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_inode.h"
16 #include "xfs_da_btree.h"
17 #include "xfs_attr_leaf.h"
18 #include "xfs_bmap_btree.h"
19
20 /*
21 * Calculate the maximum length in bytes that would be required for a local
22 * attribute value as large attributes out of line are not logged.
23 */
24 STATIC int
xfs_log_calc_max_attrsetm_res(struct xfs_mount * mp)25 xfs_log_calc_max_attrsetm_res(
26 struct xfs_mount *mp)
27 {
28 int size;
29 int nblks;
30
31 size = xfs_attr_leaf_entsize_local_max(mp->m_attr_geo->blksize) -
32 MAXNAMELEN - 1;
33 nblks = XFS_DAENTER_SPACE_RES(mp, XFS_ATTR_FORK);
34 nblks += XFS_B_TO_FSB(mp, size);
35 nblks += XFS_NEXTENTADD_SPACE_RES(mp, size, XFS_ATTR_FORK);
36
37 return M_RES(mp)->tr_attrsetm.tr_logres +
38 M_RES(mp)->tr_attrsetrt.tr_logres * nblks;
39 }
40
41 /*
42 * Iterate over the log space reservation table to figure out and return
43 * the maximum one in terms of the pre-calculated values which were done
44 * at mount time.
45 */
46 void
xfs_log_get_max_trans_res(struct xfs_mount * mp,struct xfs_trans_res * max_resp)47 xfs_log_get_max_trans_res(
48 struct xfs_mount *mp,
49 struct xfs_trans_res *max_resp)
50 {
51 struct xfs_trans_res *resp;
52 struct xfs_trans_res *end_resp;
53 int log_space = 0;
54 int attr_space;
55
56 attr_space = xfs_log_calc_max_attrsetm_res(mp);
57
58 resp = (struct xfs_trans_res *)M_RES(mp);
59 end_resp = (struct xfs_trans_res *)(M_RES(mp) + 1);
60 for (; resp < end_resp; resp++) {
61 int tmp = resp->tr_logcount > 1 ?
62 resp->tr_logres * resp->tr_logcount :
63 resp->tr_logres;
64 if (log_space < tmp) {
65 log_space = tmp;
66 *max_resp = *resp; /* struct copy */
67 }
68 }
69
70 if (attr_space > log_space) {
71 *max_resp = M_RES(mp)->tr_attrsetm; /* struct copy */
72 max_resp->tr_logres = attr_space;
73 }
74 }
75
76 /*
77 * Calculate the minimum valid log size for the given superblock configuration.
78 * Used to calculate the minimum log size at mkfs time, and to determine if
79 * the log is large enough or not at mount time. Returns the minimum size in
80 * filesystem block size units.
81 */
82 int
xfs_log_calc_minimum_size(struct xfs_mount * mp)83 xfs_log_calc_minimum_size(
84 struct xfs_mount *mp)
85 {
86 struct xfs_trans_res tres = {0};
87 int max_logres;
88 int min_logblks = 0;
89 int lsunit = 0;
90
91 xfs_log_get_max_trans_res(mp, &tres);
92
93 max_logres = xfs_log_calc_unit_res(mp, tres.tr_logres);
94 if (tres.tr_logcount > 1)
95 max_logres *= tres.tr_logcount;
96
97 if (xfs_sb_version_haslogv2(&mp->m_sb) && mp->m_sb.sb_logsunit > 1)
98 lsunit = BTOBB(mp->m_sb.sb_logsunit);
99
100 /*
101 * Two factors should be taken into account for calculating the minimum
102 * log space.
103 * 1) The fundamental limitation is that no single transaction can be
104 * larger than half size of the log.
105 *
106 * From mkfs.xfs, this is considered by the XFS_MIN_LOG_FACTOR
107 * define, which is set to 3. That means we can definitely fit
108 * maximally sized 2 transactions in the log. We'll use this same
109 * value here.
110 *
111 * 2) If the lsunit option is specified, a transaction requires 2 LSU
112 * for the reservation because there are two log writes that can
113 * require padding - the transaction data and the commit record which
114 * are written separately and both can require padding to the LSU.
115 * Consider that we can have an active CIL reservation holding 2*LSU,
116 * but the CIL is not over a push threshold, in this case, if we
117 * don't have enough log space for at one new transaction, which
118 * includes another 2*LSU in the reservation, we will run into dead
119 * loop situation in log space grant procedure. i.e.
120 * xlog_grant_head_wait().
121 *
122 * Hence the log size needs to be able to contain two maximally sized
123 * and padded transactions, which is (2 * (2 * LSU + maxlres)).
124 *
125 * Also, the log size should be a multiple of the log stripe unit, round
126 * it up to lsunit boundary if lsunit is specified.
127 */
128 if (lsunit) {
129 min_logblks = roundup_64(BTOBB(max_logres), lsunit) +
130 2 * lsunit;
131 } else
132 min_logblks = BTOBB(max_logres) + 2 * BBSIZE;
133 min_logblks *= XFS_MIN_LOG_FACTOR;
134
135 return XFS_BB_TO_FSB(mp, min_logblks);
136 }
137