return 0;
}
+/*
+ * This allocates memory and gets a tree modification sequence number when
+ * needed.
+ *
+ * Returns 0 when no sequence number is needed, < 0 on error.
+ * Returns 1 when a sequence number was added. In this case,
+ * fs_info->tree_mod_seq_lock was acquired and must be released by the caller
+ * after inserting into the rb tree.
+ */
static inline int tree_mod_alloc(struct btrfs_fs_info *fs_info, gfp_t flags,
struct tree_mod_elem **tm_ret)
{
*/
kfree(tm);
seq = 0;
+ spin_unlock(&fs_info->tree_mod_seq_lock);
} else {
__get_tree_mod_seq(fs_info, &tm->elem);
seq = tm->elem.seq;
}
- spin_unlock(&fs_info->tree_mod_seq_lock);
return seq;
}
tm->slot = slot;
tm->generation = btrfs_node_ptr_generation(eb, slot);
- return __tree_mod_log_insert(fs_info, tm);
+ ret = __tree_mod_log_insert(fs_info, tm);
+ spin_unlock(&fs_info->tree_mod_seq_lock);
+ return ret;
}
static noinline int
tm->move.nr_items = nr_items;
tm->op = MOD_LOG_MOVE_KEYS;
- return __tree_mod_log_insert(fs_info, tm);
+ ret = __tree_mod_log_insert(fs_info, tm);
+ spin_unlock(&fs_info->tree_mod_seq_lock);
+ return ret;
}
static noinline int
tm->generation = btrfs_header_generation(old_root);
tm->op = MOD_LOG_ROOT_REPLACE;
- return __tree_mod_log_insert(fs_info, tm);
+ ret = __tree_mod_log_insert(fs_info, tm);
+ spin_unlock(&fs_info->tree_mod_seq_lock);
+ return ret;
}
static struct tree_mod_elem *
looped = 1;
}
+ /* if there's no old root to return, return what we found instead */
+ if (!found)
+ found = tm;
+
return found;
}
return eb_rewin;
}
+/*
+ * get_old_root() rewinds the state of @root's root node to the given @time_seq
+ * value. If there are no changes, the current root->root_node is returned. If
+ * anything changed in between, there's a fresh buffer allocated on which the
+ * rewind operations are done. In any case, the returned buffer is read locked.
+ * Returns NULL on error (with no locks held).
+ */
static inline struct extent_buffer *
get_old_root(struct btrfs_root *root, u64 time_seq)
{
struct tree_mod_elem *tm;
struct extent_buffer *eb;
- struct tree_mod_root *old_root;
- u64 old_generation;
+ struct tree_mod_root *old_root = NULL;
+ u64 old_generation = 0;
+ u64 logical;
+ eb = btrfs_read_lock_root_node(root);
tm = __tree_mod_log_oldest_root(root->fs_info, root, time_seq);
if (!tm)
return root->node;
- old_root = &tm->old_root;
- old_generation = tm->generation;
+ if (tm->op == MOD_LOG_ROOT_REPLACE) {
+ old_root = &tm->old_root;
+ old_generation = tm->generation;
+ logical = old_root->logical;
+ } else {
+ logical = root->node->start;
+ }
- tm = tree_mod_log_search(root->fs_info, old_root->logical, time_seq);
+ tm = tree_mod_log_search(root->fs_info, logical, time_seq);
/*
* there was an item in the log when __tree_mod_log_oldest_root
* returned. this one must not go away, because the time_seq passed to
*/
BUG_ON(!tm);
- if (old_root->logical == root->node->start) {
- /* there are logged operations for the current root */
- eb = btrfs_clone_extent_buffer(root->node);
- } else {
- /* there's a root replace operation for the current root */
+ if (old_root)
eb = alloc_dummy_extent_buffer(tm->index << PAGE_CACHE_SHIFT,
root->nodesize);
+ else
+ eb = btrfs_clone_extent_buffer(root->node);
+ btrfs_tree_read_unlock(root->node);
+ free_extent_buffer(root->node);
+ if (!eb)
+ return NULL;
+ btrfs_tree_read_lock(eb);
+ if (old_root) {
btrfs_set_header_bytenr(eb, eb->start);
btrfs_set_header_backref_rev(eb, BTRFS_MIXED_BACKREF_REV);
btrfs_set_header_owner(eb, root->root_key.objectid);
+ btrfs_set_header_level(eb, old_root->level);
+ btrfs_set_header_generation(eb, old_generation);
}
- if (!eb)
- return NULL;
- btrfs_set_header_level(eb, old_root->level);
- btrfs_set_header_generation(eb, old_generation);
__tree_mod_log_rewind(eb, time_seq, tm);
+ extent_buffer_get(eb);
return eb;
}
BTRFS_NODEPTRS_PER_BLOCK(root) / 4)
return 0;
- btrfs_header_nritems(mid);
-
left = read_node_slot(root, parent, pslot - 1);
if (left) {
btrfs_tree_lock(left);
wret = push_node_left(trans, root, left, mid, 1);
if (wret < 0)
ret = wret;
- btrfs_header_nritems(mid);
}
/*
again:
b = get_old_root(root, time_seq);
- extent_buffer_get(b);
level = btrfs_header_level(b);
- btrfs_tree_read_lock(b);
p->locks[level] = BTRFS_READ_LOCK;
while (b) {
* returns < 0 on io errors.
*/
int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path)
+{
+ return btrfs_next_old_leaf(root, path, 0);
+}
+
+int btrfs_next_old_leaf(struct btrfs_root *root, struct btrfs_path *path,
+ u64 time_seq)
{
int slot;
int level;
path->keep_locks = 1;
path->leave_spinning = 1;
- ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
+ if (time_seq)
+ ret = btrfs_search_old_slot(root, &key, path, time_seq);
+ else
+ ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
path->keep_locks = 0;
if (ret < 0)
projects / karo-tx-linux.git / blobdiff