1 /* 2 * linux/include/linux/jbd2.h 3 * 4 * Written by Stephen C. Tweedie <sct@redhat.com> 5 * 6 * Copyright 1998-2000 Red Hat, Inc --- 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 * Definitions for transaction data structures for the buffer cache 13 * filesystem journaling support. 14 */ 15 16 #ifndef _LINUX_JBD2_H 17 #define _LINUX_JBD2_H 18 19 /* Allow this file to be included directly into e2fsprogs */ 20 #ifndef __KERNEL__ 21 #include "jfs_compat.h" 22 #define JBD2_DEBUG 23 #else 24 25 #include <linux/types.h> 26 #include <linux/buffer_head.h> 27 #include <linux/journal-head.h> 28 #include <linux/stddef.h> 29 #include <linux/mutex.h> 30 #include <linux/timer.h> 31 #include <linux/slab.h> 32 #include <crypto/hash.h> 33 #endif 34 35 #define journal_oom_retry 1 36 37 /* 38 * Define JBD2_PARANIOD_IOFAIL to cause a kernel BUG() if ext4 finds 39 * certain classes of error which can occur due to failed IOs. Under 40 * normal use we want ext4 to continue after such errors, because 41 * hardware _can_ fail, but for debugging purposes when running tests on 42 * known-good hardware we may want to trap these errors. 43 */ 44 #undef JBD2_PARANOID_IOFAIL 45 46 /* 47 * The default maximum commit age, in seconds. 48 */ 49 #define JBD2_DEFAULT_MAX_COMMIT_AGE 5 50 51 #ifdef CONFIG_JBD2_DEBUG 52 /* 53 * Define JBD2_EXPENSIVE_CHECKING to enable more expensive internal 54 * consistency checks. By default we don't do this unless 55 * CONFIG_JBD2_DEBUG is on. 56 */ 57 #define JBD2_EXPENSIVE_CHECKING 58 extern ushort jbd2_journal_enable_debug; 59 void __jbd2_debug(int level, const char *file, const char *func, 60 unsigned int line, const char *fmt, ...); 61 62 #define jbd_debug(n, fmt, a...) \ 63 __jbd2_debug((n), __FILE__, __func__, __LINE__, (fmt), ##a) 64 #else 65 #define jbd_debug(n, fmt, a...) /**/ 66 #endif 67 68 extern void *jbd2_alloc(size_t size, gfp_t flags); 69 extern void jbd2_free(void *ptr, size_t size); 70 71 #define JBD2_MIN_JOURNAL_BLOCKS 1024 72 73 #ifdef __KERNEL__ 74 75 /** 76 * typedef handle_t - The handle_t type represents a single atomic update being performed by some process. 77 * 78 * All filesystem modifications made by the process go 79 * through this handle. Recursive operations (such as quota operations) 80 * are gathered into a single update. 81 * 82 * The buffer credits field is used to account for journaled buffers 83 * being modified by the running process. To ensure that there is 84 * enough log space for all outstanding operations, we need to limit the 85 * number of outstanding buffers possible at any time. When the 86 * operation completes, any buffer credits not used are credited back to 87 * the transaction, so that at all times we know how many buffers the 88 * outstanding updates on a transaction might possibly touch. 89 * 90 * This is an opaque datatype. 91 **/ 92 typedef struct jbd2_journal_handle handle_t; /* Atomic operation type */ 93 94 95 /** 96 * typedef journal_t - The journal_t maintains all of the journaling state information for a single filesystem. 97 * 98 * journal_t is linked to from the fs superblock structure. 99 * 100 * We use the journal_t to keep track of all outstanding transaction 101 * activity on the filesystem, and to manage the state of the log 102 * writing process. 103 * 104 * This is an opaque datatype. 105 **/ 106 typedef struct journal_s journal_t; /* Journal control structure */ 107 #endif 108 109 /* 110 * Internal structures used by the logging mechanism: 111 */ 112 113 #define JBD2_MAGIC_NUMBER 0xc03b3998U /* The first 4 bytes of /dev/random! */ 114 115 /* 116 * On-disk structures 117 */ 118 119 /* 120 * Descriptor block types: 121 */ 122 123 #define JBD2_DESCRIPTOR_BLOCK 1 124 #define JBD2_COMMIT_BLOCK 2 125 #define JBD2_SUPERBLOCK_V1 3 126 #define JBD2_SUPERBLOCK_V2 4 127 #define JBD2_REVOKE_BLOCK 5 128 129 /* 130 * Standard header for all descriptor blocks: 131 */ 132 typedef struct journal_header_s 133 { 134 __be32 h_magic; 135 __be32 h_blocktype; 136 __be32 h_sequence; 137 } journal_header_t; 138 139 /* 140 * Checksum types. 141 */ 142 #define JBD2_CRC32_CHKSUM 1 143 #define JBD2_MD5_CHKSUM 2 144 #define JBD2_SHA1_CHKSUM 3 145 #define JBD2_CRC32C_CHKSUM 4 146 147 #define JBD2_CRC32_CHKSUM_SIZE 4 148 149 #define JBD2_CHECKSUM_BYTES (32 / sizeof(u32)) 150 /* 151 * Commit block header for storing transactional checksums: 152 * 153 * NOTE: If FEATURE_COMPAT_CHECKSUM (checksum v1) is set, the h_chksum* 154 * fields are used to store a checksum of the descriptor and data blocks. 155 * 156 * If FEATURE_INCOMPAT_CSUM_V2 (checksum v2) is set, then the h_chksum 157 * field is used to store crc32c(uuid+commit_block). Each journal metadata 158 * block gets its own checksum, and data block checksums are stored in 159 * journal_block_tag (in the descriptor). The other h_chksum* fields are 160 * not used. 161 * 162 * Checksum v1 and v2 are mutually exclusive features. 163 */ 164 struct commit_header { 165 __be32 h_magic; 166 __be32 h_blocktype; 167 __be32 h_sequence; 168 unsigned char h_chksum_type; 169 unsigned char h_chksum_size; 170 unsigned char h_padding[2]; 171 __be32 h_chksum[JBD2_CHECKSUM_BYTES]; 172 __be64 h_commit_sec; 173 __be32 h_commit_nsec; 174 }; 175 176 /* 177 * The block tag: used to describe a single buffer in the journal. 