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TOMOYO Linux Cross Reference
Linux/fs/ocfs2/dlmglue.c

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  1 /* -*- mode: c; c-basic-offset: 8; -*-
  2  * vim: noexpandtab sw=8 ts=8 sts=0:
  3  *
  4  * dlmglue.c
  5  *
  6  * Code which implements an OCFS2 specific interface to our DLM.
  7  *
  8  * Copyright (C) 2003, 2004 Oracle.  All rights reserved.
  9  *
 10  * This program is free software; you can redistribute it and/or
 11  * modify it under the terms of the GNU General Public
 12  * License as published by the Free Software Foundation; either
 13  * version 2 of the License, or (at your option) any later version.
 14  *
 15  * This program is distributed in the hope that it will be useful,
 16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
 17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 18  * General Public License for more details.
 19  *
 20  * You should have received a copy of the GNU General Public
 21  * License along with this program; if not, write to the
 22  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 23  * Boston, MA 021110-1307, USA.
 24  */
 25 
 26 #include <linux/types.h>
 27 #include <linux/slab.h>
 28 #include <linux/highmem.h>
 29 #include <linux/mm.h>
 30 #include <linux/kthread.h>
 31 #include <linux/pagemap.h>
 32 #include <linux/debugfs.h>
 33 #include <linux/seq_file.h>
 34 #include <linux/time.h>
 35 #include <linux/quotaops.h>
 36 #include <linux/sched/signal.h>
 37 
 38 #define MLOG_MASK_PREFIX ML_DLM_GLUE
 39 #include <cluster/masklog.h>
 40 
 41 #include "ocfs2.h"
 42 #include "ocfs2_lockingver.h"
 43 
 44 #include "alloc.h"
 45 #include "dcache.h"
 46 #include "dlmglue.h"
 47 #include "extent_map.h"
 48 #include "file.h"
 49 #include "heartbeat.h"
 50 #include "inode.h"
 51 #include "journal.h"
 52 #include "stackglue.h"
 53 #include "slot_map.h"
 54 #include "super.h"
 55 #include "uptodate.h"
 56 #include "quota.h"
 57 #include "refcounttree.h"
 58 #include "acl.h"
 59 
 60 #include "buffer_head_io.h"
 61 
 62 struct ocfs2_mask_waiter {
 63         struct list_head        mw_item;
 64         int                     mw_status;
 65         struct completion       mw_complete;
 66         unsigned long           mw_mask;
 67         unsigned long           mw_goal;
 68 #ifdef CONFIG_OCFS2_FS_STATS
 69         ktime_t                 mw_lock_start;
 70 #endif
 71 };
 72 
 73 static struct ocfs2_super *ocfs2_get_dentry_osb(struct ocfs2_lock_res *lockres);
 74 static struct ocfs2_super *ocfs2_get_inode_osb(struct ocfs2_lock_res *lockres);
 75 static struct ocfs2_super *ocfs2_get_file_osb(struct ocfs2_lock_res *lockres);
 76 static struct ocfs2_super *ocfs2_get_qinfo_osb(struct ocfs2_lock_res *lockres);
 77 
 78 /*
 79  * Return value from ->downconvert_worker functions.
 80  *
 81  * These control the precise actions of ocfs2_unblock_lock()
 82  * and ocfs2_process_blocked_lock()
 83  *
 84  */
 85 enum ocfs2_unblock_action {
 86         UNBLOCK_CONTINUE        = 0, /* Continue downconvert */
 87         UNBLOCK_CONTINUE_POST   = 1, /* Continue downconvert, fire
 88                                       * ->post_unlock callback */
 89         UNBLOCK_STOP_POST       = 2, /* Do not downconvert, fire
 90                                       * ->post_unlock() callback. */
 91 };
 92 
 93 struct ocfs2_unblock_ctl {
 94         int requeue;
 95         enum ocfs2_unblock_action unblock_action;
 96 };
 97 
 98 /* Lockdep class keys */
 99 #ifdef CONFIG_DEBUG_LOCK_ALLOC
100 static struct lock_class_key lockdep_keys[OCFS2_NUM_LOCK_TYPES];
101 #endif
102 
103 static int ocfs2_check_meta_downconvert(struct ocfs2_lock_res *lockres,
104                                         int new_level);
105 static void ocfs2_set_meta_lvb(struct ocfs2_lock_res *lockres);
106 
107 static int ocfs2_data_convert_worker(struct ocfs2_lock_res *lockres,
108                                      int blocking);
109 
110 static int ocfs2_dentry_convert_worker(struct ocfs2_lock_res *lockres,
111                                        int blocking);
112 
113 static void ocfs2_dentry_post_unlock(struct ocfs2_super *osb,
114                                      struct ocfs2_lock_res *lockres);
115 
116 static void ocfs2_set_qinfo_lvb(struct ocfs2_lock_res *lockres);
117 
118 static int ocfs2_check_refcount_downconvert(struct ocfs2_lock_res *lockres,
119                                             int new_level);
120 static int ocfs2_refcount_convert_worker(struct ocfs2_lock_res *lockres,
121                                          int blocking);
122 
123 #define mlog_meta_lvb(__level, __lockres) ocfs2_dump_meta_lvb_info(__level, __PRETTY_FUNCTION__, __LINE__, __lockres)
124 
125 /* This aids in debugging situations where a bad LVB might be involved. */
126 static void ocfs2_dump_meta_lvb_info(u64 level,
127                                      const char *function,
128                                      unsigned int line,
129                                      struct ocfs2_lock_res *lockres)
130 {
131         struct ocfs2_meta_lvb *lvb = ocfs2_dlm_lvb(&lockres->l_lksb);
132 
133         mlog(level, "LVB information for %s (called from %s:%u):\n",
134              lockres->l_name, function, line);
135         mlog(level, "version: %u, clusters: %u, generation: 0x%x\n",
136              lvb->lvb_version, be32_to_cpu(lvb->lvb_iclusters),
137              be32_to_cpu(lvb->lvb_igeneration));
138         mlog(level, "size: %llu, uid %u, gid %u, mode 0x%x\n",
139              (unsigned long long)be64_to_cpu(lvb->lvb_isize),
140              be32_to_cpu(lvb->lvb_iuid), be32_to_cpu(lvb->lvb_igid),
141              be16_to_cpu(lvb->lvb_imode));
142         mlog(level, "nlink %u, atime_packed 0x%llx, ctime_packed 0x%llx, "
143              "mtime_packed 0x%llx iattr 0x%x\n", be16_to_cpu(lvb->lvb_inlink),
144              (long long)be64_to_cpu(lvb->lvb_iatime_packed),
145              (long long)be64_to_cpu(lvb->lvb_ictime_packed),
146              (long long)be64_to_cpu(lvb->lvb_imtime_packed),
147              be32_to_cpu(lvb->lvb_iattr));
148 }
149 
150 
151 /*
152  * OCFS2 Lock Resource Operations
153  *
154  * These fine tune the behavior of the generic dlmglue locking infrastructure.
155  *
156  * The most basic of lock types can point ->l_priv to their respective
157  * struct ocfs2_super and allow the default actions to manage things.
158  *
159  * Right now, each lock type also needs to implement an init function,
160  * and trivial lock/unlock wrappers. ocfs2_simple_drop_lockres()
161  * should be called when the lock is no longer needed (i.e., object
162  * destruction time).
163  */
164 struct ocfs2_lock_res_ops {
165         /*
166          * Translate an ocfs2_lock_res * into an ocfs2_super *. Define
167          * this callback if ->l_priv is not an ocfs2_super pointer
168          */
169         struct ocfs2_super * (*get_osb)(struct ocfs2_lock_res *);
170 
171         /*
172          * Optionally called in the downconvert thread after a
173          * successful downconvert. The lockres will not be referenced
174          * after this callback is called, so it is safe to free
175          * memory, etc.
176          *
177          * The exact semantics of when this is called are controlled
178          * by ->downconvert_worker()
179          */
180         void (*post_unlock)(struct ocfs2_super *, struct ocfs2_lock_res *);
181 
182         /*
183          * Allow a lock type to add checks to determine whether it is
184          * safe to downconvert a lock. Return 0 to re-queue the
185          * downconvert at a later time, nonzero to continue.
186          *
187          * For most locks, the default checks that there are no
188          * incompatible holders are sufficient.
189          *
190          * Called with the lockres spinlock held.
191          */
192         int (*check_downconvert)(struct ocfs2_lock_res *, int);
193 
194         /*
195          * Allows a lock type to populate the lock value block. This
196          * is called on downconvert, and when we drop a lock.
197          *
198          * Locks that want to use this should set LOCK_TYPE_USES_LVB
199          * in the flags field.
200          *
201          * Called with the lockres spinlock held.
202          */
203         void (*set_lvb)(struct ocfs2_lock_res *);
204 
205         /*
206          * Called from the downconvert thread when it is determined
207          * that a lock will be downconverted. This is called without
208          * any locks held so the function can do work that might
209          * schedule (syncing out data, etc).
210          *
211          * This should return any one of the ocfs2_unblock_action
212          * values, depending on what it wants the thread to do.
213          */
214         int (*downconvert_worker)(struct ocfs2_lock_res *, int);
215 
216         /*
217          * LOCK_TYPE_* flags which describe the specific requirements
218          * of a lock type. Descriptions of each individual flag follow.
219          */
220         int flags;
221 };
222 
223 /*
224  * Some locks want to "refresh" potentially stale data when a
225  * meaningful (PRMODE or EXMODE) lock level is first obtained. If this
226  * flag is set, the OCFS2_LOCK_NEEDS_REFRESH flag will be set on the
227  * individual lockres l_flags member from the ast function. It is
228  * expected that the locking wrapper will clear the
229  * OCFS2_LOCK_NEEDS_REFRESH flag when done.
230  */
231 #define LOCK_TYPE_REQUIRES_REFRESH 0x1
232 
233 /*
234  * Indicate that a lock type makes use of the lock value block. The
235  * ->set_lvb lock type callback must be defined.
236  */
237 #define LOCK_TYPE_USES_LVB              0x2
238 
239 static struct ocfs2_lock_res_ops ocfs2_inode_rw_lops = {
240         .get_osb        = ocfs2_get_inode_osb,
241         .flags          = 0,
242 };
243 
244 static struct ocfs2_lock_res_ops ocfs2_inode_inode_lops = {
245         .get_osb        = ocfs2_get_inode_osb,
246         .check_downconvert = ocfs2_check_meta_downconvert,
247         .set_lvb        = ocfs2_set_meta_lvb,
248         .downconvert_worker = ocfs2_data_convert_worker,
249         .flags          = LOCK_TYPE_REQUIRES_REFRESH|LOCK_TYPE_USES_LVB,
250 };
251 
252 static struct ocfs2_lock_res_ops ocfs2_super_lops = {
253         .flags          = LOCK_TYPE_REQUIRES_REFRESH,
254 };
255 
256 static struct ocfs2_lock_res_ops ocfs2_rename_lops = {
257         .flags          = 0,
258 };
259 
260 static struct ocfs2_lock_res_ops ocfs2_nfs_sync_lops = {
261         .flags          = 0,
262 };
263 
264 static struct ocfs2_lock_res_ops ocfs2_trim_fs_lops = {
265         .flags          = LOCK_TYPE_REQUIRES_REFRESH|LOCK_TYPE_USES_LVB,
266 };
267 
268 static struct ocfs2_lock_res_ops ocfs2_orphan_scan_lops = {
269         .flags          = LOCK_TYPE_REQUIRES_REFRESH|LOCK_TYPE_USES_LVB,
270 };
271 
272 static struct ocfs2_lock_res_ops ocfs2_dentry_lops = {
273         .get_osb        = ocfs2_get_dentry_osb,
274         .post_unlock    = ocfs2_dentry_post_unlock,
275         .downconvert_worker = ocfs2_dentry_convert_worker,
276         .flags          = 0,
277 };
278 
279 static struct ocfs2_lock_res_ops ocfs2_inode_open_lops = {
280         .get_osb        = ocfs2_get_inode_osb,
281         .flags          = 0,
282 };
283 
284 static struct ocfs2_lock_res_ops ocfs2_flock_lops = {
285         .get_osb        = ocfs2_get_file_osb,
286         .flags          = 0,
287 };
288 
289 static struct ocfs2_lock_res_ops ocfs2_qinfo_lops = {
290         .set_lvb        = ocfs2_set_qinfo_lvb,
291         .get_osb        = ocfs2_get_qinfo_osb,
292         .flags          = LOCK_TYPE_REQUIRES_REFRESH | LOCK_TYPE_USES_LVB,
293 };
294 
295 static struct ocfs2_lock_res_ops ocfs2_refcount_block_lops = {
296         .check_downconvert = ocfs2_check_refcount_downconvert,
297         .downconvert_worker = ocfs2_refcount_convert_worker,
298         .flags          = 0,
299 };
300 
301 static inline int ocfs2_is_inode_lock(struct ocfs2_lock_res *lockres)
302 {
303         return lockres->l_type == OCFS2_LOCK_TYPE_META ||
304                 lockres->l_type == OCFS2_LOCK_TYPE_RW ||
305                 lockres->l_type == OCFS2_LOCK_TYPE_OPEN;
306 }
307 
308 static inline struct ocfs2_lock_res *ocfs2_lksb_to_lock_res(struct ocfs2_dlm_lksb *lksb)
309 {
310         return container_of(lksb, struct ocfs2_lock_res, l_lksb);
311 }
312 
313 static inline struct inode *ocfs2_lock_res_inode(struct ocfs2_lock_res *lockres)
314 {
315         BUG_ON(!ocfs2_is_inode_lock(lockres));
316 
317         return (struct inode *) lockres->l_priv;
318 }
319 
320 static inline struct ocfs2_dentry_lock *ocfs2_lock_res_dl(struct ocfs2_lock_res *lockres)
321 {
322         BUG_ON(lockres->l_type != OCFS2_LOCK_TYPE_DENTRY);
323 
324         return (struct ocfs2_dentry_lock *)lockres->l_priv;
325 }
326 
327 static inline struct ocfs2_mem_dqinfo *ocfs2_lock_res_qinfo(struct ocfs2_lock_res *lockres)
328 {
329         BUG_ON(lockres->l_type != OCFS2_LOCK_TYPE_QINFO);
330 
331         return (struct ocfs2_mem_dqinfo *)lockres->l_priv;
332 }
333 
334 static inline struct ocfs2_refcount_tree *
335 ocfs2_lock_res_refcount_tree(struct ocfs2_lock_res *res)
336 {
337         return container_of(res, struct ocfs2_refcount_tree, rf_lockres);
338 }
339 
340 static inline struct ocfs2_super *ocfs2_get_lockres_osb(struct ocfs2_lock_res *lockres)
341 {
342         if (lockres->l_ops->get_osb)
343                 return lockres->l_ops->get_osb(lockres);
344 
345         return (struct ocfs2_super *)lockres->l_priv;
346 }
347 
348 static int ocfs2_lock_create(struct ocfs2_super *osb,
349                              struct ocfs2_lock_res *lockres,
350                              int level,
351                              u32 dlm_flags);
352 static inline int ocfs2_may_continue_on_blocked_lock(struct ocfs2_lock_res *lockres,
353                                                      int wanted);
354 static void __ocfs2_cluster_unlock(struct ocfs2_super *osb,
355                                    struct ocfs2_lock_res *lockres,
356                                    int level, unsigned long caller_ip);
357 static inline void ocfs2_cluster_unlock(struct ocfs2_super *osb,
358                                         struct ocfs2_lock_res *lockres,
359                                         int level)
360 {
361         __ocfs2_cluster_unlock(osb, lockres, level, _RET_IP_);
362 }
363 
364 static inline void ocfs2_generic_handle_downconvert_action(struct ocfs2_lock_res *lockres);
365 static inline void ocfs2_generic_handle_convert_action(struct ocfs2_lock_res *lockres);
366 static inline void ocfs2_generic_handle_attach_action(struct ocfs2_lock_res *lockres);
367 static int ocfs2_generic_handle_bast(struct ocfs2_lock_res *lockres, int level);
368 static void ocfs2_schedule_blocked_lock(struct ocfs2_super *osb,
369                                         struct ocfs2_lock_res *lockres);
370 static inline void ocfs2_recover_from_dlm_error(struct ocfs2_lock_res *lockres,
371                                                 int convert);
372 #define ocfs2_log_dlm_error(_func, _err, _lockres) do {                                 \
373         if ((_lockres)->l_type != OCFS2_LOCK_TYPE_DENTRY)                               \
374                 mlog(ML_ERROR, "DLM error %d while calling %s on resource %s\n",        \
375                      _err, _func, _lockres->l_name);                                    \
376         else                                                                            \
377                 mlog(ML_ERROR, "DLM error %d while calling %s on resource %.*s%08x\n",  \
378                      _err, _func, OCFS2_DENTRY_LOCK_INO_START - 1, (_lockres)->l_name,  \
379                      (unsigned int)ocfs2_get_dentry_lock_ino(_lockres));                \
380 } while (0)
381 static int ocfs2_downconvert_thread(void *arg);
382 static void ocfs2_downconvert_on_unlock(struct ocfs2_super *osb,
383                                         struct ocfs2_lock_res *lockres);
384 static int ocfs2_inode_lock_update(struct inode *inode,
385                                   struct buffer_head **bh);
386 static void ocfs2_drop_osb_locks(struct ocfs2_super *osb);
387 static inline int ocfs2_highest_compat_lock_level(int level);
388 static unsigned int ocfs2_prepare_downconvert(struct ocfs2_lock_res *lockres,
389                                               int new_level);
390 static int ocfs2_downconvert_lock(struct ocfs2_super *osb,
391                                   struct ocfs2_lock_res *lockres,
392                                   int new_level,
393                                   int lvb,
394                                   unsigned int generation);
395 static int ocfs2_prepare_cancel_convert(struct ocfs2_super *osb,
396                                         struct ocfs2_lock_res *lockres);
397 static int ocfs2_cancel_convert(struct ocfs2_super *osb,
398                                 struct ocfs2_lock_res *lockres);
399 
400 
401 static void ocfs2_build_lock_name(enum ocfs2_lock_type type,
402                                   u64 blkno,
403                                   u32 generation,
404                                   char *name)
405 {
406         int len;
407 
408         BUG_ON(type >= OCFS2_NUM_LOCK_TYPES);
409 
410         len = snprintf(name, OCFS2_LOCK_ID_MAX_LEN, "%c%s%016llx%08x",
411                        ocfs2_lock_type_char(type), OCFS2_LOCK_ID_PAD,
412                        (long long)blkno, generation);
413 
414         BUG_ON(len != (OCFS2_LOCK_ID_MAX_LEN - 1));
415 
416         mlog(0, "built lock resource with name: %s\n", name);
417 }
418 
419 static DEFINE_SPINLOCK(ocfs2_dlm_tracking_lock);
420 
421 static void ocfs2_add_lockres_tracking(struct ocfs2_lock_res *res,
422                                        struct ocfs2_dlm_debug *dlm_debug)
423 {
424         mlog(0, "Add tracking for lockres %s\n", res->l_name);
425 
426         spin_lock(&ocfs2_dlm_tracking_lock);
427         list_add(&res->l_debug_list, &dlm_debug->d_lockres_tracking);
428         spin_unlock(&ocfs2_dlm_tracking_lock);
429 }
430 
431 static void ocfs2_remove_lockres_tracking(struct ocfs2_lock_res *res)
432 {
433         spin_lock(&ocfs2_dlm_tracking_lock);
434         if (!list_empty(&res->l_debug_list))
435                 list_del_init(&res->l_debug_list);
436         spin_unlock(&ocfs2_dlm_tracking_lock);
437 }
438 
439 #ifdef CONFIG_OCFS2_FS_STATS
440 static void ocfs2_init_lock_stats(struct ocfs2_lock_res *res)
441 {
442         res->l_lock_refresh = 0;
443         memset(&res->l_lock_prmode, 0, sizeof(struct ocfs2_lock_stats));
444         memset(&res->l_lock_exmode, 0, sizeof(struct ocfs2_lock_stats));
445 }
446 
447 static void ocfs2_update_lock_stats(struct ocfs2_lock_res *res, int level,
448                                     struct ocfs2_mask_waiter *mw, int ret)
449 {
450         u32 usec;
451         ktime_t kt;
452         struct ocfs2_lock_stats *stats;
453 
454         if (level == LKM_PRMODE)
455                 stats = &res->l_lock_prmode;
456         else if (level == LKM_EXMODE)
457                 stats = &res->l_lock_exmode;
458         else
459                 return;
460 
461         kt = ktime_sub(ktime_get(), mw->mw_lock_start);
462         usec = ktime_to_us(kt);
463 
464         stats->ls_gets++;
465         stats->ls_total += ktime_to_ns(kt);
466         /* overflow */
467         if (unlikely(stats->ls_gets == 0)) {
468                 stats->ls_gets++;
469                 stats->ls_total = ktime_to_ns(kt);
470         }
471 
472         if (stats->ls_max < usec)
473                 stats->ls_max = usec;
474 
475         if (ret)
476                 stats->ls_fail++;
477 }
478 
479 static inline void ocfs2_track_lock_refresh(struct ocfs2_lock_res *lockres)
480 {
481         lockres->l_lock_refresh++;
482 }
483 
484 static inline void ocfs2_init_start_time(struct ocfs2_mask_waiter *mw)
485 {
486         mw->mw_lock_start = ktime_get();
487 }
488 #else
489 static inline void ocfs2_init_lock_stats(struct ocfs2_lock_res *res)
490 {
491 }
492 static inline void ocfs2_update_lock_stats(struct ocfs2_lock_res *res,
493                            int level, struct ocfs2_mask_waiter *mw, int ret)
494 {
495 }
496 static inline void ocfs2_track_lock_refresh(struct ocfs2_lock_res *lockres)
497 {
498 }
499 static inline void ocfs2_init_start_time(struct ocfs2_mask_waiter *mw)
500 {
501 }
502 #endif
503 
504 static void ocfs2_lock_res_init_common(struct ocfs2_super *osb,
505                                        struct ocfs2_lock_res *res,
506                                        enum ocfs2_lock_type type,
507                                        struct ocfs2_lock_res_ops *ops,
508                                        void *priv)
509 {
510         res->l_type          = type;
511         res->l_ops           = ops;
512         res->l_priv          = priv;
513 
514         res->l_level         = DLM_LOCK_IV;
515         res->l_requested     = DLM_LOCK_IV;
516         res->l_blocking      = DLM_LOCK_IV;
517         res->l_action        = OCFS2_AST_INVALID;
518         res->l_unlock_action = OCFS2_UNLOCK_INVALID;
519 
520         res->l_flags         = OCFS2_LOCK_INITIALIZED;
521 
522         ocfs2_add_lockres_tracking(res, osb->osb_dlm_debug);
523 
524         ocfs2_init_lock_stats(res);
525 #ifdef CONFIG_DEBUG_LOCK_ALLOC
526         if (type != OCFS2_LOCK_TYPE_OPEN)
527                 lockdep_init_map(&res->l_lockdep_map, ocfs2_lock_type_strings[type],
528                                  &lockdep_keys[type], 0);
529         else
530                 res->l_lockdep_map.key = NULL;
531 #endif
532 }
533 
534 void ocfs2_lock_res_init_once(struct ocfs2_lock_res *res)
535 {
536         /* This also clears out the lock status block */
537         memset(res, 0, sizeof(struct ocfs2_lock_res));
538         spin_lock_init(&res->l_lock);
539         init_waitqueue_head(&res->l_event);
540         INIT_LIST_HEAD(&res->l_blocked_list);
541         INIT_LIST_HEAD(&res->l_mask_waiters);
542         INIT_LIST_HEAD(&res->l_holders);
543 }
544 
545 void ocfs2_inode_lock_res_init(struct ocfs2_lock_res *res,
546                                enum ocfs2_lock_type type,
547                                unsigned int generation,
548                                struct inode *inode)
549 {
550         struct ocfs2_lock_res_ops *ops;
551 
552         switch(type) {
553                 case OCFS2_LOCK_TYPE_RW:
554                         ops = &ocfs2_inode_rw_lops;
555                         break;
556                 case OCFS2_LOCK_TYPE_META:
557                         ops = &ocfs2_inode_inode_lops;
558                         break;
559                 case OCFS2_LOCK_TYPE_OPEN:
560                         ops = &ocfs2_inode_open_lops;
561                         break;
562                 default:
563                         mlog_bug_on_msg(1, "type: %d\n", type);
564                         ops = NULL; /* thanks, gcc */
565                         break;
566         };
567 
568         ocfs2_build_lock_name(type, OCFS2_I(inode)->ip_blkno,
569                               generation, res->l_name);
570         ocfs2_lock_res_init_common(OCFS2_SB(inode->i_sb), res, type, ops, inode);
571 }
572 
573 static struct ocfs2_super *ocfs2_get_inode_osb(struct ocfs2_lock_res *lockres)
574 {
575         struct inode *inode = ocfs2_lock_res_inode(lockres);
576 
577         return OCFS2_SB(inode->i_sb);
578 }
579 
580 static struct ocfs2_super *ocfs2_get_qinfo_osb(struct ocfs2_lock_res *lockres)
581 {
582         struct ocfs2_mem_dqinfo *info = lockres->l_priv;
583 
584         return OCFS2_SB(info->dqi_gi.dqi_sb);
585 }
586 
587 static struct ocfs2_super *ocfs2_get_file_osb(struct ocfs2_lock_res *lockres)
588 {
589         struct ocfs2_file_private *fp = lockres->l_priv;
590 
591         return OCFS2_SB(fp->fp_file->f_mapping->host->i_sb);
592 }
593 
594 static __u64 ocfs2_get_dentry_lock_ino(struct ocfs2_lock_res *lockres)
595 {
596         __be64 inode_blkno_be;
597 
598         memcpy(&inode_blkno_be, &lockres->l_name[OCFS2_DENTRY_LOCK_INO_START],
599                sizeof(__be64));
600 
601         return be64_to_cpu(inode_blkno_be);
602 }
603 
604 static struct ocfs2_super *ocfs2_get_dentry_osb(struct ocfs2_lock_res *lockres)
605 {
606         struct ocfs2_dentry_lock *dl = lockres->l_priv;
607 
608         return OCFS2_SB(dl->dl_inode->i_sb);
609 }
610 
611 void ocfs2_dentry_lock_res_init(struct ocfs2_dentry_lock *dl,
612                                 u64 parent, struct inode *inode)
613 {
614         int len;
615         u64 inode_blkno = OCFS2_I(inode)->ip_blkno;
616         __be64 inode_blkno_be = cpu_to_be64(inode_blkno);
617         struct ocfs2_lock_res *lockres = &dl->dl_lockres;
618 
619         ocfs2_lock_res_init_once(lockres);
620 
621         /*
622          * Unfortunately, the standard lock naming scheme won't work
623          * here because we have two 16 byte values to use. Instead,
624          * we'll stuff the inode number as a binary value. We still
625          * want error prints to show something without garbling the
626          * display, so drop a null byte in there before the inode
627          * number. A future version of OCFS2 will likely use all
628          * binary lock names. The stringified names have been a
629          * tremendous aid in debugging, but now that the debugfs
630          * interface exists, we can mangle things there if need be.
