906  */
907 
908 void gfs2_holder_reinit(unsigned int state, u16 flags, struct gfs2_holder *gh)
909 {
910         gh->gh_state = state;
911         gh->gh_flags = flags;
912         gh->gh_iflags = 0;
913         gh->gh_ip = _RET_IP_;
914         put_pid(gh->gh_owner_pid);
915         gh->gh_owner_pid = get_pid(task_pid(current));
916 }
917 
918 /**
919  * gfs2_holder_uninit - uninitialize a holder structure (drop glock reference)
920  * @gh: the holder structure
921  *
922  */
923 
924 void gfs2_holder_uninit(struct gfs2_holder *gh)
925 {
926         put_pid(gh->gh_owner_pid);
927         gfs2_glock_put(gh->gh_gl);
928         gfs2_holder_mark_uninitialized(gh);
929         gh->gh_ip = 0;
930 }
931 
932 /**
933  * gfs2_glock_wait - wait on a glock acquisition
934  * @gh: the glock holder
935  *
936  * Returns: 0 on success
937  */
938 
939 int gfs2_glock_wait(struct gfs2_holder *gh)
940 {
941         unsigned long time1 = jiffies;
942 
943         might_sleep();
944         wait_on_bit(&gh->gh_iflags, HIF_WAIT, TASK_UNINTERRUPTIBLE);
945         if (time_after(jiffies, time1 + HZ)) /* have we waited > a second? */
946                 /* Lengthen the minimum hold time. */
947                 gh->gh_gl->gl_hold_time = min(gh->gh_gl->gl_hold_time +
948                                               GL_GLOCK_HOLD_INCR,
949                                               GL_GLOCK_MAX_HOLD);
950         return gh->gh_error;
951 }
952 
953 /**
954  * handle_callback - process a demote request
955  * @gl: the glock
956  * @state: the state the caller wants us to change to
957  *
958  * There are only two requests that we are going to see in actual
959  * practise: LM_ST_SHARED and LM_ST_UNLOCKED
960  */
961 
962 static void handle_callback(struct gfs2_glock *gl, unsigned int state,
963                             unsigned long delay, bool remote)
964 {
965         int bit = delay ? GLF_PENDING_DEMOTE : GLF_DEMOTE;
966 
967         set_bit(bit, &gl->gl_flags);
968         if (gl->gl_demote_state == LM_ST_EXCLUSIVE) {
969                 gl->gl_demote_state = state;
970                 gl->gl_demote_time = jiffies;
971         } else if (gl->gl_demote_state != LM_ST_UNLOCKED &&
972                         gl->gl_demote_state != state) {
973                 gl->gl_demote_state = LM_ST_UNLOCKED;
974         }
975         if (gl->gl_ops->go_callback)
976                 gl->gl_ops->go_callback(gl, remote);
977         trace_gfs2_demote_rq(gl, remote);
978 }
979 
980 void gfs2_print_dbg(struct seq_file *seq, const char *fmt, ...)
981 {
982         struct va_format vaf;
983         va_list args;
984 
985         va_start(args, fmt);
986 
987         if (seq) {
988                 seq_vprintf(seq, fmt, args);
989         } else {
990                 vaf.fmt = fmt;
991                 vaf.va = &args;
992 
993                 pr_err("%pV", &vaf);
994         }
995 
996         va_end(args);
997 }
998 
999 /**
1000  * add_to_queue - Add a holder to the wait queue (but look for recursion)
1001  * @gh: the holder structure to add
1002  *
1003  * Eventually we should move the recursive locking trap to a
1004  * debugging option or something like that. This is the fast
1005  * path and needs to have the minimum number of distractions.
1006  * 
1007  */
1008 
1009 static inline void add_to_queue(struct gfs2_holder *gh)
1010 __releases(&gl->gl_lockref.lock)
1011 __acquires(&gl->gl_lockref.lock)
1012 {
1013         struct gfs2_glock *gl = gh->gh_gl;
1014         struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
1015         struct list_head *insert_pt = NULL;
1016         struct gfs2_holder *gh2;
1017         int try_futile = 0;
1018 
1019         BUG_ON(gh->gh_owner_pid == NULL);
1020         if (test_and_set_bit(HIF_WAIT, &gh->gh_iflags))
1021                 BUG();
1022 
1023         if (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)) {
1024                 if (test_bit(GLF_LOCK, &gl->gl_flags))
1025                         try_futile = !may_grant(gl, gh);
1026                 if (test_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags))
1027                         goto fail;
1028         }
1029 
1030         list_for_each_entry(gh2, &gl->gl_holders, gh_list) {
1031                 if (unlikely(gh2->gh_owner_pid == gh->gh_owner_pid &&
1032                     (gh->gh_gl->gl_ops->go_type != LM_TYPE_FLOCK)))
1033                         goto trap_recursive;
1034                 if (try_futile &&
1035                     !(gh2->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB))) {
1036 fail:
1037                         gh->gh_error = GLR_TRYFAILED;
1038                         gfs2_holder_wake(gh);
1039                         return;
1040                 }
1041                 if (test_bit(HIF_HOLDER, &gh2->gh_iflags))
1042                         continue;
1043                 if (unlikely((gh->gh_flags & LM_FLAG_PRIORITY) && !insert_pt))
1044                         insert_pt = &gh2->gh_list;
1045         }
1046         set_bit(GLF_QUEUED, &gl->gl_flags);
1047         trace_gfs2_glock_queue(gh, 1);
1048         gfs2_glstats_inc(gl, GFS2_LKS_QCOUNT);
1049         gfs2_sbstats_inc(gl, GFS2_LKS_QCOUNT);
1050         if (likely(insert_pt == NULL)) {
1051                 list_add_tail(&gh->gh_list, &gl->gl_holders);
1052                 if (unlikely(gh->gh_flags & LM_FLAG_PRIORITY))
1053                         goto do_cancel;
1054                 return;
1055         }
1056         list_add_tail(&gh->gh_list, insert_pt);
1057 do_cancel:
1058         gh = list_entry(gl->gl_holders.next, struct gfs2_holder, gh_list);
1059         if (!(gh->gh_flags & LM_FLAG_PRIORITY)) {
1060                 spin_unlock(&gl->gl_lockref.lock);
1061                 if (sdp->sd_lockstruct.ls_ops->lm_cancel)
