bluesky/serialize.c

   1 /* Blue Sky: File Systems in the Cloud
   2  *
   3  * Copyright (C) 2009  The Regents of the University of California
   4  * Written by Michael Vrable <mvrable@cs.ucsd.edu>
   5  *
   6  * TODO: Licensing
   7  */
   8
   9 #include <stdint.h>
  10 #include <inttypes.h>
  11 #include <glib.h>
  12 #include <string.h>
  13
  14 #include "bluesky.h"
  15
  16 /* Serialization of in-memory filesystem data structures to bytestrings which
  17  * can be written to persistent storage.  All data is stored in little-endian
  18  * format. */
  19
  20 /* Magic signature and structure of serialized superblocks. */
  21
  22 #define SUPERBLOCK_MAGIC 0x65ca91e91b124234ULL
  23
  24 struct serialized_superblock {
  25     uint64_t signature;         /* SUPERBLOCK_MAGIC */
  26     uint64_t next_inum;
  27 } __attribute__((packed));
  28
  29 /* Magic signature for serialized inodes. */
  30
  31 #define INODE_MAGIC 0xa6832100943d71e6ULL
  32
  33 struct serialized_inode {
  34     uint64_t signature;         /* INODE_MAGIC */
  35     int32_t type;
  36     uint32_t mode;
  37     uint32_t uid, gid;
  38     uint32_t nlink;
  39     uint64_t inum;
  40     uint64_t change_count;
  41     int64_t atime;
  42     int64_t ctime;
  43     int64_t mtime;
  44     int64_t ntime;
  45 } __attribute__((packed));
  46
  47 void bluesky_serialize_superblock(GString *out, BlueSkyFS *fs)
  48 {
  49     struct serialized_superblock buf;
  50
  51     buf.signature = GUINT64_TO_LE(SUPERBLOCK_MAGIC);
  52     buf.next_inum = GUINT64_TO_LE(fs->next_inum);
  53
  54     g_string_append_len(out, (gchar *)&buf, sizeof(buf));
  55 }
  56
  57 BlueSkyFS *bluesky_deserialize_superblock(const gchar *buf)
  58 {
  59     struct serialized_superblock *raw = (struct serialized_superblock *)buf;
  60
  61     if (GUINT64_FROM_LE(raw->signature) != SUPERBLOCK_MAGIC)
  62         return NULL;
  63
  64     BlueSkyFS *fs = bluesky_new_fs("deserialized");
  65     fs->next_inum = GUINT64_FROM_LE(raw->next_inum);
  66
  67     return fs;
  68 }
  69
  70 void bluesky_serialize_inode(GString *out, BlueSkyInode *inode)
  71 {
  72     struct serialized_inode buf;
  73
  74     buf.signature = GUINT64_TO_LE(INODE_MAGIC);
  75     buf.type = GUINT32_TO_LE(inode->type);
  76     buf.mode = GUINT32_TO_LE(inode->mode);
  77     buf.uid = GUINT32_TO_LE(inode->uid);
  78     buf.gid = GUINT32_TO_LE(inode->gid);
  79     buf.nlink = GUINT32_TO_LE(inode->nlink);
  80     buf.inum = GUINT64_TO_LE(inode->inum);
  81     buf.change_count = GUINT64_TO_LE(inode->change_count);
  82     buf.atime = GINT64_TO_LE(inode->atime);
  83     buf.ctime = GINT64_TO_LE(inode->ctime);
  84     buf.mtime = GINT64_TO_LE(inode->mtime);
  85     buf.ntime = GINT64_TO_LE(inode->ntime);
  86
  87     g_string_append_len(out, (gchar *)&buf, sizeof(buf));
  88
  89     switch (inode->type) {
  90     case BLUESKY_REGULAR:
  91     {
  92         uint64_t size = GUINT64_TO_LE(inode->size);
  93         g_string_append_len(out, (gchar *)&size, sizeof(uint64_t));
  94         for (int i = 0; i < inode->blocks->len; i++) {
  95             BlueSkyBlock *b = &g_array_index(inode->blocks, BlueSkyBlock, i);
  96             if (b->ref != NULL)
  97                 g_string_append(out, b->ref);
  98             g_string_append_c(out, '\0');
  99         }
 100         break;
 101     }
 102
 103     case BLUESKY_DIRECTORY:
 104     {
 105         uint32_t seq;
 106         uint64_t inum;
 107         GSequenceIter *i = g_sequence_get_begin_iter(inode->dirents);
 108
 109         while (!g_sequence_iter_is_end(i)) {
 110             BlueSkyDirent *d = g_sequence_get(i);
 111
 112             seq = GUINT32_TO_LE(d->cookie);
 113             inum = GUINT64_TO_LE(d->inum);
