ovl: add accessor for ofs->upper_mnt

Next patch will remove ofs->upper_mnt, so add an accessor function for this
field.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

fs/overlayfs/export.c

@@ -204,7 +204,7 @@ static int ovl_check_encode_origin(struct dentry *dentry)
 	 * ovl_connect_layer() will try to make origin's layer "connected" by
 	 * copying up a "connectable" ancestor.
 	 */
-	if (d_is_dir(dentry) && ofs->upper_mnt)
+	if (d_is_dir(dentry) && ovl_upper_mnt(ofs))
 		return ovl_connect_layer(dentry);
 
 	/* Lower file handle for indexed and non-upper dir/non-dir */
@@ -677,10 +677,10 @@ static struct dentry *ovl_upper_fh_to_d(struct super_block *sb,
 	struct dentry *dentry;
 	struct dentry *upper;
 
-	if (!ofs->upper_mnt)
+	if (!ovl_upper_mnt(ofs))
 		return ERR_PTR(-EACCES);
 
-	upper = ovl_decode_real_fh(fh, ofs->upper_mnt, true);
+	upper = ovl_decode_real_fh(fh, ovl_upper_mnt(ofs), true);
 	if (IS_ERR_OR_NULL(upper))
 		return upper;
 

fs/overlayfs/inode.c

@@ -456,7 +456,7 @@ int ovl_update_time(struct inode *inode, struct timespec64 *ts, int flags)
 	if (flags & S_ATIME) {
 		struct ovl_fs *ofs = inode->i_sb->s_fs_info;
 		struct path upperpath = {
-			.mnt = ofs->upper_mnt,
+			.mnt = ovl_upper_mnt(ofs),
 			.dentry = ovl_upperdentry_dereference(OVL_I(inode)),
 		};
 
@@ -921,7 +921,7 @@ static bool ovl_hash_bylower(struct super_block *sb, struct dentry *upper,
 		return true;
 
 	/* Yes, if won't be copied up */
-	if (!ofs->upper_mnt)
+	if (!ovl_upper_mnt(ofs))
 		return true;
 
 	/* No, if lower hardlink is or will be broken on copy up */

fs/overlayfs/namei.c

@@ -489,7 +489,7 @@ struct dentry *ovl_index_upper(struct ovl_fs *ofs, struct dentry *index)
 	if (IS_ERR_OR_NULL(fh))
 		return ERR_CAST(fh);
 
-	upper = ovl_decode_real_fh(fh, ofs->upper_mnt, true);
+	upper = ovl_decode_real_fh(fh, ovl_upper_mnt(ofs), true);
 	kfree(fh);
 
 	if (IS_ERR_OR_NULL(upper))

fs/overlayfs/ovl_entry.h

@@ -82,6 +82,11 @@ struct ovl_fs {
 	struct dentry *whiteout;
 };
 
+static inline struct vfsmount *ovl_upper_mnt(struct ovl_fs *ofs)
+{
+	return ofs->upper_mnt;
+}
+
 static inline struct ovl_fs *OVL_FS(struct super_block *sb)
 {
 	return (struct ovl_fs *)sb->s_fs_info;

fs/overlayfs/readdir.c

@@ -1120,7 +1120,7 @@ int ovl_indexdir_cleanup(struct ovl_fs *ofs)
 	struct dentry *indexdir = ofs->indexdir;
 	struct dentry *index = NULL;
 	struct inode *dir = indexdir->d_inode;
-	struct path path = { .mnt = ofs->upper_mnt, .dentry = indexdir };
+	struct path path = { .mnt = ovl_upper_mnt(ofs), .dentry = indexdir };
 	LIST_HEAD(list);
 	struct rb_root root = RB_ROOT;
 	struct ovl_cache_entry *p;

fs/overlayfs/super.c

@@ -224,7 +224,7 @@ static void ovl_free_fs(struct ovl_fs *ofs)
 		ovl_inuse_unlock(ofs->workbasedir);
 	dput(ofs->workbasedir);
 	if (ofs->upperdir_locked)
-		ovl_inuse_unlock(ofs->upper_mnt->mnt_root);
+		ovl_inuse_unlock(ovl_upper_mnt(ofs)->mnt_root);
 	mntput(ofs->upper_mnt);
 	for (i = 1; i < ofs->numlayer; i++) {
 		iput(ofs->layers[i].trap);
@@ -258,7 +258,7 @@ static int ovl_sync_fs(struct super_block *sb, int wait)
 	struct super_block *upper_sb;
 	int ret;
 
