samba-mirror/source3/smbd/smb2_ioctl_filesys.c

/*
   Unix SMB/CIFS implementation.
   Core SMB2 server

   Copyright (C) Stefan Metzmacher 2009
   Copyright (C) David Disseldorp 2013-2015

   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 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

#include "includes.h"
#include "smbd/smbd.h"
#include "smbd/globals.h"
#include "../libcli/smb/smb_common.h"
#include "../libcli/security/security.h"
#include "../lib/util/tevent_ntstatus.h"
#include "rpc_server/srv_pipe_hnd.h"
#include "include/ntioctl.h"
#include "../librpc/ndr/libndr.h"
#include "librpc/gen_ndr/ndr_ioctl.h"
#include "smb2_ioctl_private.h"

#undef DBGC_CLASS
#define DBGC_CLASS DBGC_SMB2

/*
 * XXX this may reduce dup_extents->byte_count so that it's less than the
 * target file size.
 */
static NTSTATUS fsctl_dup_extents_check_lengths(struct files_struct *src_fsp,
						struct files_struct *dst_fsp,
				struct fsctl_dup_extents_to_file *dup_extents)
{
	NTSTATUS status;

	if ((dup_extents->source_off + dup_extents->byte_count
						< dup_extents->source_off)
	 || (dup_extents->target_off + dup_extents->byte_count
						< dup_extents->target_off)) {
		return NT_STATUS_INVALID_PARAMETER;	/* wrap */
	}

	status = vfs_stat_fsp(src_fsp);
	if (!NT_STATUS_IS_OK(status)) {
		return status;
	}

	/*
	 * XXX vfs_btrfs and vfs_default have size checks in the copychunk
	 * handler, as this needs to be rechecked after the src has potentially
	 * been extended by a previous chunk in the compound copychunk req.
	 */
	if (src_fsp->fsp_name->st.st_ex_size
			< dup_extents->source_off + dup_extents->byte_count) {
		DEBUG(2, ("dup_extents req exceeds src size\n"));
		return NT_STATUS_NOT_SUPPORTED;
	}

	status = vfs_stat_fsp(dst_fsp);
	if (!NT_STATUS_IS_OK(status)) {
		return status;
	}

	if (dst_fsp->fsp_name->st.st_ex_size
			< dup_extents->target_off + dup_extents->byte_count) {

		if (dst_fsp->fsp_name->st.st_ex_size - dup_extents->target_off
					> dst_fsp->fsp_name->st.st_ex_size) {
			return NT_STATUS_INVALID_PARAMETER;	/* wrap */
		}

		/*
		 * this server behaviour is pretty hairy, but we need to match
		 * Windows, so...
		 */
		DEBUG(2, ("dup_extents req exceeds target size, capping\n"));
		dup_extents->byte_count = dst_fsp->fsp_name->st.st_ex_size
						- dup_extents->target_off;
	}

	return NT_STATUS_OK;
}

static NTSTATUS fsctl_dup_extents_check_overlap(struct files_struct *src_fsp,
						struct files_struct *dst_fsp,
				struct fsctl_dup_extents_to_file *dup_extents)
{
	uint64_t src_off_last;
	uint64_t tgt_off_last;

	if (!file_id_equal(&src_fsp->file_id, &dst_fsp->file_id)) {
		/* src and dest refer to different files */
		return NT_STATUS_OK;
	}

	if (dup_extents->byte_count == 0) {
		/* no range to overlap */
		return NT_STATUS_OK;
	}

