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