1062                         sdp->sd_lockstruct.ls_ops->lm_cancel(gl);
1063                 spin_lock(&gl->gl_lockref.lock);
1064         }
1065         return;
1066 
1067 trap_recursive:
1068         fs_err(sdp, "original: %pSR\n", (void *)gh2->gh_ip);
1069         fs_err(sdp, "pid: %d\n", pid_nr(gh2->gh_owner_pid));
1070         fs_err(sdp, "lock type: %d req lock state : %d\n",
1071                gh2->gh_gl->gl_name.ln_type, gh2->gh_state);
1072         fs_err(sdp, "new: %pSR\n", (void *)gh->gh_ip);
1073         fs_err(sdp, "pid: %d\n", pid_nr(gh->gh_owner_pid));
1074         fs_err(sdp, "lock type: %d req lock state : %d\n",
1075                gh->gh_gl->gl_name.ln_type, gh->gh_state);
1076         gfs2_dump_glock(NULL, gl);
1077         BUG();
1078 }
1079 
1080 /**
1081  * gfs2_glock_nq - enqueue a struct gfs2_holder onto a glock (acquire a glock)
1082  * @gh: the holder structure
1083  *
1084  * if (gh->gh_flags & GL_ASYNC), this never returns an error
1085  *
1086  * Returns: 0, GLR_TRYFAILED, or errno on failure
1087  */
1088 
1089 int gfs2_glock_nq(struct gfs2_holder *gh)
1090 {
1091         struct gfs2_glock *gl = gh->gh_gl;
1092         struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
1093         int error = 0;
1094 
1095         if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
1096                 return -EIO;
1097 
1098         if (test_bit(GLF_LRU, &gl->gl_flags))
1099                 gfs2_glock_remove_from_lru(gl);
1100 
1101         spin_lock(&gl->gl_lockref.lock);
1102         add_to_queue(gh);
1103         if (unlikely((LM_FLAG_NOEXP & gh->gh_flags) &&
1104                      test_and_clear_bit(GLF_FROZEN, &gl->gl_flags))) {
1105                 set_bit(GLF_REPLY_PENDING, &gl->gl_flags);
1106                 gl->gl_lockref.count++;
1107                 __gfs2_glock_queue_work(gl, 0);
1108         }
1109         run_queue(gl, 1);
1110         spin_unlock(&gl->gl_lockref.lock);
1111 
1112         if (!(gh->gh_flags & GL_ASYNC))
1113                 error = gfs2_glock_wait(gh);
1114 
1115         return error;
1116 }
1117 
1118 /**
1119  * gfs2_glock_poll - poll to see if an async request has been completed
1120  * @gh: the holder
1121  *
1122  * Returns: 1 if the request is ready to be gfs2_glock_wait()ed on
1123  */
1124 
1125 int gfs2_glock_poll(struct gfs2_holder *gh)
1126 {
1127         return test_bit(HIF_WAIT, &gh->gh_iflags) ? 0 : 1;
1128 }
1129 
1130 /**
1131  * gfs2_glock_dq - dequeue a struct gfs2_holder from a glock (release a glock)
1132  * @gh: the glock holder
1133  *
1134  */
1135 
1136 void gfs2_glock_dq(struct gfs2_holder *gh)
1137 {
1138         struct gfs2_glock *gl = gh->gh_gl;
1139         const struct gfs2_glock_operations *glops = gl->gl_ops;
1140         unsigned delay = 0;
1141         int fast_path = 0;
1142 
1143         spin_lock(&gl->gl_lockref.lock);
1144         if (gh->gh_flags & GL_NOCACHE)
1145                 handle_callback(gl, LM_ST_UNLOCKED, 0, false);
1146 
1147         list_del_init(&gh->gh_list);
1148         clear_bit(HIF_HOLDER, &gh->gh_iflags);
1149         if (find_first_holder(gl) == NULL) {
1150                 if (glops->go_unlock) {
1151                         GLOCK_BUG_ON(gl, test_and_set_bit(GLF_LOCK, &gl->gl_flags));
1152                         spin_unlock(&gl->gl_lockref.lock);
1153                         glops->go_unlock(gh);
1154                         spin_lock(&gl->gl_lockref.lock);
1155                         clear_bit(GLF_LOCK, &gl->gl_flags);
1156                 }
1157                 if (list_empty(&gl->gl_holders) &&
1158                     !test_bit(GLF_PENDING_DEMOTE, &gl->gl_flags) &&
1159                     !test_bit(GLF_DEMOTE, &gl->gl_flags))
1160                         fast_path = 1;
1161         }
1162         if (!test_bit(GLF_LFLUSH, &gl->gl_flags) && demote_ok(gl) &&
1163             (glops->go_flags & GLOF_LRU))
1164                 gfs2_glock_add_to_lru(gl);
1165 
1166         trace_gfs2_glock_queue(gh, 0);
1167         if (unlikely(!fast_path)) {
1168                 gl->gl_lockref.count++;
1169                 if (test_bit(GLF_PENDING_DEMOTE, &gl->gl_flags) &&
1170                     !test_bit(GLF_DEMOTE, &gl->gl_flags) &&
1171                     gl->gl_name.ln_type == LM_TYPE_INODE)
1172                         delay = gl->gl_hold_time;
1173                 __gfs2_glock_queue_work(gl, delay);
1174         }
1175         spin_unlock(&gl->gl_lockref.lock);
1176 }
1177 
1178 void gfs2_glock_dq_wait(struct gfs2_holder *gh)
1179 {
1180         struct gfs2_glock *gl = gh->gh_gl;
1181         gfs2_glock_dq(gh);
1182         might_sleep();
1183         wait_on_bit(&gl->gl_flags, GLF_DEMOTE, TASK_UNINTERRUPTIBLE);
1184 }
1185 
1186 /**
1187  * gfs2_glock_dq_uninit - dequeue a holder from a glock and initialize it
1188  * @gh: the holder structure
1189  *
1190  */
1191 
1192 void gfs2_glock_dq_uninit(struct gfs2_holder *gh)
1193 {
1194         gfs2_glock_dq(gh);
1195         gfs2_holder_uninit(gh);
1196 }
1197 
1198 /**
1199  * gfs2_glock_nq_num - acquire a glock based on lock number
1200  * @sdp: the filesystem
1201  * @number: the lock number
1202  * @glops: the glock operations for the type of glock
1203  * @state: the state to acquire the glock in
1204  * @flags: modifier flags for the acquisition
1205  * @gh: the struct gfs2_holder
1206  *
1207  * Returns: errno
1208  */
1209 
1210 int gfs2_glock_nq_num(struct gfs2_sbd *sdp, u64 number,
1211                       const struct gfs2_glock_operations *glops,
1212                       unsigned int state, u16 flags, struct gfs2_holder *gh)
1213 {
1214         struct gfs2_glock *gl;
1215         int error;
1216 
1217         error = gfs2_glock_get(sdp, number, glops, CREATE, &gl);
1218         if (!error) {
