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144 Commits (3062c532ad410fe0e8320566fe2879a396be6701)

Author SHA1 Message Date
Trond Myklebust 9936781d01 NFSv4: Try to recover from getfh failures in nfs4_xdr_dec_open
Try harder to recover the open state if the server failed to return a
filehandle.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-07-19 15:09:03 -04:00
Trond Myklebust 56659e9926 NFSv4: 'constify' lookup arguments.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-07-19 15:09:03 -04:00
Trond Myklebust 6f220ed5a8 NFSv4: Fix open state recovery
Ensure that opendata->state is always initialised when we do state
recovery.

Ensure that we set the filehandle in the case where we're doing an
"OPEN_CLAIM_PREVIOUS" call due to a server reboot.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-07-19 15:09:03 -04:00
Frank Filz 137d6acaa6 NFSv4: Make sure unlock is really an unlock when cancelling a lock
I ran into a curious issue when a lock is being canceled. The
cancellation results in a lock request to the vfs layer instead of an
unlock request. This is particularly insidious when the process that
owns the lock is exiting. In that case, sometimes the erroneous lock is
applied AFTER the process has entered zombie state, preventing the lock
from ever being released. Eventually other processes block on the lock
causing a slow degredation of the system. In the 2.6.16 kernel this was
investigated on, the problem is compounded by the fact that the cl_sem
is held while blocking on the vfs lock, which results in most processes
accessing the nfs file system in question hanging.

In more detail, here is how the situation occurs:

first _nfs4_do_setlk():

static int _nfs4_do_setlk(struct nfs4_state *state, int cmd, struct file_lock *fl, int reclaim)
...
        ret = nfs4_wait_for_completion_rpc_task(task);
        if (ret == 0) {
...
        } else
                data->cancelled = 1;

then nfs4_lock_release():

static void nfs4_lock_release(void *calldata)
...
        if (data->cancelled != 0) {
                struct rpc_task *task;
                task = nfs4_do_unlck(&data->fl, data->ctx, data->lsp,
                                data->arg.lock_seqid);

The problem is the same file_lock that was passed in to _nfs4_do_setlk()
gets passed to nfs4_do_unlck() from nfs4_lock_release(). So the type is
still F_RDLCK or FWRLCK, not F_UNLCK. At some point, when cancelling the
lock, the type needs to be changed to F_UNLCK. It seemed easiest to do
that in nfs4_do_unlck(), but it could be done in nfs4_lock_release().
The concern I had with doing it there was if something still needed the
original file_lock, though it turns out the original file_lock still
needs to be modified by nfs4_do_unlck() because nfs4_do_unlck() uses the
original file_lock to pass to the vfs layer, and a copy of the original
file_lock for the RPC request.

It seems like the simplest solution is to force all situations where
nfs4_do_unlck() is being used to result in an unlock, so with that in
mind, I made the following change:

Signed-off-by: Frank Filz <ffilzlnx@us.ibm.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-07-10 23:40:49 -04:00
Trond Myklebust 8bda4e4c98 NFSv4: Fix up stateid locking...
We really don't need to grab both the state->so_owner and the
inode->i_lock.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-07-10 23:40:43 -04:00
Trond Myklebust 1ac7e2fd35 NFSv4: Clean up the callers of nfs4_open_recover_helper()
Rely on nfs4_try_open_cached() when appropriate.

Also fix an RCU violation in _nfs4_do_open_reclaim()

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-07-10 23:40:43 -04:00
Trond Myklebust 6ee4126890 NFSv4: Don't call OPEN if we already have an open stateid for a file
If we already have a stateid with the correct open mode for a given file,
then we can reuse that stateid instead of re-issuing an OPEN call without
violating the close-to-open caching semantics.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-07-10 23:40:43 -04:00
Trond Myklebust aac00a8d0a NFSv4: Check for the existence of a delegation in nfs4_open_prepare()
We should not be calling open() on an inode that has a delegation unless
we're doing a reclaim.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-07-10 23:40:43 -04:00
Trond Myklebust 3e309914a1 NFSv4: Clean up _nfs4_proc_open()
Use a flag instead of the 'data->rpc_status = -ENOMEM hack.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-07-10 23:40:42 -04:00
Trond Myklebust 1b370bc28f NFSv4: Allow nfs4_opendata_to_nfs4_state to return errors.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-07-10 23:40:42 -04:00
Trond Myklebust 6f43ddccb3 NFSv4: Improve the debugging of bad sequence id errors...
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-07-10 23:40:42 -04:00
Trond Myklebust 003707c722 NFSv4: Always use the delegation if we have one
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-07-10 23:40:41 -04:00
Trond Myklebust 0f9f95e0ad NFSv4: Clean up confirmation of sequence ids...
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-07-10 23:40:41 -04:00
Trond Myklebust 13437e12fb NFSv4: Support recalling delegations by stateid part 2
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-07-10 23:40:41 -04:00
Trond Myklebust 2ced46c270 NFSv4: Fix up a bug in nfs4_open_recover()
Don't clobber the delegation info...

