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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 struct lock_class_key lockdep_keys[OCFS2_NUM_LOCK_TYPES];
100 
101 static int ocfs2_check_meta_downconvert(struct ocfs2_lock_res *lockres,
102                                         int new_level);
103 static void ocfs2_set_meta_lvb(struct ocfs2_lock_res *lockres);
104 
105 static int ocfs2_data_convert_worker(struct ocfs2_lock_res *lockres,
106                                      int blocking);
107 
108 static int ocfs2_dentry_convert_worker(struct ocfs2_lock_res *lockres,
109                                        int blocking);
110 
111 static void ocfs2_dentry_post_unlock(struct ocfs2_super *osb,
112                                      struct ocfs2_lock_res *lockres);
113 
114 static void ocfs2_set_qinfo_lvb(struct ocfs2_lock_res *lockres);
115 
116 static int ocfs2_check_refcount_downconvert(struct ocfs2_lock_res *lockres,
117                                             int new_level);
118 static int ocfs2_refcount_convert_worker(struct ocfs2_lock_res *lockres,
119                                          int blocking);
120 
121 #define mlog_meta_lvb(__level, __lockres) ocfs2_dump_meta_lvb_info(__level, __PRETTY_FUNCTION__, __LINE__, __lockres)
122 
123 /* This aids in debugging situations where a bad LVB might be involved. */
124 static void ocfs2_dump_meta_lvb_info(u64 level,
125                                      const char *function,
126                                      unsigned int line,
127                                      struct ocfs2_lock_res *lockres)
128 {
129         struct ocfs2_meta_lvb *lvb = ocfs2_dlm_lvb(&lockres->l_lksb);
130 
131         mlog(level, "LVB information for %s (called from %s:%u):\n",
132              lockres->l_name, function, line);
133         mlog(level, "version: %u, clusters: %u, generation: 0x%x\n",
134              lvb->lvb_version, be32_to_cpu(lvb->lvb_iclusters),
135              be32_to_cpu(lvb->lvb_igeneration));
136         mlog(level, "size: %llu, uid %u, gid %u, mode 0x%x\n",
137              (unsigned long long)be64_to_cpu(lvb->lvb_isize),
138              be32_to_cpu(lvb->lvb_iuid), be32_to_cpu(lvb->lvb_igid),
139              be16_to_cpu(lvb->lvb_imode));
140         mlog(level, "nlink %u, atime_packed 0x%llx, ctime_packed 0x%llx, "
141              "mtime_packed 0x%llx iattr 0x%x\n", be16_to_cpu(lvb->lvb_inlink),
142              (long long)be64_to_cpu(lvb->lvb_iatime_packed),
143              (long long)be64_to_cpu(lvb->lvb_ictime_packed),
144              (long long)be64_to_cpu(lvb->lvb_imtime_packed),
145              be32_to_cpu(lvb->lvb_iattr));
146 }
147 
148 
149 /*
150  * OCFS2 Lock Resource Operations
151  *
152  * These fine tune the behavior of the generic dlmglue locking infrastructure.
153  *
154  * The most basic of lock types can point ->l_priv to their respective
155  * struct ocfs2_super and allow the default actions to manage things.
156  *
157  * Right now, each lock type also needs to implement an init function,
158  * and trivial lock/unlock wrappers. ocfs2_simple_drop_lockres()
159  * should be called when the lock is no longer needed (i.e., object
160  * destruction time).
161  */
162 struct ocfs2_lock_res_ops {
163         /*
164          * Translate an ocfs2_lock_res * into an ocfs2_super *. Define
165          * this callback if ->l_priv is not an ocfs2_super pointer
166          */
167         struct ocfs2_super * (*get_osb)(struct ocfs2_lock_res *);
168 
169         /*
170          * Optionally called in the downconvert thread after a
171          * successful downconvert. The lockres will not be referenced
172          * after this callback is called, so it is safe to free
173          * memory, etc.
174          *
175          * The exact semantics of when this is called are controlled
176          * by ->downconvert_worker()
177          */
178         void (*post_unlock)(struct ocfs2_super *, struct ocfs2_lock_res *);
179 
180         /*
181          * Allow a lock type to add checks to determine whether it is
182          * safe to downconvert a lock. Return 0 to re-queue the
183          * downconvert at a later time, nonzero to continue.
184          *
185          * For most locks, the default checks that there are no
186          * incompatible holders are sufficient.
187          *
188          * Called with the lockres spinlock held.
189          */
190         int (*check_downconvert)(struct ocfs2_lock_res *, int);
191 
192         /*
193          * Allows a lock type to populate the lock value block. This
194          * is called on downconvert, and when we drop a lock.
195          *
196          * Locks that want to use this should set LOCK_TYPE_USES_LVB
197          * in the flags field.
198          *
199          * Called with the lockres spinlock held.
200          */
201         void (*set_lvb)(struct ocfs2_lock_res *);
202 
203         /*
204          * Called from the downconvert thread when it is determined
205          * that a lock will be downconverted. This is called without
206          * any locks held so the function can do work that might
207          * schedule (syncing out data, etc).
208          *
209          * This should return any one of the ocfs2_unblock_action
210          * values, depending on what it wants the thread to do.
211          */
212         int (*downconvert_worker)(struct ocfs2_lock_res *, int);
213 
214         /*
215          * LOCK_TYPE_* flags which describe the specific requirements
216          * of a lock type. Descriptions of each individual flag follow.
217          */
218         int flags;
219 };
220 
221 /*
222  * Some locks want to "refresh" potentially stale data when a
223  * meaningful (PRMODE or EXMODE) lock level is first obtained. If this
224  * flag is set, the OCFS2_LOCK_NEEDS_REFRESH flag will be set on the
225  * individual lockres l_flags member from the ast function. It is
226  * expected that the locking wrapper will clear the
227  * OCFS2_LOCK_NEEDS_REFRESH flag when done.
228  */
229 #define LOCK_TYPE_REQUIRES_REFRESH 0x1
230 
231 /*
232  * Indicate that a lock type makes use of the lock value block. The
233  * ->set_lvb lock type callback must be defined.
234  */
235 #define LOCK_TYPE_USES_LVB              0x2
236 
237 static struct ocfs2_lock_res_ops ocfs2_inode_rw_lops = {
238         .get_osb        = ocfs2_get_inode_osb,
239         .flags          = 0,
240 };
241 
242 static struct ocfs2_lock_res_ops ocfs2_inode_inode_lops = {
243         .get_osb        = ocfs2_get_inode_osb,
244         .check_downconvert = ocfs2_check_meta_downconvert,
245         .set_lvb        = ocfs2_set_meta_lvb,
246         .downconvert_worker = ocfs2_data_convert_worker,
247         .flags          = LOCK_TYPE_REQUIRES_REFRESH|LOCK_TYPE_USES_LVB,
248 };
249 
250 static struct ocfs2_lock_res_ops ocfs2_super_lops = {
251         .flags          = LOCK_TYPE_REQUIRES_REFRESH,
252 };
253 
254 static struct ocfs2_lock_res_ops ocfs2_rename_lops = {
255         .flags          = 0,
256 };
257 
258 static struct ocfs2_lock_res_ops ocfs2_nfs_sync_lops = {
259         .flags          = 0,
260 };
261 
262 static struct ocfs2_lock_res_ops ocfs2_trim_fs_lops = {
263         .flags          = LOCK_TYPE_REQUIRES_REFRESH|LOCK_TYPE_USES_LVB,
264 };
265 
266 static struct ocfs2_lock_res_ops ocfs2_orphan_scan_lops = {
267         .flags          = LOCK_TYPE_REQUIRES_REFRESH|LOCK_TYPE_USES_LVB,
268 };
269 
270 static struct ocfs2_lock_res_ops ocfs2_dentry_lops = {
271         .get_osb        = ocfs2_get_dentry_osb,
272         .post_unlock    = ocfs2_dentry_post_unlock,
273         .downconvert_worker = ocfs2_dentry_convert_worker,
274         .flags          = 0,
275 };
276 
277 static struct ocfs2_lock_res_ops ocfs2_inode_open_lops = {
278         .get_osb        = ocfs2_get_inode_osb,
279         .flags          = 0,
280 };
281 
282 static struct ocfs2_lock_res_ops ocfs2_flock_lops = {
283         .get_osb        = ocfs2_get_file_osb,
284         .flags          = 0,
285 };
286 
287 static struct ocfs2_lock_res_ops ocfs2_qinfo_lops = {
288         .set_lvb        = ocfs2_set_qinfo_lvb,
289         .get_osb        = ocfs2_get_qinfo_osb,
290         .flags          = LOCK_TYPE_REQUIRES_REFRESH | LOCK_TYPE_USES_LVB,
291 };
292 
293 static struct ocfs2_lock_res_ops ocfs2_refcount_block_lops = {
294         .check_downconvert = ocfs2_check_refcount_downconvert,
295         .downconvert_worker = ocfs2_refcount_convert_worker,
296         .flags          = 0,
297 };
298 
299 static inline int ocfs2_is_inode_lock(struct ocfs2_lock_res *lockres)
300 {
301         return lockres->l_type == OCFS2_LOCK_TYPE_META ||
302                 lockres->l_type == OCFS2_LOCK_TYPE_RW ||
303                 lockres->l_type == OCFS2_LOCK_TYPE_OPEN;
304 }
305 
306 static inline struct ocfs2_lock_res *ocfs2_lksb_to_lock_res(struct ocfs2_dlm_lksb *lksb)
307 {
308         return container_of(lksb, struct ocfs2_lock_res, l_lksb);
309 }
310 
311 static inline struct inode *ocfs2_lock_res_inode(struct ocfs2_lock_res *lockres)
312 {
313         BUG_ON(!ocfs2_is_inode_lock(lockres));
314 
315         return (struct inode *) lockres->l_priv;
316 }
317 
318 static inline struct ocfs2_dentry_lock *ocfs2_lock_res_dl(struct ocfs2_lock_res *lockres)
319 {
320         BUG_ON(lockres->l_type != OCFS2_LOCK_TYPE_DENTRY);
321 
322         return (struct ocfs2_dentry_lock *)lockres->l_priv;
323 }
324 
325 static inline struct ocfs2_mem_dqinfo *ocfs2_lock_res_qinfo(struct ocfs2_lock_res *lockres)
326 {
327         BUG_ON(lockres->l_type != OCFS2_LOCK_TYPE_QINFO);
328 
329         return (struct ocfs2_mem_dqinfo *)lockres->l_priv;
330 }
331 
332 static inline struct ocfs2_refcount_tree *
333 ocfs2_lock_res_refcount_tree(struct ocfs2_lock_res *res)
334 {
335         return container_of(res, struct ocfs2_refcount_tree, rf_lockres);
336 }
337 
338 static inline struct ocfs2_super *ocfs2_get_lockres_osb(struct ocfs2_lock_res *lockres)
339 {
340         if (lockres->l_ops->get_osb)
341                 return lockres->l_ops->get_osb(lockres);
342 
343         return (struct ocfs2_super *)lockres->l_priv;
344 }
345 
346 static int ocfs2_lock_create(struct ocfs2_super *osb,
347                              struct ocfs2_lock_res *lockres,
348                              int level,
349                              u32 dlm_flags);
350 static inline int ocfs2_may_continue_on_blocked_lock(struct ocfs2_lock_res *lockres,
351                                                      int wanted);
352 static void __ocfs2_cluster_unlock(struct ocfs2_super *osb,
353                                    struct ocfs2_lock_res *lockres,
354                                    int level, unsigned long caller_ip);
355 static inline void ocfs2_cluster_unlock(struct ocfs2_super *osb,
356                                         struct ocfs2_lock_res *lockres,
357                                         int level)
358 {
359         __ocfs2_cluster_unlock(osb, lockres, level, _RET_IP_);
360 }
361 
362 static inline void ocfs2_generic_handle_downconvert_action(struct ocfs2_lock_res *lockres);
363 static inline void ocfs2_generic_handle_convert_action(struct ocfs2_lock_res *lockres);
364 static inline void ocfs2_generic_handle_attach_action(struct ocfs2_lock_res *lockres);
365 static int ocfs2_generic_handle_bast(struct ocfs2_lock_res *lockres, int level);
366 static void ocfs2_schedule_blocked_lock(struct ocfs2_super *osb,
367                                         struct ocfs2_lock_res *lockres);
368 static inline void ocfs2_recover_from_dlm_error(struct ocfs2_lock_res *lockres,
369                                                 int convert);
370 #define ocfs2_log_dlm_error(_func, _err, _lockres) do {                                 \
371         if ((_lockres)->l_type != OCFS2_LOCK_TYPE_DENTRY)                               \
372                 mlog(ML_ERROR, "DLM error %d while calling %s on resource %s\n",        \
373                      _err, _func, _lockres->l_name);                                    \
374         else                                                                            \
375                 mlog(ML_ERROR, "DLM error %d while calling %s on resource %.*s%08x\n",  \
376                      _err, _func, OCFS2_DENTRY_LOCK_INO_START - 1, (_lockres)->l_name,  \
377                      (unsigned int)ocfs2_get_dentry_lock_ino(_lockres));                \
378 } while (0)
379 static int ocfs2_downconvert_thread(void *arg);
380 static void ocfs2_downconvert_on_unlock(struct ocfs2_super *osb,
381                                         struct ocfs2_lock_res *lockres);
382 static int ocfs2_inode_lock_update(struct inode *inode,
383                                   struct buffer_head **bh);
384 static void ocfs2_drop_osb_locks(struct ocfs2_super *osb);
385 static inline int ocfs2_highest_compat_lock_level(int level);
386 static unsigned int ocfs2_prepare_downconvert(struct ocfs2_lock_res *lockres,
387                                               int new_level);
388 static int ocfs2_downconvert_lock(struct ocfs2_super *osb,
389                                   struct ocfs2_lock_res *lockres,
390                                   int new_level,
391                                   int lvb,
392                                   unsigned int generation);
393 static int ocfs2_prepare_cancel_convert(struct ocfs2_super *osb,
394                                         struct ocfs2_lock_res *lockres);
395 static int ocfs2_cancel_convert(struct ocfs2_super *osb,
396                                 struct ocfs2_lock_res *lockres);
397 
398 
399 static void ocfs2_build_lock_name(enum ocfs2_lock_type type,
400                                   u64 blkno,
401                                   u32 generation,
402                                   char *name)
403 {
404         int len;
405 
406         BUG_ON(type >= OCFS2_NUM_LOCK_TYPES);
407 
408         len = snprintf(name, OCFS2_LOCK_ID_MAX_LEN, "%c%s%016llx%08x",
409                        ocfs2_lock_type_char(type), OCFS2_LOCK_ID_PAD,
410                        (long long)blkno, generation);
411 
412         BUG_ON(len != (OCFS2_LOCK_ID_MAX_LEN - 1));
413 
414         mlog(0, "built lock resource with name: %s\n", name);
415 }
416 
417 static DEFINE_SPINLOCK(ocfs2_dlm_tracking_lock);
418 
419 static void ocfs2_add_lockres_tracking(struct ocfs2_lock_res *res,
420                                        struct ocfs2_dlm_debug *dlm_debug)
421 {
422         mlog(0, "Add tracking for lockres %s\n", res->l_name);
423 
424         spin_lock(&ocfs2_dlm_tracking_lock);
425         list_add(&res->l_debug_list, &dlm_debug->d_lockres_tracking);
426         spin_unlock(&ocfs2_dlm_tracking_lock);
427 }
428 
429 static void ocfs2_remove_lockres_tracking(struct ocfs2_lock_res *res)
430 {
431         spin_lock(&ocfs2_dlm_tracking_lock);
432         if (!list_empty(&res->l_debug_list))
433                 list_del_init(&res->l_debug_list);
434         spin_unlock(&ocfs2_dlm_tracking_lock);
435 }
436 
437 #ifdef CONFIG_OCFS2_FS_STATS
438 static void ocfs2_init_lock_stats(struct ocfs2_lock_res *res)
439 {
440         res->l_lock_refresh = 0;
441         memset(&res->l_lock_prmode, 0, sizeof(struct ocfs2_lock_stats));
442         memset(&res->l_lock_exmode, 0, sizeof(struct ocfs2_lock_stats));
443 }
444 
445 static void ocfs2_update_lock_stats(struct ocfs2_lock_res *res, int level,
446                                     struct ocfs2_mask_waiter *mw, int ret)
447 {
448         u32 usec;
449         ktime_t kt;
450         struct ocfs2_lock_stats *stats;
451 
452         if (level == LKM_PRMODE)
453                 stats = &res->l_lock_prmode;
454         else if (level == LKM_EXMODE)
455                 stats = &res->l_lock_exmode;
456         else
457                 return;
458 
459         kt = ktime_sub(ktime_get(), mw->mw_lock_start);
460         usec = ktime_to_us(kt);
461 
462         stats->ls_gets++;
463         stats->ls_total += ktime_to_ns(kt);
464         /* overflow */
465         if (unlikely(stats->ls_gets == 0)) {
466                 stats->ls_gets++;
467                 stats->ls_total = ktime_to_ns(kt);
468         }
469 
470         if (stats->ls_max < usec)
471                 stats->ls_max = usec;
472 
473         if (ret)
474                 stats->ls_fail++;
475 }
476 
477 static inline void ocfs2_track_lock_refresh(struct ocfs2_lock_res *lockres)
478 {
479         lockres->l_lock_refresh++;
480 }
481 
482 static inline void ocfs2_init_start_time(struct ocfs2_mask_waiter *mw)
483 {
484         mw->mw_lock_start = ktime_get();
485 }
486 #else
487 static inline void ocfs2_init_lock_stats(struct ocfs2_lock_res *res)
488 {
489 }
490 static inline void ocfs2_update_lock_stats(struct ocfs2_lock_res *res,
491                            int level, struct ocfs2_mask_waiter *mw, int ret)
492 {
493 }
494 static inline void ocfs2_track_lock_refresh(struct ocfs2_lock_res *lockres)
495 {
496 }
497 static inline void ocfs2_init_start_time(struct ocfs2_mask_waiter *mw)
498 {
499 }
500 #endif
501 
502 static void ocfs2_lock_res_init_common(struct ocfs2_super *osb,
503                                        struct ocfs2_lock_res *res,
504                                        enum ocfs2_lock_type type,
505                                        struct ocfs2_lock_res_ops *ops,
506                                        void *priv)
507 {
508         res->l_type          = type;
509         res->l_ops           = ops;
510         res->l_priv          = priv;
511 
512         res->l_level         = DLM_LOCK_IV;
513         res->l_requested     = DLM_LOCK_IV;
514         res->l_blocking      = DLM_LOCK_IV;
515         res->l_action        = OCFS2_AST_INVALID;
516         res->l_unlock_action = OCFS2_UNLOCK_INVALID;
517 
518         res->l_flags         = OCFS2_LOCK_INITIALIZED;
519 
520         ocfs2_add_lockres_tracking(res, osb->osb_dlm_debug);
521 
522         ocfs2_init_lock_stats(res);
523 #ifdef CONFIG_DEBUG_LOCK_ALLOC
524         if (type != OCFS2_LOCK_TYPE_OPEN)
525                 lockdep_init_map(&res->l_lockdep_map, ocfs2_lock_type_strings[type],
526                                  &lockdep_keys[type], 0);
527         else
528                 res->l_lockdep_map.key = NULL;
529 #endif
530 }
531 
532 void ocfs2_lock_res_init_once(struct ocfs2_lock_res *res)
533 {
534         /* This also clears out the lock status block */
535         memset(res, 0, sizeof(struct ocfs2_lock_res));
536         spin_lock_init(&res->l_lock);
537         init_waitqueue_head(&res->l_event);
538         INIT_LIST_HEAD(&res->l_blocked_list);
539         INIT_LIST_HEAD(&res->l_mask_waiters);
540         INIT_LIST_HEAD(&res->l_holders);
541 }
542 
543 void ocfs2_inode_lock_res_init(struct ocfs2_lock_res *res,
544                                enum ocfs2_lock_type type,
545                                unsigned int generation,
546                                struct inode *inode)
547 {
548         struct ocfs2_lock_res_ops *ops;
549 
550         switch(type) {
551                 case OCFS2_LOCK_TYPE_RW:
552                         ops = &ocfs2_inode_rw_lops;
553                         break;
554                 case OCFS2_LOCK_TYPE_META:
555                         ops = &ocfs2_inode_inode_lops;
556                         break;
557                 case OCFS2_LOCK_TYPE_OPEN:
558                         ops = &ocfs2_inode_open_lops;
559                         break;
560                 default:
561                         mlog_bug_on_msg(1, "type: %d\n", type);
562                         ops = NULL; /* thanks, gcc */
563                         break;
564         };
565 
566         ocfs2_build_lock_name(type, OCFS2_I(inode)->ip_blkno,
567                               generation, res->l_name);
568         ocfs2_lock_res_init_common(OCFS2_SB(inode->i_sb), res, type, ops, inode);
569 }
570 
571 static struct ocfs2_super *ocfs2_get_inode_osb(struct ocfs2_lock_res *lockres)
572 {
573         struct inode *inode = ocfs2_lock_res_inode(lockres);
574 
575         return OCFS2_SB(inode->i_sb);
576 }
577 
578 static struct ocfs2_super *ocfs2_get_qinfo_osb(struct ocfs2_lock_res *lockres)
579 {
580         struct ocfs2_mem_dqinfo *info = lockres->l_priv;
581 
582         return OCFS2_SB(info->dqi_gi.dqi_sb);
583 }
584 
585 static struct ocfs2_super *ocfs2_get_file_osb(struct ocfs2_lock_res *lockres)
586 {
587         struct ocfs2_file_private *fp = lockres->l_priv;
588 
589         return OCFS2_SB(fp->fp_file->f_mapping->host->i_sb);
590 }
591 
592 static __u64 ocfs2_get_dentry_lock_ino(struct ocfs2_lock_res *lockres)
593 {
594         __be64 inode_blkno_be;
595 
596         memcpy(&inode_blkno_be, &lockres->l_name[OCFS2_DENTRY_LOCK_INO_START],
597                sizeof(__be64));
598 
599         return be64_to_cpu(inode_blkno_be);
600 }
601 
602 static struct ocfs2_super *ocfs2_get_dentry_osb(struct ocfs2_lock_res *lockres)
603 {
604         struct ocfs2_dentry_lock *dl = lockres->l_priv;
605 
606         return OCFS2_SB(dl->dl_inode->i_sb);
607 }
608 
609 void ocfs2_dentry_lock_res_init(struct ocfs2_dentry_lock *dl,
610                                 u64 parent, struct inode *inode)
611 {
612         int len;
613         u64 inode_blkno = OCFS2_I(inode)->ip_blkno;
614         __be64 inode_blkno_be = cpu_to_be64(inode_blkno);
615         struct ocfs2_lock_res *lockres = &dl->dl_lockres;
616 
617         ocfs2_lock_res_init_once(lockres);
618 
619         /*
620          * Unfortunately, the standard lock naming scheme won't work
621          * here because we have two 16 byte values to use. Instead,
622          * we'll stuff the inode number as a binary value. We still
623          * want error prints to show something without garbling the
624          * display, so drop a null byte in there before the inode
625          * number. A future version of OCFS2 will likely use all
626          * binary lock names. The stringified names have been a
627          * tremendous aid in debugging, but now that the debugfs
628          * interface exists, we can mangle things there if need be.
