Feature #54280: support truncation sequences in sparse reads - RADOS - Ceph

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Feature #54280

closed

support truncation sequences in sparse reads

Added by Jeff Layton about 2 years ago. Updated about 1 year ago.

Status:

Resolved

Priority:

Normal

Assignee:

Category:

Target version:

% Done:

Source:

Tags:

backport_processed

Backport:

quincy

Reviewed:

Affected Versions:

Component(RADOS):

Pull request ID:

45103

Description

I've been working on sparse read support in the kclient, and got something working today, only to notice that after truncating a file, I would often get back -EINVAL when trying to read it. The problem seems to be this in PrimaryLogPG::do_sparse_read() :

  if (op.extent.truncate_seq) {
    dout(0) << "sparse_read does not support truncation sequence " << dendl;
    return -EINVAL;
  }

Would it be possible to support sparse reads against objects that have a non-zero truncate_seq?

Related issues 1 (0 open — 1 closed)

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Updated by Jeff Layton about 2 years ago

Neha mentioned taking a look at the history, so I did a bit of git archeology today. The limitation dates back to the original merge of sparse_read support:

commit 6f38165dc5df8a2f29e021ad1b16facf55120a9b
Author: Yehuda Sadeh <yehuda@inktank.com>
Date:   Thu Aug 5 15:58:55 2010 -0700

    osd: implement sparse_read

Yehuda, do you happen to remember why this is a problem for sparse reads, and (possibly) how to fix it?

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