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TOMOYO Linux Cross Reference
Linux/fs/ceph/caps.c

Version: ~ [ linux-5.0-rc6 ] ~ [ linux-4.20.10 ] ~ [ linux-4.19.23 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.101 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.158 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.174 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.134 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.63 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-3.9.11 ] ~ [ linux-3.8.13 ] ~ [ linux-3.7.10 ] ~ [ linux-3.6.11 ] ~ [ linux-3.5.7 ] ~ [ linux-3.4.113 ] ~ [ linux-3.3.8 ] ~ [ linux-3.2.102 ] ~ [ linux-3.1.10 ] ~ [ linux-3.0.101 ] ~ [ linux-2.6.39.4 ] ~ [ linux-2.6.38.8 ] ~ [ linux-2.6.37.6 ] ~ [ linux-2.6.36.4 ] ~ [ linux-2.6.35.14 ] ~ [ linux-2.6.34.15 ] ~ [ linux-2.6.33.20 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  1 // SPDX-License-Identifier: GPL-2.0
  2 #include <linux/ceph/ceph_debug.h>
  3 
  4 #include <linux/fs.h>
  5 #include <linux/kernel.h>
  6 #include <linux/sched/signal.h>
  7 #include <linux/slab.h>
  8 #include <linux/vmalloc.h>
  9 #include <linux/wait.h>
 10 #include <linux/writeback.h>
 11 
 12 #include "super.h"
 13 #include "mds_client.h"
 14 #include "cache.h"
 15 #include <linux/ceph/decode.h>
 16 #include <linux/ceph/messenger.h>
 17 
 18 /*
 19  * Capability management
 20  *
 21  * The Ceph metadata servers control client access to inode metadata
 22  * and file data by issuing capabilities, granting clients permission
 23  * to read and/or write both inode field and file data to OSDs
 24  * (storage nodes).  Each capability consists of a set of bits
 25  * indicating which operations are allowed.
 26  *
 27  * If the client holds a *_SHARED cap, the client has a coherent value
 28  * that can be safely read from the cached inode.
 29  *
 30  * In the case of a *_EXCL (exclusive) or FILE_WR capabilities, the
 31  * client is allowed to change inode attributes (e.g., file size,
 32  * mtime), note its dirty state in the ceph_cap, and asynchronously
 33  * flush that metadata change to the MDS.
 34  *
 35  * In the event of a conflicting operation (perhaps by another
 36  * client), the MDS will revoke the conflicting client capabilities.
 37  *
 38  * In order for a client to cache an inode, it must hold a capability
 39  * with at least one MDS server.  When inodes are released, release
 40  * notifications are batched and periodically sent en masse to the MDS
 41  * cluster to release server state.
 42  */
 43 
 44 static u64 __get_oldest_flush_tid(struct ceph_mds_client *mdsc);
 45 static void __kick_flushing_caps(struct ceph_mds_client *mdsc,
 46                                  struct ceph_mds_session *session,
 47                                  struct ceph_inode_info *ci,
 48                                  u64 oldest_flush_tid);
 49 
 50 /*
 51  * Generate readable cap strings for debugging output.
 52  */
 53 #define MAX_CAP_STR 20
 54 static char cap_str[MAX_CAP_STR][40];
 55 static DEFINE_SPINLOCK(cap_str_lock);
 56 static int last_cap_str;
 57 
 58 static char *gcap_string(char *s, int c)
 59 {
 60         if (c & CEPH_CAP_GSHARED)
 61                 *s++ = 's';
 62         if (c & CEPH_CAP_GEXCL)
 63                 *s++ = 'x';
 64         if (c & CEPH_CAP_GCACHE)
 65                 *s++ = 'c';
 66         if (c & CEPH_CAP_GRD)
 67                 *s++ = 'r';
 68         if (c & CEPH_CAP_GWR)
 69                 *s++ = 'w';
 70         if (c & CEPH_CAP_GBUFFER)
 71                 *s++ = 'b';
 72         if (c & CEPH_CAP_GWREXTEND)
 73                 *s++ = 'a';
 74         if (c & CEPH_CAP_GLAZYIO)
 75                 *s++ = 'l';
 76         return s;
 77 }
 78 
 79 const char *ceph_cap_string(int caps)
 80 {
 81         int i;
 82         char *s;
 83         int c;
 84 
 85         spin_lock(&cap_str_lock);
 86         i = last_cap_str++;
 87         if (last_cap_str == MAX_CAP_STR)
 88                 last_cap_str = 0;
 89         spin_unlock(&cap_str_lock);
 90 
 91         s = cap_str[i];
 92 
 93         if (caps & CEPH_CAP_PIN)
 94                 *s++ = 'p';
 95 
 96         c = (caps >> CEPH_CAP_SAUTH) & 3;
 97         if (c) {
 98                 *s++ = 'A';
 99                 s = gcap_string(s, c);
100         }
101 
102         c = (caps >> CEPH_CAP_SLINK) & 3;
103         if (c) {
104                 *s++ = 'L';
105                 s = gcap_string(s, c);
106         }
107 
108         c = (caps >> CEPH_CAP_SXATTR) & 3;
109         if (c) {
110                 *s++ = 'X';
111                 s = gcap_string(s, c);
112         }
113 
114         c = caps >> CEPH_CAP_SFILE;
115         if (c) {
116                 *s++ = 'F';
117                 s = gcap_string(s, c);
118         }
119 
120         if (s == cap_str[i])
121                 *s++ = '-';
122         *s = 0;
123         return cap_str[i];
124 }
125 
126 void ceph_caps_init(struct ceph_mds_client *mdsc)
127 {
128         INIT_LIST_HEAD(&mdsc->caps_list);
129         spin_lock_init(&mdsc->caps_list_lock);
130 }
131 
132 void ceph_caps_finalize(struct ceph_mds_client *mdsc)
133 {
134         struct ceph_cap *cap;
135 
136         spin_lock(&mdsc->caps_list_lock);
137         while (!list_empty(&mdsc->caps_list)) {
138                 cap = list_first_entry(&mdsc->caps_list,
139                                        struct ceph_cap, caps_item);
140                 list_del(&cap->caps_item);
141                 kmem_cache_free(ceph_cap_cachep, cap);
142         }
143         mdsc->caps_total_count = 0;
144         mdsc->caps_avail_count = 0;
145         mdsc->caps_use_count = 0;
146         mdsc->caps_reserve_count = 0;
147         mdsc->caps_min_count = 0;
148         spin_unlock(&mdsc->caps_list_lock);
149 }
150 
151 void ceph_adjust_min_caps(struct ceph_mds_client *mdsc, int delta)
152 {
153         spin_lock(&mdsc->caps_list_lock);
154         mdsc->caps_min_count += delta;
155         BUG_ON(mdsc->caps_min_count < 0);
156         spin_unlock(&mdsc->caps_list_lock);
157 }
158 
159 static void __ceph_unreserve_caps(struct ceph_mds_client *mdsc, int nr_caps)
160 {
161         struct ceph_cap *cap;
162         int i;
163 
164         if (nr_caps) {
165                 BUG_ON(mdsc->caps_reserve_count < nr_caps);
166                 mdsc->caps_reserve_count -= nr_caps;
167                 if (mdsc->caps_avail_count >=
168                     mdsc->caps_reserve_count + mdsc->caps_min_count) {
169                         mdsc->caps_total_count -= nr_caps;
170                         for (i = 0; i < nr_caps; i++) {
171                                 cap = list_first_entry(&mdsc->caps_list,
172                                         struct ceph_cap, caps_item);
173                                 list_del(&cap->caps_item);
174                                 kmem_cache_free(ceph_cap_cachep, cap);
175                         }
176                 } else {
177                         mdsc->caps_avail_count += nr_caps;
178                 }
179 
180                 dout("%s: caps %d = %d used + %d resv + %d avail\n",
181                      __func__,
182                      mdsc->caps_total_count, mdsc->caps_use_count,
183                      mdsc->caps_reserve_count, mdsc->caps_avail_count);
184                 BUG_ON(mdsc->caps_total_count != mdsc->caps_use_count +
185                                                  mdsc->caps_reserve_count +
186                                                  mdsc->caps_avail_count);
187         }
188 }
189 
190 /*
191  * Called under mdsc->mutex.
192  */
193 int ceph_reserve_caps(struct ceph_mds_client *mdsc,
194                       struct ceph_cap_reservation *ctx, int need)
195 {
196         int i, j;
197         struct ceph_cap *cap;
198         int have;
199         int alloc = 0;
200         int max_caps;
201         int err = 0;
202         bool trimmed = false;
203         struct ceph_mds_session *s;
204         LIST_HEAD(newcaps);
205 
206         dout("reserve caps ctx=%p need=%d\n", ctx, need);
207 
208         /* first reserve any caps that are already allocated */
209         spin_lock(&mdsc->caps_list_lock);
210         if (mdsc->caps_avail_count >= need)
211                 have = need;
212         else
213                 have = mdsc->caps_avail_count;
214         mdsc->caps_avail_count -= have;
215         mdsc->caps_reserve_count += have;
216         BUG_ON(mdsc->caps_total_count != mdsc->caps_use_count +
217                                          mdsc->caps_reserve_count +
218                                          mdsc->caps_avail_count);
219         spin_unlock(&mdsc->caps_list_lock);
220 
221         for (i = have; i < need; ) {
222                 cap = kmem_cache_alloc(ceph_cap_cachep, GFP_NOFS);
223                 if (cap) {
224                         list_add(&cap->caps_item, &newcaps);
225                         alloc++;
226                         i++;
227                         continue;
228                 }
229 
230                 if (!trimmed) {
231                         for (j = 0; j < mdsc->max_sessions; j++) {
232                                 s = __ceph_lookup_mds_session(mdsc, j);
233                                 if (!s)
234                                         continue;
235                                 mutex_unlock(&mdsc->mutex);
236 
237                                 mutex_lock(&s->s_mutex);
238                                 max_caps = s->s_nr_caps - (need - i);
239                                 ceph_trim_caps(mdsc, s, max_caps);
240                                 mutex_unlock(&s->s_mutex);
241 
242                                 ceph_put_mds_session(s);
243                                 mutex_lock(&mdsc->mutex);
244                         }
245                         trimmed = true;
246 
247                         spin_lock(&mdsc->caps_list_lock);
248                         if (mdsc->caps_avail_count) {
249                                 int more_have;
250                                 if (mdsc->caps_avail_count >= need - i)
251                                         more_have = need - i;
252                                 else
253                                         more_have = mdsc->caps_avail_count;
254 
255                                 i += more_have;
256                                 have += more_have;
257                                 mdsc->caps_avail_count -= more_have;
258                                 mdsc->caps_reserve_count += more_have;
259 
260                         }
261                         spin_unlock(&mdsc->caps_list_lock);
262 
263                         continue;
264                 }
265 
266                 pr_warn("reserve caps ctx=%p ENOMEM need=%d got=%d\n",
267                         ctx, need, have + alloc);
268                 err = -ENOMEM;
269                 break;
270         }
271 
272         if (!err) {
273                 BUG_ON(have + alloc != need);
274                 ctx->count = need;
275         }
276 
277         spin_lock(&mdsc->caps_list_lock);
278         mdsc->caps_total_count += alloc;
279         mdsc->caps_reserve_count += alloc;
280         list_splice(&newcaps, &mdsc->caps_list);
281 
282         BUG_ON(mdsc->caps_total_count != mdsc->caps_use_count +
283                                          mdsc->caps_reserve_count +
284                                          mdsc->caps_avail_count);
285 
286         if (err)
287                 __ceph_unreserve_caps(mdsc, have + alloc);
288 
289         spin_unlock(&mdsc->caps_list_lock);
290 
291         dout("reserve caps ctx=%p %d = %d used + %d resv + %d avail\n",
292              ctx, mdsc->caps_total_count, mdsc->caps_use_count,
293              mdsc->caps_reserve_count, mdsc->caps_avail_count);
294         return err;
295 }
296 
297 void ceph_unreserve_caps(struct ceph_mds_client *mdsc,
298                         struct ceph_cap_reservation *ctx)
299 {
300         dout("unreserve caps ctx=%p count=%d\n", ctx, ctx->count);
301         spin_lock(&mdsc->caps_list_lock);
302         __ceph_unreserve_caps(mdsc, ctx->count);
303         ctx->count = 0;
304         spin_unlock(&mdsc->caps_list_lock);
305 }
306 
307 struct ceph_cap *ceph_get_cap(struct ceph_mds_client *mdsc,
308                               struct ceph_cap_reservation *ctx)
309 {
310         struct ceph_cap *cap = NULL;
311 
312         /* temporary, until we do something about cap import/export */
313         if (!ctx) {
314                 cap = kmem_cache_alloc(ceph_cap_cachep, GFP_NOFS);
315                 if (cap) {
316                         spin_lock(&mdsc->caps_list_lock);
317                         mdsc->caps_use_count++;
318                         mdsc->caps_total_count++;
319                         spin_unlock(&mdsc->caps_list_lock);
320                 } else {
321                         spin_lock(&mdsc->caps_list_lock);
322                         if (mdsc->caps_avail_count) {
323                                 BUG_ON(list_empty(&mdsc->caps_list));
324 
325                                 mdsc->caps_avail_count--;
326                                 mdsc->caps_use_count++;
327                                 cap = list_first_entry(&mdsc->caps_list,
328                                                 struct ceph_cap, caps_item);
329                                 list_del(&cap->caps_item);
330 
331                                 BUG_ON(mdsc->caps_total_count != mdsc->caps_use_count +
332                                        mdsc->caps_reserve_count + mdsc->caps_avail_count);
333                         }
334                         spin_unlock(&mdsc->caps_list_lock);
335                 }
336 
337                 return cap;
338         }
339 
340         spin_lock(&mdsc->caps_list_lock);
341         dout("get_cap ctx=%p (%d) %d = %d used + %d resv + %d avail\n",
342              ctx, ctx->count, mdsc->caps_total_count, mdsc->caps_use_count,
343              mdsc->caps_reserve_count, mdsc->caps_avail_count);
344         BUG_ON(!ctx->count);
345         BUG_ON(ctx->count > mdsc->caps_reserve_count);
346         BUG_ON(list_empty(&mdsc->caps_list));
347 
348         ctx->count--;
349         mdsc->caps_reserve_count--;
350         mdsc->caps_use_count++;
351 
352         cap = list_first_entry(&mdsc->caps_list, struct ceph_cap, caps_item);
353         list_del(&cap->caps_item);
354 
355         BUG_ON(mdsc->caps_total_count != mdsc->caps_use_count +
356                mdsc->caps_reserve_count + mdsc->caps_avail_count);
357         spin_unlock(&mdsc->caps_list_lock);
358         return cap;
359 }
360 
361 void ceph_put_cap(struct ceph_mds_client *mdsc, struct ceph_cap *cap)
362 {
363         spin_lock(&mdsc->caps_list_lock);
364         dout("put_cap %p %d = %d used + %d resv + %d avail\n",
365              cap, mdsc->caps_total_count, mdsc->caps_use_count,
366              mdsc->caps_reserve_count, mdsc->caps_avail_count);
367         mdsc->caps_use_count--;
368         /*
369          * Keep some preallocated caps around (ceph_min_count), to
370          * avoid lots of free/alloc churn.
371          */
372         if (mdsc->caps_avail_count >= mdsc->caps_reserve_count +
373                                       mdsc->caps_min_count) {
374                 mdsc->caps_total_count--;
375                 kmem_cache_free(ceph_cap_cachep, cap);
376         } else {
377                 mdsc->caps_avail_count++;
378                 list_add(&cap->caps_item, &mdsc->caps_list);
379         }
380 
381         BUG_ON(mdsc->caps_total_count != mdsc->caps_use_count +
382                mdsc->caps_reserve_count + mdsc->caps_avail_count);
383         spin_unlock(&mdsc->caps_list_lock);
384 }
385 
386 void ceph_reservation_status(struct ceph_fs_client *fsc,
387                              int *total, int *avail, int *used, int *reserved,
388                              int *min)
389 {
390         struct ceph_mds_client *mdsc = fsc->mdsc;
391 
392         spin_lock(&mdsc->caps_list_lock);
393 
394         if (total)
395                 *total = mdsc->caps_total_count;
396         if (avail)
397                 *avail = mdsc->caps_avail_count;
398         if (used)
399                 *used = mdsc->caps_use_count;
400         if (reserved)
401                 *reserved = mdsc->caps_reserve_count;
402         if (min)
403                 *min = mdsc->caps_min_count;
404 
405         spin_unlock(&mdsc->caps_list_lock);
406 }
407 
408 /*
409  * Find ceph_cap for given mds, if any.
410  *
411  * Called with i_ceph_lock held.
412  */
413 static struct ceph_cap *__get_cap_for_mds(struct ceph_inode_info *ci, int mds)
414 {
415         struct ceph_cap *cap;
416         struct rb_node *n = ci->i_caps.rb_node;
417 
418         while (n) {
419                 cap = rb_entry(n, struct ceph_cap, ci_node);
420                 if (mds < cap->mds)
421                         n = n->rb_left;
422                 else if (mds > cap->mds)
423                         n = n->rb_right;
424                 else
425                         return cap;
426         }
427         return NULL;
428 }
429 
430 struct ceph_cap *ceph_get_cap_for_mds(struct ceph_inode_info *ci, int mds)
431 {
432         struct ceph_cap *cap;
433 
434         spin_lock(&ci->i_ceph_lock);
435         cap = __get_cap_for_mds(ci, mds);
436         spin_unlock(&ci->i_ceph_lock);
437         return cap;
438 }
439 
440 /*
441  * Return id of any MDS with a cap, preferably FILE_WR|BUFFER|EXCL, else -1.
442  */
443 static int __ceph_get_cap_mds(struct ceph_inode_info *ci)
444 {
445         struct ceph_cap *cap;
446         int mds = -1;
447         struct rb_node *p;
448 
449         /* prefer mds with WR|BUFFER|EXCL caps */
450         for (p = rb_first(&ci->i_caps); p; p = rb_next(p)) {
451                 cap = rb_entry(p, struct ceph_cap, ci_node);
452                 mds = cap->mds;
453                 if (cap->issued & (CEPH_CAP_FILE_WR |
454                                    CEPH_CAP_FILE_BUFFER |
455                                    CEPH_CAP_FILE_EXCL))
456                         break;
457         }
458         return mds;
459 }
460 
461 int ceph_get_cap_mds(struct inode *inode)
462 {
463         struct ceph_inode_info *ci = ceph_inode(inode);
464         int mds;
465         spin_lock(&ci->i_ceph_lock);
466         mds = __ceph_get_cap_mds(ceph_inode(inode));
467         spin_unlock(&ci->i_ceph_lock);
468         return mds;
469 }
470 
471 /*
472  * Called under i_ceph_lock.
473  */
474 static void __insert_cap_node(struct ceph_inode_info *ci,
475                               struct ceph_cap *new)
476 {
477         struct rb_node **p = &ci->i_caps.rb_node;
478         struct rb_node *parent = NULL;
479         struct ceph_cap *cap = NULL;
480 
481         while (*p) {
482                 parent = *p;
483                 cap = rb_entry(parent, struct ceph_cap, ci_node);
484                 if (new->mds < cap->mds)
485                         p = &(*p)->rb_left;
486                 else if (new->mds > cap->mds)
487                         p = &(*p)->rb_right;
488                 else
489                         BUG();
490         }
491 
492         rb_link_node(&new->ci_node, parent, p);
493         rb_insert_color(&new->ci_node, &ci->i_caps);
494 }
495 
496 /*
497  * (re)set cap hold timeouts, which control the delayed release
498  * of unused caps back to the MDS.  Should be called on cap use.
499  */
500 static void __cap_set_timeouts(struct ceph_mds_client *mdsc,
501                                struct ceph_inode_info *ci)
502 {
503         struct ceph_mount_options *ma = mdsc->fsc->mount_options;
504 
505         ci->i_hold_caps_min = round_jiffies(jiffies +
506                                             ma->caps_wanted_delay_min * HZ);
507         ci->i_hold_caps_max = round_jiffies(jiffies +
508                                             ma->caps_wanted_delay_max * HZ);
509         dout("__cap_set_timeouts %p min %lu max %lu\n", &ci->vfs_inode,
510              ci->i_hold_caps_min - jiffies, ci->i_hold_caps_max - jiffies);
511 }
512 
513 /*
514  * (Re)queue cap at the end of the delayed cap release list.
515  *
516  * If I_FLUSH is set, leave the inode at the front of the list.
517  *
518  * Caller holds i_ceph_lock
519  *    -> we take mdsc->cap_delay_lock
520  */
521 static void __cap_delay_requeue(struct ceph_mds_client *mdsc,
522                                 struct ceph_inode_info *ci,
523                                 bool set_timeout)
524 {
525         dout("__cap_delay_requeue %p flags %d at %lu\n", &ci->vfs_inode,
526              ci->i_ceph_flags, ci->i_hold_caps_max);
527         if (!mdsc->stopping) {
528                 spin_lock(&mdsc->cap_delay_lock);
529                 if (!list_empty(&ci->i_cap_delay_list)) {
530                         if (ci->i_ceph_flags & CEPH_I_FLUSH)
531                                 goto no_change;
532                         list_del_init(&ci->i_cap_delay_list);
533                 }
534                 if (set_timeout)
535                         __cap_set_timeouts(mdsc, ci);
536                 list_add_tail(&ci->i_cap_delay_list, &mdsc->cap_delay_list);
537 no_change:
538                 spin_unlock(&mdsc->cap_delay_lock);
539         }
540 }
541 
542 /*
543  * Queue an inode for immediate writeback.  Mark inode with I_FLUSH,
544  * indicating we should send a cap message to flush dirty metadata
545  * asap, and move to the front of the delayed cap list.
546  */
547 static void __cap_delay_requeue_front(struct ceph_mds_client *mdsc,
548                                       struct ceph_inode_info *ci)
549 {
550         dout("__cap_delay_requeue_front %p\n", &ci->vfs_inode);
551         spin_lock(&mdsc->cap_delay_lock);
552         ci->i_ceph_flags |= CEPH_I_FLUSH;
553         if (!list_empty(&ci->i_cap_delay_list))
554                 list_del_init(&ci->i_cap_delay_list);
555         list_add(&ci->i_cap_delay_list, &mdsc->cap_delay_list);
556         spin_unlock(&mdsc->cap_delay_lock);
557 }
558 
559 /*
560  * Cancel delayed work on cap.
