Linux-2.6.12-rc2v2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 686 insertions, 0 deletions

diff --git a/fs/lockd/svclock.c b/fs/lockd/svclock.c
new file mode 100644
index 000000000000..49f959796b66
--- /dev/null
+++ b/fs/lockd/svclock.c
@@ -0,0 +1,686 @@
+/*
+ * linux/fs/lockd/svclock.c
+ *
+ * Handling of server-side locks, mostly of the blocked variety.
+ * This is the ugliest part of lockd because we tread on very thin ice.
+ * GRANT and CANCEL calls may get stuck, meet in mid-flight, etc.
+ * IMNSHO introducing the grant callback into the NLM protocol was one
+ * of the worst ideas Sun ever had. Except maybe for the idea of doing
+ * NFS file locking at all.
+ *
+ * I'm trying hard to avoid race conditions by protecting most accesses
+ * to a file's list of blocked locks through a semaphore. The global
+ * list of blocked locks is not protected in this fashion however.
+ * Therefore, some functions (such as the RPC callback for the async grant
+ * call) move blocked locks towards the head of the list *while some other
+ * process might be traversing it*. This should not be a problem in
+ * practice, because this will only cause functions traversing the list
+ * to visit some blocks twice.
+ *
+ * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
+ */
+
+#include <linux/config.h>
+#include <linux/types.h>
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/smp_lock.h>
+#include <linux/sunrpc/clnt.h>
+#include <linux/sunrpc/svc.h>
+#include <linux/lockd/nlm.h>
+#include <linux/lockd/lockd.h>
+
+#define NLMDBG_FACILITY         NLMDBG_SVCLOCK
+
+#ifdef CONFIG_LOCKD_V4
+#define nlm_deadlock    nlm4_deadlock
+#else
+#define nlm_deadlock    nlm_lck_denied
+#endif
+
+static void     nlmsvc_insert_block(struct nlm_block *block, unsigned long);
+static int      nlmsvc_remove_block(struct nlm_block *block);
+static void     nlmsvc_grant_callback(struct rpc_task *task);
+
+/*
+ * The list of blocked locks to retry
+ */
+static struct nlm_block *       nlm_blocked;
+
+/*
+ * Insert a blocked lock into the global list
+ */
+static void
+nlmsvc_insert_block(struct nlm_block *block, unsigned long when)
+{
+        struct nlm_block **bp, *b;
+
+        dprintk("lockd: nlmsvc_insert_block(%p, %ld)\n", block, when);
+        if (block->b_queued)
+                nlmsvc_remove_block(block);
+        bp = &nlm_blocked;
+        if (when != NLM_NEVER) {
+                if ((when += jiffies) == NLM_NEVER)
+                        when ++;
+                while ((b = *bp) && time_before_eq(b->b_when,when) && b->b_when != NLM_NEVER)
+                        bp = &b->b_next;
+        } else
+                while ((b = *bp) != 0)
+                        bp = &b->b_next;
+
+        block->b_queued = 1;
+        block->b_when = when;
+        block->b_next = b;
+        *bp = block;
+}
+
+/*
+ * Remove a block from the global list
+ */
+static int
+nlmsvc_remove_block(struct nlm_block *block)
+{
+        struct nlm_block **bp, *b;
+
+        if (!block->b_queued)
+                return 1;
+        for (bp = &nlm_blocked; (b = *bp) != 0; bp = &b->b_next) {
+                if (b == block) {
+                        *bp = block->b_next;
+                        block->b_queued = 0;
+                        return 1;
+                }
+        }
+
+        return 0;
+}
+
+/*
+ * Find a block for a given lock and optionally remove it from
+ * the list.
