4 files changed, 26 insertions, 2 deletions

diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c
index 3380039036d6..0b7e7a90a435 100644
--- a/fs/overlayfs/copy_up.c
+++ b/fs/overlayfs/copy_up.c
@@ -320,7 +320,8 @@ struct ovl_fh *ovl_encode_real_fh(struct ovl_fs *ofs, struct dentry *real,
 	if (is_upper)
 		fh->fb.flags |= OVL_FH_FLAG_PATH_UPPER;
 	fh->fb.len = sizeof(fh->fb) + buflen;
-	fh->fb.uuid = *uuid;
+	if (ofs->config.uuid)
+		fh->fb.uuid = *uuid;
 
 	return fh;
 
diff --git a/fs/overlayfs/namei.c b/fs/overlayfs/namei.c
index f058bf8e8b87..f731eb4d35f9 100644
--- a/fs/overlayfs/namei.c
+++ b/fs/overlayfs/namei.c
@@ -159,8 +159,10 @@ struct dentry *ovl_decode_real_fh(struct ovl_fs *ofs, struct ovl_fh *fh,
 	/*
 	 * Make sure that the stored uuid matches the uuid of the lower
 	 * layer where file handle will be decoded.
+	 * In case of uuid=off option just make sure that stored uuid is null.
 	 */
-	if (!uuid_equal(&fh->fb.uuid, &mnt->mnt_sb->s_uuid))
+	if (ofs->config.uuid ? !uuid_equal(&fh->fb.uuid, &mnt->mnt_sb->s_uuid) :
+			      !uuid_is_null(&fh->fb.uuid))
 		return NULL;
 
 	bytes = (fh->fb.len - offsetof(struct ovl_fb, fid));
diff --git a/fs/overlayfs/ovl_entry.h b/fs/overlayfs/ovl_entry.h
index 1b5a2094df8e..b7a73ea147b8 100644
--- a/fs/overlayfs/ovl_entry.h
+++ b/fs/overlayfs/ovl_entry.h
@@ -14,6 +14,7 @@ struct ovl_config {
 	bool redirect_follow;
 	const char *redirect_mode;
 	bool index;
+	bool uuid;
 	bool nfs_export;
 	int xino;
 	bool metacopy;
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index 290983bcfbb3..4717244e7d7a 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -356,6 +356,8 @@ static int ovl_show_options(struct seq_file *m, struct dentry *dentry)
 		seq_printf(m, ",redirect_dir=%s", ofs->config.redirect_mode);
 	if (ofs->config.index != ovl_index_def)
 		seq_printf(m, ",index=%s", ofs->config.index ? "on" : "off");
+	if (!ofs->config.uuid)
+		seq_puts(m, ",uuid=off");
 	if (ofs->config.nfs_export != ovl_nfs_export_def)
 		seq_printf(m, ",nfs_export=%s", ofs->config.nfs_export ?
 						"on" : "off");
@@ -410,6 +412,8 @@ enum {
 	OPT_REDIRECT_DIR,
 	OPT_INDEX_ON,
 	OPT_INDEX_OFF,
+	OPT_UUID_ON,
+	OPT_UUID_OFF,
 	OPT_NFS_EXPORT_ON,
 	OPT_NFS_EXPORT_OFF,
 	OPT_XINO_ON,
@@ -429,6 +433,8 @@ static const match_table_t ovl_tokens = {
 	{OPT_REDIRECT_DIR,		"redirect_dir=%s"},
 	{OPT_INDEX_ON,			"index=on"},
 	{OPT_INDEX_OFF,			"index=off"},
+	{OPT_UUID_ON,			"uuid=on"},
+	{OPT_UUID_OFF,			"uuid=off"},
 	{OPT_NFS_EXPORT_ON,		"nfs_export=on"},
 	{OPT_NFS_EXPORT_OFF,		"nfs_export=off"},
 	{OPT_XINO_ON,			"xino=on"},
@@ -549,6 +555,14 @@ static int ovl_parse_opt(char *opt, struct ovl_config *config)
 			index_opt = true;
 			break;
 
+		case OPT_UUID_ON:
+			config->uuid = true;
+			break;
+
+		case OPT_UUID_OFF:
+			config->uuid = false;
+			break;
+
 		case OPT_NFS_EXPORT_ON:
 			config->nfs_export = true;
 			nfs_export_opt = true;
@@ -1877,6 +1891,7 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
 	ofs->share_whiteout = true;
 
 	ofs->config.index = ovl_index_def;
+	ofs->config.uuid = true;
 	ofs->config.nfs_export = ovl_nfs_export_def;
 	ofs->config.xino = ovl_xino_def();
 	ofs->config.metacopy = ovl_metacopy_def;
@@ -1956,6 +1971,11 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
 	if (!ovl_upper_mnt(ofs))
 		sb->s_flags |= SB_RDONLY;
 
+	if (!ofs->config.uuid && ofs->numfs > 1) {
+		pr_warn("The uuid=off requires a single fs for lower and upper, falling back to uuid=on.\n");
+		ofs->config.uuid = true;
+	}
+
 	if (!ovl_force_readonly(ofs) && ofs->config.index) {
 		err = ovl_get_indexdir(sb, ofs, oe, &upperpath);
 		if (err)