xref: /openbmc/linux/include/linux/jbd2.h (revision 5c480a69)
1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 /*
3  * linux/include/linux/jbd2.h
4  *
5  * Written by Stephen C. Tweedie <sct@redhat.com>
6  *
7  * Copyright 1998-2000 Red Hat, Inc --- All Rights Reserved
8  *
9  * Definitions for transaction data structures for the buffer cache
10  * filesystem journaling support.
11  */
12 
13 #ifndef _LINUX_JBD2_H
14 #define _LINUX_JBD2_H
15 
16 /* Allow this file to be included directly into e2fsprogs */
17 #ifndef __KERNEL__
18 #include "jfs_compat.h"
19 #define JBD2_DEBUG
20 #else
21 
22 #include <linux/types.h>
23 #include <linux/buffer_head.h>
24 #include <linux/journal-head.h>
25 #include <linux/stddef.h>
26 #include <linux/mutex.h>
27 #include <linux/timer.h>
28 #include <linux/slab.h>
29 #include <linux/bit_spinlock.h>
30 #include <linux/blkdev.h>
31 #include <crypto/hash.h>
32 #endif
33 
34 #define journal_oom_retry 1
35 
36 /*
37  * Define JBD2_PARANIOD_IOFAIL to cause a kernel BUG() if ext4 finds
38  * certain classes of error which can occur due to failed IOs.  Under
39  * normal use we want ext4 to continue after such errors, because
40  * hardware _can_ fail, but for debugging purposes when running tests on
41  * known-good hardware we may want to trap these errors.
42  */
43 #undef JBD2_PARANOID_IOFAIL
44 
45 /*
46  * The default maximum commit age, in seconds.
47  */
48 #define JBD2_DEFAULT_MAX_COMMIT_AGE 5
49 
50 #ifdef CONFIG_JBD2_DEBUG
51 /*
52  * Define JBD2_EXPENSIVE_CHECKING to enable more expensive internal
53  * consistency checks.  By default we don't do this unless
54  * CONFIG_JBD2_DEBUG is on.
55  */
56 #define JBD2_EXPENSIVE_CHECKING
57 void __jbd2_debug(int level, const char *file, const char *func,
58 		  unsigned int line, const char *fmt, ...);
59 
60 #define jbd2_debug(n, fmt, a...) \
61 	__jbd2_debug((n), __FILE__, __func__, __LINE__, (fmt), ##a)
62 #else
63 #define jbd2_debug(n, fmt, a...)  no_printk(fmt, ##a)
64 #endif
65 
66 extern void *jbd2_alloc(size_t size, gfp_t flags);
67 extern void jbd2_free(void *ptr, size_t size);
68 
69 #define JBD2_MIN_JOURNAL_BLOCKS 1024
70 #define JBD2_DEFAULT_FAST_COMMIT_BLOCKS 256
71 
72 #ifdef __KERNEL__
73 
74 /**
75  * typedef handle_t - The handle_t type represents a single atomic update being performed by some process.
76  *
77  * All filesystem modifications made by the process go
78  * through this handle.  Recursive operations (such as quota operations)
79  * are gathered into a single update.
80  *
81  * The buffer credits field is used to account for journaled buffers
82  * being modified by the running process.  To ensure that there is
83  * enough log space for all outstanding operations, we need to limit the
84  * number of outstanding buffers possible at any time.  When the
85  * operation completes, any buffer credits not used are credited back to
86  * the transaction, so that at all times we know how many buffers the
87  * outstanding updates on a transaction might possibly touch.
88  *
89  * This is an opaque datatype.
90  **/
91 typedef struct jbd2_journal_handle handle_t;	/* Atomic operation type */
92 
93 
94 /**
95  * typedef journal_t - The journal_t maintains all of the journaling state information for a single filesystem.
96  *
97  * journal_t is linked to from the fs superblock structure.
98  *
99  * We use the journal_t to keep track of all outstanding transaction
100  * activity on the filesystem, and to manage the state of the log
101  * writing process.
102  *
103  * This is an opaque datatype.
104  **/
105 typedef struct journal_s	journal_t;	/* Journal control structure */
106 #endif
107 
108 /*
109  * Internal structures used by the logging mechanism:
110  */
111 
112 #define JBD2_MAGIC_NUMBER 0xc03b3998U /* The first 4 bytes of /dev/random! */
113 
114 /*
115  * On-disk structures
116  */
117 
118 /*
119  * Descriptor block types:
120  */
121 
122 #define JBD2_DESCRIPTOR_BLOCK	1
123 #define JBD2_COMMIT_BLOCK	2
124 #define JBD2_SUPERBLOCK_V1	3
125 #define JBD2_SUPERBLOCK_V2	4
126 #define JBD2_REVOKE_BLOCK	5
127 
128 /*
129  * Standard header for all descriptor blocks:
130  */
131 typedef struct journal_header_s
132 {
133 	__be32		h_magic;
134 	__be32		h_blocktype;
135 	__be32		h_sequence;
136 } journal_header_t;
137 
138 /*
139  * Checksum types.
140  */
141 #define JBD2_CRC32_CHKSUM   1
142 #define JBD2_MD5_CHKSUM     2
143 #define JBD2_SHA1_CHKSUM    3
144 #define JBD2_CRC32C_CHKSUM  4
145 
146 #define JBD2_CRC32_CHKSUM_SIZE 4
147 
148 #define JBD2_CHECKSUM_BYTES (32 / sizeof(u32))
149 /*
150  * Commit block header for storing transactional checksums:
151  *
152  * NOTE: If FEATURE_COMPAT_CHECKSUM (checksum v1) is set, the h_chksum*
153  * fields are used to store a checksum of the descriptor and data blocks.
