Re: unionfs unusable on multiuser systems (was Re: [PATCH 01/24] Unionfs: Documentation)

2007-01-12 Thread Shaya Potter
Pavel Machek wrote: Hi! That statement is meant to scare people away from modifying the lower fs :) I tortured unionfs quite a bit, and it can oops but it takes some effort. But isn't it then potential DOS? If you happen to union two filesystems and an untrusted user has write access to

unionfs unusable on multiuser systems (was Re: [PATCH 01/24] Unionfs: Documentation)

2007-01-12 Thread Pavel Machek
Hi! > > > That statement is meant to scare people away from modifying the lower fs > > > :) > > > I tortured unionfs quite a bit, and it can oops but it takes some effort. > > But isn't it then potential DOS? If you happen to union two filesystems > > and an untrusted user has write access to

unionfs unusable on multiuser systems (was Re: [PATCH 01/24] Unionfs: Documentation)

2007-01-12 Thread Pavel Machek
Hi! That statement is meant to scare people away from modifying the lower fs :) I tortured unionfs quite a bit, and it can oops but it takes some effort. But isn't it then potential DOS? If you happen to union two filesystems and an untrusted user has write access to both original

Re: unionfs unusable on multiuser systems (was Re: [PATCH 01/24] Unionfs: Documentation)

2007-01-12 Thread Shaya Potter
Pavel Machek wrote: Hi! That statement is meant to scare people away from modifying the lower fs :) I tortured unionfs quite a bit, and it can oops but it takes some effort. But isn't it then potential DOS? If you happen to union two filesystems and an untrusted user has write access to

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-11 Thread Jan Kara
> Josef Sipek wrote: > >On Wed, Jan 10, 2007 at 05:12:15PM +0100, Jan Kara wrote: > >> I see :). To me it just sounds as if you want to do remount-read-only > >>for source filesystems, which is operation we support perfectly fine, > >>and after that create union mount. But I agree you cannot do

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-11 Thread Jan Kara
Josef Sipek wrote: On Wed, Jan 10, 2007 at 05:12:15PM +0100, Jan Kara wrote: I see :). To me it just sounds as if you want to do remount-read-only for source filesystems, which is operation we support perfectly fine, and after that create union mount. But I agree you cannot do quite that

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-10 Thread Shaya Potter
Josef Sipek wrote: On Wed, Jan 10, 2007 at 05:12:15PM +0100, Jan Kara wrote: I see :). To me it just sounds as if you want to do remount-read-only for source filesystems, which is operation we support perfectly fine, and after that create union mount. But I agree you cannot do quite that

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-10 Thread Josef Sipek
On Wed, Jan 10, 2007 at 05:12:15PM +0100, Jan Kara wrote: > I see :). To me it just sounds as if you want to do remount-read-only > for source filesystems, which is operation we support perfectly fine, > and after that create union mount. But I agree you cannot do quite that > since you need to

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-10 Thread Jan Kara
> In message <[EMAIL PROTECTED]>, Jan Kara writes: > > > In message <[EMAIL PROTECTED]>, Jan Kara writes: > [...] > > > Jan, all of it is duable: we can downgrade the f/s to readonly, grab > > > various > > > locks, search through various lists looking for open fd's and such, then > > > decide if

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-10 Thread Shaya Potter
Erez Zadok wrote: I didn't know about those patches, but yes, they do sound useful. I'm curious who needed such functionality before and why. If someone can point me to those patches, we can look into using them for Unionfs. Thanks. I asked for it years ago, You can probably guess why :)

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-10 Thread Erez Zadok
In message <[EMAIL PROTECTED]>, Jan Kara writes: > > In message <[EMAIL PROTECTED]>, Jan Kara writes: [...] > > Jan, all of it is duable: we can downgrade the f/s to readonly, grab various > > locks, search through various lists looking for open fd's and such, then > > decide if to allow the mount

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-10 Thread Jan Kara
> In message <[EMAIL PROTECTED]>, Jan Kara writes: > > > In message <[EMAIL PROTECTED]>, Andrew Morton writes: > > > > On Sun, 7 Jan 2007 23:12:53 -0500 > > > > "Josef 'Jeff' Sipek" <[EMAIL PROTECTED]> wrote: > > > > > > > > > +Modifying a Unionfs branch directly, while the union is mounted, is

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-10 Thread Jan Kara
In message [EMAIL PROTECTED], Jan Kara writes: In message [EMAIL PROTECTED], Andrew Morton writes: On Sun, 7 Jan 2007 23:12:53 -0500 Josef 'Jeff' Sipek [EMAIL PROTECTED] wrote: +Modifying a Unionfs branch directly, while the union is mounted, is +currently unsupported.

