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

Version: ~ [ linux-5.6 ] ~ [ linux-5.5.13 ] ~ [ linux-5.4.28 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.113 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.174 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.217 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.217 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.140 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.82 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-3.9.11 ] ~ [ linux-3.8.13 ] ~ [ linux-3.7.10 ] ~ [ linux-3.6.11 ] ~ [ linux-3.5.7 ] ~ [ linux-3.4.113 ] ~ [ linux-3.3.8 ] ~ [ linux-3.2.102 ] ~ [ linux-3.1.10 ] ~ [ linux-3.0.101 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  1 #include <linux/ceph/ceph_debug.h>
  2 
  3 #include <linux/fs.h>
  4 #include <linux/kernel.h>
  5 #include <linux/sched.h>
  6 #include <linux/slab.h>
  7 #include <linux/vmalloc.h>
  8 #include <linux/wait.h>
  9 #include <linux/writeback.h>
 10 
 11 #include "super.h"
 12 #include "mds_client.h"
 13 #include <linux/ceph/decode.h>
 14 #include <linux/ceph/messenger.h>
 15 
 16 /*
 17  * Capability management
 18  *
 19  * The Ceph metadata servers control client access to inode metadata
 20  * and file data by issuing capabilities, granting clients permission
 21  * to read and/or write both inode field and file data to OSDs
 22  * (storage nodes).  Each capability consists of a set of bits
 23  * indicating which operations are allowed.
 24  *
 25  * If the client holds a *_SHARED cap, the client has a coherent value
 26  * that can be safely read from the cached inode.
 27  *
 28  * In the case of a *_EXCL (exclusive) or FILE_WR capabilities, the
 29  * client is allowed to change inode attributes (e.g., file size,
 30  * mtime), note its dirty state in the ceph_cap, and asynchronously
 31  * flush that metadata change to the MDS.
 32  *
 33  * In the event of a conflicting operation (perhaps by another
 34  * client), the MDS will revoke the conflicting client capabilities.
 35  *
 36  * In order for a client to cache an inode, it must hold a capability
 37  * with at least one MDS server.  When inodes are released, release
 38  * notifications are batched and periodically sent en masse to the MDS
 39  * cluster to release server state.
 40  */
 41 
 42 
 43 /*
 44  * Generate readable cap strings for debugging output.
 45  */
 46 #define MAX_CAP_STR 20
 47 static char cap_str[MAX_CAP_STR][40];
 48 static DEFINE_SPINLOCK(cap_str_lock);
 49 static int last_cap_str;
 50 
 51 static char *gcap_string(char *s, int c)
 52 {
 53         if (c & CEPH_CAP_GSHARED)
 54                 *s++ = 's';
 55         if (c & CEPH_CAP_GEXCL)
 56                 *s++ = 'x';
 57         if (c & CEPH_CAP_GCACHE)
 58                 *s++ = 'c';
 59         if (c & CEPH_CAP_GRD)
 60                 *s++ = 'r';
 61         if (c & CEPH_CAP_GWR)
 62                 *s++ = 'w';
 63         if (c & CEPH_CAP_GBUFFER)
 64                 *s++ = 'b';
 65         if (c & CEPH_CAP_GLAZYIO)
 66                 *s++ = 'l';
 67         return s;
 68 }
 69 
 70 const char *ceph_cap_string(int caps)
 71 {
 72         int i;
 73         char *s;
 74         int c;
 75 
 76         spin_lock(&cap_str_lock);
 77         i = last_cap_str++;
 78         if (last_cap_str == MAX_CAP_STR)
 79                 last_cap_str = 0;
 80         spin_unlock(&cap_str_lock);
 81 
 82         s = cap_str[i];
 83 
 84         if (caps & CEPH_CAP_PIN)
 85                 *s++ = 'p';
 86 
 87         c = (caps >> CEPH_CAP_SAUTH) & 3;
 88         if (c) {
 89                 *s++ = 'A';
 90                 s = gcap_string(s, c);
 91         }
 92 
 93         c = (caps >> CEPH_CAP_SLINK) & 3;
 94         if (c) {
 95                 *s++ = 'L';
 96                 s = gcap_string(s, c);
 97         }
 98 
 99         c = (caps >> CEPH_CAP_SXATTR) & 3;
100         if (c) {
101                 *s++ = 'X';
102                 s = gcap_string(s, c);
103         }
104 
105         c = caps >> CEPH_CAP_SFILE;
106         if (c) {
107                 *s++ = 'F';
108                 s = gcap_string(s, c);
109         }
110 
111         if (s == cap_str[i])
112                 *s++ = '-';
113         *s = 0;
114         return cap_str[i];
115 }
116 
117 void ceph_caps_init(struct ceph_mds_client *mdsc)
118 {
119         INIT_LIST_HEAD(&mdsc->caps_list);
120         spin_lock_init(&mdsc->caps_list_lock);
121 }
122 
123 void ceph_caps_finalize(struct ceph_mds_client *mdsc)
124 {
125         struct ceph_cap *cap;
126 
127         spin_lock(&mdsc->caps_list_lock);
128         while (!list_empty(&mdsc->caps_list)) {
129                 cap = list_first_entry(&mdsc->caps_list,
130                                        struct ceph_cap, caps_item);
131                 list_del(&cap->caps_item);
132                 kmem_cache_free(ceph_cap_cachep, cap);
133         }
134         mdsc->caps_total_count = 0;
135         mdsc->caps_avail_count = 0;
136         mdsc->caps_use_count = 0;
137         mdsc->caps_reserve_count = 0;
138         mdsc->caps_min_count = 0;
139         spin_unlock(&mdsc->caps_list_lock);
140 }
141 
142 void ceph_adjust_min_caps(struct ceph_mds_client *mdsc, int delta)
143 {
144         spin_lock(&mdsc->caps_list_lock);
145         mdsc->caps_min_count += delta;
146         BUG_ON(mdsc->caps_min_count < 0);
147         spin_unlock(&mdsc->caps_list_lock);
148 }
149 
150 int ceph_reserve_caps(struct ceph_mds_client *mdsc,
151                       struct ceph_cap_reservation *ctx, int need)
152 {
153         int i;
154         struct ceph_cap *cap;
155         int have;
156         int alloc = 0;
157         LIST_HEAD(newcaps);
158         int ret = 0;
159 
160         dout("reserve caps ctx=%p need=%d\n", ctx, need);
161 
162         /* first reserve any caps that are already allocated */
163         spin_lock(&mdsc->caps_list_lock);
164         if (mdsc->caps_avail_count >= need)
165                 have = need;
166         else
167                 have = mdsc->caps_avail_count;
168         mdsc->caps_avail_count -= have;
169         mdsc->caps_reserve_count += have;
170         BUG_ON(mdsc->caps_total_count != mdsc->caps_use_count +
171                                          mdsc->caps_reserve_count +
172                                          mdsc->caps_avail_count);
173         spin_unlock(&mdsc->caps_list_lock);
174 
175         for (i = have; i < need; i++) {
176                 cap = kmem_cache_alloc(ceph_cap_cachep, GFP_NOFS);
177                 if (!cap) {
178                         ret = -ENOMEM;
179                         goto out_alloc_count;
180                 }
181                 list_add(&cap->caps_item, &newcaps);
182                 alloc++;
183         }
184         BUG_ON(have + alloc != need);
185 
186         spin_lock(&mdsc->caps_list_lock);
187         mdsc->caps_total_count += alloc;
188         mdsc->caps_reserve_count += alloc;
189         list_splice(&newcaps, &mdsc->caps_list);
190 
191         BUG_ON(mdsc->caps_total_count != mdsc->caps_use_count +
192                                          mdsc->caps_reserve_count +
193                                          mdsc->caps_avail_count);
194         spin_unlock(&mdsc->caps_list_lock);
195 
196         ctx->count = need;
197         dout("reserve caps ctx=%p %d = %d used + %d resv + %d avail\n",
198              ctx, mdsc->caps_total_count, mdsc->caps_use_count,
199              mdsc->caps_reserve_count, mdsc->caps_avail_count);
200         return 0;
201 
202 out_alloc_count:
203         /* we didn't manage to reserve as much as we needed */
204         pr_warning("reserve caps ctx=%p ENOMEM need=%d got=%d\n",
205                    ctx, need, have);
206         return ret;
207 }
208 
209 int ceph_unreserve_caps(struct ceph_mds_client *mdsc,
210                         struct ceph_cap_reservation *ctx)
211 {
212         dout("unreserve caps ctx=%p count=%d\n", ctx, ctx->count);
213         if (ctx->count) {
214                 spin_lock(&mdsc->caps_list_lock);
215                 BUG_ON(mdsc->caps_reserve_count < ctx->count);
216                 mdsc->caps_reserve_count -= ctx->count;
217                 mdsc->caps_avail_count += ctx->count;
218                 ctx->count = 0;
219                 dout("unreserve caps %d = %d used + %d resv + %d avail\n",
220                      mdsc->caps_total_count, mdsc->caps_use_count,
221                      mdsc->caps_reserve_count, mdsc->caps_avail_count);
222                 BUG_ON(mdsc->caps_total_count != mdsc->caps_use_count +
223                                                  mdsc->caps_reserve_count +
224                                                  mdsc->caps_avail_count);
225                 spin_unlock(&mdsc->caps_list_lock);
226         }
227         return 0;
228 }
229 
230 static struct ceph_cap *get_cap(struct ceph_mds_client *mdsc,
231                                 struct ceph_cap_reservation *ctx)
232 {
233         struct ceph_cap *cap = NULL;
234 
235         /* temporary, until we do something about cap import/export */
236         if (!ctx) {
237                 cap = kmem_cache_alloc(ceph_cap_cachep, GFP_NOFS);
238                 if (cap) {
239                         mdsc->caps_use_count++;
240                         mdsc->caps_total_count++;
241                 }
242                 return cap;
243         }
244 
245         spin_lock(&mdsc->caps_list_lock);
246         dout("get_cap ctx=%p (%d) %d = %d used + %d resv + %d avail\n",
247              ctx, ctx->count, mdsc->caps_total_count, mdsc->caps_use_count,
248              mdsc->caps_reserve_count, mdsc->caps_avail_count);
249         BUG_ON(!ctx->count);
250         BUG_ON(ctx->count > mdsc->caps_reserve_count);
251         BUG_ON(list_empty(&mdsc->caps_list));
252 
253         ctx->count--;
254         mdsc->caps_reserve_count--;
255         mdsc->caps_use_count++;
256 
257         cap = list_first_entry(&mdsc->caps_list, struct ceph_cap, caps_item);
258         list_del(&cap->caps_item);
259 
260         BUG_ON(mdsc->caps_total_count != mdsc->caps_use_count +
261                mdsc->caps_reserve_count + mdsc->caps_avail_count);
262         spin_unlock(&mdsc->caps_list_lock);
263         return cap;
264 }
265 
266 void ceph_put_cap(struct ceph_mds_client *mdsc, struct ceph_cap *cap)
267 {
268         spin_lock(&mdsc->caps_list_lock);
269         dout("put_cap %p %d = %d used + %d resv + %d avail\n",
270              cap, mdsc->caps_total_count, mdsc->caps_use_count,
271              mdsc->caps_reserve_count, mdsc->caps_avail_count);
272         mdsc->caps_use_count--;
273         /*
274          * Keep some preallocated caps around (ceph_min_count), to
275          * avoid lots of free/alloc churn.
276          */
277         if (mdsc->caps_avail_count >= mdsc->caps_reserve_count +
278                                       mdsc->caps_min_count) {
279                 mdsc->caps_total_count--;
280                 kmem_cache_free(ceph_cap_cachep, cap);
281         } else {
282                 mdsc->caps_avail_count++;
283                 list_add(&cap->caps_item, &mdsc->caps_list);
284         }
285 
286         BUG_ON(mdsc->caps_total_count != mdsc->caps_use_count +
287                mdsc->caps_reserve_count + mdsc->caps_avail_count);
288         spin_unlock(&mdsc->caps_list_lock);
289 }
290 
291 void ceph_reservation_status(struct ceph_fs_client *fsc,
292                              int *total, int *avail, int *used, int *reserved,
293                              int *min)
294 {
295         struct ceph_mds_client *mdsc = fsc->mdsc;
296 
297         if (total)
298                 *total = mdsc->caps_total_count;
299         if (avail)
300                 *avail = mdsc->caps_avail_count;
301         if (used)
302                 *used = mdsc->caps_use_count;
303         if (reserved)
304                 *reserved = mdsc->caps_reserve_count;
305         if (min)
306                 *min = mdsc->caps_min_count;
307 }
308 
309 /*
310  * Find ceph_cap for given mds, if any.
311  *
312  * Called with i_ceph_lock held.
313  */
314 static struct ceph_cap *__get_cap_for_mds(struct ceph_inode_info *ci, int mds)
315 {
316         struct ceph_cap *cap;
317         struct rb_node *n = ci->i_caps.rb_node;
318 
319         while (n) {
320                 cap = rb_entry(n, struct ceph_cap, ci_node);
321                 if (mds < cap->mds)
322                         n = n->rb_left;
323                 else if (mds > cap->mds)
324                         n = n->rb_right;
325                 else
326                         return cap;
327         }
328         return NULL;
329 }
330 
331 struct ceph_cap *ceph_get_cap_for_mds(struct ceph_inode_info *ci, int mds)
332 {
333         struct ceph_cap *cap;
334 
335         spin_lock(&ci->i_ceph_lock);
336         cap = __get_cap_for_mds(ci, mds);
337         spin_unlock(&ci->i_ceph_lock);
338         return cap;
339 }
340 
341 /*
342  * Return id of any MDS with a cap, preferably FILE_WR|BUFFER|EXCL, else -1.
343  */
344 static int __ceph_get_cap_mds(struct ceph_inode_info *ci)
345 {
346         struct ceph_cap *cap;
347         int mds = -1;
348         struct rb_node *p;
349 
350         /* prefer mds with WR|BUFFER|EXCL caps */
351         for (p = rb_first(&ci->i_caps); p; p = rb_next(p)) {
352                 cap = rb_entry(p, struct ceph_cap, ci_node);
353                 mds = cap->mds;
354                 if (cap->issued & (CEPH_CAP_FILE_WR |
355                                    CEPH_CAP_FILE_BUFFER |
356                                    CEPH_CAP_FILE_EXCL))
357                         break;
358         }
359         return mds;
360 }
361 
362 int ceph_get_cap_mds(struct inode *inode)
363 {
364         struct ceph_inode_info *ci = ceph_inode(inode);
365         int mds;
366         spin_lock(&ci->i_ceph_lock);
367         mds = __ceph_get_cap_mds(ceph_inode(inode));
368         spin_unlock(&ci->i_ceph_lock);
369         return mds;
370 }
371 
372 /*
373  * Called under i_ceph_lock.
374  */
375 static void __insert_cap_node(struct ceph_inode_info *ci,
376                               struct ceph_cap *new)
377 {
378         struct rb_node **p = &ci->i_caps.rb_node;
379         struct rb_node *parent = NULL;
380         struct ceph_cap *cap = NULL;
381 
382         while (*p) {
383                 parent = *p;
384                 cap = rb_entry(parent, struct ceph_cap, ci_node);
385                 if (new->mds < cap->mds)
386                         p = &(*p)->rb_left;
387                 else if (new->mds > cap->mds)
388                         p = &(*p)->rb_right;
389                 else
390                         BUG();
391         }
392 
393         rb_link_node(&new->ci_node, parent, p);
394         rb_insert_color(&new->ci_node, &ci->i_caps);
395 }
396 
397 /*
398  * (re)set cap hold timeouts, which control the delayed release
399  * of unused caps back to the MDS.  Should be called on cap use.
400  */
401 static void __cap_set_timeouts(struct ceph_mds_client *mdsc,
402                                struct ceph_inode_info *ci)
403 {
404         struct ceph_mount_options *ma = mdsc->fsc->mount_options;
405 
406         ci->i_hold_caps_min = round_jiffies(jiffies +
407                                             ma->caps_wanted_delay_min * HZ);
408         ci->i_hold_caps_max = round_jiffies(jiffies +
409                                             ma->caps_wanted_delay_max * HZ);
410         dout("__cap_set_timeouts %p min %lu max %lu\n", &ci->vfs_inode,
411              ci->i_hold_caps_min - jiffies, ci->i_hold_caps_max - jiffies);
412 }
413 
414 /*
415  * (Re)queue cap at the end of the delayed cap release list.
