fs/afs/fsclient.c - LeafOS-Devices/android_kernel_samsung_exynos9820 - Gitiles

 /* AFS File Server client stubs
  *
  * Copyright (C) 2002, 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 <linux/init.h>
 #include <linux/sched.h>
 #include <linux/circ_buf.h>
 #include "internal.h"
 #include "afs_fs.h"

 /*
  * decode an AFSFetchStatus block
  */
 static void xdr_decode_AFSFetchStatus(const __be32 **_bp,
 				      struct afs_vnode *vnode)
 {
 	const __be32 *bp = *_bp;
 	umode_t mode;
 	u64 data_version;
 	u32 changed = 0; /* becomes non-zero if ctime-type changes seen */

 #define EXTRACT(DST)				\
 	do {					\
 		u32 x = ntohl(*bp++);		\
 		changed |= DST - x;		\
 		DST = x;			\
 	} while (0)

 	vnode->status.if_version = ntohl(*bp++);
 	EXTRACT(vnode->status.type);
 	vnode->status.nlink = ntohl(*bp++);
 	EXTRACT(vnode->status.size);
 	data_version = ntohl(*bp++);
 	EXTRACT(vnode->status.author);
 	EXTRACT(vnode->status.owner);
 	EXTRACT(vnode->status.caller_access); /* call ticket dependent */
 	EXTRACT(vnode->status.anon_access);
 	EXTRACT(vnode->status.mode);
 	vnode->status.parent.vid = vnode->fid.vid;
 	EXTRACT(vnode->status.parent.vnode);
 	EXTRACT(vnode->status.parent.unique);
 	bp++; /* seg size */
 	vnode->status.mtime_client = ntohl(*bp++);
 	vnode->status.mtime_server = ntohl(*bp++);
 	bp++; /* group */
 	bp++; /* sync counter */
 	data_version |= (u64) ntohl(*bp++) << 32;
 	bp++; /* spare2 */
 	bp++; /* spare3 */
 	bp++; /* spare4 */
 	*_bp = bp;

 	if (changed) {
 		_debug("vnode changed");
 		set_bit(AFS_VNODE_CHANGED, &vnode->flags);
 		vnode->vfs_inode.i_uid		= vnode->status.owner;
 		vnode->vfs_inode.i_size		= vnode->status.size;
 		vnode->vfs_inode.i_version	= vnode->fid.unique;

 		vnode->status.mode &= S_IALLUGO;
 		mode = vnode->vfs_inode.i_mode;
 		mode &= ~S_IALLUGO;
 		mode |= vnode->status.mode;
 		vnode->vfs_inode.i_mode = mode;
 	}

 	_debug("vnode time %lx, %lx",
 	       vnode->status.mtime_client, vnode->status.mtime_server);
 	vnode->vfs_inode.i_ctime.tv_sec	= vnode->status.mtime_server;
 	vnode->vfs_inode.i_mtime	= vnode->vfs_inode.i_ctime;
 	vnode->vfs_inode.i_atime	= vnode->vfs_inode.i_ctime;

 	if (vnode->status.data_version != data_version) {
 		_debug("vnode modified %llx", data_version);
 		vnode->status.data_version = data_version;
 		set_bit(AFS_VNODE_MODIFIED, &vnode->flags);
 		set_bit(AFS_VNODE_ZAP_DATA, &vnode->flags);
 	}
 }

 /*
  * decode an AFSCallBack block
  */
 static void xdr_decode_AFSCallBack(const __be32 **_bp, struct afs_vnode *vnode)
 {
 	const __be32 *bp = *_bp;

 	vnode->cb_version	= ntohl(*bp++);
 	vnode->cb_expiry	= ntohl(*bp++);
 	vnode->cb_type		= ntohl(*bp++);
 	vnode->cb_expires	= vnode->cb_expiry + get_seconds();
 	*_bp = bp;
 }

 /*
  * decode an AFSVolSync block
  */
 static void xdr_decode_AFSVolSync(const __be32 **_bp,
 				  struct afs_volsync *volsync)
 {
 	const __be32 *bp = *_bp;

 	volsync->creation = ntohl(*bp++);
 	bp++; /* spare2 */
 	bp++; /* spare3 */
 	bp++; /* spare4 */
 	bp++; /* spare5 */
 	bp++; /* spare6 */
 	*_bp = bp;
 }

