1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright (c) 2013 Jie Liu.
4 * All Rights Reserved.
5 */
6 #include "xfs.h"
7 #include "xfs_fs.h"
8 #include "xfs_shared.h"
9 #include "xfs_format.h"
10 #include "xfs_log_format.h"
11 #include "xfs_trans_resv.h"
12 #include "xfs_mount.h"
13 #include "xfs_da_format.h"
14 #include "xfs_trans_space.h"
15 #include "xfs_da_btree.h"
16 #include "xfs_bmap_btree.h"
17
18 /*
19 * Calculate the maximum length in bytes that would be required for a local
20 * attribute value as large attributes out of line are not logged.
21 */
22 STATIC int
xfs_log_calc_max_attrsetm_res(struct xfs_mount * mp)23 xfs_log_calc_max_attrsetm_res(
24 struct xfs_mount *mp)
25 {
26 int size;
27 int nblks;
28
29 size = xfs_attr_leaf_entsize_local_max(mp->m_attr_geo->blksize) -
30 MAXNAMELEN - 1;
31 nblks = XFS_DAENTER_SPACE_RES(mp, XFS_ATTR_FORK);
32 nblks += XFS_B_TO_FSB(mp, size);
33 nblks += XFS_NEXTENTADD_SPACE_RES(mp, size, XFS_ATTR_FORK);
34
35 return M_RES(mp)->tr_attrsetm.tr_logres +
36 M_RES(mp)->tr_attrsetrt.tr_logres * nblks;
37 }
38
39 /*
40 * Iterate over the log space reservation table to figure out and return
41 * the maximum one in terms of the pre-calculated values which were done
42 * at mount time.
43 */
44 void
xfs_log_get_max_trans_res(struct xfs_mount * mp,struct xfs_trans_res * max_resp)45 xfs_log_get_max_trans_res(
46 struct xfs_mount *mp,
47 struct xfs_trans_res *max_resp)
48 {
49 struct xfs_trans_res *resp;
50 struct xfs_trans_res *end_resp;
51 int log_space = 0;
52 int attr_space;
53
54 attr_space = xfs_log_calc_max_attrsetm_res(mp);
55
56 resp = (struct xfs_trans_res *)M_RES(mp);
57 end_resp = (struct xfs_trans_res *)(M_RES(mp) + 1);
58 for (; resp < end_resp; resp++) {
59 int tmp = resp->tr_logcount > 1 ?
60 resp->tr_logres * resp->tr_logcount :
61 resp->tr_logres;
62 if (log_space < tmp) {
63 log_space = tmp;
64 *max_resp = *resp; /* struct copy */
65 }
66 }
67
68 if (attr_space > log_space) {
69 *max_resp = M_RES(mp)->tr_attrsetm; /* struct copy */
70 max_resp->tr_logres = attr_space;
71 }
72 }
73
74 /*
75 * Calculate the minimum valid log size for the given superblock configuration.
76 * Used to calculate the minimum log size at mkfs time, and to determine if
77 * the log is large enough or not at mount time. Returns the minimum size in
78 * filesystem block size units.
79 */
80 int
xfs_log_calc_minimum_size(struct xfs_mount * mp)81 xfs_log_calc_minimum_size(
82 struct xfs_mount *mp)
83 {
84 struct xfs_trans_res tres = {0};
85 int max_logres;
86 int min_logblks = 0;
87 int lsunit = 0;
88
89 xfs_log_get_max_trans_res(mp, &tres);
90
91 max_logres = xfs_log_calc_unit_res(mp, tres.tr_logres);
92 if (tres.tr_logcount > 1)
93 max_logres *= tres.tr_logcount;
94
95 if (xfs_has_logv2(mp) && mp->m_sb.sb_logsunit > 1)
96 lsunit = BTOBB(mp->m_sb.sb_logsunit);
97
98 /*
99 * Two factors should be taken into account for calculating the minimum
100 * log space.
101 * 1) The fundamental limitation is that no single transaction can be
102 * larger than half size of the log.
103 *
104 * From mkfs.xfs, this is considered by the XFS_MIN_LOG_FACTOR
105 * define, which is set to 3. That means we can definitely fit
106 * maximally sized 2 transactions in the log. We'll use this same
107 * value here.
108 *
109 * 2) If the lsunit option is specified, a transaction requires 2 LSU
110 * for the reservation because there are two log writes that can
111 * require padding - the transaction data and the commit record which
112 * are written separately and both can require padding to the LSU.
113 * Consider that we can have an active CIL reservation holding 2*LSU,
114 * but the CIL is not over a push threshold, in this case, if we
115 * don't have enough log space for at one new transaction, which
116 * includes another 2*LSU in the reservation, we will run into dead
117 * loop situation in log space grant procedure. i.e.
118 * xlog_grant_head_wait().
119 *
120 * Hence the log size needs to be able to contain two maximally sized
121 * and padded transactions, which is (2 * (2 * LSU + maxlres)).
122 *
123 * Also, the log size should be a multiple of the log stripe unit, round
124 * it up to lsunit boundary if lsunit is specified.
125 */
126 if (lsunit) {
127 min_logblks = roundup_64(BTOBB(max_logres), lsunit) +
128 2 * lsunit;
129 } else
130 min_logblks = BTOBB(max_logres) + 2 * BBSIZE;
131 min_logblks *= XFS_MIN_LOG_FACTOR;
132
133 return XFS_BB_TO_FSB(mp, min_logblks);
134 }
135
