Commit a3f432bf authored Oct 15, 2013 by J. Bruce Fields Committed by Trond Myklebust Oct 28, 2013

nfs: use IS_ROOT not DCACHE_DISCONNECTED



This check was added by Al Viro with
d9e80b7d "nfs d_revalidate() is too
trigger-happy with d_drop()", with the explanation that we don't want to
remove the root of a disconnected tree, which will still be included on
the s_anon list.

But DCACHE_DISCONNECTED does *not* actually identify dentries that are
disconnected from the dentry tree or hashed on s_anon.  IS_ROOT() is the
way to do that.

Also add a comment from Al's commit to remind us why this check is
there.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

parent 9d3a2260

fs/nfs/dir.c

+7 −1

Original line number	Diff line number	Diff line
		@@ -1139,7 +1139,13 @@ out_zap_parent:
		if (inode && S_ISDIR(inode->i_mode)) {
		/* Purge readdir caches. */
		nfs_zap_caches(inode);
		if (dentry->d_flags & DCACHE_DISCONNECTED)
		/*
		* We can't d_drop the root of a disconnected tree:
		* its d_hash is on the s_anon list and d_drop() would hide
		* it from shrink_dcache_for_unmount(), leading to busy
		* inodes on unmount and further oopses.
		*/
		if (IS_ROOT(dentry))
		goto out_valid;
		}
		/* If we have submounts, don't unhash ! */

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