631          *
632          * NOTE: We also drop the standard "pad" value (the total lock
633          * name size stays the same though - the last part is all
634          * zeros due to the memset in ocfs2_lock_res_init_once()
635          */
636         len = snprintf(lockres->l_name, OCFS2_DENTRY_LOCK_INO_START,
637                        "%c%016llx",
638                        ocfs2_lock_type_char(OCFS2_LOCK_TYPE_DENTRY),
639                        (long long)parent);
640 
641         BUG_ON(len != (OCFS2_DENTRY_LOCK_INO_START - 1));
642 
643         memcpy(&lockres->l_name[OCFS2_DENTRY_LOCK_INO_START], &inode_blkno_be,
644                sizeof(__be64));
645 
646         ocfs2_lock_res_init_common(OCFS2_SB(inode->i_sb), lockres,
647                                    OCFS2_LOCK_TYPE_DENTRY, &ocfs2_dentry_lops,
648                                    dl);
649 }
650 
651 static void ocfs2_super_lock_res_init(struct ocfs2_lock_res *res,
652                                       struct ocfs2_super *osb)
653 {
654         /* Superblock lockres doesn't come from a slab so we call init
655          * once on it manually.  */
656         ocfs2_lock_res_init_once(res);
657         ocfs2_build_lock_name(OCFS2_LOCK_TYPE_SUPER, OCFS2_SUPER_BLOCK_BLKNO,
658                               0, res->l_name);
659         ocfs2_lock_res_init_common(osb, res, OCFS2_LOCK_TYPE_SUPER,
660                                    &ocfs2_super_lops, osb);
661 }
662 
663 static void ocfs2_rename_lock_res_init(struct ocfs2_lock_res *res,
664                                        struct ocfs2_super *osb)
665 {
666         /* Rename lockres doesn't come from a slab so we call init
667          * once on it manually.  */
668         ocfs2_lock_res_init_once(res);
669         ocfs2_build_lock_name(OCFS2_LOCK_TYPE_RENAME, 0, 0, res->l_name);
670         ocfs2_lock_res_init_common(osb, res, OCFS2_LOCK_TYPE_RENAME,
671                                    &ocfs2_rename_lops, osb);
672 }
673 
674 static void ocfs2_nfs_sync_lock_res_init(struct ocfs2_lock_res *res,
675                                          struct ocfs2_super *osb)
676 {
677         /* nfs_sync lockres doesn't come from a slab so we call init
678          * once on it manually.  */
679         ocfs2_lock_res_init_once(res);
680         ocfs2_build_lock_name(OCFS2_LOCK_TYPE_NFS_SYNC, 0, 0, res->l_name);
681         ocfs2_lock_res_init_common(osb, res, OCFS2_LOCK_TYPE_NFS_SYNC,
682                                    &ocfs2_nfs_sync_lops, osb);
683 }
684 
685 void ocfs2_trim_fs_lock_res_init(struct ocfs2_super *osb)
686 {
687         struct ocfs2_lock_res *lockres = &osb->osb_trim_fs_lockres;
688 
689         ocfs2_lock_res_init_once(lockres);
690         ocfs2_build_lock_name(OCFS2_LOCK_TYPE_TRIM_FS, 0, 0, lockres->l_name);
691         ocfs2_lock_res_init_common(osb, lockres, OCFS2_LOCK_TYPE_TRIM_FS,
692                                    &ocfs2_trim_fs_lops, osb);
693 }
694 
695 void ocfs2_trim_fs_lock_res_uninit(struct ocfs2_super *osb)
696 {
697         struct ocfs2_lock_res *lockres = &osb->osb_trim_fs_lockres;
698 
699         ocfs2_simple_drop_lockres(osb, lockres);
700         ocfs2_lock_res_free(lockres);
701 }
702 
703 static void ocfs2_orphan_scan_lock_res_init(struct ocfs2_lock_res *res,
704                                             struct ocfs2_super *osb)
705 {
706         ocfs2_lock_res_init_once(res);
707         ocfs2_build_lock_name(OCFS2_LOCK_TYPE_ORPHAN_SCAN, 0, 0, res->l_name);
708         ocfs2_lock_res_init_common(osb, res, OCFS2_LOCK_TYPE_ORPHAN_SCAN,
709                                    &ocfs2_orphan_scan_lops, osb);
710 }
711 
712 void ocfs2_file_lock_res_init(struct ocfs2_lock_res *lockres,
713                               struct ocfs2_file_private *fp)
714 {
715         struct inode *inode = fp->fp_file->f_mapping->host;
716         struct ocfs2_inode_info *oi = OCFS2_I(inode);
717 
718         ocfs2_lock_res_init_once(lockres);
719         ocfs2_build_lock_name(OCFS2_LOCK_TYPE_FLOCK, oi->ip_blkno,
720                               inode->i_generation, lockres->l_name);
721         ocfs2_lock_res_init_common(OCFS2_SB(inode->i_sb), lockres,
722                                    OCFS2_LOCK_TYPE_FLOCK, &ocfs2_flock_lops,
723                                    fp);
724         lockres->l_flags |= OCFS2_LOCK_NOCACHE;
725 }
726 
727 void ocfs2_qinfo_lock_res_init(struct ocfs2_lock_res *lockres,
728                                struct ocfs2_mem_dqinfo *info)
729 {
730         ocfs2_lock_res_init_once(lockres);
731         ocfs2_build_lock_name(OCFS2_LOCK_TYPE_QINFO, info->dqi_gi.dqi_type,
732                               0, lockres->l_name);
733         ocfs2_lock_res_init_common(OCFS2_SB(info->dqi_gi.dqi_sb), lockres,
734                                    OCFS2_LOCK_TYPE_QINFO, &ocfs2_qinfo_lops,
735                                    info);
736 }
737 
738 void ocfs2_refcount_lock_res_init(struct ocfs2_lock_res *lockres,
739                                   struct ocfs2_super *osb, u64 ref_blkno,
740                                   unsigned int generation)
741 {
742         ocfs2_lock_res_init_once(lockres);
743         ocfs2_build_lock_name(OCFS2_LOCK_TYPE_REFCOUNT, ref_blkno,
744                               generation, lockres->l_name);
745         ocfs2_lock_res_init_common(osb, lockres, OCFS2_LOCK_TYPE_REFCOUNT,
746                                    &ocfs2_refcount_block_lops, osb);
747 }
748 
749 void ocfs2_lock_res_free(struct ocfs2_lock_res *res)
750 {
751         if (!(res->l_flags & OCFS2_LOCK_INITIALIZED))
752                 return;
753 
754         ocfs2_remove_lockres_tracking(res);
755 
756         mlog_bug_on_msg(!list_empty(&res->l_blocked_list),
757                         "Lockres %s is on the blocked list\n",
758                         res->l_name);
759         mlog_bug_on_msg(!list_empty(&res->l_mask_waiters),
760                         "Lockres %s has mask waiters pending\n",
761                         res->l_name);
762         mlog_bug_on_msg(spin_is_locked(&res->l_lock),
763                         "Lockres %s is locked\n",
764                         res->l_name);
765         mlog_bug_on_msg(res->l_ro_holders,
766                         "Lockres %s has %u ro holders\n",
767                         res->l_name, res->l_ro_holders);
768         mlog_bug_on_msg(res->l_ex_holders,
769                         "Lockres %s has %u ex holders\n",
770                         res->l_name, res->l_ex_holders);
771 
772         /* Need to clear out the lock status block for the dlm */
773         memset(&res->l_lksb, 0, sizeof(res->l_lksb));
774 
775         res->l_flags = 0UL;
776 }
777 
778 /*
779  * Keep a list of processes who have interest in a lockres.
780  * Note: this is now only uesed for check recursive cluster locking.
781  */
782 static inline void ocfs2_add_holder(struct ocfs2_lock_res *lockres,
783                                    struct ocfs2_lock_holder *oh)
784 {
785         INIT_LIST_HEAD(&oh->oh_list);
786         oh->oh_owner_pid = get_pid(task_pid(current));
787 
788         spin_lock(&lockres->l_lock);
789         list_add_tail(&oh->oh_list, &lockres->l_holders);
790         spin_unlock(&lockres->l_lock);
791 }
792 
793 static struct ocfs2_lock_holder *
794 ocfs2_pid_holder(struct ocfs2_lock_res *lockres,
795                 struct pid *pid)
796 {
797         struct ocfs2_lock_holder *oh;
798 
799         spin_lock(&lockres->l_lock);
800         list_for_each_entry(oh, &lockres->l_holders, oh_list) {
801                 if (oh->oh_owner_pid == pid) {
802                         spin_unlock(&lockres->l_lock);
803                         return oh;
804                 }
805         }
806         spin_unlock(&lockres->l_lock);
807         return NULL;
808 }
809 
810 static inline void ocfs2_remove_holder(struct ocfs2_lock_res *lockres,
811                                        struct ocfs2_lock_holder *oh)
812 {
813         spin_lock(&lockres->l_lock);
814         list_del(&oh->oh_list);
815         spin_unlock(&lockres->l_lock);
816 
817         put_pid(oh->oh_owner_pid);
818 }
819 
820 
821 static inline void ocfs2_inc_holders(struct ocfs2_lock_res *lockres,
822                                      int level)
823 {
824         BUG_ON(!lockres);
825 
826         switch(level) {
827         case DLM_LOCK_EX:
828                 lockres->l_ex_holders++;
829                 break;
830         case DLM_LOCK_PR:
831                 lockres->l_ro_holders++;
832                 break;
833         default:
834                 BUG();
835         }
836 }
837 
838 static inline void ocfs2_dec_holders(struct ocfs2_lock_res *lockres,
839                                      int level)
840 {
841         BUG_ON(!lockres);
842 
843         switch(level) {
844         case DLM_LOCK_EX:
845                 BUG_ON(!lockres->l_ex_holders);
846                 lockres->l_ex_holders--;
847                 break;
848         case DLM_LOCK_PR:
849                 BUG_ON(!lockres->l_ro_holders);
850                 lockres->l_ro_holders--;
851                 break;
852         default:
853                 BUG();
854         }
855 }
856 
857 /* WARNING: This function lives in a world where the only three lock
858  * levels are EX, PR, and NL. It *will* have to be adjusted when more
859  * lock types are added. */
860 static inline int ocfs2_highest_compat_lock_level(int level)
861 {
862         int new_level = DLM_LOCK_EX;
863 
864         if (level == DLM_LOCK_EX)
865                 new_level = DLM_LOCK_NL;
866         else if (level == DLM_LOCK_PR)
867                 new_level = DLM_LOCK_PR;
868         return new_level;
869 }
870 
871 static void lockres_set_flags(struct ocfs2_lock_res *lockres,
872                               unsigned long newflags)
873 {
874         struct ocfs2_mask_waiter *mw, *tmp;
875 
876         assert_spin_locked(&lockres->l_lock);
877 
878         lockres->l_flags = newflags;
879 
880         list_for_each_entry_safe(mw, tmp, &lockres->l_mask_waiters, mw_item) {
881                 if ((lockres->l_flags & mw->mw_mask) != mw->mw_goal)
882                         continue;
883 
884                 list_del_init(&mw->mw_item);
885                 mw->mw_status = 0;
886                 complete(&mw->mw_complete);
887         }
888 }
889 static void lockres_or_flags(struct ocfs2_lock_res *lockres, unsigned long or)
890 {
891         lockres_set_flags(lockres, lockres->l_flags | or);
892 }
893 static void lockres_clear_flags(struct ocfs2_lock_res *lockres,
894                                 unsigned long clear)
895 {
896         lockres_set_flags(lockres, lockres->l_flags & ~clear);
897 }
898 
899 static inline void ocfs2_generic_handle_downconvert_action(struct ocfs2_lock_res *lockres)
900 {
901         BUG_ON(!(lockres->l_flags & OCFS2_LOCK_BUSY));
902         BUG_ON(!(lockres->l_flags & OCFS2_LOCK_ATTACHED));
903         BUG_ON(!(lockres->l_flags & OCFS2_LOCK_BLOCKED));
904         BUG_ON(lockres->l_blocking <= DLM_LOCK_NL);
905 
906         lockres->l_level = lockres->l_requested;
907         if (lockres->l_level <=
908             ocfs2_highest_compat_lock_level(lockres->l_blocking)) {
909                 lockres->l_blocking = DLM_LOCK_NL;
910                 lockres_clear_flags(lockres, OCFS2_LOCK_BLOCKED);
911         }
912         lockres_clear_flags(lockres, OCFS2_LOCK_BUSY);
913 }
914 
915 static inline void ocfs2_generic_handle_convert_action(struct ocfs2_lock_res *lockres)
916 {
917         BUG_ON(!(lockres->l_flags & OCFS2_LOCK_BUSY));
918         BUG_ON(!(lockres->l_flags & OCFS2_LOCK_ATTACHED));
919 
920         /* Convert from RO to EX doesn't really need anything as our
921          * information is already up to data. Convert from NL to
922          * *anything* however should mark ourselves as needing an
923          * update */
924         if (lockres->l_level == DLM_LOCK_NL &&
925             lockres->l_ops->flags & LOCK_TYPE_REQUIRES_REFRESH)
926                 lockres_or_flags(lockres, OCFS2_LOCK_NEEDS_REFRESH);
927 
928         lockres->l_level = lockres->l_requested;
929 
930         /*
931          * We set the OCFS2_LOCK_UPCONVERT_FINISHING flag before clearing
932          * the OCFS2_LOCK_BUSY flag to prevent the dc thread from
933          * downconverting the lock before the upconvert has fully completed.
934          * Do not prevent the dc thread from downconverting if NONBLOCK lock
935          * had already returned.
936          */
937         if (!(lockres->l_flags & OCFS2_LOCK_NONBLOCK_FINISHED))
938                 lockres_or_flags(lockres, OCFS2_LOCK_UPCONVERT_FINISHING);
939         else
940                 lockres_clear_flags(lockres, OCFS2_LOCK_NONBLOCK_FINISHED);
941 
942         lockres_clear_flags(lockres, OCFS2_LOCK_BUSY);
943 }
944 
945 static inline void ocfs2_generic_handle_attach_action(struct ocfs2_lock_res *lockres)
946 {
947         BUG_ON((!(lockres->l_flags & OCFS2_LOCK_BUSY)));
948         BUG_ON(lockres->l_flags & OCFS2_LOCK_ATTACHED);
949 
950         if (lockres->l_requested > DLM_LOCK_NL &&
951             !(lockres->l_flags & OCFS2_LOCK_LOCAL) &&
952             lockres->l_ops->flags & LOCK_TYPE_REQUIRES_REFRESH)
953                 lockres_or_flags(lockres, OCFS2_LOCK_NEEDS_REFRESH);
954 
955         lockres->l_level = lockres->l_requested;
956         lockres_or_flags(lockres, OCFS2_LOCK_ATTACHED);
957         lockres_clear_flags(lockres, OCFS2_LOCK_BUSY);
958 }
959 
960 static int ocfs2_generic_handle_bast(struct ocfs2_lock_res *lockres,
961                                      int level)
962 {
963         int needs_downconvert = 0;
964 
965         assert_spin_locked(&lockres->l_lock);
966 
967         if (level > lockres->l_blocking) {
968                 /* only schedule a downconvert if we haven't already scheduled
969                  * one that goes low enough to satisfy the level we're
970                  * blocking.  this also catches the case where we get
971                  * duplicate BASTs */
972                 if (ocfs2_highest_compat_lock_level(level) <
973                     ocfs2_highest_compat_lock_level(lockres->l_blocking))
974                         needs_downconvert = 1;
975 
976                 lockres->l_blocking = level;
977         }
978 
979         mlog(ML_BASTS, "lockres %s, block %d, level %d, l_block %d, dwn %d\n",
980              lockres->l_name, level, lockres->l_level, lockres->l_blocking,
981              needs_downconvert);
982 
983         if (needs_downconvert)
984                 lockres_or_flags(lockres, OCFS2_LOCK_BLOCKED);
985         mlog(0, "needs_downconvert = %d\n", needs_downconvert);
986         return needs_downconvert;
987 }
988 
989 /*
990  * OCFS2_LOCK_PENDING and l_pending_gen.
991  *
992  * Why does OCFS2_LOCK_PENDING exist?  To close a race between setting
993  * OCFS2_LOCK_BUSY and calling ocfs2_dlm_lock().  See ocfs2_unblock_lock()
994  * for more details on the race.
995  *
996  * OCFS2_LOCK_PENDING closes the race quite nicely.  However, it introduces
997  * a race on itself.  In o2dlm, we can get the ast before ocfs2_dlm_lock()
998  * returns.  The ast clears OCFS2_LOCK_BUSY, and must therefore clear
999  * OCFS2_LOCK_PENDING at the same time.  When ocfs2_dlm_lock() returns,
1000  * the caller is going to try to clear PENDING again.  If nothing else is
1001  * happening, __lockres_clear_pending() sees PENDING is unset and does
1002  * nothing.
1003  *
1004  * But what if another path (eg downconvert thread) has just started a
1005  * new locking action?  The other path has re-set PENDING.  Our path
1006  * cannot clear PENDING, because that will re-open the original race
1007  * window.
1008  *
1009  * [Example]
1010  *
1011  * ocfs2_meta_lock()
1012  *  ocfs2_cluster_lock()
1013  *   set BUSY
1014  *   set PENDING
1015  *   drop l_lock
1016  *   ocfs2_dlm_lock()
1017  *    ocfs2_locking_ast()               ocfs2_downconvert_thread()
1018  *     clear PENDING                     ocfs2_unblock_lock()
1019  *                                        take_l_lock
1020  *                                        !BUSY
1021  *                                        ocfs2_prepare_downconvert()
1022  *                                         set BUSY
1023  *                                         set PENDING
1024  *                                        drop l_lock
1025  *   take l_lock
1026  *   clear PENDING
1027  *   drop l_lock
1028  *                      <window>
1029  *                                        ocfs2_dlm_lock()
1030  *
1031  * So as you can see, we now have a window where l_lock is not held,
1032  * PENDING is not set, and ocfs2_dlm_lock() has not been called.
1033  *
1034  * The core problem is that ocfs2_cluster_lock() has cleared the PENDING
1035  * set by ocfs2_prepare_downconvert().  That wasn't nice.
1036  *
1037  * To solve this we introduce l_pending_gen.  A call to
1038  * lockres_clear_pending() will only do so when it is passed a generation
1039  * number that matches the lockres.  lockres_set_pending() will return the
1040  * current generation number.  When ocfs2_cluster_lock() goes to clear
1041  * PENDING, it passes the generation it got from set_pending().  In our
1042  * example above, the generation numbers will *not* match.  Thus,
1043  * ocfs2_cluster_lock() will not clear the PENDING set by
1044  * ocfs2_prepare_downconvert().
1045  */
1046 
1047 /* Unlocked version for ocfs2_locking_ast() */
1048 static void __lockres_clear_pending(struct ocfs2_lock_res *lockres,
1049                                     unsigned int generation,
1050                                     struct ocfs2_super *osb)
1051 {
1052         assert_spin_locked(&lockres->l_lock);
1053 
1054         /*
1055          * The ast and locking functions can race us here.  The winner
1056          * will clear pending, the loser will not.
1057          */
1058         if (!(lockres->l_flags & OCFS2_LOCK_PENDING) ||
1059             (lockres->l_pending_gen != generation))
1060                 return;
1061 
1062         lockres_clear_flags(lockres, OCFS2_LOCK_PENDING);
1063         lockres->l_pending_gen++;
1064 
1065         /*
1066          * The downconvert thread may have skipped us because we
1067          * were PENDING.  Wake it up.
