[PATCH] Fix posix file locking (1/9)

VFS: Fix up posix_same_owner() so that it only uses the
   file_lock->fl_owner field when determining lock equality.

VFS: Fix up posix locking routines to use posix_same_owner() instead
   of rolling their own checks.

Signed-off-by: Trond Myklebust <trond.myklebust@fys.uio.no>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/fs/locks.c b/fs/locks.c
index 0204acb9f0db58970aa44434a7924c88235b72e5..b0e47577cf08f58e37bc09e54ba81666428189de 100644 (file)
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -414,14 +414,16 @@ static inline int locks_overlap(struct file_lock *fl1, struct file_lock *fl2)
 }
 
 /*
- * Check whether two locks have the same owner.  The apparently superfluous
- * check for fl_pid enables us to distinguish between locks set by lockd.
+ * Check whether two locks have the same owner.
  */
 static inline int
 posix_same_owner(struct file_lock *fl1, struct file_lock *fl2)
 {
-       return (fl1->fl_owner == fl2->fl_owner) &&
-               (fl1->fl_pid == fl2->fl_pid);
+       /* FIXME: Replace this sort of thing with struct file_lock_operations */
+       if ((fl1->fl_type | fl2->fl_type) & FL_LOCKD)
+               return fl1->fl_owner == fl2->fl_owner &&
+                       fl1->fl_pid == fl2->fl_pid;
+       return fl1->fl_owner == fl2->fl_owner;
 }
 
 /* Remove waiter from blocker's block list.
@@ -631,24 +633,15 @@ int posix_locks_deadlock(struct file_lock *caller_fl,
                                struct file_lock *block_fl)
 {
        struct list_head *tmp;
-       fl_owner_t caller_owner, blocked_owner;
-       unsigned int     caller_pid, blocked_pid;
-
-       caller_owner = caller_fl->fl_owner;
-       caller_pid = caller_fl->fl_pid;
-       blocked_owner = block_fl->fl_owner;
-       blocked_pid = block_fl->fl_pid;
 
 next_task:
-       if (caller_owner == blocked_owner && caller_pid == blocked_pid)
+       if (posix_same_owner(caller_fl, block_fl))
                return 1;
        list_for_each(tmp, &blocked_list) {
                struct file_lock *fl = list_entry(tmp, struct file_lock, fl_link);
-               if ((fl->fl_owner == blocked_owner)
-                   && (fl->fl_pid == blocked_pid)) {
+               if (posix_same_owner(fl, block_fl)) {
                        fl = fl->fl_next;
-                       blocked_owner = fl->fl_owner;
-                       blocked_pid = fl->fl_pid;
+                       block_fl = fl;
                        goto next_task;
                }
        }
@@ -1684,7 +1677,7 @@ void locks_remove_posix(struct file *filp, fl_owner_t owner)
        lock_kernel();
        while (*before != NULL) {
                struct file_lock *fl = *before;
-               if (IS_POSIX(fl) && (fl->fl_owner == owner)) {
+               if (IS_POSIX(fl) && posix_same_owner(fl, &lock)) {
                        locks_delete_lock(before);
                        continue;
                }