Btrfs: fix leaking block group on balance
The block group structs are referenced in many different
places, and it's not safe to free while balancing. So, those block
group structs were simply leaked instead.
This patch replaces the block group pointer in the inode with the starting byte
offset of the block group and adds reference counting to the block group
struct.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 673ff59..1cc8924 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -53,10 +53,6 @@
btrfs_root *extent_root, int all);
static int del_pending_extents(struct btrfs_trans_handle *trans, struct
btrfs_root *extent_root, int all);
-static struct btrfs_block_group_cache *
-__btrfs_find_block_group(struct btrfs_root *root,
- struct btrfs_block_group_cache *hint,
- u64 search_start, int data, int owner);
static int pin_down_bytes(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
u64 bytenr, u64 num_bytes, int is_data);
@@ -142,6 +138,8 @@
break;
}
}
+ if (ret)
+ atomic_inc(&ret->count);
spin_unlock(&info->block_group_cache_lock);
return ret;
@@ -318,6 +316,12 @@
return cache;
}
+static inline void put_block_group(struct btrfs_block_group_cache *cache)
+{
+ if (atomic_dec_and_test(&cache->count))
+ kfree(cache);
+}
+
static struct btrfs_space_info *__find_space_info(struct btrfs_fs_info *info,
u64 flags)
{
@@ -341,54 +345,16 @@
return num;
}
-static struct btrfs_block_group_cache *
-__btrfs_find_block_group(struct btrfs_root *root,
- struct btrfs_block_group_cache *hint,
- u64 search_start, int data, int owner)
+u64 btrfs_find_block_group(struct btrfs_root *root,
+ u64 search_start, u64 search_hint, int owner)
{
struct btrfs_block_group_cache *cache;
- struct btrfs_block_group_cache *found_group = NULL;
- struct btrfs_fs_info *info = root->fs_info;
u64 used;
- u64 last = 0;
- u64 free_check;
+ u64 last = max(search_hint, search_start);
+ u64 group_start = 0;
int full_search = 0;
- int factor = 10;
+ int factor = 9;
int wrapped = 0;
-
- if (data & BTRFS_BLOCK_GROUP_METADATA)
- factor = 9;
-
- if (search_start) {
- struct btrfs_block_group_cache *shint;
- shint = btrfs_lookup_first_block_group(info, search_start);
- if (shint && block_group_bits(shint, data)) {
- spin_lock(&shint->lock);
- used = btrfs_block_group_used(&shint->item);
- if (used + shint->pinned + shint->reserved <
- div_factor(shint->key.offset, factor)) {
- spin_unlock(&shint->lock);
- return shint;
- }
- spin_unlock(&shint->lock);
- }
- }
- if (hint && block_group_bits(hint, data)) {
- spin_lock(&hint->lock);
- used = btrfs_block_group_used(&hint->item);
- if (used + hint->pinned + hint->reserved <
- div_factor(hint->key.offset, factor)) {
- spin_unlock(&hint->lock);
- return hint;
- }
- spin_unlock(&hint->lock);
- last = hint->key.objectid + hint->key.offset;
- } else {
- if (hint)
- last = max(hint->key.objectid, search_start);
- else
- last = search_start;
- }
again:
while (1) {
cache = btrfs_lookup_first_block_group(root->fs_info, last);
@@ -399,16 +365,18 @@
last = cache->key.objectid + cache->key.offset;
used = btrfs_block_group_used(&cache->item);
- if (block_group_bits(cache, data)) {
- free_check = div_factor(cache->key.offset, factor);
+ if ((full_search || !cache->ro) &&
+ block_group_bits(cache, BTRFS_BLOCK_GROUP_METADATA)) {
if (used + cache->pinned + cache->reserved <
- free_check) {
- found_group = cache;
+ div_factor(cache->key.offset, factor)) {
+ group_start = cache->key.objectid;
spin_unlock(&cache->lock);
+ put_block_group(cache);
goto found;
}
}
spin_unlock(&cache->lock);
+ put_block_group(cache);
cond_resched();
}
if (!wrapped) {
@@ -423,18 +391,7 @@
goto again;
}
found:
- return found_group;
-}
-
-struct btrfs_block_group_cache *btrfs_find_block_group(struct btrfs_root *root,
- struct btrfs_block_group_cache
- *hint, u64 search_start,
- int data, int owner)
-{
-
- struct btrfs_block_group_cache *ret;
- ret = __btrfs_find_block_group(root, hint, search_start, data, owner);
- return ret;
+ return group_start;
}
/* simple helper to search for an existing extent at a given offset */
@@ -1809,6 +1766,19 @@
return werr;
}
+int btrfs_extent_readonly(struct btrfs_root *root, u64 bytenr)
+{
+ struct btrfs_block_group_cache *block_group;
