| 1 | |
| 2 | * linux/fs/jbd/commit.c
|
| 3 | *
|
| 4 | * Written by Stephen C. Tweedie <[email protected]>, 1998
|
| 5 | *
|
| 6 | * Copyright 1998 Red Hat corp --- All Rights Reserved
|
| 7 | *
|
| 8 | * This file is part of the Linux kernel and is made available under
|
| 9 | * the terms of the GNU General Public License, version 2, or at your
|
| 10 | * option, any later version, incorporated herein by reference.
|
| 11 | *
|
| 12 | * Journal commit routines for the generic filesystem journaling code;
|
| 13 | * part of the ext2fs journaling system.
|
| 14 |
|
| 15 |
|
| 16 | #include <linux/time.h>
|
| 17 | #include <linux/fs.h>
|
| 18 | #include <linux/jbd.h>
|
| 19 | #include <linux/errno.h>
|
| 20 | #include <linux/slab.h>
|
| 21 | #include <linux/mm.h>
|
| 22 | #include <linux/pagemap.h>
|
| 23 | #include <linux/smp_lock.h>
|
| 24 |
|
| 25 | |
| 26 | * Default IO end handler for temporary BJ_IO buffer_heads.
|
| 27 |
|
| 28 | static void journal_end_buffer_io_sync(struct buffer_head *bh, int uptodate)
|
| 29 | {
|
| 30 | BUFFER_TRACE(bh, "");
|
| 31 | if (uptodate)
|
| 32 | set_buffer_uptodate(bh);
|
| 33 | else
|
| 34 | clear_buffer_uptodate(bh);
|
| 35 | unlock_buffer(bh);
|
| 36 | }
|
| 37 |
|
| 38 | |
| 39 | * When an ext3-ordered file is truncated, it is possible that many pages are
|
| 40 | * not sucessfully freed, because they are attached to a committing transaction.
|
| 41 | * After the transaction commits, these pages are left on the LRU, with no
|
| 42 | * ->mapping, and with attached buffers. These pages are trivially reclaimable
|
| 43 | * by the VM, but their apparent absence upsets the VM accounting, and it makes
|
| 44 | * the numbers in /proc/meminfo look odd.
|
| 45 | *
|
| 46 | * So here, we have a buffer which has just come off the forget list. Look to
|
| 47 | * see if we can strip all buffers from the backing page.
|
| 48 | *
|
| 49 | * Called under lock_journal(), and possibly under journal_datalist_lock. The
|
| 50 | * caller provided us with a ref against the buffer, and we drop that here.
|
| 51 |
|
| 52 | static void release_buffer_page(struct buffer_head *bh)
|
| 53 | {
|
| 54 | struct page *page;
|
| 55 |
|
| 56 | if (buffer_dirty(bh))
|
| 57 | goto nope;
|
| 58 | if (atomic_read(&bh->b_count) != 1)
|
| 59 | goto nope;
|
| 60 | page = bh->b_page;
|
| 61 | if (!page)
|
| 62 | goto nope;
|
| 63 | if (page->mapping)
|
| 64 | goto nope;
|
| 65 |
|
| 66 |
|
| 67 | if (TestSetPageLocked(page))
|
| 68 | goto nope;
|
| 69 |
|
| 70 | page_cache_get(page);
|
| 71 | __brelse(bh);
|
| 72 | try_to_free_buffers(page);
|
| 73 | unlock_page(page);
|
| 74 | page_cache_release(page);
|
| 75 | return;
|
| 76 |
|
| 77 | nope:
|
| 78 | __brelse(bh);
|
| 79 | }
|
| 80 |
|
| 81 | |
| 82 | * Try to acquire jbd_lock_bh_state() against the buffer, when j_list_lock is
|
| 83 | * held. For ranking reasons we must trylock. If we lose, schedule away and
|
| 84 | * return 0. j_list_lock is dropped in this case.
|
| 85 |
|
| 86 | static int inverted_lock(journal_t *journal, struct buffer_head *bh)
|
| 87 | {
|
| 88 | if (!jbd_trylock_bh_state(bh)) {
|
| 89 | spin_unlock(&journal->j_list_lock);
|
| 90 | schedule();
|
| 91 | return 0;
|
| 92 | }
|
| 93 | return 1;
|
| 94 | }
|
| 95 |
|
| 96 | |
| 97 | * cleaned up our previous buffers by now, so if we are in abort
|
| 98 | * mode we can now just skip the rest of the journal write
|
| 99 | * entirely.
