fs/smb/client/smb2file.c - linux - Git at Google

 // SPDX-License-Identifier: LGPL-2.1
 /*
  *
  *   Copyright (C) International Business Machines  Corp., 2002, 2011
  *   Author(s): Steve French (sfrench@us.ibm.com),
  *              Pavel Shilovsky ((pshilovsky@samba.org) 2012
  *
  */
 #include <linux/fs.h>
 #include <linux/filelock.h>
 #include <linux/stat.h>
 #include <linux/slab.h>
 #include <linux/pagemap.h>
 #include <asm/div64.h>
 #include "cifsfs.h"
 #include "cifspdu.h"
 #include "cifsglob.h"
 #include "cifsproto.h"
 #include "cifs_debug.h"
 #include "cifs_fs_sb.h"
 #include "cifs_unicode.h"
 #include "fscache.h"
 #include "smb2proto.h"
 #include "smb2status.h"

 static struct smb2_symlink_err_rsp *symlink_data(const struct kvec *iov)
 {
 	struct smb2_err_rsp *err = iov->iov_base;
 	struct smb2_symlink_err_rsp *sym = ERR_PTR(-EINVAL);
 	u32 len;

 	if (err->ErrorContextCount) {
 		struct smb2_error_context_rsp *p, *end;

 		len = (u32)err->ErrorContextCount * (offsetof(struct smb2_error_context_rsp,
 							      ErrorContextData) +
 						     sizeof(struct smb2_symlink_err_rsp));
 		if (le32_to_cpu(err->ByteCount) < len || iov->iov_len < len + sizeof(*err) + 1)
 			return ERR_PTR(-EINVAL);

 		p = (struct smb2_error_context_rsp *)err->ErrorData;
 		end = (struct smb2_error_context_rsp *)((u8 *)err + iov->iov_len);
 		do {
 			if (le32_to_cpu(p->ErrorId) == SMB2_ERROR_ID_DEFAULT) {
 				sym = (struct smb2_symlink_err_rsp *)&p->ErrorContextData;
 				break;
 			}
 			cifs_dbg(FYI, "%s: skipping unhandled error context: 0x%x\n",
 				 __func__, le32_to_cpu(p->ErrorId));

 			len = ALIGN(le32_to_cpu(p->ErrorDataLength), 8);
 			p = (struct smb2_error_context_rsp *)((u8 *)&p->ErrorContextData + len);
 		} while (p < end);
 	} else if (le32_to_cpu(err->ByteCount) >= sizeof(*sym) &&
 		   iov->iov_len >= SMB2_SYMLINK_STRUCT_SIZE) {
 		sym = (struct smb2_symlink_err_rsp *)err->ErrorData;
 	}

 	if (!IS_ERR(sym) && (le32_to_cpu(sym->SymLinkErrorTag) != SYMLINK_ERROR_TAG ||
 			     le32_to_cpu(sym->ReparseTag) != IO_REPARSE_TAG_SYMLINK))
 		sym = ERR_PTR(-EINVAL);

 	return sym;
 }

 int smb2_parse_symlink_response(struct cifs_sb_info *cifs_sb, const struct kvec *iov, char **path)
 {
 	struct smb2_symlink_err_rsp *sym;
 	unsigned int sub_offs, sub_len;
 	unsigned int print_offs, print_len;
 	char *s;

 	if (!cifs_sb || !iov || !iov->iov_base || !iov->iov_len || !path)
 		return -EINVAL;

 	sym = symlink_data(iov);
 	if (IS_ERR(sym))
 		return PTR_ERR(sym);

 	sub_len = le16_to_cpu(sym->SubstituteNameLength);
 	sub_offs = le16_to_cpu(sym->SubstituteNameOffset);
 	print_len = le16_to_cpu(sym->PrintNameLength);
 	print_offs = le16_to_cpu(sym->PrintNameOffset);

 	if (iov->iov_len < SMB2_SYMLINK_STRUCT_SIZE + sub_offs + sub_len ||
 	    iov->iov_len < SMB2_SYMLINK_STRUCT_SIZE + print_offs + print_len)
 		return -EINVAL;

 	s = cifs_strndup_from_utf16((char *)sym->PathBuffer + sub_offs, sub_len, true,
 				    cifs_sb->local_nls);
 	if (!s)
 		return -ENOMEM;
 	convert_delimiter(s, '/');
 	cifs_dbg(FYI, "%s: symlink target: %s\n", __func__, s);