154  *
155  * If FEATURE_INCOMPAT_CSUM_V2 (checksum v2) is set, then the h_chksum
156  * field is used to store crc32c(uuid+commit_block).  Each journal metadata
157  * block gets its own checksum, and data block checksums are stored in
158  * journal_block_tag (in the descriptor).  The other h_chksum* fields are
159  * not used.
160  *
161  * If FEATURE_INCOMPAT_CSUM_V3 is set, the descriptor block uses
162  * journal_block_tag3_t to store a full 32-bit checksum.  Everything else
163  * is the same as v2.
164  *
165  * Checksum v1, v2, and v3 are mutually exclusive features.
166  */
167 struct commit_header {
168 	__be32		h_magic;
169 	__be32          h_blocktype;
170 	__be32          h_sequence;
171 	unsigned char   h_chksum_type;
172 	unsigned char   h_chksum_size;
173 	unsigned char 	h_padding[2];
174 	__be32 		h_chksum[JBD2_CHECKSUM_BYTES];
175 	__be64		h_commit_sec;
176 	__be32		h_commit_nsec;
177 };
178 
179 /*
180  * The block tag: used to describe a single buffer in the journal.
181  * t_blocknr_high is only used if INCOMPAT_64BIT is set, so this
182  * raw struct shouldn't be used for pointer math or sizeof() - use
183  * journal_tag_bytes(journal) instead to compute this.
184  */
185 typedef struct journal_block_tag3_s
186 {
187 	__be32		t_blocknr;	/* The on-disk block number */
188 	__be32		t_flags;	/* See below */
189 	__be32		t_blocknr_high; /* most-significant high 32bits. */
190 	__be32		t_checksum;	/* crc32c(uuid+seq+block) */
191 } journal_block_tag3_t;
192 
193 typedef struct journal_block_tag_s
194 {
195 	__be32		t_blocknr;	/* The on-disk block number */
196 	__be16		t_checksum;	/* truncated crc32c(uuid+seq+block) */
197 	__be16		t_flags;	/* See below */
198 	__be32		t_blocknr_high; /* most-significant high 32bits. */
199 } journal_block_tag_t;
200 
201 /* Tail of descriptor or revoke block, for checksumming */
202 struct jbd2_journal_block_tail {
203 	__be32		t_checksum;	/* crc32c(uuid+descr_block) */
204 };
205 
206 /*
207  * The revoke descriptor: used on disk to describe a series of blocks to
208  * be revoked from the log
209  */
210 typedef struct jbd2_journal_revoke_header_s
211 {
212 	journal_header_t r_header;
213 	__be32		 r_count;	/* Count of bytes used in the block */
214 } jbd2_journal_revoke_header_t;
215 
216 /* Definitions for the journal tag flags word: */
217 #define JBD2_FLAG_ESCAPE		1	/* on-disk block is escaped */
218 #define JBD2_FLAG_SAME_UUID	2	/* block has same uuid as previous */
219 #define JBD2_FLAG_DELETED	4	/* block deleted by this transaction */
220 #define JBD2_FLAG_LAST_TAG	8	/* last tag in this descriptor block */
221 
222 
223 /*
224  * The journal superblock.  All fields are in big-endian byte order.
225  */
226 typedef struct journal_superblock_s
227 {
228 /* 0x0000 */
229 	journal_header_t s_header;
230 
231 /* 0x000C */
232 	/* Static information describing the journal */
233 	__be32	s_blocksize;		/* journal device blocksize */
234 	__be32	s_maxlen;		/* total blocks in journal file */
235 	__be32	s_first;		/* first block of log information */
236 
237 /* 0x0018 */
238 	/* Dynamic information describing the current state of the log */
239 	__be32	s_sequence;		/* first commit ID expected in log */
240 	__be32	s_start;		/* blocknr of start of log */
241 
242 /* 0x0020 */
243 	/* Error value, as set by jbd2_journal_abort(). */
244 	__be32	s_errno;
245 
246 /* 0x0024 */
247 	/* Remaining fields are only valid in a version-2 superblock */
248 	__be32	s_feature_compat;	/* compatible feature set */
249 	__be32	s_feature_incompat;	/* incompatible feature set */
250 	__be32	s_feature_ro_compat;	/* readonly-compatible feature set */
251 /* 0x0030 */
252 	__u8	s_uuid[16];		/* 128-bit uuid for journal */
253 
254 /* 0x0040 */
255 	__be32	s_nr_users;		/* Nr of filesystems sharing log */
256 
257 	__be32	s_dynsuper;		/* Blocknr of dynamic superblock copy*/
258 
259 /* 0x0048 */
260 	__be32	s_max_transaction;	/* Limit of journal blocks per trans.*/
261 	__be32	s_max_trans_data;	/* Limit of data blocks per trans. */
262 
263 /* 0x0050 */
264 	__u8	s_checksum_type;	/* checksum type */
265 	__u8	s_padding2[3];
266 /* 0x0054 */
267 	__be32	s_num_fc_blks;		/* Number of fast commit blocks */
268 	__be32	s_head;			/* blocknr of head of log, only uptodate
269 					 * while the filesystem is clean */
270 /* 0x005C */
271 	__u32	s_padding[40];
272 	__be32	s_checksum;		/* crc32c(superblock) */
273 
274 /* 0x0100 */
275 	__u8	s_users[16*48];		/* ids of all fs'es sharing the log */
276 /* 0x0400 */
277 } journal_superblock_t;
278 
