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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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#include <linux/fs.h>#include <linux/sort.h>#include <linux/slab.h>#include <linux/iversion.h>#include "super.h"#include "mds_client.h"#include <linux/ceph/decode.h>
/* unused map expires after 5 minutes */#define CEPH_SNAPID_MAP_TIMEOUT (5 * 60 * HZ)
/* * Snapshots in ceph are driven in large part by cooperation from the * client. In contrast to local file systems or file servers that * implement snapshots at a single point in the system, ceph's * distributed access to storage requires clients to help decide * whether a write logically occurs before or after a recently created * snapshot. * * This provides a perfect instantanous client-wide snapshot. Between * clients, however, snapshots may appear to be applied at slightly * different points in time, depending on delays in delivering the * snapshot notification. * * Snapshots are _not_ file system-wide. Instead, each snapshot * applies to the subdirectory nested beneath some directory. This * effectively divides the hierarchy into multiple "realms," where all * of the files contained by each realm share the same set of * snapshots. An individual realm's snap set contains snapshots * explicitly created on that realm, as well as any snaps in its * parent's snap set _after_ the point at which the parent became it's * parent (due to, say, a rename). Similarly, snaps from prior parents * during the time intervals during which they were the parent are included. * * The client is spared most of this detail, fortunately... it must only * maintains a hierarchy of realms reflecting the current parent/child * realm relationship, and for each realm has an explicit list of snaps * inherited from prior parents. * * A snap_realm struct is maintained for realms containing every inode * with an open cap in the system. (The needed snap realm information is * provided by the MDS whenever a cap is issued, i.e., on open.) A 'seq' * version number is used to ensure that as realm parameters change (new * snapshot, new parent, etc.) the client's realm hierarchy is updated. * * The realm hierarchy drives the generation of a 'snap context' for each * realm, which simply lists the resulting set of snaps for the realm. This * is attached to any writes sent to OSDs. *//* * Unfortunately error handling is a bit mixed here. If we get a snap * update, but don't have enough memory to update our realm hierarchy, * it's not clear what we can do about it (besides complaining to the * console). */
/* * increase ref count for the realm * * caller must hold snap_rwsem. */void ceph_get_snap_realm(struct ceph_mds_client *mdsc, struct ceph_snap_realm *realm){ lockdep_assert_held(&mdsc->snap_rwsem);
/* * The 0->1 and 1->0 transitions must take the snap_empty_lock * atomically with the refcount change. Go ahead and bump the * nref here, unless it's 0, in which case we take the spinlock * and then do the increment and remove it from the list. */ if (atomic_inc_not_zero(&realm->nref)) return;
spin_lock(&mdsc->snap_empty_lock); if (atomic_inc_return(&realm->nref) == 1) list_del_init(&realm->empty_item); spin_unlock(&mdsc->snap_empty_lock);}
static void __insert_snap_realm(struct rb_root *root, struct ceph_snap_realm *new){ struct rb_node **p = &root->rb_node; struct rb_node *parent = NULL; struct ceph_snap_realm *r = NULL;
while (*p) { parent = *p; r = rb_entry(parent, struct ceph_snap_realm, node); if (new->ino < r->ino) p = &(*p)->rb_left; else if (new->ino > r->ino) p = &(*p)->rb_right; else BUG(); }
rb_link_node(&new->node, parent, p); rb_insert_color(&new->node, root);}
/* * create and get the realm rooted at @ino and bump its ref count. * * caller must hold snap_rwsem for write. */static struct ceph_snap_realm *ceph_create_snap_realm( struct ceph_mds_client *mdsc, u64 ino){ struct ceph_snap_realm *realm;
lockdep_assert_held_write(&mdsc->snap_rwsem);
realm = kzalloc_obj(*realm, GFP_NOFS); if (!realm) return ERR_PTR(-ENOMEM);
/* Do not release the global dummy snaprealm until unmouting */ if (ino == CEPH_INO_GLOBAL_SNAPREALM) atomic_set(&realm->nref, 2); else atomic_set(&realm->nref, 1); realm->ino = ino; INIT_LIST_HEAD(&realm->children); INIT_LIST_HEAD(&realm->child_item); INIT_LIST_HEAD(&realm->empty_item); INIT_LIST_HEAD(&realm->dirty_item); INIT_LIST_HEAD(&realm->rebuild_item); INIT_LIST_HEAD(&realm->inodes_with_caps); spin_lock_init(&realm->inodes_with_caps_lock); __insert_snap_realm(&mdsc->snap_realms, realm); mdsc->num_snap_realms++;
