FAT filesystem becomes corrupted

[Joaquin Cuenca Abela]

I have a FAT-32 filesystem on a iBead mp3 usb player.
The filesystem becomes regularly corrupted.
When I try a dosfsck -a on this unit, it shows/fixes several problems, and then
it segfaults.

Output from dmesg:

usb 1-1: new full speed USB device using address 4
scsi1 : SCSI emulation for USB Mass Storage devices
 Vendor: EXATEL Model: i-BEAD100 Rev: 0001
 Type: Direct-Access ANSI SCSI revision: 02
SCSI device sda: 505857 512-byte hdwr sectors (259 MB)
sda: Write Protect is off
sda: Mode Sense: 03 00 00 04
sda: assuming drive cache: write through
/dev/scsi/host1/bus0/target0/lun0: p1
Attached scsi removable disk sda at scsi1, channel 0, id 0, lun 0
USB Mass Storage device found at 4
FAT: Filesystem panic (dev sda1)
   fat_get_cluster: invalid cluster chain (i_pos 0)
   File system has been set read-only
FAT: Filesystem panic (dev sda1)
   fat_get_cluster: invalid cluster chain (i_pos 0)
FAT: Filesystem panic (dev sda1)
   fat_get_cluster: invalid cluster chain (i_pos 0)
FAT: Filesystem panic (dev sda1)
   fat_get_cluster: invalid cluster chain (i_pos 0)
FAT: Filesystem panic (dev sda1)
   fat_get_cluster: invalid cluster chain (i_pos 0)
FAT: Filesystem panic (dev sda1)
   fat_get_cluster: invalid cluster chain (i_pos 0)
FAT: Filesystem panic (dev sda1)
   invalid access to FAT (entry 0x0000ff4b)
FAT: Filesystem panic (dev sda1)
   fat_get_cluster: invalid cluster chain (i_pos 0)
FAT: Filesystem panic (dev sda1)
   fat_get_cluster: invalid cluster chain (i_pos 0)
FAT: Filesystem panic (dev sda1)
   fat_get_cluster: invalid cluster chain (i_pos 0)
FAT: Filesystem panic (dev sda1)
   invalid access to FAT (entry 0x0000f732)
FAT: Filesystem panic (dev sda1)
   fat_get_cluster: invalid cluster chain (i_pos 0)
FAT: Filesystem panic (dev sda1)
   fat_get_cluster: invalid cluster chain (i_pos 0)
FAT: Filesystem panic (dev sda1)
   fat_get_cluster: invalid cluster chain (i_pos 0)
FAT: Filesystem panic (dev sda1)
   invalid access to FAT (entry 0x0000f9f4)
FAT: Filesystem panic (dev sda1)
   fat_get_cluster: invalid cluster chain (i_pos 0)
FAT: Filesystem panic (dev sda1)
   fat_get_cluster: invalid cluster chain (i_pos 0)
FAT: Filesystem panic (dev sda1)
   fat_get_cluster: invalid cluster chain (i_pos 0)
FAT: Filesystem panic (dev sda1)
   fat_get_cluster: invalid cluster chain (i_pos 0)
FAT: Filesystem panic (dev sda1)
   invalid access to FAT (entry 0x0000f722)
FAT: Filesystem panic (dev sda1)
   invalid access to FAT (entry 0x0000ffff)
FAT: Filesystem panic (dev sda1)
   fat_get_cluster: invalid cluster chain (i_pos 0)
FAT: Filesystem panic (dev sda1)
   fat_get_cluster: invalid cluster chain (i_pos 0)
FAT: Filesystem panic (dev sda1)
   fat_get_cluster: invalid cluster chain (i_pos 0)
FAT: Filesystem panic (dev sda1)
   fat_get_cluster: invalid cluster chain (i_pos 0)
FAT: Filesystem panic (dev sda1)
   fat_get_cluster: invalid cluster chain (i_pos 0)
FAT: Filesystem panic (dev sda1)
   fat_get_cluster: invalid cluster chain (i_pos 0)
FAT: Filesystem panic (dev sda1)
   fat_get_cluster: invalid cluster chain (i_pos 0)
FAT: Filesystem panic (dev sda1)
   fat_get_cluster: invalid cluster chain (i_pos 0)
FAT: Filesystem panic (dev sda1)
   fat_get_cluster: invalid cluster chain (i_pos 0)
FAT: Filesystem panic (dev sda1)
   fat_get_cluster: invalid cluster chain (i_pos 0)
FAT: Filesystem panic (dev sda1)
   invalid access to FAT (entry 0x0000ffc2)
FAT: Filesystem panic (dev sda1)
   fat_get_cluster: invalid cluster chain (i_pos 0)
FAT: Filesystem panic (dev sda1)
   fat_get_cluster: invalid cluster chain (i_pos 0)
FAT: Filesystem panic (dev sda1)
   fat_get_cluster: invalid cluster chain (i_pos 0)
FAT: Filesystem panic (dev sda1)
   fat_get_cluster: invalid cluster chain (i_pos 0)
FAT: Filesystem panic (dev sda1)
   fat_get_cluster: invalid cluster chain (i_pos 0)
FAT: Filesystem panic (dev sda1)
   invalid access to FAT (entry 0x0000fc91)
FAT: Filesystem panic (dev sda1)
   fat_get_cluster: invalid cluster chain (i_pos 0)
FAT: Filesystem panic (dev sda1)
   fat_get_cluster: invalid cluster chain (i_pos 0)
FAT: Filesystem panic (dev sda1)
   fat_get_cluster: invalid cluster chain (i_pos 0)
FAT: Filesystem panic (dev sda1)
   fat_get_cluster: invalid cluster chain (i_pos 0)
FAT: Filesystem panic (dev sda1)
   fat_get_cluster: invalid cluster chain (i_pos 0)
FAT: Filesystem panic (dev sda1)
   fat_get_cluster: invalid cluster chain (i_pos 0)
FAT: Filesystem panic (dev sda1)
   fat_get_cluster: invalid cluster chain (i_pos 0)
FAT: Filesystem panic (dev sda1)
   fat_get_cluster: invalid cluster chain (i_pos 0)
usb 1-1: USB disconnect, address 4

[Chuck Short (zulcss)]

Have you tried writing any data to it recently or even re-formatted it?

[Matt Zimmerman (mdz)]

dosfsck seems to have some problems; that's why we don't enable it by default.
I wouldn't necessarily trust its analysis, or its ability to fix problems in the
filesystem.

Perhaps you disconnected the device without unmounting it? This must be avoided
until synchronous I/O to vfat filesystems is implemented (bug #8693)

[Joaquin Cuenca Abela (e98cuenc-yahoo)]

Chuck:

I reformat it regularly. And still this problem keeps coming back.

Matt:

Ok, will not use dosfsck anymore. I religiously unmount the drive each time I
use it. There two more people in my familly that use the unit, and they swear to
also unmount the unit, as I said. But I can't be 100% sure they do it.

I will reformat it again, and make an exclusive use of the unit for some days to
see if this still happens and report my findings.

Thank you,

[Joaquin Cuenca Abela (e98cuenc-yahoo)]

It seems this is due to users not unmount the drive.
Sorry for the noise.

[Matt Zimmerman (mdz)]

It is our intention that unmounting should not be strictly necessary, at least
for FAT filesystems. Resolving as a duplicate appropriately.

This bug has been marked as a duplicate of bug 8693.