Re: file handle in statx

2023-12-18 Thread Donald Buczek
Dear Kent, On 12/13/23 14:48, Donald Buczek wrote: > On 12/13/23 13:28, Kent Overstreet wrote: >> On Wed, Dec 13, 2023 at 08:37:57AM +0100, Donald Buczek wrote: >>> Probably not for the specific applications I mentioned (backup, mirror, >>> accounting). These are intended to run continuously,

Re: file handle in statx (was: Re: How to cope with subvolumes and snapshots on muti-user systems?)

2023-12-14 Thread Kent Overstreet
On Fri, Dec 15, 2023 at 09:47:47AM +1100, NeilBrown wrote: > On Wed, 13 Dec 2023, Christian Brauner wrote: > > On Wed, Dec 13, 2023 at 08:46:54AM +1100, NeilBrown wrote: > > > On Wed, 13 Dec 2023, Miklos Szeredi wrote: > > > > On Tue, 12 Dec 2023 at 16:35, Kent Overstreet > > > > wrote: > > > >

Re: file handle in statx (was: Re: How to cope with subvolumes and snapshots on muti-user systems?)

2023-12-14 Thread NeilBrown
On Wed, 13 Dec 2023, Christian Brauner wrote: > On Wed, Dec 13, 2023 at 08:46:54AM +1100, NeilBrown wrote: > > On Wed, 13 Dec 2023, Miklos Szeredi wrote: > > > On Tue, 12 Dec 2023 at 16:35, Kent Overstreet > > > wrote: > > > > > > > Other poeple have been finding ways to contribute to the

Re: file handle in statx (was: Re: How to cope with subvolumes and snapshots on muti-user systems?)

2023-12-13 Thread Kent Overstreet
On Wed, Dec 13, 2023 at 03:45:41PM -0700, Andreas Dilger wrote: > It should be possible for userspace and the kernel to increase the size of > struct statx independently, and not have any issues. If userspace requests > a field via STATX_* flags that the kernel doesn't understand, then it will >

Re: file handle in statx (was: Re: How to cope with subvolumes and snapshots on muti-user systems?)

2023-12-13 Thread Andreas Dilger
On Dec 12, 2023, at 5:02 PM, NeilBrown wrote: > > On Wed, 13 Dec 2023, Kent Overstreet wrote: >> On Wed, Dec 13, 2023 at 09:57:22AM +1100, NeilBrown wrote: >>> On Wed, 13 Dec 2023, Kent Overstreet wrote: On Mon, Dec 11, 2023 at 11:40:16PM +, David Howells wrote: > Kent Overstreet

Re: file handle in statx

2023-12-13 Thread Donald Buczek
On 12/13/23 13:28, Kent Overstreet wrote: > On Wed, Dec 13, 2023 at 08:37:57AM +0100, Donald Buczek wrote: >> Probably not for the specific applications I mentioned (backup, mirror, >> accounting). These are intended to run continuously, slowly and unnoticed >> in the background, so they are

Re: file handle in statx

2023-12-13 Thread Kent Overstreet
On Wed, Dec 13, 2023 at 08:37:57AM +0100, Donald Buczek wrote: > Probably not for the specific applications I mentioned (backup, mirror, > accounting). These are intended to run continuously, slowly and unnoticed > in the background, so they are memory and i/o throttled via cgroups anyway > and

Re: file handle in statx (was: Re: How to cope with subvolumes and snapshots on muti-user systems?)

2023-12-13 Thread Christian Brauner
On Wed, Dec 13, 2023 at 10:48:01AM +0100, Christian Brauner wrote: > On Wed, Dec 13, 2023 at 08:46:54AM +1100, NeilBrown wrote: > > On Wed, 13 Dec 2023, Miklos Szeredi wrote: > > > On Tue, 12 Dec 2023 at 16:35, Kent Overstreet > > > wrote: > > > > > > > Other poeple have been finding ways to

Re: file handle in statx (was: Re: How to cope with subvolumes and snapshots on muti-user systems?)

