Commit Graph

73 Commits

Author SHA1 Message Date
NeilBrown
7d317f2c9f [PATCH] knfsd: Get rid of 'inplace' sunrpc caches
These were an unnecessary wart.  Also only have one 'DefineSimpleCache..'
instead of two.

Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-27 08:44:41 -08:00
NeilBrown
efc36aa560 [PATCH] knfsd: Change the store of auth_domains to not be a 'cache'
The 'auth_domain's are simply handles on internal data structures.  They do
not cache information from user-space, and forcing them into the mold of a
'cache' misrepresents their true nature and causes confusion.

Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-27 08:44:41 -08:00
Trond Myklebust
1ebbe2b200 Merge branch 'linus' 2006-03-23 23:44:19 -05:00
Ingo Molnar
57b47a53ec [NET]: sem2mutex part 2
Semaphore to mutex conversion.

The conversion was generated via scripts, and the result was validated
automatically via a script as well.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-20 22:35:41 -08:00
J. Bruce Fields
eaa82edf20 SUNRPC,RPCSEC_GSS: fix krb5 sequence numbers.
Use a spinlock to ensure unique sequence numbers when creating krb5 gss tokens.

Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-03-20 23:24:04 -05:00
Trond Myklebust
5428154827 SUNRPC: Fix a 'Busy inodes' error in rpc_pipefs
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-03-20 13:44:49 -05:00
Chuck Lever
dead28da8e SUNRPC: eliminate rpc_call()
Clean-up: replace rpc_call() helper with direct call to rpc_call_sync.

This makes NFSv2 and NFSv3 synchronous calls more computationally
efficient, and reduces stack consumption in functions that used to
invoke rpc_call more than once.

Test plan:
Compile kernel with CONFIG_NFS enabled.  Connectathon on NFS version 2,
version 3, and version 4 mount points.

Signed-off-by: Chuck Lever <cel@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-03-20 13:44:23 -05:00
Chuck Lever
cc0175c1dc SUNRPC: display human-readable procedure name in rpc_iostats output
Add fields to the rpc_procinfo struct that allow the display of a
human-readable name for each procedure in the rpc_iostats output.

Also fix it so that the NFSv4 stats are broken up correctly by
sub-procedure number.  NFSv4 uses only two real RPC procedures:
NULL, and COMPOUND.

Test plan:
Mount with NFSv2, NFSv3, and NFSv4, and do "cat /proc/self/mountstats".

Signed-off-by: Chuck Lever <cel@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-03-20 13:44:22 -05:00
Chuck Lever
11c556b3d8 SUNRPC: provide a mechanism for collecting stats in the RPC client
Add a simple mechanism for collecting stats in the RPC client.  Stats are
tabulated during xprt_release.  Note that per_cpu shenanigans are not
required here because the RPC client already serializes on the transport
write lock.

Test plan:
Compile kernel with CONFIG_NFS enabled.  Basic performance regression
testing with high-speed networking and high performance server.

Signed-off-by: Chuck Lever <cel@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-03-20 13:44:22 -05:00
Chuck Lever
ef759a2e54 SUNRPC: introduce per-task RPC iostats
Account for various things that occur while an RPC task is executed.
Separate timers for RPC round trip and RPC execution time show how
long RPC requests wait in queue before being sent.  Eventually these
will be accumulated at xprt_release time in one place where they can
be viewed from userland.

Test plan:
Compile kernel with CONFIG_NFS enabled.

Signed-off-by: Chuck Lever <cel@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-03-20 13:44:17 -05:00
Chuck Lever
262ca07de4 SUNRPC: add a handful of per-xprt counters
Monitor generic transport events.  Add a transport switch callout to
format transport counters for export to user-land.

Test plan:
Compile kernel with CONFIG_NFS enabled.

Signed-off-by: Chuck Lever <cel@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-03-20 13:44:16 -05:00
Chuck Lever
e19b63dafd SUNRPC: track length of RPC wait queues
RPC wait queue length will eventually be exported to userland via the RPC
iostats interface.

Test plan:
Compile kernel with CONFIG_NFS enabled.

