Re: [PATCH 001 of 8] knfsd: Add nfs-export support to tmpfs

From: Andrew Morton
Date: Fri Sep 29 2006 - 02:30:34 EST


On Fri, 29 Sep 2006 13:08:39 +1000
NeilBrown <neilb@xxxxxxx> wrote:

> +static int shmem_encode_fh(struct dentry *dentry, __u32 *fh, int *len, int connectable)
> +{
> + struct inode *inode = dentry->d_inode;
> +
> + if (*len < 2)
> + return 255;
> +
> + if (hlist_unhashed(&inode->i_hash)) {
> + /* Unfortunately insert_inode_hash is not idempotent,
> + * so as we hash inodes here rather than at creation
> + * time, we need a lock to ensure we only try
> + * to do it once
> + */
> + static DEFINE_SPINLOCK(lock);
> + spin_lock(&lock);
> + if (hlist_unhashed(&inode->i_hash))
> + insert_inode_hash(inode);
> + spin_unlock(&lock);
> + }

This looks fishy.

How do we get two callers in here at the same time for the same inode?

Why don't other filesystems have the same problem?


-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/