2023-12-13 Thread Christian Brauner
On Wed, Dec 13, 2023 at 08:46:54AM +1100, NeilBrown wrote: > On Wed, 13 Dec 2023, Miklos Szeredi wrote: > > On Tue, 12 Dec 2023 at 16:35, Kent Overstreet > > wrote: > > > > > Other poeple have been finding ways to contribute to the technical > > > discussion; just calling things "ugly and

Re: file handle in statx (was: Re: How to cope with subvolumes and snapshots on muti-user systems?)

2023-12-13 Thread Christian Brauner
> But when you show up to a discussion that's been going on for a page, On the bcachefs mailing list without fsdevel or anyone else Cced. > where everything's been constructively gathering input, and you start > namecalling - and crucially, _without giving any technical justification I didn't

Re: file handle in statx

2023-12-12 Thread Donald Buczek
On 12/12/23 16:20, Theodore Ts'o wrote: > On Tue, Dec 12, 2023 at 10:10:23AM +0100, Donald Buczek wrote: >> On 12/12/23 06:53, Dave Chinner wrote: >> >>> So can someone please explain to me why we need to try to re-invent >>> a generic filehandle concept in statx when we already have a >>> have

Re: file handle in statx (was: Re: How to cope with subvolumes and snapshots on muti-user systems?)

2023-12-12 Thread Kent Overstreet
On Wed, Dec 13, 2023 at 11:02:29AM +1100, NeilBrown wrote: > On Wed, 13 Dec 2023, Kent Overstreet wrote: > > On Wed, Dec 13, 2023 at 09:57:22AM +1100, NeilBrown wrote: > > > On Wed, 13 Dec 2023, Kent Overstreet wrote: > > > > On Mon, Dec 11, 2023 at 11:40:16PM +, David Howells wrote: > > > > >

Re: file handle in statx (was: Re: How to cope with subvolumes and snapshots on muti-user systems?)

2023-12-12 Thread NeilBrown
On Wed, 13 Dec 2023, Dave Chinner wrote: > On Wed, Dec 13, 2023 at 09:31:13AM +1100, NeilBrown wrote: > > On Wed, 13 Dec 2023, Dave Chinner wrote: > > > > > > What you are suggesting is that we now duplicate filehandle encoding > > > into every filesystem's statx() implementation. That's a bad >

Re: file handle in statx (was: Re: How to cope with subvolumes and snapshots on muti-user systems?)

2023-12-12 Thread NeilBrown
On Wed, 13 Dec 2023, Kent Overstreet wrote: > On Wed, Dec 13, 2023 at 09:57:22AM +1100, NeilBrown wrote: > > On Wed, 13 Dec 2023, Kent Overstreet wrote: > > > On Mon, Dec 11, 2023 at 11:40:16PM +, David Howells wrote: > > > > Kent Overstreet wrote: > > > > > > > > > I was chatting a bit with

Re: file handle in statx

2023-12-12 Thread Dave Chinner
On Tue, Dec 12, 2023 at 05:39:27PM -0500, Kent Overstreet wrote: > On Wed, Dec 13, 2023 at 09:23:18AM +1100, Dave Chinner wrote: > > On Wed, Dec 13, 2023 at 08:57:43AM +1100, NeilBrown wrote: > > > On Wed, 13 Dec 2023, Dave Chinner wrote: > > > > On Tue, Dec 12, 2023 at 09:15:29AM -0800, Frank

Re: file handle in statx (was: Re: How to cope with subvolumes and snapshots on muti-user systems?)

2023-12-12 Thread Kent Overstreet
On Wed, Dec 13, 2023 at 09:57:22AM +1100, NeilBrown wrote: > On Wed, 13 Dec 2023, Kent Overstreet wrote: > > On Mon, Dec 11, 2023 at 11:40:16PM +, David Howells wrote: > > > Kent Overstreet wrote: > > > > > > > I was chatting a bit with David Howells on IRC about this, and floated > > > >

Re: file handle in statx (was: Re: How to cope with subvolumes and snapshots on muti-user systems?)