	/*
	 * [MS-FSCC] 2.3.8 FSCTL_DUPLICATE_EXTENTS_TO_FILE Reply
	 * STATUS_NOT_SUPPORTED:
	 * The source and target destination ranges overlap on the same file.
	 */

	src_off_last = dup_extents->source_off + dup_extents->byte_count - 1;
	if ((dup_extents->target_off >= dup_extents->source_off)
				&& (dup_extents->target_off <= src_off_last)) {
		/*
		 * src: |-----------|
		 * tgt:       |-----------|
		 */
		return NT_STATUS_NOT_SUPPORTED;
	}


	tgt_off_last = dup_extents->target_off + dup_extents->byte_count - 1;
	if ((tgt_off_last >= dup_extents->source_off)
					&& (tgt_off_last <= src_off_last)) {
		/*
		 * src:       |-----------|
		 * tgt: |-----------|
		 */
		return NT_STATUS_NOT_SUPPORTED;
	}

	return NT_STATUS_OK;
}

static NTSTATUS fsctl_dup_extents_check_sparse(struct files_struct *src_fsp,
					       struct files_struct *dst_fsp)
{
	/*
	 * 2.3.8 FSCTL_DUPLICATE_EXTENTS_TO_FILE Reply...
	 * STATUS_NOT_SUPPORTED: Target file is sparse, while source
	 *			 is a non-sparse file.
	 *
	 * WS2016 has the following behaviour (MS are in the process of fixing
	 * the spec):
	 * STATUS_NOT_SUPPORTED is returned if the source is sparse, while the
	 * target is non-sparse. However, if target is sparse while the source
	 * is non-sparse, then FSCTL_DUPLICATE_EXTENTS_TO_FILE completes
	 * successfully.
	 */
	if ((src_fsp->is_sparse) && (!dst_fsp->is_sparse)) {
		return NT_STATUS_NOT_SUPPORTED;
	}

	return NT_STATUS_OK;
}

struct fsctl_dup_extents_state {
	struct tevent_context *ev;
	struct connection_struct *conn;
	struct files_struct *dst_fsp;
	struct fsctl_dup_extents_to_file dup_extents;
};

static void fsctl_dup_extents_offload_read_done(struct tevent_req *subreq);
static void fsctl_dup_extents_vfs_done(struct tevent_req *subreq);

static struct tevent_req *fsctl_dup_extents_send(TALLOC_CTX *mem_ctx,
						 struct tevent_context *ev,
						 struct files_struct *dst_fsp,
						 DATA_BLOB *in_input,
						 struct smbd_smb2_request *smb2req)
{
	struct tevent_req *req = NULL;
	struct tevent_req *subreq = NULL;
	struct fsctl_dup_extents_state *state = NULL;
	uint64_t src_fid_persistent = 0;
	uint64_t src_fid_volatile = 0;
	struct files_struct *src_fsp = NULL;
	int ndr_ret;
	NTSTATUS status;

	req = tevent_req_create(mem_ctx, &state,
				struct fsctl_dup_extents_state);
	if (req == NULL) {
		return NULL;
	}

	if (dst_fsp == NULL) {
		tevent_req_nterror(req, NT_STATUS_INVALID_PARAMETER);
		return tevent_req_post(req, ev);
	}

	*state = (struct fsctl_dup_extents_state) {
		.conn = dst_fsp->conn,
		.ev = ev,
		.dst_fsp = dst_fsp,
	};

	if ((dst_fsp->conn->fs_capabilities
				& FILE_SUPPORTS_BLOCK_REFCOUNTING) == 0) {
		DBG_INFO("FS does not advertise block refcounting support\n");
		tevent_req_nterror(req, NT_STATUS_INVALID_DEVICE_REQUEST);
		return tevent_req_post(req, ev);
	}

	ndr_ret = ndr_pull_struct_blob(in_input, state, &state->dup_extents,
		       (ndr_pull_flags_fn_t)ndr_pull_fsctl_dup_extents_to_file);
	if (ndr_ret != NDR_ERR_SUCCESS) {
		DBG_ERR("failed to unmarshall dup extents to file req\n");
		tevent_req_nterror(req, NT_STATUS_INVALID_PARAMETER);
		return tevent_req_post(req, ev);
	}

