On Apr 26, 2008, at 11:38 AM, Frank A. Kingswood wrote:
Steinar H. Gunderson wrote:
I've gotten a few bug reports lately that if UDP is blocked at the
server,
NFS mounts (even with -o tcp) fail. git bisect shows that the
culprit is
the change "Get rid of the "-i" option for mount.nfs[4] and always
use the
text-based mount(2) system call for kernel version 2.6.23 and
later." -- in
other words, the bug is specific to the text interface. Does anyone
know why
this would be the case?
The NFS client code (nfs-utils-1.1.2) tests for
if (kernel_version > MAKE_VERSION(2, 6, 22))
yet the kernel patch for NFS did not go un until 2.6.25-rc2
From: Linus Torvalds <torvalds@...>
Subject: Linux 2.6.25-rc2
Date: Feb 15, 5:23 pm 2008
Ok,
this kernel is a winner.
[...]
Chuck Lever (1):
NFS: Allow text-based mounts via compat_sys_mount
So the test should at least be > MAKE_VERSION(2, 6, 24).
Frank, the patch you refer to fixes a bug with the compat_sys_mount
interface, which is separate from the sys_mount interface, and used
only on a handful of hardware platforms (SPARC?).
The original NFS text-based mount support was added in 2.6.23.
I don't have a problem with adjusting MAKE_VERSION in the master nfs-
utils repo as you describe, since that bug does break text-based
mounts on those few hardware platforms that use compat_sys_mount
instead of sys_mount. It might affect some early adopters of NFS over
RDMA or FS cache, however.
On distributions that don't support NFS over RDMA or the FS cache
facility, it should be harmless for now to make the mount command use
the legacy mount API even on newer kernels. Simply adjust the
MAKE_VERSION() macro as needed, or disable it entirely as you did with
your "string = 0" hack.
New features will be added only to the text-based mount interface,
however, so eventually everyone will need to use the text-based mount
interface on new kernels.
Because we have little documented history and only a handful of use
cases and unit tests for the mount command, it's important for
everyone to test the new API and report problems here so we can
address them. NFS mount is complex and has many subtle and hidden
historical behaviors.
Even if 70-80% of the common use cases are working properly, there are
going to be outliers that will experience issues until we can get the
corner cases fixed.
--
Chuck Lever
chuck[dot]lever[at]oracle[dot]com
--
To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
