[linux-lvm] Fwd: Re: lvm - lvm_map access beyond end of device
Jeffrey Hundstad
jeffrey.hundstad at mnsu.edu
Fri Mar 9 16:41:28 UTC 2001
Resent after subscribing to your list... original quoted in multiple
replies.
-------- Original Message --------
Subject: Re: lvm - lvm_map access beyond end of device
Date: Thu, 08 Mar 2001 23:01:33 -0600
From: Jeffrey Hundstad <jeffrey.hundstad at mnsu.edu>
Organization: Minnesota State University, Mankato
To: Andreas Dilger <adilger at turbolinux.com>
CC: Linux Kernel Mailing List
<linux-kernel at vger.kernel.org>,linux-lvm at sistina.com
References: <200103090046.f290kV607666 at webber.adilger.net>
Andreas Dilger wrote:
> Jeffrey Hundstad writes:
> > After about 27 days of uptime one of our Linux machines that is being
> > used as a Samba, Netatalk, and FTP server; the main data mount went into
> > a read-only state.
> [snip]
> > We are mounting that 656GB disk as an EXT2 mount on /data.
>
> As an aside, other than this problem, how do you find ext2 on such a large
> filesystem? So far this is the largest ext2 filesystem I've seen. Are
> you looking into ext3 at all to avoid fsck on crash? Granted, in this
> case you still needed to do the whole fsck but in other cases ext3 would
> help.
EXT2 is nice and snappy. This is our first crash... but the fsck was
fun to watch ;) We
might switch if there is a stable alternative. I've used EXT3 on my
personal system and it
worked fine, and it was really sweet to move from EXT2<->EXT3. Do you
recommend it for a
production system? Why isn't it in 2.2.18 OR 2.4.x?
>
> > ...during normal use we got events in our syslog (attached), also note
> > the RAID controller showed no events. After a umount of the mounted
> > filesystem, a reboot then a fsck the system worked fine. There
> > were no bad reports from the fsck. Yes, I said no bad reports from
> > fsck, it did take 3.5 hours though. What's causing this?
> >
> > Mar 8 01:15:47 files kernel: lvm - lvm_map access beyond end of device;
> > *rsector: 2451636592 or size: 8 wrong for minor: 0
> > Mar 8 01:15:47 files kernel: Bad lvm_map in ll_rw_block
> > Mar 8 01:15:47 files kernel: EXT2-fs error (device lvm(58,0)):
> > ext2_readdir: bad entry in directory #43122713: rec_len is smaller than
> > minimal - offset=0, inode=0, rec_len=0, name_len=0
> > Mar 8 01:15:47 files kernel: Remounting filesystem read-only
> > Mar 8 01:15:48 files kernel: lvm - lvm_map access beyond end of device;
> > *rsector: 2596938272 or size: 8 wrong for minor: 0
> > Mar 8 01:15:48 files kernel: Bad lvm_map in ll_rw_block
> > Mar 8 01:15:48 files kernel: EXT2-fs error (device lvm(58,0)):
> > ext2_readdir: bad entry in directory #43122714: rec_len is smaller than
> > minimal - offset=0, inode=0, rec_len=0, name_len=0
> > Mar 8 01:15:48 files kernel: Remounting filesystem read-only
>
> Is this the only output in your syslog, a representative sample, a
> small part of a huge number of messages? How often do you have this
> problem, or is it the first time?
>
This was a `grep kernel` of the days syslog file. I did take a look and
it was the only thing
relevant.
>
> Can you verify that inodes 43122713 and 43122714 are actually valid
> directories or at least valid inode numbers? dumpe2fs -h should be
> enough to tell you the number of inodes in the filesystem.