561  *
562  * Caller must hold i_ceph_lock.
563  */
564 static void __cap_delay_cancel(struct ceph_mds_client *mdsc,
565                                struct ceph_inode_info *ci)
566 {
567         dout("__cap_delay_cancel %p\n", &ci->vfs_inode);
568         if (list_empty(&ci->i_cap_delay_list))
569                 return;
570         spin_lock(&mdsc->cap_delay_lock);
571         list_del_init(&ci->i_cap_delay_list);
572         spin_unlock(&mdsc->cap_delay_lock);
573 }
574 
575 /*
576  * Common issue checks for add_cap, handle_cap_grant.
577  */
578 static void __check_cap_issue(struct ceph_inode_info *ci, struct ceph_cap *cap,
579                               unsigned issued)
580 {
581         unsigned had = __ceph_caps_issued(ci, NULL);
582 
583         /*
584          * Each time we receive FILE_CACHE anew, we increment
585          * i_rdcache_gen.
586          */
587         if ((issued & (CEPH_CAP_FILE_CACHE|CEPH_CAP_FILE_LAZYIO)) &&
588             (had & (CEPH_CAP_FILE_CACHE|CEPH_CAP_FILE_LAZYIO)) == 0) {
589                 ci->i_rdcache_gen++;
590         }
591 
592         /*
593          * If FILE_SHARED is newly issued, mark dir not complete. We don't
594          * know what happened to this directory while we didn't have the cap.
595          * If FILE_SHARED is being revoked, also mark dir not complete. It
596          * stops on-going cached readdir.
597          */
598         if ((issued & CEPH_CAP_FILE_SHARED) != (had & CEPH_CAP_FILE_SHARED)) {
599                 if (issued & CEPH_CAP_FILE_SHARED)
600                         atomic_inc(&ci->i_shared_gen);
601                 if (S_ISDIR(ci->vfs_inode.i_mode)) {
602                         dout(" marking %p NOT complete\n", &ci->vfs_inode);
603                         __ceph_dir_clear_complete(ci);
604                 }
605         }
606 }
607 
608 /*
609  * Add a capability under the given MDS session.
610  *
611  * Caller should hold session snap_rwsem (read) and s_mutex.
612  *
613  * @fmode is the open file mode, if we are opening a file, otherwise
614  * it is < 0.  (This is so we can atomically add the cap and add an
615  * open file reference to it.)
616  */
617 void ceph_add_cap(struct inode *inode,
618                   struct ceph_mds_session *session, u64 cap_id,
619                   int fmode, unsigned issued, unsigned wanted,
620                   unsigned seq, unsigned mseq, u64 realmino, int flags,
621                   struct ceph_cap **new_cap)
622 {
623         struct ceph_mds_client *mdsc = ceph_inode_to_client(inode)->mdsc;
624         struct ceph_inode_info *ci = ceph_inode(inode);
625         struct ceph_cap *cap;
626         int mds = session->s_mds;
627         int actual_wanted;
628 
629         dout("add_cap %p mds%d cap %llx %s seq %d\n", inode,
630              session->s_mds, cap_id, ceph_cap_string(issued), seq);
631 
632         /*
633          * If we are opening the file, include file mode wanted bits
634          * in wanted.
635          */
636         if (fmode >= 0)
637                 wanted |= ceph_caps_for_mode(fmode);
638 
639         cap = __get_cap_for_mds(ci, mds);
640         if (!cap) {
641                 cap = *new_cap;
642                 *new_cap = NULL;
643 
644                 cap->issued = 0;
645                 cap->implemented = 0;
646                 cap->mds = mds;
647                 cap->mds_wanted = 0;
648                 cap->mseq = 0;
649 
650                 cap->ci = ci;
651                 __insert_cap_node(ci, cap);
652 
653                 /* add to session cap list */
654                 cap->session = session;
655                 spin_lock(&session->s_cap_lock);
656                 list_add_tail(&cap->session_caps, &session->s_caps);
657                 session->s_nr_caps++;
658                 spin_unlock(&session->s_cap_lock);
659         } else {
660                 if (cap->cap_gen < session->s_cap_gen)
661                         cap->issued = cap->implemented = CEPH_CAP_PIN;
662 
663                 /*
664                  * auth mds of the inode changed. we received the cap export
665                  * message, but still haven't received the cap import message.
666                  * handle_cap_export() updated the new auth MDS' cap.
667                  *
668                  * "ceph_seq_cmp(seq, cap->seq) <= 0" means we are processing
669                  * a message that was send before the cap import message. So
670                  * don't remove caps.
671                  */
672                 if (ceph_seq_cmp(seq, cap->seq) <= 0) {
673                         WARN_ON(cap != ci->i_auth_cap);
674                         WARN_ON(cap->cap_id != cap_id);
675                         seq = cap->seq;
676                         mseq = cap->mseq;
677                         issued |= cap->issued;
678                         flags |= CEPH_CAP_FLAG_AUTH;
679                 }
680         }
681 
682         if (!ci->i_snap_realm ||
683             ((flags & CEPH_CAP_FLAG_AUTH) &&
684              realmino != (u64)-1 && ci->i_snap_realm->ino != realmino)) {
685                 /*
686                  * add this inode to the appropriate snap realm
687                  */
688                 struct ceph_snap_realm *realm = ceph_lookup_snap_realm(mdsc,
689                                                                realmino);
690                 if (realm) {
691                         struct ceph_snap_realm *oldrealm = ci->i_snap_realm;
692                         if (oldrealm) {
693                                 spin_lock(&oldrealm->inodes_with_caps_lock);
694                                 list_del_init(&ci->i_snap_realm_item);
695                                 spin_unlock(&oldrealm->inodes_with_caps_lock);
696                         }
697 
698                         spin_lock(&realm->inodes_with_caps_lock);
699                         list_add(&ci->i_snap_realm_item,
700                                  &realm->inodes_with_caps);
701                         ci->i_snap_realm = realm;
702                         if (realm->ino == ci->i_vino.ino)
703                                 realm->inode = inode;
704                         spin_unlock(&realm->inodes_with_caps_lock);
705 
706                         if (oldrealm)
707                                 ceph_put_snap_realm(mdsc, oldrealm);
708                 } else {
709                         pr_err("ceph_add_cap: couldn't find snap realm %llx\n",
710                                realmino);
711                         WARN_ON(!realm);
712                 }
713         }
714 
715         __check_cap_issue(ci, cap, issued);
716 
717         /*
718          * If we are issued caps we don't want, or the mds' wanted
719          * value appears to be off, queue a check so we'll release
720          * later and/or update the mds wanted value.
721          */
722         actual_wanted = __ceph_caps_wanted(ci);
723         if ((wanted & ~actual_wanted) ||
724             (issued & ~actual_wanted & CEPH_CAP_ANY_WR)) {
725                 dout(" issued %s, mds wanted %s, actual %s, queueing\n",
726                      ceph_cap_string(issued), ceph_cap_string(wanted),
727                      ceph_cap_string(actual_wanted));
728                 __cap_delay_requeue(mdsc, ci, true);
729         }
730 
731         if (flags & CEPH_CAP_FLAG_AUTH) {
732                 if (!ci->i_auth_cap ||
733                     ceph_seq_cmp(ci->i_auth_cap->mseq, mseq) < 0) {
734                         ci->i_auth_cap = cap;
735                         cap->mds_wanted = wanted;
736                 }
737         } else {
738                 WARN_ON(ci->i_auth_cap == cap);
739         }
740 
741         dout("add_cap inode %p (%llx.%llx) cap %p %s now %s seq %d mds%d\n",
742              inode, ceph_vinop(inode), cap, ceph_cap_string(issued),
743              ceph_cap_string(issued|cap->issued), seq, mds);
744         cap->cap_id = cap_id;
745         cap->issued = issued;
746         cap->implemented |= issued;
747         if (ceph_seq_cmp(mseq, cap->mseq) > 0)
748                 cap->mds_wanted = wanted;
749         else
750                 cap->mds_wanted |= wanted;
751         cap->seq = seq;
752         cap->issue_seq = seq;
753         cap->mseq = mseq;
754         cap->cap_gen = session->s_cap_gen;
755 
756         if (fmode >= 0)
757                 __ceph_get_fmode(ci, fmode);
758 }
759 
760 /*
761  * Return true if cap has not timed out and belongs to the current
762  * generation of the MDS session (i.e. has not gone 'stale' due to
763  * us losing touch with the mds).
764  */
765 static int __cap_is_valid(struct ceph_cap *cap)
766 {
767         unsigned long ttl;
768         u32 gen;
769 
770         spin_lock(&cap->session->s_gen_ttl_lock);
771         gen = cap->session->s_cap_gen;
772         ttl = cap->session->s_cap_ttl;
773         spin_unlock(&cap->session->s_gen_ttl_lock);
774 
775         if (cap->cap_gen < gen || time_after_eq(jiffies, ttl)) {
776                 dout("__cap_is_valid %p cap %p issued %s "
777                      "but STALE (gen %u vs %u)\n", &cap->ci->vfs_inode,
778                      cap, ceph_cap_string(cap->issued), cap->cap_gen, gen);
779                 return 0;
780         }
781 
782         return 1;
783 }
784 
785 /*
786  * Return set of valid cap bits issued to us.  Note that caps time
787  * out, and may be invalidated in bulk if the client session times out
788  * and session->s_cap_gen is bumped.
789  */
790 int __ceph_caps_issued(struct ceph_inode_info *ci, int *implemented)
791 {
792         int have = ci->i_snap_caps;
793         struct ceph_cap *cap;
794         struct rb_node *p;
795 
796         if (implemented)
797                 *implemented = 0;
798         for (p = rb_first(&ci->i_caps); p; p = rb_next(p)) {
799                 cap = rb_entry(p, struct ceph_cap, ci_node);
800                 if (!__cap_is_valid(cap))
801                         continue;
802                 dout("__ceph_caps_issued %p cap %p issued %s\n",
803                      &ci->vfs_inode, cap, ceph_cap_string(cap->issued));
804                 have |= cap->issued;
805                 if (implemented)
806                         *implemented |= cap->implemented;
807         }
808         /*
809          * exclude caps issued by non-auth MDS, but are been revoking
810          * by the auth MDS. The non-auth MDS should be revoking/exporting
811          * these caps, but the message is delayed.
812          */
813         if (ci->i_auth_cap) {
814                 cap = ci->i_auth_cap;
815                 have &= ~cap->implemented | cap->issued;
816         }
817         return have;
818 }
819 
820 /*
821  * Get cap bits issued by caps other than @ocap
822  */
823 int __ceph_caps_issued_other(struct ceph_inode_info *ci, struct ceph_cap *ocap)
824 {
825         int have = ci->i_snap_caps;
826         struct ceph_cap *cap;
827         struct rb_node *p;
828 
829         for (p = rb_first(&ci->i_caps); p; p = rb_next(p)) {
830                 cap = rb_entry(p, struct ceph_cap, ci_node);
831                 if (cap == ocap)
832                         continue;
833                 if (!__cap_is_valid(cap))
834                         continue;
835                 have |= cap->issued;
836         }
837         return have;
838 }
839 
840 /*
841  * Move a cap to the end of the LRU (oldest caps at list head, newest
842  * at list tail).
843  */
844 static void __touch_cap(struct ceph_cap *cap)
845 {
846         struct ceph_mds_session *s = cap->session;
847 
848         spin_lock(&s->s_cap_lock);
849         if (!s->s_cap_iterator) {
850                 dout("__touch_cap %p cap %p mds%d\n", &cap->ci->vfs_inode, cap,
851                      s->s_mds);
852                 list_move_tail(&cap->session_caps, &s->s_caps);
853         } else {
854                 dout("__touch_cap %p cap %p mds%d NOP, iterating over caps\n",
855                      &cap->ci->vfs_inode, cap, s->s_mds);
856         }
857         spin_unlock(&s->s_cap_lock);
858 }
859 
860 /*
861  * Check if we hold the given mask.  If so, move the cap(s) to the
862  * front of their respective LRUs.  (This is the preferred way for
863  * callers to check for caps they want.)
864  */
865 int __ceph_caps_issued_mask(struct ceph_inode_info *ci, int mask, int touch)
866 {
867         struct ceph_cap *cap;
868         struct rb_node *p;
869         int have = ci->i_snap_caps;
870 
871         if ((have & mask) == mask) {
872                 dout("__ceph_caps_issued_mask %p snap issued %s"
873                      " (mask %s)\n", &ci->vfs_inode,
874                      ceph_cap_string(have),
875                      ceph_cap_string(mask));
876                 return 1;
877         }
878 
879         for (p = rb_first(&ci->i_caps); p; p = rb_next(p)) {
880                 cap = rb_entry(p, struct ceph_cap, ci_node);
881                 if (!__cap_is_valid(cap))
882                         continue;
883                 if ((cap->issued & mask) == mask) {
884                         dout("__ceph_caps_issued_mask %p cap %p issued %s"
885                              " (mask %s)\n", &ci->vfs_inode, cap,
886                              ceph_cap_string(cap->issued),
887                              ceph_cap_string(mask));
888                         if (touch)
889                                 __touch_cap(cap);
890                         return 1;
891                 }
892 
893                 /* does a combination of caps satisfy mask? */
894                 have |= cap->issued;
895                 if ((have & mask) == mask) {
896                         dout("__ceph_caps_issued_mask %p combo issued %s"
897                              " (mask %s)\n", &ci->vfs_inode,
898                              ceph_cap_string(cap->issued),
899                              ceph_cap_string(mask));
900                         if (touch) {
901                                 struct rb_node *q;
902 
903                                 /* touch this + preceding caps */
904                                 __touch_cap(cap);
905                                 for (q = rb_first(&ci->i_caps); q != p;
906                                      q = rb_next(q)) {
907                                         cap = rb_entry(q, struct ceph_cap,
908                                                        ci_node);
909                                         if (!__cap_is_valid(cap))
910                                                 continue;
911                                         __touch_cap(cap);
912                                 }
913                         }
914                         return 1;
915                 }
916         }
917 
918         return 0;
919 }
920 
921 /*
922  * Return true if mask caps are currently being revoked by an MDS.
923  */
924 int __ceph_caps_revoking_other(struct ceph_inode_info *ci,
925                                struct ceph_cap *ocap, int mask)
926 {
927         struct ceph_cap *cap;
928         struct rb_node *p;
929 
930         for (p = rb_first(&ci->i_caps); p; p = rb_next(p)) {
931                 cap = rb_entry(p, struct ceph_cap, ci_node);
932                 if (cap != ocap &&
933                     (cap->implemented & ~cap->issued & mask))
934                         return 1;
935         }
936         return 0;
937 }
938 
939 int ceph_caps_revoking(struct ceph_inode_info *ci, int mask)
940 {
941         struct inode *inode = &ci->vfs_inode;
942         int ret;
943 
944         spin_lock(&ci->i_ceph_lock);
945         ret = __ceph_caps_revoking_other(ci, NULL, mask);
946         spin_unlock(&ci->i_ceph_lock);
947         dout("ceph_caps_revoking %p %s = %d\n", inode,
948              ceph_cap_string(mask), ret);
949         return ret;
950 }
951 
952 int __ceph_caps_used(struct ceph_inode_info *ci)
953 {
954         int used = 0;
955         if (ci->i_pin_ref)
956                 used |= CEPH_CAP_PIN;
957         if (ci->i_rd_ref)
958                 used |= CEPH_CAP_FILE_RD;
959         if (ci->i_rdcache_ref ||
960             (!S_ISDIR(ci->vfs_inode.i_mode) && /* ignore readdir cache */
961              ci->vfs_inode.i_data.nrpages))
962                 used |= CEPH_CAP_FILE_CACHE;
963         if (ci->i_wr_ref)
964                 used |= CEPH_CAP_FILE_WR;
965         if (ci->i_wb_ref || ci->i_wrbuffer_ref)
966                 used |= CEPH_CAP_FILE_BUFFER;
967         return used;
968 }
969 
970 /*
971  * wanted, by virtue of open file modes
972  */
973 int __ceph_caps_file_wanted(struct ceph_inode_info *ci)
974 {
975         int i, bits = 0;
976         for (i = 0; i < CEPH_FILE_MODE_BITS; i++) {
977                 if (ci->i_nr_by_mode[i])
978                         bits |= 1 << i;
979         }
980         if (bits == 0)
981                 return 0;
982         return ceph_caps_for_mode(bits >> 1);
983 }
984 
985 /*
986  * Return caps we have registered with the MDS(s) as 'wanted'.
987  */
988 int __ceph_caps_mds_wanted(struct ceph_inode_info *ci, bool check)
989 {
990         struct ceph_cap *cap;
991         struct rb_node *p;
992         int mds_wanted = 0;
993 
994         for (p = rb_first(&ci->i_caps); p; p = rb_next(p)) {
995                 cap = rb_entry(p, struct ceph_cap, ci_node);
996                 if (check && !__cap_is_valid(cap))
997                         continue;
998                 if (cap == ci->i_auth_cap)
999                         mds_wanted |= cap->mds_wanted;
1000                 else
1001                         mds_wanted |= (cap->mds_wanted & ~CEPH_CAP_ANY_FILE_WR);
1002         }
1003         return mds_wanted;
1004 }
1005 
1006 /*
1007  * called under i_ceph_lock
1008  */
1009 static int __ceph_is_single_caps(struct ceph_inode_info *ci)
1010 {
1011         return rb_first(&ci->i_caps) == rb_last(&ci->i_caps);
1012 }
1013 
1014 static int __ceph_is_any_caps(struct ceph_inode_info *ci)
1015 {
1016         return !RB_EMPTY_ROOT(&ci->i_caps);
1017 }
1018 
1019 int ceph_is_any_caps(struct inode *inode)
1020 {
1021         struct ceph_inode_info *ci = ceph_inode(inode);
1022         int ret;
1023 
1024         spin_lock(&ci->i_ceph_lock);
1025         ret = __ceph_is_any_caps(ci);
1026         spin_unlock(&ci->i_ceph_lock);
1027 
1028         return ret;
1029 }
1030 
1031 static void drop_inode_snap_realm(struct ceph_inode_info *ci)
1032 {
1033         struct ceph_snap_realm *realm = ci->i_snap_realm;
1034         spin_lock(&realm->inodes_with_caps_lock);
1035         list_del_init(&ci->i_snap_realm_item);
1036         ci->i_snap_realm_counter++;
1037         ci->i_snap_realm = NULL;
1038         if (realm->ino == ci->i_vino.ino)
1039                 realm->inode = NULL;
1040         spin_unlock(&realm->inodes_with_caps_lock);
1041         ceph_put_snap_realm(ceph_sb_to_client(ci->vfs_inode.i_sb)->mdsc,
1042                             realm);
1043 }
1044 
1045 /*
1046  * Remove a cap.  Take steps to deal with a racing iterate_session_caps.
1047  *
1048  * caller should hold i_ceph_lock.
1049  * caller will not hold session s_mutex if called from destroy_inode.
1050  */
1051 void __ceph_remove_cap(struct ceph_cap *cap, bool queue_release)
1052 {
1053         struct ceph_mds_session *session = cap->session;
1054         struct ceph_inode_info *ci = cap->ci;
1055         struct ceph_mds_client *mdsc =
1056                 ceph_sb_to_client(ci->vfs_inode.i_sb)->mdsc;
1057         int removed = 0;
1058 
1059         dout("__ceph_remove_cap %p from %p\n", cap, &ci->vfs_inode);
1060 
1061         /* remove from session list */
1062         spin_lock(&session->s_cap_lock);
1063         if (session->s_cap_iterator == cap) {
1064                 /* not yet, we are iterating over this very cap */
1065                 dout("__ceph_remove_cap  delaying %p removal from session %p\n",
1066                      cap, cap->session);
1067         } else {
1068                 list_del_init(&cap->session_caps);
1069                 session->s_nr_caps--;
1070                 cap->session = NULL;
1071                 removed = 1;
1072         }
1073         /* protect backpointer with s_cap_lock: see iterate_session_caps */
1074         cap->ci = NULL;
1075 
1076         /*
1077          * s_cap_reconnect is protected by s_cap_lock. no one changes
1078          * s_cap_gen while session is in the reconnect state.
1079          */
1080         if (queue_release &&
1081             (!session->s_cap_reconnect || cap->cap_gen == session->s_cap_gen)) {
1082                 cap->queue_release = 1;
1083                 if (removed) {
1084                         list_add_tail(&cap->session_caps,
1085                                       &session->s_cap_releases);
1086                         session->s_num_cap_releases++;
1087                         removed = 0;
1088                 }
1089         } else {
1090                 cap->queue_release = 0;
1091         }
1092         cap->cap_ino = ci->i_vino.ino;
1093 
1094         spin_unlock(&session->s_cap_lock);
1095 
1096         /* remove from inode list */
1097         rb_erase(&cap->ci_node, &ci->i_caps);
1098         if (ci->i_auth_cap == cap)
1099                 ci->i_auth_cap = NULL;
1100 
1101         if (removed)
1102                 ceph_put_cap(mdsc, cap);
1103 
1104         /* when reconnect denied, we remove session caps forcibly,
1105          * i_wr_ref can be non-zero. If there are ongoing write,
1106          * keep i_snap_realm.
1107          */
1108         if (!__ceph_is_any_caps(ci) && ci->i_wr_ref == 0 && ci->i_snap_realm)
1109                 drop_inode_snap_realm(ci);
1110 
1111         if (!__ceph_is_any_real_caps(ci))
1112                 __cap_delay_cancel(mdsc, ci);
1113 }
1114 
1115 struct cap_msg_args {
1116         struct ceph_mds_session *session;
1117         u64                     ino, cid, follows;
1118         u64                     flush_tid, oldest_flush_tid, size, max_size;
1119         u64                     xattr_version;
1120         struct ceph_buffer      *xattr_buf;
1121         struct timespec64       atime, mtime, ctime;
1122         int                     op, caps, wanted, dirty;
1123         u32                     seq, issue_seq, mseq, time_warp_seq;
1124         u32                     flags;
1125         kuid_t                  uid;
1126         kgid_t                  gid;
1127         umode_t                 mode;
1128         bool                    inline_data;
1129 };
1130 
1131 /*
1132  * Build and send a cap message to the given MDS.
