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 bo
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 b
> 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 qu
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
sin
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 h
> 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
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 :)
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
> 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
>
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
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 e
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
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.
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
> > > > +curr
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 ag
> 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:
> > > > >
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
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.
Rem
> 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 t
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 partic
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:
> > > >
> >
> >
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 files
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
> > > > sile
> 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/
> 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
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
> > fil
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 e
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
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
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
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 seeme
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 sa
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?
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. Tha
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 wor
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 s
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 fi
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 cas
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:
>
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 conf
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
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 h
Is there vendor interest in unionfs?
MANY live cds seem to use it.
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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 s
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
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
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
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
> >
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/ uni
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 m
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
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
From: Josef "Jeff" Sipek <[EMAIL PROTECTED]>
This patch contains documentation for Unionfs. You will find several files
outlining basic unification concepts and rename semantics.
Signed-off-by: Josef "Jeff" Sipek <[EMAIL PROTECTED]>
Signed-off-by: David Quigley <[EMAIL PROTECTED]>
Signed-off-by:
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