diff options
Diffstat (limited to 'fs/btrfs/ctree.c')
| -rw-r--r-- | fs/btrfs/ctree.c | 234 |
1 files changed, 226 insertions, 8 deletions
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c index 3b6e35aafc9e..3af777357acb 100644 --- a/fs/btrfs/ctree.c +++ b/fs/btrfs/ctree.c @@ -54,6 +54,31 @@ struct btrfs_path *btrfs_alloc_path(void) return path; } +/* + * set all locked nodes in the path to blocking locks. This should + * be done before scheduling + */ +noinline void btrfs_set_path_blocking(struct btrfs_path *p) +{ + int i; + for (i = 0; i < BTRFS_MAX_LEVEL; i++) { + if (p->nodes[i] && p->locks[i]) + btrfs_set_lock_blocking(p->nodes[i]); + } +} + +/* + * reset all the locked nodes in the patch to spinning locks. + */ +noinline void btrfs_clear_path_blocking(struct btrfs_path *p) +{ + int i; + for (i = 0; i < BTRFS_MAX_LEVEL; i++) { + if (p->nodes[i] && p->locks[i]) + btrfs_clear_lock_blocking(p->nodes[i]); + } +} + /* this also releases the path */ void btrfs_free_path(struct btrfs_path *p) { @@ -272,6 +297,8 @@ static noinline int __btrfs_cow_block(struct btrfs_trans_handle *trans, if (IS_ERR(cow)) return PTR_ERR(cow); + /* cow is set to blocking by btrfs_init_new_buffer */ + copy_extent_buffer(cow, buf, 0, 0, cow->len); btrfs_set_header_bytenr(cow, cow->start); btrfs_set_header_generation(cow, trans->transid); @@ -397,6 +424,11 @@ noinline int btrfs_cow_block(struct btrfs_trans_handle *trans, } search_start = buf->start & ~((u64)(1024 * 1024 * 1024) - 1); + + if (parent) + btrfs_set_lock_blocking(parent); + btrfs_set_lock_blocking(buf); + ret = __btrfs_cow_block(trans, root, buf, parent, parent_slot, cow_ret, search_start, 0, prealloc_dest); @@ -502,6 +534,8 @@ int btrfs_realloc_node(struct btrfs_trans_handle *trans, if (parent_nritems == 1) return 0; + btrfs_set_lock_blocking(parent); + for (i = start_slot; i < end_slot; i++) { int close = 1; @@ -562,6 +596,7 @@ int btrfs_realloc_node(struct btrfs_trans_handle *trans, search_start = last_block; btrfs_tree_lock(cur); + btrfs_set_lock_blocking(cur); err = __btrfs_cow_block(trans, root, cur, parent, i, &cur, search_start, min(16 * blocksize, @@ -860,6 +895,7 @@ static noinline int balance_level(struct btrfs_trans_handle *trans, return 0; mid = path->nodes[level]; + WARN_ON(!path->locks[level]); WARN_ON(btrfs_header_generation(mid) != trans->transid); @@ -882,6 +918,7 @@ static noinline int balance_level(struct btrfs_trans_handle *trans, /* promote the child to a root */ child = read_node_slot(root, mid, 0); btrfs_tree_lock(child); + btrfs_set_lock_blocking(child); BUG_ON(!child); ret = btrfs_cow_block(trans, root, child, mid, 0, &child, 0); BUG_ON(ret); @@ -898,6 +935,7 @@ static noinline int balance_level(struct btrfs_trans_handle *trans, add_root_to_dirty_list(root); btrfs_tree_unlock(child); + path->locks[level] = 0; path->nodes[level] = NULL; clean_tree_block(trans, root, mid); @@ -922,6 +960,7 @@ static noinline int balance_level(struct btrfs_trans_handle *trans, left = read_node_slot(root, parent, pslot - 1); if (left) { btrfs_tree_lock(left); + btrfs_set_lock_blocking(left); wret = btrfs_cow_block(trans, root, left, parent, pslot - 1, &left, 0); if (wret) { @@ -932,6 +971,7 @@ static noinline int balance_level(struct btrfs_trans_handle *trans, right = read_node_slot(root, parent, pslot + 1); if (right) { btrfs_tree_lock(right); + btrfs_set_lock_blocking(right); wret = btrfs_cow_block(trans, root, right, parent, pslot + 1, &right, 0); if (wret) { @@ -1107,6 +1147,8 @@ static noinline int push_nodes_for_insert(struct btrfs_trans_handle *trans, u32 left_nr; btrfs_tree_lock(left); + btrfs_set_lock_blocking(left); + left_nr = btrfs_header_nritems(left); if (left_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) { wret = 1; @@ -1153,7 +1195,10 @@ static noinline int push_nodes_for_insert(struct btrfs_trans_handle *trans, */ if (right) { u32 right_nr; + btrfs_tree_lock(right); + btrfs_set_lock_blocking(right); + right_nr = btrfs_header_nritems(right); if (right_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) { wret = 1; @@ -1265,6 +1310,68 @@ static noinline void reada_for_search(struct btrfs_root *root, } /* + * returns -EAGAIN if it had to drop the path, or zero if everything was in + * cache + */ +static noinline int reada_for_balance(struct btrfs_root *root, + struct btrfs_path *path, int level) +{ + int slot; + int nritems; + struct extent_buffer *parent; + struct extent_buffer *eb; + u64 gen; + u64 block1 = 0; + u64 block2 = 0; + int ret = 0; + int blocksize; + + parent = path->nodes[level - 1]; + if (!parent) + return 0; + + nritems = btrfs_header_nritems(parent); + slot = path->slots[level]; + blocksize = btrfs_level_size(root, level); + + if (slot > 0) { + block1 = btrfs_node_blockptr(parent, slot - 1); + gen = btrfs_node_ptr_generation(parent, slot - 1); + eb = btrfs_find_tree_block(root, block1, blocksize); + if (eb && btrfs_buffer_uptodate(eb, gen)) + block1 = 0; + free_extent_buffer(eb); + } + if (slot < nritems) { + block2 = btrfs_node_blockptr(parent, slot + 1); + gen = btrfs_node_ptr_generation(parent, slot + 1); + eb = btrfs_find_tree_block(root, block2, blocksize); + if (eb && btrfs_buffer_uptodate(eb, gen)) + block2 = 0; + free_extent_buffer(eb); + } + if (block1 || block2) { + ret = -EAGAIN; + btrfs_release_path(root, path); + if (block1) + readahead_tree_block(root, block1, blocksize, 0); + if (block2) + readahead_tree_block(root, block2, blocksize, 0); + + if (block1) { + eb = read_tree_block(root, block1, blocksize, 0); + free_extent_buffer(eb); + } + if (block1) { + eb = read_tree_block(root, block2, blocksize, 0); + free_extent_buffer(eb); + } + } + return ret; +} + + +/* * when we walk down the tree, it is usually safe to unlock the higher layers * in the tree. The exceptions are when our path goes through slot 0, because * operations on the tree might require changing key pointers higher up in the @@ -1315,6 +1422,32 @@ static noinline void unlock_up(struct btrfs_path *path, int level, } /* + * This releases any locks held in the path starting at level and + * going all the way up to the root. + * + * btrfs_search_slot will keep the lock held on higher nodes in a few + * corner cases, such as COW of the block at slot zero in the node. This + * ignores those rules, and it should only be called when there are no + * more updates to be done higher up in the tree. + */ +noinline void btrfs_unlock_up_safe(struct btrfs_path *path, int level) +{ + int i; + + if (path->keep_locks || path->lowest_level) + return; + + for (i = level; i < BTRFS_MAX_LEVEL; i++) { + if (!path->nodes[i]) + break; + if (!path->locks[i]) + break; + btrfs_tree_unlock(path->nodes[i]); + path->locks[i] = 0; + } +} + +/* * look for key in the tree. path is filled in with nodes along the way * if key is found, we return zero and you can find the item in the leaf * level of the path (level 0) @@ -1385,6 +1518,7 @@ again: */ if (prealloc_block.objectid && prealloc_block.offset != b->len) { + btrfs_set_path_blocking(p); btrfs_free_reserved_extent(root, prealloc_block.objectid, prealloc_block.offset); @@ -1409,6 +1543,8 @@ again: goto again; } + btrfs_set_path_blocking(p); + wret = btrfs_cow_block(trans, root, b, p->nodes[level + 1], p->slots[level + 1], @@ -1430,6 +1566,22 @@ cow_done: if (!p->skip_locking) p->locks[level] = 1; + btrfs_clear_path_blocking(p); + + /* + * we have a lock on b and as long as we aren't changing + * the tree, there is no way to for the items in b to change. + * It is safe to drop the lock on our parent before we + * go through the expensive btree search on b. + * + * If cow is true, then we might be changing slot zero, + * which may require changing the parent. So, we can't + * drop the lock until after we know which slot we're + * operating on. + */ + if (!cow) + btrfs_unlock_up_safe(p, level + 1); + ret = check_block(root, p, level); if (ret) { ret = -1; @@ -1437,6 +1589,7 @@ cow_done: } ret = bin_search(b, key, level, &slot); + if (level != 0) { if (ret && slot > 0) slot -= 1; @@ -1444,7 +1597,16 @@ cow_done: if ((p->search_for_split || ins_len > 0) && btrfs_header_nritems(b) >= BTRFS_NODEPTRS_PER_BLOCK(root) - 3) { - int sret = split_node(trans, root, p, level); + int sret; + + sret = reada_for_balance(root, p, level); + if (sret) + goto again; + + btrfs_set_path_blocking(p); + sret = split_node(trans, root, p, level); + btrfs_clear_path_blocking(p); + BUG_ON(sret > 0); if (sret) { ret = sret; @@ -1453,8 +1615,16 @@ cow_done: b = p->nodes[level]; slot = p->slots[level]; } else if (ins_len < 0) { - int sret = balance_level(trans, root, p, - level); + int sret; + + sret = reada_for_balance(root, p, level); + if (sret) + goto again; + + btrfs_set_path_blocking(p); + sret = balance_level(trans, root, p, level); + btrfs_clear_path_blocking(p); + if (sret) { ret = sret; goto done; @@ -1488,7 +1658,7 @@ cow_done: * of the btree by dropping locks before * we read. */ - if (level > 1) { + if (level > 0) { btrfs_release_path(NULL, p); if (tmp) free_extent_buffer(tmp); @@ -1503,6 +1673,7 @@ cow_done: free_extent_buffer(tmp); goto again; } else { + btrfs_set_path_blocking(p); if (tmp) free_extent_buffer(tmp); if (should_reada) @@ -1512,14 +1683,29 @@ cow_done: b = read_node_slot(root, b, slot); } } - if (!p->skip_locking) - btrfs_tree_lock(b); + if (!p->skip_locking) { + int lret; + + btrfs_clear_path_blocking(p); + lret = btrfs_try_spin_lock(b); + + if (!lret) { + btrfs_set_path_blocking(p); + btrfs_tree_lock(b); + btrfs_clear_path_blocking(p); + } + } } else { p->slots[level] = slot; if (ins_len > 0 && btrfs_leaf_free_space(root, b) < ins_len) { - int sret = split_leaf(trans, root, key, + int sret; + + btrfs_set_path_blocking(p); + sret = split_leaf(trans, root, key, p, ins_len, ret == 0); + btrfs_clear_path_blocking(p); + BUG_ON(sret > 0); if (sret) { ret = sret; @@ -1533,12 +1719,16 @@ cow_done: } ret = 1; done: + /* + * we don't really know what they plan on doing with the path + * from here on, so for now just mark it as blocking + */ + btrfs_set_path_blocking(p); if (prealloc_block.objectid) { btrfs_free_reserved_extent(root, prealloc_block.objectid, prealloc_block.offset); } - return ret; } @@ -1562,6 +1752,8 @@ int btrfs_merge_path(struct btrfs_trans_handle *trans, ret = btrfs_cow_block(trans, root, eb, NULL, 0, &eb, 0); BUG_ON(ret); + btrfs_set_lock_blocking(eb); + parent = eb; while (1) { level = btrfs_header_level(parent); @@ -1586,6 +1778,7 @@ int