	src_fid_persistent = BVAL(state->dup_extents.source_fid, 0);
	src_fid_volatile = BVAL(state->dup_extents.source_fid, 8);
	src_fsp = file_fsp_get(smb2req, src_fid_persistent, src_fid_volatile);
	if ((src_fsp == NULL)
		      || (src_fsp->file_id.devid != dst_fsp->file_id.devid)) {
		/*
		 * [MS-FSCC] 2.3.8 FSCTL_DUPLICATE_EXTENTS_TO_FILE Reply
		 * STATUS_INVALID_PARAMETER:
		 * The FileHandle parameter is either invalid or does not
		 * represent a handle to an opened file on the same volume.
		 *
		 * Windows Server responds with NT_STATUS_INVALID_HANDLE instead
		 * of STATUS_INVALID_PARAMETER here, despite the above spec.
		 */
		DBG_ERR("invalid src_fsp for dup_extents\n");
		tevent_req_nterror(req, NT_STATUS_INVALID_HANDLE);
		return tevent_req_post(req, ev);
	}

	status = fsctl_dup_extents_check_lengths(src_fsp, dst_fsp,
						 &state->dup_extents);
	if (!NT_STATUS_IS_OK(status)) {
		tevent_req_nterror(req, status);
		return tevent_req_post(req, ev);
	}

	if (state->dup_extents.byte_count == 0) {
		DBG_ERR("skipping zero length dup extents\n");
		tevent_req_done(req);
		return tevent_req_post(req, ev);
	}

	status = fsctl_dup_extents_check_overlap(src_fsp, dst_fsp,
						 &state->dup_extents);
	if (!NT_STATUS_IS_OK(status)) {
		tevent_req_nterror(req, status);
		return tevent_req_post(req, ev);
	}

	status = fsctl_dup_extents_check_sparse(src_fsp, dst_fsp);
	if (!NT_STATUS_IS_OK(status)) {
		tevent_req_nterror(req, status);
		return tevent_req_post(req, ev);
	}

	subreq = SMB_VFS_OFFLOAD_READ_SEND(state, ev, src_fsp,
					   FSCTL_DUP_EXTENTS_TO_FILE,
					   0, 0, 0);
	if (tevent_req_nomem(subreq, req)) {
		return tevent_req_post(req, ev);
	}
	tevent_req_set_callback(subreq, fsctl_dup_extents_offload_read_done,
				req);
	return req;
}

static void fsctl_dup_extents_offload_read_done(struct tevent_req *subreq)
{
	struct tevent_req *req = tevent_req_callback_data(
		subreq, struct tevent_req);
	struct fsctl_dup_extents_state *state = tevent_req_data(
		req, struct fsctl_dup_extents_state);
	DATA_BLOB token;
	NTSTATUS status;

	status = SMB_VFS_OFFLOAD_READ_RECV(subreq, state->dst_fsp->conn,
					   state, &token);
	if (tevent_req_nterror(req, status)) {
		return;
	}

	/* tell the VFS to ignore locks across the clone, matching ReFS */
	subreq = SMB_VFS_OFFLOAD_WRITE_SEND(state->dst_fsp->conn,
					    state,
					    state->ev,
					    FSCTL_DUP_EXTENTS_TO_FILE,
					    &token,
					    state->dup_extents.source_off,
					    state->dst_fsp,
					    state->dup_extents.target_off,
					    state->dup_extents.byte_count);
	if (tevent_req_nomem(subreq, req)) {
		return;
	}
	tevent_req_set_callback(subreq, fsctl_dup_extents_vfs_done, req);
	return;
}

static void fsctl_dup_extents_vfs_done(struct tevent_req *subreq)
{
	struct tevent_req *req = tevent_req_callback_data(
		subreq, struct tevent_req);
	struct fsctl_dup_extents_state *state = tevent_req_data(
		req, struct fsctl_dup_extents_state);
	off_t nb_chunk;
	NTSTATUS status;

