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1.1 root 1: /*
2: * QEMU Enhanced Disk Format Table I/O
3: *
4: * Copyright IBM, Corp. 2010
5: *
6: * Authors:
7: * Stefan Hajnoczi <[email protected]>
8: * Anthony Liguori <[email protected]>
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 "trace.h"
16: #include "qemu_socket.h" /* for EINPROGRESS on Windows */
17: #include "qed.h"
18:
19: typedef struct {
20: GenericCB gencb;
21: BDRVQEDState *s;
22: QEDTable *table;
23:
24: struct iovec iov;
25: QEMUIOVector qiov;
26: } QEDReadTableCB;
27:
28: static void qed_read_table_cb(void *opaque, int ret)
29: {
30: QEDReadTableCB *read_table_cb = opaque;
31: QEDTable *table = read_table_cb->table;
32: int noffsets = read_table_cb->iov.iov_len / sizeof(uint64_t);
33: int i;
34:
35: /* Handle I/O error */
36: if (ret) {
37: goto out;
38: }
39:
40: /* Byteswap offsets */
41: for (i = 0; i < noffsets; i++) {
42: table->offsets[i] = le64_to_cpu(table->offsets[i]);
43: }
44:
45: out:
46: /* Completion */
47: trace_qed_read_table_cb(read_table_cb->s, read_table_cb->table, ret);
48: gencb_complete(&read_table_cb->gencb, ret);
49: }
50:
51: static void qed_read_table(BDRVQEDState *s, uint64_t offset, QEDTable *table,
52: BlockDriverCompletionFunc *cb, void *opaque)
53: {
54: QEDReadTableCB *read_table_cb = gencb_alloc(sizeof(*read_table_cb),
55: cb, opaque);
56: QEMUIOVector *qiov = &read_table_cb->qiov;
57: BlockDriverAIOCB *aiocb;
58:
59: trace_qed_read_table(s, offset, table);
60:
61: read_table_cb->s = s;
62: read_table_cb->table = table;
63: read_table_cb->iov.iov_base = table->offsets,
64: read_table_cb->iov.iov_len = s->header.cluster_size * s->header.table_size,
65:
66: qemu_iovec_init_external(qiov, &read_table_cb->iov, 1);
67: aiocb = bdrv_aio_readv(s->bs->file, offset / BDRV_SECTOR_SIZE, qiov,
68: read_table_cb->iov.iov_len / BDRV_SECTOR_SIZE,
69: qed_read_table_cb, read_table_cb);
70: if (!aiocb) {
71: qed_read_table_cb(read_table_cb, -EIO);
72: }
73: }
74:
75: typedef struct {
76: GenericCB gencb;
77: BDRVQEDState *s;
78: QEDTable *orig_table;
79: QEDTable *table;
80: bool flush; /* flush after write? */
81:
82: struct iovec iov;
83: QEMUIOVector qiov;
84: } QEDWriteTableCB;
85:
86: static void qed_write_table_cb(void *opaque, int ret)
87: {
88: QEDWriteTableCB *write_table_cb = opaque;
89:
90: trace_qed_write_table_cb(write_table_cb->s,
91: write_table_cb->orig_table,
92: write_table_cb->flush,
93: ret);
94:
95: if (ret) {
96: goto out;
97: }
98:
99: if (write_table_cb->flush) {
100: /* We still need to flush first */
101: write_table_cb->flush = false;
102: bdrv_aio_flush(write_table_cb->s->bs, qed_write_table_cb,
103: write_table_cb);
104: return;
105: }
106:
107: out:
108: qemu_vfree(write_table_cb->table);
109: gencb_complete(&write_table_cb->gencb, ret);
110: return;
111: }
112:
113: /**
114: * Write out an updated part or all of a table
115: *
116: * @s: QED state
117: * @offset: Offset of table in image file, in bytes
118: * @table: Table
119: * @index: Index of first element
120: * @n: Number of elements
121: * @flush: Whether or not to sync to disk
122: * @cb: Completion function
123: * @opaque: Argument for completion function
124: */
125: static void qed_write_table(BDRVQEDState *s, uint64_t offset, QEDTable *table,
126: unsigned int index, unsigned int n, bool flush,
127: BlockDriverCompletionFunc *cb, void *opaque)
128: {
129: QEDWriteTableCB *write_table_cb;
130: BlockDriverAIOCB *aiocb;
131: unsigned int sector_mask = BDRV_SECTOR_SIZE / sizeof(uint64_t) - 1;
132: unsigned int start, end, i;
133: size_t len_bytes;
134:
135: trace_qed_write_table(s, offset, table, index, n);
136:
137: /* Calculate indices of the first and one after last elements */
138: start = index & ~sector_mask;
139: end = (index + n + sector_mask) & ~sector_mask;
140:
141: len_bytes = (end - start) * sizeof(uint64_t);
142:
143: write_table_cb = gencb_alloc(sizeof(*write_table_cb), cb, opaque);
144: write_table_cb->s = s;
145: write_table_cb->orig_table = table;
146: write_table_cb->flush = flush;
147: write_table_cb->table = qemu_blockalign(s->bs, len_bytes);
148: write_table_cb->iov.iov_base = write_table_cb->table->offsets;
149: write_table_cb->iov.iov_len = len_bytes;
150: qemu_iovec_init_external(&write_table_cb->qiov, &write_table_cb->iov, 1);
151:
152: /* Byteswap table */
153: for (i = start; i < end; i++) {
154: uint64_t le_offset = cpu_to_le64(table->offsets[i]);
155: write_table_cb->table->offsets[i - start] = le_offset;
156: }
157:
