To allow transport capabilities to be loaded dynamically, provide an API
for registering and unregistering the transports with the RPC client.
Eventually xprt_create_transport() will be changed to search the list of
registered transports when initializing a fresh transport.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Tom Talpey <tmt@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
SUNRPC: add EXPORT_SYMBOL_GPL for generic transport functions
As a preface to allowing arbitrary transport modules to be loaded
dynamically, add EXPORT_SYMBOL_GPL for all generic transport functions
that a transport implementation might want to use.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Acked-by: Tom Talpey <tmt@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Adds a flag word to the xdrbuf struct which indicates any bulk
disposition of the data. This enables RPC transport providers to
marshal it efficiently/appropriately, and may enable other
optimizations.
Signed-off-by: Tom Talpey <tmt@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
The rpcbind (v3+) netid is provided by each RPC client transport. This fixes
an omission in IPv6 rpcbind client support, and enables future extension.
Signed-off-by: Tom Talpey <tmt@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Move the TCP/UDP rpcbind netid's from the rpcbind client to a global header.
Signed-off-by: Tom Talpey <tmt@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
The purpose of an RPC ping (a NULL request) is to determine whether the
remote end is operating and supports the RPC program and version of the
request.
If we do an RPC bind and the remote's rpcbind service says "this
program or service isn't supported" then we have our answer already,
and we should give up immediately.
This is good for the kernel mount client, as it will cause the request
to fail, and then allow an immediate retry with different options.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Add more new error code processing to the kernel's rpcbind client
and to call_bind_status() to distinguish two cases:
Case 1: the remote has replied that the program/version tuple is not
registered (returns EACCES)
Case 2: retry with a lesser rpcbind version (rpcb now returns EPFNOSUPPORT)
This change allows more specific error processing for each of these two
cases. We now fail case 2 instead of retrying... it's a server
configuration error not to support even rpcbind version 2. And don't
expose this new error code to user land -- convert it to EIO before
failing the RPC.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Add new error code processing to the kernel's rpcbind client and to
call_bind_status() to distinguish two cases:
Case 1: the remote has replied that the program/version tuple is not
registered (returns -EACCES)
Case 2: another process is already in the middle of binding on this
transport (now returns -EAGAIN)
This change allows more specific retry processing for each of these two
cases.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
When a server returns a bad rpcbind reply, make rpcbind client recovery logic
retry with an older protocol version. Older versions are more likely to work
correctly.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Add better sanity checking of server replies to the GETVERSADDR reply
decoder. Change the error return code: EIO is what other XDR decoding
routines return if there is a failure while decoding.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
/home/cel/linux/net/sunrpc/clnt.c: In function ‘rpc_show_tasks’:
/home/cel/linux/net/sunrpc/clnt.c:1538: warning:
signed and unsigned type in conditional expression
This points out another case where a conditional expression returns a
signed value in one arm and an unsigned value in the other.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Check the length of the passed-in server name before trying to print it in
the log.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Noticed by Tom Talpey <tmt@netapp.com>:
OBTW, there's a nit on that memcpy, too. The r_addr is an array, so
memcpy(&map->r_addr
is passing the address of the array as a char **. It's the same as
map->r_addr, but technically the wrong type.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
/home/cel/linux/net/sunrpc/clnt.c: In function ‘rpc_bind_new_program’:
/home/cel/linux/net/sunrpc/clnt.c:445: warning:
comparison between signed and unsigned
RPC version numbers are u32, not int.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Remove one of two identical dprintk's that occur when an RPC client is
created.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Fix some problems with rpcbind v3 and v4 queries from the in-kernel rpcbind
client:
1. The r_addr argument must be a full universal address, not just an IP
address, and
2. The universal address in r_addr is the address of the remote rpcbind
server, not the RPC service being requested
This addresses bugzilla.kernel.org report 8891 for 2.6.23-rc and greater.
In addition, if the rpcbind client is unable to start the rpcbind request,
make sure not to leak the xprt.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
"Universal addresses" are a string representation of an IP address and
port. They are described fully in RFC 3530, section 2.2. Add support
for generating them in the RPC client's socket transport module.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Finalize support for setting up RPC client transports to remote RPC
services addressed via IPv6.
Based on work done by Gilles Quillard at Bull Open Source.
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>
Prepare for introduction of IPv6 versions of same.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Finishing a socket connect is the same for IPv4 and IPv6, so split it out
into a helper.
