Commit 1a8322b2 authored by Marc Eshel's avatar Marc Eshel Committed by J. Bruce Fields
Browse files

lockd: add code to handle deferred lock requests 



Rewrite nlmsvc_lock() to use the asynchronous interface.

As with testlock, we answer nlm requests in nlmsvc_lock by first looking up
the block and then using the results we find in the block if B_QUEUED is
set, and calling vfs_lock_file() otherwise.

If this a new lock request and we get -EINPROGRESS return on a non-blocking
request then we defer the request.

Also modify nlmsvc_unlock() to call the filesystem method if appropriate.

Signed-off-by: default avatarMarc Eshel <eshel@almaden.ibm.com>
Signed-off-by: default avatarJ. Bruce Fields <bfields@citi.umich.edu>
parent f8120480

fs/lockd/svc4proc.c

+2 −0
Original line number Diff line number Diff line
@@ -145,6 +145,8 @@ nlm4svc_proc_lock(struct svc_rqst *rqstp, struct nlm_args *argp, 
	/* Now try to lock the file */

	resp->status = nlmsvc_lock(rqstp, file, &argp->lock,

					argp->block, &argp->cookie);

	if (resp->status == nlm_drop_reply)

		return rpc_drop_reply;



	dprintk("lockd: LOCK          status %d\n", ntohl(resp->status));

	nlm_release_host(host);

fs/lockd/svclock.c

+35 −6
Original line number Diff line number Diff line
@@ -393,17 +393,43 @@ nlmsvc_lock(struct svc_rqst *rqstp, struct nlm_file *file, 
	} else

		lock->fl.fl_flags &= ~FL_SLEEP;



	error = posix_lock_file(file->f_file, &lock->fl, NULL);

	lock->fl.fl_flags &= ~FL_SLEEP;

	if (block->b_flags & B_QUEUED) {

		dprintk("lockd: nlmsvc_lock deferred block %p flags %d\n",

							block, block->b_flags);

		if (block->b_granted) {

			nlmsvc_unlink_block(block);

			ret = nlm_granted;

			goto out;

		}

		if (block->b_flags & B_TIMED_OUT) {

			nlmsvc_unlink_block(block);

			ret = nlm_lck_denied;

			goto out;

		}

		ret = nlm_drop_reply;

		goto out;

	}



	dprintk("lockd: posix_lock_file returned %d\n", error);

	if (!wait)

		lock->fl.fl_flags &= ~FL_SLEEP;

	error = vfs_lock_file(file->f_file, F_SETLK, &lock->fl, NULL);

	lock->fl.fl_flags &= ~FL_SLEEP;



	dprintk("lockd: vfs_lock_file returned %d\n", error);

	switch(error) {

		case 0:

			ret = nlm_granted;

			goto out;

		case -EAGAIN:

			ret = nlm_lck_denied;

			break;

		case -EINPROGRESS:

			if (wait)

				break;

			/* Filesystem lock operation is in progress

			   Add it to the queue waiting for callback */

			ret = nlmsvc_defer_lock_rqst(rqstp, block);

			goto out;

		case -EDEADLK:

			ret = nlm_deadlock;

			goto out;
@@ -535,7 +561,7 @@ nlmsvc_unlock(struct nlm_file *file, struct nlm_lock *lock) 
	nlmsvc_cancel_blocked(file, lock);



	lock->fl.fl_type = F_UNLCK;

	error = posix_lock_file(file->f_file, &lock->fl, NULL);

	error = vfs_lock_file(file->f_file, F_SETLK, &lock->fl, NULL);



	return (error < 0)? nlm_lck_denied_nolocks : nlm_granted;

}
@@ -564,6 +590,8 @@ nlmsvc_cancel_blocked(struct nlm_file *file, struct nlm_lock *lock) 
	block = nlmsvc_lookup_block(file, lock);

	mutex_unlock(&file->f_mutex);

	if (block != NULL) {

		vfs_cancel_lock(block->b_file->f_file,

				&block->b_call->a_args.lock.fl);

		status = nlmsvc_unlink_block(block);

		nlmsvc_release_block(block);

	}
@@ -697,14 +725,15 @@ nlmsvc_grant_blocked(struct nlm_block *block) 


	/* Try the lock operation again */

	lock->fl.fl_flags |= FL_SLEEP;

	error = posix_lock_file(file->f_file, &lock->fl, NULL);

	error = vfs_lock_file(file->f_file, F_SETLK, &lock->fl, NULL);

	lock->fl.fl_flags &= ~FL_SLEEP;



	switch (error) {

	case 0:

		break;

	case -EAGAIN:

		dprintk("lockd: lock still blocked\n");

	case -EINPROGRESS:

		dprintk("lockd: lock still blocked error %d\n", error);

		nlmsvc_insert_block(block, NLM_NEVER);

		nlmsvc_release_block(block);

		return;

fs/lockd/svcproc.c

+2 −0
Original line number Diff line number Diff line
@@ -175,6 +175,8 @@ nlmsvc_proc_lock(struct svc_rqst *rqstp, struct nlm_args *argp, 
	/* Now try to lock the file */

	resp->status = cast_status(nlmsvc_lock(rqstp, file, &argp->lock,

					       argp->block, &argp->cookie));

	if (resp->status == nlm_drop_reply)

		return rpc_drop_reply;



	dprintk("lockd: LOCK          status %d\n", ntohl(resp->status));

	nlm_release_host(host);

fs/lockd/svcsubs.c

+1 −1
Original line number Diff line number Diff line
@@ -182,7 +182,7 @@ again: 
			lock.fl_type  = F_UNLCK;

			lock.fl_start = 0;

			lock.fl_end   = OFFSET_MAX;

			if (posix_lock_file(file->f_file, &lock, NULL) < 0) {

			if (vfs_lock_file(file->f_file, F_SETLK, &lock, NULL) < 0) {

				printk("lockd: unlock failure in %s:%d\n",

						__FILE__, __LINE__);

				return 1;

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