279 #define JBD2_FEATURE_COMPAT_CHECKSUM		0x00000001
280 
281 #define JBD2_FEATURE_INCOMPAT_REVOKE		0x00000001
282 #define JBD2_FEATURE_INCOMPAT_64BIT		0x00000002
283 #define JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT	0x00000004
284 #define JBD2_FEATURE_INCOMPAT_CSUM_V2		0x00000008
285 #define JBD2_FEATURE_INCOMPAT_CSUM_V3		0x00000010
286 #define JBD2_FEATURE_INCOMPAT_FAST_COMMIT	0x00000020
287 
288 /* See "journal feature predicate functions" below */
289 
290 /* Features known to this kernel version: */
291 #define JBD2_KNOWN_COMPAT_FEATURES	JBD2_FEATURE_COMPAT_CHECKSUM
292 #define JBD2_KNOWN_ROCOMPAT_FEATURES	0
293 #define JBD2_KNOWN_INCOMPAT_FEATURES	(JBD2_FEATURE_INCOMPAT_REVOKE | \
294 					JBD2_FEATURE_INCOMPAT_64BIT | \
295 					JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT | \
296 					JBD2_FEATURE_INCOMPAT_CSUM_V2 | \
297 					JBD2_FEATURE_INCOMPAT_CSUM_V3 | \
298 					JBD2_FEATURE_INCOMPAT_FAST_COMMIT)
299 
300 #ifdef __KERNEL__
301 
302 #include <linux/fs.h>
303 #include <linux/sched.h>
304 
305 enum jbd_state_bits {
306 	BH_JBD			/* Has an attached ext3 journal_head */
307 	  = BH_PrivateStart,
308 	BH_JWrite,		/* Being written to log (@@@ DEBUGGING) */
309 	BH_Freed,		/* Has been freed (truncated) */
310 	BH_Revoked,		/* Has been revoked from the log */
311 	BH_RevokeValid,		/* Revoked flag is valid */
312 	BH_JBDDirty,		/* Is dirty but journaled */
313 	BH_JournalHead,		/* Pins bh->b_private and jh->b_bh */
314 	BH_Shadow,		/* IO on shadow buffer is running */
315 	BH_Verified,		/* Metadata block has been verified ok */
316 	BH_JBDPrivateStart,	/* First bit available for private use by FS */
317 };
318 
BUFFER_FNS(JBD,jbd)319 BUFFER_FNS(JBD, jbd)
320 BUFFER_FNS(JWrite, jwrite)
321 BUFFER_FNS(JBDDirty, jbddirty)
322 TAS_BUFFER_FNS(JBDDirty, jbddirty)
323 BUFFER_FNS(Revoked, revoked)
324 TAS_BUFFER_FNS(Revoked, revoked)
325 BUFFER_FNS(RevokeValid, revokevalid)
326 TAS_BUFFER_FNS(RevokeValid, revokevalid)
327 BUFFER_FNS(Freed, freed)
328 BUFFER_FNS(Shadow, shadow)
329 BUFFER_FNS(Verified, verified)
330 
331 static inline struct buffer_head *jh2bh(struct journal_head *jh)
332 {
333 	return jh->b_bh;
334 }
335 
bh2jh(struct buffer_head * bh)336 static inline struct journal_head *bh2jh(struct buffer_head *bh)
337 {
338 	return bh->b_private;
339 }
340 
jbd_lock_bh_journal_head(struct buffer_head * bh)341 static inline void jbd_lock_bh_journal_head(struct buffer_head *bh)
342 {
343 	bit_spin_lock(BH_JournalHead, &bh->b_state);
344 }
345 
jbd_unlock_bh_journal_head(struct buffer_head * bh)346 static inline void jbd_unlock_bh_journal_head(struct buffer_head *bh)
347 {
348 	bit_spin_unlock(BH_JournalHead, &bh->b_state);
349 }
350 
351 #define J_ASSERT(assert)	BUG_ON(!(assert))
352 
353 #define J_ASSERT_BH(bh, expr)	J_ASSERT(expr)
354 #define J_ASSERT_JH(jh, expr)	J_ASSERT(expr)
355 
356 #if defined(JBD2_PARANOID_IOFAIL)
357 #define J_EXPECT(expr, why...)		J_ASSERT(expr)
358 #define J_EXPECT_BH(bh, expr, why...)	J_ASSERT_BH(bh, expr)
359 #define J_EXPECT_JH(jh, expr, why...)	J_ASSERT_JH(jh, expr)
360 #else
361 #define __journal_expect(expr, why...)					     \
362 	({								     \
363 		int val = (expr);					     \
364 		if (!val) {						     \
365 			printk(KERN_ERR					     \
366 			       "JBD2 unexpected failure: %s: %s;\n",	     \
367 			       __func__, #expr);			     \
368 			printk(KERN_ERR why "\n");			     \
369 		}							     \
370 		val;							     \
371 	})
372 #define J_EXPECT(expr, why...)		__journal_expect(expr, ## why)
373 #define J_EXPECT_BH(bh, expr, why...)	__journal_expect(expr, ## why)
374 #define J_EXPECT_JH(jh, expr, why...)	__journal_expect(expr, ## why)
375 #endif
376 
377 /* Flags in jbd_inode->i_flags */
378 #define __JI_COMMIT_RUNNING 0
379 #define __JI_WRITE_DATA 1
380 #define __JI_WAIT_DATA 2
381 
382 /*
383  * Commit of the inode data in progress. We use this flag to protect us from
384  * concurrent deletion of inode. We cannot use reference to inode for this
385  * since we cannot afford doing last iput() on behalf of kjournald
386  */
387 #define JI_COMMIT_RUNNING (1 << __JI_COMMIT_RUNNING)
388 /* Write allocated dirty buffers in this inode before commit */
389 #define JI_WRITE_DATA (1 << __JI_WRITE_DATA)
390 /* Wait for outstanding data writes for this inode before commit */
391 #define JI_WAIT_DATA (1 << __JI_WAIT_DATA)
392 
393 /**
394  * struct jbd2_inode - The jbd_inode type is the structure linking inodes in
395  * ordered mode present in a transaction so that we can sync them during commit.
