linux-kernel - [PATCH 50/73] union-mount: Create whiteout on unlink() [ver #2]

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Message-ID: <20120221180344.25235.79487.stgit@warthog.procyon.org.uk>
Date:	Tue, 21 Feb 2012 18:03:44 +0000
From:	David Howells <dhowells@...hat.com>
To:	linux-fsdevel@...r.kernel.org, viro@...IV.linux.org.uk,
	valerie.aurora@...il.com
Cc:	linux-kernel@...r.kernel.org, David Howells <dhowells@...hat.com>
Subject: [PATCH 50/73] union-mount: Create whiteout on unlink() [ver #2]

From: Valerie Aurora <vaurora@...hat.com>

Whiteout an unlinked directory entry in a union mounted file system.

Original-author: Valerie Aurora <vaurora@...hat.com>
Signed-off-by: David Howells <dhowells@...hat.com>
---

 fs/namei.c |    9 ++++-----
 1 files changed, 4 insertions(+), 5 deletions(-)

diff --git a/fs/namei.c b/fs/namei.c
index 586913f..ce941ac 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -3333,11 +3333,6 @@ static long do_unlinkat(int dfd, const char __user *pathname)
 	if (nd.last_type != LAST_NORM)
 		goto exit1;
 
-	/* unlink() on union mounts not implemented yet */
-	error = -EINVAL;
-	if (IS_DIR_UNIONED(nd.path.dentry))
-		goto exit1;
-
 	nd.flags &= ~LOOKUP_PARENT;
 
 	mutex_lock_nested(&nd.path.dentry->d_inode->i_mutex, I_MUTEX_PARENT);
@@ -3356,6 +3351,10 @@ static long do_unlinkat(int dfd, const char __user *pathname)
 		error = security_path_unlink(&nd.path, path.dentry);
 		if (error)
 			goto exit3;
+		if (IS_DIR_UNIONED(nd.path.dentry)) {
+			error = do_whiteout(&nd, &path, 0);
+			goto exit3;
+		}
 		error = vfs_unlink(nd.path.dentry->d_inode, path.dentry);
 exit3:
 		mnt_drop_write(nd.path.mnt);

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