 /*
  * deliver reply data to an FS.FetchStatus
  */
 static int afs_deliver_fs_fetch_status(struct afs_call *call,
 				       struct sk_buff *skb, bool last)
 {
 	const __be32 *bp;

 	_enter(",,%u", last);

 	afs_transfer_reply(call, skb);
 	if (!last)
 		return 0;

 	if (call->reply_size != call->reply_max)
 		return -EBADMSG;

 	/* unmarshall the reply once we've received all of it */
 	bp = call->buffer;
 	xdr_decode_AFSFetchStatus(&bp, call->reply);
 	xdr_decode_AFSCallBack(&bp, call->reply);
 	if (call->reply2)
 		xdr_decode_AFSVolSync(&bp, call->reply2);

 	_leave(" = 0 [done]");
 	return 0;
 }

 /*
  * FS.FetchStatus operation type
  */
 static const struct afs_call_type afs_RXFSFetchStatus = {
 	.name		= "FS.FetchStatus",
 	.deliver	= afs_deliver_fs_fetch_status,
 	.abort_to_error	= afs_abort_to_error,
 	.destructor	= afs_flat_call_destructor,
 };

 /*
  * fetch the status information for a file
  */
 int afs_fs_fetch_file_status(struct afs_server *server,
 			     struct key *key,
 			     struct afs_vnode *vnode,
 			     struct afs_volsync *volsync,
 			     const struct afs_wait_mode *wait_mode)
 {
 	struct afs_call *call;
 	__be32 *bp;

 	_enter(",%x,,,", key_serial(key));

 	call = afs_alloc_flat_call(&afs_RXFSFetchStatus, 16, 120);
 	if (!call)
 		return -ENOMEM;

 	call->key = key;
 	call->reply = vnode;
 	call->reply2 = volsync;
 	call->service_id = FS_SERVICE;
 	call->port = htons(AFS_FS_PORT);

 	/* marshall the parameters */
 	bp = call->request;
 	bp[0] = htonl(FSFETCHSTATUS);
 	bp[1] = htonl(vnode->fid.vid);
 	bp[2] = htonl(vnode->fid.vnode);
 	bp[3] = htonl(vnode->fid.unique);

 	return afs_make_call(&server->addr, call, GFP_NOFS, wait_mode);
 }

 /*
  * deliver reply data to an FS.FetchData
  */
 static int afs_deliver_fs_fetch_data(struct afs_call *call,
 				     struct sk_buff *skb, bool last)
 {
 	const __be32 *bp;
 	struct page *page;
 	void *buffer;
 	int ret;

 	_enter("{%u},{%u},%d", call->unmarshall, skb->len, last);

 	switch (call->unmarshall) {
 	case 0:
 		call->offset = 0;
 		call->unmarshall++;

 		/* extract the returned data length */
 	case 1:
 		_debug("extract data length");
 		ret = afs_extract_data(call, skb, last, &call->tmp, 4);
 		switch (ret) {
 		case 0:		break;
 		case -EAGAIN:	return 0;
 		default:	return ret;
 		}

 		call->count = ntohl(call->tmp);
 		_debug("DATA length: %u", call->count);
 		if (call->count > PAGE_SIZE)
 			return -EBADMSG;
 		call->offset = 0;
 		call->unmarshall++;

 		if (call->count < PAGE_SIZE) {
 			buffer = kmap_atomic(call->reply3, KM_USER0);
 			memset(buffer + PAGE_SIZE - call->count, 0,
 			       call->count);
 			kunmap_atomic(buffer, KM_USER0);
 		}

 		/* extract the returned data */
 	case 2:
 		_debug("extract data");
 		page = call->reply3;
 		buffer = kmap_atomic(page, KM_USER0);
 		ret = afs_extract_data(call, skb, last, buffer, call->count);
 		kunmap_atomic(buffer, KM_USER0);
 		switch (ret) {
 		case 0:		break;
 		case -EAGAIN:	return 0;
 		default:	return ret;
 		}

 		call->offset = 0;
 		call->unmarshall++;

 		/* extract the metadata */
 	case 3:
 		ret = afs_extract_data(call, skb, last, call->buffer, 120);
 		switch (ret) {
 		case 0:		break;
 		case -EAGAIN:	return 0;
 		default:	return ret;
 		}

 		bp = call->buffer;
 		xdr_decode_AFSFetchStatus(&bp, call->reply);
 		xdr_decode_AFSCallBack(&bp, call->reply);
 		if (call->reply2)
 			xdr_decode_AFSVolSync(&bp, call->reply2);

 		call->offset = 0;
 		call->unmarshall++;

 	case 4:
 		_debug("trailer");
 		if (skb->len != 0)
 			return -EBADMSG;
 		break;
 	}

 	if (!last)
 		return 0;

