From: Markus Armbruster <armbru@redhat.com>
To: Juan Quintela <quintela@redhat.com>
Cc: qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [PATCH v2] qemu_file: use fwrite() correctly
Date: Tue, 18 Feb 2014 17:39:58 +0100 [thread overview]
Message-ID: <87ob24qsrl.fsf@blackfin.pond.sub.org> (raw)
In-Reply-To: <1392163249-6983-1-git-send-email-quintela@redhat.com> (Juan Quintela's message of "Wed, 12 Feb 2014 01:00:49 +0100")
Juan Quintela <quintela@redhat.com> writes:
> fwrite() returns the number of items written. But when there is one
> error, it can return a short write.
>
> In the particular bug that I was tracking, I did a migration to a
> read-only filesystem. And it was able to finish the migration
> correctly. fwrite() never returned a negative error code, the 1st
> time it returns 0, after that it returns 4096. (migration writes
> chunks of about 14000 bytes). And it was able to "complete" the
> migration with success (yes, reading the file was a bit more
> difficult). On the 1st fwrite() for the read-only filesystem,
> it returns an errno of -EPIPE, that is exactly what has failed.
>
> To add insult to injury, if your amount of memory was big enough (12GB
> on my case), it overwrote some important structure, and from them,
> malloc failed. This check makes the problem go away.
>
> Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
next prev parent reply other threads:[~2014-02-18 16:57 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-02-12 0:00 [Qemu-devel] [PATCH v2] qemu_file: use fwrite() correctly Juan Quintela
2014-02-18 16:11 ` Eric Blake
2014-02-18 16:39 ` Markus Armbruster [this message]
2014-02-27 7:58 ` Markus Armbruster
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=87ob24qsrl.fsf@blackfin.pond.sub.org \
--to=armbru@redhat.com \
--cc=qemu-devel@nongnu.org \
--cc=quintela@redhat.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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.