Re: [gentoo-user] [OT] Problem with disk: cannot mount as ext3 but can as ext2

[Richard Fish]

On 10/8/06, gregory.sacre@×××××.com <gregory.sacre@×××××.com> wrote:
> |        In some cases useful info is found in syslog - try
> |        dmesg | tail  or so

This was good advice....

> | # fsck.ext3 -p /dev/hdd
> | fsck.ext3: Bad magic number in super-block while trying to open /dev/hdd
> | /dev/hdd:

Should have used /dev/hdd1 here....

> | # e2fsck -b 8193 /dev/hdd
> | e2fsck 1.39 (29-May-2006)
> | e2fsck: Bad magic number in super-block while trying to open /dev/hdd

...and here...

> ext2... and it worked!!! I tried then to mount it normally, not
> anymore as read-only with ext2 format... and it worked!!!
> So my first question is: how come?

Possibly a disk error on the blocks that would normally be reserved
for the ext3 journal...

> | /dev/hdd1: Attempt to read block from filesystem resulted in short
>   read while reading block 525
> |
> | /dev/hdd1: Attempt to read block from filesystem resulted in short
>   read reading journal superblock

...which is sort of what this message says.

> Is there anything wrong with my hardware? Is it a super-block problem?
> Is there a way to solve it?

First, check the dmesg output after running "fsck.ext3 /dev/hdd1".
That may show read errors on the disk, and if so, I'm guessing those
blocks are now bad.  You can also use smartctl (emerge smartmontools)
to query the SMART information from the drive, or to run a SMART
self-test of the disk.

I believe you can also convert the filesystem to ext2, with "tune2fs
-O ^has_journal /dev/hdd1".  This should allow you to run fsck.ext2 on
the filesystem, to check it for other consistency errors.

-Richard
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