include/linux/jbd.h

   1 /*
   2  * linux/include/linux/jbd.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_JBD_H
  17 #define _LINUX_JBD_H
  18
  19 /* Allow this file to be included directly into e2fsprogs */
  20 #ifndef __KERNEL__
  21 #include "jfs_compat.h"
  22 #define JFS_DEBUG
  23 #define jfs_debug jbd_debug
  24 #else
  25
  26 #include <linux/types.h>
  27 #include <linux/buffer_head.h>
  28 #include <linux/journal-head.h>
  29 #include <linux/stddef.h>
  30 #include <linux/bit_spinlock.h>
  31 #include <linux/mutex.h>
  32 #include <linux/timer.h>
  33 #include <linux/lockdep.h>
  34 #include <linux/slab.h>
  35
  36 #define journal_oom_retry 1
  37
  38 /*
  39  * Define JBD_PARANOID_IOFAIL to cause a kernel BUG() if ext3 finds
  40  * certain classes of error which can occur due to failed IOs.  Under
  41  * normal use we want ext3 to continue after such errors, because
  42  * hardware _can_ fail, but for debugging purposes when running tests on
  43  * known-good hardware we may want to trap these errors.
  44  */
  45 #undef JBD_PARANOID_IOFAIL
  46
  47 /*
  48  * The default maximum commit age, in seconds.
  49  */
  50 #define JBD_DEFAULT_MAX_COMMIT_AGE 5
  51
  52 #ifdef CONFIG_JBD_DEBUG
  53 /*
  54  * Define JBD_EXPENSIVE_CHECKING to enable more expensive internal
  55  * consistency checks.  By default we don't do this unless
  56  * CONFIG_JBD_DEBUG is on.
  57  */
  58 #define JBD_EXPENSIVE_CHECKING
  59 extern u8 journal_enable_debug;
  60
  61 #define jbd_debug(n, f, a...)                                           \
  62         do {                                                            \
  63                 if ((n) <= journal_enable_debug) {                      \
  64                         printk (KERN_DEBUG "(%s, %d): %s: ",            \
  65                                 __FILE__, __LINE__, __func__);  \
  66                         printk (f, ## a);                               \
  67                 }                                                       \
  68         } while (0)
  69 #else
  70 #define jbd_debug(f, a...)      /**/
  71 #endif
  72
  73 static inline void *jbd_alloc(size_t size, gfp_t flags)
  74 {
  75         return (void *)__get_free_pages(flags, get_order(size));
  76 }
  77
  78 static inline void jbd_free(void *ptr, size_t size)
  79 {
  80         free_pages((unsigned long)ptr, get_order(size));
  81 };
  82
  83 #define JFS_MIN_JOURNAL_BLOCKS 1024
  84
  85
  86 /**
  87  * typedef handle_t - The handle_t type represents a single atomic update being performed by some process.
  88  *
  89  * All filesystem modifications made by the process go
  90  * through this handle.  Recursive operations (such as quota operations)
  91  * are gathered into a single update.
  92  *
  93  * The buffer credits field is used to account for journaled buffers
  94  * being modified by the running process.  To ensure that there is
  95  * enough log space for all outstanding operations, we need to limit the
  96  * number of outstanding buffers possible at any time.  When the
  97  * operation completes, any buffer credits not used are credited back to
  98  * the transaction, so that at all times we know how many buffers the
  99  * outstanding updates on a transaction might possibly touch.
 100  *
 101  * This is an opaque datatype.
 102  **/
 103 typedef struct handle_s         handle_t;       /* Atomic operation type */
 104
 105
 106 /**
 107  * typedef journal_t - The journal_t maintains all of the journaling state information for a single filesystem.
 108  *
 109  * journal_t is linked to from the fs superblock structure.
 110  *
 111  * We use the journal_t to keep track of all outstanding transaction
 112  * activity on the filesystem, and to manage the state of the log
 113  * writing process.
 114  *
 115  * This is an opaque datatype.
 116  **/
 117 typedef struct journal_s        journal_t;      /* Journal control structure */
 118 #endif
 119
 120 /*
 121  * Internal structures used by the logging mechanism:
 122  */
 123
 124 #define JFS_MAGIC_NUMBER 0xc03b3998U /* The first 4 bytes of /dev/random! */
 125
 126 /*
 127  * On-disk structures
 128  */
 129
 130 /*
 131  * Descriptor block types:
 132  */
 133
 134 #define JFS_DESCRIPTOR_BLOCK    1
 135 #define JFS_COMMIT_BLOCK        2
 136 #define JFS_SUPERBLOCK_V1       3
 137 #define JFS_SUPERBLOCK_V2       4
 138 #define JFS_REVOKE_BLOCK        5
 139
 140 /*
 141  * Standard header for all descriptor blocks:
 142  */
 143 typedef struct journal_header_s
 144 {
 145         __be32          h_magic;
 146         __be32          h_blocktype;
 147         __be32          h_sequence;
 148 } journal_header_t;
 149
 150
 151 /*
 152  * The block tag: used to describe a single buffer in the journal
 153  */
 154 typedef struct journal_block_tag_s
 155 {
 156         __be32          t_blocknr;      /* The on-disk block number */
 157         __be32          t_flags;        /* See below */
 158 } journal_block_tag_t;
 159
 160 /*
 161  * The revoke descriptor: used on disk to describe a series of blocks to
 162  * be revoked from the log
 163  */
 164 typedef struct journal_revoke_header_s
 165 {
 166         journal_header_t r_header;
 167         __be32           r_count;       /* Count of bytes used in the block */
 168 } journal_revoke_header_t;
 169
 170
 171 /* Definitions for the journal tag flags word: */
 172 #define JFS_FLAG_ESCAPE         1       /* on-disk block is escaped */
 173 #define JFS_FLAG_SAME_UUID      2       /* block has same uuid as previous */
 174 #define JFS_FLAG_DELETED        4       /* block deleted by this transaction */
 175 #define JFS_FLAG_LAST_TAG       8       /* last tag in this descriptor block */
 176
 177
 178 /*
 179  * The journal superblock.  All fields are in big-endian byte order.