 	*path = s;
 	return 0;
 }

 int smb2_open_file(const unsigned int xid, struct cifs_open_parms *oparms, __u32 *oplock, void *buf)
 {
 	int rc;
 	__le16 *smb2_path;
 	__u8 smb2_oplock;
 	struct cifs_open_info_data *data = buf;
 	struct smb2_file_all_info file_info = {};
 	struct smb2_file_all_info *smb2_data = data ? &file_info : NULL;
 	struct kvec err_iov = {};
 	int err_buftype = CIFS_NO_BUFFER;
 	struct cifs_fid *fid = oparms->fid;
 	struct network_resiliency_req nr_ioctl_req;

 	smb2_path = cifs_convert_path_to_utf16(oparms->path, oparms->cifs_sb);
 	if (smb2_path == NULL)
 		return -ENOMEM;

 	oparms->desired_access |= FILE_READ_ATTRIBUTES;
 	smb2_oplock = SMB2_OPLOCK_LEVEL_BATCH;

 	rc = SMB2_open(xid, oparms, smb2_path, &smb2_oplock, smb2_data, NULL, &err_iov,
 		       &err_buftype);
 	if (rc && data) {
 		struct smb2_hdr *hdr = err_iov.iov_base;

 		if (unlikely(!err_iov.iov_base || err_buftype == CIFS_NO_BUFFER))
 			goto out;
 		if (hdr->Status == STATUS_STOPPED_ON_SYMLINK) {
 			rc = smb2_parse_symlink_response(oparms->cifs_sb, &err_iov,
 							 &data->symlink_target);
 			if (!rc) {
 				memset(smb2_data, 0, sizeof(*smb2_data));
 				oparms->create_options |= OPEN_REPARSE_POINT;
 				rc = SMB2_open(xid, oparms, smb2_path, &smb2_oplock, smb2_data,
 					       NULL, NULL, NULL);
 				oparms->create_options &= ~OPEN_REPARSE_POINT;
 			}
 		}
 	}

 	if (rc)
 		goto out;

 	if (oparms->tcon->use_resilient) {
 		/* default timeout is 0, servers pick default (120 seconds) */
 		nr_ioctl_req.Timeout =
 			cpu_to_le32(oparms->tcon->handle_timeout);
 		nr_ioctl_req.Reserved = 0;
 		rc = SMB2_ioctl(xid, oparms->tcon, fid->persistent_fid,
 			fid->volatile_fid, FSCTL_LMR_REQUEST_RESILIENCY,
 			(char *)&nr_ioctl_req, sizeof(nr_ioctl_req),
 			CIFSMaxBufSize, NULL, NULL /* no return info */);
 		if (rc == -EOPNOTSUPP) {
 			cifs_dbg(VFS,
 			     "resiliency not supported by server, disabling\n");
 			oparms->tcon->use_resilient = false;
 		} else if (rc)
 			cifs_dbg(FYI, "error %d setting resiliency\n", rc);

 		rc = 0;
 	}

 	if (smb2_data) {
 		/* if open response does not have IndexNumber field - get it */
 		if (smb2_data->IndexNumber == 0) {
 			rc = SMB2_get_srv_num(xid, oparms->tcon,
 				      fid->persistent_fid,
 				      fid->volatile_fid,
 				      &smb2_data->IndexNumber);
 			if (rc) {
 				/*
 				 * let get_inode_info disable server inode
 				 * numbers
 				 */
 				smb2_data->IndexNumber = 0;
 				rc = 0;
 			}
 		}
 		memcpy(&data->fi, smb2_data, sizeof(data->fi));
 	}

