From: Darrick J. Wong Date: Mon, 12 May 2014 14:06:27 +0000 (-0400) Subject: ext4: find the group descriptors on a 1k-block bigalloc,meta_bg filesystem X-Git-Tag: v3.16-rc1~79^2~14 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=bd63f6b0cd577e94846869db0c86a7b2bee79b26;p=platform%2Fkernel%2Flinux-exynos.git ext4: find the group descriptors on a 1k-block bigalloc,meta_bg filesystem On a filesystem with a 1k block size, the group descriptors live in block 2, not block 1. If the filesystem has bigalloc,meta_bg set, however, the calculation of the group descriptor table location does not take this into account and returns the wrong block number. Fix the calculation to return the correct value for this case. Signed-off-by: Darrick J. Wong Signed-off-by: "Theodore Ts'o" --- diff --git a/fs/ext4/super.c b/fs/ext4/super.c index 1f8cb18..e38dd7d 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -2405,6 +2405,16 @@ static ext4_fsblk_t descriptor_loc(struct super_block *sb, if (ext4_bg_has_super(sb, bg)) has_super = 1; + /* + * If we have a meta_bg fs with 1k blocks, group 0's GDT is at + * block 2, not 1. If s_first_data_block == 0 (bigalloc is enabled + * on modern mke2fs or blksize > 1k on older mke2fs) then we must + * compensate. + */ + if (sb->s_blocksize == 1024 && nr == 0 && + le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block) == 0) + has_super++; + return (has_super + ext4_group_first_block_no(sb, bg)); }