| 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/mm.h>
|
| 21 | #include <linux/pagemap.h>
|
| 22 | #include <linux/bio.h>
|
| 23 | #include <linux/blkdev.h>
|
| 24 | #include <trace/events/jbd.h>
|
| 25 |
|
| 26 | |
| 27 | * Default IO end handler for temporary BJ_IO buffer_heads.
|
| 28 |
|
| 29 | static void journal_end_buffer_io_sync(struct buffer_head *bh, int uptodate)
|
| 30 | {
|
| 31 | BUFFER_TRACE(bh, "");
|
| 32 | if (uptodate)
|
| 33 | set_buffer_uptodate(bh);
|
| 34 | else
|
| 35 | clear_buffer_uptodate(bh);
|
| 36 | unlock_buffer(bh);
|
| 37 | }
|
| 38 |
|
| 39 | |
| 40 | * When an ext3-ordered file is truncated, it is possible that many pages are
|
| 41 | * not successfully freed, because they are attached to a committing transaction.
|
| 42 | * After the transaction commits, these pages are left on the LRU, with no
|
| 43 | * ->mapping, and with attached buffers. These pages are trivially reclaimable
|
| 44 | * by the VM, but their apparent absence upsets the VM accounting, and it makes
|
| 45 | * the numbers in /proc/meminfo look odd.
|
| 46 | *
|
| 47 | * So here, we have a buffer which has just come off the forget list. Look to
|
| 48 | * see if we can strip all buffers from the backing page.
|
| 49 | *
|
| 50 | * Called under journal->j_list_lock. The caller provided us with a ref
|
| 51 | * against the buffer, and we drop that here.
|
| 52 |
|
| 53 | static void release_buffer_page(struct buffer_head *bh)
|
| 54 | {
|
| 55 | struct page *page;
|
| 56 |
|
| 57 | if (buffer_dirty(bh))
|
| 58 | goto nope;
|
| 59 | if (atomic_read(&bh->b_count) != 1)
|
| 60 | goto nope;
|
| 61 | page = bh->b_page;
|
| 62 | if (!page)
|
| 63 | goto nope;
|
| 64 | if (page->mapping)
|
| 65 | goto nope;
|
| 66 |
|
| 67 |
|
| 68 | if (!trylock_page(page))
|
| 69 | goto nope;
|
| 70 |
|
| 71 | page_cache_get(page);
|
| 72 | __brelse(bh);
|
| 73 | try_to_free_buffers(page);
|
| 74 | unlock_page(page);
|
| 75 | page_cache_release(page);
|
| 76 | return;
|
| 77 |
|
| 78 | nope:
|
| 79 | __brelse(bh);
|
| 80 | }
|
| 81 |
|
| 82 | |
| 83 | * Decrement reference counter for data buffer. If it has been marked
|
| 84 | * 'BH_Freed', release it and the page to which it belongs if possible.
|
| 85 |
|
| 86 | static void release_data_buffer(struct buffer_head *bh)
|
| 87 | {
|
| 88 | if (buffer_freed(bh)) {
|
| 89 | WARN_ON_ONCE(buffer_dirty(bh));
|
| 90 | clear_buffer_freed(bh);
|
| 91 | clear_buffer_mapped(bh);
|
| 92 | clear_buffer_new(bh);
|
| 93 | clear_buffer_req(bh);
|
| 94 | bh->b_bdev = NULL;
|
| 95 | release_buffer_page(bh);
|
| 96 | } else
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| 97 | put_bh(bh);
|
| 98 | }
|
| 99 |
|
| 100 | |
| 101 | * Try to acquire jbd_lock_bh_state() against the buffer, when j_list_lock is
|
| 102 | * held. For ranking reasons we must trylock. If we lose, schedule away and
|
| 103 | * return 0. j_list_lock is dropped in this case.
|
| 104 |
|
| 105 | static int inverted_lock(journal_t *journal, struct buffer_head *bh)
|
| 106 | {
|
| 107 | if (!jbd_trylock_bh_state(bh)) {
|
| 108 | spin_unlock(&journal->j_list_lock);
|
| 109 | schedule();
|
| 110 | return 0;
|
| 111 | }
|
| 112 | return 1;
|
| 113 | }
|
| 114 |
|
| 115 | |
| 116 | * cleaned up our previous buffers by now, so if we are in abort
|
| 117 | * mode we can now just skip the rest of the journal write
|
| 118 | * entirely.
|
| 119 | *
|
| 120 | * Returns 1 if the journal needs to be aborted or 0 on success
|
| 121 |
|
| 122 | static int journal_write_commit_record(journal_t *journal,
|
| 123 | transaction_t *commit_transaction)
|
| 124 | {
|
| 125 | struct journal_head *descriptor;
|
| 126 | struct buffer_head *bh;
|
| 127 | journal_header_t *header;
|
| 128 | int ret;
|
| 129 |
|
| 130 | if (is_journal_aborted(journal))
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| 131 | return 0;
|
| 132 |
|
| 133 | descriptor = journal_get_descriptor_buffer(journal);
|
| 134 | if (!descriptor)
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| 135 | return 1;
|
| 136 |
|
| 137 | bh = jh2bh(descriptor);
|
| 138 |
|
| 139 | header = (journal_header_t *)(bh->b_data);
|
| 140 | header->h_magic = cpu_to_be32(JFS_MAGIC_NUMBER);
|
| 141 | header->h_blocktype = cpu_to_be32(JFS_COMMIT_BLOCK);
|
| 142 | header->h_sequence = cpu_to_be32(commit_transaction->t_tid);
|
| 143 |
|
| 144 | JBUFFER_TRACE(descriptor, "write commit block");
|
| 145 | set_buffer_dirty(bh);
|
| 146 |
|
| 147 | if (journal->j_flags & JFS_BARRIER)
|
| 148 | ret = __sync_dirty_buffer(bh, WRITE_SYNC | WRITE_FLUSH_FUA);
|
| 149 | else
|
| 150 | ret = sync_dirty_buffer(bh);
|
| 151 |
|
| 152 | put_bh(bh);
|
| 153 | journal_put_journal_head(descriptor);
|
| 154 |
|
| 155 | return (ret == -EIO);
|
| 156 | }
|
| 157 |
|
| 158 | static void journal_do_submit_data(struct buffer_head **wbuf, int bufs,
|
| 159 | int write_op)
|
| 160 | {
|
| 161 | int i;
|
| 162 |
|
| 163 | for (i = 0; i < bufs; i++) {
|
| 164 | wbuf[i]->b_end_io = end_buffer_write_sync;
|
| 165 | |
| 166 | * Here we write back pagecache data that may be mmaped. Since
|
| 167 | * we cannot afford to clean the page and set PageWriteback
|
| 168 | * here due to lock ordering (page lock ranks above transaction
|
| 169 | * start), the data can change while IO is in flight. Tell the
|
| 170 | * block layer it should bounce the bio pages if stable data
|
| 171 | * during write is required.