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-07-10 23:40:40 -04:00
Trond Myklebust 549d6ed5e8 NFSv4: set the delegation in nfs4_opendata_to_nfs4_state
This ensures that nfs4_open_release() and nfs4_open_confirm_release()
can now handle an eventual delegation that was returned with out open.
As such, it fixes a delegation "leak" when the user breaks out of an open
call.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-07-10 23:40:40 -04:00
Trond Myklebust 1b45c46cf7 NFSv4: Fix atomic open for execute...
Currently we do not check for the FMODE_EXEC flag as we should. For that
particular case, we need to perform an ACCESS call to the server in order
to check that the file is executable.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-07-10 23:40:40 -04:00
Trond Myklebust 9f958ab885 NFSv4: Reduce the chances of an open_owner identifier collision
Currently we just use a 32-bit counter.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-07-10 23:40:39 -04:00
Trond Myklebust 4e56e082dd NFSv4: Clean up _nfs4_proc_lookup() vs _nfs4_proc_lookupfh()
They differ only slightly in the arguments they take. Why have they not
been merged?

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-07-10 23:40:38 -04:00
Trond Myklebust c6d00e639b NFSv4: Convert struct nfs4_opendata to use struct kref
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-07-10 23:40:28 -04:00
Jeff Layton aa53ed541a NFS4: on a O_EXCL OPEN make sure SETATTR sets the fields holding the verifier
The Linux NFS4 client simply skips over the bitmask in an O_EXCL open
call and so it doesn't bother to reset any fields that may be holding
the verifier. This patch has us save the first two words of the bitmask
(which is all the current client has #defines for). The client then
later checks this bitmask and turns on the appropriate flags in the
sattr->ia_verify field for the following SETATTR call.

This patch only currently checks to see if the server used the atime
and mtime slots for the verifier (which is what the Linux server uses
for this). I'm not sure of what other fields the server could
reasonably use, but adding checks for others should be trivial.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-07-10 23:40:25 -04:00
Trond Myklebust b39e625b6e NFSv4: Clean up nfs4_call_async()
Use rpc_run_task() instead of doing it ourselves.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-07-10 23:40:24 -04:00
Trond Myklebust 4a35bd41af NFSv4: Ensure that nfs4_do_close() doesn't race with umount
nfs4_do_close() does not currently have any way to ensure that the user
won't attempt to unmount the partition while the asynchronous RPC call
is completing. This again may cause Oopses in nfs_update_inode().

Add a vfsmount argument to nfs4_close_state to ensure that the partition
remains mounted while we're closing the file.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-07-10 23:40:24 -04:00
Trond Myklebust ad389da79f NFSv4: Ensure asynchronous open() calls always pin the mountpoint
A number of race conditions may currently ensue if the user presses ^C
and then unmounts the partition while an asynchronous open() is in
progress.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-07-10 23:40:24 -04:00
Trond Myklebust 539cd03a57 NFSv4: Cleanup: pass the nfs_open_context to open recovery code
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-07-10 23:40:24 -04:00
Trond Myklebust 88be9f990f NFS: Replace vfsmount and dentry in nfs_open_context with struct path
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-07-10 23:40:23 -04:00
Trond Myklebust 10afec9081 NFS: Fix some 'sparse' warnings...
- fs/nfs/dir.c:610:8: warning: symbol 'nfs_llseek_dir' was not declared.
   Should it be static?
 - fs/nfs/dir.c:636:5: warning: symbol 'nfs_fsync_dir' was not declared.
   Should it be static?
 - fs/nfs/write.c:925:19: warning: symbol 'req' shadows an earlier one
 - fs/nfs/write.c:61:6: warning: symbol 'nfs_commit_rcu_free' was not
   declared. Should it be static?
 - fs/nfs/nfs4proc.c:793:5: warning: symbol 'nfs4_recover_expired_lease'
   was not declared. Should it be static?

