Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 708 insertions, 0 deletions

diff --git a/fs/afs/flock.c b/fs/afs/flock.c
new file mode 100644
index 000000000..fbf4986b1
--- /dev/null
+++ b/fs/afs/flock.c
@@ -0,0 +1,708 @@
+/* AFS file locking support
+ *
+ * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include "internal.h"
+
+#define AFS_LOCK_GRANTED	0
+#define AFS_LOCK_PENDING	1
+#define AFS_LOCK_YOUR_TRY	2
+
+struct workqueue_struct *afs_lock_manager;
+
+static void afs_next_locker(struct afs_vnode *vnode, int error);
+static void afs_fl_copy_lock(struct file_lock *new, struct file_lock *fl);
+static void afs_fl_release_private(struct file_lock *fl);
+
+static const struct file_lock_operations afs_lock_ops = {
+	.fl_copy_lock		= afs_fl_copy_lock,
+	.fl_release_private	= afs_fl_release_private,
+};
+
+static inline void afs_set_lock_state(struct afs_vnode *vnode, enum afs_lock_state state)
+{
+	_debug("STATE %u -> %u", vnode->lock_state, state);
+	vnode->lock_state = state;
+}
+
+/*
+ * if the callback is broken on this vnode, then the lock may now be available
+ */
+void afs_lock_may_be_available(struct afs_vnode *vnode)
+{
+	_enter("{%x:%u}", vnode->fid.vid, vnode->fid.vnode);
+
+	spin_lock(&vnode->lock);
+	if (vnode->lock_state == AFS_VNODE_LOCK_WAITING_FOR_CB)
+		afs_next_locker(vnode, 0);
+	spin_unlock(&vnode->lock);
+}
+
+/*
+ * the lock will time out in 5 minutes unless we extend it, so schedule
+ * extension in a bit less than that time
+ */
+static void __maybe_unused afs_schedule_lock_extension(struct afs_vnode *vnode)
+{
+	queue_delayed_work(afs_lock_manager, &vnode->lock_work,
+			   AFS_LOCKWAIT * HZ / 2);
+}
+
+/*
+ * grant one or more locks (readlocks are allowed to jump the queue if the
+ * first lock in the queue is itself a readlock)
+ * - the caller must hold the vnode lock
+ */
+static void afs_grant_locks(struct afs_vnode *vnode)
+{
+	struct file_lock *p, *_p;
+	bool exclusive = (vnode->lock_type == AFS_LOCK_WRITE);
+
+	list_for_each_entry_safe(p, _p, &vnode->pending_locks, fl_u.afs.link) {
+		if (!exclusive && p->fl_type == F_WRLCK)
+			continue;
+
+		list_move_tail(&p->fl_u.afs.link, &vnode->granted_locks);
+		p->fl_u.afs.state = AFS_LOCK_GRANTED;
+		wake_up(&p->fl_wait);
+	}
+}
+
+/*
+ * If an error is specified, reject every pending lock that matches the
+ * authentication and type of the lock we failed to get.  If there are any
+ * remaining lockers, try to wake up one of them to have a go.
+ */
+static void afs_next_locker(struct afs_vnode *vnode, int error)
+{
+	struct file_lock *p, *_p, *next = NULL;
+	struct key *key = vnode->lock_key;
+	unsigned int fl_type = F_RDLCK;
+
+	_enter("");
+
+	if (vnode->lock_type == AFS_LOCK_WRITE)
+		fl_type = F_WRLCK;
+
+	list_for_each_entry_safe(p, _p, &vnode->pending_locks, fl_u.afs.link) {
+		if (error &&
+		    p->fl_type == fl_type &&
+		    afs_file_key(p->fl_file) == key) {
+			list_del_init(&p->fl_u.afs.link);
+			p->fl_u.afs.state = error;
+			wake_up(&p->fl_wait);
+		}
+
+		/* Select the next locker to hand off to. */
+		if (next &&
+		    (next->fl_type == F_WRLCK || p->fl_type == F_RDLCK))
+			continue;
+		next = p;
+	}
+
+	vnode->lock_key = NULL;
+	key_put(key);
+
+	if (next) {
+		afs_set_lock_state(vnode, AFS_VNODE_LOCK_SETTING);
+		next->fl_u.afs.state = AFS_LOCK_YOUR_TRY;
+		wake_up(&next->fl_wait);
+	} else {
+		afs_set_lock_state(vnode, AFS_VNODE_LOCK_NONE);
