Panic with msdosfs vs 1.3TB FAT32

[Mario Sergio Fujikawa Ferreira]

Hi,

	I mounted a 1.3TB FAT32 (32k cluster) filesystem on esata
/dev/ada4s1 under /media/esata/ with the '-l' (large option).

	I tried to create a directory and files but got errors:

------

g_vfs_done():ada4s1[WRITE(offset=-980247646208, length=32768)]error = 5
g_vfs_done():ada4s1[WRITE(offset=-980247646208, length=32768)]error = 5
g_vfs_done():ada4s1[WRITE(offset=-980247613440, length=32768)]error = 5
g_vfs_done():ada4s1[WRITE(offset=-980247646208, length=32768)]error = 5
g_vfs_done():ada4s1[WRITE(offset=-980247613440, length=32768)]error = 5
g_vfs_done():ada4s1[WRITE(offset=-980247580672, length=32768)]error = 5
g_vfs_done():ada4s1[WRITE(offset=-980247646208, length=32768)]error = 5
g_vfs_done():ada4s1[WRITE(offset=-980247613440, length=32768)]error = 5
g_vfs_done():ada4s1[WRITE(offset=-980247580672, length=32768)]error = 5
g_vfs_done():ada4s1[WRITE(offset=-980247646208, length=32768)]error = 5
g_vfs_done():ada4s1[WRITE(offset=-980247613440, length=32768)]error = 5
g_vfs_done():ada4s1[WRITE(offset=-980247580672, length=32768)]error = 5

------

	Then, I tried unmounting the filesystem which resulted on

------

fsync: giving up on dirty
0xffffff01bad6e1d8: tag devfs, type VCHR
    usecount 1, writecount 0, refcount 38253 mountedhere 0xffffff00ac899600
    flags ()
    v_object 0xffffff008b839ca8 ref 0 pages 44786
    lock type devfs: EXCL by thread 0xffffff016506cba0 (pid 76462)
        dev ada4s1
g_vfs_done():ada4s1[WRITE(offset=-980247646208, length=32768)]error = 5
g_vfs_done():ada4s1[WRITE(offset=-980247613440, length=32768)]error = 5
g_vfs_done():ada4s1[WRITE(offset=-980247580672, length=32768)]error = 5
fsync: giving up on dirty
0xffffff01bad6e1d8: tag devfs, type VCHR
    usecount 1, writecount 0, refcount 38253 mountedhere 0xffffff00ac899600
    flags ()
    v_object 0xffffff008b839ca8 ref 0 pages 44786
    lock type devfs: UNLOCKED
        dev ada4s1

Fatal trap 12: page fault while in kernel mode
cpuid = 1; apic id = 01
fault virtual address   = 0x4
fault code              = supervisor read data, page not present
instruction pointer     = 0x20:0xffffffff803e60e4
stack pointer           = 0x28:0xffffff80e79ba860
frame pointer           = 0x28:0xffffff80e79ba8a0
code segment            = base 0x0, limit 0xfffff, type 0x1b
                        = DPL 0, pres 1, long 1, def32 0, gran 1
processor eflags        = interrupt enabled, resume, IOPL = 0
current process         = 25 (syncer)

------

	The filesystem is clean since I find no errors under Windows
('chkdsk /f').

	I can otherwise mount, read and write on smaller FAT32
filesystems.  I think there might be a problem with the handling
of such a big FAT32 filesystem.

	A complete textdump is available at

http://people.freebsd.org/~lioux/panic/2010100500/textdump.tar.2

	Is this kind of error expected? Is there anything I can do
to help?

	I can reproduce this error with the 1.3TB fs easily.

	Regards,

-- 
Mario S F Ferreira - DF - Brazil - "I guess this is a signature."
feature, n: a documented bug | bug, n: an undocumented feature