[PATCH] btrfs: bugfix: handle FS_IOC32_{GETFLAGS,SETFLAGS,GETVERSION} in btrfs_ioctl

[PATCH] btrfs: bugfix: handle FS_IOC32_{GETFLAGS,SETFLAGS,GETVERSION} in btrfs_ioctl

[Luke Dashjr]

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 <luke-jr+git@utopios.org>
---
 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

Re: [PATCH] btrfs: bugfix: handle FS_IOC32_{GETFLAGS,SETFLAGS,GETVERSION} in btrfs_ioctl

[Greg KH]

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 <luke-jr+git@utopios.org>
> ---
>  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>

Re: [PATCH] btrfs: bugfix: handle FS_IOC32_{GETFLAGS,SETFLAGS,GETVERSION} in btrfs_ioctl

[David Sterba]

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

Re: [PATCH] btrfs: bugfix: handle FS_IOC32_{GETFLAGS,SETFLAGS,GETVERSION} in btrfs_ioctl

[Luke Dashjr]

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