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-05-14 19:33:46 -04:00
Linus Torvalds 2d56d3c43c Merge branch 'server-cluster-locking-api' of git://linux-nfs.org/~bfields/linux
* 'server-cluster-locking-api' of git://linux-nfs.org/~bfields/linux:
  gfs2: nfs lock support for gfs2
  lockd: add code to handle deferred lock requests
  lockd: always preallocate block in nlmsvc_lock()
  lockd: handle test_lock deferrals
  lockd: pass cookie in nlmsvc_testlock
  lockd: handle fl_grant callbacks
  lockd: save lock state on deferral
  locks: add fl_grant callback for asynchronous lock return
  nfsd4: Convert NFSv4 to new lock interface
  locks: add lock cancel command
  locks: allow {vfs,posix}_lock_file to return conflicting lock
  locks: factor out generic/filesystem switch from setlock code
  locks: factor out generic/filesystem switch from test_lock
  locks: give posix_test_lock same interface as ->lock
  locks: make ->lock release private data before returning in GETLK case
  locks: create posix-to-flock helper functions
  locks: trivial removal of unnecessary parentheses
2007-05-07 12:34:24 -07:00
J. Bruce Fields 70cc6487a4 locks: make ->lock release private data before returning in GETLK case
The file_lock argument to ->lock is used to return the conflicting lock
when found.  There's no reason for the filesystem to return any private
information with this conflicting lock, but nfsv4 is.

Fix nfsv4 client, and modify locks.c to stop calling fl_release_private
for it in this case.

Signed-off-by: "J. Bruce Fields" <bfields@citi.umich.edu>
Cc: "Trond Myklebust" <Trond.Myklebust@netapp.com>"
2007-05-06 17:38:19 -04:00
J. Bruce Fields 08efa202eb NFS4: invalidate cached acl on setacl
The ACL that the server sets may not be exactly the one we set--for
example, it may silently turn off bits that it does not support.  So we
should remove any cached ACL so that any subsequent request for the ACL
will go to the server.

Signed-off-by: "J. Bruce Fields" <bfields@citi.umich.edu>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-05-02 07:36:09 -07:00
Trond Myklebust d9bc125caf Merge branch 'master' of /home/trondmy/kernel/linux-2.6/
Conflicts:

	net/sunrpc/auth_gss/gss_krb5_crypto.c
	net/sunrpc/auth_gss/gss_spkm3_token.c
	net/sunrpc/clnt.c

Merge with mainline and fix conflicts.
2007-02-12 22:43:25 -08:00
Arjan van de Ven 92e1d5be91 [PATCH] mark struct inode_operations const 2
Many struct inode_operations in the kernel can be "const".  Marking them const
moves these to the .rodata section, which avoids false sharing with potential
dirty data.  In addition it'll catch accidental writes at compile time to
these shared resources.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-12 09:48:46 -08:00
Trond Myklebust e148582e10 NFSv4: Add lockdep checks to nfs4_wait_clnt_recover()
Attempt to detect deadlocks due to caller holding locks on clp->cl_sem

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-02-03 15:35:08 -08:00
Trond Myklebust a6a352e93d NFSv4: Don't start state recovery in nfs4_close_done()
We might not even have any open files at this point...

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-02-03 15:35:08 -08:00
Trond Myklebust 8e0969f045 NFS: Remove nfs_readpage_sync()
It makes no sense to maintain 2 parallel systems for reading in pages.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-02-03 15:35:06 -08:00
Trond Myklebust c228fd3aee NFSv4: Cleanups for fs_locations code.
Start long arduous project...  What the hell is

	struct dentry = {};

all about?

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-02-03 15:35:06 -08:00
Robert P. J. Day 5cbded585d [PATCH] getting rid of all casts of k[cmz]alloc() calls
Run this:

	#!/bin/sh
	for f in $(grep -Erl "\([^\)]*\) *k[cmz]alloc" *) ; do
	  echo "De-casting $f..."
	  perl -pi -e "s/ ?= ?\([^\)]*\) *(k[cmz]alloc) *\(/ = \1\(/" $f
	done

And then go through and reinstate those cases where code is casting pointers
to non-pointers.

And then drop a few hunks which conflicted with outstanding work.

