Merge tag 'ovl-fixes-5.19-rc7' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs into fs.idmapped.overlay.acl

Bring in Miklos' tree which contains the temporary fix for POSIX ACLs
with overlayfs on top of idmapped layers. We will add a proper fix on
top of it and then revert the temporary fix.

Cc: Seth Forshee <sforshee@digitalocean.com>
Cc: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>

1 files changed, 24 insertions, 1 deletions

diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index e0a2e0468ee7..1ce5c9698393 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -1003,6 +1003,9 @@ ovl_posix_acl_xattr_get(const struct xattr_handler *handler,
 			struct dentry *dentry, struct inode *inode,
 			const char *name, void *buffer, size_t size)
 {
+	if (!IS_POSIXACL(inode))
+		return -EOPNOTSUPP;
+
 	return ovl_xattr_get(dentry, inode, handler->name, buffer, size);
 }
 
@@ -1018,6 +1021,9 @@ ovl_posix_acl_xattr_set(const struct xattr_handler *handler,
 	struct posix_acl *acl = NULL;
 	int err;
 
+	if (!IS_POSIXACL(inode))
+		return -EOPNOTSUPP;
+
 	/* Check that everything is OK before copy-up */
 	if (value) {
 		acl = posix_acl_from_xattr(&init_user_ns, value, size);
@@ -1960,6 +1966,20 @@ static struct dentry *ovl_get_root(struct super_block *sb,
 	return root;
 }
 
+static bool ovl_has_idmapped_layers(struct ovl_fs *ofs)
+{
+
+	unsigned int i;
+	const struct vfsmount *mnt;
+
+	for (i = 0; i < ofs->numlayer; i++) {
+		mnt = ofs->layers[i].mnt;
+		if (mnt && is_idmapped_mnt(mnt))
+			return true;
+	}
+	return false;
+}
+
 static int ovl_fill_super(struct super_block *sb, void *data, int silent)
 {
 	struct path upperpath = { };
@@ -2129,7 +2149,10 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
 	sb->s_xattr = ofs->config.userxattr ? ovl_user_xattr_handlers :
 		ovl_trusted_xattr_handlers;
 	sb->s_fs_info = ofs;
-	sb->s_flags |= SB_POSIXACL;
+	if (ovl_has_idmapped_layers(ofs))
+		pr_warn("POSIX ACLs are not yet supported with idmapped layers, mounting without ACL support.\n");
+	else
+		sb->s_flags |= SB_POSIXACL;
 	sb->s_iflags |= SB_I_SKIP_SYNC;
 
 	err = -ENOMEM;