2023-12-12 Thread Kent Overstreet
On Wed, Dec 13, 2023 at 10:06:37AM +1100, Dave Chinner wrote: > On Wed, Dec 13, 2023 at 09:31:13AM +1100, NeilBrown wrote: > > On Wed, 13 Dec 2023, Dave Chinner wrote: > > > > > > What you are suggesting is that we now duplicate filehandle encoding > > > into every filesystem's statx()

Re: file handle in statx (was: Re: How to cope with subvolumes and snapshots on muti-user systems?)

2023-12-12 Thread NeilBrown
On Wed, 13 Dec 2023, Kent Overstreet wrote: > On Mon, Dec 11, 2023 at 11:40:16PM +, David Howells wrote: > > Kent Overstreet wrote: > > > > > I was chatting a bit with David Howells on IRC about this, and floated > > > adding the file handle to statx. It looks like there's enough space > > >

Re: file handle in statx

2023-12-12 Thread NeilBrown
On Wed, 13 Dec 2023, Dave Chinner wrote: > On Wed, Dec 13, 2023 at 08:57:43AM +1100, NeilBrown wrote: > > On Wed, 13 Dec 2023, Dave Chinner wrote: > > > On Tue, Dec 12, 2023 at 09:15:29AM -0800, Frank Filz wrote: > > > > > On Tue, Dec 12, 2023 at 10:10:23AM +0100, Donald Buczek wrote: > > > > > >

Re: file handle in statx (was: Re: How to cope with subvolumes and snapshots on muti-user systems?)

2023-12-12 Thread NeilBrown
On Wed, 13 Dec 2023, Dave Chinner wrote: > > What you are suggesting is that we now duplicate filehandle encoding > into every filesystem's statx() implementation. That's a bad > trade-off from a maintenance, testing and consistency POV because > now we end up with lots of individual, filehandle

Re: file handle in statx (was: Re: How to cope with subvolumes and snapshots on muti-user systems?)

2023-12-12 Thread NeilBrown
On Wed, 13 Dec 2023, Dave Chinner wrote: > On Tue, Dec 12, 2023 at 10:21:53AM -0500, Kent Overstreet wrote: > > On Tue, Dec 12, 2023 at 04:53:28PM +1100, Dave Chinner wrote: > > > Doesn't anyone else see or hear the elephant trumpeting loudly in > > > the middle of the room? > > > > > > I mean,

Re: file handle in statx (was: Re: How to cope with subvolumes and snapshots on muti-user systems?)

2023-12-12 Thread NeilBrown
On Wed, 13 Dec 2023, Miklos Szeredi wrote: > On Tue, 12 Dec 2023 at 17:08, Kent Overstreet > wrote: > > > In short, STATX_ATTR_INUM_NOT_UNIQUE is required to tell userspace when > > they _must_ do the new thing if they care about correctness; it provides > > a way to tell userspace what

Re: file handle in statx (was: Re: How to cope with subvolumes and snapshots on muti-user systems?)

2023-12-12 Thread Kent Overstreet
On Wed, Dec 13, 2023 at 07:48:16AM +1100, Dave Chinner wrote: > On Tue, Dec 12, 2023 at 10:21:53AM -0500, Kent Overstreet wrote: > > On Tue, Dec 12, 2023 at 04:53:28PM +1100, Dave Chinner wrote: > > > Doesn't anyone else see or hear the elephant trumpeting loudly in > > > the middle of the room? >

Re: file handle in statx

2023-12-12 Thread Dave Chinner
On Tue, Dec 12, 2023 at 09:15:29AM -0800, Frank Filz wrote: > > On Tue, Dec 12, 2023 at 10:10:23AM +0100, Donald Buczek wrote: > > > On 12/12/23 06:53, Dave Chinner wrote: > > > > > > > So can someone please explain to me why we need to try to re-invent > > > > a generic filehandle concept in

Re: file handle in statx (was: Re: How to cope with subvolumes and snapshots on muti-user systems?)