629          *
630          * NOTE: We also drop the standard "pad" value (the total lock
631          * name size stays the same though - the last part is all
632          * zeros due to the memset in ocfs2_lock_res_init_once()
633          */
634         len = snprintf(lockres->l_name, OCFS2_DENTRY_LOCK_INO_START,
635                        "%c%016llx",
636                        ocfs2_lock_type_char(OCFS2_LOCK_TYPE_DENTRY),
637                        (long long)parent);
638 
639         BUG_ON(len != (OCFS2_DENTRY_LOCK_INO_START - 1));
640 
641         memcpy(&lockres->l_name[OCFS2_DENTRY_LOCK_INO_START], &inode_blkno_be,
642                sizeof(__be64));
643 
644         ocfs2_lock_res_init_common(OCFS2_SB(inode->i_sb), lockres,
645                                    OCFS2_LOCK_TYPE_DENTRY, &ocfs2_dentry_lops,
646                                    dl);
647 }
648 
649 static void ocfs2_super_lock_res_init(struct ocfs2_lock_res *res,
650                                       struct ocfs2_super *osb)
651 {
652         /* Superblock lockres doesn't come from a slab so we call init
653          * once on it manually.  */
654         ocfs2_lock_res_init_once(res);
655         ocfs2_build_lock_name(OCFS2_LOCK_TYPE_SUPER, OCFS2_SUPER_BLOCK_BLKNO,
656                               0, res->l_name);
657         ocfs2_lock_res_init_common(osb, res, OCFS2_LOCK_TYPE_SUPER,
658                                    &ocfs2_super_lops, osb);
659 }
660 
661 static void ocfs2_rename_lock_res_init(struct ocfs2_lock_res *res,
662                                        struct ocfs2_super *osb)
663 {
664         /* Rename lockres doesn't come from a slab so we call init
665          * once on it manually.  */
666         ocfs2_lock_res_init_once(res);
667         ocfs2_build_lock_name(OCFS2_LOCK_TYPE_RENAME, 0, 0, res->l_name);
668         ocfs2_lock_res_init_common(osb, res, OCFS2_LOCK_TYPE_RENAME,
669                                    &ocfs2_rename_lops, osb);
670 }
671 
672 static void ocfs2_nfs_sync_lock_res_init(struct ocfs2_lock_res *res,
673                                          struct ocfs2_super *osb)
674 {
675         /* nfs_sync lockres doesn't come from a slab so we call init
676          * once on it manually.  */
677         ocfs2_lock_res_init_once(res);
678         ocfs2_build_lock_name(OCFS2_LOCK_TYPE_NFS_SYNC, 0, 0, res->l_name);
679         ocfs2_lock_res_init_common(osb, res, OCFS2_LOCK_TYPE_NFS_SYNC,
680                                    &ocfs2_nfs_sync_lops, osb);
681 }
682 
683 void ocfs2_trim_fs_lock_res_init(struct ocfs2_super *osb)
684 {
685         struct ocfs2_lock_res *lockres = &osb->osb_trim_fs_lockres;
686 
687         ocfs2_lock_res_init_once(lockres);
688         ocfs2_build_lock_name(OCFS2_LOCK_TYPE_TRIM_FS, 0, 0, lockres->l_name);
689         ocfs2_lock_res_init_common(osb, lockres, OCFS2_LOCK_TYPE_TRIM_FS,
690                                    &ocfs2_trim_fs_lops, osb);
691 }
692 
693 void ocfs2_trim_fs_lock_res_uninit(struct ocfs2_super *osb)
694 {
695         struct ocfs2_lock_res *lockres = &osb->osb_trim_fs_lockres;
696 
697         ocfs2_simple_drop_lockres(osb, lockres);
698         ocfs2_lock_res_free(lockres);
699 }
700 
701 static void ocfs2_orphan_scan_lock_res_init(struct ocfs2_lock_res *res,
702                                             struct ocfs2_super *osb)
703 {
704         ocfs2_lock_res_init_once(res);
705         ocfs2_build_lock_name(OCFS2_LOCK_TYPE_ORPHAN_SCAN, 0, 0, res->l_name);
706         ocfs2_lock_res_init_common(osb, res, OCFS2_LOCK_TYPE_ORPHAN_SCAN,
707                                    &ocfs2_orphan_scan_lops, osb);
708 }
709 
710 void ocfs2_file_lock_res_init(struct ocfs2_lock_res *lockres,
711                               struct ocfs2_file_private *fp)
712 {
713         struct inode *inode = fp->fp_file->f_mapping->host;
714         struct ocfs2_inode_info *oi = OCFS2_I(inode);
715 
716         ocfs2_lock_res_init_once(lockres);
717         ocfs2_build_lock_name(OCFS2_LOCK_TYPE_FLOCK, oi->ip_blkno,
718                               inode->i_generation, lockres->l_name);
719         ocfs2_lock_res_init_common(OCFS2_SB(inode->i_sb), lockres,
720                                    OCFS2_LOCK_TYPE_FLOCK, &ocfs2_flock_lops,
721                                    fp);
722         lockres->l_flags |= OCFS2_LOCK_NOCACHE;
723 }
724 
725 void ocfs2_qinfo_lock_res_init(struct ocfs2_lock_res *lockres,
726                                struct ocfs2_mem_dqinfo *info)
727 {
728         ocfs2_lock_res_init_once(lockres);
729         ocfs2_build_lock_name(OCFS2_LOCK_TYPE_QINFO, info->dqi_gi.dqi_type,
730                               0, lockres->l_name);
731         ocfs2_lock_res_init_common(OCFS2_SB(info->dqi_gi.dqi_sb), lockres,
732                                    OCFS2_LOCK_TYPE_QINFO, &ocfs2_qinfo_lops,
733                                    info);
734 }
735 
736 void ocfs2_refcount_lock_res_init(struct ocfs2_lock_res *lockres,
737                                   struct ocfs2_super *osb, u64 ref_blkno,
738                                   unsigned int generation)
739 {
740         ocfs2_lock_res_init_once(lockres);
741         ocfs2_build_lock_name(OCFS2_LOCK_TYPE_REFCOUNT, ref_blkno,
742                               generation, lockres->l_name);
743         ocfs2_lock_res_init_common(osb, lockres, OCFS2_LOCK_TYPE_REFCOUNT,
744                                    &ocfs2_refcount_block_lops, osb);
745 }
746 
747 void ocfs2_lock_res_free(struct ocfs2_lock_res *res)
748 {
749         if (!(res->l_flags & OCFS2_LOCK_INITIALIZED))
750                 return;
751 
752         ocfs2_remove_lockres_tracking(res);
753 
754         mlog_bug_on_msg(!list_empty(&res->l_blocked_list),
755                         "Lockres %s is on the blocked list\n",
756                         res->l_name);
757         mlog_bug_on_msg(!list_empty(&res->l_mask_waiters),
758                         "Lockres %s has mask waiters pending\n",
759                         res->l_name);
760         mlog_bug_on_msg(spin_is_locked(&res->l_lock),
761                         "Lockres %s is locked\n",
762                         res->l_name);
763         mlog_bug_on_msg(res->l_ro_holders,
764                         "Lockres %s has %u ro holders\n",
765                         res->l_name, res->l_ro_holders);
766         mlog_bug_on_msg(res->l_ex_holders,
767                         "Lockres %s has %u ex holders\n",
768                         res->l_name, res->l_ex_holders);
769 
770         /* Need to clear out the lock status block for the dlm */
771         memset(&res->l_lksb, 0, sizeof(res->l_lksb));
772 
773         res->l_flags = 0UL;
774 }
775 
776 /*
777  * Keep a list of processes who have interest in a lockres.
778  * Note: this is now only uesed for check recursive cluster locking.
779  */
780 static inline void ocfs2_add_holder(struct ocfs2_lock_res *lockres,
781                                    struct ocfs2_lock_holder *oh)
782 {
783         INIT_LIST_HEAD(&oh->oh_list);
784         oh->oh_owner_pid = get_pid(task_pid(current));
785 
786         spin_lock(&lockres->l_lock);
787         list_add_tail(&oh->oh_list, &lockres->l_holders);
788         spin_unlock(&lockres->l_lock);
789 }
790 
791 static inline void ocfs2_remove_holder(struct ocfs2_lock_res *lockres,
792                                        struct ocfs2_lock_holder *oh)
793 {
794         spin_lock(&lockres->l_lock);
795         list_del(&oh->oh_list);
796         spin_unlock(&lockres->l_lock);
797 
798         put_pid(oh->oh_owner_pid);
799 }
800 
801 static inline int ocfs2_is_locked_by_me(struct ocfs2_lock_res *lockres)
802 {
803         struct ocfs2_lock_holder *oh;
804         struct pid *pid;
805 
806         /* look in the list of holders for one with the current task as owner */
807         spin_lock(&lockres->l_lock);
808         pid = task_pid(current);
809         list_for_each_entry(oh, &lockres->l_holders, oh_list) {
810                 if (oh->oh_owner_pid == pid) {
811                         spin_unlock(&lockres->l_lock);
812                         return 1;
813                 }
814         }
815         spin_unlock(&lockres->l_lock);
816 
817         return 0;
818 }
819 
820 static inline void ocfs2_inc_holders(struct ocfs2_lock_res *lockres,
821                                      int level)
822 {
823         BUG_ON(!lockres);
824 
825         switch(level) {
826         case DLM_LOCK_EX:
827                 lockres->l_ex_holders++;
828                 break;
829         case DLM_LOCK_PR:
830                 lockres->l_ro_holders++;
831                 break;
832         default:
833                 BUG();
834         }
835 }
836 
837 static inline void ocfs2_dec_holders(struct ocfs2_lock_res *lockres,
838                                      int level)
839 {
840         BUG_ON(!lockres);
841 
842         switch(level) {
843         case DLM_LOCK_EX:
844                 BUG_ON(!lockres->l_ex_holders);
845                 lockres->l_ex_holders--;
846                 break;
847         case DLM_LOCK_PR:
848                 BUG_ON(!lockres->l_ro_holders);
849                 lockres->l_ro_holders--;
850                 break;
851         default:
852                 BUG();
853         }
854 }
855 
856 /* WARNING: This function lives in a world where the only three lock
857  * levels are EX, PR, and NL. It *will* have to be adjusted when more
858  * lock types are added. */
859 static inline int ocfs2_highest_compat_lock_level(int level)
860 {
861         int new_level = DLM_LOCK_EX;
862 
863         if (level == DLM_LOCK_EX)
864                 new_level = DLM_LOCK_NL;
865         else if (level == DLM_LOCK_PR)
866                 new_level = DLM_LOCK_PR;
867         return new_level;
868 }
869 
870 static void lockres_set_flags(struct ocfs2_lock_res *lockres,
871                               unsigned long newflags)
872 {
873         struct ocfs2_mask_waiter *mw, *tmp;
874 
875         assert_spin_locked(&lockres->l_lock);
876 
877         lockres->l_flags = newflags;
878 
879         list_for_each_entry_safe(mw, tmp, &lockres->l_mask_waiters, mw_item) {
880                 if ((lockres->l_flags & mw->mw_mask) != mw->mw_goal)
881                         continue;
882 
883                 list_del_init(&mw->mw_item);
884                 mw->mw_status = 0;
885                 complete(&mw->mw_complete);
886         }
887 }
888 static void lockres_or_flags(struct ocfs2_lock_res *lockres, unsigned long or)
889 {
890         lockres_set_flags(lockres, lockres->l_flags | or);
891 }
892 static void lockres_clear_flags(struct ocfs2_lock_res *lockres,
893                                 unsigned long clear)
894 {
895         lockres_set_flags(lockres, lockres->l_flags & ~clear);
896 }
897 
898 static inline void ocfs2_generic_handle_downconvert_action(struct ocfs2_lock_res *lockres)
899 {
900         BUG_ON(!(lockres->l_flags & OCFS2_LOCK_BUSY));
901         BUG_ON(!(lockres->l_flags & OCFS2_LOCK_ATTACHED));
902         BUG_ON(!(lockres->l_flags & OCFS2_LOCK_BLOCKED));
903         BUG_ON(lockres->l_blocking <= DLM_LOCK_NL);
904 
905         lockres->l_level = lockres->l_requested;
906         if (lockres->l_level <=
907             ocfs2_highest_compat_lock_level(lockres->l_blocking)) {
908                 lockres->l_blocking = DLM_LOCK_NL;
909                 lockres_clear_flags(lockres, OCFS2_LOCK_BLOCKED);
910         }
911         lockres_clear_flags(lockres, OCFS2_LOCK_BUSY);
912 }
913 
914 static inline void ocfs2_generic_handle_convert_action(struct ocfs2_lock_res *lockres)
915 {
916         BUG_ON(!(lockres->l_flags & OCFS2_LOCK_BUSY));
917         BUG_ON(!(lockres->l_flags & OCFS2_LOCK_ATTACHED));
918 
919         /* Convert from RO to EX doesn't really need anything as our
920          * information is already up to data. Convert from NL to
921          * *anything* however should mark ourselves as needing an
922          * update */
923         if (lockres->l_level == DLM_LOCK_NL &&
924             lockres->l_ops->flags & LOCK_TYPE_REQUIRES_REFRESH)
925                 lockres_or_flags(lockres, OCFS2_LOCK_NEEDS_REFRESH);
926 
927         lockres->l_level = lockres->l_requested;
928 
929         /*
930          * We set the OCFS2_LOCK_UPCONVERT_FINISHING flag before clearing
931          * the OCFS2_LOCK_BUSY flag to prevent the dc thread from
932          * downconverting the lock before the upconvert has fully completed.
933          * Do not prevent the dc thread from downconverting if NONBLOCK lock
934          * had already returned.
935          */
936         if (!(lockres->l_flags & OCFS2_LOCK_NONBLOCK_FINISHED))
937                 lockres_or_flags(lockres, OCFS2_LOCK_UPCONVERT_FINISHING);
938         else
939                 lockres_clear_flags(lockres, OCFS2_LOCK_NONBLOCK_FINISHED);
940 
941         lockres_clear_flags(lockres, OCFS2_LOCK_BUSY);
942 }
943 
944 static inline void ocfs2_generic_handle_attach_action(struct ocfs2_lock_res *lockres)
945 {
946         BUG_ON((!(lockres->l_flags & OCFS2_LOCK_BUSY)));
947         BUG_ON(lockres->l_flags & OCFS2_LOCK_ATTACHED);
948 
949         if (lockres->l_requested > DLM_LOCK_NL &&
950             !(lockres->l_flags & OCFS2_LOCK_LOCAL) &&
951             lockres->l_ops->flags & LOCK_TYPE_REQUIRES_REFRESH)
952                 lockres_or_flags(lockres, OCFS2_LOCK_NEEDS_REFRESH);
953 
954         lockres->l_level = lockres->l_requested;
955         lockres_or_flags(lockres, OCFS2_LOCK_ATTACHED);
956         lockres_clear_flags(lockres, OCFS2_LOCK_BUSY);
957 }
958 
959 static int ocfs2_generic_handle_bast(struct ocfs2_lock_res *lockres,
960                                      int level)
961 {
962         int needs_downconvert = 0;
963 
964         assert_spin_locked(&lockres->l_lock);
965 
966         if (level > lockres->l_blocking) {
967                 /* only schedule a downconvert if we haven't already scheduled
968                  * one that goes low enough to satisfy the level we're
969                  * blocking.  this also catches the case where we get
970                  * duplicate BASTs */
971                 if (ocfs2_highest_compat_lock_level(level) <
972                     ocfs2_highest_compat_lock_level(lockres->l_blocking))
973                         needs_downconvert = 1;
974 
975                 lockres->l_blocking = level;
976         }
977 
978         mlog(ML_BASTS, "lockres %s, block %d, level %d, l_block %d, dwn %d\n",
979              lockres->l_name, level, lockres->l_level, lockres->l_blocking,
980              needs_downconvert);
981 
982         if (needs_downconvert)
983                 lockres_or_flags(lockres, OCFS2_LOCK_BLOCKED);
984         mlog(0, "needs_downconvert = %d\n", needs_downconvert);
985         return needs_downconvert;
986 }
987 
988 /*
989  * OCFS2_LOCK_PENDING and l_pending_gen.
990  *
991  * Why does OCFS2_LOCK_PENDING exist?  To close a race between setting
992  * OCFS2_LOCK_BUSY and calling ocfs2_dlm_lock().  See ocfs2_unblock_lock()
993  * for more details on the race.
994  *
995  * OCFS2_LOCK_PENDING closes the race quite nicely.  However, it introduces
996  * a race on itself.  In o2dlm, we can get the ast before ocfs2_dlm_lock()
997  * returns.  The ast clears OCFS2_LOCK_BUSY, and must therefore clear
998  * OCFS2_LOCK_PENDING at the same time.  When ocfs2_dlm_lock() returns,
999  * the caller is going to try to clear PENDING again.  If nothing else is
1000  * happening, __lockres_clear_pending() sees PENDING is unset and does
1001  * nothing.
1002  *
1003  * But what if another path (eg downconvert thread) has just started a
1004  * new locking action?  The other path has re-set PENDING.  Our path
1005  * cannot clear PENDING, because that will re-open the original race
1006  * window.
1007  *
1008  * [Example]
1009  *
1010  * ocfs2_meta_lock()
1011  *  ocfs2_cluster_lock()
1012  *   set BUSY
1013  *   set PENDING
1014  *   drop l_lock
1015  *   ocfs2_dlm_lock()
1016  *    ocfs2_locking_ast()               ocfs2_downconvert_thread()
1017  *     clear PENDING                     ocfs2_unblock_lock()
1018  *                                        take_l_lock
1019  *                                        !BUSY
1020  *                                        ocfs2_prepare_downconvert()
1021  *                                         set BUSY
1022  *                                         set PENDING
1023  *                                        drop l_lock
1024  *   take l_lock
1025  *   clear PENDING
1026  *   drop l_lock
1027  *                      <window>
1028  *                                        ocfs2_dlm_lock()
1029  *
1030  * So as you can see, we now have a window where l_lock is not held,
1031  * PENDING is not set, and ocfs2_dlm_lock() has not been called.
1032  *
1033  * The core problem is that ocfs2_cluster_lock() has cleared the PENDING
1034  * set by ocfs2_prepare_downconvert().  That wasn't nice.
1035  *
1036  * To solve this we introduce l_pending_gen.  A call to
1037  * lockres_clear_pending() will only do so when it is passed a generation
1038  * number that matches the lockres.  lockres_set_pending() will return the
1039  * current generation number.  When ocfs2_cluster_lock() goes to clear
1040  * PENDING, it passes the generation it got from set_pending().  In our
1041  * example above, the generation numbers will *not* match.  Thus,
1042  * ocfs2_cluster_lock() will not clear the PENDING set by
1043  * ocfs2_prepare_downconvert().
1044  */
1045 
1046 /* Unlocked version for ocfs2_locking_ast() */
1047 static void __lockres_clear_pending(struct ocfs2_lock_res *lockres,
1048                                     unsigned int generation,
1049                                     struct ocfs2_super *osb)
1050 {
1051         assert_spin_locked(&lockres->l_lock);
1052 
1053         /*
1054          * The ast and locking functions can race us here.  The winner
1055          * will clear pending, the loser will not.
1056          */
1057         if (!(lockres->l_flags & OCFS2_LOCK_PENDING) ||
1058             (lockres->l_pending_gen != generation))
1059                 return;
1060 
1061         lockres_clear_flags(lockres, OCFS2_LOCK_PENDING);
1062         lockres->l_pending_gen++;
1063 
1064         /*
1065          * The downconvert thread may have skipped us because we
1066          * were PENDING.  Wake it up.
1067          */
1068         if (lockres->l_flags & OCFS2_LOCK_BLOCKED)
1069                 ocfs2_wake_downconvert_thread(osb);
1070 }
1071 
1072 /* Locked version for callers of ocfs2_dlm_lock() */
1073 static void lockres_clear_pending(struct ocfs2_lock_res *lockres,
1074                                   unsigned int generation,
1075                                   struct ocfs2_super *osb)
1076 {
1077         unsigned long flags;
1078 
1079         spin_lock_irqsave(&lockres->l_lock, flags);
1080         __lockres_clear_pending(lockres, generation, osb);
1081         spin_unlock_irqrestore(&lockres->l_lock, flags);
1082 }
1083 
1084 static unsigned int lockres_set_pending(struct ocfs2_lock_res *lockres)
1085 {
1086         assert_spin_locked(&lockres->l_lock);
1087         BUG_ON(!(lockres->l_flags & OCFS2_LOCK_BUSY));
1088 
1089         lockres_or_flags(lockres, OCFS2_LOCK_PENDING);
1090 
1091         return lockres->l_pending_gen;
1092 }
1093 
1094 static void ocfs2_blocking_ast(struct ocfs2_dlm_lksb *lksb, int level)
1095 {
1096         struct ocfs2_lock_res *lockres = ocfs2_lksb_to_lock_res(lksb);
1097         struct ocfs2_super *osb = ocfs2_get_lockres_osb(lockres);
1098         int needs_downconvert;
1099         unsigned long flags;
1100 
1101         BUG_ON(level <= DLM_LOCK_NL);
1102 
1103         mlog(ML_BASTS, "BAST fired for lockres %s, blocking %d, level %d, "
1104              "type %s\n", lockres->l_name, level, lockres->l_level,
1105              ocfs2_lock_type_string(lockres->l_type));
1106 
1107         /*
1108          * We can skip the bast for locks which don't enable caching -
1109          * they'll be dropped at the earliest possible time anyway.