1133  *
1134  * Caller should be holding s_mutex.
1135  */
1136 static int send_cap_msg(struct cap_msg_args *arg)
1137 {
1138         struct ceph_mds_caps *fc;
1139         struct ceph_msg *msg;
1140         void *p;
1141         size_t extra_len;
1142         struct timespec64 zerotime = {0};
1143         struct ceph_osd_client *osdc = &arg->session->s_mdsc->fsc->client->osdc;
1144 
1145         dout("send_cap_msg %s %llx %llx caps %s wanted %s dirty %s"
1146              " seq %u/%u tid %llu/%llu mseq %u follows %lld size %llu/%llu"
1147              " xattr_ver %llu xattr_len %d\n", ceph_cap_op_name(arg->op),
1148              arg->cid, arg->ino, ceph_cap_string(arg->caps),
1149              ceph_cap_string(arg->wanted), ceph_cap_string(arg->dirty),
1150              arg->seq, arg->issue_seq, arg->flush_tid, arg->oldest_flush_tid,
1151              arg->mseq, arg->follows, arg->size, arg->max_size,
1152              arg->xattr_version,
1153              arg->xattr_buf ? (int)arg->xattr_buf->vec.iov_len : 0);
1154 
1155         /* flock buffer size + inline version + inline data size +
1156          * osd_epoch_barrier + oldest_flush_tid */
1157         extra_len = 4 + 8 + 4 + 4 + 8 + 4 + 4 + 4 + 8 + 8 + 4;
1158         msg = ceph_msg_new(CEPH_MSG_CLIENT_CAPS, sizeof(*fc) + extra_len,
1159                            GFP_NOFS, false);
1160         if (!msg)
1161                 return -ENOMEM;
1162 
1163         msg->hdr.version = cpu_to_le16(10);
1164         msg->hdr.tid = cpu_to_le64(arg->flush_tid);
1165 
1166         fc = msg->front.iov_base;
1167         memset(fc, 0, sizeof(*fc));
1168 
1169         fc->cap_id = cpu_to_le64(arg->cid);
1170         fc->op = cpu_to_le32(arg->op);
1171         fc->seq = cpu_to_le32(arg->seq);
1172         fc->issue_seq = cpu_to_le32(arg->issue_seq);
1173         fc->migrate_seq = cpu_to_le32(arg->mseq);
1174         fc->caps = cpu_to_le32(arg->caps);
1175         fc->wanted = cpu_to_le32(arg->wanted);
1176         fc->dirty = cpu_to_le32(arg->dirty);
1177         fc->ino = cpu_to_le64(arg->ino);
1178         fc->snap_follows = cpu_to_le64(arg->follows);
1179 
1180         fc->size = cpu_to_le64(arg->size);
1181         fc->max_size = cpu_to_le64(arg->max_size);
1182         ceph_encode_timespec64(&fc->mtime, &arg->mtime);
1183         ceph_encode_timespec64(&fc->atime, &arg->atime);
1184         ceph_encode_timespec64(&fc->ctime, &arg->ctime);
1185         fc->time_warp_seq = cpu_to_le32(arg->time_warp_seq);
1186 
1187         fc->uid = cpu_to_le32(from_kuid(&init_user_ns, arg->uid));
1188         fc->gid = cpu_to_le32(from_kgid(&init_user_ns, arg->gid));
1189         fc->mode = cpu_to_le32(arg->mode);
1190 
1191         fc->xattr_version = cpu_to_le64(arg->xattr_version);
1192         if (arg->xattr_buf) {
1193                 msg->middle = ceph_buffer_get(arg->xattr_buf);
1194                 fc->xattr_len = cpu_to_le32(arg->xattr_buf->vec.iov_len);
1195                 msg->hdr.middle_len = cpu_to_le32(arg->xattr_buf->vec.iov_len);
1196         }
1197 
1198         p = fc + 1;
1199         /* flock buffer size (version 2) */
1200         ceph_encode_32(&p, 0);
1201         /* inline version (version 4) */
1202         ceph_encode_64(&p, arg->inline_data ? 0 : CEPH_INLINE_NONE);
1203         /* inline data size */
1204         ceph_encode_32(&p, 0);
1205         /*
1206          * osd_epoch_barrier (version 5)
1207          * The epoch_barrier is protected osdc->lock, so READ_ONCE here in
1208          * case it was recently changed
1209          */
1210         ceph_encode_32(&p, READ_ONCE(osdc->epoch_barrier));
1211         /* oldest_flush_tid (version 6) */
1212         ceph_encode_64(&p, arg->oldest_flush_tid);
1213 
1214         /*
1215          * caller_uid/caller_gid (version 7)
1216          *
1217          * Currently, we don't properly track which caller dirtied the caps
1218          * last, and force a flush of them when there is a conflict. For now,
1219          * just set this to 0:0, to emulate how the MDS has worked up to now.
1220          */
1221         ceph_encode_32(&p, 0);
1222         ceph_encode_32(&p, 0);
1223 
1224         /* pool namespace (version 8) (mds always ignores this) */
1225         ceph_encode_32(&p, 0);
1226 
1227         /*
1228          * btime and change_attr (version 9)
1229          *
1230          * We just zero these out for now, as the MDS ignores them unless
1231          * the requisite feature flags are set (which we don't do yet).
1232          */
1233         ceph_encode_timespec64(p, &zerotime);
1234         p += sizeof(struct ceph_timespec);
1235         ceph_encode_64(&p, 0);
1236 
1237         /* Advisory flags (version 10) */
1238         ceph_encode_32(&p, arg->flags);
1239 
1240         ceph_con_send(&arg->session->s_con, msg);
1241         return 0;
1242 }
1243 
1244 /*
1245  * Queue cap releases when an inode is dropped from our cache.  Since
1246  * inode is about to be destroyed, there is no need for i_ceph_lock.
1247  */
1248 void ceph_queue_caps_release(struct inode *inode)
1249 {
1250         struct ceph_inode_info *ci = ceph_inode(inode);
1251         struct rb_node *p;
1252 
1253         p = rb_first(&ci->i_caps);
1254         while (p) {
1255                 struct ceph_cap *cap = rb_entry(p, struct ceph_cap, ci_node);
1256                 p = rb_next(p);
1257                 __ceph_remove_cap(cap, true);
1258         }
1259 }
1260 
1261 /*
1262  * Send a cap msg on the given inode.  Update our caps state, then
1263  * drop i_ceph_lock and send the message.
1264  *
1265  * Make note of max_size reported/requested from mds, revoked caps
1266  * that have now been implemented.
1267  *
1268  * Make half-hearted attempt ot to invalidate page cache if we are
1269  * dropping RDCACHE.  Note that this will leave behind locked pages
1270  * that we'll then need to deal with elsewhere.
1271  *
1272  * Return non-zero if delayed release, or we experienced an error
1273  * such that the caller should requeue + retry later.
1274  *
1275  * called with i_ceph_lock, then drops it.
1276  * caller should hold snap_rwsem (read), s_mutex.
1277  */
1278 static int __send_cap(struct ceph_mds_client *mdsc, struct ceph_cap *cap,
1279                       int op, bool sync, int used, int want, int retain,
1280                       int flushing, u64 flush_tid, u64 oldest_flush_tid)
1281         __releases(cap->ci->i_ceph_lock)
1282 {
1283         struct ceph_inode_info *ci = cap->ci;
1284         struct inode *inode = &ci->vfs_inode;
1285         struct cap_msg_args arg;
1286         int held, revoking;
1287         int wake = 0;
1288         int delayed = 0;
1289         int ret;
1290 
1291         held = cap->issued | cap->implemented;
1292         revoking = cap->implemented & ~cap->issued;
1293         retain &= ~revoking;
1294 
1295         dout("__send_cap %p cap %p session %p %s -> %s (revoking %s)\n",
1296              inode, cap, cap->session,
1297              ceph_cap_string(held), ceph_cap_string(held & retain),
1298              ceph_cap_string(revoking));
1299         BUG_ON((retain & CEPH_CAP_PIN) == 0);
1300 
1301         arg.session = cap->session;
1302 
1303         /* don't release wanted unless we've waited a bit. */
1304         if ((ci->i_ceph_flags & CEPH_I_NODELAY) == 0 &&
1305             time_before(jiffies, ci->i_hold_caps_min)) {
1306                 dout(" delaying issued %s -> %s, wanted %s -> %s on send\n",
1307                      ceph_cap_string(cap->issued),
1308                      ceph_cap_string(cap->issued & retain),
1309                      ceph_cap_string(cap->mds_wanted),
1310                      ceph_cap_string(want));
1311                 want |= cap->mds_wanted;
1312                 retain |= cap->issued;
1313                 delayed = 1;
1314         }
1315         ci->i_ceph_flags &= ~(CEPH_I_NODELAY | CEPH_I_FLUSH);
1316         if (want & ~cap->mds_wanted) {
1317                 /* user space may open/close single file frequently.
1318                  * This avoids droping mds_wanted immediately after
1319                  * requesting new mds_wanted.
1320                  */
1321                 __cap_set_timeouts(mdsc, ci);
1322         }
1323 
1324         cap->issued &= retain;  /* drop bits we don't want */
1325         if (cap->implemented & ~cap->issued) {
1326                 /*
1327                  * Wake up any waiters on wanted -> needed transition.
1328                  * This is due to the weird transition from buffered
1329                  * to sync IO... we need to flush dirty pages _before_
1330                  * allowing sync writes to avoid reordering.
1331                  */
1332                 wake = 1;
1333         }
1334         cap->implemented &= cap->issued | used;
1335         cap->mds_wanted = want;
1336 
1337         arg.ino = ceph_vino(inode).ino;
1338         arg.cid = cap->cap_id;
1339         arg.follows = flushing ? ci->i_head_snapc->seq : 0;
1340         arg.flush_tid = flush_tid;
1341         arg.oldest_flush_tid = oldest_flush_tid;
1342 
1343         arg.size = inode->i_size;
1344         ci->i_reported_size = arg.size;
1345         arg.max_size = ci->i_wanted_max_size;
1346         ci->i_requested_max_size = arg.max_size;
1347 
1348         if (flushing & CEPH_CAP_XATTR_EXCL) {
1349                 __ceph_build_xattrs_blob(ci);
1350                 arg.xattr_version = ci->i_xattrs.version;
1351                 arg.xattr_buf = ci->i_xattrs.blob;
1352         } else {
1353                 arg.xattr_buf = NULL;
1354         }
1355 
1356         arg.mtime = inode->i_mtime;
1357         arg.atime = inode->i_atime;
1358         arg.ctime = inode->i_ctime;
1359 
1360         arg.op = op;
1361         arg.caps = cap->implemented;
1362         arg.wanted = want;
1363         arg.dirty = flushing;
1364 
1365         arg.seq = cap->seq;
1366         arg.issue_seq = cap->issue_seq;
1367         arg.mseq = cap->mseq;
1368         arg.time_warp_seq = ci->i_time_warp_seq;
1369 
1370         arg.uid = inode->i_uid;
1371         arg.gid = inode->i_gid;
1372         arg.mode = inode->i_mode;
1373 
1374         arg.inline_data = ci->i_inline_version != CEPH_INLINE_NONE;
1375         if (list_empty(&ci->i_cap_snaps))
1376                 arg.flags = CEPH_CLIENT_CAPS_NO_CAPSNAP;
1377         else
1378                 arg.flags = CEPH_CLIENT_CAPS_PENDING_CAPSNAP;
1379         if (sync)
1380                 arg.flags |= CEPH_CLIENT_CAPS_SYNC;
1381 
1382         spin_unlock(&ci->i_ceph_lock);
1383 
1384         ret = send_cap_msg(&arg);
1385         if (ret < 0) {
1386                 dout("error sending cap msg, must requeue %p\n", inode);
1387                 delayed = 1;
1388         }
1389 
1390         if (wake)
1391                 wake_up_all(&ci->i_cap_wq);
1392 
1393         return delayed;
1394 }
1395 
1396 static inline int __send_flush_snap(struct inode *inode,
1397                                     struct ceph_mds_session *session,
1398                                     struct ceph_cap_snap *capsnap,
1399                                     u32 mseq, u64 oldest_flush_tid)
1400 {
1401         struct cap_msg_args     arg;
1402 
1403         arg.session = session;
1404         arg.ino = ceph_vino(inode).ino;
1405         arg.cid = 0;
1406         arg.follows = capsnap->follows;
1407         arg.flush_tid = capsnap->cap_flush.tid;
1408         arg.oldest_flush_tid = oldest_flush_tid;
1409 
1410         arg.size = capsnap->size;
1411         arg.max_size = 0;
1412         arg.xattr_version = capsnap->xattr_version;
1413         arg.xattr_buf = capsnap->xattr_blob;
1414 
1415         arg.atime = capsnap->atime;
1416         arg.mtime = capsnap->mtime;
1417         arg.ctime = capsnap->ctime;
1418 
1419         arg.op = CEPH_CAP_OP_FLUSHSNAP;
1420         arg.caps = capsnap->issued;
1421         arg.wanted = 0;
1422         arg.dirty = capsnap->dirty;
1423 
1424         arg.seq = 0;
1425         arg.issue_seq = 0;
1426         arg.mseq = mseq;
1427         arg.time_warp_seq = capsnap->time_warp_seq;
1428 
1429         arg.uid = capsnap->uid;
1430         arg.gid = capsnap->gid;
1431         arg.mode = capsnap->mode;
1432 
1433         arg.inline_data = capsnap->inline_data;
1434         arg.flags = 0;
1435 
1436         return send_cap_msg(&arg);
1437 }
1438 
1439 /*
1440  * When a snapshot is taken, clients accumulate dirty metadata on
1441  * inodes with capabilities in ceph_cap_snaps to describe the file
1442  * state at the time the snapshot was taken.  This must be flushed
1443  * asynchronously back to the MDS once sync writes complete and dirty
1444  * data is written out.
1445  *
1446  * Called under i_ceph_lock.  Takes s_mutex as needed.
1447  */
1448 static void __ceph_flush_snaps(struct ceph_inode_info *ci,
1449                                struct ceph_mds_session *session)
1450                 __releases(ci->i_ceph_lock)
1451                 __acquires(ci->i_ceph_lock)
1452 {
1453         struct inode *inode = &ci->vfs_inode;
1454         struct ceph_mds_client *mdsc = session->s_mdsc;
1455         struct ceph_cap_snap *capsnap;
1456         u64 oldest_flush_tid = 0;
1457         u64 first_tid = 1, last_tid = 0;
1458 
1459         dout("__flush_snaps %p session %p\n", inode, session);
1460 
1461         list_for_each_entry(capsnap, &ci->i_cap_snaps, ci_item) {
1462                 /*
1463                  * we need to wait for sync writes to complete and for dirty
1464                  * pages to be written out.
1465                  */
1466                 if (capsnap->dirty_pages || capsnap->writing)
1467                         break;
1468 
1469                 /* should be removed by ceph_try_drop_cap_snap() */
1470                 BUG_ON(!capsnap->need_flush);
1471 
1472                 /* only flush each capsnap once */
1473                 if (capsnap->cap_flush.tid > 0) {
1474                         dout(" already flushed %p, skipping\n", capsnap);
1475                         continue;
1476                 }
1477 
1478                 spin_lock(&mdsc->cap_dirty_lock);
1479                 capsnap->cap_flush.tid = ++mdsc->last_cap_flush_tid;
1480                 list_add_tail(&capsnap->cap_flush.g_list,
1481                               &mdsc->cap_flush_list);
1482                 if (oldest_flush_tid == 0)
1483                         oldest_flush_tid = __get_oldest_flush_tid(mdsc);
1484                 if (list_empty(&ci->i_flushing_item)) {
1485                         list_add_tail(&ci->i_flushing_item,
1486                                       &session->s_cap_flushing);
1487                 }
1488                 spin_unlock(&mdsc->cap_dirty_lock);
1489 
1490                 list_add_tail(&capsnap->cap_flush.i_list,
1491                               &ci->i_cap_flush_list);
1492 
1493                 if (first_tid == 1)
1494                         first_tid = capsnap->cap_flush.tid;
1495                 last_tid = capsnap->cap_flush.tid;
1496         }
1497 
1498         ci->i_ceph_flags &= ~CEPH_I_FLUSH_SNAPS;
1499 
1500         while (first_tid <= last_tid) {
1501                 struct ceph_cap *cap = ci->i_auth_cap;
1502                 struct ceph_cap_flush *cf;
1503                 int ret;
1504 
1505                 if (!(cap && cap->session == session)) {
1506                         dout("__flush_snaps %p auth cap %p not mds%d, "
1507                              "stop\n", inode, cap, session->s_mds);
1508                         break;
1509                 }
1510 
1511                 ret = -ENOENT;
1512                 list_for_each_entry(cf, &ci->i_cap_flush_list, i_list) {
1513                         if (cf->tid >= first_tid) {
1514                                 ret = 0;
1515                                 break;
1516                         }
1517                 }
1518                 if (ret < 0)
1519                         break;
1520 
1521                 first_tid = cf->tid + 1;
1522 
1523                 capsnap = container_of(cf, struct ceph_cap_snap, cap_flush);
1524                 refcount_inc(&capsnap->nref);
1525                 spin_unlock(&ci->i_ceph_lock);
1526 
1527                 dout("__flush_snaps %p capsnap %p tid %llu %s\n",
1528                      inode, capsnap, cf->tid, ceph_cap_string(capsnap->dirty));
1529 
1530                 ret = __send_flush_snap(inode, session, capsnap, cap->mseq,
1531                                         oldest_flush_tid);
1532                 if (ret < 0) {
1533                         pr_err("__flush_snaps: error sending cap flushsnap, "
1534                                "ino (%llx.%llx) tid %llu follows %llu\n",
1535                                 ceph_vinop(inode), cf->tid, capsnap->follows);
1536                 }
1537 
1538                 ceph_put_cap_snap(capsnap);
1539                 spin_lock(&ci->i_ceph_lock);
1540         }
1541 }
1542 
1543 void ceph_flush_snaps(struct ceph_inode_info *ci,
1544                       struct ceph_mds_session **psession)
1545 {
1546         struct inode *inode = &ci->vfs_inode;
1547         struct ceph_mds_client *mdsc = ceph_inode_to_client(inode)->mdsc;
1548         struct ceph_mds_session *session = NULL;
1549         int mds;
1550 
1551         dout("ceph_flush_snaps %p\n", inode);
1552         if (psession)
1553                 session = *psession;
1554 retry:
1555         spin_lock(&ci->i_ceph_lock);
1556         if (!(ci->i_ceph_flags & CEPH_I_FLUSH_SNAPS)) {
1557                 dout(" no capsnap needs flush, doing nothing\n");
1558                 goto out;
1559         }
1560         if (!ci->i_auth_cap) {
1561                 dout(" no auth cap (migrating?), doing nothing\n");
1562                 goto out;
1563         }
1564 
1565         mds = ci->i_auth_cap->session->s_mds;
1566         if (session && session->s_mds != mds) {
1567                 dout(" oops, wrong session %p mutex\n", session);
1568                 mutex_unlock(&session->s_mutex);
1569                 ceph_put_mds_session(session);
1570                 session = NULL;
1571         }
1572         if (!session) {
1573                 spin_unlock(&ci->i_ceph_lock);
1574                 mutex_lock(&mdsc->mutex);
1575                 session = __ceph_lookup_mds_session(mdsc, mds);
1576                 mutex_unlock(&mdsc->mutex);
1577                 if (session) {
1578                         dout(" inverting session/ino locks on %p\n", session);
1579                         mutex_lock(&session->s_mutex);
1580                 }
1581                 goto retry;
1582         }
1583 
1584         // make sure flushsnap messages are sent in proper order.
1585         if (ci->i_ceph_flags & CEPH_I_KICK_FLUSH) {
1586                 __kick_flushing_caps(mdsc, session, ci, 0);
1587                 ci->i_ceph_flags &= ~CEPH_I_KICK_FLUSH;
1588         }
1589 
1590         __ceph_flush_snaps(ci, session);
1591 out:
1592         spin_unlock(&ci->i_ceph_lock);
1593 
1594         if (psession) {
1595                 *psession = session;
1596         } else if (session) {
1597                 mutex_unlock(&session->s_mutex);
1598                 ceph_put_mds_session(session);
1599         }
1600         /* we flushed them all; remove this inode from the queue */
1601         spin_lock(&mdsc->snap_flush_lock);
1602         list_del_init(&ci->i_snap_flush_item);
1603         spin_unlock(&mdsc->snap_flush_lock);
1604 }
1605 
1606 /*
1607  * Mark caps dirty.  If inode is newly dirty, return the dirty flags.
1608  * Caller is then responsible for calling __mark_inode_dirty with the
1609  * returned flags value.
