Commits
Wang Shilong committed c974c4642fe
Btrfs: fix an oops when doing balance relocation I hit an oops when inserting reloc root into @reloc_root_tree(it can be easily triggered when forcing cow for relocation root) [ 866.494539] [<ffffffffa0499579>] btrfs_init_reloc_root+0x79/0xb0 [btrfs] [ 866.495321] [<ffffffffa044c240>] record_root_in_trans+0xb0/0x110 [btrfs] [ 866.496109] [<ffffffffa044d758>] btrfs_record_root_in_trans+0x48/0x80 [btrfs] [ 866.496908] [<ffffffffa0494da8>] select_reloc_root+0xa8/0x210 [btrfs] [ 866.497703] [<ffffffffa0495c8a>] do_relocation+0x16a/0x540 [btrfs] This is because reloc root inserted into @reloc_root_tree is not within one transaction,reloc root may be cowed and root block bytenr will be reused then oops happens.We should update reloc root in @reloc_root_tree when cow reloc root node, fix it. Signed-off-by: Wang Shilong <wangsl.fnst@cn.fujitsu.com> Reviewed-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Chris Mason <clm@fb.com>