+ */
+static struct nlm_block *
+nlmsvc_lookup_block(struct nlm_file *file, struct nlm_lock *lock, int remove)
+{
+        struct nlm_block        **head, *block;
+        struct file_lock        *fl;
+
+        dprintk("lockd: nlmsvc_lookup_block f=%p pd=%d %Ld-%Ld ty=%d\n",
+                                file, lock->fl.fl_pid,
+                                (long long)lock->fl.fl_start,
+                                (long long)lock->fl.fl_end, lock->fl.fl_type);
+        for (head = &nlm_blocked; (block = *head) != 0; head = &block->b_next) {
+                fl = &block->b_call.a_args.lock.fl;
+                dprintk("lockd: check f=%p pd=%d %Ld-%Ld ty=%d cookie=%s\n",
+                                block->b_file, fl->fl_pid,
+                                (long long)fl->fl_start,
+                                (long long)fl->fl_end, fl->fl_type,
+                                nlmdbg_cookie2a(&block->b_call.a_args.cookie));
+                if (block->b_file == file && nlm_compare_locks(fl, &lock->fl)) {
+                        if (remove) {
+                                *head = block->b_next;
+                                block->b_queued = 0;
+                        }
+                        return block;
+                }
+        }
+
+        return NULL;
+}
+
+static inline int nlm_cookie_match(struct nlm_cookie *a, struct nlm_cookie *b)
+{
+        if(a->len != b->len)
+                return 0;
+        if(memcmp(a->data,b->data,a->len))
+                return 0;
+        return 1;
+}
+
+/*
+ * Find a block with a given NLM cookie.
+ */
+static inline struct nlm_block *
+nlmsvc_find_block(struct nlm_cookie *cookie,  struct sockaddr_in *sin)
+{
+        struct nlm_block *block;
+
+        for (block = nlm_blocked; block; block = block->b_next) {
+                dprintk("cookie: head of blocked queue %p, block %p\n", 
+                        nlm_blocked, block);
+                if (nlm_cookie_match(&block->b_call.a_args.cookie,cookie)
+                                && nlm_cmp_addr(sin, &block->b_host->h_addr))
+                        break;
+        }
+
+        return block;
+}
+
+/*
+ * Create a block and initialize it.
+ *
+ * Note: we explicitly set the cookie of the grant reply to that of
+ * the blocked lock request. The spec explicitly mentions that the client
+ * should _not_ rely on the callback containing the same cookie as the
+ * request, but (as I found out later) that's because some implementations
+ * do just this. Never mind the standards comittees, they support our
+ * logging industries.
+ */
+static inline struct nlm_block *
+nlmsvc_create_block(struct svc_rqst *rqstp, struct nlm_file *file,
+                                struct nlm_lock *lock, struct nlm_cookie *cookie)
+{
+        struct nlm_block        *block;
+        struct nlm_host         *host;
+        struct nlm_rqst         *call;
+
+        /* Create host handle for callback */
+        host = nlmclnt_lookup_host(&rqstp->rq_addr,
+                                rqstp->rq_prot, rqstp->rq_vers);
+        if (host == NULL)
+                return NULL;
+
+        /* Allocate memory for block, and initialize arguments */
+        if (!(block = (struct nlm_block *) kmalloc(sizeof(*block), GFP_KERNEL)))
+                goto failed;
+        memset(block, 0, sizeof(*block));
+        locks_init_lock(&block->b_call.a_args.lock.fl);
+        locks_init_lock(&block->b_call.a_res.lock.fl);
+
+        if (!nlmclnt_setgrantargs(&block->b_call, lock))
+                goto failed_free;
+
+        /* Set notifier function for VFS, and init args */
+        block->b_call.a_args.lock.fl.fl_lmops = &nlmsvc_lock_operations;
+        block->b_call.a_args.cookie = *cookie;  /* see above */
+
+        dprintk("lockd: created block %p...\n", block);
+
+        /* Create and initialize the block */
+        block->b_daemon = rqstp->rq_server;
+        block->b_host   = host;
+        block->b_file   = file;
+
+        /* Add to file's list of blocks */
+        block->b_fnext  = file->f_blocks;
+        file->f_blocks  = block;
+
+        /* Set up RPC arguments for callback */
+        call = &block->b_call;
+        call->a_host    = host;
+        call->a_flags   = RPC_TASK_ASYNC;
+
+        return block;
+
+failed_free:
+        kfree(block);
+failed:
+        nlm_release_host(host);
+        return NULL;
+}
+
+/*
+ * Delete a block. If the lock was cancelled or the grant callback
+ * failed, unlock is set to 1.
+ * It is the caller's responsibility to check whether the file
+ * can be closed hereafter.
