[PATCH] xfs: improve xfs_isilocked

[Christoph Hellwig]

Use rwsem_is_locked to make the assertations for shared locks work.

Signed-off-by: Christoph Hellwig <hch at lst.de>

Index: xfs/fs/xfs/xfs_iget.c
===================================================================
--- xfs.orig/fs/xfs/xfs_iget.c	2010-05-25 11:40:59.216005587 +0200
+++ xfs/fs/xfs/xfs_iget.c	2010-05-27 20:59:09.244004330 +0200
@@ -740,30 +738,24 @@ xfs_ilock_demote(
 }
 
 #ifdef DEBUG
-/*
- * Debug-only routine, without additional rw_semaphore APIs, we can
- * now only answer requests regarding whether we hold the lock for write
- * (reader state is outside our visibility, we only track writer state).
- *
- * Note: this means !xfs_isilocked would give false positives, so don't do that.
- */
 int
 xfs_isilocked(
 	xfs_inode_t		*ip,
 	uint			lock_flags)
 {
-	if ((lock_flags & (XFS_ILOCK_EXCL|XFS_ILOCK_SHARED)) ==
-			XFS_ILOCK_EXCL) {
-		if (!ip->i_lock.mr_writer)
-			return 0;
+	if (lock_flags & (XFS_ILOCK_EXCL|XFS_ILOCK_SHARED)) {
+		if (!(lock_flags & XFS_ILOCK_SHARED))
+			return !!ip->i_lock.mr_writer;
+		return rwsem_is_locked(&ip->i_lock.mr_lock);
 	}
 
-	if ((lock_flags & (XFS_IOLOCK_EXCL|XFS_IOLOCK_SHARED)) ==
-			XFS_IOLOCK_EXCL) {
-		if (!ip->i_iolock.mr_writer)
-			return 0;
+	if (lock_flags & (XFS_IOLOCK_EXCL|XFS_IOLOCK_SHARED)) {
+		if (!(lock_flags & XFS_IOLOCK_SHARED))
+			return !!ip->i_iolock.mr_writer;
+		return rwsem_is_locked(&ip->i_iolock.mr_lock);
 	}
 
-	return 1;
+	ASSERT(0);
+	return 0;
 }
 #endif