On 2020/5/14 下午4:08, Qu Wenruo wrote: > > > On 2020/5/13 下午8:21, Zygo Blaxell wrote: >> On Wed, May 13, 2020 at 07:23:40PM +0800, Qu Wenruo wrote: >>> >>> > [...] >> >> Kernel log: >> >> [96199.614869][ T9676] BTRFS info (device dm-0): balance: start -d >> [96199.616086][ T9676] BTRFS info (device dm-0): relocating block group 4396679168000 flags data >> [96199.782217][ T9676] BTRFS info (device dm-0): relocating block group 4395605426176 flags data >> [96199.971118][ T9676] BTRFS info (device dm-0): relocating block group 4394531684352 flags data >> [96220.858317][ T9676] BTRFS info (device dm-0): found 13 extents, loops 1, stage: move data extents >> [...] >> [121403.509718][ T9676] BTRFS info (device dm-0): found 13 extents, loops 131823, stage: update data pointers >> (qemu) stop >> >> btrfs-image URL: >> >> http://www.furryterror.org/~zblaxell/tmp/.fsinqz/image.bin >> > The image shows several very strange result. > > For one, although we're relocating block group 4394531684352, the > previous two block groups doesn't really get relocated. > > There are still extents there, all belongs to data reloc tree. > > Furthermore, the data reloc tree inode 620 should be evicted when > previous block group relocation finishes. > > So I'm considering something went wrong in data reloc tree, would you > please try the following diff? > (Either on vanilla kernel or with my previous useless patch) Oh, my previous testing patch is doing wrong inode put for data reloc tree, thus it's possible to lead to such situation. Thankfully the v2 for upstream gets the problem fixed. Thus it goes back to the original stage, still no faster way to reproduce the problem... Thanks, Qu > > Thanks, > Qu > > diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c > index 9afc1a6928cf..ef9e18bab6f6 100644 > --- a/fs/btrfs/relocation.c > +++ b/fs/btrfs/relocation.c > @@ -3498,6 +3498,7 @@ struct inode *create_reloc_inode(struct > btrfs_fs_info *fs_info, > BTRFS_I(inode)->index_cnt = group->start; > > err = btrfs_orphan_add(trans, BTRFS_I(inode)); > + WARN_ON(atomic_read(inode->i_count) != 1); > out: > btrfs_put_root(root); > btrfs_end_transaction(trans); > @@ -3681,6 +3682,7 @@ int btrfs_relocate_block_group(struct > btrfs_fs_info *fs_info, u64 group_start) > out: > if (err && rw) > btrfs_dec_block_group_ro(rc->block_group); > + WARN_ON(atomic_read(inode->i_count) != 1); > iput(rc->data_inode); > btrfs_put_block_group(rc->block_group); > free_reloc_control(rc); >
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