Re: BTRFS partition usage...

2008-02-13 Thread Szabolcs Szakacsits
On Tue, 12 Feb 2008, Jeff Garzik wrote: > > Yep. I chose 32K unused space in the prototype filesystem I wrote [1, 2.4 > era]. I'm pretty sure I got that number from some other filesystem, maybe > even some NTFS incarnation. NTFS superblock (and the partial mirror copy) can be anywhere

Re: BTRFS partition usage...

2008-02-13 Thread Szabolcs Szakacsits
On Tue, 12 Feb 2008, Jeff Garzik wrote: Yep. I chose 32K unused space in the prototype filesystem I wrote [1, 2.4 era]. I'm pretty sure I got that number from some other filesystem, maybe even some NTFS incarnation. NTFS superblock (and the partial mirror copy) can be anywhere except in

Re: BTRFS partition usage...

2008-02-12 Thread Christoph Hellwig
On Tue, Feb 12, 2008 at 03:35:57PM -0800, David Miller wrote: > What XFS does is really unfortunate, let's learn from it's > mistake. I'd rather say what Sun did with their disklabels was rather unfortunate :) But yeah, new filesystem should cater for it's braindamage because it doesn't have any

Re: BTRFS partition usage...

2008-02-12 Thread Jeff Garzik
David Miller wrote: From: Chris Mason <[EMAIL PROTECTED]> Date: Tue, 12 Feb 2008 09:08:59 -0500 I've had requests to move the super down to 64k to make room for bootloaders, which may not matter for sparc, but I don't really plan on different locations for different arches. The Sun disk

Re: BTRFS partition usage...

2008-02-12 Thread Bryan Henderson
> The Sun disk label only allows you to specify the start of a partition > in cylinders, so if you want to use a filesystem like XFS you have to > start the partition on cylinder 1 which can be many blocks into the > disk. That entire first cylinder is completely wasted. I don't believe a

Re: BTRFS partition usage...

2008-02-12 Thread Rene Herman
On 13-02-08 00:42, Jan Engelhardt wrote: x86 MSDOS partition table layout starts counting with sector 1, which is (not so intuitively) starting at 0x7e00 (and there's no sector 0, probably for safety). Well, each ptable format with its own quirks. I haven't followed this thread, but in case

Re: BTRFS partition usage...

2008-02-12 Thread David Miller
From: Jan Engelhardt <[EMAIL PROTECTED]> Date: Wed, 13 Feb 2008 00:42:56 +0100 (CET) > > On Feb 12 2008 15:38, David Miller wrote: > > > >> I still don't like the idea of btrfs trying to be smarter than a user > >> who can partition up his system according to > >>(a) his likes > >>(b)

Re: BTRFS partition usage...

2008-02-12 Thread David Miller
From: Jan Engelhardt <[EMAIL PROTECTED]> Date: Wed, 13 Feb 2008 00:39:16 +0100 (CET) > On the other hand, the H and S of CHS could be lowered and S increased, > e.g. divide H by 2, divide S by 2, multiply S by 4. This gives a finer > bytes/cylinder granularity. That's really not an option when

Re: BTRFS partition usage...

2008-02-12 Thread Theodore Tso
On Tue, Feb 12, 2008 at 03:28:26PM -0800, David Miller wrote: > From: Jan Engelhardt <[EMAIL PROTECTED]> > Date: Tue, 12 Feb 2008 15:00:20 +0100 (CET) > > > Something looks wrong here. Why would btrfs need to zero at all? > > So that existing superblocks on the partition won't > be interpreted

Re: BTRFS partition usage...

2008-02-12 Thread Jan Engelhardt
On Feb 12 2008 15:38, David Miller wrote: > >> I still don't like the idea of btrfs trying to be smarter than a user >> who can partition up his system according to >> (a) his likes >> (b) system or hardware requirements or recommendations >> to align the superblock to a specific

Re: BTRFS partition usage...

2008-02-12 Thread Jan Engelhardt
On Feb 12 2008 15:26, David Miller wrote: > >> (Yes, I had xfs on sparc before, so it's not like you NEED the >> whitespace at the start of a partition.) > >You actully do unless you want to lose significant chunks of your disk >space. > >The Sun disk label only allows you to specify the start

Re: BTRFS partition usage...

2008-02-12 Thread David Miller
From: Jan Engelhardt <[EMAIL PROTECTED]> Date: Tue, 12 Feb 2008 16:04:52 +0100 (CET) > I still don't like the idea of btrfs trying to be smarter than a user > who can partition up his system according to > (a) his likes > (b) system or hardware requirements or recommendations > to

Re: BTRFS partition usage...