doutc(mdsc->fsc->client, "%llx %p\n", realm->ino, realm); return realm;}
/* * lookup the realm rooted at @ino. * * caller must hold snap_rwsem. */static struct ceph_snap_realm *__lookup_snap_realm(struct ceph_mds_client *mdsc, u64 ino){ struct ceph_client *cl = mdsc->fsc->client; struct rb_node *n = mdsc->snap_realms.rb_node; struct ceph_snap_realm *r;
lockdep_assert_held(&mdsc->snap_rwsem);
while (n) { r = rb_entry(n, struct ceph_snap_realm, node); if (ino < r->ino) n = n->rb_left; else if (ino > r->ino) n = n->rb_right; else { doutc(cl, "%llx %p\n", r->ino, r); return r; } } return NULL;}
struct ceph_snap_realm *ceph_lookup_snap_realm(struct ceph_mds_client *mdsc, u64 ino){ struct ceph_snap_realm *r; r = __lookup_snap_realm(mdsc, ino); if (r) ceph_get_snap_realm(mdsc, r); return r;}
static void __put_snap_realm(struct ceph_mds_client *mdsc, struct ceph_snap_realm *realm);
/* * called with snap_rwsem (write) */static void __destroy_snap_realm(struct ceph_mds_client *mdsc, struct ceph_snap_realm *realm){ struct ceph_client *cl = mdsc->fsc->client; lockdep_assert_held_write(&mdsc->snap_rwsem);
doutc(cl, "%p %llx\n", realm, realm->ino);
rb_erase(&realm->node, &mdsc->snap_realms); mdsc->num_snap_realms--;
if (realm->parent) { list_del_init(&realm->child_item); __put_snap_realm(mdsc, realm->parent); }
kfree(realm->prior_parent_snaps); kfree(realm->snaps); ceph_put_snap_context(realm->cached_context); kfree(realm);}
/* * caller holds snap_rwsem (write) */static void __put_snap_realm(struct ceph_mds_client *mdsc, struct ceph_snap_realm *realm){ lockdep_assert_held_write(&mdsc->snap_rwsem);
/* * We do not require the snap_empty_lock here, as any caller that * increments the value must hold the snap_rwsem. */ if (atomic_dec_and_test(&realm->nref)) __destroy_snap_realm(mdsc, realm);}
/* * See comments in ceph_get_snap_realm. Caller needn't hold any locks. */void ceph_put_snap_realm(struct ceph_mds_client *mdsc, struct ceph_snap_realm *realm){ if (!atomic_dec_and_lock(&realm->nref, &mdsc->snap_empty_lock)) return;
if (down_write_trylock(&mdsc->snap_rwsem)) { spin_unlock(&mdsc->snap_empty_lock); __destroy_snap_realm(mdsc, realm); up_write(&mdsc->snap_rwsem); } else { list_add(&realm->empty_item, &mdsc->snap_empty); spin_unlock(&mdsc->snap_empty_lock); }}
/* * Clean up any realms whose ref counts have dropped to zero. Note * that this does not include realms who were created but not yet * used. * * Called under snap_rwsem (write) */static void __cleanup_empty_realms(struct ceph_mds_client *mdsc){ struct ceph_snap_realm *realm;
lockdep_assert_held_write(&mdsc->snap_rwsem);
spin_lock(&mdsc->snap_empty_lock); while (!list_empty(&mdsc->snap_empty)) { realm = list_first_entry(&mdsc->snap_empty, struct ceph_snap_realm, empty_item); list_del(&realm->empty_item); spin_unlock(&mdsc->snap_empty_lock); __destroy_snap_realm(mdsc, realm); spin_lock(&mdsc->snap_empty_lock); } spin_unlock(&mdsc->snap_empty_lock);}
void ceph_cleanup_global_and_empty_realms(struct ceph_mds_client *mdsc){ struct ceph_snap_realm *global_realm;
down_write(&mdsc->snap_rwsem); global_realm = __lookup_snap_realm(mdsc, CEPH_INO_GLOBAL_SNAPREALM); if (global_realm) ceph_put_snap_realm(mdsc, global_realm); __cleanup_empty_realms(mdsc); up_write(&mdsc->snap_rwsem);}
/* * adjust the parent realm of a given @realm. adjust child list, and parent * pointers, and ref counts appropriately. * * return true if parent was changed, 0 if unchanged, <0 on error. * * caller must hold snap_rwsem for write. */static int adjust_snap_realm_parent(struct ceph_mds_client *mdsc, struct ceph_snap_realm *realm, u64 parentino){ struct ceph_client *cl = mdsc->fsc->client; struct ceph_snap_realm *parent;
lockdep_assert_held_write(&mdsc->snap_rwsem);
if (realm->parent_ino == parentino) return 0;
parent = ceph_lookup_snap_realm(mdsc, parentino); if (!parent) { parent = ceph_create_snap_realm(mdsc, parentino); if (IS_ERR(parent)) return PTR_ERR(parent); } doutc(cl, "%llx %p: %llx %p -> %llx %p\n", realm->ino, realm, realm->parent_ino, realm->parent, parentino, parent); if (realm->parent) { list_del_init(&realm->child_item); ceph_put_snap_realm(mdsc, realm->parent); } realm->parent_ino = parentino; realm->parent = parent; list_add(&realm->child_item, &parent->children); return 1;}
