File:  [Qemu by Fabrice Bellard] / qemu / block-vmdk.c
Revision 1.1.1.6 (vendor branch): download - view: text, annotated - select for diffs
Tue Apr 24 16:50:35 2018 UTC (23 months, 2 weeks ago) by root
Branches: qemu, MAIN
CVS tags: qemu0105, qemu0104, qemu0103, qemu0102, qemu0101, qemu0100, HEAD
qemu 0.10.0

    1: /*
    2:  * Block driver for the VMDK format
    3:  *
    4:  * Copyright (c) 2004 Fabrice Bellard
    5:  * Copyright (c) 2005 Filip Navara
    6:  *
    7:  * Permission is hereby granted, free of charge, to any person obtaining a copy
    8:  * of this software and associated documentation files (the "Software"), to deal
    9:  * in the Software without restriction, including without limitation the rights
   10:  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
   11:  * copies of the Software, and to permit persons to whom the Software is
   12:  * furnished to do so, subject to the following conditions:
   13:  *
   14:  * The above copyright notice and this permission notice shall be included in
   15:  * all copies or substantial portions of the Software.
   16:  *
   17:  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   18:  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   19:  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
   20:  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   21:  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
   22:  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
   23:  * THE SOFTWARE.
   24:  */
   25: 
   26: #include "qemu-common.h"
   27: #include "block_int.h"
   28: 
   29: #define VMDK3_MAGIC (('C' << 24) | ('O' << 16) | ('W' << 8) | 'D')
   30: #define VMDK4_MAGIC (('K' << 24) | ('D' << 16) | ('M' << 8) | 'V')
   31: 
   32: typedef struct {
   33:     uint32_t version;
   34:     uint32_t flags;
   35:     uint32_t disk_sectors;
   36:     uint32_t granularity;
   37:     uint32_t l1dir_offset;
   38:     uint32_t l1dir_size;
   39:     uint32_t file_sectors;
   40:     uint32_t cylinders;
   41:     uint32_t heads;
   42:     uint32_t sectors_per_track;
   43: } VMDK3Header;
   44: 
   45: typedef struct {
   46:     uint32_t version;
   47:     uint32_t flags;
   48:     int64_t capacity;
   49:     int64_t granularity;
   50:     int64_t desc_offset;
   51:     int64_t desc_size;
   52:     int32_t num_gtes_per_gte;
   53:     int64_t rgd_offset;
   54:     int64_t gd_offset;
   55:     int64_t grain_offset;
   56:     char filler[1];
   57:     char check_bytes[4];
   58: } __attribute__((packed)) VMDK4Header;
   59: 
   60: #define L2_CACHE_SIZE 16
   61: 
   62: typedef struct BDRVVmdkState {
   63:     BlockDriverState *hd;
   64:     int64_t l1_table_offset;
   65:     int64_t l1_backup_table_offset;
   66:     uint32_t *l1_table;
   67:     uint32_t *l1_backup_table;
   68:     unsigned int l1_size;
   69:     uint32_t l1_entry_sectors;
   70: 
   71:     unsigned int l2_size;
   72:     uint32_t *l2_cache;
   73:     uint32_t l2_cache_offsets[L2_CACHE_SIZE];
   74:     uint32_t l2_cache_counts[L2_CACHE_SIZE];
   75: 
   76:     unsigned int cluster_sectors;
   77:     uint32_t parent_cid;
   78:     int is_parent;
   79: } BDRVVmdkState;
   80: 
   81: typedef struct VmdkMetaData {
   82:     uint32_t offset;
   83:     unsigned int l1_index;
   84:     unsigned int l2_index;
   85:     unsigned int l2_offset;
   86:     int valid;
   87: } VmdkMetaData;
   88: 
   89: typedef struct ActiveBDRVState{
   90:     BlockDriverState *hd;            // active image handler
   91:     uint64_t cluster_offset;         // current write offset
   92: }ActiveBDRVState;
   93: 
   94: static ActiveBDRVState activeBDRV;
   95: 
   96: 
   97: static int vmdk_probe(const uint8_t *buf, int buf_size, const char *filename)
   98: {
   99:     uint32_t magic;
  100: 
  101:     if (buf_size < 4)
  102:         return 0;
  103:     magic = be32_to_cpu(*(uint32_t *)buf);
  104:     if (magic == VMDK3_MAGIC ||
