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