Re: Error testing ext3 on brd ramdisk

[Nick Piggin <npiggin@suse.de>]

On Tue, Mar 10, 2009 at 05:49:13PM +0100, Jorge Boncompte [DTI2] wrote:
> Nick Piggin escribió:
> >Ah, of course, it would be due to directory-in-pagecache. You need
> >the following patch if you expect this to work.
> >
> >And that confirms the ext3 problem is a different one because it
> >doesn't use directory in pagecache I think. Well, I'll look at
> >that one tomorrow.
> >
> >Thanks,
> >Nick
> >
> >---
> > fs/super.c |    2 ++
> > 1 file changed, 2 insertions(+)
> >
> >Index: linux-2.6/fs/super.c
> >===================================================================
> >--- linux-2.6.orig/fs/super.c
> >+++ linux-2.6/fs/super.c
> >@@ -644,6 +644,8 @@ int do_remount_sb(struct super_block *sb
> > 		acct_auto_close(sb);
> > 	shrink_dcache_sb(sb);
> > 	fsync_super(sb);
> >+	if (flags & MS_RDONLY)
> >+		invalidate_bdev(sb->s_bdev);
> > 
> > 	/* If we are remounting RDONLY and current sb is read/write,
> > 	   make sure there are no rw files opened */
> >
> >
> >
> >
> 
> 	With this applied it seems I cannot reproduce the corruption, I have 

Ah, that sounds promising.

> 	to do more tests, but the box oopses on reboot after doing "umount -na -r".

Oh, silly me, s_bdev will be NULL for non block device based filesystems.
If you check for s_bdev != NULL there too, it should work.

> 
> [  193.073856] BUG: unable to handle kernel NULL pointer dereference at 
> 00000004
> [  193.075762] IP: [<c018baa7>] invalidate_bdev+0x4/0x27
> [  193.078748] *pde = 00000000
> [  193.080306] Oops: 0000 [#1] SMP
> [  193.082066] last sysfs file: 
> /sys/devices/pci0000:00/0000:00:01.3/i2c-adapter/i2c-0/name
> [  193.082066] Modules linked in: atmtcp ipt_REJECT nf_conntrack_ipv4 
> nf_defrag_ipv4 xt_state nf_conntrack iptable_filter ip_tables x_tables 
> i2c_piix4 i2c_core ata_piix libata ppp_async ppp_synctty sha1_generic 
> arc4 ecb ppp_mppe pppol2tp pppoatm pppoe pppox ppp_generic slhc 8021q 
> garp tun softdog usbcore
> [  193.082066]
> [  193.082066] Pid: 1500, comm: busybox Not tainted (2.6.29-rc7 #122)
> [  193.082066] EIP: 0060:[<c018baa7>] EFLAGS: 00010202 CPU: 3
> [  193.082066] EIP is at invalidate_bdev+0x4/0x27
> [  193.082066] EAX: 00000000 EBX: 00000001 ECX: 00000000 EDX: 00000001
> [  193.082066] ESI: ce82dc00 EDI: 00000000 EBP: ce861f30 ESP: ce861f2c
> [  193.082066]  DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068
> [  193.082066] Process busybox (pid: 1500, ti=ce860000 task=ce8c0530 
> task.ti=ce860000)
> [  193.082066] Stack:
> [  193.082066]  00000001 ce861f48 c017408a 00000001 00000001 ce861f78 
> ce82dc00 ce861f64
> [  193.082066]  c0184cd8 00000000 00000040 ce251000 00000001 00000040 
> ce861f8c c01853d5
> [  193.082066]  00000000 00000000 ce518000 cf81f140 cf401f20 00000000 
> ce251000 00000000
> [  193.082066] Call Trace:
> [  193.082066]  [<c017408a>] ? do_remount_sb+0x4b/0xc2
> [  193.082066]  [<c0184cd8>] ? do_remount+0x70/0xb5
> [  193.082066]  [<c01853d5>] ? do_mount+0x107/0x181
> [  193.082066]  [<c0185665>] ? sys_mount+0x6a/0xa6
> [  193.082066]  [<c0102ce2>] ? syscall_call+0x7/0xb
> [  193.082066] Code: 43 c0 e8 d2 74 f9 ff 58 5a 8b 45 ec 83 c0 74 e8 d8 
> fb 1c 00 8b 45 e4 e8 f9 e1 fc ff 8b 45 e8 8d 65 f4 5b 5e 5f 5d c3 55 89 
> e5 53 <8b> 40 04 8b 98 14 01 00 00 83 7b 60 00 74 11 e8 36 0f 00 00 83
> [  193.082066] EIP: [<c018baa7>] invalidate_bdev+0x4/0x27 SS:ESP 
> 0068:ce861f2c
> [  193.132444] ---[ end trace 47b1cfc0707471fd ]---
> [  193.133287] Kernel panic - not syncing: Fatal exception
> [  193.134372] Rebooting in 40 seconds.. 
> 
> 
> -- 
> ==============================================================
> Jorge Boncompte - Ingenieria y Gestion de RED
> DTI2 - Desarrollo de la Tecnologia de las Comunicaciones
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