396  */
397 struct jbd2_inode {
398 	/**
399 	 * @i_transaction:
400 	 *
401 	 * Which transaction does this inode belong to? Either the running
402 	 * transaction or the committing one. [j_list_lock]
403 	 */
404 	transaction_t *i_transaction;
405 
406 	/**
407 	 * @i_next_transaction:
408 	 *
409 	 * Pointer to the running transaction modifying inode's data in case
410 	 * there is already a committing transaction touching it. [j_list_lock]
411 	 */
412 	transaction_t *i_next_transaction;
413 
414 	/**
415 	 * @i_list: List of inodes in the i_transaction [j_list_lock]
416 	 */
417 	struct list_head i_list;
418 
419 	/**
420 	 * @i_vfs_inode:
421 	 *
422 	 * VFS inode this inode belongs to [constant for lifetime of structure]
423 	 */
424 	struct inode *i_vfs_inode;
425 
426 	/**
427 	 * @i_flags: Flags of inode [j_list_lock]
428 	 */
429 	unsigned long i_flags;
430 
431 	/**
432 	 * @i_dirty_start:
433 	 *
434 	 * Offset in bytes where the dirty range for this inode starts.
435 	 * [j_list_lock]
436 	 */
437 	loff_t i_dirty_start;
438 
439 	/**
440 	 * @i_dirty_end:
441 	 *
442 	 * Inclusive offset in bytes where the dirty range for this inode
443 	 * ends. [j_list_lock]
444 	 */
445 	loff_t i_dirty_end;
446 };
447 
448 struct jbd2_revoke_table_s;
449 
450 /**
451  * struct jbd2_journal_handle - The jbd2_journal_handle type is the concrete
452  *     type associated with handle_t.
453  * @h_transaction: Which compound transaction is this update a part of?
454  * @h_journal: Which journal handle belongs to - used iff h_reserved set.
455  * @h_rsv_handle: Handle reserved for finishing the logical operation.
456  * @h_total_credits: Number of remaining buffers we are allowed to add to
457  *	journal. These are dirty buffers and revoke descriptor blocks.
458  * @h_revoke_credits: Number of remaining revoke records available for handle
459  * @h_ref: Reference count on this handle.
460  * @h_err: Field for caller's use to track errors through large fs operations.
461  * @h_sync: Flag for sync-on-close.
462  * @h_jdata: Flag to force data journaling.
463  * @h_reserved: Flag for handle for reserved credits.
464  * @h_aborted: Flag indicating fatal error on handle.
465  * @h_type: For handle statistics.
466  * @h_line_no: For handle statistics.
467  * @h_start_jiffies: Handle Start time.
468  * @h_requested_credits: Holds @h_total_credits after handle is started.
469  * @h_revoke_credits_requested: Holds @h_revoke_credits after handle is started.
470  * @saved_alloc_context: Saved context while transaction is open.
471  **/
472 
473 /* Docbook can't yet cope with the bit fields, but will leave the documentation
474  * in so it can be fixed later.
475  */
476 
477 struct jbd2_journal_handle
478 {
479 	union {
480 		transaction_t	*h_transaction;
481 		/* Which journal handle belongs to - used iff h_reserved set */
482 		journal_t	*h_journal;
483 	};
484 
485 	handle_t		*h_rsv_handle;
486 	int			h_total_credits;
487 	int			h_revoke_credits;
488 	int			h_revoke_credits_requested;
489 	int			h_ref;
490 	int			h_err;
491 
492 	/* Flags [no locking] */
493 	unsigned int	h_sync:		1;
494 	unsigned int	h_jdata:	1;
495 	unsigned int	h_reserved:	1;
496 	unsigned int	h_aborted:	1;
497 	unsigned int	h_type:		8;
498 	unsigned int	h_line_no:	16;
499 
500 	unsigned long		h_start_jiffies;
501 	unsigned int		h_requested_credits;
502 
503 	unsigned int		saved_alloc_context;
504 };
505 
506 
507 /*
508  * Some stats for checkpoint phase
509  */
510 struct transaction_chp_stats_s {
511 	unsigned long		cs_chp_time;
512 	__u32			cs_forced_to_close;
513 	__u32			cs_written;
514 	__u32			cs_dropped;
515 };
516 
517 /* The transaction_t type is the guts of the journaling mechanism.  It
518  * tracks a compound transaction through its various states:
519  *
520  * RUNNING:	accepting new updates
521  * LOCKED:	Updates still running but we don't accept new ones
522  * RUNDOWN:	Updates are tidying up but have finished requesting
523  *		new buffers to modify (state not used for now)
524  * FLUSH:       All updates complete, but we are still writing to disk
525  * COMMIT:      All data on disk, writing commit record
526  * FINISHED:	We still have to keep the transaction for checkpointing.
527  *
528  * The transaction keeps track of all of the buffers modified by a
529  * running transaction, and all of the buffers committed but not yet
530  * flushed to home for finished transactions.
