Hi Donato,
On Wed, Jul 8, 2009 at 1:14 PM, Donato Capitella<d.capitella@xxxxxx> wrote:
> Hi there,
> I wrote a dummy function to write to the reserved inode. This is as far
> as I got and I have a few questions:
>
> /**************************************************************/
> void dummy_write_to_inode(struct inode *ino)
> {
> struct buffer_head *bh;
> handle_t *handle;
> int err, blk;
> char dummy_text[] = "The crazy fox jumps over the lazy dog!";
>
> handle = ext3_start_journal(inode, 2);
> if (IS_ERR(handle))
> goto err;
>
> /* allocate a block */
> blk = ext3_new_block(handle, inode, 1, &err);
> if (err)
> goto err;
>
> EXT3_I(inode)->i_data[0] = blk
>
> /* write something to the block */
> bh = sb_bread(ino->sb, blk);
> if (IS_ERR(bh))
> goto err;
>
> memcpy(bh->b_data, dummy_text, sizeof(dummy_text));
> mark_buffer_dirty(bh);
> brelse(bh);
>
> i_size_write(inode, sizeof(dummy_text));
> mark_inode_dirty(inode);
>
ext3_sync_inode(handle, ino);
> ext3_journal_stop(handle);
>
>
> err:
> /* ... error handling code ... */
> }
> /**************************************************************/
>
> For some reason, this code doesn't work as I expected. The block is
> actually written and at the end contains "The lazy fox jumps over the
> lazy dog". The problem is with the inode: it just gets partially
> updated. The block pointer to the first block is updated but the size
> stays zero. How is it possibile that half of the inode gets updated and
> the other half doesn't? What am I missing here?
>
try syncing the inode. This should probably help.
> Thanks,
> Donato
>
> p.s.: I'd also like to know if there is a "smarter" way to write to an
> inode that automatically allocates blocks when needed and the like...
>
>
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>
--
Regards,
Sandeep.
“To learn is to change. Education is a process that changes the learner.”
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