f2fs: support FS_IOC_{GET,SET}FSLABEL

[sfrench/cifs-2.6.git] / fs / open.c

diff --git a/fs/open.c b/fs/open.c
index b5b80469b93d05ce034cd85cf95da35dc37e13c2..a59abe3c669ae13ac7f3fa68bc0fb5f54a781ee4 100644 (file)
--- a/fs/open.c
+++ b/fs/open.c
@@ -374,6 +374,25 @@ long do_faccessat(int dfd, const char __user *filename, int mode)
                                override_cred->cap_permitted;
        }
 
+       /*
+        * The new set of credentials can *only* be used in
+        * task-synchronous circumstances, and does not need
+        * RCU freeing, unless somebody then takes a separate
+        * reference to it.
+        *
+        * NOTE! This is _only_ true because this credential
+        * is used purely for override_creds() that installs
+        * it as the subjective cred. Other threads will be
+        * accessing ->real_cred, not the subjective cred.
+        *
+        * If somebody _does_ make a copy of this (using the
+        * 'get_current_cred()' function), that will clear the
+        * non_rcu field, because now that other user may be
+        * expecting RCU freeing. But normal thread-synchronous
+        * cred accesses will keep things non-RCY.
+        */
+       override_cred->non_rcu = 1;
+
        old_cred = override_creds(override_cred);
 retry:
        res = user_path_at(dfd, filename, lookup_flags, &path);