1 /*
2  * Copyright (c) 2007 The DragonFly Project.  All rights reserved.
3  *
4  * This code is derived from software contributed to The DragonFly Project
5  * by Matthew Dillon <dillon@backplane.com>
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  *
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in
15  *    the documentation and/or other materials provided with the
16  *    distribution.
17  * 3. Neither the name of The DragonFly Project nor the names of its
18  *    contributors may be used to endorse or promote products derived
19  *    from this software without specific, prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
22  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
23  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
24  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
25  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
26  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
27  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
28  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
29  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
30  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
31  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  *
34  * $DragonFly: src/sys/vfs/hammer/hammer_transaction.c,v 1.9 2008/02/08 08:31:00 dillon Exp $
35  */
36 
37 #include "hammer.h"
38 
39 void
40 hammer_start_transaction(struct hammer_transaction *trans,
41 			 struct hammer_mount *hmp)
42 {
43 	int error;
44 
45 	trans->hmp = hmp;
46 	trans->rootvol = hammer_get_root_volume(hmp, &error);
47 	KKASSERT(error == 0);
48 	trans->tid = hammer_alloc_tid(trans);
49 }
50 
51 void
52 hammer_start_transaction_tid(struct hammer_transaction *trans,
53 			     struct hammer_mount *hmp, hammer_tid_t tid)
54 {
55 	int error;
56 
57 	trans->hmp = hmp;
58 	trans->rootvol = hammer_get_root_volume(hmp, &error);
59 	KKASSERT(error == 0);
60 	trans->tid = tid;
61 }
62 
63 void
64 hammer_abort_transaction(struct hammer_transaction *trans)
65 {
66 	hammer_rel_volume(trans->rootvol, 0);
67 }
68 
69 void
70 hammer_commit_transaction(struct hammer_transaction *trans)
71 {
72 	hammer_rel_volume(trans->rootvol, 0);
73 }
74 
75 /*
76  * Note: Successive transaction ids must be at least 2 apart so the
77  * B-Tree code can make a separator that does not match either the
78  * left or right hand sides.
79  */
80 hammer_tid_t
81 hammer_alloc_tid(hammer_transaction_t trans)
82 {
83 	hammer_volume_ondisk_t ondisk;
84 	struct timespec ts;
85 	hammer_tid_t tid;
86 
87 	getnanotime(&ts);
88 	tid = ts.tv_sec * 1000000000LL + ts.tv_nsec;
89 	hammer_modify_volume(trans->rootvol, NULL, 0);
90 	ondisk = trans->rootvol->ondisk;
91 	if (tid < ondisk->vol0_next_tid)
92 		tid = ondisk->vol0_next_tid;
93 	if (tid == 0xFFFFFFFFFFFFFFFFULL)
94 		panic("hammer_start_transaction: Ran out of TIDs!");
95 	if (hammer_debug_tid) {
96 		kprintf("alloc_tid %016llx (0x%08x)\n",
97 			tid, (int)(tid / 1000000000LL));
98 	}
99 	ondisk->vol0_next_tid = tid + 2;
100 
101 	return(tid);
102 }
103 
104