|
| 100 | *
|
| 101 | * Returns 1 if the journal needs to be aborted or 0 on success
|
| 102 |
|
| 103 | static int journal_write_commit_record(journal_t *journal,
|
| 104 | transaction_t *commit_transaction)
|
| 105 | {
|
| 106 | struct journal_head *descriptor;
|
| 107 | struct buffer_head *bh;
|
| 108 | int i, ret;
|
| 109 | int barrier_done = 0;
|
| 110 |
|
| 111 | if (is_journal_aborted(journal))
|
| 112 | return 0;
|
| 113 |
|
| 114 | descriptor = journal_get_descriptor_buffer(journal);
|
| 115 | if (!descriptor)
|
| 116 | return 1;
|
| 117 |
|
| 118 | bh = jh2bh(descriptor);
|
| 119 |
|
| 120 |
|
| 121 | for (i = 0; i < bh->b_size; i += 512) {
|
| 122 | journal_header_t *tmp = (journal_header_t*)bh->b_data;
|
| 123 | tmp->h_magic = cpu_to_be32(JFS_MAGIC_NUMBER);
|
| 124 | tmp->h_blocktype = cpu_to_be32(JFS_COMMIT_BLOCK);
|
| 125 | tmp->h_sequence = cpu_to_be32(commit_transaction->t_tid);
|
| 126 | }
|
| 127 |
|
| 128 | JBUFFER_TRACE(descriptor, "write commit block");
|
| 129 | set_buffer_dirty(bh);
|
| 130 | if (journal->j_flags & JFS_BARRIER) {
|
| 131 | set_buffer_ordered(bh);
|
| 132 | barrier_done = 1;
|
| 133 | }
|
| 134 | ret = sync_dirty_buffer(bh);
|
| 135 | |
| 136 | * the same time as this one? If so, we don't want to
|
| 137 | * trust the barrier flag in the super, but instead want
|
| 138 | * to remember if we sent a barrier request
|
| 139 |
|
| 140 | if (ret == -EOPNOTSUPP && barrier_done) {
|
| 141 | char b[BDEVNAME_SIZE];
|
| 142 |
|
| 143 | printk(KERN_WARNING
|
| 144 | "JBD: barrier-based sync failed on %s - "
|
| 145 | "disabling barriers\n",
|
| 146 | bdevname(journal->j_dev, b));
|
| 147 | spin_lock(&journal->j_state_lock);
|
| 148 | journal->j_flags &= ~JFS_BARRIER;
|
| 149 | spin_unlock(&journal->j_state_lock);
|
| 150 |
|
| 151 |
|
| 152 | clear_buffer_ordered(bh);
|
| 153 | set_buffer_uptodate(bh);
|
| 154 | set_buffer_dirty(bh);
|
| 155 | ret = sync_dirty_buffer(bh);
|
| 156 | }
|
| 157 | put_bh(bh);
|
| 158 | journal_put_journal_head(descriptor);
|
| 159 |
|
| 160 | return (ret == -EIO);
|
| 161 | }
|
| 162 |
|
| 163 | static void journal_do_submit_data(struct buffer_head **wbuf, int bufs)
|
| 164 | {
|
| 165 | int i;
|
| 166 |
|
| 167 | for (i = 0; i < bufs; i++) {
|
| 168 | wbuf[i]->b_end_io = end_buffer_write_sync;
|
| 169 |
|
| 170 | submit_bh(WRITE, wbuf[i]);
|
| 171 | }
|
| 172 | }
|
| 173 |
|
| 174 | |
| 175 | * Submit all the data buffers to disk
|
| 176 |
|
| 177 | static void journal_submit_data_buffers(journal_t *journal,
|
| 178 | transaction_t *commit_transaction)
|
| 179 | {
|
| 180 | struct journal_head *jh;
|
| 181 | struct buffer_head *bh;
|
| 182 | int locked;
|
| 183 | int bufs = 0;
|
| 184 | struct buffer_head **wbuf = journal->j_wbuf;
|
| 185 |
|
| 186 | |
| 187 | * Whenever we unlock the journal and sleep, things can get added
|
| 188 | * onto ->t_sync_datalist, so we have to keep looping back to
|
| 189 | * write_out_data until we *know* that the list is empty.
|
| 190 | *
|
| 191 | * Cleanup any flushed data buffers from the data list. Even in
|
| 192 | * abort mode, we want to flush this out as soon as possible.
|
| 193 |
|
| 194 | write_out_data:
|
| 195 | cond_resched();
|
| 196 | spin_lock(&journal->j_list_lock);
|
| 197 |
|
| 198 | while (commit_transaction->t_sync_datalist) {
|
| 199 | jh = commit_transaction->t_sync_datalist;
|
| 200 | bh = jh2bh(jh);
|
| 201 | locked = 0;
|
| 202 |
|
| 203 | |
| 204 | * when we are forced to drop various locks
|
| 205 | get_bh(bh);
|
| 206 | |
| 207 | * we need the buffer lock. We try to lock the buffer without
|
| 208 | * blocking. If we fail, we need to drop j_list_lock and do
|
| 209 | * blocking lock_buffer().
