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Date: Wed, 20 Jan 2010 18:05:10 +0100
From: Christoph Hellwig <hch@lst.de>
Subject: Re: [Qemu-devel] [PATCH v2 0/4] Modifications to the drives' readonly
	attribute
Message-ID: <20100120170510.GA8444@lst.de>
References: <1263739695-13043-1-git-send-email-nsprei@redhat.com>
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To: Naphtali Sprei <nsprei@redhat.com>
Cc: qemu-devel@nongnu.org

Looking at the version of this that landed in git I don't think the
read-only handling is entirely clean after this.

 - we now normally set the read_only flag from bdrv_open2 when we do
   not have the O_RDWR flag set
 - but the block drivers also mess with it:
   	o raw-posix superflously sets it when BDRV_O_RDWR is not in the
	  open flags
	o bochs, cloop, dmg and parallels set it unconditionally given
	  that they do not support writing at all.  But they do not
	  bother to reject opens without BDRV_O_RDWR
	o vvfat as usual is a complete mess setting and clearing it in
	  various places
 - in addition to that bdrv_open2 also sets it after calling itself for
   the backing hd which seems superflous
 - there also is a now unused bdrv_set_read_only helper to set it from
   outside block.c