On Saturday 24 May 2008, Mark Fasheh wrote:
> From: Josef Bacik <jbacik@xxxxxxxxxx>
>
> Here is my updated generic block based fiemap implementation with the fixes
> that Andreas suggested. Basically any block based fs (this patch includes
> ext3) just has to declare its own fiemap() function and then call this
> generic function with its own get_block_t.
>
> +int generic_block_fiemap(struct inode *inode,
> + struct fiemap_extent_info *fieinfo, u64 start,
> + u64 len, get_block_t *get_block)
> +{
> + struct buffer_head tmp;
[ ... ]
> + do {
> + /*
> + * we set b_size to the total size we want so it will map as
> + * many contiguous blocks as possible at once
> + */
> + memset(&tmp, 0, sizeof(struct buffer_head));
> + tmp.b_size = map_len;
> +
> + ret = get_block(inode, start_blk, &tmp, 0);
> + if (ret)
> + break;
> +
> + /* HOLE */
> + if (!tmp.b_blocknr) {
This should be if (!buffer_mapped(&tmp)).
You can't be sure that filesystems returning a hole will use a b_blocknr of
zero, and you can't be sure that a block number of zero is a hole.
-chris
-chris
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