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Wang Shilong authored
We should gurantee that parent and clone roots can not be destroyed during send, for this we have two ideas. 1.by holding @subvol_sem, this might be a nightmare, because it will block all subvolumes deletion for a long time. 2.Miao pointed out we can reuse @send_in_progress, that mean we will skip snapshot deletion if root sending is in progress. Here we adopt the second approach since it won't block other subvolumes deletion for a long time. Besides in btrfs_clean_one_deleted_snapshot(), we only check first root , if this root is involved in send, we return directly rather than continue to check.There are several reasons about it: 1.this case happen seldomly. 2.after sending,cleaner thread can continue to drop that root. 3.make code simple Cc: David Sterba <dsterba@suse.cz> Signed-off-by:
Wang Shilong <wangsl.fnst@cn.fujitsu.com> Reviewed-by:
Miao Xie <miaox@cn.fujitsu.com> Signed-off-by:
Josef Bacik <jbacik@fb.com> Signed-off-by:
Chris Mason <clm@fb.com>
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