2023-12-12 Thread Dave Chinner
On Tue, Dec 12, 2023 at 10:21:53AM -0500, Kent Overstreet wrote: > On Tue, Dec 12, 2023 at 04:53:28PM +1100, Dave Chinner wrote: > > Doesn't anyone else see or hear the elephant trumpeting loudly in > > the middle of the room? > > > > I mean, we already have name_to_handle_at() for userspace to

RE: file handle in statx

2023-12-12 Thread Frank Filz
> On Tue, Dec 12, 2023 at 7:44 PM Kent Overstreet > wrote: > > > > On Tue, Dec 12, 2023 at 09:15:29AM -0800, Frank Filz wrote: > > > > On Tue, Dec 12, 2023 at 10:10:23AM +0100, Donald Buczek wrote: > > > > > On 12/12/23 06:53, Dave Chinner wrote: > > > > > > > > > > > So can someone please

Re: file handle in statx

2023-12-12 Thread Amir Goldstein
On Tue, Dec 12, 2023 at 7:44 PM Kent Overstreet wrote: > > On Tue, Dec 12, 2023 at 09:15:29AM -0800, Frank Filz wrote: > > > On Tue, Dec 12, 2023 at 10:10:23AM +0100, Donald Buczek wrote: > > > > On 12/12/23 06:53, Dave Chinner wrote: > > > > > > > > > So can someone please explain to me why we

Re: file handle in statx

2023-12-12 Thread Kent Overstreet
On Tue, Dec 12, 2023 at 09:15:29AM -0800, Frank Filz wrote: > > On Tue, Dec 12, 2023 at 10:10:23AM +0100, Donald Buczek wrote: > > > On 12/12/23 06:53, Dave Chinner wrote: > > > > > > > So can someone please explain to me why we need to try to re-invent > > > > a generic filehandle concept in

RE: file handle in statx

2023-12-12 Thread Frank Filz
> On Tue, Dec 12, 2023 at 10:10:23AM +0100, Donald Buczek wrote: > > On 12/12/23 06:53, Dave Chinner wrote: > > > > > So can someone please explain to me why we need to try to re-invent > > > a generic filehandle concept in statx when we already have a have > > > working and widely supported user

Re: file handle in statx (was: Re: How to cope with subvolumes and snapshots on muti-user systems?)

2023-12-12 Thread Kent Overstreet
On Tue, Dec 12, 2023 at 05:30:23PM +0100, Miklos Szeredi wrote: > On Tue, 12 Dec 2023 at 17:08, Kent Overstreet > wrote: > > > In short, STATX_ATTR_INUM_NOT_UNIQUE is required to tell userspace when > > they _must_ do the new thing if they care about correctness; it provides > > a way to tell

Re: file handle in statx (was: Re: How to cope with subvolumes and snapshots on muti-user systems?)

2023-12-12 Thread Miklos Szeredi
On Tue, 12 Dec 2023 at 17:08, Kent Overstreet wrote: > In short, STATX_ATTR_INUM_NOT_UNIQUE is required to tell userspace when > they _must_ do the new thing if they care about correctness; it provides > a way to tell userspace what guarantees we're able to provide. That flag would not help

Re: file handle in statx (was: Re: How to cope with subvolumes and snapshots on muti-user systems?)

2023-12-12 Thread Kent Overstreet
On Tue, Dec 12, 2023 at 04:57:41PM +0100, Miklos Szeredi wrote: > On Tue, 12 Dec 2023 at 16:43, Kent Overstreet > wrote: > > > > On Tue, Dec 12, 2023 at 04:38:29PM +0100, Miklos Szeredi wrote: > > > On Tue, 12 Dec 2023 at 16:35, Kent Overstreet > > > wrote: > > > > > > > Other poeple have been

Re: file handle in statx (was: Re: How to cope with subvolumes and snapshots on muti-user systems?)

