path: root/fs/cifs/cifsfs.h
diff options
authorJeff Layton <jlayton@poochiereds.net>2014-05-02 13:50:02 -0400
committerSteve French <smfrench@gmail.com>2014-05-21 10:18:04 -0700
commit02323db17e3a73dd335690b7b1a2392912b05513 (patch)
tree24a6b832587ad960bd0da9af7a3f22e7826135e9 /fs/cifs/cifsfs.h
parentLinux 3.15-rc6 (diff)
cifs: fix cifs_uniqueid_to_ino_t not to ever return 0
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>
Diffstat (limited to 'fs/cifs/cifsfs.h')
1 files changed, 13 insertions, 5 deletions
diff --git a/fs/cifs/cifsfs.h b/fs/cifs/cifsfs.h
index 26a754f49ba1..89eab9a55f18 100644
--- a/fs/cifs/cifsfs.h
+++ b/fs/cifs/cifsfs.h
@@ -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;
+static inline ino_t
+cifs_uniqueid_to_ino_t(u64 fileid)
+ return (ino_t)hash_64(fileid, (sizeof(ino_t) * 8) - 1) + 1;
extern struct file_system_type cifs_fs_type;
extern const struct address_space_operations cifs_addr_ops;