Patch "Fix cifs_uniqueid_to_ino_t() function for s390x" has been added to the 4.4-stable tree

This is a note to let you know that I've just added the patch titled

    Fix cifs_uniqueid_to_ino_t() function for s390x

to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:

     fix-cifs_uniqueid_to_ino_t-function-for-s390x.patch

and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Yadan Fan <[email protected]>
Date: Mon, 29 Feb 2016 14:44:57 +0800
Subject: Fix cifs_uniqueid_to_ino_t() function for s390x

From: Yadan Fan <[email protected]>

commit 1ee9f4bd1a97026a7b2d7ae9f1f74b45680d0003 upstream.

This issue is caused by commit 02323db17e3a7 ("cifs: fix cifs_uniqueid_to_ino_t not to ever return 0"), when BITS_PER_LONG is 64 on s390x, the corresponding cifs_uniqueid_to_ino_t() function will cast 64-bit fileid to 32-bit by using (ino_t)fileid, because ino_t (typdefed __kernel_ino_t) is int type.

It's defined in arch/s390/include/uapi/asm/posix_types.h

    #ifndef __s390x__

    typedef unsigned long   __kernel_ino_t;
    ...
    #else /* __s390x__ */

    typedef unsigned int    __kernel_ino_t;

So the #ifdef condition is wrong for s390x, we can just still use one cifs_uniqueid_to_ino_t() function with comparing sizeof(ino_t) and sizeof(u64) to choose the correct execution accordingly.

---
 fs/cifs/cifsfs.h |   12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

@@ -31,19 +31,15 @@
  * so that it will fit. We use hash_64 to convert the value to 31 bits, and
  * then add 1, to ensure that we don't end up with a 0 as the value.
  */
-#if BITS_PER_LONG == 64
 static inline ino_t
 cifs_uniqueid_to_ino_t(u64 fileid)
 {
+	if ((sizeof(ino_t)) < (sizeof(u64)))
+		return (ino_t)hash_64(fileid, (sizeof(ino_t) * 8) - 1) + 1;
+
 	return (ino_t)fileid;
+
 }
-#else
-static inline ino_t
-cifs_uniqueid_to_ino_t(u64 fileid)
-{
-	return (ino_t)hash_64(fileid, (sizeof(ino_t) * 8) - 1) + 1;
-}
-#endif
 
 extern struct file_system_type cifs_fs_type;
 extern const struct address_space_operations cifs_addr_ops;

Patches currently in stable-queue which might be from [email protected] are

queue-4.4/fix-cifs_uniqueid_to_ino_t-function-for-s390x.patch