2023-12-12 Thread Miklos Szeredi
On Tue, 12 Dec 2023 at 16:43, Kent Overstreet wrote: > > On Tue, Dec 12, 2023 at 04:38:29PM +0100, Miklos Szeredi wrote: > > On Tue, 12 Dec 2023 at 16:35, Kent Overstreet > > wrote: > > > > > Other poeple have been finding ways to contribute to the technical > > > discussion; just calling

Re: file handle in statx (was: Re: How to cope with subvolumes and snapshots on muti-user systems?)

2023-12-12 Thread Kent Overstreet
On Tue, Dec 12, 2023 at 04:38:29PM +0100, Miklos Szeredi wrote: > On Tue, 12 Dec 2023 at 16:35, Kent Overstreet > wrote: > > > Other poeple have been finding ways to contribute to the technical > > discussion; just calling things "ugly and broken" does not. > > Kent, calm down please. We call

Re: file handle in statx (was: Re: How to cope with subvolumes and snapshots on muti-user systems?)

2023-12-12 Thread Miklos Szeredi
On Tue, 12 Dec 2023 at 16:35, Kent Overstreet wrote: > Other poeple have been finding ways to contribute to the technical > discussion; just calling things "ugly and broken" does not. Kent, calm down please. We call things "ugly and broken" all the time. That's just an opinion, you are free

Re: file handle in statx (was: Re: How to cope with subvolumes and snapshots on muti-user systems?)

2023-12-12 Thread Kent Overstreet
On Tue, Dec 12, 2023 at 04:29:09PM +0100, Christian Brauner wrote: > On Tue, Dec 12, 2023 at 10:16:31AM -0500, Kent Overstreet wrote: > > On Tue, Dec 12, 2023 at 09:56:45AM +0100, Christian Brauner wrote: > > > On Tue, Dec 12, 2023 at 08:32:55AM +0200, Amir Goldstein wrote: > > > > > >

Re: file handle in statx (was: Re: How to cope with subvolumes and snapshots on muti-user systems?)

2023-12-12 Thread Christian Brauner
On Tue, Dec 12, 2023 at 10:16:31AM -0500, Kent Overstreet wrote: > On Tue, Dec 12, 2023 at 09:56:45AM +0100, Christian Brauner wrote: > > On Tue, Dec 12, 2023 at 08:32:55AM +0200, Amir Goldstein wrote: > > > > > STATX_ATTR_INUM_NOT_UNIQUE - it is possible that two files have the > > > > >

Re: file handle in statx (was: Re: How to cope with subvolumes and snapshots on muti-user systems?)

2023-12-12 Thread Kent Overstreet
On Tue, Dec 12, 2023 at 10:35:40AM +0100, Christian Brauner wrote: > On Tue, Dec 12, 2023 at 10:28:12AM +0100, Miklos Szeredi wrote: > > On Tue, 12 Dec 2023 at 10:23, Christian Brauner wrote: > > > > > > On Tue, Dec 12, 2023 at 09:10:47AM +, David Howells wrote: > > > > Christian Brauner

Re: file handle in statx (was: Re: How to cope with subvolumes and snapshots on muti-user systems?)

2023-12-12 Thread Christian Brauner
On Tue, Dec 12, 2023 at 03:06:07PM +0100, Miklos Szeredi wrote: > On Tue, 12 Dec 2023 at 14:48, Christian Brauner wrote: > > > Exposing the subvolume id in statx() is still fine imho. It's a concept > > shared between btrfs and bcachefs and it's pretty useful for interested > > userspace that

Re: file handle in statx (was: Re: How to cope with subvolumes and snapshots on muti-user systems?)

