btrfs: rename delete_unused_bgs_mutex to reclaim_bgs_lock

As a preparation for extending the block group deletion use case, rename
the unused_bgs_mutex to reclaim_bgs_lock.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/block-group.c

@@ -1289,7 +1289,7 @@ void btrfs_delete_unused_bgs(struct btrfs_fs_info *fs_info)
 	 * Long running balances can keep us blocked here for eternity, so
 	 * simply skip deletion if we're unable to get the mutex.
 	 */
-	if (!mutex_trylock(&fs_info->delete_unused_bgs_mutex))
+	if (!mutex_trylock(&fs_info->reclaim_bgs_lock))
 		return;
 
 	spin_lock(&fs_info->unused_bgs_lock);
@@ -1462,12 +1462,12 @@ void btrfs_delete_unused_bgs(struct btrfs_fs_info *fs_info)
 		spin_lock(&fs_info->unused_bgs_lock);
 	}
 	spin_unlock(&fs_info->unused_bgs_lock);
-	mutex_unlock(&fs_info->delete_unused_bgs_mutex);
+	mutex_unlock(&fs_info->reclaim_bgs_lock);
 	return;
 
 flip_async:
 	btrfs_end_transaction(trans);
-	mutex_unlock(&fs_info->delete_unused_bgs_mutex);
+	mutex_unlock(&fs_info->reclaim_bgs_lock);
 	btrfs_put_block_group(block_group);
 	btrfs_discard_punt_unused_bgs_list(fs_info);
 }

fs/btrfs/ctree.h

@@ -963,7 +963,8 @@ struct btrfs_fs_info {
 	spinlock_t unused_bgs_lock;
 	struct list_head unused_bgs;
 	struct mutex unused_bg_unpin_mutex;
-	struct mutex delete_unused_bgs_mutex;
+	/* Protect block groups that are going to be deleted */
+	struct mutex reclaim_bgs_lock;
 
 	/* Cached block sizes */
 	u32 nodesize;

fs/btrfs/disk-io.c

@@ -1890,10 +1890,10 @@ static int cleaner_kthread(void *arg)
 		btrfs_run_defrag_inodes(fs_info);
 
 		/*
-		 * Acquires fs_info->delete_unused_bgs_mutex to avoid racing
+		 * Acquires fs_info->reclaim_bgs_lock to avoid racing
 		 * with relocation (btrfs_relocate_chunk) and relocation
 		 * acquires fs_info->cleaner_mutex (btrfs_relocate_block_group)
-		 * after acquiring fs_info->delete_unused_bgs_mutex. So we
+		 * after acquiring fs_info->reclaim_bgs_lock. So we
 		 * can't hold, nor need to, fs_info->cleaner_mutex when deleting
 		 * unused block groups.
 		 */
@@ -2876,7 +2876,7 @@ void btrfs_init_fs_info(struct btrfs_fs_info *fs_info)
 	spin_lock_init(&fs_info->treelog_bg_lock);
 	rwlock_init(&fs_info->tree_mod_log_lock);
 	mutex_init(&fs_info->unused_bg_unpin_mutex);
-	mutex_init(&fs_info->delete_unused_bgs_mutex);
+	mutex_init(&fs_info->reclaim_bgs_lock);
 	mutex_init(&fs_info->reloc_mutex);
 	mutex_init(&fs_info->delalloc_root_mutex);
 	mutex_init(&fs_info->zoned_meta_io_lock);

fs/btrfs/volumes.c

@@ -3118,7 +3118,7 @@ static int btrfs_relocate_chunk(struct btrfs_fs_info *fs_info, u64 chunk_offset)
 	 * we release the path used to search the chunk/dev tree and before
 	 * the current task acquires this mutex and calls us.
 	 */
-	lockdep_assert_held(&fs_info->delete_unused_bgs_mutex);
+	lockdep_assert_held(&fs_info->reclaim_bgs_lock);
 