Signed-off-by: Chuck Lever <cel@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-03-20 13:44:15 -05:00
Trond Myklebust
24c5d9d7ea SUNRPC: Run rpci->queue_timeout on the rpciod workqueue instead of generic
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-03-20 13:44:08 -05:00
Trond Myklebust
00b464debf SUNRPC: Remove obsolete rpcauth #defines
RPCAUTH_CRED_LOCKED, and RPC_AUTH_PROC_CREDS are unused. Kill them.

 Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-02-01 12:52:25 -05:00
Trond Myklebust
fba3bad488 SUNRPC: Move upcall out of auth->au_ops->crcreate()
This fixes a bug whereby if two processes try to look up the same auth_gss
 credential, they may end up creating two creds, and triggering two upcalls
 because the upcall is performed before the credential is added to the
 credcache.

 Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-02-01 12:52:25 -05:00
Trond Myklebust
8a3177604b SUNRPC: Fix a lock recursion in the auth_gss downcall
When we look up a new cred in the auth_gss downcall so that we can stuff
 the credcache, we do not want that lookup to queue up an upcall in order
 to initialise it. To do an upcall here not only redundant, but since we
 are already holding the inode->i_mutex, it will trigger a lock recursion.

 This patch allows rpcauth cache searches to indicate that they can cope
 with uninitialised credentials.

 Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-02-01 12:52:23 -05:00
J. Bruce Fields
1918e34138 [PATCH] svcrpc: save and restore the daddr field when request deferred
The server code currently keeps track of the destination address on every
request so that it can reply using the same address.  However we forget to do
that in the case of a deferred request.  Remedy this oversight.  >From folks
at PolyServe.

Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-18 19:20:24 -08:00
J. Bruce Fields
9eed129bbd SUNRPC: Update the spkm3 code to use the make_checksum interface
Also update the tokenlen calculations to accomodate g_token_size().

 Signed-off-by: Andy Adamson <andros@citi.umich.edu>
 Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
 Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-01-06 14:58:59 -05:00
Trond Myklebust
632e3bdc50 SUNRPC: Ensure client closes the socket when server initiates a close
If the server decides to close the RPC socket, we currently don't actually
 respond until either another RPC call is scheduled, or until xprt_autoclose()
 gets called by the socket expiry timer (which may be up to 5 minutes
 later).

 This patch ensures that xprt_autoclose() is called much sooner if the
 server closes the socket.

 Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-01-06 14:58:57 -05:00
Chuck Lever
f518e35aec SUNRPC: get rid of cl_chatty
Clean up: Every ULP that uses the in-kernel RPC client, except the NLM
 client, sets cl_chatty.  There's no reason why NLM shouldn't set it, so
 just get rid of cl_chatty and always be verbose.

 Test-plan:
 Compile with CONFIG_NFS enabled.

 Signed-off-by: Chuck Lever <cel@netapp.com>
 Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-01-06 14:58:56 -05:00
Chuck Lever
922004120b SUNRPC: transport switch API for setting port number
At some point, transport endpoint addresses will no longer be IPv4.  To hide
 the structure of the rpc_xprt's address field from ULPs and port mappers,
 add an API for setting the port number during an RPC bind operation.

 Test-plan:
 Destructive testing (unplugging the network temporarily).  Connectathon
 with UDP and TCP.  NFSv2/3 and NFSv4 mounting should be carefully checked.
 Probably need to rig a server where certain services aren't running, or
 that returns an error for some typical operation.

 Signed-off-by: Chuck Lever <cel@netapp.com>
 Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-01-06 14:58:56 -05:00
Chuck Lever
35f5a422ce SUNRPC: new interface to force an RPC rebind
We'd like to hide fields in rpc_xprt and rpc_clnt from upper layer protocols.
 Start by creating an API to force RPC rebind, replacing logic that simply
 sets cl_port to zero.

 Test-plan:
 Destructive testing (unplugging the network temporarily).  Connectathon
 with UDP and TCP.  NFSv2/3 and NFSv4 mounting should be carefully checked.
 Probably need to rig a server where certain services aren't running, or
 that returns an error for some typical operation.

 Signed-off-by: Chuck Lever <cel@netapp.com>
 Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-01-06 14:58:56 -05:00
Chuck Lever
0210714834 SUNRPC: switchable buffer allocation
Add RPC client transport switch support for replacing buffer management
 on a per-transport basis.

