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![Ross Lagerwall](/assets/img/avatar_default.png)
The code tries to allocate a contiguous buffer with a size supplied by the server (maxBuf). This could fail if memory is fragmented since it results in high order allocations for commonly used server implementations. It is also wasteful since there are probably few locks in the usual case. Limit the buffer to be no larger than a page to avoid memory allocation failures due to fragmentation. Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com> Signed-off-by: Steve French <stfrench@microsoft.com>
287 lines
7.7 KiB
C
287 lines
7.7 KiB
C
/*
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* fs/cifs/smb2file.c
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*
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* Copyright (C) International Business Machines Corp., 2002, 2011
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* Author(s): Steve French (sfrench@us.ibm.com),
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* Pavel Shilovsky ((pshilovsky@samba.org) 2012
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*
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* This library is free software; you can redistribute it and/or modify
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* it under the terms of the GNU Lesser General Public License as published
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* by the Free Software Foundation; either version 2.1 of the License, or
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* (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
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* the GNU Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with this library; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#include <linux/fs.h>
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#include <linux/stat.h>
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#include <linux/slab.h>
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#include <linux/pagemap.h>
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#include <asm/div64.h>
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#include "cifsfs.h"
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#include "cifspdu.h"
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#include "cifsglob.h"
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#include "cifsproto.h"
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#include "cifs_debug.h"
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#include "cifs_fs_sb.h"
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#include "cifs_unicode.h"
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#include "fscache.h"
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#include "smb2proto.h"
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int
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smb2_open_file(const unsigned int xid, struct cifs_open_parms *oparms,
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__u32 *oplock, FILE_ALL_INFO *buf)
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{
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int rc;
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__le16 *smb2_path;
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struct smb2_file_all_info *smb2_data = NULL;
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__u8 smb2_oplock;
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struct cifs_fid *fid = oparms->fid;
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struct network_resiliency_req nr_ioctl_req;
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smb2_path = cifs_convert_path_to_utf16(oparms->path, oparms->cifs_sb);
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if (smb2_path == NULL) {
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rc = -ENOMEM;
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goto out;
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}
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smb2_data = kzalloc(sizeof(struct smb2_file_all_info) + PATH_MAX * 2,
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GFP_KERNEL);
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if (smb2_data == NULL) {
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rc = -ENOMEM;
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goto out;
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}
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oparms->desired_access |= FILE_READ_ATTRIBUTES;
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smb2_oplock = SMB2_OPLOCK_LEVEL_BATCH;
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rc = SMB2_open(xid, oparms, smb2_path, &smb2_oplock, smb2_data, NULL,
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NULL);
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if (rc)
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goto out;
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if (oparms->tcon->use_resilient) {
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nr_ioctl_req.Timeout = 0; /* use server default (120 seconds) */
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nr_ioctl_req.Reserved = 0;
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rc = SMB2_ioctl(xid, oparms->tcon, fid->persistent_fid,
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fid->volatile_fid, FSCTL_LMR_REQUEST_RESILIENCY,
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true /* is_fsctl */,
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(char *)&nr_ioctl_req, sizeof(nr_ioctl_req),
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NULL, NULL /* no return info */);
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if (rc == -EOPNOTSUPP) {
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cifs_dbg(VFS,
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"resiliency not supported by server, disabling\n");
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oparms->tcon->use_resilient = false;
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} else if (rc)
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cifs_dbg(FYI, "error %d setting resiliency\n", rc);
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rc = 0;
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}
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if (buf) {
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/* open response does not have IndexNumber field - get it */
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rc = SMB2_get_srv_num(xid, oparms->tcon, fid->persistent_fid,
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fid->volatile_fid,
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&smb2_data->IndexNumber);
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if (rc) {
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/* let get_inode_info disable server inode numbers */
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smb2_data->IndexNumber = 0;
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rc = 0;
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}
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move_smb2_info_to_cifs(buf, smb2_data);
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}
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*oplock = smb2_oplock;
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out:
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kfree(smb2_data);
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kfree(smb2_path);
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return rc;
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}
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int
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smb2_unlock_range(struct cifsFileInfo *cfile, struct file_lock *flock,
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const unsigned int xid)
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{
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int rc = 0, stored_rc;
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unsigned int max_num, num = 0, max_buf;
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struct smb2_lock_element *buf, *cur;
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struct cifs_tcon *tcon = tlink_tcon(cfile->tlink);
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struct cifsInodeInfo *cinode = CIFS_I(d_inode(cfile->dentry));
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struct cifsLockInfo *li, *tmp;
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__u64 length = 1 + flock->fl_end - flock->fl_start;
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struct list_head tmp_llist;
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INIT_LIST_HEAD(&tmp_llist);
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/*
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* Accessing maxBuf is racy with cifs_reconnect - need to store value
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* and check it for zero before using.