 	*oplock = smb2_oplock;
 out:
 	free_rsp_buf(err_buftype, err_iov.iov_base);
 	kfree(smb2_path);
 	return rc;
 }

 int
 smb2_unlock_range(struct cifsFileInfo *cfile, struct file_lock *flock,
 		  const unsigned int xid)
 {
 	int rc = 0, stored_rc;
 	unsigned int max_num, num = 0, max_buf;
 	struct smb2_lock_element *buf, *cur;
 	struct cifs_tcon *tcon = tlink_tcon(cfile->tlink);
 	struct cifsInodeInfo *cinode = CIFS_I(d_inode(cfile->dentry));
 	struct cifsLockInfo *li, *tmp;
 	__u64 length = 1 + flock->fl_end - flock->fl_start;
 	struct list_head tmp_llist;

 	INIT_LIST_HEAD(&tmp_llist);

 	/*
 	 * Accessing maxBuf is racy with cifs_reconnect - need to store value
 	 * and check it before using.
 	 */
 	max_buf = tcon->ses->server->maxBuf;
 	if (max_buf < sizeof(struct smb2_lock_element))
 		return -EINVAL;

 	BUILD_BUG_ON(sizeof(struct smb2_lock_element) > PAGE_SIZE);
 	max_buf = min_t(unsigned int, max_buf, PAGE_SIZE);
 	max_num = max_buf / sizeof(struct smb2_lock_element);
 	buf = kcalloc(max_num, sizeof(struct smb2_lock_element), GFP_KERNEL);
 	if (!buf)
 		return -ENOMEM;

 	cur = buf;

 	cifs_down_write(&cinode->lock_sem);
 	list_for_each_entry_safe(li, tmp, &cfile->llist->locks, llist) {
 		if (flock->fl_start > li->offset ||
 		    (flock->fl_start + length) <
 		    (li->offset + li->length))
 			continue;
 		if (current->tgid != li->pid)
 			/*
 			 * flock and OFD lock are associated with an open
 			 * file description, not the process.
 			 */
 			if (!(flock->fl_flags & (FL_FLOCK | FL_OFDLCK)))
 				continue;
 		if (cinode->can_cache_brlcks) {
 			/*
 			 * We can cache brlock requests - simply remove a lock
 			 * from the file's list.
 			 */
 			list_del(&li->llist);
 			cifs_del_lock_waiters(li);
 			kfree(li);
 			continue;
 		}
 		cur->Length = cpu_to_le64(li->length);
 		cur->Offset = cpu_to_le64(li->offset);
 		cur->Flags = cpu_to_le32(SMB2_LOCKFLAG_UNLOCK);
 		/*
 		 * We need to save a lock here to let us add it again to the
 		 * file's list if the unlock range request fails on the server.
 		 */
 		list_move(&li->llist, &tmp_llist);
 		if (++num == max_num) {
 			stored_rc = smb2_lockv(xid, tcon,
 					       cfile->fid.persistent_fid,
 					       cfile->fid.volatile_fid,
 					       current->tgid, num, buf);
 			if (stored_rc) {
 				/*
 				 * We failed on the unlock range request - add
 				 * all locks from the tmp list to the head of
 				 * the file's list.
 				 */
 				cifs_move_llist(&tmp_llist,
 						&cfile->llist->locks);
 				rc = stored_rc;
 			} else
 				/*
 				 * The unlock range request succeed - free the
 				 * tmp list.
 				 */
 				cifs_free_llist(&tmp_llist);
 			cur = buf;
 			num = 0;
 		} else
 			cur++;
 	}
 	if (num) {
 		stored_rc = smb2_lockv(xid, tcon, cfile->fid.persistent_fid,
 				       cfile->fid.volatile_fid, current->tgid,
 				       num, buf);
 		if (stored_rc) {
 			cifs_move_llist(&tmp_llist, &cfile->llist->locks);
 			rc = stored_rc;
 		} else
 			cifs_free_llist(&tmp_llist);
 	}
 	up_write(&cinode->lock_sem);

 	kfree(buf);
 	return rc;
 }

 static int
 smb2_push_mand_fdlocks(struct cifs_fid_locks *fdlocks, const unsigned int xid,
 		       struct smb2_lock_element *buf, unsigned int max_num)
 {
 	int rc = 0, stored_rc;
 	struct cifsFileInfo *cfile = fdlocks->cfile;
 	struct cifsLockInfo *li;
 	unsigned int num = 0;
 	struct smb2_lock_element *cur = buf;
 	struct cifs_tcon *tcon = tlink_tcon(cfile->tlink);