416  *
417  * If I_FLUSH is set, leave the inode at the front of the list.
418  *
419  * Caller holds i_ceph_lock
420  *    -> we take mdsc->cap_delay_lock
421  */
422 static void __cap_delay_requeue(struct ceph_mds_client *mdsc,
423                                 struct ceph_inode_info *ci)
424 {
425         __cap_set_timeouts(mdsc, ci);
426         dout("__cap_delay_requeue %p flags %d at %lu\n", &ci->vfs_inode,
427              ci->i_ceph_flags, ci->i_hold_caps_max);
428         if (!mdsc->stopping) {
429                 spin_lock(&mdsc->cap_delay_lock);
430                 if (!list_empty(&ci->i_cap_delay_list)) {
431                         if (ci->i_ceph_flags & CEPH_I_FLUSH)
432                                 goto no_change;
433                         list_del_init(&ci->i_cap_delay_list);
434                 }
435                 list_add_tail(&ci->i_cap_delay_list, &mdsc->cap_delay_list);
436 no_change:
437                 spin_unlock(&mdsc->cap_delay_lock);
438         }
439 }
440 
441 /*
442  * Queue an inode for immediate writeback.  Mark inode with I_FLUSH,
443  * indicating we should send a cap message to flush dirty metadata
444  * asap, and move to the front of the delayed cap list.
445  */
446 static void __cap_delay_requeue_front(struct ceph_mds_client *mdsc,
447                                       struct ceph_inode_info *ci)
448 {
449         dout("__cap_delay_requeue_front %p\n", &ci->vfs_inode);
450         spin_lock(&mdsc->cap_delay_lock);
451         ci->i_ceph_flags |= CEPH_I_FLUSH;
452         if (!list_empty(&ci->i_cap_delay_list))
453                 list_del_init(&ci->i_cap_delay_list);
454         list_add(&ci->i_cap_delay_list, &mdsc->cap_delay_list);
455         spin_unlock(&mdsc->cap_delay_lock);
456 }
457 
458 /*
459  * Cancel delayed work on cap.
460  *
461  * Caller must hold i_ceph_lock.
462  */
463 static void __cap_delay_cancel(struct ceph_mds_client *mdsc,
464                                struct ceph_inode_info *ci)
465 {
466         dout("__cap_delay_cancel %p\n", &ci->vfs_inode);
467         if (list_empty(&ci->i_cap_delay_list))
468                 return;
469         spin_lock(&mdsc->cap_delay_lock);
470         list_del_init(&ci->i_cap_delay_list);
471         spin_unlock(&mdsc->cap_delay_lock);
472 }
473 
474 /*
475  * Common issue checks for add_cap, handle_cap_grant.
476  */
477 static void __check_cap_issue(struct ceph_inode_info *ci, struct ceph_cap *cap,
478                               unsigned issued)
479 {
480         unsigned had = __ceph_caps_issued(ci, NULL);
481 
482         /*
483          * Each time we receive FILE_CACHE anew, we increment
484          * i_rdcache_gen.
485          */
486         if ((issued & (CEPH_CAP_FILE_CACHE|CEPH_CAP_FILE_LAZYIO)) &&
487             (had & (CEPH_CAP_FILE_CACHE|CEPH_CAP_FILE_LAZYIO)) == 0)
488                 ci->i_rdcache_gen++;
489 
490         /*
491          * if we are newly issued FILE_SHARED, clear D_COMPLETE; we
492          * don't know what happened to this directory while we didn't
493          * have the cap.
494          */
495         if ((issued & CEPH_CAP_FILE_SHARED) &&
496             (had & CEPH_CAP_FILE_SHARED) == 0) {
497                 ci->i_shared_gen++;
498                 if (S_ISDIR(ci->vfs_inode.i_mode))
499                         ceph_dir_clear_complete(&ci->vfs_inode);
500         }
501 }
502 
503 /*
504  * Add a capability under the given MDS session.
505  *
506  * Caller should hold session snap_rwsem (read) and s_mutex.
507  *
508  * @fmode is the open file mode, if we are opening a file, otherwise
509  * it is < 0.  (This is so we can atomically add the cap and add an
510  * open file reference to it.)
511  */
512 int ceph_add_cap(struct inode *inode,
513                  struct ceph_mds_session *session, u64 cap_id,
514                  int fmode, unsigned issued, unsigned wanted,
515                  unsigned seq, unsigned mseq, u64 realmino, int flags,
516                  struct ceph_cap_reservation *caps_reservation)
517 {
518         struct ceph_mds_client *mdsc = ceph_inode_to_client(inode)->mdsc;
519         struct ceph_inode_info *ci = ceph_inode(inode);
520         struct ceph_cap *new_cap = NULL;
521         struct ceph_cap *cap;
522         int mds = session->s_mds;
523         int actual_wanted;
524 
525         dout("add_cap %p mds%d cap %llx %s seq %d\n", inode,
526              session->s_mds, cap_id, ceph_cap_string(issued), seq);
527 
528         /*
529          * If we are opening the file, include file mode wanted bits
530          * in wanted.
531          */
532         if (fmode >= 0)
533                 wanted |= ceph_caps_for_mode(fmode);
534 
535 retry:
536         spin_lock(&ci->i_ceph_lock);
537         cap = __get_cap_for_mds(ci, mds);
538         if (!cap) {
539                 if (new_cap) {
540                         cap = new_cap;
541                         new_cap = NULL;
542                 } else {
543                         spin_unlock(&ci->i_ceph_lock);
544                         new_cap = get_cap(mdsc, caps_reservation);
545                         if (new_cap == NULL)
546                                 return -ENOMEM;
547                         goto retry;
548                 }
549 
550                 cap->issued = 0;
551                 cap->implemented = 0;
552                 cap->mds = mds;
553                 cap->mds_wanted = 0;
554 
555                 cap->ci = ci;
556                 __insert_cap_node(ci, cap);
557 
558                 /* clear out old exporting info?  (i.e. on cap import) */
559                 if (ci->i_cap_exporting_mds == mds) {
560                         ci->i_cap_exporting_issued = 0;
561                         ci->i_cap_exporting_mseq = 0;
562                         ci->i_cap_exporting_mds = -1;
563                 }
564 
565                 /* add to session cap list */
566                 cap->session = session;
567                 spin_lock(&session->s_cap_lock);
568                 list_add_tail(&cap->session_caps, &session->s_caps);
569                 session->s_nr_caps++;
570                 spin_unlock(&session->s_cap_lock);
571         } else if (new_cap)
572                 ceph_put_cap(mdsc, new_cap);
573 
574         if (!ci->i_snap_realm) {
575                 /*
576                  * add this inode to the appropriate snap realm
577                  */
578                 struct ceph_snap_realm *realm = ceph_lookup_snap_realm(mdsc,
579                                                                realmino);
580                 if (realm) {
581                         ceph_get_snap_realm(mdsc, realm);
582                         spin_lock(&realm->inodes_with_caps_lock);
583                         ci->i_snap_realm = realm;
584                         list_add(&ci->i_snap_realm_item,
585                                  &realm->inodes_with_caps);
586                         spin_unlock(&realm->inodes_with_caps_lock);
587                 } else {
588                         pr_err("ceph_add_cap: couldn't find snap realm %llx\n",
589                                realmino);
590                         WARN_ON(!realm);
591                 }
592         }
593 
594         __check_cap_issue(ci, cap, issued);
595 
596         /*
597          * If we are issued caps we don't want, or the mds' wanted
598          * value appears to be off, queue a check so we'll release
599          * later and/or update the mds wanted value.
600          */
601         actual_wanted = __ceph_caps_wanted(ci);
602         if ((wanted & ~actual_wanted) ||
603             (issued & ~actual_wanted & CEPH_CAP_ANY_WR)) {
604                 dout(" issued %s, mds wanted %s, actual %s, queueing\n",
605                      ceph_cap_string(issued), ceph_cap_string(wanted),
606                      ceph_cap_string(actual_wanted));
607                 __cap_delay_requeue(mdsc, ci);
608         }
609 
610         if (flags & CEPH_CAP_FLAG_AUTH)
611                 ci->i_auth_cap = cap;
612         else if (ci->i_auth_cap == cap)
613                 ci->i_auth_cap = NULL;
614 
615         dout("add_cap inode %p (%llx.%llx) cap %p %s now %s seq %d mds%d\n",
616              inode, ceph_vinop(inode), cap, ceph_cap_string(issued),
617              ceph_cap_string(issued|cap->issued), seq, mds);
618         cap->cap_id = cap_id;
619         cap->issued = issued;
620         cap->implemented |= issued;
621         cap->mds_wanted |= wanted;
622         cap->seq = seq;
623         cap->issue_seq = seq;
624         cap->mseq = mseq;
625         cap->cap_gen = session->s_cap_gen;
626 
627         if (fmode >= 0)
628                 __ceph_get_fmode(ci, fmode);
629         spin_unlock(&ci->i_ceph_lock);
630         wake_up_all(&ci->i_cap_wq);
631         return 0;
632 }
633 
634 /*
635  * Return true if cap has not timed out and belongs to the current
636  * generation of the MDS session (i.e. has not gone 'stale' due to
637  * us losing touch with the mds).
638  */
639 static int __cap_is_valid(struct ceph_cap *cap)
640 {
641         unsigned long ttl;
642         u32 gen;
643 
644         spin_lock(&cap->session->s_gen_ttl_lock);
645         gen = cap->session->s_cap_gen;
646         ttl = cap->session->s_cap_ttl;
647         spin_unlock(&cap->session->s_gen_ttl_lock);
648 
649         if (cap->cap_gen < gen || time_after_eq(jiffies, ttl)) {
650                 dout("__cap_is_valid %p cap %p issued %s "
651                      "but STALE (gen %u vs %u)\n", &cap->ci->vfs_inode,
652                      cap, ceph_cap_string(cap->issued), cap->cap_gen, gen);
653                 return 0;
654         }
655 
656         return 1;
657 }
658 
659 /*
660  * Return set of valid cap bits issued to us.  Note that caps time
661  * out, and may be invalidated in bulk if the client session times out
662  * and session->s_cap_gen is bumped.
663  */
664 int __ceph_caps_issued(struct ceph_inode_info *ci, int *implemented)
665 {
666         int have = ci->i_snap_caps | ci->i_cap_exporting_issued;
667         struct ceph_cap *cap;
668         struct rb_node *p;
669 
670         if (implemented)
671                 *implemented = 0;
672         for (p = rb_first(&ci->i_caps); p; p = rb_next(p)) {
673                 cap = rb_entry(p, struct ceph_cap, ci_node);
674                 if (!__cap_is_valid(cap))
675                         continue;
676                 dout("__ceph_caps_issued %p cap %p issued %s\n",
677                      &ci->vfs_inode, cap, ceph_cap_string(cap->issued));
678                 have |= cap->issued;
679                 if (implemented)
680                         *implemented |= cap->implemented;
681         }
682         return have;
683 }
684 
685 /*
686  * Get cap bits issued by caps other than @ocap
687  */
688 int __ceph_caps_issued_other(struct ceph_inode_info *ci, struct ceph_cap *ocap)
689 {
690         int have = ci->i_snap_caps;
691         struct ceph_cap *cap;
692         struct rb_node *p;
693 
694         for (p = rb_first(&ci->i_caps); p; p = rb_next(p)) {
695                 cap = rb_entry(p, struct ceph_cap, ci_node);
696                 if (cap == ocap)
697                         continue;
698                 if (!__cap_is_valid(cap))
699                         continue;
700                 have |= cap->issued;
701         }
702         return have;
703 }
704 
705 /*
706  * Move a cap to the end of the LRU (oldest caps at list head, newest
707  * at list tail).
708  */
709 static void __touch_cap(struct ceph_cap *cap)
710 {
711         struct ceph_mds_session *s = cap->session;
712 
713         spin_lock(&s->s_cap_lock);
714         if (s->s_cap_iterator == NULL) {
715                 dout("__touch_cap %p cap %p mds%d\n", &cap->ci->vfs_inode, cap,
716                      s->s_mds);
717                 list_move_tail(&cap->session_caps, &s->s_caps);
718         } else {
719                 dout("__touch_cap %p cap %p mds%d NOP, iterating over caps\n",
720                      &cap->ci->vfs_inode, cap, s->s_mds);
721         }
722         spin_unlock(&s->s_cap_lock);
723 }
724 
725 /*
726  * Check if we hold the given mask.  If so, move the cap(s) to the
727  * front of their respective LRUs.  (This is the preferred way for
728  * callers to check for caps they want.)
729  */
730 int __ceph_caps_issued_mask(struct ceph_inode_info *ci, int mask, int touch)
731 {
732         struct ceph_cap *cap;
733         struct rb_node *p;
734         int have = ci->i_snap_caps;
735 
736         if ((have & mask) == mask) {
737                 dout("__ceph_caps_issued_mask %p snap issued %s"
738                      " (mask %s)\n", &ci->vfs_inode,
739                      ceph_cap_string(have),
740                      ceph_cap_string(mask));
741                 return 1;
742         }
743 
744         for (p = rb_first(&ci->i_caps); p; p = rb_next(p)) {
745                 cap = rb_entry(p, struct ceph_cap, ci_node);
746                 if (!__cap_is_valid(cap))
747                         continue;
748                 if ((cap->issued & mask) == mask) {
749                         dout("__ceph_caps_issued_mask %p cap %p issued %s"
750                              " (mask %s)\n", &ci->vfs_inode, cap,
751                              ceph_cap_string(cap->issued),
752                              ceph_cap_string(mask));
753                         if (touch)
754                                 __touch_cap(cap);
755                         return 1;
756                 }
757 
758                 /* does a combination of caps satisfy mask? */
759                 have |= cap->issued;
760                 if ((have & mask) == mask) {
761                         dout("__ceph_caps_issued_mask %p combo issued %s"
762                              " (mask %s)\n", &ci->vfs_inode,
763                              ceph_cap_string(cap->issued),
764                              ceph_cap_string(mask));
765                         if (touch) {
766                                 struct rb_node *q;
767 
768                                 /* touch this + preceding caps */
769                                 __touch_cap(cap);
770                                 for (q = rb_first(&ci->i_caps); q != p;
771                                      q = rb_next(q)) {
772                                         cap = rb_entry(q, struct ceph_cap,
773                                                        ci_node);
774                                         if (!__cap_is_valid(cap))
775                                                 continue;
776                                         __touch_cap(cap);
777                                 }
778                         }
779                         return 1;
780                 }
781         }
782 
783         return 0;
784 }
785 
786 /*
787  * Return true if mask caps are currently being revoked by an MDS.
788  */
789 int ceph_caps_revoking(struct ceph_inode_info *ci, int mask)
790 {
791         struct inode *inode = &ci->vfs_inode;
792         struct ceph_cap *cap;
793         struct rb_node *p;
794         int ret = 0;
795 
796         spin_lock(&ci->i_ceph_lock);
797         for (p = rb_first(&ci->i_caps); p; p = rb_next(p)) {
798                 cap = rb_entry(p, struct ceph_cap, ci_node);
799                 if (__cap_is_valid(cap) &&
800                     (cap->implemented & ~cap->issued & mask)) {
801                         ret = 1;
802                         break;
803                 }
804         }
805         spin_unlock(&ci->i_ceph_lock);
806         dout("ceph_caps_revoking %p %s = %d\n", inode,
807              ceph_cap_string(mask), ret);
808         return ret;
809 }
810 
811 int __ceph_caps_used(struct ceph_inode_info *ci)
812 {
813         int used = 0;
814         if (ci->i_pin_ref)
815                 used |= CEPH_CAP_PIN;
816         if (ci->i_rd_ref)
817                 used |= CEPH_CAP_FILE_RD;
818         if (ci->i_rdcache_ref || ci->vfs_inode.i_data.nrpages)
819                 used |= CEPH_CAP_FILE_CACHE;
820         if (ci->i_wr_ref)
821                 used |= CEPH_CAP_FILE_WR;
822         if (ci->i_wb_ref || ci->i_wrbuffer_ref)
823                 used |= CEPH_CAP_FILE_BUFFER;
824         return used;
825 }
826 
827 /*
828  * wanted, by virtue of open file modes
829  */
830 int __ceph_caps_file_wanted(struct ceph_inode_info *ci)
831 {
832         int want = 0;
833         int mode;
834         for (mode = 0; mode < CEPH_FILE_MODE_NUM; mode++)
835                 if (ci->i_nr_by_mode[mode])
836                         want |= ceph_caps_for_mode(mode);
837         return want;
838 }
839 
840 /*
841  * Return caps we have registered with the MDS(s) as 'wanted'.
