From a826d6dcb32d811b4c81df57a5ef1367516586b0 Mon Sep 17 00:00:00 2001 From: Josef Bacik Date: Wed, 16 Mar 2011 13:42:43 -0400 Subject: Btrfs: check items for correctness as we search Currently if we have corrupted items things will blow up in spectacular ways. So as we read in blocks and they are leaves, check the entire leaf to make sure all of the items are correct and point to valid parts in the leaf for the item data the are responsible for. If the item is corrupt we will kick back EIO and not read any of the copies since they are likely to not be correct either. This will catch generic corruptions, it will be up to the individual callers of btrfs_search_slot to make sure their items are right. Thanks, Signed-off-by: Josef Bacik --- fs/btrfs/ctree.c | 123 ------------------------------------------------------- 1 file changed, 123 deletions(-) (limited to 'fs/btrfs/ctree.c') diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c index b5baff0dccfe..73e53009e126 100644 --- a/fs/btrfs/ctree.c +++ b/fs/btrfs/ctree.c @@ -732,122 +732,6 @@ static inline unsigned int leaf_data_end(struct btrfs_root *root, return btrfs_item_offset_nr(leaf, nr - 1); } -/* - * extra debugging checks to make sure all the items in a key are - * well formed and in the proper order - */ -static int check_node(struct btrfs_root *root, struct btrfs_path *path, - int level) -{ - struct extent_buffer *parent = NULL; - struct extent_buffer *node = path->nodes[level]; - struct btrfs_disk_key parent_key; - struct btrfs_disk_key node_key; - int parent_slot; - int slot; - struct btrfs_key cpukey; - u32 nritems = btrfs_header_nritems(node); - - if (path->nodes[level + 1]) - parent = path->nodes[level + 1]; - - slot = path->slots[level]; - BUG_ON(nritems == 0); - if (parent) { - parent_slot = path->slots[level + 1]; - btrfs_node_key(parent, &parent_key, parent_slot); - btrfs_node_key(node, &node_key, 0); - BUG_ON(memcmp(&parent_key, &node_key, - sizeof(struct btrfs_disk_key))); - BUG_ON(btrfs_node_blockptr(parent, parent_slot) != - btrfs_header_bytenr(node)); - } - BUG_ON(nritems > BTRFS_NODEPTRS_PER_BLOCK(root)); - if (slot != 0) { - btrfs_node_key_to_cpu(node, &cpukey, slot - 1); - btrfs_node_key(node, &node_key, slot); - BUG_ON(comp_keys(&node_key, &cpukey) <= 0); - } - if (slot < nritems - 1) { - btrfs_node_key_to_cpu(node, &cpukey, slot + 1); - btrfs_node_key(node, &node_key, slot); - BUG_ON(comp_keys(&node_key, &cpukey) >= 0); - } - return 0; -} - -/* - * extra checking to make sure all the items in a leaf are - * well formed and in the proper order - */ -static int check_leaf(struct btrfs_root *root, struct btrfs_path *path, - int level) -{ - struct extent_buffer *leaf = path->nodes[level]; - struct extent_buffer *parent = NULL; - int parent_slot; - struct btrfs_key cpukey; - struct btrfs_disk_key parent_key; - struct btrfs_disk_key leaf_key; - int slot = path->slots[0]; - - u32 nritems = btrfs_header_nritems(leaf); - - if (path->nodes[level + 1]) - parent = path->nodes[level + 1]; - - if (nritems == 0) - return 0; - - if (parent) { - parent_slot = path->slots[level + 1]; - btrfs_node_key(parent, &parent_key, parent_slot); - btrfs_item_key(leaf, &leaf_key, 0); - - BUG_ON(memcmp(&parent_key, &leaf_key, - sizeof(struct btrfs_disk_key))); - BUG_ON(btrfs_node_blockptr(parent, parent_slot) != - btrfs_header_bytenr(leaf)); - } - if (slot != 0 && slot < nritems - 1) { - btrfs_item_key(leaf, &leaf_key, slot); - btrfs_item_key_to_cpu(leaf, &cpukey, slot - 1); - if (comp_keys(&leaf_key, &cpukey) <= 0) { - btrfs_print_leaf(root, leaf); - printk(KERN_CRIT "slot %d offset bad key\n", slot); - BUG_ON(1); - } - if (btrfs_item_offset_nr(leaf, slot - 1) != - btrfs_item_end_nr(leaf, slot)) { - btrfs_print_leaf(root, leaf); - printk(KERN_CRIT "slot %d offset bad\n", slot); - BUG_ON(1); - } - } - if (slot < nritems - 1) { - btrfs_item_key(leaf, &leaf_key, slot); - btrfs_item_key_to_cpu(leaf, &cpukey, slot + 1); - BUG_ON(comp_keys(&leaf_key, &cpukey) >= 0); - if (btrfs_item_offset_nr(leaf, slot) != - btrfs_item_end_nr(leaf, slot + 1)) { - btrfs_print_leaf(root, leaf); - printk(KERN_CRIT "slot %d offset bad\n", slot); - BUG_ON(1); - } - } - BUG_ON(btrfs_item_offset_nr(leaf, 0) + - btrfs_item_size_nr(leaf, 0) != BTRFS_LEAF_DATA_SIZE(root)); - return 0; -} - -static noinline int check_block(struct btrfs_root *root, - struct btrfs_path *path, int level) -{ - return 0; - if (level == 0) - return check_leaf(root, path, level); - return check_node(root, path, level); -} /* * search for key in the extent_buffer. The items start at offset p, @@ -1188,7 +1072,6 @@ static noinline int balance_level(struct btrfs_trans_handle *trans, } } /* double check we haven't messed things up */ - check_block(root, path, level); if (orig_ptr != btrfs_node_blockptr(path->nodes[level], path->slots[level])) BUG(); @@ -1798,12 +1681,6 @@ cow_done: if (!cow) btrfs_unlock_up_safe(p, level + 1); - ret = check_block(root, p, level); - if (ret) { - ret = -1; - goto done; - } - ret = bin_search(b, key, level, &slot); if (level != 0) { -- cgit v1.2.3 From 240f62c8756df285da11469259b3900f32883168 Mon Sep 17 00:00:00 2001 From: Chris Mason Date: Wed, 23 Mar 2011 14:54:42 -0400 Subject: Btrfs: use RCU instead of a spinlock to protect the root node The pointer to the extent buffer for the root of each tree is protected by a spinlock so that we can safely read the pointer and take a reference on the extent buffer. But now that the extent buffers are freed via RCU, we can safely use rcu_read_lock instead. Signed-off-by: Chris Mason --- fs/btrfs/ctree.c | 27 ++++++++------------------- 1 file changed, 8 insertions(+), 19 deletions(-) (limited to 'fs/btrfs/ctree.c') diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c index 73e53009e126..8680110f0a5a 100644 --- a/fs/btrfs/ctree.c +++ b/fs/btrfs/ctree.c @@ -147,10 +147,11 @@ noinline void btrfs_release_path(struct btrfs_root *root, struct btrfs_path *p) struct extent_buffer *btrfs_root_node(struct btrfs_root *root) { struct extent_buffer *eb; - spin_lock(&root->node_lock); - eb = root->node; + + rcu_read_lock(); + eb = rcu_dereference(root->node); extent_buffer_get(eb); - spin_unlock(&root->node_lock); + rcu_read_unlock(); return eb; } @@ -165,14 +166,8 @@ struct extent_buffer *btrfs_lock_root_node(struct btrfs_root *root) while (1) { eb = btrfs_root_node(root); btrfs_tree_lock(eb); - - spin_lock(&root->node_lock); - if (eb == root->node) { - spin_unlock(&root->node_lock); + if (eb == root->node) break; - } - spin_unlock(&root->node_lock); - btrfs_tree_unlock(eb); free_extent_buffer(eb); } @@ -458,10 +453,8 @@ static noinline int __btrfs_cow_block(struct