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btrfs: allow backref search checks for shared extents
When called with a struct share_check, find_parent_nodes() will detect a shared extent and immediately return with BACKREF_SHARED_FOUND. Signed-off-by: Edmund Nadolski <enadolski@suse.com> Signed-off-by: Jeff Mahoney <jeffm@suse.com> Reviewed-by: Liu Bo <bo.li.liu@oracle.com> Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Edmund Nadolski
David Sterba
parent
9dd14fd696
commit
3ec4d3238a
@ -134,6 +134,25 @@ struct preftrees {
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struct preftree indirect_missing_keys;
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};
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/*
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* Checks for a shared extent during backref search.
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*
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* The share_count tracks prelim_refs (direct and indirect) having a
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* ref->count >0:
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* - incremented when a ref->count transitions to >0
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* - decremented when a ref->count transitions to <1
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*/
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struct share_check {
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u64 root_objectid;
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u64 inum;
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int share_count;
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};
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static inline int extent_is_shared(struct share_check *sc)
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{
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return (sc && sc->share_count > 1) ? BACKREF_FOUND_SHARED : 0;
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}
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static struct kmem_cache *btrfs_prelim_ref_cache;
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int __init btrfs_prelim_ref_init(void)
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@ -194,14 +213,26 @@ static int prelim_ref_compare(struct prelim_ref *ref1,
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return 0;
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}
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void update_share_count(struct share_check *sc, int oldcount, int newcount)
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{
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if ((!sc) || (oldcount == 0 && newcount < 1))
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return;
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if (oldcount > 0 && newcount < 1)
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sc->share_count--;
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else if (oldcount < 1 && newcount > 0)
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sc->share_count++;
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}
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/*
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* Add @newref to the @root rbtree, merging identical refs.
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*
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* Callers should assumed that newref has been freed after calling.
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* Callers should assume that newref has been freed after calling.
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*/
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static void prelim_ref_insert(const struct btrfs_fs_info *fs_info,
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struct preftree *preftree,
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struct prelim_ref *newref)
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struct prelim_ref *newref,
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struct share_check *sc)
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{
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struct rb_root *root;
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struct rb_node **p;
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@ -233,12 +264,20 @@ static void prelim_ref_insert(const struct btrfs_fs_info *fs_info,
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eie->next = newref->inode_list;
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trace_btrfs_prelim_ref_merge(fs_info, ref, newref,
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preftree->count);
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/*
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* A delayed ref can have newref->count < 0.
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* The ref->count is updated to follow any
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* BTRFS_[ADD|DROP]_DELAYED_REF actions.
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*/
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update_share_count(sc, ref->count,
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ref->count + newref->count);
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ref->count += newref->count;
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free_pref(newref);
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return;
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}
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}
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update_share_count(sc, 0, newref->count);
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preftree->count++;
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trace_btrfs_prelim_ref_insert(fs_info, newref, NULL, preftree->count);
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rb_link_node(&newref->rbnode, parent, p);
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@ -302,7 +341,8 @@ static void prelim_release(struct preftree *preftree)
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static int add_prelim_ref(const struct btrfs_fs_info *fs_info,
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struct preftree *preftree, u64 root_id,
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const struct btrfs_key *key, int level, u64 parent,
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u64 wanted_disk_byte, int count, gfp_t gfp_mask)
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u64 wanted_disk_byte, int count,
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struct share_check *sc, gfp_t gfp_mask)
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{
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struct prelim_ref *ref;
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@ -347,32 +387,33 @@ static int add_prelim_ref(const struct btrfs_fs_info *fs_info,
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ref->count = count;
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ref->parent = parent;
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ref->wanted_disk_byte = wanted_disk_byte;
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prelim_ref_insert(fs_info, preftree, ref);
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return 0;
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prelim_ref_insert(fs_info, preftree, ref, sc);
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return extent_is_shared(sc);
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}
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/* direct refs use root == 0, key == NULL */
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static int add_direct_ref(const struct btrfs_fs_info *fs_info,
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struct preftrees *preftrees, int level, u64 parent,
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u64 wanted_disk_byte, int count, gfp_t gfp_mask)
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u64 wanted_disk_byte, int count,
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struct share_check *sc, gfp_t gfp_mask)
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{
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return add_prelim_ref(fs_info, &preftrees->direct, 0, NULL, level,
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parent, wanted_disk_byte, count, gfp_mask);
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parent, wanted_disk_byte, count, sc, gfp_mask);
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}