1110          */
1111         if (lockres->l_flags & OCFS2_LOCK_NOCACHE)
1112                 return;
1113 
1114         spin_lock_irqsave(&lockres->l_lock, flags);
1115         needs_downconvert = ocfs2_generic_handle_bast(lockres, level);
1116         if (needs_downconvert)
1117                 ocfs2_schedule_blocked_lock(osb, lockres);
1118         spin_unlock_irqrestore(&lockres->l_lock, flags);
1119 
1120         wake_up(&lockres->l_event);
1121 
1122         ocfs2_wake_downconvert_thread(osb);
1123 }
1124 
1125 static void ocfs2_locking_ast(struct ocfs2_dlm_lksb *lksb)
1126 {
1127         struct ocfs2_lock_res *lockres = ocfs2_lksb_to_lock_res(lksb);
1128         struct ocfs2_super *osb = ocfs2_get_lockres_osb(lockres);
1129         unsigned long flags;
1130         int status;
1131 
1132         spin_lock_irqsave(&lockres->l_lock, flags);
1133 
1134         status = ocfs2_dlm_lock_status(&lockres->l_lksb);
1135 
1136         if (status == -EAGAIN) {
1137                 lockres_clear_flags(lockres, OCFS2_LOCK_BUSY);
1138                 goto out;
1139         }
1140 
1141         if (status) {
1142                 mlog(ML_ERROR, "lockres %s: lksb status value of %d!\n",
1143                      lockres->l_name, status);
1144                 spin_unlock_irqrestore(&lockres->l_lock, flags);
1145                 return;
1146         }
1147 
1148         mlog(ML_BASTS, "AST fired for lockres %s, action %d, unlock %d, "
1149              "level %d => %d\n", lockres->l_name, lockres->l_action,
1150              lockres->l_unlock_action, lockres->l_level, lockres->l_requested);
1151 
1152         switch(lockres->l_action) {
1153         case OCFS2_AST_ATTACH:
1154                 ocfs2_generic_handle_attach_action(lockres);
1155                 lockres_clear_flags(lockres, OCFS2_LOCK_LOCAL);
1156                 break;
1157         case OCFS2_AST_CONVERT:
1158                 ocfs2_generic_handle_convert_action(lockres);
1159                 break;
1160         case OCFS2_AST_DOWNCONVERT:
1161                 ocfs2_generic_handle_downconvert_action(lockres);
1162                 break;
1163         default:
1164                 mlog(ML_ERROR, "lockres %s: AST fired with invalid action: %u, "
1165                      "flags 0x%lx, unlock: %u\n",
1166                      lockres->l_name, lockres->l_action, lockres->l_flags,
1167                      lockres->l_unlock_action);
1168                 BUG();
1169         }
1170 out:
1171         /* set it to something invalid so if we get called again we
1172          * can catch it. */
1173         lockres->l_action = OCFS2_AST_INVALID;
1174 
1175         /* Did we try to cancel this lock?  Clear that state */
1176         if (lockres->l_unlock_action == OCFS2_UNLOCK_CANCEL_CONVERT)
1177                 lockres->l_unlock_action = OCFS2_UNLOCK_INVALID;
1178 
1179         /*
1180          * We may have beaten the locking functions here.  We certainly
1181          * know that dlm_lock() has been called :-)
1182          * Because we can't have two lock calls in flight at once, we
1183          * can use lockres->l_pending_gen.
1184          */
1185         __lockres_clear_pending(lockres, lockres->l_pending_gen,  osb);
1186 
1187         wake_up(&lockres->l_event);
1188         spin_unlock_irqrestore(&lockres->l_lock, flags);
1189 }
1190 
1191 static void ocfs2_unlock_ast(struct ocfs2_dlm_lksb *lksb, int error)
1192 {
1193         struct ocfs2_lock_res *lockres = ocfs2_lksb_to_lock_res(lksb);
1194         unsigned long flags;
1195 
1196         mlog(ML_BASTS, "UNLOCK AST fired for lockres %s, action = %d\n",
1197              lockres->l_name, lockres->l_unlock_action);
1198 
1199         spin_lock_irqsave(&lockres->l_lock, flags);
1200         if (error) {
1201                 mlog(ML_ERROR, "Dlm passes error %d for lock %s, "
1202                      "unlock_action %d\n", error, lockres->l_name,
1203                      lockres->l_unlock_action);
1204                 spin_unlock_irqrestore(&lockres->l_lock, flags);
1205                 return;
1206         }
1207 
1208         switch(lockres->l_unlock_action) {
1209         case OCFS2_UNLOCK_CANCEL_CONVERT:
1210                 mlog(0, "Cancel convert success for %s\n", lockres->l_name);
1211                 lockres->l_action = OCFS2_AST_INVALID;
1212                 /* Downconvert thread may have requeued this lock, we
1213                  * need to wake it. */
1214                 if (lockres->l_flags & OCFS2_LOCK_BLOCKED)
1215                         ocfs2_wake_downconvert_thread(ocfs2_get_lockres_osb(lockres));
1216                 break;
1217         case OCFS2_UNLOCK_DROP_LOCK:
1218                 lockres->l_level = DLM_LOCK_IV;
1219                 break;
1220         default:
1221                 BUG();
1222         }
1223 
1224         lockres_clear_flags(lockres, OCFS2_LOCK_BUSY);
1225         lockres->l_unlock_action = OCFS2_UNLOCK_INVALID;
1226         wake_up(&lockres->l_event);
1227         spin_unlock_irqrestore(&lockres->l_lock, flags);
1228 }
1229 
1230 /*
1231  * This is the filesystem locking protocol.  It provides the lock handling
1232  * hooks for the underlying DLM.  It has a maximum version number.
1233  * The version number allows interoperability with systems running at
1234  * the same major number and an equal or smaller minor number.
1235  *
1236  * Whenever the filesystem does new things with locks (adds or removes a
1237  * lock, orders them differently, does different things underneath a lock),
1238  * the version must be changed.  The protocol is negotiated when joining
1239  * the dlm domain.  A node may join the domain if its major version is
1240  * identical to all other nodes and its minor version is greater than
1241  * or equal to all other nodes.  When its minor version is greater than
1242  * the other nodes, it will run at the minor version specified by the
1243  * other nodes.
1244  *
1245  * If a locking change is made that will not be compatible with older
1246  * versions, the major number must be increased and the minor version set
1247  * to zero.  If a change merely adds a behavior that can be disabled when
1248  * speaking to older versions, the minor version must be increased.  If a
1249  * change adds a fully backwards compatible change (eg, LVB changes that
1250  * are just ignored by older versions), the version does not need to be
1251  * updated.
1252  */
1253 static struct ocfs2_locking_protocol lproto = {
1254         .lp_max_version = {
1255                 .pv_major = OCFS2_LOCKING_PROTOCOL_MAJOR,
1256                 .pv_minor = OCFS2_LOCKING_PROTOCOL_MINOR,
1257         },
1258         .lp_lock_ast            = ocfs2_locking_ast,
1259         .lp_blocking_ast        = ocfs2_blocking_ast,
1260         .lp_unlock_ast          = ocfs2_unlock_ast,
1261 };
1262 
1263 void ocfs2_set_locking_protocol(void)
1264 {
1265         ocfs2_stack_glue_set_max_proto_version(&lproto.lp_max_version);
1266 }
1267 
1268 static inline void ocfs2_recover_from_dlm_error(struct ocfs2_lock_res *lockres,
1269                                                 int convert)
1270 {
1271         unsigned long flags;
1272 
1273         spin_lock_irqsave(&lockres->l_lock, flags);
1274         lockres_clear_flags(lockres, OCFS2_LOCK_BUSY);
1275         lockres_clear_flags(lockres, OCFS2_LOCK_UPCONVERT_FINISHING);
1276         if (convert)
1277                 lockres->l_action = OCFS2_AST_INVALID;
1278         else
1279                 lockres->l_unlock_action = OCFS2_UNLOCK_INVALID;
1280         spin_unlock_irqrestore(&lockres->l_lock, flags);
1281 
1282         wake_up(&lockres->l_event);
1283 }
1284 
1285 /* Note: If we detect another process working on the lock (i.e.,
1286  * OCFS2_LOCK_BUSY), we'll bail out returning 0. It's up to the caller
1287  * to do the right thing in that case.
1288  */
1289 static int ocfs2_lock_create(struct ocfs2_super *osb,
1290                              struct ocfs2_lock_res *lockres,
1291                              int level,
1292                              u32 dlm_flags)
1293 {
1294         int ret = 0;
1295         unsigned long flags;
1296         unsigned int gen;
1297 
1298         mlog(0, "lock %s, level = %d, flags = %u\n", lockres->l_name, level,
1299              dlm_flags);
1300 
1301         spin_lock_irqsave(&lockres->l_lock, flags);
1302         if ((lockres->l_flags & OCFS2_LOCK_ATTACHED) ||
1303             (lockres->l_flags & OCFS2_LOCK_BUSY)) {
1304                 spin_unlock_irqrestore(&lockres->l_lock, flags);
1305                 goto bail;
1306         }
1307 
1308         lockres->l_action = OCFS2_AST_ATTACH;
1309         lockres->l_requested = level;
1310         lockres_or_flags(lockres, OCFS2_LOCK_BUSY);
1311         gen = lockres_set_pending(lockres);
1312         spin_unlock_irqrestore(&lockres->l_lock, flags);
1313 
1314         ret = ocfs2_dlm_lock(osb->cconn,
1315                              level,
1316                              &lockres->l_lksb,
1317                              dlm_flags,
1318                              lockres->l_name,
1319                              OCFS2_LOCK_ID_MAX_LEN - 1);
1320         lockres_clear_pending(lockres, gen, osb);
1321         if (ret) {
1322                 ocfs2_log_dlm_error("ocfs2_dlm_lock", ret, lockres);
1323                 ocfs2_recover_from_dlm_error(lockres, 1);
1324         }
1325 
1326         mlog(0, "lock %s, return from ocfs2_dlm_lock\n", lockres->l_name);
1327 
1328 bail:
1329         return ret;
1330 }
1331 
1332 static inline int ocfs2_check_wait_flag(struct ocfs2_lock_res *lockres,
1333                                         int flag)
1334 {
1335         unsigned long flags;
1336         int ret;
1337 
1338         spin_lock_irqsave(&lockres->l_lock, flags);
1339         ret = lockres->l_flags & flag;
1340         spin_unlock_irqrestore(&lockres->l_lock, flags);
1341 
1342         return ret;
1343 }
1344 
1345 static inline void ocfs2_wait_on_busy_lock(struct ocfs2_lock_res *lockres)
1346 
1347 {
1348         wait_event(lockres->l_event,
1349                    !ocfs2_check_wait_flag(lockres, OCFS2_LOCK_BUSY));
1350 }
1351 
1352 static inline void ocfs2_wait_on_refreshing_lock(struct ocfs2_lock_res *lockres)
1353 
1354 {
1355         wait_event(lockres->l_event,
1356                    !ocfs2_check_wait_flag(lockres, OCFS2_LOCK_REFRESHING));
1357 }
1358 
1359 /* predict what lock level we'll be dropping down to on behalf
1360  * of another node, and return true if the currently wanted
1361  * level will be compatible with it. */
1362 static inline int ocfs2_may_continue_on_blocked_lock(struct ocfs2_lock_res *lockres,
1363                                                      int wanted)
1364 {
1365         BUG_ON(!(lockres->l_flags & OCFS2_LOCK_BLOCKED));
1366 
1367         return wanted <= ocfs2_highest_compat_lock_level(lockres->l_blocking);
1368 }
1369 
1370 static void ocfs2_init_mask_waiter(struct ocfs2_mask_waiter *mw)
1371 {
1372         INIT_LIST_HEAD(&mw->mw_item);
1373         init_completion(&mw->mw_complete);
1374         ocfs2_init_start_time(mw);
1375 }
1376 
1377 static int ocfs2_wait_for_mask(struct ocfs2_mask_waiter *mw)
1378 {
1379         wait_for_completion(&mw->mw_complete);
1380         /* Re-arm the completion in case we want to wait on it again */
1381         reinit_completion(&mw->mw_complete);
1382         return mw->mw_status;
1383 }
1384 
1385 static void lockres_add_mask_waiter(struct ocfs2_lock_res *lockres,
1386                                     struct ocfs2_mask_waiter *mw,
1387                                     unsigned long mask,
1388                                     unsigned long goal)
1389 {
1390         BUG_ON(!list_empty(&mw->mw_item));
1391 
1392         assert_spin_locked(&lockres->l_lock);
1393 
1394         list_add_tail(&mw->mw_item, &lockres->l_mask_waiters);
1395         mw->mw_mask = mask;
1396         mw->mw_goal = goal;
1397 }
1398 
1399 /* returns 0 if the mw that was removed was already satisfied, -EBUSY
1400  * if the mask still hadn't reached its goal */
1401 static int __lockres_remove_mask_waiter(struct ocfs2_lock_res *lockres,
1402                                       struct ocfs2_mask_waiter *mw)
1403 {
1404         int ret = 0;
1405 
1406         assert_spin_locked(&lockres->l_lock);
1407         if (!list_empty(&mw->mw_item)) {
1408                 if ((lockres->l_flags & mw->mw_mask) != mw->mw_goal)
1409                         ret = -EBUSY;
1410 
1411                 list_del_init(&mw->mw_item);
1412                 init_completion(&mw->mw_complete);
1413         }
1414 
1415         return ret;
1416 }
1417 
1418 static int lockres_remove_mask_waiter(struct ocfs2_lock_res *lockres,
1419                                       struct ocfs2_mask_waiter *mw)
1420 {
1421         unsigned long flags;
1422         int ret = 0;
1423 
1424         spin_lock_irqsave(&lockres->l_lock, flags);
1425         ret = __lockres_remove_mask_waiter(lockres, mw);
1426         spin_unlock_irqrestore(&lockres->l_lock, flags);
1427 
1428         return ret;
1429 
1430 }
1431 
1432 static int ocfs2_wait_for_mask_interruptible(struct ocfs2_mask_waiter *mw,
1433                                              struct ocfs2_lock_res *lockres)
1434 {
1435         int ret;
1436 
1437         ret = wait_for_completion_interruptible(&mw->mw_complete);
1438         if (ret)
1439                 lockres_remove_mask_waiter(lockres, mw);
1440         else
1441                 ret = mw->mw_status;
1442         /* Re-arm the completion in case we want to wait on it again */
1443         reinit_completion(&mw->mw_complete);
1444         return ret;
1445 }
1446 
1447 static int __ocfs2_cluster_lock(struct ocfs2_super *osb,
1448                                 struct ocfs2_lock_res *lockres,
1449                                 int level,
1450                                 u32 lkm_flags,
1451                                 int arg_flags,
1452                                 int l_subclass,
1453                                 unsigned long caller_ip)
1454 {
1455         struct ocfs2_mask_waiter mw;
1456         int wait, catch_signals = !(osb->s_mount_opt & OCFS2_MOUNT_NOINTR);
1457         int ret = 0; /* gcc doesn't realize wait = 1 guarantees ret is set */
1458         unsigned long flags;
1459         unsigned int gen;
1460         int noqueue_attempted = 0;
1461         int dlm_locked = 0;
1462         int kick_dc = 0;
1463 
1464         if (!(lockres->l_flags & OCFS2_LOCK_INITIALIZED)) {
1465                 mlog_errno(-EINVAL);
1466                 return -EINVAL;
1467         }
1468 
1469         ocfs2_init_mask_waiter(&mw);
1470 
1471         if (lockres->l_ops->flags & LOCK_TYPE_USES_LVB)
1472                 lkm_flags |= DLM_LKF_VALBLK;
1473 
1474 again:
1475         wait = 0;
1476 
1477         spin_lock_irqsave(&lockres->l_lock, flags);
1478 
1479         if (catch_signals && signal_pending(current)) {
1480                 ret = -ERESTARTSYS;
1481                 goto unlock;
1482         }
1483 
1484         mlog_bug_on_msg(lockres->l_flags & OCFS2_LOCK_FREEING,
1485                         "Cluster lock called on freeing lockres %s! flags "
1486                         "0x%lx\n", lockres->l_name, lockres->l_flags);
1487 
1488         /* We only compare against the currently granted level
1489          * here. If the lock is blocked waiting on a downconvert,
1490          * we'll get caught below. */
1491         if (lockres->l_flags & OCFS2_LOCK_BUSY &&
1492             level > lockres->l_level) {
1493                 /* is someone sitting in dlm_lock? If so, wait on
1494                  * them. */
1495                 lockres_add_mask_waiter(lockres, &mw, OCFS2_LOCK_BUSY, 0);
1496                 wait = 1;
1497                 goto unlock;
1498         }
1499 
1500         if (lockres->l_flags & OCFS2_LOCK_UPCONVERT_FINISHING) {
1501                 /*
1502                  * We've upconverted. If the lock now has a level we can
1503                  * work with, we take it. If, however, the lock is not at the
1504                  * required level, we go thru the full cycle. One way this could
1505                  * happen is if a process requesting an upconvert to PR is
1506                  * closely followed by another requesting upconvert to an EX.
1507                  * If the process requesting EX lands here, we want it to
1508                  * continue attempting to upconvert and let the process
1509                  * requesting PR take the lock.
1510                  * If multiple processes request upconvert to PR, the first one
1511                  * here will take the lock. The others will have to go thru the
1512                  * OCFS2_LOCK_BLOCKED check to ensure that there is no pending
1513                  * downconvert request.
1514                  */
1515                 if (level <= lockres->l_level)
1516                         goto update_holders;
1517         }
1518 
1519         if (lockres->l_flags & OCFS2_LOCK_BLOCKED &&
1520             !ocfs2_may_continue_on_blocked_lock(lockres, level)) {
1521                 /* is the lock is currently blocked on behalf of
1522                  * another node */
1523                 lockres_add_mask_waiter(lockres, &mw, OCFS2_LOCK_BLOCKED, 0);
1524                 wait = 1;
1525                 goto unlock;
1526         }
1527 
1528         if (level > lockres->l_level) {
1529                 if (noqueue_attempted > 0) {
1530                         ret = -EAGAIN;
1531                         goto unlock;
1532                 }
1533                 if (lkm_flags & DLM_LKF_NOQUEUE)
1534                         noqueue_attempted = 1;
1535 
1536                 if (lockres->l_action != OCFS2_AST_INVALID)
1537                         mlog(ML_ERROR, "lockres %s has action %u pending\n",
1538                              lockres->l_name, lockres->l_action);
1539 
1540                 if (!(lockres->l_flags & OCFS2_LOCK_ATTACHED)) {
1541                         lockres->l_action = OCFS2_AST_ATTACH;
1542                         lkm_flags &= ~DLM_LKF_CONVERT;
1543                 } else {
1544                         lockres->l_action = OCFS2_AST_CONVERT;
1545                         lkm_flags |= DLM_LKF_CONVERT;
1546                 }
1547 
1548                 lockres->l_requested = level;
1549                 lockres_or_flags(lockres, OCFS2_LOCK_BUSY);
1550                 gen = lockres_set_pending(lockres);
1551                 spin_unlock_irqrestore(&lockres->l_lock, flags);
1552 
1553                 BUG_ON(level == DLM_LOCK_IV);
1554                 BUG_ON(level == DLM_LOCK_NL);
1555 
1556                 mlog(ML_BASTS, "lockres %s, convert from %d to %d\n",
1557                      lockres->l_name, lockres->l_level, level);
1558 
1559                 /* call dlm_lock to upgrade lock now */
1560                 ret = ocfs2_dlm_lock(osb->cconn,
1561                                      level,
1562                                      &lockres->l_lksb,
1563                                      lkm_flags,
1564                                      lockres->l_name,
1565                                      OCFS2_LOCK_ID_MAX_LEN - 1);
1566                 lockres_clear_pending(lockres, gen, osb);
1567                 if (ret) {
1568                         if (!(lkm_flags & DLM_LKF_NOQUEUE) ||
1569                             (ret != -EAGAIN)) {
1570                                 ocfs2_log_dlm_error("ocfs2_dlm_lock",
1571                                                     ret, lockres);
1572                         }
1573                         ocfs2_recover_from_dlm_error(lockres, 1);
1574                         goto out;
1575                 }
1576                 dlm_locked = 1;
1577 
1578                 mlog(0, "lock %s, successful return from ocfs2_dlm_lock\n",
1579                      lockres->l_name);
1580 
1581                 /* At this point we've gone inside the dlm and need to
1582                  * complete our work regardless. */
1583                 catch_signals = 0;
1584 
1585                 /* wait for busy to clear and carry on */
1586                 goto again;
1587         }
1588 
1589 update_holders:
1590         /* Ok, if we get here then we're good to go. */
1591         ocfs2_inc_holders(lockres, level);
1592 
1593         ret = 0;
1594 unlock:
1595         lockres_clear_flags(lockres, OCFS2_LOCK_UPCONVERT_FINISHING);
1596 
1597         /* ocfs2_unblock_lock reques on seeing OCFS2_LOCK_UPCONVERT_FINISHING */
1598         kick_dc = (lockres->l_flags & OCFS2_LOCK_BLOCKED);
1599 
1600         spin_unlock_irqrestore(&lockres->l_lock, flags);
1601         if (kick_dc)
1602                 ocfs2_wake_downconvert_thread(osb);
1603 out:
1604         /*
1605          * This is helping work around a lock inversion between the page lock
1606          * and dlm locks.  One path holds the page lock while calling aops
1607          * which block acquiring dlm locks.  The voting thread holds dlm
1608          * locks while acquiring page locks while down converting data locks.
1609          * This block is helping an aop path notice the inversion and back
1610          * off to unlock its page lock before trying the dlm lock again.
