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1177 lines
32 KiB
1177 lines
32 KiB
// SPDX-License-Identifier: GPL-2.0 |
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#include <linux/ceph/ceph_debug.h> |
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|
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#include <linux/sort.h> |
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#include <linux/slab.h> |
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#include <linux/iversion.h> |
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#include "super.h" |
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#include "mds_client.h" |
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#include <linux/ceph/decode.h> |
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|
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/* unused map expires after 5 minutes */ |
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#define CEPH_SNAPID_MAP_TIMEOUT (5 * 60 * HZ) |
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|
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/* |
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* Snapshots in ceph are driven in large part by cooperation from the |
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* client. In contrast to local file systems or file servers that |
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* implement snapshots at a single point in the system, ceph's |
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* distributed access to storage requires clients to help decide |
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* whether a write logically occurs before or after a recently created |
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* snapshot. |
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* |
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* This provides a perfect instantanous client-wide snapshot. Between |
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* clients, however, snapshots may appear to be applied at slightly |
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* different points in time, depending on delays in delivering the |
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* snapshot notification. |
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* |
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* Snapshots are _not_ file system-wide. Instead, each snapshot |
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* applies to the subdirectory nested beneath some directory. This |
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* effectively divides the hierarchy into multiple "realms," where all |
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* of the files contained by each realm share the same set of |
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* snapshots. An individual realm's snap set contains snapshots |
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* explicitly created on that realm, as well as any snaps in its |
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* parent's snap set _after_ the point at which the parent became it's |
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* parent (due to, say, a rename). Similarly, snaps from prior parents |
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* during the time intervals during which they were the parent are included. |
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* |
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* The client is spared most of this detail, fortunately... it must only |
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* maintains a hierarchy of realms reflecting the current parent/child |
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* realm relationship, and for each realm has an explicit list of snaps |
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* inherited from prior parents. |
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* |
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* A snap_realm struct is maintained for realms containing every inode |
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* with an open cap in the system. (The needed snap realm information is |
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* provided by the MDS whenever a cap is issued, i.e., on open.) A 'seq' |
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* version number is used to ensure that as realm parameters change (new |
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* snapshot, new parent, etc.) the client's realm hierarchy is updated. |
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* |
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* The realm hierarchy drives the generation of a 'snap context' for each |
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* realm, which simply lists the resulting set of snaps for the realm. This |
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* is attached to any writes sent to OSDs. |
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*/ |
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/* |
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* Unfortunately error handling is a bit mixed here. If we get a snap |
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* update, but don't have enough memory to update our realm hierarchy, |
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* it's not clear what we can do about it (besides complaining to the |
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* console). |
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*/ |
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/* |
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* increase ref count for the realm |
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* |
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* caller must hold snap_rwsem. |
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*/ |
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void ceph_get_snap_realm(struct ceph_mds_client *mdsc, |
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struct ceph_snap_realm *realm) |
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{ |
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lockdep_assert_held(&mdsc->snap_rwsem); |
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dout("get_realm %p %d -> %d\n", realm, |
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atomic_read(&realm->nref), atomic_read(&realm->nref)+1); |
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/* |
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* since we _only_ increment realm refs or empty the empty |
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* list with snap_rwsem held, adjusting the empty list here is |
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* safe. we do need to protect against concurrent empty list |
