From mboxrd@z Thu Jan 1 00:00:00 1970 From: Piergiorgio Sartor Subject: Re: Why does one get mismatches? Date: Tue, 2 Mar 2010 19:49:40 +0100 Message-ID: <20100302184940.GA2243@lazy.lzy> References: <20100211175133.GA30187@atlantis.cc.ndsu.nodak.edu> <4B7B0D45.7040801@tmr.com> <6db64f7872286165ac1fd3436e9d6476@localhost> <20100218100547.7aecdc34@notabene.brown> <4B853BBF.7000607@tmr.com> <20100224185106.GA5426@lazy.lzy> <20100225092106.5b7dd6ba@notabene.brown> <20100225084141.GA2927@lazy.lzy> <20100302155700.68236f28@notabene.brown> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20100302155700.68236f28@notabene.brown> Sender: linux-raid-owner@vger.kernel.org To: Neil Brown Cc: Piergiorgio Sartor , "Martin K. Petersen" , Bill Davidsen , Steven Haigh , Bryan Mesich , Jon@eHardcastle.com, linux-raid@vger.kernel.org List-Id: linux-raid.ids Hi, > Thanks. I finally had a look at these (sorry for delay). well, thank you for having a look at the thing. > If you run "file" on one of the dumps, it tells you: > > $ file disk1.raw > disk1.raw: Minix filesystem > > Which isn't expected. I would expect something like > $ file xxx > xxx: Linux rev 1.0 ext3 filesystem data, UUID=fe55fe6f-0412-4a0a-852d-a0e21767aa35 (needs journal recovery) (large files) > > for an ext3 filesystem. > > Looking at /usr/share/misc/magic, it seems that a Minix filesystem is defined > by: > 0x410 leshort 0x137f Minix filesystem > > i.e. the 2 bytes at 0x410 into the device are 0x137f, which exactly what we > find in your dump. > > 0x410 in an ext3 superblock is the lower bytes of "s_free_inodes_count", the > count of free inodes. > Your actual number is 14881663, which is 0x00E3137F. Ah! But this means there is a bug somewhere... > So if you just add or remove a file, the number of free inodes should change, > and your filesystem will no longer look like a Minix filesystem and > your problems should go away. Uhm, OK, I just re-created the MD and the FS, so I took also the opportunity to increase the chunk size to 512K and use RAID-10. > I guess libblkid et-al should do more sanity checks on the superblock before > deciding that it really belongs to some particular filesystem. So, should one of us file a bug report somewhere? I mean, it is not only (lib)blkid, but also "file" which seems to be confused. BTW, "file" does not seem to use libblkid. > But I'm happy - this clearly isn't a raid problem. That's certainly good news, thanks again for the explanation, I learned something today! bye, -- piergiorgio