178 * t_blocknr_high is only used if INCOMPAT_64BIT is set, so this 179 * raw struct shouldn't be used for pointer math or sizeof() - use 180 * journal_tag_bytes(journal) instead to compute this. 181 */ 182 typedef struct journal_block_tag_s 183 { 184 __be32 t_blocknr; /* The on-disk block number */ 185 __be16 t_checksum; /* truncated crc32c(uuid+seq+block) */ 186 __be16 t_flags; /* See below */ 187 __be32 t_blocknr_high; /* most-significant high 32bits. */ 188 } journal_block_tag_t; 189 190 #define JBD2_TAG_SIZE32 (offsetof(journal_block_tag_t, t_blocknr_high)) 191 #define JBD2_TAG_SIZE64 (sizeof(journal_block_tag_t)) 192 193 /* Tail of descriptor block, for checksumming */ 194 struct jbd2_journal_block_tail { 195 __be32 t_checksum; /* crc32c(uuid+descr_block) */ 196 }; 197 198 /* 199 * The revoke descriptor: used on disk to describe a series of blocks to 200 * be revoked from the log 201 */ 202 typedef struct jbd2_journal_revoke_header_s 203 { 204 journal_header_t r_header; 205 __be32 r_count; /* Count of bytes used in the block */ 206 } jbd2_journal_revoke_header_t; 207 208 /* Tail of revoke block, for checksumming */ 209 struct jbd2_journal_revoke_tail { 210 __be32 r_checksum; /* crc32c(uuid+revoke_block) */ 211 }; 212 213 /* Definitions for the journal tag flags word: */ 214 #define JBD2_FLAG_ESCAPE 1 /* on-disk block is escaped */ 215 #define JBD2_FLAG_SAME_UUID 2 /* block has same uuid as previous */ 216 #define JBD2_FLAG_DELETED 4 /* block deleted by this transaction */ 217 #define JBD2_FLAG_LAST_TAG 8 /* last tag in this descriptor block */ 218 219 220 /* 221 * The journal superblock. All fields are in big-endian byte order. 222 */ 223 typedef struct journal_superblock_s 224 { 225 /* 0x0000 */ 226 journal_header_t s_header; 227 228 /* 0x000C */ 229 /* Static information describing the journal */ 230 __be32 s_blocksize; /* journal device blocksize */ 231 __be32 s_maxlen; /* total blocks in journal file */ 232 __be32 s_first; /* first block of log information */ 233 234 /* 0x0018 */ 235 /* Dynamic information describing the current state of the log */ 236 __be32 s_sequence; /* first commit ID expected in log */ 237 __be32 s_start; /* blocknr of start of log */ 238 239 /* 0x0020 */ 240 /* Error value, as set by jbd2_journal_abort(). */ 241 __be32 s_errno; 242 243 /* 0x0024 */ 244 /* Remaining fields are only valid in a version-2 superblock */ 245 __be32 s_feature_compat; /* compatible feature set */ 246 __be32 s_feature_incompat; /* incompatible feature set */ 247 __be32 s_feature_ro_compat; /* readonly-compatible feature set */ 248 /* 0x0030 */ 249 __u8 s_uuid[16]; /* 128-bit uuid for journal */ 250 251 /* 0x0040 */ 252 __be32 s_nr_users; /* Nr of filesystems sharing log */ 253 254 __be32 s_dynsuper; /* Blocknr of dynamic superblock copy*/ 255 256 /* 0x0048 */ 257 __be32 s_max_transaction; /* Limit of journal blocks per trans.*/ 258 __be32 s_max_trans_data; /* Limit of data blocks per trans. */ 259 260 /* 0x0050 */ 261 __u8 s_checksum_type; /* checksum type */ 262 __u8 s_padding2[3]; 263 __u32 s_padding[42]; 264 __be32 s_checksum; /* crc32c(superblock) */ 265 266 /* 0x0100 */ 267 __u8 s_users[16*48]; /* ids of all fs'es sharing the log */ 268 /* 0x0400 */ 269 } journal_superblock_t; 270 271 #define JBD2_HAS_COMPAT_FEATURE(j,mask) \ 272 ((j)->j_format_version >= 2 && \ 273 ((j)->j_superblock->s_feature_compat & cpu_to_be32((mask)))) 274 #define JBD2_HAS_RO_COMPAT_FEATURE(j,mask) \ 275 ((j)->j_format_version >= 2 && \ 276 ((j)->j_superblock->s_feature_ro_compat & cpu_to_be32((mask)))) 277 #define JBD2_HAS_INCOMPAT_FEATURE(j,mask) \ 278 ((j)->j_format_version >= 2 && \ 279 ((j)->j_superblock->s_feature_incompat & cpu_to_be32((mask)))) 280 281 #define JBD2_FEATURE_COMPAT_CHECKSUM 0x00000001 282 283 #define JBD2_FEATURE_INCOMPAT_REVOKE 0x00000001 284 #define JBD2_FEATURE_INCOMPAT_64BIT 0x00000002 285 #define JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT 0x00000004 286 #define JBD2_FEATURE_INCOMPAT_CSUM_V2 0x00000008 287 288 /* Features known to this kernel version: */ 289 #define JBD2_KNOWN_COMPAT_FEATURES JBD2_FEATURE_COMPAT_CHECKSUM 290 #define JBD2_KNOWN_ROCOMPAT_FEATURES 0 291 #define JBD2_KNOWN_INCOMPAT_FEATURES (JBD2_FEATURE_INCOMPAT_REVOKE | \ 292 JBD2_FEATURE_INCOMPAT_64BIT | \ 293 JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT | \ 294 JBD2_FEATURE_INCOMPAT_CSUM_V2) 295 296 #ifdef __KERNEL__ 297 298 #include <linux/fs.h> 299 #include <linux/sched.h> 300 301 enum jbd_state_bits { 302 BH_JBD /* Has an attached ext3 journal_head */ 303 = BH_PrivateStart, 304 BH_JWrite, /* Being written to log (@@@ DEBUGGING) */ 305 BH_Freed, /* Has been freed (truncated) */ 306 BH_Revoked, /* Has been revoked from the log */ 307 BH_RevokeValid, /* Revoked flag is valid */ 308 BH_JBDDirty, /* Is dirty but journaled */ 309 BH_State, /* Pins most journal_head state */ 310 BH_JournalHead, /* Pins bh->b_private and jh->b_bh */ 311 BH_Shadow, /* IO on shadow buffer is running */ 312 BH_Verified, /* Metadata block has been verified ok */ 313 BH_JBDPrivateStart, /* First bit available for private use by FS */ 314 }; 315 316 BUFFER_FNS(JBD, jbd) 317 BUFFER_FNS(JWrite, jwrite) 318 BUFFER_FNS(JBDDirty, jbddirty) 319 TAS_BUFFER_FNS(JBDDirty, jbddirty) 320 BUFFER_FNS(Revoked, revoked) 321 TAS_BUFFER_FNS(Revoked, revoked) 322 BUFFER_FNS(RevokeValid, revokevalid) 323 TAS_BUFFER_FNS(RevokeValid, revokevalid) 324 BUFFER_FNS(Freed, freed) 325 BUFFER_FNS(Shadow, shadow) 326 BUFFER_FNS(Verified, verified) 327 328 #include <linux/jbd_common.h> 329 330 #define J_ASSERT(assert) BUG_ON(!(assert)) 331 332 #define J_ASSERT_BH(bh, expr) J_ASSERT(expr) 333 #define J_ASSERT_JH(jh, expr) J_ASSERT(expr) 334 335 #if defined(JBD2_PARANOID_IOFAIL) 336 #define J_EXPECT(expr, why...) J_ASSERT(expr) 337 #define J_EXPECT_BH(bh, expr, why...) J_ASSERT_BH(bh, expr) 338 #define J_EXPECT_JH(jh, expr, why...) J_ASSERT_JH(jh, expr) 339 #else 340 #define __journal_expect(expr, why...) \ 341 ({ \ 342 int val = (expr); \ 343 if (!val) { \ 344 printk(KERN_ERR \ 345 "JBD2 unexpected failure: %s: %s;\n", \ 346 __func__, #expr); \ 347 printk(KERN_ERR why "\n"); \ 348 } \ 349 val; \ 350 }) 351 #define J_EXPECT(expr, why...) __journal_expect(expr, ## why) 352 #define J_EXPECT_BH(bh, expr, why...) __journal_expect(expr, ## why) 353 #define J_EXPECT_JH(jh, expr, why...) __journal_expect(expr, ## why) 354 #endif 355 356 /* Flags in jbd_inode->i_flags */ 357 #define __JI_COMMIT_RUNNING 0 358 /* Commit of the inode data in progress. We use this flag to protect us from 359 * concurrent deletion of inode. We cannot use reference to inode for this 360 * since we cannot afford doing last iput() on behalf of kjournald 361 */ 362 #define JI_COMMIT_RUNNING (1 << __JI_COMMIT_RUNNING) 363 364 /** 365 * struct jbd_inode is the structure linking inodes in ordered mode 366 * present in a transaction so that we can sync them during commit. 