関数 | |
int | rec_free_read (struct tdb_context *tdb, tdb_off_t off, struct list_struct *rec) |
static int | remove_from_freelist (struct tdb_context *tdb, tdb_off_t off, tdb_off_t next) |
static int | update_tailer (struct tdb_context *tdb, tdb_off_t offset, const struct list_struct *rec) |
int | tdb_free (struct tdb_context *tdb, tdb_off_t offset, struct list_struct *rec) |
static tdb_off_t | tdb_allocate_ofs (struct tdb_context *tdb, tdb_len_t length, tdb_off_t rec_ptr, struct list_struct *rec, tdb_off_t last_ptr) |
tdb_off_t | tdb_allocate (struct tdb_context *tdb, tdb_len_t length, struct list_struct *rec) |
int rec_free_read | ( | struct tdb_context * | tdb, | |
tdb_off_t | off, | |||
struct list_struct * | rec | |||
) |
freelist.c の 32 行で定義されています。
参照先 tdb_context::ecode・tdb_context::methods・tdb_context::next・tdb・TDB_DEBUG_WARNING・TDB_ERR_CORRUPT・tdb_methods::tdb_oob・tdb_methods::tdb_read.
参照元 tdb_allocate()・tdb_validate_freelist().
00033 { 00034 if (tdb->methods->tdb_read(tdb, off, rec, sizeof(*rec),DOCONV()) == -1) 00035 return -1; 00036 00037 if (rec->magic == TDB_MAGIC) { 00038 /* this happens when a app is showdown while deleting a record - we should 00039 not completely fail when this happens */ 00040 TDB_LOG((tdb, TDB_DEBUG_WARNING, "rec_free_read non-free magic 0x%x at offset=%d - fixing\n", 00041 rec->magic, off)); 00042 rec->magic = TDB_FREE_MAGIC; 00043 if (tdb->methods->tdb_write(tdb, off, rec, sizeof(*rec)) == -1) 00044 return -1; 00045 } 00046 00047 if (rec->magic != TDB_FREE_MAGIC) { 00048 /* Ensure ecode is set for log fn. */ 00049 tdb->ecode = TDB_ERR_CORRUPT; 00050 TDB_LOG((tdb, TDB_DEBUG_WARNING, "rec_free_read bad magic 0x%x at offset=%d\n", 00051 rec->magic, off)); 00052 return TDB_ERRCODE(TDB_ERR_CORRUPT, -1); 00053 } 00054 if (tdb->methods->tdb_oob(tdb, rec->next+sizeof(*rec), 0) != 0) 00055 return -1; 00056 return 0; 00057 }
static int remove_from_freelist | ( | struct tdb_context * | tdb, | |
tdb_off_t | off, | |||
tdb_off_t | next | |||
) | [static] |
freelist.c の 62 行で定義されています。
参照先 last_ptr・tdb・TDB_DEBUG_FATAL・TDB_ERR_CORRUPT・tdb_ofs_read()・tdb_ofs_write().
参照元 tdb_free().
00063 { 00064 tdb_off_t last_ptr, i; 00065 00066 /* read in the freelist top */ 00067 last_ptr = FREELIST_TOP; 00068 while (tdb_ofs_read(tdb, last_ptr, &i) != -1 && i != 0) { 00069 if (i == off) { 00070 /* We've found it! */ 00071 return tdb_ofs_write(tdb, last_ptr, &next); 00072 } 00073 /* Follow chain (next offset is at start of record) */ 00074 last_ptr = i; 00075 } 00076 TDB_LOG((tdb, TDB_DEBUG_FATAL,"remove_from_freelist: not on list at off=%d\n", off)); 00077 return TDB_ERRCODE(TDB_ERR_CORRUPT, -1); 00078 }
static int update_tailer | ( | struct tdb_context * | tdb, | |
tdb_off_t | offset, | |||
const struct list_struct * | rec | |||
) | [static] |
freelist.c の 82 行で定義されています。
参照先 list_struct::rec_len・tdb・tdb_ofs_write().
参照元 tdb_allocate_ofs()・tdb_free().
00084 { 00085 tdb_off_t totalsize; 00086 00087 /* Offset of tailer from record header */ 00088 totalsize = sizeof(*rec) + rec->rec_len; 00089 return tdb_ofs_write(tdb, offset + totalsize - sizeof(tdb_off_t), 00090 &totalsize); 00091 }
int tdb_free | ( | struct tdb_context * | tdb, | |
tdb_off_t | offset, | |||
struct list_struct * | rec | |||
) |
freelist.c の 95 行で定義されています。
参照先 tdb_header::hash_size・tdb_context::header・tdb_context::map_size・tdb_context::methods・tdb_context::next・list_struct::rec_len・remove_from_freelist()・tdb・TDB_DEBUG_FATAL・tdb_lock()・tdb_ofs_read()・tdb_ofs_write()・tdb_methods::tdb_read・tdb_rec_write()・tdb_unlock()・update_tailer().