 In the current IPv4 socket transport implementation, RPC buffers are
 allocated as needed for each RPC message that is sent.  Some transport
 implementations may choose to use pre-allocated buffers for encoding,
 sending, receiving, and unmarshalling RPC messages, however.  For
 transports capable of direct data placement, the buffers can be carved
 out of a pre-registered area of memory rather than from a slab cache.

 Test-plan:
 Millions of fsx operations.  Performance characterization with "sio" and
 "iozone".  Use oprofile and other tools to look for significant regression
 in CPU utilization.

 Signed-off-by: Chuck Lever <cel@netapp.com>
 Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-01-06 14:58:55 -05:00
Adrian Bunk
fb459f45f7 SUNRPC: net/sunrpc/xdr.c: remove xdr_decode_string()
This patch removes ths unused function xdr_decode_string().

Signed-off-by: Adrian Bunk <bunk@stusta.de>
Acked-by: Neil Brown <neilb@suse.de>
Acked-by: Charles Lever <Charles.Lever@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-01-06 14:58:53 -05:00
Chuck Lever
40859d7ee6 NFS: support large reads and writes on the wire
Most NFS server implementations allow up to 64KB reads and writes on the
 wire.  The Solaris NFS server allows up to a megabyte, for instance.

 Now the Linux NFS client supports transfer sizes up to 1MB, too.  This will
 help reduce protocol and context switch overhead on read/write intensive NFS
 workloads, and support larger atomic read and write operations on servers
 that support them.

 Test-plan:
 Connectathon and iozone on mount point with wsize=rsize>32768 over TCP.
 Tests with NFS over UDP to verify the maximum RPC payload size cap.

 Signed-off-by: Chuck Lever <cel@netapp.com>
 Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-01-06 14:58:49 -05:00
Trond Myklebust
44c288732f NFSv4: stateful NFSv4 RPC call interface
The NFSv4 model requires us to complete all RPC calls that might
 establish state on the server whether or not the user wants to
 interrupt it. We may also need to schedule new work (including
 new RPC calls) in order to cancel the new state.

 The asynchronous RPC model will allow us to ensure that RPC calls
 always complete, but in order to allow for "synchronous" RPC, we
 want to add the ability to wait for completion.
 The waits are, of course, interruptible.

 Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-01-06 14:58:40 -05:00
Trond Myklebust
4ce70ada1f SUNRPC: Further cleanups
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-01-06 14:58:40 -05:00
Trond Myklebust
963d8fe533 RPC: Clean up RPC task structure
Shrink the RPC task structure. Instead of storing separate pointers
 for task->tk_exit and task->tk_release, put them in a structure.

 Also pass the user data pointer as a parameter instead of passing it via
 task->tk_calldata. This enables us to nest callbacks.

 Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-01-06 14:58:39 -05:00
Trond Myklebust
abbcf28f23 SUNRPC: Yet more RPC cleanups
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-01-06 14:58:39 -05:00
NeilBrown
0ba7536d5d [PATCH] knfsd: Fix some minor sign problems in nfsd/xdr
There are a couple of tests which could possibly be confused by extremely
large numbers appearing in 'xdr' packets.  I think the closest to an exploit
you could get would be writing random data from a free page into a file - i.e.
 leak data out of kernel space.

I'm fairly sure they cannot be used for remote compromise.

Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-07 07:53:48 -08:00
J. Bruce Fields
a0857d03b2 RPCSEC_GSS: krb5 cleanup
Remove some senseless wrappers.

 Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
 Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2005-10-18 23:19:47 -07:00
J. Bruce Fields
00fd6e1425 RPCSEC_GSS remove all qop parameters
Not only are the qop parameters that are passed around throughout the gssapi
 unused by any currently implemented mechanism, but there appears to be some
 doubt as to whether they will ever be used.  Let's just kill them off for now.

 Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
 Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2005-10-18 23:19:47 -07:00
J. Bruce Fields
14ae162c24 RPCSEC_GSS: Add support for privacy to krb5 rpcsec_gss mechanism.
Add support for privacy to the krb5 rpcsec_gss mechanism.

 Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
 Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2005-10-18 23:19:46 -07:00
J. Bruce Fields
bfa91516b5 RPCSEC_GSS: krb5 pre-privacy cleanup
The code this was originally derived from processed wrap and mic tokens using
 the same functions.  This required some contortions, and more would be required
 with the addition of xdr_buf's, so it's better to separate out the two code
 paths.

 In preparation for adding privacy support, remove the last vestiges of the
 old wrap token code.

 Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
 Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2005-10-18 23:19:45 -07:00
J. Bruce Fields
24b2605bec RPCSEC_GSS: cleanup au_rslack calculation
Various xdr encode routines use au_rslack to guess where the reply argument
 will end up, so we can set up the xdr_buf to recieve data into the right place
 for zero copy.

 Currently we calculate the au_rslack estimate when we check the verifier.
 Normally this only depends on the verifier size.  In the integrity case we add
 a few bytes to allow for a length and sequence number.

 It's a bit simpler to calculate only the verifier size when we check the
 verifier, and delay the full calculation till we unwrap.

 Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
 Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2005-10-18 23:19:44 -07:00
J. Bruce Fields
ead5e1c26f SUNRPC: Provide a callback to allow free pages allocated during xdr encoding
For privacy, we need to allocate pages to store the encrypted data (passed
 in pages can't be used without the risk of corrupting data in the page cache).
 So we need a way to free that memory after the request has been transmitted.

 Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
 Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2005-10-18 23:19:43 -07:00
J. Bruce Fields
293f1eb551 SUNRPC: Add support for privacy to generic gss-api code.
Add support for privacy to generic gss-api code.  This is dead code until we
 have both a mechanism that supports privacy and code in the client or server
 that uses it.

 Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
 Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2005-10-18 23:19:42 -07:00
Trond Myklebust
5e5ce5be6f RPC: allow call_encode() to delay transmission of an RPC call.
Currently, call_encode will cause the entire RPC call to abort if it returns
 an error. This is unnecessarily rigid, and gets in the way of attempts
 to allow the NFSv4 layer to order RPC calls that carry sequence ids.

 Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2005-10-18 14:20:11 -07:00
Trond Myklebust
f134585a73 Revert "[PATCH] RPC,NFS: new rpc_pipefs patch"
This reverts 17f4e6febca160a9f9dd4bdece9784577a2f4524 commit.
2005-09-23 12:39:00 -04:00
Christoph Hellwig
278c995c8a [PATCH] RPC,NFS: new rpc_pipefs patch
Currently rpc_mkdir/rpc_rmdir and rpc_mkpipe/mk_unlink have an API that's
 a little unfortunate.  They take a path relative to the rpc_pipefs root and
 thus need to perform a full lookup.  If you look at debugfs or usbfs they
 always store the dentry for directories they created and thus can pass in
 a dentry + single pathname component pair into their equivalents of the
 above functions.

 And in fact rpc_pipefs actually stores a dentry for all but one component so
 this change not only simplifies the core rpc_pipe code but also the callers.

 Unfortuntately this code path is only used by the NFS4 idmapper and
 AUTH_GSSAPI for which I don't have a test enviroment.  Could someone give
 it a spin?  It's the last bit needed before we can rework the
 lookup_hash API

 Signed-off-by: Christoph Hellwig <hch@lst.de>
 Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2005-09-23 12:38:57 -04:00
Chuck Lever
470056c288 [PATCH] RPC: rationalize set_buffer_size
In fact, ->set_buffer_size should be completely functionless for non-UDP.

 Test-plan:
 Check socket buffer size on UDP sockets over time.

 Signed-off-by: Chuck Lever <cel@netapp.com>
 Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2005-09-23 12:38:55 -04:00
Chuck Lever
03bf4b707e [PATCH] RPC: parametrize various transport connect timeouts
Each transport implementation can now set unique bind, connect,
 reestablishment, and idle timeout values.  These are variables,
 allowing the values to be modified dynamically.  This permits
 exponential backoff of any of these values, for instance.

 As an example, we implement exponential backoff for the connection
 reestablishment timeout.

 Test-plan:
 Destructive testing (unplugging the network temporarily).  Connectathon
 with UDP and TCP.

 Signed-off-by: Chuck Lever <cel@netapp.com>
 Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2005-09-23 12:38:53 -04:00
Chuck Lever
529b33c6db [PATCH] RPC: allow RPC client's port range to be adjustable
Select an RPC client source port between 650 and 1023 instead of between
 1 and 800.  The old range conflicts with a number of network services.
 Provide sysctls to allow admins to select a different port range.

 Note that this doesn't affect user-level RPC library behavior, which
 still uses 1 to 800.

 Based on a suggestion by Olaf Kirch <okir@suse.de>.

