Re: [RFC 12/26] ext2 white-out support

2007-08-02 Thread Pavel Machek
Hi! > > > I wouldn't bother with setting the directory type field to be DT_WHT, > > > given that they will never be returned to userspace anyway. > > > > At the moment I still rely on this for the current readdir implementation. > > Viro already said that he doesn't want to see this (the readdir

Re: [RFC 12/26] ext2 white-out support

2007-08-02 Thread Jeremy Maitin-Shepard
Jörn Engel <[EMAIL PROTECTED]> writes: > On Wed, 1 August 2007 15:33:30 -0400, Josef Sipek wrote: >> >> This brings up an very interesting (but painful) question...which makes more >> sense? Allowing the modifications in only the top-most branch, or any branch >> (given the user allows it at moun

Re: [RFC 12/26] ext2 white-out support

2007-08-02 Thread Jörn Engel
On Wed, 1 August 2007 15:33:30 -0400, Josef Sipek wrote: > > This brings up an very interesting (but painful) question...which makes more > sense? Allowing the modifications in only the top-most branch, or any branch > (given the user allows it at mount-time)? > > This is really question to the

Re: [RFC 12/26] ext2 white-out support

2007-08-02 Thread Jan Blunck
On Thu, Aug 02, Ph. Marek wrote: > On Mittwoch, 1. August 2007, Josef Sipek wrote: > > Alright not the greatest of examples, there is something to be said about > > symmetry, so...let me try again :) > ... > > Oops! There's a whiteout in /b that hides the directory in /c -- rename(2) > > shouldn't

Re: [RFC 12/26] ext2 white-out support

2007-08-02 Thread Jan Blunck
On Wed, Aug 01, Erez Zadok wrote: > There are three other reasons why Unionfs and our users like to have > multiple writable branches: > ... >And yes, it does make our implementation more complex. And error-prone and unflexible wrt to changes. When XIP was introduced, unionfs crashed all o

Re: [RFC 12/26] ext2 white-out support

2007-08-02 Thread Jan Blunck
On Wed, Aug 01, Josef Sipek wrote: > This brings up an very interesting (but painful) question...which makes more > sense? Allowing the modifications in only the top-most branch, or any branch > (given the user allows it at mount-time)? My implementation is keeping things simple because of reason

Re: [RFC 12/26] ext2 white-out support

2007-08-02 Thread Jan Blunck
On Tue, Jul 31, Josef Sipek wrote: > > So you think that just because you mounted the filesystem somewhere else it > > should look different? This is what sharing is all about. If you share a > > filesystem you also share the removal of objects. > > The removal happens at the union level, not the

Re: [RFC 12/26] ext2 white-out support

2007-08-01 Thread Ph. Marek
On Mittwoch, 1. August 2007, Josef Sipek wrote: > Alright not the greatest of examples, there is something to be said about > symmetry, so...let me try again :) ... > Oops! There's a whiteout in /b that hides the directory in /c -- rename(2) > shouldn't make directory subtrees disappear. > > There

Re: [RFC 12/26] ext2 white-out support

2007-08-01 Thread Erez Zadok
In message <[EMAIL PROTECTED]>, Dave Kleikamp writes: > On Wed, 2007-08-01 at 15:33 -0400, Josef Sipek wrote: > > On Wed, Aug 01, 2007 at 02:10:31PM -0500, Dave Kleikamp wrote: > > > On Wed, 2007-08-01 at 14:44 -0400, Josef Sipek wrote: > > > > Now what? How do you rename? Do you rename in the same

Re: [RFC 12/26] ext2 white-out support

2007-08-01 Thread Dave Kleikamp
On Wed, 2007-08-01 at 15:33 -0400, Josef Sipek wrote: > On Wed, Aug 01, 2007 at 02:10:31PM -0500, Dave Kleikamp wrote: > > On Wed, 2007-08-01 at 14:44 -0400, Josef Sipek wrote: > > > Now what? How do you rename? Do you rename in the same branch (assuming it > > > is rw)? > > > > Er, no. According