+ */
+static void
+nlmsvc_delete_block(struct nlm_block *block, int unlock)
+{
+        struct file_lock        *fl = &block->b_call.a_args.lock.fl;
+        struct nlm_file         *file = block->b_file;
+        struct nlm_block        **bp;
+
+        dprintk("lockd: deleting block %p...\n", block);
+
+        /* Remove block from list */
+        nlmsvc_remove_block(block);
+        if (fl->fl_next)
+                posix_unblock_lock(file->f_file, fl);
+        if (unlock) {
+                fl->fl_type = F_UNLCK;
+                posix_lock_file(file->f_file, fl);
+                block->b_granted = 0;
+        }
+
+        /* If the block is in the middle of a GRANT callback,
+         * don't kill it yet. */
+        if (block->b_incall) {
+                nlmsvc_insert_block(block, NLM_NEVER);
+                block->b_done = 1;
+                return;
+        }
+
+        /* Remove block from file's list of blocks */
+        for (bp = &file->f_blocks; *bp; bp = &(*bp)->b_fnext) {
+                if (*bp == block) {
+                        *bp = block->b_fnext;
+                        break;
+                }
+        }
+
+        if (block->b_host)
+                nlm_release_host(block->b_host);
+        nlmclnt_freegrantargs(&block->b_call);
+        kfree(block);
+}
+
+/*
+ * Loop over all blocks and perform the action specified.
+ * (NLM_ACT_CHECK handled by nlmsvc_inspect_file).
+ */
+int
+nlmsvc_traverse_blocks(struct nlm_host *host, struct nlm_file *file, int action)
+{
+        struct nlm_block        *block, *next;
+
+        down(&file->f_sema);
+        for (block = file->f_blocks; block; block = next) {
+                next = block->b_fnext;
+                if (action == NLM_ACT_MARK)
+                        block->b_host->h_inuse = 1;
+                else if (action == NLM_ACT_UNLOCK) {
+                        if (host == NULL || host == block->b_host)
+                                nlmsvc_delete_block(block, 1);
+                }
+        }
+        up(&file->f_sema);
+        return 0;
+}
+
+/*
+ * Attempt to establish a lock, and if it can't be granted, block it
+ * if required.
+ */
+u32
+nlmsvc_lock(struct svc_rqst *rqstp, struct nlm_file *file,
+                        struct nlm_lock *lock, int wait, struct nlm_cookie *cookie)
+{
+        struct file_lock        *conflock;
+        struct nlm_block        *block;
+        int                     error;
+
+        dprintk("lockd: nlmsvc_lock(%s/%ld, ty=%d, pi=%d, %Ld-%Ld, bl=%d)\n",
+                                file->f_file->f_dentry->d_inode->i_sb->s_id,
+                                file->f_file->f_dentry->d_inode->i_ino,
+                                lock->fl.fl_type, lock->fl.fl_pid,
+                                (long long)lock->fl.fl_start,
+                                (long long)lock->fl.fl_end,
+                                wait);
+
+
+        /* Get existing block (in case client is busy-waiting) */
+        block = nlmsvc_lookup_block(file, lock, 0);
+
+        lock->fl.fl_flags |= FL_LOCKD;
+
+again:
+        /* Lock file against concurrent access */
+        down(&file->f_sema);
+
+        if (!(conflock = posix_test_lock(file->f_file, &lock->fl))) {
+                error = posix_lock_file(file->f_file, &lock->fl);
+
+                if (block)
+                        nlmsvc_delete_block(block, 0);
+                up(&file->f_sema);
+
+                dprintk("lockd: posix_lock_file returned %d\n", -error);
+                switch(-error) {
+                case 0:
+                        return nlm_granted;
+                case EDEADLK:
+                        return nlm_deadlock;
+                case EAGAIN:
+                        return nlm_lck_denied;
+                default:                        /* includes ENOLCK */
+                        return nlm_lck_denied_nolocks;
+                }
+        }
+
+        if (!wait) {
+                up(&file->f_sema);
+                return nlm_lck_denied;
+        }
+
+        if (posix_locks_deadlock(&lock->fl, conflock)) {
+                up(&file->f_sema);
+                return nlm_deadlock;
+        }
+
+        /* If we don't have a block, create and initialize it. Then
+         * retry because we may have slept in kmalloc. */
+        /* We have to release f_sema as nlmsvc_create_block may try to
+         * to claim it while doing host garbage collection */
+        if (block == NULL) {
+                up(&file->f_sema);
+                dprintk("lockd: blocking on this lock (allocating).\n");
+                if (!(block = nlmsvc_create_block(rqstp, file, lock, cookie)))
+                        return nlm_lck_denied_nolocks;
+                goto again;
+        }
+
+        /* Append to list of blocked */
+        nlmsvc_insert_block(block, NLM_NEVER);
+
+        if (list_empty(&block->b_call.a_args.lock.fl.fl_block)) {
+                /* Now add block to block list of the conflicting lock
+                   if we haven't done so. */
+                dprintk("lockd: blocking on this lock.\n");
+                posix_block_lock(conflock, &block->b_call.a_args.lock.fl);
+        }
+
+        up(&file->f_sema);
+        return nlm_lck_blocked;
+}
+
+/*
+ * Test for presence of a conflicting lock.
