Re: udf: Commit b085fbe2ef7fa (udf: Fix crash during mount) broke CD-RW support

From: "Pali Rohár" <pali.rohar@gmail.com>
To: Jan Kara <jack@suse.cz>
Cc: linux-fsdevel@vger.kernel.org,
	"Steven J. Magnani" <steve.magnani@digidescorp.com>
Subject: Re: udf: Commit b085fbe2ef7fa (udf: Fix crash during mount) broke CD-RW support
Date: Fri, 17 Jan 2020 12:35:37 +0100	[thread overview]
Message-ID: <20200117113537.tvyiz3bictp7p2ki@pali> (raw)
In-Reply-To: <20200117112254.GF17141@quack2.suse.cz>

On Friday 17 January 2020 12:22:54 Jan Kara wrote:
> On Thu 16-01-20 16:46:43, Pali Rohár wrote:
> > On Monday 13 January 2020 12:48:38 Jan Kara wrote:
> > > On Sun 12-01-20 15:47:35, Pali Rohár wrote:
> > > > So I think that UDF 2.60 is clear that for CD-RW medias (formatted in
> > > > normal or MRW mode) should be used Overwritable access type. But all
> > > > mentioned tools were probably written prior to existence of UDF 2.60
> > > > specifications, probably targeting only UDF 1.50 versions at that time.
> > > > 
> > > > I checked that they use Unallocated Space Bitmap (and not Freed Space
> > > > Bitmap), so writing to these filesystems should not be a problem.
> > > > 
> > > > How to handle this situation? UDF 2.01 nor 1.50 does not say anything
> > > > for access type on CD-RW and there are already tools which generates UDF
> > > > 1.50 images which does not matches UDF 2.60 requirements.
> > > > 
> > > > I think that the best would be to relax restrictions added in commit
> > > > b085fbe2ef7fa to allow mounting mounting udf fs with rewritable access
> > > > type in R/W mode if Freed Space Bitmap/Table is not used.
> > > > 
> > > > I'm really not sure if existing udf implementations take CD-RW media
> > > > with overwritable media type. E.g. prehistoric wrudf tool refuse to work
> > > > with optical discs which have overwritable access type. I supports only
> > > > UDF 1.50.
> > > 
> > > Yeah, we should maintain compatibility with older tools where sanely
> > > possible. So I agree with what you propose. Allow writing to
> > > PD_ACCESS_TYPE_REWRITABLE disks if they don't use 'Freed Space
> > > Bitmap/Table'. Will you send a patch or should I do the update?
> > 
> > Could you do it, please?
> 
> Sure, attached.

Looks good, just you have specified wrong MIME enc: charset=iso-8859-1
It should be UTF-8. You can add my Reviewed-by keyword.

-- 
Pali Rohár
pali.rohar@gmail.com