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/* indirect refs use parent == 0 */
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static int add_indirect_ref(const struct btrfs_fs_info *fs_info,
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struct preftrees *preftrees, u64 root_id,
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const struct btrfs_key *key, int level,
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u64 wanted_disk_byte, int count, gfp_t gfp_mask)
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u64 wanted_disk_byte, int count,
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struct share_check *sc, gfp_t gfp_mask)
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{
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struct preftree *tree = &preftrees->indirect;
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if (!key)
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tree = &preftrees->indirect_missing_keys;
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return add_prelim_ref(fs_info, tree, root_id, key, level, 0,
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wanted_disk_byte, count, gfp_mask);
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wanted_disk_byte, count, sc, gfp_mask);
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}
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static int add_all_parents(struct btrfs_root *root, struct btrfs_path *path,
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@ -575,7 +616,7 @@ static int resolve_indirect_refs(struct btrfs_fs_info *fs_info,
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struct btrfs_path *path, u64 time_seq,
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struct preftrees *preftrees,
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const u64 *extent_item_pos, u64 total_refs,
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u64 root_objectid)
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struct share_check *sc)
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{
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int err;
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int ret = 0;
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@ -612,7 +653,8 @@ static int resolve_indirect_refs(struct btrfs_fs_info *fs_info,
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continue;
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}
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if (root_objectid && ref->root_id != root_objectid) {
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if (sc && sc->root_objectid &&
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ref->root_id != sc->root_objectid) {
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free_pref(ref);
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ret = BACKREF_FOUND_SHARED;
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goto out;
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@ -625,7 +667,8 @@ static int resolve_indirect_refs(struct btrfs_fs_info *fs_info,
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* and return directly.
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*/
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if (err == -ENOENT) {
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prelim_ref_insert(fs_info, &preftrees->direct, ref);
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prelim_ref_insert(fs_info, &preftrees->direct, ref,
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NULL);
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continue;
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} else if (err) {
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free_pref(ref);
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@ -653,11 +696,15 @@ static int resolve_indirect_refs(struct btrfs_fs_info *fs_info,
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memcpy(new_ref, ref, sizeof(*ref));
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new_ref->parent = node->val;
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new_ref->inode_list = unode_aux_to_inode_list(node);
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prelim_ref_insert(fs_info, &preftrees->direct, new_ref);
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prelim_ref_insert(fs_info, &preftrees->direct,
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new_ref, NULL);
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}
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/* Now it's a direct ref, put it in the the direct tree */
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prelim_ref_insert(fs_info, &preftrees->direct, ref);
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/*
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* Now it's a direct ref, put it in the the direct tree. We must
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* do this last because the ref could be merged/freed here.
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*/
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prelim_ref_insert(fs_info, &preftrees->direct, ref, NULL);
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ulist_reinit(parents);
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cond_resched();
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@ -702,7 +749,7 @@ static int add_missing_keys(struct btrfs_fs_info *fs_info,
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btrfs_node_key_to_cpu(eb, &ref->key_for_search, 0);
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btrfs_tree_read_unlock(eb);
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free_extent_buffer(eb);
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prelim_ref_insert(fs_info, &preftrees->indirect, ref);
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prelim_ref_insert(fs_info, &preftrees->indirect, ref, NULL);
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cond_resched();
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}
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return 0;
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@ -715,7 +762,7 @@ static int add_missing_keys(struct btrfs_fs_info *fs_info,
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static int add_delayed_refs(const struct btrfs_fs_info *fs_info,
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struct btrfs_delayed_ref_head *head, u64 seq,
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struct preftrees *preftrees, u64 *total_refs,
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u64 inum)
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struct share_check *sc)
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{
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struct btrfs_delayed_ref_node *node;
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struct btrfs_delayed_extent_op *extent_op = head->extent_op;
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@ -760,7 +807,7 @@ static int add_delayed_refs(const struct btrfs_fs_info *fs_info,
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&tmp_op_key, ref->level + 1,
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node->bytenr,
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node->ref_mod * sgn,
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GFP_ATOMIC);
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sc, GFP_ATOMIC);
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break;
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}
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case BTRFS_SHARED_BLOCK_REF_KEY: {
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@ -772,7 +819,7 @@ static int add_delayed_refs(const struct btrfs_fs_info *fs_info,
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ret = add_direct_ref(fs_info, preftrees,
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ref->level + 1, ref->parent,
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node->bytenr, node->ref_mod * sgn,
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GFP_ATOMIC);
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sc, GFP_ATOMIC);
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break;
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}
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case BTRFS_EXTENT_DATA_REF_KEY: {
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@ -788,15 +835,15 @@ static int add_delayed_refs(const struct btrfs_fs_info *fs_info,
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* Found a inum that doesn't match our known inum, we
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* know it's shared.