+	}
+
+	_leave("");
+}
+
+/*
+ * Get a lock on a file
+ */
+static int afs_set_lock(struct afs_vnode *vnode, struct key *key,
+			afs_lock_type_t type)
+{
+	struct afs_fs_cursor fc;
+	int ret;
+
+	_enter("%s{%x:%u.%u},%x,%u",
+	       vnode->volume->name,
+	       vnode->fid.vid,
+	       vnode->fid.vnode,
+	       vnode->fid.unique,
+	       key_serial(key), type);
+
+	ret = -ERESTARTSYS;
+	if (afs_begin_vnode_operation(&fc, vnode, key)) {
+		while (afs_select_fileserver(&fc)) {
+			fc.cb_break = afs_calc_vnode_cb_break(vnode);
+			afs_fs_set_lock(&fc, type);
+		}
+
+		afs_check_for_remote_deletion(&fc, fc.vnode);
+		afs_vnode_commit_status(&fc, vnode, fc.cb_break);
+		ret = afs_end_vnode_operation(&fc);
+	}
+
+	_leave(" = %d", ret);
+	return ret;
+}
+
+/*
+ * Extend a lock on a file
+ */
+static int afs_extend_lock(struct afs_vnode *vnode, struct key *key)
+{
+	struct afs_fs_cursor fc;
+	int ret;
+
+	_enter("%s{%x:%u.%u},%x",
+	       vnode->volume->name,
+	       vnode->fid.vid,
+	       vnode->fid.vnode,
+	       vnode->fid.unique,
+	       key_serial(key));
+
+	ret = -ERESTARTSYS;
+	if (afs_begin_vnode_operation(&fc, vnode, key)) {
+		while (afs_select_current_fileserver(&fc)) {
+			fc.cb_break = afs_calc_vnode_cb_break(vnode);
+			afs_fs_extend_lock(&fc);
+		}
+
+		afs_check_for_remote_deletion(&fc, fc.vnode);
+		afs_vnode_commit_status(&fc, vnode, fc.cb_break);
+		ret = afs_end_vnode_operation(&fc);
+	}
+
+	_leave(" = %d", ret);
+	return ret;
+}
+
+/*
+ * Release a lock on a file
+ */
+static int afs_release_lock(struct afs_vnode *vnode, struct key *key)
+{
+	struct afs_fs_cursor fc;
+	int ret;
+
+	_enter("%s{%x:%u.%u},%x",
+	       vnode->volume->name,
+	       vnode->fid.vid,
+	       vnode->fid.vnode,
+	       vnode->fid.unique,
+	       key_serial(key));
+
+	ret = -ERESTARTSYS;
+	if (afs_begin_vnode_operation(&fc, vnode, key)) {
+		while (afs_select_current_fileserver(&fc)) {
+			fc.cb_break = afs_calc_vnode_cb_break(vnode);
+			afs_fs_release_lock(&fc);
+		}
+
+		afs_check_for_remote_deletion(&fc, fc.vnode);
+		afs_vnode_commit_status(&fc, vnode, fc.cb_break);
+		ret = afs_end_vnode_operation(&fc);
+	}
+
+	_leave(" = %d", ret);
+	return ret;
+}
+
+/*
+ * do work for a lock, including:
+ * - probing for a lock we're waiting on but didn't get immediately
+ * - extending a lock that's close to timing out
+ */
+void afs_lock_work(struct work_struct *work)
+{
+	struct afs_vnode *vnode =
+		container_of(work, struct afs_vnode, lock_work.work);
+	struct key *key;
+	int ret;
+
+	_enter("{%x:%u}", vnode->fid.vid, vnode->fid.vnode);
+
+	spin_lock(&vnode->lock);
+
+again:
+	_debug("wstate %u for %p", vnode->lock_state, vnode);
+	switch (vnode->lock_state) {
+	case AFS_VNODE_LOCK_NEED_UNLOCK:
+		_debug("unlock");
+		afs_set_lock_state(vnode, AFS_VNODE_LOCK_UNLOCKING);
+		spin_unlock(&vnode->lock);
+
+		/* attempt to release the server lock; if it fails, we just
+		 * wait 5 minutes and it'll expire anyway */
+		ret = afs_release_lock(vnode, vnode->lock_key);
+		if (ret < 0)
+			printk(KERN_WARNING "AFS:"
+			       " Failed to release lock on {%x:%x} error %d\n",
+			       vnode->fid.vid, vnode->fid.vnode, ret);
+
+		spin_lock(&vnode->lock);
+		afs_next_locker(vnode, 0);
+		spin_unlock(&vnode->lock);
+		return;
+
+	/* If we've already got a lock, then it must be time to extend that
+	 * lock as AFS locks time out after 5 minutes.