|
| 210 |
|
| 211 | if (buffer_dirty(bh)) {
|
| 212 | if (test_set_buffer_locked(bh)) {
|
| 213 | BUFFER_TRACE(bh, "needs blocking lock");
|
| 214 | spin_unlock(&journal->j_list_lock);
|
| 215 |
|
| 216 | journal_do_submit_data(wbuf, bufs);
|
| 217 | bufs = 0;
|
| 218 | lock_buffer(bh);
|
| 219 | spin_lock(&journal->j_list_lock);
|
| 220 | }
|
| 221 | locked = 1;
|
| 222 | }
|
| 223 |
|
| 224 | if (!inverted_lock(journal, bh)) {
|
| 225 | jbd_lock_bh_state(bh);
|
| 226 | spin_lock(&journal->j_list_lock);
|
| 227 | }
|
| 228 |
|
| 229 | if (!buffer_jbd(bh)
|
| 230 | || jh->b_transaction != commit_transaction
|
| 231 | || jh->b_jlist != BJ_SyncData) {
|
| 232 | jbd_unlock_bh_state(bh);
|
| 233 | if (locked)
|
| 234 | unlock_buffer(bh);
|
| 235 | BUFFER_TRACE(bh, "already cleaned up");
|
| 236 | put_bh(bh);
|
| 237 | continue;
|
| 238 | }
|
| 239 | if (locked && test_clear_buffer_dirty(bh)) {
|
| 240 | BUFFER_TRACE(bh, "needs writeout, adding to array");
|
| 241 | wbuf[bufs++] = bh;
|
| 242 | __journal_file_buffer(jh, commit_transaction,
|
| 243 | BJ_Locked);
|
| 244 | jbd_unlock_bh_state(bh);
|
| 245 | if (bufs == journal->j_wbufsize) {
|
| 246 | spin_unlock(&journal->j_list_lock);
|
| 247 | journal_do_submit_data(wbuf, bufs);
|
| 248 | bufs = 0;
|
| 249 | goto write_out_data;
|
| 250 | }
|
| 251 | } else if (!locked && buffer_locked(bh)) {
|
| 252 | __journal_file_buffer(jh, commit_transaction,
|
| 253 | BJ_Locked);
|
| 254 | jbd_unlock_bh_state(bh);
|
| 255 | put_bh(bh);
|
| 256 | } else {
|
| 257 | BUFFER_TRACE(bh, "writeout complete: unfile");
|
| 258 | __journal_unfile_buffer(jh);
|
| 259 | jbd_unlock_bh_state(bh);
|
| 260 | if (locked)
|
| 261 | unlock_buffer(bh);
|
| 262 | journal_remove_journal_head(bh);
|
| 263 | |
| 264 | * journal_remove_journal_head()
|
| 265 | put_bh(bh);
|
| 266 | put_bh(bh);
|
| 267 | }
|
| 268 |
|
| 269 | if (lock_need_resched(&journal->j_list_lock)) {
|
| 270 | spin_unlock(&journal->j_list_lock);
|
| 271 | goto write_out_data;
|
| 272 | }
|
| 273 | }
|
| 274 | spin_unlock(&journal->j_list_lock);
|
| 275 | journal_do_submit_data(wbuf, bufs);
|
| 276 | }
|
| 277 |
|
| 278 | |
| 279 | * journal_commit_transaction
|
| 280 | *
|
| 281 | * The primary function for committing a transaction to the log. This
|
| 282 | * function is called by the journal thread to begin a complete commit.
|
| 283 |
|
| 284 | void journal_commit_transaction(journal_t *journal)
|
| 285 | {
|
| 286 | transaction_t *commit_transaction;
|
| 287 | struct journal_head *jh, *new_jh, *descriptor;
|
| 288 | struct buffer_head **wbuf = journal->j_wbuf;
|
| 289 | int bufs;
|
| 290 | int flags;
|
| 291 | int err;
|
| 292 | unsigned long blocknr;
|
| 293 | char *tagp = NULL;
|
| 294 | journal_header_t *header;
|
| 295 | journal_block_tag_t *tag = NULL;
|
| 296 | int space_left = 0;
|
| 297 | int first_tag = 0;
|
| 298 | int tag_flag;
|
| 299 | int i;
|
| 300 |
|
| 301 | |
| 302 | * First job: lock down the current transaction and wait for
|
| 303 | * all outstanding updates to complete.
|
| 304 |
|
| 305 |
|
| 306 | #ifdef COMMIT_STATS
|
| 307 | spin_lock(&journal->j_list_lock);
|
| 308 | summarise_journal_usage(journal);
|
| 309 | spin_unlock(&journal->j_list_lock);
|
| 310 | #endif
|
| 311 |
|
| 312 |
|
| 313 | if (journal->j_flags & JFS_FLUSHED) {
|
| 314 | jbd_debug(3, "super block updated\n");
|
| 315 | journal_update_superblock(journal, 1);
|
| 316 | } else {
|
| 317 | jbd_debug(3, "superblock not updated\n");
|
| 318 | }
|
| 319 |
|
| 320 | J_ASSERT(journal->j_running_transaction != NULL);
|
| 321 | J_ASSERT(journal->j_committing_transaction == NULL);
|
| 322 |
|
| 323 | commit_transaction = journal->j_running_transaction;
|
| 324 | J_ASSERT(commit_transaction->t_state == T_RUNNING);
|
| 325 |
|
| 326 | jbd_debug(1, "JBD: starting commit of transaction %d\n",
|
| 327 | commit_transaction->t_tid);
|
| 328 |
|
| 329 | spin_lock(&journal->j_state_lock);
|
| 330 | commit_transaction->t_state = T_LOCKED;
|
| 331 |
|
| 332 | spin_lock(&commit_transaction->t_handle_lock);
|
| 333 | while (commit_transaction->t_updates) {
|
| 334 | DEFINE_WAIT(wait);
|
| 335 |
|
| 336 | prepare_to_wait(&journal->j_wait_updates, &wait,
|
| 337 | TASK_UNINTERRUPTIBLE);
|
| 338 | if (commit_transaction->t_updates) {
|
| 339 | spin_unlock(&commit_transaction->t_handle_lock);
|
| 340 | spin_unlock(&journal->j_state_lock);
|
| 341 | schedule();
|
| 342 | spin_lock(&journal->j_state_lock);
|
| 343 | spin_lock(&commit_transaction->t_handle_lock);
|
| 344 | }
|
| 345 | finish_wait(&journal->j_wait_updates, &wait);
|
| 346 | }
|
| 347 | spin_unlock(&commit_transaction->t_handle_lock);
|
| 348 |
|
| 349 | J_ASSERT (commit_transaction->t_outstanding_credits <=
|
| 350 | journal->j_max_transaction_buffers);
|
| 351 |
|
| 352 | |
| 353 | * First thing we are allowed to do is to discard any remaining
|
| 354 | * BJ_Reserved buffers. Note, it is _not_ permissible to assume
|
| 355 | * that there are no such buffers: if a large filesystem
|
| 356 | * operation like a truncate needs to split itself over multiple
|
| 357 | * transactions, then it may try to do a journal_restart() while
|
| 358 | * there are still BJ_Reserved buffers outstanding. These must
|
| 359 | * be released cleanly from the current transaction.