 	/* step one, relocate all the extents inside this chunk */
 	btrfs_scrub_pause(fs_info);
@@ -3188,10 +3188,10 @@ static int btrfs_relocate_sys_chunks(struct btrfs_fs_info *fs_info)
 	key.type = BTRFS_CHUNK_ITEM_KEY;
 
 	while (1) {
-		mutex_lock(&fs_info->delete_unused_bgs_mutex);
+		mutex_lock(&fs_info->reclaim_bgs_lock);
 		ret = btrfs_search_slot(NULL, chunk_root, &key, path, 0, 0);
 		if (ret < 0) {
-			mutex_unlock(&fs_info->delete_unused_bgs_mutex);
+			mutex_unlock(&fs_info->reclaim_bgs_lock);
 			goto error;
 		}
 		BUG_ON(ret == 0); /* Corruption */
@@ -3199,7 +3199,7 @@ static int btrfs_relocate_sys_chunks(struct btrfs_fs_info *fs_info)
 		ret = btrfs_previous_item(chunk_root, path, key.objectid,
 					  key.type);
 		if (ret)
-			mutex_unlock(&fs_info->delete_unused_bgs_mutex);
+			mutex_unlock(&fs_info->reclaim_bgs_lock);
 		if (ret < 0)
 			goto error;
 		if (ret > 0)
@@ -3220,7 +3220,7 @@ static int btrfs_relocate_sys_chunks(struct btrfs_fs_info *fs_info)
 			else
 				BUG_ON(ret);
 		}
-		mutex_unlock(&fs_info->delete_unused_bgs_mutex);
+		mutex_unlock(&fs_info->reclaim_bgs_lock);
 
 		if (found_key.offset == 0)
 			break;
@@ -3760,10 +3760,10 @@ static int __btrfs_balance(struct btrfs_fs_info *fs_info)
 			goto error;
 		}
 
-		mutex_lock(&fs_info->delete_unused_bgs_mutex);
+		mutex_lock(&fs_info->reclaim_bgs_lock);
 		ret = btrfs_search_slot(NULL, chunk_root, &key, path, 0, 0);
 		if (ret < 0) {
-			mutex_unlock(&fs_info->delete_unused_bgs_mutex);
+			mutex_unlock(&fs_info->reclaim_bgs_lock);
 			goto error;
 		}
 
@@ -3777,7 +3777,7 @@ static int __btrfs_balance(struct btrfs_fs_info *fs_info)
 		ret = btrfs_previous_item(chunk_root, path, 0,
 					  BTRFS_CHUNK_ITEM_KEY);
 		if (ret) {
-			mutex_unlock(&fs_info->delete_unused_bgs_mutex);
+			mutex_unlock(&fs_info->reclaim_bgs_lock);
 			ret = 0;
 			break;
 		}
@@ -3787,7 +3787,7 @@ static int __btrfs_balance(struct btrfs_fs_info *fs_info)
 		btrfs_item_key_to_cpu(leaf, &found_key, slot);
 
 		if (found_key.objectid != key.objectid) {
-			mutex_unlock(&fs_info->delete_unused_bgs_mutex);
+			mutex_unlock(&fs_info->reclaim_bgs_lock);
 			break;
 		}
 
@@ -3804,12 +3804,12 @@ static int __btrfs_balance(struct btrfs_fs_info *fs_info)
 
 		btrfs_release_path(path);
 		if (!ret) {
-			mutex_unlock(&fs_info->delete_unused_bgs_mutex);
+			mutex_unlock(&fs_info->reclaim_bgs_lock);
 			goto loop;
 		}
 
 		if (counting) {
-			mutex_unlock(&fs_info->delete_unused_bgs_mutex);
+			mutex_unlock(&fs_info->reclaim_bgs_lock);
 			spin_lock(&fs_info->balance_lock);
 			bctl->stat.expected++;
 			spin_unlock(&fs_info->balance_lock);
@@ -3834,7 +3834,7 @@ static int __btrfs_balance(struct btrfs_fs_info *fs_info)
 					count_meta < bctl->meta.limit_min)
 				|| ((chunk_type & BTRFS_BLOCK_GROUP_SYSTEM) &&
 					count_sys < bctl->sys.limit_min)) {
-			mutex_unlock(&fs_info->delete_unused_bgs_mutex);
+			mutex_unlock(&fs_info->reclaim_bgs_lock);
 			goto loop;
 		}
 