1068          */
1069         if (lockres->l_flags & OCFS2_LOCK_BLOCKED)
1070                 ocfs2_wake_downconvert_thread(osb);
1071 }
1072 
1073 /* Locked version for callers of ocfs2_dlm_lock() */
1074 static void lockres_clear_pending(struct ocfs2_lock_res *lockres,
1075                                   unsigned int generation,
1076                                   struct ocfs2_super *osb)
1077 {
1078         unsigned long flags;
1079 
1080         spin_lock_irqsave(&lockres->l_lock, flags);
1081         __lockres_clear_pending(lockres, generation, osb);
1082         spin_unlock_irqrestore(&lockres->l_lock, flags);
1083 }
1084 
1085 static unsigned int lockres_set_pending(struct ocfs2_lock_res *lockres)
1086 {
1087         assert_spin_locked(&lockres->l_lock);
1088         BUG_ON(!(lockres->l_flags & OCFS2_LOCK_BUSY));
1089 
1090         lockres_or_flags(lockres, OCFS2_LOCK_PENDING);
1091 
1092         return lockres->l_pending_gen;
1093 }
1094 
1095 static void ocfs2_blocking_ast(struct ocfs2_dlm_lksb *lksb, int level)
1096 {
1097         struct ocfs2_lock_res *lockres = ocfs2_lksb_to_lock_res(lksb);
1098         struct ocfs2_super *osb = ocfs2_get_lockres_osb(lockres);
1099         int needs_downconvert;
1100         unsigned long flags;
1101 
1102         BUG_ON(level <= DLM_LOCK_NL);
1103 
1104         mlog(ML_BASTS, "BAST fired for lockres %s, blocking %d, level %d, "
1105              "type %s\n", lockres->l_name, level, lockres->l_level,
1106              ocfs2_lock_type_string(lockres->l_type));
1107 
1108         /*
1109          * We can skip the bast for locks which don't enable caching -
1110          * they'll be dropped at the earliest possible time anyway.
1111          */
1112         if (lockres->l_flags & OCFS2_LOCK_NOCACHE)
1113                 return;
1114 
1115         spin_lock_irqsave(&lockres->l_lock, flags);
1116         needs_downconvert = ocfs2_generic_handle_bast(lockres, level);
1117         if (needs_downconvert)
1118                 ocfs2_schedule_blocked_lock(osb, lockres);
1119         spin_unlock_irqrestore(&lockres->l_lock, flags);
1120 
1121         wake_up(&lockres->l_event);
1122 
1123         ocfs2_wake_downconvert_thread(osb);
1124 }
1125 
1126 static void ocfs2_locking_ast(struct ocfs2_dlm_lksb *lksb)
1127 {
1128         struct ocfs2_lock_res *lockres = ocfs2_lksb_to_lock_res(lksb);
1129         struct ocfs2_super *osb = ocfs2_get_lockres_osb(lockres);
1130         unsigned long flags;
1131         int status;
1132 
1133         spin_lock_irqsave(&lockres->l_lock, flags);
1134 
1135         status = ocfs2_dlm_lock_status(&lockres->l_lksb);
1136 
1137         if (status == -EAGAIN) {
1138                 lockres_clear_flags(lockres, OCFS2_LOCK_BUSY);
1139                 goto out;
1140         }
1141 
1142         if (status) {
1143                 mlog(ML_ERROR, "lockres %s: lksb status value of %d!\n",
1144                      lockres->l_name, status);
1145                 spin_unlock_irqrestore(&lockres->l_lock, flags);
1146                 return;
1147         }
1148 
1149         mlog(ML_BASTS, "AST fired for lockres %s, action %d, unlock %d, "
1150              "level %d => %d\n", lockres->l_name, lockres->l_action,
1151              lockres->l_unlock_action, lockres->l_level, lockres->l_requested);
1152 
1153         switch(lockres->l_action) {
1154         case OCFS2_AST_ATTACH:
1155                 ocfs2_generic_handle_attach_action(lockres);
1156                 lockres_clear_flags(lockres, OCFS2_LOCK_LOCAL);
1157                 break;
1158         case OCFS2_AST_CONVERT:
1159                 ocfs2_generic_handle_convert_action(lockres);
1160                 break;
1161         case OCFS2_AST_DOWNCONVERT:
1162                 ocfs2_generic_handle_downconvert_action(lockres);
1163                 break;
1164         default:
1165                 mlog(ML_ERROR, "lockres %s: AST fired with invalid action: %u, "
1166                      "flags 0x%lx, unlock: %u\n",
1167                      lockres->l_name, lockres->l_action, lockres->l_flags,
1168                      lockres->l_unlock_action);
1169                 BUG();
1170         }
1171 out:
1172         /* set it to something invalid so if we get called again we
1173          * can catch it. */
1174         lockres->l_action = OCFS2_AST_INVALID;
1175 
1176         /* Did we try to cancel this lock?  Clear that state */
1177         if (lockres->l_unlock_action == OCFS2_UNLOCK_CANCEL_CONVERT)
1178                 lockres->l_unlock_action = OCFS2_UNLOCK_INVALID;
1179 
1180         /*
1181          * We may have beaten the locking functions here.  We certainly
1182          * know that dlm_lock() has been called :-)
1183          * Because we can't have two lock calls in flight at once, we
1184          * can use lockres->l_pending_gen.
1185          */
1186         __lockres_clear_pending(lockres, lockres->l_pending_gen,  osb);
1187 
1188         wake_up(&lockres->l_event);
1189         spin_unlock_irqrestore(&lockres->l_lock, flags);
1190 }
1191 
1192 static void ocfs2_unlock_ast(struct ocfs2_dlm_lksb *lksb, int error)
1193 {
1194         struct ocfs2_lock_res *lockres = ocfs2_lksb_to_lock_res(lksb);
1195         unsigned long flags;
1196 
1197         mlog(ML_BASTS, "UNLOCK AST fired for lockres %s, action = %d\n",
1198              lockres->l_name, lockres->l_unlock_action);
1199 
1200         spin_lock_irqsave(&lockres->l_lock, flags);
1201         if (error) {
1202                 mlog(ML_ERROR, "Dlm passes error %d for lock %s, "
1203                      "unlock_action %d\n", error, lockres->l_name,
1204                      lockres->l_unlock_action);
1205                 spin_unlock_irqrestore(&lockres->l_lock, flags);
1206                 return;
1207         }
1208 
1209         switch(lockres->l_unlock_action) {
1210         case OCFS2_UNLOCK_CANCEL_CONVERT:
1211                 mlog(0, "Cancel convert success for %s\n", lockres->l_name);
1212                 lockres->l_action = OCFS2_AST_INVALID;
1213                 /* Downconvert thread may have requeued this lock, we
1214                  * need to wake it. */
1215                 if (lockres->l_flags & OCFS2_LOCK_BLOCKED)
1216                         ocfs2_wake_downconvert_thread(ocfs2_get_lockres_osb(lockres));
1217                 break;
1218         case OCFS2_UNLOCK_DROP_LOCK:
1219                 lockres->l_level = DLM_LOCK_IV;
1220                 break;
1221         default:
1222                 BUG();
1223         }
1224 
1225         lockres_clear_flags(lockres, OCFS2_LOCK_BUSY);
1226         lockres->l_unlock_action = OCFS2_UNLOCK_INVALID;
1227         wake_up(&lockres->l_event);
1228         spin_unlock_irqrestore(&lockres->l_lock, flags);
1229 }
1230 
1231 /*
1232  * This is the filesystem locking protocol.  It provides the lock handling
1233  * hooks for the underlying DLM.  It has a maximum version number.
1234  * The version number allows interoperability with systems running at
1235  * the same major number and an equal or smaller minor number.
1236  *
1237  * Whenever the filesystem does new things with locks (adds or removes a
1238  * lock, orders them differently, does different things underneath a lock),
1239  * the version must be changed.  The protocol is negotiated when joining
1240  * the dlm domain.  A node may join the domain if its major version is
1241  * identical to all other nodes and its minor version is greater than
1242  * or equal to all other nodes.  When its minor version is greater than
1243  * the other nodes, it will run at the minor version specified by the
1244  * other nodes.
1245  *
1246  * If a locking change is made that will not be compatible with older
1247  * versions, the major number must be increased and the minor version set
1248  * to zero.  If a change merely adds a behavior that can be disabled when
1249  * speaking to older versions, the minor version must be increased.  If a
1250  * change adds a fully backwards compatible change (eg, LVB changes that
1251  * are just ignored by older versions), the version does not need to be
1252  * updated.
1253  */
1254 static struct ocfs2_locking_protocol lproto = {
1255         .lp_max_version = {
1256                 .pv_major = OCFS2_LOCKING_PROTOCOL_MAJOR,
1257                 .pv_minor = OCFS2_LOCKING_PROTOCOL_MINOR,
1258         },
1259         .lp_lock_ast            = ocfs2_locking_ast,
1260         .lp_blocking_ast        = ocfs2_blocking_ast,
1261         .lp_unlock_ast          = ocfs2_unlock_ast,
1262 };
1263 
1264 void ocfs2_set_locking_protocol(void)
1265 {
1266         ocfs2_stack_glue_set_max_proto_version(&lproto.lp_max_version);
1267 }
1268 
1269 static inline void ocfs2_recover_from_dlm_error(struct ocfs2_lock_res *lockres,
1270                                                 int convert)
1271 {
1272         unsigned long flags;
1273 
1274         spin_lock_irqsave(&lockres->l_lock, flags);
1275         lockres_clear_flags(lockres, OCFS2_LOCK_BUSY);
1276         lockres_clear_flags(lockres, OCFS2_LOCK_UPCONVERT_FINISHING);
1277         if (convert)
1278                 lockres->l_action = OCFS2_AST_INVALID;
1279         else
1280                 lockres->l_unlock_action = OCFS2_UNLOCK_INVALID;
1281         spin_unlock_irqrestore(&lockres->l_lock, flags);
1282 
1283         wake_up(&lockres->l_event);
1284 }
1285 
1286 /* Note: If we detect another process working on the lock (i.e.,
1287  * OCFS2_LOCK_BUSY), we'll bail out returning 0. It's up to the caller
1288  * to do the right thing in that case.
1289  */
1290 static int ocfs2_lock_create(struct ocfs2_super *osb,
1291                              struct ocfs2_lock_res *lockres,
1292                              int level,
1293                              u32 dlm_flags)
1294 {
1295         int ret = 0;
1296         unsigned long flags;
1297         unsigned int gen;
1298 
1299         mlog(0, "lock %s, level = %d, flags = %u\n", lockres->l_name, level,
1300              dlm_flags);
1301 
1302         spin_lock_irqsave(&lockres->l_lock, flags);
1303         if ((lockres->l_flags & OCFS2_LOCK_ATTACHED) ||
1304             (lockres->l_flags & OCFS2_LOCK_BUSY)) {
1305                 spin_unlock_irqrestore(&lockres->l_lock, flags);
1306                 goto bail;
1307         }
1308 
1309         lockres->l_action = OCFS2_AST_ATTACH;
1310         lockres->l_requested = level;
1311         lockres_or_flags(lockres, OCFS2_LOCK_BUSY);
1312         gen = lockres_set_pending(lockres);
1313         spin_unlock_irqrestore(&lockres->l_lock, flags);
1314 
1315         ret = ocfs2_dlm_lock(osb->cconn,
1316                              level,
1317                              &lockres->l_lksb,
1318                              dlm_flags,
1319                              lockres->l_name,
1320                              OCFS2_LOCK_ID_MAX_LEN - 1);
1321         lockres_clear_pending(lockres, gen, osb);
1322         if (ret) {
1323                 ocfs2_log_dlm_error("ocfs2_dlm_lock", ret, lockres);
1324                 ocfs2_recover_from_dlm_error(lockres, 1);
1325         }
1326 
1327         mlog(0, "lock %s, return from ocfs2_dlm_lock\n", lockres->l_name);
1328 
1329 bail:
1330         return ret;
1331 }
1332 
1333 static inline int ocfs2_check_wait_flag(struct ocfs2_lock_res *lockres,
1334                                         int flag)
1335 {
1336         unsigned long flags;
1337         int ret;
1338 
1339         spin_lock_irqsave(&lockres->l_lock, flags);
1340         ret = lockres->l_flags & flag;
1341         spin_unlock_irqrestore(&lockres->l_lock, flags);
1342 
1343         return ret;
1344 }
1345 
1346 static inline void ocfs2_wait_on_busy_lock(struct ocfs2_lock_res *lockres)
1347 
1348 {
1349         wait_event(lockres->l_event,
1350                    !ocfs2_check_wait_flag(lockres, OCFS2_LOCK_BUSY));
1351 }
1352 
1353 static inline void ocfs2_wait_on_refreshing_lock(struct ocfs2_lock_res *lockres)
1354 
1355 {
1356         wait_event(lockres->l_event,
1357                    !ocfs2_check_wait_flag(lockres, OCFS2_LOCK_REFRESHING));
1358 }
1359 
1360 /* predict what lock level we'll be dropping down to on behalf
1361  * of another node, and return true if the currently wanted
1362  * level will be compatible with it. */
1363 static inline int ocfs2_may_continue_on_blocked_lock(struct ocfs2_lock_res *lockres,
1364                                                      int wanted)
1365 {
1366         BUG_ON(!(lockres->l_flags & OCFS2_LOCK_BLOCKED));
1367 
1368         return wanted <= ocfs2_highest_compat_lock_level(lockres->l_blocking);
1369 }
1370 
1371 static void ocfs2_init_mask_waiter(struct ocfs2_mask_waiter *mw)
1372 {
1373         INIT_LIST_HEAD(&mw->mw_item);
1374         init_completion(&mw->mw_complete);
1375         ocfs2_init_start_time(mw);
1376 }
1377 
1378 static int ocfs2_wait_for_mask(struct ocfs2_mask_waiter *mw)
1379 {
1380         wait_for_completion(&mw->mw_complete);
1381         /* Re-arm the completion in case we want to wait on it again */
1382         reinit_completion(&mw->mw_complete);
1383         return mw->mw_status;
1384 }
1385 
1386 static void lockres_add_mask_waiter(struct ocfs2_lock_res *lockres,
1387                                     struct ocfs2_mask_waiter *mw,
1388                                     unsigned long mask,
1389                                     unsigned long goal)
1390 {
1391         BUG_ON(!list_empty(&mw->mw_item));
1392 
1393         assert_spin_locked(&lockres->l_lock);
1394 
1395         list_add_tail(&mw->mw_item, &lockres->l_mask_waiters);
1396         mw->mw_mask = mask;
1397         mw->mw_goal = goal;
1398 }
1399 
1400 /* returns 0 if the mw that was removed was already satisfied, -EBUSY
1401  * if the mask still hadn't reached its goal */
1402 static int __lockres_remove_mask_waiter(struct ocfs2_lock_res *lockres,
1403                                       struct ocfs2_mask_waiter *mw)
1404 {
1405         int ret = 0;
1406 
1407         assert_spin_locked(&lockres->l_lock);
1408         if (!list_empty(&mw->mw_item)) {
1409                 if ((lockres->l_flags & mw->mw_mask) != mw->mw_goal)
1410                         ret = -EBUSY;
1411 
1412                 list_del_init(&mw->mw_item);
1413                 init_completion(&mw->mw_complete);
1414         }
1415 
1416         return ret;
1417 }
1418 
1419 static int lockres_remove_mask_waiter(struct ocfs2_lock_res *lockres,
1420                                       struct ocfs2_mask_waiter *mw)
1421 {
1422         unsigned long flags;
1423         int ret = 0;
1424 
1425         spin_lock_irqsave(&lockres->l_lock, flags);
1426         ret = __lockres_remove_mask_waiter(lockres, mw);
1427         spin_unlock_irqrestore(&lockres->l_lock, flags);
1428 
1429         return ret;
1430 
1431 }
1432 
1433 static int ocfs2_wait_for_mask_interruptible(struct ocfs2_mask_waiter *mw,
1434                                              struct ocfs2_lock_res *lockres)
1435 {
1436         int ret;
1437 
1438         ret = wait_for_completion_interruptible(&mw->mw_complete);
1439         if (ret)
1440                 lockres_remove_mask_waiter(lockres, mw);
1441         else
1442                 ret = mw->mw_status;
1443         /* Re-arm the completion in case we want to wait on it again */
1444         reinit_completion(&mw->mw_complete);
1445         return ret;
1446 }
1447 
1448 static int __ocfs2_cluster_lock(struct ocfs2_super *osb,
1449                                 struct ocfs2_lock_res *lockres,
1450                                 int level,
1451                                 u32 lkm_flags,
1452                                 int arg_flags,
1453                                 int l_subclass,
1454                                 unsigned long caller_ip)
1455 {
1456         struct ocfs2_mask_waiter mw;
1457         int wait, catch_signals = !(osb->s_mount_opt & OCFS2_MOUNT_NOINTR);
1458         int ret = 0; /* gcc doesn't realize wait = 1 guarantees ret is set */
1459         unsigned long flags;
1460         unsigned int gen;
1461         int noqueue_attempted = 0;
1462         int dlm_locked = 0;
1463         int kick_dc = 0;
1464 
1465         if (!(lockres->l_flags & OCFS2_LOCK_INITIALIZED)) {
1466                 mlog_errno(-EINVAL);
1467                 return -EINVAL;
1468         }
1469 
1470         ocfs2_init_mask_waiter(&mw);
1471 
1472         if (lockres->l_ops->flags & LOCK_TYPE_USES_LVB)
1473                 lkm_flags |= DLM_LKF_VALBLK;
1474 
1475 again:
1476         wait = 0;
1477 
1478         spin_lock_irqsave(&lockres->l_lock, flags);
1479 
1480         if (catch_signals && signal_pending(current)) {
1481                 ret = -ERESTARTSYS;
1482                 goto unlock;
1483         }
1484 
1485         mlog_bug_on_msg(lockres->l_flags & OCFS2_LOCK_FREEING,
1486                         "Cluster lock called on freeing lockres %s! flags "
1487                         "0x%lx\n", lockres->l_name, lockres->l_flags);
1488 
1489         /* We only compare against the currently granted level
1490          * here. If the lock is blocked waiting on a downconvert,
1491          * we'll get caught below. */
1492         if (lockres->l_flags & OCFS2_LOCK_BUSY &&
1493             level > lockres->l_level) {
1494                 /* is someone sitting in dlm_lock? If so, wait on
1495                  * them. */
1496                 lockres_add_mask_waiter(lockres, &mw, OCFS2_LOCK_BUSY, 0);
1497                 wait = 1;
1498                 goto unlock;
1499         }
1500 
1501         if (lockres->l_flags & OCFS2_LOCK_UPCONVERT_FINISHING) {
1502                 /*
1503                  * We've upconverted. If the lock now has a level we can
1504                  * work with, we take it. If, however, the lock is not at the
1505                  * required level, we go thru the full cycle. One way this could
1506                  * happen is if a process requesting an upconvert to PR is
1507                  * closely followed by another requesting upconvert to an EX.
1508                  * If the process requesting EX lands here, we want it to
1509                  * continue attempting to upconvert and let the process
1510                  * requesting PR take the lock.
1511                  * If multiple processes request upconvert to PR, the first one
1512                  * here will take the lock. The others will have to go thru the
1513                  * OCFS2_LOCK_BLOCKED check to ensure that there is no pending
1514                  * downconvert request.
1515                  */
1516                 if (level <= lockres->l_level)
1517                         goto update_holders;
1518         }
1519 
1520         if (lockres->l_flags & OCFS2_LOCK_BLOCKED &&
1521             !ocfs2_may_continue_on_blocked_lock(lockres, level)) {
1522                 /* is the lock is currently blocked on behalf of
1523                  * another node */
1524                 lockres_add_mask_waiter(lockres, &mw, OCFS2_LOCK_BLOCKED, 0);
1525                 wait = 1;
1526                 goto unlock;
1527         }
1528 
1529         if (level > lockres->l_level) {
1530                 if (noqueue_attempted > 0) {
1531                         ret = -EAGAIN;
1532                         goto unlock;
1533                 }
1534                 if (lkm_flags & DLM_LKF_NOQUEUE)
1535                         noqueue_attempted = 1;
1536 
1537                 if (lockres->l_action != OCFS2_AST_INVALID)
1538                         mlog(ML_ERROR, "lockres %s has action %u pending\n",
1539                              lockres->l_name, lockres->l_action);
1540 
1541                 if (!(lockres->l_flags & OCFS2_LOCK_ATTACHED)) {
1542                         lockres->l_action = OCFS2_AST_ATTACH;
1543                         lkm_flags &= ~DLM_LKF_CONVERT;
1544                 } else {
1545                         lockres->l_action = OCFS2_AST_CONVERT;
1546                         lkm_flags |= DLM_LKF_CONVERT;
1547                 }
1548 
1549                 lockres->l_requested = level;
1550                 lockres_or_flags(lockres, OCFS2_LOCK_BUSY);
1551                 gen = lockres_set_pending(lockres);
1552                 spin_unlock_irqrestore(&lockres->l_lock, flags);
1553 
1554                 BUG_ON(level == DLM_LOCK_IV);
1555                 BUG_ON(level == DLM_LOCK_NL);
1556 
1557                 mlog(ML_BASTS, "lockres %s, convert from %d to %d\n",
1558                      lockres->l_name, lockres->l_level, level);
1559 
1560                 /* call dlm_lock to upgrade lock now */
1561                 ret = ocfs2_dlm_lock(osb->cconn,
1562                                      level,
1563                                      &lockres->l_lksb,
1564                                      lkm_flags,
1565                                      lockres->l_name,
1566                                      OCFS2_LOCK_ID_MAX_LEN - 1);
1567                 lockres_clear_pending(lockres, gen, osb);
1568                 if (ret) {
1569                         if (!(lkm_flags & DLM_LKF_NOQUEUE) ||
1570                             (ret != -EAGAIN)) {
1571                                 ocfs2_log_dlm_error("ocfs2_dlm_lock",
1572                                                     ret, lockres);
1573                         }
1574                         ocfs2_recover_from_dlm_error(lockres, 1);
1575                         goto out;
1576                 }
1577                 dlm_locked = 1;
1578 
1579                 mlog(0, "lock %s, successful return from ocfs2_dlm_lock\n",
1580                      lockres->l_name);
1581 
1582                 /* At this point we've gone inside the dlm and need to
1583                  * complete our work regardless. */
1584                 catch_signals = 0;
1585 
1586                 /* wait for busy to clear and carry on */
1587                 goto again;
1588         }
1589 
1590 update_holders:
1591         /* Ok, if we get here then we're good to go. */
1592         ocfs2_inc_holders(lockres, level);
1593 
1594         ret = 0;
1595 unlock:
1596         lockres_clear_flags(lockres, OCFS2_LOCK_UPCONVERT_FINISHING);
1597 
1598         /* ocfs2_unblock_lock reques on seeing OCFS2_LOCK_UPCONVERT_FINISHING */
1599         kick_dc = (lockres->l_flags & OCFS2_LOCK_BLOCKED);
1600 
1601         spin_unlock_irqrestore(&lockres->l_lock, flags);
1602         if (kick_dc)
1603                 ocfs2_wake_downconvert_thread(osb);
1604 out:
1605         /*
1606          * This is helping work around a lock inversion between the page lock
1607          * and dlm locks.  One path holds the page lock while calling aops
1608          * which block acquiring dlm locks.  The voting thread holds dlm
1609          * locks while acquiring page locks while down converting data locks.
1610          * This block is helping an aop path notice the inversion and back
1611          * off to unlock its page lock before trying the dlm lock again.
