Re: [PATCH] bfs iget() abuses

[Tigran Aivazian]

Hi Al,

Yes, looks good to me and also I confirm that ->i_dsk_ino is only zero for 
deletes inodes.

Kind regards
Tigran

On Tue, 4 Oct 2005, Al Viro wrote:

> 	bfs_fill_super() walks the inode table to get the bitmap of
> free inodes and collect stats.  It has no business using iget() for
> that - it's a lot of extra work, extra icache pollution and more
> complex code.  Switched to walking the damn thing directly.
>
> 	Note: that also allows to kill ->i_dsk_ino in there - separate
> patch if Tigran can confirm that this field can be zero only for deleted
> inodes (i.e. something that could only be found during that scan and not
> by normal lookups).
>
> Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
> ----
> [this is a followup to Alexey's bfs annotations patch]
>
> diff -urN RC14-rc3-git4-base/fs/bfs/inode.c current/fs/bfs/inode.c
> --- RC14-rc3-git4-base/fs/bfs/inode.c	2005-10-04 12:30:06.000000000 -0400
> +++ current/fs/bfs/inode.c	2005-10-04 05:57:46.000000000 -0400
> @@ -362,23 +362,41 @@
> 	info->si_lf_eblk = 0;
> 	info->si_lf_sblk = 0;
> 	info->si_lf_ioff = 0;
> +	bh = NULL;
> 	for (i=BFS_ROOT_INO; i<=info->si_lasti; i++) {
> -		inode = iget(s,i);
> -		if (BFS_I(inode)->i_dsk_ino == 0)
> +		struct bfs_inode *di;
> +		int block = (i - BFS_ROOT_INO)/BFS_INODES_PER_BLOCK + 1;
> +		int off = (i - BFS_ROOT_INO) % BFS_INODES_PER_BLOCK;
> +		unsigned long sblock, eblock;
> +
> +		if (!off) {
> +			brelse(bh);
> +			bh = sb_bread(s, block);
> +		}
> +
> +		if (!bh)
> +			continue;
> +
> +		di = (struct bfs_inode *)bh->b_data + off;
> +
> +		if (!di->i_ino) {
> 			info->si_freei++;
> -		else {
> -			set_bit(i, info->si_imap);
> -			info->si_freeb -= inode->i_blocks;
> -			if (BFS_I(inode)->i_eblock > info->si_lf_eblk) {
> -				info->si_lf_eblk = BFS_I(inode)->i_eblock;
> -				info->si_lf_sblk = BFS_I(inode)->i_sblock;
> -				info->si_lf_ioff = BFS_INO2OFF(i);
> -			}
> +			continue;
> +		}
> +		set_bit(i, info->si_imap);
> +		info->si_freeb -= BFS_FILEBLOCKS(di);
> +
> +		sblock =  le32_to_cpu(di->i_sblock);
> +		eblock =  le32_to_cpu(di->i_eblock);
> +		if (eblock > info->si_lf_eblk) {
> +			info->si_lf_eblk = eblock;
> +			info->si_lf_sblk = sblock;
> +			info->si_lf_ioff = BFS_INO2OFF(i);
> 		}
> -		iput(inode);
> 	}
> +	brelse(bh);
> 	if (!(s->s_flags & MS_RDONLY)) {
> -		mark_buffer_dirty(bh);
> +		mark_buffer_dirty(info->si_sbh);
> 		s->s_dirt = 1;
> 	}
> 	dump_imap("read_super", s);
-
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