1219                 error = gfs2_glock_nq_init(gl, state, flags, gh);
1220                 gfs2_glock_put(gl);
1221         }
1222 
1223         return error;
1224 }
1225 
1226 /**
1227  * glock_compare - Compare two struct gfs2_glock structures for sorting
1228  * @arg_a: the first structure
1229  * @arg_b: the second structure
1230  *
1231  */
1232 
1233 static int glock_compare(const void *arg_a, const void *arg_b)
1234 {
1235         const struct gfs2_holder *gh_a = *(const struct gfs2_holder **)arg_a;
1236         const struct gfs2_holder *gh_b = *(const struct gfs2_holder **)arg_b;
1237         const struct lm_lockname *a = &gh_a->gh_gl->gl_name;
1238         const struct lm_lockname *b = &gh_b->gh_gl->gl_name;
1239 
1240         if (a->ln_number > b->ln_number)
1241                 return 1;
1242         if (a->ln_number < b->ln_number)
1243                 return -1;
1244         BUG_ON(gh_a->gh_gl->gl_ops->go_type == gh_b->gh_gl->gl_ops->go_type);
1245         return 0;
1246 }
1247 
1248 /**
1249  * nq_m_sync - synchonously acquire more than one glock in deadlock free order
1250  * @num_gh: the number of structures
1251  * @ghs: an array of struct gfs2_holder structures
1252  *
1253  * Returns: 0 on success (all glocks acquired),
1254  *          errno on failure (no glocks acquired)
1255  */
1256 
1257 static int nq_m_sync(unsigned int num_gh, struct gfs2_holder *ghs,
1258                      struct gfs2_holder **p)
1259 {
1260         unsigned int x;
1261         int error = 0;
1262 
1263         for (x = 0; x < num_gh; x++)
1264                 p[x] = &ghs[x];
1265 
1266         sort(p, num_gh, sizeof(struct gfs2_holder *), glock_compare, NULL);
1267 
1268         for (x = 0; x < num_gh; x++) {
1269                 p[x]->gh_flags &= ~(LM_FLAG_TRY | GL_ASYNC);
1270 
1271                 error = gfs2_glock_nq(p[x]);
1272                 if (error) {
1273                         while (x--)
1274                                 gfs2_glock_dq(p[x]);
1275                         break;
1276                 }
1277         }
1278 
1279         return error;
1280 }
1281 
1282 /**
1283  * gfs2_glock_nq_m - acquire multiple glocks
1284  * @num_gh: the number of structures
1285  * @ghs: an array of struct gfs2_holder structures
1286  *
1287  *
1288  * Returns: 0 on success (all glocks acquired),
1289  *          errno on failure (no glocks acquired)
1290  */
1291 
1292 int gfs2_glock_nq_m(unsigned int num_gh, struct gfs2_holder *ghs)
1293 {
1294         struct gfs2_holder *tmp[4];
1295         struct gfs2_holder **pph = tmp;
1296         int error = 0;
1297 
1298         switch(num_gh) {
1299         case 0:
1300                 return 0;
1301         case 1:
1302                 ghs->gh_flags &= ~(LM_FLAG_TRY | GL_ASYNC);
1303                 return gfs2_glock_nq(ghs);
1304         default:
1305                 if (num_gh <= 4)
1306                         break;
1307                 pph = kmalloc_array(num_gh, sizeof(struct gfs2_holder *),
1308                                     GFP_NOFS);
1309                 if (!pph)
1310                         return -ENOMEM;
1311         }
1312 
1313         error = nq_m_sync(num_gh, ghs, pph);
1314 
1315         if (pph != tmp)
1316                 kfree(pph);
1317 
1318         return error;
1319 }
1320 
1321 /**
1322  * gfs2_glock_dq_m - release multiple glocks
1323  * @num_gh: the number of structures
1324  * @ghs: an array of struct gfs2_holder structures
1325  *
1326  */
1327 
1328 void gfs2_glock_dq_m(unsigned int num_gh, struct gfs2_holder *ghs)
1329 {
1330         while (num_gh--)
1331                 gfs2_glock_dq(&ghs[num_gh]);
1332 }
1333 
1334 void gfs2_glock_cb(struct gfs2_glock *gl, unsigned int state)
1335 {
1336         unsigned long delay = 0;
1337         unsigned long holdtime;
1338         unsigned long now = jiffies;
1339 
1340         gfs2_glock_hold(gl);
1341         holdtime = gl->gl_tchange + gl->gl_hold_time;
1342         if (test_bit(GLF_QUEUED, &gl->gl_flags) &&
1343             gl->gl_name.ln_type == LM_TYPE_INODE) {
1344                 if (time_before(now, holdtime))
1345                         delay = holdtime - now;
1346                 if (test_bit(GLF_REPLY_PENDING, &gl->gl_flags))
1347                         delay = gl->gl_hold_time;
1348         }
1349 
1350         spin_lock(&gl->gl_lockref.lock);
1351         handle_callback(gl, state, delay, true);
1352         __gfs2_glock_queue_work(gl, delay);
1353         spin_unlock(&gl->gl_lockref.lock);
1354 }
1355 
1356 /**
1357  * gfs2_should_freeze - Figure out if glock should be frozen
1358  * @gl: The glock in question
1359  *
1360  * Glocks are not frozen if (a) the result of the dlm operation is
1361  * an error, (b) the locking operation was an unlock operation or
1362  * (c) if there is a "noexp" flagged request anywhere in the queue
1363  *
1364  * Returns: 1 if freezing should occur, 0 otherwise
1365  */
1366 
1367 static int gfs2_should_freeze(const struct gfs2_glock *gl)
1368 {
1369         const struct gfs2_holder *gh;
1370 
1371         if (gl->gl_reply & ~LM_OUT_ST_MASK)
1372                 return 0;
1373         if (gl->gl_target == LM_ST_UNLOCKED)
1374                 return 0;
1375 
1376         list_for_each_entry(gh, &gl->gl_holders, gh_list) {
1377                 if (test_bit(HIF_HOLDER, &gh->gh_iflags))
1378                         continue;
1379                 if (LM_FLAG_NOEXP & gh->gh_flags)
1380                         return 0;
1381         }
1382 
1383         return 1;
1384 }
1385 
1386 /**
1387  * gfs2_glock_complete - Callback used by locking
1388  * @gl: Pointer to the glock
1389  * @ret: The return value from the dlm
1390  *
1391  * The gl_reply field is under the gl_lockref.lock lock so that it is ok
1392  * to use a bitfield shared with other glock state fields.
