[BusyBox 0000498]: mount loop device support broken

[bugs at busybox.net]

A NOTE has been added to this issue. 
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http://busybox.net/bugs/view.php?id=498 
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Reported By:                smiley73
Assigned To:                BusyBox
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Project:                    BusyBox
Issue ID:                   498
Category:                   Other
Reproducibility:            always
Severity:                   major
Priority:                   normal
Status:                     feedback
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Date Submitted:             10-21-2005 20:15 PDT
Last Modified:              11-06-2005 09:12 PST
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Summary:                    mount loop device support broken
Description: 
Starting from some release after 1.0rc1, mounting loop devices (in my case
an ISO image) doesn't work right anymore. Right now I use 1.01
Under Kernel 2.4.31 it seems the mount doesn't find a free loop device and
you have to specife "mount -o loop=/dev/loop ...."
Under Kernel 2.6.13.2 I couldn't get it to work at all. I tried the latest
code from SVN about 3 weeks ago, but it doesn't work either.
Unfortunately I can't give you more information.
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---------------------------------------------------------------------- 
 smiley73 - 10-24-05 06:44  
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I did some further testing and it doesn't seem to be dependend on the
Kernel release.
Modifying the mount command to use "-o loop=/dev/loop0" returns the error
message, that it's not a valid block device.
Setting up the loopback device via losetup before the mount also doesn't
solve the problem.
One test used glibc 2.3.2 (kernel 2.4) and the other glibc 2.3.5 (kernel
2.6).
Both times busybox was statically compiled and used in the InitRD. 

---------------------------------------------------------------------- 
 smiley73 - 10-24-05 10:28  
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Some further testing showed, that busybox 1.00 seems to work fine.
So the error must have been introduced after that.

Heiko 

---------------------------------------------------------------------- 
 landley - 11-03-05 18:00  
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Does it work in 1.1.0-pre1?  This code underwent a major rewrite.  The old
stuff was really brittle and tended to break a lot. 

---------------------------------------------------------------------- 
 smiley73 - 11-06-05 09:12  
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OK I tested with 1.1.0-pre1, I didn't have any luck.

mount -o loop /mnt/bootcd.iso /cdrom
Returns 'could not set up loop device'

losetup /dev/loop0 /mnt/bootcd.iso
Works the first time, but hangs when it's being run a second time.
And yes, I ran "losetup -d /dev/loop0" bfore.
When running losetup the second time, it doesn't matter if you specify a
different  loop device, it always hangs.
It also seems that in most cases when this happens, the loop file (the ISO
image in my case) actually gets damaged and I have to copy it again.

When first setup the loop device via losetup and then try to mount loop0,
then I get the error message: bio too big device loop0 (0 > 2)

Heiko 

Issue History 
Date Modified   Username       Field                    Change               
====================================================================== 
10-21-05 20:15  smiley73       New Issue                                    
10-21-05 20:15  smiley73       Status                   new => assigned     
10-21-05 20:15  smiley73       Assigned To               => BusyBox         
10-24-05 06:44  smiley73       Note Added: 0000640                          
10-24-05 10:28  smiley73       Note Added: 0000641                          
11-02-05 17:15  pschulz01      Issue Monitored: pschulz01                    
11-03-05 18:00  landley        Note Added: 0000656                          
11-03-05 18:00  landley        Status                   assigned => feedback
11-06-05 09:12  smiley73       Note Added: 0000668                          
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