Re: [RFC 12/26] ext2 white-out support

2007-08-01 Thread Josef Sipek
On Wed, Aug 01, 2007 at 02:10:31PM -0500, Dave Kleikamp wrote: > On Wed, 2007-08-01 at 14:44 -0400, Josef Sipek wrote: > > Alright not the greatest of examples, there is something to be said about > > symmetry, so...let me try again :) > > > > /a/ > > /b/bar (whiteout for bar) > > /c/

Re: [RFC 12/26] ext2 white-out support

2007-08-01 Thread Dave Kleikamp
On Wed, 2007-08-01 at 14:44 -0400, Josef Sipek wrote: > Alright not the greatest of examples, there is something to be said about > symmetry, so...let me try again :) > > /a/ > /b/bar(whiteout for bar) > /c/foo/qwerty > > Now, let's mount a union of {a,b,c}, and we'll see: > > $

Re: [RFC 12/26] ext2 white-out support

2007-08-01 Thread Josef Sipek
On Wed, Aug 01, 2007 at 10:23:29AM -0500, Dave Kleikamp wrote: > On Tue, 2007-07-31 at 13:11 -0400, Josef Sipek wrote: > > On Tue, Jul 31, 2007 at 07:00:12PM +0200, Jan Blunck wrote: > > > On Tue, Jul 31, Josef Sipek wrote: > > > > > > > On Mon, Jul 30, 2007 at 06:13:35PM +0200, Jan Blunck wrote:

Re: [RFC 12/26] ext2 white-out support

2007-08-01 Thread Josef Sipek
On Wed, Aug 01, 2007 at 07:58:49PM +0200, Jan Engelhardt wrote: > > On Jul 31 2007 12:36, Josef Sipek wrote: > >[2] http://www.filesystems.org/unionfs-odf.txt > > >Instead, the new ODF code stores whiteouts as hardlinks to a special > >(regular) zero-length file in odf (/odf/whiteout), and it sto

Re: [RFC 12/26] ext2 white-out support

2007-08-01 Thread Jan Engelhardt
On Aug 1 2007 12:00, Hans-Peter Jansen wrote: > >*) The amount of administration work of any (necessary, unfortunately) >VMware XP instance running on top of those diskless clients excels that of >all diskless clients by an order of magnitude. Hardly :) Install XP, snapshot it when done. Copy .

Re: [RFC 12/26] ext2 white-out support

2007-08-01 Thread Jan Engelhardt
On Jul 31 2007 12:36, Josef Sipek wrote: >[2] http://www.filesystems.org/unionfs-odf.txt >Instead, the new ODF code stores whiteouts as hardlinks to a special >(regular) zero-length file in odf (/odf/whiteout), and it stores opaqueness >information for directories in the inode GID bits in an ODF

Re: [RFC 12/26] ext2 white-out support

2007-08-01 Thread Dave Kleikamp
On Tue, 2007-07-31 at 13:11 -0400, Josef Sipek wrote: > On Tue, Jul 31, 2007 at 07:00:12PM +0200, Jan Blunck wrote: > > On Tue, Jul 31, Josef Sipek wrote: > > > > > On Mon, Jul 30, 2007 at 06:13:35PM +0200, Jan Blunck wrote: > > > > Introduce white-out support to ext2. > > > > > > I think storing

Re: [RFC 12/26] ext2 white-out support

2007-08-01 Thread Josef Sipek
On Wed, Aug 01, 2007 at 12:00:42PM +0200, Hans-Peter Jansen wrote: > Am Dienstag, 31. Juli 2007 19:00 schrieb Jan Blunck: > > On Tue, Jul 31, Josef Sipek wrote: > > > On Mon, Jul 30, 2007 at 06:13:35PM +0200, Jan Blunck wrote: > > > > Introduce white-out support to ext2. > > > > > > I think storing

Re: [RFC 12/26] ext2 white-out support

2007-08-01 Thread Hans-Peter Jansen
Am Dienstag, 31. Juli 2007 19:00 schrieb Jan Blunck: > On Tue, Jul 31, Josef Sipek wrote: > > On Mon, Jul 30, 2007 at 06:13:35PM +0200, Jan Blunck wrote: > > > Introduce white-out support to ext2. > > > > I think storing whiteouts on the branches is wrong. It creates all sort > > of nasty cases whe