	status = SMB_VFS_OFFLOAD_WRITE_RECV(state->conn, subreq, &nb_chunk);
	TALLOC_FREE(subreq);
	if (tevent_req_nterror(req, status)) {
		return;
	}

	if (nb_chunk != state->dup_extents.byte_count) {
		tevent_req_nterror(req, NT_STATUS_IO_DEVICE_ERROR);
		return;
	}

	tevent_req_done(req);
}

static NTSTATUS fsctl_dup_extents_recv(struct tevent_req *req)
{
	return tevent_req_simple_recv_ntstatus(req);
}

static NTSTATUS fsctl_get_cmprn(TALLOC_CTX *mem_ctx,
				struct tevent_context *ev,
				struct files_struct *fsp,
				size_t in_max_output,
				DATA_BLOB *out_output)
{
	struct compression_state cmpr_state;
	enum ndr_err_code ndr_ret;
	DATA_BLOB output;
	NTSTATUS status;

	if (fsp == NULL) {
		return NT_STATUS_FILE_CLOSED;
	}

	/* Windows doesn't check for SEC_FILE_READ_ATTRIBUTE permission here */

	ZERO_STRUCT(cmpr_state);
	if (fsp->conn->fs_capabilities & FILE_FILE_COMPRESSION) {
		status = SMB_VFS_GET_COMPRESSION(fsp->conn,
						 mem_ctx,
						 fsp,
						 NULL,
						 &cmpr_state.format);
		if (!NT_STATUS_IS_OK(status)) {
			return status;
		}
	} else {
		/*
		 * bso#12144: The underlying filesystem doesn't support
		 * compression, so we should respond with "not-compressed"
		 * (like WS2016 ReFS) instead of STATUS_NOT_SUPPORTED or
		 * NT_STATUS_INVALID_DEVICE_REQUEST.
		 */
		cmpr_state.format = COMPRESSION_FORMAT_NONE;
	}

	ndr_ret = ndr_push_struct_blob(&output, mem_ctx,
				       &cmpr_state,
			(ndr_push_flags_fn_t)ndr_push_compression_state);
	if (ndr_ret != NDR_ERR_SUCCESS) {
		return NT_STATUS_INTERNAL_ERROR;
	}

	if (in_max_output < output.length) {
		DEBUG(1, ("max output %u too small for compression state %ld\n",
		      (unsigned int)in_max_output, (long int)output.length));
		return NT_STATUS_INVALID_USER_BUFFER;
	}
	*out_output = output;

	return NT_STATUS_OK;
}

static NTSTATUS fsctl_set_cmprn(TALLOC_CTX *mem_ctx,
				struct tevent_context *ev,
				struct files_struct *fsp,
				DATA_BLOB *in_input)
{
	struct compression_state cmpr_state;
	enum ndr_err_code ndr_ret;
	NTSTATUS status;

	if (fsp == NULL) {
		return NT_STATUS_FILE_CLOSED;
	}

	/* WRITE_DATA permission is required, WRITE_ATTRIBUTES is not */
	status = check_access_fsp(fsp, FILE_WRITE_DATA);
	if (!NT_STATUS_IS_OK(status)) {
		return status;
	}

	ndr_ret = ndr_pull_struct_blob(in_input, mem_ctx, &cmpr_state,
			(ndr_pull_flags_fn_t)ndr_pull_compression_state);
	if (ndr_ret != NDR_ERR_SUCCESS) {
		DEBUG(0, ("failed to unmarshall set compression req\n"));
		return NT_STATUS_INVALID_PARAMETER;
	}

	status = NT_STATUS_NOT_SUPPORTED;
	if (fsp->conn->fs_capabilities & FILE_FILE_COMPRESSION) {
		status = SMB_VFS_SET_COMPRESSION(fsp->conn,
						 mem_ctx,
						 fsp,
						 cmpr_state.format);
	} else if (cmpr_state.format == COMPRESSION_FORMAT_NONE) {
		/*
		 * bso#12144: The underlying filesystem doesn't support
		 * compression. We should still accept set(FORMAT_NONE) requests
		 * (like WS2016 ReFS).
		 */
		status = NT_STATUS_OK;
	}