1612          */
1613         if (wait && arg_flags & OCFS2_LOCK_NONBLOCK &&
1614             mw.mw_mask & (OCFS2_LOCK_BUSY|OCFS2_LOCK_BLOCKED)) {
1615                 wait = 0;
1616                 spin_lock_irqsave(&lockres->l_lock, flags);
1617                 if (__lockres_remove_mask_waiter(lockres, &mw)) {
1618                         if (dlm_locked)
1619                                 lockres_or_flags(lockres,
1620                                         OCFS2_LOCK_NONBLOCK_FINISHED);
1621                         spin_unlock_irqrestore(&lockres->l_lock, flags);
1622                         ret = -EAGAIN;
1623                 } else {
1624                         spin_unlock_irqrestore(&lockres->l_lock, flags);
1625                         goto again;
1626                 }
1627         }
1628         if (wait) {
1629                 ret = ocfs2_wait_for_mask(&mw);
1630                 if (ret == 0)
1631                         goto again;
1632                 mlog_errno(ret);
1633         }
1634         ocfs2_update_lock_stats(lockres, level, &mw, ret);
1635 
1636 #ifdef CONFIG_DEBUG_LOCK_ALLOC
1637         if (!ret && lockres->l_lockdep_map.key != NULL) {
1638                 if (level == DLM_LOCK_PR)
1639                         rwsem_acquire_read(&lockres->l_lockdep_map, l_subclass,
1640                                 !!(arg_flags & OCFS2_META_LOCK_NOQUEUE),
1641                                 caller_ip);
1642                 else
1643                         rwsem_acquire(&lockres->l_lockdep_map, l_subclass,
1644                                 !!(arg_flags & OCFS2_META_LOCK_NOQUEUE),
1645                                 caller_ip);
1646         }
1647 #endif
1648         return ret;
1649 }
1650 
1651 static inline int ocfs2_cluster_lock(struct ocfs2_super *osb,
1652                                      struct ocfs2_lock_res *lockres,
1653                                      int level,
1654                                      u32 lkm_flags,
1655                                      int arg_flags)
1656 {
1657         return __ocfs2_cluster_lock(osb, lockres, level, lkm_flags, arg_flags,
1658                                     0, _RET_IP_);
1659 }
1660 
1661 
1662 static void __ocfs2_cluster_unlock(struct ocfs2_super *osb,
1663                                    struct ocfs2_lock_res *lockres,
1664                                    int level,
1665                                    unsigned long caller_ip)
1666 {
1667         unsigned long flags;
1668 
1669         spin_lock_irqsave(&lockres->l_lock, flags);
1670         ocfs2_dec_holders(lockres, level);
1671         ocfs2_downconvert_on_unlock(osb, lockres);
1672         spin_unlock_irqrestore(&lockres->l_lock, flags);
1673 #ifdef CONFIG_DEBUG_LOCK_ALLOC
1674         if (lockres->l_lockdep_map.key != NULL)
1675                 rwsem_release(&lockres->l_lockdep_map, 1, caller_ip);
1676 #endif
1677 }
1678 
1679 static int ocfs2_create_new_lock(struct ocfs2_super *osb,
1680                                  struct ocfs2_lock_res *lockres,
1681                                  int ex,
1682                                  int local)
1683 {
1684         int level =  ex ? DLM_LOCK_EX : DLM_LOCK_PR;
1685         unsigned long flags;
1686         u32 lkm_flags = local ? DLM_LKF_LOCAL : 0;
1687 
1688         spin_lock_irqsave(&lockres->l_lock, flags);
1689         BUG_ON(lockres->l_flags & OCFS2_LOCK_ATTACHED);
1690         lockres_or_flags(lockres, OCFS2_LOCK_LOCAL);
1691         spin_unlock_irqrestore(&lockres->l_lock, flags);
1692 
1693         return ocfs2_lock_create(osb, lockres, level, lkm_flags);
1694 }
1695 
1696 /* Grants us an EX lock on the data and metadata resources, skipping
1697  * the normal cluster directory lookup. Use this ONLY on newly created
1698  * inodes which other nodes can't possibly see, and which haven't been
1699  * hashed in the inode hash yet. This can give us a good performance
1700  * increase as it'll skip the network broadcast normally associated
1701  * with creating a new lock resource. */
1702 int ocfs2_create_new_inode_locks(struct inode *inode)
1703 {
1704         int ret;
1705         struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
1706 
1707         BUG_ON(!ocfs2_inode_is_new(inode));
1708 
1709         mlog(0, "Inode %llu\n", (unsigned long long)OCFS2_I(inode)->ip_blkno);
1710 
1711         /* NOTE: That we don't increment any of the holder counts, nor
1712          * do we add anything to a journal handle. Since this is
1713          * supposed to be a new inode which the cluster doesn't know
1714          * about yet, there is no need to.  As far as the LVB handling
1715          * is concerned, this is basically like acquiring an EX lock
1716          * on a resource which has an invalid one -- we'll set it
1717          * valid when we release the EX. */
1718 
1719         ret = ocfs2_create_new_lock(osb, &OCFS2_I(inode)->ip_rw_lockres, 1, 1);
1720         if (ret) {
1721                 mlog_errno(ret);
1722                 goto bail;
1723         }
1724 
1725         /*
1726          * We don't want to use DLM_LKF_LOCAL on a meta data lock as they
1727          * don't use a generation in their lock names.
1728          */
1729         ret = ocfs2_create_new_lock(osb, &OCFS2_I(inode)->ip_inode_lockres, 1, 0);
1730         if (ret) {
1731                 mlog_errno(ret);
1732                 goto bail;
1733         }
1734 
1735         ret = ocfs2_create_new_lock(osb, &OCFS2_I(inode)->ip_open_lockres, 0, 0);
1736         if (ret)
1737                 mlog_errno(ret);
1738 
1739 bail:
1740         return ret;
1741 }
1742 
1743 int ocfs2_rw_lock(struct inode *inode, int write)
1744 {
1745         int status, level;
1746         struct ocfs2_lock_res *lockres;
1747         struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
1748 
1749         mlog(0, "inode %llu take %s RW lock\n",
1750              (unsigned long long)OCFS2_I(inode)->ip_blkno,
1751              write ? "EXMODE" : "PRMODE");
1752 
1753         if (ocfs2_mount_local(osb))
1754                 return 0;
1755 
1756         lockres = &OCFS2_I(inode)->ip_rw_lockres;
1757 
1758         level = write ? DLM_LOCK_EX : DLM_LOCK_PR;
1759 
1760         status = ocfs2_cluster_lock(osb, lockres, level, 0, 0);
1761         if (status < 0)
1762                 mlog_errno(status);
1763 
1764         return status;
1765 }
1766 
1767 int ocfs2_try_rw_lock(struct inode *inode, int write)
1768 {
1769         int status, level;
1770         struct ocfs2_lock_res *lockres;
1771         struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
1772 
1773         mlog(0, "inode %llu try to take %s RW lock\n",
1774              (unsigned long long)OCFS2_I(inode)->ip_blkno,
1775              write ? "EXMODE" : "PRMODE");
1776 
1777         if (ocfs2_mount_local(osb))
1778                 return 0;
1779 
1780         lockres = &OCFS2_I(inode)->ip_rw_lockres;
1781 
1782         level = write ? DLM_LOCK_EX : DLM_LOCK_PR;
1783 
1784         status = ocfs2_cluster_lock(osb, lockres, level, DLM_LKF_NOQUEUE, 0);
1785         return status;
1786 }
1787 
1788 void ocfs2_rw_unlock(struct inode *inode, int write)
1789 {
1790         int level = write ? DLM_LOCK_EX : DLM_LOCK_PR;
1791         struct ocfs2_lock_res *lockres = &OCFS2_I(inode)->ip_rw_lockres;
1792         struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
1793 
1794         mlog(0, "inode %llu drop %s RW lock\n",
1795              (unsigned long long)OCFS2_I(inode)->ip_blkno,
1796              write ? "EXMODE" : "PRMODE");
1797 
1798         if (!ocfs2_mount_local(osb))
1799                 ocfs2_cluster_unlock(osb, lockres, level);
1800 }
1801 
1802 /*
1803  * ocfs2_open_lock always get PR mode lock.
1804  */
1805 int ocfs2_open_lock(struct inode *inode)
1806 {
1807         int status = 0;
1808         struct ocfs2_lock_res *lockres;
1809         struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
1810 
1811         mlog(0, "inode %llu take PRMODE open lock\n",
1812              (unsigned long long)OCFS2_I(inode)->ip_blkno);
1813 
1814         if (ocfs2_is_hard_readonly(osb) || ocfs2_mount_local(osb))
1815                 goto out;
1816 
1817         lockres = &OCFS2_I(inode)->ip_open_lockres;
1818 
1819         status = ocfs2_cluster_lock(osb, lockres, DLM_LOCK_PR, 0, 0);
1820         if (status < 0)
1821                 mlog_errno(status);
1822 
1823 out:
1824         return status;
1825 }
1826 
1827 int ocfs2_try_open_lock(struct inode *inode, int write)
1828 {
1829         int status = 0, level;
1830         struct ocfs2_lock_res *lockres;
1831         struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
1832 
1833         mlog(0, "inode %llu try to take %s open lock\n",
1834              (unsigned long long)OCFS2_I(inode)->ip_blkno,
1835              write ? "EXMODE" : "PRMODE");
1836 
1837         if (ocfs2_is_hard_readonly(osb)) {
1838                 if (write)
1839                         status = -EROFS;
1840                 goto out;
1841         }
1842 
1843         if (ocfs2_mount_local(osb))
1844                 goto out;
1845 
1846         lockres = &OCFS2_I(inode)->ip_open_lockres;
1847 
1848         level = write ? DLM_LOCK_EX : DLM_LOCK_PR;
1849 
1850         /*
1851          * The file system may already holding a PRMODE/EXMODE open lock.
1852          * Since we pass DLM_LKF_NOQUEUE, the request won't block waiting on
1853          * other nodes and the -EAGAIN will indicate to the caller that
1854          * this inode is still in use.
1855          */
1856         status = ocfs2_cluster_lock(osb, lockres, level, DLM_LKF_NOQUEUE, 0);
1857 
1858 out:
1859         return status;
1860 }
1861 
1862 /*
1863  * ocfs2_open_unlock unlock PR and EX mode open locks.
1864  */
1865 void ocfs2_open_unlock(struct inode *inode)
1866 {
1867         struct ocfs2_lock_res *lockres = &OCFS2_I(inode)->ip_open_lockres;
1868         struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
1869 
1870         mlog(0, "inode %llu drop open lock\n",
1871              (unsigned long long)OCFS2_I(inode)->ip_blkno);
1872 
1873         if (ocfs2_mount_local(osb))
1874                 goto out;
1875 
1876         if(lockres->l_ro_holders)
1877                 ocfs2_cluster_unlock(osb, lockres, DLM_LOCK_PR);
1878         if(lockres->l_ex_holders)
1879                 ocfs2_cluster_unlock(osb, lockres, DLM_LOCK_EX);
1880 
1881 out:
1882         return;
1883 }
1884 
1885 static int ocfs2_flock_handle_signal(struct ocfs2_lock_res *lockres,
1886                                      int level)
1887 {
1888         int ret;
1889         struct ocfs2_super *osb = ocfs2_get_lockres_osb(lockres);
1890         unsigned long flags;
1891         struct ocfs2_mask_waiter mw;
1892 
1893         ocfs2_init_mask_waiter(&mw);
1894 
1895 retry_cancel:
1896         spin_lock_irqsave(&lockres->l_lock, flags);
1897         if (lockres->l_flags & OCFS2_LOCK_BUSY) {
1898                 ret = ocfs2_prepare_cancel_convert(osb, lockres);
1899                 if (ret) {
1900                         spin_unlock_irqrestore(&lockres->l_lock, flags);
1901                         ret = ocfs2_cancel_convert(osb, lockres);
1902                         if (ret < 0) {
1903                                 mlog_errno(ret);
1904                                 goto out;
1905                         }
1906                         goto retry_cancel;
1907                 }
1908                 lockres_add_mask_waiter(lockres, &mw, OCFS2_LOCK_BUSY, 0);
1909                 spin_unlock_irqrestore(&lockres->l_lock, flags);
1910 
1911                 ocfs2_wait_for_mask(&mw);
1912                 goto retry_cancel;
1913         }
1914 
1915         ret = -ERESTARTSYS;
1916         /*
1917          * We may still have gotten the lock, in which case there's no
1918          * point to restarting the syscall.
1919          */
1920         if (lockres->l_level == level)
1921                 ret = 0;
1922 
1923         mlog(0, "Cancel returning %d. flags: 0x%lx, level: %d, act: %d\n", ret,
1924              lockres->l_flags, lockres->l_level, lockres->l_action);
1925 
1926         spin_unlock_irqrestore(&lockres->l_lock, flags);
1927 
1928 out:
1929         return ret;
1930 }
1931 
1932 /*
1933  * ocfs2_file_lock() and ocfs2_file_unlock() map to a single pair of
1934  * flock() calls. The locking approach this requires is sufficiently
1935  * different from all other cluster lock types that we implement a
1936  * separate path to the "low-level" dlm calls. In particular:
1937  *
1938  * - No optimization of lock levels is done - we take at exactly
1939  *   what's been requested.
1940  *
1941  * - No lock caching is employed. We immediately downconvert to
1942  *   no-lock at unlock time. This also means flock locks never go on
1943  *   the blocking list).
1944  *
1945  * - Since userspace can trivially deadlock itself with flock, we make
1946  *   sure to allow cancellation of a misbehaving applications flock()
1947  *   request.
1948  *
1949  * - Access to any flock lockres doesn't require concurrency, so we
1950  *   can simplify the code by requiring the caller to guarantee
1951  *   serialization of dlmglue flock calls.
1952  */
1953 int ocfs2_file_lock(struct file *file, int ex, int trylock)
1954 {
1955         int ret, level = ex ? DLM_LOCK_EX : DLM_LOCK_PR;
1956         unsigned int lkm_flags = trylock ? DLM_LKF_NOQUEUE : 0;
1957         unsigned long flags;
1958         struct ocfs2_file_private *fp = file->private_data;
1959         struct ocfs2_lock_res *lockres = &fp->fp_flock;
1960         struct ocfs2_super *osb = OCFS2_SB(file->f_mapping->host->i_sb);
1961         struct ocfs2_mask_waiter mw;
1962 
1963         ocfs2_init_mask_waiter(&mw);
1964 
1965         if ((lockres->l_flags & OCFS2_LOCK_BUSY) ||
1966             (lockres->l_level > DLM_LOCK_NL)) {
1967                 mlog(ML_ERROR,
1968                      "File lock \"%s\" has busy or locked state: flags: 0x%lx, "
1969                      "level: %u\n", lockres->l_name, lockres->l_flags,
1970                      lockres->l_level);
1971                 return -EINVAL;
1972         }
1973 
1974         spin_lock_irqsave(&lockres->l_lock, flags);
1975         if (!(lockres->l_flags & OCFS2_LOCK_ATTACHED)) {
1976                 lockres_add_mask_waiter(lockres, &mw, OCFS2_LOCK_BUSY, 0);
1977                 spin_unlock_irqrestore(&lockres->l_lock, flags);
1978 
1979                 /*
1980                  * Get the lock at NLMODE to start - that way we
1981                  * can cancel the upconvert request if need be.
1982                  */
1983                 ret = ocfs2_lock_create(osb, lockres, DLM_LOCK_NL, 0);
1984                 if (ret < 0) {
1985                         mlog_errno(ret);
1986                         goto out;
1987                 }
1988 
1989                 ret = ocfs2_wait_for_mask(&mw);
1990                 if (ret) {
1991                         mlog_errno(ret);
1992                         goto out;
1993                 }
1994                 spin_lock_irqsave(&lockres->l_lock, flags);
1995         }
1996 
1997         lockres->l_action = OCFS2_AST_CONVERT;
1998         lkm_flags |= DLM_LKF_CONVERT;
1999         lockres->l_requested = level;
2000         lockres_or_flags(lockres, OCFS2_LOCK_BUSY);
2001 
2002         lockres_add_mask_waiter(lockres, &mw, OCFS2_LOCK_BUSY, 0);
2003         spin_unlock_irqrestore(&lockres->l_lock, flags);
2004 
2005         ret = ocfs2_dlm_lock(osb->cconn, level, &lockres->l_lksb, lkm_flags,
2006                              lockres->l_name, OCFS2_LOCK_ID_MAX_LEN - 1);
2007         if (ret) {
2008                 if (!trylock || (ret != -EAGAIN)) {
2009                         ocfs2_log_dlm_error("ocfs2_dlm_lock", ret, lockres);
2010                         ret = -EINVAL;
2011                 }
2012 
2013                 ocfs2_recover_from_dlm_error(lockres, 1);
2014                 lockres_remove_mask_waiter(lockres, &mw);
2015                 goto out;
2016         }
2017 
2018         ret = ocfs2_wait_for_mask_interruptible(&mw, lockres);
2019         if (ret == -ERESTARTSYS) {
2020                 /*
2021                  * Userspace can cause deadlock itself with
2022                  * flock(). Current behavior locally is to allow the
2023                  * deadlock, but abort the system call if a signal is
2024                  * received. We follow this example, otherwise a
2025                  * poorly written program could sit in kernel until
2026                  * reboot.
2027                  *
2028                  * Handling this is a bit more complicated for Ocfs2
2029                  * though. We can't exit this function with an
2030                  * outstanding lock request, so a cancel convert is
2031                  * required. We intentionally overwrite 'ret' - if the
2032                  * cancel fails and the lock was granted, it's easier
2033                  * to just bubble success back up to the user.
2034                  */
2035                 ret = ocfs2_flock_handle_signal(lockres, level);
2036         } else if (!ret && (level > lockres->l_level)) {
2037                 /* Trylock failed asynchronously */
2038                 BUG_ON(!trylock);
2039                 ret = -EAGAIN;
2040         }
2041 
2042 out:
2043 
2044         mlog(0, "Lock: \"%s\" ex: %d, trylock: %d, returns: %d\n",
2045              lockres->l_name, ex, trylock, ret);
2046         return ret;
2047 }
2048 
2049 void ocfs2_file_unlock(struct file *file)
2050 {
2051         int ret;
2052         unsigned int gen;
2053         unsigned long flags;
2054         struct ocfs2_file_private *fp = file->private_data;
2055         struct ocfs2_lock_res *lockres = &fp->fp_flock;
2056         struct ocfs2_super *osb = OCFS2_SB(file->f_mapping->host->i_sb);
2057         struct ocfs2_mask_waiter mw;
2058 
2059         ocfs2_init_mask_waiter(&mw);
2060 
2061         if (!(lockres->l_flags & OCFS2_LOCK_ATTACHED))
2062                 return;
2063 
2064         if (lockres->l_level == DLM_LOCK_NL)
2065                 return;
2066 
2067         mlog(0, "Unlock: \"%s\" flags: 0x%lx, level: %d, act: %d\n",
2068              lockres->l_name, lockres->l_flags, lockres->l_level,
2069              lockres->l_action);
2070 
2071         spin_lock_irqsave(&lockres->l_lock, flags);
2072         /*
2073          * Fake a blocking ast for the downconvert code.
2074          */
2075         lockres_or_flags(lockres, OCFS2_LOCK_BLOCKED);
2076         lockres->l_blocking = DLM_LOCK_EX;
2077 
2078         gen = ocfs2_prepare_downconvert(lockres, DLM_LOCK_NL);
2079         lockres_add_mask_waiter(lockres, &mw, OCFS2_LOCK_BUSY, 0);
2080         spin_unlock_irqrestore(&lockres->l_lock, flags);
2081 
2082         ret = ocfs2_downconvert_lock(osb, lockres, DLM_LOCK_NL, 0, gen);
2083         if (ret) {
2084                 mlog_errno(ret);
2085                 return;
2086         }
2087 
2088         ret = ocfs2_wait_for_mask(&mw);
2089         if (ret)
2090                 mlog_errno(ret);
2091 }
2092 
2093 static void ocfs2_downconvert_on_unlock(struct ocfs2_super *osb,
2094                                         struct ocfs2_lock_res *lockres)
2095 {
2096         int kick = 0;
2097 
2098         /* If we know that another node is waiting on our lock, kick
2099          * the downconvert thread * pre-emptively when we reach a release
2100          * condition. */
2101         if (lockres->l_flags & OCFS2_LOCK_BLOCKED) {
2102                 switch(lockres->l_blocking) {
2103                 case DLM_LOCK_EX:
2104                         if (!lockres->l_ex_holders && !lockres->l_ro_holders)
2105                                 kick = 1;
2106                         break;
2107                 case DLM_LOCK_PR:
2108                         if (!lockres->l_ex_holders)
2109                                 kick = 1;
2110                         break;
2111                 default:
2112                         BUG();
2113                 }
2114         }
2115 
2116         if (kick)
2117                 ocfs2_wake_downconvert_thread(osb);
2118 }
2119 
2120 #define OCFS2_SEC_BITS   34
2121 #define OCFS2_SEC_SHIFT  (64 - 34)
2122 #define OCFS2_NSEC_MASK  ((1ULL << OCFS2_SEC_SHIFT) - 1)
2123 
2124 /* LVB only has room for 64 bits of time here so we pack it for
2125  * now. */
2126 static u64 ocfs2_pack_timespec(struct timespec64 *spec)
2127 {
2128         u64 res;
2129         u64 sec = clamp_t(time64_t, spec->tv_sec, 0, 0x3ffffffffull);
2130         u32 nsec = spec->tv_nsec;
2131 
2132         res = (sec << OCFS2_SEC_SHIFT) | (nsec & OCFS2_NSEC_MASK);
2133 
2134         return res;
2135 }
2136 
2137 /* Call this with the lockres locked. I am reasonably sure we don't
2138  * need ip_lock in this function as anyone who would be changing those
2139  * values is supposed to be blocked in ocfs2_inode_lock right now. */
2140 static void __ocfs2_stuff_meta_lvb(struct inode *inode)
2141 {
2142         struct ocfs2_inode_info *oi = OCFS2_I(inode);
2143         struct ocfs2_lock_res *lockres = &oi->ip_inode_lockres;
2144         struct ocfs2_meta_lvb *lvb;
2145 
2146         lvb = ocfs2_dlm_lvb(&lockres->l_lksb);
2147 
2148         /*
2149          * Invalidate the LVB of a deleted inode - this way other
2150          * nodes are forced to go to disk and discover the new inode
2151          * status.