+ */
+u32
+nlmsvc_testlock(struct nlm_file *file, struct nlm_lock *lock,
+                                       struct nlm_lock *conflock)
+{
+        struct file_lock        *fl;
+
+        dprintk("lockd: nlmsvc_testlock(%s/%ld, ty=%d, %Ld-%Ld)\n",
+                                file->f_file->f_dentry->d_inode->i_sb->s_id,
+                                file->f_file->f_dentry->d_inode->i_ino,
+                                lock->fl.fl_type,
+                                (long long)lock->fl.fl_start,
+                                (long long)lock->fl.fl_end);
+
+        if ((fl = posix_test_lock(file->f_file, &lock->fl)) != NULL) {
+                dprintk("lockd: conflicting lock(ty=%d, %Ld-%Ld)\n",
+                                fl->fl_type, (long long)fl->fl_start,
+                                (long long)fl->fl_end);
+                conflock->caller = "somehost";  /* FIXME */
+                conflock->oh.len = 0;           /* don't return OH info */
+                conflock->fl = *fl;
+                return nlm_lck_denied;
+        }
+
+        return nlm_granted;
+}
+
+/*
+ * Remove a lock.
+ * This implies a CANCEL call: We send a GRANT_MSG, the client replies
+ * with a GRANT_RES call which gets lost, and calls UNLOCK immediately
+ * afterwards. In this case the block will still be there, and hence
+ * must be removed.
+ */
+u32
+nlmsvc_unlock(struct nlm_file *file, struct nlm_lock *lock)
+{
+        int     error;
+
+        dprintk("lockd: nlmsvc_unlock(%s/%ld, pi=%d, %Ld-%Ld)\n",
+                                file->f_file->f_dentry->d_inode->i_sb->s_id,
+                                file->f_file->f_dentry->d_inode->i_ino,
+                                lock->fl.fl_pid,
+                                (long long)lock->fl.fl_start,
+                                (long long)lock->fl.fl_end);
+
+        /* First, cancel any lock that might be there */
+        nlmsvc_cancel_blocked(file, lock);
+
+        lock->fl.fl_type = F_UNLCK;
+        error = posix_lock_file(file->f_file, &lock->fl);
+
+        return (error < 0)? nlm_lck_denied_nolocks : nlm_granted;
+}
+
+/*
+ * Cancel a previously blocked request.
+ *
+ * A cancel request always overrides any grant that may currently
+ * be in progress.
+ * The calling procedure must check whether the file can be closed.
+ */
+u32
+nlmsvc_cancel_blocked(struct nlm_file *file, struct nlm_lock *lock)
+{
+        struct nlm_block        *block;
+
+        dprintk("lockd: nlmsvc_cancel(%s/%ld, pi=%d, %Ld-%Ld)\n",
+                                file->f_file->f_dentry->d_inode->i_sb->s_id,
+                                file->f_file->f_dentry->d_inode->i_ino,
+                                lock->fl.fl_pid,
+                                (long long)lock->fl.fl_start,
+                                (long long)lock->fl.fl_end);
+
+        down(&file->f_sema);
+        if ((block = nlmsvc_lookup_block(file, lock, 1)) != NULL)
+                nlmsvc_delete_block(block, 1);
+        up(&file->f_sema);
+        return nlm_granted;
+}
+
+/*
+ * Unblock a blocked lock request. This is a callback invoked from the
+ * VFS layer when a lock on which we blocked is removed.
+ *
+ * This function doesn't grant the blocked lock instantly, but rather moves
+ * the block to the head of nlm_blocked where it can be picked up by lockd.
