From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Thu, 8 Jul 1999 18:56:54 -0400 Message-Id: <199907082256.SAA13689@tsx-prime.MIT.EDU> From: "Theodore Y. Ts'o" In-reply-to: <004a01bec785$01f0f920$0102010a@adminstation.sgymsdam.nl> (buytenh@dsv.nl) Subject: Re: [linux-lvm] Re: ext2resize References: <004a01bec785$01f0f920$0102010a@adminstation.sgymsdam.nl> Sender: owner-linux-lvm Errors-To: owner-linux-lvm List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: buytenh@dsv.nl Cc: linux-lvm@msede.com, linux-fsdevel@vger.rutgers.edu From: "Lennert Buytenhek" Date: Tue, 6 Jul 1999 09:56:07 +0200 I just got an email from John Finlay saying he's got a 52GB fs with 6000+ block groups. So the 1024 block group limit is just bogus. The header in question which #defined the max # of block groups to be 1024 is wrong, then. I'm curious *where* people thought a header defined the max # of block groups to be 1024? Yes, that limit is completely bogus. From: "Lennert Buytenhek" Date: Tue, 6 Jul 1999 10:56:06 +0200 Moving the inode/block bitmap blocks is not that difficult when unmounted, but moving the inode table is tricky to get right (w.r.t atomicity). One ext2resize user got a segfault while the inode table was being moved (yes, that bug is fixed now) a while ago and we're still cleaning up the mess. The trick here is to try *very* hard not to have to do an overlapping move of the inode table (which you may be forced to do if the filesystem is too full, but in most cases it can be avoided). Then do a copy of that portion of the inode table, and only update the GDT *after* the inode table has been safely moved. You may have to move some extra data blocks belonging to files to do this, though, so it's much easier to do this safely during an offline resize. - Ted