531  * (Locking Documentation improved by LockDoc)
532  */
533 
534 /*
535  * Lock ranking:
536  *
537  *    j_list_lock
538  *      ->jbd_lock_bh_journal_head()	(This is "innermost")
539  *
540  *    j_state_lock
541  *    ->b_state_lock
542  *
543  *    b_state_lock
544  *    ->j_list_lock
545  *
546  *    j_state_lock
547  *    ->j_list_lock			(journal_unmap_buffer)
548  *
549  */
550 
551 struct transaction_s
552 {
553 	/* Pointer to the journal for this transaction. [no locking] */
554 	journal_t		*t_journal;
555 
556 	/* Sequence number for this transaction [no locking] */
557 	tid_t			t_tid;
558 
559 	/*
560 	 * Transaction's current state
561 	 * [no locking - only kjournald2 alters this]
562 	 * [j_list_lock] guards transition of a transaction into T_FINISHED
563 	 * state and subsequent call of __jbd2_journal_drop_transaction()
564 	 * FIXME: needs barriers
565 	 * KLUDGE: [use j_state_lock]
566 	 */
567 	enum {
568 		T_RUNNING,
569 		T_LOCKED,
570 		T_SWITCH,
571 		T_FLUSH,
572 		T_COMMIT,
573 		T_COMMIT_DFLUSH,
574 		T_COMMIT_JFLUSH,
575 		T_COMMIT_CALLBACK,
576 		T_FINISHED
577 	}			t_state;
578 
579 	/*
580 	 * Where in the log does this transaction's commit start? [no locking]
581 	 */
582 	unsigned long		t_log_start;
583 
584 	/*
585 	 * Number of buffers on the t_buffers list [j_list_lock, no locks
586 	 * needed for jbd2 thread]
587 	 */
588 	int			t_nr_buffers;
589 
590 	/*
591 	 * Doubly-linked circular list of all buffers reserved but not yet
592 	 * modified by this transaction [j_list_lock, no locks needed fo
593 	 * jbd2 thread]
594 	 */
595 	struct journal_head	*t_reserved_list;
596 
597 	/*
598 	 * Doubly-linked circular list of all metadata buffers owned by this
599 	 * transaction [j_list_lock, no locks needed for jbd2 thread]
600 	 */
601 	struct journal_head	*t_buffers;
602 
603 	/*
604 	 * Doubly-linked circular list of all forget buffers (superseded
605 	 * buffers which we can un-checkpoint once this transaction commits)
606 	 * [j_list_lock]
607 	 */
608 	struct journal_head	*t_forget;
609 
610 	/*
611 	 * Doubly-linked circular list of all buffers still to be flushed before
612 	 * this transaction can be checkpointed. [j_list_lock]
613 	 */
614 	struct journal_head	*t_checkpoint_list;
615 
616 	/*
617 	 * Doubly-linked circular list of metadata buffers being
618 	 * shadowed by log IO.  The IO buffers on the iobuf list and
619 	 * the shadow buffers on this list match each other one for
620 	 * one at all times. [j_list_lock, no locks needed for jbd2
621 	 * thread]
622 	 */
623 	struct journal_head	*t_shadow_list;
624 
625 	/*
626 	 * List of inodes associated with the transaction; e.g., ext4 uses
627 	 * this to track inodes in data=ordered and data=journal mode that
628 	 * need special handling on transaction commit; also used by ocfs2.
629 	 * [j_list_lock]
630 	 */
631 	struct list_head	t_inode_list;
632 
633 	/*
634 	 * Longest time some handle had to wait for running transaction
635 	 */
636 	unsigned long		t_max_wait;
637 
638 	/*
639 	 * When transaction started
640 	 */
641 	unsigned long		t_start;
642 
643 	/*
644 	 * When commit was requested [j_state_lock]
645 	 */
646 	unsigned long		t_requested;
647 
648 	/*
649 	 * Checkpointing stats [j_list_lock]
650 	 */
651 	struct transaction_chp_stats_s t_chp_stats;
652 
653 	/*
654 	 * Number of outstanding updates running on this transaction
655 	 * [none]
656 	 */
657 	atomic_t		t_updates;
658 
659 	/*
660 	 * Number of blocks reserved for this transaction in the journal.
661 	 * This is including all credits reserved when starting transaction
662 	 * handles as well as all journal descriptor blocks needed for this
663 	 * transaction. [none]
664 	 */
665 	atomic_t		t_outstanding_credits;
666 
667 	/*
668 	 * Number of revoke records for this transaction added by already
669 	 * stopped handles. [none]
670 	 */
671 	atomic_t		t_outstanding_revokes;
672 
673 	/*
674 	 * How many handles used this transaction? [none]
675 	 */
676 	atomic_t		t_handle_count;
677 
678 	/*
679 	 * Forward and backward links for the circular list of all transactions
680 	 * awaiting checkpoint. [j_list_lock]
681 	 */
682 	transaction_t		*t_cpnext, *t_cpprev;
683 
684 	/*
685 	 * When will the transaction expire (become due for commit), in jiffies?
686 	 * [no locking]
687 	 */
688 	unsigned long		t_expires;
689 
690 	/*
691 	 * When this transaction started, in nanoseconds [no locking]
692 	 */
693 	ktime_t			t_start_time;
694 
695 	/*
696 	 * This transaction is being forced and some process is
697 	 * waiting for it to finish.
