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1// SPDX-License-Identifier: GPL-2.02#include <linux/ceph/ceph_debug.h>3 4#include <linux/fs.h>5#include <linux/sort.h>6#include <linux/slab.h>7#include <linux/iversion.h>8#include "super.h"9#include "mds_client.h"10#include <linux/ceph/decode.h>11 12/* unused map expires after 5 minutes */13#define CEPH_SNAPID_MAP_TIMEOUT (5 * 60 * HZ)14 15/*16 * Snapshots in ceph are driven in large part by cooperation from the17 * client. In contrast to local file systems or file servers that18 * implement snapshots at a single point in the system, ceph's19 * distributed access to storage requires clients to help decide20 * whether a write logically occurs before or after a recently created21 * snapshot.22 *23 * This provides a perfect instantanous client-wide snapshot. Between24 * clients, however, snapshots may appear to be applied at slightly25 * different points in time, depending on delays in delivering the26 * snapshot notification.27 *28 * Snapshots are _not_ file system-wide. Instead, each snapshot29 * applies to the subdirectory nested beneath some directory. This30 * effectively divides the hierarchy into multiple "realms," where all31 * of the files contained by each realm share the same set of32 * snapshots. An individual realm's snap set contains snapshots33 * explicitly created on that realm, as well as any snaps in its34 * parent's snap set _after_ the point at which the parent became it's35 * parent (due to, say, a rename). Similarly, snaps from prior parents36 * during the time intervals during which they were the parent are included.37 *38 * The client is spared most of this detail, fortunately... it must only39 * maintains a hierarchy of realms reflecting the current parent/child40 * realm relationship, and for each realm has an explicit list of snaps41 * inherited from prior parents.42 *43 * A snap_realm struct is maintained for realms containing every inode44 * with an open cap in the system. (The needed snap realm information is45 * provided by the MDS whenever a cap is issued, i.e., on open.) A 'seq'46 * version number is used to ensure that as realm parameters change (new47 * snapshot, new parent, etc.) the client's realm hierarchy is updated.48 *49 * The realm hierarchy drives the generation of a 'snap context' for each50 * realm, which simply lists the resulting set of snaps for the realm. This51 * is attached to any writes sent to OSDs.52 */53/*54 * Unfortunately error handling is a bit mixed here. If we get a snap55 * update, but don't have enough memory to update our realm hierarchy,56 * it's not clear what we can do about it (besides complaining to the57 * console).58 */59 60 61/*62 * increase ref count for the realm63 *64 * caller must hold snap_rwsem.65 */66void ceph_get_snap_realm(struct ceph_mds_client *mdsc,67 struct ceph_snap_realm *realm)68{69 lockdep_assert_held(&mdsc->snap_rwsem);70 71 /*72 * The 0->1 and 1->0 transitions must take the snap_empty_lock73 * atomically with the refcount change. Go ahead and bump the74 * nref here, unless it's 0, in which case we take the spinlock75 * and then do the increment and remove it from the list.76 */77 if (atomic_inc_not_zero(&realm->nref))78 return;79 80 spin_lock(&mdsc->snap_empty_lock);81 if (atomic_inc_return(&realm->nref) == 1)82 list_del_init(&realm->empty_item);83 spin_unlock(&mdsc->snap_empty_lock);84}85 86static void __insert_snap_realm(struct rb_root *root,87 struct ceph_snap_realm *new)88{89 struct rb_node **p = &root->rb_node;90 struct rb_node *parent = NULL;91 struct ceph_snap_realm *r = NULL;92 93 while (*p) {94 parent = *p;95 r = rb_entry(parent, struct ceph_snap_realm, node);96 if (new->ino < r->ino)97 p = &(*p)->rb_left;98 else if (new->ino > r->ino)99 p = &(*p)->rb_right;100 else101 BUG();102 }103 104 rb_link_node(&new->node, parent, p);105 rb_insert_color(&new->node, root);106}107 108/*109 * create and get the realm rooted at @ino and bump its ref count.110 *111 * caller must hold snap_rwsem for write.112 */113static struct ceph_snap_realm *ceph_create_snap_realm(114 struct ceph_mds_client *mdsc,115 u64 ino)116{117 struct ceph_snap_realm *realm;118 119 lockdep_assert_held_write(&mdsc->snap_rwsem);120 121 realm = kzalloc(sizeof(*realm), GFP_NOFS);122 if (!realm)123 return ERR_PTR(-ENOMEM);124 125 /* Do not release the global dummy snaprealm until unmouting */126 if (ino == CEPH_INO_GLOBAL_SNAPREALM)127 atomic_set(&realm->nref, 2);128 else129 atomic_set(&realm->nref, 1);130 realm->ino = ino;131 INIT_LIST_HEAD(&realm->children);132 INIT_LIST_HEAD(&realm->child_item);133 INIT_LIST_HEAD(&realm->empty_item);134 INIT_LIST_HEAD(&realm->dirty_item);135 INIT_LIST_HEAD(&realm->rebuild_item);136 INIT_LIST_HEAD(&realm->inodes_with_caps);137 spin_lock_init(&realm->inodes_with_caps_lock);138 __insert_snap_realm(&mdsc->snap_realms, realm);139 mdsc->num_snap_realms++;140 141 doutc(mdsc->fsc->client, "%llx %p\n", realm->ino, realm);142 return realm;143}144 145/*146 * lookup the realm rooted