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NLM/NFS: Use cached nlm_host when calling nlmclnt_proc()

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Now that each NFS mount point caches its own nlm_host structure, it can be
passed to nlmclnt_proc() for each lock request.  By pinning an nlm_host for
each mount point, we trade the overhead of looking up or creating a fresh
nlm_host struct during every NLM procedure call for a little extra memory.

We also restrict the nlmclnt_proc symbol to limit the use of this call to
in-tree modules.

Note that nlm_lookup_host() (just removed from the client's per-request
NLM processing) could also trigger an nlm_host garbage collection.  Now
client-side nlm_host garbage collection occurs only during NFS mount
processing.  Since the NFS client now holds a reference on these nlm_host
structures, they wouldn't have been affected by garbage collection
anyway.

Given that nlm_lookup_host() reorders the global nlm_host chain after
every successful lookup, and that a garbage collection could be triggered
during the call, we've removed a significant amount of per-NLM-request
CPU processing overhead.

Sidebar: there are only a few remaining references to the internals of
NFS inodes in the client-side NLM code.  The only references I found are
related to extracting or comparing the inode's file handle via NFS_FH().
One is in nlmclnt_grant(); the other is in nlmclnt_setlockargs().

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
This commit is contained in:
Chuck Lever 2008-01-11 17:09:59 -05:00 committed by Trond Myklebust
parent 9289e7f91a
commit 1093a60ef3
4 changed files with 18 additions and 26 deletions
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33
fs/lockd/clntproc.c
View file

@ -145,34 +145,21 @@ static void nlmclnt_release_lockargs(struct nlm_rqst *req)
BUG_ON(req->a_args.lock.fl.fl_ops != NULL);
}
/*
* This is the main entry point for the NLM client.
/**
* nlmclnt_proc - Perform a single client-side lock request
* @host: address of a valid nlm_host context representing the NLM server
* @cmd: fcntl-style file lock operation to perform
* @fl: address of arguments for the lock operation
*
*/
int
nlmclnt_proc(struct inode *inode, int cmd, struct file_lock *fl)
int nlmclnt_proc(struct nlm_host *host, int cmd, struct file_lock *fl)
{
struct rpc_clnt *client = NFS_CLIENT(inode);
struct sockaddr_in addr;
struct nfs_server *nfssrv = NFS_SERVER(inode);
struct nlm_host *host;
struct nlm_rqst *call;
sigset_t oldset;
unsigned long flags;
int status, vers;
vers = (NFS_PROTO(inode)->version == 3) ? 4 : 1;
if (NFS_PROTO(inode)->version > 3) {
printk(KERN_NOTICE "NFSv4 file locking not implemented!\n");
return -ENOLCK;
}
rpc_peeraddr(client, (struct sockaddr *) &addr, sizeof(addr));
host = nlmclnt_lookup_host(&addr, client->cl_xprt->prot, vers,
nfssrv->nfs_client->cl_hostname,
strlen(nfssrv->nfs_client->cl_hostname));
if (host == NULL)
return -ENOLCK;
int status;
nlm_get_host(host);
call = nlm_alloc_call(host);
if (call == NULL)
return -ENOMEM;
@ -219,7 +206,7 @@ nlmclnt_proc(struct inode *inode, int cmd, struct file_lock *fl)
dprintk("lockd: clnt proc returns %d\n", status);
return status;
}
EXPORT_SYMBOL(nlmclnt_proc);
EXPORT_SYMBOL_GPL(nlmclnt_proc);
/*
* Allocate an NLM RPC call struct

4
fs/nfs/nfs3proc.c
View file

@ -767,7 +767,9 @@ static void nfs3_proc_commit_setup(struct nfs_write_data *data, struct rpc_messa
static int
nfs3_proc_lock(struct file *filp, int cmd, struct file_lock *fl)
{
return nlmclnt_proc(filp->f_path.dentry->d_inode, cmd, fl);
struct inode *inode = filp->f_path.dentry->d_inode;
return nlmclnt_proc(NFS_SERVER(inode)->nlm_host, cmd, fl);
}
const struct nfs_rpc_ops nfs_v3_clientops = {

4
fs/nfs/proc.c
View file

@ -593,7 +593,9 @@ nfs_proc_commit_setup(struct nfs_write_data *data, struct rpc_message *msg)
static int
nfs_proc_lock(struct file *filp, int cmd, struct file_lock *fl)
{
return nlmclnt_proc(filp->f_path.dentry->d_inode, cmd, fl);
struct inode *inode = filp->f_path.dentry->d_inode;
return nlmclnt_proc(NFS_SERVER(inode)->nlm_host, cmd, fl);
}

3
include/linux/lockd/bind.h
View file

@ -42,7 +42,8 @@ extern struct nlm_host *nlmclnt_init(const char *server_name,
u32 nfs_version);
extern void nlmclnt_done(struct nlm_host *host);
extern int nlmclnt_proc(struct inode *, int, struct file_lock *);
extern int nlmclnt_proc(struct nlm_host *host, int cmd,
struct file_lock *fl);
extern int lockd_up(int proto);
extern void lockd_down(void);