|
| 172 | *
|
| 173 | * We use up our safety reference in submit_bh().
|
| 174 |
|
| 175 | _submit_bh(write_op, wbuf[i], 1 << BIO_SNAP_STABLE);
|
| 176 | }
|
| 177 | }
|
| 178 |
|
| 179 | |
| 180 | * Submit all the data buffers to disk
|
| 181 |
|
| 182 | static int journal_submit_data_buffers(journal_t *journal,
|
| 183 | transaction_t *commit_transaction,
|
| 184 | int write_op)
|
| 185 | {
|
| 186 | struct journal_head *jh;
|
| 187 | struct buffer_head *bh;
|
| 188 | int locked;
|
| 189 | int bufs = 0;
|
| 190 | struct buffer_head **wbuf = journal->j_wbuf;
|
| 191 | int err = 0;
|
| 192 |
|
| 193 | |
| 194 | * Whenever we unlock the journal and sleep, things can get added
|
| 195 | * onto ->t_sync_datalist, so we have to keep looping back to
|
| 196 | * write_out_data until we *know* that the list is empty.
|
| 197 | *
|
| 198 | * Cleanup any flushed data buffers from the data list. Even in
|
| 199 | * abort mode, we want to flush this out as soon as possible.
|
| 200 |
|
| 201 | write_out_data:
|
| 202 | cond_resched();
|
| 203 | spin_lock(&journal->j_list_lock);
|
| 204 |
|
| 205 | while (commit_transaction->t_sync_datalist) {
|
| 206 | jh = commit_transaction->t_sync_datalist;
|
| 207 | bh = jh2bh(jh);
|
| 208 | locked = 0;
|
| 209 |
|
| 210 | |
| 211 | * when we are forced to drop various locks
|
| 212 | get_bh(bh);
|
| 213 | |
| 214 | * we need the buffer lock. We try to lock the buffer without
|
| 215 | * blocking. If we fail, we need to drop j_list_lock and do
|
| 216 | * blocking lock_buffer().
|
| 217 |
|
| 218 | if (buffer_dirty(bh)) {
|
| 219 | if (!trylock_buffer(bh)) {
|
| 220 | BUFFER_TRACE(bh, "needs blocking lock");
|
| 221 | spin_unlock(&journal->j_list_lock);
|
| 222 | trace_jbd_do_submit_data(journal,
|
| 223 | commit_transaction);
|
| 224 |
|
| 225 | journal_do_submit_data(wbuf, bufs, write_op);
|
| 226 | bufs = 0;
|
| 227 | lock_buffer(bh);
|
| 228 | spin_lock(&journal->j_list_lock);
|
| 229 | }
|
| 230 | locked = 1;
|
| 231 | }
|
| 232 |
|
| 233 | if (!inverted_lock(journal, bh)) {
|
| 234 | jbd_lock_bh_state(bh);
|
| 235 | spin_lock(&journal->j_list_lock);
|
| 236 | }
|
| 237 |
|
| 238 | if (!buffer_jbd(bh) || bh2jh(bh) != jh
|
| 239 | || jh->b_transaction != commit_transaction
|
| 240 | || jh->b_jlist != BJ_SyncData) {
|
| 241 | jbd_unlock_bh_state(bh);
|
| 242 | if (locked)
|
| 243 | unlock_buffer(bh);
|
| 244 | BUFFER_TRACE(bh, "already cleaned up");
|
| 245 | release_data_buffer(bh);
|
| 246 | continue;
|
| 247 | }
|
| 248 | if (locked && test_clear_buffer_dirty(bh)) {
|
| 249 | BUFFER_TRACE(bh, "needs writeout, adding to array");
|
| 250 | wbuf[bufs++] = bh;
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| 251 | __journal_file_buffer(jh, commit_transaction,
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| 252 | BJ_Locked);
|
| 253 | jbd_unlock_bh_state(bh);
|
| 254 | if (bufs == journal->j_wbufsize) {
|
| 255 | spin_unlock(&journal->j_list_lock);
|
| 256 | trace_jbd_do_submit_data(journal,
|
| 257 | commit_transaction);
|
| 258 | journal_do_submit_data(wbuf, bufs, write_op);
|
| 259 | bufs = 0;
|
| 260 | goto write_out_data;
|
| 261 | }
|
| 262 | } else if (!locked && buffer_locked(bh)) {
|
| 263 | __journal_file_buffer(jh, commit_transaction,
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| 264 | BJ_Locked);
|
| 265 | jbd_unlock_bh_state(bh);
|
| 266 | put_bh(bh);
|
| 267 | } else {
|
| 268 | BUFFER_TRACE(bh, "writeout complete: unfile");
|
| 269 | if (unlikely(!buffer_uptodate(bh)))
|
| 270 | err = -EIO;
|
| 271 | __journal_unfile_buffer(jh);
|
| 272 | jbd_unlock_bh_state(bh);
|
| 273 | if (locked)
|
| 274 | unlock_buffer(bh);
|
| 275 | release_data_buffer(bh);
|
| 276 | }
|
| 277 |
|
| 278 | if (need_resched() || spin_needbreak(&journal->j_list_lock)) {
|
| 279 | spin_unlock(&journal->j_list_lock);
|
| 280 | goto write_out_data;
|
| 281 | }
|
| 282 | }
|
| 283 | spin_unlock(&journal->j_list_lock);
|
| 284 | trace_jbd_do_submit_data(journal, commit_transaction);
|
| 285 | journal_do_submit_data(wbuf, bufs, write_op);
|
| 286 |
|
| 287 | return err;
|
| 288 | }
|
| 289 |
|
| 290 | |
| 291 | * journal_commit_transaction
|
| 292 | *
|
| 293 | * The primary function for committing a transaction to the log. This
|
| 294 | * function is called by the journal thread to begin a complete commit.