1611          */
1612         if (wait && arg_flags & OCFS2_LOCK_NONBLOCK &&
1613             mw.mw_mask & (OCFS2_LOCK_BUSY|OCFS2_LOCK_BLOCKED)) {
1614                 wait = 0;
1615                 spin_lock_irqsave(&lockres->l_lock, flags);
1616                 if (__lockres_remove_mask_waiter(lockres, &mw)) {
1617                         if (dlm_locked)
1618                                 lockres_or_flags(lockres,
1619                                         OCFS2_LOCK_NONBLOCK_FINISHED);
1620                         spin_unlock_irqrestore(&lockres->l_lock, flags);
1621                         ret = -EAGAIN;
1622                 } else {
1623                         spin_unlock_irqrestore(&lockres->l_lock, flags);
1624                         goto again;
1625                 }
1626         }
1627         if (wait) {
1628                 ret = ocfs2_wait_for_mask(&mw);
1629                 if (ret == 0)
1630                         goto again;
1631                 mlog_errno(ret);
1632         }
1633         ocfs2_update_lock_stats(lockres, level, &mw, ret);
1634 
1635 #ifdef CONFIG_DEBUG_LOCK_ALLOC
1636         if (!ret && lockres->l_lockdep_map.key != NULL) {
1637                 if (level == DLM_LOCK_PR)
1638                         rwsem_acquire_read(&lockres->l_lockdep_map, l_subclass,
1639                                 !!(arg_flags & OCFS2_META_LOCK_NOQUEUE),
1640                                 caller_ip);
1641                 else
1642                         rwsem_acquire(&lockres->l_lockdep_map, l_subclass,
1643                                 !!(arg_flags & OCFS2_META_LOCK_NOQUEUE),
1644                                 caller_ip);
1645         }
1646 #endif
1647         return ret;
1648 }
1649 
1650 static inline int ocfs2_cluster_lock(struct ocfs2_super *osb,
1651                                      struct ocfs2_lock_res *lockres,
1652                                      int level,
1653                                      u32 lkm_flags,
1654                                      int arg_flags)
1655 {
1656         return __ocfs2_cluster_lock(osb, lockres, level, lkm_flags, arg_flags,
1657                                     0, _RET_IP_);
1658 }
1659 
1660 
1661 static void __ocfs2_cluster_unlock(struct ocfs2_super *osb,
1662                                    struct ocfs2_lock_res *lockres,
1663                                    int level,
1664                                    unsigned long caller_ip)
1665 {
1666         unsigned long flags;
1667 
1668         spin_lock_irqsave(&lockres->l_lock, flags);
1669         ocfs2_dec_holders(lockres, level);
1670         ocfs2_downconvert_on_unlock(osb, lockres);
1671         spin_unlock_irqrestore(&lockres->l_lock, flags);
1672 #ifdef CONFIG_DEBUG_LOCK_ALLOC
1673         if (lockres->l_lockdep_map.key != NULL)
1674                 rwsem_release(&lockres->l_lockdep_map, 1, caller_ip);
1675 #endif
1676 }
1677 
1678 static int ocfs2_create_new_lock(struct ocfs2_super *osb,
1679                                  struct ocfs2_lock_res *lockres,
1680                                  int ex,
1681                                  int local)
1682 {
1683         int level =  ex ? DLM_LOCK_EX : DLM_LOCK_PR;
1684         unsigned long flags;
1685         u32 lkm_flags = local ? DLM_LKF_LOCAL : 0;
1686 
1687         spin_lock_irqsave(&lockres->l_lock, flags);
1688         BUG_ON(lockres->l_flags & OCFS2_LOCK_ATTACHED);
1689         lockres_or_flags(lockres, OCFS2_LOCK_LOCAL);
1690         spin_unlock_irqrestore(&lockres->l_lock, flags);
1691 
1692         return ocfs2_lock_create(osb, lockres, level, lkm_flags);
1693 }
1694 
1695 /* Grants us an EX lock on the data and metadata resources, skipping
1696  * the normal cluster directory lookup. Use this ONLY on newly created
1697  * inodes which other nodes can't possibly see, and which haven't been
1698  * hashed in the inode hash yet. This can give us a good performance
1699  * increase as it'll skip the network broadcast normally associated
1700  * with creating a new lock resource. */
1701 int ocfs2_create_new_inode_locks(struct inode *inode)
1702 {
1703         int ret;
1704         struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
1705 
1706         BUG_ON(!ocfs2_inode_is_new(inode));
1707 
1708         mlog(0, "Inode %llu\n", (unsigned long long)OCFS2_I(inode)->ip_blkno);
1709 
1710         /* NOTE: That we don't increment any of the holder counts, nor
1711          * do we add anything to a journal handle. Since this is
1712          * supposed to be a new inode which the cluster doesn't know
1713          * about yet, there is no need to.  As far as the LVB handling
1714          * is concerned, this is basically like acquiring an EX lock
1715          * on a resource which has an invalid one -- we'll set it
1716          * valid when we release the EX. */
1717 
1718         ret = ocfs2_create_new_lock(osb, &OCFS2_I(inode)->ip_rw_lockres, 1, 1);
1719         if (ret) {
1720                 mlog_errno(ret);
1721                 goto bail;
1722         }
1723 
1724         /*
1725          * We don't want to use DLM_LKF_LOCAL on a meta data lock as they
1726          * don't use a generation in their lock names.
1727          */
1728         ret = ocfs2_create_new_lock(osb, &OCFS2_I(inode)->ip_inode_lockres, 1, 0);
1729         if (ret) {
1730                 mlog_errno(ret);
1731                 goto bail;
1732         }
1733 
1734         ret = ocfs2_create_new_lock(osb, &OCFS2_I(inode)->ip_open_lockres, 0, 0);
1735         if (ret)
1736                 mlog_errno(ret);
1737 
1738 bail:
1739         return ret;
1740 }
1741 
1742 int ocfs2_rw_lock(struct inode *inode, int write)
1743 {
1744         int status, level;
1745         struct ocfs2_lock_res *lockres;
1746         struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
1747 
1748         mlog(0, "inode %llu take %s RW lock\n",
1749              (unsigned long long)OCFS2_I(inode)->ip_blkno,
1750              write ? "EXMODE" : "PRMODE");
1751 
1752         if (ocfs2_mount_local(osb))
1753                 return 0;
1754 
1755         lockres = &OCFS2_I(inode)->ip_rw_lockres;
1756 
1757         level = write ? DLM_LOCK_EX : DLM_LOCK_PR;
1758 
1759         status = ocfs2_cluster_lock(osb, lockres, level, 0, 0);
1760         if (status < 0)
1761                 mlog_errno(status);
1762 
1763         return status;
1764 }
1765 
1766 int ocfs2_try_rw_lock(struct inode *inode, int write)
1767 {
1768         int status, level;
1769         struct ocfs2_lock_res *lockres;
1770         struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
1771 
1772         mlog(0, "inode %llu try to take %s RW lock\n",
1773              (unsigned long long)OCFS2_I(inode)->ip_blkno,
1774              write ? "EXMODE" : "PRMODE");
1775 
1776         if (ocfs2_mount_local(osb))
1777                 return 0;
1778 
1779         lockres = &OCFS2_I(inode)->ip_rw_lockres;
1780 
1781         level = write ? DLM_LOCK_EX : DLM_LOCK_PR;
1782 
1783         status = ocfs2_cluster_lock(osb, lockres, level, DLM_LKF_NOQUEUE, 0);
1784         return status;
1785 }
1786 
1787 void ocfs2_rw_unlock(struct inode *inode, int write)
1788 {
1789         int level = write ? DLM_LOCK_EX : DLM_LOCK_PR;
1790         struct ocfs2_lock_res *lockres = &OCFS2_I(inode)->ip_rw_lockres;
1791         struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
1792 
1793         mlog(0, "inode %llu drop %s RW lock\n",
1794              (unsigned long long)OCFS2_I(inode)->ip_blkno,
1795              write ? "EXMODE" : "PRMODE");
1796 
1797         if (!ocfs2_mount_local(osb))
1798                 ocfs2_cluster_unlock(osb, lockres, level);
1799 }
1800 
1801 /*
1802  * ocfs2_open_lock always get PR mode lock.
1803  */
1804 int ocfs2_open_lock(struct inode *inode)
1805 {
1806         int status = 0;
1807         struct ocfs2_lock_res *lockres;
1808         struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
1809 
1810         mlog(0, "inode %llu take PRMODE open lock\n",
1811              (unsigned long long)OCFS2_I(inode)->ip_blkno);
1812 
1813         if (ocfs2_is_hard_readonly(osb) || ocfs2_mount_local(osb))
1814                 goto out;
1815 
1816         lockres = &OCFS2_I(inode)->ip_open_lockres;
1817 
1818         status = ocfs2_cluster_lock(osb, lockres, DLM_LOCK_PR, 0, 0);
1819         if (status < 0)
1820                 mlog_errno(status);
1821 
1822 out:
1823         return status;
1824 }
1825 
1826 int ocfs2_try_open_lock(struct inode *inode, int write)
1827 {
1828         int status = 0, level;
1829         struct ocfs2_lock_res *lockres;
1830         struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
1831 
1832         mlog(0, "inode %llu try to take %s open lock\n",
1833              (unsigned long long)OCFS2_I(inode)->ip_blkno,
1834              write ? "EXMODE" : "PRMODE");
1835 
1836         if (ocfs2_is_hard_readonly(osb)) {
1837                 if (write)
1838                         status = -EROFS;
1839                 goto out;
1840         }
1841 
1842         if (ocfs2_mount_local(osb))
1843                 goto out;
1844 
1845         lockres = &OCFS2_I(inode)->ip_open_lockres;
1846 
1847         level = write ? DLM_LOCK_EX : DLM_LOCK_PR;
1848 
1849         /*
1850          * The file system may already holding a PRMODE/EXMODE open lock.
1851          * Since we pass DLM_LKF_NOQUEUE, the request won't block waiting on
1852          * other nodes and the -EAGAIN will indicate to the caller that
1853          * this inode is still in use.
1854          */
1855         status = ocfs2_cluster_lock(osb, lockres, level, DLM_LKF_NOQUEUE, 0);
1856 
1857 out:
1858         return status;
1859 }
1860 
1861 /*
1862  * ocfs2_open_unlock unlock PR and EX mode open locks.
1863  */
1864 void ocfs2_open_unlock(struct inode *inode)
1865 {
1866         struct ocfs2_lock_res *lockres = &OCFS2_I(inode)->ip_open_lockres;
1867         struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
1868 
1869         mlog(0, "inode %llu drop open lock\n",
1870              (unsigned long long)OCFS2_I(inode)->ip_blkno);
1871 
1872         if (ocfs2_mount_local(osb))
1873                 goto out;
1874 
1875         if(lockres->l_ro_holders)
1876                 ocfs2_cluster_unlock(osb, lockres, DLM_LOCK_PR);
1877         if(lockres->l_ex_holders)
1878                 ocfs2_cluster_unlock(osb, lockres, DLM_LOCK_EX);
1879 
1880 out:
1881         return;
1882 }
1883 
1884 static int ocfs2_flock_handle_signal(struct ocfs2_lock_res *lockres,
1885                                      int level)
1886 {
1887         int ret;
1888         struct ocfs2_super *osb = ocfs2_get_lockres_osb(lockres);
1889         unsigned long flags;
1890         struct ocfs2_mask_waiter mw;
1891 
1892         ocfs2_init_mask_waiter(&mw);
1893 
1894 retry_cancel:
1895         spin_lock_irqsave(&lockres->l_lock, flags);
1896         if (lockres->l_flags & OCFS2_LOCK_BUSY) {
1897                 ret = ocfs2_prepare_cancel_convert(osb, lockres);
1898                 if (ret) {
1899                         spin_unlock_irqrestore(&lockres->l_lock, flags);
1900                         ret = ocfs2_cancel_convert(osb, lockres);
1901                         if (ret < 0) {
1902                                 mlog_errno(ret);
1903                                 goto out;
1904                         }
1905                         goto retry_cancel;
1906                 }
1907                 lockres_add_mask_waiter(lockres, &mw, OCFS2_LOCK_BUSY, 0);
1908                 spin_unlock_irqrestore(&lockres->l_lock, flags);
1909 
1910                 ocfs2_wait_for_mask(&mw);
1911                 goto retry_cancel;
1912         }
1913 
1914         ret = -ERESTARTSYS;
1915         /*
1916          * We may still have gotten the lock, in which case there's no
1917          * point to restarting the syscall.
1918          */
1919         if (lockres->l_level == level)
1920                 ret = 0;
1921 
1922         mlog(0, "Cancel returning %d. flags: 0x%lx, level: %d, act: %d\n", ret,
1923              lockres->l_flags, lockres->l_level, lockres->l_action);
1924 
1925         spin_unlock_irqrestore(&lockres->l_lock, flags);
1926 
1927 out:
1928         return ret;
1929 }
1930 
1931 /*
1932  * ocfs2_file_lock() and ocfs2_file_unlock() map to a single pair of
1933  * flock() calls. The locking approach this requires is sufficiently
1934  * different from all other cluster lock types that we implement a
1935  * separate path to the "low-level" dlm calls. In particular:
1936  *
1937  * - No optimization of lock levels is done - we take at exactly
1938  *   what's been requested.
1939  *
1940  * - No lock caching is employed. We immediately downconvert to
1941  *   no-lock at unlock time. This also means flock locks never go on
1942  *   the blocking list).
1943  *
1944  * - Since userspace can trivially deadlock itself with flock, we make
1945  *   sure to allow cancellation of a misbehaving applications flock()
1946  *   request.
1947  *
1948  * - Access to any flock lockres doesn't require concurrency, so we
1949  *   can simplify the code by requiring the caller to guarantee
1950  *   serialization of dlmglue flock calls.
1951  */
1952 int ocfs2_file_lock(struct file *file, int ex, int trylock)
1953 {
1954         int ret, level = ex ? DLM_LOCK_EX : DLM_LOCK_PR;
1955         unsigned int lkm_flags = trylock ? DLM_LKF_NOQUEUE : 0;
1956         unsigned long flags;
1957         struct ocfs2_file_private *fp = file->private_data;
1958         struct ocfs2_lock_res *lockres = &fp->fp_flock;
1959         struct ocfs2_super *osb = OCFS2_SB(file->f_mapping->host->i_sb);
1960         struct ocfs2_mask_waiter mw;
1961 
1962         ocfs2_init_mask_waiter(&mw);
1963 
1964         if ((lockres->l_flags & OCFS2_LOCK_BUSY) ||
1965             (lockres->l_level > DLM_LOCK_NL)) {
1966                 mlog(ML_ERROR,
1967                      "File lock \"%s\" has busy or locked state: flags: 0x%lx, "
1968                      "level: %u\n", lockres->l_name, lockres->l_flags,
1969                      lockres->l_level);
1970                 return -EINVAL;
1971         }
1972 
1973         spin_lock_irqsave(&lockres->l_lock, flags);
1974         if (!(lockres->l_flags & OCFS2_LOCK_ATTACHED)) {
1975                 lockres_add_mask_waiter(lockres, &mw, OCFS2_LOCK_BUSY, 0);
1976                 spin_unlock_irqrestore(&lockres->l_lock, flags);
1977 
1978                 /*
1979                  * Get the lock at NLMODE to start - that way we
1980                  * can cancel the upconvert request if need be.
1981                  */
1982                 ret = ocfs2_lock_create(osb, lockres, DLM_LOCK_NL, 0);
1983                 if (ret < 0) {
1984                         mlog_errno(ret);
1985                         goto out;
1986                 }
1987 
1988                 ret = ocfs2_wait_for_mask(&mw);
1989                 if (ret) {
1990                         mlog_errno(ret);
1991                         goto out;
1992                 }
1993                 spin_lock_irqsave(&lockres->l_lock, flags);
1994         }
1995 
1996         lockres->l_action = OCFS2_AST_CONVERT;
1997         lkm_flags |= DLM_LKF_CONVERT;
1998         lockres->l_requested = level;
1999         lockres_or_flags(lockres, OCFS2_LOCK_BUSY);
2000 
2001         lockres_add_mask_waiter(lockres, &mw, OCFS2_LOCK_BUSY, 0);
2002         spin_unlock_irqrestore(&lockres->l_lock, flags);
2003 
2004         ret = ocfs2_dlm_lock(osb->cconn, level, &lockres->l_lksb, lkm_flags,
2005                              lockres->l_name, OCFS2_LOCK_ID_MAX_LEN - 1);
2006         if (ret) {
2007                 if (!trylock || (ret != -EAGAIN)) {
2008                         ocfs2_log_dlm_error("ocfs2_dlm_lock", ret, lockres);
2009                         ret = -EINVAL;
2010                 }
2011 
2012                 ocfs2_recover_from_dlm_error(lockres, 1);
2013                 lockres_remove_mask_waiter(lockres, &mw);
2014                 goto out;
2015         }
2016 
2017         ret = ocfs2_wait_for_mask_interruptible(&mw, lockres);
2018         if (ret == -ERESTARTSYS) {
2019                 /*
2020                  * Userspace can cause deadlock itself with
2021                  * flock(). Current behavior locally is to allow the
2022                  * deadlock, but abort the system call if a signal is
2023                  * received. We follow this example, otherwise a
2024                  * poorly written program could sit in kernel until
2025                  * reboot.
2026                  *
2027                  * Handling this is a bit more complicated for Ocfs2
2028                  * though. We can't exit this function with an
2029                  * outstanding lock request, so a cancel convert is
2030                  * required. We intentionally overwrite 'ret' - if the
2031                  * cancel fails and the lock was granted, it's easier
2032                  * to just bubble success back up to the user.
2033                  */
2034                 ret = ocfs2_flock_handle_signal(lockres, level);
2035         } else if (!ret && (level > lockres->l_level)) {
2036                 /* Trylock failed asynchronously */
2037                 BUG_ON(!trylock);
2038                 ret = -EAGAIN;
2039         }
2040 
2041 out:
2042 
2043         mlog(0, "Lock: \"%s\" ex: %d, trylock: %d, returns: %d\n",
2044              lockres->l_name, ex, trylock, ret);
2045         return ret;
2046 }
2047 
2048 void ocfs2_file_unlock(struct file *file)
2049 {
2050         int ret;
2051         unsigned int gen;
2052         unsigned long flags;
2053         struct ocfs2_file_private *fp = file->private_data;
2054         struct ocfs2_lock_res *lockres = &fp->fp_flock;
2055         struct ocfs2_super *osb = OCFS2_SB(file->f_mapping->host->i_sb);
2056         struct ocfs2_mask_waiter mw;
2057 
2058         ocfs2_init_mask_waiter(&mw);
2059 
2060         if (!(lockres->l_flags & OCFS2_LOCK_ATTACHED))
2061                 return;
2062 
2063         if (lockres->l_level == DLM_LOCK_NL)
2064                 return;
2065 
2066         mlog(0, "Unlock: \"%s\" flags: 0x%lx, level: %d, act: %d\n",
2067              lockres->l_name, lockres->l_flags, lockres->l_level,
2068              lockres->l_action);
2069 
2070         spin_lock_irqsave(&lockres->l_lock, flags);
2071         /*
2072          * Fake a blocking ast for the downconvert code.
2073          */
2074         lockres_or_flags(lockres, OCFS2_LOCK_BLOCKED);
2075         lockres->l_blocking = DLM_LOCK_EX;
2076 
2077         gen = ocfs2_prepare_downconvert(lockres, DLM_LOCK_NL);
2078         lockres_add_mask_waiter(lockres, &mw, OCFS2_LOCK_BUSY, 0);
2079         spin_unlock_irqrestore(&lockres->l_lock, flags);
2080 
2081         ret = ocfs2_downconvert_lock(osb, lockres, DLM_LOCK_NL, 0, gen);
2082         if (ret) {
2083                 mlog_errno(ret);
2084                 return;
2085         }
2086 
2087         ret = ocfs2_wait_for_mask(&mw);
2088         if (ret)
2089                 mlog_errno(ret);
2090 }
2091 
2092 static void ocfs2_downconvert_on_unlock(struct ocfs2_super *osb,
2093                                         struct ocfs2_lock_res *lockres)
2094 {
2095         int kick = 0;
2096 
2097         /* If we know that another node is waiting on our lock, kick
2098          * the downconvert thread * pre-emptively when we reach a release
2099          * condition. */
2100         if (lockres->l_flags & OCFS2_LOCK_BLOCKED) {
2101                 switch(lockres->l_blocking) {
2102                 case DLM_LOCK_EX:
2103                         if (!lockres->l_ex_holders && !lockres->l_ro_holders)
2104                                 kick = 1;
2105                         break;
2106                 case DLM_LOCK_PR:
2107                         if (!lockres->l_ex_holders)
2108                                 kick = 1;
2109                         break;
2110                 default:
2111                         BUG();
2112                 }
2113         }
2114 
2115         if (kick)
2116                 ocfs2_wake_downconvert_thread(osb);
2117 }
2118 
2119 #define OCFS2_SEC_BITS   34
2120 #define OCFS2_SEC_SHIFT  (64 - 34)
2121 #define OCFS2_NSEC_MASK  ((1ULL << OCFS2_SEC_SHIFT) - 1)
2122 
2123 /* LVB only has room for 64 bits of time here so we pack it for
2124  * now. */
2125 static u64 ocfs2_pack_timespec(struct timespec *spec)
2126 {
2127         u64 res;
2128         u64 sec = spec->tv_sec;
2129         u32 nsec = spec->tv_nsec;
2130 
2131         res = (sec << OCFS2_SEC_SHIFT) | (nsec & OCFS2_NSEC_MASK);
2132 
2133         return res;
2134 }
2135 
2136 /* Call this with the lockres locked. I am reasonably sure we don't
2137  * need ip_lock in this function as anyone who would be changing those
2138  * values is supposed to be blocked in ocfs2_inode_lock right now. */
2139 static void __ocfs2_stuff_meta_lvb(struct inode *inode)
2140 {
2141         struct ocfs2_inode_info *oi = OCFS2_I(inode);
2142         struct ocfs2_lock_res *lockres = &oi->ip_inode_lockres;
2143         struct ocfs2_meta_lvb *lvb;
2144 
2145         lvb = ocfs2_dlm_lvb(&lockres->l_lksb);
2146 
2147         /*
2148          * Invalidate the LVB of a deleted inode - this way other
2149          * nodes are forced to go to disk and discover the new inode
2150          * status.
2151          */
2152         if (oi->ip_flags & OCFS2_INODE_DELETED) {
2153                 lvb->lvb_version = 0;
2154                 goto out;
2155         }
2156 
2157         lvb->lvb_version   = OCFS2_LVB_VERSION;
2158         lvb->lvb_isize     = cpu_to_be64(i_size_read(inode));
2159         lvb->lvb_iclusters = cpu_to_be32(oi->ip_clusters);
2160         lvb->lvb_iuid      = cpu_to_be32(i_uid_read(inode));
2161         lvb->lvb_igid      = cpu_to_be32(i_gid_read(inode));
2162         lvb->lvb_imode     = cpu_to_be16(inode->i_mode);
2163         lvb->lvb_inlink    = cpu_to_be16(inode->i_nlink);
2164         lvb->lvb_iatime_packed  =
2165                 cpu_to_be64(ocfs2_pack_timespec(&inode->i_atime));
2166         lvb->lvb_ictime_packed =
2167                 cpu_to_be64(ocfs2_pack_timespec(&inode->i_ctime));
2168         lvb->lvb_imtime_packed =
2169                 cpu_to_be64(ocfs2_pack_timespec(&inode->i_mtime));
2170         lvb->lvb_iattr    = cpu_to_be32(oi->ip_attr);
2171         lvb->lvb_idynfeatures = cpu_to_be16(oi->ip_dyn_features);
2172         lvb->lvb_igeneration = cpu_to_be32(inode->i_generation);
2173 
2174 out:
2175         mlog_meta_lvb(0, lockres);
2176 }
2177 
2178 static void ocfs2_unpack_timespec(struct timespec *spec,
2179                                   u64 packed_time)
2180 {
2181         spec->tv_sec = packed_time >> OCFS2_SEC_SHIFT;
2182         spec->tv_nsec = packed_time & OCFS2_NSEC_MASK;
2183 }
2184 
2185 static void ocfs2_refresh_inode_from_lvb(struct inode *inode)
2186 {
2187         struct ocfs2_inode_info *oi = OCFS2_I(inode);
2188         struct ocfs2_lock_res *lockres = &oi->ip_inode_lockres;
2189         struct ocfs2_meta_lvb *lvb;
2190 
2191         mlog_meta_lvb(0, lockres);
2192 
2193         lvb = ocfs2_dlm_lvb(&lockres->l_lksb);
2194 
2195         /* We're safe here without the lockres lock... */
2196         spin_lock(&oi->ip_lock);
2197         oi->ip_clusters = be32_to_cpu(lvb->lvb_iclusters);
2198         i_size_write(inode, be64_to_cpu(lvb->lvb_isize));
2199 
2200         oi->ip_attr = be32_to_cpu(lvb->lvb_iattr);
2201         oi->ip_dyn_features = be16_to_cpu(lvb->lvb_idynfeatures);
2202         ocfs2_set_inode_flags(inode);
2203 
2204         /* fast-symlinks are a special case */
2205         if (S_ISLNK(inode->i_mode) && !oi->ip_clusters)
2206                 inode->i_blocks = 0;
2207         else
2208                 inode->i_blocks = ocfs2_inode_sector_count(inode);
2209 
2210         i_uid_write(inode, be32_to_cpu(lvb->lvb_iuid));
2211         i_gid_write(inode, be32_to_cpu(lvb->lvb_igid));
2212         inode->i_mode    = be16_to_cpu(lvb->lvb_imode);
2213         set_nlink(inode, be16_to_cpu(lvb->lvb_inlink));
2214         ocfs2_unpack_timespec(&inode->i_atime,
2215                               be64_to_cpu(lvb->lvb_iatime_packed));
2216         ocfs2_unpack_timespec(&inode->i_mtime,
2217                               be64_to_cpu(lvb->lvb_imtime_packed));
2218         ocfs2_unpack_timespec(&inode->i_ctime,
2219                               be64_to_cpu(lvb->lvb_ictime_packed));
2220         spin_unlock(&oi->ip_lock);
2221 }
2222 
2223 static inline int ocfs2_meta_lvb_is_trustable(struct inode *inode,
2224                                               struct ocfs2_lock_res *lockres)
2225 {
2226         struct ocfs2_meta_lvb *lvb = ocfs2_dlm_lvb(&lockres->l_lksb);
2227 
2228         if (ocfs2_dlm_lvb_valid(&lockres->l_lksb)
2229             && lvb->lvb_version == OCFS2_LVB_VERSION
2230             && be32_to_cpu(lvb->lvb_igeneration) == inode->i_generation)
2231                 return 1;
2232         return 0;
2233 }
2234 
2235 /* Determine whether a lock resource needs to be refreshed, and
2236  * arbitrate who gets to refresh it.