+ */
+static void
+nlmsvc_notify_blocked(struct file_lock *fl)
+{
+        struct nlm_block        **bp, *block;
+
+        dprintk("lockd: VFS unblock notification for block %p\n", fl);
+        for (bp = &nlm_blocked; (block = *bp) != 0; bp = &block->b_next) {
+                if (nlm_compare_locks(&block->b_call.a_args.lock.fl, fl)) {
+                        nlmsvc_insert_block(block, 0);
+                        svc_wake_up(block->b_daemon);
+                        return;
+                }
+        }
+
+        printk(KERN_WARNING "lockd: notification for unknown block!\n");
+}
+
+static int nlmsvc_same_owner(struct file_lock *fl1, struct file_lock *fl2)
+{
+        return fl1->fl_owner == fl2->fl_owner && fl1->fl_pid == fl2->fl_pid;
+}
+
+struct lock_manager_operations nlmsvc_lock_operations = {
+        .fl_compare_owner = nlmsvc_same_owner,
+        .fl_notify = nlmsvc_notify_blocked,
+};
+
+/*
+ * Try to claim a lock that was previously blocked.
+ *
+ * Note that we use both the RPC_GRANTED_MSG call _and_ an async
+ * RPC thread when notifying the client. This seems like overkill...
+ * Here's why:
+ *  -   we don't want to use a synchronous RPC thread, otherwise
+ *      we might find ourselves hanging on a dead portmapper.
+ *  -   Some lockd implementations (e.g. HP) don't react to
+ *      RPC_GRANTED calls; they seem to insist on RPC_GRANTED_MSG calls.
+ */
+static void
+nlmsvc_grant_blocked(struct nlm_block *block)
+{
+        struct nlm_file         *file = block->b_file;
+        struct nlm_lock         *lock = &block->b_call.a_args.lock;
+        struct file_lock        *conflock;
+        int                     error;
+
+        dprintk("lockd: grant blocked lock %p\n", block);
+
+        /* First thing is lock the file */
+        down(&file->f_sema);
+
+        /* Unlink block request from list */
+        nlmsvc_remove_block(block);
+
+        /* If b_granted is true this means we've been here before.
+         * Just retry the grant callback, possibly refreshing the RPC
+         * binding */
+        if (block->b_granted) {
+                nlm_rebind_host(block->b_host);
+                goto callback;
+        }
+
+        /* Try the lock operation again */
+        if ((conflock = posix_test_lock(file->f_file, &lock->fl)) != NULL) {
+                /* Bummer, we blocked again */
+                dprintk("lockd: lock still blocked\n");
+                nlmsvc_insert_block(block, NLM_NEVER);
+                posix_block_lock(conflock, &lock->fl);
+                up(&file->f_sema);
+                return;
+        }
+
+        /* Alright, no conflicting lock. Now lock it for real. If the
+         * following yields an error, this is most probably due to low
+         * memory. Retry the lock in a few seconds.
+         */
+        if ((error = posix_lock_file(file->f_file, &lock->fl)) < 0) {
+                printk(KERN_WARNING "lockd: unexpected error %d in %s!\n",
+                                -error, __FUNCTION__);
+                nlmsvc_insert_block(block, 10 * HZ);
+                up(&file->f_sema);
+                return;
+        }
+
+callback:
+        /* Lock was granted by VFS. */
+        dprintk("lockd: GRANTing blocked lock.\n");
+        block->b_granted = 1;
+        block->b_incall  = 1;
+
+        /* Schedule next grant callback in 30 seconds */
+        nlmsvc_insert_block(block, 30 * HZ);
+
+        /* Call the client */
+        nlm_get_host(block->b_call.a_host);
+        if (nlmsvc_async_call(&block->b_call, NLMPROC_GRANTED_MSG,
+                                                nlmsvc_grant_callback) < 0)
+                nlm_release_host(block->b_call.a_host);
+        up(&file->f_sema);
+}
+
+/*
+ * This is the callback from the RPC layer when the NLM_GRANTED_MSG
+ * RPC call has succeeded or timed out.
+ * Like all RPC callbacks, it is invoked by the rpciod process, so it
+ * better not sleep. Therefore, we put the blocked lock on the nlm_blocked
+ * chain once more in order to have it removed by lockd itself (which can
+ * then sleep on the file semaphore without disrupting e.g. the nfs client).