>
# dumpe2fs -h /dev/vg0/lv0
Filesystem volume name: <none>
Last mounted on: <not available>
Filesystem UUID: 1e473942-d8f1-4e48-905f-2f872f7e4424
Filesystem magic number: 0xEF53
Filesystem revision #: 1 (dynamic)
Filesystem features: filetype sparse_super
Filesystem state: not clean
Errors behavior: Continue
Filesystem OS type: Linux
Inode count: 87375872
Block count: 174723072
Reserved block count: 0
Free blocks: 163429202
Free inodes: 86687944
First block: 0
Block size: 4096
Fragment size: 4096
Blocks per group: 32768
Fragments per group: 32768
Inodes per group: 16384
Inode blocks per group: 512
Last mount time: Thu Mar 8 12:28:00 2001
Last write time: Thu Mar 8 22:42:13 2001
Mount count: 1
Maximum mount count: 20
Last checked: Thu Mar 8 12:27:58 2001
Check interval: 15552000 (6 months)
Next check after: Tue Sep 4 13:27:58 2001
Reserved blocks uid: 0 (user root)
Reserved blocks gid: 0 (group root)
First inode: 11
Inode size: 128
>
> According to my calculations for your 656 GB 4kB block filesystem:
>
> sector 2451636592 / 8 sectors/block = 306454574
> sector 2596938272 / 8 sectors/block = 324617284
>
> 656 GB * 1024 MB/GB * 256 blocks/MB = 171966464 blocks
>
> So LVM is correct in refusing to map these blocks. The real question is
> where do the block numbers come from? The "bad entry" messages are
> simply a result of LVM not filling in the buffer for ext2, and it is
> all zeros.
>
> The first point where we could have a bogus block number would be
> in inode_getblk(), where we access inode->u.ext2_i.i_data[0] (the
> block number here is not checked), but you say that e2fsck reported
> all was well.
>
> The below patch for 2.2.18 verifies the block numbers read from disk
> before reading them. It would at least help narrow down the problem here.
I'll see if I can add them in next reboot... which is tricky business
with a 24x7 machine in
production. I'll insert this into 2.2.19 when it comes out.
>
>
> Cheers, Andreas
> ========================================================================
> --- fs/ext2/inode.c.orig Wed Jan 17 03:22:51 2001
> +++ fs/ext2/inode.c Thu Mar 8 17:35:33 2001
> @@ -228,13 +228,20 @@
> int create, int new_block, int * err)
> {
> u32 * p;
> - int tmp, goal = 0;
> + u32 tmp, goal = 0;
> struct buffer_head * result;
> int blocks = inode->i_sb->s_blocksize / 512;
>
> p = inode->u.ext2_i.i_data + nr;
> repeat:
> tmp = *p;
> + if (tmp > le32_to_cpu(EXT2_SB(inode->i_sb)->s_es->s_blocks_count)) {
> + ext2_warning(inode->i_sb, __FUNCTION__,
> + "inode #%u has bad direct block[%d] = %u\n",
> + inode->i_ino, nr, tmp);
> + *err = -EIO;
> + return NULL;
> + }
> if (tmp) {
> struct buffer_head * result;
> result = getblk (inode->i_dev, le32_to_cpu(tmp), inode->i_sb->s_blocksize);
> @@ -293,7 +301,7 @@
> int create, int blocksize,
> int new_block, int * err)
> {
> - int tmp, goal = 0;
> + u32 tmp, goal = 0;
> u32 * p;
> struct buffer_head * result;
> int blocks = inode->i_sb->s_blocksize / 512;
> @@ -311,6 +319,13 @@
> p = (u32 *) bh->b_data + nr;
> repeat:
> tmp = le32_to_cpu(*p);
> + if (tmp > le32_to_cpu(EXT2_SB(inode->i_sb)->s_es->s_blocks_count)) {
> + ext2_warning(inode->i_sb, __FUNCTION__,
> + "inode #%u has bad indirect block[%u][%d] = %u\n",
> + inode->i_ino, bh->b_blocknr, nr, tmp);
> + *err = -EIO;
> + return NULL;
> + }
> if (tmp) {
> result = getblk (bh->b_dev, tmp, blocksize);
> if (tmp == le32_to_cpu(*p)) {
-
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