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Bug #18269

closed

rbd info truncates block_name_prefix to 23 chars

Added by Achim Ledermüller over 7 years ago. Updated over 7 years ago.

Status:
Duplicate
Priority:
High
Assignee:
-
Target version:
-
% Done:

0%

Source:
Community (user)
Tags:
Backport:
Regression:
No
Severity:
3 - minor
Reviewed:
Affected Versions:
Ceph - v10.2.4, Ceph - v10.2.5
ceph-qa-suite:
Pull request ID:
Crash signature (v1):
Crash signature (v2):

Description

Hi,

Since 10.2.4/5 rbd info truncates the block_name_prefix to 23 chars. Version 10.2.3 shows the prefix with 24 chars. Also rbd status is affected and can't list the watchers. Creating RBDs with version 10.2.4/5 leads to RBDs with a block_name_prefix of 23 chars, as well.

The same image with different rbd client versions:

root@v10.2.5:~# rbd info 0ea7f52850cc851139d1118556a35f691230a0120e08795fd5ea398e779e865d
rbd image '0ea7f52850cc851139d1118556a35f691230a0120e08795fd5ea398e779e865d':
    size 20480 MB in 5120 objects
    order 22 (4096 kB objects)
    block_name_prefix: rbd_data.915a555238e1f2
    format: 2
    features: layering
    flags: 
root@v10.2.5:~# echo -n "rbd_data.915a555238e1f2" | wc -c
23

root@v10.2.3:~# rbd -p mesos info 0ea7f52850cc851139d1118556a35f691230a0120e08795fd5ea398e779e865d
rbd image '0ea7f52850cc851139d1118556a35f691230a0120e08795fd5ea398e779e865d':
    size 20480 MB in 5120 objects
    order 22 (4096 kB objects)
    block_name_prefix: rbd_data.915a555238e1f29
    format: 2
    features: layering
    flags: 
root@v10.2.3:~# echo -n "rbd_data.915a555238e1f29" | wc -c
24

I don't think this is the same problem as in #16887, where the block_name_prefix is 25 chars, which is larger than RBD_MAX_BLOCK_NAME_SIZE.

Regards,
Achim

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 #1

Updated by Mykola Golub over 7 years ago

This has been changed when fixing this issue: http://tracker.ceph.com/issues/17310

I think we can return the old behavior for `rbd info` if backport new API get_block_name_prefix() function from this PR: https://github.com/ceph/ceph/pull/11353

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 #2

Updated by Jason Dillaman over 7 years ago

The issue is that the legacy API only supports 23 characters (plus an additional null byte) to represent the block name prefix. Since there was a bug that did not properly restrict the block name prefix, lots of images in deployed clusters have block names that cannot be represented in via the existing API method.

I opened ticket #18270 to backport the new API methods (and deprecate the old one) which will fix this issue for you.

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 #3

Updated by Jason Dillaman over 7 years ago

  • Status changed from New to Duplicate
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