 180  */
 181 typedef struct journal_superblock_s
 182 {
 183 /* 0x0000 */
 184         journal_header_t s_header;
 185
 186 /* 0x000C */
 187         /* Static information describing the journal */
 188         __be32  s_blocksize;            /* journal device blocksize */
 189         __be32  s_maxlen;               /* total blocks in journal file */
 190         __be32  s_first;                /* first block of log information */
 191
 192 /* 0x0018 */
 193         /* Dynamic information describing the current state of the log */
 194         __be32  s_sequence;             /* first commit ID expected in log */
 195         __be32  s_start;                /* blocknr of start of log */
 196
 197 /* 0x0020 */
 198         /* Error value, as set by journal_abort(). */
 199         __be32  s_errno;
 200
 201 /* 0x0024 */
 202         /* Remaining fields are only valid in a version-2 superblock */
 203         __be32  s_feature_compat;       /* compatible feature set */
 204         __be32  s_feature_incompat;     /* incompatible feature set */
 205         __be32  s_feature_ro_compat;    /* readonly-compatible feature set */
 206 /* 0x0030 */
 207         __u8    s_uuid[16];             /* 128-bit uuid for journal */
 208
 209 /* 0x0040 */
 210         __be32  s_nr_users;             /* Nr of filesystems sharing log */
 211
 212         __be32  s_dynsuper;             /* Blocknr of dynamic superblock copy*/
 213
 214 /* 0x0048 */
 215         __be32  s_max_transaction;      /* Limit of journal blocks per trans.*/
 216         __be32  s_max_trans_data;       /* Limit of data blocks per trans. */
 217
 218 /* 0x0050 */
 219         __u32   s_padding[44];
 220
 221 /* 0x0100 */
 222         __u8    s_users[16*48];         /* ids of all fs'es sharing the log */
 223 /* 0x0400 */
 224 } journal_superblock_t;
 225
 226 #define JFS_HAS_COMPAT_FEATURE(j,mask)                                  \
 227         ((j)->j_format_version >= 2 &&                                  \
 228          ((j)->j_superblock->s_feature_compat & cpu_to_be32((mask))))
 229 #define JFS_HAS_RO_COMPAT_FEATURE(j,mask)                               \
 230         ((j)->j_format_version >= 2 &&                                  \
 231          ((j)->j_superblock->s_feature_ro_compat & cpu_to_be32((mask))))
 232 #define JFS_HAS_INCOMPAT_FEATURE(j,mask)                                \
 233         ((j)->j_format_version >= 2 &&                                  \
 234          ((j)->j_superblock->s_feature_incompat & cpu_to_be32((mask))))
 235
 236 #define JFS_FEATURE_INCOMPAT_REVOKE     0x00000001
 237
 238 /* Features known to this kernel version: */
 239 #define JFS_KNOWN_COMPAT_FEATURES       0
 240 #define JFS_KNOWN_ROCOMPAT_FEATURES     0
 241 #define JFS_KNOWN_INCOMPAT_FEATURES     JFS_FEATURE_INCOMPAT_REVOKE
 242
 243 #ifdef __KERNEL__
 244
 245 #include <linux/fs.h>
 246 #include <linux/sched.h>
 247
 248 #define J_ASSERT(assert)        BUG_ON(!(assert))
 249
 250 #define J_ASSERT_BH(bh, expr)   J_ASSERT(expr)
 251 #define J_ASSERT_JH(jh, expr)   J_ASSERT(expr)
 252
 253 #if defined(JBD_PARANOID_IOFAIL)
 254 #define J_EXPECT(expr, why...)          J_ASSERT(expr)
 255 #define J_EXPECT_BH(bh, expr, why...)   J_ASSERT_BH(bh, expr)
 256 #define J_EXPECT_JH(jh, expr, why...)   J_ASSERT_JH(jh, expr)
 257 #else
 258 #define __journal_expect(expr, why...)                                       \
 259         ({                                                                   \
 260                 int val = (expr);                                            \
 261                 if (!val) {                                                  \
 262                         printk(KERN_ERR                                      \
 263                                 "EXT3-fs unexpected failure: %s;\n",# expr); \
 264                         printk(KERN_ERR why "\n");                           \
 265                 }                                                            \
 266                 val;                                                         \
 267         })
 268 #define J_EXPECT(expr, why...)          __journal_expect(expr, ## why)
 269 #define J_EXPECT_BH(bh, expr, why...)   __journal_expect(expr, ## why)
 270 #define J_EXPECT_JH(jh, expr, why...)   __journal_expect(expr, ## why)
 271 #endif
 272
 273 enum jbd_state_bits {
 274         BH_JBD                  /* Has an attached ext3 journal_head */
 275           = BH_PrivateStart,