842  */
843 int __ceph_caps_mds_wanted(struct ceph_inode_info *ci)
844 {
845         struct ceph_cap *cap;
846         struct rb_node *p;
847         int mds_wanted = 0;
848 
849         for (p = rb_first(&ci->i_caps); p; p = rb_next(p)) {
850                 cap = rb_entry(p, struct ceph_cap, ci_node);
851                 if (!__cap_is_valid(cap))
852                         continue;
853                 mds_wanted |= cap->mds_wanted;
854         }
855         return mds_wanted;
856 }
857 
858 /*
859  * called under i_ceph_lock
860  */
861 static int __ceph_is_any_caps(struct ceph_inode_info *ci)
862 {
863         return !RB_EMPTY_ROOT(&ci->i_caps) || ci->i_cap_exporting_mds >= 0;
864 }
865 
866 /*
867  * Remove a cap.  Take steps to deal with a racing iterate_session_caps.
868  *
869  * caller should hold i_ceph_lock.
870  * caller will not hold session s_mutex if called from destroy_inode.
871  */
872 void __ceph_remove_cap(struct ceph_cap *cap)
873 {
874         struct ceph_mds_session *session = cap->session;
875         struct ceph_inode_info *ci = cap->ci;
876         struct ceph_mds_client *mdsc =
877                 ceph_sb_to_client(ci->vfs_inode.i_sb)->mdsc;
878         int removed = 0;
879 
880         dout("__ceph_remove_cap %p from %p\n", cap, &ci->vfs_inode);
881 
882         /* remove from session list */
883         spin_lock(&session->s_cap_lock);
884         if (session->s_cap_iterator == cap) {
885                 /* not yet, we are iterating over this very cap */
886                 dout("__ceph_remove_cap  delaying %p removal from session %p\n",
887                      cap, cap->session);
888         } else {
889                 list_del_init(&cap->session_caps);
890                 session->s_nr_caps--;
891                 cap->session = NULL;
892                 removed = 1;
893         }
894         /* protect backpointer with s_cap_lock: see iterate_session_caps */
895         cap->ci = NULL;
896         spin_unlock(&session->s_cap_lock);
897 
898         /* remove from inode list */
899         rb_erase(&cap->ci_node, &ci->i_caps);
900         if (ci->i_auth_cap == cap)
901                 ci->i_auth_cap = NULL;
902 
903         if (removed)
904                 ceph_put_cap(mdsc, cap);
905 
906         if (!__ceph_is_any_caps(ci) && ci->i_snap_realm) {
907                 struct ceph_snap_realm *realm = ci->i_snap_realm;
908                 spin_lock(&realm->inodes_with_caps_lock);
909                 list_del_init(&ci->i_snap_realm_item);
910                 ci->i_snap_realm_counter++;
911                 ci->i_snap_realm = NULL;
912                 spin_unlock(&realm->inodes_with_caps_lock);
913                 ceph_put_snap_realm(mdsc, realm);
914         }
915         if (!__ceph_is_any_real_caps(ci))
916                 __cap_delay_cancel(mdsc, ci);
917 }
918 
919 /*
920  * Build and send a cap message to the given MDS.
921  *
922  * Caller should be holding s_mutex.
923  */
924 static int send_cap_msg(struct ceph_mds_session *session,
925                         u64 ino, u64 cid, int op,
926                         int caps, int wanted, int dirty,
927                         u32 seq, u64 flush_tid, u32 issue_seq, u32 mseq,
928                         u64 size, u64 max_size,
929                         struct timespec *mtime, struct timespec *atime,
930                         u64 time_warp_seq,
931                         uid_t uid, gid_t gid, umode_t mode,
932                         u64 xattr_version,
933                         struct ceph_buffer *xattrs_buf,
934                         u64 follows)
935 {
936         struct ceph_mds_caps *fc;
937         struct ceph_msg *msg;
938 
939         dout("send_cap_msg %s %llx %llx caps %s wanted %s dirty %s"
940              " seq %u/%u mseq %u follows %lld size %llu/%llu"
941              " xattr_ver %llu xattr_len %d\n", ceph_cap_op_name(op),
942              cid, ino, ceph_cap_string(caps), ceph_cap_string(wanted),
943              ceph_cap_string(dirty),
944              seq, issue_seq, mseq, follows, size, max_size,
945              xattr_version, xattrs_buf ? (int)xattrs_buf->vec.iov_len : 0);
946 
947         msg = ceph_msg_new(CEPH_MSG_CLIENT_CAPS, sizeof(*fc), GFP_NOFS, false);
948         if (!msg)
949                 return -ENOMEM;
950 
951         msg->hdr.tid = cpu_to_le64(flush_tid);
952 
953         fc = msg->front.iov_base;
954         memset(fc, 0, sizeof(*fc));
955 
956         fc->cap_id = cpu_to_le64(cid);
957         fc->op = cpu_to_le32(op);
958         fc->seq = cpu_to_le32(seq);
959         fc->issue_seq = cpu_to_le32(issue_seq);
960         fc->migrate_seq = cpu_to_le32(mseq);
961         fc->caps = cpu_to_le32(caps);
962         fc->wanted = cpu_to_le32(wanted);
963         fc->dirty = cpu_to_le32(dirty);
964         fc->ino = cpu_to_le64(ino);
965         fc->snap_follows = cpu_to_le64(follows);
966 
967         fc->size = cpu_to_le64(size);
968         fc->max_size = cpu_to_le64(max_size);
969         if (mtime)
970                 ceph_encode_timespec(&fc->mtime, mtime);
971         if (atime)
972                 ceph_encode_timespec(&fc->atime, atime);
973         fc->time_warp_seq = cpu_to_le32(time_warp_seq);
974 
975         fc->uid = cpu_to_le32(uid);
976         fc->gid = cpu_to_le32(gid);
977         fc->mode = cpu_to_le32(mode);
978 
979         fc->xattr_version = cpu_to_le64(xattr_version);
980         if (xattrs_buf) {
981                 msg->middle = ceph_buffer_get(xattrs_buf);
982                 fc->xattr_len = cpu_to_le32(xattrs_buf->vec.iov_len);
983                 msg->hdr.middle_len = cpu_to_le32(xattrs_buf->vec.iov_len);
984         }
985 
986         ceph_con_send(&session->s_con, msg);
987         return 0;
988 }
989 
990 static void __queue_cap_release(struct ceph_mds_session *session,
991                                 u64 ino, u64 cap_id, u32 migrate_seq,
992                                 u32 issue_seq)
993 {
994         struct ceph_msg *msg;
995         struct ceph_mds_cap_release *head;
996         struct ceph_mds_cap_item *item;
997 
998         spin_lock(&session->s_cap_lock);
999         BUG_ON(!session->s_num_cap_releases);
1000         msg = list_first_entry(&session->s_cap_releases,
1001                                struct ceph_msg, list_head);
1002 
1003         dout(" adding %llx release to mds%d msg %p (%d left)\n",
1004              ino, session->s_mds, msg, session->s_num_cap_releases);
1005 
1006         BUG_ON(msg->front.iov_len + sizeof(*item) > PAGE_CACHE_SIZE);
1007         head = msg->front.iov_base;
1008         head->num = cpu_to_le32(le32_to_cpu(head->num) + 1);
1009         item = msg->front.iov_base + msg->front.iov_len;
1010         item->ino = cpu_to_le64(ino);
1011         item->cap_id = cpu_to_le64(cap_id);
1012         item->migrate_seq = cpu_to_le32(migrate_seq);
1013         item->seq = cpu_to_le32(issue_seq);
1014 
1015         session->s_num_cap_releases--;
1016 
1017         msg->front.iov_len += sizeof(*item);
1018         if (le32_to_cpu(head->num) == CEPH_CAPS_PER_RELEASE) {
1019                 dout(" release msg %p full\n", msg);
1020                 list_move_tail(&msg->list_head, &session->s_cap_releases_done);
1021         } else {
1022                 dout(" release msg %p at %d/%d (%d)\n", msg,
1023                      (int)le32_to_cpu(head->num),
1024                      (int)CEPH_CAPS_PER_RELEASE,
1025                      (int)msg->front.iov_len);
1026         }
1027         spin_unlock(&session->s_cap_lock);
1028 }
1029 
1030 /*
1031  * Queue cap releases when an inode is dropped from our cache.  Since
1032  * inode is about to be destroyed, there is no need for i_ceph_lock.
1033  */
1034 void ceph_queue_caps_release(struct inode *inode)
1035 {
1036         struct ceph_inode_info *ci = ceph_inode(inode);
1037         struct rb_node *p;
1038 
1039         p = rb_first(&ci->i_caps);
1040         while (p) {
1041                 struct ceph_cap *cap = rb_entry(p, struct ceph_cap, ci_node);
1042                 struct ceph_mds_session *session = cap->session;
1043 
1044                 __queue_cap_release(session, ceph_ino(inode), cap->cap_id,
1045                                     cap->mseq, cap->issue_seq);
1046                 p = rb_next(p);
1047                 __ceph_remove_cap(cap);
1048         }
1049 }
1050 
1051 /*
1052  * Send a cap msg on the given inode.  Update our caps state, then
1053  * drop i_ceph_lock and send the message.
1054  *
1055  * Make note of max_size reported/requested from mds, revoked caps
1056  * that have now been implemented.
1057  *
1058  * Make half-hearted attempt ot to invalidate page cache if we are
1059  * dropping RDCACHE.  Note that this will leave behind locked pages
1060  * that we'll then need to deal with elsewhere.
1061  *
1062  * Return non-zero if delayed release, or we experienced an error
1063  * such that the caller should requeue + retry later.
1064  *
1065  * called with i_ceph_lock, then drops it.
1066  * caller should hold snap_rwsem (read), s_mutex.
1067  */
1068 static int __send_cap(struct ceph_mds_client *mdsc, struct ceph_cap *cap,
1069                       int op, int used, int want, int retain, int flushing,
1070                       unsigned *pflush_tid)
1071         __releases(cap->ci->i_ceph_lock)
1072 {
1073         struct ceph_inode_info *ci = cap->ci;
1074         struct inode *inode = &ci->vfs_inode;
1075         u64 cap_id = cap->cap_id;
1076         int held, revoking, dropping, keep;
1077         u64 seq, issue_seq, mseq, time_warp_seq, follows;
1078         u64 size, max_size;
1079         struct timespec mtime, atime;
1080         int wake = 0;
1081         umode_t mode;
1082         uid_t uid;
1083         gid_t gid;
1084         struct ceph_mds_session *session;
1085         u64 xattr_version = 0;
1086         struct ceph_buffer *xattr_blob = NULL;
1087         int delayed = 0;
1088         u64 flush_tid = 0;
1089         int i;
1090         int ret;
1091 
1092         held = cap->issued | cap->implemented;
1093         revoking = cap->implemented & ~cap->issued;
1094         retain &= ~revoking;
1095         dropping = cap->issued & ~retain;
1096 
1097         dout("__send_cap %p cap %p session %p %s -> %s (revoking %s)\n",
1098              inode, cap, cap->session,
1099              ceph_cap_string(held), ceph_cap_string(held & retain),
1100              ceph_cap_string(revoking));
1101         BUG_ON((retain & CEPH_CAP_PIN) == 0);
1102 
1103         session = cap->session;
1104 
1105         /* don't release wanted unless we've waited a bit. */
1106         if ((ci->i_ceph_flags & CEPH_I_NODELAY) == 0 &&
1107             time_before(jiffies, ci->i_hold_caps_min)) {
1108                 dout(" delaying issued %s -> %s, wanted %s -> %s on send\n",
1109                      ceph_cap_string(cap->issued),
1110                      ceph_cap_string(cap->issued & retain),
1111                      ceph_cap_string(cap->mds_wanted),
1112                      ceph_cap_string(want));
1113                 want |= cap->mds_wanted;
1114                 retain |= cap->issued;
1115                 delayed = 1;
1116         }
1117         ci->i_ceph_flags &= ~(CEPH_I_NODELAY | CEPH_I_FLUSH);
1118 
1119         cap->issued &= retain;  /* drop bits we don't want */
1120         if (cap->implemented & ~cap->issued) {
1121                 /*
1122                  * Wake up any waiters on wanted -> needed transition.
1123                  * This is due to the weird transition from buffered
1124                  * to sync IO... we need to flush dirty pages _before_
1125                  * allowing sync writes to avoid reordering.
1126                  */
1127                 wake = 1;
1128         }
1129         cap->implemented &= cap->issued | used;
1130         cap->mds_wanted = want;
1131 
1132         if (flushing) {
1133                 /*
1134                  * assign a tid for flush operations so we can avoid
1135                  * flush1 -> dirty1 -> flush2 -> flushack1 -> mark
1136                  * clean type races.  track latest tid for every bit
1137                  * so we can handle flush AxFw, flush Fw, and have the
1138                  * first ack clean Ax.
1139                  */
1140                 flush_tid = ++ci->i_cap_flush_last_tid;
1141                 if (pflush_tid)
1142                         *pflush_tid = flush_tid;
1143                 dout(" cap_flush_tid %d\n", (int)flush_tid);
1144                 for (i = 0; i < CEPH_CAP_BITS; i++)
1145                         if (flushing & (1 << i))
1146                                 ci->i_cap_flush_tid[i] = flush_tid;
1147 
1148                 follows = ci->i_head_snapc->seq;
1149         } else {
1150                 follows = 0;
1151         }
1152 
1153         keep = cap->implemented;
1154         seq = cap->seq;
1155         issue_seq = cap->issue_seq;
1156         mseq = cap->mseq;
1157         size = inode->i_size;
1158         ci->i_reported_size = size;
1159         max_size = ci->i_wanted_max_size;
1160         ci->i_requested_max_size = max_size;
1161         mtime = inode->i_mtime;
1162         atime = inode->i_atime;
1163         time_warp_seq = ci->i_time_warp_seq;
1164         uid = inode->i_uid;
1165         gid = inode->i_gid;
1166         mode = inode->i_mode;
1167 
1168         if (flushing & CEPH_CAP_XATTR_EXCL) {
1169                 __ceph_build_xattrs_blob(ci);
1170                 xattr_blob = ci->i_xattrs.blob;
1171                 xattr_version = ci->i_xattrs.version;
1172         }
1173 
1174         spin_unlock(&ci->i_ceph_lock);
1175 
1176         ret = send_cap_msg(session, ceph_vino(inode).ino, cap_id,
1177                 op, keep, want, flushing, seq, flush_tid, issue_seq, mseq,
1178                 size, max_size, &mtime, &atime, time_warp_seq,
1179                 uid, gid, mode, xattr_version, xattr_blob,
1180                 follows);
1181         if (ret < 0) {
1182                 dout("error sending cap msg, must requeue %p\n", inode);
1183                 delayed = 1;
1184         }
1185 
1186         if (wake)
1187                 wake_up_all(&ci->i_cap_wq);
1188 
1189         return delayed;
1190 }
1191 
1192 /*
1193  * When a snapshot is taken, clients accumulate dirty metadata on
1194  * inodes with capabilities in ceph_cap_snaps to describe the file
1195  * state at the time the snapshot was taken.  This must be flushed
1196  * asynchronously back to the MDS once sync writes complete and dirty
1197  * data is written out.
1198  *
1199  * Unless @again is true, skip cap_snaps that were already sent to
1200  * the MDS (i.e., during this session).
1201  *
1202  * Called under i_ceph_lock.  Takes s_mutex as needed.