at @ino.147 *148 * caller must hold snap_rwsem.149 */150static struct ceph_snap_realm *__lookup_snap_realm(struct ceph_mds_client *mdsc,151 u64 ino)152{153 struct ceph_client *cl = mdsc->fsc->client;154 struct rb_node *n = mdsc->snap_realms.rb_node;155 struct ceph_snap_realm *r;156 157 lockdep_assert_held(&mdsc->snap_rwsem);158 159 while (n) {160 r = rb_entry(n, struct ceph_snap_realm, node);161 if (ino < r->ino)162 n = n->rb_left;163 else if (ino > r->ino)164 n = n->rb_right;165 else {166 doutc(cl, "%llx %p\n", r->ino, r);167 return r;168 }169 }170 return NULL;171}172 173struct ceph_snap_realm *ceph_lookup_snap_realm(struct ceph_mds_client *mdsc,174 u64 ino)175{176 struct ceph_snap_realm *r;177 r = __lookup_snap_realm(mdsc, ino);178 if (r)179 ceph_get_snap_realm(mdsc, r);180 return r;181}182 183static void __put_snap_realm(struct ceph_mds_client *mdsc,184 struct ceph_snap_realm *realm);185 186/*187 * called with snap_rwsem (write)188 */189static void __destroy_snap_realm(struct ceph_mds_client *mdsc,190 struct ceph_snap_realm *realm)191{192 struct ceph_client *cl = mdsc->fsc->client;193 lockdep_assert_held_write(&mdsc->snap_rwsem);194 195 doutc(cl, "%p %llx\n", realm, realm->ino);196 197 rb_erase(&realm->node, &mdsc->snap_realms);198 mdsc->num_snap_realms--;199 200 if (realm->parent) {201 list_del_init(&realm->child_item);202 __put_snap_realm(mdsc, realm->parent);203 }204 205 kfree(realm->prior_parent_snaps);206 kfree(realm->snaps);207 ceph_put_snap_context(realm->cached_context);208 kfree(realm);209}210 211/*212 * caller holds snap_rwsem (write)213 */214static void __put_snap_realm(struct ceph_mds_client *mdsc,215 struct ceph_snap_realm *realm)216{217 lockdep_assert_held_write(&mdsc->snap_rwsem);218 219 /*220 * We do not require the snap_empty_lock here, as any caller that221 * increments the value must hold the snap_rwsem.222 */223 if (atomic_dec_and_test(&realm->nref))224 __destroy_snap_realm(mdsc, realm);225}226 227/*228 * See comments in ceph_get_snap_realm. Caller needn't hold any locks.229 */230void ceph_put_snap_realm(struct ceph_mds_client *mdsc,231 struct ceph_snap_realm *realm)232{233 if (!atomic_dec_and_lock(&realm->nref, &mdsc->snap_empty_lock))234 return;235 236 if (down_write_trylock(&mdsc->snap_rwsem)) {237 spin_unlock(&mdsc->snap_empty_lock);238 __destroy_snap_realm(mdsc, realm);239 up_write(&mdsc->snap_rwsem);240 } else {241 list_add(&realm->empty_item, &mdsc->snap_empty);242 spin_unlock(&mdsc->snap_empty_lock);243 }244}245 246/*247 * Clean up any realms whose ref counts have dropped to zero. Note248 * that this does not include realms who were created but not yet249 * used.250 *251 * Called under snap_rwsem (write)252 */253static void __cleanup_empty_realms(struct ceph_mds_client *mdsc)254{255 struct ceph_snap_realm *realm;256 257 lockdep_assert_held_write(&mdsc->snap_rwsem);258 259 spin_lock(&mdsc->snap_empty_lock);260 while (!list_empty(&mdsc->snap_empty)) {261 realm = list_first_entry(&mdsc->snap_empty,262 struct ceph_snap_realm, empty_item);263 list_del(&realm->empty_item);264 spin_unlock(&mdsc->snap_empty_lock);265 __destroy_snap_realm(mdsc, realm);266 spin_lock(&mdsc->snap_empty_lock);267 }268 spin_unlock(&mdsc->snap_empty_lock);269}270 271void ceph_cleanup_global_and_empty_realms(struct ceph_mds_client *mdsc)272{273 struct ceph_snap_realm *global_realm;274 275 down_write(&mdsc->snap_rwsem);276 global_realm = __lookup_snap_realm(mdsc, CEPH_INO_GLOBAL_SNAPREALM);277 if (global_realm)278 ceph_put_snap_realm(mdsc, global_realm);279 __cleanup_empty_realms(mdsc);280 up_write(&mdsc->snap_rwsem);281}282 283/*284 * adjust the parent realm of a given @realm. adjust child list, and parent285 * pointers, and ref counts appropriately.286 *287 * return true if parent was changed, 0 if unchanged, <0 on error.288 *289 * caller must hold snap_rwsem for write.290 */291static int adjust_snap_realm_parent(struct ceph_mds_client *mdsc,292 struct ceph_snap_realm *realm,293 u64 parentino)294{295 struct ceph_client *cl = mdsc->fsc->client;296 struct ceph_snap_realm *parent;297 298 lockdep_assert_held_write(&mdsc->snap_rwsem);299 300 if (realm->parent_ino == parentino)301 return 0;302 303 parent = ceph_lookup_snap_realm(mdsc, parentino);304 if (!parent) {305 parent = ceph_create_snap_realm(mdsc, parentino);306 if (IS_ERR(parent))307 return PTR_ERR(parent);308 }309 doutc(cl, "%llx %p: %llx %p -> %llx %p\n", realm->ino, realm,310 realm->parent_ino, realm->parent, parentino, parent);311 if (realm->parent) {312 list_del_init(&realm->child_item);313 ceph_put_snap_realm(mdsc, realm->parent);314 }315 realm->parent_ino = parentino;316 realm->parent = parent;317 list_add(&realm->child_item, &parent->children);318 return 1;319}320 321 322static int cmpu64_rev(const void *a, const void *b)323{324 if (*(u64 *)a < *(u64 *)b)325 return 1;326 if (*(u64 *)a > *(u64 *)b)327 return -1;328 return 0;329}330 331 332/*333 * build the snap context for a given realm.334 */335static int build_snap_context(struct ceph_mds_client *mdsc,336 struct ceph_snap_realm *realm,337 struct list_head *realm_queue,338 struct list_head *dirty_realms)339{340 struct ceph_client *cl = mdsc->fsc->client;341 struct ceph_snap_realm *parent = realm->parent;342 struct ceph_snap_context *snapc;343 int err = 0;344 u32 num = realm->num_prior_parent_snaps + realm->num_snaps;345 346 /*347 * build parent context, if it hasn't been built.348 * conservatively estimate that all parent snaps might be349 * included by us.350 */351 if (parent) {352 if (!parent->cached_context) {353 /* add to the queue head */354 list_add(&parent->rebuild_item, realm_queue);355 return 1;356 }357 num += parent->cached_context->num_snaps;358 }359 360 /* do i actually need to update? not if my context seq361 matches realm seq, and my parents' does to. (this works362 because we rebuild_snap_realms() works _downward_ in363 hierarchy after each update.) */364 if (realm->cached_context &&365 realm->cached_context->seq == realm->seq &&366 (!parent ||367 realm->cached_context->seq >= parent->cached_context->seq)) {368 doutc(cl, "%llx %p: %p seq %lld (%u snaps) (unchanged)\n",369 realm->ino, realm, realm->cached_context,370 realm->cached_context->seq,371 (unsigned int)realm->cached_context->num_snaps);372 return 0;373 }374 375 /* alloc new snap context */376 err = -ENOMEM;377 if (num > (SIZE_MAX - sizeof(*snapc)) / sizeof(u64))378 goto fail;379 snapc = ceph_create_snap_context(num, GFP_NOFS);380 if (!snapc)381 goto fail;382 383 /* build (reverse sorted) snap vector */384 num = 0;385 snapc->seq = realm->seq;386 if (parent) {387 u32 i;388 389 /* include any of parent's snaps occurring _after_ my390 parent became my parent */391 for (i = 0; i < parent->cached_context->num_snaps; i++)392 if (parent->cached_context->snaps[i] >=393 realm->parent_since)394 snapc->snaps[num++] =395 parent->cached_context->snaps[i];396 if (parent->cached_context->seq > snapc->seq)397 snapc->seq = parent->cached_context->seq;398 }399 memcpy(snapc->snaps + num, realm->snaps,400 sizeof(u64)*realm->num_snaps);401 num += realm->num_snaps;402 memcpy(snapc->snaps + num, realm->prior_parent_snaps,403 sizeof(u64)*realm->num_prior_parent_snaps);404 num += realm->num_prior_parent_snaps;405 406 sort(snapc->snaps, num, sizeof(u64), cmpu64_rev, NULL);407 snapc->num_snaps = num;408 doutc(cl, "%llx %p: %p seq %lld (%u snaps)\n", realm->ino, realm,409 snapc, snapc->seq, (unsigned int) snapc->num_snaps);410 411 ceph_put_snap_context(realm->cached_context);412 realm->cached_context = snapc;413 /* queue realm for cap_snap creation */414 list_add_tail(&realm->dirty_item, dirty_realms);415 return 0;416 417fail:418 /*419 * if we fail, clear old (incorrect) cached_context... hopefully420 * we'll have better luck building it later421 */422 if (realm->cached_context) {423 ceph_put_snap_context(realm->cached_context);424 realm->cached_context = NULL;425 }426 pr_err_client(cl, "%llx %p fail %d\n", realm->ino, realm, err);427 return err;428}429 430/*431 * rebuild snap context for the given realm and all of its children.432 */433static void rebuild_snap_realms(struct ceph_mds_client *mdsc,434 struct ceph_snap_realm *realm,435 struct list_head *dirty_realms)436{437 struct ceph_client *cl = mdsc->fsc->client;438 LIST_HEAD(realm_queue);439 int last = 0;440 bool skip = false;441 442 list_add_tail(&realm->rebuild_item, &realm_queue);443 444 while (!list_empty(&realm_queue)) {445 struct ceph_snap_realm *_realm, *child;446 447 _realm = list_first_entry(&realm_queue,448 struct ceph_snap_realm,449 rebuild_item);450 451 /*452 * If the last building failed dues to memory453 * issue, just empty the realm_queue and return454 * to avoid infinite loop.455 */456 if (last < 0) {457 list_del_init(&_realm->rebuild_item);458 continue;459 }460 461 last = build_snap_context(mdsc, _realm, &realm_queue,462 dirty_realms);463 doutc(cl, "%llx %p, %s\n", realm->ino, realm,464 last > 0 ? "is deferred" : !last ? "succeeded" : "failed");465 466 /* is any child in the list ? */467 list_for_each_entry(child, &_realm->children, child_item) {468 if (!list_empty(&child->rebuild_item)) {469 skip = true;470 break;471 }472 }473 474 if (!skip) {475 list_for_each_entry(child, &_realm->children, child_item)476 list_add_tail(&child->rebuild_item, &realm_queue);477 }478 479 /* last == 1 means need to build parent first */480 if (last <= 0)481 list_del_init(&_realm->rebuild_item);482 }483}484 485 486/*487 * helper to allocate and decode an array of snapids. free prior488 * instance, if any.489 */490static int dup_array(u64 **dst, __le64 *src, u32 num)491{492 u32 i;493 494 kfree(*dst);495 if (num) {496 *dst = kcalloc(num, sizeof(u64), GFP_NOFS);497 if (!