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Bug#459703: marked as done (Incorrect modification time on image files mounted with loopback-devices)

Your message dated 
with message-id 
and subject line Closing this bug
has caused the Debian Bug report #459703,
regarding Incorrect modification time on image files mounted with loopback-devices
to be marked as done.

This means that you claim that the problem has been dealt with.
If this is not the case it is now your responsibility to reopen the
Bug report if necessary, and/or fix the problem forthwith.

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-- 
459703: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=459703
Debian Bug Tracking System
Contact owner@bugs.debian.org with problems
--- Begin Message --- 
Package: mount
Version: 2.13-8
Debian Version: testing

In cooperation with the kernels loopback device driver, losetup doesn't handle 
then timestamps of image files correctly.
If an image file, which is mounted via a loopback device is changed, the 
modification timestamp of the related image file stays constant:

Example:

Create an image file with a file system, mount it and make some content:

mkdir mnt
dd if=/dev/zero of=test.img count=1440 bs=1024
losetup --help
losetup --help /dev/loop0 test.img 
losetup  /dev/loop0 test.img 
mkfs.vfat /dev/loop0
mount /dev/loop0 mnt
touch mnt/test1
umount mnt
losetup -d /dev/loop0

See timestamps:

stat test.img 
File: »test.img«
Size: 1474560         Blocks: 2888       IO Block: 4096   reguläre Datei
Device: 302h/770d       Inode: 5473079     Links: 1
Access: (0644/-rw-r--r--)  Uid: (    0/    root)   Gid: (    0/    root)
Access: 2008-01-08 07:44:05.000000000 +0100
Modify: 2008-01-08 07:42:58.000000000 +0100
Change: 2008-01-08 07:42:58.000000000 +0100

Mount it again and change the content:

losetup /dev/loop0 test.img 
mount /dev/loop0 mnt
touch mnt/test2
umount mnt
losetup -d /dev/loop0
ls mnt

See timestamps:

stat test.img 
File: »test.img«
Size: 1474560         Blocks: 2888       IO Block: 4096   reguläre Datei
Device: 302h/770d       Inode: 5473079     Links: 1
Access: (0644/-rw-r--r--)  Uid: (    0/    root)   Gid: (    0/    root)
Access: 2008-01-08 07:45:17.000000000 +0100
Modify: 2008-01-08 07:42:58.000000000 +0100
Change: 2008-01-08 07:42:58.000000000 +0100

****
As you can see, the modification time of the image file stays constant!

****************************
The result of this behavior is, that every backup program, which compares the 
modification times of files to decide which file has to be stored again and 
which not will NOT backup the image file although it has been changed!
****************************

Suggestions:
a) The loopback device driver should update the modification time of the image 
file on every write access.

b) If this is too difficult, the modification time should be updated each time 
an image file is been mounted with rw access rights.


Kind Regards
Matthias Faulstich

--- End Message ---
--- Begin Message --- 
This bug was filed for a very old kernel. If you can reproduce it with
- the current version in unstable/testing
- the latest kernel from buster.backports
please reopen the bug, see https://www.debian.org/Bugs/server-control

--- End Message ---
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