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lockd: Add refcounting to struct nlm_block
Otherwise, the block may disappear from underneath us when in nlmsvc_retry_blocked. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
This commit is contained in:
Trond Myklebust
parent
09c7938c56
commit
6849c0cab6
@ -39,6 +39,7 @@
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#define nlm_deadlock nlm_lck_denied
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#endif
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static void nlmsvc_release_block(struct nlm_block *block);
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static void nlmsvc_insert_block(struct nlm_block *block, unsigned long);
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static int nlmsvc_remove_block(struct nlm_block *block);
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@ -58,6 +59,7 @@ nlmsvc_insert_block(struct nlm_block *block, unsigned long when)
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struct nlm_block **bp, *b;
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dprintk("lockd: nlmsvc_insert_block(%p, %ld)\n", block, when);
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kref_get(&block->b_count);
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if (block->b_queued)
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nlmsvc_remove_block(block);
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bp = &nlm_blocked;
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@ -90,6 +92,7 @@ nlmsvc_remove_block(struct nlm_block *block)
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if (b == block) {
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*bp = block->b_next;
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block->b_queued = 0;
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nlmsvc_release_block(block);
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return 1;
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}
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}
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@ -123,6 +126,7 @@ nlmsvc_lookup_block(struct nlm_file *file, struct nlm_lock *lock, int remove)
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*head = block->b_next;
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block->b_queued = 0;
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}
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kref_get(&block->b_count);
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return block;
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}
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}
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@ -155,6 +159,8 @@ nlmsvc_find_block(struct nlm_cookie *cookie, struct sockaddr_in *sin)
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break;
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}
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if (block != NULL)
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kref_get(&block->b_count);
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return block;
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}
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@ -188,6 +194,7 @@ nlmsvc_create_block(struct svc_rqst *rqstp, struct nlm_file *file,
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memset(block, 0, sizeof(*block));
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locks_init_lock(&block->b_call.a_args.lock.fl);
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locks_init_lock(&block->b_call.a_res.lock.fl);
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kref_init(&block->b_count);
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if (!nlmclnt_setgrantargs(&block->b_call, lock))
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goto failed_free;
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@ -228,27 +235,24 @@ failed:
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* It is the caller's responsibility to check whether the file
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* can be closed hereafter.
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*/
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static int
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nlmsvc_delete_block(struct nlm_block *block)
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static int nlmsvc_unlink_block(struct nlm_block *block)
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{
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struct file_lock *fl = &block->b_call.a_args.lock.fl;
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struct nlm_file *file = block->b_file;
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struct nlm_block **bp;
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int status;
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dprintk("lockd: deleting block %p...\n", block);
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dprintk("lockd: unlinking block %p...\n", block);
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/* Remove block from list */
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status = posix_unblock_lock(block->b_file->f_file, &block->b_call.a_args.lock.fl);
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nlmsvc_remove_block(block);
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status = posix_unblock_lock(file->f_file, fl);
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return status;
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}
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/* If the block is in the middle of a GRANT callback,
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* don't kill it yet. */
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if (block->b_incall) {
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nlmsvc_insert_block(block, NLM_NEVER);
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block->b_done = 1;
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return status;
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}
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static void nlmsvc_free_block(struct kref *kref)
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{
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struct nlm_block *block = container_of(kref, struct nlm_block, b_count);
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struct nlm_file *file = block->b_file;
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struct nlm_block **bp;
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dprintk("lockd: freeing block %p...\n", block);
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/* Remove block from file's list of blocks */
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for (bp = &file->f_blocks; *bp; bp = &(*bp)->b_fnext) {
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@ -262,7 +266,12 @@ nlmsvc_delete_block(struct nlm_block *block)
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nlm_release_host(block->b_host);
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nlmclnt_freegrantargs(&block->b_call);
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kfree(block);
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return status;
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}
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static void nlmsvc_release_block(struct nlm_block *block)
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{
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if (block != NULL)
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kref_put(&block->b_count, nlmsvc_free_block);
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}
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/*
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@ -282,7 +291,7 @@ nlmsvc_traverse_blocks(struct nlm_host *host, struct nlm_file *file, int action)
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block->b_host->h_inuse = 1;
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else if (action == NLM_ACT_UNLOCK) {
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if (host == NULL || host == block->b_host)
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nlmsvc_delete_block(block);
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nlmsvc_unlink_block(block);
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}
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}
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up(&file->f_sema);
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@ -318,9 +327,9 @@ again:
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block = nlmsvc_lookup_block(file, lock, 0);
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if (block == NULL) {
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if (newblock != NULL)
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lock = &newblock->b_call.a_args.lock.fl;
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lock = &newblock->b_call.a_args.lock;
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} else
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lock = &block->b_call.a_args.lock.fl;
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lock = &block->b_call.a_args.lock;
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error = posix_lock_file(file->f_file, &lock->fl);
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lock->fl.fl_flags &= ~FL_SLEEP;
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@ -363,12 +372,10 @@ again:
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/* Append to list of blocked */
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nlmsvc_insert_block(newblock, NLM_NEVER);
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newblock = NULL;
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out:
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up(&file->f_sema);
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if (newblock != NULL)
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nlmsvc_delete_block(newblock);
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nlmsvc_release_block(newblock);
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nlmsvc_release_block(block);
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dprintk("lockd: nlmsvc_lock returned %u\n", ret);
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return ret;
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}
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@ -450,8 +457,10 @@ nlmsvc_cancel_blocked(struct nlm_file *file, struct nlm_lock *lock)
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(long long)lock->fl.fl_end);
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down(&file->f_sema);
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if ((block = nlmsvc_lookup_block(file, lock, 1)) != NULL)
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status = nlmsvc_delete_block(block);
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if ((block = nlmsvc_lookup_block(file, lock, 1)) != NULL) {
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status = nlmsvc_unlink_block(block);
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nlmsvc_release_block(block);
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}
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up(&file->f_sema);
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return status ? nlm_lck_denied : nlm_granted;
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}
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@ -514,7 +523,7 @@ nlmsvc_grant_blocked(struct nlm_block *block)
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down(&file->f_sema);
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/* Unlink block request from list */
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nlmsvc_remove_block(block);
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nlmsvc_unlink_block(block);
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/* If b_granted is true this means we've been here before.