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-10 Thread Erez Zadok
In message [EMAIL PROTECTED], Jan Kara writes: In message [EMAIL PROTECTED], Jan Kara writes: [...] Jan, all of it is duable: we can downgrade the f/s to readonly, grab various locks, search through various lists looking for open fd's and such, then decide if to allow the mount or not.

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-10 Thread Shaya Potter
Erez Zadok wrote: I didn't know about those patches, but yes, they do sound useful. I'm curious who needed such functionality before and why. If someone can point me to those patches, we can look into using them for Unionfs. Thanks. I asked for it years ago, You can probably guess why :)

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-10 Thread Jan Kara
In message [EMAIL PROTECTED], Jan Kara writes: In message [EMAIL PROTECTED], Jan Kara writes: [...] Jan, all of it is duable: we can downgrade the f/s to readonly, grab various locks, search through various lists looking for open fd's and such, then decide if to allow the mount

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-10 Thread Josef Sipek
On Wed, Jan 10, 2007 at 05:12:15PM +0100, Jan Kara wrote: I see :). To me it just sounds as if you want to do remount-read-only for source filesystems, which is operation we support perfectly fine, and after that create union mount. But I agree you cannot do quite that since you need to have

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-10 Thread Shaya Potter
Josef Sipek wrote: On Wed, Jan 10, 2007 at 05:12:15PM +0100, Jan Kara wrote: I see :). To me it just sounds as if you want to do remount-read-only for source filesystems, which is operation we support perfectly fine, and after that create union mount. But I agree you cannot do quite that

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-09 Thread Jan Engelhardt
On Jan 9 2007 11:41, Shaya Potter wrote: > >Again, what about fibre channel support? Imagine I have multiple blades >connected to a SAN. For whatever reason I format the san w/ ext3 (I've >actually done this when we didn't need sharing, just needed a huge disk, >for instance for doing

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-09 Thread Erez Zadok
In message <[EMAIL PROTECTED]>, "Raz Ben-Jehuda(caro)" writes: > On 1/9/07, Erez Zadok <[EMAIL PROTECTED]> wrote: > > In message <[EMAIL PROTECTED]>, Christoph Hellwig writes: > > > On Mon, Jan 08, 2007 at 07:03:35PM -0500, Erez Zadok wrote: > > > > However, I must caution that a file system like

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-09 Thread Raz Ben-Jehuda(caro)
On 1/9/07, Erez Zadok <[EMAIL PROTECTED]> wrote: In message <[EMAIL PROTECTED]>, Christoph Hellwig writes: > On Mon, Jan 08, 2007 at 07:03:35PM -0500, Erez Zadok wrote: > > However, I must caution that a file system like ecryptfs is very different > > from Unionfs, the latter being a fan-out

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-09 Thread Erez Zadok
In message <[EMAIL PROTECTED]>, Christoph Hellwig writes: > On Mon, Jan 08, 2007 at 07:03:35PM -0500, Erez Zadok wrote: > > However, I must caution that a file system like ecryptfs is very different > > from Unionfs, the latter being a fan-out file system---and both have very > > different goals.

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-09 Thread Erez Zadok
In message <[EMAIL PROTECTED]>, Jan Kara writes: > > In message <[EMAIL PROTECTED]>, Andrew Morton writes: > > > On Sun, 7 Jan 2007 23:12:53 -0500 > > > "Josef 'Jeff' Sipek" <[EMAIL PROTECTED]> wrote: > > > > > > > +Modifying a Unionfs branch directly, while the union is mounted, is > > > >

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-09 Thread Erez Zadok
In message <[EMAIL PROTECTED]>, Trond Myklebust writes: > I'm saying that at the very least it should not Oops in these > situations. As to whether or not they are something you want to handle > more gracefully, that is up to you, but Oopses are definitely a > showstopper. > > Trond I totally

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-09 Thread Jan Kara
> On Tue, 2007-01-09 at 11:30 -0500, Trond Myklebust wrote: > > On Tue, 2007-01-09 at 13:15 +0100, Jan Kara wrote: > > > > On Mon, Jan 08, 2007 at 11:18:52AM -0800, Andrew Morton wrote: > > > > > On Sun, 7 Jan 2007 23:12:53 -0500 > > > > > "Josef 'Jeff' Sipek" <[EMAIL PROTECTED]> wrote: > > > > >

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-09 Thread Shaya Potter
On Tue, 2007-01-09 at 12:03 -0500, Trond Myklebust wrote: > I'm saying that at the very least it should not Oops in these > situations. As to whether or not they are something you want to handle > more gracefully, that is up to you, but Oopses are definitely a > showstopper. I don't think anyone

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-09 Thread Trond Myklebust
On Tue, 2007-01-09 at 18:04 +0100, Jan Kara wrote: > But once you have MS_RDONLY set, there should be no modifications of > the underlying filesystem, should they? And I have understood that the > only problem is modifying the filesystem underneath unionfs. But maybe > I'm missing something.