参照元 tdb_allocate_ofs()・tdb_do_delete()・tdb_expand()・tdb_recovery_allocate().
00096 { 00097 tdb_off_t right, left; 00098 00099 /* Allocation and tailer lock */ 00100 if (tdb_lock(tdb, -1, F_WRLCK) != 0) 00101 return -1; 00102 00103 /* set an initial tailer, so if we fail we don't leave a bogus record */ 00104 if (update_tailer(tdb, offset, rec) != 0) { 00105 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_free: update_tailer failed!\n")); 00106 goto fail; 00107 } 00108 00109 /* Look right first (I'm an Australian, dammit) */ 00110 right = offset + sizeof(*rec) + rec->rec_len; 00111 if (right + sizeof(*rec) <= tdb->map_size) { 00112 struct list_struct r; 00113 00114 if (tdb->methods->tdb_read(tdb, right, &r, sizeof(r), DOCONV()) == -1) { 00115 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_free: right read failed at %u\n", right)); 00116 goto left; 00117 } 00118 00119 /* If it's free, expand to include it. */ 00120 if (r.magic == TDB_FREE_MAGIC) { 00121 if (remove_from_freelist(tdb, right, r.next) == -1) { 00122 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_free: right free failed at %u\n", right)); 00123 goto left; 00124 } 00125 rec->rec_len += sizeof(r) + r.rec_len; 00126 } 00127 } 00128 00129 left: 00130 /* Look left */ 00131 left = offset - sizeof(tdb_off_t); 00132 if (left > TDB_DATA_START(tdb->header.hash_size)) { 00133 struct list_struct l; 00134 tdb_off_t leftsize; 00135 00136 /* Read in tailer and jump back to header */ 00137 if (tdb_ofs_read(tdb, left, &leftsize) == -1) { 00138 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_free: left offset read failed at %u\n", left)); 00139 goto update; 00140 } 00141 00142 /* it could be uninitialised data */ 00143 if (leftsize == 0 || leftsize == TDB_PAD_U32) { 00144 goto update; 00145 } 00146 00147 left = offset - leftsize; 00148 00149 /* Now read in record */ 00150 if (tdb->methods->tdb_read(tdb, left, &l, sizeof(l), DOCONV()) == -1) { 00151 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_free: left read failed at %u (%u)\n", left, leftsize)); 00152 goto update; 00153 } 00154 00155 /* If it's free, expand to include it. */ 00156 if (l.magic == TDB_FREE_MAGIC) { 00157 if (remove_from_freelist(tdb, left, l.next) == -1) { 00158 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_free: left free failed at %u\n", left)); 00159 goto update; 00160 } else { 00161 offset = left; 00162 rec->rec_len += leftsize; 00163 } 00164 } 00165 } 00166 00167 update: 00168 if (update_tailer(tdb, offset, rec) == -1) { 00169 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_free: update_tailer failed at %u\n", offset)); 00170 goto fail; 00171 } 00172 00173 /* Now, prepend to free list */ 00174 rec->magic = TDB_FREE_MAGIC; 00175 00176 if (tdb_ofs_read(tdb, FREELIST_TOP, &rec->next) == -1 || 00177 tdb_rec_write(tdb, offset, rec) == -1 || 00178 tdb_ofs_write(tdb, FREELIST_TOP, &offset) == -1) { 00179 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_free record write failed at offset=%d\n", offset)); 00180 goto fail; 00181 } 00182 00183 /* And we're done. */ 00184 tdb_unlock(tdb, -1, F_WRLCK); 00185 return 0; 00186 00187 fail: 00188 tdb_unlock(tdb, -1, F_WRLCK); 00189 return -1; 00190 }
static tdb_off_t tdb_allocate_ofs | ( | struct tdb_context * | tdb, | |
tdb_len_t | length, | |||
tdb_off_t | rec_ptr, | |||
struct list_struct * | rec, | |||
tdb_off_t | last_ptr | |||
) | [static] |
freelist.c の 197 行で定義されています。
参照先 list_struct::magic・list_struct::next・list_struct::rec_len・tdb・tdb_free()・tdb_ofs_write()・tdb_rec_write()・update_tailer().
参照元 tdb_allocate().
