Merge tag 'v6.4/vfs.acl' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull acl updates from Christian Brauner:
 "After finishing the introduction of the new posix acl api last cycle
  the generic POSIX ACL xattr handlers are still around in the
  filesystems xattr handlers for two reasons:

   (1) Because a few filesystems rely on the ->list() method of the
       generic POSIX ACL xattr handlers in their ->listxattr() inode
       operation.

   (2) POSIX ACLs are only available if IOP_XATTR is raised. The
       IOP_XATTR flag is raised in inode_init_always() based on whether
       the sb->s_xattr pointer is non-NULL. IOW, the registered xattr
       handlers of the filesystem are used to raise IOP_XATTR. Removing
       the generic POSIX ACL xattr handlers from all filesystems would
       risk regressing filesystems that only implement POSIX ACL support
       and no other xattrs (nfs3 comes to mind).

  This contains the work to decouple POSIX ACLs from the IOP_XATTR flag
  as they don't depend on xattr handlers anymore. So it's now possible
  to remove the generic POSIX ACL xattr handlers from the sb->s_xattr
  list of all filesystems. This is a crucial step as the generic POSIX
  ACL xattr handlers aren't used for POSIX ACLs anymore and POSIX ACLs
  don't depend on the xattr infrastructure anymore.

  Adressing problem (1) will require more long-term work. It would be
  best to get rid of the ->list() method of xattr handlers completely at
  some point.

  For erofs, ext{2,4}, f2fs, jffs2, ocfs2, and reiserfs the nop POSIX
  ACL xattr handler is kept around so they can continue to use
  array-based xattr handler indexing.

  This update does simplify the ->listxattr() implementation of all
  these filesystems however"

* tag 'v6.4/vfs.acl' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
  acl: don't depend on IOP_XATTR
  ovl: check for ->listxattr() support
  reiserfs: rework priv inode handling
  fs: rename generic posix acl handlers
  reiserfs: rework ->listxattr() implementation
  fs: simplify ->listxattr() implementation
  fs: drop unused posix acl handlers
  xattr: remove unused argument
  xattr: add listxattr helper
  xattr: simplify listxattr helpers

2 files changed, 15 insertions, 17 deletions

diff --git a/fs/erofs/xattr.c b/fs/erofs/xattr.c
index 60729b1220b6..015462763bdd 100644
--- a/fs/erofs/xattr.c
+++ b/fs/erofs/xattr.c
@@ -463,10 +463,6 @@ const struct xattr_handler __maybe_unused erofs_xattr_security_handler = {
 
 const struct xattr_handler *erofs_xattr_handlers[] = {
 	&erofs_xattr_user_handler,
-#ifdef CONFIG_EROFS_FS_POSIX_ACL
-	&posix_acl_access_xattr_handler,
-	&posix_acl_default_xattr_handler,
-#endif
 	&erofs_xattr_trusted_handler,
 #ifdef CONFIG_EROFS_FS_SECURITY
 	&erofs_xattr_security_handler,
@@ -490,13 +486,9 @@ static int xattr_entrylist(struct xattr_iter *_it,
 	unsigned int prefix_len;
 	const char *prefix;
 
-	const struct xattr_handler *h =
-		erofs_xattr_handler(entry->e_name_index);
-
-	if (!h || (h->list && !h->list(it->dentry)))
+	prefix = erofs_xattr_prefix(entry->e_name_index, it->dentry);
+	if (!prefix)
 		return 1;
-
-	prefix = xattr_prefix(h);
 	prefix_len = strlen(prefix);
 
 	if (!it->buffer) {
diff --git a/fs/erofs/xattr.h b/fs/erofs/xattr.h
index 0a43c9ee9f8f..97185cb649b6 100644
--- a/fs/erofs/xattr.h
+++ b/fs/erofs/xattr.h
@@ -41,15 +41,16 @@ extern const struct xattr_handler erofs_xattr_user_handler;
 extern const struct xattr_handler erofs_xattr_trusted_handler;
 extern const struct xattr_handler erofs_xattr_security_handler;
 
-static inline const struct xattr_handler *erofs_xattr_handler(unsigned int idx)
+static inline const char *erofs_xattr_prefix(unsigned int idx,
+					     struct dentry *dentry)
 {
+	const struct xattr_handler *handler = NULL;
+
 	static const struct xattr_handler *xattr_handler_map[] = {
 		[EROFS_XATTR_INDEX_USER] = &erofs_xattr_user_handler,
 #ifdef CONFIG_EROFS_FS_POSIX_ACL
-		[EROFS_XATTR_INDEX_POSIX_ACL_ACCESS] =
-			&posix_acl_access_xattr_handler,
-		[EROFS_XATTR_INDEX_POSIX_ACL_DEFAULT] =
-			&posix_acl_default_xattr_handler,
+		[EROFS_XATTR_INDEX_POSIX_ACL_ACCESS] = &nop_posix_acl_access,
+		[EROFS_XATTR_INDEX_POSIX_ACL_DEFAULT] = &nop_posix_acl_default,
 #endif
 		[EROFS_XATTR_INDEX_TRUSTED] = &erofs_xattr_trusted_handler,
 #ifdef CONFIG_EROFS_FS_SECURITY
@@ -57,8 +58,13 @@ static inline const struct xattr_handler *erofs_xattr_handler(unsigned int idx)
 #endif
 	};
 
-	return idx && idx < ARRAY_SIZE(xattr_handler_map) ?
-		xattr_handler_map[idx] : NULL;
+	if (idx && idx < ARRAY_SIZE(xattr_handler_map))
+		handler = xattr_handler_map[idx];
+
+	if (!xattr_handler_can_list(handler, dentry))
+		return NULL;
+
+	return xattr_prefix(handler);
 }
 
 extern const struct xattr_handler *erofs_xattr_handlers[];