[PATCH] [RFC] isofs: work-around for Rock Ridge+Joliet CDs with empty ISO root directory

[PATCH] [RFC] isofs: work-around for Rock Ridge+Joliet CDs with empty ISO root directory

[Ondrej Zary]

If a CD has both Rock Ridge and Joliet extensions and the ISO root directory
is empty, no files are visible. Disable Rock Ridge extensions in this case and
use Joliet root directory instead.

Signed-off-by: Ondrej Zary <linux@rainbow-software.org>

--- linux-2.6.35-rc2/fs/isofs/inode.c	2010-06-06 05:43:24.000000000 +0200
+++ linux-2.6.35-rc3/fs/isofs/inode.c	2010-08-24 22:43:26.000000000 +0200
@@ -549,6 +549,34 @@ static unsigned int isofs_get_last_sessi
 }
 
 /*
+ * Check if root directory is empty (has less than 3 files).
+ *
+ * Used to detect broken CDs where ISO root directory is empty but Joliet root
+ * directory is OK. If such CD has Rock Ridge extensions, they will be disabled
+ * (and Joliet used instead) or else no files would be visible.
+ */
+static bool rootdir_empty(struct super_block *sb, unsigned long block)
+{
+	int offset, files, de_len;
+	struct iso_directory_record *de;
+	struct buffer_head *bh;
+
+	bh = sb_bread(sb, block);
+	if (!bh)
+		return true;
+	while (files < 3) {
+		de = (struct iso_directory_record *) (bh->b_data + offset);
+		de_len = *(unsigned char *) de;
+		if (de_len == 0)
+			break;
+		files++;
+		offset += de_len;
+	}
+	brelse(bh);
+	return files < 3;
+}
+
+/*
  * Initialize the superblock and read the root inode.
  *
  * Note: a check_disk_change() has been done immediately prior
@@ -842,6 +870,18 @@ root_found:
 		goto out_no_root;
 
 	/*
+	 * Fix for broken CDs with Rock Ridge and empty ISO root directory but
+	 * correct Joliet root directory.
+	 */
+	if (sbi->s_rock == 1 && joliet_level &&
+				rootdir_empty(s, sbi->s_firstdatazone)) {
+		printk(KERN_NOTICE
+			"ISOFS: primary root directory is empty. "
+			"Disabling Rock Ridge and switching to Joliet.");
+		sbi->s_rock = 0;
+	}
+
+	/*
 	 * If this disk has both Rock Ridge and Joliet on it, then we
 	 * want to use Rock Ridge by default.  This can be overridden
 	 * by using the norock mount option.  There is still one other



-- 
Ondrej Zary

unable to mount a CD - iso9660 bug?

[Ondrej Zary]

Hello,
I have a CD that came with Samsung printer that Linux cannot mount but works 
fine in Windows. The CD is physically OK - "dd" made ISO image without any 
problems. This ISO image is unmountable too. When I force the filesystem to 
iso9660, it mounts but no files are visible:

# mount samsung-bad.iso /mnt/tmp -o loop
mount: you must specify the filesystem type
# mount samsung-bad.iso /mnt/tmp -o loop -t iso9660
# ls -la /mnt/tmp
total 6
dr-xr-xr-x  2 root root 2048 Oct 30  2009 .
drwxr-xr-x 15 root root 4096 Sep 26  2006 ..
# df -h /mnt/tmp
Filesystem            Size  Used Avail Use% Mounted on
/dev/loop0            232M  232M     0 100% /mnt/tmp

dmesg shows this:
ISO 9660 Extensions: Microsoft Joliet Level 3
ISO 9660 Extensions: RRIP_1991A


If anyone can look into this, I can provide a link to the compressed ISO file 
(75MB).

-- 
Ondrej Zary

Re: unable to mount a CD - iso9660 bug?