  105:         magic == VMDK4_MAGIC)
  106:         return 100;
  107:     else
  108:         return 0;
  109: }
  110: 
  111: #define CHECK_CID 1
  112: 
  113: #define SECTOR_SIZE 512
  114: #define DESC_SIZE 20*SECTOR_SIZE	// 20 sectors of 512 bytes each
  115: #define HEADER_SIZE 512   			// first sector of 512 bytes
  116: 
  117: static uint32_t vmdk_read_cid(BlockDriverState *bs, int parent)
  118: {
  119:     BDRVVmdkState *s = bs->opaque;
  120:     char desc[DESC_SIZE];
  121:     uint32_t cid;
  122:     const char *p_name, *cid_str;
  123:     size_t cid_str_size;
  124: 
  125:     /* the descriptor offset = 0x200 */
  126:     if (bdrv_pread(s->hd, 0x200, desc, DESC_SIZE) != DESC_SIZE)
  127:         return 0;
  128: 
  129:     if (parent) {
  130:         cid_str = "parentCID";
  131:         cid_str_size = sizeof("parentCID");
  132:     } else {
  133:         cid_str = "CID";
  134:         cid_str_size = sizeof("CID");
  135:     }
  136: 
  137:     if ((p_name = strstr(desc,cid_str)) != 0) {
  138:         p_name += cid_str_size;
  139:         sscanf(p_name,"%x",&cid);
  140:     }
  141: 
  142:     return cid;
  143: }
  144: 
  145: static int vmdk_write_cid(BlockDriverState *bs, uint32_t cid)
  146: {
  147:     BDRVVmdkState *s = bs->opaque;
  148:     char desc[DESC_SIZE], tmp_desc[DESC_SIZE];
  149:     char *p_name, *tmp_str;
  150: 
  151:     /* the descriptor offset = 0x200 */
  152:     if (bdrv_pread(s->hd, 0x200, desc, DESC_SIZE) != DESC_SIZE)
  153:         return -1;
  154: 
  155:     tmp_str = strstr(desc,"parentCID");
  156:     pstrcpy(tmp_desc, sizeof(tmp_desc), tmp_str);
  157:     if ((p_name = strstr(desc,"CID")) != 0) {
  158:         p_name += sizeof("CID");
  159:         snprintf(p_name, sizeof(desc) - (p_name - desc), "%x\n", cid);
  160:         pstrcat(desc, sizeof(desc), tmp_desc);
  161:     }
  162: 
  163:     if (bdrv_pwrite(s->hd, 0x200, desc, DESC_SIZE) != DESC_SIZE)
  164:         return -1;
  165:     return 0;
  166: }
  167: 
  168: static int vmdk_is_cid_valid(BlockDriverState *bs)
  169: {
  170: #ifdef CHECK_CID
  171:     BDRVVmdkState *s = bs->opaque;
  172:     BlockDriverState *p_bs = s->hd->backing_hd;
  173:     uint32_t cur_pcid;
  174: 
  175:     if (p_bs) {
  176:         cur_pcid = vmdk_read_cid(p_bs,0);
  177:         if (s->parent_cid != cur_pcid)
  178:             // CID not valid
  179:             return 0;
  180:     }
  181: #endif
  182:     // CID valid
  183:     return 1;
  184: }
  185: 
  186: static int vmdk_snapshot_create(const char *filename, const char *backing_file)
  187: {
  188:     int snp_fd, p_fd;
  189:     uint32_t p_cid;
  190:     char *p_name, *gd_buf, *rgd_buf;
  191:     const char *real_filename, *temp_str;
  192:     VMDK4Header header;
  193:     uint32_t gde_entries, gd_size;
  194:     int64_t gd_offset, rgd_offset, capacity, gt_size;
  195:     char p_desc[DESC_SIZE], s_desc[DESC_SIZE], hdr[HEADER_SIZE];
  196:     static const char desc_template[] =
  197:     "# Disk DescriptorFile\n"
  198:     "version=1\n"
  199:     "CID=%x\n"
  200:     "parentCID=%x\n"
  201:     "createType=\"monolithicSparse\"\n"
  202:     "parentFileNameHint=\"%s\"\n"
  203:     "\n"
  204:     "# Extent description\n"
  205:     "RW %u SPARSE \"%s\"\n"
  206:     "\n"
  207:     "# The Disk Data Base \n"
  208:     "#DDB\n"
  209:     "\n";
  210: 
  211:     snp_fd = open(filename, O_RDWR | O_CREAT | O_TRUNC | O_BINARY | O_LARGEFILE, 0644);
  212:     if (snp_fd < 0)
  213:         return -1;
  214:     p_fd = open(backing_file, O_RDONLY | O_BINARY | O_LARGEFILE);
  215:     if (p_fd < 0) {
  216:         close(snp_fd);
  217:         return -1;
  218:     }
  219: 
  220:     /* read the header */
  221:     if (lseek(p_fd, 0x0, SEEK_SET) == -1)
  222:         goto fail;
  223:     if (read(p_fd, hdr, HEADER_SIZE) != HEADER_SIZE)
  224:         goto fail;
  225: 
  226:     /* write the header */