 276         BH_JWrite,              /* Being written to log (@@@ DEBUGGING) */
 277         BH_Freed,               /* Has been freed (truncated) */
 278         BH_Revoked,             /* Has been revoked from the log */
 279         BH_RevokeValid,         /* Revoked flag is valid */
 280         BH_JBDDirty,            /* Is dirty but journaled */
 281         BH_State,               /* Pins most journal_head state */
 282         BH_JournalHead,         /* Pins bh->b_private and jh->b_bh */
 283         BH_Unshadow,            /* Dummy bit, for BJ_Shadow wakeup filtering */
 284 };
 285
 286 BUFFER_FNS(JBD, jbd)
 287 BUFFER_FNS(JWrite, jwrite)
 288 BUFFER_FNS(JBDDirty, jbddirty)
 289 TAS_BUFFER_FNS(JBDDirty, jbddirty)
 290 BUFFER_FNS(Revoked, revoked)
 291 TAS_BUFFER_FNS(Revoked, revoked)
 292 BUFFER_FNS(RevokeValid, revokevalid)
 293 TAS_BUFFER_FNS(RevokeValid, revokevalid)
 294 BUFFER_FNS(Freed, freed)
 295
 296 static inline struct buffer_head *jh2bh(struct journal_head *jh)
 297 {
 298         return jh->b_bh;
 299 }
 300
 301 static inline struct journal_head *bh2jh(struct buffer_head *bh)
 302 {
 303         return bh->b_private;
 304 }
 305
 306 static inline void jbd_lock_bh_state(struct buffer_head *bh)
 307 {
 308         bit_spin_lock(BH_State, &bh->b_state);
 309 }
 310
 311 static inline int jbd_trylock_bh_state(struct buffer_head *bh)
 312 {
 313         return bit_spin_trylock(BH_State, &bh->b_state);
 314 }
 315
 316 static inline int jbd_is_locked_bh_state(struct buffer_head *bh)
 317 {
 318         return bit_spin_is_locked(BH_State, &bh->b_state);
 319 }
 320
 321 static inline void jbd_unlock_bh_state(struct buffer_head *bh)
 322 {
 323         bit_spin_unlock(BH_State, &bh->b_state);
 324 }
 325
 326 static inline void jbd_lock_bh_journal_head(struct buffer_head *bh)
 327 {
 328         bit_spin_lock(BH_JournalHead, &bh->b_state);
 329 }
 330
 331 static inline void jbd_unlock_bh_journal_head(struct buffer_head *bh)
 332 {
 333         bit_spin_unlock(BH_JournalHead, &bh->b_state);
 334 }
 335
 336 struct jbd_revoke_table_s;
 337
 338 /**
 339  * struct handle_s - this is the concrete type associated with handle_t.
 340  * @h_transaction: Which compound transaction is this update a part of?
 341  * @h_buffer_credits: Number of remaining buffers we are allowed to dirty.
 342  * @h_ref: Reference count on this handle
 343  * @h_err: Field for caller's use to track errors through large fs operations
 344  * @h_sync: flag for sync-on-close
 345  * @h_jdata: flag to force data journaling
 346  * @h_aborted: flag indicating fatal error on handle
 347  * @h_lockdep_map: lockdep info for debugging lock problems
 348  */
 349 struct handle_s
 350 {
 351         /* Which compound transaction is this update a part of? */
 352         transaction_t           *h_transaction;
 353
 354         /* Number of remaining buffers we are allowed to dirty: */
 355         int                     h_buffer_credits;
 356
 357         /* Reference count on this handle */
 358         int                     h_ref;
 359
 360         /* Field for caller's use to track errors through large fs */
 361         /* operations */
 362         int                     h_err;
 363
 364         /* Flags [no locking] */
 365         unsigned int    h_sync:         1;      /* sync-on-close */
 366         unsigned int    h_jdata:        1;      /* force data journaling */
 367         unsigned int    h_aborted:      1;      /* fatal error on handle */
 368
 369 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 370         struct lockdep_map      h_lockdep_map;
 371 #endif
 372 };
 373
 374
 375 /* The transaction_t type is the guts of the journaling mechanism.  It
 376  * tracks a compound transaction through its various states:
 377  *
 378  * RUNNING:     accepting new updates
 379  * LOCKED:      Updates still running but we don't accept new ones
 380  * RUNDOWN:     Updates are tidying up but have finished requesting
 381  *              new buffers to modify (state not used for now)
 382  * FLUSH:       All updates complete, but we are still writing to disk
 383  * COMMIT:      All data on disk, writing commit record
 384  * FINISHED:    We still have to keep the transaction for checkpointing.
 385  *
 386  * The transaction keeps track of all of the buffers modified by a
 387  * running transaction, and all of the buffers committed but not yet
 388  * flushed to home for finished transactions.