static int cmpu64_rev(const void *a, const void *b){ if (*(u64 *)a < *(u64 *)b) return 1; if (*(u64 *)a > *(u64 *)b) return -1; return 0;}
/* * build the snap context for a given realm. */static int build_snap_context(struct ceph_mds_client *mdsc, struct ceph_snap_realm *realm, struct list_head *realm_queue, struct list_head *dirty_realms){ struct ceph_client *cl = mdsc->fsc->client; struct ceph_snap_realm *parent = realm->parent; struct ceph_snap_context *snapc; int err = 0; u32 num = realm->num_prior_parent_snaps + realm->num_snaps;
/* * build parent context, if it hasn't been built. * conservatively estimate that all parent snaps might be * included by us. */ if (parent) { if (!parent->cached_context) { /* add to the queue head */ list_add(&parent->rebuild_item, realm_queue); return 1; } num += parent->cached_context->num_snaps; }
/* do i actually need to update? not if my context seq matches realm seq, and my parents' does to. (this works because we rebuild_snap_realms() works _downward_ in hierarchy after each update.) */ if (realm->cached_context && realm->cached_context->seq == realm->seq && (!parent || realm->cached_context->seq >= parent->cached_context->seq)) { doutc(cl, "%llx %p: %p seq %lld (%u snaps) (unchanged)\n", realm->ino, realm, realm->cached_context, realm->cached_context->seq, (unsigned int)realm->cached_context->num_snaps); return 0; }
/* alloc new snap context */ err = -ENOMEM; if ((size_t)num > (SIZE_MAX - sizeof(*snapc)) / sizeof(u64)) goto fail; snapc = ceph_create_snap_context(num, GFP_NOFS); if (!snapc) goto fail;
/* build (reverse sorted) snap vector */ num = 0; snapc->seq = realm->seq; if (parent) { u32 i;
/* include any of parent's snaps occurring _after_ my parent became my parent */ for (i = 0; i < parent->cached_context->num_snaps; i++) if (parent->cached_context->snaps[i] >= realm->parent_since) snapc->snaps[num++] = parent->cached_context->snaps[i]; if (parent->cached_context->seq > snapc->seq) snapc->seq = parent->cached_context->seq; } memcpy(snapc->snaps + num, realm->snaps, sizeof(u64)*realm->num_snaps); num += realm->num_snaps; memcpy(snapc->snaps + num, realm->prior_parent_snaps, sizeof(u64)*realm->num_prior_parent_snaps); num += realm->num_prior_parent_snaps;
sort(snapc->snaps, num, sizeof(u64), cmpu64_rev, NULL); snapc->num_snaps = num; doutc(cl, "%llx %p: %p seq %lld (%u snaps)\n", realm->ino, realm, snapc, snapc->seq, (unsigned int) snapc->num_snaps);
ceph_put_snap_context(realm->cached_context); realm->cached_context = snapc; /* queue realm for cap_snap creation */ list_add_tail(&realm->dirty_item, dirty_realms); return 0;
fail: /* * if we fail, clear old (incorrect) cached_context... hopefully * we'll have better luck building it later */ if (realm->cached_context) { ceph_put_snap_context(realm->cached_context); realm->cached_context = NULL; } pr_err_client(cl, "%llx %p fail %d\n", realm->ino, realm, err); return err;}
/* * rebuild snap context for the given realm and all of its children. */static void rebuild_snap_realms(struct ceph_mds_client *mdsc, struct ceph_snap_realm *realm, struct list_head *dirty_realms){ struct ceph_client *cl = mdsc->fsc->client; LIST_HEAD(realm_queue); int last = 0; bool skip = false;
list_add_tail(&realm->rebuild_item, &realm_queue);
while (!list_empty(&realm_queue)) { struct ceph_snap_realm *_realm, *child;
_realm = list_first_entry(&realm_queue, struct ceph_snap_realm, rebuild_item);
/* * If the last building failed dues to memory * issue, just empty the realm_queue and return * to avoid infinite loop. */ if (last < 0) { list_del_init(&_realm->rebuild_item); continue; }
last = build_snap_context(mdsc, _realm, &realm_queue, dirty_realms); doutc(cl, "%llx %p, %s\n", realm->ino, realm, last > 0 ? "is deferred" : !last ? "succeeded" : "failed");
/* is any child in the list ? */ list_for_each_entry(child, &_realm->children, child_item) { if (!list_empty(&child->rebuild_item)) { skip = true; break; } }
if (!skip) { list_for_each_entry(child, &_realm->children, child_item) list_add_tail(&child->rebuild_item, &realm_queue); }
/* last == 1 means need to build parent first */ if (last <= 0) list_del_init(&_realm->rebuild_item); }}
/* * helper to allocate and decode an array of snapids. free prior * instance, if any. */static int dup_array(u64 **dst, __le64 *src, u32 num){ u32 i;
kfree(*dst); if (num) { *dst = kcalloc(num, sizeof(u64), GFP_NOFS); if (!*dst) return -ENOMEM; for (i = 0; i < num; i++) (*dst)[i] = get_unaligned_le64(src + i); } else { *dst = NULL; } return 0;}