  227:     if (lseek(snp_fd, 0x0, SEEK_SET) == -1)
  228:         goto fail;
  229:     if (write(snp_fd, hdr, HEADER_SIZE) == -1)
  230:         goto fail;
  231: 
  232:     memset(&header, 0, sizeof(header));
  233:     memcpy(&header,&hdr[4], sizeof(header)); // skip the VMDK4_MAGIC
  234: 
  235:     ftruncate(snp_fd, header.grain_offset << 9);
  236:     /* the descriptor offset = 0x200 */
  237:     if (lseek(p_fd, 0x200, SEEK_SET) == -1)
  238:         goto fail;
  239:     if (read(p_fd, p_desc, DESC_SIZE) != DESC_SIZE)
  240:         goto fail;
  241: 
  242:     if ((p_name = strstr(p_desc,"CID")) != 0) {
  243:         p_name += sizeof("CID");
  244:         sscanf(p_name,"%x",&p_cid);
  245:     }
  246: 
  247:     real_filename = filename;
  248:     if ((temp_str = strrchr(real_filename, '\\')) != NULL)
  249:         real_filename = temp_str + 1;
  250:     if ((temp_str = strrchr(real_filename, '/')) != NULL)
  251:         real_filename = temp_str + 1;
  252:     if ((temp_str = strrchr(real_filename, ':')) != NULL)
  253:         real_filename = temp_str + 1;
  254: 
  255:     snprintf(s_desc, sizeof(s_desc), desc_template, p_cid, p_cid, backing_file,
  256:              (uint32_t)header.capacity, real_filename);
  257: 
  258:     /* write the descriptor */
  259:     if (lseek(snp_fd, 0x200, SEEK_SET) == -1)
  260:         goto fail;
  261:     if (write(snp_fd, s_desc, strlen(s_desc)) == -1)
  262:         goto fail;
  263: 
  264:     gd_offset = header.gd_offset * SECTOR_SIZE;     // offset of GD table
  265:     rgd_offset = header.rgd_offset * SECTOR_SIZE;   // offset of RGD table
  266:     capacity = header.capacity * SECTOR_SIZE;       // Extent size
  267:     /*
  268:      * Each GDE span 32M disk, means:
  269:      * 512 GTE per GT, each GTE points to grain
  270:      */
  271:     gt_size = (int64_t)header.num_gtes_per_gte * header.granularity * SECTOR_SIZE;
  272:     if (!gt_size)
  273:         goto fail;
  274:     gde_entries = (uint32_t)(capacity / gt_size);  // number of gde/rgde
  275:     gd_size = gde_entries * sizeof(uint32_t);
  276: 
  277:     /* write RGD */
  278:     rgd_buf = qemu_malloc(gd_size);
  279:     if (lseek(p_fd, rgd_offset, SEEK_SET) == -1)
  280:         goto fail_rgd;
  281:     if (read(p_fd, rgd_buf, gd_size) != gd_size)
  282:         goto fail_rgd;
  283:     if (lseek(snp_fd, rgd_offset, SEEK_SET) == -1)
  284:         goto fail_rgd;
  285:     if (write(snp_fd, rgd_buf, gd_size) == -1)
  286:         goto fail_rgd;
  287:     qemu_free(rgd_buf);
  288: 
  289:     /* write GD */
  290:     gd_buf = qemu_malloc(gd_size);
  291:     if (lseek(p_fd, gd_offset, SEEK_SET) == -1)
  292:         goto fail_gd;
  293:     if (read(p_fd, gd_buf, gd_size) != gd_size)
  294:         goto fail_gd;
  295:     if (lseek(snp_fd, gd_offset, SEEK_SET) == -1)
  296:         goto fail_gd;
  297:     if (write(snp_fd, gd_buf, gd_size) == -1)
  298:         goto fail_gd;
  299:     qemu_free(gd_buf);
  300: 
  301:     close(p_fd);
  302:     close(snp_fd);
  303:     return 0;
  304: 
  305:     fail_gd:
  306:     qemu_free(gd_buf);
  307:     fail_rgd:
  308:     qemu_free(rgd_buf);
  309:     fail:
  310:     close(p_fd);
  311:     close(snp_fd);
  312:     return -1;
  313: }
  314: 
  315: static void vmdk_parent_close(BlockDriverState *bs)
  316: {
  317:     if (bs->backing_hd)
  318:         bdrv_close(bs->backing_hd);
  319: }
  320: 
  321: static int parent_open = 0;
  322: static int vmdk_parent_open(BlockDriverState *bs, const char * filename)
  323: {
  324:     BDRVVmdkState *s = bs->opaque;
  325:     char *p_name;
  326:     char desc[DESC_SIZE];
  327:     char parent_img_name[1024];
  328: 
  329:     /* the descriptor offset = 0x200 */
  330:     if (bdrv_pread(s->hd, 0x200, desc, DESC_SIZE) != DESC_SIZE)
  331:         return -1;
  332: 
  333:     if ((p_name = strstr(desc,"parentFileNameHint")) != 0) {