2023-12-12 Thread Kent Overstreet
On Tue, Dec 12, 2023 at 04:53:28PM +1100, Dave Chinner wrote: > Doesn't anyone else see or hear the elephant trumpeting loudly in > the middle of the room? > > I mean, we already have name_to_handle_at() for userspace to get a > unique, opaque, filesystem defined file handle for any given file. >

Re: file handle in statx

2023-12-12 Thread Theodore Ts'o
On Tue, Dec 12, 2023 at 10:10:23AM +0100, Donald Buczek wrote: > On 12/12/23 06:53, Dave Chinner wrote: > > > So can someone please explain to me why we need to try to re-invent > > a generic filehandle concept in statx when we already have a > > have working and widely supported user API that

Re: file handle in statx (was: Re: How to cope with subvolumes and snapshots on muti-user systems?)

2023-12-12 Thread Kent Overstreet
On Tue, Dec 12, 2023 at 09:56:45AM +0100, Christian Brauner wrote: > On Tue, Dec 12, 2023 at 08:32:55AM +0200, Amir Goldstein wrote: > > > > STATX_ATTR_INUM_NOT_UNIQUE - it is possible that two files have the > > > > same inode number > > This is just ugly with

Re: file handle in statx (was: Re: How to cope with subvolumes and snapshots on muti-user systems?)

2023-12-12 Thread Miklos Szeredi
On Tue, 12 Dec 2023 at 14:48, Christian Brauner wrote: > Exposing the subvolume id in statx() is still fine imho. It's a concept > shared between btrfs and bcachefs and it's pretty useful for interested > userspace that wants to make use of these apis. Exposing subvolume ID should be okay, as

Re: file handle in statx (was: Re: How to cope with subvolumes and snapshots on muti-user systems?)

2023-12-12 Thread Christian Brauner
On Tue, Dec 12, 2023 at 10:42:58AM +0100, Miklos Szeredi wrote: > On Tue, 12 Dec 2023 at 10:35, Christian Brauner wrote: > > > So taking a step back here, please. The original motivation for this > > discussion was restricted to handle btrfs - and now bcachefs as well. > > Both have a concept of

Re: file handle in statx (was: Re: How to cope with subvolumes and snapshots on muti-user systems?)

2023-12-12 Thread David Howells
Christian Brauner wrote: > > There is a upcoming potential problem where even the 64-bit field I placed > > in statx() may be insufficient. The Auristor AFS server, for example, has > > a 96-bit vnode ID, but I can't properly represent this in stx_ino. > > Currently, I > > Is that vnode ID

Re: file handle in statx (was: Re: How to cope with subvolumes and snapshots on muti-user systems?)

2023-12-12 Thread Miklos Szeredi
On Tue, 12 Dec 2023 at 10:35, Christian Brauner wrote: > So taking a step back here, please. The original motivation for this > discussion was restricted to handle btrfs - and now bcachefs as well. > Both have a concept of a subvolume so it made sense to go that route. > IOW, it wasn't

Re: file handle in statx (was: Re: How to cope with subvolumes and snapshots on muti-user systems?)

2023-12-12 Thread Christian Brauner
On Tue, Dec 12, 2023 at 10:28:12AM +0100, Miklos Szeredi wrote: > On Tue, 12 Dec 2023 at 10:23, Christian Brauner wrote: > > > > On Tue, Dec 12, 2023 at 09:10:47AM +, David Howells wrote: > > > Christian Brauner wrote: > > > > > > > > > > I suggest: > > > > > > > > > > > > > >

Re: file handle in statx (was: Re: How to cope with subvolumes and snapshots on muti-user systems?)

2023-12-12 Thread Miklos Szeredi
On Tue, 12 Dec 2023 at 10:23, Christian Brauner wrote: > > On Tue, Dec 12, 2023 at 09:10:47AM +, David Howells wrote: > > Christian Brauner wrote: > > > > > > > > I suggest: > > > > > > > > > > > > STATX_ATTR_INUM_NOT_UNIQUE - it is possible that two files have the > > > > > >

Re: file handle in statx (was: Re: How to cope with subvolumes and snapshots on muti-user systems?)

