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| author | Chris Mason <chris.mason@oracle.com> | 2007-08-07 15:52:19 -0400 |
|---|---|---|
| committer | David Woodhouse <dwmw2@hera.kernel.org> | 2007-08-07 15:52:19 -0400 |
| commit | 9f3a742736cecda5a8778be70faa2f779458839f (patch) | |
| tree | 500ef3701521e63254dbe82e5c71e7ccff746275 /fs/btrfs/ctree.c | |
| parent | 8578f0f1fda41f8429a1037022b720275102ca65 (diff) | |
| download | lwn-9f3a742736cecda5a8778be70faa2f779458839f.tar.gz lwn-9f3a742736cecda5a8778be70faa2f779458839f.zip | |
Btrfs: Do snapshot deletion in smaller chunks.
Before, snapshot deletion was a single atomic unit. This caused considerable
lock contention and required an unbounded amount of space. Now,
the drop_progress field in the root item is used to indicate how far along
snapshot deletion is, and to resume where it left off.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Diffstat (limited to 'fs/btrfs/ctree.c')
| -rw-r--r-- | fs/btrfs/ctree.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c index 19a30b7c3a28..aa824e2c521f 100644 --- a/fs/btrfs/ctree.c +++ b/fs/btrfs/ctree.c @@ -659,9 +659,16 @@ int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root struct buffer_head *b; struct buffer_head *cow_buf; struct btrfs_node *c; + struct btrfs_root_item *root_item = &root->root_item; int slot; int ret; int level; + u8 lowest_level = 0; + + if (btrfs_root_refs(root_item) == 0 && root->ref_cows) { + lowest_level = root_item->drop_level; + WARN_ON(ins_len || cow); + } WARN_ON(p->nodes[0] != NULL); WARN_ON(!mutex_is_locked(&root->fs_info->fs_mutex)); @@ -718,6 +725,9 @@ again: slot = p->slots[level]; BUG_ON(btrfs_header_nritems(&c->header) == 1); } + /* this is only true while dropping a snapshot */ + if (level == lowest_level) + break; b = read_tree_block(root, btrfs_node_blockptr(c, slot)); } else { struct btrfs_leaf *l = (struct btrfs_leaf *)c; |