Can't unmount UUID= volume as a user

[Jeremy Kerr]

I have the following entry in /etc/fstab:

UUID=00a1665a-f7f1-48c6-8dff-65e77c98bd2f /media/extdisk ext3 user,noauto,exec 0 0

- to allow a nonprivileged user (ie, me) to mount a firewire disk with the specified UUID.

mounting works fine, but unmounting (as the same user) doesn't:

[jk@pokey ~]$ umount /media/extdisk
umount: /media/extdisk mount disagrees with the fstab

When this disk is mounted, /proc/mounts shows:
/dev/disk/by-uuid/00a1665a-f7f1-48c6-8dff-65e77c98bd2f /media/extdisk ext3 rw,nosuid,nodev,data=ordered 0 0

however, /etc/mtab shows:
/dev/sda1 /media/extdisk ext3 rw,nosuid,nodev,user=jk 0 0

If I strace the umount:

[jk@pokey ~]$ sudo strace -etrace=file -u jk umount /media/extdisk/
execve("/bin/umount", ["umount", "/media/extdisk/"], [/* 31 vars */]) = 0
access("/etc/suid-debug", F_OK) = -1 ENOENT (No such file or directory)
access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory)
open("/etc/ld.so.cache", O_RDONLY) = 3
access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
open("/lib/libc.so.6", O_RDONLY) = 3
readlink("/media", 0x7fa625fb, 4096) = -1 EINVAL (Invalid argument)
readlink("/media/extdisk", 0x7fa625fb, 4096) = -1 EINVAL (Invalid argument)
open("/etc/mtab", O_RDONLY|O_LARGEFILE) = 3
open("/etc/fstab", O_RDONLY|O_LARGEFILE) = 3
readlink("/dev", 0x7fa625cb, 4096) = -1 EINVAL (Invalid argument)
readlink("/dev/sda1", 0x7fa625cb, 4096) = -1 EINVAL (Invalid argument)
readlink("/proc", 0x7fa625cb, 4096) = -1 EINVAL (Invalid argument)
readlink("/home", 0x7fa625cb, 4096) = -1 EINVAL (Invalid argument)
readlink("/media", 0x7fa625cb, 4096) = -1 EINVAL (Invalid argument)
readlink("/media/cdrom0", 0x7fa625cb, 4096) = -1 EINVAL (Invalid argument)
getcwd("/home/jk", 4095) = 9
readlink("/home/jk/UUID=00a1665a-f7f1-48c6-8dff-65e77c98bd2f", 0x7fa625cb, 4096) = -1 ENOENT (No such file or directory)
readlink("/media", 0x7fa625cb, 4096) = -1 EINVAL (Invalid argument)
readlink("/media/ipod", 0x7fa625cb, 4096) = -1 EINVAL (Invalid argument)
readlink("/home", 0x7fa625cb, 4096) = -1 EINVAL (Invalid argument)
readlink("/media", 0x7fa625cb, 4096) = -1 EINVAL (Invalid argument)
readlink("/media/ipod", 0x7fa625cb, 4096) = -1 EINVAL (Invalid argument)
readlink("/dev", 0x7fa625cb, 4096) = -1 EINVAL (Invalid argument)
readlink("/dev/disk", 0x7fa625cb, 4096) = -1 EINVAL (Invalid argument)
readlink("/dev/disk/by-uuid", 0x7fa625cb, 4096) = -1 EINVAL (Invalid argument)
readlink("/dev/disk/by-uuid/00bcb37c-0d82-4fc4-9515-9c7daa72ffaf", "../../hda5", 4096) = 10
readlink("/dev/hda5", 0x7fa625cb, 4096) = -1 EINVAL (Invalid argument)
readlink("/dev", 0x7fa625cb, 4096) = -1 EINVAL (Invalid argument)
readlink("/dev/disk", 0x7fa625cb, 4096) = -1 EINVAL (Invalid argument)
readlink("/dev/disk/by-uuid", 0x7fa625cb, 4096) = -1 EINVAL (Invalid argument)
readlink("/dev/disk/by-uuid/27a00a33-2101-44b2-b29f-0be7258b70e7", "../../hda6", 4096) = 10
readlink("/dev/hda6", 0x7fa625cb, 4096) = -1 EINVAL (Invalid argument)
readlink("/dev", 0x7fa625cb, 4096) = -1 EINVAL (Invalid argument)
readlink("/dev/disk", 0x7fa625cb, 4096) = -1 EINVAL (Invalid argument)
readlink("/dev/disk/by-uuid", 0x7fa625cb, 4096) = -1 EINVAL (Invalid argument)
readlink("/dev/disk/by-uuid/883a4c5f-3d9b-4ce4-bf3d-c2d187870e76", "../../hda4", 4096) = 10
readlink("/dev/hda4", 0x7fa625cb, 4096) = -1 EINVAL (Invalid argument)
readlink("/dev", 0x7fa625cb, 4096) = -1 EINVAL (Invalid argument)
readlink("/dev/hdc", 0x7fa625cb, 4096) = -1 EINVAL (Invalid argument)
readlink("/dev", 0x7fa625cb, 4096) = -1 EINVAL (Invalid argument)
readlink("/dev/disk", 0x7fa625cb, 4096) = -1 EINVAL (Invalid argument)
readlink("/dev/disk/by-uuid", 0x7fa625cb, 4096) = -1 EINVAL (Invalid argument)
readlink("/dev/disk/by-uuid/00a1665a-f7f1-48c6-8dff-65e77c98bd2f", "../../sda1", 4096) = 10
readlink("/dev/sda1", 0x7fa625cb, 4096) = -1 EINVAL (Invalid argument)
readlink("/dev", 0x7fa625cb, 4096) = -1 EINVAL (Invalid argument)
readlink("/dev/disk", 0x7fa625cb, 4096) = -1 EINVAL (Invalid argument)
readlink("/dev/disk/by-label", 0x7fa625cb, 4096) = -1 EINVAL (Invalid argument)
readlink("/dev/disk/by-label/IPOD", 0x7fa625cb, 4096) = -1 ENOENT (No such file or directory)
umount: /media/extdisk mount disagrees with the fstab
Process 10417 detached

- umount has managed to resolve the symlink from /dev/disk/by-uuid/00... to /dev/sda1, but hasn't recognised that it's the same device ?