static bool has_new_snaps(struct ceph_snap_context *o, struct ceph_snap_context *n){ if (n->num_snaps == 0) return false; /* snaps are in descending order */ return n->snaps[0] > o->seq;}
/* * When a snapshot is applied, the size/mtime inode metadata is queued * in a ceph_cap_snap (one for each snapshot) until writeback * completes and the metadata can be flushed back to the MDS. * * However, if a (sync) write is currently in-progress when we apply * the snapshot, we have to wait until the write succeeds or fails * (and a final size/mtime is known). In this case the * cap_snap->writing = 1, and is said to be "pending." When the write * finishes, we __ceph_finish_cap_snap(). * * Caller must hold snap_rwsem for read (i.e., the realm topology won't * change). */static void ceph_queue_cap_snap(struct ceph_inode_info *ci, struct ceph_cap_snap **pcapsnap){ struct inode *inode = &ci->netfs.inode; struct ceph_client *cl = ceph_inode_to_client(inode); struct ceph_snap_context *old_snapc, *new_snapc; struct ceph_cap_snap *capsnap = *pcapsnap; struct ceph_buffer *old_blob = NULL; int used, dirty;
spin_lock(&ci->i_ceph_lock); used = __ceph_caps_used(ci); dirty = __ceph_caps_dirty(ci);
old_snapc = ci->i_head_snapc; new_snapc = ci->i_snap_realm->cached_context;
/* * If there is a write in progress, treat that as a dirty Fw, * even though it hasn't completed yet; by the time we finish * up this capsnap it will be. */ if (used & CEPH_CAP_FILE_WR) dirty |= CEPH_CAP_FILE_WR;
if (__ceph_have_pending_cap_snap(ci)) { /* there is no point in queuing multiple "pending" cap_snaps, as no new writes are allowed to start when pending, so any writes in progress now were started before the previous cap_snap. lucky us. */ doutc(cl, "%p %llx.%llx already pending\n", inode, ceph_vinop(inode)); goto update_snapc; } if (ci->i_wrbuffer_ref_head == 0 && !(dirty & (CEPH_CAP_ANY_EXCL|CEPH_CAP_FILE_WR))) { doutc(cl, "%p %llx.%llx nothing dirty|writing\n", inode, ceph_vinop(inode)); goto update_snapc; }
BUG_ON(!old_snapc);
/* * There is no need to send FLUSHSNAP message to MDS if there is * no new snapshot. But when there is dirty pages or on-going * writes, we still need to create cap_snap. cap_snap is needed * by the write path and page writeback path. * * also see ceph_try_drop_cap_snap() */ if (has_new_snaps(old_snapc, new_snapc)) { if (dirty & (CEPH_CAP_ANY_EXCL|CEPH_CAP_FILE_WR)) capsnap->need_flush = true; } else { if (!(used & CEPH_CAP_FILE_WR) && ci->i_wrbuffer_ref_head == 0) { doutc(cl, "%p %llx.%llx no new_snap|dirty_page|writing\n", inode, ceph_vinop(inode)); goto update_snapc; } }
doutc(cl, "%p %llx.%llx cap_snap %p queuing under %p %s %s\n", inode, ceph_vinop(inode), capsnap, old_snapc, ceph_cap_string(dirty), capsnap->need_flush ? "" : "no_flush"); ihold(inode);
capsnap->follows = old_snapc->seq; capsnap->issued = __ceph_caps_issued(ci, NULL); capsnap->dirty = dirty;
capsnap->mode = inode->i_mode; capsnap->uid = inode->i_uid; capsnap->gid = inode->i_gid;
if (dirty & CEPH_CAP_XATTR_EXCL) { old_blob = __ceph_build_xattrs_blob(ci); capsnap->xattr_blob = ceph_buffer_get(ci->i_xattrs.blob); capsnap->xattr_version = ci->i_xattrs.version; } else { capsnap->xattr_blob = NULL; capsnap->xattr_version = 0; }
capsnap->inline_data = ci->i_inline_version != CEPH_INLINE_NONE;
/* dirty page count moved from _head to this cap_snap; all subsequent writes page dirties occur _after_ this snapshot. */ capsnap->dirty_pages = ci->i_wrbuffer_ref_head; ci->i_wrbuffer_ref_head = 0; capsnap->context = old_snapc; list_add_tail(&capsnap->ci_item, &ci->i_cap_snaps);
if (used & CEPH_CAP_FILE_WR) { doutc(cl, "%p %llx.%llx cap_snap %p snapc %p seq %llu used WR," " now pending\n", inode, ceph_vinop(inode), capsnap, old_snapc, old_snapc->seq); capsnap->writing = 1; } else { /* note mtime, size NOW. */ __ceph_finish_cap_snap(ci, capsnap); } *pcapsnap = NULL; old_snapc = NULL;
update_snapc: if (ci->i_wrbuffer_ref_head == 0 && ci->i_wr_ref == 0 && ci->i_dirty_caps == 0 && ci->i_flushing_caps == 0) { ci->i_head_snapc = NULL; } else { ci->i_head_snapc = ceph_get_snap_context(new_snapc); doutc(cl, " new snapc is %p\n", new_snapc); } spin_unlock(&ci->i_ceph_lock);
ceph_buffer_put(old_blob); ceph_put_snap_context(old_snapc);}
