xfs: return the buffer locked from xfs_buf_get_uncached

All other xfs_buf_get/read-like helpers return the buffer locked, make sure
xfs_buf_get_uncached isn't different for no reason.  Half of the callers
already lock it directly after, and the others probably should also keep
it locked if only for consistency and beeing able to use xfs_buf_rele,
but I'll leave that for later.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Alex Elder <aelder@sgi.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

fs/xfs/linux-2.6/xfs_buf.c

@@ -679,7 +679,6 @@ xfs_buf_read_uncached(
 		return NULL;
 
 	/* set up the buffer for a read IO */
-	xfs_buf_lock(bp);
 	XFS_BUF_SET_ADDR(bp, daddr);
 	XFS_BUF_READ(bp);
 	XFS_BUF_BUSY(bp);
@@ -814,8 +813,6 @@ xfs_buf_get_uncached(
 		goto fail_free_mem;
 	}
 
-	xfs_buf_unlock(bp);
-
 	trace_xfs_buf_get_uncached(bp, _RET_IP_);
 	return bp;
 

fs/xfs/xfs_log.c

@@ -1090,8 +1090,7 @@ xlog_alloc_log(xfs_mount_t	*mp,
 						log->l_iclog_size, 0);
 		if (!bp)
 			goto out_free_iclog;
-		if (!xfs_buf_trylock(bp))
-			ASSERT(0);
+
 		XFS_BUF_SET_IODONE_FUNC(bp, xlog_iodone);
 		XFS_BUF_SET_FSPRIVATE2(bp, (unsigned long)1);
 		iclog->ic_bp = bp;

fs/xfs/xfs_log_recover.c

@@ -91,6 +91,8 @@ xlog_get_bp(
 	xlog_t		*log,
 	int		nbblks)
 {
+	struct xfs_buf	*bp;
+
 	if (!xlog_buf_bbcount_valid(log, nbblks)) {
 		xfs_warn(log->l_mp, "Invalid block length (0x%x) for buffer",
 			nbblks);
@@ -118,8 +120,10 @@ xlog_get_bp(
 		nbblks += log->l_sectBBsize;
 	nbblks = round_up(nbblks, log->l_sectBBsize);
 
-	return xfs_buf_get_uncached(log->l_mp->m_logdev_targp,
-					BBTOB(nbblks), 0);
+	bp = xfs_buf_get_uncached(log->l_mp->m_logdev_targp, BBTOB(nbblks), 0);
+	if (bp)
+		xfs_buf_unlock(bp);
+	return bp;
 }
 
 STATIC void

fs/xfs/xfs_vnodeops.c

@@ -1969,6 +1969,8 @@ xfs_zero_remaining_bytes(
 	if (!bp)
 		return XFS_ERROR(ENOMEM);
 
+	xfs_buf_unlock(bp);
+
 	for (offset = startoff; offset <= endoff; offset = lastoffset + 1) {
 		offset_fsb = XFS_B_TO_FSBT(mp, offset);
 		nimap = 1;