|
| 295 |
|
| 296 | void journal_commit_transaction(journal_t *journal)
|
| 297 | {
|
| 298 | transaction_t *commit_transaction;
|
| 299 | struct journal_head *jh, *new_jh, *descriptor;
|
| 300 | struct buffer_head **wbuf = journal->j_wbuf;
|
| 301 | int bufs;
|
| 302 | int flags;
|
| 303 | int err;
|
| 304 | unsigned int blocknr;
|
| 305 | ktime_t start_time;
|
| 306 | u64 commit_time;
|
| 307 | char *tagp = NULL;
|
| 308 | journal_header_t *header;
|
| 309 | journal_block_tag_t *tag = NULL;
|
| 310 | int space_left = 0;
|
| 311 | int first_tag = 0;
|
| 312 | int tag_flag;
|
| 313 | int i;
|
| 314 | struct blk_plug plug;
|
| 315 | int write_op = WRITE;
|
| 316 |
|
| 317 | |
| 318 | * First job: lock down the current transaction and wait for
|
| 319 | * all outstanding updates to complete.
|
| 320 |
|
| 321 |
|
| 322 |
|
| 323 | if (journal->j_flags & JFS_FLUSHED) {
|
| 324 | jbd_debug(3, "super block updated\n");
|
| 325 | mutex_lock(&journal->j_checkpoint_mutex);
|
| 326 | |
| 327 | * We hold j_checkpoint_mutex so tail cannot change under us.
|
| 328 | * We don't need any special data guarantees for writing sb
|
| 329 | * since journal is empty and it is ok for write to be
|
| 330 | * flushed only with transaction commit.
|
| 331 |
|
| 332 | journal_update_sb_log_tail(journal, journal->j_tail_sequence,
|
| 333 | journal->j_tail, WRITE_SYNC);
|
| 334 | mutex_unlock(&journal->j_checkpoint_mutex);
|
| 335 | } else {
|
| 336 | jbd_debug(3, "superblock not updated\n");
|
| 337 | }
|
| 338 |
|
| 339 | J_ASSERT(journal->j_running_transaction != NULL);
|
| 340 | J_ASSERT(journal->j_committing_transaction == NULL);
|
| 341 |
|
| 342 | commit_transaction = journal->j_running_transaction;
|
| 343 |
|
| 344 | trace_jbd_start_commit(journal, commit_transaction);
|
| 345 | jbd_debug(1, "JBD: starting commit of transaction %d\n",
|
| 346 | commit_transaction->t_tid);
|
| 347 |
|
| 348 | spin_lock(&journal->j_state_lock);
|
| 349 | J_ASSERT(commit_transaction->t_state == T_RUNNING);
|
| 350 | commit_transaction->t_state = T_LOCKED;
|
| 351 |
|
| 352 | trace_jbd_commit_locking(journal, commit_transaction);
|
| 353 | spin_lock(&commit_transaction->t_handle_lock);
|
| 354 | while (commit_transaction->t_updates) {
|
| 355 | DEFINE_WAIT(wait);
|
| 356 |
|
| 357 | prepare_to_wait(&journal->j_wait_updates, &wait,
|
| 358 | TASK_UNINTERRUPTIBLE);
|
| 359 | if (commit_transaction->t_updates) {
|
| 360 | spin_unlock(&commit_transaction->t_handle_lock);
|
| 361 | spin_unlock(&journal->j_state_lock);
|
| 362 | schedule();
|
| 363 | spin_lock(&journal->j_state_lock);
|
| 364 | spin_lock(&commit_transaction->t_handle_lock);
|
| 365 | }
|
| 366 | finish_wait(&journal->j_wait_updates, &wait);
|
| 367 | }
|
| 368 | spin_unlock(&commit_transaction->t_handle_lock);
|
| 369 |
|
| 370 | J_ASSERT (commit_transaction->t_outstanding_credits <=
|
| 371 | journal->j_max_transaction_buffers);
|
| 372 |
|
| 373 | |
| 374 | * First thing we are allowed to do is to discard any remaining
|
| 375 | * BJ_Reserved buffers. Note, it is _not_ permissible to assume
|
| 376 | * that there are no such buffers: if a large filesystem
|
| 377 | * operation like a truncate needs to split itself over multiple
|
| 378 | * transactions, then it may try to do a journal_restart() while
|
| 379 | * there are still BJ_Reserved buffers outstanding. These must
|
| 380 | * be released cleanly from the current transaction.
|
| 381 | *
|
| 382 | * In this case, the filesystem must still reserve write access
|
| 383 | * again before modifying the buffer in the new transaction, but
|
| 384 | * we do not require it to remember exactly which old buffers it
|
| 385 | * has reserved. This is consistent with the existing behaviour
|
| 386 | * that multiple journal_get_write_access() calls to the same
|
| 387 | * buffer are perfectly permissible.
|
| 388 |
|
| 389 | while (commit_transaction->t_reserved_list) {
|
| 390 | jh = commit_transaction->t_reserved_list;
|
| 391 | JBUFFER_TRACE(jh, "reserved, unused: refile");
|
| 392 | |
| 393 | * A journal_get_undo_access()+journal_release_buffer() may
|
| 394 | * leave undo-committed data.
