block/qed-table.c

   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 "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 }