[OpenAFS-devel] linux-and-locks-cleanup-20070202 crashes linux kernels older than 2.6.17 (see RT #53457)

[Christopher Allen Wing]

On Thu, 8 Feb 2007, Derrick J Brashear wrote:

> On Thu, 8 Feb 2007, Marcus Watts wrote:
>
>> Christopher Allen Wing <wingc@engin.umich.edu> writes:
>> ...
>>> There does not seem to be a good way to find out (e.g., autoconf test) if
>>> a particular linux kernel has the 'old' or 'new' semantics of
>>> flock_lock_file*(). The argument types of the functions have not changed.
>> ...
>> 
>> This sounds like it's a feature that is almost exactly
>> tied to linux kernel version.  Testing the Linux kernel
>
> Except for people like RedHat, Fedora, SuSe, who cherrypick patches.
>
>> should suffice to determine if the new locking semantics
>> are true.
>
> Nope.

indeed.


this is what I am testing now.  I believe it should be safe everywhere, 
and keep the existing semantics:


--- openafs-1.4.2/src/afs/LINUX/osi_vnodeops.c.orig	2007-02-08 14:22:27.000000000 -0500
+++ openafs-1.4.2/src/afs/LINUX/osi_vnodeops.c	2007-02-08 14:28:26.000000000 -0500
@@ -475,10 +475,8 @@
      if ((code == 0 || flp->fl_type == F_UNLCK) &&
          (cmd == F_SETLK || cmd == F_SETLKW)) {
  #ifdef AFS_LINUX26_ENV
-       struct file_lock flp2;
-       flp2 = *flp;
-       flp2.fl_flags &=~ FL_SLEEP;
-       code = posix_lock_file(fp, &flp2);
+       flp->fl_flags &=~ FL_SLEEP;
+       code = posix_lock_file(fp, flp);
  #else
         code = posix_lock_file(fp, flp, 0);
  #endif 
@@ -534,10 +532,8 @@

      if ((code == 0 || flp->fl_type == F_UNLCK) &&
          (cmd == F_SETLK || cmd == F_SETLKW)) {
-       struct file_lock flp2;
-       flp2 = *flp;
-       flp2.fl_flags &=~ FL_SLEEP;
-       code = flock_lock_file_wait(fp, &flp2);
+       flp->fl_flags &=~ FL_SLEEP;
+       code = flock_lock_file_wait(fp, flp);
         if (code && flp->fl_type != F_UNLCK) {
             struct AFS_FLOCK flock2;
             flock2 = flock;