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-09 Thread Jan Kara
> On Tue, 2007-01-09 at 13:26 +0100, Jan Kara wrote: > > Yes, making fs readonly at VFS level would not work for already opened > > files. But you if you create new union, you could lock down the > > filesystems you are unioning (via s_umount semaphore), go through lists > > of all open fd's on

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-09 Thread Trond Myklebust
On Tue, 2007-01-09 at 11:41 -0500, Shaya Potter wrote: > On Tue, 2007-01-09 at 11:30 -0500, Trond Myklebust wrote: > > You mean somebody like, say, a perfectly innocent process working on the > > NFS server or some other client that is oblivious to the existence of > > unionfs stacks on your

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-09 Thread Shaya Potter
On Tue, 2007-01-09 at 11:30 -0500, Trond Myklebust wrote: > On Tue, 2007-01-09 at 13:15 +0100, Jan Kara wrote: > > > On Mon, Jan 08, 2007 at 11:18:52AM -0800, Andrew Morton wrote: > > > > On Sun, 7 Jan 2007 23:12:53 -0500 > > > > "Josef 'Jeff' Sipek" <[EMAIL PROTECTED]> wrote: > > > > > > > >

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-09 Thread Trond Myklebust
On Tue, 2007-01-09 at 13:26 +0100, Jan Kara wrote: > Yes, making fs readonly at VFS level would not work for already opened > files. But you if you create new union, you could lock down the > filesystems you are unioning (via s_umount semaphore), go through lists > of all open fd's on those

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-09 Thread Trond Myklebust
On Tue, 2007-01-09 at 13:15 +0100, Jan Kara wrote: > > On Mon, Jan 08, 2007 at 11:18:52AM -0800, Andrew Morton wrote: > > > On Sun, 7 Jan 2007 23:12:53 -0500 > > > "Josef 'Jeff' Sipek" <[EMAIL PROTECTED]> wrote: > > > > > > > > > Any such change can cause Unionfs to oops, or stay > > > >

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-09 Thread Jan Kara
> In message <[EMAIL PROTECTED]>, Andrew Morton writes: > > On Sun, 7 Jan 2007 23:12:53 -0500 > > "Josef 'Jeff' Sipek" <[EMAIL PROTECTED]> wrote: > > > > > +Modifying a Unionfs branch directly, while the union is mounted, is > > > +currently unsupported. > > > > Does this mean that if I have

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-09 Thread Jan Kara
> On Mon, Jan 08, 2007 at 11:18:52AM -0800, Andrew Morton wrote: > > On Sun, 7 Jan 2007 23:12:53 -0500 > > "Josef 'Jeff' Sipek" <[EMAIL PROTECTED]> wrote: > > > > > Any such change can cause Unionfs to oops, or stay > > > silent and even RESULT IN DATA LOSS. > > > > With a rather rough user

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-09 Thread Christoph Hellwig
On Tue, Jan 09, 2007 at 05:43:33AM -0500, Josef Sipek wrote: > > I think that's an very important point. We have a chance to get that > > non-fanout filesystems right quite easily - something I wished that would > > have been done before the ecryptfs merge - while getting fan-out stackable > >

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-09 Thread Christoph Hellwig
On Tue, Jan 09, 2007 at 05:43:33AM -0500, Josef Sipek wrote: > RAIF is another fan-out stackable fs with much more complex logic. (Just the > other day, I saw an announcement for a new version on fsdevel.) I didn't say none exist, but rather none is useful. While RAIF is definitly an excellent

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-09 Thread Josef Sipek
On Tue, Jan 09, 2007 at 09:53:45AM +, Christoph Hellwig wrote: > On Mon, Jan 08, 2007 at 07:03:35PM -0500, Erez Zadok wrote: > > However, I must caution that a file system like ecryptfs is very different > > from Unionfs, the latter being a fan-out file system---and both have very > >

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-09 Thread Josef Sipek
On Tue, Jan 09, 2007 at 09:49:35AM +, Christoph Hellwig wrote: > On Mon, Jan 08, 2007 at 06:25:16PM -0500, Josef Sipek wrote: > > > There's no such problem with bind mounts. It's surprising to see such a > > > restriction with union mounts. > > > > Bind mounts are a purely VFS level