2237  *
2238  *   0 means no refresh needed.
2239  *
2240  *   > 0 means you need to refresh this and you MUST call
2241  *   ocfs2_complete_lock_res_refresh afterwards. */
2242 static int ocfs2_should_refresh_lock_res(struct ocfs2_lock_res *lockres)
2243 {
2244         unsigned long flags;
2245         int status = 0;
2246 
2247 refresh_check:
2248         spin_lock_irqsave(&lockres->l_lock, flags);
2249         if (!(lockres->l_flags & OCFS2_LOCK_NEEDS_REFRESH)) {
2250                 spin_unlock_irqrestore(&lockres->l_lock, flags);
2251                 goto bail;
2252         }
2253 
2254         if (lockres->l_flags & OCFS2_LOCK_REFRESHING) {
2255                 spin_unlock_irqrestore(&lockres->l_lock, flags);
2256 
2257                 ocfs2_wait_on_refreshing_lock(lockres);
2258                 goto refresh_check;
2259         }
2260 
2261         /* Ok, I'll be the one to refresh this lock. */
2262         lockres_or_flags(lockres, OCFS2_LOCK_REFRESHING);
2263         spin_unlock_irqrestore(&lockres->l_lock, flags);
2264 
2265         status = 1;
2266 bail:
2267         mlog(0, "status %d\n", status);
2268         return status;
2269 }
2270 
2271 /* If status is non zero, I'll mark it as not being in refresh
2272  * anymroe, but i won't clear the needs refresh flag. */
2273 static inline void ocfs2_complete_lock_res_refresh(struct ocfs2_lock_res *lockres,
2274                                                    int status)
2275 {
2276         unsigned long flags;
2277 
2278         spin_lock_irqsave(&lockres->l_lock, flags);
2279         lockres_clear_flags(lockres, OCFS2_LOCK_REFRESHING);
2280         if (!status)
2281                 lockres_clear_flags(lockres, OCFS2_LOCK_NEEDS_REFRESH);
2282         spin_unlock_irqrestore(&lockres->l_lock, flags);
2283 
2284         wake_up(&lockres->l_event);
2285 }
2286 
2287 /* may or may not return a bh if it went to disk. */
2288 static int ocfs2_inode_lock_update(struct inode *inode,
2289                                   struct buffer_head **bh)
2290 {
2291         int status = 0;
2292         struct ocfs2_inode_info *oi = OCFS2_I(inode);
2293         struct ocfs2_lock_res *lockres = &oi->ip_inode_lockres;
2294         struct ocfs2_dinode *fe;
2295         struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
2296 
2297         if (ocfs2_mount_local(osb))
2298                 goto bail;
2299 
2300         spin_lock(&oi->ip_lock);
2301         if (oi->ip_flags & OCFS2_INODE_DELETED) {
2302                 mlog(0, "Orphaned inode %llu was deleted while we "
2303                      "were waiting on a lock. ip_flags = 0x%x\n",
2304                      (unsigned long long)oi->ip_blkno, oi->ip_flags);
2305                 spin_unlock(&oi->ip_lock);
2306                 status = -ENOENT;
2307                 goto bail;
2308         }
2309         spin_unlock(&oi->ip_lock);
2310 
2311         if (!ocfs2_should_refresh_lock_res(lockres))
2312                 goto bail;
2313 
2314         /* This will discard any caching information we might have had
2315          * for the inode metadata. */
2316         ocfs2_metadata_cache_purge(INODE_CACHE(inode));
2317 
2318         ocfs2_extent_map_trunc(inode, 0);
2319 
2320         if (ocfs2_meta_lvb_is_trustable(inode, lockres)) {
2321                 mlog(0, "Trusting LVB on inode %llu\n",
2322                      (unsigned long long)oi->ip_blkno);
2323                 ocfs2_refresh_inode_from_lvb(inode);
2324         } else {
2325                 /* Boo, we have to go to disk. */
2326                 /* read bh, cast, ocfs2_refresh_inode */
2327                 status = ocfs2_read_inode_block(inode, bh);
2328                 if (status < 0) {
2329                         mlog_errno(status);
2330                         goto bail_refresh;
2331                 }
2332                 fe = (struct ocfs2_dinode *) (*bh)->b_data;
2333 
2334                 /* This is a good chance to make sure we're not
2335                  * locking an invalid object.  ocfs2_read_inode_block()
2336                  * already checked that the inode block is sane.
2337                  *
2338                  * We bug on a stale inode here because we checked
2339                  * above whether it was wiped from disk. The wiping
2340                  * node provides a guarantee that we receive that
2341                  * message and can mark the inode before dropping any
2342                  * locks associated with it. */
2343                 mlog_bug_on_msg(inode->i_generation !=
2344                                 le32_to_cpu(fe->i_generation),
2345                                 "Invalid dinode %llu disk generation: %u "
2346                                 "inode->i_generation: %u\n",
2347                                 (unsigned long long)oi->ip_blkno,
2348                                 le32_to_cpu(fe->i_generation),
2349                                 inode->i_generation);
2350                 mlog_bug_on_msg(le64_to_cpu(fe->i_dtime) ||
2351                                 !(fe->i_flags & cpu_to_le32(OCFS2_VALID_FL)),
2352                                 "Stale dinode %llu dtime: %llu flags: 0x%x\n",
2353                                 (unsigned long long)oi->ip_blkno,
2354                                 (unsigned long long)le64_to_cpu(fe->i_dtime),
2355                                 le32_to_cpu(fe->i_flags));
2356 
2357                 ocfs2_refresh_inode(inode, fe);
2358                 ocfs2_track_lock_refresh(lockres);
2359         }
2360 
2361         status = 0;
2362 bail_refresh:
2363         ocfs2_complete_lock_res_refresh(lockres, status);
2364 bail:
2365         return status;
2366 }
2367 
2368 static int ocfs2_assign_bh(struct inode *inode,
2369                            struct buffer_head **ret_bh,
2370                            struct buffer_head *passed_bh)
2371 {
2372         int status;
2373 
2374         if (passed_bh) {
2375                 /* Ok, the update went to disk for us, use the
2376                  * returned bh. */
2377                 *ret_bh = passed_bh;
2378                 get_bh(*ret_bh);
2379 
2380                 return 0;
2381         }
2382 
2383         status = ocfs2_read_inode_block(inode, ret_bh);
2384         if (status < 0)
2385                 mlog_errno(status);
2386 
2387         return status;
2388 }
2389 
2390 /*
2391  * returns < 0 error if the callback will never be called, otherwise
2392  * the result of the lock will be communicated via the callback.
2393  */
2394 int ocfs2_inode_lock_full_nested(struct inode *inode,
2395                                  struct buffer_head **ret_bh,
2396                                  int ex,
2397                                  int arg_flags,
2398                                  int subclass)
2399 {
2400         int status, level, acquired;
2401         u32 dlm_flags;
2402         struct ocfs2_lock_res *lockres = NULL;
2403         struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
2404         struct buffer_head *local_bh = NULL;
2405 
2406         mlog(0, "inode %llu, take %s META lock\n",
2407              (unsigned long long)OCFS2_I(inode)->ip_blkno,
2408              ex ? "EXMODE" : "PRMODE");
2409 
2410         status = 0;
2411         acquired = 0;
2412         /* We'll allow faking a readonly metadata lock for
2413          * rodevices. */
2414         if (ocfs2_is_hard_readonly(osb)) {
2415                 if (ex)
2416                         status = -EROFS;
2417                 goto getbh;
2418         }
2419 
2420         if ((arg_flags & OCFS2_META_LOCK_GETBH) ||
2421             ocfs2_mount_local(osb))
2422                 goto update;
2423 
2424         if (!(arg_flags & OCFS2_META_LOCK_RECOVERY))
2425                 ocfs2_wait_for_recovery(osb);
2426 
2427         lockres = &OCFS2_I(inode)->ip_inode_lockres;
2428         level = ex ? DLM_LOCK_EX : DLM_LOCK_PR;
2429         dlm_flags = 0;
2430         if (arg_flags & OCFS2_META_LOCK_NOQUEUE)
2431                 dlm_flags |= DLM_LKF_NOQUEUE;
2432 
2433         status = __ocfs2_cluster_lock(osb, lockres, level, dlm_flags,
2434                                       arg_flags, subclass, _RET_IP_);
2435         if (status < 0) {
2436                 if (status != -EAGAIN)
2437                         mlog_errno(status);
2438                 goto bail;
2439         }
2440 
2441         /* Notify the error cleanup path to drop the cluster lock. */
2442         acquired = 1;
2443 
2444         /* We wait twice because a node may have died while we were in
2445          * the lower dlm layers. The second time though, we've
2446          * committed to owning this lock so we don't allow signals to
2447          * abort the operation. */
2448         if (!(arg_flags & OCFS2_META_LOCK_RECOVERY))
2449                 ocfs2_wait_for_recovery(osb);
2450 
2451 update:
2452         /*
2453          * We only see this flag if we're being called from
2454          * ocfs2_read_locked_inode(). It means we're locking an inode
2455          * which hasn't been populated yet, so clear the refresh flag
2456          * and let the caller handle it.
2457          */
2458         if (inode->i_state & I_NEW) {
2459                 status = 0;
2460                 if (lockres)
2461                         ocfs2_complete_lock_res_refresh(lockres, 0);
2462                 goto bail;
2463         }
2464 
2465         /* This is fun. The caller may want a bh back, or it may
2466          * not. ocfs2_inode_lock_update definitely wants one in, but
2467          * may or may not read one, depending on what's in the
2468          * LVB. The result of all of this is that we've *only* gone to
2469          * disk if we have to, so the complexity is worthwhile. */
2470         status = ocfs2_inode_lock_update(inode, &local_bh);
2471         if (status < 0) {
2472                 if (status != -ENOENT)
2473                         mlog_errno(status);
2474                 goto bail;
2475         }
2476 getbh:
2477         if (ret_bh) {
2478                 status = ocfs2_assign_bh(inode, ret_bh, local_bh);
2479                 if (status < 0) {
2480                         mlog_errno(status);
2481                         goto bail;
2482                 }
2483         }
2484 
2485 bail:
2486         if (status < 0) {
2487                 if (ret_bh && (*ret_bh)) {
2488                         brelse(*ret_bh);
2489                         *ret_bh = NULL;
2490                 }
2491                 if (acquired)
2492                         ocfs2_inode_unlock(inode, ex);
2493         }
2494 
2495         if (local_bh)
2496                 brelse(local_bh);
2497 
2498         return status;
2499 }
2500 
2501 /*
2502  * This is working around a lock inversion between tasks acquiring DLM
2503  * locks while holding a page lock and the downconvert thread which
2504  * blocks dlm lock acquiry while acquiring page locks.
2505  *
2506  * ** These _with_page variantes are only intended to be called from aop
2507  * methods that hold page locks and return a very specific *positive* error
2508  * code that aop methods pass up to the VFS -- test for errors with != 0. **
2509  *
2510  * The DLM is called such that it returns -EAGAIN if it would have
2511  * blocked waiting for the downconvert thread.  In that case we unlock
2512  * our page so the downconvert thread can make progress.  Once we've
2513  * done this we have to return AOP_TRUNCATED_PAGE so the aop method
2514  * that called us can bubble that back up into the VFS who will then
2515  * immediately retry the aop call.
2516  */
2517 int ocfs2_inode_lock_with_page(struct inode *inode,
2518                               struct buffer_head **ret_bh,
2519                               int ex,
2520                               struct page *page)
2521 {
2522         int ret;
2523 
2524         ret = ocfs2_inode_lock_full(inode, ret_bh, ex, OCFS2_LOCK_NONBLOCK);
2525         if (ret == -EAGAIN) {
2526                 unlock_page(page);
2527                 /*
2528                  * If we can't get inode lock immediately, we should not return
2529                  * directly here, since this will lead to a softlockup problem.
2530                  * The method is to get a blocking lock and immediately unlock
2531                  * before returning, this can avoid CPU resource waste due to
2532                  * lots of retries, and benefits fairness in getting lock.
2533                  */
2534                 if (ocfs2_inode_lock(inode, ret_bh, ex) == 0)
2535                         ocfs2_inode_unlock(inode, ex);
2536                 ret = AOP_TRUNCATED_PAGE;
2537         }
2538 
2539         return ret;
2540 }
2541 
2542 int ocfs2_inode_lock_atime(struct inode *inode,
2543                           struct vfsmount *vfsmnt,
2544                           int *level, int wait)
2545 {
2546         int ret;
2547 
2548         if (wait)
2549                 ret = ocfs2_inode_lock(inode, NULL, 0);
2550         else
2551                 ret = ocfs2_try_inode_lock(inode, NULL, 0);
2552 
2553         if (ret < 0) {
2554                 if (ret != -EAGAIN)
2555                         mlog_errno(ret);
2556                 return ret;
2557         }
2558 
2559         /*
2560          * If we should update atime, we will get EX lock,
2561          * otherwise we just get PR lock.
2562          */
2563         if (ocfs2_should_update_atime(inode, vfsmnt)) {
2564                 struct buffer_head *bh = NULL;
2565 
2566                 ocfs2_inode_unlock(inode, 0);
2567                 if (wait)
2568                         ret = ocfs2_inode_lock(inode, &bh, 1);
2569                 else
2570                         ret = ocfs2_try_inode_lock(inode, &bh, 1);
2571 
2572                 if (ret < 0) {
2573                         if (ret != -EAGAIN)
2574                                 mlog_errno(ret);
2575                         return ret;
2576                 }
2577                 *level = 1;
2578                 if (ocfs2_should_update_atime(inode, vfsmnt))
2579                         ocfs2_update_inode_atime(inode, bh);
2580                 if (bh)
2581                         brelse(bh);
2582         } else
2583                 *level = 0;
2584 
2585         return ret;
2586 }
2587 
2588 void ocfs2_inode_unlock(struct inode *inode,
2589                        int ex)
2590 {
2591         int level = ex ? DLM_LOCK_EX : DLM_LOCK_PR;
2592         struct ocfs2_lock_res *lockres = &OCFS2_I(inode)->ip_inode_lockres;
2593         struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
2594 
2595         mlog(0, "inode %llu drop %s META lock\n",
2596              (unsigned long long)OCFS2_I(inode)->ip_blkno,
2597              ex ? "EXMODE" : "PRMODE");
2598 
2599         if (!ocfs2_is_hard_readonly(osb) &&
2600             !ocfs2_mount_local(osb))
2601                 ocfs2_cluster_unlock(osb, lockres, level);
2602 }
2603 
2604 /*
2605  * This _tracker variantes are introduced to deal with the recursive cluster
2606  * locking issue. The idea is to keep track of a lock holder on the stack of
2607  * the current process. If there's a lock holder on the stack, we know the
2608  * task context is already protected by cluster locking. Currently, they're
2609  * used in some VFS entry routines.
2610  *
2611  * return < 0 on error, return == 0 if there's no lock holder on the stack
2612  * before this call, return == 1 if this call would be a recursive locking.
2613  */
2614 int ocfs2_inode_lock_tracker(struct inode *inode,
2615                              struct buffer_head **ret_bh,
2616                              int ex,
2617                              struct ocfs2_lock_holder *oh)
2618 {
2619         int status;
2620         int arg_flags = 0, has_locked;
2621         struct ocfs2_lock_res *lockres;
2622 
2623         lockres = &OCFS2_I(inode)->ip_inode_lockres;
2624         has_locked = ocfs2_is_locked_by_me(lockres);
2625         /* Just get buffer head if the cluster lock has been taken */
2626         if (has_locked)
2627                 arg_flags = OCFS2_META_LOCK_GETBH;
2628 
2629         if (likely(!has_locked || ret_bh)) {
2630                 status = ocfs2_inode_lock_full(inode, ret_bh, ex, arg_flags);
2631                 if (status < 0) {
2632                         if (status != -ENOENT)
2633                                 mlog_errno(status);
2634                         return status;
2635                 }
2636         }
2637         if (!has_locked)
2638                 ocfs2_add_holder(lockres, oh);
2639 
2640         return has_locked;
2641 }
2642 
2643 void ocfs2_inode_unlock_tracker(struct inode *inode,
2644                                 int ex,
2645                                 struct ocfs2_lock_holder *oh,
2646                                 int had_lock)
2647 {
2648         struct ocfs2_lock_res *lockres;
2649 
2650         lockres = &OCFS2_I(inode)->ip_inode_lockres;
2651         /* had_lock means that the currect process already takes the cluster
2652          * lock previously. If had_lock is 1, we have nothing to do here, and
2653          * it will get unlocked where we got the lock.
