32-bit ioctl uses these rather than the regular FS_IOC_* versions. They can be
handled in btrfs using the same code. Without this, 32-bit {ch,ls}attr fail.
Signed-off-by: Luke Dashjr <[email protected]>
---
fs/btrfs/ioctl.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 1c22c65..31af093 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -5225,10 +5225,13 @@ long btrfs_ioctl(struct file *file, unsigned int
switch (cmd) {
case FS_IOC_GETFLAGS:
+ case FS_IOC32_GETFLAGS:
return btrfs_ioctl_getflags(file, argp);
case FS_IOC_SETFLAGS:
+ case FS_IOC32_SETFLAGS:
return btrfs_ioctl_setflags(file, argp);
case FS_IOC_GETVERSION:
+ case FS_IOC32_GETVERSION:
return btrfs_ioctl_getversion(file, argp);
case FITRIM:
return btrfs_ioctl_fitrim(file, argp);
--
2.0.5
On Wed, May 13, 2015 at 05:15:26PM +0000, Luke Dashjr wrote:
> 32-bit ioctl uses these rather than the regular FS_IOC_* versions. They can be
> handled in btrfs using the same code. Without this, 32-bit {ch,ls}attr fail.
>
> Signed-off-by: Luke Dashjr <[email protected]>
> ---
> fs/btrfs/ioctl.c | 3 +++
> 1 file changed, 3 insertions(+)
<formletter>
This is not the correct way to submit patches for inclusion in the
stable kernel tree. Please read Documentation/stable_kernel_rules.txt
for how to do this properly.
</formletter>
On Wed, May 13, 2015 at 05:15:26PM +0000, Luke Dashjr wrote:
> 32-bit ioctl uses these rather than the regular FS_IOC_* versions. They can be
> handled in btrfs using the same code. Without this, 32-bit {ch,ls}attr fail.
Yes, but this has to be implemented in another way. See eg.
https://git.kernel.org/linus/e9750824114ff
On Thursday, May 14, 2015 2:06:17 PM David Sterba wrote:
> On Wed, May 13, 2015 at 05:15:26PM +0000, Luke Dashjr wrote:
> > 32-bit ioctl uses these rather than the regular FS_IOC_* versions. They
> > can be handled in btrfs using the same code. Without this, 32-bit
> > {ch,ls}attr fail.
>
> Yes, but this has to be implemented in another way. See eg.
> https://git.kernel.org/linus/e9750824114ff
I don't see what is different with that implementation. All f2fs_compat_ioctl
does is change cmd to the plain-IOC equivalent and call f2fs_ioctl with the
same arg (compat_ptr merely causes a cast to void* and back, which AFAIK is a
noop on 64-bit?). Am I missing something? I could try to just imitate it, but
I'd rather know what is significant/going on to ensure I don't waste your time
with code I don't even properly understand myself.
Perhaps by coincidence, the patch does at least in practice work (although at
least `btrfs send` appears to be broken still, and I'm at a loss for how to
approach fixing that).
Luke
On Thu, May 14, 2015 at 04:27:54PM +0000, Luke Dashjr wrote:
> On Thursday, May 14, 2015 2:06:17 PM David Sterba wrote:
> > On Wed, May 13, 2015 at 05:15:26PM +0000, Luke Dashjr wrote:
> > > 32-bit ioctl uses these rather than the regular FS_IOC_* versions. They
> > > can be handled in btrfs using the same code. Without this, 32-bit
> > > {ch,ls}attr fail.
> >
> > Yes, but this has to be implemented in another way. See eg.
> > https://git.kernel.org/linus/e9750824114ff
>
> I don't see what is different with that implementation. All f2fs_compat_ioctl
> does is change cmd to the plain-IOC equivalent and call f2fs_ioctl with the
> same arg (compat_ptr merely causes a cast to void* and back, which AFAIK is a
> noop on 64-bit?). Am I missing something?
No, that's the idea. Add new calback for compat_ioctl, put it under
#ifdef CONFIG_COMPAT and do the same number switch.
> I could try to just imitate it, but
> I'd rather know what is significant/going on to ensure I don't waste your time
> with code I don't even properly understand myself.
>
> Perhaps by coincidence, the patch does at least in practice work (although at
> least `btrfs send` appears to be broken still, and I'm at a loss for how to
> approach fixing that).
The 'receive' 32bit/64bit was broken due to size difference in the ioctl
structure that led to different ioctl. This is transparently fixed, see
BTRFS_IOC_SET_RECEIVED_SUBVOL_32 at the top of ioctl.c.
In what way is SEND broken? There are only u64/s64 members in
btrfs_ioctl_send_args, I don't see how this could break on 32/64
userspace/kernel.
On Friday, May 15, 2015 11:19:22 AM David Sterba wrote:
> On Thu, May 14, 2015 at 04:27:54PM +0000, Luke Dashjr wrote:
> > On Thursday, May 14, 2015 2:06:17 PM David Sterba wrote:
> > > On Wed, May 13, 2015 at 05:15:26PM +0000, Luke Dashjr wrote:
> > > > 32-bit ioctl uses these rather than the regular FS_IOC_* versions.
> > > > They can be handled in btrfs using the same code. Without this,
> > > > 32-bit {ch,ls}attr fail.
> > >
> > > Yes, but this has to be implemented in another way. See eg.
> > > https://git.kernel.org/linus/e9750824114ff
> >
> > I don't see what is different with that implementation. All
> > f2fs_compat_ioctl does is change cmd to the plain-IOC equivalent and
> > call f2fs_ioctl with the same arg (compat_ptr merely causes a cast to
> > void* and back, which AFAIK is a noop on 64-bit?). Am I missing
> > something?
>
> No, that's the idea. Add new calback for compat_ioctl, put it under
> #ifdef CONFIG_COMPAT and do the same number switch.
The idea is to wrap it in a way that doesn't actually change any of the logic?
I'm not sure I understand still :(
> > I could try to just imitate it, but
> > I'd rather know what is significant/going on to ensure I don't waste your
> > time with code I don't even properly understand myself.
> >
> > Perhaps by coincidence, the patch does at least in practice work
> > (although at least `btrfs send` appears to be broken still, and I'm at a
> > loss for how to approach fixing that).
>
> The 'receive' 32bit/64bit was broken due to size difference in the ioctl
> structure that led to different ioctl. This is transparently fixed, see
> BTRFS_IOC_SET_RECEIVED_SUBVOL_32 at the top of ioctl.c.
>
> In what way is SEND broken? There are only u64/s64 members in
> btrfs_ioctl_send_args, I don't see how this could break on 32/64
> userspace/kernel.
# btrfs send -p home/initial/ home/20150514_1431573370/
At subvol home/20150514_1431573370/
ERROR: send ioctl failed with -25: Inappropriate ioctl for device
But I am stuck on 3.14.41 due to Linux being unstable in newer versions[1], so
maybe this is unrelated to 32-bit and already fixed in 4.0?
Luke
1. https://bugzilla.kernel.org/show_bug.cgi?id=87891