/* * Finalize the size, mtime for a cap_snap.. that is, settle on final values * to be used for the snapshot, to be flushed back to the mds. * * If capsnap can now be flushed, add to snap_flush list, and return 1. * * Caller must hold i_ceph_lock. */int __ceph_finish_cap_snap(struct ceph_inode_info *ci, struct ceph_cap_snap *capsnap){ struct inode *inode = &ci->netfs.inode; struct ceph_mds_client *mdsc = ceph_sb_to_mdsc(inode->i_sb); struct ceph_client *cl = mdsc->fsc->client;
BUG_ON(capsnap->writing); capsnap->size = i_size_read(inode); capsnap->mtime = inode_get_mtime(inode); capsnap->atime = inode_get_atime(inode); capsnap->ctime = inode_get_ctime(inode); capsnap->btime = ci->i_btime; capsnap->change_attr = inode_peek_iversion_raw(inode); capsnap->time_warp_seq = ci->i_time_warp_seq; capsnap->truncate_size = ci->i_truncate_size; capsnap->truncate_seq = ci->i_truncate_seq; if (capsnap->dirty_pages) { doutc(cl, "%p %llx.%llx cap_snap %p snapc %p %llu %s " "s=%llu still has %d dirty pages\n", inode, ceph_vinop(inode), capsnap, capsnap->context, capsnap->context->seq, ceph_cap_string(capsnap->dirty), capsnap->size, capsnap->dirty_pages); return 0; }
/* * Defer flushing the capsnap if the dirty buffer not flushed yet. * And trigger to flush the buffer immediately. */ if (ci->i_wrbuffer_ref) { doutc(cl, "%p %llx.%llx cap_snap %p snapc %p %llu %s " "s=%llu used WRBUFFER, delaying\n", inode, ceph_vinop(inode), capsnap, capsnap->context, capsnap->context->seq, ceph_cap_string(capsnap->dirty), capsnap->size); ceph_queue_writeback(inode); return 0; }
set_bit(CEPH_I_FLUSH_SNAPS_BIT, &ci->i_ceph_flags); doutc(cl, "%p %llx.%llx cap_snap %p snapc %p %llu %s s=%llu\n", inode, ceph_vinop(inode), capsnap, capsnap->context, capsnap->context->seq, ceph_cap_string(capsnap->dirty), capsnap->size);
spin_lock(&mdsc->snap_flush_lock); if (list_empty(&ci->i_snap_flush_item)) { ihold(inode); list_add_tail(&ci->i_snap_flush_item, &mdsc->snap_flush_list); } spin_unlock(&mdsc->snap_flush_lock); return 1; /* caller may want to ceph_flush_snaps */}
/* * Queue cap_snaps for snap writeback for this realm and its children. * Called under snap_rwsem, so realm topology won't change. */static void queue_realm_cap_snaps(struct ceph_mds_client *mdsc, struct ceph_snap_realm *realm){ struct ceph_client *cl = mdsc->fsc->client; struct ceph_inode_info *ci; struct inode *lastinode = NULL; struct ceph_cap_snap *capsnap = NULL;
doutc(cl, "%p %llx inode\n", realm, realm->ino);
spin_lock(&realm->inodes_with_caps_lock); list_for_each_entry(ci, &realm->inodes_with_caps, i_snap_realm_item) { struct inode *inode = igrab(&ci->netfs.inode); if (!inode) continue; spin_unlock(&realm->inodes_with_caps_lock); iput(lastinode); lastinode = inode;
/* * Allocate the capsnap memory outside of ceph_queue_cap_snap() * to reduce very possible but unnecessary frequently memory * allocate/free in this loop. */ if (!capsnap) { capsnap = kmem_cache_zalloc(ceph_cap_snap_cachep, GFP_NOFS); if (!capsnap) { pr_err_client(cl, "ENOMEM allocating ceph_cap_snap on %p\n", inode); return; } } capsnap->cap_flush.is_capsnap = true; refcount_set(&capsnap->nref, 1); INIT_LIST_HEAD(&capsnap->cap_flush.i_list); INIT_LIST_HEAD(&capsnap->cap_flush.g_list); INIT_LIST_HEAD(&capsnap->ci_item);
ceph_queue_cap_snap(ci, &capsnap); spin_lock(&realm->inodes_with_caps_lock); } spin_unlock(&realm->inodes_with_caps_lock); iput(lastinode);
if (capsnap) kmem_cache_free(ceph_cap_snap_cachep, capsnap); doutc(cl, "%p %llx done\n", realm, realm->ino);}
/* * Parse and apply a snapblob "snap trace" from the MDS. This specifies * the snap realm parameters from a given realm and all of its ancestors, * up to the root. * * Caller must hold snap_rwsem for write. */int ceph_update_snap_trace(struct ceph_mds_client *mdsc, void *p, void *e, bool deletion, struct ceph_snap_realm **realm_ret){ struct ceph_client *cl = mdsc->fsc->client; struct ceph_mds_snap_realm *ri; /* encoded */ __le64 *snaps; /* encoded */ __le64 *prior_parent_snaps; /* encoded */ struct ceph_snap_realm *realm; struct ceph_snap_realm *first_realm = NULL; struct ceph_snap_realm *realm_to_rebuild = NULL; struct ceph_client *client = mdsc->fsc->client; int rebuild_snapcs; int err = -ENOMEM; int ret; LIST_HEAD(dirty_realms);
lockdep_assert_held_write(&mdsc->snap_rwsem);
doutc(cl, "deletion=%d\n", deletion);more: realm = NULL; rebuild_snapcs = 0; ceph_decode_need(&p, e, sizeof(*ri), bad); ri = p; p += sizeof(*ri); ceph_decode_need(&p, e, sizeof(u64)*(le32_to_cpu(ri->num_snaps) + le32_to_cpu(ri->num_prior_parent_snaps)), bad); snaps = p; p += sizeof(u64) * le32_to_cpu(ri->num_snaps); prior_parent_snaps = p; p += sizeof(u64) * le32_to_cpu(ri->num_prior_parent_snaps);