  334:         char *end_name;
  335:         struct stat file_buf;
  336: 
  337:         p_name += sizeof("parentFileNameHint") + 1;
  338:         if ((end_name = strchr(p_name,'\"')) == 0)
  339:             return -1;
  340:         if ((end_name - p_name) > sizeof (s->hd->backing_file) - 1)
  341:             return -1;
  342: 
  343:         pstrcpy(s->hd->backing_file, end_name - p_name + 1, p_name);
  344:         if (stat(s->hd->backing_file, &file_buf) != 0) {
  345:             path_combine(parent_img_name, sizeof(parent_img_name),
  346:                          filename, s->hd->backing_file);
  347:         } else {
  348:             pstrcpy(parent_img_name, sizeof(parent_img_name),
  349:                     s->hd->backing_file);
  350:         }
  351: 
  352:         s->hd->backing_hd = bdrv_new("");
  353:         if (!s->hd->backing_hd) {
  354:             failure:
  355:             bdrv_close(s->hd);
  356:             return -1;
  357:         }
  358:         parent_open = 1;
  359:         if (bdrv_open(s->hd->backing_hd, parent_img_name, BDRV_O_RDONLY) < 0)
  360:             goto failure;
  361:         parent_open = 0;
  362:     }
  363: 
  364:     return 0;
  365: }
  366: 
  367: static int vmdk_open(BlockDriverState *bs, const char *filename, int flags)
  368: {
  369:     BDRVVmdkState *s = bs->opaque;
  370:     uint32_t magic;
  371:     int l1_size, i, ret;
  372: 
  373:     if (parent_open)
  374:         // Parent must be opened as RO.
  375:         flags = BDRV_O_RDONLY;
  376: 
  377:     ret = bdrv_file_open(&s->hd, filename, flags);
  378:     if (ret < 0)
  379:         return ret;
  380:     if (bdrv_pread(s->hd, 0, &magic, sizeof(magic)) != sizeof(magic))
  381:         goto fail;
  382: 
  383:     magic = be32_to_cpu(magic);
  384:     if (magic == VMDK3_MAGIC) {
  385:         VMDK3Header header;
  386: 
  387:         if (bdrv_pread(s->hd, sizeof(magic), &header, sizeof(header)) != sizeof(header))
  388:             goto fail;
  389:         s->cluster_sectors = le32_to_cpu(header.granularity);
  390:         s->l2_size = 1 << 9;
  391:         s->l1_size = 1 << 6;
  392:         bs->total_sectors = le32_to_cpu(header.disk_sectors);
  393:         s->l1_table_offset = le32_to_cpu(header.l1dir_offset) << 9;
  394:         s->l1_backup_table_offset = 0;
  395:         s->l1_entry_sectors = s->l2_size * s->cluster_sectors;
  396:     } else if (magic == VMDK4_MAGIC) {
  397:         VMDK4Header header;
  398: 
  399:         if (bdrv_pread(s->hd, sizeof(magic), &header, sizeof(header)) != sizeof(header))
  400:             goto fail;
  401:         bs->total_sectors = le64_to_cpu(header.capacity);
  402:         s->cluster_sectors = le64_to_cpu(header.granularity);
  403:         s->l2_size = le32_to_cpu(header.num_gtes_per_gte);
  404:         s->l1_entry_sectors = s->l2_size * s->cluster_sectors;
  405:         if (s->l1_entry_sectors <= 0)
  406:             goto fail;
  407:         s->l1_size = (bs->total_sectors + s->l1_entry_sectors - 1)
  408:             / s->l1_entry_sectors;
  409:         s->l1_table_offset = le64_to_cpu(header.rgd_offset) << 9;
  410:         s->l1_backup_table_offset = le64_to_cpu(header.gd_offset) << 9;
  411: 
  412:         if (parent_open)
  413:             s->is_parent = 1;
  414:         else
  415:             s->is_parent = 0;
  416: 
  417:         // try to open parent images, if exist
  418:         if (vmdk_parent_open(bs, filename) != 0)
  419:             goto fail;
  420:         // write the CID once after the image creation
  421:         s->parent_cid = vmdk_read_cid(bs,1);
  422:     } else {
  423:         goto fail;
  424:     }
  425: 
  426:     /* read the L1 table */
  427:     l1_size = s->l1_size * sizeof(uint32_t);
  428:     s->l1_table = qemu_malloc(l1_size);
  429:     if (bdrv_pread(s->hd, s->l1_table_offset, s->l1_table, l1_size) != l1_size)
  430:         goto fail;
