linux-ext4 - [PATCH] libext2fs: fix maximum bg overhead calculation with meta_bg enabled in ext2fs

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Message-ID: <20150919052635.GG10390@birch.djwong.org>
Date:	Fri, 18 Sep 2015 22:26:35 -0700
From:	"Darrick J. Wong" <darrick.wong@...cle.com>
To:	tytso@....edu
Cc:	linux-ext4@...r.kernel.org, Dave Chinner <david@...morbit.com>
Subject: [PATCH] libext2fs: fix maximum bg overhead calculation with meta_bg
 enabled in ext2fs_initialize

When meta_bg is enabled at mkfs time, we put at most one group
descriptor block in each blockgroup.  Unfortunately, the calculation
of max overhead per bg doesn't know this, so mkfs fails when it isn't
strictly necessary.  Fix it, since Dave reported that he couldn't
create a 500TB ext4 filesystem.

Reported-by: Dave Chinner <david@...morbit.com>
Signed-off-by: Darrick J. Wong <darrick.wong@...cle.com>
---
 lib/ext2fs/initialize.c |    7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/lib/ext2fs/initialize.c b/lib/ext2fs/initialize.c
index 75fbf8e..f672a27 100644
--- a/lib/ext2fs/initialize.c
+++ b/lib/ext2fs/initialize.c
@@ -379,7 +379,12 @@ ipg_retry:
 	 * table, and the reserved gdt blocks.
 	 */
 	overhead = (int) (3 + fs->inode_blocks_per_group +
-			  fs->desc_blocks + super->s_reserved_gdt_blocks);
+			  super->s_reserved_gdt_blocks);
+
+	if (fs->super->s_feature_incompat & EXT2_FEATURE_INCOMPAT_META_BG)
+		overhead++;
+	else
+		overhead += fs->desc_blocks;

 	/* This can only happen if the user requested too many inodes */
 	if (overhead > super->s_blocks_per_group) {
--
To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html