+	 */
+	case AFS_VNODE_LOCK_GRANTED:
+		_debug("extend");
+
+		ASSERT(!list_empty(&vnode->granted_locks));
+
+		key = key_get(vnode->lock_key);
+		afs_set_lock_state(vnode, AFS_VNODE_LOCK_EXTENDING);
+		spin_unlock(&vnode->lock);
+
+		ret = afs_extend_lock(vnode, key); /* RPC */
+		key_put(key);
+
+		if (ret < 0)
+			pr_warning("AFS: Failed to extend lock on {%x:%x} error %d\n",
+				   vnode->fid.vid, vnode->fid.vnode, ret);
+
+		spin_lock(&vnode->lock);
+
+		if (vnode->lock_state != AFS_VNODE_LOCK_EXTENDING)
+			goto again;
+		afs_set_lock_state(vnode, AFS_VNODE_LOCK_GRANTED);
+
+		if (ret != 0)
+			queue_delayed_work(afs_lock_manager, &vnode->lock_work,
+					   HZ * 10);
+		spin_unlock(&vnode->lock);
+		_leave(" [ext]");
+		return;
+
+	/* If we're waiting for a callback to indicate lock release, we can't
+	 * actually rely on this, so need to recheck at regular intervals.  The
+	 * problem is that the server might not notify us if the lock just
+	 * expires (say because a client died) rather than being explicitly
+	 * released.
+	 */
+	case AFS_VNODE_LOCK_WAITING_FOR_CB:
+		_debug("retry");
+		afs_next_locker(vnode, 0);
+		spin_unlock(&vnode->lock);
+		return;
+
+	default:
+		/* Looks like a lock request was withdrawn. */
+		spin_unlock(&vnode->lock);
+		_leave(" [no]");
+		return;
+	}
+}
+
+/*
+ * pass responsibility for the unlocking of a vnode on the server to the
+ * manager thread, lest a pending signal in the calling thread interrupt
+ * AF_RXRPC
+ * - the caller must hold the vnode lock
+ */
+static void afs_defer_unlock(struct afs_vnode *vnode)
+{
+	_enter("%u", vnode->lock_state);
+
+	if (list_empty(&vnode->granted_locks) &&
+	    (vnode->lock_state == AFS_VNODE_LOCK_GRANTED ||
+	     vnode->lock_state == AFS_VNODE_LOCK_EXTENDING)) {
+		cancel_delayed_work(&vnode->lock_work);
+
+		afs_set_lock_state(vnode, AFS_VNODE_LOCK_NEED_UNLOCK);
+		queue_delayed_work(afs_lock_manager, &vnode->lock_work, 0);
+	}
+}
+
+/*
+ * Check that our view of the file metadata is up to date and check to see
+ * whether we think that we have a locking permit.
+ */
+static int afs_do_setlk_check(struct afs_vnode *vnode, struct key *key,
+			      afs_lock_type_t type, bool can_sleep)
+{
+	afs_access_t access;
+	int ret;
+
+	/* Make sure we've got a callback on this file and that our view of the
+	 * data version is up to date.
+	 */
+	ret = afs_validate(vnode, key);
+	if (ret < 0)
+		return ret;
+
+	/* Check the permission set to see if we're actually going to be
+	 * allowed to get a lock on this file.
+	 */
+	ret = afs_check_permit(vnode, key, &access);
+	if (ret < 0)
+		return ret;
+
+	/* At a rough estimation, you need LOCK, WRITE or INSERT perm to
+	 * read-lock a file and WRITE or INSERT perm to write-lock a file.
+	 *
+	 * We can't rely on the server to do this for us since if we want to
+	 * share a read lock that we already have, we won't go the server.