1610  */
1611 int __ceph_mark_dirty_caps(struct ceph_inode_info *ci, int mask,
1612                            struct ceph_cap_flush **pcf)
1613 {
1614         struct ceph_mds_client *mdsc =
1615                 ceph_sb_to_client(ci->vfs_inode.i_sb)->mdsc;
1616         struct inode *inode = &ci->vfs_inode;
1617         int was = ci->i_dirty_caps;
1618         int dirty = 0;
1619 
1620         if (!ci->i_auth_cap) {
1621                 pr_warn("__mark_dirty_caps %p %llx mask %s, "
1622                         "but no auth cap (session was closed?)\n",
1623                         inode, ceph_ino(inode), ceph_cap_string(mask));
1624                 return 0;
1625         }
1626 
1627         dout("__mark_dirty_caps %p %s dirty %s -> %s\n", &ci->vfs_inode,
1628              ceph_cap_string(mask), ceph_cap_string(was),
1629              ceph_cap_string(was | mask));
1630         ci->i_dirty_caps |= mask;
1631         if (was == 0) {
1632                 WARN_ON_ONCE(ci->i_prealloc_cap_flush);
1633                 swap(ci->i_prealloc_cap_flush, *pcf);
1634 
1635                 if (!ci->i_head_snapc) {
1636                         WARN_ON_ONCE(!rwsem_is_locked(&mdsc->snap_rwsem));
1637                         ci->i_head_snapc = ceph_get_snap_context(
1638                                 ci->i_snap_realm->cached_context);
1639                 }
1640                 dout(" inode %p now dirty snapc %p auth cap %p\n",
1641                      &ci->vfs_inode, ci->i_head_snapc, ci->i_auth_cap);
1642                 BUG_ON(!list_empty(&ci->i_dirty_item));
1643                 spin_lock(&mdsc->cap_dirty_lock);
1644                 list_add(&ci->i_dirty_item, &mdsc->cap_dirty);
1645                 spin_unlock(&mdsc->cap_dirty_lock);
1646                 if (ci->i_flushing_caps == 0) {
1647                         ihold(inode);
1648                         dirty |= I_DIRTY_SYNC;
1649                 }
1650         } else {
1651                 WARN_ON_ONCE(!ci->i_prealloc_cap_flush);
1652         }
1653         BUG_ON(list_empty(&ci->i_dirty_item));
1654         if (((was | ci->i_flushing_caps) & CEPH_CAP_FILE_BUFFER) &&
1655             (mask & CEPH_CAP_FILE_BUFFER))
1656                 dirty |= I_DIRTY_DATASYNC;
1657         __cap_delay_requeue(mdsc, ci, true);
1658         return dirty;
1659 }
1660 
1661 struct ceph_cap_flush *ceph_alloc_cap_flush(void)
1662 {
1663         return kmem_cache_alloc(ceph_cap_flush_cachep, GFP_KERNEL);
1664 }
1665 
1666 void ceph_free_cap_flush(struct ceph_cap_flush *cf)
1667 {
1668         if (cf)
1669                 kmem_cache_free(ceph_cap_flush_cachep, cf);
1670 }
1671 
1672 static u64 __get_oldest_flush_tid(struct ceph_mds_client *mdsc)
1673 {
1674         if (!list_empty(&mdsc->cap_flush_list)) {
1675                 struct ceph_cap_flush *cf =
1676                         list_first_entry(&mdsc->cap_flush_list,
1677                                          struct ceph_cap_flush, g_list);
1678                 return cf->tid;
1679         }
1680         return 0;
1681 }
1682 
1683 /*
1684  * Remove cap_flush from the mdsc's or inode's flushing cap list.
1685  * Return true if caller needs to wake up flush waiters.
1686  */
1687 static bool __finish_cap_flush(struct ceph_mds_client *mdsc,
1688                                struct ceph_inode_info *ci,
1689                                struct ceph_cap_flush *cf)
1690 {
1691         struct ceph_cap_flush *prev;
1692         bool wake = cf->wake;
1693         if (mdsc) {
1694                 /* are there older pending cap flushes? */
1695                 if (wake && cf->g_list.prev != &mdsc->cap_flush_list) {
1696                         prev = list_prev_entry(cf, g_list);
1697                         prev->wake = true;
1698                         wake = false;
1699                 }
1700                 list_del(&cf->g_list);
1701         } else if (ci) {
1702                 if (wake && cf->i_list.prev != &ci->i_cap_flush_list) {
1703                         prev = list_prev_entry(cf, i_list);
1704                         prev->wake = true;
1705                         wake = false;
1706                 }
1707                 list_del(&cf->i_list);
1708         } else {
1709                 BUG_ON(1);
1710         }
1711         return wake;
1712 }
1713 
1714 /*
1715  * Add dirty inode to the flushing list.  Assigned a seq number so we
1716  * can wait for caps to flush without starving.
1717  *
1718  * Called under i_ceph_lock.
1719  */
1720 static int __mark_caps_flushing(struct inode *inode,
1721                                 struct ceph_mds_session *session, bool wake,
1722                                 u64 *flush_tid, u64 *oldest_flush_tid)
1723 {
1724         struct ceph_mds_client *mdsc = ceph_sb_to_client(inode->i_sb)->mdsc;
1725         struct ceph_inode_info *ci = ceph_inode(inode);
1726         struct ceph_cap_flush *cf = NULL;
1727         int flushing;
1728 
1729         BUG_ON(ci->i_dirty_caps == 0);
1730         BUG_ON(list_empty(&ci->i_dirty_item));
1731         BUG_ON(!ci->i_prealloc_cap_flush);
1732 
1733         flushing = ci->i_dirty_caps;
1734         dout("__mark_caps_flushing flushing %s, flushing_caps %s -> %s\n",
1735              ceph_cap_string(flushing),
1736              ceph_cap_string(ci->i_flushing_caps),
1737              ceph_cap_string(ci->i_flushing_caps | flushing));
1738         ci->i_flushing_caps |= flushing;
1739         ci->i_dirty_caps = 0;
1740         dout(" inode %p now !dirty\n", inode);
1741 
1742         swap(cf, ci->i_prealloc_cap_flush);
1743         cf->caps = flushing;
1744         cf->wake = wake;
1745 
1746         spin_lock(&mdsc->cap_dirty_lock);
1747         list_del_init(&ci->i_dirty_item);
1748 
1749         cf->tid = ++mdsc->last_cap_flush_tid;
1750         list_add_tail(&cf->g_list, &mdsc->cap_flush_list);
1751         *oldest_flush_tid = __get_oldest_flush_tid(mdsc);
1752 
1753         if (list_empty(&ci->i_flushing_item)) {
1754                 list_add_tail(&ci->i_flushing_item, &session->s_cap_flushing);
1755                 mdsc->num_cap_flushing++;
1756         }
1757         spin_unlock(&mdsc->cap_dirty_lock);
1758 
1759         list_add_tail(&cf->i_list, &ci->i_cap_flush_list);
1760 
1761         *flush_tid = cf->tid;
1762         return flushing;
1763 }
1764 
1765 /*
1766  * try to invalidate mapping pages without blocking.
1767  */
1768 static int try_nonblocking_invalidate(struct inode *inode)
1769 {
1770         struct ceph_inode_info *ci = ceph_inode(inode);
1771         u32 invalidating_gen = ci->i_rdcache_gen;
1772 
1773         spin_unlock(&ci->i_ceph_lock);
1774         invalidate_mapping_pages(&inode->i_data, 0, -1);
1775         spin_lock(&ci->i_ceph_lock);
1776 
1777         if (inode->i_data.nrpages == 0 &&
1778             invalidating_gen == ci->i_rdcache_gen) {
1779                 /* success. */
1780                 dout("try_nonblocking_invalidate %p success\n", inode);
1781                 /* save any racing async invalidate some trouble */
1782                 ci->i_rdcache_revoking = ci->i_rdcache_gen - 1;
1783                 return 0;
1784         }
1785         dout("try_nonblocking_invalidate %p failed\n", inode);
1786         return -1;
1787 }
1788 
1789 bool __ceph_should_report_size(struct ceph_inode_info *ci)
1790 {
1791         loff_t size = ci->vfs_inode.i_size;
1792         /* mds will adjust max size according to the reported size */
1793         if (ci->i_flushing_caps & CEPH_CAP_FILE_WR)
1794                 return false;
1795         if (size >= ci->i_max_size)
1796                 return true;
1797         /* half of previous max_size increment has been used */
1798         if (ci->i_max_size > ci->i_reported_size &&
1799             (size << 1) >= ci->i_max_size + ci->i_reported_size)
1800                 return true;
1801         return false;
1802 }
1803 
1804 /*
1805  * Swiss army knife function to examine currently used and wanted
1806  * versus held caps.  Release, flush, ack revoked caps to mds as
1807  * appropriate.
1808  *
1809  *  CHECK_CAPS_NODELAY - caller is delayed work and we should not delay
1810  *    cap release further.
1811  *  CHECK_CAPS_AUTHONLY - we should only check the auth cap
1812  *  CHECK_CAPS_FLUSH - we should flush any dirty caps immediately, without
1813  *    further delay.
1814  */
1815 void ceph_check_caps(struct ceph_inode_info *ci, int flags,
1816                      struct ceph_mds_session *session)
1817 {
1818         struct ceph_fs_client *fsc = ceph_inode_to_client(&ci->vfs_inode);
1819         struct ceph_mds_client *mdsc = fsc->mdsc;
1820         struct inode *inode = &ci->vfs_inode;
1821         struct ceph_cap *cap;
1822         u64 flush_tid, oldest_flush_tid;
1823         int file_wanted, used, cap_used;
1824         int took_snap_rwsem = 0;             /* true if mdsc->snap_rwsem held */
1825         int issued, implemented, want, retain, revoking, flushing = 0;
1826         int mds = -1;   /* keep track of how far we've gone through i_caps list
1827                            to avoid an infinite loop on retry */
1828         struct rb_node *p;
1829         int delayed = 0, sent = 0;
1830         bool no_delay = flags & CHECK_CAPS_NODELAY;
1831         bool queue_invalidate = false;
1832         bool tried_invalidate = false;
1833 
1834         /* if we are unmounting, flush any unused caps immediately. */
1835         if (mdsc->stopping)
1836                 no_delay = true;
1837 
1838         spin_lock(&ci->i_ceph_lock);
1839 
1840         if (ci->i_ceph_flags & CEPH_I_FLUSH)
1841                 flags |= CHECK_CAPS_FLUSH;
1842 
1843         if (!(flags & CHECK_CAPS_AUTHONLY) ||
1844             (ci->i_auth_cap && __ceph_is_single_caps(ci)))
1845                 __cap_delay_cancel(mdsc, ci);
1846 
1847         goto retry_locked;
1848 retry:
1849         spin_lock(&ci->i_ceph_lock);
1850 retry_locked:
1851         file_wanted = __ceph_caps_file_wanted(ci);
1852         used = __ceph_caps_used(ci);
1853         issued = __ceph_caps_issued(ci, &implemented);
1854         revoking = implemented & ~issued;
1855 
1856         want = file_wanted;
1857         retain = file_wanted | used | CEPH_CAP_PIN;
1858         if (!mdsc->stopping && inode->i_nlink > 0) {
1859                 if (file_wanted) {
1860                         retain |= CEPH_CAP_ANY;       /* be greedy */
1861                 } else if (S_ISDIR(inode->i_mode) &&
1862                            (issued & CEPH_CAP_FILE_SHARED) &&
1863                            __ceph_dir_is_complete(ci)) {
1864                         /*
1865                          * If a directory is complete, we want to keep
1866                          * the exclusive cap. So that MDS does not end up
1867                          * revoking the shared cap on every create/unlink
1868                          * operation.
1869                          */
1870                         if (IS_RDONLY(inode))
1871                                 want = CEPH_CAP_ANY_SHARED;
1872                         else
1873                                 want = CEPH_CAP_ANY_SHARED | CEPH_CAP_FILE_EXCL;
1874                         retain |= want;
1875                 } else {
1876 
1877                         retain |= CEPH_CAP_ANY_SHARED;
1878                         /*
1879                          * keep RD only if we didn't have the file open RW,
1880                          * because then the mds would revoke it anyway to
1881                          * journal max_size=0.
1882                          */
1883                         if (ci->i_max_size == 0)
1884                                 retain |= CEPH_CAP_ANY_RD;
1885                 }
1886         }
1887 
1888         dout("check_caps %p file_want %s used %s dirty %s flushing %s"
1889              " issued %s revoking %s retain %s %s%s%s\n", inode,
1890              ceph_cap_string(file_wanted),
1891              ceph_cap_string(used), ceph_cap_string(ci->i_dirty_caps),
1892              ceph_cap_string(ci->i_flushing_caps),
1893              ceph_cap_string(issued), ceph_cap_string(revoking),
1894              ceph_cap_string(retain),
1895              (flags & CHECK_CAPS_AUTHONLY) ? " AUTHONLY" : "",
1896              (flags & CHECK_CAPS_NODELAY) ? " NODELAY" : "",
1897              (flags & CHECK_CAPS_FLUSH) ? " FLUSH" : "");
1898 
1899         /*
1900          * If we no longer need to hold onto old our caps, and we may
1901          * have cached pages, but don't want them, then try to invalidate.
1902          * If we fail, it's because pages are locked.... try again later.
1903          */
1904         if ((!no_delay || mdsc->stopping) &&
1905             !S_ISDIR(inode->i_mode) &&          /* ignore readdir cache */
1906             !(ci->i_wb_ref || ci->i_wrbuffer_ref) &&   /* no dirty pages... */
1907             inode->i_data.nrpages &&            /* have cached pages */
1908             (revoking & (CEPH_CAP_FILE_CACHE|
1909                          CEPH_CAP_FILE_LAZYIO)) && /*  or revoking cache */
1910             !tried_invalidate) {
1911                 dout("check_caps trying to invalidate on %p\n", inode);
1912                 if (try_nonblocking_invalidate(inode) < 0) {
1913                         dout("check_caps queuing invalidate\n");
1914                         queue_invalidate = true;
1915                         ci->i_rdcache_revoking = ci->i_rdcache_gen;
1916                 }
1917                 tried_invalidate = true;
1918                 goto retry_locked;
1919         }
1920 
1921         for (p = rb_first(&ci->i_caps); p; p = rb_next(p)) {
1922                 cap = rb_entry(p, struct ceph_cap, ci_node);
1923 
1924                 /* avoid looping forever */
1925                 if (mds >= cap->mds ||
1926                     ((flags & CHECK_CAPS_AUTHONLY) && cap != ci->i_auth_cap))
1927                         continue;
1928 
1929                 /* NOTE: no side-effects allowed, until we take s_mutex */
1930 
1931                 cap_used = used;
1932                 if (ci->i_auth_cap && cap != ci->i_auth_cap)
1933                         cap_used &= ~ci->i_auth_cap->issued;
1934 
1935                 revoking = cap->implemented & ~cap->issued;
1936                 dout(" mds%d cap %p used %s issued %s implemented %s revoking %s\n",
1937                      cap->mds, cap, ceph_cap_string(cap_used),
1938                      ceph_cap_string(cap->issued),
1939                      ceph_cap_string(cap->implemented),
1940                      ceph_cap_string(revoking));
1941 
1942                 if (cap == ci->i_auth_cap &&
1943                     (cap->issued & CEPH_CAP_FILE_WR)) {
1944                         /* request larger max_size from MDS? */
1945                         if (ci->i_wanted_max_size > ci->i_max_size &&
1946                             ci->i_wanted_max_size > ci->i_requested_max_size) {
1947                                 dout("requesting new max_size\n");
1948                                 goto ack;
1949                         }
1950 
1951                         /* approaching file_max? */
1952                         if (__ceph_should_report_size(ci)) {
1953                                 dout("i_size approaching max_size\n");
1954                                 goto ack;
1955                         }
1956                 }
1957                 /* flush anything dirty? */
1958                 if (cap == ci->i_auth_cap) {
1959                         if ((flags & CHECK_CAPS_FLUSH) && ci->i_dirty_caps) {
1960                                 dout("flushing dirty caps\n");
1961                                 goto ack;
1962                         }
1963                         if (ci->i_ceph_flags & CEPH_I_FLUSH_SNAPS) {
1964                                 dout("flushing snap caps\n");
1965                                 goto ack;
1966                         }
1967                 }
1968 
1969                 /* completed revocation? going down and there are no caps? */
1970                 if (revoking && (revoking & cap_used) == 0) {
1971                         dout("completed revocation of %s\n",
1972                              ceph_cap_string(cap->implemented & ~cap->issued));
1973                         goto ack;
1974                 }
1975 
1976                 /* want more caps from mds? */
1977                 if (want & ~(cap->mds_wanted | cap->issued))
1978                         goto ack;
1979 
1980                 /* things we might delay */
1981                 if ((cap->issued & ~retain) == 0)
1982                         continue;     /* nope, all good */
1983 
1984                 if (no_delay)
1985                         goto ack;
1986 
1987                 /* delay? */
1988                 if ((ci->i_ceph_flags & CEPH_I_NODELAY) == 0 &&
1989                     time_before(jiffies, ci->i_hold_caps_max)) {
1990                         dout(" delaying issued %s -> %s, wanted %s -> %s\n",
1991                              ceph_cap_string(cap->issued),
1992                              ceph_cap_string(cap->issued & retain),
1993                              ceph_cap_string(cap->mds_wanted),
1994                              ceph_cap_string(want));
1995                         delayed++;
1996                         continue;
1997                 }
1998 
1999 ack:
2000                 if (ci->i_ceph_flags & CEPH_I_NOFLUSH) {
2001                         dout(" skipping %p I_NOFLUSH set\n", inode);
2002                         continue;
2003                 }
2004 
2005                 if (session && session != cap->session) {
2006                         dout("oops, wrong session %p mutex\n", session);
2007                         mutex_unlock(&session->s_mutex);
2008                         session = NULL;
2009                 }
2010                 if (!session) {
2011                         session = cap->session;
2012                         if (mutex_trylock(&session->s_mutex) == 0) {
2013                                 dout("inverting session/ino locks on %p\n",
2014                                      session);
2015                                 spin_unlock(&ci->i_ceph_lock);
2016                                 if (took_snap_rwsem) {
2017                                         up_read(&mdsc->snap_rwsem);
2018                                         took_snap_rwsem = 0;
2019                                 }
2020                                 mutex_lock(&session->s_mutex);
2021                                 goto retry;
2022                         }
2023                 }
2024 
2025                 /* kick flushing and flush snaps before sending normal
2026                  * cap message */
2027                 if (cap == ci->i_auth_cap &&
2028                     (ci->i_ceph_flags &
2029                      (CEPH_I_KICK_FLUSH | CEPH_I_FLUSH_SNAPS))) {
2030                         if (ci->i_ceph_flags & CEPH_I_KICK_FLUSH) {
2031                                 __kick_flushing_caps(mdsc, session, ci, 0);
2032                                 ci->i_ceph_flags &= ~CEPH_I_KICK_FLUSH;
2033                         }
2034                         if (ci->i_ceph_flags & CEPH_I_FLUSH_SNAPS)
2035                                 __ceph_flush_snaps(ci, session);
2036 
2037                         goto retry_locked;
2038                 }
2039 
2040                 /* take snap_rwsem after session mutex */
2041                 if (!took_snap_rwsem) {
2042                         if (down_read_trylock(&mdsc->snap_rwsem) == 0) {
2043                                 dout("inverting snap/in locks on %p\n",
2044                                      inode);
2045                                 spin_unlock(&ci->i_ceph_lock);
2046                                 down_read(&mdsc->snap_rwsem);
2047                                 took_snap_rwsem = 1;
2048                                 goto retry;
2049                         }
2050                         took_snap_rwsem = 1;
2051                 }
2052 
2053                 if (cap == ci->i_auth_cap && ci->i_dirty_caps) {
2054                         flushing = __mark_caps_flushing(inode, session, false,
2055                                                         &flush_tid,
2056                                                         &oldest_flush_tid);
2057                 } else {
2058                         flushing = 0;
2059                         flush_tid = 0;
2060                         spin_lock(&mdsc->cap_dirty_lock);
2061                         oldest_flush_tid = __get_oldest_flush_tid(mdsc);
2062                         spin_unlock(&mdsc->cap_dirty_lock);
2063                 }
2064 
2065                 mds = cap->mds;  /* remember mds, so we don't repeat */
2066                 sent++;
2067 
2068                 /* __send_cap drops i_ceph_lock */
2069                 delayed += __send_cap(mdsc, cap, CEPH_CAP_OP_UPDATE, false,
2070                                 cap_used, want, retain, flushing,
2071                                 flush_tid, oldest_flush_tid);
2072                 goto retry; /* retake i_ceph_lock and restart our cap scan. */
2073         }
2074 
2075         /* Reschedule delayed caps release if we delayed anything */
2076         if (delayed)
2077                 __cap_delay_requeue(mdsc, ci, false);
2078 
2079         spin_unlock(&ci->i_ceph_lock);
2080 
2081         if (queue_invalidate)
2082                 ceph_queue_invalidate(inode);
2083 
2084         if (session)
2085                 mutex_unlock(&session->s_mutex);
2086         if (took_snap_rwsem)
2087                 up_read(&mdsc->snap_rwsem);
2088 }
2089 
2090 /*
2091  * Try to flush dirty caps back to the auth mds.
2092  */
2093 static int try_flush_caps(struct inode *inode, u64 *ptid)
2094 {
2095         struct ceph_mds_client *mdsc = ceph_sb_to_client(inode->i_sb)->mdsc;
2096         struct ceph_inode_info *ci = ceph_inode(inode);
2097         struct ceph_mds_session *session = NULL;
2098         int flushing = 0;
2099         u64 flush_tid = 0, oldest_flush_tid = 0;
2100 
2101 retry:
2102         spin_lock(&ci->i_ceph_lock);
2103         if (ci->i_ceph_flags & CEPH_I_NOFLUSH) {
2104                 spin_unlock(&ci->i_ceph_lock);
2105                 dout("try_flush_caps skipping %p I_NOFLUSH set\n", inode);
2106                 goto out;
2107         }
2108         if (ci->i_dirty_caps && ci->i_auth_cap) {
2109                 struct ceph_cap *cap = ci->i_auth_cap;
2110                 int used = __ceph_caps_used(ci);
2111                 int want = __ceph_caps_wanted(ci);
2112                 int delayed;
2113 
2114                 if (!session || session != cap->session) {
2115                         spin_unlock(&ci->i_ceph_lock);
2116                         if (session)
2117                                 mutex_unlock(&session->s_mutex);
2118                         session = cap->session;
2119                         mutex_lock(&session->s_mutex);
2120                         goto retry;
2121                 }
2122                 if (cap->session->s_state < CEPH_MDS_SESSION_OPEN) {
2123                         spin_unlock(&ci->i_ceph_lock);
2124                         goto out;
2125                 }
2126 
2127                 flushing = __mark_caps_flushing(inode, session, true,
2128                                                 &flush_tid, &oldest_flush_tid);
2129 
2130                 /* __send_cap drops i_ceph_lock */
2131                 delayed = __send_cap(mdsc, cap, CEPH_CAP_OP_FLUSH, true,
2132                                 used, want, (cap->issued | cap->implemented),
2133                                 flushing, flush_tid, oldest_flush_tid);
2134 
2135                 if (delayed) {
2136                         spin_lock(&ci->i_ceph_lock);
2137                         __cap_delay_requeue(mdsc, ci, true);
2138                         spin_unlock(&ci->i_ceph_lock);
2139                 }
2140         } else {
2141                 if (!list_empty(&ci->i_cap_flush_list)) {
2142                         struct ceph_cap_flush *cf =
2143                                 list_last_entry(&ci->i_cap_flush_list,
2144                                                 struct ceph_cap_flush, i_list);
2145                         cf->wake = true;
2146                         flush_tid = cf->tid;
2147                 }
2148                 flushing = ci->i_flushing_caps;
2149                 spin_unlock(&ci->i_ceph_lock);
2150         }
2151 out:
2152         if (session)
2153                 mutex_unlock(&session->s_mutex);
2154 
2155         *ptid = flush_tid;
2156         return flushing;
2157 }
2158 
2159 /*
2160  * Return true if we've flushed caps through the given flush_tid.
