mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-09-04 01:49:36 +00:00
![Benjamin Coddington](/assets/img/avatar_default.png)
NFS would enjoy the ability to modify the behavior of the NLM client's unlock RPC task in order to delay the transmission of the unlock until IO that was submitted under that lock has completed. This ability can ensure that the NLM client will always complete the transmission of an unlock even if the waiting caller has been interrupted with fatal signal. For this purpose, a pointer to a struct nlmclnt_operations can be assigned in a nfs_module's nfs_rpc_ops that will install those nlmclnt_operations on the nlm_host. The struct nlmclnt_operations defines three callback operations that will be used in a following patch: nlmclnt_alloc_call - used to call back after a successful allocation of a struct nlm_rqst in nlmclnt_proc(). nlmclnt_unlock_prepare - used to call back during NLM unlock's rpc_call_prepare. The NLM client defers calling rpc_call_start() until this callback returns false. nlmclnt_release_call - used to call back when the NLM client's struct nlm_rqst is freed. Signed-off-by: Benjamin Coddington <bcodding@redhat.com> Reviewed-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
302 lines
7.5 KiB
C
302 lines
7.5 KiB
C
/*
|
|
* linux/fs/lockd/clntlock.c
|
|
*
|
|
* Lock handling for the client side NLM implementation
|
|
*
|
|
* Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
|
|
*/
|
|
|
|
#include <linux/module.h>
|
|
#include <linux/types.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/time.h>
|
|
#include <linux/nfs_fs.h>
|
|
#include <linux/sunrpc/addr.h>
|
|
#include <linux/sunrpc/svc.h>
|
|
#include <linux/lockd/lockd.h>
|
|
#include <linux/kthread.h>
|
|
|
|
#define NLMDBG_FACILITY NLMDBG_CLIENT
|
|
|
|
/*
|
|
* Local function prototypes
|
|
*/
|
|
static int reclaimer(void *ptr);
|
|
|
|
/*
|
|
* The following functions handle blocking and granting from the
|
|
* client perspective.
|
|
*/
|
|
|
|
/*
|
|
* This is the representation of a blocked client lock.
|
|
*/
|
|
struct nlm_wait {
|
|
struct list_head b_list; /* linked list */
|
|
wait_queue_head_t b_wait; /* where to wait on */
|
|
struct nlm_host * b_host;
|
|
struct file_lock * b_lock; /* local file lock */
|
|
unsigned short b_reclaim; /* got to reclaim lock */
|
|
__be32 b_status; /* grant callback status */
|
|
};
|
|
|
|
static LIST_HEAD(nlm_blocked);
|
|
static DEFINE_SPINLOCK(nlm_blocked_lock);
|
|
|
|
/**
|
|
* nlmclnt_init - Set up per-NFS mount point lockd data structures
|
|
* @nlm_init: pointer to arguments structure
|
|
*
|
|
* Returns pointer to an appropriate nlm_host struct,
|
|
* or an ERR_PTR value.
|
|
*/
|
|
struct nlm_host *nlmclnt_init(const struct nlmclnt_initdata *nlm_init)
|
|
{
|
|
struct nlm_host *host;
|
|
u32 nlm_version = (nlm_init->nfs_version == 2) ? 1 : 4;
|
|
int status;
|
|
|
|
status = lockd_up(nlm_init->net);
|
|
if (status < 0)
|
|
return ERR_PTR(status);
|
|
|
|
host = nlmclnt_lookup_host(nlm_init->address, nlm_init->addrlen,
|
|
nlm_init->protocol, nlm_version,
|
|
nlm_init->hostname, nlm_init->noresvport,
|
|
nlm_init->net);
|
|
if (host == NULL)
|
|
goto out_nohost;
|
|
if (host->h_rpcclnt == NULL && nlm_bind_host(host) == NULL)
