From a213501153fd66e2359e091b1612841305ba6551 Mon Sep 17 00:00:00 2001 From: Chris Mason Date: Wed, 25 Jun 2008 16:01:30 -0400 Subject: Btrfs: Replace the big fs_mutex with a collection of other locks Extent alloctions are still protected by a large alloc_mutex. Objectid allocations are covered by a objectid mutex Other btree operations are protected by a lock on individual btree nodes Signed-off-by: Chris Mason --- fs/btrfs/ctree.c | 40 +++++++++++++++++++++++++++++++++------- 1 file changed, 33 insertions(+), 7 deletions(-) (limited to 'fs/btrfs/ctree.c') diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c index 75625c6..dff4da0 100644 --- a/fs/btrfs/ctree.c +++ b/fs/btrfs/ctree.c @@ -63,6 +63,9 @@ void btrfs_free_path(struct btrfs_path *p) void btrfs_release_path(struct btrfs_root *root, struct btrfs_path *p) { int i; + int skip = p->skip_locking; + int keep = p->keep_locks; + for (i = 0; i < BTRFS_MAX_LEVEL; i++) { if (!p->nodes[i]) continue; @@ -73,6 +76,8 @@ void btrfs_release_path(struct btrfs_root *root, struct btrfs_path *p) free_extent_buffer(p->nodes[i]); } memset(p, 0, sizeof(*p)); + p->skip_locking = skip; + p->keep_locks = keep; } struct extent_buffer *btrfs_root_node(struct btrfs_root *root) @@ -1202,13 +1207,19 @@ static void unlock_up(struct btrfs_path *path, int level, int lowest_unlock) u32 nritems; t = path->nodes[i]; nritems = btrfs_header_nritems(t); - if (path->slots[i] >= nritems - 1) { + if (nritems < 2 || path->slots[i] >= nritems - 2) { +if (path->keep_locks) { +//printk("path %p skip level now %d\n", path, skip_level); +} skip_level = i + 1; continue; } } t = path->nodes[i]; if (i >= lowest_unlock && i > skip_level && path->locks[i]) { +if (path->keep_locks) { +//printk("path %p unlocking level %d slot %d nritems %d skip_level %d\n", path, i, path->slots[i], btrfs_header_nritems(t), skip_level); +} btrfs_tree_unlock(t); path->locks[i] = 0; } @@ -1243,7 +1254,6 @@ int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root lowest_level = p->lowest_level; WARN_ON(lowest_level && ins_len); WARN_ON(p->nodes[0] != NULL); - // WARN_ON(!mutex_is_locked(&root->fs_info->fs_mutex)); WARN_ON(root == root->fs_info->extent_root && !mutex_is_locked(&root->fs_info->alloc_mutex)); WARN_ON(root == root->fs_info->chunk_root && @@ -1321,7 +1331,7 @@ again: b = read_node_slot(root, b, slot); if (!p->skip_locking) btrfs_tree_lock(b); - unlock_up(p, level, lowest_unlock); + unlock_up(p, level + 1, lowest_unlock); } else { p->slots[level] = slot; if (ins_len > 0 && btrfs_leaf_free_space(root, b) < @@ -1804,6 +1814,8 @@ static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root if (slot >= btrfs_header_nritems(upper) - 1) return 1; + WARN_ON(!btrfs_tree_locked(path->nodes[1])); + right = read_node_slot(root, upper, slot + 1); btrfs_tree_lock(right); free_space = btrfs_leaf_free_space(root, right); @@ -1981,6 +1993,8 @@ static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root return 1; } + WARN_ON(!btrfs_tree_locked(path->nodes[1])); + left = read_node_slot(root, path->nodes[1], slot - 1); btrfs_tree_lock(left); free_space = btrfs_leaf_free_space(root, left); @@ -2957,15 +2971,16 @@ int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path) btrfs_item_key_to_cpu(path->nodes[0], &key, nritems - 1); - path->keep_locks = 1; btrfs_release_path(root, path); + path->keep_locks = 1; ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); path->keep_locks = 0; if (ret < 0) return ret; - if (path->slots[0] < nritems - 1) { + nritems = btrfs_header_nritems(path->nodes[0]); + if (nritems > 0 && path->slots[0] < nritems - 1) { goto done; } @@ -2992,8 +3007,17 @@ int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path) reada_for_search(root, path, level, slot, 0); next = read_node_slot(root, c, slot); - if (!path->skip_locking) + if (!path->skip_locking) { + if (!btrfs_tree_locked(c)) { + int i; + WARN_ON(1); +printk("path %p no lock on level %d\n", path, level); +for (i = 0; i < BTRFS_MAX_LEVEL; i++) { +printk("path %p level %d slot %d nritems %d\n", path, i, path->slots[i], btrfs_header_nritems(path->nodes[i])); +} + } btrfs_tree_lock(next); + } break; } path->slots[level] = slot; @@ -3011,8 +3035,10 @@ int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path) if (level == 1 && path->locks[1] && path->reada) reada_for_search(root, path, level, slot, 0); next = read_node_slot(root, next, 0); - if (!path->skip_locking) + if (!path->skip_locking) { + WARN_ON(!btrfs_tree_locked(path->nodes[level])); btrfs_tree_lock(next); + } } done: unlock_up(path, 0, 1); -- cgit v1.1