[PATCH v3 2/7] overlayfs: Convert to super_set_uuid()

[Kent Overstreet <kent.overstreet@linux.dev>]

We don't want to be settingc sb->s_uuid directly anymore, as there's a
length field that also has to be set, and this conversion was not
completely trivial.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Miklos Szeredi <miklos@szeredi.hu>
Cc: Amir Goldstein <amir73il@gmail.com>
Cc: linux-unionfs@vger.kernel.org
---
 fs/overlayfs/util.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c
index 0217094c23ea..f1f0ee9a9dff 100644
--- a/fs/overlayfs/util.c
+++ b/fs/overlayfs/util.c
@@ -760,13 +760,14 @@ bool ovl_init_uuid_xattr(struct super_block *sb, struct ovl_fs *ofs,
 			 const struct path *upperpath)
 {
 	bool set = false;
+	uuid_t uuid;
 	int res;
 
 	/* Try to load existing persistent uuid */
-	res = ovl_path_getxattr(ofs, upperpath, OVL_XATTR_UUID, sb->s_uuid.b,
+	res = ovl_path_getxattr(ofs, upperpath, OVL_XATTR_UUID, uuid.b,
 				UUID_SIZE);
 	if (res == UUID_SIZE)
-		return true;
+		goto success;
 
 	if (res != -ENODATA)
 		goto fail;
@@ -794,14 +795,14 @@ bool ovl_init_uuid_xattr(struct super_block *sb, struct ovl_fs *ofs,
 	}
 
 	/* Generate overlay instance uuid */
-	uuid_gen(&sb->s_uuid);
+	uuid_gen(&uuid);
 
 	/* Try to store persistent uuid */
 	set = true;
-	res = ovl_setxattr(ofs, upperpath->dentry, OVL_XATTR_UUID, sb->s_uuid.b,
+	res = ovl_setxattr(ofs, upperpath->dentry, OVL_XATTR_UUID, uuid.b,
 			   UUID_SIZE);
 	if (res == 0)
-		return true;
+		goto success;
 
 fail:
 	memset(sb->s_uuid.b, 0, UUID_SIZE);
@@ -809,6 +810,9 @@ bool ovl_init_uuid_xattr(struct super_block *sb, struct ovl_fs *ofs,
 	pr_warn("failed to %s uuid (%pd2, err=%i); falling back to uuid=null.\n",
 		set ? "set" : "get", upperpath->dentry, res);
 	return false;
+success:
+	super_set_uuid(sb, uuid.b, sizeof(uuid));
+	return true;
 }
 
 bool ovl_path_check_dir_xattr(struct ovl_fs *ofs, const struct path *path,
-- 
2.43.0