2161  */
2162 static int caps_are_flushed(struct inode *inode, u64 flush_tid)
2163 {
2164         struct ceph_inode_info *ci = ceph_inode(inode);
2165         int ret = 1;
2166 
2167         spin_lock(&ci->i_ceph_lock);
2168         if (!list_empty(&ci->i_cap_flush_list)) {
2169                 struct ceph_cap_flush * cf =
2170                         list_first_entry(&ci->i_cap_flush_list,
2171                                          struct ceph_cap_flush, i_list);
2172                 if (cf->tid <= flush_tid)
2173                         ret = 0;
2174         }
2175         spin_unlock(&ci->i_ceph_lock);
2176         return ret;
2177 }
2178 
2179 /*
2180  * wait for any unsafe requests to complete.
2181  */
2182 static int unsafe_request_wait(struct inode *inode)
2183 {
2184         struct ceph_inode_info *ci = ceph_inode(inode);
2185         struct ceph_mds_request *req1 = NULL, *req2 = NULL;
2186         int ret, err = 0;
2187 
2188         spin_lock(&ci->i_unsafe_lock);
2189         if (S_ISDIR(inode->i_mode) && !list_empty(&ci->i_unsafe_dirops)) {
2190                 req1 = list_last_entry(&ci->i_unsafe_dirops,
2191                                         struct ceph_mds_request,
2192                                         r_unsafe_dir_item);
2193                 ceph_mdsc_get_request(req1);
2194         }
2195         if (!list_empty(&ci->i_unsafe_iops)) {
2196                 req2 = list_last_entry(&ci->i_unsafe_iops,
2197                                         struct ceph_mds_request,
2198                                         r_unsafe_target_item);
2199                 ceph_mdsc_get_request(req2);
2200         }
2201         spin_unlock(&ci->i_unsafe_lock);
2202 
2203         dout("unsafe_request_wait %p wait on tid %llu %llu\n",
2204              inode, req1 ? req1->r_tid : 0ULL, req2 ? req2->r_tid : 0ULL);
2205         if (req1) {
2206                 ret = !wait_for_completion_timeout(&req1->r_safe_completion,
2207                                         ceph_timeout_jiffies(req1->r_timeout));
2208                 if (ret)
2209                         err = -EIO;
2210                 ceph_mdsc_put_request(req1);
2211         }
2212         if (req2) {
2213                 ret = !wait_for_completion_timeout(&req2->r_safe_completion,
2214                                         ceph_timeout_jiffies(req2->r_timeout));
2215                 if (ret)
2216                         err = -EIO;
2217                 ceph_mdsc_put_request(req2);
2218         }
2219         return err;
2220 }
2221 
2222 int ceph_fsync(struct file *file, loff_t start, loff_t end, int datasync)
2223 {
2224         struct inode *inode = file->f_mapping->host;
2225         struct ceph_inode_info *ci = ceph_inode(inode);
2226         u64 flush_tid;
2227         int ret;
2228         int dirty;
2229 
2230         dout("fsync %p%s\n", inode, datasync ? " datasync" : "");
2231 
2232         ret = file_write_and_wait_range(file, start, end);
2233         if (ret < 0)
2234                 goto out;
2235 
2236         if (datasync)
2237                 goto out;
2238 
2239         inode_lock(inode);
2240 
2241         dirty = try_flush_caps(inode, &flush_tid);
2242         dout("fsync dirty caps are %s\n", ceph_cap_string(dirty));
2243 
2244         ret = unsafe_request_wait(inode);
2245 
2246         /*
2247          * only wait on non-file metadata writeback (the mds
2248          * can recover size and mtime, so we don't need to
2249          * wait for that)
2250          */
2251         if (!ret && (dirty & ~CEPH_CAP_ANY_FILE_WR)) {
2252                 ret = wait_event_interruptible(ci->i_cap_wq,
2253                                         caps_are_flushed(inode, flush_tid));
2254         }
2255         inode_unlock(inode);
2256 out:
2257         dout("fsync %p%s result=%d\n", inode, datasync ? " datasync" : "", ret);
2258         return ret;
2259 }
2260 
2261 /*
2262  * Flush any dirty caps back to the mds.  If we aren't asked to wait,
2263  * queue inode for flush but don't do so immediately, because we can
2264  * get by with fewer MDS messages if we wait for data writeback to
2265  * complete first.
2266  */
2267 int ceph_write_inode(struct inode *inode, struct writeback_control *wbc)
2268 {
2269         struct ceph_inode_info *ci = ceph_inode(inode);
2270         u64 flush_tid;
2271         int err = 0;
2272         int dirty;
2273         int wait = (wbc->sync_mode == WB_SYNC_ALL && !wbc->for_sync);
2274 
2275         dout("write_inode %p wait=%d\n", inode, wait);
2276         if (wait) {
2277                 dirty = try_flush_caps(inode, &flush_tid);
2278                 if (dirty)
2279                         err = wait_event_interruptible(ci->i_cap_wq,
2280                                        caps_are_flushed(inode, flush_tid));
2281         } else {
2282                 struct ceph_mds_client *mdsc =
2283                         ceph_sb_to_client(inode->i_sb)->mdsc;
2284 
2285                 spin_lock(&ci->i_ceph_lock);
2286                 if (__ceph_caps_dirty(ci))
2287                         __cap_delay_requeue_front(mdsc, ci);
2288                 spin_unlock(&ci->i_ceph_lock);
2289         }
2290         return err;
2291 }
2292 
2293 static void __kick_flushing_caps(struct ceph_mds_client *mdsc,
2294                                  struct ceph_mds_session *session,
2295                                  struct ceph_inode_info *ci,
2296                                  u64 oldest_flush_tid)
2297         __releases(ci->i_ceph_lock)
2298         __acquires(ci->i_ceph_lock)
2299 {
2300         struct inode *inode = &ci->vfs_inode;
2301         struct ceph_cap *cap;
2302         struct ceph_cap_flush *cf;
2303         int ret;
2304         u64 first_tid = 0;
2305 
2306         list_for_each_entry(cf, &ci->i_cap_flush_list, i_list) {
2307                 if (cf->tid < first_tid)
2308                         continue;
2309 
2310                 cap = ci->i_auth_cap;
2311                 if (!(cap && cap->session == session)) {
2312                         pr_err("%p auth cap %p not mds%d ???\n",
2313                                inode, cap, session->s_mds);
2314                         break;
2315                 }
2316 
2317                 first_tid = cf->tid + 1;
2318 
2319                 if (cf->caps) {
2320                         dout("kick_flushing_caps %p cap %p tid %llu %s\n",
2321                              inode, cap, cf->tid, ceph_cap_string(cf->caps));
2322                         ci->i_ceph_flags |= CEPH_I_NODELAY;
2323                         ret = __send_cap(mdsc, cap, CEPH_CAP_OP_FLUSH,
2324                                           false, __ceph_caps_used(ci),
2325                                           __ceph_caps_wanted(ci),
2326                                           cap->issued | cap->implemented,
2327                                           cf->caps, cf->tid, oldest_flush_tid);
2328                         if (ret) {
2329                                 pr_err("kick_flushing_caps: error sending "
2330                                         "cap flush, ino (%llx.%llx) "
2331                                         "tid %llu flushing %s\n",
2332                                         ceph_vinop(inode), cf->tid,
2333                                         ceph_cap_string(cf->caps));
2334                         }
2335                 } else {
2336                         struct ceph_cap_snap *capsnap =
2337                                         container_of(cf, struct ceph_cap_snap,
2338                                                     cap_flush);
2339                         dout("kick_flushing_caps %p capsnap %p tid %llu %s\n",
2340                              inode, capsnap, cf->tid,
2341                              ceph_cap_string(capsnap->dirty));
2342 
2343                         refcount_inc(&capsnap->nref);
2344                         spin_unlock(&ci->i_ceph_lock);
2345 
2346                         ret = __send_flush_snap(inode, session, capsnap, cap->mseq,
2347                                                 oldest_flush_tid);
2348                         if (ret < 0) {
2349                                 pr_err("kick_flushing_caps: error sending "
2350                                         "cap flushsnap, ino (%llx.%llx) "
2351                                         "tid %llu follows %llu\n",
2352                                         ceph_vinop(inode), cf->tid,
2353                                         capsnap->follows);
2354                         }
2355 
2356                         ceph_put_cap_snap(capsnap);
2357                 }
2358 
2359                 spin_lock(&ci->i_ceph_lock);
2360         }
2361 }
2362 
2363 void ceph_early_kick_flushing_caps(struct ceph_mds_client *mdsc,
2364                                    struct ceph_mds_session *session)
2365 {
2366         struct ceph_inode_info *ci;
2367         struct ceph_cap *cap;
2368         u64 oldest_flush_tid;
2369 
2370         dout("early_kick_flushing_caps mds%d\n", session->s_mds);
2371 
2372         spin_lock(&mdsc->cap_dirty_lock);
2373         oldest_flush_tid = __get_oldest_flush_tid(mdsc);
2374         spin_unlock(&mdsc->cap_dirty_lock);
2375 
2376         list_for_each_entry(ci, &session->s_cap_flushing, i_flushing_item) {
2377                 spin_lock(&ci->i_ceph_lock);
2378                 cap = ci->i_auth_cap;
2379                 if (!(cap && cap->session == session)) {
2380                         pr_err("%p auth cap %p not mds%d ???\n",
2381                                 &ci->vfs_inode, cap, session->s_mds);
2382                         spin_unlock(&ci->i_ceph_lock);
2383                         continue;
2384                 }
2385 
2386 
2387                 /*
2388                  * if flushing caps were revoked, we re-send the cap flush
2389                  * in client reconnect stage. This guarantees MDS * processes
2390                  * the cap flush message before issuing the flushing caps to
2391                  * other client.
2392                  */
2393                 if ((cap->issued & ci->i_flushing_caps) !=
2394                     ci->i_flushing_caps) {
2395                         ci->i_ceph_flags &= ~CEPH_I_KICK_FLUSH;
2396                         __kick_flushing_caps(mdsc, session, ci,
2397                                              oldest_flush_tid);
2398                 } else {
2399                         ci->i_ceph_flags |= CEPH_I_KICK_FLUSH;
2400                 }
2401 
2402                 spin_unlock(&ci->i_ceph_lock);
2403         }
2404 }
2405 
2406 void ceph_kick_flushing_caps(struct ceph_mds_client *mdsc,
2407                              struct ceph_mds_session *session)
2408 {
2409         struct ceph_inode_info *ci;
2410         struct ceph_cap *cap;
2411         u64 oldest_flush_tid;
2412 
2413         dout("kick_flushing_caps mds%d\n", session->s_mds);
2414 
2415         spin_lock(&mdsc->cap_dirty_lock);
2416         oldest_flush_tid = __get_oldest_flush_tid(mdsc);
2417         spin_unlock(&mdsc->cap_dirty_lock);
2418 
2419         list_for_each_entry(ci, &session->s_cap_flushing, i_flushing_item) {
2420                 spin_lock(&ci->i_ceph_lock);
2421                 cap = ci->i_auth_cap;
2422                 if (!(cap && cap->session == session)) {
2423                         pr_err("%p auth cap %p not mds%d ???\n",
2424                                 &ci->vfs_inode, cap, session->s_mds);
2425                         spin_unlock(&ci->i_ceph_lock);
2426                         continue;
2427                 }
2428                 if (ci->i_ceph_flags & CEPH_I_KICK_FLUSH) {
2429                         ci->i_ceph_flags &= ~CEPH_I_KICK_FLUSH;
2430                         __kick_flushing_caps(mdsc, session, ci,
2431                                              oldest_flush_tid);
2432                 }
2433                 spin_unlock(&ci->i_ceph_lock);
2434         }
2435 }
2436 
2437 static void kick_flushing_inode_caps(struct ceph_mds_client *mdsc,
2438                                      struct ceph_mds_session *session,
2439                                      struct inode *inode)
2440         __releases(ci->i_ceph_lock)
2441 {
2442         struct ceph_inode_info *ci = ceph_inode(inode);
2443         struct ceph_cap *cap;
2444 
2445         cap = ci->i_auth_cap;
2446         dout("kick_flushing_inode_caps %p flushing %s\n", inode,
2447              ceph_cap_string(ci->i_flushing_caps));
2448 
2449         if (!list_empty(&ci->i_cap_flush_list)) {
2450                 u64 oldest_flush_tid;
2451                 spin_lock(&mdsc->cap_dirty_lock);
2452                 list_move_tail(&ci->i_flushing_item,
2453                                &cap->session->s_cap_flushing);
2454                 oldest_flush_tid = __get_oldest_flush_tid(mdsc);
2455                 spin_unlock(&mdsc->cap_dirty_lock);
2456 
2457                 ci->i_ceph_flags &= ~CEPH_I_KICK_FLUSH;
2458                 __kick_flushing_caps(mdsc, session, ci, oldest_flush_tid);
2459                 spin_unlock(&ci->i_ceph_lock);
2460         } else {
2461                 spin_unlock(&ci->i_ceph_lock);
2462         }
2463 }
2464 
2465 
2466 /*
2467  * Take references to capabilities we hold, so that we don't release
2468  * them to the MDS prematurely.
2469  *
2470  * Protected by i_ceph_lock.
2471  */
2472 static void __take_cap_refs(struct ceph_inode_info *ci, int got,
2473                             bool snap_rwsem_locked)
2474 {
2475         if (got & CEPH_CAP_PIN)
2476                 ci->i_pin_ref++;
2477         if (got & CEPH_CAP_FILE_RD)
2478                 ci->i_rd_ref++;
2479         if (got & CEPH_CAP_FILE_CACHE)
2480                 ci->i_rdcache_ref++;
2481         if (got & CEPH_CAP_FILE_WR) {
2482                 if (ci->i_wr_ref == 0 && !ci->i_head_snapc) {
2483                         BUG_ON(!snap_rwsem_locked);
2484                         ci->i_head_snapc = ceph_get_snap_context(
2485                                         ci->i_snap_realm->cached_context);
2486                 }
2487                 ci->i_wr_ref++;
2488         }
2489         if (got & CEPH_CAP_FILE_BUFFER) {
2490                 if (ci->i_wb_ref == 0)
2491                         ihold(&ci->vfs_inode);
2492                 ci->i_wb_ref++;
2493                 dout("__take_cap_refs %p wb %d -> %d (?)\n",
2494                      &ci->vfs_inode, ci->i_wb_ref-1, ci->i_wb_ref);
2495         }
2496 }
2497 
2498 /*
2499  * Try to grab cap references.  Specify those refs we @want, and the
2500  * minimal set we @need.  Also include the larger offset we are writing
2501  * to (when applicable), and check against max_size here as well.
2502  * Note that caller is responsible for ensuring max_size increases are
2503  * requested from the MDS.
2504  */
2505 static int try_get_cap_refs(struct ceph_inode_info *ci, int need, int want,
2506                             loff_t endoff, bool nonblock, int *got, int *err)
2507 {
2508         struct inode *inode = &ci->vfs_inode;
2509         struct ceph_mds_client *mdsc = ceph_inode_to_client(inode)->mdsc;
2510         int ret = 0;
2511         int have, implemented;
2512         int file_wanted;
2513         bool snap_rwsem_locked = false;
2514 
2515         dout("get_cap_refs %p need %s want %s\n", inode,
2516              ceph_cap_string(need), ceph_cap_string(want));
2517 
2518 again:
2519         spin_lock(&ci->i_ceph_lock);
2520 
2521         /* make sure file is actually open */
2522         file_wanted = __ceph_caps_file_wanted(ci);
2523         if ((file_wanted & need) != need) {
2524                 dout("try_get_cap_refs need %s file_wanted %s, EBADF\n",
2525                      ceph_cap_string(need), ceph_cap_string(file_wanted));
2526                 *err = -EBADF;
2527                 ret = 1;
2528                 goto out_unlock;
2529         }
2530 
2531         /* finish pending truncate */
2532         while (ci->i_truncate_pending) {
2533                 spin_unlock(&ci->i_ceph_lock);
2534                 if (snap_rwsem_locked) {
2535                         up_read(&mdsc->snap_rwsem);
2536                         snap_rwsem_locked = false;
2537                 }
2538                 __ceph_do_pending_vmtruncate(inode);
2539                 spin_lock(&ci->i_ceph_lock);
2540         }
2541 
2542         have = __ceph_caps_issued(ci, &implemented);
2543 
2544         if (have & need & CEPH_CAP_FILE_WR) {
2545                 if (endoff >= 0 && endoff > (loff_t)ci->i_max_size) {
2546                         dout("get_cap_refs %p endoff %llu > maxsize %llu\n",
2547                              inode, endoff, ci->i_max_size);
2548                         if (endoff > ci->i_requested_max_size) {
2549                                 *err = -EAGAIN;
2550                                 ret = 1;
2551                         }
2552                         goto out_unlock;
2553                 }
2554                 /*
2555                  * If a sync write is in progress, we must wait, so that we
2556                  * can get a final snapshot value for size+mtime.
2557                  */
2558                 if (__ceph_have_pending_cap_snap(ci)) {
2559                         dout("get_cap_refs %p cap_snap_pending\n", inode);
2560                         goto out_unlock;
2561                 }
2562         }
2563 
2564         if ((have & need) == need) {
2565                 /*
2566                  * Look at (implemented & ~have & not) so that we keep waiting
2567                  * on transition from wanted -> needed caps.  This is needed
2568                  * for WRBUFFER|WR -> WR to avoid a new WR sync write from
2569                  * going before a prior buffered writeback happens.
2570                  */
2571                 int not = want & ~(have & need);
2572                 int revoking = implemented & ~have;
2573                 dout("get_cap_refs %p have %s but not %s (revoking %s)\n",
2574                      inode, ceph_cap_string(have), ceph_cap_string(not),
2575                      ceph_cap_string(revoking));
2576                 if ((revoking & not) == 0) {
2577                         if (!snap_rwsem_locked &&
2578                             !ci->i_head_snapc &&
2579                             (need & CEPH_CAP_FILE_WR)) {
2580                                 if (!down_read_trylock(&mdsc->snap_rwsem)) {
2581                                         /*
2582                                          * we can not call down_read() when
2583                                          * task isn't in TASK_RUNNING state
2584                                          */
2585                                         if (nonblock) {
2586                                                 *err = -EAGAIN;
2587                                                 ret = 1;
2588                                                 goto out_unlock;
2589                                         }
2590 
2591                                         spin_unlock(&ci->i_ceph_lock);
2592                                         down_read(&mdsc->snap_rwsem);
2593                                         snap_rwsem_locked = true;
2594                                         goto again;
2595                                 }
2596                                 snap_rwsem_locked = true;
2597                         }
2598                         *got = need | (have & want);
2599                         if ((need & CEPH_CAP_FILE_RD) &&
2600                             !(*got & CEPH_CAP_FILE_CACHE))
2601                                 ceph_disable_fscache_readpage(ci);
2602                         __take_cap_refs(ci, *got, true);
2603                         ret = 1;
2604                 }
2605         } else {
2606                 int session_readonly = false;
2607                 if ((need & CEPH_CAP_FILE_WR) && ci->i_auth_cap) {
2608                         struct ceph_mds_session *s = ci->i_auth_cap->session;
2609                         spin_lock(&s->s_cap_lock);
2610                         session_readonly = s->s_readonly;
2611                         spin_unlock(&s->s_cap_lock);
2612                 }
2613                 if (session_readonly) {
2614                         dout("get_cap_refs %p needed %s but mds%d readonly\n",
2615                              inode, ceph_cap_string(need), ci->i_auth_cap->mds);
2616                         *err = -EROFS;
2617                         ret = 1;
2618                         goto out_unlock;
2619                 }
2620 
2621                 if (ci->i_ceph_flags & CEPH_I_CAP_DROPPED) {
2622                         int mds_wanted;
2623                         if (READ_ONCE(mdsc->fsc->mount_state) ==
2624                             CEPH_MOUNT_SHUTDOWN) {
2625                                 dout("get_cap_refs %p forced umount\n", inode);
2626                                 *err = -EIO;
2627                                 ret = 1;
2628                                 goto out_unlock;
2629                         }
2630                         mds_wanted = __ceph_caps_mds_wanted(ci, false);
2631                         if (need & ~(mds_wanted & need)) {
2632                                 dout("get_cap_refs %p caps were dropped"
2633                                      " (session killed?)\n", inode);
2634                                 *err = -ESTALE;
2635                                 ret = 1;
2636                                 goto out_unlock;
2637                         }
2638                         if (!(file_wanted & ~mds_wanted))
2639                                 ci->i_ceph_flags &= ~CEPH_I_CAP_DROPPED;
2640                 }
2641 
2642                 dout("get_cap_refs %p have %s needed %s\n", inode,
2643                      ceph_cap_string(have), ceph_cap_string(need));
2644         }
2645 out_unlock:
2646         spin_unlock(&ci->i_ceph_lock);
2647         if (snap_rwsem_locked)
2648                 up_read(&mdsc->snap_rwsem);
2649 
2650         dout("get_cap_refs %p ret %d got %s\n", inode,
2651              ret, ceph_cap_string(*got));
2652         return ret;
2653 }
2654 
2655 /*
2656  * Check the offset we are writing up to against our current
2657  * max_size.  If necessary, tell the MDS we want to write to
2658  * a larger offset.
