sys/vfs/hammer/hammer_redo.c

   1 /*
   2  * Copyright (c) 2010 The DragonFly Project.  All rights reserved.
   3  *
   4  * This code is derived from software contributed to The DragonFly Project
   5  * by Matthew Dillon <dillon@backplane.com>
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  *
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in
  15  *    the documentation and/or other materials provided with the
  16  *    distribution.
  17  * 3. Neither the name of The DragonFly Project nor the names of its
  18  *    contributors may be used to endorse or promote products derived
  19  *    from this software without specific, prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  22  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  23  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  24  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
  25  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  26  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
  27  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  28  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
  29  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  30  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  31  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  */
  34
  35 /*
  36  * HAMMER redo - REDO record support for the UNDO/REDO FIFO.
  37  *
  38  * See also hammer_undo.c
  39  */
  40
  41 #include "hammer.h"
  42
  43 RB_GENERATE2(hammer_redo_rb_tree, hammer_inode, rb_redonode,
  44              hammer_redo_rb_compare, hammer_off_t, redo_fifo_start);
  45
  46 /*
  47  * HAMMER version 4+ REDO support.
  48  *
  49  * REDO records are used to improve fsync() performance.  Instead of having
  50  * to go through a complete double-flush cycle involving at least two disk
  51  * synchronizations the fsync need only flush UNDO/REDO FIFO buffers through
  52  * the related REDO records, which is a single synchronization requiring
  53  * no track seeking.  If a recovery becomes necessary the recovery code
  54  * will generate logical data writes based on the REDO records encountered.
  55  * That is, the recovery code will UNDO any partial meta-data/data writes
  56  * at the raw disk block level and then REDO the data writes at the logical
  57  * level.
  58  */
  59 int
  60 hammer_generate_redo(hammer_transaction_t trans, hammer_inode_t ip,
  61                      hammer_off_t file_off, uint32_t flags,
  62                      void *base, int len)
  63 {
  64         hammer_mount_t hmp;
  65         hammer_volume_t root_volume;
  66         hammer_blockmap_t undomap;
  67         hammer_buffer_t buffer = NULL;
  68         hammer_fifo_redo_t redo;
  69         hammer_fifo_tail_t tail;
  70         hammer_off_t next_offset;
  71         int error;
  72         int bytes;
  73         int n;
  74
  75         /*
  76          * Setup
  77          */
  78         hmp = trans->hmp;
  79
  80         root_volume = trans->rootvol;
  81         undomap = &hmp->blockmap[HAMMER_ZONE_UNDO_INDEX];
  82
  83         /*
  84          * No undo recursion when modifying the root volume
  85          */
  86         hammer_modify_volume_noundo(NULL, root_volume);
  87         hammer_lock_ex(&hmp->undo_lock);
  88
  89         /* undo had better not roll over (loose test) */
  90         if (hammer_undo_space(trans) < len + HAMMER_BUFSIZE*3)
  91                 hpanic("insufficient UNDO/REDO FIFO space for redo!");
  92
  93         /*
  94          * Loop until the undo for the entire range has been laid down.
  95          * Loop at least once (len might be 0 as a degenerate case).
  96          */
  97         for (;;) {
  98                 /*
  99                  * Fetch the layout offset in the UNDO FIFO, wrap it as
 100                  * necessary.
 101                  */
 102                 if (undomap->next_offset == undomap->alloc_offset)
 103                         undomap->next_offset = HAMMER_ENCODE_UNDO(0);
 104                 next_offset = undomap->next_offset;
 105
 106                 /*
 107                  * This is a tail-chasing FIFO, when we hit the start of a new
 108                  * buffer we don't have to read it in.
