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Commit 61cfea9b authored by WuBo's avatar WuBo Committed by Chris Mason
Browse files

Btrfs: Protect the readonly flag of block group 



The access for ro in btrfs_block_group_cache should be protected
because of the racy lock in relocation.

Signed-off-by: default avatarWu Bo <wu.bo@cn.fujitsu.com>
Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
parent 1bf85046

fs/btrfs/extent-tree.c

+7 −3
Original line number Diff line number Diff line
@@ -6549,8 +6549,6 @@ static int set_block_group_ro(struct btrfs_block_group_cache *cache, int force) 
	u64 min_allocable_bytes;

	int ret = -ENOSPC;



	if (cache->ro)

		return 0;



	/*

	 * We need some metadata space and system metadata space for
@@ -6566,6 +6564,12 @@ static int set_block_group_ro(struct btrfs_block_group_cache *cache, int force) 


	spin_lock(&sinfo->lock);

	spin_lock(&cache->lock);



	if (cache->ro) {

		ret = 0;

		goto out;

	}



	num_bytes = cache->key.offset - cache->reserved - cache->pinned -

		    cache->bytes_super - btrfs_block_group_used(&cache->item);
@@ -6579,7 +6583,7 @@ static int set_block_group_ro(struct btrfs_block_group_cache *cache, int force) 
		cache->ro = 1;

		ret = 0;

	}



out:

	spin_unlock(&cache->lock);

	spin_unlock(&sinfo->lock);

	return ret;