1393  */
1394 
1395 void gfs2_glock_complete(struct gfs2_glock *gl, int ret)
1396 {
1397         struct lm_lockstruct *ls = &gl->gl_name.ln_sbd->sd_lockstruct;
1398 
1399         spin_lock(&gl->gl_lockref.lock);
1400         gl->gl_reply = ret;
1401 
1402         if (unlikely(test_bit(DFL_BLOCK_LOCKS, &ls->ls_recover_flags))) {
1403                 if (gfs2_should_freeze(gl)) {
1404                         set_bit(GLF_FROZEN, &gl->gl_flags);
1405                         spin_unlock(&gl->gl_lockref.lock);
1406                         return;
1407                 }
1408         }
1409 
1410         gl->gl_lockref.count++;
1411         set_bit(GLF_REPLY_PENDING, &gl->gl_flags);
1412         __gfs2_glock_queue_work(gl, 0);
1413         spin_unlock(&gl->gl_lockref.lock);
1414 }
1415 
1416 static int glock_cmp(void *priv, struct list_head *a, struct list_head *b)
1417 {
1418         struct gfs2_glock *gla, *glb;
1419 
1420         gla = list_entry(a, struct gfs2_glock, gl_lru);
1421         glb = list_entry(b, struct gfs2_glock, gl_lru);
1422 
1423         if (gla->gl_name.ln_number > glb->gl_name.ln_number)
1424                 return 1;
1425         if (gla->gl_name.ln_number < glb->gl_name.ln_number)
1426                 return -1;
1427 
1428         return 0;
1429 }
1430 
1431 /**
1432  * gfs2_dispose_glock_lru - Demote a list of glocks
1433  * @list: The list to dispose of
1434  *
1435  * Disposing of glocks may involve disk accesses, so that here we sort
1436  * the glocks by number (i.e. disk location of the inodes) so that if
1437  * there are any such accesses, they'll be sent in order (mostly).
1438  *
1439  * Must be called under the lru_lock, but may drop and retake this
1440  * lock. While the lru_lock is dropped, entries may vanish from the
1441  * list, but no new entries will appear on the list (since it is
1442  * private)
1443  */
1444 
1445 static void gfs2_dispose_glock_lru(struct list_head *list)
1446 __releases(&lru_lock)
1447 __acquires(&lru_lock)
1448 {
1449         struct gfs2_glock *gl;
1450 
1451         list_sort(NULL, list, glock_cmp);
1452 
1453         while(!list_empty(list)) {
1454                 gl = list_entry(list->next, struct gfs2_glock, gl_lru);
1455                 list_del_init(&gl->gl_lru);
1456                 if (!spin_trylock(&gl->gl_lockref.lock)) {
1457 add_back_to_lru:
1458                         list_add(&gl->gl_lru, &lru_list);
1459                         atomic_inc(&lru_count);
1460                         continue;
1461                 }
1462                 if (test_and_set_bit(GLF_LOCK, &gl->gl_flags)) {
1463                         spin_unlock(&gl->gl_lockref.lock);
1464                         goto add_back_to_lru;
1465                 }
1466                 clear_bit(GLF_LRU, &gl->gl_flags);
1467                 gl->gl_lockref.count++;
1468                 if (demote_ok(gl))
1469                         handle_callback(gl, LM_ST_UNLOCKED, 0, false);
1470                 WARN_ON(!test_and_clear_bit(GLF_LOCK, &gl->gl_flags));
1471                 __gfs2_glock_queue_work(gl, 0);
1472                 spin_unlock(&gl->gl_lockref.lock);
1473                 cond_resched_lock(&lru_lock);
1474         }
1475 }
1476 
1477 /**
1478  * gfs2_scan_glock_lru - Scan the LRU looking for locks to demote
1479  * @nr: The number of entries to scan
1480  *
1481  * This function selects the entries on the LRU which are able to
1482  * be demoted, and then kicks off the process by calling
1483  * gfs2_dispose_glock_lru() above.
1484  */
1485 
1486 static long gfs2_scan_glock_lru(int nr)
1487 {
1488         struct gfs2_glock *gl;
1489         LIST_HEAD(skipped);
1490         LIST_HEAD(dispose);
1491         long freed = 0;
1492 
1493         spin_lock(&lru_lock);
1494         while ((nr-- >= 0) && !list_empty(&lru_list)) {
1495                 gl = list_entry(lru_list.next, struct gfs2_glock, gl_lru);
1496 
1497                 /* Test for being demotable */
1498                 if (!test_bit(GLF_LOCK, &gl->gl_flags)) {
1499                         list_move(&gl->gl_lru, &dispose);
1500                         atomic_dec(&lru_count);
1501                         freed++;
1502                         continue;
1503                 }
1504 
1505                 list_move(&gl->gl_lru, &skipped);
1506         }
1507         list_splice(&skipped, &lru_list);
1508         if (!list_empty(&dispose))
1509                 gfs2_dispose_glock_lru(&dispose);
1510         spin_unlock(&lru_lock);
1511 
1512         return freed;
1513 }
1514 
1515 static unsigned long gfs2_glock_shrink_scan(struct shrinker *shrink,
1516                                             struct shrink_control *sc)
1517 {
1518         if (!(sc->gfp_mask & __GFP_FS))
1519                 return SHRINK_STOP;
1520         return gfs2_scan_glock_lru(sc->nr_to_scan);
1521 }
1522 
1523 static unsigned long gfs2_glock_shrink_count(struct shrinker *shrink,
1524                                              struct shrink_control *sc)
1525 {
1526         return vfs_pressure_ratio(atomic_read(&lru_count));
1527 }
1528 
1529 static struct shrinker glock_shrinker = {
1530         .seeks = DEFAULT_SEEKS,
1531         .count_objects = gfs2_glock_shrink_count,
1532         .scan_objects = gfs2_glock_shrink_scan,
1533 };
1534 
1535 /**
1536  * examine_bucket - Call a function for glock in a hash bucket
1537  * @examiner: the function
1538  * @sdp: the filesystem
1539  * @bucket: the bucket
1540  *
1541  * Note that the function can be called multiple times on the same
1542  * object.  So the user must ensure that the function can cope with
1543  * that.