  431:     for(i = 0; i < s->l1_size; i++) {
  432:         le32_to_cpus(&s->l1_table[i]);
  433:     }
  434: 
  435:     if (s->l1_backup_table_offset) {
  436:         s->l1_backup_table = qemu_malloc(l1_size);
  437:         if (bdrv_pread(s->hd, s->l1_backup_table_offset, s->l1_backup_table, l1_size) != l1_size)
  438:             goto fail;
  439:         for(i = 0; i < s->l1_size; i++) {
  440:             le32_to_cpus(&s->l1_backup_table[i]);
  441:         }
  442:     }
  443: 
  444:     s->l2_cache = qemu_malloc(s->l2_size * L2_CACHE_SIZE * sizeof(uint32_t));
  445:     return 0;
  446:  fail:
  447:     qemu_free(s->l1_backup_table);
  448:     qemu_free(s->l1_table);
  449:     qemu_free(s->l2_cache);
  450:     bdrv_delete(s->hd);
  451:     return -1;
  452: }
  453: 
  454: static uint64_t get_cluster_offset(BlockDriverState *bs, VmdkMetaData *m_data,
  455:                                    uint64_t offset, int allocate);
  456: 
  457: static int get_whole_cluster(BlockDriverState *bs, uint64_t cluster_offset,
  458:                              uint64_t offset, int allocate)
  459: {
  460:     uint64_t parent_cluster_offset;
  461:     BDRVVmdkState *s = bs->opaque;
  462:     uint8_t  whole_grain[s->cluster_sectors*512];        // 128 sectors * 512 bytes each = grain size 64KB
  463: 
  464:     // we will be here if it's first write on non-exist grain(cluster).
  465:     // try to read from parent image, if exist
  466:     if (s->hd->backing_hd) {
  467:         BDRVVmdkState *ps = s->hd->backing_hd->opaque;
  468: 
  469:         if (!vmdk_is_cid_valid(bs))
  470:             return -1;
  471: 
  472:         parent_cluster_offset = get_cluster_offset(s->hd->backing_hd, NULL, offset, allocate);
  473: 
  474:         if (parent_cluster_offset) {
  475:             BDRVVmdkState *act_s = activeBDRV.hd->opaque;
  476: 
  477:             if (bdrv_pread(ps->hd, parent_cluster_offset, whole_grain, ps->cluster_sectors*512) != ps->cluster_sectors*512)
  478:                 return -1;
  479: 
  480:             //Write grain only into the active image
  481:             if (bdrv_pwrite(act_s->hd, activeBDRV.cluster_offset << 9, whole_grain, sizeof(whole_grain)) != sizeof(whole_grain))
  482:                 return -1;
  483:         }
  484:     }
  485:     return 0;
  486: }
  487: 
  488: static int vmdk_L2update(BlockDriverState *bs, VmdkMetaData *m_data)
  489: {
  490:     BDRVVmdkState *s = bs->opaque;
  491: 
  492:     /* update L2 table */
  493:     if (bdrv_pwrite(s->hd, ((int64_t)m_data->l2_offset * 512) + (m_data->l2_index * sizeof(m_data->offset)),
  494:                     &(m_data->offset), sizeof(m_data->offset)) != sizeof(m_data->offset))
  495:         return -1;
  496:     /* update backup L2 table */
  497:     if (s->l1_backup_table_offset != 0) {
  498:         m_data->l2_offset = s->l1_backup_table[m_data->l1_index];
  499:         if (bdrv_pwrite(s->hd, ((int64_t)m_data->l2_offset * 512) + (m_data->l2_index * sizeof(m_data->offset)),
  500:                         &(m_data->offset), sizeof(m_data->offset)) != sizeof(m_data->offset))
  501:             return -1;
  502:     }
  503: 
  504:     return 0;
  505: }
  506: 
  507: static uint64_t get_cluster_offset(BlockDriverState *bs, VmdkMetaData *m_data,
  508:                                    uint64_t offset, int allocate)
  509: {
  510:     BDRVVmdkState *s = bs->opaque;
  511:     unsigned int l1_index, l2_offset, l2_index;
  512:     int min_index, i, j;
  513:     uint32_t min_count, *l2_table, tmp = 0;
  514:     uint64_t cluster_offset;
  515: 
  516:     if (m_data)
  517:         m_data->valid = 0;
  518: 
  519:     l1_index = (offset >> 9) / s->l1_entry_sectors;
  520:     if (l1_index >= s->l1_size)
  521:         return 0;
  522:     l2_offset = s->l1_table[l1_index];
  523:     if (!l2_offset)
  524:         return 0;
  525:     for(i = 0; i < L2_CACHE_SIZE; i++) {
  526:         if (l2_offset == s->l2_cache_offsets[i]) {
