On Mon, Jan 25, 2021 at 04:45:07PM +0100, Jan Kara wrote: > > What do you mean by "take"? Take the superblock as an argument to > > quotactl_sb() or take a reference to the superblock? > > Sorry, I don't really get where you aiming at. > > I think Christoph was pointing at the fact it is suboptimal to search for > superblock by device number when you already have a pointer to it. And I > guess he was suggesting we could pass 'sb' pointer to quotactl_sb() when we > already have it. Although to be honest, I'm not sure how Christoph imagines > the refactoring of user_get_super() he mentions - when we have a path > looked up through user_path(), that pins the superblock the path is on so > it cannot be unmounted. So perhaps quotactl_sb() can done like: I don't think we need a quotactl_sb at all, do_quotactl is in fact a pretty good abstraction as-is. For the path based one we just need to factor out a little helper to set excl and thaw and then call it like: sb = path.dentry->d_inode->i_sb; if (excl) down_write(&sb->s_umount); else down_read(&sb->s_umount); if (thawed && sb->s_writers.frozen != SB_UNFROZEN) ret = -EBUSY; else ret = do_quotactl(sb, type, cmds, id, addr, &path); if (excl) up_write(&sb->s_umount); else up_read(&sb->s_umount); as there is no good reason to bring over the somewhat strange wait until unfrozen semantics to a new syscall.
