source/include/locking.h

   1 /*
   2    Unix SMB/CIFS implementation.
   3    SMB parameters and setup, plus a whole lot more.
   4
   5    Copyright (C) Jeremy Allison   2006
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 2 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program; if not, write to the Free Software
  19    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  20 */
  21
  22 #ifndef _LOCKING_H
  23 #define _LOCKING_H
  24
  25 /* passed to br lock code - the UNLOCK_LOCK should never be stored into the tdb
  26    and is used in calculating POSIX unlock ranges only. We differentiate between
  27    PENDING read and write locks to allow posix lock downgrades to trigger a lock
  28    re-evaluation. */
  29
  30 enum brl_type {READ_LOCK, WRITE_LOCK, PENDING_READ_LOCK, PENDING_WRITE_LOCK, UNLOCK_LOCK};
  31 enum brl_flavour {WINDOWS_LOCK = 0, POSIX_LOCK = 1};
  32
  33 #define IS_PENDING_LOCK(type) ((type) == PENDING_READ_LOCK || (type) == PENDING_WRITE_LOCK)
  34
  35 /* This contains elements that differentiate locks. The smbpid is a
  36    client supplied pid, and is essentially the locking context for
  37    this client */
  38
  39 struct lock_context {
  40         uint32 smbpid;
  41         uint16 tid;
  42         struct process_id pid;
  43 };
  44
  45 /* The key used in the brlock database. */
  46
  47 struct lock_key {
  48         SMB_DEV_T device;
  49         SMB_INO_T inode;
  50 };
  51
  52 struct files_struct;
  53
  54 struct byte_range_lock {
  55         struct files_struct *fsp;
  56         unsigned int num_locks;
  57         BOOL modified;
  58         BOOL read_only;
  59         struct lock_key key;
  60         void *lock_data;
  61 };
  62
  63 #define BRLOCK_FN_CAST() \
  64         void (*)(SMB_DEV_T dev, SMB_INO_T ino, struct process_id pid, \
  65                                  enum brl_type lock_type, \
  66                                  enum brl_flavour lock_flav, \
  67                                  br_off start, br_off size)
  68
  69 #define BRLOCK_FN(fn) \
  70         void (*fn)(SMB_DEV_T dev, SMB_INO_T ino, struct process_id pid, \
  71                                  enum brl_type lock_type, \
  72                                  enum brl_flavour lock_flav, \
  73                                  br_off start, br_off size)
  74
  75 /* Internal structure in brlock.tdb.
  76    The data in brlock records is an unsorted linear array of these
  77    records.  It is unnecessary to store the count as tdb provides the
  78    size of the record */
  79
  80 struct lock_struct {
  81         struct lock_context context;
  82         br_off start;
  83         br_off size;
  84         uint16 fnum;
  85         enum brl_type lock_type;
  86         enum brl_flavour lock_flav;
  87 };
  88
  89 #endif /* _LOCKING_H_ */