|
| 360 | *
|
| 361 | * In this case, the filesystem must still reserve write access
|
| 362 | * again before modifying the buffer in the new transaction, but
|
| 363 | * we do not require it to remember exactly which old buffers it
|
| 364 | * has reserved. This is consistent with the existing behaviour
|
| 365 | * that multiple journal_get_write_access() calls to the same
|
| 366 | * buffer are perfectly permissable.
|
| 367 |
|
| 368 | while (commit_transaction->t_reserved_list) {
|
| 369 | jh = commit_transaction->t_reserved_list;
|
| 370 | JBUFFER_TRACE(jh, "reserved, unused: refile");
|
| 371 | |
| 372 | * A journal_get_undo_access()+journal_release_buffer() may
|
| 373 | * leave undo-committed data.
|
| 374 |
|
| 375 | if (jh->b_committed_data) {
|
| 376 | struct buffer_head *bh = jh2bh(jh);
|
| 377 |
|
| 378 | jbd_lock_bh_state(bh);
|
| 379 | jbd_slab_free(jh->b_committed_data, bh->b_size);
|
| 380 | jh->b_committed_data = NULL;
|
| 381 | jbd_unlock_bh_state(bh);
|
| 382 | }
|
| 383 | journal_refile_buffer(journal, jh);
|
| 384 | }
|
| 385 |
|
| 386 | |
| 387 | * Now try to drop any written-back buffers from the journal's
|
| 388 | * checkpoint lists. We do this *before* commit because it potentially
|
| 389 | * frees some memory
|
| 390 |
|
| 391 | spin_lock(&journal->j_list_lock);
|
| 392 | __journal_clean_checkpoint_list(journal);
|
| 393 | spin_unlock(&journal->j_list_lock);
|
| 394 |
|
| 395 | jbd_debug (3, "JBD: commit phase 1\n");
|
| 396 |
|
| 397 | |
| 398 | * Switch to a new revoke table.
|
| 399 |
|
| 400 | journal_switch_revoke_table(journal);
|
| 401 |
|
| 402 | commit_transaction->t_state = T_FLUSH;
|
| 403 | journal->j_committing_transaction = commit_transaction;
|
| 404 | journal->j_running_transaction = NULL;
|
| 405 | commit_transaction->t_log_start = journal->j_head;
|
| 406 | wake_up(&journal->j_wait_transaction_locked);
|
| 407 | spin_unlock(&journal->j_state_lock);
|
| 408 |
|
| 409 | jbd_debug (3, "JBD: commit phase 2\n");
|
| 410 |
|
| 411 | |
| 412 | * First, drop modified flag: all accesses to the buffers
|
| 413 | * will be tracked for a new trasaction only -bzzz
|
| 414 |
|
| 415 | spin_lock(&journal->j_list_lock);
|
| 416 | if (commit_transaction->t_buffers) {
|
| 417 | new_jh = jh = commit_transaction->t_buffers->b_tnext;
|
| 418 | do {
|
| 419 | J_ASSERT_JH(new_jh, new_jh->b_modified == 1 ||
|
| 420 | new_jh->b_modified == 0);
|
| 421 | new_jh->b_modified = 0;
|
| 422 | new_jh = new_jh->b_tnext;
|
| 423 | } while (new_jh != jh);
|
| 424 | }
|
| 425 | spin_unlock(&journal->j_list_lock);
|
| 426 |
|
| 427 | |
| 428 | * Now start flushing things to disk, in the order they appear
|
| 429 | * on the transaction lists. Data blocks go first.
|
| 430 |
|
| 431 | err = 0;
|
| 432 | journal_submit_data_buffers(journal, commit_transaction);
|
| 433 |
|
| 434 | |
| 435 | * Wait for all previously submitted IO to complete.
|
| 436 |
|
| 437 | spin_lock(&journal->j_list_lock);
|
| 438 | while (commit_transaction->t_locked_list) {
|
| 439 | struct buffer_head *bh;
|
| 440 |
|
| 441 | jh = commit_transaction->t_locked_list->b_tprev;
|
| 442 | bh = jh2bh(jh);
|
| 443 | get_bh(bh);
|
| 444 | if (buffer_locked(bh)) {
|
| 445 | spin_unlock(&journal->j_list_lock);
|
| 446 | wait_on_buffer(bh);
|
| 447 | if (unlikely(!buffer_uptodate(bh)))
|
| 448 | err = -EIO;
|
| 449 | spin_lock(&journal->j_list_lock);
|
| 450 | }
|
| 451 | if (!inverted_lock(journal, bh)) {
|
| 452 | put_bh(bh);
|
| 453 | spin_lock(&journal->j_list_lock);
|
| 454 | continue;
|
| 455 | }
|
| 456 | if (buffer_jbd(bh) && jh->b_jlist == BJ_Locked) {
|
| 457 | __journal_unfile_buffer(jh);
|
| 458 | jbd_unlock_bh_state(bh);
|
| 459 | journal_remove_journal_head(bh);
|
| 460 | put_bh(bh);
|
| 461 | } else {
|
| 462 | jbd_unlock_bh_state(bh);
|
| 463 | }
|
| 464 | put_bh(bh);
|
| 465 | cond_resched_lock(&journal->j_list_lock);
|
| 466 | }
|
| 467 | spin_unlock(&journal->j_list_lock);
|
| 468 |
|
| 469 | if (err)
|
| 470 | __journal_abort_hard(journal);
|
| 471 |
|
| 472 | journal_write_revoke_records(journal, commit_transaction);
|
| 473 |
|
| 474 | jbd_debug(3, "JBD: commit phase 2\n");
|
| 475 |
|
| 476 | |
| 477 | * If we found any dirty or locked buffers, then we should have
|
| 478 | * looped back up to the write_out_data label. If there weren't
|
| 479 | * any then journal_clean_data_list should have wiped the list
|
| 480 | * clean by now, so check that it is in fact empty.
