[linux-lvm] Odd snapshot behavior

[AJ Lewis]

I'm seeing very odd snapshot behavior with Linux 2.4.7 and LVM 0.9.1 Beta8,
and the VFS-lock patch.  Even without the VFS-lock path, ext2 seems to cache
stuff up so the snapshot directory doesn't appear to be disabled for quite a
while.

2.4.7 with LVM 0.9.1 beta8 and VFS-lock patch
---------------------------------------------

ReiserFS
--------

Make LV (500m)
mkreiserfs
mount LV
cp something to it
make snapshot (16m)
mount snapshot
cp enough to LV to fill snapshot
sync
ls to a known directory in snapshot:

kernel BUG at namei.c:343!

Entering kdb (current=0xc5d42000, pid 338) Oops: invalid operand
due to oops @ 0xc8824c68
eax = 0x0000001b ebx = 0xc5d43e50 ecx = 0xc79fe000 edx = 0xc02bd964 
esi = 0xc883e7b0 edi = 0xc5d43ed4 esp = 0xc5d43e38 eip = 0xc8824c68 
ebp = 0xc5d43e68 xss = 0x00000018 xcs = 0x00000010 eflags = 0x00010286 
xds = 0x00000018 xes = 0x00000018 origeax = 0xffffffff &regs = 0xc5d43e04
kdb> bt
    EBP       EIP         Function(args)
0xc5d43e68 0xc8824c68 [reiserfs]reiserfs_find_entry+0x88 (0xc7ec2bc0, 0xc7e34b7c, 0x4, 0xc5d43e94, 0xc5d43ed4)
                               reiserfs .text 0xc8821060 0xc8824be0 0xc8824d24
           0xc8824d90 [reiserfs]reiserfs_lookup+0x6c (0xc7ec2bc0, 0xc7e34b20) 
                               reiserfs .text 0xc8821060 0xc8824d24 0xc8824de8
           0xc0134b98 real_lookup+0x58 (0xc20137e0, 0xc5d43f5c, 0x0)          
                               kernel .text 0xc0100000 0xc0134b40 0xc0134c0c
0xc5d43f68 0xc013525d path_walk+0x541 (0xc124c00c, 0xc5d43fa0)              
                               kernel .text 0xc0100000 0xc0134d1c 0xc0135490
0xc5d43f84 0xc013584c __user_walk+0x3c (0xbffffea8, 0x8, 0xc5d43fa0)        
                               kernel .text 0xc0100000 0xc0135810 0xc013586c
0xc5d43fbc 0xc0132a73 sys_lstat64+0x17 (0xbffffea8, 0x8053774, 0x401368e0, 0x4013a050, 0xbffffea8)
                               kernel .text 0xc0100000 0xc0132a5c 0xc0132acc
           0xc0106b9b system_call+0x33                                      
                               kernel .text 0xc0100000 0xc0106b68 0xc0106ba0


------------------------------------------------------------------------------

ext2
----

Make LV (500m)
mke2fs
mount LV
cp something to it
make snapshot (16m)
mount snapshot
cp enough to LV to fill snapshot
sync
ls to the snapshot mount:

# ls /demo2
boot  lost+found

ls to a known directory in snapshot:

/demo2/boot 
ls: /demo2/boot: Input/output error

-- 
AJ Lewis
Sistina Software Inc.                  Voice:  612-638-0500
1313 5th St SE, Suite 111              Fax:    612-638-0500
Minneapolis, MN 55414                  E-Mail: lewis at sistina.com
http://www.sistina.com

Current GPG fingerprint = 3B5F 6011 5216 76A5 2F6B  52A0 941E 1261 0029 2648
Get my key at: http://www.sistina.com/~lewis/gpgkey
 (Unfortunately, the PKS-type keyservers do not work with multiple sub-keys)

-----Begin Obligatory Humorous Quote----------------------------------------
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