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*/
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max_buf = tcon->ses->server->maxBuf;
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if (!max_buf)
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return -EINVAL;
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BUILD_BUG_ON(sizeof(struct smb2_lock_element) > PAGE_SIZE);
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max_buf = min_t(unsigned int, max_buf, PAGE_SIZE);
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max_num = max_buf / sizeof(struct smb2_lock_element);
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buf = kcalloc(max_num, sizeof(struct smb2_lock_element), GFP_KERNEL);
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if (!buf)
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return -ENOMEM;
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cur = buf;
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down_write(&cinode->lock_sem);
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list_for_each_entry_safe(li, tmp, &cfile->llist->locks, llist) {
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if (flock->fl_start > li->offset ||
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(flock->fl_start + length) <
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(li->offset + li->length))
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continue;
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if (current->tgid != li->pid)
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continue;
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if (cinode->can_cache_brlcks) {
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/*
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* We can cache brlock requests - simply remove a lock
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* from the file's list.
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*/
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list_del(&li->llist);
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cifs_del_lock_waiters(li);
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kfree(li);
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continue;
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}
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cur->Length = cpu_to_le64(li->length);
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cur->Offset = cpu_to_le64(li->offset);
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cur->Flags = cpu_to_le32(SMB2_LOCKFLAG_UNLOCK);
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/*
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* We need to save a lock here to let us add it again to the
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* file's list if the unlock range request fails on the server.
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*/
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list_move(&li->llist, &tmp_llist);
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if (++num == max_num) {
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stored_rc = smb2_lockv(xid, tcon,
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cfile->fid.persistent_fid,
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cfile->fid.volatile_fid,
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current->tgid, num, buf);
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if (stored_rc) {
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/*
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* We failed on the unlock range request - add
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* all locks from the tmp list to the head of
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* the file's list.
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*/
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cifs_move_llist(&tmp_llist,
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&cfile->llist->locks);
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rc = stored_rc;
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} else
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/*
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* The unlock range request succeed - free the
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* tmp list.
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*/
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cifs_free_llist(&tmp_llist);
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cur = buf;
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num = 0;
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} else
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cur++;
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}
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if (num) {
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stored_rc = smb2_lockv(xid, tcon, cfile->fid.persistent_fid,
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cfile->fid.volatile_fid, current->tgid,
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num, buf);
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if (stored_rc) {
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cifs_move_llist(&tmp_llist, &cfile->llist->locks);
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rc = stored_rc;
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} else
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cifs_free_llist(&tmp_llist);
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}
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up_write(&cinode->lock_sem);
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kfree(buf);
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return rc;
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}
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static int
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smb2_push_mand_fdlocks(struct cifs_fid_locks *fdlocks, const unsigned int xid,
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struct smb2_lock_element *buf, unsigned int max_num)
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{
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int rc = 0, stored_rc;
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struct cifsFileInfo *cfile = fdlocks->cfile;
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struct cifsLockInfo *li;
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unsigned int num = 0;
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struct smb2_lock_element *cur = buf;
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struct cifs_tcon *tcon = tlink_tcon(cfile->tlink);
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list_for_each_entry(li, &fdlocks->locks, llist) {
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cur->Length = cpu_to_le64(li->length);
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cur->Offset = cpu_to_le64(li->offset);
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cur->Flags = cpu_to_le32(li->type |
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SMB2_LOCKFLAG_FAIL_IMMEDIATELY);
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if (++num == max_num) {
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stored_rc = smb2_lockv(xid, tcon,
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cfile->fid.persistent_fid,
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cfile->fid.volatile_fid,
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current->tgid, num, buf);
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if (stored_rc)
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rc = stored_rc;
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cur = buf;
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num = 0;
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} else
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cur++;
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}
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if (num) {
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stored_rc = smb2_lockv(xid, tcon,
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cfile->fid.persistent_fid,
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cfile->fid.volatile_fid,
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current->tgid, num, buf);
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if (stored_rc)
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rc = stored_rc;
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}
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return rc;
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}
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int
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smb2_push_mandatory_locks(struct cifsFileInfo *cfile)
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{
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int rc = 0, stored_rc;
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unsigned int xid;
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unsigned int max_num, max_buf;
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struct smb2_lock_element *buf;
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struct cifsInodeInfo *cinode = CIFS_I(d_inode(cfile->dentry));
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struct cifs_fid_locks *fdlocks;
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xid = get_xid();
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/*
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* Accessing maxBuf is racy with cifs_reconnect - need to store value
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* and check it for zero before using.
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*/
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max_buf = tlink_tcon(cfile->tlink)->ses->server->maxBuf;
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if (max_buf < sizeof(struct smb2_lock_element)) {
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free_xid(xid);
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return -EINVAL;
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}
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BUILD_BUG_ON(sizeof(struct smb2_lock_element) > PAGE_SIZE);
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max_buf = min_t(unsigned int, max_buf, PAGE_SIZE);
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max_num = max_buf / sizeof(struct smb2_lock_element);
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buf = kcalloc(max_num, sizeof(struct smb2_lock_element), GFP_KERNEL);
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if (!buf) {
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free_xid(xid);
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return -ENOMEM;
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}
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list_for_each_entry(fdlocks, &cinode->llist, llist) {
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stored_rc = smb2_push_mand_fdlocks(fdlocks, xid, buf, max_num);
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if (stored_rc)
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rc = stored_rc;
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}
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kfree(buf);
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free_xid(xid);
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return rc;
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}
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