Re: [patch 14/23] inodes: Support generic defragmentation

Jörn Engel
2007-11-07T10:22:44Z

On Tue, 6 November 2007 17:11:44 -0800, Christoph Lameter wrote:
>
> +void *get_inodes(struct kmem_cache *s, int nr, void **v)
> +{
> + int i;
> +
> + spin_lock(&inode_lock);
> + for (i = 0; i < nr; i++) {
> + struct inode *inode = v[i];
> +
> + if (inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE))
> + v[i] = NULL;
> + else
> + __iget(inode);
> + }
> + spin_unlock(&inode_lock);
> + return NULL;
> +}
> +EXPORT_SYMBOL(get_inodes);

What purpose does the return type have?

> +/*
> + * Function for filesystems that embedd struct inode into their own
> + * structures. The offset is the offset of the struct inode in the fs inode.
> + */
> +void *fs_get_inodes(struct kmem_cache *s, int nr, void **v,
> + unsigned long offset)
> +{
> + int i;
> +
> + for (i = 0; i < nr; i++)
> + v[i] += offset;
> +
> + return get_inodes(s, nr, v);
> +}
> +EXPORT_SYMBOL(fs_get_inodes);

The fact that all pointers get changed makes me a bit uneasy:
struct foo_inode v[20];
...
fs_get_inodes(..., v, ...);
...
v[0].foo_field = bar;

No warning, but spectacular fireworks.

> +void kick_inodes(struct kmem_cache *s, int nr, void **v, void *private)
> +{
> + struct inode *inode;
> + int i;
> + int abort = 0;
> + LIST_HEAD(freeable);
> + struct super_block *sb;
> +
> + for (i = 0; i < nr; i++) {
> + inode = v[i];
> + if (!inode)
> + continue;

NULL is legal here? Then fs_get_inodes should check for NULL as well
and not add the offset to NULL pointers, I guess.

> + if (inode_has_buffers(inode) || inode->i_data.nrpages) {
> + if (remove_inode_buffers(inode))
> + invalidate_mapping_pages(&inode->i_data,
> + 0, -1);

This linebreak can be removed.

> + }
> +
> + /* Invalidate children and dentry */
> + if (S_ISDIR(inode->i_mode)) {
> + struct dentry *d = d_find_alias(inode);
> +
> + if (d) {
> + d_invalidate(d);
> + dput(d);
> + }
> + }
> +
> + if (inode->i_state & I_DIRTY)
> + write_inode_now(inode, 1);

Once more the three-bit I_DIRTY is used like a boolean value. I don't
hold it against you, specifically. A general review/cleanup is
necessary for that.

Jörn

--
"[One] doesn't need to know [...] how to cause a headache in order
to take an aspirin."
-- Scott Culp, Manager of the Microsoft Security Response Center, 2001