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-09 Thread Christoph Hellwig
On Mon, Jan 08, 2007 at 07:03:35PM -0500, Erez Zadok wrote: > However, I must caution that a file system like ecryptfs is very different > from Unionfs, the latter being a fan-out file system---and both have very > different goals. The common code between the two file systems, at this > stage, is

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-09 Thread Christoph Hellwig
On Mon, Jan 08, 2007 at 06:25:16PM -0500, Josef Sipek wrote: > > There's no such problem with bind mounts. It's surprising to see such a > > restriction with union mounts. > > Bind mounts are a purely VFS level construct. Unionfs is, as the name > implies, a filesystem. Last year at OLS, it

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-09 Thread Raz Ben-Jehuda(caro)
On 1/9/07, Erez Zadok [EMAIL PROTECTED] wrote: In message [EMAIL PROTECTED], Christoph Hellwig writes: On Mon, Jan 08, 2007 at 07:03:35PM -0500, Erez Zadok wrote: However, I must caution that a file system like ecryptfs is very different from Unionfs, the latter being a fan-out file

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-09 Thread Erez Zadok
In message [EMAIL PROTECTED], Raz Ben-Jehuda(caro) writes: On 1/9/07, Erez Zadok [EMAIL PROTECTED] wrote: In message [EMAIL PROTECTED], Christoph Hellwig writes: On Mon, Jan 08, 2007 at 07:03:35PM -0500, Erez Zadok wrote: However, I must caution that a file system like ecryptfs is very

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-09 Thread Christoph Hellwig
On Mon, Jan 08, 2007 at 06:25:16PM -0500, Josef Sipek wrote: There's no such problem with bind mounts. It's surprising to see such a restriction with union mounts. Bind mounts are a purely VFS level construct. Unionfs is, as the name implies, a filesystem. Last year at OLS, it seemed that

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-09 Thread Christoph Hellwig
On Mon, Jan 08, 2007 at 07:03:35PM -0500, Erez Zadok wrote: However, I must caution that a file system like ecryptfs is very different from Unionfs, the latter being a fan-out file system---and both have very different goals. The common code between the two file systems, at this stage, is not

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-09 Thread Josef Sipek
On Tue, Jan 09, 2007 at 09:49:35AM +, Christoph Hellwig wrote: On Mon, Jan 08, 2007 at 06:25:16PM -0500, Josef Sipek wrote: There's no such problem with bind mounts. It's surprising to see such a restriction with union mounts. Bind mounts are a purely VFS level construct. Unionfs

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-09 Thread Josef Sipek
On Tue, Jan 09, 2007 at 09:53:45AM +, Christoph Hellwig wrote: On Mon, Jan 08, 2007 at 07:03:35PM -0500, Erez Zadok wrote: However, I must caution that a file system like ecryptfs is very different from Unionfs, the latter being a fan-out file system---and both have very different

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-09 Thread Christoph Hellwig
On Tue, Jan 09, 2007 at 05:43:33AM -0500, Josef Sipek wrote: RAIF is another fan-out stackable fs with much more complex logic. (Just the other day, I saw an announcement for a new version on fsdevel.) I didn't say none exist, but rather none is useful. While RAIF is definitly an excellent

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-09 Thread Christoph Hellwig
On Tue, Jan 09, 2007 at 05:43:33AM -0500, Josef Sipek wrote: I think that's an very important point. We have a chance to get that non-fanout filesystems right quite easily - something I wished that would have been done before the ecryptfs merge - while getting fan-out stackable

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-09 Thread Jan Kara
On Mon, Jan 08, 2007 at 11:18:52AM -0800, Andrew Morton wrote: On Sun, 7 Jan 2007 23:12:53 -0500 Josef 'Jeff' Sipek [EMAIL PROTECTED] wrote: snip Any such change can cause Unionfs to oops, or stay silent and even RESULT IN DATA LOSS. With a rather rough user interface ;)

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-09 Thread Jan Kara
In message [EMAIL PROTECTED], Andrew Morton writes: On Sun, 7 Jan 2007 23:12:53 -0500 Josef 'Jeff' Sipek [EMAIL PROTECTED] wrote: +Modifying a Unionfs branch directly, while the union is mounted, is +currently unsupported. Does this mean that if I have /a/b/ and /c/d/ unionised

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-09 Thread Trond Myklebust
On Tue, 2007-01-09 at 13:15 +0100, Jan Kara wrote: On Mon, Jan 08, 2007 at 11:18:52AM -0800, Andrew Morton wrote: On Sun, 7 Jan 2007 23:12:53 -0500 Josef 'Jeff' Sipek [EMAIL PROTECTED] wrote: snip Any such change can cause Unionfs to oops, or stay silent and even RESULT

