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 #include "xfs_trace.h"
18
19 /*
20 * Calculate the maximum length in bytes that would be required for a local
21 * attribute value as large attributes out of line are not logged.
22 */
23 STATIC int
xfs_log_calc_max_attrsetm_res(struct xfs_mount * mp)24 xfs_log_calc_max_attrsetm_res(
25 struct xfs_mount *mp)
26 {
27 int size;
28 int nblks;
29
30 size = xfs_attr_leaf_entsize_local_max(mp->m_attr_geo->blksize) -
31 MAXNAMELEN - 1;
32 nblks = XFS_DAENTER_SPACE_RES(mp, XFS_ATTR_FORK);
33 nblks += XFS_B_TO_FSB(mp, size);
34 nblks += XFS_NEXTENTADD_SPACE_RES(mp, size, XFS_ATTR_FORK);
35
36 return M_RES(mp)->tr_attrsetm.tr_logres +
37 M_RES(mp)->tr_attrsetrt.tr_logres * nblks;
38 }
39
40 /*
41 * Compute an alternate set of log reservation sizes for use exclusively with
42 * minimum log size calculations.
43 */
44 static void
xfs_log_calc_trans_resv_for_minlogblocks(struct xfs_mount * mp,struct xfs_trans_resv * resv)45 xfs_log_calc_trans_resv_for_minlogblocks(
46 struct xfs_mount *mp,
47 struct xfs_trans_resv *resv)
48 {
49 unsigned int rmap_maxlevels = mp->m_rmap_maxlevels;
50
51 /*
52 * In the early days of rmap+reflink, we always set the rmap maxlevels
53 * to 9 even if the AG was small enough that it would never grow to
54 * that height. Transaction reservation sizes influence the minimum
55 * log size calculation, which influences the size of the log that mkfs
56 * creates. Use the old value here to ensure that newly formatted
57 * small filesystems will mount on older kernels.
58 */
59 if (xfs_has_rmapbt(mp) && xfs_has_reflink(mp))
60 mp->m_rmap_maxlevels = XFS_OLD_REFLINK_RMAP_MAXLEVELS;
61
62 xfs_trans_resv_calc(mp, resv);
63
64 if (xfs_has_reflink(mp)) {
65 /*
66 * In the early days of reflink, typical log operation counts
67 * were greatly overestimated.
68 */
69 resv->tr_write.tr_logcount = XFS_WRITE_LOG_COUNT_REFLINK;
70 resv->tr_itruncate.tr_logcount =
71 XFS_ITRUNCATE_LOG_COUNT_REFLINK;
72 resv->tr_qm_dqalloc.tr_logcount = XFS_WRITE_LOG_COUNT_REFLINK;
73 } else if (xfs_has_rmapbt(mp)) {
74 /*
75 * In the early days of non-reflink rmap, the impact of rmapbt
76 * updates on log counts were not taken into account at all.
77 */
78 resv->tr_write.tr_logcount = XFS_WRITE_LOG_COUNT;
79 resv->tr_itruncate.tr_logcount = XFS_ITRUNCATE_LOG_COUNT;
80 resv->tr_qm_dqalloc.tr_logcount = XFS_WRITE_LOG_COUNT;
81 }
82
83 /*
84 * In the early days of reflink, we did not use deferred refcount
85 * update log items, so log reservations must be recomputed using the
86 * old calculations.
87 */
88 resv->tr_write.tr_logres =
89 xfs_calc_write_reservation_minlogsize(mp);
90 resv->tr_itruncate.tr_logres =
91 xfs_calc_itruncate_reservation_minlogsize(mp);
92 resv->tr_qm_dqalloc.tr_logres =
93 xfs_calc_qm_dqalloc_reservation_minlogsize(mp);
94
95 /* Put everything back the way it was. This goes at the end. */
96 mp->m_rmap_maxlevels = rmap_maxlevels;
97 }
98
99 /*
100 * Iterate over the log space reservation table to figure out and return
101 * the maximum one in terms of the pre-calculated values which were done
102 * at mount time.