367 */ 368 struct jbd2_inode { 369 /* Which transaction does this inode belong to? Either the running 370 * transaction or the committing one. [j_list_lock] */ 371 transaction_t *i_transaction; 372 373 /* Pointer to the running transaction modifying inode's data in case 374 * there is already a committing transaction touching it. [j_list_lock] */ 375 transaction_t *i_next_transaction; 376 377 /* List of inodes in the i_transaction [j_list_lock] */ 378 struct list_head i_list; 379 380 /* VFS inode this inode belongs to [constant during the lifetime 381 * of the structure] */ 382 struct inode *i_vfs_inode; 383 384 /* Flags of inode [j_list_lock] */ 385 unsigned long i_flags; 386 }; 387 388 struct jbd2_revoke_table_s; 389 390 /** 391 * struct handle_s - The handle_s type is the concrete type associated with 392 * handle_t. 393 * @h_transaction: Which compound transaction is this update a part of? 394 * @h_buffer_credits: Number of remaining buffers we are allowed to dirty. 395 * @h_ref: Reference count on this handle 396 * @h_err: Field for caller's use to track errors through large fs operations 397 * @h_sync: flag for sync-on-close 398 * @h_jdata: flag to force data journaling 399 * @h_aborted: flag indicating fatal error on handle 400 **/ 401 402 /* Docbook can't yet cope with the bit fields, but will leave the documentation 403 * in so it can be fixed later. 404 */ 405 406 struct jbd2_journal_handle 407 { 408 union { 409 /* Which compound transaction is this update a part of? */ 410 transaction_t *h_transaction; 411 /* Which journal handle belongs to - used iff h_reserved set */ 412 journal_t *h_journal; 413 }; 414 415 /* Handle reserved for finishing the logical operation */ 416 handle_t *h_rsv_handle; 417 418 /* Number of remaining buffers we are allowed to dirty: */ 419 int h_buffer_credits; 420 421 /* Reference count on this handle */ 422 int h_ref; 423 424 /* Field for caller's use to track errors through large fs */ 425 /* operations */ 426 int h_err; 427 428 /* Flags [no locking] */ 429 unsigned int h_sync: 1; /* sync-on-close */ 430 unsigned int h_jdata: 1; /* force data journaling */ 431 unsigned int h_reserved: 1; /* handle with reserved credits */ 432 unsigned int h_aborted: 1; /* fatal error on handle */ 433 unsigned int h_type: 8; /* for handle statistics */ 434 unsigned int h_line_no: 16; /* for handle statistics */ 435 436 unsigned long h_start_jiffies; 437 unsigned int h_requested_credits; 438 439 #ifdef CONFIG_DEBUG_LOCK_ALLOC 440 struct lockdep_map h_lockdep_map; 441 #endif 442 }; 443 444 445 /* 446 * Some stats for checkpoint phase 447 */ 448 struct transaction_chp_stats_s { 449 unsigned long cs_chp_time; 450 __u32 cs_forced_to_close; 451 __u32 cs_written; 452 __u32 cs_dropped; 453 }; 454 455 /* The transaction_t type is the guts of the journaling mechanism. It 456 * tracks a compound transaction through its various states: 457 * 458 * RUNNING: accepting new updates 459 * LOCKED: Updates still running but we don't accept new ones 460 * RUNDOWN: Updates are tidying up but have finished requesting 461 * new buffers to modify (state not used for now) 462 * FLUSH: All updates complete, but we are still writing to disk 463 * COMMIT: All data on disk, writing commit record 464 * FINISHED: We still have to keep the transaction for checkpointing. 465 * 466 * The transaction keeps track of all of the buffers modified by a 467 * running transaction, and all of the buffers committed but not yet 468 * flushed to home for finished transactions. 469 */ 470 471 /* 472 * Lock ranking: 473 * 474 * j_list_lock 475 * ->jbd_lock_bh_journal_head() (This is "innermost") 476 * 477 * j_state_lock 478 * ->jbd_lock_bh_state() 479 * 480 * jbd_lock_bh_state() 481 * ->j_list_lock 482 * 483 * j_state_lock 484 * ->t_handle_lock 485 * 486 * j_state_lock 487 * ->j_list_lock (journal_unmap_buffer) 488 * 489 */ 490 491 struct transaction_s 492 { 493 /* Pointer to the journal for this transaction. [no locking] */ 494 journal_t *t_journal; 495 496 /* Sequence number for this transaction [no locking] */ 497 tid_t t_tid; 498 499 /* 500 * Transaction's current state 501 * [no locking - only kjournald2 alters this] 502 * [j_list_lock] guards transition of a transaction into T_FINISHED 503 * state and subsequent call of __jbd2_journal_drop_transaction() 504 * FIXME: needs barriers 505 * KLUDGE: [use j_state_lock] 506 */ 507 enum { 508 T_RUNNING, 509 T_LOCKED, 510 T_FLUSH, 511 T_COMMIT, 512 T_COMMIT_DFLUSH, 513 T_COMMIT_JFLUSH, 514 T_COMMIT_CALLBACK, 515 T_FINISHED 516 } t_state; 517 518 /* 519 * Where in the log does this transaction's commit start? [no locking] 520 */ 521 unsigned long t_log_start; 522 523 /* Number of buffers on the t_buffers list [j_list_lock] */ 524 int t_nr_buffers; 525 526 /* 527 * Doubly-linked circular list of all buffers reserved but not yet 528 * modified by this transaction [j_list_lock] 529 */ 530 struct journal_head *t_reserved_list; 531 532 /* 533 * Doubly-linked circular list of all metadata buffers owned by this 534 * transaction [j_list_lock] 535 */ 536 struct journal_head *t_buffers; 537 538 /* 539 * Doubly-linked circular list of all forget buffers (superseded 540 * buffers which we can un-checkpoint once this transaction commits) 541 * [j_list_lock] 542 */ 543 struct journal_head *t_forget; 544 545 /* 546 * Doubly-linked circular list of all buffers still to be flushed before 547 * this transaction can be checkpointed. [j_list_lock] 548 */ 549 struct journal_head *t_checkpoint_list; 550 551 /* 552 * Doubly-linked