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-09 Thread Trond Myklebust
On Tue, 2007-01-09 at 13:26 +0100, Jan Kara wrote: Yes, making fs readonly at VFS level would not work for already opened files. But you if you create new union, you could lock down the filesystems you are unioning (via s_umount semaphore), go through lists of all open fd's on those

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-09 Thread Shaya Potter
On Tue, 2007-01-09 at 11:30 -0500, Trond Myklebust wrote: On Tue, 2007-01-09 at 13:15 +0100, Jan Kara wrote: On Mon, Jan 08, 2007 at 11:18:52AM -0800, Andrew Morton wrote: On Sun, 7 Jan 2007 23:12:53 -0500 Josef 'Jeff' Sipek [EMAIL PROTECTED] wrote: snip Any such

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-09 Thread Trond Myklebust
On Tue, 2007-01-09 at 11:41 -0500, Shaya Potter wrote: On Tue, 2007-01-09 at 11:30 -0500, Trond Myklebust wrote: You mean somebody like, say, a perfectly innocent process working on the NFS server or some other client that is oblivious to the existence of unionfs stacks on your particular

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-09 Thread Jan Kara
On Tue, 2007-01-09 at 13:26 +0100, Jan Kara wrote: Yes, making fs readonly at VFS level would not work for already opened files. But you if you create new union, you could lock down the filesystems you are unioning (via s_umount semaphore), go through lists of all open fd's on those

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-09 Thread Trond Myklebust
On Tue, 2007-01-09 at 18:04 +0100, Jan Kara wrote: But once you have MS_RDONLY set, there should be no modifications of the underlying filesystem, should they? And I have understood that the only problem is modifying the filesystem underneath unionfs. But maybe I'm missing something. Remote

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-09 Thread Shaya Potter
On Tue, 2007-01-09 at 12:03 -0500, Trond Myklebust wrote: I'm saying that at the very least it should not Oops in these situations. As to whether or not they are something you want to handle more gracefully, that is up to you, but Oopses are definitely a showstopper. I don't think anyone

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-09 Thread Jan Kara
On Tue, 2007-01-09 at 11:30 -0500, Trond Myklebust wrote: On Tue, 2007-01-09 at 13:15 +0100, Jan Kara wrote: On Mon, Jan 08, 2007 at 11:18:52AM -0800, Andrew Morton wrote: On Sun, 7 Jan 2007 23:12:53 -0500 Josef 'Jeff' Sipek [EMAIL PROTECTED] wrote: snip Any

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-09 Thread Erez Zadok
In message [EMAIL PROTECTED], Trond Myklebust writes: I'm saying that at the very least it should not Oops in these situations. As to whether or not they are something you want to handle more gracefully, that is up to you, but Oopses are definitely a showstopper. Trond I totally agree:

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-09 Thread Erez Zadok
In message [EMAIL PROTECTED], Jan Kara writes: In message [EMAIL PROTECTED], Andrew Morton writes: On Sun, 7 Jan 2007 23:12:53 -0500 Josef 'Jeff' Sipek [EMAIL PROTECTED] wrote: +Modifying a Unionfs branch directly, while the union is mounted, is +currently unsupported.

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-09 Thread Erez Zadok
In message [EMAIL PROTECTED], Christoph Hellwig writes: On Mon, Jan 08, 2007 at 07:03:35PM -0500, Erez Zadok wrote: However, I must caution that a file system like ecryptfs is very different from Unionfs, the latter being a fan-out file system---and both have very different goals. The

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-09 Thread Jan Engelhardt
On Jan 9 2007 11:41, Shaya Potter wrote: Again, what about fibre channel support? Imagine I have multiple blades connected to a SAN. For whatever reason I format the san w/ ext3 (I've actually done this when we didn't need sharing, just needed a huge disk, for instance for doing benchmarks

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-08 Thread Shaya Potter
On Tue, 2007-01-09 at 02:26 +0100, Jan Engelhardt wrote: > On Jan 8 2007 19:33, Josef Sipek wrote: > >On Tue, Jan 09, 2007 at 01:19:48AM +0100, Giuseppe Bilotta wrote: > >> As a simple user without much knowledge of kernel internals, much less > >> so filesystems, couldn't something based on the

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-08 Thread Jan Engelhardt
On Jan 8 2007 19:33, Josef Sipek wrote: >On Tue, Jan 09, 2007 at 01:19:48AM +0100, Giuseppe Bilotta wrote: >> As a simple user without much knowledge of kernel internals, much less >> so filesystems, couldn't something based on the same principle of >> lsof+fam be used to handle these situations?

