[PATCH v2 25/25] vfs: return -EOPNOTSUPP for fscaps from vfs_*xattr()

["Seth Forshee (DigitalOcean)" <sforshee@kernel.org>]

Now that the new vfs-level interfaces are fully supported and all code
has been converted to use them, stop permitting use of the top-level vfs
xattr interfaces for capabilities xattrs. Unlike with ACLs we still need
to be able to work with fscaps xattrs using lower-level interfaces in a
handful of places, so only use of the top-level xattr interfaces is
restricted.

Signed-off-by: Seth Forshee (DigitalOcean) <sforshee@kernel.org>
---
 fs/xattr.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/fs/xattr.c b/fs/xattr.c
index 30eff6bc4f6d..2b8214c9534f 100644
--- a/fs/xattr.c
+++ b/fs/xattr.c
@@ -534,6 +534,9 @@ vfs_setxattr(struct mnt_idmap *idmap, struct dentry *dentry,
 	const void  *orig_value = value;
 	int error;
 
+	if (WARN_ON_ONCE(is_fscaps_xattr(name)))
+		return -EOPNOTSUPP;
+
 retry_deleg:
 	inode_lock(inode);
 	error = __vfs_setxattr_locked(idmap, dentry, name, value, size,
@@ -649,6 +652,9 @@ vfs_getxattr(struct mnt_idmap *idmap, struct dentry *dentry,
 	struct inode *inode = dentry->d_inode;
 	int error;
 
+	if (WARN_ON_ONCE(is_fscaps_xattr(name)))
+		return -EOPNOTSUPP;
+
 	error = xattr_permission(idmap, inode, name, MAY_READ);
 	if (error)
 		return error;
@@ -788,6 +794,9 @@ vfs_removexattr(struct mnt_idmap *idmap, struct dentry *dentry,
 	struct inode *delegated_inode = NULL;
 	int error;
 
+	if (WARN_ON_ONCE(is_fscaps_xattr(name)))
+		return -EOPNOTSUPP;
+
 retry_deleg:
 	inode_lock(inode);
 	error = __vfs_removexattr_locked(idmap, dentry,

-- 
2.43.0