From 4198ce4de86d2144ce127bba0d263a005926acf2 Mon Sep 17 00:00:00 2001 From: "Darrick J. Wong" Date: Sat, 24 Oct 2015 00:30:02 -0400 Subject: [PATCH 03/16] libext2fs: automatically enable meta_bg to avoid filling up BG 0 commit 03940aac5492879ef365b07e69105a98f4dbabf9 If during formatting we'd lose more than 75% a block group to group descriptors and other metadata, enable the meta_bg feature. This enables us to create >500T filesystems with default options. Signed-off-by: Darrick J. Wong Signed-off-by: Theodore Ts'o --- lib/ext2fs/initialize.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/lib/ext2fs/initialize.c b/lib/ext2fs/initialize.c index 3548c56c..0b8355d8 100644 --- a/lib/ext2fs/initialize.c +++ b/lib/ext2fs/initialize.c @@ -379,6 +379,11 @@ ipg_retry: overhead = (int) (3 + fs->inode_blocks_per_group + super->s_reserved_gdt_blocks); + /* Enable meta_bg if we'd lose more than 3/4 of a BG to GDT blocks. */ + if (super->s_reserved_gdt_blocks + fs->desc_blocks > + super->s_blocks_per_group * 3 / 4) + fs->super->s_feature_incompat |= EXT2_FEATURE_INCOMPAT_META_BG; + if (fs->super->s_feature_incompat & EXT2_FEATURE_INCOMPAT_META_BG) overhead++; else -- 2.20.1