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-08 Thread Josef Sipek
On Tue, Jan 09, 2007 at 01:19:48AM +0100, Giuseppe Bilotta wrote: > As a simple user without much knowledge of kernel internals, much less > so filesystems, couldn't something based on the same principle of > lsof+fam be used to handle these situations? Using inotify has been suggested before.

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-08 Thread Giuseppe Bilotta
On Mon, 8 Jan 2007 15:51:31 -0500, Erez Zadok wrote: > Now, we've discussed a number of possible solutions. Thanks to suggestions > we got at OLS, we discussed a way to hide the lower namespace, or make it > readonly, using existing kernel facilities. But my understanding is that > even it'd

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-08 Thread Erez Zadok
In message <[EMAIL PROTECTED]>, Andrew Morton writes: > On Mon, 08 Jan 2007 16:30:48 -0500 > Shaya Potter <[EMAIL PROTECTED]> wrote: > > Well yes. So the top-level question is "is this the correct way of doing > unionisation?". > I suspect not, in which case unionfs is at best a stopgap until

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-08 Thread Josef Sipek
On Mon, Jan 08, 2007 at 05:00:18PM -0600, Michael Halcrow wrote: > On Mon, Jan 08, 2007 at 03:51:31PM -0500, Erez Zadok wrote: > > BTW, this is a problem with all stackable file systems, including > > ecryptfs. To be fair, our Unionfs users have come up against this > > problem, usually for the

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-08 Thread Jan Engelhardt
On Jan 8 2007 14:02, Andrew Morton wrote: >Shaya Potter <[EMAIL PROTECTED]> wrote: >> >> the difference is bind mounts are a vfs construct, while unionfs is a >> file system. > >Well yes. So the top-level question is "is this the correct way of doing >unionisation?". >I suspect not, in which

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-08 Thread Josef Sipek
On Mon, Jan 08, 2007 at 02:02:24PM -0800, Andrew Morton wrote: > On Mon, 08 Jan 2007 16:30:48 -0500 > Shaya Potter <[EMAIL PROTECTED]> wrote: > > > On Mon, 2007-01-08 at 13:19 -0800, Andrew Morton wrote: > > > On Mon, 8 Jan 2007 14:43:39 -0500 (EST) Shaya Potter <[EMAIL PROTECTED]> > > > wrote:

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-08 Thread Josef Sipek
On Mon, Jan 08, 2007 at 01:19:57PM -0800, Andrew Morton wrote: ... > If it's not in the changelog or the documentation, it doesn't exist. Good point. I'll add it for next time. > > It's the same thing as modifying a block > > device while a file system is using it. Now, when unionfs gets

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-08 Thread Josef Sipek
On Mon, Jan 08, 2007 at 11:18:52AM -0800, Andrew Morton wrote: > On Sun, 7 Jan 2007 23:12:53 -0500 > "Josef 'Jeff' Sipek" <[EMAIL PROTECTED]> wrote: > > > +Modifying a Unionfs branch directly, while the union is mounted, is > > +currently unsupported. > > Does this mean that if I have /a/b/ and

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-08 Thread Michael Halcrow
On Mon, Jan 08, 2007 at 03:51:31PM -0500, Erez Zadok wrote: > BTW, this is a problem with all stackable file systems, including > ecryptfs. To be fair, our Unionfs users have come up against this > problem, usually for the first time they use Unionfs :-). I suspect that the only reason why this

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-08 Thread Shaya Potter
Is there vendor interest in unionfs? MANY live cds seem to use it. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-08 Thread Andrew Morton
On Mon, 08 Jan 2007 16:30:48 -0500 Shaya Potter <[EMAIL PROTECTED]> wrote: > On Mon, 2007-01-08 at 13:19 -0800, Andrew Morton wrote: > > On Mon, 8 Jan 2007 14:43:39 -0500 (EST) Shaya Potter <[EMAIL PROTECTED]> > > wrote: > > > It's the same thing as modifying a block > > > device while a file

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-08 Thread Jan Engelhardt
On Jan 8 2007 15:51, Erez Zadok wrote: > >BTW, this is a problem with all stackable file systems, including >ecryptfs. To be fair, our Unionfs users have come up against this >problem, usually for the first time they use Unionfs :-). Then we >tell not to do that, but that if they have to, to run

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-08 Thread Shaya Potter
On Mon, 2007-01-08 at 13:19 -0800, Andrew Morton wrote: > On Mon, 8 Jan 2007 14:43:39 -0500 (EST) Shaya Potter <[EMAIL PROTECTED]> > wrote: > > It's the same thing as modifying a block > > device while a file system is using it. Now, when unionfs gets confused, > > it shouldn't oops, but