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*/
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if (inum && ref->objectid != inum) {
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if (sc && sc->inum && ref->objectid != sc->inum) {
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ret = BACKREF_FOUND_SHARED;
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break;
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goto out;
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}
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ret = add_indirect_ref(fs_info, preftrees, ref->root,
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&key, 0, node->bytenr,
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node->ref_mod * sgn,
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GFP_ATOMIC);
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sc, GFP_ATOMIC);
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break;
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}
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case BTRFS_SHARED_DATA_REF_KEY: {
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@ -808,26 +855,35 @@ static int add_delayed_refs(const struct btrfs_fs_info *fs_info,
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ret = add_direct_ref(fs_info, preftrees, 0,
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ref->parent, node->bytenr,
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node->ref_mod * sgn,
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GFP_ATOMIC);
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sc, GFP_ATOMIC);
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break;
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}
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default:
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WARN_ON(1);
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}
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if (ret)
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/*
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* We must ignore BACKREF_FOUND_SHARED until all delayed
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* refs have been checked.
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*/
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if (ret && (ret != BACKREF_FOUND_SHARED))
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break;
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}
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if (!ret)
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ret = extent_is_shared(sc);
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out:
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spin_unlock(&head->lock);
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return ret;
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}
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/*
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* add all inline backrefs for bytenr to the list
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*
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* Returns 0 on success, <0 on error, or BACKREF_FOUND_SHARED.
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*/
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static int add_inline_refs(const struct btrfs_fs_info *fs_info,
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struct btrfs_path *path, u64 bytenr,
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int *info_level, struct preftrees *preftrees,
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u64 *total_refs, u64 inum)
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u64 *total_refs, struct share_check *sc)
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{
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int ret = 0;
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int slot;
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@ -884,7 +940,7 @@ static int add_inline_refs(const struct btrfs_fs_info *fs_info,
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case BTRFS_SHARED_BLOCK_REF_KEY:
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ret = add_direct_ref(fs_info, preftrees,
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*info_level + 1, offset,
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bytenr, 1, GFP_NOFS);
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bytenr, 1, NULL, GFP_NOFS);
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break;
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case BTRFS_SHARED_DATA_REF_KEY: {
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struct btrfs_shared_data_ref *sdref;
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@ -894,13 +950,13 @@ static int add_inline_refs(const struct btrfs_fs_info *fs_info,
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count = btrfs_shared_data_ref_count(leaf, sdref);
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ret = add_direct_ref(fs_info, preftrees, 0, offset,
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bytenr, count, GFP_NOFS);
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bytenr, count, sc, GFP_NOFS);
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break;
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}
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case BTRFS_TREE_BLOCK_REF_KEY:
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ret = add_indirect_ref(fs_info, preftrees, offset,
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NULL, *info_level + 1,
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bytenr, 1, GFP_NOFS);
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bytenr, 1, NULL, GFP_NOFS);
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break;
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case BTRFS_EXTENT_DATA_REF_KEY: {
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struct btrfs_extent_data_ref *dref;
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@ -914,7 +970,7 @@ static int add_inline_refs(const struct btrfs_fs_info *fs_info,
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key.type = BTRFS_EXTENT_DATA_KEY;
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key.offset = btrfs_extent_data_ref_offset(leaf, dref);
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if (inum && key.objectid != inum) {
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if (sc && sc->inum && key.objectid != sc->inum) {
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ret = BACKREF_FOUND_SHARED;
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break;
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}
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@ -923,7 +979,7 @@ static int add_inline_refs(const struct btrfs_fs_info *fs_info,
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ret = add_indirect_ref(fs_info, preftrees, root,
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&key, 0, bytenr, count,
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GFP_NOFS);
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sc, GFP_NOFS);
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break;
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}
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default:
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@ -939,11 +995,13 @@ static int add_inline_refs(const struct btrfs_fs_info *fs_info,
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/*
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* add all non-inline backrefs for bytenr to the list
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*
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* Returns 0 on success, <0 on error, or BACKREF_FOUND_SHARED.