 109                  */
 110                 if ((next_offset & HAMMER_BUFMASK) == 0) {
 111                         redo = hammer_bnew(hmp, next_offset, &error, &buffer);
 112                         hammer_format_undo(redo, hmp->undo_seqno ^ 0x40000000);
 113                 } else {
 114                         redo = hammer_bread(hmp, next_offset, &error, &buffer);
 115                 }
 116                 if (error)
 117                         break;
 118                 hammer_modify_buffer_noundo(NULL, buffer);
 119
 120                 /*
 121                  * Calculate how big a media structure fits up to the next
 122                  * alignment point and how large a data payload we can
 123                  * accomodate.
 124                  *
 125                  * If n calculates to 0 or negative there is no room for
 126                  * anything but a PAD.
 127                  */
 128                 bytes = HAMMER_UNDO_ALIGN -
 129                         ((int)next_offset & HAMMER_UNDO_MASK);
 130                 n = bytes -
 131                     (int)sizeof(struct hammer_fifo_redo) -
 132                     (int)sizeof(struct hammer_fifo_tail);
 133
 134                 /*
 135                  * If available space is insufficient for any payload
 136                  * we have to lay down a PAD.
 137                  *
 138                  * The minimum PAD is 8 bytes and the head and tail will
 139                  * overlap each other in that case.  PADs do not have
 140                  * sequence numbers or CRCs.
 141                  *
 142                  * A PAD may not start on a boundary.  That is, every
 143                  * 512-byte block in the UNDO/REDO FIFO must begin with
 144                  * a record containing a sequence number.
 145                  */
 146                 if (n <= 0) {
 147                         KKASSERT(bytes >= sizeof(struct hammer_fifo_tail));
 148                         KKASSERT(((int)next_offset & HAMMER_UNDO_MASK) != 0);
 149                         tail = (void *)((char *)redo + bytes - sizeof(*tail));
 150                         if ((void *)redo != (void *)tail) {
 151                                 tail->tail_signature = HAMMER_TAIL_SIGNATURE;
 152                                 tail->tail_type = HAMMER_HEAD_TYPE_PAD;
 153                                 tail->tail_size = bytes;
 154                         }
 155                         redo->head.hdr_signature = HAMMER_HEAD_SIGNATURE;
 156                         redo->head.hdr_type = HAMMER_HEAD_TYPE_PAD;
 157                         redo->head.hdr_size = bytes;
 158                         /* NO CRC OR SEQ NO */
 159                         undomap->next_offset += bytes;
 160                         hammer_modify_buffer_done(buffer);
 161                         hammer_stats_redo += bytes;
 162                         continue;
 163                 }
 164
 165                 /*
 166                  * When generating an inode-related REDO record we track
 167                  * the point in the UNDO/REDO FIFO containing the inode's
 168                  * earliest REDO record.  See hammer_generate_redo_sync().
 169                  *
 170                  * redo_fifo_next is cleared when an inode is staged to
 171                  * the backend and then used to determine how to reassign
 172                  * redo_fifo_start after the inode flush completes.
 173                  */
 174                 if (ip) {
 175                         redo->redo_objid = ip->obj_id;
 176                         redo->redo_localization = ip->obj_localization;
 177                         if ((ip->flags & HAMMER_INODE_RDIRTY) == 0) {
 178                                 ip->redo_fifo_start = next_offset;
 179                                 if (RB_INSERT(hammer_redo_rb_tree,
 180                                               &hmp->rb_redo_root, ip)) {
 181                                         hpanic("cannot insert inode %p on "
 182                                               "redo FIFO", ip);
 183                                 }
 184                                 ip->flags |= HAMMER_INODE_RDIRTY;
 185                         }
 186                         if (ip->redo_fifo_next == 0)
 187                                 ip->redo_fifo_next = next_offset;
 188                 } else {
 189                         redo->redo_objid = 0;
 190                         redo->redo_localization = 0;
 191                 }
 192
 193                 /*
 194                  * Calculate the actual payload and recalculate the size
 195                  * of the media structure as necessary.  If no data buffer
 196                  * is supplied there is no payload.
