From: Theodore Ts'o <tytso@mit.edu>
To: Felipe Monteiro de Carvalho <felipemonteiro.carvalho@gmail.com>
Cc: linux-ext4@vger.kernel.org
Subject: Re: Beginner questions about ext4
Date: Mon, 15 Jul 2013 14:59:53 -0400 [thread overview]
Message-ID: <20130715185953.GE26359@thunk.org> (raw)
In-Reply-To: <CACyNnZN7jGKYp5P87+OYJzAa-iVWMvBSujBh==A=w642RFDUvQ@mail.gmail.com>
On Mon, Jul 15, 2013 at 08:18:16PM +0200, Felipe Monteiro de Carvalho wrote:
> wow, that's a pretty amazing tool, didn't know about it.
Are you familiar with debugfs? I'd also strongly suggest that you try
using that program to try to understand the file system layout.
>But my table of group descriptors read from group nr 0 is all correct
>between group nr 0 and 31, but group nr 32 to 63 are filled with
>zeroes.
> Filesystem features: has_journal ext_attr resize_inode dir_index filetype needs_recovery extent flex_bg sparse_super large_file huge_file uninit_bg dir_nlink extra_isize
The file system does not have the 64-bit feature set. Hence, the
layout of the block grup descriptor is struct ext2_group_desc, and not
struct ext4_group_desc.
I'm guessing that you were using the ext4_group_desc structure (which
is 64 bytes) instead of the ext2_group_desc structure (which is 32
bytes).
I would suggest that you match up the contents of your in-program data
structures, and compare it to the outputs of debugfs and dumpe2fs.
- Ted
next prev parent reply other threads:[~2013-07-15 18:59 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-06-12 12:20 Beginner questions about ext4 Felipe Monteiro de Carvalho
2013-06-23 6:29 ` Felipe Monteiro de Carvalho
2013-06-23 11:59 ` Theodore Ts'o
2013-07-01 15:23 ` Felipe Monteiro de Carvalho
2013-07-01 16:55 ` Theodore Ts'o
2013-07-10 16:13 ` Felipe Monteiro de Carvalho
2013-07-10 17:24 ` Theodore Ts'o
2013-07-11 7:37 ` Felipe Monteiro de Carvalho
2013-07-11 15:23 ` Theodore Ts'o
2013-07-15 10:20 ` Felipe Monteiro de Carvalho
2013-07-15 13:43 ` Theodore Ts'o
2013-07-15 16:09 ` Felipe Monteiro de Carvalho
2013-07-15 16:37 ` Theodore Ts'o
2013-07-15 17:55 ` Felipe Monteiro de Carvalho
2013-07-15 18:10 ` Theodore Ts'o
2013-07-15 18:18 ` Felipe Monteiro de Carvalho
2013-07-15 18:59 ` Theodore Ts'o [this message]
2013-07-16 6:14 ` Felipe Monteiro de Carvalho
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