 	_leave(" = 0 [done]");
 	return 0;
 }

 /*
  * FS.FetchData operation type
  */
 static const struct afs_call_type afs_RXFSFetchData = {
 	.name		= "FS.FetchData",
 	.deliver	= afs_deliver_fs_fetch_data,
 	.abort_to_error	= afs_abort_to_error,
 	.destructor	= afs_flat_call_destructor,
 };

 /*
  * fetch data from a file
  */
 int afs_fs_fetch_data(struct afs_server *server,
 		      struct key *key,
 		      struct afs_vnode *vnode,
 		      off_t offset, size_t length,
 		      struct page *buffer,
 		      struct afs_volsync *volsync,
 		      const struct afs_wait_mode *wait_mode)
 {
 	struct afs_call *call;
 	__be32 *bp;

 	_enter("");

 	call = afs_alloc_flat_call(&afs_RXFSFetchData, 24, 120);
 	if (!call)
 		return -ENOMEM;

 	call->key = key;
 	call->reply = vnode;
 	call->reply2 = volsync;
 	call->reply3 = buffer;
 	call->service_id = FS_SERVICE;
 	call->port = htons(AFS_FS_PORT);

 	/* marshall the parameters */
 	bp = call->request;
 	bp[0] = htonl(FSFETCHDATA);
 	bp[1] = htonl(vnode->fid.vid);
 	bp[2] = htonl(vnode->fid.vnode);
 	bp[3] = htonl(vnode->fid.unique);
 	bp[4] = htonl(offset);
 	bp[5] = htonl(length);

 	return afs_make_call(&server->addr, call, GFP_NOFS, wait_mode);
 }

 /*
  * deliver reply data to an FS.GiveUpCallBacks
  */
 static int afs_deliver_fs_give_up_callbacks(struct afs_call *call,
 					    struct sk_buff *skb, bool last)
 {
 	_enter(",{%u},%d", skb->len, last);

 	if (skb->len > 0)
 		return -EBADMSG; /* shouldn't be any reply data */
 	return 0;
 }

 /*
  * FS.GiveUpCallBacks operation type
  */
 static const struct afs_call_type afs_RXFSGiveUpCallBacks = {
 	.name		= "FS.GiveUpCallBacks",
 	.deliver	= afs_deliver_fs_give_up_callbacks,
 	.abort_to_error	= afs_abort_to_error,
 	.destructor	= afs_flat_call_destructor,
 };

 /*
  * give up a set of callbacks
  * - the callbacks are held in the server->cb_break ring
  */
 int afs_fs_give_up_callbacks(struct afs_server *server,
 			     const struct afs_wait_mode *wait_mode)
 {
 	struct afs_call *call;
 	size_t ncallbacks;
 	__be32 *bp, *tp;
 	int loop;

 	ncallbacks = CIRC_CNT(server->cb_break_head, server->cb_break_tail,
 			      ARRAY_SIZE(server->cb_break));

 	_enter("{%zu},", ncallbacks);

 	if (ncallbacks == 0)
 		return 0;
 	if (ncallbacks > AFSCBMAX)
 		ncallbacks = AFSCBMAX;

 	_debug("break %zu callbacks", ncallbacks);

 	call = afs_alloc_flat_call(&afs_RXFSGiveUpCallBacks,
 				   12 + ncallbacks * 6 * 4, 0);
 	if (!call)
 		return -ENOMEM;

 	call->service_id = FS_SERVICE;
 	call->port = htons(AFS_FS_PORT);

 	/* marshall the parameters */
 	bp = call->request;
 	tp = bp + 2 + ncallbacks * 3;
 	*bp++ = htonl(FSGIVEUPCALLBACKS);
 	*bp++ = htonl(ncallbacks);
 	*tp++ = htonl(ncallbacks);

 	atomic_sub(ncallbacks, &server->cb_break_n);
 	for (loop = ncallbacks; loop > 0; loop--) {
 		struct afs_callback *cb =
 			&server->cb_break[server->cb_break_tail];

 		*bp++ = htonl(cb->fid.vid);
 		*bp++ = htonl(cb->fid.vnode);
 		*bp++ = htonl(cb->fid.unique);
 		*tp++ = htonl(cb->version);
 		*tp++ = htonl(cb->expiry);
 		*tp++ = htonl(cb->type);
 		smp_mb();
 		server->cb_break_tail =
 			(server->cb_break_tail + 1) &
 			(ARRAY_SIZE(server->cb_break) - 1);
 	}