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-08 Thread Shaya Potter
On Mon, 2007-01-08 at 21:24 +0100, Jan Engelhardt wrote: > On Jan 8 2007 14:43, Shaya Potter wrote: > > On Mon, 8 Jan 2007, Andrew Morton wrote: > >> On Sun, 7 Jan 2007 23:12:53 -0500 > >> "Josef 'Jeff' Sipek" <[EMAIL PROTECTED]> wrote: > >> > >> > +Modifying a Unionfs branch directly, while the

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-08 Thread Andrew Morton
On Mon, 8 Jan 2007 14:43:39 -0500 (EST) Shaya Potter <[EMAIL PROTECTED]> wrote: > On Mon, 8 Jan 2007, Andrew Morton wrote: > > > On Sun, 7 Jan 2007 23:12:53 -0500 > > "Josef 'Jeff' Sipek" <[EMAIL PROTECTED]> wrote: > > > >> +Modifying a Unionfs branch directly, while the union is mounted, is >

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-08 Thread Erez Zadok
In message <[EMAIL PROTECTED]>, Andrew Morton writes: > On Sun, 7 Jan 2007 23:12:53 -0500 > "Josef 'Jeff' Sipek" <[EMAIL PROTECTED]> wrote: > > > +Modifying a Unionfs branch directly, while the union is mounted, is > > +currently unsupported. > > Does this mean that if I have /a/b/ and /c/d/

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-08 Thread Jan Engelhardt
On Jan 8 2007 14:43, Shaya Potter wrote: > On Mon, 8 Jan 2007, Andrew Morton wrote: >> On Sun, 7 Jan 2007 23:12:53 -0500 >> "Josef 'Jeff' Sipek" <[EMAIL PROTECTED]> wrote: >> >> > +Modifying a Unionfs branch directly, while the union is >> > +mounted, is currently unsupported. >> >> Does this

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-08 Thread Shaya Potter
On Mon, 8 Jan 2007, Andrew Morton wrote: On Sun, 7 Jan 2007 23:12:53 -0500 "Josef 'Jeff' Sipek" <[EMAIL PROTECTED]> wrote: +Modifying a Unionfs branch directly, while the union is mounted, is +currently unsupported. Does this mean that if I have /a/b/ and /c/d/ unionised under /mnt/union,

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-08 Thread Andrew Morton
On Sun, 7 Jan 2007 23:12:53 -0500 "Josef 'Jeff' Sipek" <[EMAIL PROTECTED]> wrote: > +Modifying a Unionfs branch directly, while the union is mounted, is > +currently unsupported. Does this mean that if I have /a/b/ and /c/d/ unionised under /mnt/union, I am not allowed to alter anything under

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-08 Thread Andrew Morton
On Sun, 7 Jan 2007 23:12:53 -0500 Josef 'Jeff' Sipek [EMAIL PROTECTED] wrote: +Modifying a Unionfs branch directly, while the union is mounted, is +currently unsupported. Does this mean that if I have /a/b/ and /c/d/ unionised under /mnt/union, I am not allowed to alter anything under /a/b/

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-08 Thread Shaya Potter
On Mon, 8 Jan 2007, Andrew Morton wrote: On Sun, 7 Jan 2007 23:12:53 -0500 Josef 'Jeff' Sipek [EMAIL PROTECTED] wrote: +Modifying a Unionfs branch directly, while the union is mounted, is +currently unsupported. Does this mean that if I have /a/b/ and /c/d/ unionised under /mnt/union, I am

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-08 Thread Jan Engelhardt
On Jan 8 2007 14:43, Shaya Potter wrote: On Mon, 8 Jan 2007, Andrew Morton wrote: On Sun, 7 Jan 2007 23:12:53 -0500 Josef 'Jeff' Sipek [EMAIL PROTECTED] wrote: +Modifying a Unionfs branch directly, while the union is +mounted, is currently unsupported. Does this mean that if I have

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-08 Thread Erez Zadok
In message [EMAIL PROTECTED], Andrew Morton writes: On Sun, 7 Jan 2007 23:12:53 -0500 Josef 'Jeff' Sipek [EMAIL PROTECTED] wrote: +Modifying a Unionfs branch directly, while the union is mounted, is +currently unsupported. Does this mean that if I have /a/b/ and /c/d/ unionised under

