On Mon, 3 May 2010 18:51:21 -0400, "Theodore Ts'o" <tytso@xxxxxxx> wrote:
> @@ -2560,45 +2522,50 @@ static int ext4_da_get_block_prep(struct inode *inode, sector_t iblock,
> invalid_block = ~0;
>
> BUG_ON(create == 0);
> - BUG_ON(bh_result->b_size != inode->i_sb->s_blocksize);
> + BUG_ON(bh->b_size != inode->i_sb->s_blocksize);
> +
> + map.m_lblk = iblock;
> + map.m_len = 1;
>
> /*
> * first, we need to know whether the block is allocated already
> * preallocated blocks are unmapped but should treated
> * the same as allocated blocks.
> */
> - ret = ext4_get_blocks(NULL, inode, iblock, 1, bh_result, 0);
> - if ((ret == 0) && !buffer_delay(bh_result)) {
> - /* the block isn't (pre)allocated yet, let's reserve space */
> - /*
> - * XXX: __block_prepare_write() unmaps passed block,
> - * is it OK?
> - */
> - ret = ext4_da_reserve_space(inode, iblock);
> - if (ret)
> - /* not enough space to reserve */
> - return ret;
> -
> - map_bh(bh_result, inode->i_sb, invalid_block);
> - set_buffer_new(bh_result);
> - set_buffer_delay(bh_result);
> - } else if (ret > 0) {
> - bh_result->b_size = (ret << inode->i_blkbits);
> - if (buffer_unwritten(bh_result)) {
> - /* A delayed write to unwritten bh should
> - * be marked new and mapped. Mapped ensures
> - * that we don't do get_block multiple times
> - * when we write to the same offset and new
> - * ensures that we do proper zero out for
> - * partial write.
> + ret = ext4_map_blocks(NULL, inode, &map, 0);
> + if (ret < 0)
> + return ret;
> + if (ret == 0) {
> + if (!buffer_delay(bh)) {
bh flags are not set here. This check should be based on map.m_flags.
> + /*
> + * XXX: __block_prepare_write() unmaps passed
> + * block, is it OK?
> */
> - set_buffer_new(bh_result);
> - set_buffer_mapped(bh_result);
> + ret = ext4_da_reserve_space(inode, iblock);
> + if (ret)
> + return ret; /* not enough space to reserve */
> +
> + map_bh(bh, inode->i_sb, invalid_block);
> + set_buffer_new(bh);
> + set_buffer_delay(bh);
> }
> - ret = 0;
> + return 0;
> }
>
Only thing i am worried about is we were modifying bh_flags in all
possible confusing ways. We may want to make sure we get the update
correct. I am still going through the patch after applying it to the
tree. So may take more time to look at the full changeset.
-aneesh
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