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* additions, however. |
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*/ |
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if (atomic_inc_return(&realm->nref) == 1) { |
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spin_lock(&mdsc->snap_empty_lock); |
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list_del_init(&realm->empty_item); |
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spin_unlock(&mdsc->snap_empty_lock); |
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} |
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} |
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static void __insert_snap_realm(struct rb_root *root, |
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struct ceph_snap_realm *new) |
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{ |
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struct rb_node **p = &root->rb_node; |
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struct rb_node *parent = NULL; |
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struct ceph_snap_realm *r = NULL; |
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while (*p) { |
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parent = *p; |
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r = rb_entry(parent, struct ceph_snap_realm, node); |
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if (new->ino < r->ino) |
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p = &(*p)->rb_left; |
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else if (new->ino > r->ino) |
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p = &(*p)->rb_right; |
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else |
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BUG(); |
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} |
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rb_link_node(&new->node, parent, p); |
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rb_insert_color(&new->node, root); |
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} |
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/* |
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* create and get the realm rooted at @ino and bump its ref count. |
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* |
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* caller must hold snap_rwsem for write. |
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*/ |
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static struct ceph_snap_realm *ceph_create_snap_realm( |
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struct ceph_mds_client *mdsc, |
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u64 ino) |
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{ |
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struct ceph_snap_realm *realm; |
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lockdep_assert_held_write(&mdsc->snap_rwsem); |
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realm = kzalloc(sizeof(*realm), GFP_NOFS); |
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if (!realm) |
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return ERR_PTR(-ENOMEM); |
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atomic_set(&realm->nref, 1); /* for caller */ |
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realm->ino = ino; |
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INIT_LIST_HEAD(&realm->children); |
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INIT_LIST_HEAD(&realm->child_item); |
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INIT_LIST_HEAD(&realm->empty_item); |
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INIT_LIST_HEAD(&realm->dirty_item); |
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INIT_LIST_HEAD(&realm->inodes_with_caps); |
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spin_lock_init(&realm->inodes_with_caps_lock); |
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__insert_snap_realm(&mdsc->snap_realms, realm); |
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mdsc->num_snap_realms++; |
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dout("create_snap_realm %llx %p\n", realm->ino, realm); |
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return realm; |
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} |
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/* |
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* lookup the realm rooted at @ino. |
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* |
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* caller must hold snap_rwsem. |
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*/ |
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static struct ceph_snap_realm *__lookup_snap_realm(struct ceph_mds_client *mdsc, |
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u64 ino) |
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{ |
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struct rb_node *n = mdsc->snap_realms.rb_node; |
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struct ceph_snap_realm *r; |
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lockdep_assert_held(&mdsc->snap_rwsem); |
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while (n) { |
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r = rb_entry(n, struct ceph_snap_realm, node); |
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if (ino < r->ino) |
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n = n->rb_left; |
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else if (ino > r->ino) |
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n = n->rb_right; |
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else { |
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dout("lookup_snap_realm %llx %p\n", r->ino, r); |
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return r; |
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} |
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} |
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return NULL; |
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} |
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struct ceph_snap_realm *ceph_lookup_snap_realm(struct ceph_mds_client *mdsc, |
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u64 ino) |
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{ |
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struct ceph_snap_realm *r; |
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r = __lookup_snap_realm(mdsc, ino); |
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if (r) |
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ceph_get_snap_realm(mdsc, r); |
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return r; |
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} |
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static void __put_snap_realm(struct ceph_mds_client *mdsc, |