[A. C. Censi]

On Tue, Aug 17, 2010 at 7:08 AM, Ondrej Zary <linux@rainbow-software.org> wrote:
> On Tuesday 17 August 2010, Tao Ma wrote:
>> Hi Ondrej
>>
>> On 08/17/2010 12:50 AM, Ondrej Zary wrote:
>> > On Monday 16 August 2010 16:18:57 Ondrej Zary wrote:
>> >> On Monday 16 August 2010, Johannes Stezenbach wrote:
>> >>> On Mon, Aug 16, 2010 at 02:38:54PM +0200, Ondrej Zary wrote:
>> >>>> I have a CD that came with Samsung printer that Linux cannot mount but
>> >>>> works fine in Windows. The CD is physically OK - "dd" made ISO image
>> >>>> without any problems. This ISO image is unmountable too. When I force
>> >>>> the filesystem to iso9660, it mounts but no files are visible:
>> >>>
>> >>> Maybe it's a multi-session disk where the first session is
>> >>> HFS with Apple software.  Try mounting with -t iso9660 -o session=1.
>> >>
>> >> Still the same - no files. dmesg contains:
>> >>
>> >> ISOFS: Invalid session number or type of track
>> >> ISOFS: Invalid session number
>> >> ISO 9660 Extensions: Microsoft Joliet Level 3
>> >> ISO 9660 Extensions: RRIP_1991A
>> >
>> > Here's the compressed ISO file if anyone wants to examine it:
>> > http://www.rainbow-software.org/linux_files/samsung-bad.rar
>>
>> what is your kernel version? I can mount it successfully in my el5 box
>> with kernel 2.6.35+.
>
> I have 2.6.35. Also tried it on another two machines with Debian Squeeze
> 2.6.32 and Lenny 2.6.26 with the same result (no files visible when mounted).
>
>
> --
> Ondrej Zary
> --
> To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>

Try -unide mount option.

If it does not work, try what is described in the last posts of this thread:
http://www.pubbs.net/200910/kernel/12764-iso9660-mount-problem.html

Regards

-- 
A. C. Censi
accensi [em] gmail [ponto] com
accensi [em] montreal [ponto] com [ponto] br
--
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Re: unable to mount a CD - iso9660 bug?

[Ondrej Zary]

On Tuesday 17 August 2010 13:50:39 A. C. Censi wrote:
> On Tue, Aug 17, 2010 at 7:08 AM, Ondrej Zary <linux@rainbow-software.org> 
wrote:
> > On Tuesday 17 August 2010, Tao Ma wrote:
> >> Hi Ondrej
> >>
> >> On 08/17/2010 12:50 AM, Ondrej Zary wrote:
> >> > On Monday 16 August 2010 16:18:57 Ondrej Zary wrote:
> >> >> On Monday 16 August 2010, Johannes Stezenbach wrote:
> >> >>> On Mon, Aug 16, 2010 at 02:38:54PM +0200, Ondrej Zary wrote:
> >> >>>> I have a CD that came with Samsung printer that Linux cannot mount
> >> >>>> but works fine in Windows. The CD is physically OK - "dd" made ISO
> >> >>>> image without any problems. This ISO image is unmountable too. When
> >> >>>> I force the filesystem to iso9660, it mounts but no files are
> >> >>>> visible:
> >> >>>
> >> >>> Maybe it's a multi-session disk where the first session is
> >> >>> HFS with Apple software.  Try mounting with -t iso9660 -o session=1.
> >> >>
> >> >> Still the same - no files. dmesg contains:
> >> >>
> >> >> ISOFS: Invalid session number or type of track
> >> >> ISOFS: Invalid session number
> >> >> ISO 9660 Extensions: Microsoft Joliet Level 3
> >> >> ISO 9660 Extensions: RRIP_1991A
> >> >
> >> > Here's the compressed ISO file if anyone wants to examine it:
> >> > http://www.rainbow-software.org/linux_files/samsung-bad.rar
> >>
> >> what is your kernel version? I can mount it successfully in my el5 box
> >> with kernel 2.6.35+.
> >
> > I have 2.6.35. Also tried it on another two machines with Debian Squeeze
> > 2.6.32 and Lenny 2.6.26 with the same result (no files visible when
> > mounted).
> >
> >
> > --
> > Ondrej Zary
> > --
> > To unsubscribe from this list: send the line "unsubscribe linux-fsdevel"
> > in the body of a message to majordomo@vger.kernel.org
> > More majordomo info at  http://vger.kernel.org/majordomo-info.html
>
> Try -unide mount option.
>
> If it does not work, try what is described in the last posts of this
> thread: http://www.pubbs.net/200910/kernel/12764-iso9660-mount-problem.html

