ovl: deduplicate lowerdata and lowerstack[]

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

Use accessors ovl_lowerdata*() to get the lowerdata whereever the member
was accessed directly.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

6 files changed, 22 insertions, 17 deletions

diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
index 4dbf8d880c0f..5239a5bfc6d1 100644
--- a/fs/overlayfs/inode.c
+++ b/fs/overlayfs/inode.c
@@ -1005,8 +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->lowerdata)
-		oi->lowerdata = igrab(d_inode(oip->lowerdata));
 
 	realinode = ovl_inode_real(inode);
 	ovl_copyattr(inode);
diff --git a/fs/overlayfs/namei.c b/fs/overlayfs/namei.c
index 317ab1efc236..8ea2a8358a92 100644
--- a/fs/overlayfs/namei.c
+++ b/fs/overlayfs/namei.c
@@ -1110,8 +1110,6 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
 			.oe = oe,
 			.index = index,
 			.redirect = upperredirect,
-			.lowerdata = (ctr > 1 && !d.is_dir) ?
-				      stack[ctr - 1].dentry : NULL,
 		};
 
 		inode = ovl_get_inode(dentry->d_sb, &oip);
diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
index 8b38844ae341..2ccd6326c2c7 100644
--- a/fs/overlayfs/overlayfs.h
+++ b/fs/overlayfs/overlayfs.h
@@ -656,7 +656,6 @@ struct ovl_inode_params {
 	struct ovl_entry *oe;
 	bool index;
 	char *redirect;
-	struct dentry *lowerdata;
 };
 void ovl_inode_init(struct inode *inode, struct ovl_inode_params *oip,
 		    unsigned long ino, int fsid);
diff --git a/fs/overlayfs/ovl_entry.h b/fs/overlayfs/ovl_entry.h
index 0bb8ab3aa8a7..548c93e030fc 100644
--- a/fs/overlayfs/ovl_entry.h
+++ b/fs/overlayfs/ovl_entry.h
@@ -125,6 +125,20 @@ static inline struct ovl_path *ovl_lowerpath(struct ovl_entry *oe)
 	return ovl_lowerstack(oe);
 }
 
+static inline struct ovl_path *ovl_lowerdata(struct ovl_entry *oe)
+{
+	struct ovl_path *lowerstack = ovl_lowerstack(oe);
+
+	return lowerstack ? &lowerstack[oe->__numlower - 1] : NULL;
+}
+
+static inline struct dentry *ovl_lowerdata_dentry(struct ovl_entry *oe)
+{
+	struct ovl_path *lowerdata = ovl_lowerdata(oe);
+
+	return lowerdata ? lowerdata->dentry : NULL;
+}
+
 /* private information held for every overlayfs dentry */
 static inline unsigned long *OVL_E_FLAGS(struct dentry *dentry)
 {
@@ -134,7 +148,7 @@ static inline unsigned long *OVL_E_FLAGS(struct dentry *dentry)
 struct ovl_inode {
 	union {
 		struct ovl_dir_cache *cache;	/* directory */
-		struct inode *lowerdata;	/* regular file */
+		/* place holder for non-dir */	/* regular file */
 	};
 	const char *redirect;
 	u64 version;
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index 1efc4f252561..dace72ed36c2 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -172,7 +172,6 @@ static struct inode *ovl_alloc_inode(struct super_block *sb)
 	oi->flags = 0;
 	oi->__upperdentry = NULL;
 	oi->oe = NULL;
-	oi->lowerdata = NULL;
 	mutex_init(&oi->lock);
 
 	return &oi->vfs_inode;
@@ -195,8 +194,6 @@ static void ovl_destroy_inode(struct inode *inode)
 	ovl_free_entry(oi->oe);
 	if (S_ISDIR(inode->i_mode))
 		ovl_dir_cache_free(inode);
-	else
-		iput(oi->lowerdata);
 }
 
 static void ovl_free_fs(struct ovl_fs *ofs)
diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c
index 143e6898f50d..b6e66bf8135f 100644
--- a/fs/overlayfs/util.c
+++ b/fs/overlayfs/util.c
@@ -225,11 +225,11 @@ void ovl_path_lower(struct dentry *dentry, struct path *path)
 void ovl_path_lowerdata(struct dentry *dentry, struct path *path)
 {
 	struct ovl_entry *oe = OVL_E(dentry);
-	struct ovl_path *lowerstack = ovl_lowerstack(oe);
+	struct ovl_path *lowerdata = ovl_lowerdata(oe);
 
 	if (ovl_numlower(oe)) {
-		path->mnt = lowerstack[ovl_numlower(oe) - 1].layer->mnt;
-		path->dentry = lowerstack[ovl_numlower(oe) - 1].dentry;
+		path->mnt = lowerdata->layer->mnt;
+		path->dentry = lowerdata->dentry;
 	} else {
 		*path = (struct path) { };
 	}
@@ -288,10 +288,7 @@ const struct ovl_layer *ovl_layer_lower(struct dentry *dentry)
  */
 struct dentry *ovl_dentry_lowerdata(struct dentry *dentry)
 {
-	struct ovl_entry *oe = OVL_E(dentry);
-
-	return ovl_numlower(oe) ?
-		ovl_lowerstack(oe)[ovl_numlower(oe) - 1].dentry : NULL;
+	return ovl_lowerdata_dentry(OVL_E(dentry));
 }
 
 struct dentry *ovl_dentry_real(struct dentry *dentry)
@@ -341,10 +338,12 @@ struct inode *ovl_inode_real(struct inode *inode)
 /* Return inode which contains lower data. Do not return metacopy */
 struct inode *ovl_inode_lowerdata(struct inode *inode)
 {
+	struct dentry *lowerdata = ovl_lowerdata_dentry(OVL_I_E(inode));
+
 	if (WARN_ON(!S_ISREG(inode->i_mode)))
 		return NULL;
 
-	return OVL_I(inode)->lowerdata ?: ovl_inode_lower(inode);
+	return lowerdata ? d_inode(lowerdata) : NULL;
 }
 
 /* Return real inode which contains data. Does not return metacopy inode */