Commit Graph

49 Commits

Author SHA1 Message Date
Chuck Lever
dcecae0ff4 NFS: Change nfs4_set_client() to accept struct sockaddr *
Adjust the arguments and callers of nfs4_set_client() to pass a "struct
sockaddr *" instead of a "struct sockaddr_in *" to support non-IPv4
addresses in the NFS client.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Cc: Aurelien Charbon <aurelien.charbon@ext.bull.net>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2008-01-30 02:05:56 -05:00
Chuck Lever
d7422c472b NFS: Change nfs_get_client() to take sockaddr *
Adjust arguments and callers of nfs_get_client() to pass a
"struct sockaddr *" instead of "struct sockaddr_in *" to support
non-IPv4 addresses.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Cc: Aurelien Charbon <aurelien.charbon@ext.bull.net>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2008-01-30 02:05:55 -05:00
Chuck Lever
ff052645c9 NFS: Change nfs_find_client() to take "struct sockaddr *"
Adjust arguments and callers of nfs_find_client() to pass a
"struct sockaddr *" instead of "struct sockaddr_in *" to support non-IPv4
addresses.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Cc: Aurelien Charbon <aurelien.charbon@ext.bull.net>

Trond: Also fix up protocol version number argument in nfs_find_client() to
use the correct u32 type.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2008-01-30 02:05:55 -05:00
Chuck Lever
6e4cffd7b2 NFS: Expand server address storage in nfs_client struct
Prepare for managing larger addresses in the NFS client by widening the
nfs_client struct's cl_addr field.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Cc: Aurelien Charbon <aurelien.charbon@ext.bull.net>

(Modified to work with the new parameters for nfs_alloc_client)
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2008-01-30 02:05:54 -05:00
Trond Myklebust
3b0d3f93d0 NFS: Add support for AF_INET6 addresses in __nfs_find_client()
Introduce AF_INET6-specific address checking to __nfs_find_client().

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2008-01-30 02:05:54 -05:00
Chuck Lever
5d8515caeb NFS: eliminate NIPQUAD(clp->cl_addr.sin_addr)
To ensure the NFS client displays IPv6 addresses properly, replace
address family-specific NIPQUAD() invocations with a call to the RPC
client to get a formatted string representing the remote peer's
address.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Cc: Aurelien Charbon <aurelien.charbon@ext.bull.net>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2008-01-30 02:05:52 -05:00
Trond Myklebust
40c553193d NFS: Remove the redundant nfs_client->cl_nfsversion
We can get the same information from the rpc_ops structure instead.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2008-01-30 02:05:49 -05:00
Trond Myklebust
c81468a1a7 NFS: Clean up the nfs_find_client function.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2008-01-30 02:05:48 -05:00
Trond Myklebust
3a498026ee NFS: Clean up the nfs_client initialisation
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2008-01-30 02:05:48 -05:00
Chuck Lever
d45273ed6f NFS: Clean up address comparison in __nfs_find_client()
The address comparison in the __nfs_find_client() function is deceptive.
It uses a memcmp() to check a pair of u32 fields for equality.  Not only is
this inefficient, but usually memcmp() is used for comparing two *whole*
sockaddr_in's (which includes comparisons of the address family and port
number), so it's easy to mistake the comparison here for a whole sockaddr
comparison, which it isn't.

So for clarity and efficiency, we replace the memcmp() with a simple test
for equality between the two s_addr fields.  This should have no
behavioral effect.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2008-01-30 02:05:46 -05:00
Steve Dickson
ef818a28fa NFS: Stop sillyname renames and unmounts from racing
Added an active/deactive mechanism to the nfs_server structure
allowing async operations to hold off umount until the
operations are done.

Signed-off-by: Steve Dickson <steved@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2008-01-30 02:05:24 -05:00
Trond Myklebust
5cef338b30 NFSv2/v3: Fix a memory leak when using -onolock
Neil Brown said:
> Hi Trond,
> 
> We found that a machine which made moderately heavy use of
> 'automount' was leaking some nfs data structures - particularly the
> 4K allocated by rpc_alloc_iostats.
> It turns out that this only happens with filesystems with -onolock
> set.

> The problem is that if NFS_MOUNT_NONLM is set, nfs_start_lockd doesn't
> set server->destroy, so when the filesystem is unmounted, the
> ->client_acl is not shutdown, and so several resources are still
> held.  Multiple mount/umount cycles will slowly eat away memory
> several pages at a time.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Acked-by: NeilBrown <neilb@suse.de>
2007-12-11 22:01:56 -05:00
Peter Zijlstra
e0bf68ddec mm: bdi init hooks
provide BDI constructor/destructor hooks

[akpm@linux-foundation.org: compile fix]
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-17 08:42:45 -07:00
\"Talpey, Thomas\
2cf7ff7a37 NFS: support RDMA mounts
Adds hooks to the string-based NFS mount to support an "rdma" protocol option.