Thanks. As Bodo Eggert said, "-o norock" helps.

In fact, I've hit two "bugs":
1. blkid is unable to recognize HFS+ISO9660 CD. Just tracked it down and fixed 
only to find that it was aleady fixed:
http://git.kernel.org/?p=utils/util-linux-ng/util-linux-ng.git;a=commitdiff;h=791a2fd67c118c3f07141e4cc95532fe908015a9

2. some kernel feature - when Rock Ridge is present on iso9660, it's preferred 
over Joliet. The CD contains both but seems that only Joliet has files 
inside? When it's mounted with "-o nojoliet,norock", it's empty too. Can we 
detect this case and avoid it somehow (switch to Joliet?)

-- 
Ondrej Zary

[PATCH] [RFC] isofs: work-around for Rock Ridge+Joliet CDs with empty ISO root directory

[Ondrej Zary]

If a CD has both Rock Ridge and Joliet extensions and the ISO root directory
is empty, no files are visible. Disable Rock Ridge extensions in this case and
use Joliet root directory instead.

Signed-off-by: Ondrej Zary <linux@rainbow-software.org>

--- linux-2.6.35-rc2/fs/isofs/inode.c	2010-06-06 05:43:24.000000000 +0200
+++ linux-2.6.35-rc3/fs/isofs/inode.c	2010-08-24 22:43:26.000000000 +0200
@@ -549,6 +549,34 @@ static unsigned int isofs_get_last_sessi
 }
 
 /*
+ * Check if root directory is empty (has less than 3 files).
+ *
+ * Used to detect broken CDs where ISO root directory is empty but Joliet root
+ * directory is OK. If such CD has Rock Ridge extensions, they will be disabled
+ * (and Joliet used instead) or else no files would be visible.
+ */
+static bool rootdir_empty(struct super_block *sb, unsigned long block)
+{
+	int offset, files, de_len;
+	struct iso_directory_record *de;
+	struct buffer_head *bh;
+
+	bh = sb_bread(sb, block);
+	if (!bh)
+		return true;
+	while (files < 3) {
+		de = (struct iso_directory_record *) (bh->b_data + offset);
+		de_len = *(unsigned char *) de;
+		if (de_len == 0)
+			break;
+		files++;
+		offset += de_len;
+	}
+	brelse(bh);
+	return files < 3;
+}
+
+/*
  * Initialize the superblock and read the root inode.
  *
  * Note: a check_disk_change() has been done immediately prior
@@ -842,6 +870,18 @@ root_found:
 		goto out_no_root;
 
 	/*
+	 * Fix for broken CDs with Rock Ridge and empty ISO root directory but
+	 * correct Joliet root directory.
+	 */
+	if (sbi->s_rock == 1 && joliet_level &&
+				rootdir_empty(s, sbi->s_firstdatazone)) {
+		printk(KERN_NOTICE
+			"ISOFS: primary root directory is empty. "
+			"Disabling Rock Ridge and switching to Joliet.");
+		sbi->s_rock = 0;
+	}
+
+	/*
 	 * If this disk has both Rock Ridge and Joliet on it, then we
 	 * want to use Rock Ridge by default.  This can be overridden
 	 * by using the norock mount option.  There is still one other



-- 
Ondrej Zary