btrfs: use correct offset for reloc_inode in prealloc_file_extent_cluster()

In prealloc_file_extent_cluster(), btrfs_check_data_free_space() uses
wrong file offset for reloc_inode, it uses cluster->start and cluster->end,
which indeed are extent's bytenr. The correct value should be
cluster->[start|end] minus block group's start bytenr.

start bytenr   cluster->start
|              |     extent      |   extent   | ...| extent |
|----------------------------------------------------------------|
|                block group reloc_inode                         |

Signed-off-by: Wang Xiaoguang <wangxg.fnst@cn.fujitsu.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>

diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index 27480ef..71b4b70 100644 (file)
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -3038,12 +3038,14 @@ int prealloc_file_extent_cluster(struct inode *inode,
        u64 num_bytes;
        int nr = 0;
        int ret = 0;
+       u64 prealloc_start = cluster->start - offset;
+       u64 prealloc_end = cluster->end - offset;
 
        BUG_ON(cluster->start != cluster->boundary[0]);
        inode_lock(inode);
 
-       ret = btrfs_check_data_free_space(inode, cluster->start,
-                                         cluster->end + 1 - cluster->start);
+       ret = btrfs_check_data_free_space(inode, prealloc_start,
+                                         prealloc_end + 1 - prealloc_start);
        if (ret)
                goto out;
 
@@ -3064,8 +3066,8 @@ int prealloc_file_extent_cluster(struct inode *inode,
                        break;
                nr++;
        }
-       btrfs_free_reserved_data_space(inode, cluster->start,
-                                      cluster->end + 1 - cluster->start);
+       btrfs_free_reserved_data_space(inode, prealloc_start,
+                                      prealloc_end + 1 - prealloc_start);
 out:
        inode_unlock(inode);
        return ret;