2654          */
2655         if (!had_lock) {
2656                 ocfs2_remove_holder(lockres, oh);
2657                 ocfs2_inode_unlock(inode, ex);
2658         }
2659 }
2660 
2661 int ocfs2_orphan_scan_lock(struct ocfs2_super *osb, u32 *seqno)
2662 {
2663         struct ocfs2_lock_res *lockres;
2664         struct ocfs2_orphan_scan_lvb *lvb;
2665         int status = 0;
2666 
2667         if (ocfs2_is_hard_readonly(osb))
2668                 return -EROFS;
2669 
2670         if (ocfs2_mount_local(osb))
2671                 return 0;
2672 
2673         lockres = &osb->osb_orphan_scan.os_lockres;
2674         status = ocfs2_cluster_lock(osb, lockres, DLM_LOCK_EX, 0, 0);
2675         if (status < 0)
2676                 return status;
2677 
2678         lvb = ocfs2_dlm_lvb(&lockres->l_lksb);
2679         if (ocfs2_dlm_lvb_valid(&lockres->l_lksb) &&
2680             lvb->lvb_version == OCFS2_ORPHAN_LVB_VERSION)
2681                 *seqno = be32_to_cpu(lvb->lvb_os_seqno);
2682         else
2683                 *seqno = osb->osb_orphan_scan.os_seqno + 1;
2684 
2685         return status;
2686 }
2687 
2688 void ocfs2_orphan_scan_unlock(struct ocfs2_super *osb, u32 seqno)
2689 {
2690         struct ocfs2_lock_res *lockres;
2691         struct ocfs2_orphan_scan_lvb *lvb;
2692 
2693         if (!ocfs2_is_hard_readonly(osb) && !ocfs2_mount_local(osb)) {
2694                 lockres = &osb->osb_orphan_scan.os_lockres;
2695                 lvb = ocfs2_dlm_lvb(&lockres->l_lksb);
2696                 lvb->lvb_version = OCFS2_ORPHAN_LVB_VERSION;
2697                 lvb->lvb_os_seqno = cpu_to_be32(seqno);
2698                 ocfs2_cluster_unlock(osb, lockres, DLM_LOCK_EX);
2699         }
2700 }
2701 
2702 int ocfs2_super_lock(struct ocfs2_super *osb,
2703                      int ex)
2704 {
2705         int status = 0;
2706         int level = ex ? DLM_LOCK_EX : DLM_LOCK_PR;
2707         struct ocfs2_lock_res *lockres = &osb->osb_super_lockres;
2708 
2709         if (ocfs2_is_hard_readonly(osb))
2710                 return -EROFS;
2711 
2712         if (ocfs2_mount_local(osb))
2713                 goto bail;
2714 
2715         status = ocfs2_cluster_lock(osb, lockres, level, 0, 0);
2716         if (status < 0) {
2717                 mlog_errno(status);
2718                 goto bail;
2719         }
2720 
2721         /* The super block lock path is really in the best position to
2722          * know when resources covered by the lock need to be
2723          * refreshed, so we do it here. Of course, making sense of
2724          * everything is up to the caller :) */
2725         status = ocfs2_should_refresh_lock_res(lockres);
2726         if (status) {
2727                 status = ocfs2_refresh_slot_info(osb);
2728 
2729                 ocfs2_complete_lock_res_refresh(lockres, status);
2730 
2731                 if (status < 0) {
2732                         ocfs2_cluster_unlock(osb, lockres, level);
2733                         mlog_errno(status);
2734                 }
2735                 ocfs2_track_lock_refresh(lockres);
2736         }
2737 bail:
2738         return status;
2739 }
2740 
2741 void ocfs2_super_unlock(struct ocfs2_super *osb,
2742                         int ex)
2743 {
2744         int level = ex ? DLM_LOCK_EX : DLM_LOCK_PR;
2745         struct ocfs2_lock_res *lockres = &osb->osb_super_lockres;
2746 
2747         if (!ocfs2_mount_local(osb))
2748                 ocfs2_cluster_unlock(osb, lockres, level);
2749 }
2750 
2751 int ocfs2_rename_lock(struct ocfs2_super *osb)
2752 {
2753         int status;
2754         struct ocfs2_lock_res *lockres = &osb->osb_rename_lockres;
2755 
2756         if (ocfs2_is_hard_readonly(osb))
2757                 return -EROFS;
2758 
2759         if (ocfs2_mount_local(osb))
2760                 return 0;
2761 
2762         status = ocfs2_cluster_lock(osb, lockres, DLM_LOCK_EX, 0, 0);
2763         if (status < 0)
2764                 mlog_errno(status);
2765 
2766         return status;
2767 }
2768 
2769 void ocfs2_rename_unlock(struct ocfs2_super *osb)
2770 {
2771         struct ocfs2_lock_res *lockres = &osb->osb_rename_lockres;
2772 
2773         if (!ocfs2_mount_local(osb))
2774                 ocfs2_cluster_unlock(osb, lockres, DLM_LOCK_EX);
2775 }
2776 
2777 int ocfs2_nfs_sync_lock(struct ocfs2_super *osb, int ex)
2778 {
2779         int status;
2780         struct ocfs2_lock_res *lockres = &osb->osb_nfs_sync_lockres;
2781 
2782         if (ocfs2_is_hard_readonly(osb))
2783                 return -EROFS;
2784 
2785         if (ocfs2_mount_local(osb))
2786                 return 0;
2787 
2788         status = ocfs2_cluster_lock(osb, lockres, ex ? LKM_EXMODE : LKM_PRMODE,
2789                                     0, 0);
2790         if (status < 0)
2791                 mlog(ML_ERROR, "lock on nfs sync lock failed %d\n", status);
2792 
2793         return status;
2794 }
2795 
2796 void ocfs2_nfs_sync_unlock(struct ocfs2_super *osb, int ex)
2797 {
2798         struct ocfs2_lock_res *lockres = &osb->osb_nfs_sync_lockres;
2799 
2800         if (!ocfs2_mount_local(osb))
2801                 ocfs2_cluster_unlock(osb, lockres,
2802                                      ex ? LKM_EXMODE : LKM_PRMODE);
2803 }
2804 
2805 int ocfs2_trim_fs_lock(struct ocfs2_super *osb,
2806                        struct ocfs2_trim_fs_info *info, int trylock)
2807 {
2808         int status;
2809         struct ocfs2_trim_fs_lvb *lvb;
2810         struct ocfs2_lock_res *lockres = &osb->osb_trim_fs_lockres;
2811 
2812         if (info)
2813                 info->tf_valid = 0;
2814 
2815         if (ocfs2_is_hard_readonly(osb))
2816                 return -EROFS;
2817 
2818         if (ocfs2_mount_local(osb))
2819                 return 0;
2820 
2821         status = ocfs2_cluster_lock(osb, lockres, DLM_LOCK_EX,
2822                                     trylock ? DLM_LKF_NOQUEUE : 0, 0);
2823         if (status < 0) {
2824                 if (status != -EAGAIN)
2825                         mlog_errno(status);
2826                 return status;
2827         }
2828 
2829         if (info) {
2830                 lvb = ocfs2_dlm_lvb(&lockres->l_lksb);
2831                 if (ocfs2_dlm_lvb_valid(&lockres->l_lksb) &&
2832                     lvb->lvb_version == OCFS2_TRIMFS_LVB_VERSION) {
2833                         info->tf_valid = 1;
2834                         info->tf_success = lvb->lvb_success;
2835                         info->tf_nodenum = be32_to_cpu(lvb->lvb_nodenum);
2836                         info->tf_start = be64_to_cpu(lvb->lvb_start);
2837                         info->tf_len = be64_to_cpu(lvb->lvb_len);
2838                         info->tf_minlen = be64_to_cpu(lvb->lvb_minlen);
2839                         info->tf_trimlen = be64_to_cpu(lvb->lvb_trimlen);
2840                 }
2841         }
2842 
2843         return status;
2844 }
2845 
2846 void ocfs2_trim_fs_unlock(struct ocfs2_super *osb,
2847                           struct ocfs2_trim_fs_info *info)
2848 {
2849         struct ocfs2_trim_fs_lvb *lvb;
2850         struct ocfs2_lock_res *lockres = &osb->osb_trim_fs_lockres;
2851 
2852         if (ocfs2_mount_local(osb))
2853                 return;
2854 
2855         if (info) {
2856                 lvb = ocfs2_dlm_lvb(&lockres->l_lksb);
2857                 lvb->lvb_version = OCFS2_TRIMFS_LVB_VERSION;
2858                 lvb->lvb_success = info->tf_success;
2859                 lvb->lvb_nodenum = cpu_to_be32(info->tf_nodenum);
2860                 lvb->lvb_start = cpu_to_be64(info->tf_start);
2861                 lvb->lvb_len = cpu_to_be64(info->tf_len);
2862                 lvb->lvb_minlen = cpu_to_be64(info->tf_minlen);
2863                 lvb->lvb_trimlen = cpu_to_be64(info->tf_trimlen);
2864         }
2865 
2866         ocfs2_cluster_unlock(osb, lockres, DLM_LOCK_EX);
2867 }
2868 
2869 int ocfs2_dentry_lock(struct dentry *dentry, int ex)
2870 {
2871         int ret;
2872         int level = ex ? DLM_LOCK_EX : DLM_LOCK_PR;
2873         struct ocfs2_dentry_lock *dl = dentry->d_fsdata;
2874         struct ocfs2_super *osb = OCFS2_SB(dentry->d_sb);
2875 
2876         BUG_ON(!dl);
2877 
2878         if (ocfs2_is_hard_readonly(osb)) {
2879                 if (ex)
2880                         return -EROFS;
2881                 return 0;
2882         }
2883 
2884         if (ocfs2_mount_local(osb))
2885                 return 0;
2886 
2887         ret = ocfs2_cluster_lock(osb, &dl->dl_lockres, level, 0, 0);
2888         if (ret < 0)
2889                 mlog_errno(ret);
2890 
2891         return ret;
2892 }
2893 
2894 void ocfs2_dentry_unlock(struct dentry *dentry, int ex)
2895 {
2896         int level = ex ? DLM_LOCK_EX : DLM_LOCK_PR;
2897         struct ocfs2_dentry_lock *dl = dentry->d_fsdata;
2898         struct ocfs2_super *osb = OCFS2_SB(dentry->d_sb);
2899 
2900         if (!ocfs2_is_hard_readonly(osb) && !ocfs2_mount_local(osb))
2901                 ocfs2_cluster_unlock(osb, &dl->dl_lockres, level);
2902 }
2903 
2904 /* Reference counting of the dlm debug structure. We want this because
2905  * open references on the debug inodes can live on after a mount, so
2906  * we can't rely on the ocfs2_super to always exist. */
2907 static void ocfs2_dlm_debug_free(struct kref *kref)
2908 {
2909         struct ocfs2_dlm_debug *dlm_debug;
2910 
2911         dlm_debug = container_of(kref, struct ocfs2_dlm_debug, d_refcnt);
2912 
2913         kfree(dlm_debug);
2914 }
2915 
2916 void ocfs2_put_dlm_debug(struct ocfs2_dlm_debug *dlm_debug)
2917 {
2918         if (dlm_debug)
2919                 kref_put(&dlm_debug->d_refcnt, ocfs2_dlm_debug_free);
2920 }
2921 
2922 static void ocfs2_get_dlm_debug(struct ocfs2_dlm_debug *debug)
2923 {
2924         kref_get(&debug->d_refcnt);
2925 }
2926 
2927 struct ocfs2_dlm_debug *ocfs2_new_dlm_debug(void)
2928 {
2929         struct ocfs2_dlm_debug *dlm_debug;
2930 
2931         dlm_debug = kmalloc(sizeof(struct ocfs2_dlm_debug), GFP_KERNEL);
2932         if (!dlm_debug) {
2933                 mlog_errno(-ENOMEM);
2934                 goto out;
2935         }
2936 
2937         kref_init(&dlm_debug->d_refcnt);
2938         INIT_LIST_HEAD(&dlm_debug->d_lockres_tracking);
2939         dlm_debug->d_locking_state = NULL;
2940 out:
2941         return dlm_debug;
2942 }
2943 
2944 /* Access to this is arbitrated for us via seq_file->sem. */
2945 struct ocfs2_dlm_seq_priv {
2946         struct ocfs2_dlm_debug *p_dlm_debug;
2947         struct ocfs2_lock_res p_iter_res;
2948         struct ocfs2_lock_res p_tmp_res;
2949 };
2950 
2951 static struct ocfs2_lock_res *ocfs2_dlm_next_res(struct ocfs2_lock_res *start,
2952                                                  struct ocfs2_dlm_seq_priv *priv)
2953 {
2954         struct ocfs2_lock_res *iter, *ret = NULL;
2955         struct ocfs2_dlm_debug *dlm_debug = priv->p_dlm_debug;
2956 
2957         assert_spin_locked(&ocfs2_dlm_tracking_lock);
2958 
2959         list_for_each_entry(iter, &start->l_debug_list, l_debug_list) {
2960                 /* discover the head of the list */
2961                 if (&iter->l_debug_list == &dlm_debug->d_lockres_tracking) {
2962                         mlog(0, "End of list found, %p\n", ret);
2963                         break;
2964                 }
2965 
2966                 /* We track our "dummy" iteration lockres' by a NULL
2967                  * l_ops field. */
2968                 if (iter->l_ops != NULL) {
2969                         ret = iter;
2970                         break;
2971                 }
2972         }
2973 
2974         return ret;
2975 }
2976 
2977 static void *ocfs2_dlm_seq_start(struct seq_file *m, loff_t *pos)
2978 {
2979         struct ocfs2_dlm_seq_priv *priv = m->private;
2980         struct ocfs2_lock_res *iter;
2981 
2982         spin_lock(&ocfs2_dlm_tracking_lock);
2983         iter = ocfs2_dlm_next_res(&priv->p_iter_res, priv);
2984         if (iter) {
2985                 /* Since lockres' have the lifetime of their container
2986                  * (which can be inodes, ocfs2_supers, etc) we want to
2987                  * copy this out to a temporary lockres while still
2988                  * under the spinlock. Obviously after this we can't
2989                  * trust any pointers on the copy returned, but that's
2990                  * ok as the information we want isn't typically held
2991                  * in them. */
2992                 priv->p_tmp_res = *iter;
2993                 iter = &priv->p_tmp_res;
2994         }
2995         spin_unlock(&ocfs2_dlm_tracking_lock);
2996 
2997         return iter;
2998 }
2999 
3000 static void ocfs2_dlm_seq_stop(struct seq_file *m, void *v)
3001 {
3002 }
3003 
3004 static void *ocfs2_dlm_seq_next(struct seq_file *m, void *v, loff_t *pos)
3005 {
3006         struct ocfs2_dlm_seq_priv *priv = m->private;
3007         struct ocfs2_lock_res *iter = v;
3008         struct ocfs2_lock_res *dummy = &priv->p_iter_res;
3009 
3010         spin_lock(&ocfs2_dlm_tracking_lock);
3011         iter = ocfs2_dlm_next_res(iter, priv);
3012         list_del_init(&dummy->l_debug_list);
3013         if (iter) {
3014                 list_add(&dummy->l_debug_list, &iter->l_debug_list);
3015                 priv->p_tmp_res = *iter;
3016                 iter = &priv->p_tmp_res;
3017         }
3018         spin_unlock(&ocfs2_dlm_tracking_lock);
3019 
3020         return iter;
3021 }
3022 
3023 /*
3024  * Version is used by debugfs.ocfs2 to determine the format being used
3025  *
3026  * New in version 2
3027  *      - Lock stats printed
3028  * New in version 3
3029  *      - Max time in lock stats is in usecs (instead of nsecs)
3030  */
3031 #define OCFS2_DLM_DEBUG_STR_VERSION 3
3032 static int ocfs2_dlm_seq_show(struct seq_file *m, void *v)
3033 {
3034         int i;
3035         char *lvb;
3036         struct ocfs2_lock_res *lockres = v;
3037 
3038         if (!lockres)
3039                 return -EINVAL;
3040 
3041         seq_printf(m, "0x%x\t", OCFS2_DLM_DEBUG_STR_VERSION);
3042 
3043         if (lockres->l_type == OCFS2_LOCK_TYPE_DENTRY)
3044                 seq_printf(m, "%.*s%08x\t", OCFS2_DENTRY_LOCK_INO_START - 1,
3045                            lockres->l_name,
3046                            (unsigned int)ocfs2_get_dentry_lock_ino(lockres));
3047         else
3048                 seq_printf(m, "%.*s\t", OCFS2_LOCK_ID_MAX_LEN, lockres->l_name);
3049 
3050         seq_printf(m, "%d\t"
3051                    "0x%lx\t"
3052                    "0x%x\t"
3053                    "0x%x\t"
3054                    "%u\t"
3055                    "%u\t"
3056                    "%d\t"
3057                    "%d\t",
3058                    lockres->l_level,
3059                    lockres->l_flags,
3060                    lockres->l_action,
3061                    lockres->l_unlock_action,
3062                    lockres->l_ro_holders,
3063                    lockres->l_ex_holders,
3064                    lockres->l_requested,
3065                    lockres->l_blocking);
3066 
3067         /* Dump the raw LVB */
3068         lvb = ocfs2_dlm_lvb(&lockres->l_lksb);
3069         for(i = 0; i < DLM_LVB_LEN; i++)
3070                 seq_printf(m, "0x%x\t", lvb[i]);
3071 
3072 #ifdef CONFIG_OCFS2_FS_STATS
3073 # define lock_num_prmode(_l)            ((_l)->l_lock_prmode.ls_gets)
3074 # define lock_num_exmode(_l)            ((_l)->l_lock_exmode.ls_gets)
3075 # define lock_num_prmode_failed(_l)     ((_l)->l_lock_prmode.ls_fail)
3076 # define lock_num_exmode_failed(_l)     ((_l)->l_lock_exmode.ls_fail)
3077 # define lock_total_prmode(_l)          ((_l)->l_lock_prmode.ls_total)
3078 # define lock_total_exmode(_l)          ((_l)->l_lock_exmode.ls_total)
3079 # define lock_max_prmode(_l)            ((_l)->l_lock_prmode.ls_max)
3080 # define lock_max_exmode(_l)            ((_l)->l_lock_exmode.ls_max)
3081 # define lock_refresh(_l)               ((_l)->l_lock_refresh)
3082 #else
3083 # define lock_num_prmode(_l)            (0)
3084 # define lock_num_exmode(_l)            (0)
3085 # define lock_num_prmode_failed(_l)     (0)
3086 # define lock_num_exmode_failed(_l)     (0)
3087 # define lock_total_prmode(_l)          (0ULL)
3088 # define lock_total_exmode(_l)          (0ULL)
3089 # define lock_max_prmode(_l)            (0)
3090 # define lock_max_exmode(_l)            (0)
3091 # define lock_refresh(_l)               (0)
3092 #endif
3093         /* The following seq_print was added in version 2 of this output */
3094         seq_printf(m, "%u\t"
3095                    "%u\t"
3096                    "%u\t"
3097                    "%u\t"
3098                    "%llu\t"
3099                    "%llu\t"
3100                    "%u\t"
3101                    "%u\t"
3102                    "%u\t",
3103                    lock_num_prmode(lockres),
3104                    lock_num_exmode(lockres),
3105                    lock_num_prmode_failed(lockres),
3106                    lock_num_exmode_failed(lockres),
3107                    lock_total_prmode(lockres),
3108                    lock_total_exmode(lockres),
3109                    lock_max_prmode(lockres),
3110                    lock_max_exmode(lockres),
3111                    lock_refresh(lockres));
3112 
3113         /* End the line */
3114         seq_printf(m, "\n");
3115         return 0;
3116 }
3117 
3118 static const struct seq_operations ocfs2_dlm_seq_ops = {
3119         .start =        ocfs2_dlm_seq_start,
3120         .stop =         ocfs2_dlm_seq_stop,
3121         .next =         ocfs2_dlm_seq_next,
3122         .show =         ocfs2_dlm_seq_show,
3123 };
3124 
3125 static int ocfs2_dlm_debug_release(struct inode *inode, struct file *file)
3126 {
3127         struct seq_file *seq = file->private_data;
3128         struct ocfs2_dlm_seq_priv *priv = seq->private;
3129         struct ocfs2_lock_res *res = &priv->p_iter_res;
3130 
3131         ocfs2_remove_lockres_tracking(res);
3132         ocfs2_put_dlm_debug(priv->p_dlm_debug);
3133         return seq_release_private(inode, file);
3134 }
3135 
3136 static int ocfs2_dlm_debug_open(struct inode *inode, struct file *file)
3137 {
3138         struct ocfs2_dlm_seq_priv *priv;
3139         struct ocfs2_super *osb;
3140 
3141         priv = __seq_open_private(file, &ocfs2_dlm_seq_ops, sizeof(*priv));
3142         if (!priv) {
3143                 mlog_errno(-ENOMEM);
3144                 return -ENOMEM;
3145         }
3146 
3147         osb = inode->i_private;
3148         ocfs2_get_dlm_debug(osb->osb_dlm_debug);
3149         priv->p_dlm_debug = osb->osb_dlm_debug;
3150         INIT_LIST_HEAD(&priv->p_iter_res.l_debug_list);
3151 
3152         ocfs2_add_lockres_tracking(&priv->p_iter_res,
3153                                    priv->p_dlm_debug);
3154 
3155         return 0;
3156 }
3157 
3158 static const struct file_operations ocfs2_dlm_debug_fops = {
3159         .open =         ocfs2_dlm_debug_open,
3160         .release =      ocfs2_dlm_debug_release,
3161         .read =         seq_read,
3162         .llseek =       seq_lseek,
3163 };
3164 
3165 static int ocfs2_dlm_init_debug(struct ocfs2_super *osb)
3166 {
3167         int ret = 0;
3168         struct ocfs2_dlm_debug *dlm_debug = osb->osb_dlm_debug;
3169 
3170         dlm_debug->d_locking_state = debugfs_create_file("locking_state",
3171                                                          S_IFREG|S_IRUSR,
3172                                                          osb->osb_debug_root,
3173                                                          osb,
3174                                                          &ocfs2_dlm_debug_fops);
3175         if (!dlm_debug->d_locking_state) {
3176                 ret = -EINVAL;
3177                 mlog(ML_ERROR,
3178                      "Unable to create locking state debugfs file.\n");
3179                 goto out;
3180         }
3181 
3182         ocfs2_get_dlm_debug(dlm_debug);
3183 out:
3184         return ret;
3185 }
3186 
3187 static void ocfs2_dlm_shutdown_debug(struct ocfs2_super *osb)
3188 {
3189         struct ocfs2_dlm_debug *dlm_debug = osb->osb_dlm_debug;
3190 
3191         if (dlm_debug) {
3192                 debugfs_remove(dlm_debug->d_locking_state);
3193                 ocfs2_put_dlm_debug(dlm_debug);
3194         }
3195 }
3196 
3197 int ocfs2_dlm_init(struct ocfs2_super *osb)
3198 {
3199         int status = 0;
3200         struct ocfs2_cluster_connection *conn = NULL;
3201 
3202         if (ocfs2_mount_local(osb)) {
3203                 osb->node_num = 0;
3204                 goto local;
3205         }
3206 
3207         status = ocfs2_dlm_init_debug(osb);
3208         if (status < 0) {
3209                 mlog_errno(status);
3210                 goto bail;
3211         }
3212 
3213         /* launch downconvert thread */
3214         osb->dc_task = kthread_run(ocfs2_downconvert_thread, osb, "ocfs2dc-%s",
3215                         osb->uuid_str);
3216         if (IS_ERR(osb->dc_task)) {
3217                 status = PTR_ERR(osb->dc_task);
3218                 osb->dc_task = NULL;
3219                 mlog_errno(status);
3220                 goto bail;
3221         }
3222 
3223         /* for now, uuid == domain */
3224         status = ocfs2_cluster_connect(osb->osb_cluster_stack,
3225                                        osb->osb_cluster_name,
3226                                        strlen(osb->osb_cluster_name),
3227                                        osb->uuid_str,
3228                                        strlen(osb->uuid_str),
3229                                        &lproto, ocfs2_do_node_down, osb,
3230                                        &conn);
3231         if (status) {
3232                 mlog_errno(status);
3233                 goto bail;
3234         }
3235 
3236         status = ocfs2_cluster_this_node(conn, &osb->node_num);
3237         if (status < 0) {
3238                 mlog_errno(status);
3239                 mlog(ML_ERROR,
3240                      "could not find this host's node number\n");
3241                 ocfs2_cluster_disconnect(conn, 0);
3242                 goto bail;
3243         }
3244 
3245 local:
3246         ocfs2_super_lock_res_init(&osb->osb_super_lockres, osb);
3247         ocfs2_rename_lock_res_init(&osb->osb_rename_lockres, osb);
3248         ocfs2_nfs_sync_lock_res_init(&osb->osb_nfs_sync_lockres, osb);
3249         ocfs2_orphan_scan_lock_res_init(&osb->osb_orphan_scan.os_lockres, osb);
3250 
3251         osb->cconn = conn;
3252 bail:
3253         if (status < 0) {
3254                 ocfs2_dlm_shutdown_debug(osb);
3255                 if (osb->dc_task)
3256                         kthread_stop(osb->dc_task);
3257         }
3258 
3259         return status;
3260 }
3261 
3262 void ocfs2_dlm_shutdown(struct ocfs2_super *osb,
3263                         int hangup_pending)
3264 {
3265         ocfs2_drop_osb_locks(osb);
3266 
3267         /*
3268          * Now that we have dropped all locks and ocfs2_dismount_volume()
3269          * has disabled recovery, the DLM won't be talking to us.  It's
3270          * safe to tear things down before disconnecting the cluster.