+	 */
+	if (type == AFS_LOCK_READ) {
+		if (!(access & (AFS_ACE_INSERT | AFS_ACE_WRITE | AFS_ACE_LOCK)))
+			return -EACCES;
+		if (vnode->status.lock_count == -1 && !can_sleep)
+			return -EAGAIN; /* Write locked */
+	} else {
+		if (!(access & (AFS_ACE_INSERT | AFS_ACE_WRITE)))
+			return -EACCES;
+		if (vnode->status.lock_count != 0 && !can_sleep)
+			return -EAGAIN; /* Locked */
+	}
+
+	return 0;
+}
+
+/*
+ * request a lock on a file on the server
+ */
+static int afs_do_setlk(struct file *file, struct file_lock *fl)
+{
+	struct inode *inode = locks_inode(file);
+	struct afs_vnode *vnode = AFS_FS_I(inode);
+	afs_lock_type_t type;
+	struct key *key = afs_file_key(file);
+	int ret;
+
+	_enter("{%x:%u},%u", vnode->fid.vid, vnode->fid.vnode, fl->fl_type);
+
+	fl->fl_ops = &afs_lock_ops;
+	INIT_LIST_HEAD(&fl->fl_u.afs.link);
+	fl->fl_u.afs.state = AFS_LOCK_PENDING;
+
+	type = (fl->fl_type == F_RDLCK) ? AFS_LOCK_READ : AFS_LOCK_WRITE;
+
+	ret = afs_do_setlk_check(vnode, key, type, fl->fl_flags & FL_SLEEP);
+	if (ret < 0)
+		return ret;
+
+	spin_lock(&vnode->lock);
+	list_add_tail(&fl->fl_u.afs.link, &vnode->pending_locks);
+
+	/* If we've already got a lock on the server then try to move to having
+	 * the VFS grant the requested lock.  Note that this means that other
+	 * clients may get starved out.
+	 */
+	_debug("try %u", vnode->lock_state);
+	if (vnode->lock_state == AFS_VNODE_LOCK_GRANTED) {
+		if (type == AFS_LOCK_READ) {
+			_debug("instant readlock");
+			list_move_tail(&fl->fl_u.afs.link, &vnode->granted_locks);
+			fl->fl_u.afs.state = AFS_LOCK_GRANTED;
+			goto vnode_is_locked_u;
+		}
+
+		if (vnode->lock_type == AFS_LOCK_WRITE) {
+			_debug("instant writelock");
+			list_move_tail(&fl->fl_u.afs.link, &vnode->granted_locks);
+			fl->fl_u.afs.state = AFS_LOCK_GRANTED;
+			goto vnode_is_locked_u;
+		}
+	}
+
+	if (vnode->lock_state != AFS_VNODE_LOCK_NONE)
+		goto need_to_wait;
+
+try_to_lock:
+	/* We don't have a lock on this vnode and we aren't currently waiting
+	 * for one either, so ask the server for a lock.
+	 *
+	 * Note that we need to be careful if we get interrupted by a signal
+	 * after dispatching the request as we may still get the lock, even
+	 * though we don't wait for the reply (it's not too bad a problem - the
+	 * lock will expire in 5 mins anyway).
+	 */
+	_debug("not locked");
+	vnode->lock_key = key_get(key);
+	vnode->lock_type = type;
+	afs_set_lock_state(vnode, AFS_VNODE_LOCK_SETTING);
+	spin_unlock(&vnode->lock);
+
+	ret = afs_set_lock(vnode, key, type); /* RPC */
+
+	spin_lock(&vnode->lock);
+	switch (ret) {
+	case -EKEYREJECTED:
+	case -EKEYEXPIRED:
+	case -EKEYREVOKED:
+	case -EPERM:
+	case -EACCES:
+		fl->fl_u.afs.state = ret;
+		list_del_init(&fl->fl_u.afs.link);
+		afs_next_locker(vnode, ret);
+		goto error_unlock;
+
+	default:
+		fl->fl_u.afs.state = ret;
+		list_del_init(&fl->fl_u.afs.link);
+		afs_next_locker(vnode, 0);
+		goto error_unlock;
+
+	case -EWOULDBLOCK:
+		/* The server doesn't have a lock-waiting queue, so the client
+		 * will have to retry.  The server will break the outstanding
+		 * callbacks on a file when a lock is released.
