linux-toradex.git/fs/lockd/host.c, branch v2.6.27.12

Merge git://git.linux-nfs.org/projects/trondmy/nfs-2.6

2008-04-24T18:46:16+00:00

* git://git.linux-nfs.org/projects/trondmy/nfs-2.6: (80 commits)
  SUNRPC: Invalidate the RPCSEC_GSS session if the server dropped the request
  make nfs_automount_list static
  NFS: remove duplicate flags assignment from nfs_validate_mount_data
  NFS - fix potential NULL pointer dereference v2
  SUNRPC: Don't change the RPCSEC_GSS context on a credential that is in use
  SUNRPC: Fix a race in gss_refresh_upcall()
  SUNRPC: Don't disconnect more than once if retransmitting NFSv4 requests
  SUNRPC: Remove the unused export of xprt_force_disconnect
  SUNRPC: remove XS_SENDMSG_RETRY
  SUNRPC: Protect creds against early garbage collection
  NFSv4: Attempt to use machine credentials in SETCLIENTID calls
  NFSv4: Reintroduce machine creds
  NFSv4: Don't use cred->cr_ops->cr_name in nfs4_proc_setclientid()
  nfs: fix printout of multiword bitfields
  nfs: return negative error value from nfs{,4}_stat_to_errno
  NLM/lockd: Ensure client locking calls use correct credentials
  NFS: Remove the buggy lock-if-signalled case from do_setlk()
  NLM/lockd: Fix a race when cancelling a blocking lock
  NLM/lockd: Ensure that nlmclnt_cancel() returns results of the CANCEL call
  NLM: Remove the signal masking in nlmclnt_proc/nlmclnt_cancel
  ...

lockd: convert nsm_mutex to a spinlock

2008-04-23T20:13:39+00:00

There's no reason for a mutex here, except to allow an allocation under
the lock, which we can avoid with the usual trick of preallocating
memory for the new object and freeing it if it turns out to be
unnecessary.

Signed-off-by: J. Bruce Fields

lockd: clean up __nsm_find()

2008-04-23T20:13:39+00:00

Use list_for_each_entry().  Also, in keeping with kernel style, make the
normal case (kzalloc succeeds) unindented and handle the abnormal case
with a goto.

Signed-off-by: J. Bruce Fields

lockd: fix race in nlm_release()

2008-04-23T20:13:39+00:00

The sm_count is decremented to zero but left on the nsm_handles list.
So in the space between decrementing sm_count and acquiring nsm_mutex,
it is possible for another task to find this nsm_handle, increment the
use count and then enter nsm_release itself.

Thus there's nothing to prevent the nsm being freed before we acquire
nsm_mutex here.

Signed-off-by: J. Bruce Fields

knfsd: Remove NLM_HOST_MAX and associated logic.

2008-04-23T20:13:35+00:00

Lockd caches information about hosts that have recently held locks to
expedite the taking of further locks.

It periodically discards this information for hosts that have not been
used for a few minutes.

lockd currently has a value NLM_HOST_MAX, and changes the 'garbage
collection' behaviour when the number of hosts exceeds this threshold.

However its behaviour is strange, and likely not what was intended.
When the number of hosts exceeds the max, it scans *less* often (every
2 minutes vs every minute) and allows unused host information to
remain around longer (5 minutes instead of 2).

Having this limit is of dubious value anyway, and we have not
suffered from the code not getting the limit right, so remove the
limit altogether.  We go with the larger values (discard 5 minute old
hosts every 2 minutes) as they are probably safer.

Maybe the periodic garbage collection should be replace to with
'shrinker' handler so we just respond to memory pressure....

Acked-by: Jeff Layton 
Signed-off-by: Neil Brown 
Signed-off-by: J. Bruce Fields

NLM: NLM protocol version numbers are u32

2008-03-19T22:00:47+00:00

Clean up: RPC protocol version numbers are u32.  Make sure we use an
appropriate type for NLM version numbers when calling nlm_lookup_host().

Eliminates a harmless mixed sign comparison in nlm_host_lookup().

Signed-off-by: Chuck Lever 
Signed-off-by: Trond Myklebust

NLM: have server-side RPC clients default to soft RPC tasks

2008-02-10T23:09:36+00:00

Now that it no longer does an RPC ping, lockd always ends up queueing
an RPC task for the GRANT_MSG callback. But, it also requeues the block
for later attempts. Since these are hard RPC tasks, if the client we're
calling back goes unresponsive the GRANT_MSG callbacks can stack up in
the RPC queue.

Fix this by making server-side RPC clients default to soft RPC tasks.
lockd requeues the block anyway, so this should be OK.

Signed-off-by: Jeff Layton 
Signed-off-by: J. Bruce Fields

NLM: set RPC_CLNT_CREATE_NOPING for NLM RPC clients

2008-02-10T23:09:36+00:00

It's currently possible for an unresponsive NLM client to completely
lock up a server's lockd. The scenario is something like this:

1) client1 (or a process on the server) takes a lock on a file
2) client2 tries to take a blocking lock on the same file and
   awaits the callback
3) client2 goes unresponsive (plug pulled, network partition, etc)
4) client1 releases the lock

...at that point the server's lockd will try to queue up a GRANT_MSG
callback for client2, but first it requeues the block with a timeout of
30s. nlm_async_call will attempt to bind the RPC client to client2 and
will call rpc_ping. rpc_ping entails a sync RPC call and if client2 is
unresponsive it will take around 60s for that to time out. Once it times
out, it's already time to retry the block and the whole process repeats.

Once in this situation, nlmsvc_retry_blocked will never return until
the host starts responding again. lockd won't service new calls.

Fix this by skipping the RPC ping on NLM RPC clients. This makes
nlm_async_call return quickly when called.

Signed-off-by: Jeff Layton 
Signed-off-by: J. Bruce Fields

NLM: tear down RPC clients in nlm_shutdown_hosts

2008-02-01T21:42:15+00:00

It's possible for a RPC to outlive the lockd daemon that created it, so
we need to make sure that all RPC's are killed when lockd is coming
down. When nlm_shutdown_hosts is called, kill off all RPC tasks
associated with the host. Since we need to wait until they have all gone
away, we might as well just shut down the RPC client altogether.

Signed-off-by: Jeff Layton 
Signed-off-by: J. Bruce Fields

NLM: Fix sign of length of NLM variable length strings

2008-02-01T21:42:02+00:00

According to The Open Group's NLM specification, NLM callers are variable
length strings.  XDR variable length strings use an unsigned 32 bit length.
And internally, negative string lengths are not meaningful for the Linux
NLM implementation.

Clean up: Make nlm_lock.len and nlm_reboot.len unsigned integers.  This
makes the sign of NLM string lengths consistent with the sign of xdr_netobj
lengths.

Signed-off-by: Chuck Lever 
Acked-By: NeilBrown 
Signed-off-by: J. Bruce Fields