Re: Initial results of FLEX_BG feature.

["Jose R. Santos" <jrs@us.ibm.com>]

On Wed, 11 Jul 2007 18:14:25 -0400
Theodore Tso <tytso@mit.edu> wrote:

> On Wed, Jul 11, 2007 at 12:30:04AM -0500, Jose R. Santos wrote:
> > Right now what I've done is allocate the bitmaps and inode tables at the
> > beginning of each group of 64 BG.  Still need to work on fsck since just
> > removing the restriction on were the bitmaps and inode table are
> > located still gives me errors of uninitialized inodes with dtime set.
> > Seems like fsck still expect inode information to be located at
> > specific locations within the disk.
> 
> Can you send me the patch which you were playing with?  I might be
> able to help you with this.  It should be pretty straightforward to
> remove the constraint on the inode table location.  

Here is the kernel piece.

-JRS

---
 fs/ext4/super.c         |    3 	3 +	0 -	0 !
 include/linux/ext4_fs.h |    4 	3 +	1 -	0 !
 2 files changed, 6 insertions(+), 1 deletion(-)

Index: linux-2.6/fs/ext4/super.c
===================================================================
--- linux-2.6.orig/fs/ext4/super.c	2007-07-11 15:34:58.000000000 -0500
+++ linux-2.6/fs/ext4/super.c	2007-07-11 16:19:08.000000000 -0500
@@ -1271,6 +1271,9 @@ static int ext4_check_descriptors (struc
 
 	ext4_debug ("Checking group descriptors");
 
+	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG))
+		return 1;
+
 	for (i = 0; i < sbi->s_groups_count; i++)
 	{
 		if (i == sbi->s_groups_count - 1)
Index: linux-2.6/include/linux/ext4_fs.h
===================================================================
--- linux-2.6.orig/include/linux/ext4_fs.h	2007-07-11 15:34:58.000000000 -0500
+++ linux-2.6/include/linux/ext4_fs.h	2007-07-12 09:58:51.000000000 -0500
@@ -698,13 +698,15 @@ static inline int ext4_valid_inum(struct
 #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_DIR_NLINK | \