From 8cef107a1d890ff76c85d665083ff3562be01d32 Mon Sep 17 00:00:00 2001
From: Frans van de Wiel <fvdw@fvdw.eu>
Date: Mon, 15 Mar 2010 19:29:34 +0100
Subject: ext3: Avoid loading bitmaps for full groups during block allocation

There is no point in loading bitmap for groups which are completely full.
This causes noticeable performance problems (and memory pressure) on small
systems with large full filesystem
(http://marc.info/?l=linux-ext4&m=126843108314310&w=2).

Jan Kara: Added a comment and changed check to use cpu-endian value.

Signed-off-by: "Frans van de Wiel" <fvdw@fvdw.eu>
Signed-off-by: Jan Kara <jack@suse.cz>

diff --git a/fs/ext3/balloc.c b/fs/ext3/balloc.c
index a177122..4a32511 100644
--- a/fs/ext3/balloc.c
+++ b/fs/ext3/balloc.c
@@ -1584,6 +1584,12 @@ retry_alloc:
 			goto io_error;
 		free_blocks = le16_to_cpu(gdp->bg_free_blocks_count);
 		/*
+		 * skip this group (and avoid loading bitmap) if there
+		 * are no free blocks
+		 */
+		if (!free_blocks)
+			continue;
+		/*
 		 * skip this group if the number of
 		 * free blocks is less than half of the reservation
 		 * window size.
-- 
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