2152          */
2153         if (oi->ip_flags & OCFS2_INODE_DELETED) {
2154                 lvb->lvb_version = 0;
2155                 goto out;
2156         }
2157 
2158         lvb->lvb_version   = OCFS2_LVB_VERSION;
2159         lvb->lvb_isize     = cpu_to_be64(i_size_read(inode));
2160         lvb->lvb_iclusters = cpu_to_be32(oi->ip_clusters);
2161         lvb->lvb_iuid      = cpu_to_be32(i_uid_read(inode));
2162         lvb->lvb_igid      = cpu_to_be32(i_gid_read(inode));
2163         lvb->lvb_imode     = cpu_to_be16(inode->i_mode);
2164         lvb->lvb_inlink    = cpu_to_be16(inode->i_nlink);
2165         lvb->lvb_iatime_packed  =
2166                 cpu_to_be64(ocfs2_pack_timespec(&inode->i_atime));
2167         lvb->lvb_ictime_packed =
2168                 cpu_to_be64(ocfs2_pack_timespec(&inode->i_ctime));
2169         lvb->lvb_imtime_packed =
2170                 cpu_to_be64(ocfs2_pack_timespec(&inode->i_mtime));
2171         lvb->lvb_iattr    = cpu_to_be32(oi->ip_attr);
2172         lvb->lvb_idynfeatures = cpu_to_be16(oi->ip_dyn_features);
2173         lvb->lvb_igeneration = cpu_to_be32(inode->i_generation);
2174 
2175 out:
2176         mlog_meta_lvb(0, lockres);
2177 }
2178 
2179 static void ocfs2_unpack_timespec(struct timespec64 *spec,
2180                                   u64 packed_time)
2181 {
2182         spec->tv_sec = packed_time >> OCFS2_SEC_SHIFT;
2183         spec->tv_nsec = packed_time & OCFS2_NSEC_MASK;
2184 }
2185 
2186 static void ocfs2_refresh_inode_from_lvb(struct inode *inode)
2187 {
2188         struct ocfs2_inode_info *oi = OCFS2_I(inode);
2189         struct ocfs2_lock_res *lockres = &oi->ip_inode_lockres;
2190         struct ocfs2_meta_lvb *lvb;
2191 
2192         mlog_meta_lvb(0, lockres);
2193 
2194         lvb = ocfs2_dlm_lvb(&lockres->l_lksb);
2195 
2196         /* We're safe here without the lockres lock... */
2197         spin_lock(&oi->ip_lock);
2198         oi->ip_clusters = be32_to_cpu(lvb->lvb_iclusters);
2199         i_size_write(inode, be64_to_cpu(lvb->lvb_isize));
2200 
2201         oi->ip_attr = be32_to_cpu(lvb->lvb_iattr);
2202         oi->ip_dyn_features = be16_to_cpu(lvb->lvb_idynfeatures);
2203         ocfs2_set_inode_flags(inode);
2204 
2205         /* fast-symlinks are a special case */
2206         if (S_ISLNK(inode->i_mode) && !oi->ip_clusters)
2207                 inode->i_blocks = 0;
2208         else
2209                 inode->i_blocks = ocfs2_inode_sector_count(inode);
2210 
2211         i_uid_write(inode, be32_to_cpu(lvb->lvb_iuid));
2212         i_gid_write(inode, be32_to_cpu(lvb->lvb_igid));
2213         inode->i_mode    = be16_to_cpu(lvb->lvb_imode);
2214         set_nlink(inode, be16_to_cpu(lvb->lvb_inlink));
2215         ocfs2_unpack_timespec(&inode->i_atime,
2216                               be64_to_cpu(lvb->lvb_iatime_packed));
2217         ocfs2_unpack_timespec(&inode->i_mtime,
2218                               be64_to_cpu(lvb->lvb_imtime_packed));
2219         ocfs2_unpack_timespec(&inode->i_ctime,
2220                               be64_to_cpu(lvb->lvb_ictime_packed));
2221         spin_unlock(&oi->ip_lock);
2222 }
2223 
2224 static inline int ocfs2_meta_lvb_is_trustable(struct inode *inode,
2225                                               struct ocfs2_lock_res *lockres)
2226 {
2227         struct ocfs2_meta_lvb *lvb = ocfs2_dlm_lvb(&lockres->l_lksb);
2228 
2229         if (ocfs2_dlm_lvb_valid(&lockres->l_lksb)
2230             && lvb->lvb_version == OCFS2_LVB_VERSION
2231             && be32_to_cpu(lvb->lvb_igeneration) == inode->i_generation)
2232                 return 1;
2233         return 0;
2234 }
2235 
2236 /* Determine whether a lock resource needs to be refreshed, and
2237  * arbitrate who gets to refresh it.
2238  *
2239  *   0 means no refresh needed.
2240  *
2241  *   > 0 means you need to refresh this and you MUST call
2242  *   ocfs2_complete_lock_res_refresh afterwards. */
2243 static int ocfs2_should_refresh_lock_res(struct ocfs2_lock_res *lockres)
2244 {
2245         unsigned long flags;
2246         int status = 0;
2247 
2248 refresh_check:
2249         spin_lock_irqsave(&lockres->l_lock, flags);
2250         if (!(lockres->l_flags & OCFS2_LOCK_NEEDS_REFRESH)) {
2251                 spin_unlock_irqrestore(&lockres->l_lock, flags);
2252                 goto bail;
2253         }
2254 
2255         if (lockres->l_flags & OCFS2_LOCK_REFRESHING) {
2256                 spin_unlock_irqrestore(&lockres->l_lock, flags);
2257 
2258                 ocfs2_wait_on_refreshing_lock(lockres);
2259                 goto refresh_check;
2260         }
2261 
2262         /* Ok, I'll be the one to refresh this lock. */
2263         lockres_or_flags(lockres, OCFS2_LOCK_REFRESHING);
2264         spin_unlock_irqrestore(&lockres->l_lock, flags);
2265 
2266         status = 1;
2267 bail:
2268         mlog(0, "status %d\n", status);
2269         return status;
2270 }
2271 
2272 /* If status is non zero, I'll mark it as not being in refresh
2273  * anymroe, but i won't clear the needs refresh flag. */
2274 static inline void ocfs2_complete_lock_res_refresh(struct ocfs2_lock_res *lockres,
2275                                                    int status)
2276 {
2277         unsigned long flags;
2278 
2279         spin_lock_irqsave(&lockres->l_lock, flags);
2280         lockres_clear_flags(lockres, OCFS2_LOCK_REFRESHING);
2281         if (!status)
2282                 lockres_clear_flags(lockres, OCFS2_LOCK_NEEDS_REFRESH);
2283         spin_unlock_irqrestore(&lockres->l_lock, flags);
2284 
2285         wake_up(&lockres->l_event);
2286 }
2287 
2288 /* may or may not return a bh if it went to disk. */
2289 static int ocfs2_inode_lock_update(struct inode *inode,
2290                                   struct buffer_head **bh)
2291 {
2292         int status = 0;
2293         struct ocfs2_inode_info *oi = OCFS2_I(inode);
2294         struct ocfs2_lock_res *lockres = &oi->ip_inode_lockres;
2295         struct ocfs2_dinode *fe;
2296         struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
2297 
2298         if (ocfs2_mount_local(osb))
2299                 goto bail;
2300 
2301         spin_lock(&oi->ip_lock);
2302         if (oi->ip_flags & OCFS2_INODE_DELETED) {
2303                 mlog(0, "Orphaned inode %llu was deleted while we "
2304                      "were waiting on a lock. ip_flags = 0x%x\n",
2305                      (unsigned long long)oi->ip_blkno, oi->ip_flags);
2306                 spin_unlock(&oi->ip_lock);
2307                 status = -ENOENT;
2308                 goto bail;
2309         }
2310         spin_unlock(&oi->ip_lock);
2311 
2312         if (!ocfs2_should_refresh_lock_res(lockres))
2313                 goto bail;
2314 
2315         /* This will discard any caching information we might have had
2316          * for the inode metadata. */
2317         ocfs2_metadata_cache_purge(INODE_CACHE(inode));
2318 
2319         ocfs2_extent_map_trunc(inode, 0);
2320 
2321         if (ocfs2_meta_lvb_is_trustable(inode, lockres)) {
2322                 mlog(0, "Trusting LVB on inode %llu\n",
2323                      (unsigned long long)oi->ip_blkno);
2324                 ocfs2_refresh_inode_from_lvb(inode);
2325         } else {
2326                 /* Boo, we have to go to disk. */
2327                 /* read bh, cast, ocfs2_refresh_inode */
2328                 status = ocfs2_read_inode_block(inode, bh);
2329                 if (status < 0) {
2330                         mlog_errno(status);
2331                         goto bail_refresh;
2332                 }
2333                 fe = (struct ocfs2_dinode *) (*bh)->b_data;
2334 
2335                 /* This is a good chance to make sure we're not
2336                  * locking an invalid object.  ocfs2_read_inode_block()
2337                  * already checked that the inode block is sane.
2338                  *
2339                  * We bug on a stale inode here because we checked
2340                  * above whether it was wiped from disk. The wiping
2341                  * node provides a guarantee that we receive that
2342                  * message and can mark the inode before dropping any
2343                  * locks associated with it. */
2344                 mlog_bug_on_msg(inode->i_generation !=
2345                                 le32_to_cpu(fe->i_generation),
2346                                 "Invalid dinode %llu disk generation: %u "
2347                                 "inode->i_generation: %u\n",
2348                                 (unsigned long long)oi->ip_blkno,
2349                                 le32_to_cpu(fe->i_generation),
2350                                 inode->i_generation);
2351                 mlog_bug_on_msg(le64_to_cpu(fe->i_dtime) ||
2352                                 !(fe->i_flags & cpu_to_le32(OCFS2_VALID_FL)),
2353                                 "Stale dinode %llu dtime: %llu flags: 0x%x\n",
2354                                 (unsigned long long)oi->ip_blkno,
2355                                 (unsigned long long)le64_to_cpu(fe->i_dtime),
2356                                 le32_to_cpu(fe->i_flags));
2357 
2358                 ocfs2_refresh_inode(inode, fe);
2359                 ocfs2_track_lock_refresh(lockres);
2360         }
2361 
2362         status = 0;
2363 bail_refresh:
2364         ocfs2_complete_lock_res_refresh(lockres, status);
2365 bail:
2366         return status;
2367 }
2368 
2369 static int ocfs2_assign_bh(struct inode *inode,
2370                            struct buffer_head **ret_bh,
2371                            struct buffer_head *passed_bh)
2372 {
2373         int status;
2374 
2375         if (passed_bh) {
2376                 /* Ok, the update went to disk for us, use the
2377                  * returned bh. */
2378                 *ret_bh = passed_bh;
2379                 get_bh(*ret_bh);
2380 
2381                 return 0;
2382         }
2383 
2384         status = ocfs2_read_inode_block(inode, ret_bh);
2385         if (status < 0)
2386                 mlog_errno(status);
2387 
2388         return status;
2389 }
2390 
2391 /*
2392  * returns < 0 error if the callback will never be called, otherwise
2393  * the result of the lock will be communicated via the callback.
2394  */
2395 int ocfs2_inode_lock_full_nested(struct inode *inode,
2396                                  struct buffer_head **ret_bh,
2397                                  int ex,
2398                                  int arg_flags,
2399                                  int subclass)
2400 {
2401         int status, level, acquired;
2402         u32 dlm_flags;
2403         struct ocfs2_lock_res *lockres = NULL;
2404         struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
2405         struct buffer_head *local_bh = NULL;
2406 
2407         mlog(0, "inode %llu, take %s META lock\n",
2408              (unsigned long long)OCFS2_I(inode)->ip_blkno,
2409              ex ? "EXMODE" : "PRMODE");
2410 
2411         status = 0;
2412         acquired = 0;
2413         /* We'll allow faking a readonly metadata lock for
2414          * rodevices. */
2415         if (ocfs2_is_hard_readonly(osb)) {
2416                 if (ex)
2417                         status = -EROFS;
2418                 goto getbh;
2419         }
2420 
2421         if ((arg_flags & OCFS2_META_LOCK_GETBH) ||
2422             ocfs2_mount_local(osb))
2423                 goto update;
2424 
2425         if (!(arg_flags & OCFS2_META_LOCK_RECOVERY))
2426                 ocfs2_wait_for_recovery(osb);
2427 
2428         lockres = &OCFS2_I(inode)->ip_inode_lockres;
2429         level = ex ? DLM_LOCK_EX : DLM_LOCK_PR;
2430         dlm_flags = 0;
2431         if (arg_flags & OCFS2_META_LOCK_NOQUEUE)
2432                 dlm_flags |= DLM_LKF_NOQUEUE;
2433 
2434         status = __ocfs2_cluster_lock(osb, lockres, level, dlm_flags,
2435                                       arg_flags, subclass, _RET_IP_);
2436         if (status < 0) {
2437                 if (status != -EAGAIN)
2438                         mlog_errno(status);
2439                 goto bail;
2440         }
2441 
2442         /* Notify the error cleanup path to drop the cluster lock. */
2443         acquired = 1;
2444 
2445         /* We wait twice because a node may have died while we were in
2446          * the lower dlm layers. The second time though, we've
2447          * committed to owning this lock so we don't allow signals to
2448          * abort the operation. */
2449         if (!(arg_flags & OCFS2_META_LOCK_RECOVERY))
2450                 ocfs2_wait_for_recovery(osb);
2451 
2452 update:
2453         /*
2454          * We only see this flag if we're being called from
2455          * ocfs2_read_locked_inode(). It means we're locking an inode
2456          * which hasn't been populated yet, so clear the refresh flag
2457          * and let the caller handle it.
2458          */
2459         if (inode->i_state & I_NEW) {
2460                 status = 0;
2461                 if (lockres)
2462                         ocfs2_complete_lock_res_refresh(lockres, 0);
2463                 goto bail;
2464         }
2465 
2466         /* This is fun. The caller may want a bh back, or it may
2467          * not. ocfs2_inode_lock_update definitely wants one in, but
2468          * may or may not read one, depending on what's in the
2469          * LVB. The result of all of this is that we've *only* gone to
2470          * disk if we have to, so the complexity is worthwhile. */
2471         status = ocfs2_inode_lock_update(inode, &local_bh);
2472         if (status < 0) {
2473                 if (status != -ENOENT)
2474                         mlog_errno(status);
2475                 goto bail;
2476         }
2477 getbh:
2478         if (ret_bh) {
2479                 status = ocfs2_assign_bh(inode, ret_bh, local_bh);
2480                 if (status < 0) {
2481                         mlog_errno(status);
2482                         goto bail;
2483                 }
2484         }
2485 
2486 bail:
2487         if (status < 0) {
2488                 if (ret_bh && (*ret_bh)) {
2489                         brelse(*ret_bh);
2490                         *ret_bh = NULL;
2491                 }
2492                 if (acquired)
2493                         ocfs2_inode_unlock(inode, ex);
2494         }
2495 
2496         if (local_bh)
2497                 brelse(local_bh);
2498 
2499         return status;
2500 }
2501 
2502 /*
2503  * This is working around a lock inversion between tasks acquiring DLM
2504  * locks while holding a page lock and the downconvert thread which
2505  * blocks dlm lock acquiry while acquiring page locks.
2506  *
2507  * ** These _with_page variantes are only intended to be called from aop
2508  * methods that hold page locks and return a very specific *positive* error
2509  * code that aop methods pass up to the VFS -- test for errors with != 0. **
2510  *
2511  * The DLM is called such that it returns -EAGAIN if it would have
2512  * blocked waiting for the downconvert thread.  In that case we unlock
2513  * our page so the downconvert thread can make progress.  Once we've
2514  * done this we have to return AOP_TRUNCATED_PAGE so the aop method
2515  * that called us can bubble that back up into the VFS who will then
2516  * immediately retry the aop call.
2517  */
2518 int ocfs2_inode_lock_with_page(struct inode *inode,
2519                               struct buffer_head **ret_bh,
2520                               int ex,
2521                               struct page *page)
2522 {
2523         int ret;
2524 
2525         ret = ocfs2_inode_lock_full(inode, ret_bh, ex, OCFS2_LOCK_NONBLOCK);
2526         if (ret == -EAGAIN) {
2527                 unlock_page(page);
2528                 /*
2529                  * If we can't get inode lock immediately, we should not return
2530                  * directly here, since this will lead to a softlockup problem.
2531                  * The method is to get a blocking lock and immediately unlock
2532                  * before returning, this can avoid CPU resource waste due to
2533                  * lots of retries, and benefits fairness in getting lock.
2534                  */
2535                 if (ocfs2_inode_lock(inode, ret_bh, ex) == 0)
2536                         ocfs2_inode_unlock(inode, ex);
2537                 ret = AOP_TRUNCATED_PAGE;
2538         }
2539 
2540         return ret;
2541 }
2542 
2543 int ocfs2_inode_lock_atime(struct inode *inode,
2544                           struct vfsmount *vfsmnt,
2545                           int *level, int wait)
2546 {
2547         int ret;
2548 
2549         if (wait)
2550                 ret = ocfs2_inode_lock(inode, NULL, 0);
2551         else
2552                 ret = ocfs2_try_inode_lock(inode, NULL, 0);
2553 
2554         if (ret < 0) {
2555                 if (ret != -EAGAIN)
2556                         mlog_errno(ret);
2557                 return ret;
2558         }
2559 
2560         /*
2561          * If we should update atime, we will get EX lock,
2562          * otherwise we just get PR lock.
2563          */
2564         if (ocfs2_should_update_atime(inode, vfsmnt)) {
2565                 struct buffer_head *bh = NULL;
2566 
2567                 ocfs2_inode_unlock(inode, 0);
2568                 if (wait)
2569                         ret = ocfs2_inode_lock(inode, &bh, 1);
2570                 else
2571                         ret = ocfs2_try_inode_lock(inode, &bh, 1);
2572 
2573                 if (ret < 0) {
2574                         if (ret != -EAGAIN)
2575                                 mlog_errno(ret);
2576                         return ret;
2577                 }
2578                 *level = 1;
2579                 if (ocfs2_should_update_atime(inode, vfsmnt))
2580                         ocfs2_update_inode_atime(inode, bh);
2581                 if (bh)
2582                         brelse(bh);
2583         } else
2584                 *level = 0;
2585 
2586         return ret;
2587 }
2588 
2589 void ocfs2_inode_unlock(struct inode *inode,
2590                        int ex)
2591 {
2592         int level = ex ? DLM_LOCK_EX : DLM_LOCK_PR;
2593         struct ocfs2_lock_res *lockres = &OCFS2_I(inode)->ip_inode_lockres;
2594         struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
2595 
2596         mlog(0, "inode %llu drop %s META lock\n",
2597              (unsigned long long)OCFS2_I(inode)->ip_blkno,
2598              ex ? "EXMODE" : "PRMODE");
2599 
2600         if (!ocfs2_is_hard_readonly(osb) &&
2601             !ocfs2_mount_local(osb))
2602                 ocfs2_cluster_unlock(osb, lockres, level);
2603 }
2604 
2605 /*
2606  * This _tracker variantes are introduced to deal with the recursive cluster
2607  * locking issue. The idea is to keep track of a lock holder on the stack of
2608  * the current process. If there's a lock holder on the stack, we know the
2609  * task context is already protected by cluster locking. Currently, they're
2610  * used in some VFS entry routines.
2611  *
2612  * return < 0 on error, return == 0 if there's no lock holder on the stack
2613  * before this call, return == 1 if this call would be a recursive locking.
2614  * return == -1 if this lock attempt will cause an upgrade which is forbidden.
2615  *
2616  * When taking lock levels into account,we face some different situations.
2617  *
2618  * 1. no lock is held
2619  *    In this case, just lock the inode as requested and return 0
2620  *
2621  * 2. We are holding a lock
2622  *    For this situation, things diverges into several cases
2623  *
2624  *    wanted     holding             what to do
2625  *    ex                ex          see 2.1 below
2626  *    ex                pr          see 2.2 below
2627  *    pr                ex          see 2.1 below
2628  *    pr                pr          see 2.1 below
2629  *
2630  *    2.1 lock level that is been held is compatible
2631  *    with the wanted level, so no lock action will be tacken.
2632  *
2633  *    2.2 Otherwise, an upgrade is needed, but it is forbidden.
2634  *
2635  * Reason why upgrade within a process is forbidden is that
2636  * lock upgrade may cause dead lock. The following illustrates
2637  * how it happens.
2638  *
2639  *         thread on node1                             thread on node2
2640  * ocfs2_inode_lock_tracker(ex=0)
2641  *
2642  *                                <======   ocfs2_inode_lock_tracker(ex=1)
2643  *
2644  * ocfs2_inode_lock_tracker(ex=1)
2645  */
2646 int ocfs2_inode_lock_tracker(struct inode *inode,
2647                              struct buffer_head **ret_bh,
2648                              int ex,
2649                              struct ocfs2_lock_holder *oh)
2650 {
2651         int status = 0;
2652         struct ocfs2_lock_res *lockres;
2653         struct ocfs2_lock_holder *tmp_oh;
2654         struct pid *pid = task_pid(current);
2655 
2656 
2657         lockres = &OCFS2_I(inode)->ip_inode_lockres;
2658         tmp_oh = ocfs2_pid_holder(lockres, pid);
2659 
2660         if (!tmp_oh) {
2661                 /*
2662                  * This corresponds to the case 1.
2663                  * We haven't got any lock before.
2664                  */
2665                 status = ocfs2_inode_lock_full(inode, ret_bh, ex, 0);
2666                 if (status < 0) {
2667                         if (status != -ENOENT)
2668                                 mlog_errno(status);
2669                         return status;
2670                 }
2671 
2672                 oh->oh_ex = ex;
2673                 ocfs2_add_holder(lockres, oh);
2674                 return 0;
2675         }
2676 
2677         if (unlikely(ex && !tmp_oh->oh_ex)) {
2678                 /*
2679                  * case 2.2 upgrade may cause dead lock, forbid it.
2680                  */
2681                 mlog(ML_ERROR, "Recursive locking is not permitted to "
2682                      "upgrade to EX level from PR level.\n");
2683                 dump_stack();
2684                 return -EINVAL;
2685         }
2686 
2687         /*
2688          *  case 2.1 OCFS2_META_LOCK_GETBH flag make ocfs2_inode_lock_full.
2689          *  ignore the lock level and just update it.
2690          */
2691         if (ret_bh) {
2692                 status = ocfs2_inode_lock_full(inode, ret_bh, ex,
2693                                                OCFS2_META_LOCK_GETBH);
2694                 if (status < 0) {
2695                         if (status != -ENOENT)
2696                                 mlog_errno(status);
2697                         return status;
2698                 }
2699         }
2700         return tmp_oh ? 1 : 0;
2701 }
2702 
2703 void ocfs2_inode_unlock_tracker(struct inode *inode,
2704                                 int ex,
2705                                 struct ocfs2_lock_holder *oh,
2706                                 int had_lock)
2707 {
2708         struct ocfs2_lock_res *lockres;
2709 
2710         lockres = &OCFS2_I(inode)->ip_inode_lockres;
2711         /* had_lock means that the currect process already takes the cluster
2712          * lock previously.
2713          * If had_lock is 1, we have nothing to do here.
2714          * If had_lock is 0, we will release the lock.
