Btrfs: Add locking around volume management (device add/remove/balance)
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 5e0857f..8ebfa6b 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -245,6 +245,7 @@
u64 search_start = *start_ret;
int wrapped = 0;
+ WARN_ON(!mutex_is_locked(&root->fs_info->alloc_mutex));
total_fs_bytes = btrfs_super_total_bytes(&root->fs_info->super_copy);
free_space_cache = &root->fs_info->free_space_cache;
@@ -1242,6 +1243,7 @@
u64 start;
u64 end;
+ WARN_ON(!mutex_is_locked(&root->fs_info->alloc_mutex));
while(total) {
cache = btrfs_lookup_block_group(info, bytenr);
if (!cache) {
@@ -1297,6 +1299,7 @@
struct btrfs_block_group_cache *cache;
struct btrfs_fs_info *fs_info = root->fs_info;
+ WARN_ON(!mutex_is_locked(&root->fs_info->alloc_mutex));
if (pin) {
set_extent_dirty(&fs_info->pinned_extents,
bytenr, bytenr + num - 1, GFP_NOFS);
@@ -1391,6 +1394,7 @@
int level;
int err = 0;
+ WARN_ON(!mutex_is_locked(&extent_root->fs_info->alloc_mutex));
btrfs_set_stack_extent_refs(&extent_item, 1);
btrfs_set_key_type(&ins, BTRFS_EXTENT_ITEM_KEY);
path = btrfs_alloc_path();
@@ -1437,6 +1441,7 @@
{
int err = 0;
+ WARN_ON(!mutex_is_locked(&root->fs_info->alloc_mutex));
if (!pending) {
struct extent_buffer *buf;
buf = btrfs_find_tree_block(root, bytenr, num_bytes);
@@ -1490,6 +1495,7 @@
struct btrfs_extent_item *ei;
u32 refs;
+ WARN_ON(!mutex_is_locked(&root->fs_info->alloc_mutex));
key.objectid = bytenr;
btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
key.offset = num_bytes;
@@ -1619,6 +1625,7 @@
struct extent_io_tree *pending_del;
struct extent_io_tree *pinned_extents;
+ WARN_ON(!mutex_is_locked(&extent_root->fs_info->alloc_mutex));
pending_del = &extent_root->fs_info->pending_del;
pinned_extents = &extent_root->fs_info->pinned_extents;
@@ -2428,6 +2435,10 @@
btrfs_node_key(node, &found_key, path->slots[level]);
WARN_ON(memcmp(&found_key, &root_item->drop_progress,
sizeof(found_key)));
+ /*
+ * unlock our path, this is safe because only this
+ * function is allowed to delete this snapshot
+ */
for (i = 0; i < BTRFS_MAX_LEVEL; i++) {
if (path->nodes[i] && path->locks[i]) {
path->locks[i] = 0;
@@ -2611,7 +2622,6 @@
u64 root_search_start = BTRFS_FS_TREE_OBJECTID;
u64 found_bytenr;
int ret;
- int i;
root_location.offset = (u64)-1;
root_location.type = BTRFS_ROOT_ITEM_KEY;
@@ -2635,12 +2645,6 @@
found_bytenr = path->nodes[level]->start;
}
- for (i = level; i < BTRFS_MAX_LEVEL; i++) {
- if (!path->nodes[i])
- break;
- free_extent_buffer(path->nodes[i]);
- path->nodes[i] = NULL;
- }
btrfs_release_path(cur_root, path);
if (found_bytenr == bytenr) {
@@ -2689,6 +2693,8 @@
int ret;
int level;
+ WARN_ON(!mutex_is_locked(&extent_root->fs_info->alloc_mutex));
+
ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
struct btrfs_extent_ref);
ref_root = btrfs_ref_root(path->nodes[0], ref);
@@ -2707,6 +2713,7 @@
found_root = btrfs_read_fs_root_no_name(extent_root->fs_info,
&root_location);
BUG_ON(!found_root);
+ mutex_unlock(&extent_root->fs_info->alloc_mutex);
if (ref_objectid >= BTRFS_FIRST_FREE_OBJECTID) {
found_key.objectid = ref_objectid;
@@ -2748,9 +2755,9 @@
/* this can happen if the reference is not against
* the latest version of the tree root
*/
- if (is_bad_inode(inode)) {
+ if (is_bad_inode(inode))
goto out;
- }
+
*last_file_objectid = inode->i_ino;
*last_file_root = found_root->root_key.objectid;
*last_file_offset = ref_offset;
@@ -2760,7 +2767,7 @@
} else {
struct btrfs_trans_handle *trans;
struct extent_buffer *eb;
- int i;
+ int needs_lock = 0;
eb = read_tree_block(found_root, extent_key->objectid,
extent_key->offset, 0);
@@ -2782,26 +2789,40 @@
if (ret)
goto out;
+ /*
+ * right here almost anything could happen to our key,
+ * but that's ok. The cow below will either relocate it
+ * or someone else will have relocated it. Either way,
+ * it is in a different spot than it was before and
+ * we're happy.
