From: Olaf Weber <olaf@sgi.com>
To: Eric Sandeen <sandeen@sandeen.net>
Cc: xfs mailing list <xfs@oss.sgi.com>
Subject: Re: [PATCH] reduce bmv_count in xfs_vn_fiemap
Date: Thu, 16 Jul 2009 12:56:21 +0200 [thread overview]
Message-ID: <bzybpnkhp62.fsf@fransum.emea.sgi.com> (raw)
In-Reply-To: <4A5E2F01.7030107@sandeen.net> (Eric Sandeen's message of "Wed, 15 Jul 2009 14:33:21 -0500")
Eric Sandeen writes:
> commit 6321e3ed2acf3ee9643cdd403e1c88605d7944ba caused
> the full bmv_count's worth of getbmapx structures to get
> allocated; telling it to do MAXEXTNUM was a bit insane,
> resulting in ENOMEM.
> Chop it down to something reasonable, the caller can
> loop over this if the file has > 64 extents.
It does seem to me that this will result in an unusal case for the
caller, in that it will get fewer extents than fit in the provided
buffer, yet should loop. Do current callers know that they can hit
this case, detect it, and loop accordingly? Or is this just pushing
the problem/regression to userspace?
> (this is a regression, FWIW)
> Signed-off-by: Eric Sandeen <sandeen@sandeen.net>
> ---
> iff --git a/fs/xfs/linux-2.6/xfs_iops.c b/fs/xfs/linux-2.6/xfs_iops.c
> index 58973bb..370e9a7 100644
> --- a/fs/xfs/linux-2.6/xfs_iops.c
> +++ b/fs/xfs/linux-2.6/xfs_iops.c
> @@ -680,8 +680,12 @@ xfs_vn_fiemap(
> else
> bm.bmv_length = BTOBB(length);
> - /* our formatter will tell xfs_getbmap when to stop. */
> - bm.bmv_count = MAXEXTNUM;
> + /*
> + * xfs_getbmap allocates based on that; pick a count that's
> + * not too outragous.
> + * Our formatter will tell xfs_getbmap when to stop.
> + */
> + bm.bmv_count = 64;
> bm.bmv_iflags = BMV_IF_PREALLOC;
> if (fieinfo->fi_flags & FIEMAP_FLAG_XATTR)
> bm.bmv_iflags |= BMV_IF_ATTRFORK;
--
Olaf Weber SGI Phone: +31(0)30-6696752
Veldzigt 2b Fax: +31(0)30-6696799
Technical Lead 3454 PW de Meern Vnet: 955-7151
Storage Software The Netherlands Email: olaf@sgi.com
_______________________________________________
xfs mailing list
xfs@oss.sgi.com
http://oss.sgi.com/mailman/listinfo/xfs
next prev parent reply other threads:[~2009-07-16 10:55 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-07-15 19:33 [PATCH] reduce bmv_count in xfs_vn_fiemap Eric Sandeen
2009-07-16 10:56 ` Olaf Weber [this message]
2009-07-16 14:19 ` Eric Sandeen
2009-07-16 14:48 ` [PATCH V2] " Eric Sandeen
2009-07-16 15:18 ` Olaf Weber
2009-07-16 19:11 ` [PATCH V3] " Eric Sandeen
2009-07-17 11:46 ` Olaf Weber
2009-07-18 14:25 ` Christoph Hellwig
2009-07-27 2:52 ` [PATCH V4] " Eric Sandeen
2009-07-27 7:55 ` Olaf Weber
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=bzybpnkhp62.fsf@fransum.emea.sgi.com \
--to=olaf@sgi.com \
--cc=sandeen@sandeen.net \
--cc=xfs@oss.sgi.com \
/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