 389  */
 390
 391 /*
 392  * Lock ranking:
 393  *
 394  *    j_list_lock
 395  *      ->jbd_lock_bh_journal_head()    (This is "innermost")
 396  *
 397  *    j_state_lock
 398  *    ->jbd_lock_bh_state()
 399  *
 400  *    jbd_lock_bh_state()
 401  *    ->j_list_lock
 402  *
 403  *    j_state_lock
 404  *    ->t_handle_lock
 405  *
 406  *    j_state_lock
 407  *    ->j_list_lock                     (journal_unmap_buffer)
 408  *
 409  */
 410
 411 struct transaction_s
 412 {
 413         /* Pointer to the journal for this transaction. [no locking] */
 414         journal_t               *t_journal;
 415
 416         /* Sequence number for this transaction [no locking] */
 417         tid_t                   t_tid;
 418
 419         /*
 420          * Transaction's current state
 421          * [no locking - only kjournald alters this]
 422          * [j_list_lock] guards transition of a transaction into T_FINISHED
 423          * state and subsequent call of __journal_drop_transaction()
 424          * FIXME: needs barriers
 425          * KLUDGE: [use j_state_lock]
 426          */
 427         enum {
 428                 T_RUNNING,
 429                 T_LOCKED,
 430                 T_RUNDOWN,
 431                 T_FLUSH,
 432                 T_COMMIT,
 433                 T_FINISHED
 434         }                       t_state;
 435
 436         /*
 437          * Where in the log does this transaction's commit start? [no locking]
 438          */
 439         unsigned int            t_log_start;
 440
 441         /* Number of buffers on the t_buffers list [j_list_lock] */
 442         int                     t_nr_buffers;
 443
 444         /*
 445          * Doubly-linked circular list of all buffers reserved but not yet
 446          * modified by this transaction [j_list_lock]
 447          */
 448         struct journal_head     *t_reserved_list;
 449
 450         /*
 451          * Doubly-linked circular list of all buffers under writeout during
 452          * commit [j_list_lock]
 453          */
 454         struct journal_head     *t_locked_list;
 455
 456         /*
 457          * Doubly-linked circular list of all metadata buffers owned by this
 458          * transaction [j_list_lock]
 459          */
 460         struct journal_head     *t_buffers;
 461
 462         /*
 463          * Doubly-linked circular list of all data buffers still to be
 464          * flushed before this transaction can be committed [j_list_lock]
 465          */
 466         struct journal_head     *t_sync_datalist;
 467
 468         /*
 469          * Doubly-linked circular list of all forget buffers (superseded
 470          * buffers which we can un-checkpoint once this transaction commits)
 471          * [j_list_lock]
 472          */
 473         struct journal_head     *t_forget;
 474
 475         /*
 476          * Doubly-linked circular list of all buffers still to be flushed before
 477          * this transaction can be checkpointed. [j_list_lock]
 478          */
 479         struct journal_head     *t_checkpoint_list;
 480
 481         /*
 482          * Doubly-linked circular list of all buffers submitted for IO while
 483          * checkpointing. [j_list_lock]
 484          */
 485         struct journal_head     *t_checkpoint_io_list;
 486
 487         /*
 488          * Doubly-linked circular list of temporary buffers currently undergoing
 489          * IO in the log [j_list_lock]
 490          */
 491         struct journal_head     *t_iobuf_list;
 492
 493         /*
 494          * Doubly-linked circular list of metadata buffers being shadowed by log
 495          * IO.  The IO buffers on the iobuf list and the shadow buffers on this
 496          * list match each other one for one at all times. [j_list_lock]
 497          */
 498         struct journal_head     *t_shadow_list;
 499
 500         /*
 501          * Doubly-linked circular list of control buffers being written to the
 502          * log. [j_list_lock]
 503          */
 504         struct journal_head     *t_log_list;
 505
 506         /*
 507          * Protects info related to handles
 508          */
 509         spinlock_t              t_handle_lock;
 510
 511         /*
 512          * Number of outstanding updates running on this transaction
 513          * [t_handle_lock]
 514          */
 515         int                     t_updates;
 516
 517         /*
 518          * Number of buffers reserved for use by all handles in this transaction
 519          * handle but not yet modified. [t_handle_lock]
 520          */
 521         int                     t_outstanding_credits;
 522
 523         /*
 524          * Forward and backward links for the circular list of all transactions
 525          * awaiting checkpoint. [j_list_lock]
 526          */
 527         transaction_t           *t_cpnext, *t_cpprev;
 528
 529         /*
 530          * When will the transaction expire (become due for commit), in jiffies?
 531          * [no locking]
 532          */
 533         unsigned long           t_expires;
 534
 535         /*
 536          * When this transaction started, in nanoseconds [no locking]
 537          */
 538         ktime_t                 t_start_time;
 539
 540         /*
 541          * How many handles used this transaction? [t_handle_lock]
 542          */
 543         int t_handle_count;
 544
 545         /*
 546          * This transaction is being forced and some process is
 547          * waiting for it to finish.
 548          */
 549         unsigned int t_synchronous_commit:1;
 550 };
 551
 552 /**
 553  * struct journal_s - this is the concrete type associated with journal_t.
 554  * @j_flags:  General journaling state flags
 555  * @j_errno:  Is there an outstanding uncleared error on the journal (from a
 556  *     prior abort)?
 557  * @j_sb_buffer: First part of superblock buffer
 558  * @j_superblock: Second part of superblock buffer
 559  * @j_format_version: Version of the superblock format
 560  * @j_state_lock: Protect the various scalars in the journal
 561  * @j_barrier_count:  Number of processes waiting to create a barrier lock
 562  * @j_barrier: The barrier lock itself
 563  * @j_running_transaction: The current running transaction..
