From: NeilBrown As this is used to flag an internal bitmap. Also, introduce symbolic names for feature bits. Signed-off-by: Neil Brown Signed-off-by: Andrew Morton --- drivers/md/md.c | 6 +++--- include/linux/raid/md_p.h | 5 +++++ 2 files changed, 8 insertions(+), 3 deletions(-) diff -puN drivers/md/md.c~md-allow-md-to-load-a-superblock-with-feature-bit-1-set drivers/md/md.c --- devel/drivers/md/md.c~md-allow-md-to-load-a-superblock-with-feature-bit-1-set 2005-08-21 23:49:50.000000000 -0700 +++ devel-akpm/drivers/md/md.c 2005-08-21 23:49:50.000000000 -0700 @@ -875,7 +875,7 @@ static int super_1_load(mdk_rdev_t *rdev sb->major_version != cpu_to_le32(1) || le32_to_cpu(sb->max_dev) > (4096-256)/2 || le64_to_cpu(sb->super_offset) != (rdev->sb_offset<<1) || - sb->feature_map != 0) + (le32_to_cpu(sb->feature_map) & ~MD_FEATURE_ALL) != 0) return -EINVAL; if (calc_sb_1_csum(sb) != sb->sb_csum) { @@ -954,7 +954,7 @@ static int super_1_validate(mddev_t *mdd mddev->max_disks = (4096-256)/2; - if ((le32_to_cpu(sb->feature_map) & 1) && + if ((le32_to_cpu(sb->feature_map) & MD_FEATURE_BITMAP_OFFSET) && mddev->bitmap_file == NULL ) { if (mddev->level != 1) { printk(KERN_WARNING "md: bitmaps only supported for raid1\n"); @@ -1029,7 +1029,7 @@ static void super_1_sync(mddev_t *mddev, if (mddev->bitmap && mddev->bitmap_file == NULL) { sb->bitmap_offset = cpu_to_le32((__u32)mddev->bitmap_offset); - sb->feature_map = cpu_to_le32(1); + sb->feature_map = cpu_to_le32(MD_FEATURE_BITMAP_OFFSET); } max_dev = 0; diff -puN include/linux/raid/md_p.h~md-allow-md-to-load-a-superblock-with-feature-bit-1-set include/linux/raid/md_p.h --- devel/include/linux/raid/md_p.h~md-allow-md-to-load-a-superblock-with-feature-bit-1-set 2005-08-21 23:49:50.000000000 -0700 +++ devel-akpm/include/linux/raid/md_p.h 2005-08-21 23:49:50.000000000 -0700 @@ -238,5 +238,10 @@ struct mdp_superblock_1 { __u16 dev_roles[0]; /* role in array, or 0xffff for a spare, or 0xfffe for faulty */ }; +/* feature_map bits */ +#define MD_FEATURE_BITMAP_OFFSET 1 + +#define MD_FEATURE_ALL 1 + #endif _