circular list of all buffers submitted for IO while 553 * checkpointing. [j_list_lock] 554 */ 555 struct journal_head *t_checkpoint_io_list; 556 557 /* 558 * Doubly-linked circular list of metadata buffers being shadowed by log 559 * IO. The IO buffers on the iobuf list and the shadow buffers on this 560 * list match each other one for one at all times. [j_list_lock] 561 */ 562 struct journal_head *t_shadow_list; 563 564 /* 565 * List of inodes whose data we've modified in data=ordered mode. 566 * [j_list_lock] 567 */ 568 struct list_head t_inode_list; 569 570 /* 571 * Protects info related to handles 572 */ 573 spinlock_t t_handle_lock; 574 575 /* 576 * Longest time some handle had to wait for running transaction 577 */ 578 unsigned long t_max_wait; 579 580 /* 581 * When transaction started 582 */ 583 unsigned long t_start; 584 585 /* 586 * When commit was requested 587 */ 588 unsigned long t_requested; 589 590 /* 591 * Checkpointing stats [j_checkpoint_sem] 592 */ 593 struct transaction_chp_stats_s t_chp_stats; 594 595 /* 596 * Number of outstanding updates running on this transaction 597 * [t_handle_lock] 598 */ 599 atomic_t t_updates; 600 601 /* 602 * Number of buffers reserved for use by all handles in this transaction 603 * handle but not yet modified. [t_handle_lock] 604 */ 605 atomic_t t_outstanding_credits; 606 607 /* 608 * Forward and backward links for the circular list of all transactions 609 * awaiting checkpoint. [j_list_lock] 610 */ 611 transaction_t *t_cpnext, *t_cpprev; 612 613 /* 614 * When will the transaction expire (become due for commit), in jiffies? 615 * [no locking] 616 */ 617 unsigned long t_expires; 618 619 /* 620 * When this transaction started, in nanoseconds [no locking] 621 */ 622 ktime_t t_start_time; 623 624 /* 625 * How many handles used this transaction? [t_handle_lock] 626 */ 627 atomic_t t_handle_count; 628 629 /* 630 * This transaction is being forced and some process is 631 * waiting for it to finish. 632 */ 633 unsigned int t_synchronous_commit:1; 634 635 /* Disk flush needs to be sent to fs partition [no locking] */ 636 int t_need_data_flush; 637 638 /* 639 * For use by the filesystem to store fs-specific data 640 * structures associated with the transaction 641 */ 642 struct list_head t_private_list; 643 }; 644 645 struct transaction_run_stats_s { 646 unsigned long rs_wait; 647 unsigned long rs_request_delay; 648 unsigned long rs_running; 649 unsigned long rs_locked; 650 unsigned long rs_flushing; 651 unsigned long rs_logging; 652 653 __u32 rs_handle_count; 654 __u32 rs_blocks; 655 __u32 rs_blocks_logged; 656 }; 657 658 struct transaction_stats_s { 659 unsigned long ts_tid; 660 unsigned long ts_requested; 661 struct transaction_run_stats_s run; 662 }; 663 664 static inline unsigned long 665 jbd2_time_diff(unsigned long start, unsigned long end) 666 { 667 if (end >= start) 668 return end - start; 669 670 return end + (MAX_JIFFY_OFFSET - start); 671 } 672 673 #define JBD2_NR_BATCH 64 674 675 /** 676 * struct journal_s - The journal_s type is the concrete type associated with 677 * journal_t. 678 * @j_flags: General journaling state flags 679 * @j_errno: Is there an outstanding uncleared error on the journal (from a 680 * prior abort)? 681 * @j_sb_buffer: First part of superblock buffer 682 * @j_superblock: Second part of superblock buffer 683 * @j_format_version: Version of the superblock format 684 * @j_state_lock: Protect the various scalars in the journal 685 * @j_barrier_count: Number of processes waiting to create a barrier lock 686 * @j_barrier: The barrier lock itself 687 * @j_running_transaction: The current running transaction.. 688 * @j_committing_transaction: the transaction we are pushing to disk 689 * @j_checkpoint_transactions: a linked circular list of all transactions 690 * waiting for checkpointing 691 * @j_wait_transaction_locked: Wait queue for waiting for a locked transaction 692 * to start committing, or for a barrier lock to be released 693 * @j_wait_done_commit: Wait queue for waiting for commit to complete 694 * @j_wait_commit: Wait queue to trigger commit 695 * @j_wait_updates: Wait queue to wait for updates to complete 696 * @j_wait_reserved: Wait queue to wait for reserved buffer credits to drop 697 * @j_checkpoint_mutex: Mutex for locking against concurrent checkpoints 698 * @j_head: Journal head - identifies the first unused block in the journal 699 * @j_tail: Journal tail - identifies the oldest still-used block in the 700 * journal. 701 * @j_free: Journal free - how many free blocks are there in the journal? 702 * @j_first: The block number of the first usable block 703 * @j_last: The block number one beyond the last usable block 704 * @j_dev: Device where we store the journal 705 * @j_blocksize: blocksize for the location where we store the journal. 706 * @j_blk_offset: starting block offset for into the device where we store the 707 * journal 708 * @j_fs_dev: Device which holds the client fs. For internal journal this will 709 * be equal to j_dev 710 * @j_reserved_credits: Number of buffers reserved from the running transaction 711 * @j_maxlen: Total maximum capacity of the journal region on disk. 712 * @j_list_lock: Protects the buffer lists and internal buffer state. 713 * @j_inode: Optional inode where we store the journal. If present, all journal 714 * block numbers are mapped into this inode via bmap(). 715 * @j_tail_sequence: Sequence number of the oldest transaction in the log 716 * @j_transaction_sequence: Sequence number of the next transaction to grant 717 * @j_commit_sequence: Sequence number of the most recently committed 718 * transaction 719 * @j_commit_request: Sequence number of the most recent transaction wanting 720 * commit 721 * @j_uuid: Uuid of client object. 722 * @j_task: Pointer to the current commit thread for this journal 723 * @j_max_transaction_buffers: Maximum number of metadata buffers to allow in a 724 * single compound commit transaction 725 * @j_commit_interval: What is the maximum transaction lifetime before we begin 726 * a commit? 