realm = ceph_lookup_snap_realm(mdsc, le64_to_cpu(ri->ino)); if (!realm) { realm = ceph_create_snap_realm(mdsc, le64_to_cpu(ri->ino)); if (IS_ERR(realm)) { err = PTR_ERR(realm); goto fail; } }
/* ensure the parent is correct */ err = adjust_snap_realm_parent(mdsc, realm, le64_to_cpu(ri->parent)); if (err < 0) goto fail; rebuild_snapcs += err;
if (le64_to_cpu(ri->seq) > realm->seq) { doutc(cl, "updating %llx %p %lld -> %lld\n", realm->ino, realm, realm->seq, le64_to_cpu(ri->seq)); /* update realm parameters, snap lists */ realm->seq = le64_to_cpu(ri->seq); realm->created = le64_to_cpu(ri->created); realm->parent_since = le64_to_cpu(ri->parent_since);
realm->num_snaps = le32_to_cpu(ri->num_snaps); err = dup_array(&realm->snaps, snaps, realm->num_snaps); if (err < 0) goto fail;
realm->num_prior_parent_snaps = le32_to_cpu(ri->num_prior_parent_snaps); err = dup_array(&realm->prior_parent_snaps, prior_parent_snaps, realm->num_prior_parent_snaps); if (err < 0) goto fail;
if (realm->seq > mdsc->last_snap_seq) mdsc->last_snap_seq = realm->seq;
rebuild_snapcs = 1; } else if (!realm->cached_context) { doutc(cl, "%llx %p seq %lld new\n", realm->ino, realm, realm->seq); rebuild_snapcs = 1; } else { doutc(cl, "%llx %p seq %lld unchanged\n", realm->ino, realm, realm->seq); }
doutc(cl, "done with %llx %p, rebuild_snapcs=%d, %p %p\n", realm->ino, realm, rebuild_snapcs, p, e);
/* * this will always track the uppest parent realm from which * we need to rebuild the snapshot contexts _downward_ in * hierarchy. */ if (rebuild_snapcs) realm_to_rebuild = realm;
/* rebuild_snapcs when we reach the _end_ (root) of the trace */ if (realm_to_rebuild && p >= e) rebuild_snap_realms(mdsc, realm_to_rebuild, &dirty_realms);
if (!first_realm) first_realm = realm; else ceph_put_snap_realm(mdsc, realm);
if (p < e) goto more;
/* * queue cap snaps _after_ we've built the new snap contexts, * so that i_head_snapc can be set appropriately. */ while (!list_empty(&dirty_realms)) { realm = list_first_entry(&dirty_realms, struct ceph_snap_realm, dirty_item); list_del_init(&realm->dirty_item); queue_realm_cap_snaps(mdsc, realm); }
if (realm_ret) *realm_ret = first_realm; else ceph_put_snap_realm(mdsc, first_realm);
__cleanup_empty_realms(mdsc); return 0;
bad: err = -EIO;fail: if (realm && !IS_ERR(realm)) ceph_put_snap_realm(mdsc, realm); if (first_realm) ceph_put_snap_realm(mdsc, first_realm); pr_err_client(cl, "error %d\n", err);
/* * When receiving a corrupted snap trace we don't know what * exactly has happened in MDS side. And we shouldn't continue * writing to OSD, which may corrupt the snapshot contents. * * Just try to blocklist this kclient and then this kclient * must be remounted to continue after the corrupted metadata * fixed in the MDS side. */ WRITE_ONCE(mdsc->fsc->mount_state, CEPH_MOUNT_FENCE_IO); ret = ceph_monc_blocklist_add(&client->monc, &client->msgr.inst.addr); if (ret) pr_err_client(cl, "failed to blocklist %s: %d\n", ceph_pr_addr(&client->msgr.inst.addr), ret);
WARN(1, "[client.%lld] %s %s%sdo remount to continue%s", client->monc.auth->global_id, __func__, ret ? "" : ceph_pr_addr(&client->msgr.inst.addr), ret ? "" : " was blocklisted, ", err == -EIO ? " after corrupted snaptrace is fixed" : "");
return err;}
/* * Send any cap_snaps that are queued for flush. Try to carry * s_mutex across multiple snap flushes to avoid locking overhead. * * Caller holds no locks. */static void flush_snaps(struct ceph_mds_client *mdsc){ struct ceph_client *cl = mdsc->fsc->client; struct ceph_inode_info *ci; struct inode *inode; struct ceph_mds_session *session = NULL;
doutc(cl, "begin\n"); spin_lock(&mdsc->snap_flush_lock); while (!list_empty(&mdsc->snap_flush_list)) { ci = list_first_entry(&mdsc->snap_flush_list, struct ceph_inode_info, i_snap_flush_item); inode = &ci->netfs.inode; ihold(inode); spin_unlock(&mdsc->snap_flush_lock); ceph_flush_snaps(ci, &session); iput(inode); spin_lock(&mdsc->snap_flush_lock); } spin_unlock(&mdsc->snap_flush_lock);
ceph_put_mds_session(session); doutc(cl, "done\n");}
/** * ceph_change_snap_realm - change the snap_realm for an inode * @inode: inode to move to new snap realm * @realm: new realm to move inode into (may be NULL) * * Detach an inode from its old snaprealm (if any) and attach it to * the new snaprealm (if any). The old snap realm reference held by * the inode is put. If realm is non-NULL, then the caller's reference * to it is taken over by the inode. */void ceph_change_snap_realm(struct inode *inode, struct ceph_snap_realm *realm){ struct ceph_inode_info *ci = ceph_inode(inode); struct ceph_mds_client *mdsc = ceph_inode_to_fs_client(inode)->mdsc; struct ceph_snap_realm *oldrealm = ci->i_snap_realm;
