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