1203  */
1204 void __ceph_flush_snaps(struct ceph_inode_info *ci,
1205                         struct ceph_mds_session **psession,
1206                         int again)
1207                 __releases(ci->i_ceph_lock)
1208                 __acquires(ci->i_ceph_lock)
1209 {
1210         struct inode *inode = &ci->vfs_inode;
1211         int mds;
1212         struct ceph_cap_snap *capsnap;
1213         u32 mseq;
1214         struct ceph_mds_client *mdsc = ceph_inode_to_client(inode)->mdsc;
1215         struct ceph_mds_session *session = NULL; /* if session != NULL, we hold
1216                                                     session->s_mutex */
1217         u64 next_follows = 0;  /* keep track of how far we've gotten through the
1218                              i_cap_snaps list, and skip these entries next time
1219                              around to avoid an infinite loop */
1220 
1221         if (psession)
1222                 session = *psession;
1223 
1224         dout("__flush_snaps %p\n", inode);
1225 retry:
1226         list_for_each_entry(capsnap, &ci->i_cap_snaps, ci_item) {
1227                 /* avoid an infiniute loop after retry */
1228                 if (capsnap->follows < next_follows)
1229                         continue;
1230                 /*
1231                  * we need to wait for sync writes to complete and for dirty
1232                  * pages to be written out.
1233                  */
1234                 if (capsnap->dirty_pages || capsnap->writing)
1235                         break;
1236 
1237                 /*
1238                  * if cap writeback already occurred, we should have dropped
1239                  * the capsnap in ceph_put_wrbuffer_cap_refs.
1240                  */
1241                 BUG_ON(capsnap->dirty == 0);
1242 
1243                 /* pick mds, take s_mutex */
1244                 if (ci->i_auth_cap == NULL) {
1245                         dout("no auth cap (migrating?), doing nothing\n");
1246                         goto out;
1247                 }
1248 
1249                 /* only flush each capsnap once */
1250                 if (!again && !list_empty(&capsnap->flushing_item)) {
1251                         dout("already flushed %p, skipping\n", capsnap);
1252                         continue;
1253                 }
1254 
1255                 mds = ci->i_auth_cap->session->s_mds;
1256                 mseq = ci->i_auth_cap->mseq;
1257 
1258                 if (session && session->s_mds != mds) {
1259                         dout("oops, wrong session %p mutex\n", session);
1260                         mutex_unlock(&session->s_mutex);
1261                         ceph_put_mds_session(session);
1262                         session = NULL;
1263                 }
1264                 if (!session) {
1265                         spin_unlock(&ci->i_ceph_lock);
1266                         mutex_lock(&mdsc->mutex);
1267                         session = __ceph_lookup_mds_session(mdsc, mds);
1268                         mutex_unlock(&mdsc->mutex);
1269                         if (session) {
1270                                 dout("inverting session/ino locks on %p\n",
1271                                      session);
1272                                 mutex_lock(&session->s_mutex);
1273                         }
1274                         /*
1275                          * if session == NULL, we raced against a cap
1276                          * deletion or migration.  retry, and we'll
1277                          * get a better @mds value next time.
1278                          */
1279                         spin_lock(&ci->i_ceph_lock);
1280                         goto retry;
1281                 }
1282 
1283                 capsnap->flush_tid = ++ci->i_cap_flush_last_tid;
1284                 atomic_inc(&capsnap->nref);
1285                 if (!list_empty(&capsnap->flushing_item))
1286                         list_del_init(&capsnap->flushing_item);
1287                 list_add_tail(&capsnap->flushing_item,
1288                               &session->s_cap_snaps_flushing);
1289                 spin_unlock(&ci->i_ceph_lock);
1290 
1291                 dout("flush_snaps %p cap_snap %p follows %lld tid %llu\n",
1292                      inode, capsnap, capsnap->follows, capsnap->flush_tid);
1293                 send_cap_msg(session, ceph_vino(inode).ino, 0,
1294                              CEPH_CAP_OP_FLUSHSNAP, capsnap->issued, 0,
1295                              capsnap->dirty, 0, capsnap->flush_tid, 0, mseq,
1296                              capsnap->size, 0,
1297                              &capsnap->mtime, &capsnap->atime,
1298                              capsnap->time_warp_seq,
1299                              capsnap->uid, capsnap->gid, capsnap->mode,
1300                              capsnap->xattr_version, capsnap->xattr_blob,
1301                              capsnap->follows);
1302 
1303                 next_follows = capsnap->follows + 1;
1304                 ceph_put_cap_snap(capsnap);
1305 
1306                 spin_lock(&ci->i_ceph_lock);
1307                 goto retry;
1308         }
1309 
1310         /* we flushed them all; remove this inode from the queue */
1311         spin_lock(&mdsc->snap_flush_lock);
1312         list_del_init(&ci->i_snap_flush_item);
1313         spin_unlock(&mdsc->snap_flush_lock);
1314 
1315 out:
1316         if (psession)
1317                 *psession = session;
1318         else if (session) {
1319                 mutex_unlock(&session->s_mutex);
1320                 ceph_put_mds_session(session);
1321         }
1322 }
1323 
1324 static void ceph_flush_snaps(struct ceph_inode_info *ci)
1325 {
1326         spin_lock(&ci->i_ceph_lock);
1327         __ceph_flush_snaps(ci, NULL, 0);
1328         spin_unlock(&ci->i_ceph_lock);
1329 }
1330 
1331 /*
1332  * Mark caps dirty.  If inode is newly dirty, return the dirty flags.
1333  * Caller is then responsible for calling __mark_inode_dirty with the
1334  * returned flags value.
1335  */
1336 int __ceph_mark_dirty_caps(struct ceph_inode_info *ci, int mask)
1337 {
1338         struct ceph_mds_client *mdsc =
1339                 ceph_sb_to_client(ci->vfs_inode.i_sb)->mdsc;
1340         struct inode *inode = &ci->vfs_inode;
1341         int was = ci->i_dirty_caps;
1342         int dirty = 0;
1343 
1344         dout("__mark_dirty_caps %p %s dirty %s -> %s\n", &ci->vfs_inode,
1345              ceph_cap_string(mask), ceph_cap_string(was),
1346              ceph_cap_string(was | mask));
1347         ci->i_dirty_caps |= mask;
1348         if (was == 0) {
1349                 if (!ci->i_head_snapc)
1350                         ci->i_head_snapc = ceph_get_snap_context(
1351                                 ci->i_snap_realm->cached_context);
1352                 dout(" inode %p now dirty snapc %p auth cap %p\n",
1353                      &ci->vfs_inode, ci->i_head_snapc, ci->i_auth_cap);
1354                 BUG_ON(!list_empty(&ci->i_dirty_item));
1355                 spin_lock(&mdsc->cap_dirty_lock);
1356                 if (ci->i_auth_cap)
1357                         list_add(&ci->i_dirty_item, &mdsc->cap_dirty);
1358                 else
1359                         list_add(&ci->i_dirty_item,
1360                                  &mdsc->cap_dirty_migrating);
1361                 spin_unlock(&mdsc->cap_dirty_lock);
1362                 if (ci->i_flushing_caps == 0) {
1363                         ihold(inode);
1364                         dirty |= I_DIRTY_SYNC;
1365                 }
1366         }
1367         BUG_ON(list_empty(&ci->i_dirty_item));
1368         if (((was | ci->i_flushing_caps) & CEPH_CAP_FILE_BUFFER) &&
1369             (mask & CEPH_CAP_FILE_BUFFER))
1370                 dirty |= I_DIRTY_DATASYNC;
1371         __cap_delay_requeue(mdsc, ci);
1372         return dirty;
1373 }
1374 
1375 /*
1376  * Add dirty inode to the flushing list.  Assigned a seq number so we
1377  * can wait for caps to flush without starving.
1378  *
1379  * Called under i_ceph_lock.
1380  */
1381 static int __mark_caps_flushing(struct inode *inode,
1382                                  struct ceph_mds_session *session)
1383 {
1384         struct ceph_mds_client *mdsc = ceph_sb_to_client(inode->i_sb)->mdsc;
1385         struct ceph_inode_info *ci = ceph_inode(inode);
1386         int flushing;
1387 
1388         BUG_ON(ci->i_dirty_caps == 0);
1389         BUG_ON(list_empty(&ci->i_dirty_item));
1390 
1391         flushing = ci->i_dirty_caps;
1392         dout("__mark_caps_flushing flushing %s, flushing_caps %s -> %s\n",
1393              ceph_cap_string(flushing),
1394              ceph_cap_string(ci->i_flushing_caps),
1395              ceph_cap_string(ci->i_flushing_caps | flushing));
1396         ci->i_flushing_caps |= flushing;
1397         ci->i_dirty_caps = 0;
1398         dout(" inode %p now !dirty\n", inode);
1399 
1400         spin_lock(&mdsc->cap_dirty_lock);
1401         list_del_init(&ci->i_dirty_item);
1402 
1403         ci->i_cap_flush_seq = ++mdsc->cap_flush_seq;
1404         if (list_empty(&ci->i_flushing_item)) {
1405                 list_add_tail(&ci->i_flushing_item, &session->s_cap_flushing);
1406                 mdsc->num_cap_flushing++;
1407                 dout(" inode %p now flushing seq %lld\n", inode,
1408                      ci->i_cap_flush_seq);
1409         } else {
1410                 list_move_tail(&ci->i_flushing_item, &session->s_cap_flushing);
1411                 dout(" inode %p now flushing (more) seq %lld\n", inode,
1412                      ci->i_cap_flush_seq);
1413         }
1414         spin_unlock(&mdsc->cap_dirty_lock);
1415 
1416         return flushing;
1417 }
1418 
1419 /*
1420  * try to invalidate mapping pages without blocking.
1421  */
1422 static int try_nonblocking_invalidate(struct inode *inode)
1423 {
1424         struct ceph_inode_info *ci = ceph_inode(inode);
1425         u32 invalidating_gen = ci->i_rdcache_gen;
1426 
1427         spin_unlock(&ci->i_ceph_lock);
1428         invalidate_mapping_pages(&inode->i_data, 0, -1);
1429         spin_lock(&ci->i_ceph_lock);
1430 
1431         if (inode->i_data.nrpages == 0 &&
1432             invalidating_gen == ci->i_rdcache_gen) {
1433                 /* success. */
1434                 dout("try_nonblocking_invalidate %p success\n", inode);
1435                 /* save any racing async invalidate some trouble */
1436                 ci->i_rdcache_revoking = ci->i_rdcache_gen - 1;
1437                 return 0;
1438         }
1439         dout("try_nonblocking_invalidate %p failed\n", inode);
1440         return -1;
1441 }
1442 
1443 /*
1444  * Swiss army knife function to examine currently used and wanted
1445  * versus held caps.  Release, flush, ack revoked caps to mds as
1446  * appropriate.
1447  *
1448  *  CHECK_CAPS_NODELAY - caller is delayed work and we should not delay
1449  *    cap release further.
1450  *  CHECK_CAPS_AUTHONLY - we should only check the auth cap
1451  *  CHECK_CAPS_FLUSH - we should flush any dirty caps immediately, without
1452  *    further delay.
1453  */
1454 void ceph_check_caps(struct ceph_inode_info *ci, int flags,
1455                      struct ceph_mds_session *session)
1456 {
1457         struct ceph_fs_client *fsc = ceph_inode_to_client(&ci->vfs_inode);
1458         struct ceph_mds_client *mdsc = fsc->mdsc;
1459         struct inode *inode = &ci->vfs_inode;
1460         struct ceph_cap *cap;
1461         int file_wanted, used;
1462         int took_snap_rwsem = 0;             /* true if mdsc->snap_rwsem held */
1463         int issued, implemented, want, retain, revoking, flushing = 0;
1464         int mds = -1;   /* keep track of how far we've gone through i_caps list
1465                            to avoid an infinite loop on retry */
1466         struct rb_node *p;
1467         int tried_invalidate = 0;
1468         int delayed = 0, sent = 0, force_requeue = 0, num;
1469         int queue_invalidate = 0;
1470         int is_delayed = flags & CHECK_CAPS_NODELAY;
1471 
1472         /* if we are unmounting, flush any unused caps immediately. */
1473         if (mdsc->stopping)
1474                 is_delayed = 1;
1475 
1476         spin_lock(&ci->i_ceph_lock);
1477 
1478         if (ci->i_ceph_flags & CEPH_I_FLUSH)
1479                 flags |= CHECK_CAPS_FLUSH;
1480 
1481         /* flush snaps first time around only */
1482         if (!list_empty(&ci->i_cap_snaps))
1483                 __ceph_flush_snaps(ci, &session, 0);
1484         goto retry_locked;
1485 retry:
1486         spin_lock(&ci->i_ceph_lock);
1487 retry_locked:
1488         file_wanted = __ceph_caps_file_wanted(ci);
1489         used = __ceph_caps_used(ci);
1490         want = file_wanted | used;
1491         issued = __ceph_caps_issued(ci, &implemented);
1492         revoking = implemented & ~issued;
1493 
1494         retain = want | CEPH_CAP_PIN;
1495         if (!mdsc->stopping && inode->i_nlink > 0) {
1496                 if (want) {
1497                         retain |= CEPH_CAP_ANY;       /* be greedy */
1498                 } else {
1499                         retain |= CEPH_CAP_ANY_SHARED;
1500                         /*
1501                          * keep RD only if we didn't have the file open RW,
1502                          * because then the mds would revoke it anyway to
1503                          * journal max_size=0.
1504                          */
1505                         if (ci->i_max_size == 0)
1506                                 retain |= CEPH_CAP_ANY_RD;
1507                 }
1508         }
1509 
1510         dout("check_caps %p file_want %s used %s dirty %s flushing %s"
1511              " issued %s revoking %s retain %s %s%s%s\n", inode,
1512              ceph_cap_string(file_wanted),
1513              ceph_cap_string(used), ceph_cap_string(ci->i_dirty_caps),
1514              ceph_cap_string(ci->i_flushing_caps),
1515              ceph_cap_string(issued), ceph_cap_string(revoking),
1516              ceph_cap_string(retain),
1517              (flags & CHECK_CAPS_AUTHONLY) ? " AUTHONLY" : "",
1518              (flags & CHECK_CAPS_NODELAY) ? " NODELAY" : "",
1519              (flags & CHECK_CAPS_FLUSH) ? " FLUSH" : "");
1520 
1521         /*
1522          * If we no longer need to hold onto old our caps, and we may
1523          * have cached pages, but don't want them, then try to invalidate.
1524          * If we fail, it's because pages are locked.... try again later.
