diff options
Diffstat (limited to 'fs/btrfs/ctree.c')
| -rw-r--r-- | fs/btrfs/ctree.c | 27 |
1 files changed, 22 insertions, 5 deletions
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c index 011cab3..dede441 100644 --- a/fs/btrfs/ctree.c +++ b/fs/btrfs/ctree.c @@ -514,10 +514,25 @@ static inline int should_cow_block(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct extent_buffer *buf) { + /* ensure we can see the force_cow */ + smp_rmb(); + + /* + * We do not need to cow a block if + * 1) this block is not created or changed in this transaction; + * 2) this block does not belong to TREE_RELOC tree; + * 3) the root is not forced COW. + * + * What is forced COW: + * when we create snapshot during commiting the transaction, + * after we've finished coping src root, we must COW the shared + * block to ensure the metadata consistency. + */ if (btrfs_header_generation(buf) == trans->transid && !btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN) && !(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID && - btrfs_header_flag(buf, BTRFS_HEADER_FLAG_RELOC))) + btrfs_header_flag(buf, BTRFS_HEADER_FLAG_RELOC)) && + !root->force_cow) return 0; return 1; } @@ -902,9 +917,10 @@ static noinline int balance_level(struct btrfs_trans_handle *trans, orig_ptr = btrfs_node_blockptr(mid, orig_slot); - if (level < BTRFS_MAX_LEVEL - 1) + if (level < BTRFS_MAX_LEVEL - 1) { parent = path->nodes[level + 1]; - pslot = path->slots[level + 1]; + pslot = path->slots[level + 1]; + } /* * deal with the case where there is only one pointer in the root @@ -1107,9 +1123,10 @@ static noinline int push_nodes_for_insert(struct btrfs_trans_handle *trans, mid = path->nodes[level]; WARN_ON(btrfs_header_generation(mid) != trans->transid); - if (level < BTRFS_MAX_LEVEL - 1) + if (level < BTRFS_MAX_LEVEL - 1) { parent = path->nodes[level + 1]; - pslot = path->slots[level + 1]; + pslot = path->slots[level + 1]; + } if (!parent) return 1; |