*dst)498 return -ENOMEM;499 for (i = 0; i < num; i++)500 (*dst)[i] = get_unaligned_le64(src + i);501 } else {502 *dst = NULL;503 }504 return 0;505}506 507static bool has_new_snaps(struct ceph_snap_context *o,508 struct ceph_snap_context *n)509{510 if (n->num_snaps == 0)511 return false;512 /* snaps are in descending order */513 return n->snaps[0] > o->seq;514}515 516/*517 * When a snapshot is applied, the size/mtime inode metadata is queued518 * in a ceph_cap_snap (one for each snapshot) until writeback519 * completes and the metadata can be flushed back to the MDS.520 *521 * However, if a (sync) write is currently in-progress when we apply522 * the snapshot, we have to wait until the write succeeds or fails523 * (and a final size/mtime is known). In this case the524 * cap_snap->writing = 1, and is said to be "pending." When the write525 * finishes, we __ceph_finish_cap_snap().526 *527 * Caller must hold snap_rwsem for read (i.e., the realm topology won't528 * change).529 */530static void ceph_queue_cap_snap(struct ceph_inode_info *ci,531 struct ceph_cap_snap **pcapsnap)532{533 struct inode *inode = &ci->netfs.inode;534 struct ceph_client *cl = ceph_inode_to_client(inode);535 struct ceph_snap_context *old_snapc, *new_snapc;536 struct ceph_cap_snap *capsnap = *pcapsnap;537 struct ceph_buffer *old_blob = NULL;538 int used, dirty;539 540 spin_lock(&ci->i_ceph_lock);541 used = __ceph_caps_used(ci);542 dirty = __ceph_caps_dirty(ci);543 544 old_snapc = ci->i_head_snapc;545 new_snapc = ci->i_snap_realm->cached_context;546 547 /*548 * If there is a write in progress, treat that as a dirty Fw,549 * even though it hasn't completed yet; by the time we finish550 * up this capsnap it will be.551 */552 if (used & CEPH_CAP_FILE_WR)553 dirty |= CEPH_CAP_FILE_WR;554 555 if (__ceph_have_pending_cap_snap(ci)) {556 /* there is no point in queuing multiple "pending" cap_snaps,557 as no new writes are allowed to start when pending, so any558 writes in progress now were started before the previous559 cap_snap. lucky us. */560 doutc(cl, "%p %llx.%llx already pending\n", inode,561 ceph_vinop(inode));562 goto update_snapc;563 }564 if (ci->i_wrbuffer_ref_head == 0 &&565 !(dirty & (CEPH_CAP_ANY_EXCL|CEPH_CAP_FILE_WR))) {566 doutc(cl, "%p %llx.%llx nothing dirty|writing\n", inode,567 ceph_vinop(inode));568 goto update_snapc;569 }570 571 BUG_ON(!old_snapc);572 573 /*574 * There is no need to send FLUSHSNAP message to MDS if there is575 * no new snapshot. But when there is dirty pages or on-going576 * writes, we still need to create cap_snap. cap_snap is needed577 * by the write path and page writeback path.578 *579 * also see ceph_try_drop_cap_snap()580 */581 if (has_new_snaps(old_snapc, new_snapc)) {582 if (dirty & (CEPH_CAP_ANY_EXCL|CEPH_CAP_FILE_WR))583 capsnap->need_flush = true;584 } else {585 if (!(used & CEPH_CAP_FILE_WR) &&586 ci->i_wrbuffer_ref_head == 0) {587 doutc(cl, "%p %llx.%llx no new_snap|dirty_page|writing\n",588 inode, ceph_vinop(inode));589 goto update_snapc;590 }591 }592 593 doutc(cl, "%p %llx.%llx cap_snap %p queuing under %p %s %s\n",594 inode, ceph_vinop(inode), capsnap, old_snapc,595 ceph_cap_string(dirty), capsnap->need_flush ? "" : "no_flush");596 ihold(inode);597 598 capsnap->follows = old_snapc->seq;599 capsnap->issued = __ceph_caps_issued(ci, NULL);600 capsnap->dirty = dirty;601 602 capsnap->mode = inode->i_mode;603 capsnap->uid = inode->i_uid;604 capsnap->gid = inode->i_gid;605 606 if (dirty & CEPH_CAP_XATTR_EXCL) {607 old_blob = __ceph_build_xattrs_blob(ci);608 capsnap->xattr_blob =609 ceph_buffer_get(ci->i_xattrs.blob);610 capsnap->xattr_version = ci->i_xattrs.version;611 } else {612 capsnap->xattr_blob = NULL;613 capsnap->xattr_version = 0;614 }615 616 capsnap->inline_data = ci->i_inline_version != CEPH_INLINE_NONE;617 618 /* dirty page count moved from _head to this cap_snap;619 all subsequent writes page dirties occur _after_ this620 snapshot. */621 capsnap->dirty_pages = ci->i_wrbuffer_ref_head;622 ci->i_wrbuffer_ref_head = 0;623 capsnap->context = old_snapc;624 list_add_tail(&capsnap->ci_item, &ci->i_cap_snaps);625 626 if (used & CEPH_CAP_FILE_WR) {627 doutc(cl, "%p %llx.%llx cap_snap %p snapc %p seq %llu used WR,"628 " now pending\n", inode, ceph_vinop(inode), capsnap,629 old_snapc, old_snapc->seq);630 capsnap->writing = 1;631 } else {632 /* note mtime, size NOW. */633 __ceph_finish_cap_snap(ci, capsnap);634 }635 *pcapsnap = NULL;636 old_snapc = NULL;637 638update_snapc:639 if (ci->i_wrbuffer_ref_head == 0 &&640 ci->i_wr_ref == 0 &&641 ci->i_dirty_caps == 0 &&642 ci->i_flushing_caps == 0) {643 ci->i_head_snapc = NULL;644 } else {645 ci->i_head_snapc = ceph_get_snap_context(new_snapc);646 doutc(cl, " new snapc is %p\n", new_snapc);647 }648 spin_unlock(&ci->i_ceph_lock);649 650 ceph_buffer_put(old_blob);651 ceph_put_snap_context(old_snapc);652}653 654/*655 * Finalize the size, mtime for a cap_snap.. that is, settle on final values656 * to be used for the snapshot, to be flushed back to the mds.657 *658 * If capsnap can now be flushed, add to snap_flush list, and return 1.659 *660 * Caller must hold i_ceph_lock.661 */662int __ceph_finish_cap_snap(struct ceph_inode_info *ci,663 struct ceph_cap_snap *capsnap)664{665 struct inode *inode = &ci->netfs.inode;666 struct ceph_mds_client *mdsc = ceph_sb_to_mdsc(inode->i_sb);667 struct ceph_client *cl = mdsc->fsc->client;668 669 BUG_ON(capsnap->writing);670 capsnap->size = i_size_read(inode);671 capsnap->mtime = inode_get_mtime(inode);672 capsnap->atime = inode_get_atime(inode);673 capsnap->ctime = inode_get_ctime(inode);674 capsnap->btime = ci->i_btime;675 capsnap->change_attr = inode_peek_iversion_raw(inode);676 capsnap->time_warp_seq = ci->i_time_warp_seq;677 capsnap->truncate_size = ci->i_truncate_size;678 capsnap->truncate_seq = ci->i_truncate_seq;679 if (capsnap->dirty_pages) {680 doutc(cl, "%p %llx.