Re: 64KB "boot sector" gap

2012-12-03 Thread Zach Brown
On Mon, Dec 03, 2012 at 12:34:06AM -0700, Chris Murphy wrote: > When creating a btrfs volume with mkfs.btrfs, I'm noticing that the > first 64KB are completely blank. Is this gap expressly intended for > installing a boot manager/loader? If you want some historical reading check out the 'BTRFS par

Re: 64KB "boot sector" gap

2012-12-03 Thread Chris Mason
On Mon, Dec 03, 2012 at 12:34:06AM -0700, Chris Murphy wrote: > When creating a btrfs volume with mkfs.btrfs, I'm noticing that the > first 64KB are completely blank. Is this gap expressly intended for > installing a boot manager/loader? e.g. GRUB 2 allows installation of > boot.img + core.img into

Re: 64KB "boot sector" gap

2012-12-02 Thread Chris Murphy
No idea what that means. On Dec 3, 2012, at 12:52 AM, Rock Lee wrote: > Maybe this function could give you a little explanation. > > static inline u64 btrfs_sb_offset(int mirror) > { >u64 start = 16 * 1024; >if (mirror) >return start << (BTRFS_SUPER_MIRROR_SHIFT * mirror); >

Re: 64KB "boot sector" gap

2012-12-02 Thread Rock Lee
Maybe this function could give you a little explanation. static inline u64 btrfs_sb_offset(int mirror) { u64 start = 16 * 1024; if (mirror) return start << (BTRFS_SUPER_MIRROR_SHIFT * mirror); return BTRFS_SUPER_INFO_OFFSET; } and BTRFS_SUPER_INFO_OFFSET is (64 * 1024) 2012/

64KB "boot sector" gap

2012-12-02 Thread Chris Murphy
When creating a btrfs volume with mkfs.btrfs, I'm noticing that the first 64KB are completely blank. Is this gap expressly intended for installing a boot manager/loader? e.g. GRUB 2 allows installation of boot.img + core.img into a btrfs formatted partition, without using block lists (the --forc