X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?p=pandora-kernel.git;a=blobdiff_plain;f=fs%2Fposix_acl.c;h=0ff20797e162790aeadca20fe1a1caca3a495302;hp=cea4623f1ed63007b8da0a8486ac65595415f895;hb=HEAD;hpb=daedd8708fe7707ed651bb1c83162f25c48a947c

diff --git a/fs/posix_acl.c b/fs/posix_acl.c
index cea4623f1ed6..0ff20797e162 100644
--- a/fs/posix_acl.c
+++ b/fs/posix_acl.c
@@ -155,6 +155,12 @@ posix_acl_equiv_mode(const struct posix_acl *acl, umode_t *mode_p)
 	umode_t mode = 0;
 	int not_equiv = 0;
 
+	/*
+	 * A null ACL can always be presented as mode bits.
+	 */
+	if (!acl)
+		return 0;
+
 	FOREACH_ACL_ENTRY(pa, acl, pe) {
 		switch (pa->e_tag) {
 			case ACL_USER_OBJ:
@@ -335,6 +341,36 @@ static int posix_acl_create_masq(struct posix_acl *acl, umode_t *mode_p)
         return not_equiv;
 }
 
+/**
+ * posix_acl_update_mode  -  update mode in set_acl
+ *
+ * Update the file mode when setting an ACL: compute the new file permission
+ * bits based on the ACL.  In addition, if the ACL is equivalent to the new
+ * file mode, set *acl to NULL to indicate that no ACL should be set.
+ *
+ * As with chmod, clear the setgit bit if the caller is not in the owning group
+ * or capable of CAP_FSETID (see inode_change_ok).
+ *
+ * Called from set_acl inode operations.
+ */
+int posix_acl_update_mode(struct inode *inode, umode_t *mode_p,
+			  struct posix_acl **acl)
+{
+	umode_t mode = inode->i_mode;
+	int error;
+
+	error = posix_acl_equiv_mode(*acl, &mode);
+	if (error < 0)
+		return error;
+	if (error == 0)
+		*acl = NULL;
+	if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID))
+		mode &= ~S_ISGID;
+	*mode_p = mode;
+	return 0;
+}
+EXPORT_SYMBOL(posix_acl_update_mode);
+
 /*
  * Modify the ACL for the chmod syscall.
  */