Cc: Russell King <rmk@arm.linux.org.uk>, Ian Molton <spyro@f2s.com>
Cc: Mikael Starvik <starvik@axis.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Roman Zippel <zippel@linux-m68k.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Greg KH <greg@kroah.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Paul Fulghum <paulkf@microgate.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Karsten Keil <kkeil@suse.de>
Cc: Mauro Carvalho Chehab <mchehab@infradead.org>
Cc: Jeff Garzik <jeff@garzik.org>
Cc: James Bottomley <James.Bottomley@steeleye.com>
Cc: Ian Kent <raven@themaw.net>
Cc: Steven French <sfrench@us.ibm.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Neil Brown <neilb@cse.unsw.edu.au>
Cc: Jaroslav Kysela <perex@suse.cz>
Cc: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-13 09:05:58 -08:00
Trond Myklebust 200baa2112 NFS: Remove nfs_writepage_sync()
Maintaining two parallel ways of doing synchronous writes is rather
pointless. This patch gets rid of the legacy nfs_writepage_sync(), and
replaces it with the faster asynchronous writes.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-12-06 10:46:38 -05:00
Frank Filz cae823c4c0 NFS: Remove use of the Big Kernel Lock around calls to rpc_call_sync
Remove use of the Big Kernel Lock around calls to rpc_call_sync.

Signed-off-by: Frank Filz <ffilz@us.ibm.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-12-06 10:46:31 -05:00
Trond Myklebust e6b3c4db6f Fix a second potential rpc_wakeup race...
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-12-06 10:46:25 -05:00
Al Viro bc4785cd47 [PATCH] nfs: verifier is network-endian
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Acked-by: Trond Myklebust <trond.myklebust@fys.uio.no>
Acked-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-20 10:26:40 -07:00
Al Viro 0dbb4c6799 [PATCH] xdr annotations: NFS readdir entries
on-the-wire data is big-endian

[in large part pulled from Alexey's patch]

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Acked-by: Trond Myklebust <trond.myklebust@fys.uio.no>
Acked-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-20 10:26:40 -07:00
Chuck Lever b87c0adfea [PATCH] NFS: remove unused check in nfs4_open_revalidate
Coverity spotted a superfluous error check in nfs4_open_revalidate().  Remove
it.

Coverity: #cid 847

Test plan:
Code inspection; another pass through Coverity.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-20 10:26:39 -07:00
Trond Myklebust 2066fe89b4 NFSv4: Poll more aggressively when handling NFS4ERR_DELAY
Change the initial retry delay from 1s to 0.1s (and then back off
exponentially).

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-09-22 23:25:04 -04:00
Trond Myklebust c514983d8d NFSv4: Handle the condition NFS4ERR_FILE_OPEN
Retry a few times before we give up: the error is usually due to ordering
issues with asynchronous RPC calls.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-09-22 23:25:03 -04:00
Trond Myklebust 6b30954ebb NFSv4: Retry lease recovery if it failed during a synchronous operation.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-09-22 23:25:03 -04:00
Chuck Lever 94a6d75320 NFS: Use cached page as buffer for NFS symlink requests
Now that we have a copy of the symlink path in the page cache, we can pass
a struct page down to the XDR routines instead of a string buffer.

Test plan:
Connectathon, all NFS versions.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-09-22 23:24:53 -04:00
Chuck Lever 4f390c152b NFS: Fix double d_drop in nfs_instantiate() error path
If the LOOKUP or GETATTR in nfs_instantiate fail, nfs_instantiate will do a
d_drop before returning.  But some callers already do a d_drop in the case
of an error return.  Make certain we do only one d_drop in all error paths.

This issue was introduced because over time, the symlink proc API diverged
slightly from the create/mkdir/mknod proc API.  To prevent other coding
mistakes of this type, change the symlink proc API to be more like
create/mkdir/mknod and move the nfs_instantiate call into the symlink proc
routines so it is used in exactly the same way for create, mkdir, mknod,
and symlink.

Test plan:
Connectathon, all versions of NFS.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-09-22 23:24:52 -04:00
David Howells 54ceac4515 NFS: Share NFS superblocks per-protocol per-server per-FSID
The attached patch makes NFS share superblocks between mounts from the same
server and FSID over the same protocol.

It does this by creating each superblock with a false root and returning the
real root dentry in the vfsmount presented by get_sb(). The root dentry set
starts off as an anonymous dentry if we don't already have the dentry for its
inode, otherwise it simply returns the dentry we already have.

We may thus end up with several trees of dentries in the superblock, and if at
some later point one of anonymous tree roots is discovered by normal filesystem
activity to be located in another tree within the superblock, the anonymous
root is named and materialises attached to the second tree at the appropriate
point.

Why do it this way? Why not pass an extra argument to the mount() syscall to
indicate the subpath and then pathwalk from the server root to the desired
directory? You can't guarantee this will work for two reasons:

 (1) The root and intervening nodes may not be accessible to the client.