3271          */
3272 
3273         if (osb->dc_task) {
3274                 kthread_stop(osb->dc_task);
3275                 osb->dc_task = NULL;
3276         }
3277 
3278         ocfs2_lock_res_free(&osb->osb_super_lockres);
3279         ocfs2_lock_res_free(&osb->osb_rename_lockres);
3280         ocfs2_lock_res_free(&osb->osb_nfs_sync_lockres);
3281         ocfs2_lock_res_free(&osb->osb_orphan_scan.os_lockres);
3282 
3283         ocfs2_cluster_disconnect(osb->cconn, hangup_pending);
3284         osb->cconn = NULL;
3285 
3286         ocfs2_dlm_shutdown_debug(osb);
3287 }
3288 
3289 static int ocfs2_drop_lock(struct ocfs2_super *osb,
3290                            struct ocfs2_lock_res *lockres)
3291 {
3292         int ret;
3293         unsigned long flags;
3294         u32 lkm_flags = 0;
3295 
3296         /* We didn't get anywhere near actually using this lockres. */
3297         if (!(lockres->l_flags & OCFS2_LOCK_INITIALIZED))
3298                 goto out;
3299 
3300         if (lockres->l_ops->flags & LOCK_TYPE_USES_LVB)
3301                 lkm_flags |= DLM_LKF_VALBLK;
3302 
3303         spin_lock_irqsave(&lockres->l_lock, flags);
3304 
3305         mlog_bug_on_msg(!(lockres->l_flags & OCFS2_LOCK_FREEING),
3306                         "lockres %s, flags 0x%lx\n",
3307                         lockres->l_name, lockres->l_flags);
3308 
3309         while (lockres->l_flags & OCFS2_LOCK_BUSY) {
3310                 mlog(0, "waiting on busy lock \"%s\": flags = %lx, action = "
3311                      "%u, unlock_action = %u\n",
3312                      lockres->l_name, lockres->l_flags, lockres->l_action,
3313                      lockres->l_unlock_action);
3314 
3315                 spin_unlock_irqrestore(&lockres->l_lock, flags);
3316 
3317                 /* XXX: Today we just wait on any busy
3318                  * locks... Perhaps we need to cancel converts in the
3319                  * future? */
3320                 ocfs2_wait_on_busy_lock(lockres);
3321 
3322                 spin_lock_irqsave(&lockres->l_lock, flags);
3323         }
3324 
3325         if (lockres->l_ops->flags & LOCK_TYPE_USES_LVB) {
3326                 if (lockres->l_flags & OCFS2_LOCK_ATTACHED &&
3327                     lockres->l_level == DLM_LOCK_EX &&
3328                     !(lockres->l_flags & OCFS2_LOCK_NEEDS_REFRESH))
3329                         lockres->l_ops->set_lvb(lockres);
3330         }
3331 
3332         if (lockres->l_flags & OCFS2_LOCK_BUSY)
3333                 mlog(ML_ERROR, "destroying busy lock: \"%s\"\n",
3334                      lockres->l_name);
3335         if (lockres->l_flags & OCFS2_LOCK_BLOCKED)
3336                 mlog(0, "destroying blocked lock: \"%s\"\n", lockres->l_name);
3337 
3338         if (!(lockres->l_flags & OCFS2_LOCK_ATTACHED)) {
3339                 spin_unlock_irqrestore(&lockres->l_lock, flags);
3340                 goto out;
3341         }
3342 
3343         lockres_clear_flags(lockres, OCFS2_LOCK_ATTACHED);
3344 
3345         /* make sure we never get here while waiting for an ast to
3346          * fire. */
3347         BUG_ON(lockres->l_action != OCFS2_AST_INVALID);
3348 
3349         /* is this necessary? */
3350         lockres_or_flags(lockres, OCFS2_LOCK_BUSY);
3351         lockres->l_unlock_action = OCFS2_UNLOCK_DROP_LOCK;
3352         spin_unlock_irqrestore(&lockres->l_lock, flags);
3353 
3354         mlog(0, "lock %s\n", lockres->l_name);
3355 
3356         ret = ocfs2_dlm_unlock(osb->cconn, &lockres->l_lksb, lkm_flags);
3357         if (ret) {
3358                 ocfs2_log_dlm_error("ocfs2_dlm_unlock", ret, lockres);
3359                 mlog(ML_ERROR, "lockres flags: %lu\n", lockres->l_flags);
3360                 ocfs2_dlm_dump_lksb(&lockres->l_lksb);
3361                 BUG();
3362         }
3363         mlog(0, "lock %s, successful return from ocfs2_dlm_unlock\n",
3364              lockres->l_name);
3365 
3366         ocfs2_wait_on_busy_lock(lockres);
3367 out:
3368         return 0;
3369 }
3370 
3371 static void ocfs2_process_blocked_lock(struct ocfs2_super *osb,
3372                                        struct ocfs2_lock_res *lockres);
3373 
3374 /* Mark the lockres as being dropped. It will no longer be
3375  * queued if blocking, but we still may have to wait on it
3376  * being dequeued from the downconvert thread before we can consider
3377  * it safe to drop.
3378  *
3379  * You can *not* attempt to call cluster_lock on this lockres anymore. */
3380 void ocfs2_mark_lockres_freeing(struct ocfs2_super *osb,
3381                                 struct ocfs2_lock_res *lockres)
3382 {
3383         int status;
3384         struct ocfs2_mask_waiter mw;
3385         unsigned long flags, flags2;
3386 
3387         ocfs2_init_mask_waiter(&mw);
3388 
3389         spin_lock_irqsave(&lockres->l_lock, flags);
3390         lockres->l_flags |= OCFS2_LOCK_FREEING;
3391         if (lockres->l_flags & OCFS2_LOCK_QUEUED && current == osb->dc_task) {
3392                 /*
3393                  * We know the downconvert is queued but not in progress
3394                  * because we are the downconvert thread and processing
3395                  * different lock. So we can just remove the lock from the
3396                  * queue. This is not only an optimization but also a way
3397                  * to avoid the following deadlock:
3398                  *   ocfs2_dentry_post_unlock()
3399                  *     ocfs2_dentry_lock_put()
3400                  *       ocfs2_drop_dentry_lock()
3401                  *         iput()
3402                  *           ocfs2_evict_inode()
3403                  *             ocfs2_clear_inode()
3404                  *               ocfs2_mark_lockres_freeing()
3405                  *                 ... blocks waiting for OCFS2_LOCK_QUEUED
3406                  *                 since we are the downconvert thread which
3407                  *                 should clear the flag.
3408                  */
3409                 spin_unlock_irqrestore(&lockres->l_lock, flags);
3410                 spin_lock_irqsave(&osb->dc_task_lock, flags2);
3411                 list_del_init(&lockres->l_blocked_list);
3412                 osb->blocked_lock_count--;
3413                 spin_unlock_irqrestore(&osb->dc_task_lock, flags2);
3414                 /*
3415                  * Warn if we recurse into another post_unlock call.  Strictly
3416                  * speaking it isn't a problem but we need to be careful if
3417                  * that happens (stack overflow, deadlocks, ...) so warn if
3418                  * ocfs2 grows a path for which this can happen.
3419                  */
3420                 WARN_ON_ONCE(lockres->l_ops->post_unlock);
3421                 /* Since the lock is freeing we don't do much in the fn below */
3422                 ocfs2_process_blocked_lock(osb, lockres);
3423                 return;
3424         }
3425         while (lockres->l_flags & OCFS2_LOCK_QUEUED) {
3426                 lockres_add_mask_waiter(lockres, &mw, OCFS2_LOCK_QUEUED, 0);
3427                 spin_unlock_irqrestore(&lockres->l_lock, flags);
3428 
3429                 mlog(0, "Waiting on lockres %s\n", lockres->l_name);
3430 
3431                 status = ocfs2_wait_for_mask(&mw);
3432                 if (status)
3433                         mlog_errno(status);
3434 
3435                 spin_lock_irqsave(&lockres->l_lock, flags);
3436         }
3437         spin_unlock_irqrestore(&lockres->l_lock, flags);
3438 }
3439 
3440 void ocfs2_simple_drop_lockres(struct ocfs2_super *osb,
3441                                struct ocfs2_lock_res *lockres)
3442 {
3443         int ret;
3444 
3445         ocfs2_mark_lockres_freeing(osb, lockres);
3446         ret = ocfs2_drop_lock(osb, lockres);
3447         if (ret)
3448                 mlog_errno(ret);
3449 }
3450 
3451 static void ocfs2_drop_osb_locks(struct ocfs2_super *osb)
3452 {
3453         ocfs2_simple_drop_lockres(osb, &osb->osb_super_lockres);
3454         ocfs2_simple_drop_lockres(osb, &osb->osb_rename_lockres);
3455         ocfs2_simple_drop_lockres(osb, &osb->osb_nfs_sync_lockres);
3456         ocfs2_simple_drop_lockres(osb, &osb->osb_orphan_scan.os_lockres);
3457 }
3458 
3459 int ocfs2_drop_inode_locks(struct inode *inode)
3460 {
3461         int status, err;
3462 
3463         /* No need to call ocfs2_mark_lockres_freeing here -
3464          * ocfs2_clear_inode has done it for us. */
3465 
3466         err = ocfs2_drop_lock(OCFS2_SB(inode->i_sb),
3467                               &OCFS2_I(inode)->ip_open_lockres);
3468         if (err < 0)
3469                 mlog_errno(err);
3470 
3471         status = err;
3472 
3473         err = ocfs2_drop_lock(OCFS2_SB(inode->i_sb),
3474                               &OCFS2_I(inode)->ip_inode_lockres);
3475         if (err < 0)
3476                 mlog_errno(err);
3477         if (err < 0 && !status)
3478                 status = err;
3479 
3480         err = ocfs2_drop_lock(OCFS2_SB(inode->i_sb),
3481                               &OCFS2_I(inode)->ip_rw_lockres);
3482         if (err < 0)
3483                 mlog_errno(err);
3484         if (err < 0 && !status)
3485                 status = err;
3486 
3487         return status;
3488 }
3489 
3490 static unsigned int ocfs2_prepare_downconvert(struct ocfs2_lock_res *lockres,
3491                                               int new_level)
3492 {
3493         assert_spin_locked(&lockres->l_lock);
3494 
3495         BUG_ON(lockres->l_blocking <= DLM_LOCK_NL);
3496 
3497         if (lockres->l_level <= new_level) {
3498                 mlog(ML_ERROR, "lockres %s, lvl %d <= %d, blcklst %d, mask %d, "
3499                      "type %d, flags 0x%lx, hold %d %d, act %d %d, req %d, "
3500                      "block %d, pgen %d\n", lockres->l_name, lockres->l_level,
3501                      new_level, list_empty(&lockres->l_blocked_list),
3502                      list_empty(&lockres->l_mask_waiters), lockres->l_type,
3503                      lockres->l_flags, lockres->l_ro_holders,
3504                      lockres->l_ex_holders, lockres->l_action,
3505                      lockres->l_unlock_action, lockres->l_requested,
3506                      lockres->l_blocking, lockres->l_pending_gen);
3507                 BUG();
3508         }
3509 
3510         mlog(ML_BASTS, "lockres %s, level %d => %d, blocking %d\n",
3511              lockres->l_name, lockres->l_level, new_level, lockres->l_blocking);
3512 
3513         lockres->l_action = OCFS2_AST_DOWNCONVERT;
3514         lockres->l_requested = new_level;
3515         lockres_or_flags(lockres, OCFS2_LOCK_BUSY);
3516         return lockres_set_pending(lockres);
3517 }
3518 
3519 static int ocfs2_downconvert_lock(struct ocfs2_super *osb,
3520                                   struct ocfs2_lock_res *lockres,
3521                                   int new_level,
3522                                   int lvb,
3523                                   unsigned int generation)
3524 {
3525         int ret;
3526         u32 dlm_flags = DLM_LKF_CONVERT;
3527 
3528         mlog(ML_BASTS, "lockres %s, level %d => %d\n", lockres->l_name,
3529              lockres->l_level, new_level);
3530 
3531         /*
3532          * On DLM_LKF_VALBLK, fsdlm behaves differently with o2cb. It always
3533          * expects DLM_LKF_VALBLK being set if the LKB has LVB, so that
3534          * we can recover correctly from node failure. Otherwise, we may get
3535          * invalid LVB in LKB, but without DLM_SBF_VALNOTVALID being set.
3536          */
3537         if (!ocfs2_is_o2cb_active() &&
3538             lockres->l_ops->flags & LOCK_TYPE_USES_LVB)
3539                 lvb = 1;
3540 
3541         if (lvb)
3542                 dlm_flags |= DLM_LKF_VALBLK;
3543 
3544         ret = ocfs2_dlm_lock(osb->cconn,
3545                              new_level,
3546                              &lockres->l_lksb,
3547                              dlm_flags,
3548                              lockres->l_name,
3549                              OCFS2_LOCK_ID_MAX_LEN - 1);
3550         lockres_clear_pending(lockres, generation, osb);
3551         if (ret) {
3552                 ocfs2_log_dlm_error("ocfs2_dlm_lock", ret, lockres);
3553                 ocfs2_recover_from_dlm_error(lockres, 1);
3554                 goto bail;
3555         }
3556 
3557         ret = 0;
3558 bail:
3559         return ret;
3560 }
3561 
3562 /* returns 1 when the caller should unlock and call ocfs2_dlm_unlock */
3563 static int ocfs2_prepare_cancel_convert(struct ocfs2_super *osb,
3564                                         struct ocfs2_lock_res *lockres)
3565 {
3566         assert_spin_locked(&lockres->l_lock);
3567 
3568         if (lockres->l_unlock_action == OCFS2_UNLOCK_CANCEL_CONVERT) {
3569                 /* If we're already trying to cancel a lock conversion
3570                  * then just drop the spinlock and allow the caller to
3571                  * requeue this lock. */
3572                 mlog(ML_BASTS, "lockres %s, skip convert\n", lockres->l_name);
3573                 return 0;
3574         }
3575 
3576         /* were we in a convert when we got the bast fire? */
3577         BUG_ON(lockres->l_action != OCFS2_AST_CONVERT &&
3578                lockres->l_action != OCFS2_AST_DOWNCONVERT);
3579         /* set things up for the unlockast to know to just
3580          * clear out the ast_action and unset busy, etc. */
3581         lockres->l_unlock_action = OCFS2_UNLOCK_CANCEL_CONVERT;
3582 
3583         mlog_bug_on_msg(!(lockres->l_flags & OCFS2_LOCK_BUSY),
3584                         "lock %s, invalid flags: 0x%lx\n",
3585                         lockres->l_name, lockres->l_flags);
3586 
3587         mlog(ML_BASTS, "lockres %s\n", lockres->l_name);
3588 
3589         return 1;
3590 }
3591 
3592 static int ocfs2_cancel_convert(struct ocfs2_super *osb,
3593                                 struct ocfs2_lock_res *lockres)
3594 {
3595         int ret;
3596 
3597         ret = ocfs2_dlm_unlock(osb->cconn, &lockres->l_lksb,
3598                                DLM_LKF_CANCEL);
3599         if (ret) {
3600                 ocfs2_log_dlm_error("ocfs2_dlm_unlock", ret, lockres);
3601                 ocfs2_recover_from_dlm_error(lockres, 0);
3602         }
3603 
3604         mlog(ML_BASTS, "lockres %s\n", lockres->l_name);
3605 
3606         return ret;
3607 }
3608 
3609 static int ocfs2_unblock_lock(struct ocfs2_super *osb,
3610                               struct ocfs2_lock_res *lockres,
3611                               struct ocfs2_unblock_ctl *ctl)
3612 {
3613         unsigned long flags;
3614         int blocking;
3615         int new_level;
3616         int level;
3617         int ret = 0;
3618         int set_lvb = 0;
3619         unsigned int gen;
3620 
3621         spin_lock_irqsave(&lockres->l_lock, flags);
3622 
3623 recheck:
3624         /*
3625          * Is it still blocking? If not, we have no more work to do.
3626          */
3627         if (!(lockres->l_flags & OCFS2_LOCK_BLOCKED)) {
3628                 BUG_ON(lockres->l_blocking != DLM_LOCK_NL);
3629                 spin_unlock_irqrestore(&lockres->l_lock, flags);
3630                 ret = 0;
3631                 goto leave;
3632         }
3633 
3634         if (lockres->l_flags & OCFS2_LOCK_BUSY) {
3635                 /* XXX
3636                  * This is a *big* race.  The OCFS2_LOCK_PENDING flag
3637                  * exists entirely for one reason - another thread has set
3638                  * OCFS2_LOCK_BUSY, but has *NOT* yet called dlm_lock().
3639                  *
3640                  * If we do ocfs2_cancel_convert() before the other thread
3641                  * calls dlm_lock(), our cancel will do nothing.  We will
3642                  * get no ast, and we will have no way of knowing the
3643                  * cancel failed.  Meanwhile, the other thread will call
3644                  * into dlm_lock() and wait...forever.
3645                  *
3646                  * Why forever?  Because another node has asked for the
3647                  * lock first; that's why we're here in unblock_lock().
3648                  *
3649                  * The solution is OCFS2_LOCK_PENDING.  When PENDING is
3650                  * set, we just requeue the unblock.  Only when the other
3651                  * thread has called dlm_lock() and cleared PENDING will
3652                  * we then cancel their request.
3653                  *
3654                  * All callers of dlm_lock() must set OCFS2_DLM_PENDING
3655                  * at the same time they set OCFS2_DLM_BUSY.  They must
3656                  * clear OCFS2_DLM_PENDING after dlm_lock() returns.
3657                  */
3658                 if (lockres->l_flags & OCFS2_LOCK_PENDING) {
3659                         mlog(ML_BASTS, "lockres %s, ReQ: Pending\n",
3660                              lockres->l_name);
3661                         goto leave_requeue;
3662                 }
3663 
3664                 ctl->requeue = 1;
3665                 ret = ocfs2_prepare_cancel_convert(osb, lockres);
3666                 spin_unlock_irqrestore(&lockres->l_lock, flags);
3667                 if (ret) {
3668                         ret = ocfs2_cancel_convert(osb, lockres);
3669                         if (ret < 0)
3670                                 mlog_errno(ret);
3671                 }
3672                 goto leave;
3673         }
3674 
3675         /*
3676          * This prevents livelocks. OCFS2_LOCK_UPCONVERT_FINISHING flag is
3677          * set when the ast is received for an upconvert just before the
3678          * OCFS2_LOCK_BUSY flag is cleared. Now if the fs received a bast
3679          * on the heels of the ast, we want to delay the downconvert just
3680          * enough to allow the up requestor to do its task. Because this
3681          * lock is in the blocked queue, the lock will be downconverted
3682          * as soon as the requestor is done with the lock.
3683          */
3684         if (lockres->l_flags & OCFS2_LOCK_UPCONVERT_FINISHING)
3685                 goto leave_requeue;
3686 
3687         /*
3688          * How can we block and yet be at NL?  We were trying to upconvert
3689          * from NL and got canceled.  The code comes back here, and now
3690          * we notice and clear BLOCKING.
3691          */
3692         if (lockres->l_level == DLM_LOCK_NL) {
3693                 BUG_ON(lockres->l_ex_holders || lockres->l_ro_holders);
3694                 mlog(ML_BASTS, "lockres %s, Aborting dc\n", lockres->l_name);
3695                 lockres->l_blocking = DLM_LOCK_NL;
3696                 lockres_clear_flags(lockres, OCFS2_LOCK_BLOCKED);
3697                 spin_unlock_irqrestore(&lockres->l_lock, flags);
3698                 goto leave;
3699         }
3700 
3701         /* if we're blocking an exclusive and we have *any* holders,
3702          * then requeue. */
3703         if ((lockres->l_blocking == DLM_LOCK_EX)
3704             && (lockres->l_ex_holders || lockres->l_ro_holders)) {
3705                 mlog(ML_BASTS, "lockres %s, ReQ: EX/PR Holders %u,%u\n",
3706                      lockres->l_name, lockres->l_ex_holders,
3707                      lockres->l_ro_holders);
3708                 goto leave_requeue;
3709         }
3710 
3711         /* If it's a PR we're blocking, then only
3712          * requeue if we've got any EX holders */
3713         if (lockres->l_blocking == DLM_LOCK_PR &&
3714             lockres->l_ex_holders) {
3715                 mlog(ML_BASTS, "lockres %s, ReQ: EX Holders %u\n",
3716                      lockres->l_name, lockres->l_ex_holders);
3717                 goto leave_requeue;
3718         }
3719 
3720         /*
3721          * Can we get a lock in this state if the holder counts are
3722          * zero? The meta data unblock code used to check this.
3723          */
3724         if ((lockres->l_ops->flags & LOCK_TYPE_REQUIRES_REFRESH)
3725             && (lockres->l_flags & OCFS2_LOCK_REFRESHING)) {
3726                 mlog(ML_BASTS, "lockres %s, ReQ: Lock Refreshing\n",
3727                      lockres->l_name);
3728                 goto leave_requeue;
3729         }
3730 
3731         new_level = ocfs2_highest_compat_lock_level(lockres->l_blocking);
3732 
3733         if (lockres->l_ops->check_downconvert
3734             && !lockres->l_ops->check_downconvert(lockres, new_level)) {
3735                 mlog(ML_BASTS, "lockres %s, ReQ: Checkpointing\n",
3736                      lockres->l_name);
3737                 goto leave_requeue;
3738         }
3739 
3740         /* If we get here, then we know that there are no more
3741          * incompatible holders (and anyone asking for an incompatible
3742          * lock is blocked). We can now downconvert the lock */
3743         if (!lockres->l_ops->downconvert_worker)
3744                 goto downconvert;
3745 
3746         /* Some lockres types want to do a bit of work before
3747          * downconverting a lock. Allow that here. The worker function
3748          * may sleep, so we save off a copy of what we're blocking as
3749          * it may change while we're not holding the spin lock. */
3750         blocking = lockres->l_blocking;
3751         level = lockres->l_level;
3752         spin_unlock_irqrestore(&lockres->l_lock, flags);
3753 
3754         ctl->unblock_action = lockres->l_ops->downconvert_worker(lockres, blocking);
3755 
3756         if (ctl->unblock_action == UNBLOCK_STOP_POST) {
3757                 mlog(ML_BASTS, "lockres %s, UNBLOCK_STOP_POST\n",
3758                      lockres->l_name);
3759                 goto leave;
3760         }
3761 
3762         spin_lock_irqsave(&lockres->l_lock, flags);
3763         if ((blocking != lockres->l_blocking) || (level != lockres->l_level)) {
3764                 /* If this changed underneath us, then we can't drop
3765                  * it just yet. */
3766                 mlog(ML_BASTS, "lockres %s, block=%d:%d, level=%d:%d, "
3767                      "Recheck\n", lockres->l_name, blocking,
3768                      lockres->l_blocking, level, lockres->l_level);
3769                 goto recheck;
3770         }
3771 
3772 downconvert:
3773         ctl->requeue = 0;
3774 
3775         if (lockres->l_ops->flags & LOCK_TYPE_USES_LVB) {
3776                 if (lockres->l_level == DLM_LOCK_EX)
3777                         set_lvb = 1;
3778 
3779                 /*
3780                  * We only set the lvb if the lock has been fully
3781                  * refreshed - otherwise we risk setting stale
3782                  * data. Otherwise, there's no need to actually clear
3783                  * out the lvb here as it's value is still valid.
3784                  */
3785                 if (set_lvb && !(lockres->l_flags & OCFS2_LOCK_NEEDS_REFRESH))
3786                         lockres->l_ops->set_lvb(lockres);
3787         }
3788 
3789         gen = ocfs2_prepare_downconvert(lockres, new_level);
3790         spin_unlock_irqrestore(&lockres->l_lock, flags);
3791         ret = ocfs2_downconvert_lock(osb, lockres, new_level, set_lvb,
3792                                      gen);
3793 
3794 leave:
3795         if (ret)
3796                 mlog_errno(ret);
3797         return ret;
3798 
3799 leave_requeue:
3800         spin_unlock_irqrestore(&lockres->l_lock, flags);
3801         ctl->requeue = 1;
3802 
3803         return 0;
3804 }
3805 
3806 static int ocfs2_data_convert_worker(struct ocfs2_lock_res *lockres,
3807                                      int blocking)
3808 {
3809         struct inode *inode;
3810         struct address_space *mapping;
3811         struct ocfs2_inode_info *oi;
3812 
3813         inode = ocfs2_lock_res_inode(lockres);
3814         mapping = inode->i_mapping;
3815 
3816         if (S_ISDIR(inode->i_mode)) {
3817                 oi = OCFS2_I(inode);
3818                 oi->ip_dir_lock_gen++;
3819                 mlog(0, "generation: %u\n", oi->ip_dir_lock_gen);
3820                 goto out;
3821         }
3822 
3823         if (!S_ISREG(inode->i_mode))
3824                 goto out;
3825 
3826         /*
3827          * We need this before the filemap_fdatawrite() so that it can
3828          * transfer the dirty bit from the PTE to the
3829          * page. Unfortunately this means that even for EX->PR
3830          * downconverts, we'll lose our mappings and have to build
3831          * them up again.
