vfs: add a comment to inode_permission()

Acked-by: J. Bruce Fields <bfields@redhat.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruen@kernel.org>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
diff --git a/fs/namei.c b/fs/namei.c
index 276cd30..9061157 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -221,7 +221,7 @@
 }
 
 /*
- * This does basic POSIX ACL permission checking
+ * This does the basic permission checking
  */
 static int acl_permission_check(struct inode *inode, int mask)
 {
@@ -271,7 +271,7 @@
 	int ret;
 
 	/*
-	 * Do the basic POSIX ACL permission checks.
+	 * Do the basic permission checks.
 	 */
 	ret = acl_permission_check(inode, mask);
 	if (ret != -EACCES)
@@ -335,6 +335,8 @@
  * We use "fsuid" for this, letting us set arbitrary permissions
  * for filesystem access without changing the "normal" uids which
  * are used for other things.
+ *
+ * When checking for MAY_APPEND, MAY_WRITE must also be set in @mask.
  */
 int inode_permission(struct inode *inode, int mask)
 {