2659  */
2660 static void check_max_size(struct inode *inode, loff_t endoff)
2661 {
2662         struct ceph_inode_info *ci = ceph_inode(inode);
2663         int check = 0;
2664 
2665         /* do we need to explicitly request a larger max_size? */
2666         spin_lock(&ci->i_ceph_lock);
2667         if (endoff >= ci->i_max_size && endoff > ci->i_wanted_max_size) {
2668                 dout("write %p at large endoff %llu, req max_size\n",
2669                      inode, endoff);
2670                 ci->i_wanted_max_size = endoff;
2671         }
2672         /* duplicate ceph_check_caps()'s logic */
2673         if (ci->i_auth_cap &&
2674             (ci->i_auth_cap->issued & CEPH_CAP_FILE_WR) &&
2675             ci->i_wanted_max_size > ci->i_max_size &&
2676             ci->i_wanted_max_size > ci->i_requested_max_size)
2677                 check = 1;
2678         spin_unlock(&ci->i_ceph_lock);
2679         if (check)
2680                 ceph_check_caps(ci, CHECK_CAPS_AUTHONLY, NULL);
2681 }
2682 
2683 int ceph_try_get_caps(struct ceph_inode_info *ci, int need, int want,
2684                       bool nonblock, int *got)
2685 {
2686         int ret, err = 0;
2687 
2688         BUG_ON(need & ~CEPH_CAP_FILE_RD);
2689         BUG_ON(want & ~(CEPH_CAP_FILE_CACHE|CEPH_CAP_FILE_LAZYIO|CEPH_CAP_FILE_SHARED));
2690         ret = ceph_pool_perm_check(ci, need);
2691         if (ret < 0)
2692                 return ret;
2693 
2694         ret = try_get_cap_refs(ci, need, want, 0, nonblock, got, &err);
2695         if (ret) {
2696                 if (err == -EAGAIN) {
2697                         ret = 0;
2698                 } else if (err < 0) {
2699                         ret = err;
2700                 }
2701         }
2702         return ret;
2703 }
2704 
2705 /*
2706  * Wait for caps, and take cap references.  If we can't get a WR cap
2707  * due to a small max_size, make sure we check_max_size (and possibly
2708  * ask the mds) so we don't get hung up indefinitely.
2709  */
2710 int ceph_get_caps(struct ceph_inode_info *ci, int need, int want,
2711                   loff_t endoff, int *got, struct page **pinned_page)
2712 {
2713         int _got, ret, err = 0;
2714 
2715         ret = ceph_pool_perm_check(ci, need);
2716         if (ret < 0)
2717                 return ret;
2718 
2719         while (true) {
2720                 if (endoff > 0)
2721                         check_max_size(&ci->vfs_inode, endoff);
2722 
2723                 err = 0;
2724                 _got = 0;
2725                 ret = try_get_cap_refs(ci, need, want, endoff,
2726                                        false, &_got, &err);
2727                 if (ret) {
2728                         if (err == -EAGAIN)
2729                                 continue;
2730                         if (err < 0)
2731                                 ret = err;
2732                 } else {
2733                         DEFINE_WAIT_FUNC(wait, woken_wake_function);
2734                         add_wait_queue(&ci->i_cap_wq, &wait);
2735 
2736                         while (!try_get_cap_refs(ci, need, want, endoff,
2737                                                  true, &_got, &err)) {
2738                                 if (signal_pending(current)) {
2739                                         ret = -ERESTARTSYS;
2740                                         break;
2741                                 }
2742                                 wait_woken(&wait, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
2743                         }
2744 
2745                         remove_wait_queue(&ci->i_cap_wq, &wait);
2746 
2747                         if (err == -EAGAIN)
2748                                 continue;
2749                         if (err < 0)
2750                                 ret = err;
2751                 }
2752                 if (ret < 0) {
2753                         if (err == -ESTALE) {
2754                                 /* session was killed, try renew caps */
2755                                 ret = ceph_renew_caps(&ci->vfs_inode);
2756                                 if (ret == 0)
2757                                         continue;
2758                         }
2759                         return ret;
2760                 }
2761 
2762                 if (ci->i_inline_version != CEPH_INLINE_NONE &&
2763                     (_got & (CEPH_CAP_FILE_CACHE|CEPH_CAP_FILE_LAZYIO)) &&
2764                     i_size_read(&ci->vfs_inode) > 0) {
2765                         struct page *page =
2766                                 find_get_page(ci->vfs_inode.i_mapping, 0);
2767                         if (page) {
2768                                 if (PageUptodate(page)) {
2769                                         *pinned_page = page;
2770                                         break;
2771                                 }
2772                                 put_page(page);
2773                         }
2774                         /*
2775                          * drop cap refs first because getattr while
2776                          * holding * caps refs can cause deadlock.
2777                          */
2778                         ceph_put_cap_refs(ci, _got);
2779                         _got = 0;
2780 
2781                         /*
2782                          * getattr request will bring inline data into
2783                          * page cache
2784                          */
2785                         ret = __ceph_do_getattr(&ci->vfs_inode, NULL,
2786                                                 CEPH_STAT_CAP_INLINE_DATA,
2787                                                 true);
2788                         if (ret < 0)
2789                                 return ret;
2790                         continue;
2791                 }
2792                 break;
2793         }
2794 
2795         if ((_got & CEPH_CAP_FILE_RD) && (_got & CEPH_CAP_FILE_CACHE))
2796                 ceph_fscache_revalidate_cookie(ci);
2797 
2798         *got = _got;
2799         return 0;
2800 }
2801 
2802 /*
2803  * Take cap refs.  Caller must already know we hold at least one ref
2804  * on the caps in question or we don't know this is safe.
2805  */
2806 void ceph_get_cap_refs(struct ceph_inode_info *ci, int caps)
2807 {
2808         spin_lock(&ci->i_ceph_lock);
2809         __take_cap_refs(ci, caps, false);
2810         spin_unlock(&ci->i_ceph_lock);
2811 }
2812 
2813 
2814 /*
2815  * drop cap_snap that is not associated with any snapshot.
2816  * we don't need to send FLUSHSNAP message for it.
2817  */
2818 static int ceph_try_drop_cap_snap(struct ceph_inode_info *ci,
2819                                   struct ceph_cap_snap *capsnap)
2820 {
2821         if (!capsnap->need_flush &&
2822             !capsnap->writing && !capsnap->dirty_pages) {
2823                 dout("dropping cap_snap %p follows %llu\n",
2824                      capsnap, capsnap->follows);
2825                 BUG_ON(capsnap->cap_flush.tid > 0);
2826                 ceph_put_snap_context(capsnap->context);
2827                 if (!list_is_last(&capsnap->ci_item, &ci->i_cap_snaps))
2828                         ci->i_ceph_flags |= CEPH_I_FLUSH_SNAPS;
2829 
2830                 list_del(&capsnap->ci_item);
2831                 ceph_put_cap_snap(capsnap);
2832                 return 1;
2833         }
2834         return 0;
2835 }
2836 
2837 /*
2838  * Release cap refs.
2839  *
2840  * If we released the last ref on any given cap, call ceph_check_caps
2841  * to release (or schedule a release).
2842  *
2843  * If we are releasing a WR cap (from a sync write), finalize any affected
2844  * cap_snap, and wake up any waiters.
2845  */
2846 void ceph_put_cap_refs(struct ceph_inode_info *ci, int had)
2847 {
2848         struct inode *inode = &ci->vfs_inode;
2849         int last = 0, put = 0, flushsnaps = 0, wake = 0;
2850 
2851         spin_lock(&ci->i_ceph_lock);
2852         if (had & CEPH_CAP_PIN)
2853                 --ci->i_pin_ref;
2854         if (had & CEPH_CAP_FILE_RD)
2855                 if (--ci->i_rd_ref == 0)
2856                         last++;
2857         if (had & CEPH_CAP_FILE_CACHE)
2858                 if (--ci->i_rdcache_ref == 0)
2859                         last++;
2860         if (had & CEPH_CAP_FILE_BUFFER) {
2861                 if (--ci->i_wb_ref == 0) {
2862                         last++;
2863                         put++;
2864                 }
2865                 dout("put_cap_refs %p wb %d -> %d (?)\n",
2866                      inode, ci->i_wb_ref+1, ci->i_wb_ref);
2867         }
2868         if (had & CEPH_CAP_FILE_WR)
2869                 if (--ci->i_wr_ref == 0) {
2870                         last++;
2871                         if (__ceph_have_pending_cap_snap(ci)) {
2872                                 struct ceph_cap_snap *capsnap =
2873                                         list_last_entry(&ci->i_cap_snaps,
2874                                                         struct ceph_cap_snap,
2875                                                         ci_item);
2876                                 capsnap->writing = 0;
2877                                 if (ceph_try_drop_cap_snap(ci, capsnap))
2878                                         put++;
2879                                 else if (__ceph_finish_cap_snap(ci, capsnap))
2880                                         flushsnaps = 1;
2881                                 wake = 1;
2882                         }
2883                         if (ci->i_wrbuffer_ref_head == 0 &&
2884                             ci->i_dirty_caps == 0 &&
2885                             ci->i_flushing_caps == 0) {
2886                                 BUG_ON(!ci->i_head_snapc);
2887                                 ceph_put_snap_context(ci->i_head_snapc);
2888                                 ci->i_head_snapc = NULL;
2889                         }
2890                         /* see comment in __ceph_remove_cap() */
2891                         if (!__ceph_is_any_caps(ci) && ci->i_snap_realm)
2892                                 drop_inode_snap_realm(ci);
2893                 }
2894         spin_unlock(&ci->i_ceph_lock);
2895 
2896         dout("put_cap_refs %p had %s%s%s\n", inode, ceph_cap_string(had),
2897              last ? " last" : "", put ? " put" : "");
2898 
2899         if (last && !flushsnaps)
2900                 ceph_check_caps(ci, 0, NULL);
2901         else if (flushsnaps)
2902                 ceph_flush_snaps(ci, NULL);
2903         if (wake)
2904                 wake_up_all(&ci->i_cap_wq);
2905         while (put-- > 0)
2906                 iput(inode);
2907 }
2908 
2909 /*
2910  * Release @nr WRBUFFER refs on dirty pages for the given @snapc snap
2911  * context.  Adjust per-snap dirty page accounting as appropriate.
2912  * Once all dirty data for a cap_snap is flushed, flush snapped file
2913  * metadata back to the MDS.  If we dropped the last ref, call
2914  * ceph_check_caps.
2915  */
2916 void ceph_put_wrbuffer_cap_refs(struct ceph_inode_info *ci, int nr,
2917                                 struct ceph_snap_context *snapc)
2918 {
2919         struct inode *inode = &ci->vfs_inode;
2920         struct ceph_cap_snap *capsnap = NULL;
2921         int put = 0;
2922         bool last = false;
2923         bool found = false;
2924         bool flush_snaps = false;
2925         bool complete_capsnap = false;
2926 
2927         spin_lock(&ci->i_ceph_lock);
2928         ci->i_wrbuffer_ref -= nr;
2929         if (ci->i_wrbuffer_ref == 0) {
2930                 last = true;
2931                 put++;
2932         }
2933 
2934         if (ci->i_head_snapc == snapc) {
2935                 ci->i_wrbuffer_ref_head -= nr;
2936                 if (ci->i_wrbuffer_ref_head == 0 &&
2937                     ci->i_wr_ref == 0 &&
2938                     ci->i_dirty_caps == 0 &&
2939                     ci->i_flushing_caps == 0) {
2940                         BUG_ON(!ci->i_head_snapc);
2941                         ceph_put_snap_context(ci->i_head_snapc);
2942                         ci->i_head_snapc = NULL;
2943                 }
2944                 dout("put_wrbuffer_cap_refs on %p head %d/%d -> %d/%d %s\n",
2945                      inode,
2946                      ci->i_wrbuffer_ref+nr, ci->i_wrbuffer_ref_head+nr,
2947                      ci->i_wrbuffer_ref, ci->i_wrbuffer_ref_head,
2948                      last ? " LAST" : "");
2949         } else {
2950                 list_for_each_entry(capsnap, &ci->i_cap_snaps, ci_item) {
2951                         if (capsnap->context == snapc) {
2952                                 found = true;
2953                                 break;
2954                         }
2955                 }
2956                 BUG_ON(!found);
2957                 capsnap->dirty_pages -= nr;
2958                 if (capsnap->dirty_pages == 0) {
2959                         complete_capsnap = true;
2960                         if (!capsnap->writing) {
2961                                 if (ceph_try_drop_cap_snap(ci, capsnap)) {
2962                                         put++;
2963                                 } else {
2964                                         ci->i_ceph_flags |= CEPH_I_FLUSH_SNAPS;
2965                                         flush_snaps = true;
2966                                 }
2967                         }
2968                 }
2969                 dout("put_wrbuffer_cap_refs on %p cap_snap %p "
2970                      " snap %lld %d/%d -> %d/%d %s%s\n",
2971                      inode, capsnap, capsnap->context->seq,
2972                      ci->i_wrbuffer_ref+nr, capsnap->dirty_pages + nr,
2973                      ci->i_wrbuffer_ref, capsnap->dirty_pages,
2974                      last ? " (wrbuffer last)" : "",
2975                      complete_capsnap ? " (complete capsnap)" : "");
2976         }
2977 
2978         spin_unlock(&ci->i_ceph_lock);
2979 
2980         if (last) {
2981                 ceph_check_caps(ci, CHECK_CAPS_AUTHONLY, NULL);
2982         } else if (flush_snaps) {
2983                 ceph_flush_snaps(ci, NULL);
2984         }
2985         if (complete_capsnap)
2986                 wake_up_all(&ci->i_cap_wq);
2987         while (put-- > 0)
2988                 iput(inode);
2989 }
2990 
2991 /*
2992  * Invalidate unlinked inode's aliases, so we can drop the inode ASAP.
2993  */
2994 static void invalidate_aliases(struct inode *inode)
2995 {
2996         struct dentry *dn, *prev = NULL;
2997 
2998         dout("invalidate_aliases inode %p\n", inode);
2999         d_prune_aliases(inode);
3000         /*
3001          * For non-directory inode, d_find_alias() only returns
3002          * hashed dentry. After calling d_invalidate(), the
3003          * dentry becomes unhashed.
3004          *
3005          * For directory inode, d_find_alias() can return
3006          * unhashed dentry. But directory inode should have
3007          * one alias at most.
3008          */
3009         while ((dn = d_find_alias(inode))) {
3010                 if (dn == prev) {
3011                         dput(dn);
3012                         break;
3013                 }
3014                 d_invalidate(dn);
3015                 if (prev)
3016                         dput(prev);
3017                 prev = dn;
3018         }
3019         if (prev)
3020                 dput(prev);
3021 }
3022 
3023 struct cap_extra_info {
3024         struct ceph_string *pool_ns;
3025         /* inline data */
3026         u64 inline_version;
3027         void *inline_data;
3028         u32 inline_len;
3029         /* dirstat */
3030         bool dirstat_valid;
3031         u64 nfiles;
3032         u64 nsubdirs;
3033         /* currently issued */
3034         int issued;
3035 };
3036 
3037 /*
3038  * Handle a cap GRANT message from the MDS.  (Note that a GRANT may
3039  * actually be a revocation if it specifies a smaller cap set.)
3040  *
3041  * caller holds s_mutex and i_ceph_lock, we drop both.
3042  */
3043 static void handle_cap_grant(struct inode *inode,
3044                              struct ceph_mds_session *session,
3045                              struct ceph_cap *cap,
3046                              struct ceph_mds_caps *grant,
3047                              struct ceph_buffer *xattr_buf,
3048                              struct cap_extra_info *extra_info)
3049         __releases(ci->i_ceph_lock)
3050         __releases(session->s_mdsc->snap_rwsem)
3051 {
3052         struct ceph_inode_info *ci = ceph_inode(inode);
3053         int seq = le32_to_cpu(grant->seq);
3054         int newcaps = le32_to_cpu(grant->caps);
3055         int used, wanted, dirty;
3056         u64 size = le64_to_cpu(grant->size);
3057         u64 max_size = le64_to_cpu(grant->max_size);
3058         unsigned char check_caps = 0;
3059         bool was_stale = cap->cap_gen < session->s_cap_gen;
3060         bool wake = false;
3061         bool writeback = false;
3062         bool queue_trunc = false;
3063         bool queue_invalidate = false;
3064         bool deleted_inode = false;
3065         bool fill_inline = false;
3066 
3067         dout("handle_cap_grant inode %p cap %p mds%d seq %d %s\n",
3068              inode, cap, session->s_mds, seq, ceph_cap_string(newcaps));
3069         dout(" size %llu max_size %llu, i_size %llu\n", size, max_size,
3070                 inode->i_size);
3071 
3072 
3073         /*
3074          * If CACHE is being revoked, and we have no dirty buffers,
3075          * try to invalidate (once).  (If there are dirty buffers, we
3076          * will invalidate _after_ writeback.)
3077          */
3078         if (!S_ISDIR(inode->i_mode) && /* don't invalidate readdir cache */
3079             ((cap->issued & ~newcaps) & CEPH_CAP_FILE_CACHE) &&
3080             (newcaps & CEPH_CAP_FILE_LAZYIO) == 0 &&
3081             !(ci->i_wrbuffer_ref || ci->i_wb_ref)) {
3082                 if (try_nonblocking_invalidate(inode)) {
3083                         /* there were locked pages.. invalidate later
3084                            in a separate thread. */
3085                         if (ci->i_rdcache_revoking != ci->i_rdcache_gen) {
3086                                 queue_invalidate = true;
3087                                 ci->i_rdcache_revoking = ci->i_rdcache_gen;
3088                         }
3089                 }
3090         }
3091 
3092         if (was_stale)
3093                 cap->issued = cap->implemented = CEPH_CAP_PIN;
3094 
3095         /*
3096          * auth mds of the inode changed. we received the cap export message,
3097          * but still haven't received the cap import message. handle_cap_export
3098          * updated the new auth MDS' cap.
3099          *
3100          * "ceph_seq_cmp(seq, cap->seq) <= 0" means we are processing a message
3101          * that was sent before the cap import message. So don't remove caps.
3102          */
3103         if (ceph_seq_cmp(seq, cap->seq) <= 0) {
3104                 WARN_ON(cap != ci->i_auth_cap);
3105                 WARN_ON(cap->cap_id != le64_to_cpu(grant->cap_id));
3106                 seq = cap->seq;
3107                 newcaps |= cap->issued;
3108         }
3109 
3110         /* side effects now are allowed */
3111         cap->cap_gen = session->s_cap_gen;
3112         cap->seq = seq;
3113 
3114         __check_cap_issue(ci, cap, newcaps);
3115 
3116         if ((newcaps & CEPH_CAP_AUTH_SHARED) &&
3117             (extra_info->issued & CEPH_CAP_AUTH_EXCL) == 0) {
3118                 inode->i_mode = le32_to_cpu(grant->mode);
3119                 inode->i_uid = make_kuid(&init_user_ns, le32_to_cpu(grant->uid));
3120                 inode->i_gid = make_kgid(&init_user_ns, le32_to_cpu(grant->gid));
3121                 dout("%p mode 0%o uid.gid %d.%d\n", inode, inode->i_mode,
3122                      from_kuid(&init_user_ns, inode->i_uid),
3123                      from_kgid(&init_user_ns, inode->i_gid));
3124         }
3125 
3126         if ((newcaps & CEPH_CAP_LINK_SHARED) &&
3127             (extra_info->issued & CEPH_CAP_LINK_EXCL) == 0) {
3128                 set_nlink(inode, le32_to_cpu(grant->nlink));
3129                 if (inode->i_nlink == 0 &&
3130                     (newcaps & (CEPH_CAP_LINK_SHARED | CEPH_CAP_LINK_EXCL)))
3131                         deleted_inode = true;
3132         }
3133 
3134         if ((extra_info->issued & CEPH_CAP_XATTR_EXCL) == 0 &&
3135             grant->xattr_len) {
3136                 int len = le32_to_cpu(grant->xattr_len);
3137                 u64 version = le64_to_cpu(grant->xattr_version);
3138 
3139                 if (version > ci->i_xattrs.version) {
3140                         dout(" got new xattrs v%llu on %p len %d\n",
3141                              version, inode, len);
3142                         if (ci->i_xattrs.blob)
3143                                 ceph_buffer_put(ci->i_xattrs.blob);
3144                         ci->i_xattrs.blob = ceph_buffer_get(xattr_buf);
3145                         ci->i_xattrs.version = version;
3146                         ceph_forget_all_cached_acls(inode);
3147                 }
3148         }
3149 
3150         if (newcaps & CEPH_CAP_ANY_RD) {
3151                 struct timespec64 mtime, atime, ctime;
3152                 /* ctime/mtime/atime? */
3153                 ceph_decode_timespec64(&mtime, &grant->mtime);
3154                 ceph_decode_timespec64(&atime, &grant->atime);
3155                 ceph_decode_timespec64(&ctime, &grant->ctime);
3156                 ceph_fill_file_time(inode, extra_info->issued,
3157                                     le32_to_cpu(grant->time_warp_seq),
3158                                     &ctime, &mtime, &atime);
3159         }
3160 
3161         if ((newcaps & CEPH_CAP_FILE_SHARED) && extra_info->dirstat_valid) {
3162                 ci->i_files = extra_info->nfiles;
3163                 ci->i_subdirs = extra_info->nsubdirs;
3164         }
3165 
3166         if (newcaps & (CEPH_CAP_ANY_FILE_RD | CEPH_CAP_ANY_FILE_WR)) {
3167                 /* file layout may have changed */
3168                 s64 old_pool = ci->i_layout.pool_id;
3169                 struct ceph_string *old_ns;
3170 
3171                 ceph_file_layout_from_legacy(&ci->i_layout, &grant->layout);
3172                 old_ns = rcu_dereference_protected(ci->i_layout.pool_ns,
3173                                         lockdep_is_held(&ci->i_ceph_lock));
3174                 rcu_assign_pointer(ci->i_layout.pool_ns, extra_info->pool_ns);
3175 
3176                 if (ci->i_layout.pool_id != old_pool ||
3177                     extra_info->pool_ns != old_ns)
3178                         ci->i_ceph_flags &= ~CEPH_I_POOL_PERM;
3179 
3180                 extra_info->pool_ns = old_ns;
3181 
3182                 /* size/truncate_seq? */
3183                 queue_trunc = ceph_fill_file_size(inode, extra_info->issued,
3184                                         le32_to_cpu(grant->truncate_seq),
3185                                         le64_to_cpu(grant->truncate_size),
3186                                         size);
3187         }
3188 
3189         if (ci->i_auth_cap == cap && (newcaps & CEPH_CAP_ANY_FILE_WR)) {
3190                 if (max_size != ci->i_max_size) {
3191                         dout("max_size %lld -> %llu\n",
3192                              ci->i_max_size, max_size);
3193                         ci->i_max_size = max_size;
3194                         if (max_size >= ci->i_wanted_max_size) {
3195                                 ci->i_wanted_max_size = 0;  /* reset */
3196                                 ci->i_requested_max_size = 0;
3197                         }
3198                         wake = true;
3199                 } else if (ci->i_wanted_max_size > ci->i_max_size &&
3200                            ci->i_wanted_max_size > ci->i_requested_max_size) {
3201                         /* CEPH_CAP_OP_IMPORT */
3202                         wake = true;
3203                 }
3204         }
3205 
3206         /* check cap bits */
3207         wanted = __ceph_caps_wanted(ci);
3208         used = __ceph_caps_used(ci);
3209         dirty = __ceph_caps_dirty(ci);
3210         dout(" my wanted = %s, used = %s, dirty %s\n",
3211              ceph_cap_string(wanted),
3212              ceph_cap_string(used),
3213              ceph_cap_string(dirty));
3214 
3215         if ((was_stale || le32_to_cpu(grant->op) == CEPH_CAP_OP_IMPORT) &&
3216             (wanted & ~(cap->mds_wanted | newcaps))) {
3217                 /*
3218                  * If mds is importing cap, prior cap messages that update
3219                  * 'wanted' may get dropped by mds (migrate seq mismatch).