  527:             /* increment the hit count */
  528:             if (++s->l2_cache_counts[i] == 0xffffffff) {
  529:                 for(j = 0; j < L2_CACHE_SIZE; j++) {
  530:                     s->l2_cache_counts[j] >>= 1;
  531:                 }
  532:             }
  533:             l2_table = s->l2_cache + (i * s->l2_size);
  534:             goto found;
  535:         }
  536:     }
  537:     /* not found: load a new entry in the least used one */
  538:     min_index = 0;
  539:     min_count = 0xffffffff;
  540:     for(i = 0; i < L2_CACHE_SIZE; i++) {
  541:         if (s->l2_cache_counts[i] < min_count) {
  542:             min_count = s->l2_cache_counts[i];
  543:             min_index = i;
  544:         }
  545:     }
  546:     l2_table = s->l2_cache + (min_index * s->l2_size);
  547:     if (bdrv_pread(s->hd, (int64_t)l2_offset * 512, l2_table, s->l2_size * sizeof(uint32_t)) !=
  548:                                                                         s->l2_size * sizeof(uint32_t))
  549:         return 0;
  550: 
  551:     s->l2_cache_offsets[min_index] = l2_offset;
  552:     s->l2_cache_counts[min_index] = 1;
  553:  found:
  554:     l2_index = ((offset >> 9) / s->cluster_sectors) % s->l2_size;
  555:     cluster_offset = le32_to_cpu(l2_table[l2_index]);
  556: 
  557:     if (!cluster_offset) {
  558:         if (!allocate)
  559:             return 0;
  560:         // Avoid the L2 tables update for the images that have snapshots.
  561:         if (!s->is_parent) {
  562:             cluster_offset = bdrv_getlength(s->hd);
  563:             bdrv_truncate(s->hd, cluster_offset + (s->cluster_sectors << 9));
  564: 
  565:             cluster_offset >>= 9;
  566:             tmp = cpu_to_le32(cluster_offset);
  567:             l2_table[l2_index] = tmp;
  568:             // Save the active image state
  569:             activeBDRV.cluster_offset = cluster_offset;
  570:             activeBDRV.hd = bs;
  571:         }
  572:         /* First of all we write grain itself, to avoid race condition
  573:          * that may to corrupt the image.
  574:          * This problem may occur because of insufficient space on host disk
  575:          * or inappropriate VM shutdown.
  576:          */
  577:         if (get_whole_cluster(bs, cluster_offset, offset, allocate) == -1)
  578:             return 0;
  579: 
  580:         if (m_data) {
  581:             m_data->offset = tmp;
  582:             m_data->l1_index = l1_index;
  583:             m_data->l2_index = l2_index;
  584:             m_data->l2_offset = l2_offset;
  585:             m_data->valid = 1;
  586:         }
  587:     }
  588:     cluster_offset <<= 9;
  589:     return cluster_offset;
  590: }
  591: 
  592: static int vmdk_is_allocated(BlockDriverState *bs, int64_t sector_num,
  593:                              int nb_sectors, int *pnum)
  594: {
  595:     BDRVVmdkState *s = bs->opaque;
  596:     int index_in_cluster, n;
  597:     uint64_t cluster_offset;
  598: 
  599:     cluster_offset = get_cluster_offset(bs, NULL, sector_num << 9, 0);
  600:     index_in_cluster = sector_num % s->cluster_sectors;
  601:     n = s->cluster_sectors - index_in_cluster;
  602:     if (n > nb_sectors)
  603:         n = nb_sectors;
  604:     *pnum = n;
  605:     return (cluster_offset != 0);
  606: }
  607: 
  608: static int vmdk_read(BlockDriverState *bs, int64_t sector_num,
  609:                     uint8_t *buf, int nb_sectors)
  610: {
  611:     BDRVVmdkState *s = bs->opaque;
  612:     int index_in_cluster, n, ret;
  613:     uint64_t cluster_offset;
  614: 
  615:     while (nb_sectors > 0) {
  616:         cluster_offset = get_cluster_offset(bs, NULL, sector_num << 9, 0);
  617:         index_in_cluster = sector_num % s->cluster_sectors;
  618:         n = s->cluster_sectors - index_in_cluster;
  619:         if (n > nb_sectors)
  620:             n = nb_sectors;