|
| 481 |
|
| 482 | J_ASSERT (commit_transaction->t_sync_datalist == NULL);
|
| 483 |
|
| 484 | jbd_debug (3, "JBD: commit phase 3\n");
|
| 485 |
|
| 486 | |
| 487 | * Way to go: we have now written out all of the data for a
|
| 488 | * transaction! Now comes the tricky part: we need to write out
|
| 489 | * metadata. Loop over the transaction's entire buffer list:
|
| 490 |
|
| 491 | commit_transaction->t_state = T_COMMIT;
|
| 492 |
|
| 493 | descriptor = NULL;
|
| 494 | bufs = 0;
|
| 495 | while (commit_transaction->t_buffers) {
|
| 496 |
|
| 497 |
|
| 498 |
|
| 499 | jh = commit_transaction->t_buffers;
|
| 500 |
|
| 501 | |
| 502 | release it for background writing.
|
| 503 |
|
| 504 | if (is_journal_aborted(journal)) {
|
| 505 | JBUFFER_TRACE(jh, "journal is aborting: refile");
|
| 506 | journal_refile_buffer(journal, jh);
|
| 507 | |
| 508 | * any descriptor buffers which may have been
|
| 509 | * already allocated, even if we are now
|
| 510 | * aborting.
|
| 511 | if (!commit_transaction->t_buffers)
|
| 512 | goto start_journal_io;
|
| 513 | continue;
|
| 514 | }
|
| 515 |
|
| 516 | |
| 517 | record the metadata buffer.
|
| 518 |
|
| 519 | if (!descriptor) {
|
| 520 | struct buffer_head *bh;
|
| 521 |
|
| 522 | J_ASSERT (bufs == 0);
|
| 523 |
|
| 524 | jbd_debug(4, "JBD: get descriptor\n");
|
| 525 |
|
| 526 | descriptor = journal_get_descriptor_buffer(journal);
|
| 527 | if (!descriptor) {
|
| 528 | __journal_abort_hard(journal);
|
| 529 | continue;
|
| 530 | }
|
| 531 |
|
| 532 | bh = jh2bh(descriptor);
|
| 533 | jbd_debug(4, "JBD: got buffer %llu (%p)\n",
|
| 534 | (unsigned long long)bh->b_blocknr, bh->b_data);
|
| 535 | header = (journal_header_t *)&bh->b_data[0];
|
| 536 | header->h_magic = cpu_to_be32(JFS_MAGIC_NUMBER);
|
| 537 | header->h_blocktype = cpu_to_be32(JFS_DESCRIPTOR_BLOCK);
|
| 538 | header->h_sequence = cpu_to_be32(commit_transaction->t_tid);
|
| 539 |
|
| 540 | tagp = &bh->b_data[sizeof(journal_header_t)];
|
| 541 | space_left = bh->b_size - sizeof(journal_header_t);
|
| 542 | first_tag = 1;
|
| 543 | set_buffer_jwrite(bh);
|
| 544 | set_buffer_dirty(bh);
|
| 545 | wbuf[bufs++] = bh;
|
| 546 |
|
| 547 | |
| 548 | completion later
|
| 549 | BUFFER_TRACE(bh, "ph3: file as descriptor");
|
| 550 | journal_file_buffer(descriptor, commit_transaction,
|
| 551 | BJ_LogCtl);
|
| 552 | }
|
| 553 |
|
| 554 |
|
| 555 |
|
| 556 | err = journal_next_log_block(journal, &blocknr);
|
| 557 | |
| 558 | and repeat this loop: we'll fall into the
|
| 559 | refile-on-abort condition above.
|
| 560 | if (err) {
|
| 561 | __journal_abort_hard(journal);
|
| 562 | continue;
|
| 563 | }
|
| 564 |
|
| 565 | |
| 566 | * start_this_handle() uses t_outstanding_credits to determine
|
| 567 | * the free space in the log, but this counter is changed
|
| 568 | * by journal_next_log_block() also.
|
| 569 |
|
| 570 | commit_transaction->t_outstanding_credits--;
|
| 571 |
|
| 572 | |
| 573 | the shadowed buffer! @@@ This can go if we ever get
|
| 574 | rid of the BJ_IO/BJ_Shadow pairing of buffers.
|
| 575 | atomic_inc(&jh2bh(jh)->b_count);
|
| 576 |
|
| 577 | |
| 578 | (this will requeue both the metadata buffer and the
|
| 579 | temporary IO buffer). new_bh goes on BJ_IO
|
| 580 |
|
| 581 | set_bit(BH_JWrite, &jh2bh(jh)->b_state);
|
| 582 | |
| 583 | * akpm: journal_write_metadata_buffer() sets
|
| 584 | * new_bh->b_transaction to commit_transaction.
