ovl: deduplicate lowerpath and lowerstack[]

The ovl_inode contains a copy of lowerpath in lowerstack[0], so the
lowerpath member can be removed.

Use accessor ovl_lowerpath() to get the lowerpath whereever the member
was accessed directly.
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

fs/overlayfs/export.c

@@ -289,9 +289,7 @@ static struct dentry *ovl_obtain_alias(struct super_block *sb,
 	struct inode *inode = NULL;
 	struct ovl_entry *oe;
 	struct ovl_inode_params oip = {
-		.lowerpath = lowerpath,
 		.index = index,
-		.numlower = !!lower
 	};
 
 	/* We get overlay directory dentries with ovl_lookup_real() */

fs/overlayfs/inode.c

@@ -1005,10 +1005,6 @@ void ovl_inode_init(struct inode *inode, struct ovl_inode_params *oip,
 	oi->__upperdentry = oip->upperdentry;
 	oi->oe = oip->oe;
 	oi->redirect = oip->redirect;
-	if (oip->lowerpath && oip->lowerpath->dentry) {
-		oi->lowerpath.dentry = dget(oip->lowerpath->dentry);
-		oi->lowerpath.layer = oip->lowerpath->layer;
-	}
 	if (oip->lowerdata)
 		oi->lowerdata = igrab(d_inode(oip->lowerdata));
 
@@ -1325,7 +1321,7 @@ struct inode *ovl_get_inode(struct super_block *sb,
 {
 	struct ovl_fs *ofs = OVL_FS(sb);
 	struct dentry *upperdentry = oip->upperdentry;
-	struct ovl_path *lowerpath = oip->lowerpath;
+	struct ovl_path *lowerpath = ovl_lowerpath(oip->oe);
 	struct inode *realinode = upperdentry ? d_inode(upperdentry) : NULL;
 	struct inode *inode;
 	struct dentry *lowerdentry = lowerpath ? lowerpath->dentry : NULL;
@@ -1404,7 +1400,7 @@ struct inode *ovl_get_inode(struct super_block *sb,
 
 	/* Check for non-merge dir that may have whiteouts */
 	if (is_dir) {
-		if (((upperdentry && lowerdentry) || oip->numlower > 1) ||
+		if (((upperdentry && lowerdentry) || ovl_numlower(oip->oe) > 1) ||
 		    ovl_path_check_origin_xattr(ofs, &realpath)) {
 			ovl_set_flag(OVL_WHITEOUTS, inode);
 		}

fs/overlayfs/namei.c

@@ -1107,10 +1107,8 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
 	if (upperdentry || ctr) {
 		struct ovl_inode_params oip = {
 			.upperdentry = upperdentry,
-			.lowerpath = stack,
 			.oe = oe,
 			.index = index,
-			.numlower = ctr,
 			.redirect = upperredirect,
 			.lowerdata = (ctr > 1 && !d.is_dir) ?
 				      stack[ctr - 1].dentry : NULL,

fs/overlayfs/overlayfs.h

@@ -653,10 +653,8 @@ bool ovl_is_private_xattr(struct super_block *sb, const char *name);
 struct ovl_inode_params {
 	struct inode *newinode;
 	struct dentry *upperdentry;
-	struct ovl_path *lowerpath;
 	struct ovl_entry *oe;
 	bool index;
-	unsigned int numlower;
 	char *redirect;
 	struct dentry *lowerdata;
 };

fs/overlayfs/ovl_entry.h

@@ -120,6 +120,11 @@ static inline struct ovl_path *ovl_lowerstack(struct ovl_entry *oe)
 	return ovl_numlower(oe) ? oe->__lowerstack : NULL;
 }
 
+static inline struct ovl_path *ovl_lowerpath(struct ovl_entry *oe)
+{
+	return ovl_lowerstack(oe);
+}
+
 /* private information held for every overlayfs dentry */
 static inline unsigned long *OVL_E_FLAGS(struct dentry *dentry)
 {
@@ -136,7 +141,6 @@ struct ovl_inode {
 	unsigned long flags;
 	struct inode vfs_inode;
 	struct dentry *__upperdentry;
-	struct ovl_path lowerpath;
 	struct ovl_entry *oe;
 
 	/* synchronize copy up and more */

fs/overlayfs/super.c

@@ -172,8 +172,6 @@ static struct inode *ovl_alloc_inode(struct super_block *sb)
 	oi->flags = 0;
 	oi->__upperdentry = NULL;
 	oi->oe = NULL;
-	oi->lowerpath.dentry = NULL;
-	oi->lowerpath.layer = NULL;
 	oi->lowerdata = NULL;
 	mutex_init(&oi->lock);
 
@@ -194,7 +192,6 @@ static void ovl_destroy_inode(struct inode *inode)
 	struct ovl_inode *oi = OVL_I(inode);
 
 	dput(oi->__upperdentry);
-	dput(oi->lowerpath.dentry);
 	ovl_free_entry(oi->oe);
 	if (S_ISDIR(inode->i_mode))
 		ovl_dir_cache_free(inode);
@@ -1839,7 +1836,6 @@ static struct dentry *ovl_get_root(struct super_block *sb,
 	int fsid = lowerpath->layer->fsid;
 	struct ovl_inode_params oip = {
 		.upperdentry = upperdentry,
-		.lowerpath = lowerpath,
 		.oe = oe,
 	};
 

fs/overlayfs/util.c

@@ -306,10 +306,12 @@ struct dentry *ovl_i_dentry_upper(struct inode *inode)
 
 struct inode *ovl_i_path_real(struct inode *inode, struct path *path)
 {
+	struct ovl_path *lowerpath = ovl_lowerpath(OVL_I_E(inode));
+
 	path->dentry = ovl_i_dentry_upper(inode);
 	if (!path->dentry) {
-		path->dentry = OVL_I(inode)->lowerpath.dentry;
-		path->mnt = OVL_I(inode)->lowerpath.layer->mnt;
+		path->dentry = lowerpath->dentry;
+		path->mnt = lowerpath->layer->mnt;
 	} else {
 		path->mnt = ovl_upper_mnt(OVL_FS(inode->i_sb));
 	}
@@ -326,9 +328,9 @@ struct inode *ovl_inode_upper(struct inode *inode)
 
 struct inode *ovl_inode_lower(struct inode *inode)
 {
-	struct dentry *lowerdentry = OVL_I(inode)->lowerpath.dentry;
+	struct ovl_path *lowerpath = ovl_lowerpath(OVL_I_E(inode));
 
-	return lowerdentry ? d_inode(lowerdentry) : NULL;
+	return lowerpath ? d_inode(lowerpath->dentry) : NULL;
 }
 
 struct inode *ovl_inode_real(struct inode *inode)