  621:         if (!cluster_offset) {
  622:             // try to read from parent image, if exist
  623:             if (s->hd->backing_hd) {
  624:                 if (!vmdk_is_cid_valid(bs))
  625:                     return -1;
  626:                 ret = bdrv_read(s->hd->backing_hd, sector_num, buf, n);
  627:                 if (ret < 0)
  628:                     return -1;
  629:             } else {
  630:                 memset(buf, 0, 512 * n);
  631:             }
  632:         } else {
  633:             if(bdrv_pread(s->hd, cluster_offset + index_in_cluster * 512, buf, n * 512) != n * 512)
  634:                 return -1;
  635:         }
  636:         nb_sectors -= n;
  637:         sector_num += n;
  638:         buf += n * 512;
  639:     }
  640:     return 0;
  641: }
  642: 
  643: static int vmdk_write(BlockDriverState *bs, int64_t sector_num,
  644:                      const uint8_t *buf, int nb_sectors)
  645: {
  646:     BDRVVmdkState *s = bs->opaque;
  647:     VmdkMetaData m_data;
  648:     int index_in_cluster, n;
  649:     uint64_t cluster_offset;
  650:     static int cid_update = 0;
  651: 
  652:     if (sector_num > bs->total_sectors) {
  653:         fprintf(stderr,
  654:                 "(VMDK) Wrong offset: sector_num=0x%" PRIx64
  655:                 " total_sectors=0x%" PRIx64 "\n",
  656:                 sector_num, bs->total_sectors);
  657:         return -1;
  658:     }
  659: 
  660:     while (nb_sectors > 0) {
  661:         index_in_cluster = sector_num & (s->cluster_sectors - 1);
  662:         n = s->cluster_sectors - index_in_cluster;
  663:         if (n > nb_sectors)
  664:             n = nb_sectors;
  665:         cluster_offset = get_cluster_offset(bs, &m_data, sector_num << 9, 1);
  666:         if (!cluster_offset)
  667:             return -1;
  668: 
  669:         if (bdrv_pwrite(s->hd, cluster_offset + index_in_cluster * 512, buf, n * 512) != n * 512)
  670:             return -1;
  671:         if (m_data.valid) {
  672:             /* update L2 tables */
  673:             if (vmdk_L2update(bs, &m_data) == -1)
  674:                 return -1;
  675:         }
  676:         nb_sectors -= n;
  677:         sector_num += n;
  678:         buf += n * 512;
  679: 
  680:         // update CID on the first write every time the virtual disk is opened
  681:         if (!cid_update) {
  682:             vmdk_write_cid(bs, time(NULL));
  683:             cid_update++;
  684:         }
  685:     }
  686:     return 0;
  687: }
  688: 
  689: static int vmdk_create(const char *filename, int64_t total_size,
  690:                        const char *backing_file, int flags)
  691: {
  692:     int fd, i;
  693:     VMDK4Header header;
  694:     uint32_t tmp, magic, grains, gd_size, gt_size, gt_count;
  695:     static const char desc_template[] =
  696:         "# Disk DescriptorFile\n"
  697:         "version=1\n"
  698:         "CID=%x\n"
  699:         "parentCID=ffffffff\n"
  700:         "createType=\"monolithicSparse\"\n"
  701:         "\n"
  702:         "# Extent description\n"
  703:         "RW %" PRId64 " SPARSE \"%s\"\n"
  704:         "\n"
  705:         "# The Disk Data Base \n"
  706:         "#DDB\n"
  707:         "\n"
  708:         "ddb.virtualHWVersion = \"%d\"\n"
  709:         "ddb.geometry.cylinders = \"%" PRId64 "\"\n"
  710:         "ddb.geometry.heads = \"16\"\n"
  711:         "ddb.geometry.sectors = \"63\"\n"
  712:         "ddb.adapterType = \"ide\"\n";
  713:     char desc[1024];
  714:     const char *real_filename, *temp_str;
  715: 
  716:     /* XXX: add support for backing file */
  717:     if (backing_file) {
  718:         return vmdk_snapshot_create(filename, backing_file);
  719:     }
  720: 
  721:     fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY | O_LARGEFILE,
  722:               0644);
  723:     if (fd < 0)
  724:         return -1;
  725:     magic = cpu_to_be32(VMDK4_MAGIC);