 	list_for_each_entry(li, &fdlocks->locks, llist) {
 		cur->Length = cpu_to_le64(li->length);
 		cur->Offset = cpu_to_le64(li->offset);
 		cur->Flags = cpu_to_le32(li->type |
 						SMB2_LOCKFLAG_FAIL_IMMEDIATELY);
 		if (++num == max_num) {
 			stored_rc = smb2_lockv(xid, tcon,
 					       cfile->fid.persistent_fid,
 					       cfile->fid.volatile_fid,
 					       current->tgid, num, buf);
 			if (stored_rc)
 				rc = stored_rc;
 			cur = buf;
 			num = 0;
 		} else
 			cur++;
 	}
 	if (num) {
 		stored_rc = smb2_lockv(xid, tcon,
 				       cfile->fid.persistent_fid,
 				       cfile->fid.volatile_fid,
 				       current->tgid, num, buf);
 		if (stored_rc)
 			rc = stored_rc;
 	}

 	return rc;
 }

 int
 smb2_push_mandatory_locks(struct cifsFileInfo *cfile)
 {
 	int rc = 0, stored_rc;
 	unsigned int xid;
 	unsigned int max_num, max_buf;
 	struct smb2_lock_element *buf;
 	struct cifsInodeInfo *cinode = CIFS_I(d_inode(cfile->dentry));
 	struct cifs_fid_locks *fdlocks;

 	xid = get_xid();

 	/*
 	 * Accessing maxBuf is racy with cifs_reconnect - need to store value
 	 * and check it for zero before using.
 	 */
 	max_buf = tlink_tcon(cfile->tlink)->ses->server->maxBuf;
 	if (max_buf < sizeof(struct smb2_lock_element)) {
 		free_xid(xid);
 		return -EINVAL;
 	}

 	BUILD_BUG_ON(sizeof(struct smb2_lock_element) > PAGE_SIZE);
 	max_buf = min_t(unsigned int, max_buf, PAGE_SIZE);
 	max_num = max_buf / sizeof(struct smb2_lock_element);
 	buf = kcalloc(max_num, sizeof(struct smb2_lock_element), GFP_KERNEL);
 	if (!buf) {
 		free_xid(xid);
 		return -ENOMEM;
 	}

 	list_for_each_entry(fdlocks, &cinode->llist, llist) {
 		stored_rc = smb2_push_mand_fdlocks(fdlocks, xid, buf, max_num);
 		if (stored_rc)
 			rc = stored_rc;
 	}

 	kfree(buf);
 	free_xid(xid);
 	return rc;
 }
	// SPDX-License-Identifier: LGPL-2.1
	/*
	*
	* Copyright (C) International Business Machines Corp., 2002, 2011
	* Author(s): Steve French (sfrench@us.ibm.com),
	* Pavel Shilovsky ((pshilovsky@samba.org) 2012
	*
	*/
	#include <linux/fs.h>
	#include <linux/filelock.h>
	#include <linux/stat.h>
	#include <linux/slab.h>
	#include <linux/pagemap.h>
	#include <asm/div64.h>
	#include "cifsfs.h"
	#include "cifspdu.h"
	#include "cifsglob.h"
	#include "cifsproto.h"
	#include "cifs_debug.h"
	#include "cifs_fs_sb.h"
	#include "cifs_unicode.h"
	#include "fscache.h"
	#include "smb2proto.h"
	#include "smb2status.h"

	static struct smb2_symlink_err_rsp symlink_data(const struct kvec iov)
	{
	struct smb2_err_rsp *err = iov->iov_base;
	struct smb2_symlink_err_rsp *sym = ERR_PTR(-EINVAL);
	u32 len;

	if (err->ErrorContextCount) {
	struct smb2_error_context_rsp p, end;

	len = (u32)err->ErrorContextCount * (offsetof(struct smb2_error_context_rsp,
	ErrorContextData) +
	sizeof(struct smb2_symlink_err_rsp));
	if (le32_to_cpu(err->ByteCount) < len \|\| iov->iov_len < len + sizeof(*err) + 1)
	return ERR_PTR(-EINVAL);

