From ce421581794f6593830b056969ad7536ab929b2f Mon Sep 17 00:00:00 2001
From: "Jose R. Santos" <jrs@us.ibm.com>
Date: Tue, 16 Oct 2007 18:38:25 -0400
Subject: [PATCH] ext4: FLEX_BG Kernel support v2.
This feature relaxes check restrictions on where each block groups meta
data is located within the storage media. This allows for the allocation
of bitmaps or inode tables outside the block group boundaries in cases
where bad blocks forces us to look for new blocks which the owning block
group can not satisfy. This will also allow for new meta-data allocation
schemes to improve performance and scalability.
Signed-off-by: Jose R. Santos <jrs@us.ibm.com>
Cc: <linux-ext4@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
fs/ext4/super.c | 9 +++++++--
include/linux/ext4_fs.h | 4 +++-
2 files changed, 10 insertions(+), 3 deletions(-)
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index dd4ff9c8735..54450fa1af3 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1358,13 +1358,17 @@ static int ext4_check_descriptors (struct super_block * sb)
ext4_fsblk_t inode_table;
struct ext4_group_desc * gdp = NULL;
int desc_block = 0;
+ int flexbg_flag = 0;
int i;
+ if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG))
+ flexbg_flag = 1;
+
ext4_debug ("Checking group descriptors");
for (i = 0; i < sbi->s_groups_count; i++)
{
- if (i == sbi->s_groups_count - 1)
+ if (i == sbi->s_groups_count - 1 || flexbg_flag)
last_block = ext4_blocks_count(sbi->s_es) - 1;
else
last_block = first_block +
@@ -1409,7 +1413,8 @@ static int ext4_check_descriptors (struct super_block * sb)
le16_to_cpu(gdp->bg_checksum));
return 0;
}
- first_block += EXT4_BLOCKS_PER_GROUP(sb);
+ if (!flexbg_flag)
+ first_block += EXT4_BLOCKS_PER_GROUP(sb);
gdp = (struct ext4_group_desc *)
((__u8 *)gdp + EXT4_DESC_SIZE(sb));
}
diff --git a/include/linux/ext4_fs.h b/include/linux/ext4_fs.h
index 722d4ef12bf..46b304d1834 100644
--- a/include/linux/ext4_fs.h
+++ b/include/linux/ext4_fs.h
@@ -682,13 +682,15 @@ static inline int ext4_valid_inum(struct super_block *sb, unsigned long ino)
#define EXT4_FEATURE_INCOMPAT_META_BG 0x0010
#define EXT4_FEATURE_INCOMPAT_EXTENTS 0x0040 /* extents support */
#define EXT4_FEATURE_INCOMPAT_64BIT 0x0080
+#define EXT4_FEATURE_INCOMPAT_FLEX_BG 0x0200
#define EXT4_FEATURE_COMPAT_SUPP EXT2_FEATURE_COMPAT_EXT_ATTR
#define EXT4_FEATURE_INCOMPAT_SUPP (EXT4_FEATURE_INCOMPAT_FILETYPE| \
EXT4_FEATURE_INCOMPAT_RECOVER| \
EXT4_FEATURE_INCOMPAT_META_BG| \
EXT4_FEATURE_INCOMPAT_EXTENTS| \
- EXT4_FEATURE_INCOMPAT_64BIT)
+ EXT4_FEATURE_INCOMPAT_64BIT| \
+ EXT4_FEATURE_INCOMPAT_FLEX_BG)
#define EXT4_FEATURE_RO_COMPAT_SUPP (EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER| \
EXT4_FEATURE_RO_COMPAT_LARGE_FILE| \
EXT4_FEATURE_RO_COMPAT_GDT_CSUM| \
--
2.41.3