-	if (!ofs->upper_mnt)
+	if (!ovl_upper_mnt(ofs))
 		return 0;
 
 	/*
@@ -272,7 +272,7 @@ static int ovl_sync_fs(struct super_block *sb, int wait)
 	if (!wait)
 		return 0;
 
-	upper_sb = ofs->upper_mnt->mnt_sb;
+	upper_sb = ovl_upper_mnt(ofs)->mnt_sb;
 
 	down_read(&upper_sb->s_umount);
 	ret = sync_filesystem(upper_sb);
@@ -310,7 +310,7 @@ static int ovl_statfs(struct dentry *dentry, struct kstatfs *buf)
 /* Will this overlay be forced to mount/remount ro? */
 static bool ovl_force_readonly(struct ovl_fs *ofs)
 {
-	return (!ofs->upper_mnt || !ofs->workdir);
+	return (!ovl_upper_mnt(ofs) || !ofs->workdir);
 }
 
 static const char *ovl_redirect_mode_def(void)
@@ -372,7 +372,7 @@ static int ovl_remount(struct super_block *sb, int *flags, char *data)
 		return -EROFS;
 
 	if (*flags & SB_RDONLY && !sb_rdonly(sb)) {
-		upper_sb = ofs->upper_mnt->mnt_sb;
+		upper_sb = ovl_upper_mnt(ofs)->mnt_sb;
 		down_read(&upper_sb->s_umount);
 		ret = sync_filesystem(upper_sb);
 		up_read(&upper_sb->s_umount);
@@ -669,7 +669,7 @@ static struct dentry *ovl_workdir_create(struct ovl_fs *ofs,
 					 const char *name, bool persist)
 {
 	struct inode *dir =  ofs->workbasedir->d_inode;
-	struct vfsmount *mnt = ofs->upper_mnt;
+	struct vfsmount *mnt = ovl_upper_mnt(ofs);
 	struct dentry *work;
 	int err;
 	bool retried = false;
@@ -1122,7 +1122,7 @@ static int ovl_get_upper(struct super_block *sb, struct ovl_fs *ofs,
 	if (upper_mnt->mnt_sb->s_flags & SB_NOSEC)
 		sb->s_flags |= SB_NOSEC;
 
-	if (ovl_inuse_trylock(ofs->upper_mnt->mnt_root)) {
+	if (ovl_inuse_trylock(ovl_upper_mnt(ofs)->mnt_root)) {
 		ofs->upperdir_locked = true;
 	} else {
 		err = ovl_report_in_use(ofs, "upperdir");
@@ -1198,7 +1198,7 @@ static int ovl_check_rename_whiteout(struct dentry *workdir)
 static int ovl_make_workdir(struct super_block *sb, struct ovl_fs *ofs,
 			    struct path *workpath)
 {
-	struct vfsmount *mnt = ofs->upper_mnt;
+	struct vfsmount *mnt = ovl_upper_mnt(ofs);
 	struct dentry *temp;
 	bool rename_whiteout;
 	bool d_type;
@@ -1342,7 +1342,7 @@ static int ovl_get_workdir(struct super_block *sb, struct ovl_fs *ofs,
 static int ovl_get_indexdir(struct super_block *sb, struct ovl_fs *ofs,
 			    struct ovl_entry *oe, struct path *upperpath)
 {
-	struct vfsmount *mnt = ofs->upper_mnt;
+	struct vfsmount *mnt = ovl_upper_mnt(ofs);
 	int err;
 
 	err = mnt_want_write(mnt);
@@ -1398,7 +1398,7 @@ static bool ovl_lower_uuid_ok(struct ovl_fs *ofs, const uuid_t *uuid)
 {
 	unsigned int i;
 
-	if (!ofs->config.nfs_export && !ofs->upper_mnt)
+	if (!ofs->config.nfs_export && !ovl_upper_mnt(ofs))
 		return true;
 
 	for (i = 0; i < ofs->numfs; i++) {
@@ -1477,7 +1477,7 @@ static int ovl_get_layers(struct super_block *sb, struct ovl_fs *ofs,
 	/* idx/fsid 0 are reserved for upper fs even with lower only overlay */
 	ofs->numfs++;
 