btrfs_trans_handle *trans, else parent_start = 0; - spin_lock(&root->node_lock); - root->node = cow; extent_buffer_get(cow); - spin_unlock(&root->node_lock); + rcu_assign_pointer(root->node, cow); btrfs_free_tree_block(trans, root, buf, parent_start, last_ref); @@ -930,9 +923,7 @@ static noinline int balance_level(struct btrfs_trans_handle *trans, goto enospc; } - spin_lock(&root->node_lock); - root->node = child; - spin_unlock(&root->node_lock); + rcu_assign_pointer(root->node, child); add_root_to_dirty_list(root); btrfs_tree_unlock(child); @@ -2007,10 +1998,8 @@ static noinline int insert_new_root(struct btrfs_trans_handle *trans, btrfs_mark_buffer_dirty(c); - spin_lock(&root->node_lock); old = root->node; - root->node = c; - spin_unlock(&root->node_lock); + rcu_assign_pointer(root->node, c); /* the super has an extra ref to root->node */ free_extent_buffer(old); -- cgit v1.2.3 From 1abe9b8a138c9988ba8f7bfded6453649a31541f Mon Sep 17 00:00:00 2001 From: liubo Date: Thu, 24 Mar 2011 11:18:59 +0000 Subject: Btrfs: add initial tracepoint support for btrfs Tracepoints can provide insight into why btrfs hits bugs and be greatly helpful for debugging, e.g dd-7822 [000] 2121.641088: btrfs_inode_request: root = 5(FS_TREE), gen = 4, ino = 256, blocks = 8, disk_i_size = 0, last_trans = 8, logged_trans = 0 dd-7822 [000] 2121.641100: btrfs_inode_new: root = 5(FS_TREE), gen = 8, ino = 257, blocks = 0, disk_i_size = 0, last_trans = 0, logged_trans = 0 btrfs-transacti-7804 [001] 2146.935420: btrfs_cow_block: root = 2(EXTENT_TREE), refs = 2, orig_buf = 29368320 (orig_level = 0), cow_buf = 29388800 (cow_level = 0) btrfs-transacti-7804 [001] 2146.935473: btrfs_cow_block: root = 1(ROOT_TREE), refs = 2, orig_buf = 29364224 (orig_level = 0), cow_buf = 29392896 (cow_level = 0) btrfs-transacti-7804 [001] 2146.972221: btrfs_transaction_commit: root = 1(ROOT_TREE), gen = 8 flush-btrfs-2-7821 [001] 2155.824210: btrfs_chunk_alloc: root = 3(CHUNK_TREE), offset = 1103101952, size = 1073741824, num_stripes = 1, sub_stripes = 0, type = DATA flush-btrfs-2-7821 [001] 2155.824241: btrfs_cow_block: root = 2(EXTENT_TREE), refs = 2, orig_buf = 29388800 (orig_level = 0), cow_buf = 29396992 (cow_level = 0) flush-btrfs-2-7821 [001] 2155.824255: btrfs_cow_block: root = 4(DEV_TREE), refs = 2, orig_buf = 29372416 (orig_level = 0), cow_buf = 29401088 (cow_level = 0) flush-btrfs-2-7821 [000] 2155.824329: btrfs_cow_block: root = 3(CHUNK_TREE), refs = 2, orig_buf = 20971520 (orig_level = 0), cow_buf = 20975616 (cow_level = 0) btrfs-endio-wri-7800 [001] 2155.898019: btrfs_cow_block: root = 5(FS_TREE), refs = 2, orig_buf = 29384704 (orig_level = 0), cow_buf = 29405184 (cow_level = 0) btrfs-endio-wri-7800 [001] 2155.898043: btrfs_cow_block: root = 7(CSUM_TREE), refs = 2, orig_buf = 29376512 (orig_level = 0), cow_buf = 29409280 (cow_level = 0) Here is what I have added: 1) ordere_extent: btrfs_ordered_extent_add btrfs_ordered_extent_remove btrfs_ordered_extent_start btrfs_ordered_extent_put These provide critical information to understand how ordered_extents are updated. 2) extent_map: btrfs_get_extent extent_map is used in both read and write cases, and it is useful for tracking how btrfs specific IO is running. 