103 */
104 void
xfs_log_get_max_trans_res(struct xfs_mount * mp,struct xfs_trans_res * max_resp)105 xfs_log_get_max_trans_res(
106 struct xfs_mount *mp,
107 struct xfs_trans_res *max_resp)
108 {
109 struct xfs_trans_resv resv = {};
110 struct xfs_trans_res *resp;
111 struct xfs_trans_res *end_resp;
112 unsigned int i;
113 int log_space = 0;
114 int attr_space;
115
116 attr_space = xfs_log_calc_max_attrsetm_res(mp);
117
118 xfs_log_calc_trans_resv_for_minlogblocks(mp, &resv);
119
120 resp = (struct xfs_trans_res *)&resv;
121 end_resp = (struct xfs_trans_res *)(&resv + 1);
122 for (i = 0; resp < end_resp; i++, resp++) {
123 int tmp = resp->tr_logcount > 1 ?
124 resp->tr_logres * resp->tr_logcount :
125 resp->tr_logres;
126
127 trace_xfs_trans_resv_calc_minlogsize(mp, i, resp);
128 if (log_space < tmp) {
129 log_space = tmp;
130 *max_resp = *resp; /* struct copy */
131 }
132 }
133
134 if (attr_space > log_space) {
135 *max_resp = resv.tr_attrsetm; /* struct copy */
136 max_resp->tr_logres = attr_space;
137 }
138 trace_xfs_log_get_max_trans_res(mp, max_resp);
139 }
140
141 /*
142 * Calculate the minimum valid log size for the given superblock configuration.
143 * Used to calculate the minimum log size at mkfs time, and to determine if
144 * the log is large enough or not at mount time. Returns the minimum size in
145 * filesystem block size units.
146 */
147 int
xfs_log_calc_minimum_size(struct xfs_mount * mp)148 xfs_log_calc_minimum_size(
149 struct xfs_mount *mp)
150 {
151 struct xfs_trans_res tres = {0};
152 int max_logres;
153 int min_logblks = 0;
154 int lsunit = 0;
155
156 xfs_log_get_max_trans_res(mp, &tres);
157
158 max_logres = xfs_log_calc_unit_res(mp, tres.tr_logres);
159 if (tres.tr_logcount > 1)
160 max_logres *= tres.tr_logcount;
161
162 if (xfs_has_logv2(mp) && mp->m_sb.sb_logsunit > 1)
163 lsunit = BTOBB(mp->m_sb.sb_logsunit);
164
165 /*
166 * Two factors should be taken into account for calculating the minimum
167 * log space.
168 * 1) The fundamental limitation is that no single transaction can be
169 * larger than half size of the log.
170 *
171 * From mkfs.xfs, this is considered by the XFS_MIN_LOG_FACTOR
172 * define, which is set to 3. That means we can definitely fit
173 * maximally sized 2 transactions in the log. We'll use this same
174 * value here.
175 *
176 * 2) If the lsunit option is specified, a transaction requires 2 LSU
177 * for the reservation because there are two log writes that can
178 * require padding - the transaction data and the commit record which
179 * are written separately and both can require padding to the LSU.
180 * Consider that we can have an active CIL reservation holding 2*LSU,
181 * but the CIL is not over a push threshold, in this case, if we
182 * don't have enough log space for at one new transaction, which
183 * includes another 2*LSU in the reservation, we will run into dead
184 * loop situation in log space grant procedure. i.e.
185 * xlog_grant_head_wait().
186 *
187 * Hence the log size needs to be able to contain two maximally sized
188 * and padded transactions, which is (2 * (2 * LSU + maxlres)).
189 *
190 * Also, the log size should be a multiple of the log stripe unit, round
191 * it up to lsunit boundary if lsunit is specified.
192 */
193 if (lsunit) {
194 min_logblks = roundup_64(BTOBB(max_logres), lsunit) +
195 2 * lsunit;
196 } else
197 min_logblks = BTOBB(max_logres) + 2 * BBSIZE;
198 min_logblks *= XFS_MIN_LOG_FACTOR;
199
200 return XFS_BB_TO_FSB(mp, min_logblks);
201 }
202