|
| 395 |
|
| 396 | if (jh->b_committed_data) {
|
| 397 | struct buffer_head *bh = jh2bh(jh);
|
| 398 |
|
| 399 | jbd_lock_bh_state(bh);
|
| 400 | jbd_free(jh->b_committed_data, bh->b_size);
|
| 401 | jh->b_committed_data = NULL;
|
| 402 | jbd_unlock_bh_state(bh);
|
| 403 | }
|
| 404 | journal_refile_buffer(journal, jh);
|
| 405 | }
|
| 406 |
|
| 407 | |
| 408 | * Now try to drop any written-back buffers from the journal's
|
| 409 | * checkpoint lists. We do this *before* commit because it potentially
|
| 410 | * frees some memory
|
| 411 |
|
| 412 | spin_lock(&journal->j_list_lock);
|
| 413 | __journal_clean_checkpoint_list(journal);
|
| 414 | spin_unlock(&journal->j_list_lock);
|
| 415 |
|
| 416 | jbd_debug (3, "JBD: commit phase 1\n");
|
| 417 |
|
| 418 | |
| 419 | * Clear revoked flag to reflect there is no revoked buffers
|
| 420 | * in the next transaction which is going to be started.
|
| 421 |
|
| 422 | journal_clear_buffer_revoked_flags(journal);
|
| 423 |
|
| 424 | |
| 425 | * Switch to a new revoke table.
|
| 426 |
|
| 427 | journal_switch_revoke_table(journal);
|
| 428 |
|
| 429 | trace_jbd_commit_flushing(journal, commit_transaction);
|
| 430 | commit_transaction->t_state = T_FLUSH;
|
| 431 | journal->j_committing_transaction = commit_transaction;
|
| 432 | journal->j_running_transaction = NULL;
|
| 433 | start_time = ktime_get();
|
| 434 | commit_transaction->t_log_start = journal->j_head;
|
| 435 | wake_up(&journal->j_wait_transaction_locked);
|
| 436 | spin_unlock(&journal->j_state_lock);
|
| 437 |
|
| 438 | jbd_debug (3, "JBD: commit phase 2\n");
|
| 439 |
|
| 440 | if (tid_geq(journal->j_commit_waited, commit_transaction->t_tid))
|
| 441 | write_op = WRITE_SYNC;
|
| 442 |
|
| 443 | |
| 444 | * Now start flushing things to disk, in the order they appear
|
| 445 | * on the transaction lists. Data blocks go first.
|
| 446 |
|
| 447 | blk_start_plug(&plug);
|
| 448 | err = journal_submit_data_buffers(journal, commit_transaction,
|
| 449 | write_op);
|
| 450 | blk_finish_plug(&plug);
|
| 451 |
|
| 452 | |
| 453 | * Wait for all previously submitted IO to complete.
|
| 454 |
|
| 455 | spin_lock(&journal->j_list_lock);
|
| 456 | while (commit_transaction->t_locked_list) {
|
| 457 | struct buffer_head *bh;
|
| 458 |
|
| 459 | jh = commit_transaction->t_locked_list->b_tprev;
|
| 460 | bh = jh2bh(jh);
|
| 461 | get_bh(bh);
|
| 462 | if (buffer_locked(bh)) {
|
| 463 | spin_unlock(&journal->j_list_lock);
|
| 464 | wait_on_buffer(bh);
|
| 465 | spin_lock(&journal->j_list_lock);
|
| 466 | }
|
| 467 | if (unlikely(!buffer_uptodate(bh))) {
|
| 468 | if (!trylock_page(bh->b_page)) {
|
| 469 | spin_unlock(&journal->j_list_lock);
|
| 470 | lock_page(bh->b_page);
|
| 471 | spin_lock(&journal->j_list_lock);
|
| 472 | }
|
| 473 | if (bh->b_page->mapping)
|
| 474 | set_bit(AS_EIO, &bh->b_page->mapping->flags);
|
| 475 |
|
| 476 | unlock_page(bh->b_page);
|
| 477 | SetPageError(bh->b_page);
|
| 478 | err = -EIO;
|
| 479 | }
|
| 480 | if (!inverted_lock(journal, bh)) {
|
| 481 | put_bh(bh);
|
| 482 | spin_lock(&journal->j_list_lock);
|
| 483 | continue;
|
| 484 | }
|
| 485 | if (buffer_jbd(bh) && bh2jh(bh) == jh &&
|
| 486 | jh->b_transaction == commit_transaction &&
|
| 487 | jh->b_jlist == BJ_Locked)
|
| 488 | __journal_unfile_buffer(jh);
|
| 489 | jbd_unlock_bh_state(bh);
|
| 490 | release_data_buffer(bh);
|
| 491 | cond_resched_lock(&journal->j_list_lock);
|
| 492 | }
|
| 493 | spin_unlock(&journal->j_list_lock);
|
| 494 |
|
| 495 | if (err) {
|
| 496 | char b[BDEVNAME_SIZE];
|
| 497 |
|
| 498 | printk(KERN_WARNING
|
| 499 | "JBD: Detected IO errors while flushing file data "
|
| 500 | "on %s\n", bdevname(journal->j_fs_dev, b));
|
| 501 | if (journal->j_flags & JFS_ABORT_ON_SYNCDATA_ERR)
|
| 502 | journal_abort(journal, err);
|
| 503 | err = 0;
|
| 504 | }
|
| 505 |
|
| 506 | blk_start_plug(&plug);
|
| 507 |
|
| 508 | journal_write_revoke_records(journal, commit_transaction, write_op);
|
| 509 |
|
| 510 | |
| 511 | * If we found any dirty or locked buffers, then we should have
|
| 512 | * looped back up to the write_out_data label. If there weren't
|
| 513 | * any then journal_clean_data_list should have wiped the list
|
| 514 | * clean by now, so check that it is in fact empty.