1525          */
1526         if ((!is_delayed || mdsc->stopping) &&
1527             ci->i_wrbuffer_ref == 0 &&               /* no dirty pages... */
1528             inode->i_data.nrpages &&                 /* have cached pages */
1529             (file_wanted == 0 ||                     /* no open files */
1530              (revoking & (CEPH_CAP_FILE_CACHE|
1531                           CEPH_CAP_FILE_LAZYIO))) && /*  or revoking cache */
1532             !tried_invalidate) {
1533                 dout("check_caps trying to invalidate on %p\n", inode);
1534                 if (try_nonblocking_invalidate(inode) < 0) {
1535                         if (revoking & (CEPH_CAP_FILE_CACHE|
1536                                         CEPH_CAP_FILE_LAZYIO)) {
1537                                 dout("check_caps queuing invalidate\n");
1538                                 queue_invalidate = 1;
1539                                 ci->i_rdcache_revoking = ci->i_rdcache_gen;
1540                         } else {
1541                                 dout("check_caps failed to invalidate pages\n");
1542                                 /* we failed to invalidate pages.  check these
1543                                    caps again later. */
1544                                 force_requeue = 1;
1545                                 __cap_set_timeouts(mdsc, ci);
1546                         }
1547                 }
1548                 tried_invalidate = 1;
1549                 goto retry_locked;
1550         }
1551 
1552         num = 0;
1553         for (p = rb_first(&ci->i_caps); p; p = rb_next(p)) {
1554                 cap = rb_entry(p, struct ceph_cap, ci_node);
1555                 num++;
1556 
1557                 /* avoid looping forever */
1558                 if (mds >= cap->mds ||
1559                     ((flags & CHECK_CAPS_AUTHONLY) && cap != ci->i_auth_cap))
1560                         continue;
1561 
1562                 /* NOTE: no side-effects allowed, until we take s_mutex */
1563 
1564                 revoking = cap->implemented & ~cap->issued;
1565                 dout(" mds%d cap %p issued %s implemented %s revoking %s\n",
1566                      cap->mds, cap, ceph_cap_string(cap->issued),
1567                      ceph_cap_string(cap->implemented),
1568                      ceph_cap_string(revoking));
1569 
1570                 if (cap == ci->i_auth_cap &&
1571                     (cap->issued & CEPH_CAP_FILE_WR)) {
1572                         /* request larger max_size from MDS? */
1573                         if (ci->i_wanted_max_size > ci->i_max_size &&
1574                             ci->i_wanted_max_size > ci->i_requested_max_size) {
1575                                 dout("requesting new max_size\n");
1576                                 goto ack;
1577                         }
1578 
1579                         /* approaching file_max? */
1580                         if ((inode->i_size << 1) >= ci->i_max_size &&
1581                             (ci->i_reported_size << 1) < ci->i_max_size) {
1582                                 dout("i_size approaching max_size\n");
1583                                 goto ack;
1584                         }
1585                 }
1586                 /* flush anything dirty? */
1587                 if (cap == ci->i_auth_cap && (flags & CHECK_CAPS_FLUSH) &&
1588                     ci->i_dirty_caps) {
1589                         dout("flushing dirty caps\n");
1590                         goto ack;
1591                 }
1592 
1593                 /* completed revocation? going down and there are no caps? */
1594                 if (revoking && (revoking & used) == 0) {
1595                         dout("completed revocation of %s\n",
1596                              ceph_cap_string(cap->implemented & ~cap->issued));
1597                         goto ack;
1598                 }
1599 
1600                 /* want more caps from mds? */
1601                 if (want & ~(cap->mds_wanted | cap->issued))
1602                         goto ack;
1603 
1604                 /* things we might delay */
1605                 if ((cap->issued & ~retain) == 0 &&
1606                     cap->mds_wanted == want)
1607                         continue;     /* nope, all good */
1608 
1609                 if (is_delayed)
1610                         goto ack;
1611 
1612                 /* delay? */
1613                 if ((ci->i_ceph_flags & CEPH_I_NODELAY) == 0 &&
1614                     time_before(jiffies, ci->i_hold_caps_max)) {
1615                         dout(" delaying issued %s -> %s, wanted %s -> %s\n",
1616                              ceph_cap_string(cap->issued),
1617                              ceph_cap_string(cap->issued & retain),
1618                              ceph_cap_string(cap->mds_wanted),
1619                              ceph_cap_string(want));
1620                         delayed++;
1621                         continue;
1622                 }
1623 
1624 ack:
1625                 if (ci->i_ceph_flags & CEPH_I_NOFLUSH) {
1626                         dout(" skipping %p I_NOFLUSH set\n", inode);
1627                         continue;
1628                 }
1629 
1630                 if (session && session != cap->session) {
1631                         dout("oops, wrong session %p mutex\n", session);
1632                         mutex_unlock(&session->s_mutex);
1633                         session = NULL;
1634                 }
1635                 if (!session) {
1636                         session = cap->session;
1637                         if (mutex_trylock(&session->s_mutex) == 0) {
1638                                 dout("inverting session/ino locks on %p\n",
1639                                      session);
1640                                 spin_unlock(&ci->i_ceph_lock);
1641                                 if (took_snap_rwsem) {
1642                                         up_read(&mdsc->snap_rwsem);
1643                                         took_snap_rwsem = 0;
1644                                 }
1645                                 mutex_lock(&session->s_mutex);
1646                                 goto retry;
1647                         }
1648                 }
1649                 /* take snap_rwsem after session mutex */
1650                 if (!took_snap_rwsem) {
1651                         if (down_read_trylock(&mdsc->snap_rwsem) == 0) {
1652                                 dout("inverting snap/in locks on %p\n",
1653                                      inode);
1654                                 spin_unlock(&ci->i_ceph_lock);
1655                                 down_read(&mdsc->snap_rwsem);
1656                                 took_snap_rwsem = 1;
1657                                 goto retry;
1658                         }
1659                         took_snap_rwsem = 1;
1660                 }
1661 
1662                 if (cap == ci->i_auth_cap && ci->i_dirty_caps)
1663                         flushing = __mark_caps_flushing(inode, session);
1664                 else
1665                         flushing = 0;
1666 
1667                 mds = cap->mds;  /* remember mds, so we don't repeat */
1668                 sent++;
1669 
1670                 /* __send_cap drops i_ceph_lock */
1671                 delayed += __send_cap(mdsc, cap, CEPH_CAP_OP_UPDATE, used, want,
1672                                       retain, flushing, NULL);
1673                 goto retry; /* retake i_ceph_lock and restart our cap scan. */
1674         }
1675 
1676         /*
1677          * Reschedule delayed caps release if we delayed anything,
1678          * otherwise cancel.
1679          */
1680         if (delayed && is_delayed)
1681                 force_requeue = 1;   /* __send_cap delayed release; requeue */
1682         if (!delayed && !is_delayed)
1683                 __cap_delay_cancel(mdsc, ci);
1684         else if (!is_delayed || force_requeue)
1685                 __cap_delay_requeue(mdsc, ci);
1686 
1687         spin_unlock(&ci->i_ceph_lock);
1688 
1689         if (queue_invalidate)
1690                 ceph_queue_invalidate(inode);
1691 
1692         if (session)
1693                 mutex_unlock(&session->s_mutex);
1694         if (took_snap_rwsem)
1695                 up_read(&mdsc->snap_rwsem);
1696 }
1697 
1698 /*
1699  * Try to flush dirty caps back to the auth mds.
1700  */
1701 static int try_flush_caps(struct inode *inode, struct ceph_mds_session *session,
1702                           unsigned *flush_tid)
1703 {
1704         struct ceph_mds_client *mdsc = ceph_sb_to_client(inode->i_sb)->mdsc;
1705         struct ceph_inode_info *ci = ceph_inode(inode);
1706         int unlock_session = session ? 0 : 1;
1707         int flushing = 0;
1708 
1709 retry:
1710         spin_lock(&ci->i_ceph_lock);
1711         if (ci->i_ceph_flags & CEPH_I_NOFLUSH) {
1712                 dout("try_flush_caps skipping %p I_NOFLUSH set\n", inode);
1713                 goto out;
1714         }
1715         if (ci->i_dirty_caps && ci->i_auth_cap) {
1716                 struct ceph_cap *cap = ci->i_auth_cap;
1717                 int used = __ceph_caps_used(ci);
1718                 int want = __ceph_caps_wanted(ci);
1719                 int delayed;
1720 
1721                 if (!session) {
1722                         spin_unlock(&ci->i_ceph_lock);
1723                         session = cap->session;
1724                         mutex_lock(&session->s_mutex);
1725                         goto retry;
1726                 }
1727                 BUG_ON(session != cap->session);
1728                 if (cap->session->s_state < CEPH_MDS_SESSION_OPEN)
1729                         goto out;
1730 
1731                 flushing = __mark_caps_flushing(inode, session);
1732 
1733                 /* __send_cap drops i_ceph_lock */
1734                 delayed = __send_cap(mdsc, cap, CEPH_CAP_OP_FLUSH, used, want,
1735                                      cap->issued | cap->implemented, flushing,
1736                                      flush_tid);
1737                 if (!delayed)
1738                         goto out_unlocked;
1739 
1740                 spin_lock(&ci->i_ceph_lock);
1741                 __cap_delay_requeue(mdsc, ci);
1742         }
1743 out:
1744         spin_unlock(&ci->i_ceph_lock);
1745 out_unlocked:
1746         if (session && unlock_session)
1747                 mutex_unlock(&session->s_mutex);
1748         return flushing;
1749 }
1750 
1751 /*
1752  * Return true if we've flushed caps through the given flush_tid.
1753  */
1754 static int caps_are_flushed(struct inode *inode, unsigned tid)
1755 {
1756         struct ceph_inode_info *ci = ceph_inode(inode);
1757         int i, ret = 1;
1758 
1759         spin_lock(&ci->i_ceph_lock);
1760         for (i = 0; i < CEPH_CAP_BITS; i++)
1761                 if ((ci->i_flushing_caps & (1 << i)) &&
1762                     ci->i_cap_flush_tid[i] <= tid) {
1763                         /* still flushing this bit */
1764                         ret = 0;
1765                         break;
1766                 }
1767         spin_unlock(&ci->i_ceph_lock);
1768         return ret;
1769 }
1770 
1771 /*
1772  * Wait on any unsafe replies for the given inode.  First wait on the
1773  * newest request, and make that the upper bound.  Then, if there are
1774  * more requests, keep waiting on the oldest as long as it is still older
1775  * than the original request.
1776  */
1777 static void sync_write_wait(struct inode *inode)
1778 {
1779         struct ceph_inode_info *ci = ceph_inode(inode);
1780         struct list_head *head = &ci->i_unsafe_writes;
1781         struct ceph_osd_request *req;
1782         u64 last_tid;
1783 
1784         spin_lock(&ci->i_unsafe_lock);
1785         if (list_empty(head))
1786                 goto out;
1787 
1788         /* set upper bound as _last_ entry in chain */
1789         req = list_entry(head->prev, struct ceph_osd_request,
1790                          r_unsafe_item);
1791         last_tid = req->r_tid;
1792 
1793         do {
1794                 ceph_osdc_get_request(req);
1795                 spin_unlock(&ci->i_unsafe_lock);
1796                 dout("sync_write_wait on tid %llu (until %llu)\n",
1797                      req->r_tid, last_tid);
1798                 wait_for_completion(&req->r_safe_completion);
1799                 spin_lock(&ci->i_unsafe_lock);
1800                 ceph_osdc_put_request(req);
1801 
1802                 /*
1803                  * from here on look at first entry in chain, since we
1804                  * only want to wait for anything older than last_tid
1805                  */
1806                 if (list_empty(head))
1807                         break;
1808                 req = list_entry(head->next, struct ceph_osd_request,
1809                                  r_unsafe_item);
1810         } while (req->r_tid < last_tid);
1811 out:
1812         spin_unlock(&ci->i_unsafe_lock);
1813 }
1814 
1815 int ceph_fsync(struct file *file, loff_t start, loff_t end, int datasync)
1816 {
1817         struct inode *inode = file->f_mapping->host;
1818         struct ceph_inode_info *ci = ceph_inode(inode);
1819         unsigned flush_tid;
1820         int ret;
1821         int dirty;
1822 
1823         dout("fsync %p%s\n", inode, datasync ? " datasync" : "");
1824         sync_write_wait(inode);
1825 
1826         ret = filemap_write_and_wait_range(inode->i_mapping, start, end);
1827         if (ret < 0)
1828                 return ret;
1829         mutex_lock(&inode->i_mutex);
1830 
1831         dirty = try_flush_caps(inode, NULL, &flush_tid);
1832         dout("fsync dirty caps are %s\n", ceph_cap_string(dirty));
1833 
1834         /*
1835          * only wait on non-file metadata writeback (the mds
1836          * can recover size and mtime, so we don't need to
1837          * wait for that)
1838          */
1839         if (!datasync && (dirty & ~CEPH_CAP_ANY_FILE_WR)) {
1840                 dout("fsync waiting for flush_tid %u\n", flush_tid);
1841                 ret = wait_event_interruptible(ci->i_cap_wq,
1842                                        caps_are_flushed(inode, flush_tid));
1843         }
1844 
1845         dout("fsync %p%s done\n", inode, datasync ? " datasync" : "");
1846         mutex_unlock(&inode->i_mutex);
1847         return ret;
1848 }
1849 
1850 /*
1851  * Flush any dirty caps back to the mds.  If we aren't asked to wait,
1852  * queue inode for flush but don't do so immediately, because we can
1853  * get by with fewer MDS messages if we wait for data writeback to
1854  * complete first.
1855  */
1856 int ceph_write_inode(struct inode *inode, struct writeback_control *wbc)
1857 {
1858         struct ceph_inode_info *ci = ceph_inode(inode);
1859         unsigned flush_tid;
1860         int err = 0;
1861         int dirty;
1862         int wait = wbc->sync_mode == WB_SYNC_ALL;
1863 
1864         dout("write_inode %p wait=%d\n", inode, wait);
1865         if (wait) {
1866                 dirty = try_flush_caps(inode, NULL, &flush_tid);
1867                 if (dirty)
1868                         err = wait_event_interruptible(ci->i_cap_wq,
1869                                        caps_are_flushed(inode, flush_tid));
1870         } else {
1871                 struct ceph_mds_client *mdsc =
1872                         ceph_sb_to_client(inode->i_sb)->mdsc;
1873 
1874                 spin_lock(&ci->i_ceph_lock);
1875                 if (__ceph_caps_dirty(ci))
1876                         __cap_delay_requeue_front(mdsc, ci);
1877                 spin_unlock(&ci->i_ceph_lock);
1878         }
1879         return err;
1880 }
1881 
1882 /*
1883  * After a recovering MDS goes active, we need to resend any caps
1884  * we were flushing.
1885  *
1886  * Caller holds session->s_mutex.
1887  */
1888 static void kick_flushing_capsnaps(struct ceph_mds_client *mdsc,
1889                                    struct ceph_mds_session *session)
1890 {
1891         struct ceph_cap_snap *capsnap;
1892 
1893         dout("kick_flushing_capsnaps mds%d\n", session->s_mds);
1894         list_for_each_entry(capsnap, &session->s_cap_snaps_flushing,
1895                             flushing_item) {
1896                 struct ceph_inode_info *ci = capsnap->ci;
1897                 struct inode *inode = &ci->vfs_inode;
1898                 struct ceph_cap *cap;
1899 
1900                 spin_lock(&ci->i_ceph_lock);
1901                 cap = ci->i_auth_cap;
1902                 if (cap && cap->session == session) {
1903                         dout("kick_flushing_caps %p cap %p capsnap %p\n", inode,
1904                              cap, capsnap);
1905                         __ceph_flush_snaps(ci, &session, 1);
1906                 } else {
1907                         pr_err("%p auth cap %p not mds%d ???\n", inode,
1908                                cap, session->s_mds);
1909                 }
1910                 spin_unlock(&ci->i_ceph_lock);
1911         }
1912 }
1913 
1914 void ceph_kick_flushing_caps(struct ceph_mds_client *mdsc,
1915                              struct ceph_mds_session *session)
1916 {
1917         struct ceph_inode_info *ci;
1918 
1919         kick_flushing_capsnaps(mdsc, session);
1920 
1921         dout("kick_flushing_caps mds%d\n", session->s_mds);
1922         list_for_each_entry(ci, &session->s_cap_flushing, i_flushing_item) {
1923                 struct inode *inode = &ci->vfs_inode;
1924                 struct ceph_cap *cap;
1925                 int delayed = 0;
1926 
1927                 spin_lock(&ci->i_ceph_lock);
1928                 cap = ci->i_auth_cap;
1929                 if (cap && cap->session == session) {
1930                         dout("kick_flushing_caps %p cap %p %s\n", inode,
1931                              cap, ceph_cap_string(ci->i_flushing_caps));
1932                         delayed = __send_cap(mdsc, cap, CEPH_CAP_OP_FLUSH,
1933                                              __ceph_caps_used(ci),
1934                                              __ceph_caps_wanted(ci),
1935                                              cap->issued | cap->implemented,
1936                                              ci->i_flushing_caps, NULL);
1937                         if (delayed) {
1938                                 spin_lock(&ci->i_ceph_lock);
1939                                 __cap_delay_requeue(mdsc, ci);
1940                                 spin_unlock(&ci->i_ceph_lock);
1941                         }
1942                 } else {
1943                         pr_err("%p auth cap %p not mds%d ???\n", inode,
1944                                cap, session->s_mds);
1945                         spin_unlock(&ci->i_ceph_lock);
1946                 }
1947         }
1948 }
1949 
1950 static void kick_flushing_inode_caps(struct ceph_mds_client *mdsc,
1951                                      struct ceph_mds_session *session,
1952                                      struct inode *inode)
1953 {
1954         struct ceph_inode_info *ci = ceph_inode(inode);
1955         struct ceph_cap *cap;
1956         int delayed = 0;
1957 
1958         spin_lock(&ci->i_ceph_lock);
1959         cap = ci->i_auth_cap;
1960         dout("kick_flushing_inode_caps %p flushing %s flush_seq %lld\n", inode,
1961              ceph_cap_string(ci->i_flushing_caps), ci->i_cap_flush_seq);
1962         __ceph_flush_snaps(ci, &session, 1);
1963         if (ci->i_flushing_caps) {
1964                 delayed = __send_cap(mdsc, cap, CEPH_CAP_OP_FLUSH,
1965                                      __ceph_caps_used(ci),
1966                                      __ceph_caps_wanted(ci),
1967                                      cap->issued | cap->implemented,
1968                                      ci->i_flushing_caps, NULL);
1969                 if (delayed) {
1970                         spin_lock(&ci->i_ceph_lock);
1971                         __cap_delay_requeue(mdsc, ci);
1972                         spin_unlock(&ci->i_ceph_lock);
1973                 }
1974         } else {
1975                 spin_unlock(&ci->i_ceph_lock);
1976         }
1977 }
1978 
1979 
1980 /*
1981  * Take references to capabilities we hold, so that we don't release
1982  * them to the MDS prematurely.
