diff options
Diffstat (limited to 'fs/btrfs/ctree.c')
| -rw-r--r-- | fs/btrfs/ctree.c | 36 |
1 files changed, 30 insertions, 6 deletions
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c index a9543f01184c..dcb510f38dda 100644 --- a/fs/btrfs/ctree.c +++ b/fs/btrfs/ctree.c @@ -4663,7 +4663,12 @@ int btrfs_next_old_leaf(struct btrfs_root *root, struct btrfs_path *path, int ret; int i; - ASSERT(!path->nowait); + /* + * The nowait semantics are used only for write paths, where we don't + * use the tree mod log and sequence numbers. + */ + if (time_seq) + ASSERT(!path->nowait); nritems = btrfs_header_nritems(path->nodes[0]); if (nritems == 0) @@ -4683,7 +4688,14 @@ again: if (path->need_commit_sem) { path->need_commit_sem = 0; need_commit_sem = true; - down_read(&fs_info->commit_root_sem); + if (path->nowait) { + if (!down_read_trylock(&fs_info->commit_root_sem)) { + ret = -EAGAIN; + goto done; + } + } else { + down_read(&fs_info->commit_root_sem); + } } ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); } @@ -4759,7 +4771,7 @@ again: next = c; ret = read_block_for_search(root, path, &next, level, slot, &key); - if (ret == -EAGAIN) + if (ret == -EAGAIN && !path->nowait) goto again; if (ret < 0) { @@ -4769,6 +4781,10 @@ again: if (!path->skip_locking) { ret = btrfs_try_tree_read_lock(next); + if (!ret && path->nowait) { + ret = -EAGAIN; + goto done; + } if (!ret && time_seq) { /* * If we don't get the lock, we may be racing @@ -4799,7 +4815,7 @@ again: ret = read_block_for_search(root, path, &next, level, 0, &key); - if (ret == -EAGAIN) + if (ret == -EAGAIN && !path->nowait) goto again; if (ret < 0) { @@ -4807,8 +4823,16 @@ again: goto done; } - if (!path->skip_locking) - btrfs_tree_read_lock(next); + if (!path->skip_locking) { + if (path->nowait) { + if (!btrfs_try_tree_read_lock(next)) { + ret = -EAGAIN; + goto done; + } + } else { + btrfs_tree_read_lock(next); + } + } } ret = 0; done: |