	p = (struct smb2_error_context_rsp *)err->ErrorData;
	end = (struct smb2_error_context_rsp )((u8 )err + iov->iov_len);
	do {
	if (le32_to_cpu(p->ErrorId) == SMB2_ERROR_ID_DEFAULT) {
	sym = (struct smb2_symlink_err_rsp *)&p->ErrorContextData;
	break;
	}
	cifs_dbg(FYI, "%s: skipping unhandled error context: 0x%x\n",
	__func__, le32_to_cpu(p->ErrorId));

	len = ALIGN(le32_to_cpu(p->ErrorDataLength), 8);
	p = (struct smb2_error_context_rsp )((u8 )&p->ErrorContextData + len);
	} while (p < end);
	} else if (le32_to_cpu(err->ByteCount) >= sizeof(*sym) &&
	iov->iov_len >= SMB2_SYMLINK_STRUCT_SIZE) {
	sym = (struct smb2_symlink_err_rsp *)err->ErrorData;
	}

	if (!IS_ERR(sym) && (le32_to_cpu(sym->SymLinkErrorTag) != SYMLINK_ERROR_TAG \|\|
	le32_to_cpu(sym->ReparseTag) != IO_REPARSE_TAG_SYMLINK))
	sym = ERR_PTR(-EINVAL);

	return sym;
	}

	int smb2_parse_symlink_response(struct cifs_sb_info cifs_sb, const struct kvec iov, char **path)
	{
	struct smb2_symlink_err_rsp *sym;
	unsigned int sub_offs, sub_len;
	unsigned int print_offs, print_len;
	char *s;

	if (!cifs_sb \|\| !iov \|\| !iov->iov_base \|\| !iov->iov_len \|\| !path)
	return -EINVAL;

	sym = symlink_data(iov);
	if (IS_ERR(sym))
	return PTR_ERR(sym);

	sub_len = le16_to_cpu(sym->SubstituteNameLength);
	sub_offs = le16_to_cpu(sym->SubstituteNameOffset);
	print_len = le16_to_cpu(sym->PrintNameLength);
	print_offs = le16_to_cpu(sym->PrintNameOffset);

	if (iov->iov_len < SMB2_SYMLINK_STRUCT_SIZE + sub_offs + sub_len \|\|
	iov->iov_len < SMB2_SYMLINK_STRUCT_SIZE + print_offs + print_len)
	return -EINVAL;

	s = cifs_strndup_from_utf16((char *)sym->PathBuffer + sub_offs, sub_len, true,
	cifs_sb->local_nls);
	if (!s)
	return -ENOMEM;
	convert_delimiter(s, '/');
	cifs_dbg(FYI, "%s: symlink target: %s\n", __func__, s);

	*path = s;
	return 0;
	}

	int smb2_open_file(const unsigned int xid, struct cifs_open_parms oparms, __u32 oplock, void *buf)
	{
	int rc;
	__le16 *smb2_path;
	__u8 smb2_oplock;
	struct cifs_open_info_data *data = buf;
	struct smb2_file_all_info file_info = {};
	struct smb2_file_all_info *smb2_data = data ? &file_info : NULL;
	struct kvec err_iov = {};
	int err_buftype = CIFS_NO_BUFFER;
	struct cifs_fid *fid = oparms->fid;
	struct network_resiliency_req nr_ioctl_req;

	smb2_path = cifs_convert_path_to_utf16(oparms->path, oparms->cifs_sb);
	if (smb2_path == NULL)
	return -ENOMEM;

	oparms->desired_access \|= FILE_READ_ATTRIBUTES;
	smb2_oplock = SMB2_OPLOCK_LEVEL_BATCH;

	rc = SMB2_open(xid, oparms, smb2_path, &smb2_oplock, smb2_data, NULL, &err_iov,
	&err_buftype);
	if (rc && data) {
	struct smb2_hdr *hdr = err_iov.iov_base;

	if (unlikely(!err_iov.iov_base \|\| err_buftype == CIFS_NO_BUFFER))
	goto out;
	if (hdr->Status == STATUS_STOPPED_ON_SYMLINK) {
	rc = smb2_parse_symlink_response(oparms->cifs_sb, &err_iov,
	&data->symlink_target);
	if (!rc) {
	memset(smb2_data, 0, sizeof(*smb2_data));
	oparms->create_options \|= OPEN_REPARSE_POINT;
	rc = SMB2_open(xid, oparms, smb2_path, &smb2_oplock, smb2_data,
	NULL, NULL, NULL);
	oparms->create_options &= ~OPEN_REPARSE_POINT;
	}
	}
	}