2023-12-12 Thread Christian Brauner
On Tue, Dec 12, 2023 at 09:10:47AM +, David Howells wrote: > Christian Brauner wrote: > > > > > > I suggest: > > > > > > > > > > STATX_ATTR_INUM_NOT_UNIQUE - it is possible that two files have the > > > > > same inode number > > > > This is just ugly with

Re: file handle in statx (was: Re: How to cope with subvolumes and snapshots on muti-user systems?)

2023-12-12 Thread David Howells
Christian Brauner wrote: > > > > I suggest: > > > > > > > > STATX_ATTR_INUM_NOT_UNIQUE - it is possible that two files have the > > > > same inode number > > This is just ugly with questionable value. A constant reminder of how > broken this is. Exposing the

Re: file handle in statx

2023-12-12 Thread Donald Buczek
On 12/12/23 06:53, Dave Chinner wrote: > So can someone please explain to me why we need to try to re-invent > a generic filehandle concept in statx when we already have a > have working and widely supported user API that provides exactly > this functionality? name_to_handle_at() is fine, but

Re: file handle in statx (was: Re: How to cope with subvolumes and snapshots on muti-user systems?)

2023-12-12 Thread Christian Brauner
On Tue, Dec 12, 2023 at 01:13:07PM +1100, NeilBrown wrote: > On Tue, 12 Dec 2023, Kent Overstreet wrote: > > On Tue, Dec 12, 2023 at 11:59:51AM +1100, NeilBrown wrote: > > > On Tue, 12 Dec 2023, Kent Overstreet wrote: > > > > NFSv4 specs that for the maximum size? That is pretty hefty... > > > >

Re: file handle in statx (was: Re: How to cope with subvolumes and snapshots on muti-user systems?)

2023-12-12 Thread Christian Brauner
On Tue, Dec 12, 2023 at 08:32:55AM +0200, Amir Goldstein wrote: > On Tue, Dec 12, 2023 at 7:53 AM Dave Chinner wrote: > > > > On Tue, Dec 12, 2023 at 11:59:51AM +1100, NeilBrown wrote: > > > On Tue, 12 Dec 2023, Kent Overstreet wrote: > > > > On Tue, Dec 12, 2023 at 10:53:07AM +1100, NeilBrown

Re: file handle in statx (was: Re: How to cope with subvolumes and snapshots on muti-user systems?)

2023-12-11 Thread David Howells
Dave Chinner wrote: > I mean, we already have name_to_handle_at() for userspace to get a > unique, opaque, filesystem defined file handle for any given file. > It's the same filehandle that filesystems hand to the nfsd so nfs > clients can uniquely identify the file they are asking the nfsd to >

Re: file handle in statx (was: Re: How to cope with subvolumes and snapshots on muti-user systems?)

2023-12-11 Thread Amir Goldstein
On Tue, Dec 12, 2023 at 7:53 AM Dave Chinner wrote: > > On Tue, Dec 12, 2023 at 11:59:51AM +1100, NeilBrown wrote: > > On Tue, 12 Dec 2023, Kent Overstreet wrote: > > > On Tue, Dec 12, 2023 at 10:53:07AM +1100, NeilBrown wrote: > > > > On Tue, 12 Dec 2023, Kent Overstreet wrote: > > > > > On Tue,

Re: file handle in statx (was: Re: How to cope with subvolumes and snapshots on muti-user systems?)

2023-12-11 Thread Dave Chinner
On Tue, Dec 12, 2023 at 11:59:51AM +1100, NeilBrown wrote: > On Tue, 12 Dec 2023, Kent Overstreet wrote: > > On Tue, Dec 12, 2023 at 10:53:07AM +1100, NeilBrown wrote: > > > On Tue, 12 Dec 2023, Kent Overstreet wrote: > > > > On Tue, Dec 12, 2023 at 09:43:27AM +1100, NeilBrown wrote: > > > > > On

Re: file handle in statx (was: Re: How to cope with subvolumes and snapshots on muti-user systems?)