 	ASSERT(ncallbacks > 0);
 	wake_up_nr(&server->cb_break_waitq, ncallbacks);

 	return afs_make_call(&server->addr, call, GFP_NOFS, wait_mode);
 }
	/* AFS File Server client stubs
	*
	* Copyright (C) 2002, 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 <linux/init.h>
	#include <linux/sched.h>
	#include <linux/circ_buf.h>
	#include "internal.h"
	#include "afs_fs.h"

	/*
	* decode an AFSFetchStatus block
	*/
	static void xdr_decode_AFSFetchStatus(const __be32 **_bp,
	struct afs_vnode *vnode)
	{
	const __be32 bp = _bp;
	umode_t mode;
	u64 data_version;
	u32 changed = 0; /* becomes non-zero if ctime-type changes seen */

	#define EXTRACT(DST) \
	do { \
	u32 x = ntohl(*bp++); \
	changed \|= DST - x; \
	DST = x; \
	} while (0)

	vnode->status.if_version = ntohl(*bp++);
	EXTRACT(vnode->status.type);
	vnode->status.nlink = ntohl(*bp++);
	EXTRACT(vnode->status.size);
	data_version = ntohl(*bp++);
	EXTRACT(vnode->status.author);
	EXTRACT(vnode->status.owner);
	EXTRACT(vnode->status.caller_access); /* call ticket dependent */
	EXTRACT(vnode->status.anon_access);
	EXTRACT(vnode->status.mode);
	vnode->status.parent.vid = vnode->fid.vid;
	EXTRACT(vnode->status.parent.vnode);
	EXTRACT(vnode->status.parent.unique);
	bp++; /* seg size */
	vnode->status.mtime_client = ntohl(*bp++);
	vnode->status.mtime_server = ntohl(*bp++);
	bp++; /* group */
	bp++; /* sync counter */
	data_version \|= (u64) ntohl(*bp++) << 32;
	bp++; /* spare2 */
	bp++; /* spare3 */
	bp++; /* spare4 */
	*_bp = bp;

	if (changed) {
	_debug("vnode changed");
	set_bit(AFS_VNODE_CHANGED, &vnode->flags);
	vnode->vfs_inode.i_uid = vnode->status.owner;
	vnode->vfs_inode.i_size = vnode->status.size;
	vnode->vfs_inode.i_version = vnode->fid.unique;

	vnode->status.mode &= S_IALLUGO;
	mode = vnode->vfs_inode.i_mode;
	mode &= ~S_IALLUGO;
	mode \|= vnode->status.mode;
	vnode->vfs_inode.i_mode = mode;
	}

	_debug("vnode time %lx, %lx",
	vnode->status.mtime_client, vnode->status.mtime_server);
	vnode->vfs_inode.i_ctime.tv_sec = vnode->status.mtime_server;
	vnode->vfs_inode.i_mtime = vnode->vfs_inode.i_ctime;
	vnode->vfs_inode.i_atime = vnode->vfs_inode.i_ctime;

	if (vnode->status.data_version != data_version) {
	_debug("vnode modified %llx", data_version);
	vnode->status.data_version = data_version;
	set_bit(AFS_VNODE_MODIFIED, &vnode->flags);
	set_bit(AFS_VNODE_ZAP_DATA, &vnode->flags);
	}
	}

	/*
	* decode an AFSCallBack block
	*/
	static void xdr_decode_AFSCallBack(const __be32 *_bp, struct afs_vnode vnode)
	{
	const __be32 bp = _bp;

	vnode->cb_version = ntohl(*bp++);
	vnode->cb_expiry = ntohl(*bp++);
	vnode->cb_type = ntohl(*bp++);
	vnode->cb_expires = vnode->cb_expiry + get_seconds();
	*_bp = bp;
	}

	/*
	* decode an AFSVolSync block
	*/
	static void xdr_decode_AFSVolSync(const __be32 **_bp,
	struct afs_volsync *volsync)
	{
	const __be32 bp = _bp;

	volsync->creation = ntohl(*bp++);
	bp++; /* spare2 */
	bp++; /* spare3 */
	bp++; /* spare4 */
	bp++; /* spare5 */
	bp++; /* spare6 */
	*_bp = bp;
	}