 114             g_string_append_len(out, (gchar *)&seq, sizeof(uint32_t));
 115             g_string_append_len(out, (gchar *)&inum, sizeof(uint64_t));
 116             g_string_append(out, d->name);
 117             g_string_append_c(out, '\0');
 118
 119             i = g_sequence_iter_next(i);
 120         }
 121
 122         seq = GUINT32_TO_LE(0);
 123         g_string_append_len(out, (gchar *)&seq, sizeof(uint32_t));
 124
 125         break;
 126     }
 127     default:
 128         g_warning("Serialization for inode type %d not implemented!\n",
 129                   inode->type);
 130     }
 131 }
 132
 133 BlueSkyInode *bluesky_deserialize_inode(BlueSkyFS *fs, const gchar *buf)
 134 {
 135     struct serialized_inode *raw = (struct serialized_inode *)buf;
 136
 137     if (GUINT64_FROM_LE(raw->signature) != INODE_MAGIC)
 138         return NULL;
 139
 140     BlueSkyInode *inode = bluesky_new_inode(GUINT64_FROM_LE(raw->inum),
 141                                             fs, GUINT32_FROM_LE(raw->type));
 142
 143     inode->mode = GUINT32_FROM_LE(raw->mode);
 144     inode->uid = GUINT32_FROM_LE(raw->uid);
 145     inode->gid = GUINT32_FROM_LE(raw->gid);
 146     inode->nlink = GUINT32_FROM_LE(raw->nlink);
 147     inode->change_count = GUINT64_FROM_LE(raw->change_count);
 148     inode->atime = GINT64_FROM_LE(raw->atime);
 149     inode->ctime = GINT64_FROM_LE(raw->ctime);
 150     inode->mtime = GINT64_FROM_LE(raw->mtime);
 151     inode->ntime = GINT64_FROM_LE(raw->ntime);
 152
 153     buf += sizeof(struct serialized_inode);
 154
 155     g_print("Deserializing inode %lld...\n", (long long)inode->inum);
 156
 157     /* TODO: Bounds checking */
 158     switch (inode->type) {
 159     case BLUESKY_REGULAR:
 160         inode->size = GINT64_FROM_LE(*(uint64_t *)buf);
 161         buf += sizeof(uint64_t);
 162         g_array_set_size(inode->blocks,
 163                          (inode->size + BLUESKY_BLOCK_SIZE - 1)
 164                           / BLUESKY_BLOCK_SIZE);
 165         for (int i = 0; i < inode->blocks->len; i++) {
 166             BlueSkyBlock *b = &g_array_index(inode->blocks, BlueSkyBlock, i);
 167             b->type = BLUESKY_BLOCK_REF;
 168             b->ref = g_strdup(buf);
 169             buf += strlen(b->ref) + 1;
 170         }
 171         break;
 172
 173     case BLUESKY_DIRECTORY:
 174     {
 175         struct serialized_dirent {
 176             uint32_t seq;
 177             uint64_t inum;
 178             gchar name[0];
 179         } __attribute__((packed));
 180
 181         struct serialized_dirent *d = (struct serialized_dirent *)buf;
 182         while (GUINT32_FROM_LE(d->seq) != 0) {
 183             BlueSkyDirent *dirent = g_new(BlueSkyDirent, 1);
 184             dirent->cookie = GUINT64_FROM_LE(d->seq);
 185             dirent->inum = GUINT64_FROM_LE(d->inum);
 186             dirent->name = g_strdup(d->name);
 187             dirent->name_folded = bluesky_lowercase(d->name);
 188
 189             g_sequence_insert_sorted(inode->dirents, dirent,
 190                                      bluesky_dirent_compare, NULL);
 191             g_hash_table_insert(inode->dirhash, dirent->name, dirent);
 192             g_hash_table_insert(inode->dirhash_folded, dirent->name_folded,
 193                                 dirent);
 194
 195             g_print("  dirent[%08x]: %s -> %"PRIu64"\n",
 196                     dirent->cookie, dirent->name, dirent->inum);
 197
 198             buf = strchr(d->name, '\0') + 1;
 199             d = (struct serialized_dirent *)buf;
 200         }
 201         break;
 202     }
 203     default:
 204         g_warning("Deserialization for inode type %d not implemented!\n",
 205                   inode->type);
 206     }
 207
 208     return inode;
 209 }