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* Just retry the grant callback, possibly refreshing the RPC
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@ -525,7 +534,6 @@ nlmsvc_grant_blocked(struct nlm_block *block)
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}
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/* Try the lock operation again */
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posix_unblock_lock(file->f_file, &lock->fl);
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lock->fl.fl_flags |= FL_SLEEP;
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error = posix_lock_file(file->f_file, &lock->fl);
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lock->fl.fl_flags &= ~FL_SLEEP;
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@ -548,16 +556,15 @@ callback:
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/* Lock was granted by VFS. */
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dprintk("lockd: GRANTing blocked lock.\n");
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block->b_granted = 1;
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block->b_incall = 1;
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/* Schedule next grant callback in 30 seconds */
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nlmsvc_insert_block(block, 30 * HZ);
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/* Call the client */
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nlm_get_host(block->b_call.a_host);
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kref_get(&block->b_count);
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if (nlmsvc_async_call(&block->b_call, NLMPROC_GRANTED_MSG,
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&nlmsvc_grant_ops) < 0)
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nlm_release_host(block->b_call.a_host);
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nlmsvc_release_block(block);
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out_unlock:
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up(&file->f_sema);
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}
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@ -573,20 +580,10 @@ out_unlock:
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static void nlmsvc_grant_callback(struct rpc_task *task, void *data)
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{
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struct nlm_rqst *call = data;
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struct nlm_block *block;
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struct nlm_block *block = container_of(call, struct nlm_block, b_call);
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unsigned long timeout;
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struct sockaddr_in *peer_addr = RPC_PEERADDR(task->tk_client);
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dprintk("lockd: GRANT_MSG RPC callback\n");
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dprintk("callback: looking for cookie %s, host (%u.%u.%u.%u)\n",
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nlmdbg_cookie2a(&call->a_args.cookie),
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NIPQUAD(peer_addr->sin_addr.s_addr));
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if (!(block = nlmsvc_find_block(&call->a_args.cookie, peer_addr))) {
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dprintk("lockd: no block for cookie %s, host (%u.%u.%u.%u)\n",
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nlmdbg_cookie2a(&call->a_args.cookie),
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NIPQUAD(peer_addr->sin_addr.s_addr));
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return;
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}
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/* Technically, we should down the file semaphore here. Since we
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* move the block towards the head of the queue only, no harm
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@ -603,9 +600,7 @@ static void nlmsvc_grant_callback(struct rpc_task *task, void *data)
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}
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nlmsvc_insert_block(block, timeout);
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svc_wake_up(block->b_daemon);
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block->b_incall = 0;
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nlm_release_host(call->a_host);
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nlmsvc_release_block(block);
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}
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static const struct rpc_call_ops nlmsvc_grant_ops = {
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@ -631,20 +626,19 @@ nlmsvc_grant_reply(struct svc_rqst *rqstp, struct nlm_cookie *cookie, u32 status
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file->f_count++;
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down(&file->f_sema);
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block = nlmsvc_find_block(cookie, &rqstp->rq_addr);
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if (block) {
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if (status == NLM_LCK_DENIED_GRACE_PERIOD) {
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/* Try again in a couple of seconds */
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nlmsvc_insert_block(block, 10 * HZ);
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up(&file->f_sema);
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} else {
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/* Lock is now held by client, or has been rejected.
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* In both cases, the block should be removed. */
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nlmsvc_delete_block(block);
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up(&file->f_sema);
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nlmsvc_unlink_block(block);
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}
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}
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up(&file->f_sema);
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nlm_release_file(file);
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nlmsvc_release_block(block);
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}
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/*
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@ -667,10 +661,12 @@ nlmsvc_retry_blocked(void)
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break;
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dprintk("nlmsvc_retry_blocked(%p, when=%ld, done=%d)\n",
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block, block->b_when, block->b_done);
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kref_get(&block->b_count);
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if (block->b_done)
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nlmsvc_delete_block(block);
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nlmsvc_unlink_block(block);
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else
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nlmsvc_grant_blocked(block);
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nlmsvc_release_block(block);
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}
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if ((block = nlm_blocked) && block->b_when != NLM_NEVER)
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@ -14,6 +14,7 @@
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#include <linux/config.h>
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#include <linux/in.h>
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#include <linux/fs.h>
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#include <linux/kref.h>
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#include <linux/utsname.h>
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#include <linux/nfsd/nfsfh.h>
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#include <linux/lockd/bind.h>
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@ -110,6 +111,7 @@ struct nlm_file {
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*/
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#define NLM_NEVER (~(unsigned long) 0)
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struct nlm_block {
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struct kref b_count; /* Reference count */
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struct nlm_block * b_next; /* linked list (all blocks) */
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struct nlm_block * b_fnext; /* linked list (per file) */
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struct nlm_rqst b_call; /* RPC args & callback info */
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@ -119,7 +121,6 @@ struct nlm_block {
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unsigned int b_id; /* block id */
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unsigned char b_queued; /* re-queued */
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unsigned char b_granted; /* VFS granted lock */
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unsigned char b_incall; /* doing callback */
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unsigned char b_done; /* callback complete */
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struct nlm_file * b_file; /* file in question */
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};
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