	/*
	* deliver reply data to an FS.FetchStatus
	*/
	static int afs_deliver_fs_fetch_status(struct afs_call *call,
	struct sk_buff *skb, bool last)
	{
	const __be32 *bp;

	_enter(",,%u", last);

	afs_transfer_reply(call, skb);
	if (!last)
	return 0;

	if (call->reply_size != call->reply_max)
	return -EBADMSG;

	/* unmarshall the reply once we've received all of it */
	bp = call->buffer;
	xdr_decode_AFSFetchStatus(&bp, call->reply);
	xdr_decode_AFSCallBack(&bp, call->reply);
	if (call->reply2)
	xdr_decode_AFSVolSync(&bp, call->reply2);

	_leave(" = 0 [done]");
	return 0;
	}

	/*
	* FS.FetchStatus operation type
	*/
	static const struct afs_call_type afs_RXFSFetchStatus = {
	.name = "FS.FetchStatus",
	.deliver = afs_deliver_fs_fetch_status,
	.abort_to_error = afs_abort_to_error,
	.destructor = afs_flat_call_destructor,
	};

	/*
	* fetch the status information for a file
	*/
	int afs_fs_fetch_file_status(struct afs_server *server,
	struct key *key,
	struct afs_vnode *vnode,
	struct afs_volsync *volsync,
	const struct afs_wait_mode *wait_mode)
	{
	struct afs_call *call;
	__be32 *bp;

	_enter(",%x,,,", key_serial(key));

	call = afs_alloc_flat_call(&afs_RXFSFetchStatus, 16, 120);
	if (!call)
	return -ENOMEM;

	call->key = key;
	call->reply = vnode;
	call->reply2 = volsync;
	call->service_id = FS_SERVICE;
	call->port = htons(AFS_FS_PORT);

	/* marshall the parameters */
	bp = call->request;
	bp[0] = htonl(FSFETCHSTATUS);
	bp[1] = htonl(vnode->fid.vid);
	bp[2] = htonl(vnode->fid.vnode);
	bp[3] = htonl(vnode->fid.unique);

	return afs_make_call(&server->addr, call, GFP_NOFS, wait_mode);
	}

	/*
	* deliver reply data to an FS.FetchData
	*/
	static int afs_deliver_fs_fetch_data(struct afs_call *call,
	struct sk_buff *skb, bool last)
	{
	const __be32 *bp;
	struct page *page;
	void *buffer;
	int ret;

	_enter("{%u},{%u},%d", call->unmarshall, skb->len, last);

	switch (call->unmarshall) {
	case 0:
	call->offset = 0;
	call->unmarshall++;

	/* extract the returned data length */
	case 1:
	_debug("extract data length");
	ret = afs_extract_data(call, skb, last, &call->tmp, 4);
	switch (ret) {
	case 0: break;
	case -EAGAIN: return 0;
	default: return ret;
	}

	call->count = ntohl(call->tmp);
	_debug("DATA length: %u", call->count);
	if (call->count > PAGE_SIZE)
	return -EBADMSG;
	call->offset = 0;
	call->unmarshall++;

	if (call->count < PAGE_SIZE) {
	buffer = kmap_atomic(call->reply3, KM_USER0);
	memset(buffer + PAGE_SIZE - call->count, 0,
	call->count);
	kunmap_atomic(buffer, KM_USER0);
	}

	/* extract the returned data */
	case 2:
	_debug("extract data");
	page = call->reply3;
	buffer = kmap_atomic(page, KM_USER0);
	ret = afs_extract_data(call, skb, last, buffer, call->count);
	kunmap_atomic(buffer, KM_USER0);
	switch (ret) {
	case 0: break;
	case -EAGAIN: return 0;
	default: return ret;
	}

	call->offset = 0;
	call->unmarshall++;

	/* extract the metadata */
	case 3:
	ret = afs_extract_data(call, skb, last, call->buffer, 120);
	switch (ret) {
	case 0: break;
	case -EAGAIN: return 0;
	default: return ret;
	}

	bp = call->buffer;
	xdr_decode_AFSFetchStatus(&bp, call->reply);
	xdr_decode_AFSCallBack(&bp, call->reply);
	if (call->reply2)
	xdr_decode_AFSVolSync(&bp, call->reply2);

	call->offset = 0;
	call->unmarshall++;

	case 4:
	_debug("trailer");
	if (skb->len != 0)
	return -EBADMSG;
	break;
	}

	if (!last)
	return 0;