3) writepage: __extent_writepage btrfs_writepage_end_io_hook Pages are cirtical resourses and produce a lot of corner cases during writeback, so it is valuable to know how page is written to disk. 4) inode: btrfs_inode_new btrfs_inode_request btrfs_inode_evict These can show where and when a inode is created, when a inode is evicted. 5) sync: btrfs_sync_file btrfs_sync_fs These show sync arguments. 6) transaction: btrfs_transaction_commit In transaction based filesystem, it will be useful to know the generation and who does commit. 7) back reference and cow: btrfs_delayed_tree_ref btrfs_delayed_data_ref btrfs_delayed_ref_head btrfs_cow_block Btrfs natively supports back references, these tracepoints are helpful on understanding btrfs's COW mechanism. 8) chunk: btrfs_chunk_alloc btrfs_chunk_free Chunk is a link between physical offset and logical offset, and stands for space infomation in btrfs, and these are helpful on tracing space things. 9) reserved_extent: btrfs_reserved_extent_alloc btrfs_reserved_extent_free These can show how btrfs uses its space. Signed-off-by: Liu Bo Signed-off-by: Chris Mason --- fs/btrfs/ctree.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'fs/btrfs/ctree.c') diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c index 8680110f0a5a..465b5d7d6b48 100644 --- a/fs/btrfs/ctree.c +++ b/fs/btrfs/ctree.c @@ -535,6 +535,9 @@ noinline int btrfs_cow_block(struct btrfs_trans_handle *trans, ret = __btrfs_cow_block(trans, root, buf, parent, parent_slot, cow_ret, search_start, 0); + + trace_btrfs_cow_block(root, buf, *cow_ret); + return ret; } -- cgit v1.2.3 From db5b493ac78e46c7b6bad22cd25d8041564cd8ea Mon Sep 17 00:00:00 2001 From: Tsutomu Itoh Date: Wed, 23 Mar 2011 08:14:16 +0000 Subject: Btrfs: cleanup some BUG_ON() This patch changes some BUG_ON() to the error return. (but, most callers still use BUG_ON()) Signed-off-by: Tsutomu Itoh Signed-off-by: Chris Mason --- fs/btrfs/ctree.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'fs/btrfs/ctree.c') diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c index 465b5d7d6b48..4edcbe915736 100644 --- a/fs/btrfs/ctree.c +++ b/fs/btrfs/ctree.c @@ -3709,7 +3709,8 @@ int btrfs_insert_item(struct btrfs_trans_handle *trans, struct btrfs_root unsigned long ptr; path = btrfs_alloc_path(); - BUG_ON(!path); + if (!path) + return -ENOMEM; ret = btrfs_insert_empty_item(trans, root, path, cpu_key, data_size); if (!ret) { leaf = path->nodes[0]; -- cgit v1.2.3 From 97d9a8a420444eb5b5c071d4b3b9c4100a7ae015 Mon Sep 17 00:00:00 2001 From: Tsutomu Itoh Date: Thu, 24 Mar 2011 06:33:21 +0000 Subject: Btrfs: check return value of read_tree_block() This patch is checking return value of read_tree_block(), and if it is NULL, error processing. Signed-off-by: Tsutomu Itoh Signed-off-by: Chris Mason --- fs/btrfs/ctree.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'fs/btrfs/ctree.c') diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c index 4edcbe915736..84d7ca1fe0ba 100644 --- a/fs/btrfs/ctree.c +++ b/fs/btrfs/ctree.c @@ -682,6 +682,8 @@ int btrfs_realloc_node(struct btrfs_trans_handle *trans, if (!cur) { cur = read_tree_block(root, blocknr, blocksize, gen); + if (!cur) + return -EIO; } else if (!uptodate) { btrfs_read_buffer(cur, gen); } @@ -4087,6 +4089,7 @@ find_next_key: } btrfs_set_path_blocking(path); cur = read_node_slot(root, cur, slot); + BUG_ON(!cur); btrfs_tree_lock(cur); -- cgit v1.2.3