1544  */
1545 
1546 static void glock_hash_walk(glock_examiner examiner, const struct gfs2_sbd *sdp)
1547 {
1548         struct gfs2_glock *gl;
1549         struct rhashtable_iter iter;
1550 
1551         rhashtable_walk_enter(&gl_hash_table, &iter);
1552 
1553         do {
1554                 rhashtable_walk_start(&iter);
1555 
1556                 while ((gl = rhashtable_walk_next(&iter)) && !IS_ERR(gl))
1557                         if (gl->gl_name.ln_sbd == sdp &&
1558                             lockref_get_not_dead(&gl->gl_lockref))
1559                                 examiner(gl);
1560 
1561                 rhashtable_walk_stop(&iter);
1562         } while (cond_resched(), gl == ERR_PTR(-EAGAIN));
1563 
1564         rhashtable_walk_exit(&iter);
1565 }
1566 
1567 /**
1568  * thaw_glock - thaw out a glock which has an unprocessed reply waiting
1569  * @gl: The glock to thaw
1570  *
1571  */
1572 
1573 static void thaw_glock(struct gfs2_glock *gl)
1574 {
1575         if (!test_and_clear_bit(GLF_FROZEN, &gl->gl_flags)) {
1576                 gfs2_glock_put(gl);
1577                 return;
1578         }
1579         set_bit(GLF_REPLY_PENDING, &gl->gl_flags);
1580         gfs2_glock_queue_work(gl, 0);
1581 }
1582 
1583 /**
1584  * clear_glock - look at a glock and see if we can free it from glock cache
1585  * @gl: the glock to look at
1586  *
1587  */
1588 
1589 static void clear_glock(struct gfs2_glock *gl)
1590 {
1591         gfs2_glock_remove_from_lru(gl);
1592 
1593         spin_lock(&gl->gl_lockref.lock);
1594         if (gl->gl_state != LM_ST_UNLOCKED)
1595                 handle_callback(gl, LM_ST_UNLOCKED, 0, false);
1596         __gfs2_glock_queue_work(gl, 0);
1597         spin_unlock(&gl->gl_lockref.lock);
1598 }
1599 
1600 /**
1601  * gfs2_glock_thaw - Thaw any frozen glocks
1602  * @sdp: The super block
1603  *
1604  */
1605 
1606 void gfs2_glock_thaw(struct gfs2_sbd *sdp)
1607 {
1608         glock_hash_walk(thaw_glock, sdp);
1609 }
1610 
1611 static void dump_glock(struct seq_file *seq, struct gfs2_glock *gl)
1612 {
1613         spin_lock(&gl->gl_lockref.lock);
1614         gfs2_dump_glock(seq, gl);
1615         spin_unlock(&gl->gl_lockref.lock);
1616 }
1617 
1618 static void dump_glock_func(struct gfs2_glock *gl)
1619 {
1620         dump_glock(NULL, gl);
1621 }
1622 
1623 /**
1624  * gfs2_gl_hash_clear - Empty out the glock hash table
1625  * @sdp: the filesystem
1626  * @wait: wait until it's all gone
1627  *
1628  * Called when unmounting the filesystem.
1629  */
1630 
1631 void gfs2_gl_hash_clear(struct gfs2_sbd *sdp)
1632 {
1633         set_bit(SDF_SKIP_DLM_UNLOCK, &sdp->sd_flags);
1634         flush_workqueue(glock_workqueue);
1635         glock_hash_walk(clear_glock, sdp);
1636         flush_workqueue(glock_workqueue);
1637         wait_event_timeout(sdp->sd_glock_wait,
1638                            atomic_read(&sdp->sd_glock_disposal) == 0,
1639                            HZ * 600);
1640         glock_hash_walk(dump_glock_func, sdp);
1641 }
1642 
1643 void gfs2_glock_finish_truncate(struct gfs2_inode *ip)
1644 {
1645         struct gfs2_glock *gl = ip->i_gl;
1646         int ret;
1647 
1648         ret = gfs2_truncatei_resume(ip);
1649         gfs2_assert_withdraw(gl->gl_name.ln_sbd, ret == 0);
1650 
1651         spin_lock(&gl->gl_lockref.lock);
1652         clear_bit(GLF_LOCK, &gl->gl_flags);
1653         run_queue(gl, 1);
1654         spin_unlock(&gl->gl_lockref.lock);
1655 }
1656 
1657 static const char *state2str(unsigned state)
1658 {
1659         switch(state) {
1660         case LM_ST_UNLOCKED:
1661                 return "UN";
1662         case LM_ST_SHARED:
1663                 return "SH";
1664         case LM_ST_DEFERRED:
1665                 return "DF";
1666         case LM_ST_EXCLUSIVE:
1667                 return "EX";
1668         }
1669         return "??";
1670 }
1671 
1672 static const char *hflags2str(char *buf, u16 flags, unsigned long iflags)
1673 {
1674         char *p = buf;
1675         if (flags & LM_FLAG_TRY)
1676                 *p++ = 't';
1677         if (flags & LM_FLAG_TRY_1CB)
1678                 *p++ = 'T';
1679         if (flags & LM_FLAG_NOEXP)
1680                 *p++ = 'e';
1681         if (flags & LM_FLAG_ANY)
1682                 *p++ = 'A';
1683         if (flags & LM_FLAG_PRIORITY)
1684                 *p++ = 'p';
1685         if (flags & GL_ASYNC)
1686                 *p++ = 'a';
1687         if (flags & GL_EXACT)
1688                 *p++ = 'E';
1689         if (flags & GL_NOCACHE)
1690                 *p++ = 'c';
1691         if (test_bit(HIF_HOLDER, &iflags))
1692                 *p++ = 'H';
1693         if (test_bit(HIF_WAIT, &iflags))
1694                 *p++ = 'W';
1695         if (test_bit(HIF_FIRST, &iflags))
1696                 *p++ = 'F';
1697         *p = 0;
1698         return buf;
1699 }
1700 
1701 /**
1702  * dump_holder - print information about a glock holder
1703  * @seq: the seq_file struct
1704  * @gh: the glock holder
1705  *
1706  */
1707 
1708 static void dump_holder(struct seq_file *seq, const struct gfs2_holder *gh)
1709 {
1710         struct task_struct *gh_owner = NULL;
1711         char flags_buf[32];
1712 
1713         rcu_read_lock();
1714         if (gh->gh_owner_pid)
1715                 gh_owner = pid_task(gh->gh_owner_pid, PIDTYPE_PID);
1716         gfs2_print_dbg(seq, " H: s:%s f:%s e:%d p:%ld [%s] %pS\n",
1717                        state2str(gh->gh_state),
1718                        hflags2str(flags_buf, gh->gh_flags, gh->gh_iflags),
1719                        gh->gh_error,
1720                        gh->gh_owner_pid ? (long)pid_nr(gh->gh_owner_pid) : -1,
1721                        gh_owner ? gh_owner->comm : "(ended)",
1722                        (void *)gh->gh_ip);
1723         rcu_read_unlock();
1724 }
1725 
1726 static const char *gflags2str(char *buf, const struct gfs2_glock *gl)
1727 {
1728         const unsigned long *gflags = &gl->gl_flags;
1729         char *p = buf;
1730 
1731         if (test_bit(GLF_LOCK, gflags))
1732                 *p++ = 'l';
1733         if (test_bit(GLF_DEMOTE, gflags))
1734                 *p++ = 'D';
1735         if (test_bit(GLF_PENDING_DEMOTE, gflags))
1736                 *p++ = 'd';
1737         if (test_bit(GLF_DEMOTE_IN_PROGRESS, gflags))
1738                 *p++ = 'p';