2008-02-12 Thread David Miller
From: Chris Mason <[EMAIL PROTECTED]> Date: Tue, 12 Feb 2008 09:35:20 -0500 > From my point of view, 0 is a bad idea because it is very likely to > conflict with other things. Starting at 0 is a bad idea because otherwise you'll waste significant chunks of your disk on Sparc because of reasons

Re: BTRFS partition usage...

2008-02-12 Thread David Miller
From: Jan Engelhardt <[EMAIL PROTECTED]> Date: Tue, 12 Feb 2008 15:21:52 +0100 (CET) > For sparc you could have something like > > startlbaendlba type > sda10 2 1 Boot > sda22 58 3 Whole

Re: BTRFS partition usage...

2008-02-12 Thread David Miller
From: Chris Mason <[EMAIL PROTECTED]> Date: Tue, 12 Feb 2008 09:08:59 -0500 > I've had requests to move the super down to 64k to make room for > bootloaders, which may not matter for sparc, but I don't really plan > on different locations for different arches. The Sun disk label sits in the

Re: BTRFS partition usage...

2008-02-12 Thread David Miller
From: Jan Engelhardt <[EMAIL PROTECTED]> Date: Tue, 12 Feb 2008 15:00:20 +0100 (CET) > Something looks wrong here. Why would btrfs need to zero at all? So that existing superblocks on the partition won't be interpreted as correct by other filesystems. It's a safety measure many mkfs programs

Re: BTRFS partition usage...

2008-02-12 Thread David Miller
From: Jan Engelhardt <[EMAIL PROTECTED]> Date: Tue, 12 Feb 2008 15:00:20 +0100 (CET) > (Yes, I had xfs on sparc before, so it's not like you NEED the > whitespace at the start of a partition.) You actully do unless you want to lose significant chunks of your disk space. The Sun disk label only

Re: BTRFS partition usage...

2008-02-12 Thread David Miller
From: Chris Mason <[EMAIL PROTECTED]> Date: Tue, 12 Feb 2008 08:49:34 -0500 > So, if Btrfs starts zeroing at 1k, will that be acceptable for you? Sure. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at

Re: BTRFS partition usage...

2008-02-12 Thread Chris Mason
On Tuesday 12 February 2008, Jan Engelhardt wrote: > On Feb 12 2008 09:35, Chris Mason wrote: > >> and slap the bootloader into "MBR", just like on x86. > >> Or I am missing something.. > > > >It was a request from hpa, and he clearly had something in mind. He > > kindly offered to review the

Re: BTRFS partition usage...

2008-02-12 Thread Jan Engelhardt
> On Feb 12 2008 09:35, Chris Mason wrote: >> >> and slap the bootloader into "MBR", just like on x86. >> Or I am missing something.. > >It was a request from hpa, and he clearly had something in mind. He kindly >offered to review the disk format for bootloaders and other lower level >issues

Re: BTRFS partition usage...

2008-02-12 Thread Chris Mason
On Tuesday 12 February 2008, Jan Engelhardt wrote: > On Feb 12 2008 09:08, Chris Mason wrote: > >> >So, if Btrfs starts zeroing at 1k, will that be acceptable for you? > >> > >> Something looks wrong here. Why would btrfs need to zero at all? > >> Superblock at 0, and done. Just like xfs. > >>

Re: BTRFS partition usage...

2008-02-12 Thread Jan Engelhardt
On Feb 12 2008 09:08, Chris Mason wrote: >> > >> >So, if Btrfs starts zeroing at 1k, will that be acceptable for you? >> >> Something looks wrong here. Why would btrfs need to zero at all? >> Superblock at 0, and done. Just like xfs. >> (Yes, I had xfs on sparc before, so it's not like you NEED

Re: BTRFS partition usage...

2008-02-12 Thread Chris Mason
On Tuesday 12 February 2008, Jan Engelhardt wrote: > On Feb 12 2008 08:49, Chris Mason wrote: > >> > This is a real issue on sparc where the default sun disk labels > >> > created use an initial partition where block zero aliases the disk > >> > label. It took me a few iterations before I figured

Re: BTRFS partition usage...

2008-02-12 Thread Jan Engelhardt
On Feb 12 2008 08:49, Chris Mason wrote: >> > >> > This is a real issue on sparc where the default sun disk labels >> > created use an initial partition where block zero aliases the disk >> > label. It took me a few iterations before I figured out why every >> > btrfs make would zero out my disk

Re: BTRFS partition usage...

2008-02-12 Thread Chris Mason
On Tuesday 12 February 2008, David Miller wrote: > From: David Miller <[EMAIL PROTECTED]> > Date: Mon, 11 Feb 2008 23:21:39 -0800 (PST) > > > Filesystems like ext2 put their superblock 1 block into the partition > > in order to avoid overwriting disk labels and other uglies. UFS does > > this

Re: BTRFS partition usage...

