[LU-13426] "lfs migrate" on DoM component clobbers LOV EA FID

Duplicate — Fri, 9 Jul 2021 18:08:17 +0000

Running the following test breaks the FID stored in the LOV EA. I was hoping that this FID would remain constant over the life of the file in order to implement LU-7607 "Preserve inode number after MDT migration", but it seems that migrating a file with a DOM component somehow breaks the layout in the LOV EA:

tests# lfs setstripe -E 1M -L mdt -E 1G -c 3 -E eof /mnt/testfs/tt
tests# dd if=/dev/zero of=/mnt/testfs/tt bs=1M count=2
tests# lfs path2fid /mnt/testfs/tt
[0x200001b72:0x10c07:0x0]
tests# lfs getstripe -v /mnt/testfs/tt
components:
  - lcme_id:             1
    lcme_extent.e_start: 0
    lcme_extent.e_end:   1048576
    sub_layout:
      lmm_seq:           0x200001b72
      lmm_object_id:     0x10c07
      lmm_fid:           [0x200001b72:0x10c07:0x0]
      lmm_stripe_count:  0
      lmm_pattern:       mdt
  - lcme_id:             2
    lcme_extent.e_start: 1048576
    lcme_extent.e_end:   1073741824
    sub_layout:
      lmm_seq:           0x200001b72
      lmm_object_id:     0x10c07
      lmm_fid:           [0x200001b72:0x10c07:0x0]
  - lcme_id:             3
    lcme_extent.e_start: 1073741824
    lcme_extent.e_end:   EOF
    sub_layout:
      lmm_seq:           0x200001b72
      lmm_object_id:     0x10c07
      lmm_fid:           [0x200001b72:0x10c07:0x0]

tests# lfs migrate -c 3 /mnt/testfs/tt
tests# lfs getstripe -v /mnt/testfs/tt
lmm_seq:           0
lmm_object_id:     0x3000000000005
lmm_fid:           [0x3000000000005:0x0:0x30000]

As you can see, the FID is originally [0x200001b72:0x10c07:0x0] and that is also stored in the LOV EA (irrelevant lines cut out) for each component as lmm_fid:, which is good. If there is no DOM component, then "lfs migrate -m" will not change the FID stored in the layout. However, as can be seen with a DOM component, the lmm_fid: is messed up. It looks like it wasn't initialized in the target layout, and/or not copied over during layout swap.

Whamcloud Community JIRA

[LU-13426] "lfs migrate" on DoM component clobbers LOV EA FID