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1 | /* | |
2 | * QEMU Enhanced Disk Format Table I/O | |
3 | * | |
4 | * Copyright IBM, Corp. 2010 | |
5 | * | |
6 | * Authors: | |
7 | * Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> | |
8 | * Anthony Liguori <aliguori@us.ibm.com> | |
9 | * | |
10 | * This work is licensed under the terms of the GNU LGPL, version 2 or later. | |
11 | * See the COPYING.LIB file in the top-level directory. | |
12 | * | |
13 | */ | |
14 | ||
15 | #include "qemu/osdep.h" | |
16 | #include "trace.h" | |
17 | #include "qemu/sockets.h" /* for EINPROGRESS on Windows */ | |
18 | #include "qed.h" | |
19 | #include "qemu/bswap.h" | |
20 | ||
21 | /* Called with table_lock held. */ | |
22 | static int qed_read_table(BDRVQEDState *s, uint64_t offset, QEDTable *table) | |
23 | { | |
24 | QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF( | |
25 | qiov, table->offsets, s->header.cluster_size * s->header.table_size); | |
26 | int noffsets; | |
27 | int i, ret; | |
28 | ||
29 | trace_qed_read_table(s, offset, table); | |
30 | ||
31 | qemu_co_mutex_unlock(&s->table_lock); | |
32 | ret = bdrv_preadv(s->bs->file, offset, &qiov); | |
33 | qemu_co_mutex_lock(&s->table_lock); | |
34 | if (ret < 0) { | |
35 | goto out; | |
36 | } | |
37 | ||
38 | /* Byteswap offsets */ | |
39 | noffsets = qiov.size / sizeof(uint64_t); | |
40 | for (i = 0; i < noffsets; i++) { | |
41 | table->offsets[i] = le64_to_cpu(table->offsets[i]); | |
42 | } | |
43 | ||
44 | ret = 0; | |
45 | out: | |
46 | /* Completion */ | |
47 | trace_qed_read_table_cb(s, table, ret); | |
48 | return ret; | |
49 | } | |
50 | ||
51 | /** | |
52 | * Write out an updated part or all of a table | |
53 | * | |
54 | * @s: QED state | |
55 | * @offset: Offset of table in image file, in bytes | |
56 | * @table: Table | |
57 | * @index: Index of first element | |
58 | * @n: Number of elements | |
59 | * @flush: Whether or not to sync to disk | |
60 | * | |
61 | * Called with table_lock held. | |
62 | */ | |
63 | static int qed_write_table(BDRVQEDState *s, uint64_t offset, QEDTable *table, | |
64 | unsigned int index, unsigned int n, bool flush) | |
65 | { | |
66 | unsigned int sector_mask = BDRV_SECTOR_SIZE / sizeof(uint64_t) - 1; | |
67 | unsigned int start, end, i; | |
68 | QEDTable *new_table; | |
69 | QEMUIOVector qiov; | |
70 | size_t len_bytes; | |
71 | int ret; | |
72 | ||
73 | trace_qed_write_table(s, offset, table, index, n); | |
74 | ||
75 | /* Calculate indices of the first and one after last elements */ | |
76 | start = index & ~sector_mask; | |
77 | end = (index + n + sector_mask) & ~sector_mask; | |
78 | ||
79 | len_bytes = (end - start) * sizeof(uint64_t); | |
80 | ||
81 | new_table = qemu_blockalign(s->bs, len_bytes); | |
82 | qemu_iovec_init_buf(&qiov, new_table->offsets, len_bytes); | |
83 | ||
84 | /* Byteswap table */ | |
85 | for (i = start; i < end; i++) { | |
86 | uint64_t le_offset = cpu_to_le64(table->offsets[i]); | |
87 | new_table->offsets[i - start] = le_offset; | |
88 | } | |
89 | ||
90 | /* Adjust for offset into table */ | |
91 | offset += start * sizeof(uint64_t); | |
92 | ||
93 | qemu_co_mutex_unlock(&s->table_lock); | |