1739         if (test_bit(GLF_DIRTY, gflags))
1740                 *p++ = 'y';
1741         if (test_bit(GLF_LFLUSH, gflags))
1742                 *p++ = 'f';
1743         if (test_bit(GLF_INVALIDATE_IN_PROGRESS, gflags))
1744                 *p++ = 'i';
1745         if (test_bit(GLF_REPLY_PENDING, gflags))
1746                 *p++ = 'r';
1747         if (test_bit(GLF_INITIAL, gflags))
1748                 *p++ = 'I';
1749         if (test_bit(GLF_FROZEN, gflags))
1750                 *p++ = 'F';
1751         if (test_bit(GLF_QUEUED, gflags))
1752                 *p++ = 'q';
1753         if (test_bit(GLF_LRU, gflags))
1754                 *p++ = 'L';
1755         if (gl->gl_object)
1756                 *p++ = 'o';
1757         if (test_bit(GLF_BLOCKING, gflags))
1758                 *p++ = 'b';
1759         *p = 0;
1760         return buf;
1761 }
1762 
1763 /**
1764  * gfs2_dump_glock - print information about a glock
1765  * @seq: The seq_file struct
1766  * @gl: the glock
1767  *
1768  * The file format is as follows:
1769  * One line per object, capital letters are used to indicate objects
1770  * G = glock, I = Inode, R = rgrp, H = holder. Glocks are not indented,
1771  * other objects are indented by a single space and follow the glock to
1772  * which they are related. Fields are indicated by lower case letters
1773  * followed by a colon and the field value, except for strings which are in
1774  * [] so that its possible to see if they are composed of spaces for
1775  * example. The field's are n = number (id of the object), f = flags,
1776  * t = type, s = state, r = refcount, e = error, p = pid.
1777  *
1778  */
1779 
1780 void gfs2_dump_glock(struct seq_file *seq, const struct gfs2_glock *gl)
1781 {
1782         const struct gfs2_glock_operations *glops = gl->gl_ops;
1783         unsigned long long dtime;
1784         const struct gfs2_holder *gh;
1785         char gflags_buf[32];
1786 
1787         dtime = jiffies - gl->gl_demote_time;
1788         dtime *= 1000000/HZ; /* demote time in uSec */
1789         if (!test_bit(GLF_DEMOTE, &gl->gl_flags))
1790                 dtime = 0;
1791         gfs2_print_dbg(seq, "G:  s:%s n:%u/%llx f:%s t:%s d:%s/%llu a:%d v:%d r:%d m:%ld\n",
1792                   state2str(gl->gl_state),
1793                   gl->gl_name.ln_type,
1794                   (unsigned long long)gl->gl_name.ln_number,
1795                   gflags2str(gflags_buf, gl),
1796                   state2str(gl->gl_target),
1797                   state2str(gl->gl_demote_state), dtime,
1798                   atomic_read(&gl->gl_ail_count),
1799                   atomic_read(&gl->gl_revokes),
1800                   (int)gl->gl_lockref.count, gl->gl_hold_time);
1801 
1802         list_for_each_entry(gh, &gl->gl_holders, gh_list)
1803                 dump_holder(seq, gh);
1804 
1805         if (gl->gl_state != LM_ST_UNLOCKED && glops->go_dump)
1806                 glops->go_dump(seq, gl);
1807 }
1808 
1809 static int gfs2_glstats_seq_show(struct seq_file *seq, void *iter_ptr)
1810 {
1811         struct gfs2_glock *gl = iter_ptr;
1812 
1813         seq_printf(seq, "G: n:%u/%llx rtt:%llu/%llu rttb:%llu/%llu irt:%llu/%llu dcnt: %llu qcnt: %llu\n",
1814                    gl->gl_name.ln_type,
1815                    (unsigned long long)gl->gl_name.ln_number,
1816                    (unsigned long long)gl->gl_stats.stats[GFS2_LKS_SRTT],
1817                    (unsigned long long)gl->gl_stats.stats[GFS2_LKS_SRTTVAR],
1818                    (unsigned long long)gl->gl_stats.stats[GFS2_LKS_SRTTB],
1819                    (unsigned long long)gl->gl_stats.stats[GFS2_LKS_SRTTVARB],
1820                    (unsigned long long)gl->gl_stats.stats[GFS2_LKS_SIRT],
1821                    (unsigned long long)gl->gl_stats.stats[GFS2_LKS_SIRTVAR],
1822                    (unsigned long long)gl->gl_stats.stats[GFS2_LKS_DCOUNT],
1823                    (unsigned long long)gl->gl_stats.stats[GFS2_LKS_QCOUNT]);
1824         return 0;
1825 }
1826 
1827 static const char *gfs2_gltype[] = {
1828         "type",
1829         "reserved",
1830         "nondisk",
1831         "inode",
1832         "rgrp",
1833         "meta",
1834         "iopen",
1835         "flock",
1836         "plock",
1837         "quota",
1838         "journal",
1839 };
1840 
1841 static const char *gfs2_stype[] = {
1842         [GFS2_LKS_SRTT]         = "srtt",
1843         [GFS2_LKS_SRTTVAR]      = "srttvar",
1844         [GFS2_LKS_SRTTB]        = "srttb",
1845         [GFS2_LKS_SRTTVARB]     = "srttvarb",
1846         [GFS2_LKS_SIRT]         = "sirt",
1847         [GFS2_LKS_SIRTVAR]      = "sirtvar",
1848         [GFS2_LKS_DCOUNT]       = "dlm",
1849         [GFS2_LKS_QCOUNT]       = "queue",
1850 };
1851 
1852 #define GFS2_NR_SBSTATS (ARRAY_SIZE(gfs2_gltype) * ARRAY_SIZE(gfs2_stype))
1853 
1854 static int gfs2_sbstats_seq_show(struct seq_file *seq, void *iter_ptr)
1855 {
1856         struct gfs2_sbd *sdp = seq->private;
1857         loff_t pos = *(loff_t *)iter_ptr;
1858         unsigned index = pos >> 3;
1859         unsigned subindex = pos & 0x07;
1860         int i;
1861 
1862         if (index == 0 && subindex != 0)
1863                 return 0;
1864 
1865         seq_printf(seq, "%-10s %8s:", gfs2_gltype[index],
1866                    (index == 0) ? "cpu": gfs2_stype[subindex]);
1867 
1868         for_each_possible_cpu(i) {
1869                 const struct gfs2_pcpu_lkstats *lkstats = per_cpu_ptr(sdp->sd_lkstats, i);
1870 
1871                 if (index == 0)
1872                         seq_printf(seq, " %15u", i);
1873                 else
1874                         seq_printf(seq, " %15llu", (unsigned long long)lkstats->
1875                                    lkstats[index - 1].stats[subindex]);
1876         }
1877         seq_putc(seq, '\n');
1878         return 0;
1879 }
1880 
1881 int __init gfs2_glock_init(void)
1882 {
1883         int i, ret;
1884 
1885         ret = rhashtable_init(&gl_hash_table, &ht_parms);
1886         if (ret < 0)
1887                 return ret;
1888 
1889         glock_workqueue = alloc_workqueue("glock_workqueue", WQ_MEM_RECLAIM |
1890                                           WQ_HIGHPRI | WQ_FREEZABLE, 0);
1891         if (!glock_workqueue) {
1892                 rhashtable_destroy(&gl_hash_table);
1893                 return -ENOMEM;