3220                  *
3221                  * We don't send cap message to update 'wanted' if what we
3222                  * want are already issued. If mds revokes caps, cap message
3223                  * that releases caps also tells mds what we want. But if
3224                  * caps got revoked by mds forcedly (session stale). We may
3225                  * haven't told mds what we want.
3226                  */
3227                 check_caps = 1;
3228         }
3229 
3230         /* revocation, grant, or no-op? */
3231         if (cap->issued & ~newcaps) {
3232                 int revoking = cap->issued & ~newcaps;
3233 
3234                 dout("revocation: %s -> %s (revoking %s)\n",
3235                      ceph_cap_string(cap->issued),
3236                      ceph_cap_string(newcaps),
3237                      ceph_cap_string(revoking));
3238                 if (revoking & used & CEPH_CAP_FILE_BUFFER)
3239                         writeback = true;  /* initiate writeback; will delay ack */
3240                 else if (revoking == CEPH_CAP_FILE_CACHE &&
3241                          (newcaps & CEPH_CAP_FILE_LAZYIO) == 0 &&
3242                          queue_invalidate)
3243                         ; /* do nothing yet, invalidation will be queued */
3244                 else if (cap == ci->i_auth_cap)
3245                         check_caps = 1; /* check auth cap only */
3246                 else
3247                         check_caps = 2; /* check all caps */
3248                 cap->issued = newcaps;
3249                 cap->implemented |= newcaps;
3250         } else if (cap->issued == newcaps) {
3251                 dout("caps unchanged: %s -> %s\n",
3252                      ceph_cap_string(cap->issued), ceph_cap_string(newcaps));
3253         } else {
3254                 dout("grant: %s -> %s\n", ceph_cap_string(cap->issued),
3255                      ceph_cap_string(newcaps));
3256                 /* non-auth MDS is revoking the newly grant caps ? */
3257                 if (cap == ci->i_auth_cap &&
3258                     __ceph_caps_revoking_other(ci, cap, newcaps))
3259                     check_caps = 2;
3260 
3261                 cap->issued = newcaps;
3262                 cap->implemented |= newcaps; /* add bits only, to
3263                                               * avoid stepping on a
3264                                               * pending revocation */
3265                 wake = true;
3266         }
3267         BUG_ON(cap->issued & ~cap->implemented);
3268 
3269         if (extra_info->inline_version > 0 &&
3270             extra_info->inline_version >= ci->i_inline_version) {
3271                 ci->i_inline_version = extra_info->inline_version;
3272                 if (ci->i_inline_version != CEPH_INLINE_NONE &&
3273                     (newcaps & (CEPH_CAP_FILE_CACHE|CEPH_CAP_FILE_LAZYIO)))
3274                         fill_inline = true;
3275         }
3276 
3277         if (le32_to_cpu(grant->op) == CEPH_CAP_OP_IMPORT) {
3278                 if (newcaps & ~extra_info->issued)
3279                         wake = true;
3280                 kick_flushing_inode_caps(session->s_mdsc, session, inode);
3281                 up_read(&session->s_mdsc->snap_rwsem);
3282         } else {
3283                 spin_unlock(&ci->i_ceph_lock);
3284         }
3285 
3286         if (fill_inline)
3287                 ceph_fill_inline_data(inode, NULL, extra_info->inline_data,
3288                                       extra_info->inline_len);
3289 
3290         if (queue_trunc)
3291                 ceph_queue_vmtruncate(inode);
3292 
3293         if (writeback)
3294                 /*
3295                  * queue inode for writeback: we can't actually call
3296                  * filemap_write_and_wait, etc. from message handler
3297                  * context.
3298                  */
3299                 ceph_queue_writeback(inode);
3300         if (queue_invalidate)
3301                 ceph_queue_invalidate(inode);
3302         if (deleted_inode)
3303                 invalidate_aliases(inode);
3304         if (wake)
3305                 wake_up_all(&ci->i_cap_wq);
3306 
3307         if (check_caps == 1)
3308                 ceph_check_caps(ci, CHECK_CAPS_NODELAY|CHECK_CAPS_AUTHONLY,
3309                                 session);
3310         else if (check_caps == 2)
3311                 ceph_check_caps(ci, CHECK_CAPS_NODELAY, session);
3312         else
3313                 mutex_unlock(&session->s_mutex);
3314 }
3315 
3316 /*
3317  * Handle FLUSH_ACK from MDS, indicating that metadata we sent to the
3318  * MDS has been safely committed.
3319  */
3320 static void handle_cap_flush_ack(struct inode *inode, u64 flush_tid,
3321                                  struct ceph_mds_caps *m,
3322                                  struct ceph_mds_session *session,
3323                                  struct ceph_cap *cap)
3324         __releases(ci->i_ceph_lock)
3325 {
3326         struct ceph_inode_info *ci = ceph_inode(inode);
3327         struct ceph_mds_client *mdsc = ceph_sb_to_client(inode->i_sb)->mdsc;
3328         struct ceph_cap_flush *cf, *tmp_cf;
3329         LIST_HEAD(to_remove);
3330         unsigned seq = le32_to_cpu(m->seq);
3331         int dirty = le32_to_cpu(m->dirty);
3332         int cleaned = 0;
3333         bool drop = false;
3334         bool wake_ci = false;
3335         bool wake_mdsc = false;
3336 
3337         list_for_each_entry_safe(cf, tmp_cf, &ci->i_cap_flush_list, i_list) {
3338                 if (cf->tid == flush_tid)
3339                         cleaned = cf->caps;
3340                 if (cf->caps == 0) /* capsnap */
3341                         continue;
3342                 if (cf->tid <= flush_tid) {
3343                         if (__finish_cap_flush(NULL, ci, cf))
3344                                 wake_ci = true;
3345                         list_add_tail(&cf->i_list, &to_remove);
3346                 } else {
3347                         cleaned &= ~cf->caps;
3348                         if (!cleaned)
3349                                 break;
3350                 }
3351         }
3352 
3353         dout("handle_cap_flush_ack inode %p mds%d seq %d on %s cleaned %s,"
3354              " flushing %s -> %s\n",
3355              inode, session->s_mds, seq, ceph_cap_string(dirty),
3356              ceph_cap_string(cleaned), ceph_cap_string(ci->i_flushing_caps),
3357              ceph_cap_string(ci->i_flushing_caps & ~cleaned));
3358 
3359         if (list_empty(&to_remove) && !cleaned)
3360                 goto out;
3361 
3362         ci->i_flushing_caps &= ~cleaned;
3363 
3364         spin_lock(&mdsc->cap_dirty_lock);
3365 
3366         list_for_each_entry(cf, &to_remove, i_list) {
3367                 if (__finish_cap_flush(mdsc, NULL, cf))
3368                         wake_mdsc = true;
3369         }
3370 
3371         if (ci->i_flushing_caps == 0) {
3372                 if (list_empty(&ci->i_cap_flush_list)) {
3373                         list_del_init(&ci->i_flushing_item);
3374                         if (!list_empty(&session->s_cap_flushing)) {
3375                                 dout(" mds%d still flushing cap on %p\n",
3376                                      session->s_mds,
3377                                      &list_first_entry(&session->s_cap_flushing,
3378                                                 struct ceph_inode_info,
3379                                                 i_flushing_item)->vfs_inode);
3380                         }
3381                 }
3382                 mdsc->num_cap_flushing--;
3383                 dout(" inode %p now !flushing\n", inode);
3384 
3385                 if (ci->i_dirty_caps == 0) {
3386                         dout(" inode %p now clean\n", inode);
3387                         BUG_ON(!list_empty(&ci->i_dirty_item));
3388                         drop = true;
3389                         if (ci->i_wr_ref == 0 &&
3390                             ci->i_wrbuffer_ref_head == 0) {
3391                                 BUG_ON(!ci->i_head_snapc);
3392                                 ceph_put_snap_context(ci->i_head_snapc);
3393                                 ci->i_head_snapc = NULL;
3394                         }
3395                 } else {
3396                         BUG_ON(list_empty(&ci->i_dirty_item));
3397                 }
3398         }
3399         spin_unlock(&mdsc->cap_dirty_lock);
3400 
3401 out:
3402         spin_unlock(&ci->i_ceph_lock);
3403 
3404         while (!list_empty(&to_remove)) {
3405                 cf = list_first_entry(&to_remove,
3406                                       struct ceph_cap_flush, i_list);
3407                 list_del(&cf->i_list);
3408                 ceph_free_cap_flush(cf);
3409         }
3410 
3411         if (wake_ci)
3412                 wake_up_all(&ci->i_cap_wq);
3413         if (wake_mdsc)
3414                 wake_up_all(&mdsc->cap_flushing_wq);
3415         if (drop)
3416                 iput(inode);
3417 }
3418 
3419 /*
3420  * Handle FLUSHSNAP_ACK.  MDS has flushed snap data to disk and we can
3421  * throw away our cap_snap.
3422  *
3423  * Caller hold s_mutex.
3424  */
3425 static void handle_cap_flushsnap_ack(struct inode *inode, u64 flush_tid,
3426                                      struct ceph_mds_caps *m,
3427                                      struct ceph_mds_session *session)
3428 {
3429         struct ceph_inode_info *ci = ceph_inode(inode);
3430         struct ceph_mds_client *mdsc = ceph_sb_to_client(inode->i_sb)->mdsc;
3431         u64 follows = le64_to_cpu(m->snap_follows);
3432         struct ceph_cap_snap *capsnap;
3433         bool flushed = false;
3434         bool wake_ci = false;
3435         bool wake_mdsc = false;
3436 
3437         dout("handle_cap_flushsnap_ack inode %p ci %p mds%d follows %lld\n",
3438              inode, ci, session->s_mds, follows);
3439 
3440         spin_lock(&ci->i_ceph_lock);
3441         list_for_each_entry(capsnap, &ci->i_cap_snaps, ci_item) {
3442                 if (capsnap->follows == follows) {
3443                         if (capsnap->cap_flush.tid != flush_tid) {
3444                                 dout(" cap_snap %p follows %lld tid %lld !="
3445                                      " %lld\n", capsnap, follows,
3446                                      flush_tid, capsnap->cap_flush.tid);
3447                                 break;
3448                         }
3449                         flushed = true;
3450                         break;
3451                 } else {
3452                         dout(" skipping cap_snap %p follows %lld\n",
3453                              capsnap, capsnap->follows);
3454                 }
3455         }
3456         if (flushed) {
3457                 WARN_ON(capsnap->dirty_pages || capsnap->writing);
3458                 dout(" removing %p cap_snap %p follows %lld\n",
3459                      inode, capsnap, follows);
3460                 list_del(&capsnap->ci_item);
3461                 if (__finish_cap_flush(NULL, ci, &capsnap->cap_flush))
3462                         wake_ci = true;
3463 
3464                 spin_lock(&mdsc->cap_dirty_lock);
3465 
3466                 if (list_empty(&ci->i_cap_flush_list))
3467                         list_del_init(&ci->i_flushing_item);
3468 
3469                 if (__finish_cap_flush(mdsc, NULL, &capsnap->cap_flush))
3470                         wake_mdsc = true;
3471 
3472                 spin_unlock(&mdsc->cap_dirty_lock);
3473         }
3474         spin_unlock(&ci->i_ceph_lock);
3475         if (flushed) {
3476                 ceph_put_snap_context(capsnap->context);
3477                 ceph_put_cap_snap(capsnap);
3478                 if (wake_ci)
3479                         wake_up_all(&ci->i_cap_wq);
3480                 if (wake_mdsc)
3481                         wake_up_all(&mdsc->cap_flushing_wq);
3482                 iput(inode);
3483         }
3484 }
3485 
3486 /*
3487  * Handle TRUNC from MDS, indicating file truncation.
3488  *
3489  * caller hold s_mutex.
3490  */
3491 static void handle_cap_trunc(struct inode *inode,
3492                              struct ceph_mds_caps *trunc,
3493                              struct ceph_mds_session *session)
3494         __releases(ci->i_ceph_lock)
3495 {
3496         struct ceph_inode_info *ci = ceph_inode(inode);
3497         int mds = session->s_mds;
3498         int seq = le32_to_cpu(trunc->seq);
3499         u32 truncate_seq = le32_to_cpu(trunc->truncate_seq);
3500         u64 truncate_size = le64_to_cpu(trunc->truncate_size);
3501         u64 size = le64_to_cpu(trunc->size);
3502         int implemented = 0;
3503         int dirty = __ceph_caps_dirty(ci);
3504         int issued = __ceph_caps_issued(ceph_inode(inode), &implemented);
3505         int queue_trunc = 0;
3506 
3507         issued |= implemented | dirty;
3508 
3509         dout("handle_cap_trunc inode %p mds%d seq %d to %lld seq %d\n",
3510              inode, mds, seq, truncate_size, truncate_seq);
3511         queue_trunc = ceph_fill_file_size(inode, issued,
3512                                           truncate_seq, truncate_size, size);
3513         spin_unlock(&ci->i_ceph_lock);
3514 
3515         if (queue_trunc)
3516                 ceph_queue_vmtruncate(inode);
3517 }
3518 
3519 /*
3520  * Handle EXPORT from MDS.  Cap is being migrated _from_ this mds to a
3521  * different one.  If we are the most recent migration we've seen (as
3522  * indicated by mseq), make note of the migrating cap bits for the
3523  * duration (until we see the corresponding IMPORT).
3524  *
3525  * caller holds s_mutex
3526  */
3527 static void handle_cap_export(struct inode *inode, struct ceph_mds_caps *ex,
3528                               struct ceph_mds_cap_peer *ph,
3529                               struct ceph_mds_session *session)
3530 {
3531         struct ceph_mds_client *mdsc = ceph_inode_to_client(inode)->mdsc;
3532         struct ceph_mds_session *tsession = NULL;
3533         struct ceph_cap *cap, *tcap, *new_cap = NULL;
3534         struct ceph_inode_info *ci = ceph_inode(inode);
3535         u64 t_cap_id;
3536         unsigned mseq = le32_to_cpu(ex->migrate_seq);
3537         unsigned t_seq, t_mseq;
3538         int target, issued;
3539         int mds = session->s_mds;
3540 
3541         if (ph) {
3542                 t_cap_id = le64_to_cpu(ph->cap_id);
3543                 t_seq = le32_to_cpu(ph->seq);
3544                 t_mseq = le32_to_cpu(ph->mseq);
3545                 target = le32_to_cpu(ph->mds);
3546         } else {
3547                 t_cap_id = t_seq = t_mseq = 0;
3548                 target = -1;
3549         }
3550 
3551         dout("handle_cap_export inode %p ci %p mds%d mseq %d target %d\n",
3552              inode, ci, mds, mseq, target);
3553 retry:
3554         spin_lock(&ci->i_ceph_lock);
3555         cap = __get_cap_for_mds(ci, mds);
3556         if (!cap || cap->cap_id != le64_to_cpu(ex->cap_id))
3557                 goto out_unlock;
3558 
3559         if (target < 0) {
3560                 if (cap->mds_wanted | cap->issued)
3561                         ci->i_ceph_flags |= CEPH_I_CAP_DROPPED;
3562                 __ceph_remove_cap(cap, false);
3563                 goto out_unlock;
3564         }
3565 
3566         /*
3567          * now we know we haven't received the cap import message yet
3568          * because the exported cap still exist.
3569          */
3570 
3571         issued = cap->issued;
3572         if (issued != cap->implemented)
3573                 pr_err_ratelimited("handle_cap_export: issued != implemented: "
3574                                 "ino (%llx.%llx) mds%d seq %d mseq %d "
3575                                 "issued %s implemented %s\n",
3576                                 ceph_vinop(inode), mds, cap->seq, cap->mseq,
3577                                 ceph_cap_string(issued),
3578                                 ceph_cap_string(cap->implemented));
3579 
3580 
3581         tcap = __get_cap_for_mds(ci, target);
3582         if (tcap) {
3583                 /* already have caps from the target */
3584                 if (tcap->cap_id == t_cap_id &&
3585                     ceph_seq_cmp(tcap->seq, t_seq) < 0) {
3586                         dout(" updating import cap %p mds%d\n", tcap, target);
3587                         tcap->cap_id = t_cap_id;
3588                         tcap->seq = t_seq - 1;
3589                         tcap->issue_seq = t_seq - 1;
3590                         tcap->issued |= issued;
3591                         tcap->implemented |= issued;
3592                         if (cap == ci->i_auth_cap)
3593                                 ci->i_auth_cap = tcap;
3594 
3595                         if (!list_empty(&ci->i_cap_flush_list) &&
3596                             ci->i_auth_cap == tcap) {
3597                                 spin_lock(&mdsc->cap_dirty_lock);
3598                                 list_move_tail(&ci->i_flushing_item,
3599                                                &tcap->session->s_cap_flushing);
3600                                 spin_unlock(&mdsc->cap_dirty_lock);
3601                         }
3602                 }
3603                 __ceph_remove_cap(cap, false);
3604                 goto out_unlock;
3605         } else if (tsession) {
3606                 /* add placeholder for the export tagert */
3607                 int flag = (cap == ci->i_auth_cap) ? CEPH_CAP_FLAG_AUTH : 0;
3608                 tcap = new_cap;
3609                 ceph_add_cap(inode, tsession, t_cap_id, -1, issued, 0,
3610                              t_seq - 1, t_mseq, (u64)-1, flag, &new_cap);
3611 
3612                 if (!list_empty(&ci->i_cap_flush_list) &&
3613                     ci->i_auth_cap == tcap) {
3614                         spin_lock(&mdsc->cap_dirty_lock);
3615                         list_move_tail(&ci->i_flushing_item,
3616                                        &tcap->session->s_cap_flushing);
3617                         spin_unlock(&mdsc->cap_dirty_lock);
3618                 }
3619 
3620                 __ceph_remove_cap(cap, false);
3621                 goto out_unlock;
3622         }
3623 
3624         spin_unlock(&ci->i_ceph_lock);
3625         mutex_unlock(&session->s_mutex);
3626 
3627         /* open target session */
3628         tsession = ceph_mdsc_open_export_target_session(mdsc, target);
3629         if (!IS_ERR(tsession)) {
3630                 if (mds > target) {
3631                         mutex_lock(&session->s_mutex);
3632                         mutex_lock_nested(&tsession->s_mutex,
3633                                           SINGLE_DEPTH_NESTING);
3634                 } else {
3635                         mutex_lock(&tsession->s_mutex);
3636                         mutex_lock_nested(&session->s_mutex,
3637                                           SINGLE_DEPTH_NESTING);
3638                 }
3639                 new_cap = ceph_get_cap(mdsc, NULL);
3640         } else {
3641                 WARN_ON(1);
3642                 tsession = NULL;
3643                 target = -1;
3644         }
3645         goto retry;
3646 
3647 out_unlock:
3648         spin_unlock(&ci->i_ceph_lock);
3649         mutex_unlock(&session->s_mutex);
3650         if (tsession) {
3651                 mutex_unlock(&tsession->s_mutex);
3652                 ceph_put_mds_session(tsession);
3653         }
3654         if (new_cap)
3655                 ceph_put_cap(mdsc, new_cap);
3656 }
3657 
3658 /*
3659  * Handle cap IMPORT.
3660  *
3661  * caller holds s_mutex. acquires i_ceph_lock
3662  */
3663 static void handle_cap_import(struct ceph_mds_client *mdsc,
3664                               struct inode *inode, struct ceph_mds_caps *im,
3665                               struct ceph_mds_cap_peer *ph,
3666                               struct ceph_mds_session *session,
3667                               struct ceph_cap **target_cap, int *old_issued)
3668         __acquires(ci->i_ceph_lock)
3669 {
3670         struct ceph_inode_info *ci = ceph_inode(inode);
3671         struct ceph_cap *cap, *ocap, *new_cap = NULL;
3672         int mds = session->s_mds;
3673         int issued;
3674         unsigned caps = le32_to_cpu(im->caps);
3675         unsigned wanted = le32_to_cpu(im->wanted);
3676         unsigned seq = le32_to_cpu(im->seq);
3677         unsigned mseq = le32_to_cpu(im->migrate_seq);
3678         u64 realmino = le64_to_cpu(im->realm);
3679         u64 cap_id = le64_to_cpu(im->cap_id);
3680         u64 p_cap_id;
3681         int peer;
3682 
3683         if (ph) {
3684                 p_cap_id = le64_to_cpu(ph->cap_id);
3685                 peer = le32_to_cpu(ph->mds);
3686         } else {
3687                 p_cap_id = 0;
3688                 peer = -1;
3689         }
3690 
3691         dout("handle_cap_import inode %p ci %p mds%d mseq %d peer %d\n",
3692              inode, ci, mds, mseq, peer);
3693 
3694 retry:
3695         spin_lock(&ci->i_ceph_lock);
3696         cap = __get_cap_for_mds(ci, mds);
3697         if (!cap) {
3698                 if (!new_cap) {
3699                         spin_unlock(&ci->i_ceph_lock);
3700                         new_cap = ceph_get_cap(mdsc, NULL);
3701                         goto retry;
3702                 }
3703                 cap = new_cap;
3704         } else {
3705                 if (new_cap) {
3706                         ceph_put_cap(mdsc, new_cap);
3707                         new_cap = NULL;
3708                 }
3709         }
3710 
3711         __ceph_caps_issued(ci, &issued);
3712         issued |= __ceph_caps_dirty(ci);
3713 
3714         ceph_add_cap(inode, session, cap_id, -1, caps, wanted, seq, mseq,
3715                      realmino, CEPH_CAP_FLAG_AUTH, &new_cap);
3716 
3717         ocap = peer >= 0 ? __get_cap_for_mds(ci, peer) : NULL;
3718         if (ocap && ocap->cap_id == p_cap_id) {
3719                 dout(" remove export cap %p mds%d flags %d\n",
3720                      ocap, peer, ph->flags);
3721                 if ((ph->flags & CEPH_CAP_FLAG_AUTH) &&
3722                     (ocap->seq != le32_to_cpu(ph->seq) ||
3723                      ocap->mseq != le32_to_cpu(ph->mseq))) {
3724                         pr_err_ratelimited("handle_cap_import: "
3725                                         "mismatched seq/mseq: ino (%llx.%llx) "
3726                                         "mds%d seq %d mseq %d importer mds%d "
3727                                         "has peer seq %d mseq %d\n",
3728                                         ceph_vinop(inode), peer, ocap->seq,
3729                                         ocap->mseq, mds, le32_to_cpu(ph->seq),
3730                                         le32_to_cpu(ph->mseq));
3731                 }
3732                 __ceph_remove_cap(ocap, (ph->flags & CEPH_CAP_FLAG_RELEASE));
3733         }
3734 
3735         /* make sure we re-request max_size, if necessary */
3736         ci->i_requested_max_size = 0;
3737 
3738         *old_issued = issued;
3739         *target_cap = cap;
3740 }
3741 
3742 /*
3743  * Handle a caps message from the MDS.
