From: "Yan, Zheng" <zheng.yan@oracle.com>
To: linux-btrfs@vger.kernel.org
Cc: Chris Mason <chris.mason@oracle.com>
Subject: [RFC] log mode COW
Date: Tue, 11 May 2010 16:23:33 +0800 [thread overview]
Message-ID: <4BE91405.6080006@oracle.com> (raw)
The aim of log mode COW is solve extent tree performance issue when
free metadata space are scarce and fragmented. The basic idea is:
when cowing a non-shared block, we insert a log entry that maps
the new block to the old block into a special log tree, and do not
update the extent tree. After transaction is fully committed, copy
the new block back to the old location.
Log mode COW can be enabled/disabled by log_mode=%d mount option.
'0' means disable log mode COW; '1' means enable log for tree blocks
that are not reference counted; '2' means enable log for all tree
blocks are not shared.
NOTE: The patch series base on current btrfs-unstable. They are for
test and review only. Enable log mode COW changes disk format.
Regards
Yan, Zheng
reply other threads:[~2010-05-11 8:23 UTC|newest]
Thread overview: [no followups] expand[flat|nested] mbox.gz Atom feed
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=4BE91405.6080006@oracle.com \
--to=zheng.yan@oracle.com \
--cc=chris.mason@oracle.com \
--cc=linux-btrfs@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).