%llx cap_snap %p snapc %p %llu %s "681 "s=%llu still has %d dirty pages\n", inode,682 ceph_vinop(inode), capsnap, capsnap->context,683 capsnap->context->seq,684 ceph_cap_string(capsnap->dirty),685 capsnap->size, capsnap->dirty_pages);686 return 0;687 }688 689 /*690 * Defer flushing the capsnap if the dirty buffer not flushed yet.691 * And trigger to flush the buffer immediately.692 */693 if (ci->i_wrbuffer_ref) {694 doutc(cl, "%p %llx.%llx cap_snap %p snapc %p %llu %s "695 "s=%llu used WRBUFFER, delaying\n", inode,696 ceph_vinop(inode), capsnap, capsnap->context,697 capsnap->context->seq, ceph_cap_string(capsnap->dirty),698 capsnap->size);699 ceph_queue_writeback(inode);700 return 0;701 }702 703 ci->i_ceph_flags |= CEPH_I_FLUSH_SNAPS;704 doutc(cl, "%p %llx.%llx cap_snap %p snapc %p %llu %s s=%llu\n",705 inode, ceph_vinop(inode), capsnap, capsnap->context,706 capsnap->context->seq, ceph_cap_string(capsnap->dirty),707 capsnap->size);708 709 spin_lock(&mdsc->snap_flush_lock);710 if (list_empty(&ci->i_snap_flush_item)) {711 ihold(inode);712 list_add_tail(&ci->i_snap_flush_item, &mdsc->snap_flush_list);713 }714 spin_unlock(&mdsc->snap_flush_lock);715 return 1; /* caller may want to ceph_flush_snaps */716}717 718/*719 * Queue cap_snaps for snap writeback for this realm and its children.720 * Called under snap_rwsem, so realm topology won't change.721 */722static void queue_realm_cap_snaps(struct ceph_mds_client *mdsc,723 struct ceph_snap_realm *realm)724{725 struct ceph_client *cl = mdsc->fsc->client;726 struct ceph_inode_info *ci;727 struct inode *lastinode = NULL;728 struct ceph_cap_snap *capsnap = NULL;729 730 doutc(cl, "%p %llx inode\n", realm, realm->ino);731 732 spin_lock(&realm->inodes_with_caps_lock);733 list_for_each_entry(ci, &realm->inodes_with_caps, i_snap_realm_item) {734 struct inode *inode = igrab(&ci->netfs.inode);735 if (!inode)736 continue;737 spin_unlock(&realm->inodes_with_caps_lock);738 iput(lastinode);739 lastinode = inode;740 741 /*742 * Allocate the capsnap memory outside of ceph_queue_cap_snap()743 * to reduce very possible but unnecessary frequently memory744 * allocate/free in this loop.745 */746 if (!capsnap) {747 capsnap = kmem_cache_zalloc(ceph_cap_snap_cachep, GFP_NOFS);748 if (!capsnap) {749 pr_err_client(cl,750 "ENOMEM allocating ceph_cap_snap on %p\n",751 inode);752 return;753 }754 }755 capsnap->cap_flush.is_capsnap = true;756 refcount_set(&capsnap->nref, 1);757 INIT_LIST_HEAD(&capsnap->cap_flush.i_list);758 INIT_LIST_HEAD(&capsnap->cap_flush.g_list);759 INIT_LIST_HEAD(&capsnap->ci_item);760 761 ceph_queue_cap_snap(ci, &capsnap);762 spin_lock(&realm->inodes_with_caps_lock);763 }764 spin_unlock(&realm->inodes_with_caps_lock);765 iput(lastinode);766 767 if (capsnap)768 kmem_cache_free(ceph_cap_snap_cachep, capsnap);769 doutc(cl, "%p %llx done\n", realm, realm->ino);770}771 772/*773 * Parse and apply a snapblob "snap trace" from the MDS. This specifies774 * the snap realm parameters from a given realm and all of its ancestors,775 * up to the root.776 *777 * Caller must hold snap_rwsem for write.778 */779int ceph_update_snap_trace(struct ceph_mds_client *mdsc,780 void *p, void *e, bool deletion,781 struct ceph_snap_realm **realm_ret)782{783 struct ceph_client *cl = mdsc->fsc->client;784 struct ceph_mds_snap_realm *ri; /* encoded */785 __le64 *snaps; /* encoded */786 __le64 *prior_parent_snaps; /* encoded */787 struct ceph_snap_realm *realm;788 struct ceph_snap_realm *first_realm = NULL;789 struct ceph_snap_realm *realm_to_rebuild = NULL;790 struct ceph_client *client = mdsc->fsc->client;791 int rebuild_snapcs;792 int err = -ENOMEM;793 int ret;794 LIST_HEAD(dirty_realms);795 796 lockdep_assert_held_write(&mdsc->snap_rwsem);797 798 doutc(cl, "deletion=%d\n", deletion);799more:800 realm = NULL;801 rebuild_snapcs = 0;802 ceph_decode_need(&p, e, sizeof(*ri), bad);803 ri = p;804 p += sizeof(*ri);805 ceph_decode_need(&p, e, sizeof(u64)*(le32_to_cpu(ri->num_snaps) +806 le32_to_cpu(ri->num_prior_parent_snaps)), bad);807 snaps = p;808 p += sizeof(u64) * le32_to_cpu(ri->num_snaps);809 prior_parent_snaps = p;810 p += sizeof(u64) * le32_to_cpu(ri->num_prior_parent_snaps);811 812 realm = ceph_lookup_snap_realm(mdsc, le64_to_cpu(ri->ino));813 if (!realm) {814 realm = ceph_create_snap_realm(mdsc, le64_to_cpu(ri->ino));815 if (IS_ERR(realm)) {816 err = PTR_ERR(realm);817 goto fail;818 }819 }820 821 /* ensure the parent is correct */822 err = adjust_snap_realm_parent(mdsc, realm, le64_to_cpu(ri->parent));823 