Signed-off-by: Tom Talpey <tmt@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-10-09 17:18:00 -04:00
\"Talpey, Thomas\
0896a725a1 NFS/SUNRPC: use transport protocol naming
Instead of an { address family, raw IP protocol number }-tuple, use the
newly-defined RPC identifier when creating clients in the upper layers.

Signed-off-by: Tom Talpey <tmt@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-10-09 17:17:53 -04:00
\"Talpey, Thomas\
91ea40b9c6 NFS: use in-kernel mount argument structure for nfsv4 mounts
The user-visible nfs4_mount_data does not contain sufficient data to
describe new mount options, and also is now a legacy structure. Replace
it with the internal nfs_parsed_mount_data for nfsv4 in-kernel use.

Signed-off-by: Tom Talpey <tmt@netapp.com>
Acked-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-10-09 17:17:28 -04:00
\"Talpey, Thomas\
2283f8d6ed NFS: use in-kernel mount argument structure for nfsv[23] mounts
The user-visible nfs_mount_data does not contain sufficient data to
describe new mount options, and also is now a legacy structure. Replace
it with the internal nfs_parsed_mount_data for nfsv[23] in-kernel use.

Signed-off-by: Tom Talpey <tmt@netapp.com>
Acked-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-10-09 17:17:26 -04:00
Trond Myklebust
54af3bb543 NFS: Fix an Oops in encode_lookup()
It doesn't look as if the NFS file name limit is being initialised correctly
in the struct nfs_server. Make sure that we limit whatever is being set in
nfs_probe_fsinfo() and nfs_init_server().

Also ensure that readdirplus and nfs4_path_walk respect our file name
limits.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-09-28 15:36:42 -07:00
Pavel Emelianov
259902ea95 Make NFS client use seq_list_xxx helpers
This includes /proc/fs/nfsfs/servers and /proc/fs/nfsfs/volumes entries.

Both need to show the header and use the list_head.

Signed-off-by: Pavel Emelianov <xemul@openvz.org>
Acked-by: Trond Myklebust <trond.myklebust@fys.uio.no>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-16 09:05:42 -07:00
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
7af654f8d1 NFSv4: Don't reuse expired nfs4_state_owner structs
That just confuses certain NFSv4 servers.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-07-10 23:40:38 -04:00
Trond Myklebust
f61534dfd3 SUNRPC: Remove redundant calls to rpciod_up()/rpciod_down()
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-07-10 23:40:30 -04:00
Alexey Dobriyan
e8edc6e03a Detach sched.h from mm.h
First thing mm.h does is including sched.h solely for can_do_mlock() inline
function which has "current" dereference inside. By dealing with can_do_mlock()
mm.h can be detached from sched.h which is good. See below, why.

This patch
a) removes unconditional inclusion of sched.h from mm.h
b) makes can_do_mlock() normal function in mm/mlock.c
c) exports can_do_mlock() to not break compilation
d) adds sched.h inclusions back to files that were getting it indirectly.
e) adds less bloated headers to some files (asm/signal.h, jiffies.h) that were
   getting them indirectly

Net result is:
a) mm.h users would get less code to open, read, preprocess, parse, ... if
   they don't need sched.h
b) sched.h stops being dependency for significant number of files:
   on x86_64 allmodconfig touching sched.h results in recompile of 4083 files,
   after patch it's only 3744 (-8.3%).

Cross-compile tested on

	all arm defconfigs, all mips defconfigs, all powerpc defconfigs,
	alpha alpha-up
	arm
	i386 i386-up i386-defconfig i386-allnoconfig
	ia64 ia64-up
	m68k
	mips
	parisc parisc-up
	powerpc powerpc-up
	s390 s390-up
	sparc sparc-up
	sparc64 sparc64-up
	um-x86_64
	x86_64 x86_64-up x86_64-defconfig x86_64-allnoconfig

as well as my two usual configs.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-21 09:18:19 -07:00
Randy Dunlap
e63340ae6b header cleaning: don't include smp_lock.h when not used
Remove includes of <linux/smp_lock.h> where it is not used/needed.
Suggested by Al Viro.

Builds cleanly on x86_64, i386, alpha, ia64, powerpc, sparc,
sparc64, and arm (all 59 defconfigs).

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-08 11:15:07 -07:00
Steve Dickson
74dd34e6e8 NFS: Added support to turn off the NFSv3 READDIRPLUS RPC.
READDIRPLUS can be a performance hindrance when the client is working with
large directories. In addition, some servers still have bugs in their
implementations (e.g. Tru64 returns wrong values for the fsid).