 197                  */
 198                 if (base == NULL) {
 199                         n = 0;
 200                 } else if (n > len) {
 201                         n = len;
 202                 }
 203                 bytes = HAMMER_HEAD_DOALIGN(n) +
 204                         (int)sizeof(struct hammer_fifo_redo) +
 205                         (int)sizeof(struct hammer_fifo_tail);
 206                 if (hammer_debug_general & 0x0080) {
 207                         hdkprintf("redo %016jx %d %d\n",
 208                                 (intmax_t)next_offset, bytes, n);
 209                 }
 210
 211                 redo->head.hdr_signature = HAMMER_HEAD_SIGNATURE;
 212                 redo->head.hdr_type = HAMMER_HEAD_TYPE_REDO;
 213                 redo->head.hdr_size = bytes;
 214                 redo->head.hdr_seq = hmp->undo_seqno++;
 215                 redo->head.hdr_crc = 0;
 216                 redo->redo_offset = file_off;
 217                 redo->redo_flags = flags;
 218
 219                 /*
 220                  * Incremental payload.  If no payload we throw the entire
 221                  * len into redo_data_bytes and will not loop.
 222                  */
 223                 if (base) {
 224                         redo->redo_data_bytes = n;
 225                         bcopy(base, redo + 1, n);
 226                         len -= n;
 227                         base = (char *)base + n;
 228                         file_off += n;
 229                 } else {
 230                         redo->redo_data_bytes = len;
 231                         file_off += len;
 232                         len = 0;
 233                 }
 234
 235                 tail = (void *)((char *)redo + bytes - sizeof(*tail));
 236                 tail->tail_signature = HAMMER_TAIL_SIGNATURE;
 237                 tail->tail_type = HAMMER_HEAD_TYPE_REDO;
 238                 tail->tail_size = bytes;
 239
 240                 KKASSERT(bytes >= sizeof(redo->head));
 241                 hammer_crc_set_fifo_head(&redo->head, bytes);
 242                 undomap->next_offset += bytes;
 243                 hammer_stats_redo += bytes;
 244
 245                 /*
 246                  * Before we finish off the buffer we have to deal with any
 247                  * junk between the end of the media structure we just laid
 248                  * down and the UNDO alignment boundary.  We do this by laying
 249                  * down a dummy PAD.  Even though we will probably overwrite
 250                  * it almost immediately we have to do this so recovery runs
 251                  * can iterate the UNDO space without having to depend on
 252                  * the indices in the volume header.
 253                  *
 254                  * This dummy PAD will be overwritten on the next undo so
 255                  * we do not adjust undomap->next_offset.
 256                  */
 257                 bytes = HAMMER_UNDO_ALIGN -
 258                         ((int)undomap->next_offset & HAMMER_UNDO_MASK);
 259                 if (bytes != HAMMER_UNDO_ALIGN) {
 260                         KKASSERT(bytes >= sizeof(struct hammer_fifo_tail));
 261                         redo = (void *)(tail + 1);
 262                         tail = (void *)((char *)redo + bytes - sizeof(*tail));
 263                         if ((void *)redo != (void *)tail) {
 264                                 tail->tail_signature = HAMMER_TAIL_SIGNATURE;
 265                                 tail->tail_type = HAMMER_HEAD_TYPE_PAD;
 266                                 tail->tail_size = bytes;
 267                         }
 268                         redo->head.hdr_signature = HAMMER_HEAD_SIGNATURE;
 269                         redo->head.hdr_type = HAMMER_HEAD_TYPE_PAD;
 270                         redo->head.hdr_size = bytes;
 271                         /* NO CRC OR SEQ NO */
 272                 }
 273                 hammer_modify_buffer_done(buffer);
 274                 if (len == 0)
 275                         break;
 276         }
 277         hammer_modify_volume_done(root_volume);
 278         hammer_unlock(&hmp->undo_lock);
 279
 280         if (buffer)
 281                 hammer_rel_buffer(buffer, 0);
 282
 283         /*
 284          * Make sure the nominal undo span contains at least one REDO_SYNC,
 285          * otherwise the REDO recovery will not be triggered.