lockdep_assert_held(&ci->i_ceph_lock);
if (oldrealm) { spin_lock(&oldrealm->inodes_with_caps_lock); list_del_init(&ci->i_snap_realm_item); if (oldrealm->ino == ci->i_vino.ino) oldrealm->inode = NULL; spin_unlock(&oldrealm->inodes_with_caps_lock); ceph_put_snap_realm(mdsc, oldrealm); }
ci->i_snap_realm = realm;
if (realm) { spin_lock(&realm->inodes_with_caps_lock); list_add(&ci->i_snap_realm_item, &realm->inodes_with_caps); if (realm->ino == ci->i_vino.ino) realm->inode = inode; spin_unlock(&realm->inodes_with_caps_lock); }}
/* * Handle a snap notification from the MDS. * * This can take two basic forms: the simplest is just a snap creation * or deletion notification on an existing realm. This should update the * realm and its children. * * The more difficult case is realm creation, due to snap creation at a * new point in the file hierarchy, or due to a rename that moves a file or * directory into another realm. */void ceph_handle_snap(struct ceph_mds_client *mdsc, struct ceph_mds_session *session, struct ceph_msg *msg){ struct ceph_client *cl = mdsc->fsc->client; struct super_block *sb = mdsc->fsc->sb; int mds = session->s_mds; u64 split; int op; int trace_len; struct ceph_snap_realm *realm = NULL; void *p = msg->front.iov_base; void *e = p + msg->front.iov_len; struct ceph_mds_snap_head *h; int num_split_inos, num_split_realms; __le64 *split_inos = NULL, *split_realms = NULL; int i; int locked_rwsem = 0; bool close_sessions = false;
if (!ceph_inc_mds_stopping_blocker(mdsc, session)) return;
/* decode */ if (msg->front.iov_len < sizeof(*h)) goto bad; h = p; op = le32_to_cpu(h->op); split = le64_to_cpu(h->split); /* non-zero if we are splitting an * existing realm */ num_split_inos = le32_to_cpu(h->num_split_inos); num_split_realms = le32_to_cpu(h->num_split_realms); trace_len = le32_to_cpu(h->trace_len); p += sizeof(*h);
doutc(cl, "from mds%d op %s split %llx tracelen %d\n", mds, ceph_snap_op_name(op), split, trace_len);
down_write(&mdsc->snap_rwsem); locked_rwsem = 1;
if (op == CEPH_SNAP_OP_SPLIT) { struct ceph_mds_snap_realm *ri;
/* * A "split" breaks part of an existing realm off into * a new realm. The MDS provides a list of inodes * (with caps) and child realms that belong to the new * child. */ split_inos = p; p += sizeof(u64) * num_split_inos; split_realms = p; p += sizeof(u64) * num_split_realms; ceph_decode_need(&p, e, sizeof(*ri), bad); /* we will peek at realm info here, but will _not_ * advance p, as the realm update will occur below in * ceph_update_snap_trace. */ ri = p;
realm = ceph_lookup_snap_realm(mdsc, split); if (!realm) { realm = ceph_create_snap_realm(mdsc, split); if (IS_ERR(realm)) goto out; }
doutc(cl, "splitting snap_realm %llx %p\n", realm->ino, realm); for (i = 0; i < num_split_inos; i++) { struct ceph_vino vino = { .ino = le64_to_cpu(split_inos[i]), .snap = CEPH_NOSNAP, }; struct inode *inode = ceph_find_inode(sb, vino); struct ceph_inode_info *ci;
if (!inode) continue; ci = ceph_inode(inode);
spin_lock(&ci->i_ceph_lock); if (!ci->i_snap_realm) goto skip_inode; /* * If this inode belongs to a realm that was * created after our new realm, we experienced * a race (due to another split notifications * arriving from a different MDS). So skip * this inode. */ if (ci->i_snap_realm->created > le64_to_cpu(ri->created)) { doutc(cl, " leaving %p %llx.%llx in newer realm %llx %p\n", inode, ceph_vinop(inode), ci->i_snap_realm->ino, ci->i_snap_realm); goto skip_inode; } doutc(cl, " will move %p %llx.%llx to split realm %llx %p\n", inode, ceph_vinop(inode), realm->ino, realm);
ceph_get_snap_realm(mdsc, realm); ceph_change_snap_realm(inode, realm); spin_unlock(&ci->i_ceph_lock); iput(inode); continue;
skip_inode: spin_unlock(&ci->i_ceph_lock); iput(inode); }
/* we may have taken some of the old realm's children. */ for (i = 0; i < num_split_realms; i++) { struct ceph_snap_realm *child = __lookup_snap_realm(mdsc, le64_to_cpu(split_realms[i])); if (!child) continue; adjust_snap_realm_parent(mdsc, child, realm->ino); } } else { /* * In the non-split case both 'num_split_inos' and * 'num_split_realms' should be 0, making this a no-op. * However the MDS happens to populate 'split_realms' list * in one of the UPDATE op cases by mistake. * * Skip both lists just in case to ensure that 'p' is * positioned at the start of realm info, as expected by * ceph_update_snap_trace(). */ p += sizeof(u64) * num_split_inos; p += sizeof(u64) * num_split_realms; }