1894         }
1895         gfs2_delete_workqueue = alloc_workqueue("delete_workqueue",
1896                                                 WQ_MEM_RECLAIM | WQ_FREEZABLE,
1897                                                 0);
1898         if (!gfs2_delete_workqueue) {
1899                 destroy_workqueue(glock_workqueue);
1900                 rhashtable_destroy(&gl_hash_table);
1901                 return -ENOMEM;
1902         }
1903 
1904         ret = register_shrinker(&glock_shrinker);
1905         if (ret) {
1906                 destroy_workqueue(gfs2_delete_workqueue);
1907                 destroy_workqueue(glock_workqueue);
1908                 rhashtable_destroy(&gl_hash_table);
1909                 return ret;
1910         }
1911 
1912         for (i = 0; i < GLOCK_WAIT_TABLE_SIZE; i++)
1913                 init_waitqueue_head(glock_wait_table + i);
1914 
1915         return 0;
1916 }
1917 
1918 void gfs2_glock_exit(void)
1919 {
1920         unregister_shrinker(&glock_shrinker);
1921         rhashtable_destroy(&gl_hash_table);
1922         destroy_workqueue(glock_workqueue);
1923         destroy_workqueue(gfs2_delete_workqueue);
1924 }
1925 
1926 static void gfs2_glock_iter_next(struct gfs2_glock_iter *gi, loff_t n)
1927 {
1928         struct gfs2_glock *gl = gi->gl;
1929 
1930         if (gl) {
1931                 if (n == 0)
1932                         return;
1933                 if (!lockref_put_not_zero(&gl->gl_lockref))
1934                         gfs2_glock_queue_put(gl);
1935         }
1936         for (;;) {
1937                 gl = rhashtable_walk_next(&gi->hti);
1938                 if (IS_ERR_OR_NULL(gl)) {
1939                         if (gl == ERR_PTR(-EAGAIN)) {
1940                                 n = 1;
1941                                 continue;
1942                         }
1943                         gl = NULL;
1944                         break;
1945                 }
1946                 if (gl->gl_name.ln_sbd != gi->sdp)
1947                         continue;
1948                 if (n <= 1) {
1949                         if (!lockref_get_not_dead(&gl->gl_lockref))
1950                                 continue;
1951                         break;
1952                 } else {
1953                         if (__lockref_is_dead(&gl->gl_lockref))
1954                                 continue;
1955                         n--;
1956                 }
1957         }
1958         gi->gl = gl;
1959 }
1960 
1961 static void *gfs2_glock_seq_start(struct seq_file *seq, loff_t *pos)
1962         __acquires(RCU)
1963 {
1964         struct gfs2_glock_iter *gi = seq->private;
1965         loff_t n;
1966 
1967         /*
1968          * We can either stay where we are, skip to the next hash table
1969          * entry, or start from the beginning.
1970          */
1971         if (*pos < gi->last_pos) {
1972                 rhashtable_walk_exit(&gi->hti);
1973                 rhashtable_walk_enter(&gl_hash_table, &gi->hti);
1974                 n = *pos + 1;
1975         } else {
1976                 n = *pos - gi->last_pos;
1977         }
1978 
1979         rhashtable_walk_start(&gi->hti);
1980 
1981         gfs2_glock_iter_next(gi, n);
1982         gi->last_pos = *pos;
1983         return gi->gl;
1984 }
1985 
1986 static void *gfs2_glock_seq_next(struct seq_file *seq, void *iter_ptr,
1987                                  loff_t *pos)
1988 {
1989         struct gfs2_glock_iter *gi = seq->private;
1990 
1991         (*pos)++;
1992         gi->last_pos = *pos;
1993         gfs2_glock_iter_next(gi, 1);
1994         return gi->gl;
1995 }
1996 
1997 static void gfs2_glock_seq_stop(struct seq_file *seq, void *iter_ptr)
1998         __releases(RCU)
1999 {
2000         struct gfs2_glock_iter *gi = seq->private;
2001 
2002         rhashtable_walk_stop(&gi->hti);
2003 }
2004 
2005 static int gfs2_glock_seq_show(struct seq_file *seq, void *iter_ptr)
2006 {
2007         dump_glock(seq, iter_ptr);
2008         return 0;
2009 }
2010 
2011 static void *gfs2_sbstats_seq_start(struct seq_file *seq, loff_t *pos)
2012 {
2013         preempt_disable();
2014         if (*pos >= GFS2_NR_SBSTATS)
2015                 return NULL;
2016         return pos;
2017 }
2018 
2019 static void *gfs2_sbstats_seq_next(struct seq_file *seq, void *iter_ptr,
2020                                    loff_t *pos)
2021 {
2022         (*pos)++;
2023         if (*pos >= GFS2_NR_SBSTATS)
2024                 return NULL;
2025         return pos;
2026 }
2027 
2028 static void gfs2_sbstats_seq_stop(struct seq_file *seq, void *iter_ptr)
2029 {
2030         preempt_enable();
2031 }
2032 
2033 static const struct seq_operations gfs2_glock_seq_ops = {
2034         .start = gfs2_glock_seq_start,
2035         .next  = gfs2_glock_seq_next,
2036         .stop  = gfs2_glock_seq_stop,
2037         .show  = gfs2_glock_seq_show,
2038 };
2039 
2040 static const struct seq_operations gfs2_glstats_seq_ops = {
2041         .start = gfs2_glock_seq_start,
2042         .next  = gfs2_glock_seq_next,
2043         .stop  = gfs2_glock_seq_stop,
2044         .show  = gfs2_glstats_seq_show,
2045 };
2046 
2047 static const struct seq_operations gfs2_sbstats_seq_ops = {
2048         .start = gfs2_sbstats_seq_start,
2049         .next  = gfs2_sbstats_seq_next,
2050         .stop  = gfs2_sbstats_seq_stop,
2051         .show  = gfs2_sbstats_seq_show,
2052 };
2053 
2054 #define GFS2_SEQ_GOODSIZE min(PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER, 65536UL)
2055 
2056 static int __gfs2_glocks_open(struct inode *inode, struct file *file,
2057                               const struct seq_operations *ops)
2058 {
2059         int ret = seq_open_private(file, ops, sizeof(struct gfs2_glock_iter));
2060         if (ret == 0) {
2061                 struct seq_file *seq = file->private_data;
2062                 struct gfs2_glock_iter *gi = seq->private;
2063 
2064                 gi->sdp = inode->i_private;
2065                 seq->buf = kmalloc(GFS2_SEQ_GOODSIZE, GFP_KERNEL | __GFP_NOWARN);
2066                 if (seq->buf)
2067                         seq->size = GFS2_SEQ_GOODSIZE;
2068                 /*
2069                  * Initially, we are "before" the first hash table entry; the
2070                  * first call to rhashtable_walk_next gets us the first entry.
