9 Commits

Author SHA1 Message Date
rmacklem
c82d89183d Move the NFSv4.1 client patches over from projects/nfsv4.1-client
to head. I don't think the NFS client behaviour will change unless
the new "minorversion=1" mount option is used. It includes basic
NFSv4.1 support plus support for pNFS using the Files Layout only.
All problems detecting during an NFSv4.1 Bakeathon testing event
in June 2012 have been resolved in this code and it has been tested
against the NFSv4.1 server available to me.
Although not reviewed, I believe that kib@ has looked at it.
2012-12-08 22:52:39 +00:00
rmacklem
6a6a18bf5c PR# 165923 reported intermittent write failures for dirty
memory mapped pages being written back on an NFS mount.
Since any thread can call VOP_PUTPAGES() to write back a
dirty page, the credentials of that thread may not have
write access to the file on an NFS server. (Often the uid
is 0, which may be mapped to "nobody" in the NFS server.)
Although there is no completely correct fix for this
(NFS servers check access on every write RPC instead of at
open/mmap time), this patch avoids the common cases by
holding onto a credential that recently opened the file
for writing and uses that credential for the write RPCs
being done by VOP_PUTPAGES() for both NFS clients.

Tested by:	Joel Ray Holveck (joelh at juniper.net)
PR:		kern/165923
Reviewed by:	kib
MFC after:	2 weeks
2012-05-12 12:02:51 +00:00
jhb
f75e35e4d7 Close a race in NFS lookup processing that could result in stale name cache
entries on one client when a directory was renamed on another client.  The
root cause for the stale entry being trusted is that each per-vnode nfsnode
structure has a single 'n_ctime' timestamp used to validate positive name
cache entries.  However, if there are multiple entries for a single vnode,
they all share a single timestamp.  To fix this, extend the name cache
to allow filesystems to optionally store a timestamp value in each name
cache entry.  The NFS clients now fetch the timestamp associated with
each name cache entry and use that to validate cache hits instead of the
timestamps previously stored in the nfsnode.  Another part of the fix is
that the NFS clients now use timestamps from the post-op attributes of
RPCs when adding name cache entries rather than pulling the timestamps out
of the file's attribute cache.  The latter is subject to races with other
lookups updating the attribute cache concurrently.  Some more details:
- Add a variant of nfsm_postop_attr() to the old NFS client that can return
  a vattr structure with a copy of the post-op attributes.
- Handle lookups of "." as a special case in the NFS clients since the name
  cache does not store name cache entries for ".", so we cannot get a
  useful timestamp.  It didn't really make much sense to recheck the
  attributes on the the directory to validate the namecache hit for "."
  anyway.
- ABI compat shims for the name cache routines are present in this commit
  so that it is safe to MFC.

MFC after:	2 weeks
2012-01-20 20:02:01 +00:00
rmacklem
afa0f6e53c Fix a LOR in the NFS client which could cause a deadlock.
This was reported to the mailing list freebsd-net@freebsd.org
on July 21, 2011 under the subject "LOR with nfsclient sillyrename".
The LOR occurred when nfs_inactive() called vrele(sp->s_dvp)
while holding the vnode lock on the file in s_dvp. This patch
modifies the client so that it performs the vrele(sp->s_dvp)
as a separate task to avoid the LOR. This fix was discussed
with jhb@ and kib@, who both proposed variations of it.

Tested by:	pho, jlott at averesystems.com
Submitted by:	jhb (earlier version)
Reviewed by:	kib
Approved by:	re (kib)
MFC after:	2 weeks
2011-08-02 11:28:42 +00:00
rmacklem
d77942ccd4 Add a lktype flags argument to nfscl_nget() and ncl_nget() in the
experimental NFS client so that its nfs_lookup() function can use
cn_lkflags in a manner analagous to the regular NFS client.

MFC after:	2 weeks
2011-04-16 23:20:21 +00:00
jhb
0f939dc96e Store the full timestamp when caching timestamps of files and
directories for purposes of validating name cache entries.  This
closes races where two updates to a file or directory within the same
second could result in stale entries in the name cache.  While here,
remove the 'n_expiry' field as it is no longer used.

Reviewed by:	rmacklem
MFC after:	1 week
2010-09-07 14:29:45 +00:00
jhb
6f863ac2c4 Retire the NFS access cache timestamp structure. It was used in VOP_OPEN()
to avoid sending multiple ACCESS/GETATTR RPCs during a single open()
between VOP_LOOKUP() and VOP_OPEN().  Now we always send the RPC in
VOP_LOOKUP() and not VOP_OPEN() in the cases that multiple RPCs could be
sent.

MFC after:	2 weeks
2010-07-15 19:40:48 +00:00
rmacklem
f54e0fab4c Patch the experimental NFS client so that there is a timeout
for negative name cache entries in a manner analogous to
r202767 for the regular NFS client. Also, make the code in
nfs_lookup() compatible with that of the regular client
and replace the sysctl variable that enabled negative name
caching with the mount point option.

MFC after:	2 weeks
2010-01-31 19:12:24 +00:00
rmacklem
e3d34903b6 Add the experimental nfs subtree to the kernel, that includes
support for NFSv4 as well as NFSv2 and 3.
	It lives in 3 subdirs under sys/fs:
	nfs - functions that are common to the client and server
	nfsclient - a mutation of sys/nfsclient that call generic functions
	to do RPCs and handle state. As such, it retains the
	buffer cache handling characteristics and vnode semantics that
	are found in sys/nfsclient, for the most part.
	nfsserver - the server. It includes a DRC designed specifically for
	NFSv4, that is used instead of the generic DRC in sys/rpc.
	The build glue will be checked in later, so at this point, it
	consists of 3 new subdirs that should not affect kernel building.

Approved by:	kib (mentor)
2009-05-04 15:23:58 +00:00