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struct ceph_snap_realm *realm); |
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/* |
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* called with snap_rwsem (write) |
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*/ |
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static void __destroy_snap_realm(struct ceph_mds_client *mdsc, |
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struct ceph_snap_realm *realm) |
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{ |
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lockdep_assert_held_write(&mdsc->snap_rwsem); |
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dout("__destroy_snap_realm %p %llx\n", realm, realm->ino); |
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rb_erase(&realm->node, &mdsc->snap_realms); |
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mdsc->num_snap_realms--; |
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if (realm->parent) { |
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list_del_init(&realm->child_item); |
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__put_snap_realm(mdsc, realm->parent); |
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} |
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kfree(realm->prior_parent_snaps); |
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kfree(realm->snaps); |
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ceph_put_snap_context(realm->cached_context); |
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kfree(realm); |
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} |
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/* |
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* caller holds snap_rwsem (write) |
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*/ |
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static void __put_snap_realm(struct ceph_mds_client *mdsc, |
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struct ceph_snap_realm *realm) |
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{ |
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lockdep_assert_held_write(&mdsc->snap_rwsem); |
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dout("__put_snap_realm %llx %p %d -> %d\n", realm->ino, realm, |
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atomic_read(&realm->nref), atomic_read(&realm->nref)-1); |
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if (atomic_dec_and_test(&realm->nref)) |
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__destroy_snap_realm(mdsc, realm); |
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} |
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/* |
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* caller needn't hold any locks |
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*/ |
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void ceph_put_snap_realm(struct ceph_mds_client *mdsc, |
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struct ceph_snap_realm *realm) |
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{ |
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dout("put_snap_realm %llx %p %d -> %d\n", realm->ino, realm, |
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atomic_read(&realm->nref), atomic_read(&realm->nref)-1); |
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if (!atomic_dec_and_test(&realm->nref)) |
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return; |
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if (down_write_trylock(&mdsc->snap_rwsem)) { |
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__destroy_snap_realm(mdsc, realm); |
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up_write(&mdsc->snap_rwsem); |
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} else { |
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spin_lock(&mdsc->snap_empty_lock); |
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list_add(&realm->empty_item, &mdsc->snap_empty); |
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spin_unlock(&mdsc->snap_empty_lock); |
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} |
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} |
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/* |
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* Clean up any realms whose ref counts have dropped to zero. Note |
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* that this does not include realms who were created but not yet |
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* used. |
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* |
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* Called under snap_rwsem (write) |
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*/ |
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static void __cleanup_empty_realms(struct ceph_mds_client *mdsc) |
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{ |
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struct ceph_snap_realm *realm; |
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lockdep_assert_held_write(&mdsc->snap_rwsem); |
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spin_lock(&mdsc->snap_empty_lock); |
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while (!list_empty(&mdsc->snap_empty)) { |
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realm = list_first_entry(&mdsc->snap_empty, |
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struct ceph_snap_realm, empty_item); |
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list_del(&realm->empty_item); |
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spin_unlock(&mdsc->snap_empty_lock); |
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__destroy_snap_realm(mdsc, realm); |
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spin_lock(&mdsc->snap_empty_lock); |
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} |
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spin_unlock(&mdsc->snap_empty_lock); |
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} |
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void ceph_cleanup_empty_realms(struct ceph_mds_client *mdsc) |
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{ |
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down_write(&mdsc->snap_rwsem); |
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__cleanup_empty_realms(mdsc); |
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up_write(&mdsc->snap_rwsem); |
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} |
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/* |
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* adjust the parent realm of a given @realm. adjust child list, and parent |
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* pointers, and ref counts appropriately. |
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* |
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* return true if parent was changed, 0 if unchanged, <0 on error. |