|
| 515 |
|
| 516 | J_ASSERT (commit_transaction->t_sync_datalist == NULL);
|
| 517 |
|
| 518 | jbd_debug (3, "JBD: commit phase 3\n");
|
| 519 |
|
| 520 | |
| 521 | * Way to go: we have now written out all of the data for a
|
| 522 | * transaction! Now comes the tricky part: we need to write out
|
| 523 | * metadata. Loop over the transaction's entire buffer list:
|
| 524 |
|
| 525 | spin_lock(&journal->j_state_lock);
|
| 526 | commit_transaction->t_state = T_COMMIT;
|
| 527 | spin_unlock(&journal->j_state_lock);
|
| 528 |
|
| 529 | trace_jbd_commit_logging(journal, commit_transaction);
|
| 530 | J_ASSERT(commit_transaction->t_nr_buffers <=
|
| 531 | commit_transaction->t_outstanding_credits);
|
| 532 |
|
| 533 | descriptor = NULL;
|
| 534 | bufs = 0;
|
| 535 | while (commit_transaction->t_buffers) {
|
| 536 |
|
| 537 |
|
| 538 |
|
| 539 | jh = commit_transaction->t_buffers;
|
| 540 |
|
| 541 | |
| 542 | release it.
|
| 543 |
|
| 544 | if (is_journal_aborted(journal)) {
|
| 545 | clear_buffer_jbddirty(jh2bh(jh));
|
| 546 | JBUFFER_TRACE(jh, "journal is aborting: refile");
|
| 547 | journal_refile_buffer(journal, jh);
|
| 548 | |
| 549 | * any descriptor buffers which may have been
|
| 550 | * already allocated, even if we are now
|
| 551 | * aborting.
|
| 552 | if (!commit_transaction->t_buffers)
|
| 553 | goto start_journal_io;
|
| 554 | continue;
|
| 555 | }
|
| 556 |
|
| 557 | |
| 558 | record the metadata buffer.
|
| 559 |
|
| 560 | if (!descriptor) {
|
| 561 | struct buffer_head *bh;
|
| 562 |
|
| 563 | J_ASSERT (bufs == 0);
|
| 564 |
|
| 565 | jbd_debug(4, "JBD: get descriptor\n");
|
| 566 |
|
| 567 | descriptor = journal_get_descriptor_buffer(journal);
|
| 568 | if (!descriptor) {
|
| 569 | journal_abort(journal, -EIO);
|
| 570 | continue;
|
| 571 | }
|
| 572 |
|
| 573 | bh = jh2bh(descriptor);
|
| 574 | jbd_debug(4, "JBD: got buffer %llu (%p)\n",
|
| 575 | (unsigned long long)bh->b_blocknr, bh->b_data);
|
| 576 | header = (journal_header_t *)&bh->b_data[0];
|
| 577 | header->h_magic = cpu_to_be32(JFS_MAGIC_NUMBER);
|
| 578 | header->h_blocktype = cpu_to_be32(JFS_DESCRIPTOR_BLOCK);
|
| 579 | header->h_sequence = cpu_to_be32(commit_transaction->t_tid);
|
| 580 |
|
| 581 | tagp = &bh->b_data[sizeof(journal_header_t)];
|
| 582 | space_left = bh->b_size - sizeof(journal_header_t);
|
| 583 | first_tag = 1;
|
| 584 | set_buffer_jwrite(bh);
|
| 585 | set_buffer_dirty(bh);
|
| 586 | wbuf[bufs++] = bh;
|
| 587 |
|
| 588 | |
| 589 | completion later
|
| 590 | BUFFER_TRACE(bh, "ph3: file as descriptor");
|
| 591 | journal_file_buffer(descriptor, commit_transaction,
|
| 592 | BJ_LogCtl);
|
| 593 | }
|
| 594 |
|
| 595 |
|
| 596 |
|
| 597 | err = journal_next_log_block(journal, &blocknr);
|
| 598 | |
| 599 | and repeat this loop: we'll fall into the
|
| 600 | refile-on-abort condition above.
|
| 601 | if (err) {
|
| 602 | journal_abort(journal, err);
|
| 603 | continue;
|
| 604 | }
|
| 605 |
|
| 606 | |
| 607 | * start_this_handle() uses t_outstanding_credits to determine
|
| 608 | * the free space in the log, but this counter is changed
|
| 609 | * by journal_next_log_block() also.
|
| 610 |
|
| 611 | commit_transaction->t_outstanding_credits--;
|
| 612 |
|
| 613 | |
| 614 | the shadowed buffer! @@@ This can go if we ever get
|
| 615 | rid of the BJ_IO/BJ_Shadow pairing of buffers.
|
| 616 | get_bh(jh2bh(jh));
|
| 617 |
|
| 618 | |
| 619 | (this will requeue both the metadata buffer and the
|
| 620 | temporary IO buffer). new_bh goes on BJ_IO
|
| 621 |
|
| 622 | set_buffer_jwrite(jh2bh(jh));
|
| 623 | |
| 624 | * akpm: journal_write_metadata_buffer() sets
|
| 625 | * new_bh->b_transaction to commit_transaction.
|
| 626 | * We need to clean this up before we release new_bh
|
| 627 | * (which is of type BJ_IO)
|
| 628 |
|
| 629 | JBUFFER_TRACE(jh, "ph3: write metadata");
|
| 630 | flags = journal_write_metadata_buffer(commit_transaction,
|
| 631 | jh, &new_jh, blocknr);
|
| 632 | set_buffer_jwrite(jh2bh(new_jh));
|
| 633 | wbuf[bufs++] = jh2bh(new_jh);
|
| 634 |
|
| 635 | |
| 636 | buffer
|
| 637 |
|
| 638 | tag_flag = 0;
|
| 639 | if (flags & 1)
|
| 640 | tag_flag |= JFS_FLAG_ESCAPE;
|
| 641 | if (!first_tag)
|
| 642 | tag_flag |= JFS_FLAG_SAME_UUID;
|
| 643 |
|
| 644 | tag = (journal_block_tag_t *) tagp;
|
| 645 | tag->t_blocknr = cpu_to_be32(jh2bh(jh)->b_blocknr);
|
| 646 | tag->t_flags = cpu_to_be32(tag_flag);
|
| 647 | tagp += sizeof(journal_block_tag_t);
|
| 648 | space_left -= sizeof(journal_block_tag_t);
|
| 649 |
|
| 650 | if (first_tag) {
|
| 651 | memcpy (tagp, journal->j_uuid, 16);
|
| 652 | tagp += 16;
|
| 653 | space_left -= 16;
|
| 654 | first_tag = 0;
|
| 655 | }
|
| 656 |
|
| 657 | |
| 658 | let the IO rip!