	if (rc)
	goto out;

	if (oparms->tcon->use_resilient) {
	/* default timeout is 0, servers pick default (120 seconds) */
	nr_ioctl_req.Timeout =
	cpu_to_le32(oparms->tcon->handle_timeout);
	nr_ioctl_req.Reserved = 0;
	rc = SMB2_ioctl(xid, oparms->tcon, fid->persistent_fid,
	fid->volatile_fid, FSCTL_LMR_REQUEST_RESILIENCY,
	(char *)&nr_ioctl_req, sizeof(nr_ioctl_req),
	CIFSMaxBufSize, NULL, NULL /* no return info */);
	if (rc == -EOPNOTSUPP) {
	cifs_dbg(VFS,
	"resiliency not supported by server, disabling\n");
	oparms->tcon->use_resilient = false;
	} else if (rc)
	cifs_dbg(FYI, "error %d setting resiliency\n", rc);

	rc = 0;
	}

	if (smb2_data) {
	/* if open response does not have IndexNumber field - get it */
	if (smb2_data->IndexNumber == 0) {
	rc = SMB2_get_srv_num(xid, oparms->tcon,
	fid->persistent_fid,
	fid->volatile_fid,
	&smb2_data->IndexNumber);
	if (rc) {
	/*
	* let get_inode_info disable server inode
	* numbers
	*/
	smb2_data->IndexNumber = 0;
	rc = 0;
	}
	}
	memcpy(&data->fi, smb2_data, sizeof(data->fi));
	}

	*oplock = smb2_oplock;
	out:
	free_rsp_buf(err_buftype, err_iov.iov_base);
	kfree(smb2_path);
	return rc;
	}

	int
	smb2_unlock_range(struct cifsFileInfo cfile, struct file_lock flock,
	const unsigned int xid)
	{
	int rc = 0, stored_rc;
	unsigned int max_num, num = 0, max_buf;
	struct smb2_lock_element buf, cur;
	struct cifs_tcon *tcon = tlink_tcon(cfile->tlink);
	struct cifsInodeInfo *cinode = CIFS_I(d_inode(cfile->dentry));
	struct cifsLockInfo li, tmp;
	__u64 length = 1 + flock->fl_end - flock->fl_start;
	struct list_head tmp_llist;

	INIT_LIST_HEAD(&tmp_llist);

	/*
	* Accessing maxBuf is racy with cifs_reconnect - need to store value
	* and check it before using.
	*/
	max_buf = tcon->ses->server->maxBuf;
	if (max_buf < sizeof(struct smb2_lock_element))
	return -EINVAL;

	BUILD_BUG_ON(sizeof(struct smb2_lock_element) > PAGE_SIZE);
	max_buf = min_t(unsigned int, max_buf, PAGE_SIZE);
	max_num = max_buf / sizeof(struct smb2_lock_element);
	buf = kcalloc(max_num, sizeof(struct smb2_lock_element), GFP_KERNEL);
	if (!buf)
	return -ENOMEM;

	cur = buf;

