fatal mount-problem

Hello all,

If you mount a device like ide-cdrom with the scsi-emulation turned on (as modules) and you do the same mount again on the same (not unmounted) device, the mount-programm hangs up and never comes back. It doesn't recognize, that the device is allready mounted.

If I do a simple "mount", mount lists the /cdrom - device as mounted.

Problem: if you want to unmount the device, mount tells that the device would be bussy and ends. So, you've no chance to unmount the device again. The only way to unmount it, is to do a hardware reset (a normal reboot doesn't work, because mount hangs at the cdrom-device).

Kernel 2.4.9 is working fine.

mount: mount-2.11h

Regards,
Andreas Hartmann

strace, please. -ac5 and 2.4.9 have the same code in fs/super.c, so I really wonder what the hell is happening...

Duplicated here with 2.4.8-ac6
Booted with ide-scsi as the cd driver

mount /dev/scd0 /mnt
umount /dev/scs0
mount /dev/scd0 /mnt
umount /dev/scd0

works fine

mount /dev/scd0 /mnt
mount /dev/scd0 /mmt

hangs (D state)

mount /dev/scd0 /mnt
mount /dev/scd0 /tmp

hangs (D state)

Aha. They actually don't (sorry - I was thinking of 2.4.7-ac5), but...

I can't reproduce it with /dev/hda and /dev/hdd (ide-disk and ide-cd resp.) here. I'll build kernel with ide-scsi and see what's going on with that.

andreas@athlon:~ > mount
/dev/hda1 on / type reiserfs (rw)
proc on /proc type proc (rw)
/dev/hda6 on /opt type reiserfs (rw)
/dev/hda9 on /usr type reiserfs (rw)
/dev/hda8 on /Daten type reiserfs (rw) /dev/hda7 on /home type reiserfs (rw)
/dev/hda5 on /var type reiserfs (rw)
none on /dev/pts type devpts (rw,gid=5,mode=620) tmpfs on /dev/shm type tmpfs (rw)
/dev/sr1 on /cdrom type iso9660 (ro,noexec,nosuid,nodev)

Now the strace after /cdrom has allready been mounted (with ide-scsi turned on)

145   execve("/bin/mount", ["mount", "/cdrom"], [/* 54 vars */]) = 0
145   uname({sys="Linux", node="athlon", ...}) = 0
145   brk(0)                            = 0x8057840
145   shmat(0, 0x400151b8, 0x1)         = ?
145   shmat(1, 0x400151b8, 0x1)         = 0xbffff424
145   shmat(2, 0x400151b8, 0x1)         = ?
145   access("/etc/suid-debug", F_OK)   = -1 ENOENT (No such file or
directory)
145   open("/etc/ld.so.preload", O_RDONLY) = -1 ENOENT (No such file or
directory)
145   open("/etc/ld.so.cache", O_RDONLY) = 4
145   SYS_197(0x4, 0xbfffebe4, 0x40014f40, 0x40015164, 0x4) = 0
145   mmap(NULL, 62282, PROT_READ, MAP_PRIVATE, 4, 0) = 0x40016000
145   close(4)                          = 0
145   open("/lib/libc.so.6", O_RDONLY)  = 4
145   read(4,

"\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0\3\0\1\0\0\0X\331\1"..., 1024) = 1024
145 SYS_197(0x4, 0xbfffec2c, 0x40014f40, 0x40015164, 0x4) = 0
145 mmap(NULL, 1195044, PROT_READ|PROT_EXEC, MAP_PRIVATE, 4, 0) =
0x40026000
145 mprotect(0x40140000, 39972, PROT_NONE) = 0
145 mmap(0x40140000, 24576, PROT_READ|PROT_WRITE,
MAP_PRIVATE|MAP_FIXED, 4, 0x119000) = 0x40140000
145 mmap(0x40146000, 15396, PROT_READ|PROT_WRITE,
MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x40146000