2715          */
2716         if (!had_lock) {
2717                 ocfs2_inode_unlock(inode, oh->oh_ex);
2718                 ocfs2_remove_holder(lockres, oh);
2719         }
2720 }
2721 
2722 int ocfs2_orphan_scan_lock(struct ocfs2_super *osb, u32 *seqno)
2723 {
2724         struct ocfs2_lock_res *lockres;
2725         struct ocfs2_orphan_scan_lvb *lvb;
2726         int status = 0;
2727 
2728         if (ocfs2_is_hard_readonly(osb))
2729                 return -EROFS;
2730 
2731         if (ocfs2_mount_local(osb))
2732                 return 0;
2733 
2734         lockres = &osb->osb_orphan_scan.os_lockres;
2735         status = ocfs2_cluster_lock(osb, lockres, DLM_LOCK_EX, 0, 0);
2736         if (status < 0)
2737                 return status;
2738 
2739         lvb = ocfs2_dlm_lvb(&lockres->l_lksb);
2740         if (ocfs2_dlm_lvb_valid(&lockres->l_lksb) &&
2741             lvb->lvb_version == OCFS2_ORPHAN_LVB_VERSION)
2742                 *seqno = be32_to_cpu(lvb->lvb_os_seqno);
2743         else
2744                 *seqno = osb->osb_orphan_scan.os_seqno + 1;
2745 
2746         return status;
2747 }
2748 
2749 void ocfs2_orphan_scan_unlock(struct ocfs2_super *osb, u32 seqno)
2750 {
2751         struct ocfs2_lock_res *lockres;
2752         struct ocfs2_orphan_scan_lvb *lvb;
2753 
2754         if (!ocfs2_is_hard_readonly(osb) && !ocfs2_mount_local(osb)) {
2755                 lockres = &osb->osb_orphan_scan.os_lockres;
2756                 lvb = ocfs2_dlm_lvb(&lockres->l_lksb);
2757                 lvb->lvb_version = OCFS2_ORPHAN_LVB_VERSION;
2758                 lvb->lvb_os_seqno = cpu_to_be32(seqno);
2759                 ocfs2_cluster_unlock(osb, lockres, DLM_LOCK_EX);
2760         }
2761 }
2762 
2763 int ocfs2_super_lock(struct ocfs2_super *osb,
2764                      int ex)
2765 {
2766         int status = 0;
2767         int level = ex ? DLM_LOCK_EX : DLM_LOCK_PR;
2768         struct ocfs2_lock_res *lockres = &osb->osb_super_lockres;
2769 
2770         if (ocfs2_is_hard_readonly(osb))
2771                 return -EROFS;
2772 
2773         if (ocfs2_mount_local(osb))
2774                 goto bail;
2775 
2776         status = ocfs2_cluster_lock(osb, lockres, level, 0, 0);
2777         if (status < 0) {
2778                 mlog_errno(status);
2779                 goto bail;
2780         }
2781 
2782         /* The super block lock path is really in the best position to
2783          * know when resources covered by the lock need to be
2784          * refreshed, so we do it here. Of course, making sense of
2785          * everything is up to the caller :) */
2786         status = ocfs2_should_refresh_lock_res(lockres);
2787         if (status) {
2788                 status = ocfs2_refresh_slot_info(osb);
2789 
2790                 ocfs2_complete_lock_res_refresh(lockres, status);
2791 
2792                 if (status < 0) {
2793                         ocfs2_cluster_unlock(osb, lockres, level);
2794                         mlog_errno(status);
2795                 }
2796                 ocfs2_track_lock_refresh(lockres);
2797         }
2798 bail:
2799         return status;
2800 }
2801 
2802 void ocfs2_super_unlock(struct ocfs2_super *osb,
2803                         int ex)
2804 {
2805         int level = ex ? DLM_LOCK_EX : DLM_LOCK_PR;
2806         struct ocfs2_lock_res *lockres = &osb->osb_super_lockres;
2807 
2808         if (!ocfs2_mount_local(osb))
2809                 ocfs2_cluster_unlock(osb, lockres, level);
2810 }
2811 
2812 int ocfs2_rename_lock(struct ocfs2_super *osb)
2813 {
2814         int status;
2815         struct ocfs2_lock_res *lockres = &osb->osb_rename_lockres;
2816 
2817         if (ocfs2_is_hard_readonly(osb))
2818                 return -EROFS;
2819 
2820         if (ocfs2_mount_local(osb))
2821                 return 0;
2822 
2823         status = ocfs2_cluster_lock(osb, lockres, DLM_LOCK_EX, 0, 0);
2824         if (status < 0)
2825                 mlog_errno(status);
2826 
2827         return status;
2828 }
2829 
2830 void ocfs2_rename_unlock(struct ocfs2_super *osb)
2831 {
2832         struct ocfs2_lock_res *lockres = &osb->osb_rename_lockres;
2833 
2834         if (!ocfs2_mount_local(osb))
2835                 ocfs2_cluster_unlock(osb, lockres, DLM_LOCK_EX);
2836 }
2837 
2838 int ocfs2_nfs_sync_lock(struct ocfs2_super *osb, int ex)
2839 {
2840         int status;
2841         struct ocfs2_lock_res *lockres = &osb->osb_nfs_sync_lockres;
2842 
2843         if (ocfs2_is_hard_readonly(osb))
2844                 return -EROFS;
2845 
2846         if (ocfs2_mount_local(osb))
2847                 return 0;
2848 
2849         status = ocfs2_cluster_lock(osb, lockres, ex ? LKM_EXMODE : LKM_PRMODE,
2850                                     0, 0);
2851         if (status < 0)
2852                 mlog(ML_ERROR, "lock on nfs sync lock failed %d\n", status);
2853 
2854         return status;
2855 }
2856 
2857 void ocfs2_nfs_sync_unlock(struct ocfs2_super *osb, int ex)
2858 {
2859         struct ocfs2_lock_res *lockres = &osb->osb_nfs_sync_lockres;
2860 
2861         if (!ocfs2_mount_local(osb))
2862                 ocfs2_cluster_unlock(osb, lockres,
2863                                      ex ? LKM_EXMODE : LKM_PRMODE);
2864 }
2865 
2866 int ocfs2_trim_fs_lock(struct ocfs2_super *osb,
2867                        struct ocfs2_trim_fs_info *info, int trylock)
2868 {
2869         int status;
2870         struct ocfs2_trim_fs_lvb *lvb;
2871         struct ocfs2_lock_res *lockres = &osb->osb_trim_fs_lockres;
2872 
2873         if (info)
2874                 info->tf_valid = 0;
2875 
2876         if (ocfs2_is_hard_readonly(osb))
2877                 return -EROFS;
2878 
2879         if (ocfs2_mount_local(osb))
2880                 return 0;
2881 
2882         status = ocfs2_cluster_lock(osb, lockres, DLM_LOCK_EX,
2883                                     trylock ? DLM_LKF_NOQUEUE : 0, 0);
2884         if (status < 0) {
2885                 if (status != -EAGAIN)
2886                         mlog_errno(status);
2887                 return status;
2888         }
2889 
2890         if (info) {
2891                 lvb = ocfs2_dlm_lvb(&lockres->l_lksb);
2892                 if (ocfs2_dlm_lvb_valid(&lockres->l_lksb) &&
2893                     lvb->lvb_version == OCFS2_TRIMFS_LVB_VERSION) {
2894                         info->tf_valid = 1;
2895                         info->tf_success = lvb->lvb_success;
2896                         info->tf_nodenum = be32_to_cpu(lvb->lvb_nodenum);
2897                         info->tf_start = be64_to_cpu(lvb->lvb_start);
2898                         info->tf_len = be64_to_cpu(lvb->lvb_len);
2899                         info->tf_minlen = be64_to_cpu(lvb->lvb_minlen);
2900                         info->tf_trimlen = be64_to_cpu(lvb->lvb_trimlen);
2901                 }
2902         }
2903 
2904         return status;
2905 }
2906 
2907 void ocfs2_trim_fs_unlock(struct ocfs2_super *osb,
2908                           struct ocfs2_trim_fs_info *info)
2909 {
2910         struct ocfs2_trim_fs_lvb *lvb;
2911         struct ocfs2_lock_res *lockres = &osb->osb_trim_fs_lockres;
2912 
2913         if (ocfs2_mount_local(osb))
2914                 return;
2915 
2916         if (info) {
2917                 lvb = ocfs2_dlm_lvb(&lockres->l_lksb);
2918                 lvb->lvb_version = OCFS2_TRIMFS_LVB_VERSION;
2919                 lvb->lvb_success = info->tf_success;
2920                 lvb->lvb_nodenum = cpu_to_be32(info->tf_nodenum);
2921                 lvb->lvb_start = cpu_to_be64(info->tf_start);
2922                 lvb->lvb_len = cpu_to_be64(info->tf_len);
2923                 lvb->lvb_minlen = cpu_to_be64(info->tf_minlen);
2924                 lvb->lvb_trimlen = cpu_to_be64(info->tf_trimlen);
2925         }
2926 
2927         ocfs2_cluster_unlock(osb, lockres, DLM_LOCK_EX);
2928 }
2929 
2930 int ocfs2_dentry_lock(struct dentry *dentry, int ex)
2931 {
2932         int ret;
2933         int level = ex ? DLM_LOCK_EX : DLM_LOCK_PR;
2934         struct ocfs2_dentry_lock *dl = dentry->d_fsdata;
2935         struct ocfs2_super *osb = OCFS2_SB(dentry->d_sb);
2936 
2937         BUG_ON(!dl);
2938 
2939         if (ocfs2_is_hard_readonly(osb)) {
2940                 if (ex)
2941                         return -EROFS;
2942                 return 0;
2943         }
2944 
2945         if (ocfs2_mount_local(osb))
2946                 return 0;
2947 
2948         ret = ocfs2_cluster_lock(osb, &dl->dl_lockres, level, 0, 0);
2949         if (ret < 0)
2950                 mlog_errno(ret);
2951 
2952         return ret;
2953 }
2954 
2955 void ocfs2_dentry_unlock(struct dentry *dentry, int ex)
2956 {
2957         int level = ex ? DLM_LOCK_EX : DLM_LOCK_PR;
2958         struct ocfs2_dentry_lock *dl = dentry->d_fsdata;
2959         struct ocfs2_super *osb = OCFS2_SB(dentry->d_sb);
2960 
2961         if (!ocfs2_is_hard_readonly(osb) && !ocfs2_mount_local(osb))
2962                 ocfs2_cluster_unlock(osb, &dl->dl_lockres, level);
2963 }
2964 
2965 /* Reference counting of the dlm debug structure. We want this because
2966  * open references on the debug inodes can live on after a mount, so
2967  * we can't rely on the ocfs2_super to always exist. */
2968 static void ocfs2_dlm_debug_free(struct kref *kref)
2969 {
2970         struct ocfs2_dlm_debug *dlm_debug;
2971 
2972         dlm_debug = container_of(kref, struct ocfs2_dlm_debug, d_refcnt);
2973 
2974         kfree(dlm_debug);
2975 }
2976 
2977 void ocfs2_put_dlm_debug(struct ocfs2_dlm_debug *dlm_debug)
2978 {
2979         if (dlm_debug)
2980                 kref_put(&dlm_debug->d_refcnt, ocfs2_dlm_debug_free);
2981 }
2982 
2983 static void ocfs2_get_dlm_debug(struct ocfs2_dlm_debug *debug)
2984 {
2985         kref_get(&debug->d_refcnt);
2986 }
2987 
2988 struct ocfs2_dlm_debug *ocfs2_new_dlm_debug(void)
2989 {
2990         struct ocfs2_dlm_debug *dlm_debug;
2991 
2992         dlm_debug = kmalloc(sizeof(struct ocfs2_dlm_debug), GFP_KERNEL);
2993         if (!dlm_debug) {
2994                 mlog_errno(-ENOMEM);
2995                 goto out;
2996         }
2997 
2998         kref_init(&dlm_debug->d_refcnt);
2999         INIT_LIST_HEAD(&dlm_debug->d_lockres_tracking);
3000         dlm_debug->d_locking_state = NULL;
3001 out:
3002         return dlm_debug;
3003 }
3004 
3005 /* Access to this is arbitrated for us via seq_file->sem. */
3006 struct ocfs2_dlm_seq_priv {
3007         struct ocfs2_dlm_debug *p_dlm_debug;
3008         struct ocfs2_lock_res p_iter_res;
3009         struct ocfs2_lock_res p_tmp_res;
3010 };
3011 
3012 static struct ocfs2_lock_res *ocfs2_dlm_next_res(struct ocfs2_lock_res *start,
3013                                                  struct ocfs2_dlm_seq_priv *priv)
3014 {
3015         struct ocfs2_lock_res *iter, *ret = NULL;
3016         struct ocfs2_dlm_debug *dlm_debug = priv->p_dlm_debug;
3017 
3018         assert_spin_locked(&ocfs2_dlm_tracking_lock);
3019 
3020         list_for_each_entry(iter, &start->l_debug_list, l_debug_list) {
3021                 /* discover the head of the list */
3022                 if (&iter->l_debug_list == &dlm_debug->d_lockres_tracking) {
3023                         mlog(0, "End of list found, %p\n", ret);
3024                         break;
3025                 }
3026 
3027                 /* We track our "dummy" iteration lockres' by a NULL
3028                  * l_ops field. */
3029                 if (iter->l_ops != NULL) {
3030                         ret = iter;
3031                         break;
3032                 }
3033         }
3034 
3035         return ret;
3036 }
3037 
3038 static void *ocfs2_dlm_seq_start(struct seq_file *m, loff_t *pos)
3039 {
3040         struct ocfs2_dlm_seq_priv *priv = m->private;
3041         struct ocfs2_lock_res *iter;
3042 
3043         spin_lock(&ocfs2_dlm_tracking_lock);
3044         iter = ocfs2_dlm_next_res(&priv->p_iter_res, priv);
3045         if (iter) {
3046                 /* Since lockres' have the lifetime of their container
3047                  * (which can be inodes, ocfs2_supers, etc) we want to
3048                  * copy this out to a temporary lockres while still
3049                  * under the spinlock. Obviously after this we can't
3050                  * trust any pointers on the copy returned, but that's
3051                  * ok as the information we want isn't typically held
3052                  * in them. */
3053                 priv->p_tmp_res = *iter;
3054                 iter = &priv->p_tmp_res;
3055         }
3056         spin_unlock(&ocfs2_dlm_tracking_lock);
3057 
3058         return iter;
3059 }
3060 
3061 static void ocfs2_dlm_seq_stop(struct seq_file *m, void *v)
3062 {
3063 }
3064 
3065 static void *ocfs2_dlm_seq_next(struct seq_file *m, void *v, loff_t *pos)
3066 {
3067         struct ocfs2_dlm_seq_priv *priv = m->private;
3068         struct ocfs2_lock_res *iter = v;
3069         struct ocfs2_lock_res *dummy = &priv->p_iter_res;
3070 
3071         spin_lock(&ocfs2_dlm_tracking_lock);
3072         iter = ocfs2_dlm_next_res(iter, priv);
3073         list_del_init(&dummy->l_debug_list);
3074         if (iter) {
3075                 list_add(&dummy->l_debug_list, &iter->l_debug_list);
3076                 priv->p_tmp_res = *iter;
3077                 iter = &priv->p_tmp_res;
3078         }
3079         spin_unlock(&ocfs2_dlm_tracking_lock);
3080 
3081         return iter;
3082 }
3083 
3084 /*
3085  * Version is used by debugfs.ocfs2 to determine the format being used
3086  *
3087  * New in version 2
3088  *      - Lock stats printed
3089  * New in version 3
3090  *      - Max time in lock stats is in usecs (instead of nsecs)
3091  */
3092 #define OCFS2_DLM_DEBUG_STR_VERSION 3
3093 static int ocfs2_dlm_seq_show(struct seq_file *m, void *v)
3094 {
3095         int i;
3096         char *lvb;
3097         struct ocfs2_lock_res *lockres = v;
3098 
3099         if (!lockres)
3100                 return -EINVAL;
3101 
3102         seq_printf(m, "0x%x\t", OCFS2_DLM_DEBUG_STR_VERSION);
3103 
3104         if (lockres->l_type == OCFS2_LOCK_TYPE_DENTRY)
3105                 seq_printf(m, "%.*s%08x\t", OCFS2_DENTRY_LOCK_INO_START - 1,
3106                            lockres->l_name,
3107                            (unsigned int)ocfs2_get_dentry_lock_ino(lockres));
3108         else
3109                 seq_printf(m, "%.*s\t", OCFS2_LOCK_ID_MAX_LEN, lockres->l_name);
3110 
3111         seq_printf(m, "%d\t"
3112                    "0x%lx\t"
3113                    "0x%x\t"
3114                    "0x%x\t"
3115                    "%u\t"
3116                    "%u\t"
3117                    "%d\t"
3118                    "%d\t",
3119                    lockres->l_level,
3120                    lockres->l_flags,
3121                    lockres->l_action,
3122                    lockres->l_unlock_action,
3123                    lockres->l_ro_holders,
3124                    lockres->l_ex_holders,
3125                    lockres->l_requested,
3126                    lockres->l_blocking);
3127 
3128         /* Dump the raw LVB */
3129         lvb = ocfs2_dlm_lvb(&lockres->l_lksb);
3130         for(i = 0; i < DLM_LVB_LEN; i++)
3131                 seq_printf(m, "0x%x\t", lvb[i]);
3132 
3133 #ifdef CONFIG_OCFS2_FS_STATS
3134 # define lock_num_prmode(_l)            ((_l)->l_lock_prmode.ls_gets)
3135 # define lock_num_exmode(_l)            ((_l)->l_lock_exmode.ls_gets)
3136 # define lock_num_prmode_failed(_l)     ((_l)->l_lock_prmode.ls_fail)
3137 # define lock_num_exmode_failed(_l)     ((_l)->l_lock_exmode.ls_fail)
3138 # define lock_total_prmode(_l)          ((_l)->l_lock_prmode.ls_total)
3139 # define lock_total_exmode(_l)          ((_l)->l_lock_exmode.ls_total)
3140 # define lock_max_prmode(_l)            ((_l)->l_lock_prmode.ls_max)
3141 # define lock_max_exmode(_l)            ((_l)->l_lock_exmode.ls_max)
3142 # define lock_refresh(_l)               ((_l)->l_lock_refresh)
3143 #else
3144 # define lock_num_prmode(_l)            (0)
3145 # define lock_num_exmode(_l)            (0)
3146 # define lock_num_prmode_failed(_l)     (0)
3147 # define lock_num_exmode_failed(_l)     (0)
3148 # define lock_total_prmode(_l)          (0ULL)
3149 # define lock_total_exmode(_l)          (0ULL)
3150 # define lock_max_prmode(_l)            (0)
3151 # define lock_max_exmode(_l)            (0)
3152 # define lock_refresh(_l)               (0)
3153 #endif
3154         /* The following seq_print was added in version 2 of this output */
3155         seq_printf(m, "%u\t"
3156                    "%u\t"
3157                    "%u\t"
3158                    "%u\t"
3159                    "%llu\t"
3160                    "%llu\t"
3161                    "%u\t"
3162                    "%u\t"
3163                    "%u\t",
3164                    lock_num_prmode(lockres),
3165                    lock_num_exmode(lockres),
3166                    lock_num_prmode_failed(lockres),
3167                    lock_num_exmode_failed(lockres),
3168                    lock_total_prmode(lockres),
3169                    lock_total_exmode(lockres),
3170                    lock_max_prmode(lockres),
3171                    lock_max_exmode(lockres),
3172                    lock_refresh(lockres));
3173 
3174         /* End the line */
3175         seq_printf(m, "\n");
3176         return 0;
3177 }
3178 
3179 static const struct seq_operations ocfs2_dlm_seq_ops = {
3180         .start =        ocfs2_dlm_seq_start,
3181         .stop =         ocfs2_dlm_seq_stop,
3182         .next =         ocfs2_dlm_seq_next,
3183         .show =         ocfs2_dlm_seq_show,
3184 };
3185 
3186 static int ocfs2_dlm_debug_release(struct inode *inode, struct file *file)
3187 {
3188         struct seq_file *seq = file->private_data;
3189         struct ocfs2_dlm_seq_priv *priv = seq->private;
3190         struct ocfs2_lock_res *res = &priv->p_iter_res;
3191 
3192         ocfs2_remove_lockres_tracking(res);
3193         ocfs2_put_dlm_debug(priv->p_dlm_debug);
3194         return seq_release_private(inode, file);
3195 }
3196 
3197 static int ocfs2_dlm_debug_open(struct inode *inode, struct file *file)
3198 {
3199         struct ocfs2_dlm_seq_priv *priv;
3200         struct ocfs2_super *osb;
3201 
3202         priv = __seq_open_private(file, &ocfs2_dlm_seq_ops, sizeof(*priv));
3203         if (!priv) {
3204                 mlog_errno(-ENOMEM);
3205                 return -ENOMEM;
3206         }
3207 
3208         osb = inode->i_private;
3209         ocfs2_get_dlm_debug(osb->osb_dlm_debug);
3210         priv->p_dlm_debug = osb->osb_dlm_debug;
3211         INIT_LIST_HEAD(&priv->p_iter_res.l_debug_list);
3212 
3213         ocfs2_add_lockres_tracking(&priv->p_iter_res,
3214                                    priv->p_dlm_debug);
3215 
3216         return 0;
3217 }
3218 
3219 static const struct file_operations ocfs2_dlm_debug_fops = {
3220         .open =         ocfs2_dlm_debug_open,
3221         .release =      ocfs2_dlm_debug_release,
3222         .read =         seq_read,
3223         .llseek =       seq_lseek,
3224 };
3225 
3226 static int ocfs2_dlm_init_debug(struct ocfs2_super *osb)
3227 {
3228         int ret = 0;
3229         struct ocfs2_dlm_debug *dlm_debug = osb->osb_dlm_debug;
3230 
3231         dlm_debug->d_locking_state = debugfs_create_file("locking_state",
3232                                                          S_IFREG|S_IRUSR,
3233                                                          osb->osb_debug_root,
3234                                                          osb,
3235                                                          &ocfs2_dlm_debug_fops);
3236         if (!dlm_debug->d_locking_state) {
3237                 ret = -EINVAL;
3238                 mlog(ML_ERROR,
3239                      "Unable to create locking state debugfs file.\n");
3240                 goto out;
3241         }
3242 
3243         ocfs2_get_dlm_debug(dlm_debug);
3244 out:
3245         return ret;
3246 }
3247 
3248 static void ocfs2_dlm_shutdown_debug(struct ocfs2_super *osb)
3249 {
3250         struct ocfs2_dlm_debug *dlm_debug = osb->osb_dlm_debug;
3251 
3252         if (dlm_debug) {
3253                 debugfs_remove(dlm_debug->d_locking_state);
3254                 ocfs2_put_dlm_debug(dlm_debug);
3255         }
3256 }
3257 
3258 int ocfs2_dlm_init(struct ocfs2_super *osb)
3259 {
3260         int status = 0;
3261         struct ocfs2_cluster_connection *conn = NULL;
3262 
3263         if (ocfs2_mount_local(osb)) {
3264                 osb->node_num = 0;
3265                 goto local;
3266         }
3267 
3268         status = ocfs2_dlm_init_debug(osb);
3269         if (status < 0) {
3270                 mlog_errno(status);
3271                 goto bail;
3272         }
3273 
3274         /* launch downconvert thread */
3275         osb->dc_task = kthread_run(ocfs2_downconvert_thread, osb, "ocfs2dc-%s",
3276                         osb->uuid_str);
3277         if (IS_ERR(osb->dc_task)) {
3278                 status = PTR_ERR(osb->dc_task);
3279                 osb->dc_task = NULL;
3280                 mlog_errno(status);
3281                 goto bail;
3282         }
3283 
3284         /* for now, uuid == domain */
3285         status = ocfs2_cluster_connect(osb->osb_cluster_stack,
3286                                        osb->osb_cluster_name,
3287                                        strlen(osb->osb_cluster_name),
3288                                        osb->uuid_str,
3289                                        strlen(osb->uuid_str),
3290                                        &lproto, ocfs2_do_node_down, osb,
3291                                        &conn);
3292         if (status) {
3293                 mlog_errno(status);
3294                 goto bail;
3295         }
3296 
3297         status = ocfs2_cluster_this_node(conn, &osb->node_num);
3298         if (status < 0) {
3299                 mlog_errno(status);
3300                 mlog(ML_ERROR,
3301                      "could not find this host's node number\n");
3302                 ocfs2_cluster_disconnect(conn, 0);
3303                 goto bail;
3304         }
3305 
3306 local:
3307         ocfs2_super_lock_res_init(&osb->osb_super_lockres, osb);
3308         ocfs2_rename_lock_res_init(&osb->osb_rename_lockres, osb);
3309         ocfs2_nfs_sync_lock_res_init(&osb->osb_nfs_sync_lockres, osb);
3310         ocfs2_orphan_scan_lock_res_init(&osb->osb_orphan_scan.os_lockres, osb);
3311 
3312         osb->cconn = conn;
3313 bail:
3314         if (status < 0) {
3315                 ocfs2_dlm_shutdown_debug(osb);
3316                 if (osb->dc_task)
3317                         kthread_stop(osb->dc_task);
3318         }
3319 
3320         return status;
3321 }
3322 
3323 void ocfs2_dlm_shutdown(struct ocfs2_super *osb,
3324                         int hangup_pending)
3325 {
3326         ocfs2_drop_osb_locks(osb);
3327 
3328         /*
3329          * Now that we have dropped all locks and ocfs2_dismount_volume()
3330          * has disabled recovery, the DLM won't be talking to us.  It's
3331          * safe to tear things down before disconnecting the cluster.