|
| 585 | * We need to clean this up before we release new_bh
|
| 586 | * (which is of type BJ_IO)
|
| 587 |
|
| 588 | JBUFFER_TRACE(jh, "ph3: write metadata");
|
| 589 | flags = journal_write_metadata_buffer(commit_transaction,
|
| 590 | jh, &new_jh, blocknr);
|
| 591 | set_bit(BH_JWrite, &jh2bh(new_jh)->b_state);
|
| 592 | wbuf[bufs++] = jh2bh(new_jh);
|
| 593 |
|
| 594 | |
| 595 | buffer
|
| 596 |
|
| 597 | tag_flag = 0;
|
| 598 | if (flags & 1)
|
| 599 | tag_flag |= JFS_FLAG_ESCAPE;
|
| 600 | if (!first_tag)
|
| 601 | tag_flag |= JFS_FLAG_SAME_UUID;
|
| 602 |
|
| 603 | tag = (journal_block_tag_t *) tagp;
|
| 604 | tag->t_blocknr = cpu_to_be32(jh2bh(jh)->b_blocknr);
|
| 605 | tag->t_flags = cpu_to_be32(tag_flag);
|
| 606 | tagp += sizeof(journal_block_tag_t);
|
| 607 | space_left -= sizeof(journal_block_tag_t);
|
| 608 |
|
| 609 | if (first_tag) {
|
| 610 | memcpy (tagp, journal->j_uuid, 16);
|
| 611 | tagp += 16;
|
| 612 | space_left -= 16;
|
| 613 | first_tag = 0;
|
| 614 | }
|
| 615 |
|
| 616 | |
| 617 | let the IO rip!
|
| 618 |
|
| 619 | if (bufs == journal->j_wbufsize ||
|
| 620 | commit_transaction->t_buffers == NULL ||
|
| 621 | space_left < sizeof(journal_block_tag_t) + 16) {
|
| 622 |
|
| 623 | jbd_debug(4, "JBD: Submit %d IOs\n", bufs);
|
| 624 |
|
| 625 | |
| 626 | submitting the IOs. "tag" still points to
|
| 627 | the last tag we set up.
|
| 628 |
|
| 629 | tag->t_flags |= cpu_to_be32(JFS_FLAG_LAST_TAG);
|
| 630 |
|
| 631 | start_journal_io:
|
| 632 | for (i = 0; i < bufs; i++) {
|
| 633 | struct buffer_head *bh = wbuf[i];
|
| 634 | lock_buffer(bh);
|
| 635 | clear_buffer_dirty(bh);
|
| 636 | set_buffer_uptodate(bh);
|
| 637 | bh->b_end_io = journal_end_buffer_io_sync;
|
| 638 | submit_bh(WRITE, bh);
|
| 639 | }
|
| 640 | cond_resched();
|
| 641 |
|
| 642 | |
| 643 | time round the loop.
|
| 644 | descriptor = NULL;
|
| 645 | bufs = 0;
|
| 646 | }
|
| 647 | }
|
| 648 |
|
| 649 | |
| 650 | the log. Before we can commit it, wait for the IO so far to
|
| 651 | complete. Control buffers being written are on the
|
| 652 | transaction's t_log_list queue, and metadata buffers are on
|
| 653 | the t_iobuf_list queue.
|
| 654 |
|
| 655 | Wait for the buffers in reverse order. That way we are
|
| 656 | less likely to be woken up until all IOs have completed, and
|
| 657 | so we incur less scheduling load.
|
| 658 |
|
| 659 |
|
| 660 | jbd_debug(3, "JBD: commit phase 4\n");
|
| 661 |
|
| 662 | |
| 663 | * akpm: these are BJ_IO, and j_list_lock is not needed.
|
| 664 | * See __journal_try_to_free_buffer.
|
| 665 |
|
| 666 | wait_for_iobuf:
|
| 667 | while (commit_transaction->t_iobuf_list != NULL) {
|
| 668 | struct buffer_head *bh;
|
| 669 |
|
| 670 | jh = commit_transaction->t_iobuf_list->b_tprev;
|
| 671 | bh = jh2bh(jh);
|
| 672 | if (buffer_locked(bh)) {
|
| 673 | wait_on_buffer(bh);
|
| 674 | goto wait_for_iobuf;
|
| 675 | }
|
| 676 | if (cond_resched())
|
| 677 | goto wait_for_iobuf;
|
| 678 |
|
| 679 | if (unlikely(!buffer_uptodate(bh)))
|
| 680 | err = -EIO;
|
| 681 |
|
| 682 | clear_buffer_jwrite(bh);
|
| 683 |
|
| 684 | JBUFFER_TRACE(jh, "ph4: unfile after journal write");
|
| 685 | journal_unfile_buffer(journal, jh);
|
| 686 |
|
| 687 | |
| 688 | * ->t_iobuf_list should contain only dummy buffer_heads
|
| 689 | * which were created by journal_write_metadata_buffer().
|
| 690 |
|
| 691 | BUFFER_TRACE(bh, "dumping temporary bh");
|
| 692 | journal_put_journal_head(jh);
|
| 693 | __brelse(bh);
|
| 694 | J_ASSERT_BH(bh, atomic_read(&bh->b_count) == 0);
|
| 695 | free_buffer_head(bh);
|
| 696 |
|
| 697 | |
| 698 | shadowed buffer
|
| 699 | jh = commit_transaction->t_shadow_list->b_tprev;
|
| 700 | bh = jh2bh(jh);
|
| 701 | clear_bit(BH_JWrite, &bh->b_state);
|
| 702 | J_ASSERT_BH(bh, buffer_jbddirty(bh));
|
| 703 |
|
| 704 | |
| 705 | to remember it against this transaction so that when
|
| 706 | we finally commit, we can do any checkpointing
|
| 707 | required.