+		 */
+		_debug("would block");
+		ASSERT(list_empty(&vnode->granted_locks));
+		ASSERTCMP(vnode->pending_locks.next, ==, &fl->fl_u.afs.link);
+		goto lock_is_contended;
+
+	case 0:
+		_debug("acquired");
+		afs_set_lock_state(vnode, AFS_VNODE_LOCK_GRANTED);
+		afs_grant_locks(vnode);
+		goto vnode_is_locked_u;
+	}
+
+vnode_is_locked_u:
+	spin_unlock(&vnode->lock);
+vnode_is_locked:
+	/* the lock has been granted by the server... */
+	ASSERTCMP(fl->fl_u.afs.state, ==, AFS_LOCK_GRANTED);
+
+	/* ... but the VFS still needs to distribute access on this client. */
+	ret = locks_lock_file_wait(file, fl);
+	if (ret < 0)
+		goto vfs_rejected_lock;
+
+	/* Again, make sure we've got a callback on this file and, again, make
+	 * sure that our view of the data version is up to date (we ignore
+	 * errors incurred here and deal with the consequences elsewhere).
+	 */
+	afs_validate(vnode, key);
+	_leave(" = 0");
+	return 0;
+
+lock_is_contended:
+	if (!(fl->fl_flags & FL_SLEEP)) {
+		list_del_init(&fl->fl_u.afs.link);
+		afs_next_locker(vnode, 0);
+		ret = -EAGAIN;
+		goto error_unlock;
+	}
+
+	afs_set_lock_state(vnode, AFS_VNODE_LOCK_WAITING_FOR_CB);
+	queue_delayed_work(afs_lock_manager, &vnode->lock_work, HZ * 5);
+
+need_to_wait:
+	/* We're going to have to wait.  Either this client doesn't have a lock
+	 * on the server yet and we need to wait for a callback to occur, or
+	 * the client does have a lock on the server, but it's shared and we
+	 * need an exclusive lock.
+	 */
+	spin_unlock(&vnode->lock);
+
+	_debug("sleep");
+	ret = wait_event_interruptible(fl->fl_wait,
+				       fl->fl_u.afs.state != AFS_LOCK_PENDING);
+	_debug("wait = %d", ret);
+
+	if (fl->fl_u.afs.state >= 0 && fl->fl_u.afs.state != AFS_LOCK_GRANTED) {
+		spin_lock(&vnode->lock);
+
+		switch (fl->fl_u.afs.state) {
+		case AFS_LOCK_YOUR_TRY:
+			fl->fl_u.afs.state = AFS_LOCK_PENDING;
+			goto try_to_lock;
+		case AFS_LOCK_PENDING:
+			if (ret > 0) {
+				/* We need to retry the lock.  We may not be
+				 * notified by the server if it just expired
+				 * rather than being released.
+				 */
+				ASSERTCMP(vnode->lock_state, ==, AFS_VNODE_LOCK_WAITING_FOR_CB);
+				afs_set_lock_state(vnode, AFS_VNODE_LOCK_SETTING);
+				fl->fl_u.afs.state = AFS_LOCK_PENDING;
+				goto try_to_lock;
+			}
+			goto error_unlock;
+		case AFS_LOCK_GRANTED:
+		default:
+			break;
+		}
+
+		spin_unlock(&vnode->lock);
+	}
+
+	if (fl->fl_u.afs.state == AFS_LOCK_GRANTED)
+		goto vnode_is_locked;
+	ret = fl->fl_u.afs.state;
+	goto error;
+
+vfs_rejected_lock:
+	/* The VFS rejected the lock we just obtained, so we have to discard
+	 * what we just got.  We defer this to the lock manager work item to
+	 * deal with.