698 	 */
699 	unsigned int t_synchronous_commit:1;
700 
701 	/* Disk flush needs to be sent to fs partition [no locking] */
702 	int			t_need_data_flush;
703 
704 	/*
705 	 * For use by the filesystem to store fs-specific data
706 	 * structures associated with the transaction
707 	 */
708 	struct list_head	t_private_list;
709 };
710 
711 struct transaction_run_stats_s {
712 	unsigned long		rs_wait;
713 	unsigned long		rs_request_delay;
714 	unsigned long		rs_running;
715 	unsigned long		rs_locked;
716 	unsigned long		rs_flushing;
717 	unsigned long		rs_logging;
718 
719 	__u32			rs_handle_count;
720 	__u32			rs_blocks;
721 	__u32			rs_blocks_logged;
722 };
723 
724 struct transaction_stats_s {
725 	unsigned long		ts_tid;
726 	unsigned long		ts_requested;
727 	struct transaction_run_stats_s run;
728 };
729 
730 static inline unsigned long
jbd2_time_diff(unsigned long start,unsigned long end)731 jbd2_time_diff(unsigned long start, unsigned long end)
732 {
733 	if (end >= start)
734 		return end - start;
735 
736 	return end + (MAX_JIFFY_OFFSET - start);
737 }
738 
739 #define JBD2_NR_BATCH	64
740 
741 enum passtype {PASS_SCAN, PASS_REVOKE, PASS_REPLAY};
742 
743 #define JBD2_FC_REPLAY_STOP	0
744 #define JBD2_FC_REPLAY_CONTINUE	1
745 
746 /**
747  * struct journal_s - The journal_s type is the concrete type associated with
748  *     journal_t.
749  */
750 struct journal_s
751 {
752 	/**
753 	 * @j_flags: General journaling state flags [j_state_lock,
754 	 * no lock for quick racy checks]
755 	 */
756 	unsigned long		j_flags;
757 
758 	/**
759 	 * @j_atomic_flags: Atomic journaling state flags.
760 	 */
761 	unsigned long		j_atomic_flags;
762 
763 	/**
764 	 * @j_errno:
765 	 *
766 	 * Is there an outstanding uncleared error on the journal (from a prior
767 	 * abort)? [j_state_lock]
768 	 */
769 	int			j_errno;
770 
771 	/**
772 	 * @j_abort_mutex: Lock the whole aborting procedure.
773 	 */
774 	struct mutex		j_abort_mutex;
775 
776 	/**
777 	 * @j_sb_buffer: The first part of the superblock buffer.
778 	 */
779 	struct buffer_head	*j_sb_buffer;
780 
781 	/**
782 	 * @j_superblock: The second part of the superblock buffer.
783 	 */
784 	journal_superblock_t	*j_superblock;
785 
786 	/**
787 	 * @j_state_lock: Protect the various scalars in the journal.
788 	 */
789 	rwlock_t		j_state_lock;
790 
791 	/**
792 	 * @j_barrier_count:
793 	 *
794 	 * Number of processes waiting to create a barrier lock [j_state_lock,
795 	 * no lock for quick racy checks]
796 	 */
797 	int			j_barrier_count;
798 
799 	/**
800 	 * @j_barrier: The barrier lock itself.
801 	 */
802 	struct mutex		j_barrier;
803 
804 	/**
805 	 * @j_running_transaction:
806 	 *
807 	 * Transactions: The current running transaction...
808 	 * [j_state_lock, no lock for quick racy checks] [caller holding
809 	 * open handle]
810 	 */
811 	transaction_t		*j_running_transaction;
812 
813 	/**
814 	 * @j_committing_transaction:
815 	 *
816 	 * the transaction we are pushing to disk
817 	 * [j_state_lock] [caller holding open handle]
818 	 */
819 	transaction_t		*j_committing_transaction;
820 
821 	/**
822 	 * @j_checkpoint_transactions:
823 	 *
824 	 * ... and a linked circular list of all transactions waiting for
825 	 * checkpointing. [j_list_lock]
826 	 */
827 	transaction_t		*j_checkpoint_transactions;
828 
829 	/**
830 	 * @j_wait_transaction_locked:
831 	 *
832 	 * Wait queue for waiting for a locked transaction to start committing,
833 	 * or for a barrier lock to be released.
834 	 */
835 	wait_queue_head_t	j_wait_transaction_locked;
836 
837 	/**
838 	 * @j_wait_done_commit: Wait queue for waiting for commit to complete.
839 	 */
840 	wait_queue_head_t	j_wait_done_commit;
841 
842 	/**
843 	 * @j_wait_commit: Wait queue to trigger commit.
844 	 */
845 	wait_queue_head_t	j_wait_commit;
846 
847 	/**
848 	 * @j_wait_updates: Wait queue to wait for updates to complete.
849 	 */
850 	wait_queue_head_t	j_wait_updates;
851 
852 	/**
853 	 * @j_wait_reserved:
854 	 *
855 	 * Wait queue to wait for reserved buffer credits to drop.
856 	 */
857 	wait_queue_head_t	j_wait_reserved;
858 
859 	/**
860 	 * @j_fc_wait:
861 	 *
862 	 * Wait queue to wait for completion of async fast commits.
863 	 */
864 	wait_queue_head_t	j_fc_wait;
865 
866 	/**
867 	 * @j_checkpoint_mutex:
868 	 *
869 	 * Semaphore for locking against concurrent checkpoints.
870 	 */
871 	struct mutex		j_checkpoint_mutex;
872 
873 	/**
874 	 * @j_chkpt_bhs:
875 	 *
876 	 * List of buffer heads used by the checkpoint routine.  This
877 	 * was moved from jbd2_log_do_checkpoint() to reduce stack
878 	 * usage.  Access to this array is controlled by the
879 	 * @j_checkpoint_mutex.  [j_checkpoint_mutex]
880 	 */
881 	struct buffer_head	*j_chkpt_bhs[JBD2_NR_BATCH];
882 
883 	/**
884 	 * @j_shrinker:
885 	 *
886 	 * Journal head shrinker, reclaim buffer's journal head which
887 	 * has been written back.
