[PATCH] sleeping file locks

 - Add FL_SLEEP flag to indicate we intend to sleep and therefore desire
   to be placed on the block list.  Use it for POSIX & flock locks.
 - Remove locks_block_on.
 - Change posix_unblock_lock to eliminate a race that will appear once we
   don't use the BKL any more.
 - Update the comment for locks_same_owner() and rename it to
   posix_same_owner().
 - Change locks_mandatory_area() to allocate its lock on the stack and
   call posix_lock_file() instead of repeating that logic.
 - Rename the "caller" parameter to posix_lock_file() to "request"
   to better show that this is not to be inserted directly.
 - Redo some of the proc code a little.  Stop exposing kernel addresses
   to userspace (whoever thought _that_ was a good idea?!) and show how
   we should be printing the device name.  The last part is ifdeffed
   out to avoid breaking lslk.
 - Remove FL_BROKEN.  And there was much rejoicing.

fs/lockd/svclock.c

@@ -237,17 +237,8 @@ nlmsvc_delete_block(struct nlm_block *block, int unlock)
 
 	/* Remove block from list */
 	nlmsvc_remove_block(block);
-
-	/* If granted, unlock it, else remove from inode block list */
-	if (unlock && block->b_granted) {
-		dprintk("lockd: deleting granted lock\n");
-		fl->fl_type = F_UNLCK;
-		posix_lock_file(&block->b_file->f_file, fl, 0);
-		block->b_granted = 0;
-	} else {
-		dprintk("lockd: unblocking blocked lock\n");
-		posix_unblock_lock(fl);
-	}
+	posix_unblock_lock(&file->f_file, fl);
+	block->b_granted = 0;
 
 	/* If the block is in the middle of a GRANT callback,
 	 * don't kill it yet. */
@@ -324,7 +315,7 @@ nlmsvc_lock(struct svc_rqst *rqstp, struct nlm_file *file,
 
 again:
 	if (!(conflock = posix_test_lock(&file->f_file, &lock->fl))) {
-		error = posix_lock_file(&file->f_file, &lock->fl, 0);
+		error = posix_lock_file(&file->f_file, &lock->fl);
 
 		if (block)
 			nlmsvc_delete_block(block, 0);
@@ -428,7 +419,7 @@ nlmsvc_unlock(struct nlm_file *file, struct nlm_lock *lock)
 	nlmsvc_cancel_blocked(file, lock);
 
 	lock->fl.fl_type = F_UNLCK;
-	error = posix_lock_file(&file->f_file, &lock->fl, 0);
+	error = posix_lock_file(&file->f_file, &lock->fl);
 
 	return (error < 0)? nlm_lck_denied_nolocks : nlm_granted;
 }
@@ -532,7 +523,7 @@ nlmsvc_grant_blocked(struct nlm_block *block)
 	 * following yields an error, this is most probably due to low
 	 * memory. Retry the lock in a few seconds.
 	 */
-	if ((error = posix_lock_file(&file->f_file, &lock->fl, 0)) < 0) {
+	if ((error = posix_lock_file(&file->f_file, &lock->fl)) < 0) {
 		printk(KERN_WARNING "lockd: unexpected error %d in %s!\n",
 				-error, __FUNCTION__);
 		nlmsvc_insert_block(block, 10 * HZ);

fs/lockd/svcsubs.c

@@ -176,7 +176,7 @@ nlm_traverse_locks(struct nlm_host *host, struct nlm_file *file, int action)
 			lock.fl_type  = F_UNLCK;
 			lock.fl_start = 0;
 			lock.fl_end   = OFFSET_MAX;
-			if (posix_lock_file(&file->f_file, &lock, 0) < 0) {
+			if (posix_lock_file(&file->f_file, &lock) < 0) {
 				printk("lockd: unlock failure in %s:%d\n",
 						__FILE__, __LINE__);
 				return 1;

include/linux/fs.h

@@ -526,10 +526,10 @@ extern int init_private_file(struct file *, struct dentry *, int);
 
 #define FL_POSIX	1
 #define FL_FLOCK	2
-#define FL_BROKEN	4	/* broken flock() emulation */
-#define FL_ACCESS	8	/* for processes suspended by mandatory locking */
+#define FL_ACCESS	8	/* not trying to lock, just looking */
 #define FL_LOCKD	16	/* lock held by rpc.lockd */
 #define FL_LEASE	32	/* lease held on this file */
+#define FL_SLEEP	128	/* A blocking lock */
 
 /*
  * The POSIX file lock owner is determined by
@@ -591,9 +591,9 @@ extern void locks_copy_lock(struct file_lock *, struct file_lock *);
 extern void locks_remove_posix(struct file *, fl_owner_t);
 extern void locks_remove_flock(struct file *);
 extern struct file_lock *posix_test_lock(struct file *, struct file_lock *);
-extern int posix_lock_file(struct file *, struct file_lock *, unsigned int);
+extern int posix_lock_file(struct file *, struct file_lock *);
 extern void posix_block_lock(struct file_lock *, struct file_lock *);
-extern void posix_unblock_lock(struct file_lock *);
+extern void posix_unblock_lock(struct file *, struct file_lock *);
 extern int posix_locks_deadlock(struct file_lock *, struct file_lock *);
 extern int __get_lease(struct inode *inode, unsigned int flags);
 extern time_t lease_get_mtime(struct inode *);