From: Lorenzo Campedelli <lorenzo.campedelli@tele2.it>
To: qemu-devel@nongnu.org
Subject: [Qemu-devel] Re: [PATCH] vvfat mbr fixes
Date: Sun, 23 Sep 2007 09:31:20 +0200 [thread overview]
Message-ID: <fd54o8$kjc$1@sea.gmane.org> (raw)
In-Reply-To: <Pine.LNX.4.64.0709222342190.28395@racer.site>
[-- Attachment #1: Type: text/plain, Size: 1710 bytes --]
Johannes Schindelin wrote:
> Hi,
>
> On Sun, 23 Sep 2007, Ivan Kalvachev wrote:
>
>> I've been having problems using vvfat virtual block device. Even linux
>> fdisk was able to find problems with it. The reason turned out to be
>> simple, MBR have bogus parameters.
>
> Thanks for doing this; I did not find any time for that.
>
> Overall, I like what you did, but here are some comments (if you would
> have inlined the patch, I would have commented with references):
>
> - I like the convert_sector2CHS() function, although I would have named it
> sector2CHS() for brevity (although the pretty magic -- or unintuitive
> -- detection if lba is needed would have to be done differently, which
> I maintain would be better),
>
> - you write the NT-ID byte-per-byte, whereas I would have used strcpy()
> for clarity,
>
> - I'd have introduced a member nt_id instead of hardcoding an offset into
> the "ignored" part, and
>
> - fat_type == 12 and lba does not make sense, or does it?
>
> Thanks,
> Dscho
While you are working on vvfat issues, could you give a look to the
attached small patch?
It tries to fix the problem with using vvfat together with -snapshot.
The patch is not complete (it doesn't fix additional options such as
:rw:, :floppy: :32: etc,) nor clean (I guess this specific code should
be in block-vvfat.c, not in block.c, but the backing file handling is
done there...) but I needed a quick fix for my needs.
If anybody has suggestions on how to make a better patch to be
integrated in CVS I'd be glad :)
While I'm here I'd add a related question: wouldn't it be useful to be
able to specify a per-device "-snapshot" option? Is it doable?
Thanks,
Lorenzo
[-- Attachment #2: qemu-0.9.0.20070921-block.c.patch --]
[-- Type: text/x-patch, Size: 1241 bytes --]
--- qemu-0.9.0.20070921/block.c.orig 2007-09-21 21:10:53.000000000 +0200
+++ qemu-0.9.0.20070921/block.c 2007-09-22 10:09:32.000000000 +0200
@@ -331,6 +331,7 @@
if (flags & BDRV_O_SNAPSHOT) {
BlockDriverState *bs1;
+ BlockDriver *drv1;
int64_t total_size;
/* if snapshot, we create a temporary backing file and open it
@@ -346,10 +347,22 @@
return -1;
}
total_size = bdrv_getlength(bs1) >> SECTOR_BITS;
+ drv1 = bs1->drv;
bdrv_delete(bs1);
get_tmp_filename(tmp_filename, sizeof(tmp_filename));
- realpath(filename, backing_filename);
+ /*
+ * for vvfat protocol the string "fat:<options>:" should remain
+ * the prefix of the filename even after realpath() call ...
+ */
+ if (drv1 == &bdrv_vvfat) {
+ int i = strrchr(filename, ':') - filename + 1;
+
+ strncpy(backing_filename, filename, i);
+ realpath(filename + i, backing_filename + i);
+ } else {
+ realpath(filename, backing_filename);
+ }
if (bdrv_create(&bdrv_qcow2, tmp_filename,
total_size, backing_filename, 0) < 0) {
return -1;
next prev parent reply other threads:[~2007-09-23 7:31 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-09-22 21:43 [Qemu-devel] [PATCH] vvfat mbr fixes Ivan Kalvachev
2007-09-22 22:48 ` Johannes Schindelin
2007-09-23 7:31 ` Lorenzo Campedelli [this message]
2007-09-23 11:34 ` [Qemu-devel] " Johannes Schindelin
2007-09-23 15:55 ` Lorenzo Campedelli
2007-09-23 19:18 ` Johannes Schindelin
2007-09-23 20:17 ` Lorenzo Campedelli
2007-09-24 10:50 ` [Qemu-devel] " Ivan Kalvachev
2007-09-24 11:18 ` Johannes Schindelin
2007-09-24 14:12 ` Ivan Kalvachev
2007-09-24 15:32 ` Johannes Schindelin
2007-09-24 17:23 ` Ivan Kalvachev
2007-09-24 19:19 ` [Qemu-devel] " Lorenzo Campedelli
2007-09-24 21:58 ` Johannes Schindelin
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='fd54o8$kjc$1@sea.gmane.org' \
--to=lorenzo.campedelli@tele2.it \
--cc=qemu-devel@nongnu.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).