1983  *
1984  * Protected by i_ceph_lock.
1985  */
1986 static void __take_cap_refs(struct ceph_inode_info *ci, int got)
1987 {
1988         if (got & CEPH_CAP_PIN)
1989                 ci->i_pin_ref++;
1990         if (got & CEPH_CAP_FILE_RD)
1991                 ci->i_rd_ref++;
1992         if (got & CEPH_CAP_FILE_CACHE)
1993                 ci->i_rdcache_ref++;
1994         if (got & CEPH_CAP_FILE_WR)
1995                 ci->i_wr_ref++;
1996         if (got & CEPH_CAP_FILE_BUFFER) {
1997                 if (ci->i_wb_ref == 0)
1998                         ihold(&ci->vfs_inode);
1999                 ci->i_wb_ref++;
2000                 dout("__take_cap_refs %p wb %d -> %d (?)\n",
2001                      &ci->vfs_inode, ci->i_wb_ref-1, ci->i_wb_ref);
2002         }
2003 }
2004 
2005 /*
2006  * Try to grab cap references.  Specify those refs we @want, and the
2007  * minimal set we @need.  Also include the larger offset we are writing
2008  * to (when applicable), and check against max_size here as well.
2009  * Note that caller is responsible for ensuring max_size increases are
2010  * requested from the MDS.
2011  */
2012 static int try_get_cap_refs(struct ceph_inode_info *ci, int need, int want,
2013                             int *got, loff_t endoff, int *check_max, int *err)
2014 {
2015         struct inode *inode = &ci->vfs_inode;
2016         int ret = 0;
2017         int have, implemented;
2018         int file_wanted;
2019 
2020         dout("get_cap_refs %p need %s want %s\n", inode,
2021              ceph_cap_string(need), ceph_cap_string(want));
2022         spin_lock(&ci->i_ceph_lock);
2023 
2024         /* make sure file is actually open */
2025         file_wanted = __ceph_caps_file_wanted(ci);
2026         if ((file_wanted & need) == 0) {
2027                 dout("try_get_cap_refs need %s file_wanted %s, EBADF\n",
2028                      ceph_cap_string(need), ceph_cap_string(file_wanted));
2029                 *err = -EBADF;
2030                 ret = 1;
2031                 goto out;
2032         }
2033 
2034         if (need & CEPH_CAP_FILE_WR) {
2035                 if (endoff >= 0 && endoff > (loff_t)ci->i_max_size) {
2036                         dout("get_cap_refs %p endoff %llu > maxsize %llu\n",
2037                              inode, endoff, ci->i_max_size);
2038                         if (endoff > ci->i_wanted_max_size) {
2039                                 *check_max = 1;
2040                                 ret = 1;
2041                         }
2042                         goto out;
2043                 }
2044                 /*
2045                  * If a sync write is in progress, we must wait, so that we
2046                  * can get a final snapshot value for size+mtime.
2047                  */
2048                 if (__ceph_have_pending_cap_snap(ci)) {
2049                         dout("get_cap_refs %p cap_snap_pending\n", inode);
2050                         goto out;
2051                 }
2052         }
2053         have = __ceph_caps_issued(ci, &implemented);
2054 
2055         /*
2056          * disallow writes while a truncate is pending
2057          */
2058         if (ci->i_truncate_pending)
2059                 have &= ~CEPH_CAP_FILE_WR;
2060 
2061         if ((have & need) == need) {
2062                 /*
2063                  * Look at (implemented & ~have & not) so that we keep waiting
2064                  * on transition from wanted -> needed caps.  This is needed
2065                  * for WRBUFFER|WR -> WR to avoid a new WR sync write from
2066                  * going before a prior buffered writeback happens.
2067                  */
2068                 int not = want & ~(have & need);
2069                 int revoking = implemented & ~have;
2070                 dout("get_cap_refs %p have %s but not %s (revoking %s)\n",
2071                      inode, ceph_cap_string(have), ceph_cap_string(not),
2072                      ceph_cap_string(revoking));
2073                 if ((revoking & not) == 0) {
2074                         *got = need | (have & want);
2075                         __take_cap_refs(ci, *got);
2076                         ret = 1;
2077                 }
2078         } else {
2079                 dout("get_cap_refs %p have %s needed %s\n", inode,
2080                      ceph_cap_string(have), ceph_cap_string(need));
2081         }
2082 out:
2083         spin_unlock(&ci->i_ceph_lock);
2084         dout("get_cap_refs %p ret %d got %s\n", inode,
2085              ret, ceph_cap_string(*got));
2086         return ret;
2087 }
2088 
2089 /*
2090  * Check the offset we are writing up to against our current
2091  * max_size.  If necessary, tell the MDS we want to write to
2092  * a larger offset.
2093  */
2094 static void check_max_size(struct inode *inode, loff_t endoff)
2095 {
2096         struct ceph_inode_info *ci = ceph_inode(inode);
2097         int check = 0;
2098 
2099         /* do we need to explicitly request a larger max_size? */
2100         spin_lock(&ci->i_ceph_lock);
2101         if ((endoff >= ci->i_max_size ||
2102              endoff > (inode->i_size << 1)) &&
2103             endoff > ci->i_wanted_max_size) {
2104                 dout("write %p at large endoff %llu, req max_size\n",
2105                      inode, endoff);
2106                 ci->i_wanted_max_size = endoff;
2107                 check = 1;
2108         }
2109         spin_unlock(&ci->i_ceph_lock);
2110         if (check)
2111                 ceph_check_caps(ci, CHECK_CAPS_AUTHONLY, NULL);
2112 }
2113 
2114 /*
2115  * Wait for caps, and take cap references.  If we can't get a WR cap
2116  * due to a small max_size, make sure we check_max_size (and possibly
2117  * ask the mds) so we don't get hung up indefinitely.
2118  */
2119 int ceph_get_caps(struct ceph_inode_info *ci, int need, int want, int *got,
2120                   loff_t endoff)
2121 {
2122         int check_max, ret, err;
2123 
2124 retry:
2125         if (endoff > 0)
2126                 check_max_size(&ci->vfs_inode, endoff);
2127         check_max = 0;
2128         err = 0;
2129         ret = wait_event_interruptible(ci->i_cap_wq,
2130                                        try_get_cap_refs(ci, need, want,
2131                                                         got, endoff,
2132                                                         &check_max, &err));
2133         if (err)
2134                 ret = err;
2135         if (check_max)
2136                 goto retry;
2137         return ret;
2138 }
2139 
2140 /*
2141  * Take cap refs.  Caller must already know we hold at least one ref
2142  * on the caps in question or we don't know this is safe.
2143  */
2144 void ceph_get_cap_refs(struct ceph_inode_info *ci, int caps)
2145 {
2146         spin_lock(&ci->i_ceph_lock);
2147         __take_cap_refs(ci, caps);
2148         spin_unlock(&ci->i_ceph_lock);
2149 }
2150 
2151 /*
2152  * Release cap refs.
2153  *
2154  * If we released the last ref on any given cap, call ceph_check_caps
2155  * to release (or schedule a release).
2156  *
2157  * If we are releasing a WR cap (from a sync write), finalize any affected
2158  * cap_snap, and wake up any waiters.
2159  */
2160 void ceph_put_cap_refs(struct ceph_inode_info *ci, int had)
2161 {
2162         struct inode *inode = &ci->vfs_inode;
2163         int last = 0, put = 0, flushsnaps = 0, wake = 0;
2164         struct ceph_cap_snap *capsnap;
2165 
2166         spin_lock(&ci->i_ceph_lock);
2167         if (had & CEPH_CAP_PIN)
2168                 --ci->i_pin_ref;
2169         if (had & CEPH_CAP_FILE_RD)
2170                 if (--ci->i_rd_ref == 0)
2171                         last++;
2172         if (had & CEPH_CAP_FILE_CACHE)
2173                 if (--ci->i_rdcache_ref == 0)
2174                         last++;
2175         if (had & CEPH_CAP_FILE_BUFFER) {
2176                 if (--ci->i_wb_ref == 0) {
2177                         last++;
2178                         put++;
2179                 }
2180                 dout("put_cap_refs %p wb %d -> %d (?)\n",
2181                      inode, ci->i_wb_ref+1, ci->i_wb_ref);
2182         }
2183         if (had & CEPH_CAP_FILE_WR)
2184                 if (--ci->i_wr_ref == 0) {
2185                         last++;
2186                         if (!list_empty(&ci->i_cap_snaps)) {
2187                                 capsnap = list_first_entry(&ci->i_cap_snaps,
2188                                                      struct ceph_cap_snap,
2189                                                      ci_item);
2190                                 if (capsnap->writing) {
2191                                         capsnap->writing = 0;
2192                                         flushsnaps =
2193                                                 __ceph_finish_cap_snap(ci,
2194                                                                        capsnap);
2195                                         wake = 1;
2196                                 }
2197                         }
2198                 }
2199         spin_unlock(&ci->i_ceph_lock);
2200 
2201         dout("put_cap_refs %p had %s%s%s\n", inode, ceph_cap_string(had),
2202              last ? " last" : "", put ? " put" : "");
2203 
2204         if (last && !flushsnaps)
2205                 ceph_check_caps(ci, 0, NULL);
2206         else if (flushsnaps)
2207                 ceph_flush_snaps(ci);
2208         if (wake)
2209                 wake_up_all(&ci->i_cap_wq);
2210         if (put)
2211                 iput(inode);
2212 }
2213 
2214 /*
2215  * Release @nr WRBUFFER refs on dirty pages for the given @snapc snap
2216  * context.  Adjust per-snap dirty page accounting as appropriate.
2217  * Once all dirty data for a cap_snap is flushed, flush snapped file
2218  * metadata back to the MDS.  If we dropped the last ref, call
2219  * ceph_check_caps.
2220  */
2221 void ceph_put_wrbuffer_cap_refs(struct ceph_inode_info *ci, int nr,
2222                                 struct ceph_snap_context *snapc)
2223 {
2224         struct inode *inode = &ci->vfs_inode;
2225         int last = 0;
2226         int complete_capsnap = 0;
2227         int drop_capsnap = 0;
2228         int found = 0;
2229         struct ceph_cap_snap *capsnap = NULL;
2230 
2231         spin_lock(&ci->i_ceph_lock);
2232         ci->i_wrbuffer_ref -= nr;
2233         last = !ci->i_wrbuffer_ref;
2234 
2235         if (ci->i_head_snapc == snapc) {
2236                 ci->i_wrbuffer_ref_head -= nr;
2237                 if (ci->i_wrbuffer_ref_head == 0 &&
2238                     ci->i_dirty_caps == 0 && ci->i_flushing_caps == 0) {
2239                         BUG_ON(!ci->i_head_snapc);
2240                         ceph_put_snap_context(ci->i_head_snapc);
2241                         ci->i_head_snapc = NULL;
2242                 }
2243                 dout("put_wrbuffer_cap_refs on %p head %d/%d -> %d/%d %s\n",
2244                      inode,
2245                      ci->i_wrbuffer_ref+nr, ci->i_wrbuffer_ref_head+nr,
2246                      ci->i_wrbuffer_ref, ci->i_wrbuffer_ref_head,
2247                      last ? " LAST" : "");
2248         } else {
2249                 list_for_each_entry(capsnap, &ci->i_cap_snaps, ci_item) {
2250                         if (capsnap->context == snapc) {
2251                                 found = 1;
2252                                 break;
2253                         }
2254                 }
2255                 BUG_ON(!found);
2256                 capsnap->dirty_pages -= nr;
2257                 if (capsnap->dirty_pages == 0) {
2258                         complete_capsnap = 1;
2259                         if (capsnap->dirty == 0)
2260                                 /* cap writeback completed before we created
2261                                  * the cap_snap; no FLUSHSNAP is needed */
2262                                 drop_capsnap = 1;
2263                 }
2264                 dout("put_wrbuffer_cap_refs on %p cap_snap %p "
2265                      " snap %lld %d/%d -> %d/%d %s%s%s\n",
2266                      inode, capsnap, capsnap->context->seq,
2267                      ci->i_wrbuffer_ref+nr, capsnap->dirty_pages + nr,
2268                      ci->i_wrbuffer_ref, capsnap->dirty_pages,
2269                      last ? " (wrbuffer last)" : "",
2270                      complete_capsnap ? " (complete capsnap)" : "",
2271                      drop_capsnap ? " (drop capsnap)" : "");
2272                 if (drop_capsnap) {
2273                         ceph_put_snap_context(capsnap->context);
2274                         list_del(&capsnap->ci_item);
2275                         list_del(&capsnap->flushing_item);
2276                         ceph_put_cap_snap(capsnap);
2277                 }
2278         }
2279 
2280         spin_unlock(&ci->i_ceph_lock);
2281 
2282         if (last) {
2283                 ceph_check_caps(ci, CHECK_CAPS_AUTHONLY, NULL);
2284                 iput(inode);
2285         } else if (complete_capsnap) {
2286                 ceph_flush_snaps(ci);
2287                 wake_up_all(&ci->i_cap_wq);
2288         }
2289         if (drop_capsnap)
2290                 iput(inode);
2291 }
2292 
2293 /*
2294  * Handle a cap GRANT message from the MDS.  (Note that a GRANT may
2295  * actually be a revocation if it specifies a smaller cap set.)
2296  *
2297  * caller holds s_mutex and i_ceph_lock, we drop both.
2298  *
2299  * return value:
2300  *  0 - ok
2301  *  1 - check_caps on auth cap only (writeback)
2302  *  2 - check_caps (ack revoke)
2303  */
2304 static void handle_cap_grant(struct inode *inode, struct ceph_mds_caps *grant,
2305                              struct ceph_mds_session *session,
2306                              struct ceph_cap *cap,
2307                              struct ceph_buffer *xattr_buf)
2308                 __releases(ci->i_ceph_lock)
2309 {
2310         struct ceph_inode_info *ci = ceph_inode(inode);
2311         int mds = session->s_mds;
2312         int seq = le32_to_cpu(grant->seq);
2313         int newcaps = le32_to_cpu(grant->caps);
2314         int issued, implemented, used, wanted, dirty;
2315         u64 size = le64_to_cpu(grant->size);
2316         u64 max_size = le64_to_cpu(grant->max_size);
2317         struct timespec mtime, atime, ctime;
2318         int check_caps = 0;
2319         int wake = 0;
2320         int writeback = 0;
2321         int revoked_rdcache = 0;
2322         int queue_invalidate = 0;
2323 
2324         dout("handle_cap_grant inode %p cap %p mds%d seq %d %s\n",
2325              inode, cap, mds, seq, ceph_cap_string(newcaps));
2326         dout(" size %llu max_size %llu, i_size %llu\n", size, max_size,
2327                 inode->i_size);
2328 
2329         /*
2330          * If CACHE is being revoked, and we have no dirty buffers,
2331          * try to invalidate (once).  (If there are dirty buffers, we
2332          * will invalidate _after_ writeback.)