|
| 659 |
|
| 660 | if (bufs == journal->j_wbufsize ||
|
| 661 | commit_transaction->t_buffers == NULL ||
|
| 662 | space_left < sizeof(journal_block_tag_t) + 16) {
|
| 663 |
|
| 664 | jbd_debug(4, "JBD: Submit %d IOs\n", bufs);
|
| 665 |
|
| 666 | |
| 667 | submitting the IOs. "tag" still points to
|
| 668 | the last tag we set up.
|
| 669 |
|
| 670 | tag->t_flags |= cpu_to_be32(JFS_FLAG_LAST_TAG);
|
| 671 |
|
| 672 | start_journal_io:
|
| 673 | for (i = 0; i < bufs; i++) {
|
| 674 | struct buffer_head *bh = wbuf[i];
|
| 675 | lock_buffer(bh);
|
| 676 | clear_buffer_dirty(bh);
|
| 677 | set_buffer_uptodate(bh);
|
| 678 | bh->b_end_io = journal_end_buffer_io_sync;
|
| 679 | |
| 680 | * In data=journal mode, here we can end up
|
| 681 | * writing pagecache data that might be
|
| 682 | * mmapped. Since we can't afford to clean the
|
| 683 | * page and set PageWriteback (see the comment
|
| 684 | * near the other use of _submit_bh()), the
|
| 685 | * data can change while the write is in
|
| 686 | * flight. Tell the block layer to bounce the
|
| 687 | * bio pages if stable pages are required.
|
| 688 |
|
| 689 | _submit_bh(write_op, bh, 1 << BIO_SNAP_STABLE);
|
| 690 | }
|
| 691 | cond_resched();
|
| 692 |
|
| 693 | |
| 694 | time round the loop.
|
| 695 | descriptor = NULL;
|
| 696 | bufs = 0;
|
| 697 | }
|
| 698 | }
|
| 699 |
|
| 700 | blk_finish_plug(&plug);
|
| 701 |
|
| 702 | |
| 703 | the log. Before we can commit it, wait for the IO so far to
|
| 704 | complete. Control buffers being written are on the
|
| 705 | transaction's t_log_list queue, and metadata buffers are on
|
| 706 | the t_iobuf_list queue.
|
| 707 |
|
| 708 | Wait for the buffers in reverse order. That way we are
|
| 709 | less likely to be woken up until all IOs have completed, and
|
| 710 | so we incur less scheduling load.
|
| 711 |
|
| 712 |
|
| 713 | jbd_debug(3, "JBD: commit phase 4\n");
|
| 714 |
|
| 715 | |
| 716 | * akpm: these are BJ_IO, and j_list_lock is not needed.
|
| 717 | * See __journal_try_to_free_buffer.
|
| 718 |
|
| 719 | wait_for_iobuf:
|
| 720 | while (commit_transaction->t_iobuf_list != NULL) {
|
| 721 | struct buffer_head *bh;
|
| 722 |
|
| 723 | jh = commit_transaction->t_iobuf_list->b_tprev;
|
| 724 | bh = jh2bh(jh);
|
| 725 | if (buffer_locked(bh)) {
|
| 726 | wait_on_buffer(bh);
|
| 727 | goto wait_for_iobuf;
|
| 728 | }
|
| 729 | if (cond_resched())
|
| 730 | goto wait_for_iobuf;
|
| 731 |
|
| 732 | if (unlikely(!buffer_uptodate(bh)))
|
| 733 | err = -EIO;
|
| 734 |
|
| 735 | clear_buffer_jwrite(bh);
|
| 736 |
|
| 737 | JBUFFER_TRACE(jh, "ph4: unfile after journal write");
|
| 738 | journal_unfile_buffer(journal, jh);
|
| 739 |
|
| 740 | |
| 741 | * ->t_iobuf_list should contain only dummy buffer_heads
|
| 742 | * which were created by journal_write_metadata_buffer().
|
| 743 |
|
| 744 | BUFFER_TRACE(bh, "dumping temporary bh");
|
| 745 | journal_put_journal_head(jh);
|
| 746 | __brelse(bh);
|
| 747 | J_ASSERT_BH(bh, atomic_read(&bh->b_count) == 0);
|
| 748 | free_buffer_head(bh);
|
| 749 |
|
| 750 | |
| 751 | shadowed buffer
|
| 752 | jh = commit_transaction->t_shadow_list->b_tprev;
|
| 753 | bh = jh2bh(jh);
|
| 754 | clear_buffer_jwrite(bh);
|
| 755 | J_ASSERT_BH(bh, buffer_jbddirty(bh));
|
| 756 |
|
| 757 | |
| 758 | to remember it against this transaction so that when
|
| 759 | we finally commit, we can do any checkpointing
|
| 760 | required.
|
| 761 | JBUFFER_TRACE(jh, "file as BJ_Forget");
|
| 762 | journal_file_buffer(jh, commit_transaction, BJ_Forget);
|
| 763 | |
| 764 | * Wake up any transactions which were waiting for this
|
| 765 | * IO to complete. The barrier must be here so that changes
|
| 766 | * by journal_file_buffer() take effect before wake_up_bit()
|
| 767 | * does the waitqueue check.
