re: btrfs: allow mounting btrfs subvolumes with different ro/rw options

re: btrfs: allow mounting btrfs subvolumes with different ro/rw options

[Dan Carpenter]

Hello Harald Hoyer,

The patch 0723a0473fb4: "btrfs: allow mounting btrfs subvolumes with
different ro/rw options" from Nov 19, 2013, leads to the following
static checker warning:

	fs/btrfs/super.c:1194 mount_subvol()
	warn: 'newargs' was already freed.

fs/btrfs/super.c
  1177  static struct dentry *mount_subvol(const char *subvol_name, int flags,
  1178                                     const char *device_name, char *data)
  1179  {
  1180          struct dentry *root;
  1181          struct vfsmount *mnt;
  1182          char *newargs;
  1183  
  1184          newargs = setup_root_args(data);
  1185          if (!newargs)
  1186                  return ERR_PTR(-ENOMEM);
  1187          mnt = vfs_kern_mount(&btrfs_fs_type, flags, device_name,
  1188                               newargs);
  1189          kfree(newargs);
                      ^^^^^^^
Freed.

  1190  
  1191          if (PTR_RET(mnt) == -EBUSY) {
  1192                  if (flags & MS_RDONLY) {
  1193                          mnt = vfs_kern_mount(&btrfs_fs_type, flags & ~MS_RDONLY, device_name,
  1194                                               newargs);
                                                     ^^^^^^^
Used if you have some security stuff enabled.

  1195                  } else {
  1196                          int r;
  1197                          mnt = vfs_kern_mount(&btrfs_fs_type, flags | MS_RDONLY, device_name,
  1198                                               newargs);
                                                     ^^^^^^^
  1199                          if (IS_ERR(mnt))
  1200                                  return ERR_CAST(mnt);
  1201  
  1202                          r = btrfs_remount(mnt->mnt_sb, &flags, NULL);
  1203                          if (r < 0) {
  1204                                  /* FIXME: release vfsmount mnt ??*/
  1205                                  return ERR_PTR(r);
  1206                          }
  1207                  }
  1208          }
  1209  

Also you forgot to Sign your patch.

regards,
dan carpenter

Re: btrfs: allow mounting btrfs subvolumes with different ro/rw options

[Chris Mason]

On 04/14/2014 09:10 AM, Dan Carpenter wrote:
> Hello Harald Hoyer,
>
> The patch 0723a0473fb4: "btrfs: allow mounting btrfs subvolumes with
> different ro/rw options" from Nov 19, 2013, leads to the following
> static checker warning:

I'll fix this one up.  Harald's email has changed and I should have 
pulled the patch in long ago.

Thanks Dan!

-chris

Re: btrfs: allow mounting btrfs subvolumes with different ro/rw options

[David Sterba]

On Mon, Apr 14, 2014 at 09:39:02AM -0400, Chris Mason wrote:
> 
> 
> On 04/14/2014 09:10 AM, Dan Carpenter wrote:
> >Hello Harald Hoyer,
> >
> >The patch 0723a0473fb4: "btrfs: allow mounting btrfs subvolumes with
> >different ro/rw options" from Nov 19, 2013, leads to the following
> >static checker warning:
> 
> I'll fix this one up.  Harald's email has changed and I should have pulled
> the patch in long ago.

There are now 2 reports for that and 1 patch,
https://patchwork.kernel.org/patch/3972911/

Re: btrfs: allow mounting btrfs subvolumes with different ro/rw options

[Dan Carpenter]

On Mon, Apr 14, 2014 at 06:17:05PM +0200, David Sterba wrote:
> On Mon, Apr 14, 2014 at 09:39:02AM -0400, Chris Mason wrote:
> > 
> > 
> > On 04/14/2014 09:10 AM, Dan Carpenter wrote:
> > >Hello Harald Hoyer,
> > >
> > >The patch 0723a0473fb4: "btrfs: allow mounting btrfs subvolumes with
> > >different ro/rw options" from Nov 19, 2013, leads to the following
> > >static checker warning:
> > 
> > I'll fix this one up.  Harald's email has changed and I should have pulled
> > the patch in long ago.
> 
> There are now 2 reports for that and 1 patch,
> https://patchwork.kernel.org/patch/3972911/

It was different static checkers though.  Duplicate warnings are
unavoidable in this situation.

regards,
dan carpenter