2071                  */
2072                 gi->last_pos = -1;
2073                 gi->gl = NULL;
2074                 rhashtable_walk_enter(&gl_hash_table, &gi->hti);
2075         }
2076         return ret;
2077 }
2078 
2079 static int gfs2_glocks_open(struct inode *inode, struct file *file)
2080 {
2081         return __gfs2_glocks_open(inode, file, &gfs2_glock_seq_ops);
2082 }
2083 
2084 static int gfs2_glocks_release(struct inode *inode, struct file *file)
2085 {
2086         struct seq_file *seq = file->private_data;
2087         struct gfs2_glock_iter *gi = seq->private;
2088 
2089         if (gi->gl)
2090                 gfs2_glock_put(gi->gl);
2091         rhashtable_walk_exit(&gi->hti);
2092         return seq_release_private(inode, file);
2093 }
2094 
2095 static int gfs2_glstats_open(struct inode *inode, struct file *file)
2096 {
2097         return __gfs2_glocks_open(inode, file, &gfs2_glstats_seq_ops);
2098 }
2099 
2100 static int gfs2_sbstats_open(struct inode *inode, struct file *file)
2101 {
2102         int ret = seq_open(file, &gfs2_sbstats_seq_ops);
2103         if (ret == 0) {
2104                 struct seq_file *seq = file->private_data;
2105                 seq->private = inode->i_private;  /* sdp */
2106         }
2107         return ret;
2108 }
2109 
2110 static const struct file_operations gfs2_glocks_fops = {
2111         .owner   = THIS_MODULE,
2112         .open    = gfs2_glocks_open,
2113         .read    = seq_read,
2114         .llseek  = seq_lseek,
2115         .release = gfs2_glocks_release,
2116 };
2117 
2118 static const struct file_operations gfs2_glstats_fops = {
2119         .owner   = THIS_MODULE,
2120         .open    = gfs2_glstats_open,
2121         .read    = seq_read,
2122         .llseek  = seq_lseek,
2123         .release = gfs2_glocks_release,
2124 };
2125 
2126 static const struct file_operations gfs2_sbstats_fops = {
2127         .owner   = THIS_MODULE,
2128         .open    = gfs2_sbstats_open,
2129         .read    = seq_read,
2130         .llseek  = seq_lseek,
2131         .release = seq_release,
2132 };
2133 
2134 int gfs2_create_debugfs_file(struct gfs2_sbd *sdp)
2135 {
2136         struct dentry *dent;
2137 
2138         dent = debugfs_create_dir(sdp->sd_table_name, gfs2_root);
2139         if (IS_ERR_OR_NULL(dent))
2140                 goto fail;
2141         sdp->debugfs_dir = dent;
2142 
2143         dent = debugfs_create_file("glocks",
2144                                    S_IFREG | S_IRUGO,
2145                                    sdp->debugfs_dir, sdp,
2146                                    &gfs2_glocks_fops);
2147         if (IS_ERR_OR_NULL(dent))
2148                 goto fail;
2149         sdp->debugfs_dentry_glocks = dent;
2150 
2151         dent = debugfs_create_file("glstats",
2152                                    S_IFREG | S_IRUGO,
2153                                    sdp->debugfs_dir, sdp,
2154                                    &gfs2_glstats_fops);
2155         if (IS_ERR_OR_NULL(dent))
2156                 goto fail;
2157         sdp->debugfs_dentry_glstats = dent;
2158 
2159         dent = debugfs_create_file("sbstats",
2160                                    S_IFREG | S_IRUGO,
2161                                    sdp->debugfs_dir, sdp,
2162                                    &gfs2_sbstats_fops);
2163         if (IS_ERR_OR_NULL(dent))
2164                 goto fail;
2165         sdp->debugfs_dentry_sbstats = dent;
2166 
2167         return 0;
2168 fail:
2169         gfs2_delete_debugfs_file(sdp);
2170         return dent ? PTR_ERR(dent) : -ENOMEM;
2171 }
2172 
2173 void gfs2_delete_debugfs_file(struct gfs2_sbd *sdp)
2174 {
2175         if (sdp->debugfs_dir) {
2176                 if (sdp->debugfs_dentry_glocks) {
2177                         debugfs_remove(sdp->debugfs_dentry_glocks);
2178                         sdp->debugfs_dentry_glocks = NULL;
2179                 }
2180                 if (sdp->debugfs_dentry_glstats) {
2181                         debugfs_remove(sdp->debugfs_dentry_glstats);
2182                         sdp->debugfs_dentry_glstats = NULL;
2183                 }
2184                 if (sdp->debugfs_dentry_sbstats) {
2185                         debugfs_remove(sdp->debugfs_dentry_sbstats);
2186                         sdp->debugfs_dentry_sbstats = NULL;
2187                 }
2188                 debugfs_remove(sdp->debugfs_dir);
2189                 sdp->debugfs_dir = NULL;
2190         }
2191 }
2192 
2193 int gfs2_register_debugfs(void)
2194 {
2195         gfs2_root = debugfs_create_dir("gfs2", NULL);
2196         if (IS_ERR(gfs2_root))
2197                 return PTR_ERR(gfs2_root);
2198         return gfs2_root ? 0 : -ENOMEM;
2199 }
2200 
2201 void gfs2_unregister_debugfs(void)
2202 {
2203         debugfs_remove(gfs2_root);
2204         gfs2_root = NULL;
2205 }
2206 

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