	return status;
}

static NTSTATUS fsctl_zero_data(TALLOC_CTX *mem_ctx,
				struct tevent_context *ev,
				struct files_struct *fsp,
				DATA_BLOB *in_input)
{
	struct file_zero_data_info zdata_info;
	enum ndr_err_code ndr_ret;
	struct lock_struct lck;
	int mode;
	uint64_t len;
	int ret;
	NTSTATUS status;

	if (fsp == NULL) {
		return NT_STATUS_FILE_CLOSED;
	}

	/* WRITE_DATA permission is required */
	status = check_access_fsp(fsp, FILE_WRITE_DATA);
	if (!NT_STATUS_IS_OK(status)) {
		return status;
	}

	/* allow regardless of whether FS supports sparse or not */

	ndr_ret = ndr_pull_struct_blob(in_input, mem_ctx, &zdata_info,
			(ndr_pull_flags_fn_t)ndr_pull_file_zero_data_info);
	if (ndr_ret != NDR_ERR_SUCCESS) {
		DEBUG(0, ("failed to unmarshall zero data request\n"));
		return NT_STATUS_INVALID_PARAMETER;
	}

	if (zdata_info.beyond_final_zero < zdata_info.file_off) {
		DEBUG(0, ("invalid zero data params: off %lu, bfz, %lu\n",
			  (unsigned long)zdata_info.file_off,
			  (unsigned long)zdata_info.beyond_final_zero));
		return NT_STATUS_INVALID_PARAMETER;
	}

	/* convert strange "beyond final zero" param into length */
	len = zdata_info.beyond_final_zero - zdata_info.file_off;

	if (len == 0) {
		DEBUG(2, ("zero data called with zero length range\n"));
		return NT_STATUS_OK;
	}

	init_strict_lock_struct(fsp,
				fsp->op->global->open_persistent_id,
				zdata_info.file_off,
				len,
				WRITE_LOCK,
				&lck);

	if (!SMB_VFS_STRICT_LOCK_CHECK(fsp->conn, fsp, &lck)) {
		DEBUG(2, ("failed to lock range for zero-data\n"));
		return NT_STATUS_FILE_LOCK_CONFLICT;
	}

	/*
	 * MS-FSCC <58> Section 2.3.67
	 * This FSCTL sets the range of bytes to zero (0) without extending the
	 * file size.
	 *
	 * The VFS_FALLOCATE_FL_KEEP_SIZE flag is used to satisfy this
	 * constraint.
	 */

	mode = VFS_FALLOCATE_FL_PUNCH_HOLE | VFS_FALLOCATE_FL_KEEP_SIZE;
	ret = SMB_VFS_FALLOCATE(fsp, mode, zdata_info.file_off, len);
	if (ret == -1)  {
		status = map_nt_error_from_unix_common(errno);
		DEBUG(2, ("zero-data fallocate(0x%x) failed: %s\n", mode,
		      strerror(errno)));
		return status;
	}

	if (!fsp->is_sparse && lp_strict_allocate(SNUM(fsp->conn))) {
		/*
		 * File marked non-sparse and "strict allocate" is enabled -
		 * allocate the range that we just punched out.
		 * In future FALLOC_FL_ZERO_RANGE could be used exclusively for
		 * this, but it's currently only supported on XFS and ext4.
		 *
		 * The newly allocated range still won't be found by SEEK_DATA
		 * for QAR, but stat.st_blocks will reflect it.
		 */
		ret = SMB_VFS_FALLOCATE(fsp, VFS_FALLOCATE_FL_KEEP_SIZE,
					zdata_info.file_off, len);
		if (ret == -1)  {
			status = map_nt_error_from_unix_common(errno);
			DEBUG(0, ("fallocate failed: %s\n", strerror(errno)));
			return status;
		}
	}