/* * update using the provided snap trace. if we are deleting a * snap, we can avoid queueing cap_snaps. */ if (ceph_update_snap_trace(mdsc, p, e, op == CEPH_SNAP_OP_DESTROY, NULL)) { close_sessions = true; goto bad; }
if (op == CEPH_SNAP_OP_SPLIT) /* we took a reference when we created the realm, above */ ceph_put_snap_realm(mdsc, realm);
__cleanup_empty_realms(mdsc);
up_write(&mdsc->snap_rwsem);
flush_snaps(mdsc); ceph_dec_mds_stopping_blocker(mdsc); return;
bad: pr_err_client(cl, "corrupt snap message from mds%d\n", mds); ceph_msg_dump(msg);out: if (locked_rwsem) up_write(&mdsc->snap_rwsem);
ceph_dec_mds_stopping_blocker(mdsc);
if (close_sessions) ceph_mdsc_close_sessions(mdsc); return;}
struct ceph_snapid_map* ceph_get_snapid_map(struct ceph_mds_client *mdsc, u64 snap){ struct ceph_client *cl = mdsc->fsc->client; struct ceph_snapid_map *sm, *exist; struct rb_node **p, *parent; int ret;
exist = NULL; spin_lock(&mdsc->snapid_map_lock); p = &mdsc->snapid_map_tree.rb_node; while (*p) { exist = rb_entry(*p, struct ceph_snapid_map, node); if (snap > exist->snap) { p = &(*p)->rb_left; } else if (snap < exist->snap) { p = &(*p)->rb_right; } else { if (atomic_inc_return(&exist->ref) == 1) list_del_init(&exist->lru); break; } exist = NULL; } spin_unlock(&mdsc->snapid_map_lock); if (exist) { doutc(cl, "found snapid map %llx -> %x\n", exist->snap, exist->dev); return exist; }
sm = kmalloc_obj(*sm, GFP_NOFS); if (!sm) return NULL;
ret = get_anon_bdev(&sm->dev); if (ret < 0) { kfree(sm); return NULL; }
INIT_LIST_HEAD(&sm->lru); atomic_set(&sm->ref, 1); sm->snap = snap;
exist = NULL; parent = NULL; p = &mdsc->snapid_map_tree.rb_node; spin_lock(&mdsc->snapid_map_lock); while (*p) { parent = *p; exist = rb_entry(*p, struct ceph_snapid_map, node); if (snap > exist->snap) p = &(*p)->rb_left; else if (snap < exist->snap) p = &(*p)->rb_right; else break; exist = NULL; } if (exist) { if (atomic_inc_return(&exist->ref) == 1) list_del_init(&exist->lru); } else { rb_link_node(&sm->node, parent, p); rb_insert_color(&sm->node, &mdsc->snapid_map_tree); } spin_unlock(&mdsc->snapid_map_lock); if (exist) { free_anon_bdev(sm->dev); kfree(sm); doutc(cl, "found snapid map %llx -> %x\n", exist->snap, exist->dev); return exist; }
doutc(cl, "create snapid map %llx -> %x\n", sm->snap, sm->dev); return sm;}
void ceph_put_snapid_map(struct ceph_mds_client* mdsc, struct ceph_snapid_map *sm){ if (!sm) return; if (atomic_dec_and_lock(&sm->ref, &mdsc->snapid_map_lock)) { if (!RB_EMPTY_NODE(&sm->node)) { sm->last_used = jiffies; list_add_tail(&sm->lru, &mdsc->snapid_map_lru); spin_unlock(&mdsc->snapid_map_lock); } else { /* already cleaned up by * ceph_cleanup_snapid_map() */ spin_unlock(&mdsc->snapid_map_lock); kfree(sm); } }}
void ceph_trim_snapid_map(struct ceph_mds_client *mdsc){ struct ceph_client *cl = mdsc->fsc->client; struct ceph_snapid_map *sm; unsigned long now; LIST_HEAD(to_free);
spin_lock(&mdsc->snapid_map_lock); now = jiffies;
while (!list_empty(&mdsc->snapid_map_lru)) { sm = list_first_entry(&mdsc->snapid_map_lru, struct ceph_snapid_map, lru); if (time_after(sm->last_used + CEPH_SNAPID_MAP_TIMEOUT, now)) break;
rb_erase(&sm->node, &mdsc->snapid_map_tree); list_move(&sm->lru, &to_free); } spin_unlock(&mdsc->snapid_map_lock);
while (!list_empty(&to_free)) { sm = list_first_entry(&to_free, struct ceph_snapid_map, lru); list_del(&sm->lru); doutc(cl, "trim snapid map %llx -> %x\n", sm->snap, sm->dev); free_anon_bdev(sm->dev); kfree(sm); }}
void ceph_cleanup_snapid_map(struct ceph_mds_client *mdsc){ struct ceph_client *cl = mdsc->fsc->client; struct ceph_snapid_map *sm; struct rb_node *p; LIST_HEAD(to_free);
spin_lock(&mdsc->snapid_map_lock); while ((p = rb_first(&mdsc->snapid_map_tree))) { sm = rb_entry(p, struct ceph_snapid_map, node); rb_erase(p, &mdsc->snapid_map_tree); RB_CLEAR_NODE(p); list_move(&sm->lru, &to_free); } spin_unlock(&mdsc->snapid_map_lock);
while (!list_empty(&to_free)) { sm = list_first_entry(&to_free, struct ceph_snapid_map, lru); list_del(&sm->lru); free_anon_bdev(sm->dev); if (WARN_ON_ONCE(atomic_read(&sm->ref))) { pr_err_client(cl, "snapid map %llx -> %x still in use\n", sm->snap, sm->dev); } kfree(sm); }}