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->qiov.size / 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
  58     trace_qed_read_table(s, offset, table);
  59
  60     read_table_cb->s = s;
  61     read_table_cb->table = table;
  62     read_table_cb->iov.iov_base = table->offsets,
  63     read_table_cb->iov.iov_len = s->header.cluster_size * s->header.table_size,
  64
  65     qemu_iovec_init_external(qiov, &read_table_cb->iov, 1);
  66     bdrv_aio_readv(s->bs->file, offset / BDRV_SECTOR_SIZE, qiov,
  67                    qiov->size / BDRV_SECTOR_SIZE,
  68                    qed_read_table_cb, read_table_cb);
  69 }
  70
  71 typedef struct {
  72     GenericCB gencb;
  73     BDRVQEDState *s;
  74     QEDTable *orig_table;
  75     QEDTable *table;
  76     bool flush;             /* flush after write? */
  77
  78     struct iovec iov;
  79     QEMUIOVector qiov;
  80 } QEDWriteTableCB;
  81
  82 static void qed_write_table_cb(void *opaque, int ret)
  83 {
  84     QEDWriteTableCB *write_table_cb = opaque;
  85
  86     trace_qed_write_table_cb(write_table_cb->s,
  87                              write_table_cb->orig_table,
  88                              write_table_cb->flush,
  89                              ret);
  90
  91     if (ret) {
  92         goto out;
  93     }
  94
  95     if (write_table_cb->flush) {
  96         /* We still need to flush first */
  97         write_table_cb->flush = false;
  98         bdrv_aio_flush(write_table_cb->s->bs, qed_write_table_cb,
  99                        write_table_cb);
 100         return;
 101     }
 102
 103 out:
 104     qemu_vfree(write_table_cb->table);
 105     gencb_complete(&write_table_cb->gencb, ret);
 106 }
 107
 108 /**
 109  * Write out an updated part or all of a table
 110  *
 111  * @s:          QED state
 112  * @offset:     Offset of table in image file, in bytes
 113  * @table:      Table
 114  * @index:      Index of first element
 115  * @n:          Number of elements
 116  * @flush:      Whether or not to sync to disk
 117  * @cb:         Completion function
 118  * @opaque:     Argument for completion function
 119  */
 120 static void qed_write_table(BDRVQEDState *s, uint64_t offset, QEDTable *table,
 121                             unsigned int index, unsigned int n, bool flush,
 122                             BlockDriverCompletionFunc *cb, void *opaque)
 123 {
 124     QEDWriteTableCB *write_table_cb;
 125     unsigned int sector_mask = BDRV_SECTOR_SIZE / sizeof(uint64_t) - 1;
 126     unsigned int start, end, i;
 127     size_t len_bytes;
 128
 129     trace_qed_write_table(s, offset, table, index, n);
 130
 131     /* Calculate indices of the first and one after last elements */
 132     start = index & ~sector_mask;
 133     end = (index + n + sector_mask) & ~sector_mask;
 134
 135     len_bytes = (end - start) * sizeof(uint64_t);
 136
 137     write_table_cb = gencb_alloc(sizeof(*write_table_cb), cb, opaque);
 138     write_table_cb->s = s;
 139     write_table_cb->orig_table = table;
 140     write_table_cb->flush = flush;
 141     write_table_cb->table = qemu_blockalign(s->bs, len_bytes);
 142     write_table_cb->iov.iov_base = write_table_cb->table->offsets;
 143     write_table_cb->iov.iov_len = len_bytes;
 144     qemu_iovec_init_external(&write_table_cb->qiov, &write_table_cb->iov, 1);
 145
 146     /* Byteswap table */
 147     for (i = start; i < end; i++) {
 148         uint64_t le_offset = cpu_to_le64(table->offsets[i]);
 149         write_table_cb->table->offsets[i - start] = le_offset;
 150     }
 151
 152     /* Adjust for offset into table */
 153     offset += start * sizeof(uint64_t);
 154
 155     bdrv_aio_writev(s->bs->file, offset / BDRV_SECTOR_SIZE,
 156                     &write_table_cb->qiov,
 157                     write_table_cb->qiov.size / BDRV_SECTOR_SIZE,
 158                     qed_write_table_cb, write_table_cb);
 159 }
 160
 161 /**
 162  * Propagate return value from async callback
 163  */
 164 static void qed_sync_cb(void *opaque, int ret)
 165 {
 166     *(int *)opaque = ret;
 167 }
 168
 169 int qed_read_l1_table_sync(BDRVQEDState *s)
 170 {
 171     int ret = -EINPROGRESS;
 172