727 * @j_commit_timer: The timer used to wakeup the commit thread 728 * @j_revoke_lock: Protect the revoke table 729 * @j_revoke: The revoke table - maintains the list of revoked blocks in the 730 * current transaction. 731 * @j_revoke_table: alternate revoke tables for j_revoke 732 * @j_wbuf: array of buffer_heads for jbd2_journal_commit_transaction 733 * @j_wbufsize: maximum number of buffer_heads allowed in j_wbuf, the 734 * number that will fit in j_blocksize 735 * @j_last_sync_writer: most recent pid which did a synchronous write 736 * @j_history: Buffer storing the transactions statistics history 737 * @j_history_max: Maximum number of transactions in the statistics history 738 * @j_history_cur: Current number of transactions in the statistics history 739 * @j_history_lock: Protect the transactions statistics history 740 * @j_proc_entry: procfs entry for the jbd statistics directory 741 * @j_stats: Overall statistics 742 * @j_private: An opaque pointer to fs-private information. 743 */ 744 745 struct journal_s 746 { 747 /* General journaling state flags [j_state_lock] */ 748 unsigned long j_flags; 749 750 /* 751 * Is there an outstanding uncleared error on the journal (from a prior 752 * abort)? [j_state_lock] 753 */ 754 int j_errno; 755 756 /* The superblock buffer */ 757 struct buffer_head *j_sb_buffer; 758 journal_superblock_t *j_superblock; 759 760 /* Version of the superblock format */ 761 int j_format_version; 762 763 /* 764 * Protect the various scalars in the journal 765 */ 766 rwlock_t j_state_lock; 767 768 /* 769 * Number of processes waiting to create a barrier lock [j_state_lock] 770 */ 771 int j_barrier_count; 772 773 /* The barrier lock itself */ 774 struct mutex j_barrier; 775 776 /* 777 * Transactions: The current running transaction... 778 * [j_state_lock] [caller holding open handle] 779 */ 780 transaction_t *j_running_transaction; 781 782 /* 783 * the transaction we are pushing to disk 784 * [j_state_lock] [caller holding open handle] 785 */ 786 transaction_t *j_committing_transaction; 787 788 /* 789 * ... and a linked circular list of all transactions waiting for 790 * checkpointing. [j_list_lock] 791 */ 792 transaction_t *j_checkpoint_transactions; 793 794 /* 795 * Wait queue for waiting for a locked transaction to start committing, 796 * or for a barrier lock to be released 797 */ 798 wait_queue_head_t j_wait_transaction_locked; 799 800 /* Wait queue for waiting for commit to complete */ 801 wait_queue_head_t j_wait_done_commit; 802 803 /* Wait queue to trigger commit */ 804 wait_queue_head_t j_wait_commit; 805 806 /* Wait queue to wait for updates to complete */ 807 wait_queue_head_t j_wait_updates; 808 809 /* Wait queue to wait for reserved buffer credits to drop */ 810 wait_queue_head_t j_wait_reserved; 811 812 /* Semaphore for locking against concurrent checkpoints */ 813 struct mutex j_checkpoint_mutex; 814 815 /* 816 * List of buffer heads used by the checkpoint routine. This 817 * was moved from jbd2_log_do_checkpoint() to reduce stack 818 * usage. Access to this array is controlled by the 819 * j_checkpoint_mutex. [j_checkpoint_mutex] 820 */ 821 struct buffer_head *j_chkpt_bhs[JBD2_NR_BATCH]; 822 823 /* 824 * Journal head: identifies the first unused block in the journal. 825 * [j_state_lock] 826 */ 827 unsigned long j_head; 828 829 /* 830 * Journal tail: identifies the oldest still-used block in the journal. 831 * [j_state_lock] 832 */ 833 unsigned long j_tail; 834 835 /* 836 * Journal free: how many free blocks are there in the journal? 837 * [j_state_lock] 838 */ 839 unsigned long j_free; 840 841 /* 842 * Journal start and end: the block numbers of the first usable block 843 * and one beyond the last usable block in the journal. [j_state_lock] 844 */ 845 unsigned long j_first; 846 unsigned long j_last; 847 848 /* 849 * Device, blocksize and starting block offset for the location where we 850 * store the journal. 851 */ 852 struct block_device *j_dev; 853 int j_blocksize; 854 unsigned long long j_blk_offset; 855 char j_devname[BDEVNAME_SIZE+24]; 856 857 /* 858 * Device which holds the client fs. For internal journal this will be 859 * equal to j_dev. 860 */ 861 struct block_device *j_fs_dev; 862 863 /* Total maximum capacity of the journal region on disk. */ 864 unsigned int j_maxlen; 865 866 /* Number of buffers reserved from the running transaction */ 867 atomic_t j_reserved_credits; 868 869 /* 870 * Protects the buffer lists and internal buffer state. 871 */ 872 spinlock_t j_list_lock; 873 874 /* Optional inode where we store the journal. If present, all */ 875 /* journal block numbers are mapped into this inode via */ 876 /* bmap(). */ 877 struct inode *j_inode; 878 879 /* 880 * Sequence number of the oldest transaction in the log [j_state_lock] 881 */ 882 tid_t j_tail_sequence; 883 884 /* 885 * Sequence number of the next transaction to grant [j_state_lock] 886 */ 887 tid_t j_transaction_sequence; 888 889 /* 890 * Sequence number of the most recently committed transaction 891 * [j_state_lock]. 892 */ 893 tid_t j_commit_sequence; 894 895 /* 896 * Sequence number of the most recent transaction wanting commit 897 * [j_state_lock] 898 */ 899 tid_t j_commit_request; 900 901 /* 902 * Journal uuid: identifies the object (filesystem, LVM volume etc) 903 * backed by this journal. This will eventually be replaced by an array 904 * of uuids, allowing us to index multiple devices within a single 905 * journal and to perform atomic updates across them. 906 */ 907 __u8 j_uuid[16]; 908 909 /* Pointer to the current commit thread for this journal */ 910 struct task_struct *j_task; 911 912 /* 913 * Maximum number of metadata buffers to allow in a single compound 914 * commit transaction 915 */ 916 int j_max_transaction_buffers; 917 918 /* 919 * What is the maximum transaction lifetime before we begin a commit? 