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authorWuBo <wu.bo@cn.fujitsu.com>2011-07-26 03:30:11 +0000
committerChris Mason <chris.mason@oracle.com>2011-08-01 14:30:43 -0400
commit61cfea9bb84d41b09e59822c33b3eb27acc48358 (patch)
tree6c20e098a3be7aad77419dc273bfd670dc470f3a /fs
parent1bf85046e493c88be1c1bad9084428373089f618 (diff)
downloadlinux-61cfea9bb84d41b09e59822c33b3eb27acc48358.tar.gz
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: Wu Bo <wu.bo@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Diffstat (limited to 'fs')
-rw-r--r--fs/btrfs/extent-tree.c10
1 files changed, 7 insertions, 3 deletions
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index db2057f262ad..a4db88da125e 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -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;