3832          */
3833         unmap_mapping_range(mapping, 0, 0, 0);
3834 
3835         if (filemap_fdatawrite(mapping)) {
3836                 mlog(ML_ERROR, "Could not sync inode %llu for downconvert!",
3837                      (unsigned long long)OCFS2_I(inode)->ip_blkno);
3838         }
3839         sync_mapping_buffers(mapping);
3840         if (blocking == DLM_LOCK_EX) {
3841                 truncate_inode_pages(mapping, 0);
3842         } else {
3843                 /* We only need to wait on the I/O if we're not also
3844                  * truncating pages because truncate_inode_pages waits
3845                  * for us above. We don't truncate pages if we're
3846                  * blocking anything < EXMODE because we want to keep
3847                  * them around in that case. */
3848                 filemap_fdatawait(mapping);
3849         }
3850 
3851         forget_all_cached_acls(inode);
3852 
3853 out:
3854         return UNBLOCK_CONTINUE;
3855 }
3856 
3857 static int ocfs2_ci_checkpointed(struct ocfs2_caching_info *ci,
3858                                  struct ocfs2_lock_res *lockres,
3859                                  int new_level)
3860 {
3861         int checkpointed = ocfs2_ci_fully_checkpointed(ci);
3862 
3863         BUG_ON(new_level != DLM_LOCK_NL && new_level != DLM_LOCK_PR);
3864         BUG_ON(lockres->l_level != DLM_LOCK_EX && !checkpointed);
3865 
3866         if (checkpointed)
3867                 return 1;
3868 
3869         ocfs2_start_checkpoint(OCFS2_SB(ocfs2_metadata_cache_get_super(ci)));
3870         return 0;
3871 }
3872 
3873 static int ocfs2_check_meta_downconvert(struct ocfs2_lock_res *lockres,
3874                                         int new_level)
3875 {
3876         struct inode *inode = ocfs2_lock_res_inode(lockres);
3877 
3878         return ocfs2_ci_checkpointed(INODE_CACHE(inode), lockres, new_level);
3879 }
3880 
3881 static void ocfs2_set_meta_lvb(struct ocfs2_lock_res *lockres)
3882 {
3883         struct inode *inode = ocfs2_lock_res_inode(lockres);
3884 
3885         __ocfs2_stuff_meta_lvb(inode);
3886 }
3887 
3888 /*
3889  * Does the final reference drop on our dentry lock. Right now this
3890  * happens in the downconvert thread, but we could choose to simplify the
3891  * dlmglue API and push these off to the ocfs2_wq in the future.
3892  */
3893 static void ocfs2_dentry_post_unlock(struct ocfs2_super *osb,
3894                                      struct ocfs2_lock_res *lockres)
3895 {
3896         struct ocfs2_dentry_lock *dl = ocfs2_lock_res_dl(lockres);
3897         ocfs2_dentry_lock_put(osb, dl);
3898 }
3899 
3900 /*
3901  * d_delete() matching dentries before the lock downconvert.
3902  *
3903  * At this point, any process waiting to destroy the
3904  * dentry_lock due to last ref count is stopped by the
3905  * OCFS2_LOCK_QUEUED flag.
3906  *
3907  * We have two potential problems
3908  *
3909  * 1) If we do the last reference drop on our dentry_lock (via dput)
3910  *    we'll wind up in ocfs2_release_dentry_lock(), waiting on
3911  *    the downconvert to finish. Instead we take an elevated
3912  *    reference and push the drop until after we've completed our
3913  *    unblock processing.
3914  *
3915  * 2) There might be another process with a final reference,
3916  *    waiting on us to finish processing. If this is the case, we
3917  *    detect it and exit out - there's no more dentries anyway.
3918  */
3919 static int ocfs2_dentry_convert_worker(struct ocfs2_lock_res *lockres,
3920                                        int blocking)
3921 {
3922         struct ocfs2_dentry_lock *dl = ocfs2_lock_res_dl(lockres);
3923         struct ocfs2_inode_info *oi = OCFS2_I(dl->dl_inode);
3924         struct dentry *dentry;
3925         unsigned long flags;
3926         int extra_ref = 0;
3927 
3928         /*
3929          * This node is blocking another node from getting a read
3930          * lock. This happens when we've renamed within a
3931          * directory. We've forced the other nodes to d_delete(), but
3932          * we never actually dropped our lock because it's still
3933          * valid. The downconvert code will retain a PR for this node,
3934          * so there's no further work to do.
3935          */
3936         if (blocking == DLM_LOCK_PR)
3937                 return UNBLOCK_CONTINUE;
3938 
3939         /*
3940          * Mark this inode as potentially orphaned. The code in
3941          * ocfs2_delete_inode() will figure out whether it actually
3942          * needs to be freed or not.
3943          */
3944         spin_lock(&oi->ip_lock);
3945         oi->ip_flags |= OCFS2_INODE_MAYBE_ORPHANED;
3946         spin_unlock(&oi->ip_lock);
3947 
3948         /*
3949          * Yuck. We need to make sure however that the check of
3950          * OCFS2_LOCK_FREEING and the extra reference are atomic with
3951          * respect to a reference decrement or the setting of that
3952          * flag.
3953          */
3954         spin_lock_irqsave(&lockres->l_lock, flags);
3955         spin_lock(&dentry_attach_lock);
3956         if (!(lockres->l_flags & OCFS2_LOCK_FREEING)
3957             && dl->dl_count) {
3958                 dl->dl_count++;
3959                 extra_ref = 1;
3960         }
3961         spin_unlock(&dentry_attach_lock);
3962         spin_unlock_irqrestore(&lockres->l_lock, flags);
3963 
3964         mlog(0, "extra_ref = %d\n", extra_ref);
3965 
3966         /*
3967          * We have a process waiting on us in ocfs2_dentry_iput(),
3968          * which means we can't have any more outstanding
3969          * aliases. There's no need to do any more work.
3970          */
3971         if (!extra_ref)
3972                 return UNBLOCK_CONTINUE;
3973 
3974         spin_lock(&dentry_attach_lock);
3975         while (1) {
3976                 dentry = ocfs2_find_local_alias(dl->dl_inode,
3977                                                 dl->dl_parent_blkno, 1);
3978                 if (!dentry)
3979                         break;
3980                 spin_unlock(&dentry_attach_lock);
3981 
3982                 if (S_ISDIR(dl->dl_inode->i_mode))
3983                         shrink_dcache_parent(dentry);
3984 
3985                 mlog(0, "d_delete(%pd);\n", dentry);
3986 
3987                 /*
3988                  * The following dcache calls may do an
3989                  * iput(). Normally we don't want that from the
3990                  * downconverting thread, but in this case it's ok
3991                  * because the requesting node already has an
3992                  * exclusive lock on the inode, so it can't be queued
3993                  * for a downconvert.
3994                  */
3995                 d_delete(dentry);
3996                 dput(dentry);
3997 
3998                 spin_lock(&dentry_attach_lock);
3999         }
4000         spin_unlock(&dentry_attach_lock);
4001 
4002         /*
4003          * If we are the last holder of this dentry lock, there is no
4004          * reason to downconvert so skip straight to the unlock.
4005          */
4006         if (dl->dl_count == 1)
4007                 return UNBLOCK_STOP_POST;
4008 
4009         return UNBLOCK_CONTINUE_POST;
4010 }
4011 
4012 static int ocfs2_check_refcount_downconvert(struct ocfs2_lock_res *lockres,
4013                                             int new_level)
4014 {
4015         struct ocfs2_refcount_tree *tree =
4016                                 ocfs2_lock_res_refcount_tree(lockres);
4017 
4018         return ocfs2_ci_checkpointed(&tree->rf_ci, lockres, new_level);
4019 }
4020 
4021 static int ocfs2_refcount_convert_worker(struct ocfs2_lock_res *lockres,
4022                                          int blocking)
4023 {
4024         struct ocfs2_refcount_tree *tree =
4025                                 ocfs2_lock_res_refcount_tree(lockres);
4026 
4027         ocfs2_metadata_cache_purge(&tree->rf_ci);
4028 
4029         return UNBLOCK_CONTINUE;
4030 }
4031 
4032 static void ocfs2_set_qinfo_lvb(struct ocfs2_lock_res *lockres)
4033 {
4034         struct ocfs2_qinfo_lvb *lvb;
4035         struct ocfs2_mem_dqinfo *oinfo = ocfs2_lock_res_qinfo(lockres);
4036         struct mem_dqinfo *info = sb_dqinfo(oinfo->dqi_gi.dqi_sb,
4037                                             oinfo->dqi_gi.dqi_type);
4038 
4039         lvb = ocfs2_dlm_lvb(&lockres->l_lksb);
4040         lvb->lvb_version = OCFS2_QINFO_LVB_VERSION;
4041         lvb->lvb_bgrace = cpu_to_be32(info->dqi_bgrace);
4042         lvb->lvb_igrace = cpu_to_be32(info->dqi_igrace);
4043         lvb->lvb_syncms = cpu_to_be32(oinfo->dqi_syncms);
4044         lvb->lvb_blocks = cpu_to_be32(oinfo->dqi_gi.dqi_blocks);
4045         lvb->lvb_free_blk = cpu_to_be32(oinfo->dqi_gi.dqi_free_blk);
4046         lvb->lvb_free_entry = cpu_to_be32(oinfo->dqi_gi.dqi_free_entry);
4047 }
4048 
4049 void ocfs2_qinfo_unlock(struct ocfs2_mem_dqinfo *oinfo, int ex)
4050 {
4051         struct ocfs2_lock_res *lockres = &oinfo->dqi_gqlock;
4052         struct ocfs2_super *osb = OCFS2_SB(oinfo->dqi_gi.dqi_sb);
4053         int level = ex ? DLM_LOCK_EX : DLM_LOCK_PR;
4054 
4055         if (!ocfs2_is_hard_readonly(osb) && !ocfs2_mount_local(osb))
4056                 ocfs2_cluster_unlock(osb, lockres, level);
4057 }
4058 
4059 static int ocfs2_refresh_qinfo(struct ocfs2_mem_dqinfo *oinfo)
4060 {
4061         struct mem_dqinfo *info = sb_dqinfo(oinfo->dqi_gi.dqi_sb,
4062                                             oinfo->dqi_gi.dqi_type);
4063         struct ocfs2_lock_res *lockres = &oinfo->dqi_gqlock;
4064         struct ocfs2_qinfo_lvb *lvb = ocfs2_dlm_lvb(&lockres->l_lksb);
4065         struct buffer_head *bh = NULL;
4066         struct ocfs2_global_disk_dqinfo *gdinfo;
4067         int status = 0;
4068 
4069         if (ocfs2_dlm_lvb_valid(&lockres->l_lksb) &&
4070             lvb->lvb_version == OCFS2_QINFO_LVB_VERSION) {
4071                 info->dqi_bgrace = be32_to_cpu(lvb->lvb_bgrace);
4072                 info->dqi_igrace = be32_to_cpu(lvb->lvb_igrace);
4073                 oinfo->dqi_syncms = be32_to_cpu(lvb->lvb_syncms);
4074                 oinfo->dqi_gi.dqi_blocks = be32_to_cpu(lvb->lvb_blocks);
4075                 oinfo->dqi_gi.dqi_free_blk = be32_to_cpu(lvb->lvb_free_blk);
4076                 oinfo->dqi_gi.dqi_free_entry =
4077                                         be32_to_cpu(lvb->lvb_free_entry);
4078         } else {
4079                 status = ocfs2_read_quota_phys_block(oinfo->dqi_gqinode,
4080                                                      oinfo->dqi_giblk, &bh);
4081                 if (status) {
4082                         mlog_errno(status);
4083                         goto bail;
4084                 }
4085                 gdinfo = (struct ocfs2_global_disk_dqinfo *)
4086                                         (bh->b_data + OCFS2_GLOBAL_INFO_OFF);
4087                 info->dqi_bgrace = le32_to_cpu(gdinfo->dqi_bgrace);
4088                 info->dqi_igrace = le32_to_cpu(gdinfo->dqi_igrace);
4089                 oinfo->dqi_syncms = le32_to_cpu(gdinfo->dqi_syncms);
4090                 oinfo->dqi_gi.dqi_blocks = le32_to_cpu(gdinfo->dqi_blocks);
4091                 oinfo->dqi_gi.dqi_free_blk = le32_to_cpu(gdinfo->dqi_free_blk);
4092                 oinfo->dqi_gi.dqi_free_entry =
4093                                         le32_to_cpu(gdinfo->dqi_free_entry);
4094                 brelse(bh);
4095                 ocfs2_track_lock_refresh(lockres);
4096         }
4097 
4098 bail:
4099         return status;
4100 }
4101 
4102 /* Lock quota info, this function expects at least shared lock on the quota file
4103  * so that we can safely refresh quota info from disk. */
4104 int ocfs2_qinfo_lock(struct ocfs2_mem_dqinfo *oinfo, int ex)
4105 {
4106         struct ocfs2_lock_res *lockres = &oinfo->dqi_gqlock;
4107         struct ocfs2_super *osb = OCFS2_SB(oinfo->dqi_gi.dqi_sb);
4108         int level = ex ? DLM_LOCK_EX : DLM_LOCK_PR;
4109         int status = 0;
4110 
4111         /* On RO devices, locking really isn't needed... */
4112         if (ocfs2_is_hard_readonly(osb)) {
4113                 if (ex)
4114                         status = -EROFS;
4115                 goto bail;
4116         }
4117         if (ocfs2_mount_local(osb))
4118                 goto bail;
4119 
4120         status = ocfs2_cluster_lock(osb, lockres, level, 0, 0);
4121         if (status < 0) {
4122                 mlog_errno(status);
4123                 goto bail;
4124         }
4125         if (!ocfs2_should_refresh_lock_res(lockres))
4126                 goto bail;
4127         /* OK, we have the lock but we need to refresh the quota info */
4128         status = ocfs2_refresh_qinfo(oinfo);
4129         if (status)
4130                 ocfs2_qinfo_unlock(oinfo, ex);
4131         ocfs2_complete_lock_res_refresh(lockres, status);
4132 bail:
4133         return status;
4134 }
4135 
4136 int ocfs2_refcount_lock(struct ocfs2_refcount_tree *ref_tree, int ex)
4137 {
4138         int status;
4139         int level = ex ? DLM_LOCK_EX : DLM_LOCK_PR;
4140         struct ocfs2_lock_res *lockres = &ref_tree->rf_lockres;
4141         struct ocfs2_super *osb = lockres->l_priv;
4142 
4143 
4144         if (ocfs2_is_hard_readonly(osb))
4145                 return -EROFS;
4146 
4147         if (ocfs2_mount_local(osb))
4148                 return 0;
4149 
4150         status = ocfs2_cluster_lock(osb, lockres, level, 0, 0);
4151         if (status < 0)
4152                 mlog_errno(status);
4153 
4154         return status;
4155 }
4156 
4157 void ocfs2_refcount_unlock(struct ocfs2_refcount_tree *ref_tree, int ex)
4158 {
4159         int level = ex ? DLM_LOCK_EX : DLM_LOCK_PR;
4160         struct ocfs2_lock_res *lockres = &ref_tree->rf_lockres;
4161         struct ocfs2_super *osb = lockres->l_priv;
4162 
4163         if (!ocfs2_mount_local(osb))
4164                 ocfs2_cluster_unlock(osb, lockres, level);
4165 }
4166 
4167 static void ocfs2_process_blocked_lock(struct ocfs2_super *osb,
4168                                        struct ocfs2_lock_res *lockres)
4169 {
4170         int status;
4171         struct ocfs2_unblock_ctl ctl = {0, 0,};
4172         unsigned long flags;
4173 
4174         /* Our reference to the lockres in this function can be
4175          * considered valid until we remove the OCFS2_LOCK_QUEUED
4176          * flag. */
4177 
4178         BUG_ON(!lockres);
4179         BUG_ON(!lockres->l_ops);
4180 
4181         mlog(ML_BASTS, "lockres %s blocked\n", lockres->l_name);
4182 
4183         /* Detect whether a lock has been marked as going away while
4184          * the downconvert thread was processing other things. A lock can
4185          * still be marked with OCFS2_LOCK_FREEING after this check,
4186          * but short circuiting here will still save us some
4187          * performance. */
4188         spin_lock_irqsave(&lockres->l_lock, flags);
4189         if (lockres->l_flags & OCFS2_LOCK_FREEING)
4190                 goto unqueue;
4191         spin_unlock_irqrestore(&lockres->l_lock, flags);
4192 
4193         status = ocfs2_unblock_lock(osb, lockres, &ctl);
4194         if (status < 0)
4195                 mlog_errno(status);
4196 
4197         spin_lock_irqsave(&lockres->l_lock, flags);
4198 unqueue:
4199         if (lockres->l_flags & OCFS2_LOCK_FREEING || !ctl.requeue) {
4200                 lockres_clear_flags(lockres, OCFS2_LOCK_QUEUED);
4201         } else
4202                 ocfs2_schedule_blocked_lock(osb, lockres);
4203 
4204         mlog(ML_BASTS, "lockres %s, requeue = %s.\n", lockres->l_name,
4205              ctl.requeue ? "yes" : "no");
4206         spin_unlock_irqrestore(&lockres->l_lock, flags);
4207 
4208         if (ctl.unblock_action != UNBLOCK_CONTINUE
4209             && lockres->l_ops->post_unlock)
4210                 lockres->l_ops->post_unlock(osb, lockres);
4211 }
4212 
4213 static void ocfs2_schedule_blocked_lock(struct ocfs2_super *osb,
4214                                         struct ocfs2_lock_res *lockres)
4215 {
4216         unsigned long flags;
4217 
4218         assert_spin_locked(&lockres->l_lock);
4219 
4220         if (lockres->l_flags & OCFS2_LOCK_FREEING) {
4221                 /* Do not schedule a lock for downconvert when it's on
4222                  * the way to destruction - any nodes wanting access
4223                  * to the resource will get it soon. */
4224                 mlog(ML_BASTS, "lockres %s won't be scheduled: flags 0x%lx\n",
4225                      lockres->l_name, lockres->l_flags);
4226                 return;
4227         }
4228 
4229         lockres_or_flags(lockres, OCFS2_LOCK_QUEUED);
4230 
4231         spin_lock_irqsave(&osb->dc_task_lock, flags);
4232         if (list_empty(&lockres->l_blocked_list)) {
4233                 list_add_tail(&lockres->l_blocked_list,
4234                               &osb->blocked_lock_list);
4235                 osb->blocked_lock_count++;
4236         }
4237         spin_unlock_irqrestore(&osb->dc_task_lock, flags);
4238 }
4239 
4240 static void ocfs2_downconvert_thread_do_work(struct ocfs2_super *osb)
4241 {
4242         unsigned long processed;
4243         unsigned long flags;
4244         struct ocfs2_lock_res *lockres;
4245 
4246         spin_lock_irqsave(&osb->dc_task_lock, flags);
4247         /* grab this early so we know to try again if a state change and
4248          * wake happens part-way through our work  */
4249         osb->dc_work_sequence = osb->dc_wake_sequence;
4250 
4251         processed = osb->blocked_lock_count;
4252         /*
4253          * blocked lock processing in this loop might call iput which can
4254          * remove items off osb->blocked_lock_list. Downconvert up to
4255          * 'processed' number of locks, but stop short if we had some
4256          * removed in ocfs2_mark_lockres_freeing when downconverting.
4257          */
4258         while (processed && !list_empty(&osb->blocked_lock_list)) {
4259                 lockres = list_entry(osb->blocked_lock_list.next,
4260                                      struct ocfs2_lock_res, l_blocked_list);
4261                 list_del_init(&lockres->l_blocked_list);
4262                 osb->blocked_lock_count--;
4263                 spin_unlock_irqrestore(&osb->dc_task_lock, flags);
4264 
4265                 BUG_ON(!processed);
4266                 processed--;
4267 
4268                 ocfs2_process_blocked_lock(osb, lockres);
4269 
4270                 spin_lock_irqsave(&osb->dc_task_lock, flags);
4271         }
4272         spin_unlock_irqrestore(&osb->dc_task_lock, flags);
4273 }
4274 
4275 static int ocfs2_downconvert_thread_lists_empty(struct ocfs2_super *osb)
4276 {
4277         int empty = 0;
4278         unsigned long flags;
4279 
4280         spin_lock_irqsave(&osb->dc_task_lock, flags);
4281         if (list_empty(&osb->blocked_lock_list))
4282                 empty = 1;
4283 
4284         spin_unlock_irqrestore(&osb->dc_task_lock, flags);
4285         return empty;
4286 }
4287 
4288 static int ocfs2_downconvert_thread_should_wake(struct ocfs2_super *osb)
4289 {
4290         int should_wake = 0;
4291         unsigned long flags;
4292 
4293         spin_lock_irqsave(&osb->dc_task_lock, flags);
4294         if (osb->dc_work_sequence != osb->dc_wake_sequence)
4295                 should_wake = 1;
4296         spin_unlock_irqrestore(&osb->dc_task_lock, flags);
4297 
4298         return should_wake;
4299 }
4300 
4301 static int ocfs2_downconvert_thread(void *arg)
4302 {
4303         int status = 0;
4304         struct ocfs2_super *osb = arg;
4305 
4306         /* only quit once we've been asked to stop and there is no more
4307          * work available */
4308         while (!(kthread_should_stop() &&
4309                 ocfs2_downconvert_thread_lists_empty(osb))) {
4310 
4311                 wait_event_interruptible(osb->dc_event,
4312                                          ocfs2_downconvert_thread_should_wake(osb) ||
4313                                          kthread_should_stop());
4314 
4315                 mlog(0, "downconvert_thread: awoken\n");
4316 
4317                 ocfs2_downconvert_thread_do_work(osb);
4318         }
4319 
4320         osb->dc_task = NULL;
4321         return status;
4322 }
4323 
4324 void ocfs2_wake_downconvert_thread(struct ocfs2_super *osb)
4325 {
4326         unsigned long flags;
4327 
4328         spin_lock_irqsave(&osb->dc_task_lock, flags);
4329         /* make sure the voting thread gets a swipe at whatever changes
4330          * the caller may have made to the voting state */
4331         osb->dc_wake_sequence++;
4332         spin_unlock_irqrestore(&osb->dc_task_lock, flags);
4333         wake_up(&osb->dc_event);
4334 }
4335 

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