	return NT_STATUS_OK;
}

static NTSTATUS fsctl_qar_buf_push(TALLOC_CTX *mem_ctx,
				   struct file_alloced_range_buf *qar_buf,
				   DATA_BLOB *qar_array_blob)
{
	DATA_BLOB new_slot;
	enum ndr_err_code ndr_ret;
	bool ok;

	ndr_ret = ndr_push_struct_blob(&new_slot, mem_ctx, qar_buf,
			(ndr_push_flags_fn_t)ndr_push_file_alloced_range_buf);
	if (ndr_ret != NDR_ERR_SUCCESS) {
		DEBUG(0, ("failed to marshall QAR buf\n"));
		return NT_STATUS_INVALID_PARAMETER;
	}

	/* TODO should be able to avoid copy by pushing into prealloced buf */
	ok = data_blob_append(mem_ctx, qar_array_blob, new_slot.data,
			      new_slot.length);
	data_blob_free(&new_slot);
	if (!ok) {
		return NT_STATUS_NO_MEMORY;
	}

	return NT_STATUS_OK;
}

static NTSTATUS fsctl_qar_seek_fill(TALLOC_CTX *mem_ctx,
				    struct files_struct *fsp,
				    off_t curr_off,
				    off_t max_off,
				    DATA_BLOB *qar_array_blob)
{
	NTSTATUS status = NT_STATUS_NOT_SUPPORTED;

#ifdef HAVE_LSEEK_HOLE_DATA
	while (curr_off <= max_off) {
		off_t data_off;
		off_t hole_off;
		struct file_alloced_range_buf qar_buf;

		/* seek next data */
		data_off = SMB_VFS_LSEEK(fsp, curr_off, SEEK_DATA);
		if ((data_off == -1) && (errno == ENXIO)) {
			/* no data from curr_off to EOF */
			break;
		} else if (data_off == -1) {
			status = map_nt_error_from_unix_common(errno);
			DEBUG(1, ("lseek data failed: %s\n", strerror(errno)));
			return status;
		}

		if (data_off > max_off) {
			/* found something, but passed range of interest */
			break;
		}

		hole_off = SMB_VFS_LSEEK(fsp, data_off, SEEK_HOLE);
		if (hole_off == -1) {
			status = map_nt_error_from_unix_common(errno);
			DEBUG(1, ("lseek hole failed: %s\n", strerror(errno)));
			return status;
		}

		if (hole_off <= data_off) {
			DEBUG(1, ("lseek inconsistent: hole %lu at or before "
				  "data %lu\n", (unsigned long)hole_off,
				  (unsigned long)data_off));
			return NT_STATUS_INTERNAL_ERROR;
		}

		qar_buf.file_off = data_off;
		/* + 1 to convert maximum offset to length */
		qar_buf.len = MIN(hole_off, max_off + 1) - data_off;

		status = fsctl_qar_buf_push(mem_ctx, &qar_buf, qar_array_blob);
		if (!NT_STATUS_IS_OK(status)) {
			return NT_STATUS_NO_MEMORY;
		}

		curr_off = hole_off;
	}
	status = NT_STATUS_OK;
#endif

	return status;
}

static NTSTATUS fsctl_qar(TALLOC_CTX *mem_ctx,
			  struct tevent_context *ev,
			  struct files_struct *fsp,
			  DATA_BLOB *in_input,
			  size_t in_max_output,
			  DATA_BLOB *out_output)
{
	struct fsctl_query_alloced_ranges_req qar_req;
	struct fsctl_query_alloced_ranges_rsp qar_rsp;
	DATA_BLOB qar_array_blob = data_blob_null;
	uint64_t max_off;
	enum ndr_err_code ndr_ret;
	int ret;
	NTSTATUS status;
	SMB_STRUCT_STAT sbuf;