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-08 Thread Andrew Morton
On Mon, 8 Jan 2007 14:43:39 -0500 (EST) Shaya Potter [EMAIL PROTECTED] wrote: On Mon, 8 Jan 2007, Andrew Morton wrote: On Sun, 7 Jan 2007 23:12:53 -0500 Josef 'Jeff' Sipek [EMAIL PROTECTED] wrote: +Modifying a Unionfs branch directly, while the union is mounted, is +currently

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-08 Thread Shaya Potter
On Mon, 2007-01-08 at 21:24 +0100, Jan Engelhardt wrote: On Jan 8 2007 14:43, Shaya Potter wrote: On Mon, 8 Jan 2007, Andrew Morton wrote: On Sun, 7 Jan 2007 23:12:53 -0500 Josef 'Jeff' Sipek [EMAIL PROTECTED] wrote: +Modifying a Unionfs branch directly, while the union is

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-08 Thread Shaya Potter
On Mon, 2007-01-08 at 13:19 -0800, Andrew Morton wrote: On Mon, 8 Jan 2007 14:43:39 -0500 (EST) Shaya Potter [EMAIL PROTECTED] wrote: It's the same thing as modifying a block device while a file system is using it. Now, when unionfs gets confused, it shouldn't oops, but would one

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-08 Thread Jan Engelhardt
On Jan 8 2007 15:51, Erez Zadok wrote: BTW, this is a problem with all stackable file systems, including ecryptfs. To be fair, our Unionfs users have come up against this problem, usually for the first time they use Unionfs :-). Then we tell not to do that, but that if they have to, to run

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-08 Thread Andrew Morton
On Mon, 08 Jan 2007 16:30:48 -0500 Shaya Potter [EMAIL PROTECTED] wrote: On Mon, 2007-01-08 at 13:19 -0800, Andrew Morton wrote: On Mon, 8 Jan 2007 14:43:39 -0500 (EST) Shaya Potter [EMAIL PROTECTED] wrote: It's the same thing as modifying a block device while a file system is using

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-08 Thread Shaya Potter
Is there vendor interest in unionfs? MANY live cds seem to use it. - To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-08 Thread Michael Halcrow
On Mon, Jan 08, 2007 at 03:51:31PM -0500, Erez Zadok wrote: BTW, this is a problem with all stackable file systems, including ecryptfs. To be fair, our Unionfs users have come up against this problem, usually for the first time they use Unionfs :-). I suspect that the only reason why this has

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-08 Thread Josef Sipek
On Mon, Jan 08, 2007 at 11:18:52AM -0800, Andrew Morton wrote: On Sun, 7 Jan 2007 23:12:53 -0500 Josef 'Jeff' Sipek [EMAIL PROTECTED] wrote: +Modifying a Unionfs branch directly, while the union is mounted, is +currently unsupported. Does this mean that if I have /a/b/ and /c/d/

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-08 Thread Josef Sipek
On Mon, Jan 08, 2007 at 01:19:57PM -0800, Andrew Morton wrote: ... If it's not in the changelog or the documentation, it doesn't exist. Good point. I'll add it for next time. It's the same thing as modifying a block device while a file system is using it. Now, when unionfs gets

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-08 Thread Josef Sipek
On Mon, Jan 08, 2007 at 02:02:24PM -0800, Andrew Morton wrote: On Mon, 08 Jan 2007 16:30:48 -0500 Shaya Potter [EMAIL PROTECTED] wrote: On Mon, 2007-01-08 at 13:19 -0800, Andrew Morton wrote: On Mon, 8 Jan 2007 14:43:39 -0500 (EST) Shaya Potter [EMAIL PROTECTED] wrote: It's the

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-08 Thread Jan Engelhardt
On Jan 8 2007 14:02, Andrew Morton wrote: Shaya Potter [EMAIL PROTECTED] wrote: the difference is bind mounts are a vfs construct, while unionfs is a file system. Well yes. So the top-level question is is this the correct way of doing unionisation?. I suspect not, in which case unionfs is

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-08 Thread Josef Sipek
On Mon, Jan 08, 2007 at 05:00:18PM -0600, Michael Halcrow wrote: On Mon, Jan 08, 2007 at 03:51:31PM -0500, Erez Zadok wrote: BTW, this is a problem with all stackable file systems, including ecryptfs. To be fair, our Unionfs users have come up against this problem, usually for the first

Re: [PATCH 01/24] Unionfs: Documentation

2007-01-08 Thread Erez Zadok
In message [EMAIL PROTECTED], Andrew Morton writes: On Mon, 08 Jan 2007 16:30:48 -0500 Shaya Potter [EMAIL PROTECTED] wrote: Well yes. So the top-level question is is this the correct way of doing unionisation?. I suspect not, in which case unionfs is at best a stopgap until someone

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