-	layers[0].mnt = ofs->upper_mnt;
+	layers[0].mnt = ovl_upper_mnt(ofs);
 	layers[0].idx = 0;
 	layers[0].fsid = 0;
 	ofs->numlayer = 1;
@@ -1494,8 +1494,8 @@ static int ovl_get_layers(struct super_block *sb, struct ovl_fs *ofs,
 		goto out;
 	}
 
-	if (ofs->upper_mnt) {
-		ofs->fs[0].sb = ofs->upper_mnt->mnt_sb;
+	if (ovl_upper_mnt(ofs)) {
+		ofs->fs[0].sb = ovl_upper_mnt(ofs)->mnt_sb;
 		ofs->fs[0].is_lower = false;
 	}
 
@@ -1550,7 +1550,7 @@ static int ovl_get_layers(struct super_block *sb, struct ovl_fs *ofs,
 	 * inode number or a non persistent inode number allocated from a
 	 * dedicated range.
 	 */
-	if (ofs->numfs - !ofs->upper_mnt == 1) {
+	if (ofs->numfs - !ovl_upper_mnt(ofs) == 1) {
 		if (ofs->config.xino == OVL_XINO_ON)
 			pr_info("\"xino=on\" is useless with all layers on same fs, ignore.\n");
 		ofs->xino_mode = 0;
@@ -1699,8 +1699,8 @@ static int ovl_check_overlapping_layers(struct super_block *sb,
 {
 	int i, err;
 
-	if (ofs->upper_mnt) {
-		err = ovl_check_layer(sb, ofs, ofs->upper_mnt->mnt_root,
+	if (ovl_upper_mnt(ofs)) {
+		err = ovl_check_layer(sb, ofs, ovl_upper_mnt(ofs)->mnt_root,
 				      "upperdir");
 		if (err)
 			return err;
@@ -1836,8 +1836,8 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
 		if (!ofs->workdir)
 			sb->s_flags |= SB_RDONLY;
 
-		sb->s_stack_depth = ofs->upper_mnt->mnt_sb->s_stack_depth;
-		sb->s_time_gran = ofs->upper_mnt->mnt_sb->s_time_gran;
+		sb->s_stack_depth = ovl_upper_mnt(ofs)->mnt_sb->s_stack_depth;
+		sb->s_time_gran = ovl_upper_mnt(ofs)->mnt_sb->s_time_gran;
 
 	}
 	oe = ovl_get_lowerstack(sb, ofs);
@@ -1846,7 +1846,7 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
 		goto out_err;
 
 	/* If the upper fs is nonexistent, we mark overlayfs r/o too */
-	if (!ofs->upper_mnt)
+	if (!ovl_upper_mnt(ofs))
 		sb->s_flags |= SB_RDONLY;
 
 	if (!(ovl_force_readonly(ofs)) && ofs->config.index) {
@@ -1874,7 +1874,7 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
 	/* Show index=off in /proc/mounts for forced r/o mount */
 	if (!ofs->indexdir) {
 		ofs->config.index = false;
-		if (ofs->upper_mnt && ofs->config.nfs_export) {
+		if (ovl_upper_mnt(ofs) && ofs->config.nfs_export) {
 			pr_warn("NFS export requires an index dir, falling back to nfs_export=off.\n");
 			ofs->config.nfs_export = false;
 		}

fs/overlayfs/util.c

@@ -18,13 +18,13 @@
 int ovl_want_write(struct dentry *dentry)
 {
 	struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
-	return mnt_want_write(ofs->upper_mnt);
+	return mnt_want_write(ovl_upper_mnt(ofs));
 }
 
 void ovl_drop_write(struct dentry *dentry)
 {
 	struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
-	mnt_drop_write(ofs->upper_mnt);
+	mnt_drop_write(ovl_upper_mnt(ofs));
 }
 
 struct dentry *ovl_workdir(struct dentry *dentry)
@@ -150,7 +150,7 @@ void ovl_path_upper(struct dentry *dentry, struct path *path)
 {
 	struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
 
-	path->mnt = ofs->upper_mnt;
+	path->mnt = ovl_upper_mnt(ofs);
 	path->dentry = ovl_dentry_upper(dentry);
 }