909 lines
25 KiB
C
909 lines
25 KiB
C
#include "ceph_debug.h"
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#include <linux/sort.h>
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#include <linux/slab.h>
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#include "super.h"
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#include "decode.h"
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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 for write.
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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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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_read(&realm->nref) == 0) {
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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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atomic_inc(&realm->nref);
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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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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, 0); /* tree does not take a ref */
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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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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 for write.
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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 rb_node *n = mdsc->snap_realms.rb_node;
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struct ceph_snap_realm *r;
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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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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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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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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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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(&mdsc->snap_empty, &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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/*
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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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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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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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ceph_get_snap_realm(mdsc, 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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{
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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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int i;
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int num = realm->num_prior_parent_snaps + realm->num_snaps;
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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);
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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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/* 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 (%d 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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realm->cached_context->num_snaps);
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return 0;
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}
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/* alloc new snap context */
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err = -ENOMEM;
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if (num > ULONG_MAX / sizeof(u64) - sizeof(*snapc))
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goto fail;
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snapc = kzalloc(sizeof(*snapc) + num*sizeof(u64), GFP_NOFS);
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if (!snapc)
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goto fail;
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atomic_set(&snapc->nref, 1);
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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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/* include any of parent's snaps occuring _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 (%d snaps)\n",
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realm->ino, realm, snapc, snapc->seq, snapc->num_snaps);
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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 = snapc;
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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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* 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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{
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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);
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list_for_each_entry(child, &realm->children, child_item)
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rebuild_snap_realms(child);
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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, int num)
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{
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int i;
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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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* 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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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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int used, dirty;
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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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spin_lock(&inode->i_lock);
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used = __ceph_caps_used(ci);
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dirty = __ceph_caps_dirty(ci);
