On Mon, Sep 17, 2012 at 4:58 AM, Liu Bo <bo.li....@oracle.com> wrote: > This comes from one of btrfs's project ideas, > As we defragment files, we break any sharing from other snapshots. > The balancing code will preserve the sharing, and defrag needs to grow this > as well. > > Now we're able to fill the blank with this patch, in which we make full use of > backref walking stuff. > > Here is the basic idea, > o set the writeback ranges started by defragment with flag EXTENT_DEFRAG > o at endio, after we finish updating fs tree, we use backref walking to find > all parents of the ranges and re-link them with the new COWed file layout > by > adding corresponding backrefs. > > Originally patch by Li Zefan <l...@cn.fujitsu.com> > Signed-off-by: Liu Bo <bo.li....@oracle.com>
I'm hitting the WARN_ON in record_extent_backrefs() indicating a problem with the return value from iterate_inodes_from_logical(). [ 6865.184782] ------------[ cut here ]------------ [ 6865.184819] WARNING: at fs/btrfs/inode.c:2062 record_extent_backrefs+0xe5/0xe7 [btrfs]() [ 6865.184823] Hardware name: OptiPlex 745 [ 6865.184825] Modules linked in: lpc_ich mfd_core xts gf128mul cryptd aes_x86_64 sha256_generic btrfs libcrc32c [ 6865.184841] Pid: 4239, comm: btrfs-endio-wri Not tainted 3.5.4-git-local+ #1 [ 6865.184844] Call Trace: [ 6865.184856] [<ffffffff81031d6a>] warn_slowpath_common+0x74/0xa2 [ 6865.184862] [<ffffffff81031db2>] warn_slowpath_null+0x1a/0x1c [ 6865.184884] [<ffffffffa003356b>] record_extent_backrefs+0xe5/0xe7 [btrfs] [ 6865.184908] [<ffffffffa003cf3a>] btrfs_finish_ordered_io+0x131/0xa4b [btrfs] [ 6865.184930] [<ffffffffa003d869>] finish_ordered_fn+0x15/0x17 [btrfs] [ 6865.184951] [<ffffffffa005882f>] worker_loop+0x145/0x516 [btrfs] [ 6865.184959] [<ffffffff81059727>] ? __wake_up_common+0x54/0x84 [ 6865.184983] [<ffffffffa00586ea>] ? btrfs_queue_worker+0x2d3/0x2d3 [btrfs] [ 6865.184989] [<ffffffff810516bb>] kthread+0x93/0x98 [ 6865.184996] [<ffffffff817d7934>] kernel_thread_helper+0x4/0x10 [ 6865.185001] [<ffffffff81051628>] ? kthread_freezable_should_stop+0x6a/0x6a [ 6865.185021] [<ffffffff817d7930>] ? gs_change+0xb/0xb [ 6865.185025] ---[ end trace 26cc0e186efc79d8 ]--- I'm testing a 3.5.4 kernel merged with 3.6_rc patchset as well as the send_recv patches and most of the btrfs-next patches. I'm running into this issue when mounting with autodefrag, and running some snapshot tests. This may be related to a problem elsewhere, because I've been encountering other backref issues even before testing this patch. -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