|
| 768 |
|
| 769 | smp_mb();
|
| 770 | wake_up_bit(&bh->b_state, BH_Unshadow);
|
| 771 | JBUFFER_TRACE(jh, "brelse shadowed buffer");
|
| 772 | __brelse(bh);
|
| 773 | }
|
| 774 |
|
| 775 | J_ASSERT (commit_transaction->t_shadow_list == NULL);
|
| 776 |
|
| 777 | jbd_debug(3, "JBD: commit phase 5\n");
|
| 778 |
|
| 779 |
|
| 780 | wait_for_ctlbuf:
|
| 781 | while (commit_transaction->t_log_list != NULL) {
|
| 782 | struct buffer_head *bh;
|
| 783 |
|
| 784 | jh = commit_transaction->t_log_list->b_tprev;
|
| 785 | bh = jh2bh(jh);
|
| 786 | if (buffer_locked(bh)) {
|
| 787 | wait_on_buffer(bh);
|
| 788 | goto wait_for_ctlbuf;
|
| 789 | }
|
| 790 | if (cond_resched())
|
| 791 | goto wait_for_ctlbuf;
|
| 792 |
|
| 793 | if (unlikely(!buffer_uptodate(bh)))
|
| 794 | err = -EIO;
|
| 795 |
|
| 796 | BUFFER_TRACE(bh, "ph5: control buffer writeout done: unfile");
|
| 797 | clear_buffer_jwrite(bh);
|
| 798 | journal_unfile_buffer(journal, jh);
|
| 799 | journal_put_journal_head(jh);
|
| 800 | __brelse(bh);
|
| 801 |
|
| 802 | }
|
| 803 |
|
| 804 | if (err)
|
| 805 | journal_abort(journal, err);
|
| 806 |
|
| 807 | jbd_debug(3, "JBD: commit phase 6\n");
|
| 808 |
|
| 809 |
|
| 810 | spin_lock(&journal->j_state_lock);
|
| 811 | J_ASSERT(commit_transaction->t_state == T_COMMIT);
|
| 812 | commit_transaction->t_state = T_COMMIT_RECORD;
|
| 813 | spin_unlock(&journal->j_state_lock);
|
| 814 |
|
| 815 | if (journal_write_commit_record(journal, commit_transaction))
|
| 816 | err = -EIO;
|
| 817 |
|
| 818 | if (err)
|
| 819 | journal_abort(journal, err);
|
| 820 |
|
| 821 | |
| 822 | processing: any buffers committed as a result of this
|
| 823 | transaction can be removed from any checkpoint list it was on
|
| 824 | before.
|
| 825 |
|
| 826 | jbd_debug(3, "JBD: commit phase 7\n");
|
| 827 |
|
| 828 | J_ASSERT(commit_transaction->t_sync_datalist == NULL);
|
| 829 | J_ASSERT(commit_transaction->t_buffers == NULL);
|
| 830 | J_ASSERT(commit_transaction->t_checkpoint_list == NULL);
|
| 831 | J_ASSERT(commit_transaction->t_iobuf_list == NULL);
|
| 832 | J_ASSERT(commit_transaction->t_shadow_list == NULL);
|
| 833 | J_ASSERT(commit_transaction->t_log_list == NULL);
|
| 834 |
|
| 835 | restart_loop:
|
| 836 | |
| 837 | * As there are other places (journal_unmap_buffer()) adding buffers
|
| 838 | * to this list we have to be careful and hold the j_list_lock.
|
| 839 |
|
| 840 | spin_lock(&journal->j_list_lock);
|
| 841 | while (commit_transaction->t_forget) {
|
| 842 | transaction_t *cp_transaction;
|
| 843 | struct buffer_head *bh;
|
| 844 | int try_to_free = 0;
|
| 845 |
|
| 846 | jh = commit_transaction->t_forget;
|
| 847 | spin_unlock(&journal->j_list_lock);
|
| 848 | bh = jh2bh(jh);
|
| 849 | |
| 850 | * Get a reference so that bh cannot be freed before we are
|
| 851 | * done with it.
|
| 852 |
|
| 853 | get_bh(bh);
|
| 854 | jbd_lock_bh_state(bh);
|
| 855 | J_ASSERT_JH(jh, jh->b_transaction == commit_transaction ||
|
| 856 | jh->b_transaction == journal->j_running_transaction);
|
| 857 |
|
| 858 | |
| 859 | * If there is undo-protected committed data against
|
| 860 | * this buffer, then we can remove it now. If it is a
|
| 861 | * buffer needing such protection, the old frozen_data
|
| 862 | * field now points to a committed version of the
|
| 863 | * buffer, so rotate that field to the new committed
|
| 864 | * data.
|
| 865 | *
|
| 866 | * Otherwise, we can just throw away the frozen data now.
|
| 867 |
|
| 868 | if (jh->b_committed_data) {
|
| 869 | jbd_free(jh->b_committed_data, bh->b_size);
|
| 870 | jh->b_committed_data = NULL;
|
| 871 | if (jh->b_frozen_data) {
|
| 872 | jh->b_committed_data = jh->b_frozen_data;
|
| 873 | jh->b_frozen_data = NULL;
|
| 874 | }
|
| 875 | } else if (jh->b_frozen_data) {
|
| 876 | jbd_free(jh->b_frozen_data, bh->b_size);
|
| 877 | jh->b_frozen_data = NULL;
|
| 878 | }
|
| 879 |
|
| 880 | spin_lock(&journal->j_list_lock);
|
| 881 | cp_transaction = jh->b_cp_transaction;
|
| 882 | if (cp_transaction) {
|
| 883 | JBUFFER_TRACE(jh, "remove from old cp transaction");
|
| 884 | __journal_remove_checkpoint(jh);
|
| 885 | }
|
| 886 |
|
| 887 | |
| 888 | * dirty. If the buffer was added to the BJ_Forget list
|
| 889 | * by journal_forget, it may no longer be dirty and
|
| 890 | * there's no point in keeping a checkpoint record for
|
| 891 | * it.
|
| 892 |
|
| 893 | |
| 894 | * A buffer which has been freed while still being journaled by
|
| 895 | * a previous transaction.
|
| 896 |
|
| 897 | if (buffer_freed(bh)) {
|
| 898 | |
| 899 | * If the running transaction is the one containing
|
| 900 | * "add to orphan" operation (b_next_transaction !=
|
| 901 | * NULL), we have to wait for that transaction to
|
| 902 | * commit before we can really get rid of the buffer.
