From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Darrick J. Wong" Subject: [PATCH 4/5] ext4: don't crash when validating block bitmap Date: Thu, 01 May 2014 16:17:47 -0700 Message-ID: <20140501231747.892.95073.stgit@birch.djwong.org> References: <20140501231720.892.58712.stgit@birch.djwong.org> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Cc: linux-ext4@vger.kernel.org To: tytso@mit.edu, darrick.wong@oracle.com Return-path: Received: from userp1040.oracle.com ([156.151.31.81]:29579 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751014AbaEAXRv (ORCPT ); Thu, 1 May 2014 19:17:51 -0400 In-Reply-To: <20140501231720.892.58712.stgit@birch.djwong.org> Sender: linux-ext4-owner@vger.kernel.org List-ID: If EXT4FS_DEBUG is defined, ext4_validate_block_bitmap is called via ext4_count_free_clusters before sb->s_group_info is set up. When this happens, the kernel crashes because group info hasn't been loaded. Forego marking the group corrupt for now; not setting BH_Verified means we'll revisit the bitmap if something went wrong. Signed-off-by: Darrick J. Wong --- fs/ext4/balloc.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c index 59c3ba8..8f7bed0 100644 --- a/fs/ext4/balloc.c +++ b/fs/ext4/balloc.c @@ -357,7 +357,10 @@ void ext4_validate_block_bitmap(struct super_block *sb, struct buffer_head *bh) { ext4_fsblk_t blk; - struct ext4_group_info *grp = ext4_get_group_info(sb, block_group); + struct ext4_group_info *grp = NULL; + + if (EXT4_SB(sb)->s_group_info) + grp = ext4_get_group_info(sb, block_group); if (buffer_verified(bh)) return; @@ -368,14 +371,18 @@ void ext4_validate_block_bitmap(struct super_block *sb, ext4_unlock_group(sb, block_group); ext4_error(sb, "bg %u: block %llu: invalid block bitmap", block_group, blk); - set_bit(EXT4_GROUP_INFO_BBITMAP_CORRUPT_BIT, &grp->bb_state); + if (grp) + set_bit(EXT4_GROUP_INFO_BBITMAP_CORRUPT_BIT, + &grp->bb_state); return; } if (unlikely(!ext4_block_bitmap_csum_verify(sb, block_group, desc, bh))) { ext4_unlock_group(sb, block_group); ext4_error(sb, "bg %u: bad block bitmap checksum", block_group); - set_bit(EXT4_GROUP_INFO_BBITMAP_CORRUPT_BIT, &grp->bb_state); + if (grp) + set_bit(EXT4_GROUP_INFO_BBITMAP_CORRUPT_BIT, + &grp->bb_state); return; } set_buffer_verified(bh);