145   close(4)                          = 0
145   munmap(0x40016000, 62282)         = 0
145   brk(0)                            = 0x8057840
145   brk(0x8057860)                    = 0x8057860
145   brk(0x8058000)                    = 0x8058000
145   open("/share/locale/locale.alias", O_RDONLY) = 4
145   SYS_197(0x4, 0xbfffb414, 0x40145a60, 0x4014942c, 0x4) = 0
145   mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS,
-1, 0) = 0x40016000
145   read(4, "# Locale name alias data base.\n#"..., 4096) = 2601
145   brk(0x8059000)                    = 0x8059000
145   read(4, "", 4096)                 = 0
145   close(4)                          = 0
145   munmap(0x40016000, 4096)          = 0
145   open("/lib/locale/de_DE/LC_IDENTIFICATION", O_RDONLY) = -1 ENOENT
(No such file or directory)
145   open("/lib/locale/de/LC_IDENTIFICATION", O_RDONLY) = -1 ENOENT (No
such file or directory)
145   open("/dev/null", O_RDWR|O_LARGEFILE) = 4
145   close(4)                          = 0
145   SYS_199(0x40144d40, 0x2, 0x40145a60, 0x40143490, 0xbffff898) =

1001
145 semop(0x40144d40, 0x2, 0x40145a60, 0x40143490) = 0
145 SYS_196(0x8053c40, 0xbffff79c, 0x40145a60, 0x4014942c, 0x8053c40)
= 0
145 brk(0x805b000) = 0x805b000
145 readlink("/cdrom", 0xbfffe7dc, 4095) = -1 EINVAL (Invalid
argument)

145   open("/etc/fstab", O_RDONLY|O_LARGEFILE) = 4
145   SYS_197(0x4, 0xbffff588, 0x40145a60, 0x4014942c, 0x4) = 0
145   mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS,
-1, 0) = 0x40016000
145   read(4, "/dev/hda2       /boot           "..., 4096) = 1702
145   read(4, "", 4096)                 = 0
145   close(4)                          = 0
145   munmap(0x40016000, 4096)          = 0
145   SYS_195(0xbffff670, 0xbffff610, 0x40145a60, 0x4014942c,

0xbffff670) = -1 ENOENT (No such file or directory)
145 rt_sigprocmask(SIG_BLOCK, ~[TRAP SEGV], NULL, 8) = 0
145 SYS_195(0x8059bb8, 0xbfffe3b0, 0x40145a60, 0x4014942c, 0x8059bb8)
= 0

145   open("/dev/sr1", O_RDONLY|O_LARGEFILE) = 4
145   _llseek(4, 1024, [1024], SEEK_SET) = 0
145   read(4,

"\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 228) = 228
145 _llseek(4, 65536, [65536], SEEK_SET) = 0
145 read(4,
"~\0\301\360\0\0\0\0\360\301K\7\t\0\0\t\7Ke\5\20\2\25;\10"..., 228) = 228
145 _llseek(4, 8192, [8192], SEEK_SET) = 0
145 read(4,
"\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 228) = 228
145 _llseek(4, 0, [0], SEEK_SET) = 0
145 read(4,
"\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 576) = 576
145 _llseek(4, 8192, [8192], SEEK_SET) = 0
145 read(4,
"\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 1376) = 1376

145   _llseek(4, 32768, [32768], SEEK_SET) = 0
145   read(4, "\1CD001\1\0LINUX                   "..., 2048) = 2048
145   close(4)                          = 0
145   mount("/dev/sr1", "/cdrom", "iso9660",

MS_RDONLY|MS_NOSUID|MS_NODEV|MS_NOEXEC|0xc0ed0000, 0x8059c18

sorry, but I couldn't get any more output.

Regards,
Andreas Hartmann

Alan, please apply. sync_dev() in ->release() is 100% bogus - all flushing the stuff out is done by callers (blkdev_close() et.al.).

@@ -101,7 +101,6 @@
 {
 	if (scsi_CDs[MINOR(cdi->dev)].device->sector_size > 2048)
 		sr_set_blocklength(MINOR(cdi->dev), 2048);
-	sync_dev(cdi->dev);
 	scsi_CDs[MINOR(cdi->dev)].device->access_count--;
 	if (scsi_CDs[MINOR(cdi->dev)].device->host->hostt->module)
 		__MOD_DEC_USE_COUNT(scsi_CDs[MINOR(cdi->dev)].device->host->hostt->module);

[...]

It's working fine in 2.4.8ac8 :-) .

Thank you very much!

Regards,
Andreas Hartmann

On a plain vanilla 2.4.7 using ide-scsi driver it works okay on the double mount, and returns device busy. It will however segfault if you try to mount scd0 with no media in the drive.

Cordially,
Mike Hobgood