|
| 708 | JBUFFER_TRACE(jh, "file as BJ_Forget");
|
| 709 | journal_file_buffer(jh, commit_transaction, BJ_Forget);
|
| 710 | |
| 711 | IO to complete
|
| 712 | wake_up_bit(&bh->b_state, BH_Unshadow);
|
| 713 | JBUFFER_TRACE(jh, "brelse shadowed buffer");
|
| 714 | __brelse(bh);
|
| 715 | }
|
| 716 |
|
| 717 | J_ASSERT (commit_transaction->t_shadow_list == NULL);
|
| 718 |
|
| 719 | jbd_debug(3, "JBD: commit phase 5\n");
|
| 720 |
|
| 721 |
|
| 722 | wait_for_ctlbuf:
|
| 723 | while (commit_transaction->t_log_list != NULL) {
|
| 724 | struct buffer_head *bh;
|
| 725 |
|
| 726 | jh = commit_transaction->t_log_list->b_tprev;
|
| 727 | bh = jh2bh(jh);
|
| 728 | if (buffer_locked(bh)) {
|
| 729 | wait_on_buffer(bh);
|
| 730 | goto wait_for_ctlbuf;
|
| 731 | }
|
| 732 | if (cond_resched())
|
| 733 | goto wait_for_ctlbuf;
|
| 734 |
|
| 735 | if (unlikely(!buffer_uptodate(bh)))
|
| 736 | err = -EIO;
|
| 737 |
|
| 738 | BUFFER_TRACE(bh, "ph5: control buffer writeout done: unfile");
|
| 739 | clear_buffer_jwrite(bh);
|
| 740 | journal_unfile_buffer(journal, jh);
|
| 741 | journal_put_journal_head(jh);
|
| 742 | __brelse(bh);
|
| 743 |
|
| 744 | }
|
| 745 |
|
| 746 | jbd_debug(3, "JBD: commit phase 6\n");
|
| 747 |
|
| 748 | if (journal_write_commit_record(journal, commit_transaction))
|
| 749 | err = -EIO;
|
| 750 |
|
| 751 | if (err)
|
| 752 | __journal_abort_hard(journal);
|
| 753 |
|
| 754 | |
| 755 | processing: any buffers committed as a result of this
|
| 756 | transaction can be removed from any checkpoint list it was on
|
| 757 | before.
|
| 758 |
|
| 759 | jbd_debug(3, "JBD: commit phase 7\n");
|
| 760 |
|
| 761 | J_ASSERT(commit_transaction->t_sync_datalist == NULL);
|
| 762 | J_ASSERT(commit_transaction->t_buffers == NULL);
|
| 763 | J_ASSERT(commit_transaction->t_checkpoint_list == NULL);
|
| 764 | J_ASSERT(commit_transaction->t_iobuf_list == NULL);
|
| 765 | J_ASSERT(commit_transaction->t_shadow_list == NULL);
|
| 766 | J_ASSERT(commit_transaction->t_log_list == NULL);
|
| 767 |
|
| 768 | restart_loop:
|
| 769 | |
| 770 | * As there are other places (journal_unmap_buffer()) adding buffers
|
| 771 | * to this list we have to be careful and hold the j_list_lock.
|
| 772 |
|
| 773 | spin_lock(&journal->j_list_lock);
|
| 774 | while (commit_transaction->t_forget) {
|
| 775 | transaction_t *cp_transaction;
|
| 776 | struct buffer_head *bh;
|
| 777 |
|
| 778 | jh = commit_transaction->t_forget;
|
| 779 | spin_unlock(&journal->j_list_lock);
|
| 780 | bh = jh2bh(jh);
|
| 781 | jbd_lock_bh_state(bh);
|
| 782 | J_ASSERT_JH(jh, jh->b_transaction == commit_transaction ||
|
| 783 | jh->b_transaction == journal->j_running_transaction);
|
| 784 |
|
| 785 | |
| 786 | * If there is undo-protected committed data against
|
| 787 | * this buffer, then we can remove it now. If it is a
|
| 788 | * buffer needing such protection, the old frozen_data
|
| 789 | * field now points to a committed version of the
|
| 790 | * buffer, so rotate that field to the new committed
|
| 791 | * data.
|
| 792 | *
|
| 793 | * Otherwise, we can just throw away the frozen data now.
|
| 794 |
|
| 795 | if (jh->b_committed_data) {
|
| 796 | jbd_slab_free(jh->b_committed_data, bh->b_size);
|
| 797 | jh->b_committed_data = NULL;
|
| 798 | if (jh->b_frozen_data) {
|
| 799 | jh->b_committed_data = jh->b_frozen_data;
|
| 800 | jh->b_frozen_data = NULL;
|
| 801 | }
|
| 802 | } else if (jh->b_frozen_data) {
|
| 803 | jbd_slab_free(jh->b_frozen_data, bh->b_size);
|
| 804 | jh->b_frozen_data = NULL;
|
| 805 | }
|
| 806 |
|
| 807 | spin_lock(&journal->j_list_lock);
|
| 808 | cp_transaction = jh->b_cp_transaction;
|
| 809 | if (cp_transaction) {
|
| 810 | JBUFFER_TRACE(jh, "remove from old cp transaction");
|
| 811 | __journal_remove_checkpoint(jh);
|
| 812 | }
|
| 813 |
|
| 814 | |
| 815 | * dirty. If the buffer was added to the BJ_Forget list
|
| 816 | * by journal_forget, it may no longer be dirty and
|
| 817 | * there's no point in keeping a checkpoint record for
|
| 818 | * it.