if (err < 0)824 goto fail;825 rebuild_snapcs += err;826 827 if (le64_to_cpu(ri->seq) > realm->seq) {828 doutc(cl, "updating %llx %p %lld -> %lld\n", realm->ino,829 realm, realm->seq, le64_to_cpu(ri->seq));830 /* update realm parameters, snap lists */831 realm->seq = le64_to_cpu(ri->seq);832 realm->created = le64_to_cpu(ri->created);833 realm->parent_since = le64_to_cpu(ri->parent_since);834 835 realm->num_snaps = le32_to_cpu(ri->num_snaps);836 err = dup_array(&realm->snaps, snaps, realm->num_snaps);837 if (err < 0)838 goto fail;839 840 realm->num_prior_parent_snaps =841 le32_to_cpu(ri->num_prior_parent_snaps);842 err = dup_array(&realm->prior_parent_snaps, prior_parent_snaps,843 realm->num_prior_parent_snaps);844 if (err < 0)845 goto fail;846 847 if (realm->seq > mdsc->last_snap_seq)848 mdsc->last_snap_seq = realm->seq;849 850 rebuild_snapcs = 1;851 } else if (!realm->cached_context) {852 doutc(cl, "%llx %p seq %lld new\n", realm->ino, realm,853 realm->seq);854 rebuild_snapcs = 1;855 } else {856 doutc(cl, "%llx %p seq %lld unchanged\n", realm->ino, realm,857 realm->seq);858 }859 860 doutc(cl, "done with %llx %p, rebuild_snapcs=%d, %p %p\n", realm->ino,861 realm, rebuild_snapcs, p, e);862 863 /*864 * this will always track the uppest parent realm from which865 * we need to rebuild the snapshot contexts _downward_ in866 * hierarchy.867 */868 if (rebuild_snapcs)869 realm_to_rebuild = realm;870 871 /* rebuild_snapcs when we reach the _end_ (root) of the trace */872 if (realm_to_rebuild && p >= e)873 rebuild_snap_realms(mdsc, realm_to_rebuild, &dirty_realms);874 875 if (!first_realm)876 first_realm = realm;877 else878 ceph_put_snap_realm(mdsc, realm);879 880 if (p < e)881 goto more;882 883 /*884 * queue cap snaps _after_ we've built the new snap contexts,885 * so that i_head_snapc can be set appropriately.886 */887 while (!list_empty(&dirty_realms)) {888 realm = list_first_entry(&dirty_realms, struct ceph_snap_realm,889 dirty_item);890 list_del_init(&realm->dirty_item);891 queue_realm_cap_snaps(mdsc, realm);892 }893 894 if (realm_ret)895 *realm_ret = first_realm;896 else897 ceph_put_snap_realm(mdsc, first_realm);898 899 __cleanup_empty_realms(mdsc);900 return 0;901 902bad:903 err = -EIO;904fail:905 if (realm && !IS_ERR(realm))906 ceph_put_snap_realm(mdsc, realm);907 if (first_realm)908 ceph_put_snap_realm(mdsc, first_realm);909 pr_err_client(cl, "error %d\n", err);910 911 /*912 * When receiving a corrupted snap trace we don't know what913 * exactly has happened in MDS side. And we shouldn't continue914 * writing to OSD, which may corrupt the snapshot contents.915 *916 * Just try to blocklist this kclient and then this kclient917 * must be remounted to continue after the corrupted metadata918 * fixed in the MDS side.919 */920 WRITE_ONCE(mdsc->fsc->mount_state, CEPH_MOUNT_FENCE_IO);921 ret = ceph_monc_blocklist_add(&client->monc, &client->msgr.inst.addr);922 if (ret)923 pr_err_client(cl, "failed to blocklist %s: %d\n",924 ceph_pr_addr(&client->msgr.inst.addr), ret);925 926 WARN(1, "[client.%lld] %s %s%sdo remount to continue%s",927 client->monc.auth->global_id, __func__,928 ret ? "" : ceph_pr_addr(&client->msgr.inst.addr),929 ret ? "" : " was blocklisted, ",930 err == -EIO ? " after corrupted snaptrace is fixed" : "");931 932 return err;933}934 935 936/*937 * Send any cap_snaps that are queued for flush. Try to carry938 * s_mutex across multiple snap flushes to avoid locking overhead.939 *940 * Caller holds no locks.941 */942static void flush_snaps(struct ceph_mds_client *mdsc)943{944 struct ceph_client *cl = mdsc->fsc->client;945 struct ceph_inode_info *ci;946 struct inode *inode;947 struct ceph_mds_session *session = NULL;948 949 doutc(cl, "begin\n");950 spin_lock(&mdsc->snap_flush_lock);951 while (!list_empty(&mdsc->snap_flush_list)) {952 ci = list_first_entry(&mdsc->snap_flush_list,953 struct ceph_inode_info, i_snap_flush_item);954 inode = &ci->netfs.inode;955 ihold(inode);956 spin_unlock(&mdsc->snap_flush_lock);957 ceph_flush_snaps(ci, &session);958 iput(inode);959 spin_lock(&mdsc->snap_flush_lock);960 }961 spin_unlock(&mdsc->snap_flush_lock);962 963 ceph_put_mds_session(session);964 doutc(cl, "done\n");965}966 967/**968 * ceph_change_snap_realm - change the snap_realm for an inode969 * @inode: inode to move to new snap realm970 * @realm: new realm to move inode into (may be NULL)971 *972 * Detach an inode from its old snaprealm (if any) and attach it to973 * the new snaprealm (if any). The old snap realm reference held by974 * the inode is put. If realm is non-NULL, then the caller's reference975 * to it is taken over by the inode.976 */977void ceph_change_snap_realm(struct inode *inode, struct ceph_snap_realm *realm)978{979 struct ceph_inode_info *ci = ceph_inode(inode);980 struct ceph_mds_client *mdsc = ceph_inode_to_fs_client(inode)->mdsc;981 struct ceph_snap_realm *oldrealm = ci->i_snap_realm;982 983 lockdep_assert_held(&ci->i_ceph_lock);984 985 if (oldrealm) {986 