 564  * @j_committing_transaction: the transaction we are pushing to disk
 565  * @j_checkpoint_transactions: a linked circular list of all transactions
 566  *  waiting for checkpointing
 567  * @j_wait_transaction_locked: Wait queue for waiting for a locked transaction
 568  *  to start committing, or for a barrier lock to be released
 569  * @j_wait_logspace: Wait queue for waiting for checkpointing to complete
 570  * @j_wait_done_commit: Wait queue for waiting for commit to complete
 571  * @j_wait_checkpoint:  Wait queue to trigger checkpointing
 572  * @j_wait_commit: Wait queue to trigger commit
 573  * @j_wait_updates: Wait queue to wait for updates to complete
 574  * @j_checkpoint_mutex: Mutex for locking against concurrent checkpoints
 575  * @j_head: Journal head - identifies the first unused block in the journal
 576  * @j_tail: Journal tail - identifies the oldest still-used block in the
 577  *  journal.
 578  * @j_free: Journal free - how many free blocks are there in the journal?
 579  * @j_first: The block number of the first usable block
 580  * @j_last: The block number one beyond the last usable block
 581  * @j_dev: Device where we store the journal
 582  * @j_blocksize: blocksize for the location where we store the journal.
 583  * @j_blk_offset: starting block offset for into the device where we store the
 584  *     journal
 585  * @j_fs_dev: Device which holds the client fs.  For internal journal this will
 586  *     be equal to j_dev
 587  * @j_maxlen: Total maximum capacity of the journal region on disk.
 588  * @j_list_lock: Protects the buffer lists and internal buffer state.
 589  * @j_inode: Optional inode where we store the journal.  If present, all journal
 590  *     block numbers are mapped into this inode via bmap().
 591  * @j_tail_sequence:  Sequence number of the oldest transaction in the log
 592  * @j_transaction_sequence: Sequence number of the next transaction to grant
 593  * @j_commit_sequence: Sequence number of the most recently committed
 594  *  transaction
 595  * @j_commit_request: Sequence number of the most recent transaction wanting
 596  *     commit
 597  * @j_uuid: Uuid of client object.
 598  * @j_task: Pointer to the current commit thread for this journal
 599  * @j_max_transaction_buffers:  Maximum number of metadata buffers to allow in a
 600  *     single compound commit transaction
 601  * @j_commit_interval: What is the maximum transaction lifetime before we begin
 602  *  a commit?
 603  * @j_commit_timer:  The timer used to wakeup the commit thread
 604  * @j_revoke_lock: Protect the revoke table
 605  * @j_revoke: The revoke table - maintains the list of revoked blocks in the
 606  *     current transaction.
 607  * @j_revoke_table: alternate revoke tables for j_revoke
 608  * @j_wbuf: array of buffer_heads for journal_commit_transaction
 609  * @j_wbufsize: maximum number of buffer_heads allowed in j_wbuf, the
 610  *      number that will fit in j_blocksize
 611  * @j_last_sync_writer: most recent pid which did a synchronous write
 612  * @j_average_commit_time: the average amount of time in nanoseconds it
 613  *      takes to commit a transaction to the disk.
 614  * @j_private: An opaque pointer to fs-private information.
 615  */
 616
 617 struct journal_s
 618 {
 619         /* General journaling state flags [j_state_lock] */
 620         unsigned long           j_flags;
 621
 622         /*
 623          * Is there an outstanding uncleared error on the journal (from a prior
 624          * abort)? [j_state_lock]
 625          */
 626         int                     j_errno;
 627
 628         /* The superblock buffer */
 629         struct buffer_head      *j_sb_buffer;
 630         journal_superblock_t    *j_superblock;
 631
 632         /* Version of the superblock format */
 633         int                     j_format_version;
 634
 635         /*
 636          * Protect the various scalars in the journal
 637          */
 638         spinlock_t              j_state_lock;
 639
 640         /*
 641          * Number of processes waiting to create a barrier lock [j_state_lock]
 642          */
 643         int                     j_barrier_count;
 644
 645         /* The barrier lock itself */
 646         struct mutex            j_barrier;
 647
 648         /*
 649          * Transactions: The current running transaction...
 650          * [j_state_lock] [caller holding open handle]
 651          */
 652         transaction_t           *j_running_transaction;
 653
 654         /*
 655          * the transaction we are pushing to disk
 656          * [j_state_lock] [caller holding open handle]
 657          */
 658         transaction_t           *j_committing_transaction;
 659
 660         /*
 661          * ... and a linked circular list of all transactions waiting for
 662          * checkpointing. [j_list_lock]
 663          */
 664         transaction_t           *j_checkpoint_transactions;
 665
 666         /*
 667          * Wait queue for waiting for a locked transaction to start committing,
 668          * or for a barrier lock to be released
 669          */
 670         wait_queue_head_t       j_wait_transaction_locked;
 671
 672         /* Wait queue for waiting for checkpointing to complete */
 673         wait_queue_head_t       j_wait_logspace;
 674
 675         /* Wait queue for waiting for commit to complete */
 676         wait_queue_head_t       j_wait_done_commit;
 677
 678         /* Wait queue to trigger checkpointing */
 679         wait_queue_head_t       j_wait_checkpoint;
 680
 681         /* Wait queue to trigger commit */
 682         wait_queue_head_t       j_wait_commit;
 683
 684         /* Wait queue to wait for updates to complete */
 685         wait_queue_head_t       j_wait_updates;
 686
 687         /* Semaphore for locking against concurrent checkpoints */
 688         struct mutex            j_checkpoint_mutex;
 689
 690         /*
 691          * Journal head: identifies the first unused block in the journal.
