On Tue, Aug 12, 2008 at 09:25:54AM -0700, Mingming Cao wrote:
> +int ext4_meta_trans_blocks(struct inode* inode, int nrblocks, int idxblocks)
> +{
> + int groups, gdpblocks;
> + int ret = 0;
> +
> + groups = nrblocks + idxblocks;
> + gdpblocks = groups;
> + if (groups > EXT4_SB(inode->i_sb)->s_groups_count)
> + groups = EXT4_SB(inode->i_sb)->s_groups_count;
> + if (groups > EXT4_SB(inode->i_sb)->s_gdb_count)
> + gdpblocks = EXT4_SB(inode->i_sb)->s_gdb_count;
I guess we should pass chunk to ext4_meta_trans_blocks also.
if (chunk) we should update only one group descriptor and one
bitmap block ie,
if(chunk)
groups = 1 + idxblocks;
> +
> + /* bitmaps and block group descriptor blocks */
> + ret += groups + gdpblocks;
> +
> + ret += idxblocks;
> +
> + /* journalled mode, include buffer to modify data blocks */
> + if (ext4_should_journal_data(inode))
> + ret += nrblocks;
> +
> + /* Blocks for super block, inode, quota and xattr blocks */
> + ret += EXT4_META_TRANS_BLOCKS(inode->i_sb);
> +
> + return ret;
> +}
> +
....
...
> +static int ext4_writeblocks_trans_credits_old(struct inode *inode, int nrblocks,
> + int chunk)
> {
> - int bpp = ext4_journal_blocks_per_page(inode);
> - int indirects = (EXT4_NDIR_BLOCKS % bpp) ? 5 : 3;
> + int indirects;
> int ret;
>
> - if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)
> - return ext4_ext_writepage_trans_blocks(inode, bpp);
> -
> - if (ext4_should_journal_data(inode))
> - ret = 3 * (bpp + indirects) + 2;
> - else
> - ret = 2 * (bpp + indirects) + 2;
> + /*
> + * How many index blocks need to touch to modify nrblocks?
> + * The "Chunk" flag indicating whether the nrblocks is
> + * physically contigous on disk
> + *
> + * For Direct IO and fallocate, they calls get_block to allocate
> + * one single extent at a time, so they could set the "Chunk" flag
> + */
> + indirects = ext4_indirect_trans_blocks(inode, nrblocks, chunk);
>
> -#ifdef CONFIG_QUOTA
> - /* We know that structure was already allocated during DQUOT_INIT so
> - * we will be updating only the data blocks + inodes */
> - ret += 2*EXT4_QUOTA_TRANS_BLOCKS(inode->i_sb);
> -#endif
> + /* Account for block group bitmaps and block groups
> + * descriptors.Worse case, the nrblocks+indirects blocks spread
> + * over different block groups
> + */
> + ret = ext4_meta_trans_blocks(inode, nrblocks, indirects);
>
> return ret;
> }
-aneesh
--
To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