spin_lock(&oldrealm->inodes_with_caps_lock);987 list_del_init(&ci->i_snap_realm_item);988 if (oldrealm->ino == ci->i_vino.ino)989 oldrealm->inode = NULL;990 spin_unlock(&oldrealm->inodes_with_caps_lock);991 ceph_put_snap_realm(mdsc, oldrealm);992 }993 994 ci->i_snap_realm = realm;995 996 if (realm) {997 spin_lock(&realm->inodes_with_caps_lock);998 list_add(&ci->i_snap_realm_item, &realm->inodes_with_caps);999 if (realm->ino == ci->i_vino.ino)1000 realm->inode = inode;1001 spin_unlock(&realm->inodes_with_caps_lock);1002 }1003}1004 1005/*1006 * Handle a snap notification from the MDS.1007 *1008 * This can take two basic forms: the simplest is just a snap creation1009 * or deletion notification on an existing realm. This should update the1010 * realm and its children.1011 *1012 * The more difficult case is realm creation, due to snap creation at a1013 * new point in the file hierarchy, or due to a rename that moves a file or1014 * directory into another realm.1015 */1016void ceph_handle_snap(struct ceph_mds_client *mdsc,1017 struct ceph_mds_session *session,1018 struct ceph_msg *msg)1019{1020 struct ceph_client *cl = mdsc->fsc->client;1021 struct super_block *sb = mdsc->fsc->sb;1022 int mds = session->s_mds;1023 u64 split;1024 int op;1025 int trace_len;1026 struct ceph_snap_realm *realm = NULL;1027 void *p = msg->front.iov_base;1028 void *e = p + msg->front.iov_len;1029 struct ceph_mds_snap_head *h;1030 int num_split_inos, num_split_realms;1031 __le64 *split_inos = NULL, *split_realms = NULL;1032 int i;1033 int locked_rwsem = 0;1034 bool close_sessions = false;1035 1036 if (!ceph_inc_mds_stopping_blocker(mdsc, session))1037 return;1038 1039 /* decode */1040 if (msg->front.iov_len < sizeof(*h))1041 goto bad;1042 h = p;1043 op = le32_to_cpu(h->op);1044 split = le64_to_cpu(h->split); /* non-zero if we are splitting an1045 * existing realm */1046 num_split_inos = le32_to_cpu(h->num_split_inos);1047 num_split_realms = le32_to_cpu(h->num_split_realms);1048 trace_len = le32_to_cpu(h->trace_len);1049 p += sizeof(*h);1050 1051 doutc(cl, "from mds%d op %s split %llx tracelen %d\n", mds,1052 ceph_snap_op_name(op), split, trace_len);1053 1054 down_write(&mdsc->snap_rwsem);1055 locked_rwsem = 1;1056 1057 if (op == CEPH_SNAP_OP_SPLIT) {1058 struct ceph_mds_snap_realm *ri;1059 1060 /*1061 * A "split" breaks part of an existing realm off into1062 * a new realm. The MDS provides a list of inodes1063 * (with caps) and child realms that belong to the new1064 * child.1065 */1066 split_inos = p;1067 p += sizeof(u64) * num_split_inos;1068 split_realms = p;1069 p += sizeof(u64) * num_split_realms;1070 ceph_decode_need(&p, e, sizeof(*ri), bad);1071 /* we will peek at realm info here, but will _not_1072 * advance p, as the realm update will occur below in1073 * ceph_update_snap_trace. */1074 ri = p;1075 1076 realm = ceph_lookup_snap_realm(mdsc, split);1077 if (!realm) {1078 realm = ceph_create_snap_realm(mdsc, split);1079 if (IS_ERR(realm))1080 goto out;1081 }1082 1083 doutc(cl, "splitting snap_realm %llx %p\n", realm->ino, realm);1084 for (i = 0; i < num_split_inos; i++) {1085 struct ceph_vino vino = {1086 .ino = le64_to_cpu(split_inos[i]),1087 .snap = CEPH_NOSNAP,1088 };1089 struct inode *inode = ceph_find_inode(sb, vino);1090 struct ceph_inode_info *ci;1091 1092 if (!inode)1093 continue;1094 ci = ceph_inode(inode);1095 1096 spin_lock(&ci->i_ceph_lock);1097 if (!ci->i_snap_realm)1098 goto skip_inode;1099 /*1100 * If this inode belongs to a realm that was1101 * created after our new realm, we experienced1102 * a race (due to another split notifications1103 * arriving from a different MDS). So skip1104 * this inode.1105 */1106 if (ci->i_snap_realm->created >1107 le64_to_cpu(ri->created)) {1108 doutc(cl, " leaving %p %llx.%llx in newer realm %llx %p\n",1109 inode, ceph_vinop(inode), ci->i_snap_realm->ino,1110 ci->i_snap_realm);1111 goto skip_inode;1112 }1113 doutc(cl, " will move %p %llx.%llx to split realm %llx %p\n",1114 inode, ceph_vinop(inode), realm->ino, realm);1115 1116 ceph_get_snap_realm(mdsc, realm);1117 ceph_change_snap_realm(inode, realm);1118 spin_unlock(&ci->i_ceph_lock);1119 iput(inode);1120 continue;1121 1122skip_inode:1123 spin_unlock(&ci->i_ceph_lock);1124 iput(inode);1125 }1126 1127 /* we may have taken some of the old realm's children. */1128 for (i = 0; i < num_split_realms; i++) {1129 struct ceph_snap_realm *child =1130 __lookup_snap_realm(mdsc,1131 le64_to_cpu(split_realms[i]));1132 if (!child)1133 continue;1134 adjust_snap_realm_parent(mdsc, child, realm->ino);1135 }1136 } else {1137 /*1138 * In the non-split case both 'num_split_inos' and1139 * 'num_split_realms' should be 0, making this a no-op.1140 * However the MDS happens to populate 'split_realms' list1141 * in one of the UPDATE op cases by mistake.1142 *1143 * Skip both lists just in case to ensure that 'p' is1144 * positioned at the start of realm info, as expected by1145 * ceph_update_snap_trace().1146 */1147 p += sizeof(u64) * num_split_inos;1148 p += sizeof(u64) * num_split_realms;1149 }1150 1151 /*1152 * update using the provided snap trace. if we are deleting a1153 * snap, we can avoid queueing cap_snaps.1154 */1155 if (ceph_update_snap_trace(mdsc, p, e,1156 op == CEPH_SNAP_OP_DESTROY,1157 NULL)) {1158 close_sessions = true;1159 goto bad;1160 }1161 1162 if (op == CEPH_SNAP_OP_SPLIT)1163 /* we took a reference when we created the realm, above */1164 ceph_put_snap_realm(mdsc, realm);1165 1166 __cleanup_empty_realms(mdsc);1167 1168 up_write(&mdsc->snap_rwsem);1169 1170 flush_snaps(mdsc);1171 ceph_dec_mds_stopping_blocker(mdsc);1172 return;1173 1174bad:1175 pr_err_client(cl, "corrupt snap message from mds%d\n", mds);1176 ceph_msg_dump(msg);1177out:1178 if (locked_rwsem)1179 up_write(&mdsc->snap_rwsem);1180 1181 ceph_dec_mds_stopping_blocker(mdsc);1182 1183 if (close_sessions)1184 ceph_mdsc_close_sessions(mdsc);1185 return;1186}1187 1188struct ceph_snapid_map* ceph_get_snapid_map(struct ceph_mds_client *mdsc,1189 u64 snap)1190{1191 struct ceph_client *cl = mdsc->fsc->client;1192 struct ceph_snapid_map *sm, *exist;1193 struct rb_node **p, *parent;1194 int ret;1195 1196 exist = NULL;1197 spin_lock(&mdsc->snapid_map_lock);1198 p = &mdsc->snapid_map_tree.rb_node;1199 while (*p) {1200 exist = rb_entry(*p, struct ceph_snapid_map, node);1201 if (snap > exist->snap) {1202 p = &(*p)->rb_left;1203 } else if (snap < exist->snap) {1204 p = &(*p)->rb_right;1205 } else {1206 if (atomic_inc_return(&exist->ref) == 1)1207 list_del_init(&exist->lru);1208 break;1209 }1210 exist = NULL;1211 }1212 spin_unlock(&mdsc->snapid_map_lock);1213 if (exist) {1214 doutc(cl, "found snapid map %llx -> %x\n", exist->snap,1215 exist->dev);1216 return exist;1217 }1218 1219 sm = kmalloc(sizeof(*sm), GFP_NOFS);1220 if (!sm)1221 return NULL;1222 1223 ret = get_anon_bdev(&sm->dev);1224 if (ret < 0) {1225 kfree(sm);1226 return NULL;1227 }1228 1229 INIT_LIST_HEAD(&sm->lru);1230 atomic_set(&sm->ref, 1);1231 sm->snap = snap;1232 1233 exist = NULL;1234 parent = NULL;1235 p = &mdsc->snapid_map_tree.rb_node;1236 spin_lock(&mdsc->snapid_map_lock);1237 while (*p) {1238 parent = *p;1239 exist = rb_entry(*p, struct ceph_snapid_map, node);1240 if (snap > exist->snap)1241 p = &(*p)->rb_left;1242 else if (snap < exist->snap)1243 p = &(*p)->rb_right;1244 else1245 break;1246 exist = NULL;1247 }1248 if (exist) {1249 if (atomic_inc_return(&exist->ref) == 1)1250 list_del_init(&exist->lru);1251 } else {1252 rb_link_node(&sm->node, parent, p);1253 rb_insert_color(&sm->node, &mdsc->snapid_map_tree);1254 }1255 spin_unlock(&mdsc->snapid_map_lock);1256 if (exist) {1257 free_anon_bdev(sm->dev);1258 kfree(sm);1259 doutc(cl, "found snapid map %llx -> %x\n", exist->snap,1260 exist->dev);1261 return exist;1262 }1263 1264 doutc(cl, "create snapid map %llx -> %x\n", sm->snap, sm->dev);1265 return sm;1266}1267 1268void ceph_put_snapid_map(struct ceph_mds_client* mdsc,1269 struct ceph_snapid_map *sm)1270{1271 if (!sm)1272 return;1273 if (atomic_dec_and_lock(&sm->ref, &mdsc->snapid_map_lock)) {1274 if (!RB_EMPTY_NODE(&sm->node)) {1275 sm->last_used = jiffies;1276 list_add_tail(&sm->lru, &mdsc->snapid_map_lru);1277 spin_unlock(&mdsc->snapid_map_lock);1278 } else {1279 /* already cleaned up by1280 * ceph_cleanup_snapid_map() */1281 spin_unlock(&mdsc->snapid_map_lock);1282 kfree(sm);1283 }1284 }1285}1286 1287void ceph_trim_snapid_map(struct ceph_mds_client *mdsc)1288{1289 struct ceph_client *cl = mdsc->fsc->client;1290 struct ceph_snapid_map *sm;1291 unsigned long now;1292 LIST_HEAD(to_free);1293 1294 spin_lock(&mdsc->snapid_map_lock);1295 now = jiffies;1296 1297 while (!list_empty(&mdsc->snapid_map_lru)) {1298 sm = list_first_entry(&mdsc->snapid_map_lru,1299 struct ceph_snapid_map, lru);1300 if (time_after(sm->last_used + CEPH_SNAPID_MAP_TIMEOUT, now))1301 break;1302 1303 rb_erase(&sm->node, &mdsc->snapid_map_tree);1304 list_move(&sm->lru, &to_free);1305 }1306 spin_unlock(&mdsc->snapid_map_lock);1307 1308 while (!list_empty(&to_free)) {1309 sm = list_first_entry(&to_free, struct ceph_snapid_map, lru);1310 list_del(&sm->lru);1311 doutc(cl, "trim snapid map %llx -> %x\n", sm->snap, sm->dev);1312 free_anon_bdev(sm->dev);1313 kfree(sm);1314 }1315}1316 1317void ceph_cleanup_snapid_map(struct ceph_mds_client *mdsc)1318{1319 struct ceph_client *cl = mdsc->fsc->client;1320 struct ceph_snapid_map *sm;1321 struct rb_node *p;1322 LIST_HEAD(to_free);1323 1324 spin_lock(&mdsc->snapid_map_lock);1325 while ((p = rb_first(&mdsc->snapid_map_tree))) {1326 sm = rb_entry(p, struct ceph_snapid_map, node);1327 rb_erase(p, &mdsc->snapid_map_tree);1328 RB_CLEAR_NODE(p);1329 list_move(&sm->lru, &to_free);1330 }1331 spin_unlock(&mdsc->snapid_map_lock);1332 1333 while (!list_empty(&to_free)) {1334 sm = list_first_entry(&to_free, struct ceph_snapid_map, lru);1335 list_del(&sm->lru);1336 free_anon_bdev(sm->dev);1337 if (WARN_ON_ONCE(atomic_read(&sm->ref))) {1338 pr_err_client(cl, "snapid map %llx -> %x still in use\n",1339 sm->snap, sm->dev);1340 }1341 kfree(sm);1342 }1343}1344