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>
Clone xs_bindresvport into two functions, one that can handle IPv4
addresses, and one that can handle IPv6 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>
We could clone xs_set_port, but this is easier overall.
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>
Prepare for adding IPv6 support to the RPC client by adding IPv6
capabilities to rpcbind. Note that this is support on the query side
only; registering IPv6 addresses with the local portmapper will come
later.
Note we have to take care not to fall back to using version 2 of the
rpcbind protocol if we're dealing with IPv6 address. Version 2 doesn't
support IPv6 at all.
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>
Prepare to add an IPv6 version of xs_format_peer_addresses by renaming it
to xs_format_ipv4_peer_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>
Add support for the NFS client's need to export volume information
with IP addresses formatted in hex instead of decimal.
This isn't used yet, but subsequent patches (not in this series) will
change the NFS client to use this functionality.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Use more generic logic to free buffers holding formatted addresses. This
makes it less likely a bug will be introduced when adding additional buffer
types in xs_format_peer_address().
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
include/linux/kernel.h gives us some nice macros for formatting IP
addresses. Use them.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
This will allow rpc.gssd to use inotify instead of dnotify in order to
locate new rpc upcall pipes.
This also requires the exporting of __audit_inode_child(), which is used by
fsnotify_create() and fsnotify_mkdir(). Ccing David Woodhouse.
Cc: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
we upgraded the kernel of a nfs-server from 2.6.17.11 to 2.6.22.6. Since
then we get the message
lockd: too many open TCP sockets, consider increasing the number of nfsd threads
lockd: last TCP connect from ^\\236^\É^D
These random characters in the second line are caused by a bug in
svc_tcp_accept.
(Note: there are two previous __svc_print_addr(sin, buf, sizeof(buf))
calls in this function, either of which would initialize buf correctly;
but both are inside "if"'s and are not necessarily executed. This is
less obvious in the second case, which is inside a dprintk(), which is a
macro which expands to an if statement.)
Signed-off-by: Wolfgang Walter <wolfgang.walter@studentenwerk.mhn.de>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit aaf68cfbf2 added a bias
to sk_inuse, so this test for an unused socket now fails. So no
sockets get closed because they are old (they might get closed
if the client closed them).
This bug has existed since 2.6.21-rc1.
Thanks to Wolfgang Walter for finding and reporting the bug.
Cc: Wolfgang Walter <wolfgang.walter@studentenwerk.mhn.de>
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch cleans up duplicate includes in
net/sunrpc/
Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
The commit 4ada539ed7 lead to the unpleasant
possibility of an asynchronous rpc_task being required to call
rpciod_down() when it is complete. This again means that the rpciod
workqueue may get to call destroy_workqueue on itself -> hang...
Change rpciod_up/rpciod_down to just get/put the module, and then
create/destroy the workqueues on module load/unload.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
The handling of the re-registration case is wrong here; the "test" that was
returned from auth_domain_lookup will not be used again, so that reference
should be put. And auth_domain_lookup never did anything with "new" in
this case, so we should just clean it up ourself.
Thanks to Akinobu Mita for bug report, analysis, and testing.
Cc: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: "J. Bruce Fields" <bfields@citi.umich.edu>
Cc: Neil Brown <neilb@suse.de>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Slab destructors were no longer supported after Christoph's
c59def9f22 change. They've been
BUGs for both slab and slub, and slob never supported them
either.
This rips out support for the dtor pointer from kmem_cache_create()
completely and fixes up every single callsite in the kernel (there were
about 224, not including the slab allocator definitions themselves,
or the documentation references).
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Since every invocation of xdr encode or decode functions takes the BKL now,
there's a lot of redundant lock_kernel/unlock_kernel pairs that we can pull
out into a common function.
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
use vfs_path_lookup instead of open-coding the necessary functionality.
Signed-off-by: Josef 'Jeff' Sipek <jsipek@cs.sunysb.edu>
Acked-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Acked-by: Christoph Hellwig <hch@lst.de>
Cc: Neil Brown <neilb@suse.de>
Cc: Michael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We could return some sort of error in the case where someone asks for secinfo
on an export without the secinfo= option set--that'd be no worse than what
we've been doing. But it's not really correct. So, hack up an approximate
secinfo response in that case--it may not be complete, but it'll tell the
client at least one acceptable security flavor.