2008-02-12 Thread David Miller
From: David Miller <[EMAIL PROTECTED]> Date: Mon, 11 Feb 2008 23:21:39 -0800 (PST) > Filesystems like ext2 put their superblock 1 block into the partition > in order to avoid overwriting disk labels and other uglies. UFS does > this too, as do several others. One of the few exceptions I've been

Re: BTRFS partition usage...

2008-02-12 Thread David Miller
From: David Miller [EMAIL PROTECTED] Date: Mon, 11 Feb 2008 23:21:39 -0800 (PST) Filesystems like ext2 put their superblock 1 block into the partition in order to avoid overwriting disk labels and other uglies. UFS does this too, as do several others. One of the few exceptions I've been

Re: BTRFS partition usage...

2008-02-12 Thread David Miller
From: Chris Mason [EMAIL PROTECTED] Date: Tue, 12 Feb 2008 08:49:34 -0500 So, if Btrfs starts zeroing at 1k, will that be acceptable for you? Sure. -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at

Re: BTRFS partition usage...

2008-02-12 Thread Jan Engelhardt
On Feb 12 2008 15:26, David Miller wrote: (Yes, I had xfs on sparc before, so it's not like you NEED the whitespace at the start of a partition.) You actully do unless you want to lose significant chunks of your disk space. The Sun disk label only allows you to specify the start of a

Re: BTRFS partition usage...

2008-02-12 Thread David Miller
From: Jan Engelhardt [EMAIL PROTECTED] Date: Tue, 12 Feb 2008 16:04:52 +0100 (CET) I still don't like the idea of btrfs trying to be smarter than a user who can partition up his system according to (a) his likes (b) system or hardware requirements or recommendations to align the

Re: BTRFS partition usage...

2008-02-12 Thread Theodore Tso
On Tue, Feb 12, 2008 at 03:28:26PM -0800, David Miller wrote: From: Jan Engelhardt [EMAIL PROTECTED] Date: Tue, 12 Feb 2008 15:00:20 +0100 (CET) Something looks wrong here. Why would btrfs need to zero at all? So that existing superblocks on the partition won't be interpreted as correct

Re: BTRFS partition usage...

2008-02-12 Thread Bryan Henderson
The Sun disk label only allows you to specify the start of a partition in cylinders, so if you want to use a filesystem like XFS you have to start the partition on cylinder 1 which can be many blocks into the disk. That entire first cylinder is completely wasted. I don't believe a cylinder

Re: BTRFS partition usage...

2008-02-12 Thread David Miller
From: Jan Engelhardt [EMAIL PROTECTED] Date: Wed, 13 Feb 2008 00:42:56 +0100 (CET) On Feb 12 2008 15:38, David Miller wrote: I still don't like the idea of btrfs trying to be smarter than a user who can partition up his system according to (a) his likes (b) system or hardware

Re: BTRFS partition usage...

2008-02-12 Thread David Miller
From: Jan Engelhardt [EMAIL PROTECTED] Date: Tue, 12 Feb 2008 15:21:52 +0100 (CET) For sparc you could have something like startlbaendlba type sda10 2 1 Boot sda22 58 3 Whole disk

Re: BTRFS partition usage...

2008-02-12 Thread Rene Herman
On 13-02-08 00:42, Jan Engelhardt wrote: x86 MSDOS partition table layout starts counting with sector 1, which is (not so intuitively) starting at 0x7e00 (and there's no sector 0, probably for safety). Well, each ptable format with its own quirks. I haven't followed this thread, but in case

Re: BTRFS partition usage...

2008-02-12 Thread Jeff Garzik
David Miller wrote: From: Chris Mason [EMAIL PROTECTED] Date: Tue, 12 Feb 2008 09:08:59 -0500 I've had requests to move the super down to 64k to make room for bootloaders, which may not matter for sparc, but I don't really plan on different locations for different arches. The Sun disk label

Re: BTRFS partition usage...

2008-02-12 Thread Jan Engelhardt
On Feb 12 2008 15:38, David Miller wrote: I still don't like the idea of btrfs trying to be smarter than a user who can partition up his system according to (a) his likes (b) system or hardware requirements or recommendations to align the superblock to a specific location. All of

Re: BTRFS partition usage...

2008-02-12 Thread David Miller
From: Chris Mason [EMAIL PROTECTED] Date: Tue, 12 Feb 2008 09:35:20 -0500 From my point of view, 0 is a bad idea because it is very likely to conflict with other things. Starting at 0 is a bad idea because otherwise you'll waste significant chunks of your disk on Sparc because of reasons I've

Re: BTRFS partition usage...