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* |
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* caller must hold snap_rwsem for write. |
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*/ |
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static int adjust_snap_realm_parent(struct ceph_mds_client *mdsc, |
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struct ceph_snap_realm *realm, |
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u64 parentino) |
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{ |
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struct ceph_snap_realm *parent; |
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lockdep_assert_held_write(&mdsc->snap_rwsem); |
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if (realm->parent_ino == parentino) |
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return 0; |
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parent = ceph_lookup_snap_realm(mdsc, parentino); |
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if (!parent) { |
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parent = ceph_create_snap_realm(mdsc, parentino); |
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if (IS_ERR(parent)) |
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return PTR_ERR(parent); |
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} |
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dout("adjust_snap_realm_parent %llx %p: %llx %p -> %llx %p\n", |
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realm->ino, realm, realm->parent_ino, realm->parent, |
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parentino, parent); |
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if (realm->parent) { |
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list_del_init(&realm->child_item); |
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ceph_put_snap_realm(mdsc, realm->parent); |
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} |
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realm->parent_ino = parentino; |
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realm->parent = parent; |
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list_add(&realm->child_item, &parent->children); |
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return 1; |
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} |
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static int cmpu64_rev(const void *a, const void *b) |
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{ |
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if (*(u64 *)a < *(u64 *)b) |
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return 1; |
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if (*(u64 *)a > *(u64 *)b) |
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return -1; |
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return 0; |
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} |
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/* |
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* build the snap context for a given realm. |
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*/ |
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static int build_snap_context(struct ceph_snap_realm *realm, |
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struct list_head* dirty_realms) |
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{ |
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struct ceph_snap_realm *parent = realm->parent; |
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struct ceph_snap_context *snapc; |
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int err = 0; |
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u32 num = realm->num_prior_parent_snaps + realm->num_snaps; |
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|
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/* |
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* build parent context, if it hasn't been built. |
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* conservatively estimate that all parent snaps might be |
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* included by us. |
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*/ |
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if (parent) { |
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if (!parent->cached_context) { |
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err = build_snap_context(parent, dirty_realms); |
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if (err) |
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goto fail; |
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} |
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num += parent->cached_context->num_snaps; |
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} |
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|
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/* do i actually need to update? not if my context seq |
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matches realm seq, and my parents' does to. (this works |
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because we rebuild_snap_realms() works _downward_ in |
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hierarchy after each update.) */ |
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if (realm->cached_context && |
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realm->cached_context->seq == realm->seq && |
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(!parent || |
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realm->cached_context->seq >= parent->cached_context->seq)) { |
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dout("build_snap_context %llx %p: %p seq %lld (%u snaps)" |
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" (unchanged)\n", |
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realm->ino, realm, realm->cached_context, |
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realm->cached_context->seq, |
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(unsigned int)realm->cached_context->num_snaps); |
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return 0; |
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} |
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|
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/* alloc new snap context */ |
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err = -ENOMEM; |
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if (num > (SIZE_MAX - sizeof(*snapc)) / sizeof(u64)) |
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goto fail; |
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snapc = ceph_create_snap_context(num, GFP_NOFS); |
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if (!snapc) |
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goto fail; |
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/* build (reverse sorted) snap vector */ |