Signed-off-by: "J. Bruce Fields" <bfields@citi.umich.edu>
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Adds oid values to the gss_api mechanism structures. On the NFSV4 server
side, these are required as part of the security triple (oid,qop,service)
information being sent in the response of the SECINFO operation.
Signed-off-by: Usha Ketineni <uketinen@us.ibm.com>
Signed-off-by: "J. Bruce Fields" <bfields@citi.umich.edu>
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We want it to be possible for users to restrict exports both by IP address and
by pseudoflavor. The pseudoflavor information has previously been passed
using special auth_domains stored in the rq_client field. After the preceding
patch that stored the pseudoflavor in rq_pflavor, that's now superfluous; so
now we use rq_client for the ip information, as auth_null and auth_unix do.
However, we keep around the special auth_domain in the rq_gssclient field for
backwards compatibility purposes, so we can still do upcalls using the old
"gss/pseudoflavor" auth_domain if upcalls using the unix domain to give us an
appropriate export. This allows us to continue supporting old mountd.
In fact, for this first patch, we always use the "gss/pseudoflavor"
auth_domain (and only it) if it is available; thus rq_client is ignored in the
auth_gss case, and this patch on its own makes no change in behavior; that
will be left to later patches.
Note on idmap: I'm almost tempted to just replace the auth_domain in the idmap
upcall by a dummy value--no version of idmapd has ever used it, and it's
unlikely anyone really wants to perform idmapping differently depending on the
where the client is (they may want to perform *credential* mapping
differently, but that's a different matter--the idmapper just handles id's
used in getattr and setattr). But I'm updating the idmapd code anyway, just
out of general backwards-compatibility paranoia.
Signed-off-by: "J. Bruce Fields" <bfields@citi.umich.edu>
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add a new field to the svc_rqst structure to record the pseudoflavor that the
request was made with. For now we record the pseudoflavor but don't use it
for anything.
Signed-off-by: Andy Adamson <andros@citi.umich.edu>
Signed-off-by: "J. Bruce Fields" <bfields@citi.umich.edu>
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
I can never remember what the function to register to receive VM pressure
is called. I have to trace down from __alloc_pages() to find it.
It's called "set_shrinker()", and it needs Your Help.
1) Don't hide struct shrinker. It contains no magic.
2) Don't allocate "struct shrinker". It's not helpful.
3) Call them "register_shrinker" and "unregister_shrinker".
4) Call the function "shrink" not "shrinker".
5) Reduce the 17 lines of waffly comments to 13, but document it properly.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: David Chinner <dgc@sgi.com>
Cc: 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>
* git://git.linux-nfs.org/pub/linux/nfs-2.6: (122 commits)
sunrpc: drop BKL around wrap and unwrap
NFSv4: Make sure unlock is really an unlock when cancelling a lock
NLM: fix source address of callback to client
SUNRPC client: add interface for binding to a local address
SUNRPC server: record the destination address of a request
SUNRPC: cleanup transport creation argument passing
NFSv4: Make the NFS state model work with the nosharedcache mount option
NFS: Error when mounting the same filesystem with different options
NFS: Add the mount option "nosharecache"
NFS: Add support for mounting NFSv4 file systems with string options
NFS: Add final pieces to support in-kernel mount option parsing
NFS: Introduce generic mount client API
NFS: Add enums and match tables for mount option parsing
NFS: Improve debugging output in NFS in-kernel mount client
NFS: Clean up in-kernel NFS mount
NFS: Remake nfsroot_mount as a permanent part of NFS client
SUNRPC: Add a convenient default for the hostname when calling rpc_create()
SUNRPC: Rename rpcb_getport to be consistent with new rpcb_getport_sync name
SUNRPC: Rename rpcb_getport_external routine
SUNRPC: Allow rpcbind requests to be interrupted by a signal.
...
Make all initialized struct seq_operations in net/ const
Signed-off-by: Philippe De Muyter <phdm@macqel.be>
Signed-off-by: David S. Miller <davem@davemloft.net>
We don't need the BKL when wrapping and unwrapping; and experiments by Avishay
Traeger have found that permitting multiple encryption and decryption
operations to proceed in parallel can provide significant performance
improvements.
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Cc: Avishay Traeger <atraeger@cs.sunysb.edu>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
In addition to binding to a local privileged port the NFS client should
allow binding to a specific local address. This is used by the server
for callbacks. The patch adds the necessary interface.