|
| 819 |
|
| 820 | |
| 821 | * journaled by a previous transaction may end up still
|
| 822 | * being dirty here, but we want to avoid writing back
|
| 823 | * that buffer in the future now that the last use has
|
| 824 | * been committed. That's not only a performance gain,
|
| 825 | * it also stops aliasing problems if the buffer is left
|
| 826 | * behind for writeback and gets reallocated for another
|
| 827 | * use in a different page.
|
| 828 | if (buffer_freed(bh)) {
|
| 829 | clear_buffer_freed(bh);
|
| 830 | clear_buffer_jbddirty(bh);
|
| 831 | }
|
| 832 |
|
| 833 | if (buffer_jbddirty(bh)) {
|
| 834 | JBUFFER_TRACE(jh, "add to new checkpointing trans");
|
| 835 | __journal_insert_checkpoint(jh, commit_transaction);
|
| 836 | JBUFFER_TRACE(jh, "refile for checkpoint writeback");
|
| 837 | __journal_refile_buffer(jh);
|
| 838 | jbd_unlock_bh_state(bh);
|
| 839 | } else {
|
| 840 | J_ASSERT_BH(bh, !buffer_dirty(bh));
|
| 841 | |
| 842 | * it has been freed by this transaction and hence it
|
| 843 | * could not have been reallocated until this
|
| 844 | * transaction has committed. *BUT* it could be
|
| 845 | * reallocated once we have written all the data to
|
| 846 | * disk and before we process the buffer on BJ_Forget
|
| 847 | * list.
|
| 848 | JBUFFER_TRACE(jh, "refile or unfile freed buffer");
|
| 849 | __journal_refile_buffer(jh);
|
| 850 | if (!jh->b_transaction) {
|
| 851 | jbd_unlock_bh_state(bh);
|
| 852 |
|
| 853 | journal_remove_journal_head(bh);
|
| 854 | release_buffer_page(bh);
|
| 855 | } else
|
| 856 | jbd_unlock_bh_state(bh);
|
| 857 | }
|
| 858 | cond_resched_lock(&journal->j_list_lock);
|
| 859 | }
|
| 860 | spin_unlock(&journal->j_list_lock);
|
| 861 | |
| 862 | * This is a bit sleazy. We borrow j_list_lock to protect
|
| 863 | * journal->j_committing_transaction in __journal_remove_checkpoint.
|
| 864 | * Really, __journal_remove_checkpoint should be using j_state_lock but
|
| 865 | * it's a bit hassle to hold that across __journal_remove_checkpoint
|
| 866 |
|
| 867 | spin_lock(&journal->j_state_lock);
|
| 868 | spin_lock(&journal->j_list_lock);
|
| 869 | |
| 870 | * Now recheck if some buffers did not get attached to the transaction
|
| 871 | * while the lock was dropped...
|
| 872 |
|
| 873 | if (commit_transaction->t_forget) {
|
| 874 | spin_unlock(&journal->j_list_lock);
|
| 875 | spin_unlock(&journal->j_state_lock);
|
| 876 | goto restart_loop;
|
| 877 | }
|
| 878 |
|
| 879 |
|
| 880 |
|
| 881 | jbd_debug(3, "JBD: commit phase 8\n");
|
| 882 |
|
| 883 | J_ASSERT(commit_transaction->t_state == T_COMMIT);
|
| 884 |
|
| 885 | commit_transaction->t_state = T_FINISHED;
|
| 886 | J_ASSERT(commit_transaction == journal->j_committing_transaction);
|
| 887 | journal->j_commit_sequence = commit_transaction->t_tid;
|
| 888 | journal->j_committing_transaction = NULL;
|
| 889 | spin_unlock(&journal->j_state_lock);
|
| 890 |
|
| 891 | if (commit_transaction->t_checkpoint_list == NULL) {
|
| 892 | __journal_drop_transaction(journal, commit_transaction);
|
| 893 | } else {
|
| 894 | if (journal->j_checkpoint_transactions == NULL) {
|
| 895 | journal->j_checkpoint_transactions = commit_transaction;
|
| 896 | commit_transaction->t_cpnext = commit_transaction;
|
| 897 | commit_transaction->t_cpprev = commit_transaction;
|
| 898 | } else {
|
| 899 | commit_transaction->t_cpnext =
|
| 900 | journal->j_checkpoint_transactions;
|
| 901 | commit_transaction->t_cpprev =
|
| 902 | commit_transaction->t_cpnext->t_cpprev;
|
| 903 | commit_transaction->t_cpnext->t_cpprev =
|
| 904 | commit_transaction;
|
| 905 | commit_transaction->t_cpprev->t_cpnext =
|
| 906 | commit_transaction;
|
| 907 | }
|
| 908 | }
|
| 909 | spin_unlock(&journal->j_list_lock);
|
| 910 |
|
| 911 | jbd_debug(1, "JBD: commit %d complete, head %d\n",
|
| 912 | journal->j_commit_sequence, journal->j_tail_sequence);
|
| 913 |
|
| 914 | wake_up(&journal->j_wait_done_commit);
|
| 915 | }
|