2008-02-12 Thread David Miller
From: Jan Engelhardt [EMAIL PROTECTED] Date: Tue, 12 Feb 2008 15:00:20 +0100 (CET) Something looks wrong here. Why would btrfs need to zero at all? So that existing superblocks on the partition won't be interpreted as correct by other filesystems. It's a safety measure many mkfs programs use.

Re: BTRFS partition usage...

2008-02-12 Thread David Miller
From: Jan Engelhardt [EMAIL PROTECTED] Date: Tue, 12 Feb 2008 15:00:20 +0100 (CET) (Yes, I had xfs on sparc before, so it's not like you NEED the whitespace at the start of a partition.) You actully do unless you want to lose significant chunks of your disk space. The Sun disk label only

Re: BTRFS partition usage...

2008-02-12 Thread David Miller
From: Chris Mason [EMAIL PROTECTED] Date: Tue, 12 Feb 2008 09:08:59 -0500 I've had requests to move the super down to 64k to make room for bootloaders, which may not matter for sparc, but I don't really plan on different locations for different arches. The Sun disk label sits in the first 512

Re: BTRFS partition usage...

2008-02-12 Thread David Miller
From: Jan Engelhardt [EMAIL PROTECTED] Date: Wed, 13 Feb 2008 00:39:16 +0100 (CET) On the other hand, the H and S of CHS could be lowered and S increased, e.g. divide H by 2, divide S by 2, multiply S by 4. This gives a finer bytes/cylinder granularity. That's really not an option when you

Re: BTRFS partition usage...

2008-02-12 Thread Chris Mason
On Tuesday 12 February 2008, Jan Engelhardt wrote: On Feb 12 2008 09:08, Chris Mason wrote: So, if Btrfs starts zeroing at 1k, will that be acceptable for you? Something looks wrong here. Why would btrfs need to zero at all? Superblock at 0, and done. Just like xfs. (Yes, I had xfs on

Re: BTRFS partition usage...

2008-02-12 Thread Chris Mason
On Tuesday 12 February 2008, Jan Engelhardt wrote: On Feb 12 2008 08:49, Chris Mason wrote: This is a real issue on sparc where the default sun disk labels created use an initial partition where block zero aliases the disk label. It took me a few iterations before I figured out why

Re: BTRFS partition usage...

2008-02-12 Thread Chris Mason
On Tuesday 12 February 2008, Jan Engelhardt wrote: On Feb 12 2008 09:35, Chris Mason wrote: and slap the bootloader into MBR, just like on x86. Or I am missing something.. It was a request from hpa, and he clearly had something in mind. He kindly offered to review the disk format for

Re: BTRFS partition usage...

2008-02-12 Thread Christoph Hellwig
On Tue, Feb 12, 2008 at 03:35:57PM -0800, David Miller wrote: What XFS does is really unfortunate, let's learn from it's mistake. I'd rather say what Sun did with their disklabels was rather unfortunate :) But yeah, new filesystem should cater for it's braindamage because it doesn't have any

Re: BTRFS partition usage...

2008-02-12 Thread Jan Engelhardt
On Feb 12 2008 09:35, Chris Mason wrote: and slap the bootloader into MBR, just like on x86. Or I am missing something.. It was a request from hpa, and he clearly had something in mind. He kindly offered to review the disk format for bootloaders and other lower level issues but I asked him

Re: BTRFS partition usage...

2008-02-12 Thread Jan Engelhardt
On Feb 12 2008 09:08, Chris Mason wrote: So, if Btrfs starts zeroing at 1k, will that be acceptable for you? Something looks wrong here. Why would btrfs need to zero at all? Superblock at 0, and done. Just like xfs. (Yes, I had xfs on sparc before, so it's not like you NEED the whitespace

Re: BTRFS partition usage...

2008-02-12 Thread Jan Engelhardt
On Feb 12 2008 08:49, Chris Mason wrote: This is a real issue on sparc where the default sun disk labels created use an initial partition where block zero aliases the disk label. It took me a few iterations before I figured out why every btrfs make would zero out my disk label :-/

BTRFS partition usage...

2008-02-11 Thread David Miller
Filesystems like ext2 put their superblock 1 block into the partition in order to avoid overwriting disk labels and other uglies. UFS does this too, as do several others. One of the few exceptions I've been able to find is XFS. This is a real issue on sparc where the default sun disk labels

BTRFS partition usage...

2008-02-11 Thread David Miller
Filesystems like ext2 put their superblock 1 block into the partition in order to avoid overwriting disk labels and other uglies. UFS does this too, as do several others. One of the few exceptions I've been able to find is XFS. This is a real issue on sparc where the default sun disk labels