  726:     memset(&header, 0, sizeof(header));
  727:     header.version = cpu_to_le32(1);
  728:     header.flags = cpu_to_le32(3); /* ?? */
  729:     header.capacity = cpu_to_le64(total_size);
  730:     header.granularity = cpu_to_le64(128);
  731:     header.num_gtes_per_gte = cpu_to_le32(512);
  732: 
  733:     grains = (total_size + header.granularity - 1) / header.granularity;
  734:     gt_size = ((header.num_gtes_per_gte * sizeof(uint32_t)) + 511) >> 9;
  735:     gt_count = (grains + header.num_gtes_per_gte - 1) / header.num_gtes_per_gte;
  736:     gd_size = (gt_count * sizeof(uint32_t) + 511) >> 9;
  737: 
  738:     header.desc_offset = 1;
  739:     header.desc_size = 20;
  740:     header.rgd_offset = header.desc_offset + header.desc_size;
  741:     header.gd_offset = header.rgd_offset + gd_size + (gt_size * gt_count);
  742:     header.grain_offset =
  743:        ((header.gd_offset + gd_size + (gt_size * gt_count) +
  744:          header.granularity - 1) / header.granularity) *
  745:         header.granularity;
  746: 
  747:     header.desc_offset = cpu_to_le64(header.desc_offset);
  748:     header.desc_size = cpu_to_le64(header.desc_size);
  749:     header.rgd_offset = cpu_to_le64(header.rgd_offset);
  750:     header.gd_offset = cpu_to_le64(header.gd_offset);
  751:     header.grain_offset = cpu_to_le64(header.grain_offset);
  752: 
  753:     header.check_bytes[0] = 0xa;
  754:     header.check_bytes[1] = 0x20;
  755:     header.check_bytes[2] = 0xd;
  756:     header.check_bytes[3] = 0xa;
  757: 
  758:     /* write all the data */
  759:     write(fd, &magic, sizeof(magic));
  760:     write(fd, &header, sizeof(header));
  761: 
  762:     ftruncate(fd, header.grain_offset << 9);
  763: 
  764:     /* write grain directory */
  765:     lseek(fd, le64_to_cpu(header.rgd_offset) << 9, SEEK_SET);
  766:     for (i = 0, tmp = header.rgd_offset + gd_size;
  767:          i < gt_count; i++, tmp += gt_size)
  768:         write(fd, &tmp, sizeof(tmp));
  769: 
  770:     /* write backup grain directory */
  771:     lseek(fd, le64_to_cpu(header.gd_offset) << 9, SEEK_SET);
  772:     for (i = 0, tmp = header.gd_offset + gd_size;
  773:          i < gt_count; i++, tmp += gt_size)
  774:         write(fd, &tmp, sizeof(tmp));
  775: 
  776:     /* compose the descriptor */
  777:     real_filename = filename;
  778:     if ((temp_str = strrchr(real_filename, '\\')) != NULL)
  779:         real_filename = temp_str + 1;
  780:     if ((temp_str = strrchr(real_filename, '/')) != NULL)
  781:         real_filename = temp_str + 1;
  782:     if ((temp_str = strrchr(real_filename, ':')) != NULL)
  783:         real_filename = temp_str + 1;
  784:     snprintf(desc, sizeof(desc), desc_template, (unsigned int)time(NULL),
  785:              total_size, real_filename,
  786:              (flags & BLOCK_FLAG_COMPAT6 ? 6 : 4),
  787:              total_size / (int64_t)(63 * 16));
  788: 
  789:     /* write the descriptor */
  790:     lseek(fd, le64_to_cpu(header.desc_offset) << 9, SEEK_SET);
  791:     write(fd, desc, strlen(desc));
  792: 
  793:     close(fd);
  794:     return 0;
  795: }
  796: 
  797: static void vmdk_close(BlockDriverState *bs)
  798: {
  799:     BDRVVmdkState *s = bs->opaque;
  800: 
  801:     qemu_free(s->l1_table);
  802:     qemu_free(s->l2_cache);
  803:     // try to close parent image, if exist
  804:     vmdk_parent_close(s->hd);
  805:     bdrv_delete(s->hd);
  806: }
  807: 
  808: static void vmdk_flush(BlockDriverState *bs)
  809: {
  810:     BDRVVmdkState *s = bs->opaque;
  811:     bdrv_flush(s->hd);
  812: }
  813: 
  814: BlockDriver bdrv_vmdk = {
  815:     "vmdk",
  816:     sizeof(BDRVVmdkState),
  817:     vmdk_probe,
  818:     vmdk_open,
  819:     vmdk_read,
  820:     vmdk_write,
  821:     vmdk_close,
  822:     vmdk_create,
  823:     vmdk_flush,
  824:     vmdk_is_allocated,
  825: };

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