+ */
+static void
+nlmsvc_grant_callback(struct rpc_task *task)
+{
+        struct nlm_rqst         *call = (struct nlm_rqst *) task->tk_calldata;
+        struct nlm_block        *block;
+        unsigned long           timeout;
+        struct sockaddr_in      *peer_addr = RPC_PEERADDR(task->tk_client);
+
+        dprintk("lockd: GRANT_MSG RPC callback\n");
+        dprintk("callback: looking for cookie %s, host (%u.%u.%u.%u)\n",
+                nlmdbg_cookie2a(&call->a_args.cookie),
+                NIPQUAD(peer_addr->sin_addr.s_addr));
+        if (!(block = nlmsvc_find_block(&call->a_args.cookie, peer_addr))) {
+                dprintk("lockd: no block for cookie %s, host (%u.%u.%u.%u)\n",
+                        nlmdbg_cookie2a(&call->a_args.cookie),
+                        NIPQUAD(peer_addr->sin_addr.s_addr));
+                return;
+        }
+
+        /* Technically, we should down the file semaphore here. Since we
+         * move the block towards the head of the queue only, no harm
+         * can be done, though. */
+        if (task->tk_status < 0) {
+                /* RPC error: Re-insert for retransmission */
+                timeout = 10 * HZ;
+        } else if (block->b_done) {
+                /* Block already removed, kill it for real */
+                timeout = 0;
+        } else {
+                /* Call was successful, now wait for client callback */
+                timeout = 60 * HZ;
+        }
+        nlmsvc_insert_block(block, timeout);
+        svc_wake_up(block->b_daemon);
+        block->b_incall = 0;
+
+        nlm_release_host(call->a_host);
+}
+
+/*
+ * We received a GRANT_RES callback. Try to find the corresponding
+ * block.
+ */
+void
+nlmsvc_grant_reply(struct svc_rqst *rqstp, struct nlm_cookie *cookie, u32 status)
+{
+        struct nlm_block        *block;
+        struct nlm_file         *file;
+
+        dprintk("grant_reply: looking for cookie %x, host (%08x), s=%d \n", 
+                *(unsigned int *)(cookie->data), 
+                ntohl(rqstp->rq_addr.sin_addr.s_addr), status);
+        if (!(block = nlmsvc_find_block(cookie, &rqstp->rq_addr)))
+                return;
+        file = block->b_file;
+
+        file->f_count++;
+        down(&file->f_sema);
+        if ((block = nlmsvc_find_block(cookie,&rqstp->rq_addr)) != NULL) {
+                if (status == NLM_LCK_DENIED_GRACE_PERIOD) {
+                        /* Try again in a couple of seconds */
+                        nlmsvc_insert_block(block, 10 * HZ);
+                        block = NULL;
+                } else {
+                        /* Lock is now held by client, or has been rejected.
+                         * In both cases, the block should be removed. */
+                        up(&file->f_sema);
+                        if (status == NLM_LCK_GRANTED)
+                                nlmsvc_delete_block(block, 0);
+                        else
+                                nlmsvc_delete_block(block, 1);
+                }
+        }
+        if (!block)
+                up(&file->f_sema);
+        nlm_release_file(file);
+}
+
+/*
+ * Retry all blocked locks that have been notified. This is where lockd
+ * picks up locks that can be granted, or grant notifications that must
+ * be retransmitted.
+ */
+unsigned long
+nlmsvc_retry_blocked(void)
+{
+        struct nlm_block        *block;
+
+        dprintk("nlmsvc_retry_blocked(%p, when=%ld)\n",
+                        nlm_blocked,
+                        nlm_blocked? nlm_blocked->b_when : 0);
+        while ((block = nlm_blocked) != 0) {
+                if (block->b_when == NLM_NEVER)
+                        break;
+                if (time_after(block->b_when,jiffies))
+                        break;
+                dprintk("nlmsvc_retry_blocked(%p, when=%ld, done=%d)\n",
+                        block, block->b_when, block->b_done);
+                if (block->b_done)
+                        nlmsvc_delete_block(block, 0);
+                else
+                        nlmsvc_grant_blocked(block);
+        }
+
+        if ((block = nlm_blocked) && block->b_when != NLM_NEVER)
+                return (block->b_when - jiffies);
+
+        return MAX_SCHEDULE_TIMEOUT;
+}