2333          */
2334         if (((cap->issued & ~newcaps) & CEPH_CAP_FILE_CACHE) &&
2335             (newcaps & CEPH_CAP_FILE_LAZYIO) == 0 &&
2336             !ci->i_wrbuffer_ref) {
2337                 if (try_nonblocking_invalidate(inode) == 0) {
2338                         revoked_rdcache = 1;
2339                 } else {
2340                         /* there were locked pages.. invalidate later
2341                            in a separate thread. */
2342                         if (ci->i_rdcache_revoking != ci->i_rdcache_gen) {
2343                                 queue_invalidate = 1;
2344                                 ci->i_rdcache_revoking = ci->i_rdcache_gen;
2345                         }
2346                 }
2347         }
2348 
2349         /* side effects now are allowed */
2350 
2351         issued = __ceph_caps_issued(ci, &implemented);
2352         issued |= implemented | __ceph_caps_dirty(ci);
2353 
2354         cap->cap_gen = session->s_cap_gen;
2355 
2356         __check_cap_issue(ci, cap, newcaps);
2357 
2358         if ((issued & CEPH_CAP_AUTH_EXCL) == 0) {
2359                 inode->i_mode = le32_to_cpu(grant->mode);
2360                 inode->i_uid = le32_to_cpu(grant->uid);
2361                 inode->i_gid = le32_to_cpu(grant->gid);
2362                 dout("%p mode 0%o uid.gid %d.%d\n", inode, inode->i_mode,
2363                      inode->i_uid, inode->i_gid);
2364         }
2365 
2366         if ((issued & CEPH_CAP_LINK_EXCL) == 0)
2367                 set_nlink(inode, le32_to_cpu(grant->nlink));
2368 
2369         if ((issued & CEPH_CAP_XATTR_EXCL) == 0 && grant->xattr_len) {
2370                 int len = le32_to_cpu(grant->xattr_len);
2371                 u64 version = le64_to_cpu(grant->xattr_version);
2372 
2373                 if (version > ci->i_xattrs.version) {
2374                         dout(" got new xattrs v%llu on %p len %d\n",
2375                              version, inode, len);
2376                         if (ci->i_xattrs.blob)
2377                                 ceph_buffer_put(ci->i_xattrs.blob);
2378                         ci->i_xattrs.blob = ceph_buffer_get(xattr_buf);
2379                         ci->i_xattrs.version = version;
2380                 }
2381         }
2382 
2383         /* size/ctime/mtime/atime? */
2384         ceph_fill_file_size(inode, issued,
2385                             le32_to_cpu(grant->truncate_seq),
2386                             le64_to_cpu(grant->truncate_size), size);
2387         ceph_decode_timespec(&mtime, &grant->mtime);
2388         ceph_decode_timespec(&atime, &grant->atime);
2389         ceph_decode_timespec(&ctime, &grant->ctime);
2390         ceph_fill_file_time(inode, issued,
2391                             le32_to_cpu(grant->time_warp_seq), &ctime, &mtime,
2392                             &atime);
2393 
2394         /* max size increase? */
2395         if (ci->i_auth_cap == cap && max_size != ci->i_max_size) {
2396                 dout("max_size %lld -> %llu\n", ci->i_max_size, max_size);
2397                 ci->i_max_size = max_size;
2398                 if (max_size >= ci->i_wanted_max_size) {
2399                         ci->i_wanted_max_size = 0;  /* reset */
2400                         ci->i_requested_max_size = 0;
2401                 }
2402                 wake = 1;
2403         }
2404 
2405         /* check cap bits */
2406         wanted = __ceph_caps_wanted(ci);
2407         used = __ceph_caps_used(ci);
2408         dirty = __ceph_caps_dirty(ci);
2409         dout(" my wanted = %s, used = %s, dirty %s\n",
2410              ceph_cap_string(wanted),
2411              ceph_cap_string(used),
2412              ceph_cap_string(dirty));
2413         if (wanted != le32_to_cpu(grant->wanted)) {
2414                 dout("mds wanted %s -> %s\n",
2415                      ceph_cap_string(le32_to_cpu(grant->wanted)),
2416                      ceph_cap_string(wanted));
2417                 grant->wanted = cpu_to_le32(wanted);
2418         }
2419 
2420         cap->seq = seq;
2421 
2422         /* file layout may have changed */
2423         ci->i_layout = grant->layout;
2424 
2425         /* revocation, grant, or no-op? */
2426         if (cap->issued & ~newcaps) {
2427                 int revoking = cap->issued & ~newcaps;
2428 
2429                 dout("revocation: %s -> %s (revoking %s)\n",
2430                      ceph_cap_string(cap->issued),
2431                      ceph_cap_string(newcaps),
2432                      ceph_cap_string(revoking));
2433                 if (revoking & used & CEPH_CAP_FILE_BUFFER)
2434                         writeback = 1;  /* initiate writeback; will delay ack */
2435                 else if (revoking == CEPH_CAP_FILE_CACHE &&
2436                          (newcaps & CEPH_CAP_FILE_LAZYIO) == 0 &&
2437                          queue_invalidate)
2438                         ; /* do nothing yet, invalidation will be queued */
2439                 else if (cap == ci->i_auth_cap)
2440                         check_caps = 1; /* check auth cap only */
2441                 else
2442                         check_caps = 2; /* check all caps */
2443                 cap->issued = newcaps;
2444                 cap->implemented |= newcaps;
2445         } else if (cap->issued == newcaps) {
2446                 dout("caps unchanged: %s -> %s\n",
2447                      ceph_cap_string(cap->issued), ceph_cap_string(newcaps));
2448         } else {
2449                 dout("grant: %s -> %s\n", ceph_cap_string(cap->issued),
2450                      ceph_cap_string(newcaps));
2451                 cap->issued = newcaps;
2452                 cap->implemented |= newcaps; /* add bits only, to
2453                                               * avoid stepping on a
2454                                               * pending revocation */
2455                 wake = 1;
2456         }
2457         BUG_ON(cap->issued & ~cap->implemented);
2458 
2459         spin_unlock(&ci->i_ceph_lock);
2460         if (writeback)
2461                 /*
2462                  * queue inode for writeback: we can't actually call
2463                  * filemap_write_and_wait, etc. from message handler
2464                  * context.
2465                  */
2466                 ceph_queue_writeback(inode);
2467         if (queue_invalidate)
2468                 ceph_queue_invalidate(inode);
2469         if (wake)
2470                 wake_up_all(&ci->i_cap_wq);
2471 
2472         if (check_caps == 1)
2473                 ceph_check_caps(ci, CHECK_CAPS_NODELAY|CHECK_CAPS_AUTHONLY,
2474                                 session);
2475         else if (check_caps == 2)
2476                 ceph_check_caps(ci, CHECK_CAPS_NODELAY, session);
2477         else
2478                 mutex_unlock(&session->s_mutex);
2479 }
2480 
2481 /*
2482  * Handle FLUSH_ACK from MDS, indicating that metadata we sent to the
2483  * MDS has been safely committed.
2484  */
2485 static void handle_cap_flush_ack(struct inode *inode, u64 flush_tid,
2486                                  struct ceph_mds_caps *m,
2487                                  struct ceph_mds_session *session,
2488                                  struct ceph_cap *cap)
2489         __releases(ci->i_ceph_lock)
2490 {
2491         struct ceph_inode_info *ci = ceph_inode(inode);
2492         struct ceph_mds_client *mdsc = ceph_sb_to_client(inode->i_sb)->mdsc;
2493         unsigned seq = le32_to_cpu(m->seq);
2494         int dirty = le32_to_cpu(m->dirty);
2495         int cleaned = 0;
2496         int drop = 0;
2497         int i;
2498 
2499         for (i = 0; i < CEPH_CAP_BITS; i++)
2500                 if ((dirty & (1 << i)) &&
2501                     flush_tid == ci->i_cap_flush_tid[i])
2502                         cleaned |= 1 << i;
2503 
2504         dout("handle_cap_flush_ack inode %p mds%d seq %d on %s cleaned %s,"
2505              " flushing %s -> %s\n",
2506              inode, session->s_mds, seq, ceph_cap_string(dirty),
2507              ceph_cap_string(cleaned), ceph_cap_string(ci->i_flushing_caps),
2508              ceph_cap_string(ci->i_flushing_caps & ~cleaned));
2509 
2510         if (ci->i_flushing_caps == (ci->i_flushing_caps & ~cleaned))
2511                 goto out;
2512 
2513         ci->i_flushing_caps &= ~cleaned;
2514 
2515         spin_lock(&mdsc->cap_dirty_lock);
2516         if (ci->i_flushing_caps == 0) {
2517                 list_del_init(&ci->i_flushing_item);
2518                 if (!list_empty(&session->s_cap_flushing))
2519                         dout(" mds%d still flushing cap on %p\n",
2520                              session->s_mds,
2521                              &list_entry(session->s_cap_flushing.next,
2522                                          struct ceph_inode_info,
2523                                          i_flushing_item)->vfs_inode);
2524                 mdsc->num_cap_flushing--;
2525                 wake_up_all(&mdsc->cap_flushing_wq);
2526                 dout(" inode %p now !flushing\n", inode);
2527 
2528                 if (ci->i_dirty_caps == 0) {
2529                         dout(" inode %p now clean\n", inode);
2530                         BUG_ON(!list_empty(&ci->i_dirty_item));
2531                         drop = 1;
2532                         if (ci->i_wrbuffer_ref_head == 0) {
2533                                 BUG_ON(!ci->i_head_snapc);
2534                                 ceph_put_snap_context(ci->i_head_snapc);
2535                                 ci->i_head_snapc = NULL;
2536                         }
2537                 } else {
2538                         BUG_ON(list_empty(&ci->i_dirty_item));
2539                 }
2540         }
2541         spin_unlock(&mdsc->cap_dirty_lock);
2542         wake_up_all(&ci->i_cap_wq);
2543 
2544 out:
2545         spin_unlock(&ci->i_ceph_lock);
2546         if (drop)
2547                 iput(inode);
2548 }
2549 
2550 /*
2551  * Handle FLUSHSNAP_ACK.  MDS has flushed snap data to disk and we can
2552  * throw away our cap_snap.
2553  *
2554  * Caller hold s_mutex.
2555  */
2556 static void handle_cap_flushsnap_ack(struct inode *inode, u64 flush_tid,
2557                                      struct ceph_mds_caps *m,
2558                                      struct ceph_mds_session *session)
2559 {
2560         struct ceph_inode_info *ci = ceph_inode(inode);
2561         u64 follows = le64_to_cpu(m->snap_follows);
2562         struct ceph_cap_snap *capsnap;
2563         int drop = 0;
2564 
2565         dout("handle_cap_flushsnap_ack inode %p ci %p mds%d follows %lld\n",
2566              inode, ci, session->s_mds, follows);
2567 
2568         spin_lock(&ci->i_ceph_lock);
2569         list_for_each_entry(capsnap, &ci->i_cap_snaps, ci_item) {
2570                 if (capsnap->follows == follows) {
2571                         if (capsnap->flush_tid != flush_tid) {
2572                                 dout(" cap_snap %p follows %lld tid %lld !="
2573                                      " %lld\n", capsnap, follows,
2574                                      flush_tid, capsnap->flush_tid);
2575                                 break;
2576                         }
2577                         WARN_ON(capsnap->dirty_pages || capsnap->writing);
2578                         dout(" removing %p cap_snap %p follows %lld\n",
2579                              inode, capsnap, follows);
2580                         ceph_put_snap_context(capsnap->context);
2581                         list_del(&capsnap->ci_item);
2582                         list_del(&capsnap->flushing_item);
2583                         ceph_put_cap_snap(capsnap);
2584                         drop = 1;
2585                         break;
2586                 } else {
2587                         dout(" skipping cap_snap %p follows %lld\n",
2588                              capsnap, capsnap->follows);
2589                 }
2590         }
2591         spin_unlock(&ci->i_ceph_lock);
2592         if (drop)
2593                 iput(inode);
2594 }
2595 
2596 /*
2597  * Handle TRUNC from MDS, indicating file truncation.
2598  *
2599  * caller hold s_mutex.
2600  */
2601 static void handle_cap_trunc(struct inode *inode,
2602                              struct ceph_mds_caps *trunc,
2603                              struct ceph_mds_session *session)
2604         __releases(ci->i_ceph_lock)
2605 {
2606         struct ceph_inode_info *ci = ceph_inode(inode);
2607         int mds = session->s_mds;
2608         int seq = le32_to_cpu(trunc->seq);
2609         u32 truncate_seq = le32_to_cpu(trunc->truncate_seq);
2610         u64 truncate_size = le64_to_cpu(trunc->truncate_size);
2611         u64 size = le64_to_cpu(trunc->size);
2612         int implemented = 0;
2613         int dirty = __ceph_caps_dirty(ci);
2614         int issued = __ceph_caps_issued(ceph_inode(inode), &implemented);
2615         int queue_trunc = 0;
2616 
2617         issued |= implemented | dirty;
2618 
2619         dout("handle_cap_trunc inode %p mds%d seq %d to %lld seq %d\n",
2620              inode, mds, seq, truncate_size, truncate_seq);
2621         queue_trunc = ceph_fill_file_size(inode, issued,
2622                                           truncate_seq, truncate_size, size);
2623         spin_unlock(&ci->i_ceph_lock);
2624 
2625         if (queue_trunc)
2626                 ceph_queue_vmtruncate(inode);
2627 }
2628 
2629 /*
2630  * Handle EXPORT from MDS.  Cap is being migrated _from_ this mds to a
2631  * different one.  If we are the most recent migration we've seen (as
2632  * indicated by mseq), make note of the migrating cap bits for the
2633  * duration (until we see the corresponding IMPORT).
2634  *
2635  * caller holds s_mutex
2636  */
2637 static void handle_cap_export(struct inode *inode, struct ceph_mds_caps *ex,
2638                               struct ceph_mds_session *session,
2639                               int *open_target_sessions)
2640 {
2641         struct ceph_mds_client *mdsc = ceph_inode_to_client(inode)->mdsc;
2642         struct ceph_inode_info *ci = ceph_inode(inode);
2643         int mds = session->s_mds;
2644         unsigned mseq = le32_to_cpu(ex->migrate_seq);
2645         struct ceph_cap *cap = NULL, *t;
2646         struct rb_node *p;
2647         int remember = 1;
2648 
2649         dout("handle_cap_export inode %p ci %p mds%d mseq %d\n",
2650              inode, ci, mds, mseq);
2651 
2652         spin_lock(&ci->i_ceph_lock);
2653 
2654         /* make sure we haven't seen a higher mseq */
2655         for (p = rb_first(&ci->i_caps); p; p = rb_next(p)) {
2656                 t = rb_entry(p, struct ceph_cap, ci_node);
2657                 if (ceph_seq_cmp(t->mseq, mseq) > 0) {
2658                         dout(" higher mseq on cap from mds%d\n",
2659                              t->session->s_mds);
2660                         remember = 0;
2661                 }
2662                 if (t->session->s_mds == mds)
2663                         cap = t;
2664         }
2665 
2666         if (cap) {
2667                 if (remember) {
2668                         /* make note */
2669                         ci->i_cap_exporting_mds = mds;
2670                         ci->i_cap_exporting_mseq = mseq;
2671                         ci->i_cap_exporting_issued = cap->issued;
2672 
2673                         /*
2674                          * make sure we have open sessions with all possible
2675                          * export targets, so that we get the matching IMPORT
2676                          */
2677                         *open_target_sessions = 1;
2678 
2679                         /*
2680                          * we can't flush dirty caps that we've seen the
2681                          * EXPORT but no IMPORT for
2682                          */
2683                         spin_lock(&mdsc->cap_dirty_lock);
2684                         if (!list_empty(&ci->i_dirty_item)) {
2685                                 dout(" moving %p to cap_dirty_migrating\n",
2686                                      inode);
2687                                 list_move(&ci->i_dirty_item,
2688                                           &mdsc->cap_dirty_migrating);
2689                         }
2690                         spin_unlock(&mdsc->cap_dirty_lock);
2691                 }
2692                 __ceph_remove_cap(cap);
2693         }
2694         /* else, we already released it */
2695 
2696         spin_unlock(&ci->i_ceph_lock);
2697 }
2698 
2699 /*
2700  * Handle cap IMPORT.  If there are temp bits from an older EXPORT,
2701  * clean them up.
2702  *
2703  * caller holds s_mutex.