 173     qed_read_table(s, s->header.l1_table_offset,
 174                    s->l1_table, qed_sync_cb, &ret);
 175     while (ret == -EINPROGRESS) {
 176         qemu_aio_wait();
 177     }
 178
 179     return ret;
 180 }
 181
 182 void qed_write_l1_table(BDRVQEDState *s, unsigned int index, unsigned int n,
 183                         BlockDriverCompletionFunc *cb, void *opaque)
 184 {
 185     BLKDBG_EVENT(s->bs->file, BLKDBG_L1_UPDATE);
 186     qed_write_table(s, s->header.l1_table_offset,
 187                     s->l1_table, index, n, false, cb, opaque);
 188 }
 189
 190 int qed_write_l1_table_sync(BDRVQEDState *s, unsigned int index,
 191                             unsigned int n)
 192 {
 193     int ret = -EINPROGRESS;
 194
 195     qed_write_l1_table(s, index, n, qed_sync_cb, &ret);
 196     while (ret == -EINPROGRESS) {
 197         qemu_aio_wait();
 198     }
 199
 200     return ret;
 201 }
 202
 203 typedef struct {
 204     GenericCB gencb;
 205     BDRVQEDState *s;
 206     uint64_t l2_offset;
 207     QEDRequest *request;
 208 } QEDReadL2TableCB;
 209
 210 static void qed_read_l2_table_cb(void *opaque, int ret)
 211 {
 212     QEDReadL2TableCB *read_l2_table_cb = opaque;
 213     QEDRequest *request = read_l2_table_cb->request;
 214     BDRVQEDState *s = read_l2_table_cb->s;
 215     CachedL2Table *l2_table = request->l2_table;
 216     uint64_t l2_offset = read_l2_table_cb->l2_offset;
 217
 218     if (ret) {
 219         /* can't trust loaded L2 table anymore */
 220         qed_unref_l2_cache_entry(l2_table);
 221         request->l2_table = NULL;
 222     } else {
 223         l2_table->offset = l2_offset;
 224
 225         qed_commit_l2_cache_entry(&s->l2_cache, l2_table);
 226
 227         /* This is guaranteed to succeed because we just committed the entry
 228          * to the cache.
 229          */
 230         request->l2_table = qed_find_l2_cache_entry(&s->l2_cache, l2_offset);
 231         assert(request->l2_table != NULL);
 232     }
 233
 234     gencb_complete(&read_l2_table_cb->gencb, ret);
 235 }
 236
 237 void qed_read_l2_table(BDRVQEDState *s, QEDRequest *request, uint64_t offset,
 238                        BlockDriverCompletionFunc *cb, void *opaque)
 239 {
 240     QEDReadL2TableCB *read_l2_table_cb;
 241
 242     qed_unref_l2_cache_entry(request->l2_table);
 243
 244     /* Check for cached L2 entry */
 245     request->l2_table = qed_find_l2_cache_entry(&s->l2_cache, offset);
 246     if (request->l2_table) {
 247         cb(opaque, 0);
 248         return;
 249     }
 250
 251     request->l2_table = qed_alloc_l2_cache_entry(&s->l2_cache);
 252     request->l2_table->table = qed_alloc_table(s);
 253
 254     read_l2_table_cb = gencb_alloc(sizeof(*read_l2_table_cb), cb, opaque);
 255     read_l2_table_cb->s = s;
 256     read_l2_table_cb->l2_offset = offset;
 257     read_l2_table_cb->request = request;
 258
 259     BLKDBG_EVENT(s->bs->file, BLKDBG_L2_LOAD);
 260     qed_read_table(s, offset, request->l2_table->table,
 261                    qed_read_l2_table_cb, read_l2_table_cb);
 262 }
 263
 264 int qed_read_l2_table_sync(BDRVQEDState *s, QEDRequest *request, uint64_t offset)
 265 {
 266     int ret = -EINPROGRESS;
 267
 268     qed_read_l2_table(s, request, offset, qed_sync_cb, &ret);
 269     while (ret == -EINPROGRESS) {
 270         qemu_aio_wait();
 271     }
 272
 273     return ret;
 274 }
 275
 276 void qed_write_l2_table(BDRVQEDState *s, QEDRequest *request,
 277                         unsigned int index, unsigned int n, bool flush,
 278                         BlockDriverCompletionFunc *cb, void *opaque)
 279 {
 280     BLKDBG_EVENT(s->bs->file, BLKDBG_L2_UPDATE);
 281     qed_write_table(s, request->l2_table->offset,
 282                     request->l2_table->table, index, n, flush, cb, opaque);
 283 }
 284
 285 int qed_write_l2_table_sync(BDRVQEDState *s, QEDRequest *request,
 286                             unsigned int index, unsigned int n, bool flush)
 287 {
 288     int ret = -EINPROGRESS;
 289
 290     qed_write_l2_table(s, request, index, n, flush, qed_sync_cb, &ret);
 291     while (ret == -EINPROGRESS) {
 292         qemu_aio_wait();
 293     }
 294
 295     return ret;
 296 }