888 	 */
889 	struct shrinker		j_shrinker;
890 
891 	/**
892 	 * @j_checkpoint_jh_count:
893 	 *
894 	 * Number of journal buffers on the checkpoint list. [j_list_lock]
895 	 */
896 	struct percpu_counter	j_checkpoint_jh_count;
897 
898 	/**
899 	 * @j_shrink_transaction:
900 	 *
901 	 * Record next transaction will shrink on the checkpoint list.
902 	 * [j_list_lock]
903 	 */
904 	transaction_t		*j_shrink_transaction;
905 
906 	/**
907 	 * @j_head:
908 	 *
909 	 * Journal head: identifies the first unused block in the journal.
910 	 * [j_state_lock]
911 	 */
912 	unsigned long		j_head;
913 
914 	/**
915 	 * @j_tail:
916 	 *
917 	 * Journal tail: identifies the oldest still-used block in the journal.
918 	 * [j_state_lock]
919 	 */
920 	unsigned long		j_tail;
921 
922 	/**
923 	 * @j_free:
924 	 *
925 	 * Journal free: how many free blocks are there in the journal?
926 	 * [j_state_lock]
927 	 */
928 	unsigned long		j_free;
929 
930 	/**
931 	 * @j_first:
932 	 *
933 	 * The block number of the first usable block in the journal
934 	 * [j_state_lock].
935 	 */
936 	unsigned long		j_first;
937 
938 	/**
939 	 * @j_last:
940 	 *
941 	 * The block number one beyond the last usable block in the journal
942 	 * [j_state_lock].
943 	 */
944 	unsigned long		j_last;
945 
946 	/**
947 	 * @j_fc_first:
948 	 *
949 	 * The block number of the first fast commit block in the journal
950 	 * [j_state_lock].
951 	 */
952 	unsigned long		j_fc_first;
953 
954 	/**
955 	 * @j_fc_off:
956 	 *
957 	 * Number of fast commit blocks currently allocated. Accessed only
958 	 * during fast commit. Currently only process can do fast commit, so
959 	 * this field is not protected by any lock.
960 	 */
961 	unsigned long		j_fc_off;
962 
963 	/**
964 	 * @j_fc_last:
965 	 *
966 	 * The block number one beyond the last fast commit block in the journal
967 	 * [j_state_lock].
968 	 */
969 	unsigned long		j_fc_last;
970 
971 	/**
972 	 * @j_dev: Device where we store the journal.
973 	 */
974 	struct block_device	*j_dev;
975 
976 	/**
977 	 * @j_blocksize: Block size for the location where we store the journal.
978 	 */
979 	int			j_blocksize;
980 
981 	/**
982 	 * @j_blk_offset:
983 	 *
984 	 * Starting block offset into the device where we store the journal.
985 	 */
986 	unsigned long long	j_blk_offset;
987 
988 	/**
989 	 * @j_devname: Journal device name.
990 	 */
991 	char			j_devname[BDEVNAME_SIZE+24];
992 
993 	/**
994 	 * @j_fs_dev:
995 	 *
996 	 * Device which holds the client fs.  For internal journal this will be
997 	 * equal to j_dev.
998 	 */
999 	struct block_device	*j_fs_dev;
1000 
1001 	/**
1002 	 * @j_total_len: Total maximum capacity of the journal region on disk.
1003 	 */
1004 	unsigned int		j_total_len;
1005 
1006 	/**
1007 	 * @j_reserved_credits:
1008 	 *
1009 	 * Number of buffers reserved from the running transaction.
1010 	 */
1011 	atomic_t		j_reserved_credits;
1012 
1013 	/**
1014 	 * @j_list_lock: Protects the buffer lists and internal buffer state.
1015 	 */
1016 	spinlock_t		j_list_lock;
1017 
1018 	/**
1019 	 * @j_inode:
1020 	 *
1021 	 * Optional inode where we store the journal.  If present, all
1022 	 * journal block numbers are mapped into this inode via bmap().
1023 	 */
1024 	struct inode		*j_inode;
1025 
1026 	/**
1027 	 * @j_tail_sequence:
1028 	 *
1029 	 * Sequence number of the oldest transaction in the log [j_state_lock]
1030 	 */
1031 	tid_t			j_tail_sequence;
1032 
1033 	/**
1034 	 * @j_transaction_sequence:
1035 	 *
1036 	 * Sequence number of the next transaction to grant [j_state_lock]
1037 	 */
1038 	tid_t			j_transaction_sequence;
1039 
1040 	/**
1041 	 * @j_commit_sequence:
1042 	 *
1043 	 * Sequence number of the most recently committed transaction
1044 	 * [j_state_lock, no lock for quick racy checks]
1045 	 */
1046 	tid_t			j_commit_sequence;
1047 
1048 	/**
1049 	 * @j_commit_request:
1050 	 *
1051 	 * Sequence number of the most recent transaction wanting commit
1052 	 * [j_state_lock, no lock for quick racy checks]
1053 	 */
1054 	tid_t			j_commit_request;
1055 
1056 	/**
1057 	 * @j_uuid:
1058 	 *
1059 	 * Journal uuid: identifies the object (filesystem, LVM volume etc)
1060 	 * backed by this journal.  This will eventually be replaced by an array
1061 	 * of uuids, allowing us to index multiple devices within a single
1062 	 * journal and to perform atomic updates across them.
1063 	 */
1064 	__u8			j_uuid[16];
1065 
1066 	/**
1067 	 * @j_task: Pointer to the current commit thread for this journal.
