diff options
| -rw-r--r-- | fs/btrfs/extent_map.c | 72 |
1 files changed, 41 insertions, 31 deletions
diff --git a/fs/btrfs/extent_map.c b/fs/btrfs/extent_map.c index a4a7a1a8da95..b60955d4f9bf 100644 --- a/fs/btrfs/extent_map.c +++ b/fs/btrfs/extent_map.c @@ -79,12 +79,21 @@ void free_extent_map(struct extent_map *em) } } -static struct rb_node *tree_insert(struct rb_root *root, u64 offset, - struct rb_node *node) +/* simple helper to do math around the end of an extent, handling wrap */ +static u64 range_end(u64 start, u64 len) +{ + if (start + len < start) + return (u64)-1; + return start + len; +} + +static int tree_insert(struct rb_root *root, struct extent_map *em) { struct rb_node **p = &root->rb_node; struct rb_node *parent = NULL; - struct extent_map *entry; + struct extent_map *entry = NULL; + struct rb_node *orig_parent = NULL; + u64 end = range_end(em->start, em->len); while (*p) { parent = *p; @@ -92,19 +101,37 @@ static struct rb_node *tree_insert(struct rb_root *root, u64 offset, WARN_ON(!entry->in_tree); - if (offset < entry->start) + if (em->start < entry->start) p = &(*p)->rb_left; - else if (offset >= extent_map_end(entry)) + else if (em->start >= extent_map_end(entry)) p = &(*p)->rb_right; else - return parent; + return -EEXIST; } - entry = rb_entry(node, struct extent_map, rb_node); - entry->in_tree = 1; - rb_link_node(node, parent, p); - rb_insert_color(node, root); - return NULL; + orig_parent = parent; + while (parent && em->start >= extent_map_end(entry)) { + parent = rb_next(parent); + entry = rb_entry(parent, struct extent_map, rb_node); + } + if (parent) + if (end > entry->start && em->start < extent_map_end(entry)) + return -EEXIST; + + parent = orig_parent; + entry = rb_entry(parent, struct extent_map, rb_node); + while (parent && em->start < entry->start) { + parent = rb_prev(parent); + entry = rb_entry(parent, struct extent_map, rb_node); + } + if (parent) + if (end > entry->start && em->start < extent_map_end(entry)) + return -EEXIST; + + em->in_tree = 1; + rb_link_node(&em->rb_node, orig_parent, p); + rb_insert_color(&em->rb_node, root); + return 0; } /* @@ -310,20 +337,11 @@ int add_extent_mapping(struct extent_map_tree *tree, struct extent_map *em, int modified) { int ret = 0; - struct rb_node *rb; - struct extent_map *exist; - exist = lookup_extent_mapping(tree, em->start, em->len); - if (exist) { - free_extent_map(exist); - ret = -EEXIST; - goto out; - } - rb = tree_insert(&tree->map, em->start, &em->rb_node); - if (rb) { - ret = -EEXIST; + ret = tree_insert(&tree->map, em); + if (ret) goto out; - } + atomic_inc(&em->refs); em->mod_start = em->start; @@ -337,14 +355,6 @@ out: return ret; } -/* simple helper to do math around the end of an extent, handling wrap */ -static u64 range_end(u64 start, u64 len) -{ - if (start + len < start) - return (u64)-1; - return start + len; -} - static struct extent_map * __lookup_extent_mapping(struct extent_map_tree *tree, u64 start, u64 len, int strict) |