	cifs_down_write(&cinode->lock_sem);
	list_for_each_entry_safe(li, tmp, &cfile->llist->locks, llist) {
	if (flock->fl_start > li->offset \|\|
	(flock->fl_start + length) <
	(li->offset + li->length))
	continue;
	if (current->tgid != li->pid)
	/*
	* flock and OFD lock are associated with an open
	* file description, not the process.
	*/
	if (!(flock->fl_flags & (FL_FLOCK \| FL_OFDLCK)))
	continue;
	if (cinode->can_cache_brlcks) {
	/*
	* We can cache brlock requests - simply remove a lock
	* from the file's list.
	*/
	list_del(&li->llist);
	cifs_del_lock_waiters(li);
	kfree(li);
	continue;
	}
	cur->Length = cpu_to_le64(li->length);
	cur->Offset = cpu_to_le64(li->offset);
	cur->Flags = cpu_to_le32(SMB2_LOCKFLAG_UNLOCK);
	/*
	* We need to save a lock here to let us add it again to the
	* file's list if the unlock range request fails on the server.
	*/
	list_move(&li->llist, &tmp_llist);
	if (++num == max_num) {
	stored_rc = smb2_lockv(xid, tcon,
	cfile->fid.persistent_fid,
	cfile->fid.volatile_fid,
	current->tgid, num, buf);
	if (stored_rc) {
	/*
	* We failed on the unlock range request - add
	* all locks from the tmp list to the head of
	* the file's list.
	*/
	cifs_move_llist(&tmp_llist,
	&cfile->llist->locks);
	rc = stored_rc;
	} else
	/*
	* The unlock range request succeed - free the
	* tmp list.
	*/
	cifs_free_llist(&tmp_llist);
	cur = buf;
	num = 0;
	} else
	cur++;
	}
	if (num) {
	stored_rc = smb2_lockv(xid, tcon, cfile->fid.persistent_fid,
	cfile->fid.volatile_fid, current->tgid,
	num, buf);
	if (stored_rc) {
	cifs_move_llist(&tmp_llist, &cfile->llist->locks);
	rc = stored_rc;
	} else
	cifs_free_llist(&tmp_llist);
	}
	up_write(&cinode->lock_sem);

	kfree(buf);
	return rc;
	}

	static int
	smb2_push_mand_fdlocks(struct cifs_fid_locks *fdlocks, const unsigned int xid,
	struct smb2_lock_element *buf, unsigned int max_num)
	{
	int rc = 0, stored_rc;
	struct cifsFileInfo *cfile = fdlocks->cfile;
	struct cifsLockInfo *li;
	unsigned int num = 0;
	struct smb2_lock_element *cur = buf;
	struct cifs_tcon *tcon = tlink_tcon(cfile->tlink);

	list_for_each_entry(li, &fdlocks->locks, llist) {
	cur->Length = cpu_to_le64(li->length);
	cur->Offset = cpu_to_le64(li->offset);
	cur->Flags = cpu_to_le32(li->type \|
	SMB2_LOCKFLAG_FAIL_IMMEDIATELY);
	if (++num == max_num) {
	stored_rc = smb2_lockv(xid, tcon,
	cfile->fid.persistent_fid,
	cfile->fid.volatile_fid,
	current->tgid, num, buf);
	if (stored_rc)
	rc = stored_rc;
	cur = buf;
	num = 0;
	} else
	cur++;
	}
	if (num) {
	stored_rc = smb2_lockv(xid, tcon,
	cfile->fid.persistent_fid,
	cfile->fid.volatile_fid,
	current->tgid, num, buf);
	if (stored_rc)
	rc = stored_rc;
	}

	return rc;
	}

	int
	smb2_push_mandatory_locks(struct cifsFileInfo *cfile)
	{
	int rc = 0, stored_rc;
	unsigned int xid;
	unsigned int max_num, max_buf;
	struct smb2_lock_element *buf;
	struct cifsInodeInfo *cinode = CIFS_I(d_inode(cfile->dentry));
	struct cifs_fid_locks *fdlocks;

	xid = get_xid();

	/*
	* Accessing maxBuf is racy with cifs_reconnect - need to store value
	* and check it for zero before using.
	*/
	max_buf = tlink_tcon(cfile->tlink)->ses->server->maxBuf;
	if (max_buf < sizeof(struct smb2_lock_element)) {
	free_xid(xid);
	return -EINVAL;
	}

	BUILD_BUG_ON(sizeof(struct smb2_lock_element) > PAGE_SIZE);
	max_buf = min_t(unsigned int, max_buf, PAGE_SIZE);
	max_num = max_buf / sizeof(struct smb2_lock_element);
	buf = kcalloc(max_num, sizeof(struct smb2_lock_element), GFP_KERNEL);
	if (!buf) {
	free_xid(xid);
	return -ENOMEM;
	}

	list_for_each_entry(fdlocks, &cinode->llist, llist) {
	stored_rc = smb2_push_mand_fdlocks(fdlocks, xid, buf, max_num);
	if (stored_rc)
	rc = stored_rc;
	}

	kfree(buf);
	free_xid(xid);
	return rc;
	}