920 */ 921 unsigned long j_commit_interval; 922 923 /* The timer used to wakeup the commit thread: */ 924 struct timer_list j_commit_timer; 925 926 /* 927 * The revoke table: maintains the list of revoked blocks in the 928 * current transaction. [j_revoke_lock] 929 */ 930 spinlock_t j_revoke_lock; 931 struct jbd2_revoke_table_s *j_revoke; 932 struct jbd2_revoke_table_s *j_revoke_table[2]; 933 934 /* 935 * array of bhs for jbd2_journal_commit_transaction 936 */ 937 struct buffer_head **j_wbuf; 938 int j_wbufsize; 939 940 /* 941 * this is the pid of hte last person to run a synchronous operation 942 * through the journal 943 */ 944 pid_t j_last_sync_writer; 945 946 /* 947 * the average amount of time in nanoseconds it takes to commit a 948 * transaction to disk. [j_state_lock] 949 */ 950 u64 j_average_commit_time; 951 952 /* 953 * minimum and maximum times that we should wait for 954 * additional filesystem operations to get batched into a 955 * synchronous handle in microseconds 956 */ 957 u32 j_min_batch_time; 958 u32 j_max_batch_time; 959 960 /* This function is called when a transaction is closed */ 961 void (*j_commit_callback)(journal_t *, 962 transaction_t *); 963 964 /* 965 * Journal statistics 966 */ 967 spinlock_t j_history_lock; 968 struct proc_dir_entry *j_proc_entry; 969 struct transaction_stats_s j_stats; 970 971 /* Failed journal commit ID */ 972 unsigned int j_failed_commit; 973 974 /* 975 * An opaque pointer to fs-private information. ext3 puts its 976 * superblock pointer here 977 */ 978 void *j_private; 979 980 /* Reference to checksum algorithm driver via cryptoapi */ 981 struct crypto_shash *j_chksum_driver; 982 983 /* Precomputed journal UUID checksum for seeding other checksums */ 984 __u32 j_csum_seed; 985 }; 986 987 /* 988 * Journal flag definitions 989 */ 990 #define JBD2_UNMOUNT 0x001 /* Journal thread is being destroyed */ 991 #define JBD2_ABORT 0x002 /* Journaling has been aborted for errors. */ 992 #define JBD2_ACK_ERR 0x004 /* The errno in the sb has been acked */ 993 #define JBD2_FLUSHED 0x008 /* The journal superblock has been flushed */ 994 #define JBD2_LOADED 0x010 /* The journal superblock has been loaded */ 995 #define JBD2_BARRIER 0x020 /* Use IDE barriers */ 996 #define JBD2_ABORT_ON_SYNCDATA_ERR 0x040 /* Abort the journal on file 997 * data write error in ordered 998 * mode */ 999 1000 /* 1001 * Function declarations for the journaling transaction and buffer 1002 * management 1003 */ 1004 1005 /* Filing buffers */ 1006 extern void jbd2_journal_unfile_buffer(journal_t *, struct journal_head *); 1007 extern void __jbd2_journal_refile_buffer(struct journal_head *); 1008 extern void jbd2_journal_refile_buffer(journal_t *, struct journal_head *); 1009 extern void __jbd2_journal_file_buffer(struct journal_head *, transaction_t *, int); 1010 extern void __journal_free_buffer(struct journal_head *bh); 1011 extern void jbd2_journal_file_buffer(struct journal_head *, transaction_t *, int); 1012 extern void __journal_clean_data_list(transaction_t *transaction); 1013 static inline void jbd2_file_log_bh(struct list_head *head, struct buffer_head *bh) 1014 { 1015 list_add_tail(&bh->b_assoc_buffers, head); 1016 } 1017 static inline void jbd2_unfile_log_bh(struct buffer_head *bh) 1018 { 1019 list_del_init(&bh->b_assoc_buffers); 1020 } 1021 1022 /* Log buffer allocation */ 1023 struct buffer_head *jbd2_journal_get_descriptor_buffer(journal_t *journal); 1024 int jbd2_journal_next_log_block(journal_t *, unsigned long long *); 1025 int jbd2_journal_get_log_tail(journal_t *journal, tid_t *tid, 1026 unsigned long *block); 1027 void __jbd2_update_log_tail(journal_t *journal, tid_t tid, unsigned long block); 1028 void jbd2_update_log_tail(journal_t *journal, tid_t tid, unsigned long block); 1029 1030 /* Commit management */ 1031 extern void jbd2_journal_commit_transaction(journal_t *); 1032 1033 /* Checkpoint list management */ 1034 int __jbd2_journal_clean_checkpoint_list(journal_t *journal); 1035 int __jbd2_journal_remove_checkpoint(struct journal_head *); 1036 void __jbd2_journal_insert_checkpoint(struct journal_head *, transaction_t *); 1037 1038 1039 /* 1040 * Triggers 1041 */ 1042 1043 struct jbd2_buffer_trigger_type { 1044 /* 1045 * Fired a the moment data to write to the journal are known to be 1046 * stable - so either at the moment b_frozen_data is created or just 1047 * before a buffer is written to the journal. mapped_data is a mapped 1048 * buffer that is the frozen data for commit. 1049 */ 1050 void (*t_frozen)(struct jbd2_buffer_trigger_type *type, 1051 struct buffer_head *bh, void *mapped_data, 1052 size_t size); 1053 1054 /* 1055 * Fired during journal abort for dirty buffers that will not be 1056 * committed. 1057 */ 1058 void (*t_abort)(struct jbd2_buffer_trigger_type *type, 1059 struct buffer_head *bh); 1060 }; 1061 1062 extern void jbd2_buffer_frozen_trigger(struct journal_head *jh, 1063 void *mapped_data, 1064 struct jbd2_buffer_trigger_type *triggers); 1065 extern void jbd2_buffer_abort_trigger(struct journal_head *jh, 1066 struct jbd2_buffer_trigger_type *triggers); 1067 1068 /* Buffer IO */ 1069 extern int jbd2_journal_write_metadata_buffer(transaction_t *transaction, 1070 struct journal_head *jh_in, 1071 struct buffer_head **bh_out, 1072 sector_t blocknr); 1073 1074 /* Transaction locking */ 1075 extern void __wait_on_journal (journal_t *); 1076 1077 /* Transaction cache support */ 1078 extern void jbd2_journal_destroy_transaction_cache(void); 1079 extern int jbd2_journal_init_transaction_cache(void); 1080 extern void jbd2_journal_free_transaction(transaction_t *); 1081 1082 /* 1083 * Journal locking. 1084 * 1085 * We need to lock the journal during transaction state changes so that nobody 1086 * ever tries to take a handle on the running transaction while we are in the 1087 * middle of moving it to the commit phase. j_state_lock does this. 1088 * 1089 * Note that the locking is completely interrupt unsafe. We never touch 1090 * journal structures from interrupts. 