Add a mount flag to enable users to turn it off at mount time following the
implementation in Apple's NFS client.

Signed-off-by: Steve Dickson <steved@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-04-30 22:17:16 -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
Chuck Lever
43d78ef2ba NFS: disconnect before retrying NFSv4 requests over TCP
RFC3530 section 3.1.1 states an NFSv4 client MUST NOT send a request
twice on the same connection unless it is the NULL procedure.  Section
3.1.1 suggests that the client should disconnect and reconnect if it
wants to retry a request.

Implement this by adding an rpc_clnt flag that an ULP can use to
specify that the underlying transport should be disconnected on a
major timeout.  The NFSv4 client asserts this new flag, and requests
no retries after a minor retransmit timeout.

Note that disconnecting on a retransmit is in general not safe to do
if the RPC client does not reuse the TCP port number when reconnecting.

See http://bugzilla.linux-nfs.org/show_bug.cgi?id=6

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-02-12 22:40:45 -08:00
Arjan van de Ven
00977a59b9 [PATCH] mark struct file_operations const 6
Many struct file_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 09:48:45 -08:00
Trond Myklebust
f2d0d85e58 NFSv4: Fix Oops in nfs4_create_referral_server
The filehandle that is passed into nfs4_create_referral_server is
not initialised. The expectation is that nfs4_create_referral_server will
initialise it, and return it to the caller.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-02-03 15:35:03 -08:00
David Howells
65f27f3844 WorkStruct: Pass the work_struct pointer instead of context data
Pass the work_struct pointer to the work function rather than context data.
The work function can use container_of() to work out the data.

For the cases where the container of the work_struct may go away the moment the
pending bit is cleared, it is made possible to defer the release of the
structure by deferring the clearing of the pending bit.

To make this work, an extra flag is introduced into the management side of the
work_struct.  This governs auto-release of the structure upon execution.

Ordinarily, the work queue executor would release the work_struct for further
scheduling or deallocation by clearing the pending bit prior to jumping to the
work function.  This means that, unless the driver makes some guarantee itself
that the work_struct won't go away, the work function may not access anything
else in the work_struct or its container lest they be deallocated..  This is a
problem if the auxiliary data is taken away (as done by the last patch).

However, if the pending bit is *not* cleared before jumping to the work
function, then the work function *may* access the work_struct and its container
with no problems.  But then the work function must itself release the
work_struct by calling work_release().

In most cases, automatic release is fine, so this is the default.  Special
initiators exist for the non-auto-release case (ending in _NAR).


Signed-Off-By: David Howells <dhowells@redhat.com>
2006-11-22 14:55:48 +00:00
David Howells
52bad64d95 WorkStruct: Separate delayable and non-delayable events.
Separate delayable work items from non-delayable work items be splitting them
into a separate structure (delayed_work), which incorporates a work_struct and
the timer_list removed from work_struct.

The work_struct struct is huge, and this limits it's usefulness.  On a 64-bit
architecture it's nearly 100 bytes in size.  This reduces that by half for the
non-delayable type of event.

Signed-Off-By: David Howells <dhowells@redhat.com>
2006-11-22 14:54:01 +00:00
Trond Myklebust
13bbc06af8 [PATCH] NFS: Fix NFSv4 callback regression
The change in semantics for nfs_find_client() introduced by David breaks the
NFSv4 callback channel.

Also, replace another completely broken BUG_ON() in nfs_find_client().  In
initialised clients, clp->cl_cons_state == 0, and callers of that function
should in any case never want to see clients that are uninitialised.

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
J. Bruce Fields
7d9ac06f26 [PATCH] nfs4: initialize cl_ipaddr
David forgot to do this.  I'm not sure if this is the right place to put
it....

Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
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
Linus Torvalds
8325049337 Fix extraneous '&' in recent NFS client cleanup
We should pass "wait_event_interruptible()" the wait-queue itself, not
the pointer to it. The magic macro will pointerize it internally.

Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-08 17:28:25 -07:00
Trond Myklebust
0bae89ec8b [PATCH] NFS: Fix typo in nfs_get_client()
Commit ca4aa09635 fixed waiting for the
structure to get initialised, but it is also possible to break out of
the loop while still in TASK_INTERRUPTIBLE.

Replace the whole thing by wait_event_interruptible, which is much more
readable, and doesn't suffer from these problems.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-08 15:34:56 -07:00
Trond Myklebust
ca4aa09635 [PATCH] NFS: Fix typo in nfs_get_client()
NFS_CS_INITING > NFS_CS_READY, so instead of waiting for the structure to
get initialised, we currently immediately jump out of the loop without ever
sleeping.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-08 12:07:03 -07:00
Dave Jones
038b0a6d8d Remove all inclusions of <linux/config.h>
kbuild explicitly includes this at build time.