+ */
+
trans = btrfs_start_transaction(found_root, 1);
+ if (found_root == extent_root->fs_info->extent_root ||
+ found_root == extent_root->fs_info->chunk_root ||
+ found_root == extent_root->fs_info->dev_root) {
+ needs_lock = 1;
+ mutex_lock(&extent_root->fs_info->alloc_mutex);
+ }
+
path->lowest_level = level;
path->reada = 2;
ret = btrfs_search_slot(trans, found_root, &found_key, path,
0, 1);
path->lowest_level = 0;
- for (i = level; i < BTRFS_MAX_LEVEL; i++) {
- if (!path->nodes[i])
- break;
- free_extent_buffer(path->nodes[i]);
- path->nodes[i] = NULL;
- }
btrfs_release_path(found_root, path);
+
if (found_root == found_root->fs_info->extent_root)
btrfs_extent_post_op(trans, found_root);
- btrfs_end_transaction(trans, found_root);
- }
+ if (needs_lock)
+ mutex_unlock(&extent_root->fs_info->alloc_mutex);
+ btrfs_end_transaction(trans, found_root);
+
+ }
out:
+ mutex_lock(&extent_root->fs_info->alloc_mutex);
return 0;
}
@@ -2943,7 +2964,10 @@
if (btrfs_block_group_used(&shrink_block_group->item) > 0) {
+ mutex_unlock(&root->fs_info->alloc_mutex);
trans = btrfs_start_transaction(root, 1);
+ mutex_lock(&root->fs_info->alloc_mutex);
+
new_alloc_flags = update_block_group_flags(root,
shrink_block_group->flags);
if (new_alloc_flags != shrink_block_group->flags) {
@@ -2954,7 +2978,10 @@
}
do_chunk_alloc(trans, root->fs_info->extent_root,
calc + 2 * 1024 * 1024, new_alloc_flags, force);
+
+ mutex_unlock(&root->fs_info->alloc_mutex);
btrfs_end_transaction(trans, root);
+ mutex_lock(&root->fs_info->alloc_mutex);
}
return 0;
}
@@ -3031,9 +3058,9 @@
if (ret < 0)
goto out;
+next:
leaf = path->nodes[0];
nritems = btrfs_header_nritems(leaf);
-next:
if (path->slots[0] >= nritems) {
ret = btrfs_next_leaf(root, path);
if (ret < 0)
@@ -3083,6 +3110,7 @@
printk("btrfs relocate found %llu last extent was %llu\n",
(unsigned long long)total_found,
(unsigned long long)found_key.objectid);
+ mutex_unlock(&root->fs_info->alloc_mutex);
trans = btrfs_start_transaction(tree_root, 1);
btrfs_commit_transaction(trans, tree_root);
@@ -3090,6 +3118,7 @@
trans = btrfs_start_transaction(tree_root, 1);
btrfs_commit_transaction(trans, tree_root);
+ mutex_lock(&root->fs_info->alloc_mutex);
goto again;
}
@@ -3097,7 +3126,10 @@
* we've freed all the extents, now remove the block
* group item from the tree
*/
+ mutex_unlock(&root->fs_info->alloc_mutex);
+
trans = btrfs_start_transaction(root, 1);
+ mutex_lock(&root->fs_info->alloc_mutex);
memcpy(&key, &shrink_block_group->key, sizeof(key));
ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
@@ -3119,8 +3151,12 @@
kfree(shrink_block_group);
btrfs_del_item(trans, root, path);
+ btrfs_release_path(root, path);
+ mutex_unlock(&root->fs_info->alloc_mutex);
btrfs_commit_transaction(trans, root);
+ mutex_lock(&root->fs_info->alloc_mutex);
+
/* the code to unpin extents might set a few bits in the free
* space cache for this range again
*/
@@ -3263,6 +3299,7 @@
struct btrfs_block_group_cache *cache;
struct extent_io_tree *block_group_cache;
+ WARN_ON(!mutex_is_locked(&root->fs_info->alloc_mutex));
extent_root = root->fs_info->extent_root;
block_group_cache = &root->fs_info->block_group_cache;