1091 */ 1092 1093 static inline handle_t *journal_current_handle(void) 1094 { 1095 return current->journal_info; 1096 } 1097 1098 /* The journaling code user interface: 1099 * 1100 * Create and destroy handles 1101 * Register buffer modifications against the current transaction. 1102 */ 1103 1104 extern handle_t *jbd2_journal_start(journal_t *, int nblocks); 1105 extern handle_t *jbd2__journal_start(journal_t *, int blocks, int rsv_blocks, 1106 gfp_t gfp_mask, unsigned int type, 1107 unsigned int line_no); 1108 extern int jbd2_journal_restart(handle_t *, int nblocks); 1109 extern int jbd2__journal_restart(handle_t *, int nblocks, gfp_t gfp_mask); 1110 extern int jbd2_journal_start_reserved(handle_t *handle, 1111 unsigned int type, unsigned int line_no); 1112 extern void jbd2_journal_free_reserved(handle_t *handle); 1113 extern int jbd2_journal_extend (handle_t *, int nblocks); 1114 extern int jbd2_journal_get_write_access(handle_t *, struct buffer_head *); 1115 extern int jbd2_journal_get_create_access (handle_t *, struct buffer_head *); 1116 extern int jbd2_journal_get_undo_access(handle_t *, struct buffer_head *); 1117 void jbd2_journal_set_triggers(struct buffer_head *, 1118 struct jbd2_buffer_trigger_type *type); 1119 extern int jbd2_journal_dirty_metadata (handle_t *, struct buffer_head *); 1120 extern int jbd2_journal_forget (handle_t *, struct buffer_head *); 1121 extern void journal_sync_buffer (struct buffer_head *); 1122 extern int jbd2_journal_invalidatepage(journal_t *, 1123 struct page *, unsigned int, unsigned int); 1124 extern int jbd2_journal_try_to_free_buffers(journal_t *, struct page *, gfp_t); 1125 extern int jbd2_journal_stop(handle_t *); 1126 extern int jbd2_journal_flush (journal_t *); 1127 extern void jbd2_journal_lock_updates (journal_t *); 1128 extern void jbd2_journal_unlock_updates (journal_t *); 1129 1130 extern journal_t * jbd2_journal_init_dev(struct block_device *bdev, 1131 struct block_device *fs_dev, 1132 unsigned long long start, int len, int bsize); 1133 extern journal_t * jbd2_journal_init_inode (struct inode *); 1134 extern int jbd2_journal_update_format (journal_t *); 1135 extern int jbd2_journal_check_used_features 1136 (journal_t *, unsigned long, unsigned long, unsigned long); 1137 extern int jbd2_journal_check_available_features 1138 (journal_t *, unsigned long, unsigned long, unsigned long); 1139 extern int jbd2_journal_set_features 1140 (journal_t *, unsigned long, unsigned long, unsigned long); 1141 extern void jbd2_journal_clear_features 1142 (journal_t *, unsigned long, unsigned long, unsigned long); 1143 extern int jbd2_journal_load (journal_t *journal); 1144 extern int jbd2_journal_destroy (journal_t *); 1145 extern int jbd2_journal_recover (journal_t *journal); 1146 extern int jbd2_journal_wipe (journal_t *, int); 1147 extern int jbd2_journal_skip_recovery (journal_t *); 1148 extern void jbd2_journal_update_sb_errno(journal_t *); 1149 extern void jbd2_journal_update_sb_log_tail (journal_t *, tid_t, 1150 unsigned long, int); 1151 extern void __jbd2_journal_abort_hard (journal_t *); 1152 extern void jbd2_journal_abort (journal_t *, int); 1153 extern int jbd2_journal_errno (journal_t *); 1154 extern void jbd2_journal_ack_err (journal_t *); 1155 extern int jbd2_journal_clear_err (journal_t *); 1156 extern int jbd2_journal_bmap(journal_t *, unsigned long, unsigned long long *); 1157 extern int jbd2_journal_force_commit(journal_t *); 1158 extern int jbd2_journal_force_commit_nested(journal_t *); 1159 extern int jbd2_journal_file_inode(handle_t *handle, struct jbd2_inode *inode); 1160 extern int jbd2_journal_begin_ordered_truncate(journal_t *journal, 1161 struct jbd2_inode *inode, loff_t new_size); 1162 extern void jbd2_journal_init_jbd_inode(struct jbd2_inode *jinode, struct inode *inode); 1163 extern void jbd2_journal_release_jbd_inode(journal_t *journal, struct jbd2_inode *jinode); 1164 1165 /* 1166 * journal_head management 1167 */ 1168 struct journal_head *jbd2_journal_add_journal_head(struct buffer_head *bh); 1169 struct journal_head *jbd2_journal_grab_journal_head(struct buffer_head *bh); 1170 void jbd2_journal_put_journal_head(struct journal_head *jh); 1171 1172 /* 1173 * handle management 1174 */ 1175 extern struct kmem_cache *jbd2_handle_cache; 1176 1177 static inline handle_t *jbd2_alloc_handle(gfp_t gfp_flags) 1178 { 1179 return kmem_cache_zalloc(jbd2_handle_cache, gfp_flags); 1180 } 1181 1182 static inline void jbd2_free_handle(handle_t *handle) 1183 { 1184 kmem_cache_free(jbd2_handle_cache, handle); 1185 } 1186 1187 /* 1188 * jbd2_inode management (optional, for those file systems that want to use 1189 * dynamically allocated jbd2_inode structures) 1190 */ 1191 extern struct kmem_cache *jbd2_inode_cache; 1192 1193 static inline struct jbd2_inode *jbd2_alloc_inode(gfp_t gfp_flags) 1194 { 1195 return kmem_cache_alloc(jbd2_inode_cache, gfp_flags); 1196 } 1197 1198 static inline void jbd2_free_inode(struct jbd2_inode *jinode) 1199 { 1200 kmem_cache_free(jbd2_inode_cache, jinode); 1201 } 1202 1203 /* Primary revoke support */ 1204 #define JOURNAL_REVOKE_DEFAULT_HASH 256 1205 extern int jbd2_journal_init_revoke(journal_t *, int); 1206 extern void jbd2_journal_destroy_revoke_caches(void); 1207 extern int jbd2_journal_init_revoke_caches(void); 1208 1209 extern void jbd2_journal_destroy_revoke(journal_t *); 1210 extern int jbd2_journal_revoke (handle_t *, unsigned long long, struct buffer_head *); 1211 extern int jbd2_journal_cancel_revoke(handle_t *, struct journal_head *); 1212 extern void jbd2_journal_write_revoke_records(journal_t *journal, 1213 transaction_t *transaction, 1214 struct list_head *log_bufs, 1215 int write_op); 1216 1217 /* Recovery revoke support */ 1218 extern int jbd2_journal_set_revoke(journal_t *, unsigned long long, tid_t); 1219 extern int jbd2_journal_test_revoke(journal_t *, unsigned long long, tid_t); 1220 extern void jbd2_journal_clear_revoke(journal_t *); 1221 extern void jbd2_journal_switch_revoke_table(journal_t *journal); 1222 extern void jbd2_clear_buffer_revoked_flags(journal_t *journal); 1223 1224 /* 1225 * The log thread user interface: 1226 * 1227 * Request space in the current transaction, and force transaction commit 1228 * transitions on demand. 