Signed-off-by: Dave Jones <davej@redhat.com>
2006-10-04 03:38:54 -04:00
NeilBrown
24e36663c3 [PATCH] knfsd: be more selective in which sockets lockd listens on
Currently lockd listens on UDP always, and TCP if CONFIG_NFSD_TCP is set.

However as lockd performs services of the client as well, this is a problem.
If CONFIG_NfSD_TCP is not set, and a tcp mount is used, the server will not be
able to call back to lockd.

So:
 - add an option to lockd_up saying which protocol is needed
 - Always open sockets for which an explicit port was given, otherwise
   only open a socket of the type required
 - Change nfsd to do one lockd_up per socket rather than one per thread.

This
 - removes the dependancy on CONFIG_NFSD_TCP
 - means that lockd may open sockets other than at startup
 - means that lockd will *not* listen on UDP if the only
   mounts are TCP mount (and nfsd hasn't started).

The latter is the only one that concerns me at all - I don't know if this
might be a problem with some servers.

Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-02 07:57:17 -07:00
J. Bruce Fields
2dec51466a NFSv4: It's perfectly legal for clp to be NULL here....
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-09-22 23:25:02 -04:00
andros@citi.umich.edu
297de4f656 Fix a referral error Oops
Fix an oops when the referral server is not responding.
Check the error return from nfs4_set_client() in nfs4_create_referral_server.

Signed-off-by: Andy Adamson <andros@citi.umich.edu>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-09-22 23:24:56 -04:00
David Howells
6daabf1b04 NFS: Fix up compiler warnings on 64-bit platforms in client.c
Fix up warnings from compiling on ppc64.

Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-09-22 23:24:55 -04:00
Trond Myklebust
5dd3177ae5 NFSv4: Fix a use-after-free issue with the nfs server.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-09-22 23:24:54 -04:00
Chuck Lever
41877d207c NFS: Convert NFS client to use new rpc_create() API
Convert NFS client mount logic to use rpc_create() instead of the old
xprt_create_proto/rpc_create_client API.

Test plan:
Mount stress tests.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-09-22 23:24:50 -04:00
Trond Myklebust
9c5bf38d85 NFS: Fix nfs_alloc_client()
The scheme to indicate which services have been started up appears to be
seriously broken.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-09-22 23:24:38 -04:00
David Howells
27ba851244 NFS: Fix error handling
Fix an error handling problem: nfs_put_client() can be given a NULL pointer if
nfs_free_server() is asked to destroy a partially initialised record.

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
6aaca56650 NFS: Add server and volume lists to /proc
Make two new proc files available:

	/proc/fs/nfsfs/servers
	/proc/fs/nfsfs/volumes

The first lists the servers with which we are currently dealing (struct
nfs_client), and the second lists the volumes we have on those servers (struct
nfs_server).

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
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
5006a76cca NFS: Eliminate client_sys in favour of cl_rpcclient
Eliminate nfs_server::client_sys in favour of nfs_client::cl_rpcclient as we
only really need one per server that we're talking to since it doesn't have any
security on it.

The retransmission management variables are also moved to the common struct as
they're required to set up the cl_rpcclient connection.

The NFS2/3 client and client_acl connections are thenceforth derived by cloning
the cl_rpcclient connection and post-applying the authorisation flavour.

The code for setting up the initial common connection has been moved to
client.c as nfs_create_rpc_client().  All the NFS program definition tables are
also moved there as that's where they're now required rather than super.c.

Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-09-22 23:24:36 -04:00
David Howells
24c8dbbb5f NFS: Generalise the nfs_client structure
Generalise the nfs_client structure by:

 (1) Moving nfs_client to a more general place (nfs_fs_sb.h).

 (2) Renaming its maintenance routines to be non-NFS4 specific.

 (3) Move those maintenance routines to a new non-NFS4 specific file (client.c)
     and move the declarations to internal.h.

 (4) Make nfs_find/get_client() take a full sockaddr_in to include the port
     number (will be required for NFS2/3).

 (5) Make nfs_find/get_client() take the NFS protocol version (again will be
     required to differentiate NFS2, 3 & 4 client records).

Also:

 (6) Make nfs_client construction proceed akin to inodes, marking them as under
     construction and providing a function to indicate completion.

 (7) Make nfs_get_client() wait interruptibly if it finds a client that it can
     share, but that client is currently being constructed.

 (8) Make nfs4_create_client() use (6) and (7) instead of locking cl_sem.

Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-09-22 23:24:33 -04:00