Re: BUG: warning at fs/ext3/inode.c:1016/ext3_getblk()

Dave Kleikamp
2006-09-05T21:19:42Z

On Tue, 2006-09-05 at 13:14 -0700, Badari Pulavarty wrote:
> Dave Kleikamp wrote:

> > I'm having a hard time figuring out exactly what ext3_get_blocks_handle
> > is trying to return, but it looks to me like if it is allocating one
> > data block, and needs to allocate an indirect block as well, then it
> > will return 2 rather than 1. Is this expected, or am I just confused?
> >
> >
>
> It would return "1" in that case.. (data block)
>
> > 0 means get_block() suceeded and indicates the number of blocks mapped
> = 0 lookup failed
> < 0 mean error case

Okay, I got confused looking through the code. I still don't see how
ext3_get_blocks_handle() should be returning a number greater than
maxblocks.

> >> I did search for callers of ext3_get_blocks_handle() and found that
> >> ext3_readdir() seems to do wrong thing all the time with error check :(
> >> Need to take a closer look..
> >>
> >> err = ext3_get_blocks_handle(NULL, inode, blk, 1,
> >> &map_bh, 0, 0);
> >> if (err > 0) { <<<< BAD
> >> page_cache_readahead(sb->s_bdev->bd_inode->i_mapping,
> >> &filp->f_ra,
> >> filp,
> >> map_bh.b_blocknr >>
> >> (PAGE_CACHE_SHIFT - inode->i_blkbits),
> >> 1);
> >> bh = ext3_bread(NULL, inode, blk, 0, &err);
> >> }
> >>
> >
> > Bad to do what it's doing, or bad to call name the variable "err"?
> > I think if it looked like this:
> >
> > count = ext3_get_blocks_handle(NULL, inode, blk, 1,
> > &map_bh, 0, 0);
> > if (count > 0) {
> >
> > it would be a lot less confusing.
> >
> I am sorry !! it is doing the right thing :(

Not your fault. The variable is very badly named.
--
David Kleikamp
IBM Linux Technology Center