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diff --git a/fs/xfs/libxfs/xfs_log_rlimit.c b/fs/xfs/libxfs/xfs_log_rlimit.c
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1/*
2 * Copyright (c) 2013 Jie Liu.
3 * All Rights Reserved.
4 *
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU General Public License as
7 * published by the Free Software Foundation.
8 *
9 * This program is distributed in the hope that it would be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write the Free Software Foundation,
16 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
17 */
18#include "xfs.h"
19#include "xfs_fs.h"
20#include "xfs_shared.h"
21#include "xfs_format.h"
22#include "xfs_log_format.h"
23#include "xfs_trans_resv.h"
24#include "xfs_ag.h"
25#include "xfs_sb.h"
26#include "xfs_mount.h"
27#include "xfs_da_format.h"
28#include "xfs_trans_space.h"
29#include "xfs_inode.h"
30#include "xfs_da_btree.h"
31#include "xfs_attr_leaf.h"
32#include "xfs_bmap_btree.h"
33
34/*
35 * Calculate the maximum length in bytes that would be required for a local
36 * attribute value as large attributes out of line are not logged.
37 */
38STATIC int
39xfs_log_calc_max_attrsetm_res(
40 struct xfs_mount *mp)
41{
42 int size;
43 int nblks;
44
45 size = xfs_attr_leaf_entsize_local_max(mp->m_attr_geo->blksize) -
46 MAXNAMELEN - 1;
47 nblks = XFS_DAENTER_SPACE_RES(mp, XFS_ATTR_FORK);
48 nblks += XFS_B_TO_FSB(mp, size);
49 nblks += XFS_NEXTENTADD_SPACE_RES(mp, size, XFS_ATTR_FORK);
50
51 return M_RES(mp)->tr_attrsetm.tr_logres +
52 M_RES(mp)->tr_attrsetrt.tr_logres * nblks;
53}
54
55/*
56 * Iterate over the log space reservation table to figure out and return
57 * the maximum one in terms of the pre-calculated values which were done
58 * at mount time.
59 */
60STATIC void
61xfs_log_get_max_trans_res(
62 struct xfs_mount *mp,
63 struct xfs_trans_res *max_resp)
64{
65 struct xfs_trans_res *resp;
66 struct xfs_trans_res *end_resp;
67 int log_space = 0;
68 int attr_space;
69
70 attr_space = xfs_log_calc_max_attrsetm_res(mp);
71
72 resp = (struct xfs_trans_res *)M_RES(mp);
73 end_resp = (struct xfs_trans_res *)(M_RES(mp) + 1);
74 for (; resp < end_resp; resp++) {
75 int tmp = resp->tr_logcount > 1 ?
76 resp->tr_logres * resp->tr_logcount :
77 resp->tr_logres;
78 if (log_space < tmp) {
79 log_space = tmp;
80 *max_resp = *resp; /* struct copy */
81 }
82 }
83
84 if (attr_space > log_space) {
85 *max_resp = M_RES(mp)->tr_attrsetm; /* struct copy */
86 max_resp->tr_logres = attr_space;
87 }
88}
89
90/*
91 * Calculate the minimum valid log size for the given superblock configuration.
92 * Used to calculate the minimum log size at mkfs time, and to determine if
93 * the log is large enough or not at mount time. Returns the minimum size in
94 * filesystem block size units.
95 */
96int
97xfs_log_calc_minimum_size(
98 struct xfs_mount *mp)
99{
100 struct xfs_trans_res tres = {0};
101 int max_logres;
102 int min_logblks = 0;
103 int lsunit = 0;
104
105 xfs_log_get_max_trans_res(mp, &tres);
106
107 max_logres = xfs_log_calc_unit_res(mp, tres.tr_logres);
108 if (tres.tr_logcount > 1)
109 max_logres *= tres.tr_logcount;
110
111 if (xfs_sb_version_haslogv2(&mp->m_sb) && mp->m_sb.sb_logsunit > 1)
112 lsunit = BTOBB(mp->m_sb.sb_logsunit);
113
114 /*
115 * Two factors should be taken into account for calculating the minimum
116 * log space.
117 * 1) The fundamental limitation is that no single transaction can be
118 * larger than half size of the log.
119 *
120 * From mkfs.xfs, this is considered by the XFS_MIN_LOG_FACTOR
121 * define, which is set to 3. That means we can definitely fit
122 * maximally sized 2 transactions in the log. We'll use this same
123 * value here.
124 *
125 * 2) If the lsunit option is specified, a transaction requires 2 LSU
126 * for the reservation because there are two log writes that can
127 * require padding - the transaction data and the commit record which
128 * are written separately and both can require padding to the LSU.
129 * Consider that we can have an active CIL reservation holding 2*LSU,
130 * but the CIL is not over a push threshold, in this case, if we
131 * don't have enough log space for at one new transaction, which
132 * includes another 2*LSU in the reservation, we will run into dead
133 * loop situation in log space grant procedure. i.e.
134 * xlog_grant_head_wait().
135 *
136 * Hence the log size needs to be able to contain two maximally sized
137 * and padded transactions, which is (2 * (2 * LSU + maxlres)).
138 *
139 * Also, the log size should be a multiple of the log stripe unit, round
140 * it up to lsunit boundary if lsunit is specified.
141 */
142 if (lsunit) {
143 min_logblks = roundup_64(BTOBB(max_logres), lsunit) +
144 2 * lsunit;
145 } else
146 min_logblks = BTOBB(max_logres) + 2 * BBSIZE;
147 min_logblks *= XFS_MIN_LOG_FACTOR;
148
149 return XFS_BB_TO_FSB(mp, min_logblks);
150}
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