[Brian Pitts (bpitts)]

I can confirm this bug.

# /dev/hda6
UUID=4386-3B67 /media/backup vfat defaults,noauto,utf8,umask=007,gid=46,user,noauto 0 1

mount /media/backup

in /proc/mounts
/dev/disk/by-uuid/4386-3B67 /media/backup vfat rw,nosuid,nodev,noexec,uid=1000,gid=46,fmask=0007,dmask=0007,codepage=cp437,iocharset=iso8859-1,utf8 0 0

in /etc/mtab
/dev/hda6 /media/backup vfat rw,noexec,nosuid,nodev,utf8,umask=007,gid=46,user=brian 0 0

umount /media/backup
umount: /media/backup mount disagrees with the fstab

strace umount /media/backup
execve("/bin/umount", ["umount", "/media/backup"], [/* 31 vars */]) = 0
brk(0) = 0x805b000
access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0xb7f91000
access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory)
open("/etc/ld.so.cache", O_RDONLY) = 3
fstat64(3, {st_mode=S_IFREG|0644, st_size=50023, ...}) = 0
mmap2(NULL, 50023, PROT_READ, MAP_PRIVATE, 3, 0) = 0xb7f84000
close(3) = 0
access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
open("/lib/tls/i686/cmov/libc.so.6", O_RDONLY) = 3
read(3, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0\3\0\1\0\0\0\20Z\1\000"..., 512) = 512
fstat64(3, {st_mode=S_IFREG|0755, st_size=1248904, ...}) = 0
mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0xb7f83000
mmap2(NULL, 1258876, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0xb7e4f000
mmap2(0xb7f7c000, 16384, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x12c) = 0xb7f7c000
mmap2(0xb7f80000, 9596, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0xb7f80000
close(3) = 0
mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0xb7e4e000
set_thread_area({entry_number:-1 -> 6, base_addr:0xb7e4e6b0, limit:1048575, seg_32bit:1, contents:0, read_exec_only:0, limit_in_pages:1, seg_not_present:0, useable:1}) = 0
mprotect(0xb7f7c000, 8192, PROT_READ) = 0
munmap(0xb7f84000, 50023) = 0
brk(0) = 0x805b000
brk(0x807c000) = 0x807c000
...
close(3) = 0
umask(022) = 022
getuid32() = 1000
geteuid32() = 1000
readlink("/media", 0xbf8ad037, 4096) = -1 EINVAL (Invalid argument)
readlink("/media/backup", 0xbf8ad037, 4096) = -1 EINVAL (Invalid argument)
umask(077) = 022
open("/etc/mtab", O_RDONLY|O_LARGEFILE) = 3
umask(022) = 077
fstat64(3, {st_mode=S_IFREG|0644, st_size=623, ...}) = 0
mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0xb7d3f000
read(3, "/dev/hdb1 / ext3 rw,errors=remou"..., 4096) = 623
read(3, "", 4096) = 0
close(3) = 0
munmap(0xb7d3f000, 4096) = 0
stat64("/sbin/umount.vfat", 0xbf8aef6c) = -1 ENOENT (No such file or directory)
oldumount("/media/backup") = -1 E...

[wiertel (wiertel)]

I've encountered the same problem when I tried to unmount /mnt/win with nautilus.

UUID=ACB84F65B84F2D60 /mnt/win ntfs nls=utf8,ro,users,uid=1000 0 0

[lknfdskjy76 (cfer45ysd)]

i can confirm this bug.. its very annoying, someone please fix it

[wiertel (wiertel)]

I've found the reason for this behavior. Here is a patch which correct it.
Patch is most probably incomplete. I have no idea what is blkid or libvolume_id but it works.

[Júlio Alexandrino (alexandrino)]

This bug is probably linked to this one:

https://bugs.launchpad.net/ubuntu/+source/util-linux/+bug/99437

[Júlio Alexandrino (alexandrino)]

... and with Bug #94848

[Frederick Reeve (cylix)]

All three bugs on this are from the same source. This is the fix. I am attaching this patch to all three. I have been using it for a while, its fine. The attached patch should be applied to the src-dep of util-linux. For those of you who want this fix now follow these instructions:

Modify your source.list so you have so the dep-src for the main repository enabled and copy the patch into /tmp. Then run the following commands:

$ sudo apt-get update
$ sudo apt-get install build-essential
$ sudo apt-get build-dep mount
$ cd /tmp
$ apt-get source mount
$ cd util-linux-2.12r
$ ./debian/rules patch
$ patch -Np1 -i ../util-linux_user_mount.patch
$ ./configure
$ make lib
$ make -C mount
$ sudo chown root:root mount/umount
$ sudo chmod 4755 mount/umount
$ sudo mv mount/umount /bin

now you should be able to unmount you drive that was user mounted using a uuid.

[yakrider (yakrider)]

Awesome. It works. Kudos for the good work. My appreciation and wishing godspeed.

[Andrew Davis (papyromancer)]

Great Work!

[Stefan Fleiter (stefan-fleiter)]

This seems to be fixed in gutsy.