     With NFS2 and NFS3, for instance, mountd is called on the server to get
     the filehandle for the tip of a path. mountd won't give us handles for
     anything we don't have permission to access, and so we can't set up NFS
     inodes for such nodes, and so can't easily set up dentries (we'd have to
     have ghost inodes or something).

     With this patch we don't actually create dentries until we get handles
     from the server that we can use to set up their inodes, and we don't
     actually bind them into the tree until we know for sure where they go.

 (2) Inaccessible symbolic links.

     If we're asked to mount two exports from the server, eg:

	mount warthog:/warthog/aaa/xxx /mmm
	mount warthog:/warthog/bbb/yyy /nnn

     We may not be able to access anything nearer the root than xxx and yyy,
     but we may find out later that /mmm/www/yyy, say, is actually the same
     directory as the one mounted on /nnn. What we might then find out, for
     example, is that /warthog/bbb was actually a symbolic link to
     /warthog/aaa/xxx/www, but we can't actually determine that by talking to
     the server until /warthog is made available by NFS.

     This would lead to having constructed an errneous dentry tree which we
     can't easily fix. We can end up with a dentry marked as a directory when
     it should actually be a symlink, or we could end up with an apparently
     hardlinked directory.

     With this patch we need not make assumptions about the type of a dentry
     for which we can't retrieve information, nor need we assume we know its
     place in the grand scheme of things until we actually see that place.

This patch reduces the possibility of aliasing in the inode and page caches for
inodes that may be accessed by more than one NFS export. It also reduces the
number of superblocks required for NFS where there are many NFS exports being
used from a server (home directory server + autofs for example).

This in turn makes it simpler to do local caching of network filesystems, as it
can then be guaranteed that there won't be links from multiple inodes in
separate superblocks to the same cache file.

Obviously, cache aliasing between different levels of NFS protocol could still
be a problem, but at least that gives us another key to use when indexing the
cache.

This patch makes the following changes:

 (1) The server record construction/destruction has been abstracted out into
     its own set of functions to make things easier to get right.  These have
     been moved into fs/nfs/client.c.

     All the code in fs/nfs/client.c has to do with the management of
     connections to servers, and doesn't touch superblocks in any way; the
     remaining code in fs/nfs/super.c has to do with VFS superblock management.

 (2) The sequence of events undertaken by NFS mount is now reordered:

     (a) A volume representation (struct nfs_server) is allocated.

     (b) A server representation (struct nfs_client) is acquired.  This may be
     	 allocated or shared, and is keyed on server address, port and NFS
     	 version.

     (c) If allocated, the client representation is initialised.  The state
     	 member variable of nfs_client is used to prevent a race during
     	 initialisation from two mounts.

     (d) For NFS4 a simple pathwalk is performed, walking from FH to FH to find
     	 the root filehandle for the mount (fs/nfs/getroot.c).  For NFS2/3 we
     	 are given the root FH in advance.

     (e) The volume FSID is probed for on the root FH.

     (f) The volume representation is initialised from the FSINFO record
     	 retrieved on the root FH.

     (g) sget() is called to acquire a superblock.  This may be allocated or
     	 shared, keyed on client pointer and FSID.

     (h) If allocated, the superblock is initialised.

     (i) If the superblock is shared, then the new nfs_server record is
     	 discarded.

     (j) The root dentry for this mount is looked up from the root FH.

     (k) The root dentry for this mount is assigned to the vfsmount.

 (3) nfs_readdir_lookup() creates dentries for each of the entries readdir()
     returns; this function now attaches disconnected trees from alternate
     roots that happen to be discovered attached to a directory being read (in
     the same way nfs_lookup() is made to do for lookup ops).

     The new d_materialise_unique() function is now used to do this, thus
     permitting the whole thing to be done under one set of locks, and thus
     avoiding any race between mount and lookup operations on the same
     directory.

 (4) The client management code uses a new debug facility: NFSDBG_CLIENT which
     is set by echoing 1024 to /proc/net/sunrpc/nfs_debug.

 (5) Clone mounts are now called xdev mounts.

 (6) Use the dentry passed to the statfs() op as the handle for retrieving fs
     statistics rather than the root dentry of the superblock (which is now a
     dummy).

Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-09-22 23:24:37 -04:00
David Howells 8fa5c000d7 NFS: Move rpc_ops from nfs_server to nfs_client
Move the rpc_ops from the nfs_server struct to the nfs_client struct as they're
common to all server records of a particular NFS protocol version.

Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-09-22 23:24:35 -04:00