	if (fsp == NULL) {
		return NT_STATUS_FILE_CLOSED;
	}

	/* READ_DATA permission is required */
	status = check_access_fsp(fsp, FILE_READ_DATA);
	if (!NT_STATUS_IS_OK(status)) {
		return status;
	}

	ndr_ret = ndr_pull_struct_blob(in_input, mem_ctx, &qar_req,
		(ndr_pull_flags_fn_t)ndr_pull_fsctl_query_alloced_ranges_req);
	if (ndr_ret != NDR_ERR_SUCCESS) {
		DEBUG(0, ("failed to unmarshall QAR req\n"));
		return NT_STATUS_INVALID_PARAMETER;
	}

	/*
	 * XXX Windows Server 2008 & 2012 servers don't return lock-conflict
	 * for QAR requests over an exclusively locked range!
	 */

	ret = SMB_VFS_FSTAT(fsp, &sbuf);
	if (ret == -1) {
		status = map_nt_error_from_unix_common(errno);
		DEBUG(2, ("fstat failed: %s\n", strerror(errno)));
		return status;
	}

	if ((qar_req.buf.len == 0)
	 || (sbuf.st_ex_size == 0)
	 || (qar_req.buf.file_off >= sbuf.st_ex_size)) {
		/* zero length range or after EOF, no ranges to return */
		return NT_STATUS_OK;
	}

	/* check for integer overflow */
	if (qar_req.buf.file_off + qar_req.buf.len < qar_req.buf.file_off) {
		return NT_STATUS_INVALID_PARAMETER;
	}

	/*
	 * Maximum offset is either the last valid offset _before_ EOF, or the
	 * last byte offset within the requested range. -1 converts length to
	 * offset, which is easier to work with for SEEK_DATA/SEEK_HOLE, E.g.:
	 *
	 * /off=0             /off=512K          /st_ex_size=1M
	 * |-------------------------------------|
	 * | File data                           |
	 * |-------------------------------------|
	 *                                                   QAR end\
	 *                    |=====================================|
	 *                    |    QAR off=512K, len=1M             |
	 *                    |=================^===================|
	 *                                   max_off=1M - 1
	 *             QAR end\
	 * |==================|
	 * |QAR off=0 len=512K|
	 * |==================|
	 *                   ^
	 *                max_off=512K - 1
	 */
	max_off = MIN(sbuf.st_ex_size,
		      qar_req.buf.file_off + qar_req.buf.len) - 1;

	if (!fsp->is_sparse) {
		struct file_alloced_range_buf qar_buf;

		/* file is non-sparse, claim file_off->max_off is allocated */
		qar_buf.file_off = qar_req.buf.file_off;
		/* + 1 to convert maximum offset back to length */
		qar_buf.len = max_off - qar_req.buf.file_off + 1;

		status = fsctl_qar_buf_push(mem_ctx, &qar_buf, &qar_array_blob);
	} else {
		status = fsctl_qar_seek_fill(mem_ctx, fsp, qar_req.buf.file_off,
					     max_off, &qar_array_blob);
	}
	if (!NT_STATUS_IS_OK(status)) {
		return status;
	}

	/* marshall response buffer. */
	qar_rsp.far_buf_array = qar_array_blob;

	ndr_ret = ndr_push_struct_blob(out_output, mem_ctx, &qar_rsp,
		(ndr_push_flags_fn_t)ndr_push_fsctl_query_alloced_ranges_rsp);
	if (ndr_ret != NDR_ERR_SUCCESS) {
		DEBUG(0, ("failed to marshall QAR rsp\n"));
		return NT_STATUS_INVALID_PARAMETER;
	}

	if (out_output->length > in_max_output) {
		DEBUG(2, ("QAR output len %lu exceeds max %lu\n",
			  (unsigned long)out_output->length,
			  (unsigned long)in_max_output));
		data_blob_free(out_output);
		return NT_STATUS_BUFFER_TOO_SMALL;
	}