 Test-plan:
 Repeated mount and unmount.  Destructive testing.  Idle timeouts.

 Signed-off-by: Chuck Lever <cel@netapp.com>
 Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2005-09-23 12:38:50 -04:00
Chuck Lever
555ee3af16 [PATCH] RPC: clean up after nocong was removed
Clean-up:  Move some macros that are specific to the Van Jacobson
 implementation into xprt.c.  Get rid of the cong_wait field in
 rpc_xprt, which is no longer used.  Get rid of xprt_clear_backlog.

 Test-plan:
 Compile with CONFIG_NFS enabled.

 Signed-off-by: Chuck Lever <cel@netapp.com>
 Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2005-09-23 12:38:48 -04:00
Chuck Lever
ed63c00370 [PATCH] RPC: remove xprt->nocong
Get rid of the "xprt->nocong" variable.

 Test-plan:
 Use WAN simulation to cause sporadic bursty packet loss with UDP mounts.
 Look for significant regression in performance or client stability.

 Signed-off-by: Chuck Lever <cel@netapp.com>
 Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2005-09-23 12:38:47 -04:00
Chuck Lever
a58dd398f5 [PATCH] RPC: add a release_rqst callout to the RPC transport switch
The final place where congestion control state is adjusted is in
 xprt_release, where each request is finally released.  Add a callout
 there to allow transports to perform additional processing when a
 request is about to be released.

 Test-plan:
 Use WAN simulation to cause sporadic bursty packet loss.  Look for significant
 regression in performance or client stability.

 Signed-off-by: Chuck Lever <cel@netapp.com>
 Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2005-09-23 12:38:45 -04:00
Chuck Lever
1570c1e41e [PATCH] RPC: add generic interface for adjusting the congestion window
A new interface that allows transports to adjust their congestion window
 using the Van Jacobson implementation in xprt.c is provided.

 Test-plan:
 Use WAN simulation to cause sporadic bursty packet loss.  Look for
 significant regression in performance or client stability.

 Signed-off-by: Chuck Lever <cel@netapp.com>
 Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2005-09-23 12:38:43 -04:00
Chuck Lever
46c0ee8bc4 [PATCH] RPC: separate xprt_timer implementations
Allow transports to hook the retransmit timer interrupt.  Some transports
 calculate their congestion window here so that a retransmit timeout has
 immediate effect on the congestion window.

 Test-plan:
 Use WAN simulation to cause sporadic bursty packet loss.  Look for significant
 regression in performance or client stability.

 Signed-off-by: Chuck Lever <cel@netapp.com>
 Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2005-09-23 12:38:41 -04:00
Chuck Lever
49e9a89086 [PATCH] RPC: expose API for serializing access to RPC transports
The next method we abstract is the one that releases a transport,
 allowing another task to have access to the transport.

 Again, one generic version of this is provided for transports that
 don't need the RPC client to perform congestion control, and one
 version is for transports that can use the original Van Jacobson
 implementation in xprt.c.

 Test-plan:
 Use WAN simulation to cause sporadic bursty packet loss.  Look for
 significant regression in performance or client stability.

 Signed-off-by: Chuck Lever <cel@netapp.com>
 Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2005-09-23 12:38:40 -04:00
Chuck Lever
12a804698b [PATCH] RPC: expose API for serializing access to RPC transports
The next several patches introduce an API that allows transports to
 choose whether the RPC client provides congestion control or whether
 the transport itself provides it.

 The first method we abstract is the one that serializes access to the
 RPC transport to prevent the bytes from different requests from mingling
 together.  This method provides proper request serialization and the
 opportunity to prevent new requests from being started because the
 transport is congested.

 The normal situation is for the transport to handle congestion control
 itself.  Although NFS over UDP was first, it has been recognized after
 years of experience that having the transport provide congestion control
 is much better than doing it in the RPC client.  Thus TCP, and probably
 every future transport implementation, will use the default method,
 xprt_lock_write, provided in xprt.c, which does not provide any kind
 of congestion control.  UDP can continue using the xprt.c-provided
 Van Jacobson congestion avoidance implementation.

 Test-plan:
 Use WAN simulation to cause sporadic bursty packet loss.  Look for significant
 regression in performance or client stability.

 Signed-off-by: Chuck Lever <cel@netapp.com>
 Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2005-09-23 12:38:38 -04:00