 692          * [j_state_lock]
 693          */
 694         unsigned int            j_head;
 695
 696         /*
 697          * Journal tail: identifies the oldest still-used block in the journal.
 698          * [j_state_lock]
 699          */
 700         unsigned int            j_tail;
 701
 702         /*
 703          * Journal free: how many free blocks are there in the journal?
 704          * [j_state_lock]
 705          */
 706         unsigned int            j_free;
 707
 708         /*
 709          * Journal start and end: the block numbers of the first usable block
 710          * and one beyond the last usable block in the journal. [j_state_lock]
 711          */
 712         unsigned int            j_first;
 713         unsigned int            j_last;
 714
 715         /*
 716          * Device, blocksize and starting block offset for the location where we
 717          * store the journal.
 718          */
 719         struct block_device     *j_dev;
 720         int                     j_blocksize;
 721         unsigned int            j_blk_offset;
 722
 723         /*
 724          * Device which holds the client fs.  For internal journal this will be
 725          * equal to j_dev.
 726          */
 727         struct block_device     *j_fs_dev;
 728
 729         /* Total maximum capacity of the journal region on disk. */
 730         unsigned int            j_maxlen;
 731
 732         /*
 733          * Protects the buffer lists and internal buffer state.
 734          */
 735         spinlock_t              j_list_lock;
 736
 737         /* Optional inode where we store the journal.  If present, all */
 738         /* journal block numbers are mapped into this inode via */
 739         /* bmap(). */
 740         struct inode            *j_inode;
 741
 742         /*
 743          * Sequence number of the oldest transaction in the log [j_state_lock]
 744          */
 745         tid_t                   j_tail_sequence;
 746
 747         /*
 748          * Sequence number of the next transaction to grant [j_state_lock]
 749          */
 750         tid_t                   j_transaction_sequence;
 751
 752         /*
 753          * Sequence number of the most recently committed transaction
 754          * [j_state_lock].
 755          */
 756         tid_t                   j_commit_sequence;
 757
 758         /*
 759          * Sequence number of the most recent transaction wanting commit
 760          * [j_state_lock]
 761          */
 762         tid_t                   j_commit_request;
 763
 764         /*
 765          * Journal uuid: identifies the object (filesystem, LVM volume etc)
 766          * backed by this journal.  This will eventually be replaced by an array
 767          * of uuids, allowing us to index multiple devices within a single
 768          * journal and to perform atomic updates across them.
 769          */
 770         __u8                    j_uuid[16];
 771
 772         /* Pointer to the current commit thread for this journal */
 773         struct task_struct      *j_task;
 774
 775         /*
 776          * Maximum number of metadata buffers to allow in a single compound
 777          * commit transaction
 778          */
 779         int                     j_max_transaction_buffers;
 780
 781         /*
 782          * What is the maximum transaction lifetime before we begin a commit?
 783          */
 784         unsigned long           j_commit_interval;
 785
 786         /* The timer used to wakeup the commit thread: */
 787         struct timer_list       j_commit_timer;
 788
 789         /*
 790          * The revoke table: maintains the list of revoked blocks in the
 791          * current transaction.  [j_revoke_lock]
 792          */
 793         spinlock_t              j_revoke_lock;
 794         struct jbd_revoke_table_s *j_revoke;
 795         struct jbd_revoke_table_s *j_revoke_table[2];
 796
 797         /*
 798          * array of bhs for journal_commit_transaction
 799          */
 800         struct buffer_head      **j_wbuf;
 801         int                     j_wbufsize;
 802
 803         /*
 804          * this is the pid of the last person to run a synchronous operation
 805          * through the journal.
 806          */
 807         pid_t                   j_last_sync_writer;
 808
 809         /*
 810          * the average amount of time in nanoseconds it takes to commit a
 811          * transaction to the disk.  [j_state_lock]
 812          */
 813         u64                     j_average_commit_time;
 814
 815         /*
 816          * An opaque pointer to fs-private information.  ext3 puts its
 817          * superblock pointer here
 818          */
 819         void *j_private;
 820 };
 821
 822 /*
 823  * Journal flag definitions
 824  */
 825 #define JFS_UNMOUNT     0x001   /* Journal thread is being destroyed */
 826 #define JFS_ABORT       0x002   /* Journaling has been aborted for errors. */
 827 #define JFS_ACK_ERR     0x004   /* The errno in the sb has been acked */
 828 #define JFS_FLUSHED     0x008   /* The journal superblock has been flushed */
 829 #define JFS_LOADED      0x010   /* The journal superblock has been loaded */
 830 #define JFS_BARRIER     0x020   /* Use IDE barriers */
 831 #define JFS_ABORT_ON_SYNCDATA_ERR       0x040  /* Abort the journal on file
 832                                                 * data write error in ordered
 833                                                 * mode */
 834
 835 /*
 836  * Function declarations for the journaling transaction and buffer
 837  * management
 838  */
 839
 840 /* Filing buffers */
 841 extern void journal_unfile_buffer(journal_t *, struct journal_head *);
 842 extern void __journal_unfile_buffer(struct journal_head *);
 843 extern void __journal_refile_buffer(struct journal_head *);
 844 extern void journal_refile_buffer(journal_t *, struct journal_head *);
 845 extern void __journal_file_buffer(struct journal_head *, transaction_t *, int);
 846 extern void __journal_free_buffer(struct journal_head *bh);
 847 extern void journal_file_buffer(struct journal_head *, transaction_t *, int);
 848 extern void __journal_clean_data_list(transaction_t *transaction);
 849
 850 /* Log buffer allocation */
 851 extern struct journal_head * journal_get_descriptor_buffer(journal_t *);
 852 int journal_next_log_block(journal_t *, unsigned int *);
 853
 854 /* Commit management */
 855 extern void journal_commit_transaction(journal_t *);
 856
 857 /* Checkpoint list management */
 858 int __journal_clean_checkpoint_list(journal_t *journal);
 859 int __journal_remove_checkpoint(struct journal_head *);
 860 void __journal_insert_checkpoint(struct journal_head *, transaction_t *);
 861
 862 /* Buffer IO */
 863 extern int
 864 journal_write_metadata_buffer(transaction_t       *transaction,
 865                               struct journal_head  *jh_in,
 866                               struct journal_head **jh_out,
 867                               unsigned int blocknr);
 868
 869 /* Transaction locking */
 870 extern void             __wait_on_journal (journal_t *);
 871
 872 /*
 873  * Journal locking.
