Btrfs: Replace the big fs_mutex with a collection of other locks
Extent alloctions are still protected by a large alloc_mutex.
Objectid allocations are covered by a objectid mutex
Other btree operations are protected by a lock on individual btree nodes
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index fe40bdd..f638803 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -724,6 +724,7 @@
INIT_LIST_HEAD(&root->dirty_list);
spin_lock_init(&root->node_lock);
+ mutex_init(&root->objectid_mutex);
memset(&root->root_key, 0, sizeof(root->root_key));
memset(&root->root_item, 0, sizeof(root->root_item));
memset(&root->defrag_progress, 0, sizeof(root->defrag_progress));
@@ -1146,6 +1147,7 @@
INIT_LIST_HEAD(&fs_info->space_info);
btrfs_mapping_init(&fs_info->mapping_tree);
atomic_set(&fs_info->nr_async_submits, 0);
+ atomic_set(&fs_info->throttles, 0);
fs_info->sb = sb;
fs_info->max_extent = (u64)-1;
fs_info->max_inline = 8192 * 1024;
@@ -1199,7 +1201,7 @@
mapping_set_gfp_mask(fs_info->btree_inode->i_mapping, GFP_NOFS);
mutex_init(&fs_info->trans_mutex);
- mutex_init(&fs_info->fs_mutex);
+ mutex_init(&fs_info->drop_mutex);
mutex_init(&fs_info->alloc_mutex);
mutex_init(&fs_info->chunk_mutex);
@@ -1278,8 +1280,6 @@
goto fail_sb_buffer;
}
- mutex_lock(&fs_info->fs_mutex);
-
mutex_lock(&fs_info->chunk_mutex);
ret = btrfs_read_sys_array(tree_root);
mutex_unlock(&fs_info->chunk_mutex);
@@ -1342,7 +1342,6 @@
fs_info->metadata_alloc_profile = (u64)-1;
fs_info->system_alloc_profile = fs_info->metadata_alloc_profile;
- mutex_unlock(&fs_info->fs_mutex);
return tree_root;
fail_extent_root:
@@ -1350,7 +1349,6 @@
fail_tree_root:
free_extent_buffer(tree_root->node);
fail_sys_array:
- mutex_unlock(&fs_info->fs_mutex);
fail_sb_buffer:
extent_io_tree_empty_lru(&BTRFS_I(fs_info->btree_inode)->io_tree);
btrfs_stop_workers(&fs_info->workers);
@@ -1562,8 +1560,9 @@
struct btrfs_fs_info *fs_info = root->fs_info;
fs_info->closing = 1;
+ smp_mb();
+
btrfs_transaction_flush_work(root);
- mutex_lock(&fs_info->fs_mutex);
btrfs_defrag_dirty_roots(root->fs_info);
trans = btrfs_start_transaction(root, 1);
ret = btrfs_commit_transaction(trans, root);
@@ -1574,7 +1573,6 @@
BUG_ON(ret);
write_ctree_super(NULL, root);
- mutex_unlock(&fs_info->fs_mutex);
btrfs_transaction_flush_work(root);
@@ -1679,7 +1677,8 @@
struct backing_dev_info *bdi;
bdi = &root->fs_info->bdi;
- if (root->fs_info->throttles && bdi_write_congested(bdi)) {
+ if (atomic_read(&root->fs_info->throttles) &&
+ bdi_write_congested(bdi)) {
#if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,18)
congestion_wait(WRITE, HZ/20);
#else