• Z
    btrfs: Fix NO_SPACE bug caused by delayed-iput · d7c15171
    Zhao Lei 提交于
    Steps to reproduce:
      while true; do
        dd if=/dev/zero of=/btrfs_dir/file count=[fs_size * 75%]
        rm /btrfs_dir/file
        sync
      done
    
      And we'll see dd failed because btrfs return NO_SPACE.
    
    Reason:
      Normally, btrfs_commit_transaction() call btrfs_run_delayed_iputs()
      in end to free fs space for next write, but sometimes it hadn't
      done work on time, because btrfs-cleaner thread get delayed-iputs
      from list before, but do iput() after next write.
    
      This is log:
      [ 2569.050776] comm=btrfs-cleaner func=btrfs_evict_inode() begin
    
      [ 2569.084280] comm=sync func=btrfs_commit_transaction() call btrfs_run_delayed_iputs()
      [ 2569.085418] comm=sync func=btrfs_commit_transaction() done btrfs_run_delayed_iputs()
      [ 2569.087554] comm=sync func=btrfs_commit_transaction() end
    
      [ 2569.191081] comm=dd begin
      [ 2569.790112] comm=dd func=__btrfs_buffered_write() ret=-28
    
      [ 2569.847479] comm=btrfs-cleaner func=add_pinned_bytes() 0 + 32677888 = 32677888
      [ 2569.849530] comm=btrfs-cleaner func=add_pinned_bytes() 32677888 + 23834624 = 56512512
      ...
      [ 2569.903893] comm=btrfs-cleaner func=add_pinned_bytes() 943976448 + 21762048 = 965738496
      [ 2569.908270] comm=btrfs-cleaner func=btrfs_evict_inode() end
    
    Fix:
      Make btrfs_commit_transaction() wait current running btrfs-cleaner's
      delayed-iputs() done in end.
    
    Test:
      Use script similar to above(more complex),
      before patch:
        7 failed in 100 * 20 loop.
      after patch:
        0 failed in 100 * 20 loop.
    Signed-off-by: NZhao Lei <zhaolei@cn.fujitsu.com>
    Signed-off-by: NChris Mason <clm@fb.com>
    d7c15171
disk-io.c 117.7 KB