Re: [PATCH 3/8] cifs: add CIFSCheckMFSymlink() as stub

[Jeff Layton <jlayton-eUNUBHrolfbYtjvyW6yDsg@public.gmane.org>]

On Thu, 05 Aug 2010 17:40:36 +0530
Suresh Jayaraman <sjayaraman-l3A5Bk7waGM@public.gmane.org> wrote:

> On 08/04/2010 08:07 PM, Jeff Layton wrote:
> > On Wed,  4 Aug 2010 16:11:44 +0200
> > Stefan Metzmacher <metze-eUNUBHrolfbYtjvyW6yDsg@public.gmane.org> wrote:
> > 
> >> Signed-off-by: Stefan Metzmacher <metze-eUNUBHrolfbYtjvyW6yDsg@public.gmane.org>
> >> ---
> >>  fs/cifs/cifsproto.h |    3 +++
> >>  fs/cifs/inode.c     |    7 +++++++
> >>  fs/cifs/link.c      |    8 ++++++++
> >>  3 files changed, 18 insertions(+), 0 deletions(-)
> >>
> >> diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
> >> index 2eaebbd..e94e095 100644
> >> --- a/fs/cifs/cifsproto.h
> >> +++ b/fs/cifs/cifsproto.h
> >> @@ -409,4 +409,7 @@ extern int CIFSSMBSetPosixACL(const int xid, struct cifsTconInfo *tcon,
> >>  extern int CIFSGetExtAttr(const int xid, struct cifsTconInfo *tcon,
> >>  			const int netfid, __u64 *pExtAttrBits, __u64 *pMask);
> >>  extern void cifs_autodisable_serverino(struct cifs_sb_info *cifs_sb);
> >> +extern int CIFSCheckMFSymlink(struct cifs_fattr *fattr,
> >> +		const unsigned char *path,
> >> +		struct cifs_sb_info *cifs_sb, int xid);
> >>  #endif			/* _CIFSPROTO_H */
> >> diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c
> >> index a15b3a9..c4121de 100644
> >> --- a/fs/cifs/inode.c
> >> +++ b/fs/cifs/inode.c
> >> @@ -661,6 +661,13 @@ int cifs_get_inode_info(struct inode **pinode,
> >>  	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_UNX_EMUL)
> >>  		cifs_sfu_mode(&fattr, full_path, cifs_sb, xid);
> >>  
> >> +	/* query for SFU type info if supported and needed */
> >> +	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS) {
> >> +		tmprc = CIFSCheckMFSymlink(&fattr, full_path, cifs_sb, xid);
> >> +		if (tmprc)
> >> +			cFYI(1, "CIFSCheckMFSymlink: %d", tmprc);
> >> +	}
> >> +
> > 
> > 		^^^^^^^^^^^^^^
> > 
> > This only seems to touch the codepath without posix extensions. What
> > about when unix extensions are enabled? The previous patch seems to
> > indicate that the behavior is that mfsymlinks are always used when that
> > mount option is used even if unix extensions are enabled. If so, then I
> > think you'll need a similar change in cifs_get_inode_info_unix.
> > 
> 
> I initially thought so. But, looking again - there is no point in
> querying for SFU type info if unix extensions are enabled..?
> 
> Thanks,
> 

I'm not sure that addresses the concern. It's very confusing, but:

    SFU != POSIX extensions

The SFU codepath goes through the "normal" cifs code
(cifs_get_inode_info). The POSIX extensions codepath goes through a
different codepath (cifs_get_inode_info_unix). Yes, all of this is
sorely in need of being cleaned up, but that's the way it works today...

Metze's patches seem to indicate that mfsymlinks and unix extensions
aren't mutually exclusive. The unix codepaths that determine inode
type and fill out inode data should be using the mfsymlink stuff too.

-- 
Jeff Layton <jlayton-eUNUBHrolfbYtjvyW6yDsg@public.gmane.org>