|
| 903 | * So just clear b_modified to not confuse transaction
|
| 904 | * credit accounting and refile the buffer to
|
| 905 | * BJ_Forget of the running transaction. If the just
|
| 906 | * committed transaction contains "add to orphan"
|
| 907 | * operation, we can completely invalidate the buffer
|
| 908 | * now. We are rather throughout in that since the
|
| 909 | * buffer may be still accessible when blocksize <
|
| 910 | * pagesize and it is attached to the last partial
|
| 911 | * page.
|
| 912 |
|
| 913 | jh->b_modified = 0;
|
| 914 | if (!jh->b_next_transaction) {
|
| 915 | clear_buffer_freed(bh);
|
| 916 | clear_buffer_jbddirty(bh);
|
| 917 | clear_buffer_mapped(bh);
|
| 918 | clear_buffer_new(bh);
|
| 919 | clear_buffer_req(bh);
|
| 920 | bh->b_bdev = NULL;
|
| 921 | }
|
| 922 | }
|
| 923 |
|
| 924 | if (buffer_jbddirty(bh)) {
|
| 925 | JBUFFER_TRACE(jh, "add to new checkpointing trans");
|
| 926 | __journal_insert_checkpoint(jh, commit_transaction);
|
| 927 | if (is_journal_aborted(journal))
|
| 928 | clear_buffer_jbddirty(bh);
|
| 929 | } else {
|
| 930 | J_ASSERT_BH(bh, !buffer_dirty(bh));
|
| 931 | |
| 932 | * The buffer on BJ_Forget list and not jbddirty means
|
| 933 | * it has been freed by this transaction and hence it
|
| 934 | * could not have been reallocated until this
|
| 935 | * transaction has committed. *BUT* it could be
|
| 936 | * reallocated once we have written all the data to
|
| 937 | * disk and before we process the buffer on BJ_Forget
|
| 938 | * list.
|
| 939 |
|
| 940 | if (!jh->b_next_transaction)
|
| 941 | try_to_free = 1;
|
| 942 | }
|
| 943 | JBUFFER_TRACE(jh, "refile or unfile freed buffer");
|
| 944 | __journal_refile_buffer(jh);
|
| 945 | jbd_unlock_bh_state(bh);
|
| 946 | if (try_to_free)
|
| 947 | release_buffer_page(bh);
|
| 948 | else
|
| 949 | __brelse(bh);
|
| 950 | cond_resched_lock(&journal->j_list_lock);
|
| 951 | }
|
| 952 | spin_unlock(&journal->j_list_lock);
|
| 953 | |
| 954 | * This is a bit sleazy. We use j_list_lock to protect transition
|
| 955 | * of a transaction into T_FINISHED state and calling
|
| 956 | * __journal_drop_transaction(). Otherwise we could race with
|
| 957 | * other checkpointing code processing the transaction...
|
| 958 |
|
| 959 | spin_lock(&journal->j_state_lock);
|
| 960 | spin_lock(&journal->j_list_lock);
|
| 961 | |
| 962 | * Now recheck if some buffers did not get attached to the transaction
|
| 963 | * while the lock was dropped...
|
| 964 |
|
| 965 | if (commit_transaction->t_forget) {
|
| 966 | spin_unlock(&journal->j_list_lock);
|
| 967 | spin_unlock(&journal->j_state_lock);
|
| 968 | goto restart_loop;
|
| 969 | }
|
| 970 |
|
| 971 |
|
| 972 |
|
| 973 | jbd_debug(3, "JBD: commit phase 8\n");
|
| 974 |
|
| 975 | J_ASSERT(commit_transaction->t_state == T_COMMIT_RECORD);
|
| 976 |
|
| 977 | commit_transaction->t_state = T_FINISHED;
|
| 978 | J_ASSERT(commit_transaction == journal->j_committing_transaction);
|
| 979 | journal->j_commit_sequence = commit_transaction->t_tid;
|
| 980 | journal->j_committing_transaction = NULL;
|
| 981 | commit_time = ktime_to_ns(ktime_sub(ktime_get(), start_time));
|
| 982 |
|
| 983 | |
| 984 | * weight the commit time higher than the average time so we don't
|
| 985 | * react too strongly to vast changes in commit time
|
| 986 |
|
| 987 | if (likely(journal->j_average_commit_time))
|
| 988 | journal->j_average_commit_time = (commit_time*3 +
|
| 989 | journal->j_average_commit_time) / 4;
|
| 990 | else
|
| 991 | journal->j_average_commit_time = commit_time;
|
| 992 |
|
| 993 | spin_unlock(&journal->j_state_lock);
|
| 994 |
|
| 995 | if (commit_transaction->t_checkpoint_list == NULL &&
|
| 996 | commit_transaction->t_checkpoint_io_list == NULL) {
|
| 997 | __journal_drop_transaction(journal, commit_transaction);
|
| 998 | } else {
|
| 999 | if (journal->j_checkpoint_transactions == NULL) {
|
| 1000 | journal->j_checkpoint_transactions = commit_transaction;
|
| 1001 | commit_transaction->t_cpnext = commit_transaction;
|
| 1002 | commit_transaction->t_cpprev = commit_transaction;
|
| 1003 | } else {
|
| 1004 | commit_transaction->t_cpnext =
|
| 1005 | journal->j_checkpoint_transactions;
|
| 1006 | commit_transaction->t_cpprev =
|
| 1007 | commit_transaction->t_cpnext->t_cpprev;
|
| 1008 | commit_transaction->t_cpnext->t_cpprev =
|
| 1009 | commit_transaction;
|
| 1010 | commit_transaction->t_cpprev->t_cpnext =
|
| 1011 | commit_transaction;
|
| 1012 | }
|
| 1013 | }
|
| 1014 | spin_unlock(&journal->j_list_lock);
|
| 1015 |
|
| 1016 | trace_jbd_end_commit(journal, commit_transaction);
|
| 1017 | jbd_debug(1, "JBD: commit %d complete, head %d\n",
|
| 1018 | journal->j_commit_sequence, journal->j_tail_sequence);
|
| 1019 |
|
| 1020 | wake_up(&journal->j_wait_done_commit);
|
| 1021 | }
|