3332          */
3333 
3334         if (osb->dc_task) {
3335                 kthread_stop(osb->dc_task);
3336                 osb->dc_task = NULL;
3337         }
3338 
3339         ocfs2_lock_res_free(&osb->osb_super_lockres);
3340         ocfs2_lock_res_free(&osb->osb_rename_lockres);
3341         ocfs2_lock_res_free(&osb->osb_nfs_sync_lockres);
3342         ocfs2_lock_res_free(&osb->osb_orphan_scan.os_lockres);
3343 
3344         ocfs2_cluster_disconnect(osb->cconn, hangup_pending);
3345         osb->cconn = NULL;
3346 
3347         ocfs2_dlm_shutdown_debug(osb);
3348 }
3349 
3350 static int ocfs2_drop_lock(struct ocfs2_super *osb,
3351                            struct ocfs2_lock_res *lockres)
3352 {
3353         int ret;
3354         unsigned long flags;
3355         u32 lkm_flags = 0;
3356 
3357         /* We didn't get anywhere near actually using this lockres. */
3358         if (!(lockres->l_flags & OCFS2_LOCK_INITIALIZED))
3359                 goto out;
3360 
3361         if (lockres->l_ops->flags & LOCK_TYPE_USES_LVB)
3362                 lkm_flags |= DLM_LKF_VALBLK;
3363 
3364         spin_lock_irqsave(&lockres->l_lock, flags);
3365 
3366         mlog_bug_on_msg(!(lockres->l_flags & OCFS2_LOCK_FREEING),
3367                         "lockres %s, flags 0x%lx\n",
3368                         lockres->l_name, lockres->l_flags);
3369 
3370         while (lockres->l_flags & OCFS2_LOCK_BUSY) {
3371                 mlog(0, "waiting on busy lock \"%s\": flags = %lx, action = "
3372                      "%u, unlock_action = %u\n",
3373                      lockres->l_name, lockres->l_flags, lockres->l_action,
3374                      lockres->l_unlock_action);
3375 
3376                 spin_unlock_irqrestore(&lockres->l_lock, flags);
3377 
3378                 /* XXX: Today we just wait on any busy
3379                  * locks... Perhaps we need to cancel converts in the
3380                  * future? */
3381                 ocfs2_wait_on_busy_lock(lockres);
3382 
3383                 spin_lock_irqsave(&lockres->l_lock, flags);
3384         }
3385 
3386         if (lockres->l_ops->flags & LOCK_TYPE_USES_LVB) {
3387                 if (lockres->l_flags & OCFS2_LOCK_ATTACHED &&
3388                     lockres->l_level == DLM_LOCK_EX &&
3389                     !(lockres->l_flags & OCFS2_LOCK_NEEDS_REFRESH))
3390                         lockres->l_ops->set_lvb(lockres);
3391         }
3392 
3393         if (lockres->l_flags & OCFS2_LOCK_BUSY)
3394                 mlog(ML_ERROR, "destroying busy lock: \"%s\"\n",
3395                      lockres->l_name);
3396         if (lockres->l_flags & OCFS2_LOCK_BLOCKED)
3397                 mlog(0, "destroying blocked lock: \"%s\"\n", lockres->l_name);
3398 
3399         if (!(lockres->l_flags & OCFS2_LOCK_ATTACHED)) {
3400                 spin_unlock_irqrestore(&lockres->l_lock, flags);
3401                 goto out;
3402         }
3403 
3404         lockres_clear_flags(lockres, OCFS2_LOCK_ATTACHED);
3405 
3406         /* make sure we never get here while waiting for an ast to
3407          * fire. */
3408         BUG_ON(lockres->l_action != OCFS2_AST_INVALID);
3409 
3410         /* is this necessary? */
3411         lockres_or_flags(lockres, OCFS2_LOCK_BUSY);
3412         lockres->l_unlock_action = OCFS2_UNLOCK_DROP_LOCK;
3413         spin_unlock_irqrestore(&lockres->l_lock, flags);
3414 
3415         mlog(0, "lock %s\n", lockres->l_name);
3416 
3417         ret = ocfs2_dlm_unlock(osb->cconn, &lockres->l_lksb, lkm_flags);
3418         if (ret) {
3419                 ocfs2_log_dlm_error("ocfs2_dlm_unlock", ret, lockres);
3420                 mlog(ML_ERROR, "lockres flags: %lu\n", lockres->l_flags);
3421                 ocfs2_dlm_dump_lksb(&lockres->l_lksb);
3422                 BUG();
3423         }
3424         mlog(0, "lock %s, successful return from ocfs2_dlm_unlock\n",
3425              lockres->l_name);
3426 
3427         ocfs2_wait_on_busy_lock(lockres);
3428 out:
3429         return 0;
3430 }
3431 
3432 static void ocfs2_process_blocked_lock(struct ocfs2_super *osb,
3433                                        struct ocfs2_lock_res *lockres);
3434 
3435 /* Mark the lockres as being dropped. It will no longer be
3436  * queued if blocking, but we still may have to wait on it
3437  * being dequeued from the downconvert thread before we can consider
3438  * it safe to drop.
3439  *
3440  * You can *not* attempt to call cluster_lock on this lockres anymore. */
3441 void ocfs2_mark_lockres_freeing(struct ocfs2_super *osb,
3442                                 struct ocfs2_lock_res *lockres)
3443 {
3444         int status;
3445         struct ocfs2_mask_waiter mw;
3446         unsigned long flags, flags2;
3447 
3448         ocfs2_init_mask_waiter(&mw);
3449 
3450         spin_lock_irqsave(&lockres->l_lock, flags);
3451         lockres->l_flags |= OCFS2_LOCK_FREEING;
3452         if (lockres->l_flags & OCFS2_LOCK_QUEUED && current == osb->dc_task) {
3453                 /*
3454                  * We know the downconvert is queued but not in progress
3455                  * because we are the downconvert thread and processing
3456                  * different lock. So we can just remove the lock from the
3457                  * queue. This is not only an optimization but also a way
3458                  * to avoid the following deadlock:
3459                  *   ocfs2_dentry_post_unlock()
3460                  *     ocfs2_dentry_lock_put()
3461                  *       ocfs2_drop_dentry_lock()
3462                  *         iput()
3463                  *           ocfs2_evict_inode()
3464                  *             ocfs2_clear_inode()
3465                  *               ocfs2_mark_lockres_freeing()
3466                  *                 ... blocks waiting for OCFS2_LOCK_QUEUED
3467                  *                 since we are the downconvert thread which
3468                  *                 should clear the flag.
3469                  */
3470                 spin_unlock_irqrestore(&lockres->l_lock, flags);
3471                 spin_lock_irqsave(&osb->dc_task_lock, flags2);
3472                 list_del_init(&lockres->l_blocked_list);
3473                 osb->blocked_lock_count--;
3474                 spin_unlock_irqrestore(&osb->dc_task_lock, flags2);
3475                 /*
3476                  * Warn if we recurse into another post_unlock call.  Strictly
3477                  * speaking it isn't a problem but we need to be careful if
3478                  * that happens (stack overflow, deadlocks, ...) so warn if
3479                  * ocfs2 grows a path for which this can happen.
3480                  */
3481                 WARN_ON_ONCE(lockres->l_ops->post_unlock);
3482                 /* Since the lock is freeing we don't do much in the fn below */
3483                 ocfs2_process_blocked_lock(osb, lockres);
3484                 return;
3485         }
3486         while (lockres->l_flags & OCFS2_LOCK_QUEUED) {
3487                 lockres_add_mask_waiter(lockres, &mw, OCFS2_LOCK_QUEUED, 0);
3488                 spin_unlock_irqrestore(&lockres->l_lock, flags);
3489 
3490                 mlog(0, "Waiting on lockres %s\n", lockres->l_name);
3491 
3492                 status = ocfs2_wait_for_mask(&mw);
3493                 if (status)
3494                         mlog_errno(status);
3495 
3496                 spin_lock_irqsave(&lockres->l_lock, flags);
3497         }
3498         spin_unlock_irqrestore(&lockres->l_lock, flags);
3499 }
3500 
3501 void ocfs2_simple_drop_lockres(struct ocfs2_super *osb,
3502                                struct ocfs2_lock_res *lockres)
3503 {
3504         int ret;
3505 
3506         ocfs2_mark_lockres_freeing(osb, lockres);
3507         ret = ocfs2_drop_lock(osb, lockres);
3508         if (ret)
3509                 mlog_errno(ret);
3510 }
3511 
3512 static void ocfs2_drop_osb_locks(struct ocfs2_super *osb)
3513 {
3514         ocfs2_simple_drop_lockres(osb, &osb->osb_super_lockres);
3515         ocfs2_simple_drop_lockres(osb, &osb->osb_rename_lockres);
3516         ocfs2_simple_drop_lockres(osb, &osb->osb_nfs_sync_lockres);
3517         ocfs2_simple_drop_lockres(osb, &osb->osb_orphan_scan.os_lockres);
3518 }
3519 
3520 int ocfs2_drop_inode_locks(struct inode *inode)
3521 {
3522         int status, err;
3523 
3524         /* No need to call ocfs2_mark_lockres_freeing here -
3525          * ocfs2_clear_inode has done it for us. */
3526 
3527         err = ocfs2_drop_lock(OCFS2_SB(inode->i_sb),
3528                               &OCFS2_I(inode)->ip_open_lockres);
3529         if (err < 0)
3530                 mlog_errno(err);
3531 
3532         status = err;
3533 
3534         err = ocfs2_drop_lock(OCFS2_SB(inode->i_sb),
3535                               &OCFS2_I(inode)->ip_inode_lockres);
3536         if (err < 0)
3537                 mlog_errno(err);
3538         if (err < 0 && !status)
3539                 status = err;
3540 
3541         err = ocfs2_drop_lock(OCFS2_SB(inode->i_sb),
3542                               &OCFS2_I(inode)->ip_rw_lockres);
3543         if (err < 0)
3544                 mlog_errno(err);
3545         if (err < 0 && !status)
3546                 status = err;
3547 
3548         return status;
3549 }
3550 
3551 static unsigned int ocfs2_prepare_downconvert(struct ocfs2_lock_res *lockres,
3552                                               int new_level)
3553 {
3554         assert_spin_locked(&lockres->l_lock);
3555 
3556         BUG_ON(lockres->l_blocking <= DLM_LOCK_NL);
3557 
3558         if (lockres->l_level <= new_level) {
3559                 mlog(ML_ERROR, "lockres %s, lvl %d <= %d, blcklst %d, mask %d, "
3560                      "type %d, flags 0x%lx, hold %d %d, act %d %d, req %d, "
3561                      "block %d, pgen %d\n", lockres->l_name, lockres->l_level,
3562                      new_level, list_empty(&lockres->l_blocked_list),
3563                      list_empty(&lockres->l_mask_waiters), lockres->l_type,
3564                      lockres->l_flags, lockres->l_ro_holders,
3565                      lockres->l_ex_holders, lockres->l_action,
3566                      lockres->l_unlock_action, lockres->l_requested,
3567                      lockres->l_blocking, lockres->l_pending_gen);
3568                 BUG();
3569         }
3570 
3571         mlog(ML_BASTS, "lockres %s, level %d => %d, blocking %d\n",
3572              lockres->l_name, lockres->l_level, new_level, lockres->l_blocking);
3573 
3574         lockres->l_action = OCFS2_AST_DOWNCONVERT;
3575         lockres->l_requested = new_level;
3576         lockres_or_flags(lockres, OCFS2_LOCK_BUSY);
3577         return lockres_set_pending(lockres);
3578 }
3579 
3580 static int ocfs2_downconvert_lock(struct ocfs2_super *osb,
3581                                   struct ocfs2_lock_res *lockres,
3582                                   int new_level,
3583                                   int lvb,
3584                                   unsigned int generation)
3585 {
3586         int ret;
3587         u32 dlm_flags = DLM_LKF_CONVERT;
3588 
3589         mlog(ML_BASTS, "lockres %s, level %d => %d\n", lockres->l_name,
3590              lockres->l_level, new_level);
3591 
3592         /*
3593          * On DLM_LKF_VALBLK, fsdlm behaves differently with o2cb. It always
3594          * expects DLM_LKF_VALBLK being set if the LKB has LVB, so that
3595          * we can recover correctly from node failure. Otherwise, we may get
3596          * invalid LVB in LKB, but without DLM_SBF_VALNOTVALID being set.
3597          */
3598         if (ocfs2_userspace_stack(osb) &&
3599             lockres->l_ops->flags & LOCK_TYPE_USES_LVB)
3600                 lvb = 1;
3601 
3602         if (lvb)
3603                 dlm_flags |= DLM_LKF_VALBLK;
3604 
3605         ret = ocfs2_dlm_lock(osb->cconn,
3606                              new_level,
3607                              &lockres->l_lksb,
3608                              dlm_flags,
3609                              lockres->l_name,
3610                              OCFS2_LOCK_ID_MAX_LEN - 1);
3611         lockres_clear_pending(lockres, generation, osb);
3612         if (ret) {
3613                 ocfs2_log_dlm_error("ocfs2_dlm_lock", ret, lockres);
3614                 ocfs2_recover_from_dlm_error(lockres, 1);
3615                 goto bail;
3616         }
3617 
3618         ret = 0;
3619 bail:
3620         return ret;
3621 }
3622 
3623 /* returns 1 when the caller should unlock and call ocfs2_dlm_unlock */
3624 static int ocfs2_prepare_cancel_convert(struct ocfs2_super *osb,
3625                                         struct ocfs2_lock_res *lockres)
3626 {
3627         assert_spin_locked(&lockres->l_lock);
3628 
3629         if (lockres->l_unlock_action == OCFS2_UNLOCK_CANCEL_CONVERT) {
3630                 /* If we're already trying to cancel a lock conversion
3631                  * then just drop the spinlock and allow the caller to
3632                  * requeue this lock. */
3633                 mlog(ML_BASTS, "lockres %s, skip convert\n", lockres->l_name);
3634                 return 0;
3635         }
3636 
3637         /* were we in a convert when we got the bast fire? */
3638         BUG_ON(lockres->l_action != OCFS2_AST_CONVERT &&
3639                lockres->l_action != OCFS2_AST_DOWNCONVERT);
3640         /* set things up for the unlockast to know to just
3641          * clear out the ast_action and unset busy, etc. */
3642         lockres->l_unlock_action = OCFS2_UNLOCK_CANCEL_CONVERT;
3643 
3644         mlog_bug_on_msg(!(lockres->l_flags & OCFS2_LOCK_BUSY),
3645                         "lock %s, invalid flags: 0x%lx\n",
3646                         lockres->l_name, lockres->l_flags);
3647 
3648         mlog(ML_BASTS, "lockres %s\n", lockres->l_name);
3649 
3650         return 1;
3651 }
3652 
3653 static int ocfs2_cancel_convert(struct ocfs2_super *osb,
3654                                 struct ocfs2_lock_res *lockres)
3655 {
3656         int ret;
3657 
3658         ret = ocfs2_dlm_unlock(osb->cconn, &lockres->l_lksb,
3659                                DLM_LKF_CANCEL);
3660         if (ret) {
3661                 ocfs2_log_dlm_error("ocfs2_dlm_unlock", ret, lockres);
3662                 ocfs2_recover_from_dlm_error(lockres, 0);
3663         }
3664 
3665         mlog(ML_BASTS, "lockres %s\n", lockres->l_name);
3666 
3667         return ret;
3668 }
3669 
3670 static int ocfs2_unblock_lock(struct ocfs2_super *osb,
3671                               struct ocfs2_lock_res *lockres,
3672                               struct ocfs2_unblock_ctl *ctl)
3673 {
3674         unsigned long flags;
3675         int blocking;
3676         int new_level;
3677         int level;
3678         int ret = 0;
3679         int set_lvb = 0;
3680         unsigned int gen;
3681 
3682         spin_lock_irqsave(&lockres->l_lock, flags);
3683 
3684 recheck:
3685         /*
3686          * Is it still blocking? If not, we have no more work to do.
3687          */
3688         if (!(lockres->l_flags & OCFS2_LOCK_BLOCKED)) {
3689                 BUG_ON(lockres->l_blocking != DLM_LOCK_NL);
3690                 spin_unlock_irqrestore(&lockres->l_lock, flags);
3691                 ret = 0;
3692                 goto leave;
3693         }
3694 
3695         if (lockres->l_flags & OCFS2_LOCK_BUSY) {
3696                 /* XXX
3697                  * This is a *big* race.  The OCFS2_LOCK_PENDING flag
3698                  * exists entirely for one reason - another thread has set
3699                  * OCFS2_LOCK_BUSY, but has *NOT* yet called dlm_lock().
3700                  *
3701                  * If we do ocfs2_cancel_convert() before the other thread
3702                  * calls dlm_lock(), our cancel will do nothing.  We will
3703                  * get no ast, and we will have no way of knowing the
3704                  * cancel failed.  Meanwhile, the other thread will call
3705                  * into dlm_lock() and wait...forever.
3706                  *
3707                  * Why forever?  Because another node has asked for the
3708                  * lock first; that's why we're here in unblock_lock().
3709                  *
3710                  * The solution is OCFS2_LOCK_PENDING.  When PENDING is
3711                  * set, we just requeue the unblock.  Only when the other
3712                  * thread has called dlm_lock() and cleared PENDING will
3713                  * we then cancel their request.
3714                  *
3715                  * All callers of dlm_lock() must set OCFS2_DLM_PENDING
3716                  * at the same time they set OCFS2_DLM_BUSY.  They must
3717                  * clear OCFS2_DLM_PENDING after dlm_lock() returns.
3718                  */
3719                 if (lockres->l_flags & OCFS2_LOCK_PENDING) {
3720                         mlog(ML_BASTS, "lockres %s, ReQ: Pending\n",
3721                              lockres->l_name);
3722                         goto leave_requeue;
3723                 }
3724 
3725                 ctl->requeue = 1;
3726                 ret = ocfs2_prepare_cancel_convert(osb, lockres);
3727                 spin_unlock_irqrestore(&lockres->l_lock, flags);
3728                 if (ret) {
3729                         ret = ocfs2_cancel_convert(osb, lockres);
3730                         if (ret < 0)
3731                                 mlog_errno(ret);
3732                 }
3733                 goto leave;
3734         }
3735 
3736         /*
3737          * This prevents livelocks. OCFS2_LOCK_UPCONVERT_FINISHING flag is
3738          * set when the ast is received for an upconvert just before the
3739          * OCFS2_LOCK_BUSY flag is cleared. Now if the fs received a bast
3740          * on the heels of the ast, we want to delay the downconvert just
3741          * enough to allow the up requestor to do its task. Because this
3742          * lock is in the blocked queue, the lock will be downconverted
3743          * as soon as the requestor is done with the lock.
3744          */
3745         if (lockres->l_flags & OCFS2_LOCK_UPCONVERT_FINISHING)
3746                 goto leave_requeue;
3747 
3748         /*
3749          * How can we block and yet be at NL?  We were trying to upconvert
3750          * from NL and got canceled.  The code comes back here, and now
3751          * we notice and clear BLOCKING.
3752          */
3753         if (lockres->l_level == DLM_LOCK_NL) {
3754                 BUG_ON(lockres->l_ex_holders || lockres->l_ro_holders);
3755                 mlog(ML_BASTS, "lockres %s, Aborting dc\n", lockres->l_name);
3756                 lockres->l_blocking = DLM_LOCK_NL;
3757                 lockres_clear_flags(lockres, OCFS2_LOCK_BLOCKED);
3758                 spin_unlock_irqrestore(&lockres->l_lock, flags);
3759                 goto leave;
3760         }
3761 
3762         /* if we're blocking an exclusive and we have *any* holders,
3763          * then requeue. */
3764         if ((lockres->l_blocking == DLM_LOCK_EX)
3765             && (lockres->l_ex_holders || lockres->l_ro_holders)) {
3766                 mlog(ML_BASTS, "lockres %s, ReQ: EX/PR Holders %u,%u\n",
3767                      lockres->l_name, lockres->l_ex_holders,
3768                      lockres->l_ro_holders);
3769                 goto leave_requeue;
3770         }
3771 
3772         /* If it's a PR we're blocking, then only
3773          * requeue if we've got any EX holders */
3774         if (lockres->l_blocking == DLM_LOCK_PR &&
3775             lockres->l_ex_holders) {
3776                 mlog(ML_BASTS, "lockres %s, ReQ: EX Holders %u\n",
3777                      lockres->l_name, lockres->l_ex_holders);
3778                 goto leave_requeue;
3779         }
3780 
3781         /*
3782          * Can we get a lock in this state if the holder counts are
3783          * zero? The meta data unblock code used to check this.
3784          */
3785         if ((lockres->l_ops->flags & LOCK_TYPE_REQUIRES_REFRESH)
3786             && (lockres->l_flags & OCFS2_LOCK_REFRESHING)) {
3787                 mlog(ML_BASTS, "lockres %s, ReQ: Lock Refreshing\n",
3788                      lockres->l_name);
3789                 goto leave_requeue;
3790         }
3791 
3792         new_level = ocfs2_highest_compat_lock_level(lockres->l_blocking);
3793 
3794         if (lockres->l_ops->check_downconvert
3795             && !lockres->l_ops->check_downconvert(lockres, new_level)) {
3796                 mlog(ML_BASTS, "lockres %s, ReQ: Checkpointing\n",
3797                      lockres->l_name);
3798                 goto leave_requeue;
3799         }
3800 
3801         /* If we get here, then we know that there are no more
3802          * incompatible holders (and anyone asking for an incompatible
3803          * lock is blocked). We can now downconvert the lock */
3804         if (!lockres->l_ops->downconvert_worker)
3805                 goto downconvert;
3806 
3807         /* Some lockres types want to do a bit of work before
3808          * downconverting a lock. Allow that here. The worker function
3809          * may sleep, so we save off a copy of what we're blocking as
3810          * it may change while we're not holding the spin lock. */
3811         blocking = lockres->l_blocking;
3812         level = lockres->l_level;
3813         spin_unlock_irqrestore(&lockres->l_lock, flags);
3814 
3815         ctl->unblock_action = lockres->l_ops->downconvert_worker(lockres, blocking);
3816 
3817         if (ctl->unblock_action == UNBLOCK_STOP_POST) {
3818                 mlog(ML_BASTS, "lockres %s, UNBLOCK_STOP_POST\n",
3819                      lockres->l_name);
3820                 goto leave;
3821         }
3822 
3823         spin_lock_irqsave(&lockres->l_lock, flags);
3824         if ((blocking != lockres->l_blocking) || (level != lockres->l_level)) {
3825                 /* If this changed underneath us, then we can't drop
3826                  * it just yet. */
3827                 mlog(ML_BASTS, "lockres %s, block=%d:%d, level=%d:%d, "
3828                      "Recheck\n", lockres->l_name, blocking,
3829                      lockres->l_blocking, level, lockres->l_level);
3830                 goto recheck;
3831         }
3832 
3833 downconvert:
3834         ctl->requeue = 0;
3835 
3836         if (lockres->l_ops->flags & LOCK_TYPE_USES_LVB) {
3837                 if (lockres->l_level == DLM_LOCK_EX)
3838                         set_lvb = 1;
3839 
3840                 /*
3841                  * We only set the lvb if the lock has been fully
3842                  * refreshed - otherwise we risk setting stale
3843                  * data. Otherwise, there's no need to actually clear
3844                  * out the lvb here as it's value is still valid.
