linux-ext4 - [PATCH RESEND] ext4: Fix kernel BUG at fs/ext4/mballoc.c:910!

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Message-Id: <1203006909.8970.20.camel@ext1.frec.bull.fr>
Date:	Thu, 14 Feb 2008 17:35:09 +0100
From:	Valerie Clement <valerie.clement@...l.net>
To:	linux-ext4 <linux-ext4@...r.kernel.org>
Cc:	Andreas Dilger <adilger@....com>,
	Aneesh Kumar <aneesh.kumar@...ux.vnet.ibm.com>,
	Mingming Cao <cmm@...ibm.com>
Subject: [PATCH RESEND] ext4: Fix kernel BUG at fs/ext4/mballoc.c:910!

Fix kernel BUG at fs/ext4/mballoc.c:910!

From: Valerie Clement <valerie.clement@...l.net>

With the flex_bg feature enabled, a large file creation oopses the
kernel.
The BUG_ON is:
	BUG_ON(len >= EXT4_BLOCKS_PER_GROUP(sb));

As the allocation of the bitmaps and the inode table can be done
outside the block group with flex_bg, this allows to allocate up to
EXT4_BLOCKS_PER_GROUP blocks in a group.
Depending on the group size and the block size, extents might be 
larger than BLOCKS_PER_GROUP(); use EXT_INIT_MAX_LEN instead of 
BLOCKS_PER_GROUP().

This patch fixes the oops.

Signed-off-by: Valerie Clement <valerie.clement@...l.net>
---

 fs/ext4/mballoc.c |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletions(-)

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index b0f84b4..ccc33e9 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -34,6 +34,7 @@
 #include <linux/pagemap.h>
 #include <linux/seq_file.h>
 #include <linux/version.h>
+#include <linux/ext4_fs_extents.h>
 #include "group.h"
 
 /*
@@ -907,7 +908,9 @@ static void ext4_mb_mark_free_simple(struct super_block *sb,
 	unsigned short chunk;
 	unsigned short border;
 
-	BUG_ON(len >= EXT4_BLOCKS_PER_GROUP(sb));
+	BUG_ON(len > EXT4_HAS_INCOMPAT_FEATURE(sb,
+			EXT4_FEATURE_INCOMPAT_FLEX_BG) ? EXT_INIT_MAX_LEN :
+			EXT4_BLOCKS_PER_GROUP(sb));
 
 	border = 2 << sb->s_blocksize_bits;
 


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