@@ -3848,7 +3848,7 @@ static int __btrfs_balance(struct btrfs_fs_info *fs_info)
 			ret = btrfs_may_alloc_data_chunk(fs_info,
 							 found_key.offset);
 			if (ret < 0) {
-				mutex_unlock(&fs_info->delete_unused_bgs_mutex);
+				mutex_unlock(&fs_info->reclaim_bgs_lock);
 				goto error;
 			} else if (ret == 1) {
 				chunk_reserved = 1;
@@ -3856,7 +3856,7 @@ static int __btrfs_balance(struct btrfs_fs_info *fs_info)
 		}
 
 		ret = btrfs_relocate_chunk(fs_info, found_key.offset);
-		mutex_unlock(&fs_info->delete_unused_bgs_mutex);
+		mutex_unlock(&fs_info->reclaim_bgs_lock);
 		if (ret == -ENOSPC) {
 			enospc_errors++;
 		} else if (ret == -ETXTBSY) {
@@ -4741,16 +4741,16 @@ int btrfs_shrink_device(struct btrfs_device *device, u64 new_size)
 	key.type = BTRFS_DEV_EXTENT_KEY;
 
 	do {
-		mutex_lock(&fs_info->delete_unused_bgs_mutex);
+		mutex_lock(&fs_info->reclaim_bgs_lock);
 		ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 		if (ret < 0) {
-			mutex_unlock(&fs_info->delete_unused_bgs_mutex);
+			mutex_unlock(&fs_info->reclaim_bgs_lock);
 			goto done;
 		}
 
 		ret = btrfs_previous_item(root, path, 0, key.type);
 		if (ret) {
-			mutex_unlock(&fs_info->delete_unused_bgs_mutex);
+			mutex_unlock(&fs_info->reclaim_bgs_lock);
 			if (ret < 0)
 				goto done;
 			ret = 0;
@@ -4763,7 +4763,7 @@ int btrfs_shrink_device(struct btrfs_device *device, u64 new_size)
 		btrfs_item_key_to_cpu(l, &key, path->slots[0]);
 
 		if (key.objectid != device->devid) {
-			mutex_unlock(&fs_info->delete_unused_bgs_mutex);
+			mutex_unlock(&fs_info->reclaim_bgs_lock);
 			btrfs_release_path(path);
 			break;
 		}
@@ -4772,7 +4772,7 @@ int btrfs_shrink_device(struct btrfs_device *device, u64 new_size)
 		length = btrfs_dev_extent_length(l, dev_extent);
 
 		if (key.offset + length <= new_size) {
-			mutex_unlock(&fs_info->delete_unused_bgs_mutex);
+			mutex_unlock(&fs_info->reclaim_bgs_lock);
 			btrfs_release_path(path);
 			break;
 		}
@@ -4788,12 +4788,12 @@ int btrfs_shrink_device(struct btrfs_device *device, u64 new_size)
 		 */
 		ret = btrfs_may_alloc_data_chunk(fs_info, chunk_offset);
 		if (ret < 0) {
-			mutex_unlock(&fs_info->delete_unused_bgs_mutex);
+			mutex_unlock(&fs_info->reclaim_bgs_lock);
 			goto done;
 		}
 
 		ret = btrfs_relocate_chunk(fs_info, chunk_offset);
-		mutex_unlock(&fs_info->delete_unused_bgs_mutex);
+		mutex_unlock(&fs_info->reclaim_bgs_lock);
 		if (ret == -ENOSPC) {
 			failed++;
 		} else if (ret) {
@@ -8068,7 +8068,7 @@ static int relocating_repair_kthread(void *data)
 		return -EBUSY;
 	}
 
-	mutex_lock(&fs_info->delete_unused_bgs_mutex);
+	mutex_lock(&fs_info->reclaim_bgs_lock);
 
 	/* Ensure block group still exists */
 	cache = btrfs_lookup_block_group(fs_info, target);
@@ -8090,7 +8090,7 @@ static int relocating_repair_kthread(void *data)
 out:
 	if (cache)
 		btrfs_put_block_group(cache);
-	mutex_unlock(&fs_info->delete_unused_bgs_mutex);
+	mutex_unlock(&fs_info->reclaim_bgs_lock);
 	btrfs_exclop_finish(fs_info);
 
 	return ret;