	_leave(" = 0 [done]");
	return 0;
	}

	/*
	* FS.FetchData operation type
	*/
	static const struct afs_call_type afs_RXFSFetchData = {
	.name = "FS.FetchData",
	.deliver = afs_deliver_fs_fetch_data,
	.abort_to_error = afs_abort_to_error,
	.destructor = afs_flat_call_destructor,
	};

	/*
	* fetch data from a file
	*/
	int afs_fs_fetch_data(struct afs_server *server,
	struct key *key,
	struct afs_vnode *vnode,
	off_t offset, size_t length,
	struct page *buffer,
	struct afs_volsync *volsync,
	const struct afs_wait_mode *wait_mode)
	{
	struct afs_call *call;
	__be32 *bp;

	_enter("");

	call = afs_alloc_flat_call(&afs_RXFSFetchData, 24, 120);
	if (!call)
	return -ENOMEM;

	call->key = key;
	call->reply = vnode;
	call->reply2 = volsync;
	call->reply3 = buffer;
	call->service_id = FS_SERVICE;
	call->port = htons(AFS_FS_PORT);

	/* marshall the parameters */
	bp = call->request;
	bp[0] = htonl(FSFETCHDATA);
	bp[1] = htonl(vnode->fid.vid);
	bp[2] = htonl(vnode->fid.vnode);
	bp[3] = htonl(vnode->fid.unique);
	bp[4] = htonl(offset);
	bp[5] = htonl(length);

	return afs_make_call(&server->addr, call, GFP_NOFS, wait_mode);
	}

	/*
	* deliver reply data to an FS.GiveUpCallBacks
	*/
	static int afs_deliver_fs_give_up_callbacks(struct afs_call *call,
	struct sk_buff *skb, bool last)
	{
	_enter(",{%u},%d", skb->len, last);

	if (skb->len > 0)
	return -EBADMSG; /* shouldn't be any reply data */
	return 0;
	}

	/*
	* FS.GiveUpCallBacks operation type
	*/
	static const struct afs_call_type afs_RXFSGiveUpCallBacks = {
	.name = "FS.GiveUpCallBacks",
	.deliver = afs_deliver_fs_give_up_callbacks,
	.abort_to_error = afs_abort_to_error,
	.destructor = afs_flat_call_destructor,
	};

	/*
	* give up a set of callbacks
	* - the callbacks are held in the server->cb_break ring
	*/
	int afs_fs_give_up_callbacks(struct afs_server *server,
	const struct afs_wait_mode *wait_mode)
	{
	struct afs_call *call;
	size_t ncallbacks;
	__be32 bp, tp;
	int loop;

	ncallbacks = CIRC_CNT(server->cb_break_head, server->cb_break_tail,
	ARRAY_SIZE(server->cb_break));

	_enter("{%zu},", ncallbacks);

	if (ncallbacks == 0)
	return 0;
	if (ncallbacks > AFSCBMAX)
	ncallbacks = AFSCBMAX;

	_debug("break %zu callbacks", ncallbacks);

	call = afs_alloc_flat_call(&afs_RXFSGiveUpCallBacks,
	12 + ncallbacks * 6 * 4, 0);
	if (!call)
	return -ENOMEM;

	call->service_id = FS_SERVICE;
	call->port = htons(AFS_FS_PORT);

	/* marshall the parameters */
	bp = call->request;
	tp = bp + 2 + ncallbacks * 3;
	*bp++ = htonl(FSGIVEUPCALLBACKS);
	*bp++ = htonl(ncallbacks);
	*tp++ = htonl(ncallbacks);

	atomic_sub(ncallbacks, &server->cb_break_n);
	for (loop = ncallbacks; loop > 0; loop--) {
	struct afs_callback *cb =
	&server->cb_break[server->cb_break_tail];

	*bp++ = htonl(cb->fid.vid);
	*bp++ = htonl(cb->fid.vnode);
	*bp++ = htonl(cb->fid.unique);
	*tp++ = htonl(cb->version);
	*tp++ = htonl(cb->expiry);
	*tp++ = htonl(cb->type);
	smp_mb();
	server->cb_break_tail =
	(server->cb_break_tail + 1) &
	(ARRAY_SIZE(server->cb_break) - 1);
	}

	ASSERT(ncallbacks > 0);
	wake_up_nr(&server->cb_break_waitq, ncallbacks);

	return afs_make_call(&server->addr, call, GFP_NOFS, wait_mode);
	}