 286          */
 287         if ((hmp->flags & HAMMER_MOUNT_REDO_SYNC) == 0 &&
 288             flags != HAMMER_REDO_SYNC) {
 289                 hammer_generate_redo_sync(trans);
 290         }
 291
 292         return(error);
 293 }
 294
 295 /*
 296  * Generate a REDO SYNC record.  At least one such record must be generated
 297  * in the nominal recovery span for the recovery code to be able to run
 298  * REDOs outside of the span.
 299  *
 300  * The SYNC record contains the aggregate earliest UNDO/REDO FIFO offset
 301  * for all inodes with active REDOs.  This changes dynamically as inodes
 302  * get flushed.
 303  *
 304  * During recovery stage2 any new flush cycles must specify the original
 305  * redo sync offset.  That way a crash will re-run the REDOs, at least
 306  * up to the point where the UNDO FIFO does not overwrite the area.
 307  */
 308 void
 309 hammer_generate_redo_sync(hammer_transaction_t trans)
 310 {
 311         hammer_mount_t hmp = trans->hmp;
 312         hammer_inode_t ip;
 313         hammer_off_t redo_fifo_start;
 314
 315         if (hmp->flags & HAMMER_MOUNT_REDO_RECOVERY_RUN) {
 316                 ip = NULL;
 317                 redo_fifo_start = hmp->recover_stage2_offset;
 318         } else {
 319                 ip = RB_FIRST(hammer_redo_rb_tree, &hmp->rb_redo_root);
 320                 if (ip)
 321                         redo_fifo_start = ip->redo_fifo_start;
 322                 else
 323                         redo_fifo_start = 0;
 324         }
 325         if (redo_fifo_start) {
 326                 if (hammer_debug_io & 0x0004) {
 327                         hdkprintf("SYNC IP %p %016jx\n",
 328                                 ip, (intmax_t)redo_fifo_start);
 329                 }
 330                 hammer_generate_redo(trans, NULL, redo_fifo_start,
 331                                      HAMMER_REDO_SYNC, NULL, 0);
 332                 trans->hmp->flags |= HAMMER_MOUNT_REDO_SYNC;
 333         }
 334 }
 335
 336 /*
 337  * This is called when an inode is queued to the backend.
 338  */
 339 void
 340 hammer_redo_fifo_start_flush(hammer_inode_t ip)
 341 {
 342         ip->redo_fifo_next = 0;
 343 }
 344
 345 /*
 346  * This is called when an inode backend flush is finished.  We have to make
 347  * sure that RDIRTY is not set unless dirty bufs are present.  Dirty bufs
 348  * can get destroyed through operations such as truncations and leave
 349  * us with a stale redo_fifo_next.
 350  */
 351 void
 352 hammer_redo_fifo_end_flush(hammer_inode_t ip)
 353 {
 354         hammer_mount_t hmp = ip->hmp;
 355
 356         if (ip->flags & HAMMER_INODE_RDIRTY) {
 357                 RB_REMOVE(hammer_redo_rb_tree, &hmp->rb_redo_root, ip);
 358                 ip->flags &= ~HAMMER_INODE_RDIRTY;
 359         }
 360         if ((ip->flags & HAMMER_INODE_BUFS) == 0)
 361                 ip->redo_fifo_next = 0;
 362         if (ip->redo_fifo_next) {
 363                 ip->redo_fifo_start = ip->redo_fifo_next;
 364                 if (RB_INSERT(hammer_redo_rb_tree, &hmp->rb_redo_root, ip)) {
 365                         hpanic("cannot reinsert inode %p on redo FIFO", ip);
 366                 }
 367                 ip->flags |= HAMMER_INODE_RDIRTY;
 368         }
 369 }