Re: [PATCH 08/19] pramfs: file operations for dirs

[Al Viro <viro@ZenIV.linux.org.uk>]

On Sat, Sep 07, 2013 at 10:22:36AM +0200, Marco Stornelli wrote:
> +int pram_add_link(struct dentry *dentry, struct inode *inode)
> +{
> +	struct inode *dir = dentry->d_parent->d_inode;
> +	struct pram_inode *pidir, *pi, *pitail = NULL;
> +	u64 tail_ino, prev_ino;
> +
> +	const char *name = dentry->d_name.name;
> +
> +	int namelen = min_t(unsigned int, dentry->d_name.len, PRAM_NAME_LEN);

Whatever the hell for?  Your ->lookup() rejects dentries with names longer
than PRAM_NAME_LEN with an error, so they won't reach this function at all.

> +int pram_remove_link(struct inode *inode)

Umm...  That's called on rename (for old one) *and* inode eviction when link
count goes to zero.  What's the point of keeping unlinked ones (unlink/rmdir/
rename victims) on those lists?  Sure, you skip them on lookups, but why
delay link removal until eviction?  You pay for that with extra locking,
BTW - if not for that, you wouldn't need your i_link_mutex at all.

> +	pi = pram_get_inode(sb, inode->i_ino);
> +
> +	switch ((u32)file->f_pos) {
> +	case 0:
> +		ret = dir_emit_dot(file, ctx);
> +		ctx->pos = 1;
> +		return ret;

Really?  So on the first call of ->iterate() you just generate one
entry and don't even try to produce more?  And it looks like the
rest is no nicer...