Hi Ted,
(2010/03/06 1:10), tytso@xxxxxxx wrote:
> On Fri, Mar 05, 2010 at 05:19:53PM +0900, Akira Fujita wrote:
>>
>> Sounds interesting.
>> It seems to be able to try easily except (2).
>> I think that we can mark block bitmap as in use with debugfs (do_setb).
>> Do you have another better idea for the tool you mentioned at (2)?
>
> The libext2fs library is very powerful. :-)
>
> Here's a quicky program I whipped up fairly quickly. The code that
> actually messes with the block bitmap is in the for loop; the rest is
> just generic setup. Feel free to reuse this program as a framework
> for other times when you want to quickly create a program to do
> something programmatic where debugfs isn't quite powerful enough for
> your needs.
>
> I have considered trying to integrate tcl into debugfs, so that you
> could do this in thing more easily in debugfs directly, but it's so
> easy to write throwaway C programs that I've never bothered.
>
Thank you.
This program will be great help for my work.
I will give it a shot.
Regards,
Akria Fujita.
> /*
> * fill-bitmap.c --- Program which writes marks roughly half of the
> * blocks in the filesystem as being in use.
> *
> * Compile via: cc -o fill-bitmap fill-bitmap.c -lext2fs -lcom_err
> *
> * Copyright 2010 by Theodore Ts'o.
> *
> * %Begin-Header%
> * This file may be redistributed under the terms of the GNU Public
> * License.
> * %End-Header%
> */
>
> #include<ext2fs/ext2_fs.h>
> #include<ext2fs/ext2fs.h>
> #include<et/com_err.h>
> #include<stdlib.h>
>
> char *program_name;
>
> static void usage(void)
> {
> fprintf(stderr, "Usage: %s device\n", program_name);
> exit (1);
> }
>
> int main (int argc, char ** argv)
> {
> errcode_t retval;
> ext2_filsys fs;
> char *device_name;
> blk_t blk;
>
> add_error_table(&et_ext2_error_table);
> if (argc != 2)
> usage();
> program_name = argv[0];
> device_name = argv[1];
>
> retval = ext2fs_open (device_name, EXT2_FLAG_RW, 0, 0,
> unix_io_manager,&fs);
> if (retval) {
> com_err(program_name, retval, "while trying to open %s",
> device_name);
> exit(1);
> }
>
> retval = ext2fs_read_bitmaps(fs);
> if (retval) {
> com_err(program_name, retval, "while reading bitmaps");
> exit(1);
> }
>
> for (blk = fs->super->s_first_data_block;
> blk< fs->super->s_blocks_count; blk++) {
> if (ext2fs_test_block_bitmap(fs->block_map, blk))
> continue;
>
> if (random()& 1)
> continue;
>
> ext2fs_mark_block_bitmap(fs->block_map, blk);
> ext2fs_block_alloc_stats(fs, blk, 1);
> }
>
> ext2fs_close(fs);
> remove_error_table(&et_ext2_error_table);
> exit (0);
> }
>
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