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num = 0; |
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snapc->seq = realm->seq; |
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if (parent) { |
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u32 i; |
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|
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/* include any of parent's snaps occurring _after_ my |
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parent became my parent */ |
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for (i = 0; i < parent->cached_context->num_snaps; i++) |
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if (parent->cached_context->snaps[i] >= |
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realm->parent_since) |
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snapc->snaps[num++] = |
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parent->cached_context->snaps[i]; |
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if (parent->cached_context->seq > snapc->seq) |
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snapc->seq = parent->cached_context->seq; |
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} |
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memcpy(snapc->snaps + num, realm->snaps, |
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sizeof(u64)*realm->num_snaps); |
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num += realm->num_snaps; |
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memcpy(snapc->snaps + num, realm->prior_parent_snaps, |
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sizeof(u64)*realm->num_prior_parent_snaps); |
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num += realm->num_prior_parent_snaps; |
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sort(snapc->snaps, num, sizeof(u64), cmpu64_rev, NULL); |
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snapc->num_snaps = num; |
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dout("build_snap_context %llx %p: %p seq %lld (%u snaps)\n", |
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realm->ino, realm, snapc, snapc->seq, |
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(unsigned int) snapc->num_snaps); |
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|
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ceph_put_snap_context(realm->cached_context); |
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realm->cached_context = snapc; |
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/* queue realm for cap_snap creation */ |
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list_add_tail(&realm->dirty_item, dirty_realms); |
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return 0; |
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fail: |
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/* |
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* if we fail, clear old (incorrect) cached_context... hopefully |
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* we'll have better luck building it later |
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*/ |
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if (realm->cached_context) { |
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ceph_put_snap_context(realm->cached_context); |
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realm->cached_context = NULL; |
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} |
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pr_err("build_snap_context %llx %p fail %d\n", realm->ino, |
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realm, err); |
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return err; |
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} |
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|
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/* |
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* rebuild snap context for the given realm and all of its children. |
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*/ |
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static void rebuild_snap_realms(struct ceph_snap_realm *realm, |
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struct list_head *dirty_realms) |
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{ |
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struct ceph_snap_realm *child; |
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dout("rebuild_snap_realms %llx %p\n", realm->ino, realm); |
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build_snap_context(realm, dirty_realms); |
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list_for_each_entry(child, &realm->children, child_item) |
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rebuild_snap_realms(child, dirty_realms); |
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} |
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|
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/* |
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* helper to allocate and decode an array of snapids. free prior |
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* instance, if any. |
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*/ |
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static int dup_array(u64 **dst, __le64 *src, u32 num) |
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{ |
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u32 i; |
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|
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kfree(*dst); |
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if (num) { |
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*dst = kcalloc(num, sizeof(u64), GFP_NOFS); |
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if (!*dst) |
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return -ENOMEM; |
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for (i = 0; i < num; i++) |
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(*dst)[i] = get_unaligned_le64(src + i); |
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} else { |
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*dst = NULL; |
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} |
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return 0; |
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} |
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|
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static bool has_new_snaps(struct ceph_snap_context *o, |
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struct ceph_snap_context *n) |
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{ |
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if (n->num_snaps == 0) |
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return false; |
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/* snaps are in descending order */ |