158: /* Adjust for offset into table */
159: offset += start * sizeof(uint64_t);
160:
161: aiocb = bdrv_aio_writev(s->bs->file, offset / BDRV_SECTOR_SIZE,
162: &write_table_cb->qiov,
163: write_table_cb->iov.iov_len / BDRV_SECTOR_SIZE,
164: qed_write_table_cb, write_table_cb);
165: if (!aiocb) {
166: qed_write_table_cb(write_table_cb, -EIO);
167: }
168: }
169:
170: /**
171: * Propagate return value from async callback
172: */
173: static void qed_sync_cb(void *opaque, int ret)
174: {
175: *(int *)opaque = ret;
176: }
177:
178: int qed_read_l1_table_sync(BDRVQEDState *s)
179: {
180: int ret = -EINPROGRESS;
181:
182: async_context_push();
183:
184: qed_read_table(s, s->header.l1_table_offset,
185: s->l1_table, qed_sync_cb, &ret);
186: while (ret == -EINPROGRESS) {
187: qemu_aio_wait();
188: }
189:
190: async_context_pop();
191:
192: return ret;
193: }
194:
195: void qed_write_l1_table(BDRVQEDState *s, unsigned int index, unsigned int n,
196: BlockDriverCompletionFunc *cb, void *opaque)
197: {
198: BLKDBG_EVENT(s->bs->file, BLKDBG_L1_UPDATE);
199: qed_write_table(s, s->header.l1_table_offset,
200: s->l1_table, index, n, false, cb, opaque);
201: }
202:
203: int qed_write_l1_table_sync(BDRVQEDState *s, unsigned int index,
204: unsigned int n)
205: {
206: int ret = -EINPROGRESS;
207:
208: async_context_push();
209:
210: qed_write_l1_table(s, index, n, qed_sync_cb, &ret);
211: while (ret == -EINPROGRESS) {
212: qemu_aio_wait();
213: }
214:
215: async_context_pop();
216:
217: return ret;
218: }
219:
220: typedef struct {
221: GenericCB gencb;
222: BDRVQEDState *s;
223: uint64_t l2_offset;
224: QEDRequest *request;
225: } QEDReadL2TableCB;
226:
227: static void qed_read_l2_table_cb(void *opaque, int ret)
228: {
229: QEDReadL2TableCB *read_l2_table_cb = opaque;
230: QEDRequest *request = read_l2_table_cb->request;
231: BDRVQEDState *s = read_l2_table_cb->s;
232: CachedL2Table *l2_table = request->l2_table;
233:
234: if (ret) {
235: /* can't trust loaded L2 table anymore */
236: qed_unref_l2_cache_entry(l2_table);
237: request->l2_table = NULL;
238: } else {
239: l2_table->offset = read_l2_table_cb->l2_offset;
240:
241: qed_commit_l2_cache_entry(&s->l2_cache, l2_table);
242:
243: /* This is guaranteed to succeed because we just committed the entry
244: * to the cache.
245: */
246: request->l2_table = qed_find_l2_cache_entry(&s->l2_cache,
247: l2_table->offset);
248: assert(request->l2_table != NULL);
249: }
250:
251: gencb_complete(&read_l2_table_cb->gencb, ret);
252: }
253:
254: void qed_read_l2_table(BDRVQEDState *s, QEDRequest *request, uint64_t offset,
255: BlockDriverCompletionFunc *cb, void *opaque)
256: {
257: QEDReadL2TableCB *read_l2_table_cb;
258:
259: qed_unref_l2_cache_entry(request->l2_table);
260:
261: /* Check for cached L2 entry */
262: request->l2_table = qed_find_l2_cache_entry(&s->l2_cache, offset);
263: if (request->l2_table) {
264: cb(opaque, 0);
265: return;
266: }
267:
268: request->l2_table = qed_alloc_l2_cache_entry(&s->l2_cache);
269: request->l2_table->table = qed_alloc_table(s);
270:
271: read_l2_table_cb = gencb_alloc(sizeof(*read_l2_table_cb), cb, opaque);
272: read_l2_table_cb->s = s;
273: read_l2_table_cb->l2_offset = offset;
274: read_l2_table_cb->request = request;
275:
276: BLKDBG_EVENT(s->bs->file, BLKDBG_L2_LOAD);
277: qed_read_table(s, offset, request->l2_table->table,
278: qed_read_l2_table_cb, read_l2_table_cb);
279: }
280:
281: int qed_read_l2_table_sync(BDRVQEDState *s, QEDRequest *request, uint64_t offset)
282: {
283: int ret = -EINPROGRESS;
284:
285: async_context_push();
286:
287: qed_read_l2_table(s, request, offset, qed_sync_cb, &ret);
288: while (ret == -EINPROGRESS) {
289: qemu_aio_wait();
290: }
291:
292: async_context_pop();
293: return ret;
294: }
295:
296: void qed_write_l2_table(BDRVQEDState *s, QEDRequest *request,
297: unsigned int index, unsigned int n, bool flush,
298: BlockDriverCompletionFunc *cb, void *opaque)
299: {
300: BLKDBG_EVENT(s->bs->file, BLKDBG_L2_UPDATE);
301: qed_write_table(s, request->l2_table->offset,
302: request->l2_table->table, index, n, flush, cb, opaque);
303: }
304:
305: int qed_write_l2_table_sync(BDRVQEDState *s, QEDRequest *request,
306: unsigned int index, unsigned int n, bool flush)
307: {
308: int ret = -EINPROGRESS;
309:
310: async_context_push();
311:
312: qed_write_l2_table(s, request, index, n, flush, qed_sync_cb, &ret);
313: while (ret == -EINPROGRESS) {
314: qemu_aio_wait();
315: }
316:
317: async_context_pop();
318: return ret;
319: }
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