Re: [RFC 12/26] ext2 white-out support

2007-07-31 Thread Mark Williamson
> Really the only sane way of keeping track of whiteouts seems some external > store. We did an experiment with Unionfs, and moving the whiteout handling > to effectively a "library" that did all the dirty work cleaned up the code > considerably [2,3]. What about keeping track of whiteouts in a sp

Re: [RFC 12/26] ext2 white-out support

2007-07-31 Thread Josef Sipek
On Tue, Jul 31, 2007 at 06:03:06PM +0100, Mark Williamson wrote: > > Really the only sane way of keeping track of whiteouts seems some external > > store. We did an experiment with Unionfs, and moving the whiteout handling > > to effectively a "library" that did all the dirty work cleaned up the co

Re: [RFC 12/26] ext2 white-out support

2007-07-31 Thread Josef Sipek
On Tue, Jul 31, 2007 at 07:00:12PM +0200, Jan Blunck wrote: > On Tue, Jul 31, Josef Sipek wrote: > > > On Mon, Jul 30, 2007 at 06:13:35PM +0200, Jan Blunck wrote: > > > Introduce white-out support to ext2. > > > > I think storing whiteouts on the branches is wrong. It creates all sort of > > nast

Re: [RFC 12/26] ext2 white-out support

2007-07-31 Thread Jan Blunck
On Tue, Jul 31, Josef Sipek wrote: > On Mon, Jul 30, 2007 at 06:13:35PM +0200, Jan Blunck wrote: > > Introduce white-out support to ext2. > > I think storing whiteouts on the branches is wrong. It creates all sort of > nasty cases when people actually try to use unioning. Imagine a (no-so > unlik

Re: [RFC 12/26] ext2 white-out support

2007-07-31 Thread Josef Sipek
On Mon, Jul 30, 2007 at 06:13:35PM +0200, Jan Blunck wrote: > Introduce white-out support to ext2. I think storing whiteouts on the branches is wrong. It creates all sort of nasty cases when people actually try to use unioning. Imagine a (no-so unlikely) scenario where you have 2 unions, and they

Re: [RFC 12/26] ext2 white-out support

2007-07-31 Thread Theodore Tso
On Tue, Jul 31, 2007 at 09:44:36AM +0200, Jan Blunck wrote: > Ok, this is pretty similar to the way I implemented this for tmpfs. The > problem is that the union mount code is explicitly checking if the filesystem > is supporting whiteout. I used to use a new filesystem flag (FS_WHITEOUT) for > thi

Re: [RFC 12/26] ext2 white-out support

2007-07-31 Thread Jan Blunck
On Tue, Jul 31, Andreas Dilger wrote: > On Jul 31, 2007 09:44 +0200, Jan Blunck wrote: > > Ok, this is pretty similar to the way I implemented this for tmpfs. The > > problem is that the union mount code is explicitly checking if the > > filesystem > > is supporting whiteout. I used to use a new

Re: [RFC 12/26] ext2 white-out support

2007-07-31 Thread Andreas Dilger
On Jul 31, 2007 09:44 +0200, Jan Blunck wrote: > Ok, this is pretty similar to the way I implemented this for tmpfs. The > problem is that the union mount code is explicitly checking if the filesystem > is supporting whiteout. I used to use a new filesystem flag (FS_WHITEOUT) for > this but though

Re: [RFC 12/26] ext2 white-out support

2007-07-31 Thread Jan Blunck
On Mon, Jul 30, Theodore Tso wrote: > On Mon, Jul 30, 2007 at 06:13:35PM +0200, Jan Blunck wrote: > > Introduce white-out support to ext2. > > > > Known Bugs: > > - Needs a reserved inode number for white-outs > > You picked different reserved inodes for the ext2 and ext3 > filesystems. That's

Re: [RFC 12/26] ext2 white-out support

2007-07-30 Thread Theodore Tso
On Mon, Jul 30, 2007 at 06:13:35PM +0200, Jan Blunck wrote: > Introduce white-out support to ext2. > > Known Bugs: > - Needs a reserved inode number for white-outs You picked different reserved inodes for the ext2 and ext3 filesystems. That's good for a NACK right there. The codepoints (i.e., r