|
|
goto out_nobind;
|
|
|
|
host->h_nlmclnt_ops = nlm_init->nlmclnt_ops;
|
|
return host;
|
|
out_nobind:
|
|
nlmclnt_release_host(host);
|
|
out_nohost:
|
|
lockd_down(nlm_init->net);
|
|
return ERR_PTR(-ENOLCK);
|
|
}
|
|
EXPORT_SYMBOL_GPL(nlmclnt_init);
|
|
|
|
/**
|
|
* nlmclnt_done - Release resources allocated by nlmclnt_init()
|
|
* @host: nlm_host structure reserved by nlmclnt_init()
|
|
*
|
|
*/
|
|
void nlmclnt_done(struct nlm_host *host)
|
|
{
|
|
struct net *net = host->net;
|
|
|
|
nlmclnt_release_host(host);
|
|
lockd_down(net);
|
|
}
|
|
EXPORT_SYMBOL_GPL(nlmclnt_done);
|
|
|
|
/*
|
|
* Queue up a lock for blocking so that the GRANTED request can see it
|
|
*/
|
|
struct nlm_wait *nlmclnt_prepare_block(struct nlm_host *host, struct file_lock *fl)
|
|
{
|
|
struct nlm_wait *block;
|
|
|
|
block = kmalloc(sizeof(*block), GFP_KERNEL);
|
|
if (block != NULL) {
|
|
block->b_host = host;
|
|
block->b_lock = fl;
|
|
init_waitqueue_head(&block->b_wait);
|
|
block->b_status = nlm_lck_blocked;
|
|
|
|
spin_lock(&nlm_blocked_lock);
|
|
list_add(&block->b_list, &nlm_blocked);
|
|
spin_unlock(&nlm_blocked_lock);
|
|
}
|
|
return block;
|
|
}
|
|
|
|
void nlmclnt_finish_block(struct nlm_wait *block)
|
|
{
|
|
if (block == NULL)
|
|
return;
|
|
spin_lock(&nlm_blocked_lock);
|
|
list_del(&block->b_list);
|
|
spin_unlock(&nlm_blocked_lock);
|
|
kfree(block);
|
|
}
|
|
|
|
/*
|
|
* Block on a lock
|
|
*/
|
|
int nlmclnt_block(struct nlm_wait *block, struct nlm_rqst *req, long timeout)
|
|
{
|
|
long ret;
|
|
|
|
/* A borken server might ask us to block even if we didn't
|
|
* request it. Just say no!
|
|
*/
|
|
if (block == NULL)
|
|
return -EAGAIN;
|
|
|
|
/* Go to sleep waiting for GRANT callback. Some servers seem
|
|
* to lose callbacks, however, so we're going to poll from
|
|
* time to time just to make sure.
|
|
*
|
|
* For now, the retry frequency is pretty high; normally
|
|
* a 1 minute timeout would do. See the comment before
|
|
* nlmclnt_lock for an explanation.
|
|
*/
|
|
ret = wait_event_interruptible_timeout(block->b_wait,
|
|
block->b_status != nlm_lck_blocked,
|
|
timeout);
|
|
if (ret < 0)
|
|
return -ERESTARTSYS;
|
|
/* Reset the lock status after a server reboot so we resend */
|
|
if (block->b_status == nlm_lck_denied_grace_period)
|
|
block->b_status = nlm_lck_blocked;
|
|
req->a_res.status = block->b_status;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* The server lockd has called us back to tell us the lock was granted
|
|
*/
|
|
__be32 nlmclnt_grant(const struct sockaddr *addr, const struct nlm_lock *lock)
|
|
{
|
|
const struct file_lock *fl = &lock->fl;
|
|
const struct nfs_fh *fh = &lock->fh;
|
|
struct nlm_wait *block;
|
|
__be32 res = nlm_lck_denied;
|
|
|
|
/*
|
|
* Look up blocked request based on arguments.
|
|
* Warning: must not use cookie to match it!
|
|
*/
|
|
spin_lock(&nlm_blocked_lock);
|
|
list_for_each_entry(block, &nlm_blocked, b_list) {
|
|
struct file_lock *fl_blocked = block->b_lock;
|
|
|
|
if (fl_blocked->fl_start != fl->fl_start)
|
|
continue;
|
|
if (fl_blocked->fl_end != fl->fl_end)
|
|
continue;
|
|
/*
|
|
* Careful! The NLM server will return the 32-bit "pid" that
|
|
* we put on the wire: in this case the lockowner "pid".
