Iterate over sb->s_inodes instead of sb->s_files in add_dquot_ref. This reduces list search and lock hold time aswell as getting rid of one of the few uses of file_list_lock which Ingo identified as a scalability problem. Previously we called dq_op->initialize for every inode handing of a writeable file that wasn't initialized before. Now we're calling it for every inode that has a non-zero i_writecount, aka a writeable file descriptor refering to it. Thanks a lot to Jan Kara for running this patch through his quota test harness. Note: this is ontop of '[PATCH] move remove_dquot_ref to dqout.c' which I sent out yesterday. Signed-off-by: Christoph Hellwig <hch@xxxxxx> Index: linux-2.6/fs/dquot.c =================================================================== --- linux-2.6.orig/fs/dquot.c 2007-02-05 18:54:36.000000000 +0100 +++ linux-2.6/fs/dquot.c 2007-02-05 18:59:48.000000000 +0100 @@ -689,23 +689,27 @@ /* This routine is guarded by dqonoff_mutex mutex */ static void add_dquot_ref(struct super_block *sb, int type) { - struct list_head *p; + struct inode *inode; restart: - file_list_lock(); - list_for_each(p, &sb->s_files) { - struct file *filp = list_entry(p, struct file, f_u.fu_list); - struct inode *inode = filp->f_path.dentry->d_inode; - if (filp->f_mode & FMODE_WRITE && dqinit_needed(inode, type)) { - struct dentry *dentry = dget(filp->f_path.dentry); - file_list_unlock(); - sb->dq_op->initialize(inode, type); - dput(dentry); - /* As we may have blocked we had better restart... */ - goto restart; - } + spin_lock(&inode_lock); + list_for_each_entry(inode, &sb->s_inodes, i_sb_list) { + if (!atomic_read(&inode->i_writecount)) + continue; + if (!dqinit_needed(inode, type)) + continue; + if (inode->i_state & (I_FREEING|I_WILL_FREE)) + continue; + + __iget(inode); + spin_unlock(&inode_lock); + + sb->dq_op->initialize(inode, type); + iput(inode); + /* As we may have blocked we had better restart... */ + goto restart; } - file_list_unlock(); + spin_unlock(&inode_lock); } /* Return 0 if dqput() won't block (note that 1 doesn't necessarily mean blocking) */ - To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html