2704  */
2705 static void handle_cap_import(struct ceph_mds_client *mdsc,
2706                               struct inode *inode, struct ceph_mds_caps *im,
2707                               struct ceph_mds_session *session,
2708                               void *snaptrace, int snaptrace_len)
2709 {
2710         struct ceph_inode_info *ci = ceph_inode(inode);
2711         int mds = session->s_mds;
2712         unsigned issued = le32_to_cpu(im->caps);
2713         unsigned wanted = le32_to_cpu(im->wanted);
2714         unsigned seq = le32_to_cpu(im->seq);
2715         unsigned mseq = le32_to_cpu(im->migrate_seq);
2716         u64 realmino = le64_to_cpu(im->realm);
2717         u64 cap_id = le64_to_cpu(im->cap_id);
2718 
2719         if (ci->i_cap_exporting_mds >= 0 &&
2720             ceph_seq_cmp(ci->i_cap_exporting_mseq, mseq) < 0) {
2721                 dout("handle_cap_import inode %p ci %p mds%d mseq %d"
2722                      " - cleared exporting from mds%d\n",
2723                      inode, ci, mds, mseq,
2724                      ci->i_cap_exporting_mds);
2725                 ci->i_cap_exporting_issued = 0;
2726                 ci->i_cap_exporting_mseq = 0;
2727                 ci->i_cap_exporting_mds = -1;
2728 
2729                 spin_lock(&mdsc->cap_dirty_lock);
2730                 if (!list_empty(&ci->i_dirty_item)) {
2731                         dout(" moving %p back to cap_dirty\n", inode);
2732                         list_move(&ci->i_dirty_item, &mdsc->cap_dirty);
2733                 }
2734                 spin_unlock(&mdsc->cap_dirty_lock);
2735         } else {
2736                 dout("handle_cap_import inode %p ci %p mds%d mseq %d\n",
2737                      inode, ci, mds, mseq);
2738         }
2739 
2740         down_write(&mdsc->snap_rwsem);
2741         ceph_update_snap_trace(mdsc, snaptrace, snaptrace+snaptrace_len,
2742                                false);
2743         downgrade_write(&mdsc->snap_rwsem);
2744         ceph_add_cap(inode, session, cap_id, -1,
2745                      issued, wanted, seq, mseq, realmino, CEPH_CAP_FLAG_AUTH,
2746                      NULL /* no caps context */);
2747         kick_flushing_inode_caps(mdsc, session, inode);
2748         up_read(&mdsc->snap_rwsem);
2749 
2750         /* make sure we re-request max_size, if necessary */
2751         spin_lock(&ci->i_ceph_lock);
2752         ci->i_wanted_max_size = 0;  /* reset */
2753         ci->i_requested_max_size = 0;
2754         spin_unlock(&ci->i_ceph_lock);
2755 }
2756 
2757 /*
2758  * Handle a caps message from the MDS.
2759  *
2760  * Identify the appropriate session, inode, and call the right handler
2761  * based on the cap op.
2762  */
2763 void ceph_handle_caps(struct ceph_mds_session *session,
2764                       struct ceph_msg *msg)
2765 {
2766         struct ceph_mds_client *mdsc = session->s_mdsc;
2767         struct super_block *sb = mdsc->fsc->sb;
2768         struct inode *inode;
2769         struct ceph_inode_info *ci;
2770         struct ceph_cap *cap;
2771         struct ceph_mds_caps *h;
2772         int mds = session->s_mds;
2773         int op;
2774         u32 seq, mseq;
2775         struct ceph_vino vino;
2776         u64 cap_id;
2777         u64 size, max_size;
2778         u64 tid;
2779         void *snaptrace;
2780         size_t snaptrace_len;
2781         void *flock;
2782         u32 flock_len;
2783         int open_target_sessions = 0;
2784 
2785         dout("handle_caps from mds%d\n", mds);
2786 
2787         /* decode */
2788         tid = le64_to_cpu(msg->hdr.tid);
2789         if (msg->front.iov_len < sizeof(*h))
2790                 goto bad;
2791         h = msg->front.iov_base;
2792         op = le32_to_cpu(h->op);
2793         vino.ino = le64_to_cpu(h->ino);
2794         vino.snap = CEPH_NOSNAP;
2795         cap_id = le64_to_cpu(h->cap_id);
2796         seq = le32_to_cpu(h->seq);
2797         mseq = le32_to_cpu(h->migrate_seq);
2798         size = le64_to_cpu(h->size);
2799         max_size = le64_to_cpu(h->max_size);
2800 
2801         snaptrace = h + 1;
2802         snaptrace_len = le32_to_cpu(h->snap_trace_len);
2803 
2804         if (le16_to_cpu(msg->hdr.version) >= 2) {
2805                 void *p, *end;
2806 
2807                 p = snaptrace + snaptrace_len;
2808                 end = msg->front.iov_base + msg->front.iov_len;
2809                 ceph_decode_32_safe(&p, end, flock_len, bad);
2810                 flock = p;
2811         } else {
2812                 flock = NULL;
2813                 flock_len = 0;
2814         }
2815 
2816         mutex_lock(&session->s_mutex);
2817         session->s_seq++;
2818         dout(" mds%d seq %lld cap seq %u\n", session->s_mds, session->s_seq,
2819              (unsigned)seq);
2820 
2821         /* lookup ino */
2822         inode = ceph_find_inode(sb, vino);
2823         ci = ceph_inode(inode);
2824         dout(" op %s ino %llx.%llx inode %p\n", ceph_cap_op_name(op), vino.ino,
2825              vino.snap, inode);
2826         if (!inode) {
2827                 dout(" i don't have ino %llx\n", vino.ino);
2828 
2829                 if (op == CEPH_CAP_OP_IMPORT)
2830                         __queue_cap_release(session, vino.ino, cap_id,
2831                                             mseq, seq);
2832                 goto flush_cap_releases;
2833         }
2834 
2835         /* these will work even if we don't have a cap yet */
2836         switch (op) {
2837         case CEPH_CAP_OP_FLUSHSNAP_ACK:
2838                 handle_cap_flushsnap_ack(inode, tid, h, session);
2839                 goto done;
2840 
2841         case CEPH_CAP_OP_EXPORT:
2842                 handle_cap_export(inode, h, session, &open_target_sessions);
2843                 goto done;
2844 
2845         case CEPH_CAP_OP_IMPORT:
2846                 handle_cap_import(mdsc, inode, h, session,
2847                                   snaptrace, snaptrace_len);
2848         }
2849 
2850         /* the rest require a cap */
2851         spin_lock(&ci->i_ceph_lock);
2852         cap = __get_cap_for_mds(ceph_inode(inode), mds);
2853         if (!cap) {
2854                 dout(" no cap on %p ino %llx.%llx from mds%d\n",
2855                      inode, ceph_ino(inode), ceph_snap(inode), mds);
2856                 spin_unlock(&ci->i_ceph_lock);
2857                 goto flush_cap_releases;
2858         }
2859 
2860         /* note that each of these drops i_ceph_lock for us */
2861         switch (op) {
2862         case CEPH_CAP_OP_REVOKE:
2863         case CEPH_CAP_OP_GRANT:
2864         case CEPH_CAP_OP_IMPORT:
2865                 handle_cap_grant(inode, h, session, cap, msg->middle);
2866                 goto done_unlocked;
2867 
2868         case CEPH_CAP_OP_FLUSH_ACK:
2869                 handle_cap_flush_ack(inode, tid, h, session, cap);
2870                 break;
2871 
2872         case CEPH_CAP_OP_TRUNC:
2873                 handle_cap_trunc(inode, h, session);
2874                 break;
2875 
2876         default:
2877                 spin_unlock(&ci->i_ceph_lock);
2878                 pr_err("ceph_handle_caps: unknown cap op %d %s\n", op,
2879                        ceph_cap_op_name(op));
2880         }
2881 
2882         goto done;
2883 
2884 flush_cap_releases:
2885         /*
2886          * send any full release message to try to move things
2887          * along for the mds (who clearly thinks we still have this
2888          * cap).
2889          */
2890         ceph_add_cap_releases(mdsc, session);
2891         ceph_send_cap_releases(mdsc, session);
2892 
2893 done:
2894         mutex_unlock(&session->s_mutex);
2895 done_unlocked:
2896         if (inode)
2897                 iput(inode);
2898         if (open_target_sessions)
2899                 ceph_mdsc_open_export_target_sessions(mdsc, session);
2900         return;
2901 
2902 bad:
2903         pr_err("ceph_handle_caps: corrupt message\n");
2904         ceph_msg_dump(msg);
2905         return;
2906 }
2907 
2908 /*
2909  * Delayed work handler to process end of delayed cap release LRU list.
2910  */
2911 void ceph_check_delayed_caps(struct ceph_mds_client *mdsc)
2912 {
2913         struct ceph_inode_info *ci;
2914         int flags = CHECK_CAPS_NODELAY;
2915 
2916         dout("check_delayed_caps\n");
2917         while (1) {
2918                 spin_lock(&mdsc->cap_delay_lock);
2919                 if (list_empty(&mdsc->cap_delay_list))
2920                         break;
2921                 ci = list_first_entry(&mdsc->cap_delay_list,
2922                                       struct ceph_inode_info,
2923                                       i_cap_delay_list);
2924                 if ((ci->i_ceph_flags & CEPH_I_FLUSH) == 0 &&
2925                     time_before(jiffies, ci->i_hold_caps_max))
2926                         break;
2927                 list_del_init(&ci->i_cap_delay_list);
2928                 spin_unlock(&mdsc->cap_delay_lock);
2929                 dout("check_delayed_caps on %p\n", &ci->vfs_inode);
2930                 ceph_check_caps(ci, flags, NULL);
2931         }
2932         spin_unlock(&mdsc->cap_delay_lock);
2933 }
2934 
2935 /*
2936  * Flush all dirty caps to the mds
2937  */
2938 void ceph_flush_dirty_caps(struct ceph_mds_client *mdsc)
2939 {
2940         struct ceph_inode_info *ci;
2941         struct inode *inode;
2942 
2943         dout("flush_dirty_caps\n");
2944         spin_lock(&mdsc->cap_dirty_lock);
2945         while (!list_empty(&mdsc->cap_dirty)) {
2946                 ci = list_first_entry(&mdsc->cap_dirty, struct ceph_inode_info,
2947                                       i_dirty_item);
2948                 inode = &ci->vfs_inode;
2949                 ihold(inode);
2950                 dout("flush_dirty_caps %p\n", inode);
2951                 spin_unlock(&mdsc->cap_dirty_lock);
2952                 ceph_check_caps(ci, CHECK_CAPS_NODELAY|CHECK_CAPS_FLUSH, NULL);
2953                 iput(inode);
2954                 spin_lock(&mdsc->cap_dirty_lock);
2955         }
2956         spin_unlock(&mdsc->cap_dirty_lock);
2957         dout("flush_dirty_caps done\n");
2958 }
2959 
2960 /*
2961  * Drop open file reference.  If we were the last open file,
2962  * we may need to release capabilities to the MDS (or schedule
2963  * their delayed release).
2964  */
2965 void ceph_put_fmode(struct ceph_inode_info *ci, int fmode)
2966 {
2967         struct inode *inode = &ci->vfs_inode;
2968         int last = 0;
2969 
2970         spin_lock(&ci->i_ceph_lock);
2971         dout("put_fmode %p fmode %d %d -> %d\n", inode, fmode,
2972              ci->i_nr_by_mode[fmode], ci->i_nr_by_mode[fmode]-1);
2973         BUG_ON(ci->i_nr_by_mode[fmode] == 0);
2974         if (--ci->i_nr_by_mode[fmode] == 0)
2975                 last++;
2976         spin_unlock(&ci->i_ceph_lock);
2977 
2978         if (last && ci->i_vino.snap == CEPH_NOSNAP)
2979                 ceph_check_caps(ci, 0, NULL);
2980 }
2981 
2982 /*
2983  * Helpers for embedding cap and dentry lease releases into mds
2984  * requests.
2985  *
2986  * @force is used by dentry_release (below) to force inclusion of a
2987  * record for the directory inode, even when there aren't any caps to
2988  * drop.
2989  */
2990 int ceph_encode_inode_release(void **p, struct inode *inode,
2991                               int mds, int drop, int unless, int force)
2992 {
2993         struct ceph_inode_info *ci = ceph_inode(inode);
2994         struct ceph_cap *cap;
2995         struct ceph_mds_request_release *rel = *p;
2996         int used, dirty;
2997         int ret = 0;
2998 
2999         spin_lock(&ci->i_ceph_lock);
3000         used = __ceph_caps_used(ci);
3001         dirty = __ceph_caps_dirty(ci);
3002 
3003         dout("encode_inode_release %p mds%d used|dirty %s drop %s unless %s\n",
3004              inode, mds, ceph_cap_string(used|dirty), ceph_cap_string(drop),
3005              ceph_cap_string(unless));
3006 
3007         /* only drop unused, clean caps */
3008         drop &= ~(used | dirty);
3009 
3010         cap = __get_cap_for_mds(ci, mds);
3011         if (cap && __cap_is_valid(cap)) {
3012                 if (force ||
3013                     ((cap->issued & drop) &&
3014                      (cap->issued & unless) == 0)) {
3015                         if ((cap->issued & drop) &&
3016                             (cap->issued & unless) == 0) {
3017                                 dout("encode_inode_release %p cap %p %s -> "
3018                                      "%s\n", inode, cap,
3019                                      ceph_cap_string(cap->issued),
3020                                      ceph_cap_string(cap->issued & ~drop));
3021                                 cap->issued &= ~drop;
3022                                 cap->implemented &= ~drop;
3023                                 if (ci->i_ceph_flags & CEPH_I_NODELAY) {
3024                                         int wanted = __ceph_caps_wanted(ci);
3025                                         dout("  wanted %s -> %s (act %s)\n",
3026                                              ceph_cap_string(cap->mds_wanted),
3027                                              ceph_cap_string(cap->mds_wanted &
3028                                                              ~wanted),
3029                                              ceph_cap_string(wanted));
3030                                         cap->mds_wanted &= wanted;
3031                                 }
3032                         } else {
3033                                 dout("encode_inode_release %p cap %p %s"
3034                                      " (force)\n", inode, cap,
3035                                      ceph_cap_string(cap->issued));
3036                         }
3037 
3038                         rel->ino = cpu_to_le64(ceph_ino(inode));
3039                         rel->cap_id = cpu_to_le64(cap->cap_id);
3040                         rel->seq = cpu_to_le32(cap->seq);
3041                         rel->issue_seq = cpu_to_le32(cap->issue_seq),
3042                         rel->mseq = cpu_to_le32(cap->mseq);
3043                         rel->caps = cpu_to_le32(cap->issued);
3044                         rel->wanted = cpu_to_le32(cap->mds_wanted);
3045                         rel->dname_len = 0;
3046                         rel->dname_seq = 0;
3047                         *p += sizeof(*rel);
3048                         ret = 1;
3049                 } else {
3050                         dout("encode_inode_release %p cap %p %s\n",
3051                              inode, cap, ceph_cap_string(cap->issued));
3052                 }
3053         }
3054         spin_unlock(&ci->i_ceph_lock);
3055         return ret;
3056 }
3057 
3058 int ceph_encode_dentry_release(void **p, struct dentry *dentry,
3059                                int mds, int drop, int unless)
3060 {
3061         struct inode *dir = dentry->d_parent->d_inode;
3062         struct ceph_mds_request_release *rel = *p;
3063         struct ceph_dentry_info *di = ceph_dentry(dentry);
3064         int force = 0;
3065         int ret;
3066 
3067         /*
3068          * force an record for the directory caps if we have a dentry lease.
3069          * this is racy (can't take i_ceph_lock and d_lock together), but it
3070          * doesn't have to be perfect; the mds will revoke anything we don't
3071          * release.
3072          */
3073         spin_lock(&dentry->d_lock);
3074         if (di->lease_session && di->lease_session->s_mds == mds)
3075                 force = 1;
3076         spin_unlock(&dentry->d_lock);
3077 
3078         ret = ceph_encode_inode_release(p, dir, mds, drop, unless, force);
3079 
3080         spin_lock(&dentry->d_lock);
3081         if (ret && di->lease_session && di->lease_session->s_mds == mds) {
3082                 dout("encode_dentry_release %p mds%d seq %d\n",
3083                      dentry, mds, (int)di->lease_seq);
3084                 rel->dname_len = cpu_to_le32(dentry->d_name.len);
3085                 memcpy(*p, dentry->d_name.name, dentry->d_name.len);
3086                 *p += dentry->d_name.len;
3087                 rel->dname_seq = cpu_to_le32(di->lease_seq);
3088                 __ceph_mdsc_drop_dentry_lease(dentry);
3089         }
3090         spin_unlock(&dentry->d_lock);
3091         return ret;
3092 }
3093 

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