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*/
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static int add_keyed_refs(struct btrfs_fs_info *fs_info,
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struct btrfs_path *path, u64 bytenr,
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int info_level, struct preftrees *preftrees,
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u64 inum)
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struct share_check *sc)
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{
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struct btrfs_root *extent_root = fs_info->extent_root;
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int ret;
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@ -976,7 +1034,7 @@ static int add_keyed_refs(struct btrfs_fs_info *fs_info,
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/* SHARED DIRECT METADATA backref */
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ret = add_direct_ref(fs_info, preftrees,
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info_level + 1, key.offset,
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bytenr, 1, GFP_NOFS);
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bytenr, 1, NULL, GFP_NOFS);
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break;
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case BTRFS_SHARED_DATA_REF_KEY: {
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/* SHARED DIRECT FULL backref */
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@ -988,14 +1046,14 @@ static int add_keyed_refs(struct btrfs_fs_info *fs_info,
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count = btrfs_shared_data_ref_count(leaf, sdref);
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ret = add_direct_ref(fs_info, preftrees, 0,
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key.offset, bytenr, count,
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GFP_NOFS);
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sc, GFP_NOFS);
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break;
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}
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case BTRFS_TREE_BLOCK_REF_KEY:
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/* NORMAL INDIRECT METADATA backref */
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ret = add_indirect_ref(fs_info, preftrees, key.offset,
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NULL, info_level + 1, bytenr,
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1, GFP_NOFS);
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1, NULL, GFP_NOFS);
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break;
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case BTRFS_EXTENT_DATA_REF_KEY: {
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/* NORMAL INDIRECT DATA backref */
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@ -1011,7 +1069,7 @@ static int add_keyed_refs(struct btrfs_fs_info *fs_info,
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key.type = BTRFS_EXTENT_DATA_KEY;
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key.offset = btrfs_extent_data_ref_offset(leaf, dref);
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if (inum && key.objectid != inum) {
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if (sc && sc->inum && key.objectid != sc->inum) {
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ret = BACKREF_FOUND_SHARED;
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break;
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}
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@ -1019,7 +1077,7 @@ static int add_keyed_refs(struct btrfs_fs_info *fs_info,
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root = btrfs_extent_data_ref_root(leaf, dref);
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ret = add_indirect_ref(fs_info, preftrees, root,
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&key, 0, bytenr, count,
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GFP_NOFS);
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sc, GFP_NOFS);
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break;
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}
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default:
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@ -1039,20 +1097,23 @@ static int add_keyed_refs(struct btrfs_fs_info *fs_info,
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* indirect refs to their parent bytenr.
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* When roots are found, they're added to the roots list
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*
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* NOTE: This can return values > 0
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*
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* If time_seq is set to SEQ_LAST, it will not search delayed_refs, and behave
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* much like trans == NULL case, the difference only lies in it will not
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* commit root.
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* The special case is for qgroup to search roots in commit_transaction().
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*
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* @sc - if !NULL, then immediately return BACKREF_FOUND_SHARED when a
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* shared extent is detected.
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*
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* Otherwise this returns 0 for success and <0 for an error.