Signed-off-by: Frank van Maarseveen <frankvm@frankvm.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Save the destination address of an incoming request over TCP like is
done already for UDP. It is necessary later for callbacks by the server.
Signed-off-by: Frank van Maarseveen <frankvm@frankvm.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cleanup argument passing to functions for creating an RPC transport.
Signed-off-by: Frank van Maarseveen <frankvm@frankvm.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
A couple of callers just use a stringified IP address for the rpc client's
hostname. Move the logic for constructing this into rpc_create(), so it can
be shared.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Clean up, for consistency. Rename rpcb_getport as rpcb_getport_async, to
match the naming scheme of rpcb_getport_sync.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
In preparation for handling NFS mount option parsing in the kernel,
rename rpcb_getport_external as rpcb_get_port_sync, and make it available
always (instead of only when CONFIG_ROOT_NFS is enabled).
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
This allows NFS mount requests and RPC re-binding to be interruptible if the
server isn't responding.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Add a refcount in order to ensure that the gss_auth doesn't disappear from
underneath us while we're freeing up GSS contexts.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
We should almost always be deferencing the rpc_auth struct by means of the
credential's cr_auth field instead of the rpc_clnt->cl_auth anyway. Fix up
that historical mistake, and remove the macro that propagated it.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
RPCSEC_GSS needs to be able to send NULL RPC calls to the server in order
to free up any remaining GSS contexts.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Does a NULL RPC call and returns a pointer to the resulting rpc_task. The
call may be either synchronous or asynchronous.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Fix a memory leak in gss_create() whereby the rpc credcache was not being
freed if the rpc_mkpipe() call failed.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
We want to set the unix_cred_cache.nextgc on the first call to
unx_create(), which should be when unix_auth.au_count === 1
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
The leak only affects the RPCSEC_GSS caches, since they are the only ones
that are dynamically allocated...
Rename the existing rpcauth_free_credcache() to rpcauth_clear_credcache()
in order to better describe its role, then add a new function
rpcauth_destroy_credcache() that actually frees the cache in addition to
clearing it out.
Also move the call to destroy the credcache in gss_destroy() to come before
the rpc upcall pipe is unlinked.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Add a dentry_ops with a d_delete() method in order to ensure that dentries
are removed as soon as the last reference is gone.
Clean up rpc_depopulate() so that it only removes files that were created
via rpc_populate().
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Currently, the downcall queue is tied to the struct gss_auth, which means
that different RPCSEC_GSS pseudoflavours must use different upcall pipes.
Add a list to struct rpc_inode that can be used instead.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
It used to be possible for an rpc.gssd daemon to stuff the RPC credential
cache for any rpc client simply by creating RPCSEC_GSS contexts and then
doing downcalls. In practice, no daemons ever made use of this feature.
Remove this feature now, since it will be impossible to figure out which
mechanism a given context actually matches if we enable more
than one gss mechanism to use the same upcall pipe.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cleans up an issue whereby rpcsec_gss uses the rpc_clnt->cl_auth. If we want
to be able to add several rpc_auths to a single rpc_clnt, then this abuse
must go.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Brian Behlendorf writes:
The root cause of the NFS hang we were observing appears to be a rare
deadlock between the kernel provided usermodehelper API and the linux NFS
client. The deadlock can arise because both of these services use the
generic linux work queues. The usermodehelper API run the specified user
application in the context of the work queue. And NFS submits both cleanup
and reconnect work to the generic work queue for handling. Normally this
is fine but a deadlock can result in the following situation.
- NFS client is in a disconnected state
- [events/0] runs a usermodehelper app with an NFS dependent operation,
this triggers an NFS reconnect.
- NFS reconnect happens to be submitted to [events/0] work queue.
- Deadlock, the [events/0] work queue will never process the
reconnect because it is blocked on the previous NFS dependent
operation which will not complete.`
The solution is simply to run reconnect requests on rpciod.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Instead of taking the mutex every time we just need to increment/decrement
rpciod_users, we can optmise by using atomic_inc_not_zero and
atomic_dec_and_test.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
The kref now does most of what cl_count + cl_user used to do. The only
remaining role for cl_count is to tell us if we are in a 'shutdown'
phase. We can provide that information using a single bit field instead
of a full atomic counter.
Also rename rpc_destroy_client() to rpc_close_client(), which reflects
better what its role is these days.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
![](/assets/img/avatar_default.png "\\"Talpey, Thomas\"){kind=avatar}