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return n->snaps[0] > o->seq; |
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} |
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|
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/* |
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* When a snapshot is applied, the size/mtime inode metadata is queued |
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* in a ceph_cap_snap (one for each snapshot) until writeback |
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* completes and the metadata can be flushed back to the MDS. |
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* |
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* However, if a (sync) write is currently in-progress when we apply |
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* the snapshot, we have to wait until the write succeeds or fails |
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* (and a final size/mtime is known). In this case the |
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* cap_snap->writing = 1, and is said to be "pending." When the write |
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* finishes, we __ceph_finish_cap_snap(). |
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* |
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* Caller must hold snap_rwsem for read (i.e., the realm topology won't |
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* change). |
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*/ |
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static void ceph_queue_cap_snap(struct ceph_inode_info *ci) |
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{ |
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struct inode *inode = &ci->vfs_inode; |
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struct ceph_cap_snap *capsnap; |
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struct ceph_snap_context *old_snapc, *new_snapc; |
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struct ceph_buffer *old_blob = NULL; |
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int used, dirty; |
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|
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capsnap = kzalloc(sizeof(*capsnap), GFP_NOFS); |
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if (!capsnap) { |
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pr_err("ENOMEM allocating ceph_cap_snap on %p\n", inode); |
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return; |
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} |
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|
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spin_lock(&ci->i_ceph_lock); |
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used = __ceph_caps_used(ci); |
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dirty = __ceph_caps_dirty(ci); |
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|
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old_snapc = ci->i_head_snapc; |
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new_snapc = ci->i_snap_realm->cached_context; |
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|
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/* |
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* If there is a write in progress, treat that as a dirty Fw, |
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* even though it hasn't completed yet; by the time we finish |
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* up this capsnap it will be. |
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*/ |
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if (used & CEPH_CAP_FILE_WR) |
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dirty |= CEPH_CAP_FILE_WR; |
|
|
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if (__ceph_have_pending_cap_snap(ci)) { |
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/* there is no point in queuing multiple "pending" cap_snaps, |
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as no new writes are allowed to start when pending, so any |
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writes in progress now were started before the previous |
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cap_snap. lucky us. */ |
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dout("queue_cap_snap %p already pending\n", inode); |
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goto update_snapc; |
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} |
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if (ci->i_wrbuffer_ref_head == 0 && |
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!(dirty & (CEPH_CAP_ANY_EXCL|CEPH_CAP_FILE_WR))) { |
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dout("queue_cap_snap %p nothing dirty|writing\n", inode); |
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goto update_snapc; |
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} |
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|
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BUG_ON(!old_snapc); |
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|
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/* |
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* There is no need to send FLUSHSNAP message to MDS if there is |
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* no new snapshot. But when there is dirty pages or on-going |
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* writes, we still need to create cap_snap. cap_snap is needed |
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* by the write path and page writeback path. |
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* |
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* also see ceph_try_drop_cap_snap() |
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*/ |
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if (has_new_snaps(old_snapc, new_snapc)) { |
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if (dirty & (CEPH_CAP_ANY_EXCL|CEPH_CAP_FILE_WR)) |
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capsnap->need_flush = true; |
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} else { |
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if (!(used & CEPH_CAP_FILE_WR) && |
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ci->i_wrbuffer_ref_head == 0) { |
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dout("queue_cap_snap %p " |
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"no new_snap|dirty_page|writing\n", inode); |
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goto update_snapc; |
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} |
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} |
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|
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dout("queue_cap_snap %p cap_snap %p queuing under %p %s %s\n", |