+	 */
+	_debug("vfs refused %d", ret);
+	spin_lock(&vnode->lock);
+	list_del_init(&fl->fl_u.afs.link);
+	afs_defer_unlock(vnode);
+
+error_unlock:
+	spin_unlock(&vnode->lock);
+error:
+	_leave(" = %d", ret);
+	return ret;
+}
+
+/*
+ * unlock on a file on the server
+ */
+static int afs_do_unlk(struct file *file, struct file_lock *fl)
+{
+	struct afs_vnode *vnode = AFS_FS_I(locks_inode(file));
+	int ret;
+
+	_enter("{%x:%u},%u", vnode->fid.vid, vnode->fid.vnode, fl->fl_type);
+
+	/* Flush all pending writes before doing anything with locks. */
+	vfs_fsync(file, 0);
+
+	ret = locks_lock_file_wait(file, fl);
+	_leave(" = %d [%u]", ret, vnode->lock_state);
+	return ret;
+}
+
+/*
+ * return information about a lock we currently hold, if indeed we hold one
+ */
+static int afs_do_getlk(struct file *file, struct file_lock *fl)
+{
+	struct afs_vnode *vnode = AFS_FS_I(locks_inode(file));
+	struct key *key = afs_file_key(file);
+	int ret, lock_count;
+
+	_enter("");
+
+	fl->fl_type = F_UNLCK;
+
+	/* check local lock records first */
+	posix_test_lock(file, fl);
+	if (fl->fl_type == F_UNLCK) {
+		/* no local locks; consult the server */
+		ret = afs_fetch_status(vnode, key, false);
+		if (ret < 0)
+			goto error;
+
+		lock_count = READ_ONCE(vnode->status.lock_count);
+		if (lock_count != 0) {
+			if (lock_count > 0)
+				fl->fl_type = F_RDLCK;
+			else
+				fl->fl_type = F_WRLCK;
+			fl->fl_start = 0;
+			fl->fl_end = OFFSET_MAX;
+			fl->fl_pid = 0;
+		}
+	}
+
+	ret = 0;
+error:
+	_leave(" = %d [%hd]", ret, fl->fl_type);
+	return ret;
+}
+
+/*
+ * manage POSIX locks on a file
+ */
+int afs_lock(struct file *file, int cmd, struct file_lock *fl)
+{
+	struct afs_vnode *vnode = AFS_FS_I(locks_inode(file));
+
+	_enter("{%x:%u},%d,{t=%x,fl=%x,r=%Ld:%Ld}",
+	       vnode->fid.vid, vnode->fid.vnode, cmd,
+	       fl->fl_type, fl->fl_flags,
+	       (long long) fl->fl_start, (long long) fl->fl_end);
+
+	/* AFS doesn't support mandatory locks */
+	if (__mandatory_lock(&vnode->vfs_inode) && fl->fl_type != F_UNLCK)
+		return -ENOLCK;
+
+	if (IS_GETLK(cmd))
+		return afs_do_getlk(file, fl);
+	if (fl->fl_type == F_UNLCK)
+		return afs_do_unlk(file, fl);
+	return afs_do_setlk(file, fl);
+}
+
+/*
+ * manage FLOCK locks on a file
+ */
+int afs_flock(struct file *file, int cmd, struct file_lock *fl)
+{
+	struct afs_vnode *vnode = AFS_FS_I(locks_inode(file));
+
+	_enter("{%x:%u},%d,{t=%x,fl=%x}",
+	       vnode->fid.vid, vnode->fid.vnode, cmd,
+	       fl->fl_type, fl->fl_flags);
+
+	/*
+	 * No BSD flocks over NFS allowed.
+	 * Note: we could try to fake a POSIX lock request here by
+	 * using ((u32) filp | 0x80000000) or some such as the pid.
+	 * Not sure whether that would be unique, though, or whether
+	 * that would break in other places.
+	 */
+	if (!(fl->fl_flags & FL_FLOCK))
+		return -ENOLCK;
+
+	/* we're simulating flock() locks using posix locks on the server */
+	if (fl->fl_type == F_UNLCK)
+		return afs_do_unlk(file, fl);
+	return afs_do_setlk(file, fl);
+}
+
+/*
+ * the POSIX lock management core VFS code copies the lock record and adds the
+ * copy into its own list, so we need to add that copy to the vnode's lock
+ * queue in the same place as the original (which will be deleted shortly
+ * after)
+ */
+static void afs_fl_copy_lock(struct file_lock *new, struct file_lock *fl)
+{
+	struct afs_vnode *vnode = AFS_FS_I(locks_inode(fl->fl_file));
+
+	_enter("");
+
+	spin_lock(&vnode->lock);
+	list_add(&new->fl_u.afs.link, &fl->fl_u.afs.link);
+	spin_unlock(&vnode->lock);
+}
+
+/*
+ * need to remove this lock from the vnode queue when it's removed from the
+ * VFS's list
+ */
+static void afs_fl_release_private(struct file_lock *fl)
+{
+	struct afs_vnode *vnode = AFS_FS_I(locks_inode(fl->fl_file));
+
+	_enter("");
+
+	spin_lock(&vnode->lock);
+
+	list_del_init(&fl->fl_u.afs.link);
+	if (list_empty(&vnode->granted_locks))
+		afs_defer_unlock(vnode);
+
+	_debug("state %u for %p", vnode->lock_state, vnode);
+	spin_unlock(&vnode->lock);
+}