Re: ubifs, race between link and unlink/rename?

[hooanon05@yahoo.co.jp]

Artem Bityutskiy:
> > Consider a scenario when 'vfs_link(dirA/fileA)' and
> > 'vfs_unlink(dirA/fileA, dirB/fileB)' race. 'vfs_link()' does not
> > lock 'dirA->i_mutex', so this is possible. Both of the functions
	:::
> Pushing this patch to ubifs-2.6.git, thanks.

Ah, I am late.
We need one minor correction.


> @@ -528,6 +528,25 @@ static int ubifs_link(struct dentry *old_dentry, struct inode *dir,
>  		inode->i_nlink, dir->i_ino);
>  	ubifs_assert(mutex_is_locked(&dir->i_mutex));
>  	ubifs_assert(mutex_is_locked(&inode->i_mutex));
> +
> +	/*
> +	 * Return -ENOENT if we've raced with unlink and i_nlink is 0.  Doing
> +	 * otherwise has the potential to corrupt the orphan inode list.
> +	 *
> +	 * Indeed, consider a scenario when 'vfs_link(dirA/fileA)' and
> +	 * 'vfs_unlink(dirA/fileA, dirB/fileB)' race. 'vfs_link()' does not

This comment is confusing.
Need to swich vfs_unlink and vfs_link. :-)


J. R. Okajima