btrfs_merge_path(struct btrfs_trans_handle *trans, eb = read_tree_block(root, bytenr, blocksize, generation); btrfs_tree_lock(eb); + btrfs_set_lock_blocking(eb); } /* @@ -1610,6 +1803,7 @@ int btrfs_merge_path(struct btrfs_trans_handle *trans, eb = read_tree_block(root, bytenr, blocksize, generation); btrfs_tree_lock(eb); + btrfs_set_lock_blocking(eb); } ret = btrfs_cow_block(trans, root, eb, parent, slot, @@ -2156,6 +2350,8 @@ static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root right = read_node_slot(root, upper, slot + 1); btrfs_tree_lock(right); + btrfs_set_lock_blocking(right); + free_space = btrfs_leaf_free_space(root, right); if (free_space < data_size) goto out_unlock; @@ -2351,6 +2547,8 @@ static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root left = read_node_slot(root, path->nodes[1], slot - 1); btrfs_tree_lock(left); + btrfs_set_lock_blocking(left); + free_space = btrfs_leaf_free_space(root, left); if (free_space < data_size) { ret = 1; @@ -2809,6 +3007,12 @@ int btrfs_split_item(struct btrfs_trans_handle *trans, path->keep_locks = 0; BUG_ON(ret); + /* + * make sure any changes to the path from split_leaf leave it + * in a blocking state + */ + btrfs_set_path_blocking(path); + leaf = path->nodes[0]; BUG_ON(btrfs_leaf_free_space(root, leaf) < sizeof(struct btrfs_item)); @@ -3338,6 +3542,7 @@ int btrfs_insert_empty_items(struct btrfs_trans_handle *trans, BUG(); } out: + btrfs_unlock_up_safe(path, 1); return ret; } @@ -3705,12 +3910,14 @@ find_next_key: */ if (slot >= nritems) { path->slots[level] = slot; + btrfs_set_path_blocking(path); sret = btrfs_find_next_key(root, path, min_key, level, cache_only, min_trans); if (sret == 0) { btrfs_release_path(root, path); goto again; } else { + btrfs_clear_path_blocking(path); goto out; } } @@ -3722,16 +3929,20 @@ find_next_key: unlock_up(path, level, 1); goto out; } + btrfs_set_path_blocking(path); cur = read_node_slot(root, cur, slot); btrfs_tree_lock(cur); + path->locks[level - 1] = 1; path->nodes[level - 1] = cur; unlock_up(path, level, 1); + btrfs_clear_path_blocking(path); } out: if (ret == 0) memcpy(min_key, &found_key, sizeof(found_key)); + btrfs_set_path_blocking(path); return ret; } @@ -3827,6 +4038,7 @@ int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path) if (ret < 0) return ret; + btrfs_set_path_blocking(path); nritems = btrfs_header_nritems(path->nodes[0]); /* * by releasing the path above we dropped all our locks. A balance @@ -3857,6 +4069,7 @@ int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path) free_extent_buffer(next); } + /* the path was set to blocking above */ if (level == 1 && (path->locks[1] || path->skip_locking) && path->reada) reada_for_search(root, path, level, slot, 0); @@ -3865,6 +4078,7 @@ int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path) if (!path->skip_locking) { WARN_ON(!btrfs_tree_locked(c)); btrfs_tree_lock(next); + btrfs_set_lock_blocking(next); } break; } @@ -3881,12 +4095,15 @@ int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path) path->locks[level] = 1; if (!level) break; + + btrfs_set_path_blocking(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) { WARN_ON(!btrfs_tree_locked(path->nodes[level])); btrfs_tree_lock(next); + btrfs_set_lock_blocking(next); } } done: @@ -3911,6 +4128,7 @@ int btrfs_previous_item(struct btrfs_root *root, while (1) { if (path->slots[0] == 0) { + btrfs_set_path_blocking(path); ret = btrfs_prev_leaf(root, path); if (ret != 0) return ret; |