Re: overlayfs: "filesystem of lowerdir is not supported" on cdrom

2014-10-28 Thread Tim Tassonis
On 10/28/2014 11:54 PM, Al Viro wrote:
> On Tue, Oct 28, 2014 at 09:13:13PM +, Al Viro wrote:
> 
>>
>> We probably ought to split the normal (case-sensitive, no joliet shite) case
>> out and leave it with NULL ->s_d_op, but that'll need to be done carefully,
>> or isofs_cmp() will blow up on us.
> 
> See if vfs.git#for-linus works for you.
> 

Yes, works for me! Could mount the overlayfs, remove a file, add a file
and modify a file. Not the definive stress-test I guess, but it's a start...

Took only the following two commits:

f643ff550afbc82a2bc7026f4a6d64427e4fbc9

5b71ecfa78271d5c576f17156ed8a53981c1ecb

Kind regards
Tim

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Re: overlayfs: "filesystem of lowerdir is not supported" on cdrom

2014-10-28 Thread Al Viro
On Tue, Oct 28, 2014 at 09:13:13PM +, Al Viro wrote:

> Documentation is wildly over-optimistic.  You are trying to use something
> with non-trivial ->d_hash and ->d_compare as lower layer.
> 
> What should happen if you ask to mount an image with joliet extensions and
> ask to create foo.txt when foo.txt is there?  From the isofs POV those
> are the same; for overlayfs they are not (it's using default ->d_hash
> and ->d_compare).
> 
> We probably ought to split the normal (case-sensitive, no joliet shite) case
> out and leave it with NULL ->s_d_op, but that'll need to be done carefully,
> or isofs_cmp() will blow up on us.

See if vfs.git#for-linus works for you.
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Re: overlayfs: "filesystem of lowerdir is not supported" on cdrom

2014-10-28 Thread Al Viro
On Tue, Oct 28, 2014 at 07:10:36PM +0100, Tim Tassonis wrote:
> Hi
> 
> Just installed 3.18-rc2 and tried to test the overlayfs stuff:
> 
> $ mkdir /ovtmp
> $ mount -t tmpfs tmpfs /ovtmp/
> $ mkdir /ovtmp/work
> $ mkdir /ovtmp/upper
> $ mkdir /cdrw
> $ mount /dev/sr0 /mnt
> $ mount |egrep "ovtmp|sr0"
> 
> /dev/sr0 on /mnt type iso9660 (ro,relatime)
> tmpfs on /ovtmp type tmpfs (rw,relatime)
> 
> $ mount -t overlayfs overlayfs \
>  -olowerdir=/mnt,upperdir=/ovtmp/upper,workdir=/ovtmp/work /cdrw

> [ 3266.793218] overlayfs: filesystem of lowerdir is not supported
> 
> However, the doc in Documentation/filesystems/overlayfs.txt states:
> 
> "The lower filesystem can be any filesystem supported by Linux and does
> not need to be writable.  The lower filesystem can even be another
> overlayfs.  The upper filesystem will normally be writable and if it
> is it must support the creation of trusted.* extended attributes, and
> must provide valid d_type in readdir responses, so NFS is not suitable."
> 
> So: Is the documentation wrong, the error message in dmesg wrong, or
> have missed something completely?

Documentation is wildly over-optimistic.  You are trying to use something
with non-trivial ->d_hash and ->d_compare as lower layer.

What should happen if you ask to mount an image with joliet extensions and
ask to create foo.txt when foo.txt is there?  From the isofs POV those
are the same; for overlayfs they are not (it's using default ->d_hash
and ->d_compare).

We probably ought to split the normal (case-sensitive, no joliet shite) case
out and leave it with NULL ->s_d_op, but that'll need to be done carefully,
or isofs_cmp() will blow up on us.
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overlayfs: "filesystem of lowerdir is not supported" on cdrom

2014-10-28 Thread Tim Tassonis
Hi

Just installed 3.18-rc2 and tried to test the overlayfs stuff:

$ mkdir /ovtmp
$ mount -t tmpfs tmpfs /ovtmp/
$ mkdir /ovtmp/work
$ mkdir /ovtmp/upper
$ mkdir /cdrw
$ mount /dev/sr0 /mnt
$ mount |egrep "ovtmp|sr0"

/dev/sr0 on /mnt type iso9660 (ro,relatime)
tmpfs on /ovtmp type tmpfs (rw,relatime)

$ mount -t overlayfs overlayfs \
 -olowerdir=/mnt,upperdir=/ovtmp/upper,workdir=/ovtmp/work /cdrw

mount: wrong fs type, bad option, bad superblock on overlayfs,
   missing codepage or helper program, or other error

   In some cases useful info is found in syslog - try
   dmesg | tail or so.

$ dmesg |tail

[ 3266.793218] overlayfs: filesystem of lowerdir is not supported

However, the doc in Documentation/filesystems/overlayfs.txt states:

"The lower filesystem can be any filesystem supported by Linux and does
not need to be writable.  The lower filesystem can even be another
overlayfs.  The upper filesystem will normally be writable and if it
is it must support the creation of trusted.* extended attributes, and
must provide valid d_type in readdir responses, so NFS is not suitable."

So: Is the documentation wrong, the error message in dmesg wrong, or
have missed something completely?