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inode, capsnap, old_snapc, ceph_cap_string(dirty), |
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capsnap->need_flush ? "" : "no_flush"); |
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ihold(inode); |
|
|
|
refcount_set(&capsnap->nref, 1); |
|
INIT_LIST_HEAD(&capsnap->ci_item); |
|
|
|
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) { |
|
dout("queue_cap_snap %p cap_snap %p snapc %p" |
|
" seq %llu used WR, now pending\n", inode, |
|
capsnap, old_snapc, old_snapc->seq); |
|
capsnap->writing = 1; |
|
} else { |
|
/* note mtime, size NOW. */ |
|
__ceph_finish_cap_snap(ci, capsnap); |
|
} |
|
capsnap = 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); |
|
dout(" new snapc is %p\n", new_snapc); |
|
} |
|
spin_unlock(&ci->i_ceph_lock); |
|
|
|
ceph_buffer_put(old_blob); |
|
kfree(capsnap); |
|
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->vfs_inode; |
|
struct ceph_mds_client *mdsc = ceph_sb_to_mdsc(inode->i_sb); |
|
|
|
BUG_ON(capsnap->writing); |
|
capsnap->size = i_size_read(inode); |
|
capsnap->mtime = inode->i_mtime; |
|
capsnap->atime = inode->i_atime; |
|
capsnap->ctime = inode->i_ctime; |
|
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) { |
|
dout("finish_cap_snap %p cap_snap %p snapc %p %llu %s s=%llu " |
|
"still has %d dirty pages\n", inode, capsnap, |
|
capsnap->context, capsnap->context->seq, |
|
ceph_cap_string(capsnap->dirty), capsnap->size, |
|
capsnap->dirty_pages); |
|
return 0; |
|
} |
|
|
|
/* Fb cap still in use, delay it */ |
|
if (ci->i_wb_ref) { |
|
dout("finish_cap_snap %p cap_snap %p snapc %p %llu %s s=%llu " |
|
"used WRBUFFER, delaying\n", inode, capsnap, |
|
capsnap->context, capsnap->context->seq, |
|
ceph_cap_string(capsnap->dirty), capsnap->size); |
|
capsnap->writing = 1; |
|
return 0; |
|
} |
|
|
|
ci->i_ceph_flags |= CEPH_I_FLUSH_SNAPS; |
|
dout("finish_cap_snap %p cap_snap %p snapc %p %llu %s s=%llu\n", |
|
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)) |
|
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_snap_realm *realm) |
|
{ |
|
struct ceph_inode_info *ci; |
|
struct inode *lastinode = NULL; |
|
|
|
dout("queue_realm_cap_snaps %p %llx inodes\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->vfs_inode); |
|
if (!inode) |
|
continue; |
|
spin_unlock(&realm->inodes_with_caps_lock); |
|
iput(lastinode); |
|
lastinode = inode; |
|
ceph_queue_cap_snap(ci); |
|
spin_lock(&realm->inodes_with_caps_lock); |
|
} |
|
spin_unlock(&realm->inodes_with_caps_lock); |
|
iput(lastinode); |
|
|
|
dout("queue_realm_cap_snaps %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_mds_snap_realm *ri; /* encoded */ |
|
__le64 *snaps; /* encoded */ |
|
__le64 *prior_parent_snaps; /* encoded */ |
|
struct ceph_snap_realm *realm = NULL; |
|
struct ceph_snap_realm *first_realm = NULL; |
|
int invalidate = 0; |
|
int err = -ENOMEM; |
|
LIST_HEAD(dirty_realms); |
|
|
|
lockdep_assert_held_write(&mdsc->snap_rwsem); |
|
|
|
dout("update_snap_trace deletion=%d\n", deletion); |
|
more: |
|
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; |
|
invalidate += err; |
|
|
|
if (le64_to_cpu(ri->seq) > realm->seq) { |
|
dout("update_snap_trace 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; |
|
|
|
invalidate = 1; |
|
} else if (!realm->cached_context) { |
|
dout("update_snap_trace %llx %p seq %lld new\n", |
|
realm->ino, realm, realm->seq); |
|
invalidate = 1; |
|
} else { |
|
dout("update_snap_trace %llx %p seq %lld unchanged\n", |
|
realm->ino, realm, realm->seq); |
|
} |
|
|
|
dout("done with %llx %p, invalidated=%d, %p %p\n", realm->ino, |
|
realm, invalidate, p, e); |
|
|
|
/* invalidate when we reach the _end_ (root) of the trace */ |
|
if (invalidate && p >= e) |
|
rebuild_snap_realms(realm, &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(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("update_snap_trace error %d\n", err); |
|
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_inode_info *ci; |
|
struct inode *inode; |
|
struct ceph_mds_session *session = NULL; |
|
|
|
dout("flush_snaps\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->vfs_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); |
|
dout("flush_snaps done\n"); |
|
} |
|
|
|
|
|
/* |
|
* 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 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; |
|
|
|
/* 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); |
|
|
|
dout("handle_snap from mds%d op %s split %llx tracelen %d\n", mds, |
|
ceph_snap_op_name(op), split, trace_len); |
|
|
|
mutex_lock(&session->s_mutex); |
|
inc_session_sequence(session); |
|
mutex_unlock(&session->s_mutex); |
|
|
|
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; |
|
} |
|
|
|
dout("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; |
|
struct ceph_snap_realm *oldrealm; |
|
|
|
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)) { |
|
dout(" leaving %p in newer realm %llx %p\n", |
|
inode, ci->i_snap_realm->ino, |
|
ci->i_snap_realm); |
|
goto skip_inode; |
|
} |
|
dout(" will move %p to split realm %llx %p\n", |
|
inode, realm->ino, realm); |
|
/* |
|
* Move the inode to the new realm |
|
*/ |
|
oldrealm = ci->i_snap_realm; |
|
spin_lock(&oldrealm->inodes_with_caps_lock); |
|
list_del_init(&ci->i_snap_realm_item); |
|
spin_unlock(&oldrealm->inodes_with_caps_lock); |
|
|
|
spin_lock(&realm->inodes_with_caps_lock); |
|
list_add(&ci->i_snap_realm_item, |
|
&realm->inodes_with_caps); |
|
ci->i_snap_realm = realm; |
|
if (realm->ino == ci->i_vino.ino) |
|
realm->inode = inode; |
|
spin_unlock(&realm->inodes_with_caps_lock); |
|
|
|
spin_unlock(&ci->i_ceph_lock); |
|
|
|
ceph_get_snap_realm(mdsc, realm); |
|
ceph_put_snap_realm(mdsc, oldrealm); |
|
|
|
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); |
|
} |
|
} |
|
|
|
/* |
|
* update using the provided snap trace. if we are deleting a |
|
* snap, we can avoid queueing cap_snaps. |
|
*/ |
|
ceph_update_snap_trace(mdsc, p, e, |
|
op == CEPH_SNAP_OP_DESTROY, NULL); |
|
|
|
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); |
|
return; |
|
|
|
bad: |
|
pr_err("corrupt snap message from mds%d\n", mds); |
|
ceph_msg_dump(msg); |
|
out: |
|
if (locked_rwsem) |
|
up_write(&mdsc->snap_rwsem); |
|
return; |
|
} |
|
|
|
struct ceph_snapid_map* ceph_get_snapid_map(struct ceph_mds_client *mdsc, |
|
u64 snap) |
|
{ |
|
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) { |
|
dout("found snapid map %llx -> %x\n", exist->snap, exist->dev); |
|
return exist; |
|
} |
|
|
|
sm = kmalloc(sizeof(*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); |
|
dout("found snapid map %llx -> %x\n", exist->snap, exist->dev); |
|
return exist; |
|
} |
|
|
|
dout("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_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); |
|
dout("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_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("snapid map %llx -> %x still in use\n", |
|
sm->snap, sm->dev); |
|
} |
|
kfree(sm); |
|
} |
|
}
|
|
|