1229 */ 1230 1231 int jbd2_log_start_commit(journal_t *journal, tid_t tid); 1232 int __jbd2_log_start_commit(journal_t *journal, tid_t tid); 1233 int jbd2_journal_start_commit(journal_t *journal, tid_t *tid); 1234 int jbd2_log_wait_commit(journal_t *journal, tid_t tid); 1235 int jbd2_complete_transaction(journal_t *journal, tid_t tid); 1236 int jbd2_log_do_checkpoint(journal_t *journal); 1237 int jbd2_trans_will_send_data_barrier(journal_t *journal, tid_t tid); 1238 1239 void __jbd2_log_wait_for_space(journal_t *journal); 1240 extern void __jbd2_journal_drop_transaction(journal_t *, transaction_t *); 1241 extern int jbd2_cleanup_journal_tail(journal_t *); 1242 1243 /* Debugging code only: */ 1244 1245 #define jbd_ENOSYS() \ 1246 do { \ 1247 printk (KERN_ERR "JBD unimplemented function %s\n", __func__); \ 1248 current->state = TASK_UNINTERRUPTIBLE; \ 1249 schedule(); \ 1250 } while (1) 1251 1252 /* 1253 * is_journal_abort 1254 * 1255 * Simple test wrapper function to test the JBD2_ABORT state flag. This 1256 * bit, when set, indicates that we have had a fatal error somewhere, 1257 * either inside the journaling layer or indicated to us by the client 1258 * (eg. ext3), and that we and should not commit any further 1259 * transactions. 1260 */ 1261 1262 static inline int is_journal_aborted(journal_t *journal) 1263 { 1264 return journal->j_flags & JBD2_ABORT; 1265 } 1266 1267 static inline int is_handle_aborted(handle_t *handle) 1268 { 1269 if (handle->h_aborted || !handle->h_transaction) 1270 return 1; 1271 return is_journal_aborted(handle->h_transaction->t_journal); 1272 } 1273 1274 static inline void jbd2_journal_abort_handle(handle_t *handle) 1275 { 1276 handle->h_aborted = 1; 1277 } 1278 1279 #endif /* __KERNEL__ */ 1280 1281 /* Comparison functions for transaction IDs: perform comparisons using 1282 * modulo arithmetic so that they work over sequence number wraps. */ 1283 1284 static inline int tid_gt(tid_t x, tid_t y) 1285 { 1286 int difference = (x - y); 1287 return (difference > 0); 1288 } 1289 1290 static inline int tid_geq(tid_t x, tid_t y) 1291 { 1292 int difference = (x - y); 1293 return (difference >= 0); 1294 } 1295 1296 extern int jbd2_journal_blocks_per_page(struct inode *inode); 1297 extern size_t journal_tag_bytes(journal_t *journal); 1298 1299 /* 1300 * We reserve t_outstanding_credits >> JBD2_CONTROL_BLOCKS_SHIFT for 1301 * transaction control blocks. 1302 */ 1303 #define JBD2_CONTROL_BLOCKS_SHIFT 5 1304 1305 /* 1306 * Return the minimum number of blocks which must be free in the journal 1307 * before a new transaction may be started. Must be called under j_state_lock. 1308 */ 1309 static inline int jbd2_space_needed(journal_t *journal) 1310 { 1311 int nblocks = journal->j_max_transaction_buffers; 1312 return nblocks + (nblocks >> JBD2_CONTROL_BLOCKS_SHIFT); 1313 } 1314 1315 /* 1316 * Return number of free blocks in the log. Must be called under j_state_lock. 1317 */ 1318 static inline unsigned long jbd2_log_space_left(journal_t *journal) 1319 { 1320 /* Allow for rounding errors */ 1321 unsigned long free = journal->j_free - 32; 1322 1323 if (journal->j_committing_transaction) { 1324 unsigned long committing = atomic_read(&journal-> 1325 j_committing_transaction->t_outstanding_credits); 1326 1327 /* Transaction + control blocks */ 1328 free -= committing + (committing >> JBD2_CONTROL_BLOCKS_SHIFT); 1329 } 1330 return free; 1331 } 1332 1333 /* 1334 * Definitions which augment the buffer_head layer 1335 */ 1336 1337 /* journaling buffer types */ 1338 #define BJ_None 0 /* Not journaled */ 1339 #define BJ_Metadata 1 /* Normal journaled metadata */ 1340 #define BJ_Forget 2 /* Buffer superseded by this transaction */ 1341 #define BJ_Shadow 3 /* Buffer contents being shadowed to the log */ 1342 #define BJ_Reserved 4 /* Buffer is reserved for access by journal */ 1343 #define BJ_Types 5 1344 1345 extern int jbd_blocks_per_page(struct inode *inode); 1346 1347 /* JBD uses a CRC32 checksum */ 1348 #define JBD_MAX_CHECKSUM_SIZE 4 1349 1350 static inline u32 jbd2_chksum(journal_t *journal, u32 crc, 1351 const void *address, unsigned int length) 1352 { 1353 struct { 1354 struct shash_desc shash; 1355 char ctx[JBD_MAX_CHECKSUM_SIZE]; 1356 } desc; 1357 int err; 1358 1359 BUG_ON(crypto_shash_descsize(journal->j_chksum_driver) > 1360 JBD_MAX_CHECKSUM_SIZE); 1361 1362 desc.shash.tfm = journal->j_chksum_driver; 1363 desc.shash.flags = 0; 1364 *(u32 *)desc.ctx = crc; 1365 1366 err = crypto_shash_update(&desc.shash, address, length); 1367 BUG_ON(err); 1368 1369 return *(u32 *)desc.ctx; 1370 } 1371 1372 /* Return most recent uncommitted transaction */ 1373 static inline tid_t jbd2_get_latest_transaction(journal_t *journal) 1374 { 1375 tid_t tid; 1376 1377 read_lock(&journal->j_state_lock); 1378 tid = journal->j_commit_request; 1379 if (journal->j_running_transaction) 1380 tid = journal->j_running_transaction->t_tid; 1381 read_unlock(&journal->j_state_lock); 1382 return tid; 1383 } 1384 1385 #ifdef __KERNEL__ 1386 1387 #define buffer_trace_init(bh) do {} while (0) 1388 #define print_buffer_fields(bh) do {} while (0) 1389 #define print_buffer_trace(bh) do {} while (0) 1390 #define BUFFER_TRACE(bh, info) do {} while (0) 1391 #define BUFFER_TRACE2(bh, bh2, info) do {} while (0) 1392 #define JBUFFER_TRACE(jh, info) do {} while (0) 1393 1394 #endif /* __KERNEL__ */ 1395 1396 #endif /* _LINUX_JBD2_H */ 1397