00199 { 00200 struct list_struct newrec; 00201 tdb_off_t newrec_ptr; 00202 00203 memset(&newrec, '\0', sizeof(newrec)); 00204 00205 /* found it - now possibly split it up */ 00206 if (rec->rec_len > length + MIN_REC_SIZE) { 00207 /* Length of left piece */ 00208 length = TDB_ALIGN(length, TDB_ALIGNMENT); 00209 00210 /* Right piece to go on free list */ 00211 newrec.rec_len = rec->rec_len - (sizeof(*rec) + length); 00212 newrec_ptr = rec_ptr + sizeof(*rec) + length; 00213 00214 /* And left record is shortened */ 00215 rec->rec_len = length; 00216 } else { 00217 newrec_ptr = 0; 00218 } 00219 00220 /* Remove allocated record from the free list */ 00221 if (tdb_ofs_write(tdb, last_ptr, &rec->next) == -1) { 00222 return 0; 00223 } 00224 00225 /* Update header: do this before we drop alloc 00226 lock, otherwise tdb_free() might try to 00227 merge with us, thinking we're free. 00228 (Thanks Jeremy Allison). */ 00229 rec->magic = TDB_MAGIC; 00230 if (tdb_rec_write(tdb, rec_ptr, rec) == -1) { 00231 return 0; 00232 } 00233 00234 /* Did we create new block? */ 00235 if (newrec_ptr) { 00236 /* Update allocated record tailer (we 00237 shortened it). */ 00238 if (update_tailer(tdb, rec_ptr, rec) == -1) { 00239 return 0; 00240 } 00241 00242 /* Free new record */ 00243 if (tdb_free(tdb, newrec_ptr, &newrec) == -1) { 00244 return 0; 00245 } 00246 } 00247 00248 /* all done - return the new record offset */ 00249 return rec_ptr; 00250 }
tdb_off_t tdb_allocate | ( | struct tdb_context * | tdb, | |
tdb_len_t | length, | |||
struct list_struct * | rec | |||
) |
freelist.c の 258 行で定義されています。
参照先 last_ptr・list_struct::next・rec_free_read()・list_struct::rec_len・tdb・tdb_allocate_ofs()・tdb_expand()・tdb_lock()・tdb_ofs_read()・tdb_unlock().
参照元 tdb_store().
00259 { 00260 tdb_off_t rec_ptr, last_ptr, newrec_ptr; 00261 struct { 00262 tdb_off_t rec_ptr, last_ptr; 00263 tdb_len_t rec_len; 00264 } bestfit; 00265 00266 if (tdb_lock(tdb, -1, F_WRLCK) == -1) 00267 return 0; 00268 00269 /* Extra bytes required for tailer */ 00270 length += sizeof(tdb_off_t); 00271 00272 again: 00273 last_ptr = FREELIST_TOP; 00274 00275 /* read in the freelist top */ 00276 if (tdb_ofs_read(tdb, FREELIST_TOP, &rec_ptr) == -1) 00277 goto fail; 00278 00279 bestfit.rec_ptr = 0; 00280 bestfit.last_ptr = 0; 00281 bestfit.rec_len = 0; 00282 00283 /* 00284 this is a best fit allocation strategy. Originally we used 00285 a first fit strategy, but it suffered from massive fragmentation 00286 issues when faced with a slowly increasing record size. 00287 */ 00288 while (rec_ptr) { 00289 if (rec_free_read(tdb, rec_ptr, rec) == -1) { 00290 goto fail; 00291 } 00292 00293 if (rec->rec_len >= length) { 00294 if (bestfit.rec_ptr == 0 || 00295 rec->rec_len < bestfit.rec_len) { 00296 bestfit.rec_len = rec->rec_len; 00297 bestfit.rec_ptr = rec_ptr; 00298 bestfit.last_ptr = last_ptr; 00299 /* consider a fit to be good enough if 00300 we aren't wasting more than half 00301 the space */ 00302 if (bestfit.rec_len < 2*length) { 00303 break; 00304 } 00305 } 00306 } 00307 00308 /* move to the next record */ 00309 last_ptr = rec_ptr; 00310 rec_ptr = rec->next; 00311 } 00312 00313 if (bestfit.rec_ptr != 0) { 00314 if (rec_free_read(tdb, bestfit.rec_ptr, rec) == -1) { 00315 goto fail; 00316 } 00317 00318 newrec_ptr = tdb_allocate_ofs(tdb, length, bestfit.rec_ptr, rec, bestfit.last_ptr); 00319 tdb_unlock(tdb, -1, F_WRLCK); 00320 return newrec_ptr; 00321 } 00322 00323 /* we didn't find enough space. See if we can expand the 00324 database and if we can then try again */ 00325 if (tdb_expand(tdb, length + sizeof(*rec)) == 0) 00326 goto again; 00327 fail: 00328 tdb_unlock(tdb, -1, F_WRLCK); 00329 return 0; 00330 }