3744  *
3745  * Identify the appropriate session, inode, and call the right handler
3746  * based on the cap op.
3747  */
3748 void ceph_handle_caps(struct ceph_mds_session *session,
3749                       struct ceph_msg *msg)
3750 {
3751         struct ceph_mds_client *mdsc = session->s_mdsc;
3752         struct inode *inode;
3753         struct ceph_inode_info *ci;
3754         struct ceph_cap *cap;
3755         struct ceph_mds_caps *h;
3756         struct ceph_mds_cap_peer *peer = NULL;
3757         struct ceph_snap_realm *realm = NULL;
3758         int op;
3759         int msg_version = le16_to_cpu(msg->hdr.version);
3760         u32 seq, mseq;
3761         struct ceph_vino vino;
3762         void *snaptrace;
3763         size_t snaptrace_len;
3764         void *p, *end;
3765         struct cap_extra_info extra_info = {};
3766 
3767         dout("handle_caps from mds%d\n", session->s_mds);
3768 
3769         /* decode */
3770         end = msg->front.iov_base + msg->front.iov_len;
3771         if (msg->front.iov_len < sizeof(*h))
3772                 goto bad;
3773         h = msg->front.iov_base;
3774         op = le32_to_cpu(h->op);
3775         vino.ino = le64_to_cpu(h->ino);
3776         vino.snap = CEPH_NOSNAP;
3777         seq = le32_to_cpu(h->seq);
3778         mseq = le32_to_cpu(h->migrate_seq);
3779 
3780         snaptrace = h + 1;
3781         snaptrace_len = le32_to_cpu(h->snap_trace_len);
3782         p = snaptrace + snaptrace_len;
3783 
3784         if (msg_version >= 2) {
3785                 u32 flock_len;
3786                 ceph_decode_32_safe(&p, end, flock_len, bad);
3787                 if (p + flock_len > end)
3788                         goto bad;
3789                 p += flock_len;
3790         }
3791 
3792         if (msg_version >= 3) {
3793                 if (op == CEPH_CAP_OP_IMPORT) {
3794                         if (p + sizeof(*peer) > end)
3795                                 goto bad;
3796                         peer = p;
3797                         p += sizeof(*peer);
3798                 } else if (op == CEPH_CAP_OP_EXPORT) {
3799                         /* recorded in unused fields */
3800                         peer = (void *)&h->size;
3801                 }
3802         }
3803 
3804         if (msg_version >= 4) {
3805                 ceph_decode_64_safe(&p, end, extra_info.inline_version, bad);
3806                 ceph_decode_32_safe(&p, end, extra_info.inline_len, bad);
3807                 if (p + extra_info.inline_len > end)
3808                         goto bad;
3809                 extra_info.inline_data = p;
3810                 p += extra_info.inline_len;
3811         }
3812 
3813         if (msg_version >= 5) {
3814                 struct ceph_osd_client  *osdc = &mdsc->fsc->client->osdc;
3815                 u32                     epoch_barrier;
3816 
3817                 ceph_decode_32_safe(&p, end, epoch_barrier, bad);
3818                 ceph_osdc_update_epoch_barrier(osdc, epoch_barrier);
3819         }
3820 
3821         if (msg_version >= 8) {
3822                 u64 flush_tid;
3823                 u32 caller_uid, caller_gid;
3824                 u32 pool_ns_len;
3825 
3826                 /* version >= 6 */
3827                 ceph_decode_64_safe(&p, end, flush_tid, bad);
3828                 /* version >= 7 */
3829                 ceph_decode_32_safe(&p, end, caller_uid, bad);
3830                 ceph_decode_32_safe(&p, end, caller_gid, bad);
3831                 /* version >= 8 */
3832                 ceph_decode_32_safe(&p, end, pool_ns_len, bad);
3833                 if (pool_ns_len > 0) {
3834                         ceph_decode_need(&p, end, pool_ns_len, bad);
3835                         extra_info.pool_ns =
3836                                 ceph_find_or_create_string(p, pool_ns_len);
3837                         p += pool_ns_len;
3838                 }
3839         }
3840 
3841         if (msg_version >= 11) {
3842                 struct ceph_timespec *btime;
3843                 u64 change_attr;
3844                 u32 flags;
3845 
3846                 /* version >= 9 */
3847                 if (p + sizeof(*btime) > end)
3848                         goto bad;
3849                 btime = p;
3850                 p += sizeof(*btime);
3851                 ceph_decode_64_safe(&p, end, change_attr, bad);
3852                 /* version >= 10 */
3853                 ceph_decode_32_safe(&p, end, flags, bad);
3854                 /* version >= 11 */
3855                 extra_info.dirstat_valid = true;
3856                 ceph_decode_64_safe(&p, end, extra_info.nfiles, bad);
3857                 ceph_decode_64_safe(&p, end, extra_info.nsubdirs, bad);
3858         }
3859 
3860         /* lookup ino */
3861         inode = ceph_find_inode(mdsc->fsc->sb, vino);
3862         ci = ceph_inode(inode);
3863         dout(" op %s ino %llx.%llx inode %p\n", ceph_cap_op_name(op), vino.ino,
3864              vino.snap, inode);
3865 
3866         mutex_lock(&session->s_mutex);
3867         session->s_seq++;
3868         dout(" mds%d seq %lld cap seq %u\n", session->s_mds, session->s_seq,
3869              (unsigned)seq);
3870 
3871         if (!inode) {
3872                 dout(" i don't have ino %llx\n", vino.ino);
3873 
3874                 if (op == CEPH_CAP_OP_IMPORT) {
3875                         cap = ceph_get_cap(mdsc, NULL);
3876                         cap->cap_ino = vino.ino;
3877                         cap->queue_release = 1;
3878                         cap->cap_id = le64_to_cpu(h->cap_id);
3879                         cap->mseq = mseq;
3880                         cap->seq = seq;
3881                         cap->issue_seq = seq;
3882                         spin_lock(&session->s_cap_lock);
3883                         list_add_tail(&cap->session_caps,
3884                                         &session->s_cap_releases);
3885                         session->s_num_cap_releases++;
3886                         spin_unlock(&session->s_cap_lock);
3887                 }
3888                 goto flush_cap_releases;
3889         }
3890 
3891         /* these will work even if we don't have a cap yet */
3892         switch (op) {
3893         case CEPH_CAP_OP_FLUSHSNAP_ACK:
3894                 handle_cap_flushsnap_ack(inode, le64_to_cpu(msg->hdr.tid),
3895                                          h, session);
3896                 goto done;
3897 
3898         case CEPH_CAP_OP_EXPORT:
3899                 handle_cap_export(inode, h, peer, session);
3900                 goto done_unlocked;
3901 
3902         case CEPH_CAP_OP_IMPORT:
3903                 realm = NULL;
3904                 if (snaptrace_len) {
3905                         down_write(&mdsc->snap_rwsem);
3906                         ceph_update_snap_trace(mdsc, snaptrace,
3907                                                snaptrace + snaptrace_len,
3908                                                false, &realm);
3909                         downgrade_write(&mdsc->snap_rwsem);
3910                 } else {
3911                         down_read(&mdsc->snap_rwsem);
3912                 }
3913                 handle_cap_import(mdsc, inode, h, peer, session,
3914                                   &cap, &extra_info.issued);
3915                 handle_cap_grant(inode, session, cap,
3916                                  h, msg->middle, &extra_info);
3917                 if (realm)
3918                         ceph_put_snap_realm(mdsc, realm);
3919                 goto done_unlocked;
3920         }
3921 
3922         /* the rest require a cap */
3923         spin_lock(&ci->i_ceph_lock);
3924         cap = __get_cap_for_mds(ceph_inode(inode), session->s_mds);
3925         if (!cap) {
3926                 dout(" no cap on %p ino %llx.%llx from mds%d\n",
3927                      inode, ceph_ino(inode), ceph_snap(inode),
3928                      session->s_mds);
3929                 spin_unlock(&ci->i_ceph_lock);
3930                 goto flush_cap_releases;
3931         }
3932 
3933         /* note that each of these drops i_ceph_lock for us */
3934         switch (op) {
3935         case CEPH_CAP_OP_REVOKE:
3936         case CEPH_CAP_OP_GRANT:
3937                 __ceph_caps_issued(ci, &extra_info.issued);
3938                 extra_info.issued |= __ceph_caps_dirty(ci);
3939                 handle_cap_grant(inode, session, cap,
3940                                  h, msg->middle, &extra_info);
3941                 goto done_unlocked;
3942 
3943         case CEPH_CAP_OP_FLUSH_ACK:
3944                 handle_cap_flush_ack(inode, le64_to_cpu(msg->hdr.tid),
3945                                      h, session, cap);
3946                 break;
3947 
3948         case CEPH_CAP_OP_TRUNC:
3949                 handle_cap_trunc(inode, h, session);
3950                 break;
3951 
3952         default:
3953                 spin_unlock(&ci->i_ceph_lock);
3954                 pr_err("ceph_handle_caps: unknown cap op %d %s\n", op,
3955                        ceph_cap_op_name(op));
3956         }
3957 
3958         goto done;
3959 
3960 flush_cap_releases:
3961         /*
3962          * send any cap release message to try to move things
3963          * along for the mds (who clearly thinks we still have this
3964          * cap).
3965          */
3966         ceph_send_cap_releases(mdsc, session);
3967 
3968 done:
3969         mutex_unlock(&session->s_mutex);
3970 done_unlocked:
3971         iput(inode);
3972         ceph_put_string(extra_info.pool_ns);
3973         return;
3974 
3975 bad:
3976         pr_err("ceph_handle_caps: corrupt message\n");
3977         ceph_msg_dump(msg);
3978         return;
3979 }
3980 
3981 /*
3982  * Delayed work handler to process end of delayed cap release LRU list.
3983  */
3984 void ceph_check_delayed_caps(struct ceph_mds_client *mdsc)
3985 {
3986         struct inode *inode;
3987         struct ceph_inode_info *ci;
3988         int flags = CHECK_CAPS_NODELAY;
3989 
3990         dout("check_delayed_caps\n");
3991         while (1) {
3992                 spin_lock(&mdsc->cap_delay_lock);
3993                 if (list_empty(&mdsc->cap_delay_list))
3994                         break;
3995                 ci = list_first_entry(&mdsc->cap_delay_list,
3996                                       struct ceph_inode_info,
3997                                       i_cap_delay_list);
3998                 if ((ci->i_ceph_flags & CEPH_I_FLUSH) == 0 &&
3999                     time_before(jiffies, ci->i_hold_caps_max))
4000                         break;
4001                 list_del_init(&ci->i_cap_delay_list);
4002 
4003                 inode = igrab(&ci->vfs_inode);
4004                 spin_unlock(&mdsc->cap_delay_lock);
4005 
4006                 if (inode) {
4007                         dout("check_delayed_caps on %p\n", inode);
4008                         ceph_check_caps(ci, flags, NULL);
4009                         iput(inode);
4010                 }
4011         }
4012         spin_unlock(&mdsc->cap_delay_lock);
4013 }
4014 
4015 /*
4016  * Flush all dirty caps to the mds
4017  */
4018 void ceph_flush_dirty_caps(struct ceph_mds_client *mdsc)
4019 {
4020         struct ceph_inode_info *ci;
4021         struct inode *inode;
4022 
4023         dout("flush_dirty_caps\n");
4024         spin_lock(&mdsc->cap_dirty_lock);
4025         while (!list_empty(&mdsc->cap_dirty)) {
4026                 ci = list_first_entry(&mdsc->cap_dirty, struct ceph_inode_info,
4027                                       i_dirty_item);
4028                 inode = &ci->vfs_inode;
4029                 ihold(inode);
4030                 dout("flush_dirty_caps %p\n", inode);
4031                 spin_unlock(&mdsc->cap_dirty_lock);
4032                 ceph_check_caps(ci, CHECK_CAPS_NODELAY|CHECK_CAPS_FLUSH, NULL);
4033                 iput(inode);
4034                 spin_lock(&mdsc->cap_dirty_lock);
4035         }
4036         spin_unlock(&mdsc->cap_dirty_lock);
4037         dout("flush_dirty_caps done\n");
4038 }
4039 
4040 void __ceph_get_fmode(struct ceph_inode_info *ci, int fmode)
4041 {
4042         int i;
4043         int bits = (fmode << 1) | 1;
4044         for (i = 0; i < CEPH_FILE_MODE_BITS; i++) {
4045                 if (bits & (1 << i))
4046                         ci->i_nr_by_mode[i]++;
4047         }
4048 }
4049 
4050 /*
4051  * Drop open file reference.  If we were the last open file,
4052  * we may need to release capabilities to the MDS (or schedule
4053  * their delayed release).
4054  */
4055 void ceph_put_fmode(struct ceph_inode_info *ci, int fmode)
4056 {
4057         int i, last = 0;
4058         int bits = (fmode << 1) | 1;
4059         spin_lock(&ci->i_ceph_lock);
4060         for (i = 0; i < CEPH_FILE_MODE_BITS; i++) {
4061                 if (bits & (1 << i)) {
4062                         BUG_ON(ci->i_nr_by_mode[i] == 0);
4063                         if (--ci->i_nr_by_mode[i] == 0)
4064                                 last++;
4065                 }
4066         }
4067         dout("put_fmode %p fmode %d {%d,%d,%d,%d}\n",
4068              &ci->vfs_inode, fmode,
4069              ci->i_nr_by_mode[0], ci->i_nr_by_mode[1],
4070              ci->i_nr_by_mode[2], ci->i_nr_by_mode[3]);
4071         spin_unlock(&ci->i_ceph_lock);
4072 
4073         if (last && ci->i_vino.snap == CEPH_NOSNAP)
4074                 ceph_check_caps(ci, 0, NULL);
4075 }
4076 
4077 /*
4078  * For a soon-to-be unlinked file, drop the AUTH_RDCACHE caps. If it
4079  * looks like the link count will hit 0, drop any other caps (other
4080  * than PIN) we don't specifically want (due to the file still being
4081  * open).
4082  */
4083 int ceph_drop_caps_for_unlink(struct inode *inode)
4084 {
4085         struct ceph_inode_info *ci = ceph_inode(inode);
4086         int drop = CEPH_CAP_LINK_SHARED | CEPH_CAP_LINK_EXCL;
4087 
4088         spin_lock(&ci->i_ceph_lock);
4089         if (inode->i_nlink == 1) {
4090                 drop |= ~(__ceph_caps_wanted(ci) | CEPH_CAP_PIN);
4091 
4092                 ci->i_ceph_flags |= CEPH_I_NODELAY;
4093                 if (__ceph_caps_dirty(ci)) {
4094                         struct ceph_mds_client *mdsc =
4095                                 ceph_inode_to_client(inode)->mdsc;
4096                         __cap_delay_requeue_front(mdsc, ci);
4097                 }
4098         }
4099         spin_unlock(&ci->i_ceph_lock);
4100         return drop;
4101 }
4102 
4103 /*
4104  * Helpers for embedding cap and dentry lease releases into mds
4105  * requests.
4106  *
4107  * @force is used by dentry_release (below) to force inclusion of a
4108  * record for the directory inode, even when there aren't any caps to
4109  * drop.
4110  */
4111 int ceph_encode_inode_release(void **p, struct inode *inode,
4112                               int mds, int drop, int unless, int force)
4113 {
4114         struct ceph_inode_info *ci = ceph_inode(inode);
4115         struct ceph_cap *cap;
4116         struct ceph_mds_request_release *rel = *p;
4117         int used, dirty;
4118         int ret = 0;
4119 
4120         spin_lock(&ci->i_ceph_lock);
4121         used = __ceph_caps_used(ci);
4122         dirty = __ceph_caps_dirty(ci);
4123 
4124         dout("encode_inode_release %p mds%d used|dirty %s drop %s unless %s\n",
4125              inode, mds, ceph_cap_string(used|dirty), ceph_cap_string(drop),
4126              ceph_cap_string(unless));
4127 
4128         /* only drop unused, clean caps */
4129         drop &= ~(used | dirty);
4130 
4131         cap = __get_cap_for_mds(ci, mds);
4132         if (cap && __cap_is_valid(cap)) {
4133                 unless &= cap->issued;
4134                 if (unless) {
4135                         if (unless & CEPH_CAP_AUTH_EXCL)
4136                                 drop &= ~CEPH_CAP_AUTH_SHARED;
4137                         if (unless & CEPH_CAP_LINK_EXCL)
4138                                 drop &= ~CEPH_CAP_LINK_SHARED;
4139                         if (unless & CEPH_CAP_XATTR_EXCL)
4140                                 drop &= ~CEPH_CAP_XATTR_SHARED;
4141                         if (unless & CEPH_CAP_FILE_EXCL)
4142                                 drop &= ~CEPH_CAP_FILE_SHARED;
4143                 }
4144 
4145                 if (force || (cap->issued & drop)) {
4146                         if (cap->issued & drop) {
4147                                 int wanted = __ceph_caps_wanted(ci);
4148                                 if ((ci->i_ceph_flags & CEPH_I_NODELAY) == 0)
4149                                         wanted |= cap->mds_wanted;
4150                                 dout("encode_inode_release %p cap %p "
4151                                      "%s -> %s, wanted %s -> %s\n", inode, cap,
4152                                      ceph_cap_string(cap->issued),
4153                                      ceph_cap_string(cap->issued & ~drop),
4154                                      ceph_cap_string(cap->mds_wanted),
4155                                      ceph_cap_string(wanted));
4156 
4157                                 cap->issued &= ~drop;
4158                                 cap->implemented &= ~drop;
4159                                 cap->mds_wanted = wanted;
4160                         } else {
4161                                 dout("encode_inode_release %p cap %p %s"
4162                                      " (force)\n", inode, cap,
4163                                      ceph_cap_string(cap->issued));
4164                         }
4165 
4166                         rel->ino = cpu_to_le64(ceph_ino(inode));
4167                         rel->cap_id = cpu_to_le64(cap->cap_id);
4168                         rel->seq = cpu_to_le32(cap->seq);
4169                         rel->issue_seq = cpu_to_le32(cap->issue_seq);
4170                         rel->mseq = cpu_to_le32(cap->mseq);
4171                         rel->caps = cpu_to_le32(cap->implemented);
4172                         rel->wanted = cpu_to_le32(cap->mds_wanted);
4173                         rel->dname_len = 0;
4174                         rel->dname_seq = 0;
4175                         *p += sizeof(*rel);
4176                         ret = 1;
4177                 } else {
4178                         dout("encode_inode_release %p cap %p %s (noop)\n",
4179                              inode, cap, ceph_cap_string(cap->issued));
4180                 }
4181         }
4182         spin_unlock(&ci->i_ceph_lock);
4183         return ret;
4184 }
4185 
4186 int ceph_encode_dentry_release(void **p, struct dentry *dentry,
4187                                struct inode *dir,
4188                                int mds, int drop, int unless)
4189 {
4190         struct dentry *parent = NULL;
4191         struct ceph_mds_request_release *rel = *p;
4192         struct ceph_dentry_info *di = ceph_dentry(dentry);
4193         int force = 0;
4194         int ret;
4195 
4196         /*
4197          * force an record for the directory caps if we have a dentry lease.
4198          * this is racy (can't take i_ceph_lock and d_lock together), but it
4199          * doesn't have to be perfect; the mds will revoke anything we don't
4200          * release.
4201          */
4202         spin_lock(&dentry->d_lock);
4203         if (di->lease_session && di->lease_session->s_mds == mds)
4204                 force = 1;
4205         if (!dir) {
4206                 parent = dget(dentry->d_parent);
4207                 dir = d_inode(parent);
4208         }
4209         spin_unlock(&dentry->d_lock);
4210 
4211         ret = ceph_encode_inode_release(p, dir, mds, drop, unless, force);
4212         dput(parent);
4213 
4214         spin_lock(&dentry->d_lock);
4215         if (ret && di->lease_session && di->lease_session->s_mds == mds) {
4216                 dout("encode_dentry_release %p mds%d seq %d\n",
4217                      dentry, mds, (int)di->lease_seq);
4218                 rel->dname_len = cpu_to_le32(dentry->d_name.len);
4219                 memcpy(*p, dentry->d_name.name, dentry->d_name.len);
4220                 *p += dentry->d_name.len;
4221                 rel->dname_seq = cpu_to_le32(di->lease_seq);
4222                 __ceph_mdsc_drop_dentry_lease(dentry);
4223         }
4224         spin_unlock(&dentry->d_lock);
4225         return ret;
4226 }
4227 

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