3845                  */
3846                 if (set_lvb && !(lockres->l_flags & OCFS2_LOCK_NEEDS_REFRESH))
3847                         lockres->l_ops->set_lvb(lockres);
3848         }
3849 
3850         gen = ocfs2_prepare_downconvert(lockres, new_level);
3851         spin_unlock_irqrestore(&lockres->l_lock, flags);
3852         ret = ocfs2_downconvert_lock(osb, lockres, new_level, set_lvb,
3853                                      gen);
3854 
3855 leave:
3856         if (ret)
3857                 mlog_errno(ret);
3858         return ret;
3859 
3860 leave_requeue:
3861         spin_unlock_irqrestore(&lockres->l_lock, flags);
3862         ctl->requeue = 1;
3863 
3864         return 0;
3865 }
3866 
3867 static int ocfs2_data_convert_worker(struct ocfs2_lock_res *lockres,
3868                                      int blocking)
3869 {
3870         struct inode *inode;
3871         struct address_space *mapping;
3872         struct ocfs2_inode_info *oi;
3873 
3874         inode = ocfs2_lock_res_inode(lockres);
3875         mapping = inode->i_mapping;
3876 
3877         if (S_ISDIR(inode->i_mode)) {
3878                 oi = OCFS2_I(inode);
3879                 oi->ip_dir_lock_gen++;
3880                 mlog(0, "generation: %u\n", oi->ip_dir_lock_gen);
3881                 goto out;
3882         }
3883 
3884         if (!S_ISREG(inode->i_mode))
3885                 goto out;
3886 
3887         /*
3888          * We need this before the filemap_fdatawrite() so that it can
3889          * transfer the dirty bit from the PTE to the
3890          * page. Unfortunately this means that even for EX->PR
3891          * downconverts, we'll lose our mappings and have to build
3892          * them up again.
3893          */
3894         unmap_mapping_range(mapping, 0, 0, 0);
3895 
3896         if (filemap_fdatawrite(mapping)) {
3897                 mlog(ML_ERROR, "Could not sync inode %llu for downconvert!",
3898                      (unsigned long long)OCFS2_I(inode)->ip_blkno);
3899         }
3900         sync_mapping_buffers(mapping);
3901         if (blocking == DLM_LOCK_EX) {
3902                 truncate_inode_pages(mapping, 0);
3903         } else {
3904                 /* We only need to wait on the I/O if we're not also
3905                  * truncating pages because truncate_inode_pages waits
3906                  * for us above. We don't truncate pages if we're
3907                  * blocking anything < EXMODE because we want to keep
3908                  * them around in that case. */
3909                 filemap_fdatawait(mapping);
3910         }
3911 
3912         forget_all_cached_acls(inode);
3913 
3914 out:
3915         return UNBLOCK_CONTINUE;
3916 }
3917 
3918 static int ocfs2_ci_checkpointed(struct ocfs2_caching_info *ci,
3919                                  struct ocfs2_lock_res *lockres,
3920                                  int new_level)
3921 {
3922         int checkpointed = ocfs2_ci_fully_checkpointed(ci);
3923 
3924         BUG_ON(new_level != DLM_LOCK_NL && new_level != DLM_LOCK_PR);
3925         BUG_ON(lockres->l_level != DLM_LOCK_EX && !checkpointed);
3926 
3927         if (checkpointed)
3928                 return 1;
3929 
3930         ocfs2_start_checkpoint(OCFS2_SB(ocfs2_metadata_cache_get_super(ci)));
3931         return 0;
3932 }
3933 
3934 static int ocfs2_check_meta_downconvert(struct ocfs2_lock_res *lockres,
3935                                         int new_level)
3936 {
3937         struct inode *inode = ocfs2_lock_res_inode(lockres);
3938 
3939         return ocfs2_ci_checkpointed(INODE_CACHE(inode), lockres, new_level);
3940 }
3941 
3942 static void ocfs2_set_meta_lvb(struct ocfs2_lock_res *lockres)
3943 {
3944         struct inode *inode = ocfs2_lock_res_inode(lockres);
3945 
3946         __ocfs2_stuff_meta_lvb(inode);
3947 }
3948 
3949 /*
3950  * Does the final reference drop on our dentry lock. Right now this
3951  * happens in the downconvert thread, but we could choose to simplify the
3952  * dlmglue API and push these off to the ocfs2_wq in the future.
3953  */
3954 static void ocfs2_dentry_post_unlock(struct ocfs2_super *osb,
3955                                      struct ocfs2_lock_res *lockres)
3956 {
3957         struct ocfs2_dentry_lock *dl = ocfs2_lock_res_dl(lockres);
3958         ocfs2_dentry_lock_put(osb, dl);
3959 }
3960 
3961 /*
3962  * d_delete() matching dentries before the lock downconvert.
3963  *
3964  * At this point, any process waiting to destroy the
3965  * dentry_lock due to last ref count is stopped by the
3966  * OCFS2_LOCK_QUEUED flag.
3967  *
3968  * We have two potential problems
3969  *
3970  * 1) If we do the last reference drop on our dentry_lock (via dput)
3971  *    we'll wind up in ocfs2_release_dentry_lock(), waiting on
3972  *    the downconvert to finish. Instead we take an elevated
3973  *    reference and push the drop until after we've completed our
3974  *    unblock processing.
3975  *
3976  * 2) There might be another process with a final reference,
3977  *    waiting on us to finish processing. If this is the case, we
3978  *    detect it and exit out - there's no more dentries anyway.
3979  */
3980 static int ocfs2_dentry_convert_worker(struct ocfs2_lock_res *lockres,
3981                                        int blocking)
3982 {
3983         struct ocfs2_dentry_lock *dl = ocfs2_lock_res_dl(lockres);
3984         struct ocfs2_inode_info *oi = OCFS2_I(dl->dl_inode);
3985         struct dentry *dentry;
3986         unsigned long flags;
3987         int extra_ref = 0;
3988 
3989         /*
3990          * This node is blocking another node from getting a read
3991          * lock. This happens when we've renamed within a
3992          * directory. We've forced the other nodes to d_delete(), but
3993          * we never actually dropped our lock because it's still
3994          * valid. The downconvert code will retain a PR for this node,
3995          * so there's no further work to do.
3996          */
3997         if (blocking == DLM_LOCK_PR)
3998                 return UNBLOCK_CONTINUE;
3999 
4000         /*
4001          * Mark this inode as potentially orphaned. The code in
4002          * ocfs2_delete_inode() will figure out whether it actually
4003          * needs to be freed or not.
4004          */
4005         spin_lock(&oi->ip_lock);
4006         oi->ip_flags |= OCFS2_INODE_MAYBE_ORPHANED;
4007         spin_unlock(&oi->ip_lock);
4008 
4009         /*
4010          * Yuck. We need to make sure however that the check of
4011          * OCFS2_LOCK_FREEING and the extra reference are atomic with
4012          * respect to a reference decrement or the setting of that
4013          * flag.
4014          */
4015         spin_lock_irqsave(&lockres->l_lock, flags);
4016         spin_lock(&dentry_attach_lock);
4017         if (!(lockres->l_flags & OCFS2_LOCK_FREEING)
4018             && dl->dl_count) {
4019                 dl->dl_count++;
4020                 extra_ref = 1;
4021         }
4022         spin_unlock(&dentry_attach_lock);
4023         spin_unlock_irqrestore(&lockres->l_lock, flags);
4024 
4025         mlog(0, "extra_ref = %d\n", extra_ref);
4026 
4027         /*
4028          * We have a process waiting on us in ocfs2_dentry_iput(),
4029          * which means we can't have any more outstanding
4030          * aliases. There's no need to do any more work.
4031          */
4032         if (!extra_ref)
4033                 return UNBLOCK_CONTINUE;
4034 
4035         spin_lock(&dentry_attach_lock);
4036         while (1) {
4037                 dentry = ocfs2_find_local_alias(dl->dl_inode,
4038                                                 dl->dl_parent_blkno, 1);
4039                 if (!dentry)
4040                         break;
4041                 spin_unlock(&dentry_attach_lock);
4042 
4043                 if (S_ISDIR(dl->dl_inode->i_mode))
4044                         shrink_dcache_parent(dentry);
4045 
4046                 mlog(0, "d_delete(%pd);\n", dentry);
4047 
4048                 /*
4049                  * The following dcache calls may do an
4050                  * iput(). Normally we don't want that from the
4051                  * downconverting thread, but in this case it's ok
4052                  * because the requesting node already has an
4053                  * exclusive lock on the inode, so it can't be queued
4054                  * for a downconvert.
4055                  */
4056                 d_delete(dentry);
4057                 dput(dentry);
4058 
4059                 spin_lock(&dentry_attach_lock);
4060         }
4061         spin_unlock(&dentry_attach_lock);
4062 
4063         /*
4064          * If we are the last holder of this dentry lock, there is no
4065          * reason to downconvert so skip straight to the unlock.
4066          */
4067         if (dl->dl_count == 1)
4068                 return UNBLOCK_STOP_POST;
4069 
4070         return UNBLOCK_CONTINUE_POST;
4071 }
4072 
4073 static int ocfs2_check_refcount_downconvert(struct ocfs2_lock_res *lockres,
4074                                             int new_level)
4075 {
4076         struct ocfs2_refcount_tree *tree =
4077                                 ocfs2_lock_res_refcount_tree(lockres);
4078 
4079         return ocfs2_ci_checkpointed(&tree->rf_ci, lockres, new_level);
4080 }
4081 
4082 static int ocfs2_refcount_convert_worker(struct ocfs2_lock_res *lockres,
4083                                          int blocking)
4084 {
4085         struct ocfs2_refcount_tree *tree =
4086                                 ocfs2_lock_res_refcount_tree(lockres);
4087 
4088         ocfs2_metadata_cache_purge(&tree->rf_ci);
4089 
4090         return UNBLOCK_CONTINUE;
4091 }
4092 
4093 static void ocfs2_set_qinfo_lvb(struct ocfs2_lock_res *lockres)
4094 {
4095         struct ocfs2_qinfo_lvb *lvb;
4096         struct ocfs2_mem_dqinfo *oinfo = ocfs2_lock_res_qinfo(lockres);
4097         struct mem_dqinfo *info = sb_dqinfo(oinfo->dqi_gi.dqi_sb,
4098                                             oinfo->dqi_gi.dqi_type);
4099 
4100         lvb = ocfs2_dlm_lvb(&lockres->l_lksb);
4101         lvb->lvb_version = OCFS2_QINFO_LVB_VERSION;
4102         lvb->lvb_bgrace = cpu_to_be32(info->dqi_bgrace);
4103         lvb->lvb_igrace = cpu_to_be32(info->dqi_igrace);
4104         lvb->lvb_syncms = cpu_to_be32(oinfo->dqi_syncms);
4105         lvb->lvb_blocks = cpu_to_be32(oinfo->dqi_gi.dqi_blocks);
4106         lvb->lvb_free_blk = cpu_to_be32(oinfo->dqi_gi.dqi_free_blk);
4107         lvb->lvb_free_entry = cpu_to_be32(oinfo->dqi_gi.dqi_free_entry);
4108 }
4109 
4110 void ocfs2_qinfo_unlock(struct ocfs2_mem_dqinfo *oinfo, int ex)
4111 {
4112         struct ocfs2_lock_res *lockres = &oinfo->dqi_gqlock;
4113         struct ocfs2_super *osb = OCFS2_SB(oinfo->dqi_gi.dqi_sb);
4114         int level = ex ? DLM_LOCK_EX : DLM_LOCK_PR;
4115 
4116         if (!ocfs2_is_hard_readonly(osb) && !ocfs2_mount_local(osb))
4117                 ocfs2_cluster_unlock(osb, lockres, level);
4118 }
4119 
4120 static int ocfs2_refresh_qinfo(struct ocfs2_mem_dqinfo *oinfo)
4121 {
4122         struct mem_dqinfo *info = sb_dqinfo(oinfo->dqi_gi.dqi_sb,
4123                                             oinfo->dqi_gi.dqi_type);
4124         struct ocfs2_lock_res *lockres = &oinfo->dqi_gqlock;
4125         struct ocfs2_qinfo_lvb *lvb = ocfs2_dlm_lvb(&lockres->l_lksb);
4126         struct buffer_head *bh = NULL;
4127         struct ocfs2_global_disk_dqinfo *gdinfo;
4128         int status = 0;
4129 
4130         if (ocfs2_dlm_lvb_valid(&lockres->l_lksb) &&
4131             lvb->lvb_version == OCFS2_QINFO_LVB_VERSION) {
4132                 info->dqi_bgrace = be32_to_cpu(lvb->lvb_bgrace);
4133                 info->dqi_igrace = be32_to_cpu(lvb->lvb_igrace);
4134                 oinfo->dqi_syncms = be32_to_cpu(lvb->lvb_syncms);
4135                 oinfo->dqi_gi.dqi_blocks = be32_to_cpu(lvb->lvb_blocks);
4136                 oinfo->dqi_gi.dqi_free_blk = be32_to_cpu(lvb->lvb_free_blk);
4137                 oinfo->dqi_gi.dqi_free_entry =
4138                                         be32_to_cpu(lvb->lvb_free_entry);
4139         } else {
4140                 status = ocfs2_read_quota_phys_block(oinfo->dqi_gqinode,
4141                                                      oinfo->dqi_giblk, &bh);
4142                 if (status) {
4143                         mlog_errno(status);
4144                         goto bail;
4145                 }
4146                 gdinfo = (struct ocfs2_global_disk_dqinfo *)
4147                                         (bh->b_data + OCFS2_GLOBAL_INFO_OFF);
4148                 info->dqi_bgrace = le32_to_cpu(gdinfo->dqi_bgrace);
4149                 info->dqi_igrace = le32_to_cpu(gdinfo->dqi_igrace);
4150                 oinfo->dqi_syncms = le32_to_cpu(gdinfo->dqi_syncms);
4151                 oinfo->dqi_gi.dqi_blocks = le32_to_cpu(gdinfo->dqi_blocks);
4152                 oinfo->dqi_gi.dqi_free_blk = le32_to_cpu(gdinfo->dqi_free_blk);
4153                 oinfo->dqi_gi.dqi_free_entry =
4154                                         le32_to_cpu(gdinfo->dqi_free_entry);
4155                 brelse(bh);
4156                 ocfs2_track_lock_refresh(lockres);
4157         }
4158 
4159 bail:
4160         return status;
4161 }
4162 
4163 /* Lock quota info, this function expects at least shared lock on the quota file
4164  * so that we can safely refresh quota info from disk. */
4165 int ocfs2_qinfo_lock(struct ocfs2_mem_dqinfo *oinfo, int ex)
4166 {
4167         struct ocfs2_lock_res *lockres = &oinfo->dqi_gqlock;
4168         struct ocfs2_super *osb = OCFS2_SB(oinfo->dqi_gi.dqi_sb);
4169         int level = ex ? DLM_LOCK_EX : DLM_LOCK_PR;
4170         int status = 0;
4171 
4172         /* On RO devices, locking really isn't needed... */
4173         if (ocfs2_is_hard_readonly(osb)) {
4174                 if (ex)
4175                         status = -EROFS;
4176                 goto bail;
4177         }
4178         if (ocfs2_mount_local(osb))
4179                 goto bail;
4180 
4181         status = ocfs2_cluster_lock(osb, lockres, level, 0, 0);
4182         if (status < 0) {
4183                 mlog_errno(status);
4184                 goto bail;
4185         }
4186         if (!ocfs2_should_refresh_lock_res(lockres))
4187                 goto bail;
4188         /* OK, we have the lock but we need to refresh the quota info */
4189         status = ocfs2_refresh_qinfo(oinfo);
4190         if (status)
4191                 ocfs2_qinfo_unlock(oinfo, ex);
4192         ocfs2_complete_lock_res_refresh(lockres, status);
4193 bail:
4194         return status;
4195 }
4196 
4197 int ocfs2_refcount_lock(struct ocfs2_refcount_tree *ref_tree, int ex)
4198 {
4199         int status;
4200         int level = ex ? DLM_LOCK_EX : DLM_LOCK_PR;
4201         struct ocfs2_lock_res *lockres = &ref_tree->rf_lockres;
4202         struct ocfs2_super *osb = lockres->l_priv;
4203 
4204 
4205         if (ocfs2_is_hard_readonly(osb))
4206                 return -EROFS;
4207 
4208         if (ocfs2_mount_local(osb))
4209                 return 0;
4210 
4211         status = ocfs2_cluster_lock(osb, lockres, level, 0, 0);
4212         if (status < 0)
4213                 mlog_errno(status);
4214 
4215         return status;
4216 }
4217 
4218 void ocfs2_refcount_unlock(struct ocfs2_refcount_tree *ref_tree, int ex)
4219 {
4220         int level = ex ? DLM_LOCK_EX : DLM_LOCK_PR;
4221         struct ocfs2_lock_res *lockres = &ref_tree->rf_lockres;
4222         struct ocfs2_super *osb = lockres->l_priv;
4223 
4224         if (!ocfs2_mount_local(osb))
4225                 ocfs2_cluster_unlock(osb, lockres, level);
4226 }
4227 
4228 static void ocfs2_process_blocked_lock(struct ocfs2_super *osb,
4229                                        struct ocfs2_lock_res *lockres)
4230 {
4231         int status;
4232         struct ocfs2_unblock_ctl ctl = {0, 0,};
4233         unsigned long flags;
4234 
4235         /* Our reference to the lockres in this function can be
4236          * considered valid until we remove the OCFS2_LOCK_QUEUED
4237          * flag. */
4238 
4239         BUG_ON(!lockres);
4240         BUG_ON(!lockres->l_ops);
4241 
4242         mlog(ML_BASTS, "lockres %s blocked\n", lockres->l_name);
4243 
4244         /* Detect whether a lock has been marked as going away while
4245          * the downconvert thread was processing other things. A lock can
4246          * still be marked with OCFS2_LOCK_FREEING after this check,
4247          * but short circuiting here will still save us some
4248          * performance. */
4249         spin_lock_irqsave(&lockres->l_lock, flags);
4250         if (lockres->l_flags & OCFS2_LOCK_FREEING)
4251                 goto unqueue;
4252         spin_unlock_irqrestore(&lockres->l_lock, flags);
4253 
4254         status = ocfs2_unblock_lock(osb, lockres, &ctl);
4255         if (status < 0)
4256                 mlog_errno(status);
4257 
4258         spin_lock_irqsave(&lockres->l_lock, flags);
4259 unqueue:
4260         if (lockres->l_flags & OCFS2_LOCK_FREEING || !ctl.requeue) {
4261                 lockres_clear_flags(lockres, OCFS2_LOCK_QUEUED);
4262         } else
4263                 ocfs2_schedule_blocked_lock(osb, lockres);
4264 
4265         mlog(ML_BASTS, "lockres %s, requeue = %s.\n", lockres->l_name,
4266              ctl.requeue ? "yes" : "no");
4267         spin_unlock_irqrestore(&lockres->l_lock, flags);
4268 
4269         if (ctl.unblock_action != UNBLOCK_CONTINUE
4270             && lockres->l_ops->post_unlock)
4271                 lockres->l_ops->post_unlock(osb, lockres);
4272 }
4273 
4274 static void ocfs2_schedule_blocked_lock(struct ocfs2_super *osb,
4275                                         struct ocfs2_lock_res *lockres)
4276 {
4277         unsigned long flags;
4278 
4279         assert_spin_locked(&lockres->l_lock);
4280 
4281         if (lockres->l_flags & OCFS2_LOCK_FREEING) {
4282                 /* Do not schedule a lock for downconvert when it's on
4283                  * the way to destruction - any nodes wanting access
4284                  * to the resource will get it soon. */
4285                 mlog(ML_BASTS, "lockres %s won't be scheduled: flags 0x%lx\n",
4286                      lockres->l_name, lockres->l_flags);
4287                 return;
4288         }
4289 
4290         lockres_or_flags(lockres, OCFS2_LOCK_QUEUED);
4291 
4292         spin_lock_irqsave(&osb->dc_task_lock, flags);
4293         if (list_empty(&lockres->l_blocked_list)) {
4294                 list_add_tail(&lockres->l_blocked_list,
4295                               &osb->blocked_lock_list);
4296                 osb->blocked_lock_count++;
4297         }
4298         spin_unlock_irqrestore(&osb->dc_task_lock, flags);
4299 }
4300 
4301 static void ocfs2_downconvert_thread_do_work(struct ocfs2_super *osb)
4302 {
4303         unsigned long processed;
4304         unsigned long flags;
4305         struct ocfs2_lock_res *lockres;
4306 
4307         spin_lock_irqsave(&osb->dc_task_lock, flags);
4308         /* grab this early so we know to try again if a state change and
4309          * wake happens part-way through our work  */
4310         osb->dc_work_sequence = osb->dc_wake_sequence;
4311 
4312         processed = osb->blocked_lock_count;
4313         /*
4314          * blocked lock processing in this loop might call iput which can
4315          * remove items off osb->blocked_lock_list. Downconvert up to
4316          * 'processed' number of locks, but stop short if we had some
4317          * removed in ocfs2_mark_lockres_freeing when downconverting.
4318          */
4319         while (processed && !list_empty(&osb->blocked_lock_list)) {
4320                 lockres = list_entry(osb->blocked_lock_list.next,
4321                                      struct ocfs2_lock_res, l_blocked_list);
4322                 list_del_init(&lockres->l_blocked_list);
4323                 osb->blocked_lock_count--;
4324                 spin_unlock_irqrestore(&osb->dc_task_lock, flags);
4325 
4326                 BUG_ON(!processed);
4327                 processed--;
4328 
4329                 ocfs2_process_blocked_lock(osb, lockres);
4330 
4331                 spin_lock_irqsave(&osb->dc_task_lock, flags);
4332         }
4333         spin_unlock_irqrestore(&osb->dc_task_lock, flags);
4334 }
4335 
4336 static int ocfs2_downconvert_thread_lists_empty(struct ocfs2_super *osb)
4337 {
4338         int empty = 0;
4339         unsigned long flags;
4340 
4341         spin_lock_irqsave(&osb->dc_task_lock, flags);
4342         if (list_empty(&osb->blocked_lock_list))
4343                 empty = 1;
4344 
4345         spin_unlock_irqrestore(&osb->dc_task_lock, flags);
4346         return empty;
4347 }
4348 
4349 static int ocfs2_downconvert_thread_should_wake(struct ocfs2_super *osb)
4350 {
4351         int should_wake = 0;
4352         unsigned long flags;
4353 
4354         spin_lock_irqsave(&osb->dc_task_lock, flags);
4355         if (osb->dc_work_sequence != osb->dc_wake_sequence)
4356                 should_wake = 1;
4357         spin_unlock_irqrestore(&osb->dc_task_lock, flags);
4358 
4359         return should_wake;
4360 }
4361 
4362 static int ocfs2_downconvert_thread(void *arg)
4363 {
4364         int status = 0;
4365         struct ocfs2_super *osb = arg;
4366 
4367         /* only quit once we've been asked to stop and there is no more
4368          * work available */
4369         while (!(kthread_should_stop() &&
4370                 ocfs2_downconvert_thread_lists_empty(osb))) {
4371 
4372                 wait_event_interruptible(osb->dc_event,
4373                                          ocfs2_downconvert_thread_should_wake(osb) ||
4374                                          kthread_should_stop());
4375 
4376                 mlog(0, "downconvert_thread: awoken\n");
4377 
4378                 ocfs2_downconvert_thread_do_work(osb);
4379         }
4380 
4381         osb->dc_task = NULL;
4382         return status;
4383 }
4384 
4385 void ocfs2_wake_downconvert_thread(struct ocfs2_super *osb)
4386 {
4387         unsigned long flags;
4388 
4389         spin_lock_irqsave(&osb->dc_task_lock, flags);
4390         /* make sure the voting thread gets a swipe at whatever changes
4391          * the caller may have made to the voting state */
4392         osb->dc_wake_sequence++;
4393         spin_unlock_irqrestore(&osb->dc_task_lock, flags);
4394         wake_up(&osb->dc_event);
4395 }
4396 

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