 874  *
 875  * We need to lock the journal during transaction state changes so that nobody
 876  * ever tries to take a handle on the running transaction while we are in the
 877  * middle of moving it to the commit phase.  j_state_lock does this.
 878  *
 879  * Note that the locking is completely interrupt unsafe.  We never touch
 880  * journal structures from interrupts.
 881  */
 882
 883 static inline handle_t *journal_current_handle(void)
 884 {
 885         return current->journal_info;
 886 }
 887
 888 /* The journaling code user interface:
 889  *
 890  * Create and destroy handles
 891  * Register buffer modifications against the current transaction.
 892  */
 893
 894 extern handle_t *journal_start(journal_t *, int nblocks);
 895 extern int       journal_restart (handle_t *, int nblocks);
 896 extern int       journal_extend (handle_t *, int nblocks);
 897 extern int       journal_get_write_access(handle_t *, struct buffer_head *);
 898 extern int       journal_get_create_access (handle_t *, struct buffer_head *);
 899 extern int       journal_get_undo_access(handle_t *, struct buffer_head *);
 900 extern int       journal_dirty_data (handle_t *, struct buffer_head *);
 901 extern int       journal_dirty_metadata (handle_t *, struct buffer_head *);
 902 extern void      journal_release_buffer (handle_t *, struct buffer_head *);
 903 extern int       journal_forget (handle_t *, struct buffer_head *);
 904 extern void      journal_sync_buffer (struct buffer_head *);
 905 extern void      journal_invalidatepage(journal_t *,
 906                                 struct page *, unsigned long);
 907 extern int       journal_try_to_free_buffers(journal_t *, struct page *, gfp_t);
 908 extern int       journal_stop(handle_t *);
 909 extern int       journal_flush (journal_t *);
 910 extern void      journal_lock_updates (journal_t *);
 911 extern void      journal_unlock_updates (journal_t *);
 912
 913 extern journal_t * journal_init_dev(struct block_device *bdev,
 914                                 struct block_device *fs_dev,
 915                                 int start, int len, int bsize);
 916 extern journal_t * journal_init_inode (struct inode *);
 917 extern int         journal_update_format (journal_t *);
 918 extern int         journal_check_used_features
 919                    (journal_t *, unsigned long, unsigned long, unsigned long);
 920 extern int         journal_check_available_features
 921                    (journal_t *, unsigned long, unsigned long, unsigned long);
 922 extern int         journal_set_features
 923                    (journal_t *, unsigned long, unsigned long, unsigned long);
 924 extern int         journal_create     (journal_t *);
 925 extern int         journal_load       (journal_t *journal);
 926 extern int         journal_destroy    (journal_t *);
 927 extern int         journal_recover    (journal_t *journal);
 928 extern int         journal_wipe       (journal_t *, int);
 929 extern int         journal_skip_recovery        (journal_t *);
 930 extern void        journal_update_superblock    (journal_t *, int);
 931 extern void        journal_abort      (journal_t *, int);
 932 extern int         journal_errno      (journal_t *);
 933 extern void        journal_ack_err    (journal_t *);
 934 extern int         journal_clear_err  (journal_t *);
 935 extern int         journal_bmap(journal_t *, unsigned int, unsigned int *);
 936 extern int         journal_force_commit(journal_t *);
 937
 938 /*
 939  * journal_head management
 940  */
 941 struct journal_head *journal_add_journal_head(struct buffer_head *bh);
 942 struct journal_head *journal_grab_journal_head(struct buffer_head *bh);
 943 void journal_remove_journal_head(struct buffer_head *bh);
 944 void journal_put_journal_head(struct journal_head *jh);
 945
 946 /*
 947  * handle management
 948  */
 949 extern struct kmem_cache *jbd_handle_cache;
 950
 951 static inline handle_t *jbd_alloc_handle(gfp_t gfp_flags)
 952 {
 953         return kmem_cache_alloc(jbd_handle_cache, gfp_flags);
 954 }
 955
 956 static inline void jbd_free_handle(handle_t *handle)
 957 {
 958         kmem_cache_free(jbd_handle_cache, handle);
 959 }
 960
 961 /* Primary revoke support */
 962 #define JOURNAL_REVOKE_DEFAULT_HASH 256
 963 extern int         journal_init_revoke(journal_t *, int);
 964 extern void        journal_destroy_revoke_caches(void);
 965 extern int         journal_init_revoke_caches(void);
 966
 967 extern void        journal_destroy_revoke(journal_t *);
 968 extern int         journal_revoke (handle_t *,
 969                                 unsigned int, struct buffer_head *);
 970 extern int         journal_cancel_revoke(handle_t *, struct journal_head *);
 971 extern void        journal_write_revoke_records(journal_t *,
 972                                                 transaction_t *, int);
 973
 974 /* Recovery revoke support */
 975 extern int      journal_set_revoke(journal_t *, unsigned int, tid_t);
 976 extern int      journal_test_revoke(journal_t *, unsigned int, tid_t);
 977 extern void     journal_clear_revoke(journal_t *);
 978 extern void     journal_switch_revoke_table(journal_t *journal);
 979
 980 /*
 981  * The log thread user interface:
 982  *
 983  * Request space in the current transaction, and force transaction commit
 984  * transitions on demand.
