~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

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

Version: ~ [ linux-5.6-rc3 ] ~ [ linux-5.5.6 ] ~ [ linux-5.4.22 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.106 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.171 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.214 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.214 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.140 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.82 ] ~ [ 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-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

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

~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

kernel.org | git.kernel.org | LWN.net | Project Home | Wiki (Japanese) | Wiki (English) | SVN repository | Mail admin

Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.

osdn.jp