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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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kfree(capsnap);
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} else if (ci->i_wrbuffer_ref_head || (used & CEPH_CAP_FILE_WR) ||
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(dirty & (CEPH_CAP_AUTH_EXCL|CEPH_CAP_XATTR_EXCL|
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CEPH_CAP_FILE_EXCL|CEPH_CAP_FILE_WR))) {
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struct ceph_snap_context *snapc = ci->i_head_snapc;
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dout("queue_cap_snap %p cap_snap %p queuing under %p\n", inode,
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capsnap, snapc);
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igrab(inode);
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atomic_set(&capsnap->nref, 1);
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capsnap->ci = ci;
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INIT_LIST_HEAD(&capsnap->ci_item);
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INIT_LIST_HEAD(&capsnap->flushing_item);
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capsnap->follows = snapc->seq;
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capsnap->issued = __ceph_caps_issued(ci, NULL);
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capsnap->dirty = dirty;
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capsnap->mode = inode->i_mode;
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capsnap->uid = inode->i_uid;
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capsnap->gid = inode->i_gid;
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if (dirty & CEPH_CAP_XATTR_EXCL) {
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__ceph_build_xattrs_blob(ci);
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capsnap->xattr_blob =
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ceph_buffer_get(ci->i_xattrs.blob);
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capsnap->xattr_version = ci->i_xattrs.version;
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} else {
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capsnap->xattr_blob = NULL;
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capsnap->xattr_version = 0;
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}
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/* 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 = snapc;
|
|
ci->i_head_snapc =
|
|
ceph_get_snap_context(ci->i_snap_realm->cached_context);
|
|
dout(" new snapc is %p\n", ci->i_head_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, snapc, snapc->seq);
|
|
capsnap->writing = 1;
|
|
} else {
|
|
/* note mtime, size NOW. */
|
|
__ceph_finish_cap_snap(ci, capsnap);
|
|
}
|
|
} else {
|
|
dout("queue_cap_snap %p nothing dirty|writing\n", inode);
|
|
kfree(capsnap);
|
|
}
|
|
|
|
spin_unlock(&inode->i_lock);
|
|
}
|
|
|
|
/*
|
|
* 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_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_client(inode->i_sb)->mdsc;
|
|
|
|
BUG_ON(capsnap->writing);
|
|
capsnap->size = inode->i_size;
|
|
capsnap->mtime = inode->i_mtime;
|
|
capsnap->atime = inode->i_atime;
|
|
capsnap->ctime = inode->i_ctime;
|
|
capsnap->time_warp_seq = ci->i_time_warp_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;
|
|
}
|
|
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);
|
|
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;
|
|
struct ceph_snap_realm *child;
|
|
|
|
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);
|
|
if (lastinode)
|
|
iput(lastinode);
|
|
lastinode = inode;
|
|
ceph_queue_cap_snap(ci);
|
|
spin_lock(&realm->inodes_with_caps_lock);
|
|
}
|
|
spin_unlock(&realm->inodes_with_caps_lock);
|
|
if (lastinode)
|
|
iput(lastinode);
|
|
|
|
dout("queue_realm_cap_snaps %p %llx children\n", realm, realm->ino);
|
|
list_for_each_entry(child, &realm->children, child_item)
|
|
queue_realm_cap_snaps(child);
|
|
|
|
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_mds_snap_realm *ri; /* encoded */
|
|
__le64 *snaps; /* encoded */
|
|
__le64 *prior_parent_snaps; /* encoded */
|
|
struct ceph_snap_realm *realm;
|
|
int invalidate = 0;
|
|
int err = -ENOMEM;
|
|
LIST_HEAD(dirty_realms);
|
|
|
|
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;
|
|
|
|
/* queue realm for cap_snap creation */
|
|
list_add(&realm->dirty_item, &dirty_realms);
|
|
|
|
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);
|
|
|
|
if (p < e)
|
|
goto more;
|
|
|
|
/* invalidate when we reach the _end_ (root) of the trace */
|
|
if (invalidate)
|
|
rebuild_snap_realms(realm);
|
|
|
|
/*
|
|
* queue cap snaps _after_ we've built the new snap contexts,
|
|
* so that i_head_snapc can be set appropriately.
|
|
*/
|
|
list_for_each_entry(realm, &dirty_realms, dirty_item) {
|
|
queue_realm_cap_snaps(realm);
|
|
}
|
|
|
|
__cleanup_empty_realms(mdsc);
|
|
return 0;
|
|
|
|
bad:
|
|
err = -EINVAL;
|
|
fail:
|
|
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;
|
|
igrab(inode);
|
|
spin_unlock(&mdsc->snap_flush_lock);
|
|
spin_lock(&inode->i_lock);
|
|
__ceph_flush_snaps(ci, &session, 0);
|
|
spin_unlock(&inode->i_lock);
|
|
iput(inode);
|
|
spin_lock(&mdsc->snap_flush_lock);
|
|
}
|
|
spin_unlock(&mdsc->snap_flush_lock);
|
|
|
|
if (session) {
|
|
mutex_unlock(&session->s_mutex);
|
|
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->client->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);
|
|
session->s_seq++;
|
|
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;
|
|
}
|
|
ceph_get_snap_realm(mdsc, realm);
|
|
|
|
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(&inode->i_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
|
|
*/
|
|
spin_lock(&realm->inodes_with_caps_lock);
|
|
list_del_init(&ci->i_snap_realm_item);
|
|
list_add(&ci->i_snap_realm_item,
|
|
&realm->inodes_with_caps);
|
|
oldrealm = ci->i_snap_realm;
|
|
ci->i_snap_realm = realm;
|
|
spin_unlock(&realm->inodes_with_caps_lock);
|
|
spin_unlock(&inode->i_lock);
|
|
|
|
ceph_get_snap_realm(mdsc, realm);
|
|
ceph_put_snap_realm(mdsc, oldrealm);
|
|
|
|
iput(inode);
|
|
continue;
|
|
|
|
skip_inode:
|
|
spin_unlock(&inode->i_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 =
|
|
ceph_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);
|
|
|
|
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;
|
|
}
|
|
|
|
|
|
|