2023-12-11 Thread Kent Overstreet
On Tue, Dec 12, 2023 at 01:13:07PM +1100, NeilBrown wrote: > On Tue, 12 Dec 2023, Kent Overstreet wrote: > > I suppose if we want to be able to round trip this stuff we do need to > > allocate space for it, even if a local filesystem would never include > > it. > > > > > I suggest: > > > > > >

Re: file handle in statx (was: Re: How to cope with subvolumes and snapshots on muti-user systems?)

2023-12-11 Thread NeilBrown
On Tue, 12 Dec 2023, Kent Overstreet wrote: > On Tue, Dec 12, 2023 at 11:59:51AM +1100, NeilBrown wrote: > > On Tue, 12 Dec 2023, Kent Overstreet wrote: > > > NFSv4 specs that for the maximum size? That is pretty hefty... > > > > It is - but it needs room to identify the filesystem and it needs

Re: file handle in statx (was: Re: How to cope with subvolumes and snapshots on muti-user systems?)

2023-12-11 Thread Kent Overstreet
On Tue, Dec 12, 2023 at 11:59:51AM +1100, NeilBrown wrote: > On Tue, 12 Dec 2023, Kent Overstreet wrote: > > NFSv4 specs that for the maximum size? That is pretty hefty... > > It is - but it needs room to identify the filesystem and it needs to be > stable across time. That need is more than a

Re: file handle in statx (was: Re: How to cope with subvolumes and snapshots on muti-user systems?)

2023-12-11 Thread NeilBrown
On Tue, 12 Dec 2023, Kent Overstreet wrote: > On Tue, Dec 12, 2023 at 10:53:07AM +1100, NeilBrown wrote: > > On Tue, 12 Dec 2023, Kent Overstreet wrote: > > > On Tue, Dec 12, 2023 at 09:43:27AM +1100, NeilBrown wrote: > > > > On Sat, 09 Dec 2023, Kent Overstreet wrote: > > > > > On Fri, Dec 08,

Re: file handle in statx (was: Re: How to cope with subvolumes and snapshots on muti-user systems?)

2023-12-11 Thread David Howells
NeilBrown wrote: > I'm not in favour of any filesystem depending on this for correct > functionality today. As long as the filesystem isn't so large that > inum+volnum simply cannot fit in 64 bits, we should make a reasonable > effort to present them both in 64 bits. The Auristor version of

Re: file handle in statx (was: Re: How to cope with subvolumes and snapshots on muti-user systems?)

2023-12-11 Thread Kent Overstreet
On Tue, Dec 12, 2023 at 10:53:07AM +1100, NeilBrown wrote: > On Tue, 12 Dec 2023, Kent Overstreet wrote: > > On Tue, Dec 12, 2023 at 09:43:27AM +1100, NeilBrown wrote: > > > On Sat, 09 Dec 2023, Kent Overstreet wrote: > > > > On Fri, Dec 08, 2023 at 12:34:28PM +0100, Donald Buczek wrote: > > > > >

Re: file handle in statx (was: Re: How to cope with subvolumes and snapshots on muti-user systems?)

2023-12-11 Thread NeilBrown
On Tue, 12 Dec 2023, Kent Overstreet wrote: > On Tue, Dec 12, 2023 at 09:43:27AM +1100, NeilBrown wrote: > > On Sat, 09 Dec 2023, Kent Overstreet wrote: > > > On Fri, Dec 08, 2023 at 12:34:28PM +0100, Donald Buczek wrote: > > > > On 12/8/23 03:49, Kent Overstreet wrote: > > > > > > > > > We

Re: file handle in statx (was: Re: How to cope with subvolumes and snapshots on muti-user systems?)

2023-12-11 Thread David Howells
Kent Overstreet wrote: > I was chatting a bit with David Howells on IRC about this, and floated > adding the file handle to statx. It looks like there's enough space > reserved to make this feasible - probably going with a fixed maximum > size of 128-256 bits. We can always save the last bit to