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 3 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, see <http://www.gnu.org/licenses/>.
  19 */
  20
  21 #ifndef _LOCKING_H
  22 #define _LOCKING_H
  23
  24 /* passed to br lock code - the UNLOCK_LOCK should never be stored into the tdb
  25    and is used in calculating POSIX unlock ranges only. We differentiate between
  26    PENDING read and write locks to allow posix lock downgrades to trigger a lock
  27    re-evaluation. */
  28
  29 enum brl_type {READ_LOCK, WRITE_LOCK, PENDING_READ_LOCK, PENDING_WRITE_LOCK, UNLOCK_LOCK};
  30 enum brl_flavour {WINDOWS_LOCK = 0, POSIX_LOCK = 1};
  31
  32 #define IS_PENDING_LOCK(type) ((type) == PENDING_READ_LOCK || (type) == PENDING_WRITE_LOCK)
  33
  34 /* This contains elements that differentiate locks. The smbpid is a
  35    client supplied pid, and is essentially the locking context for
  36    this client */
  37
  38 struct lock_context {
  39         uint32 smbpid;
  40         uint16 tid;
  41         struct server_id pid;
  42 };
  43
  44 struct files_struct;
  45
  46 struct file_id {
  47         /* we don't use SMB_DEV_T and SMB_INO_T as we want a fixed size here,
  48            and we may be using file system specific code to fill in something
  49            other than a dev_t for the device */
  50         uint64_t devid;
  51         uint64_t inode;
  52 };
  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 file_id key;
  60         struct lock_struct *lock_data;
  61         struct db_record *record;
  62 };
  63
  64 /* Internal structure in brlock.tdb.
  65    The data in brlock records is an unsorted linear array of these
  66    records.  It is unnecessary to store the count as tdb provides the
  67    size of the record */
  68
  69 struct lock_struct {
  70         struct lock_context context;
  71         br_off start;
  72         br_off size;
  73         uint16 fnum;
  74         enum brl_type lock_type;
  75         enum brl_flavour lock_flav;
  76 };
  77
  78 #endif /* _LOCKING_H_ */