Kind regards
Tim

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overlayfs: filesystem of lowerdir is not supported on cdrom

2014-10-28 Thread Tim Tassonis
Hi

Just installed 3.18-rc2 and tried to test the overlayfs stuff:

$ mkdir /ovtmp
$ mount -t tmpfs tmpfs /ovtmp/
$ mkdir /ovtmp/work
$ mkdir /ovtmp/upper
$ mkdir /cdrw
$ mount /dev/sr0 /mnt
$ mount |egrep ovtmp|sr0

/dev/sr0 on /mnt type iso9660 (ro,relatime)
tmpfs on /ovtmp type tmpfs (rw,relatime)

$ mount -t overlayfs overlayfs \
 -olowerdir=/mnt,upperdir=/ovtmp/upper,workdir=/ovtmp/work /cdrw

mount: wrong fs type, bad option, bad superblock on overlayfs,
   missing codepage or helper program, or other error

   In some cases useful info is found in syslog - try
   dmesg | tail or so.

$ dmesg |tail

[ 3266.793218] overlayfs: filesystem of lowerdir is not supported

However, the doc in Documentation/filesystems/overlayfs.txt states:

The lower filesystem can be any filesystem supported by Linux and does
not need to be writable.  The lower filesystem can even be another
overlayfs.  The upper filesystem will normally be writable and if it
is it must support the creation of trusted.* extended attributes, and
must provide valid d_type in readdir responses, so NFS is not suitable.

So: Is the documentation wrong, the error message in dmesg wrong, or
have missed something completely?


Kind regards
Tim

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Re: overlayfs: filesystem of lowerdir is not supported on cdrom

2014-10-28 Thread Al Viro
On Tue, Oct 28, 2014 at 07:10:36PM +0100, Tim Tassonis wrote:
 Hi
 
 Just installed 3.18-rc2 and tried to test the overlayfs stuff:
 
 $ mkdir /ovtmp
 $ mount -t tmpfs tmpfs /ovtmp/
 $ mkdir /ovtmp/work
 $ mkdir /ovtmp/upper
 $ mkdir /cdrw
 $ mount /dev/sr0 /mnt
 $ mount |egrep ovtmp|sr0
 
 /dev/sr0 on /mnt type iso9660 (ro,relatime)
 tmpfs on /ovtmp type tmpfs (rw,relatime)
 
 $ mount -t overlayfs overlayfs \
  -olowerdir=/mnt,upperdir=/ovtmp/upper,workdir=/ovtmp/work /cdrw

 [ 3266.793218] overlayfs: filesystem of lowerdir is not supported
 
 However, the doc in Documentation/filesystems/overlayfs.txt states:
 
 The lower filesystem can be any filesystem supported by Linux and does
 not need to be writable.  The lower filesystem can even be another
 overlayfs.  The upper filesystem will normally be writable and if it
 is it must support the creation of trusted.* extended attributes, and
 must provide valid d_type in readdir responses, so NFS is not suitable.
 
 So: Is the documentation wrong, the error message in dmesg wrong, or
 have missed something completely?

Documentation is wildly over-optimistic.  You are trying to use something
with non-trivial -d_hash and -d_compare as lower layer.

What should happen if you ask to mount an image with joliet extensions and
ask to create foo.txt when foo.txt is there?  From the isofs POV those
are the same; for overlayfs they are not (it's using default -d_hash
and -d_compare).

We probably ought to split the normal (case-sensitive, no joliet shite) case
out and leave it with NULL -s_d_op, but that'll need to be done carefully,
or isofs_cmp() will blow up on us.
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Re: overlayfs: filesystem of lowerdir is not supported on cdrom

2014-10-28 Thread Al Viro
On Tue, Oct 28, 2014 at 09:13:13PM +, Al Viro wrote:

 Documentation is wildly over-optimistic.  You are trying to use something
 with non-trivial -d_hash and -d_compare as lower layer.
 
 What should happen if you ask to mount an image with joliet extensions and
 ask to create foo.txt when foo.txt is there?  From the isofs POV those
 are the same; for overlayfs they are not (it's using default -d_hash
 and -d_compare).
 
 We probably ought to split the normal (case-sensitive, no joliet shite) case
 out and leave it with NULL -s_d_op, but that'll need to be done carefully,
 or isofs_cmp() will blow up on us.

See if vfs.git#for-linus works for you.
--
To unsubscribe from this list: send the line unsubscribe linux-kernel in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/


Re: overlayfs: filesystem of lowerdir is not supported on cdrom

2014-10-28 Thread Tim Tassonis
On 10/28/2014 11:54 PM, Al Viro wrote:
 On Tue, Oct 28, 2014 at 09:13:13PM +, Al Viro wrote:
 

 We probably ought to split the normal (case-sensitive, no joliet shite) case
 out and leave it with NULL -s_d_op, but that'll need to be done carefully,
 or isofs_cmp() will blow up on us.
 
 See if vfs.git#for-linus works for you.
 

Yes, works for me! Could mount the overlayfs, remove a file, add a file
and modify a file. Not the definive stress-test I guess, but it's a start...

Took only the following two commits:

f643ff550afbc82a2bc7026f4a6d64427e4fbc9

5b71ecfa78271d5c576f17156ed8a53981c1ecb

Kind regards
Tim

--
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the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/