94 | ret = bdrv_pwritev(s->bs->file, offset, &qiov); | |
95 | qemu_co_mutex_lock(&s->table_lock); | |
96 | trace_qed_write_table_cb(s, table, flush, ret); | |
97 | if (ret < 0) { | |
98 | goto out; | |
99 | } | |
100 | ||
101 | if (flush) { | |
102 | ret = bdrv_flush(s->bs); | |
103 | if (ret < 0) { | |
104 | goto out; | |
105 | } | |
106 | } | |
107 | ||
108 | ret = 0; | |
109 | out: | |
110 | qemu_vfree(new_table); | |
111 | return ret; | |
112 | } | |
113 | ||
114 | int qed_read_l1_table_sync(BDRVQEDState *s) | |
115 | { | |
116 | return qed_read_table(s, s->header.l1_table_offset, s->l1_table); | |
117 | } | |
118 | ||
119 | /* Called with table_lock held. */ | |
120 | int qed_write_l1_table(BDRVQEDState *s, unsigned int index, unsigned int n) | |
121 | { | |
122 | BLKDBG_EVENT(s->bs->file, BLKDBG_L1_UPDATE); | |
123 | return qed_write_table(s, s->header.l1_table_offset, | |
124 | s->l1_table, index, n, false); | |
125 | } | |
126 | ||
127 | int qed_write_l1_table_sync(BDRVQEDState *s, unsigned int index, | |
128 | unsigned int n) | |
129 | { | |
130 | return qed_write_l1_table(s, index, n); | |
131 | } | |
132 | ||
133 | /* Called with table_lock held. */ | |
134 | int qed_read_l2_table(BDRVQEDState *s, QEDRequest *request, uint64_t offset) | |
135 | { | |
136 | int ret; | |
137 | ||
138 | qed_unref_l2_cache_entry(request->l2_table); | |
139 | ||
140 | /* Check for cached L2 entry */ | |
141 | request->l2_table = qed_find_l2_cache_entry(&s->l2_cache, offset); | |
142 | if (request->l2_table) { | |
143 | return 0; | |
144 | } | |
145 | ||
146 | request->l2_table = qed_alloc_l2_cache_entry(&s->l2_cache); | |
147 | request->l2_table->table = qed_alloc_table(s); | |
148 | ||
149 | BLKDBG_EVENT(s->bs->file, BLKDBG_L2_LOAD); | |
150 | ret = qed_read_table(s, offset, request->l2_table->table); | |
151 | ||
152 | if (ret) { | |
153 | /* can't trust loaded L2 table anymore */ | |
154 | qed_unref_l2_cache_entry(request->l2_table); | |
155 | request->l2_table = NULL; | |
156 | } else { | |
157 | request->l2_table->offset = offset; | |
158 | ||
159 | qed_commit_l2_cache_entry(&s->l2_cache, request->l2_table); | |
160 | ||
161 | /* This is guaranteed to succeed because we just committed the entry | |
162 | * to the cache. | |
163 | */ | |
164 | request->l2_table = qed_find_l2_cache_entry(&s->l2_cache, offset); | |
165 | assert(request->l2_table != NULL); | |
166 | } | |
167 | ||
168 | return ret; | |
169 | } | |
170 | ||
171 | int qed_read_l2_table_sync(BDRVQEDState *s, QEDRequest *request, uint64_t offset) | |
172 | { | |
173 | return qed_read_l2_table(s, request, offset); | |
174 | } | |
175 | ||
176 | /* Called with table_lock held. */ | |
177 | int qed_write_l2_table(BDRVQEDState *s, QEDRequest *request, | |
178 | unsigned int index, unsigned int n, bool flush) | |
179 | { | |
180 | BLKDBG_EVENT(s->bs->file, BLKDBG_L2_UPDATE); | |
181 | return qed_write_table(s, request->l2_table->offset, | |
182 | request->l2_table->table, index, n, flush); | |
183 | } | |
184 | ||
185 | int qed_write_l2_table_sync(BDRVQEDState *s, QEDRequest *request, | |
186 | unsigned int index, unsigned int n, bool flush) | |
187 | { | |
188 | return qed_write_l2_table(s, request, index, n, flush); | |
189 | } |