From: Miklos Szeredi <mszeredi@redhat.com>
Date: Tue, 17 Mar 2020 14:04:22 +0000 (+0100)
Subject: ovl: separate detection of remote upper layer from stacked overlay
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=7925dad839e70ab43140e26d6b93e807b5969f05;p=linux.git

ovl: separate detection of remote upper layer from stacked overlay

Following patch will allow remote as upper layer, but not overlay stacked
on upper layer.  Separate the two concepts.

This patch is doesn't change behavior.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
---

diff --git a/fs/overlayfs/namei.c b/fs/overlayfs/namei.c
index ed9e129fae04e..a5b998a93a247 100644
--- a/fs/overlayfs/namei.c
+++ b/fs/overlayfs/namei.c
@@ -845,7 +845,8 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
 		if (err)
 			goto out;
 
-		if (upperdentry && unlikely(ovl_dentry_remote(upperdentry))) {
+		if (upperdentry && (upperdentry->d_flags & DCACHE_OP_REAL ||
+				    unlikely(ovl_dentry_remote(upperdentry)))) {
 			dput(upperdentry);
 			err = -EREMOTE;
 			goto out;
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index a05bf1179ce04..bc35cd6233ee6 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -752,13 +752,13 @@ static int ovl_mount_dir(const char *name, struct path *path)
 		ovl_unescape(tmp);
 		err = ovl_mount_dir_noesc(tmp, path);
 
-		if (!err)
-			if (ovl_dentry_remote(path->dentry)) {
-				pr_err("filesystem on '%s' not supported as upperdir\n",
-				       tmp);
-				path_put_init(path);
-				err = -EINVAL;
-			}
+		if (!err && (ovl_dentry_remote(path->dentry) ||
+			     path->dentry->d_flags & DCACHE_OP_REAL)) {
+			pr_err("filesystem on '%s' not supported as upperdir\n",
+			       tmp);
+			path_put_init(path);
+			err = -EINVAL;
+		}
 		kfree(tmp);
 	}
 	return err;
diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c
index f318e4811e32c..997c31509c919 100644
--- a/fs/overlayfs/util.c
+++ b/fs/overlayfs/util.c
@@ -93,8 +93,7 @@ struct ovl_entry *ovl_alloc_entry(unsigned int numlower)
 bool ovl_dentry_remote(struct dentry *dentry)
 {
 	return dentry->d_flags &
-		(DCACHE_OP_REVALIDATE | DCACHE_OP_WEAK_REVALIDATE |
-		 DCACHE_OP_REAL);
+		(DCACHE_OP_REVALIDATE | DCACHE_OP_WEAK_REVALIDATE);
 }
 
 bool ovl_dentry_weird(struct dentry *dentry)