linux-ext4 - Re: ext2fs_test_block_bitmap (): Unknown code ext2 47 #0, etc.

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Message-ID: <20110822043103.GB3671@thunk.org>
Date:	Mon, 22 Aug 2011 00:31:03 -0400
From:	Ted Ts'o <tytso@....edu>
To:	Ivan Shmakov <oneingray@...il.com>
Cc:	linux-ext4@...r.kernel.org
Subject: Re: ext2fs_test_block_bitmap (): Unknown code ext2 47 #0, etc.

On Thu, Aug 18, 2011 at 11:27:30PM +0700, Ivan Shmakov wrote:
> >>>>> Ivan Shmakov <ivan@...y.siamics.net> writes:
> 
> […]
> 
>  > (The support for the whole-image and metadata message digests is not
>  > yet committed.)
> 
> 	The code is now ready to be committed.  However, I'm getting the
> 	following message on stderr upon a call (only the first one?) to
> 	ext2fs_test_block_bitmap ():
> 
> --cut--
> Unknown code ext2 47 #0 for block bitmap for /dev/stdin
> --cut--

You're not getting a human-readable error message because you need to
add the following at the beginning of your program:

	add_error_table(&et_ext2_error_table);

(The error messages are printed by the libcom_err library, and are
defined in lib/ext2fs/ext2_err.et.in, processed to
lib/ext2fs/ext2_err.et, and then compiled to ext2_err.c and ext2_err.h
by the compile_et script in lib/et of e2fsprogs.)

The 47th error message in the ext2 error table, which would have been
printed if you had called add_error_table(), is:

	Illegal block number passed to ext2fs_test_block_bitmap

This means you've passed in a block number which is out-of-range for
the block bitmap.

> 	Also, do I understand it correctly that I need to call
> 	ext2fs_read_block_bitmap () before accessing the block_map
> 	member of the ext2_filsys structure?

Yes, or if you are going to need to read in both the block and inode
bitmaps, you can use ext2fs_read_bitmaps(), which will be more optimal
for reading in the block bitmaps.

							- Ted
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