From: J. Bruce Fields <bfields@redhat.com>
Date: Wed, 12 Mar 2014 16:19:23 +0000 (-0400)
Subject: dcache: d_splice_alias should detect loops
X-Git-Tag: v3.17-rc1~44^2~4
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=95ad5c291313b66a98a44dc92b57e0b37c1dd589;p=platform%2Fkernel%2Flinux-exynos.git

dcache: d_splice_alias should detect loops

I believe this can only happen in the case of a corrupted filesystem.
So -EIO looks like the appropriate error.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---

diff --git a/fs/dcache.c b/fs/dcache.c
index 85a2aad..ad13700 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -2706,6 +2706,11 @@ struct dentry *d_splice_alias(struct inode *inode, struct dentry *dentry)
 				dput(new);
 				return ERR_PTR(-EIO);
 			}
+			if (d_ancestor(new, dentry)) {
+				spin_unlock(&inode->i_lock);
+				dput(new);
+				return ERR_PTR(-EIO);
+			}
 			write_seqlock(&rename_lock);
 			__d_materialise_dentry(dentry, new);
 			write_sequnlock(&rename_lock);