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cifs: fix cifs_uniqueid_to_ino_t not to ever return 0

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Currently, when the top and bottom 32-bit words are equivalent and the
host is a 32-bit arch, cifs_uniqueid_to_ino_t returns 0 as the ino_t
value. All we're doing to hash the value down to 32 bits is xor'ing the
top and bottom 32-bit words and that obviously results in 0 if they are
equivalent.

The kernel doesn't really care if it returns this value, but some
userland apps (like "ls") will ignore dirents that have a zero d_ino
value.

Change this function to use hash_64 to convert this value to a 31 bit
value and then add 1 to ensure that it doesn't ever return 0. Also,
there's no need to check the sizeof(ino_t) at runtime so create two
different cifs_uniqueid_to_ino_t functions based on whether
BITS_PER_LONG is 64 for not.

This should fix:

    https://bugzilla.kernel.org/show_bug.cgi?id=19282

Reported-by: Eric <copet_eric@emc.com>
Reported-by: <per-ola@sadata.se>
Signed-off-by: Jeff Layton <jlayton@poochiereds.net>
Signed-off-by: Steve French <smfrench@gmail.com>
This commit is contained in:
Jeff Layton 2014-05-02 13:50:02 -04:00 committed by Steve French
parent 4b660a7f5c
commit 02323db17e
1 changed files with 13 additions and 5 deletions
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18
fs/cifs/cifsfs.h
View file

@ -22,20 +22,28 @@
#ifndef _CIFSFS_H
#define _CIFSFS_H
#include <linux/hash.h>
#define ROOT_I 2
/*
* ino_t is 32-bits on 32-bit arch. We have to squash the 64-bit value down
* so that it will fit.
* 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)
{
ino_t ino = (ino_t) fileid;
if (sizeof(ino_t) < sizeof(u64))
ino ^= fileid >> (sizeof(u64)-sizeof(ino_t)) * 8;
return ino;
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;