|
|
*/
|
|
if (fl_blocked->fl_u.nfs_fl.owner->pid != lock->svid)
|
|
continue;
|
|
if (!rpc_cmp_addr(nlm_addr(block->b_host), addr))
|
|
continue;
|
|
if (nfs_compare_fh(NFS_FH(file_inode(fl_blocked->fl_file)) ,fh) != 0)
|
|
continue;
|
|
/* Alright, we found a lock. Set the return status
|
|
* and wake up the caller
|
|
*/
|
|
block->b_status = nlm_granted;
|
|
wake_up(&block->b_wait);
|
|
res = nlm_granted;
|
|
}
|
|
spin_unlock(&nlm_blocked_lock);
|
|
return res;
|
|
}
|
|
|
|
/*
|
|
* The following procedures deal with the recovery of locks after a
|
|
* server crash.
|
|
*/
|
|
|
|
/*
|
|
* Reclaim all locks on server host. We do this by spawning a separate
|
|
* reclaimer thread.
|
|
*/
|
|
void
|
|
nlmclnt_recovery(struct nlm_host *host)
|
|
{
|
|
struct task_struct *task;
|
|
|
|
if (!host->h_reclaiming++) {
|
|
nlm_get_host(host);
|
|
task = kthread_run(reclaimer, host, "%s-reclaim", host->h_name);
|
|
if (IS_ERR(task))
|
|
printk(KERN_ERR "lockd: unable to spawn reclaimer "
|
|
"thread. Locks for %s won't be reclaimed! "
|
|
"(%ld)\n", host->h_name, PTR_ERR(task));
|
|
}
|
|
}
|
|
|
|
static int
|
|
reclaimer(void *ptr)
|
|
{
|
|
struct nlm_host *host = (struct nlm_host *) ptr;
|
|
struct nlm_wait *block;
|
|
struct nlm_rqst *req;
|
|
struct file_lock *fl, *next;
|
|
u32 nsmstate;
|
|
struct net *net = host->net;
|
|
|
|
req = kmalloc(sizeof(*req), GFP_KERNEL);
|
|
if (!req) {
|
|
printk(KERN_ERR "lockd: reclaimer unable to alloc memory."
|
|
" Locks for %s won't be reclaimed!\n",
|
|
host->h_name);
|
|
return 0;
|
|
}
|
|
|
|
allow_signal(SIGKILL);
|
|
|
|
down_write(&host->h_rwsem);
|
|
lockd_up(net); /* note: this cannot fail as lockd is already running */
|
|
|
|
dprintk("lockd: reclaiming locks for host %s\n", host->h_name);
|
|
|
|
restart:
|
|
nsmstate = host->h_nsmstate;
|
|
|
|
/* Force a portmap getport - the peer's lockd will
|
|
* most likely end up on a different port.
|
|
*/
|
|
host->h_nextrebind = jiffies;
|
|
nlm_rebind_host(host);
|
|
|
|
/* First, reclaim all locks that have been granted. */
|
|
list_splice_init(&host->h_granted, &host->h_reclaim);
|
|
list_for_each_entry_safe(fl, next, &host->h_reclaim, fl_u.nfs_fl.list) {
|
|
list_del_init(&fl->fl_u.nfs_fl.list);
|
|
|
|
/*
|
|
* sending this thread a SIGKILL will result in any unreclaimed
|
|
* locks being removed from the h_granted list. This means that
|
|
* the kernel will not attempt to reclaim them again if a new
|
|
* reclaimer thread is spawned for this host.
|
|
*/
|
|
if (signalled())
|
|
continue;
|
|
if (nlmclnt_reclaim(host, fl, req) != 0)
|
|
continue;
|
|
list_add_tail(&fl->fl_u.nfs_fl.list, &host->h_granted);
|
|
if (host->h_nsmstate != nsmstate) {
|
|
/* Argh! The server rebooted again! */
|
|
goto restart;
|
|
}
|
|
}
|
|
|
|
host->h_reclaiming = 0;
|
|
up_write(&host->h_rwsem);
|
|
dprintk("NLM: done reclaiming locks for host %s\n", host->h_name);
|
|
|
|
/* Now, wake up all processes that sleep on a blocked lock */
|
|
spin_lock(&nlm_blocked_lock);
|
|
list_for_each_entry(block, &nlm_blocked, b_list) {
|
|
if (block->b_host == host) {
|
|
block->b_status = nlm_lck_denied_grace_period;
|
|
wake_up(&block->b_wait);
|
|
}
|
|
}
|
|
spin_unlock(&nlm_blocked_lock);
|
|
|
|
/* Release host handle after use */
|
|
nlmclnt_release_host(host);
|
|
lockd_down(net);
|
|
kfree(req);
|
|
return 0;
|
|
}
|