+ int readonly = 0;
+
+ block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
+ if (!block_group || block_group->ro)
+ readonly = 1;
+ if (block_group)
+ put_block_group(block_group);
+ return readonly;
+}
+
static int update_space_info(struct btrfs_fs_info *info, u64 flags,
u64 total_bytes, u64 bytes_used,
struct btrfs_space_info **space_info)
@@ -1995,10 +1965,10 @@
int ret;
ret = btrfs_add_free_space(cache, bytenr,
num_bytes);
- if (ret)
- return -1;
+ WARN_ON(ret);
}
}
+ put_block_group(cache);
total -= num_bytes;
bytenr += num_bytes;
}
@@ -2008,12 +1978,16 @@
static u64 first_logical_byte(struct btrfs_root *root, u64 search_start)
{
struct btrfs_block_group_cache *cache;
+ u64 bytenr;
cache = btrfs_lookup_first_block_group(root->fs_info, search_start);
if (!cache)
return 0;
- return cache->key.objectid;
+ bytenr = cache->key.objectid;
+ put_block_group(cache);
+
+ return bytenr;
}
int btrfs_update_pinned_extents(struct btrfs_root *root,
@@ -2055,6 +2029,7 @@
if (cache->cached)
btrfs_add_free_space(cache, bytenr, len);
}
+ put_block_group(cache);
bytenr += len;
num -= len;
}
@@ -2085,6 +2060,7 @@
}
spin_unlock(&cache->lock);
spin_unlock(&cache->space_info->lock);
+ put_block_group(cache);
bytenr += len;
num -= len;
}
@@ -2724,6 +2700,7 @@
cache = btrfs_lookup_block_group(root->fs_info, bytenr);
BUG_ON(!cache);
btrfs_add_free_space(cache, bytenr, num_bytes);
+ put_block_group(cache);
update_reserved_extents(root, bytenr, num_bytes, 0);
return 0;
}
@@ -2928,6 +2905,8 @@
}
new_group:
mutex_unlock(&block_group->alloc_mutex);
+ put_block_group(block_group);
+ block_group = NULL;
new_group_no_lock:
/* don't try to compare new allocations against the
* last allocation any more
@@ -2997,6 +2976,8 @@
block_group = list_entry(cur, struct btrfs_block_group_cache,
list);
+ atomic_inc(&block_group->count);
+
search_start = block_group->key.objectid;
cur = cur->next;
}
@@ -3004,7 +2985,7 @@
/* we found what we needed */
if (ins->objectid) {
if (!(data & BTRFS_BLOCK_GROUP_DATA))
- trans->block_group = block_group;
+ trans->block_group = block_group->key.objectid;
if (last_ptr)
*last_ptr = ins->objectid + ins->offset;
@@ -3015,6 +2996,8 @@
loop, allowed_chunk_alloc);
ret = -ENOSPC;
}
+ if (block_group)
+ put_block_group(block_group);
up_read(&space_info->groups_sem);
return ret;
@@ -3124,6 +3107,7 @@
return -ENOSPC;
}
btrfs_add_free_space(cache, start, len);
+ put_block_group(cache);
update_reserved_extents(root, start, len, 0);
return 0;
}
@@ -3288,6 +3272,7 @@
ret = btrfs_remove_free_space(block_group, ins->objectid,
ins->offset);
BUG_ON(ret);
+ put_block_group(block_group);
ret = __btrfs_alloc_reserved_extent(trans, root, parent, root_objectid,
ref_generation, owner, ins);
return ret;
@@ -5703,6 +5688,7 @@
WARN_ON(block_group->reserved > 0);
WARN_ON(btrfs_block_group_used(&block_group->item) > 0);
spin_unlock(&block_group->lock);
+ put_block_group(block_group);
ret = 0;
out:
btrfs_free_path(path);
@@ -5763,6 +5749,8 @@
down_write(&block_group->space_info->groups_sem);
list_del(&block_group->list);
up_write(&block_group->space_info->groups_sem);
+
+ WARN_ON(atomic_read(&block_group->count) != 1);
kfree(block_group);
spin_lock(&info->block_group_cache_lock);
@@ -5807,6 +5795,7 @@
break;
}
+ atomic_set(&cache->count, 1);
spin_lock_init(&cache->lock);
mutex_init(&cache->alloc_mutex);
mutex_init(&cache->cache_mutex);
@@ -5861,11 +5850,12 @@
cache->key.objectid = chunk_offset;
cache->key.offset = size;
+ cache->key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
+ atomic_set(&cache->count, 1);
spin_lock_init(&cache->lock);
mutex_init(&cache->alloc_mutex);
mutex_init(&cache->cache_mutex);
INIT_LIST_HEAD(&cache->list);
- btrfs_set_key_type(&cache->key, BTRFS_BLOCK_GROUP_ITEM_KEY);
btrfs_set_block_group_used(&cache->item, bytes_used);
btrfs_set_block_group_chunk_objectid(&cache->item, chunk_objectid);
@@ -5926,10 +5916,8 @@
spin_unlock(&block_group->space_info->lock);
block_group->space_info->full = 0;
- /*
- memset(shrink_block_group, 0, sizeof(*shrink_block_group));
- kfree(shrink_block_group);
- */
+ put_block_group(block_group);
+ put_block_group(block_group);
ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
if (ret > 0)