 985  */
 986
 987 int __log_space_left(journal_t *); /* Called with journal locked */
 988 int log_start_commit(journal_t *journal, tid_t tid);
 989 int __log_start_commit(journal_t *journal, tid_t tid);
 990 int journal_start_commit(journal_t *journal, tid_t *tid);
 991 int journal_force_commit_nested(journal_t *journal);
 992 int log_wait_commit(journal_t *journal, tid_t tid);
 993 int log_do_checkpoint(journal_t *journal);
 994
 995 void __log_wait_for_space(journal_t *journal);
 996 extern void     __journal_drop_transaction(journal_t *, transaction_t *);
 997 extern int      cleanup_journal_tail(journal_t *);
 998
 999 /* Debugging code only: */
1000
1001 #define jbd_ENOSYS() \
1002 do {                                                                       \
1003         printk (KERN_ERR "JBD unimplemented function %s\n", __func__); \
1004         current->state = TASK_UNINTERRUPTIBLE;                             \
1005         schedule();                                                        \
1006 } while (1)
1007
1008 /*
1009  * is_journal_abort
1010  *
1011  * Simple test wrapper function to test the JFS_ABORT state flag.  This
1012  * bit, when set, indicates that we have had a fatal error somewhere,
1013  * either inside the journaling layer or indicated to us by the client
1014  * (eg. ext3), and that we and should not commit any further
1015  * transactions.
1016  */
1017
1018 static inline int is_journal_aborted(journal_t *journal)
1019 {
1020         return journal->j_flags & JFS_ABORT;
1021 }
1022
1023 static inline int is_handle_aborted(handle_t *handle)
1024 {
1025         if (handle->h_aborted)
1026                 return 1;
1027         return is_journal_aborted(handle->h_transaction->t_journal);
1028 }
1029
1030 static inline void journal_abort_handle(handle_t *handle)
1031 {
1032         handle->h_aborted = 1;
1033 }
1034
1035 #endif /* __KERNEL__   */
1036
1037 /* Comparison functions for transaction IDs: perform comparisons using
1038  * modulo arithmetic so that they work over sequence number wraps. */
1039
1040 static inline int tid_gt(tid_t x, tid_t y)
1041 {
1042         int difference = (x - y);
1043         return (difference > 0);
1044 }
1045
1046 static inline int tid_geq(tid_t x, tid_t y)
1047 {
1048         int difference = (x - y);
1049         return (difference >= 0);
1050 }
1051
1052 extern int journal_blocks_per_page(struct inode *inode);
1053
1054 /*
1055  * Return the minimum number of blocks which must be free in the journal
1056  * before a new transaction may be started.  Must be called under j_state_lock.
1057  */
1058 static inline int jbd_space_needed(journal_t *journal)
1059 {
1060         int nblocks = journal->j_max_transaction_buffers;
1061         if (journal->j_committing_transaction)
1062                 nblocks += journal->j_committing_transaction->
1063                                         t_outstanding_credits;
1064         return nblocks;
1065 }
1066
1067 /*
1068  * Definitions which augment the buffer_head layer
1069  */
1070
1071 /* journaling buffer types */
1072 #define BJ_None         0       /* Not journaled */
1073 #define BJ_SyncData     1       /* Normal data: flush before commit */
1074 #define BJ_Metadata     2       /* Normal journaled metadata */
1075 #define BJ_Forget       3       /* Buffer superseded by this transaction */
1076 #define BJ_IO           4       /* Buffer is for temporary IO use */
1077 #define BJ_Shadow       5       /* Buffer contents being shadowed to the log */
1078 #define BJ_LogCtl       6       /* Buffer contains log descriptors */
1079 #define BJ_Reserved     7       /* Buffer is reserved for access by journal */
1080 #define BJ_Locked       8       /* Locked for I/O during commit */
1081 #define BJ_Types        9
1082
1083 extern int jbd_blocks_per_page(struct inode *inode);
1084
1085 #ifdef __KERNEL__
1086
1087 #define buffer_trace_init(bh)   do {} while (0)
1088 #define print_buffer_fields(bh) do {} while (0)
1089 #define print_buffer_trace(bh)  do {} while (0)
1090 #define BUFFER_TRACE(bh, info)  do {} while (0)
1091 #define BUFFER_TRACE2(bh, bh2, info)    do {} while (0)
1092 #define JBUFFER_TRACE(jh, info) do {} while (0)
1093
1094 #endif  /* __KERNEL__ */
1095
1096 #endif  /* _LINUX_JBD_H */