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*
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* FIXME some caching might speed things up
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*/
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static int find_parent_nodes(struct btrfs_trans_handle *trans,
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struct btrfs_fs_info *fs_info, u64 bytenr,
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u64 time_seq, struct ulist *refs,
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struct ulist *roots, const u64 *extent_item_pos,
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u64 root_objectid, u64 inum)
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struct share_check *sc)
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{
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struct btrfs_key key;
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struct btrfs_path *path;
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@ -1133,7 +1194,7 @@ again:
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}
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spin_unlock(&delayed_refs->lock);
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ret = add_delayed_refs(fs_info, head, time_seq,
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&preftrees, &total_refs, inum);
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&preftrees, &total_refs, sc);
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mutex_unlock(&head->mutex);
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if (ret)
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goto out;
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@ -1155,11 +1216,11 @@ again:
|
||||
key.type == BTRFS_METADATA_ITEM_KEY)) {
|
||||
ret = add_inline_refs(fs_info, path, bytenr,
|
||||
&info_level, &preftrees,
|
||||
&total_refs, inum);
|
||||
&total_refs, sc);
|
||||
if (ret)
|
||||
goto out;
|
||||
ret = add_keyed_refs(fs_info, path, bytenr, info_level,
|
||||
&preftrees, inum);
|
||||
&preftrees, sc);
|
||||
if (ret)
|
||||
goto out;
|
||||
}
|
||||
@ -1174,8 +1235,7 @@ again:
|
||||
WARN_ON(!RB_EMPTY_ROOT(&preftrees.indirect_missing_keys.root));
|
||||
|
||||
ret = resolve_indirect_refs(fs_info, path, time_seq, &preftrees,
|
||||
extent_item_pos, total_refs,
|
||||
root_objectid);
|
||||
extent_item_pos, total_refs, sc);
|
||||
if (ret)
|
||||
goto out;
|
||||
|
||||
@ -1194,7 +1254,8 @@ again:
|
||||
node = rb_next(&ref->rbnode);
|
||||
WARN_ON(ref->count < 0);
|
||||
if (roots && ref->count && ref->root_id && ref->parent == 0) {
|
||||
if (root_objectid && ref->root_id != root_objectid) {
|
||||
if (sc && sc->root_objectid &&
|
||||
ref->root_id != sc->root_objectid) {
|
||||
ret = BACKREF_FOUND_SHARED;
|
||||
goto out;
|
||||
}
|
||||
@ -1298,7 +1359,7 @@ static int btrfs_find_all_leafs(struct btrfs_trans_handle *trans,
|
||||
return -ENOMEM;
|
||||
|
||||
ret = find_parent_nodes(trans, fs_info, bytenr, time_seq,
|
||||
*leafs, NULL, extent_item_pos, 0, 0);
|
||||
*leafs, NULL, extent_item_pos, NULL);
|
||||
if (ret < 0 && ret != -ENOENT) {
|
||||
free_leaf_list(*leafs);
|
||||
return ret;
|
||||
@ -1341,7 +1402,7 @@ static int btrfs_find_all_roots_safe(struct btrfs_trans_handle *trans,
|
||||
ULIST_ITER_INIT(&uiter);
|
||||
while (1) {
|
||||
ret = find_parent_nodes(trans, fs_info, bytenr, time_seq,
|
||||
tmp, *roots, NULL, 0, 0);
|
||||
tmp, *roots, NULL, NULL);
|
||||
if (ret < 0 && ret != -ENOENT) {
|
||||
ulist_free(tmp);
|
||||
ulist_free(*roots);
|
||||
@ -1397,6 +1458,11 @@ int btrfs_check_shared(struct btrfs_root *root, u64 inum, u64 bytenr)
|
||||
struct ulist_node *node;
|
||||
struct seq_list elem = SEQ_LIST_INIT(elem);
|
||||
int ret = 0;
|
||||
struct share_check shared = {
|
||||
.root_objectid = root->objectid,
|
||||
.inum = inum,
|
||||
.share_count = 0,
|
||||
};
|
||||
|
||||
tmp = ulist_alloc(GFP_NOFS);
|
||||
roots = ulist_alloc(GFP_NOFS);
|
||||
@ -1417,7 +1483,7 @@ int btrfs_check_shared(struct btrfs_root *root, u64 inum, u64 bytenr)
|
||||
ULIST_ITER_INIT(&uiter);
|
||||
while (1) {
|
||||
ret = find_parent_nodes(trans, fs_info, bytenr, elem.seq, tmp,
|
||||
roots, NULL, root->objectid, inum);
|
||||
roots, NULL, &shared);
|
||||
if (ret == BACKREF_FOUND_SHARED) {
|
||||
/* this is the only condition under which we return 1 */
|
||||
ret = 1;
|
||||
|
||||
Loading…
Reference in New Issue
Block a user