	return NT_STATUS_OK;
}

static void smb2_ioctl_filesys_dup_extents_done(struct tevent_req *subreq);

struct tevent_req *smb2_ioctl_filesys(uint32_t ctl_code,
				      struct tevent_context *ev,
				      struct tevent_req *req,
				      struct smbd_smb2_ioctl_state *state)
{
	NTSTATUS status;

	switch (ctl_code) {
	case FSCTL_GET_COMPRESSION:
		status = fsctl_get_cmprn(state, ev, state->fsp,
					 state->in_max_output,
					 &state->out_output);
		if (!tevent_req_nterror(req, status)) {
			tevent_req_done(req);
		}
		return tevent_req_post(req, ev);
		break;
	case FSCTL_SET_COMPRESSION:
		status = fsctl_set_cmprn(state, ev, state->fsp,
					 &state->in_input);
		if (!tevent_req_nterror(req, status)) {
			tevent_req_done(req);
		}
		return tevent_req_post(req, ev);
		break;
	case FSCTL_SET_ZERO_DATA:
		status = fsctl_zero_data(state, ev, state->fsp,
					 &state->in_input);
		if (!tevent_req_nterror(req, status)) {
			tevent_req_done(req);
		}
		return tevent_req_post(req, ev);
		break;
	case FSCTL_QUERY_ALLOCATED_RANGES:
		status = fsctl_qar(state, ev, state->fsp,
				   &state->in_input,
				   state->in_max_output,
				   &state->out_output);
		if (!tevent_req_nterror(req, status)) {
			tevent_req_done(req);
		}
		return tevent_req_post(req, ev);
		break;
	case FSCTL_DUP_EXTENTS_TO_FILE: {
		struct tevent_req *subreq = NULL;

		subreq = fsctl_dup_extents_send(state, ev,
						state->fsp,
						&state->in_input,
						state->smb2req);
		if (tevent_req_nomem(subreq, req)) {
			return tevent_req_post(req, ev);
		}
		tevent_req_set_callback(subreq,
					smb2_ioctl_filesys_dup_extents_done,
					req);
		return req;
		break;
	}
	default: {
		uint8_t *out_data = NULL;
		uint32_t out_data_len = 0;

		if (state->fsp == NULL) {
			status = NT_STATUS_NOT_SUPPORTED;
		} else {
			status = SMB_VFS_FSCTL(state->fsp,
					       state,
					       ctl_code,
					       state->smbreq->flags2,
					       state->in_input.data,
					       state->in_input.length,
					       &out_data,
					       state->in_max_output,
					       &out_data_len);
			state->out_output = data_blob_const(out_data, out_data_len);
			if (NT_STATUS_IS_OK(status)) {
				tevent_req_done(req);
				return tevent_req_post(req, ev);
			}
		}

		if (NT_STATUS_EQUAL(status, NT_STATUS_NOT_SUPPORTED)) {
			if (IS_IPC(state->smbreq->conn)) {
				status = NT_STATUS_FS_DRIVER_REQUIRED;
			} else {
				status = NT_STATUS_INVALID_DEVICE_REQUEST;
			}
		}

		tevent_req_nterror(req, status);
		return tevent_req_post(req, ev);
		break;
	}
	}

	tevent_req_nterror(req, NT_STATUS_INTERNAL_ERROR);
	return tevent_req_post(req, ev);
}

static void smb2_ioctl_filesys_dup_extents_done(struct tevent_req *subreq)
{
	struct tevent_req *req = tevent_req_callback_data(subreq,
							  struct tevent_req);
	NTSTATUS status;

	status = fsctl_dup_extents_recv(subreq);
	TALLOC_FREE(subreq);
	if (!tevent_req_nterror(req, status)) {
		tevent_req_done(req);
	}
}