1068 	 */
1069 	struct task_struct	*j_task;
1070 
1071 	/**
1072 	 * @j_max_transaction_buffers:
1073 	 *
1074 	 * Maximum number of metadata buffers to allow in a single compound
1075 	 * commit transaction.
1076 	 */
1077 	int			j_max_transaction_buffers;
1078 
1079 	/**
1080 	 * @j_revoke_records_per_block:
1081 	 *
1082 	 * Number of revoke records that fit in one descriptor block.
1083 	 */
1084 	int			j_revoke_records_per_block;
1085 
1086 	/**
1087 	 * @j_commit_interval:
1088 	 *
1089 	 * What is the maximum transaction lifetime before we begin a commit?
1090 	 */
1091 	unsigned long		j_commit_interval;
1092 
1093 	/**
1094 	 * @j_commit_timer: The timer used to wakeup the commit thread.
1095 	 */
1096 	struct timer_list	j_commit_timer;
1097 
1098 	/**
1099 	 * @j_revoke_lock: Protect the revoke table.
1100 	 */
1101 	spinlock_t		j_revoke_lock;
1102 
1103 	/**
1104 	 * @j_revoke:
1105 	 *
1106 	 * The revoke table - maintains the list of revoked blocks in the
1107 	 * current transaction.
1108 	 */
1109 	struct jbd2_revoke_table_s *j_revoke;
1110 
1111 	/**
1112 	 * @j_revoke_table: Alternate revoke tables for j_revoke.
1113 	 */
1114 	struct jbd2_revoke_table_s *j_revoke_table[2];
1115 
1116 	/**
1117 	 * @j_wbuf: Array of bhs for jbd2_journal_commit_transaction.
1118 	 */
1119 	struct buffer_head	**j_wbuf;
1120 
1121 	/**
1122 	 * @j_fc_wbuf: Array of fast commit bhs for fast commit. Accessed only
1123 	 * during a fast commit. Currently only process can do fast commit, so
1124 	 * this field is not protected by any lock.
1125 	 */
1126 	struct buffer_head	**j_fc_wbuf;
1127 
1128 	/**
1129 	 * @j_wbufsize:
1130 	 *
1131 	 * Size of @j_wbuf array.
1132 	 */
1133 	int			j_wbufsize;
1134 
1135 	/**
1136 	 * @j_fc_wbufsize:
1137 	 *
1138 	 * Size of @j_fc_wbuf array.
1139 	 */
1140 	int			j_fc_wbufsize;
1141 
1142 	/**
1143 	 * @j_last_sync_writer:
1144 	 *
1145 	 * The pid of the last person to run a synchronous operation
1146 	 * through the journal.
1147 	 */
1148 	pid_t			j_last_sync_writer;
1149 
1150 	/**
1151 	 * @j_average_commit_time:
1152 	 *
1153 	 * The average amount of time in nanoseconds it takes to commit a
1154 	 * transaction to disk. [j_state_lock]
1155 	 */
1156 	u64			j_average_commit_time;
1157 
1158 	/**
1159 	 * @j_min_batch_time:
1160 	 *
1161 	 * Minimum time that we should wait for additional filesystem operations
1162 	 * to get batched into a synchronous handle in microseconds.
1163 	 */
1164 	u32			j_min_batch_time;
1165 
1166 	/**
1167 	 * @j_max_batch_time:
1168 	 *
1169 	 * Maximum time that we should wait for additional filesystem operations
1170 	 * to get batched into a synchronous handle in microseconds.
1171 	 */
1172 	u32			j_max_batch_time;
1173 
1174 	/**
1175 	 * @j_commit_callback:
1176 	 *
1177 	 * This function is called when a transaction is closed.
1178 	 */
1179 	void			(*j_commit_callback)(journal_t *,
1180 						     transaction_t *);
1181 
1182 	/**
1183 	 * @j_submit_inode_data_buffers:
1184 	 *
1185 	 * This function is called for all inodes associated with the
1186 	 * committing transaction marked with JI_WRITE_DATA flag
1187 	 * before we start to write out the transaction to the journal.
1188 	 */
1189 	int			(*j_submit_inode_data_buffers)
1190 					(struct jbd2_inode *);
1191 
1192 	/**
1193 	 * @j_finish_inode_data_buffers:
1194 	 *
1195 	 * This function is called for all inodes associated with the
1196 	 * committing transaction marked with JI_WAIT_DATA flag
1197 	 * after we have written the transaction to the journal
1198 	 * but before we write out the commit block.
1199 	 */
1200 	int			(*j_finish_inode_data_buffers)
1201 					(struct jbd2_inode *);
1202 
1203 	/*
1204 	 * Journal statistics
1205 	 */
1206 
1207 	/**
1208 	 * @j_history_lock: Protect the transactions statistics history.
1209 	 */
1210 	spinlock_t		j_history_lock;
1211 
1212 	/**
1213 	 * @j_proc_entry: procfs entry for the jbd statistics directory.
1214 	 */
1215 	struct proc_dir_entry	*j_proc_entry;
1216 
1217 	/**
1218 	 * @j_stats: Overall statistics.
1219 	 */
1220 	struct transaction_stats_s j_stats;
1221 
1222 	/**
1223 	 * @j_failed_commit: Failed journal commit ID.
1224 	 */
1225 	unsigned int		j_failed_commit;
1226 
1227 	/**
1228 	 * @j_private:
1229 	 *
1230 	 * An opaque pointer to fs-private information.  ext3 puts its
1231 	 * superblock pointer here.
1232 	 */
1233 	void *j_private;
1234 
1235 	/**
1236 	 * @j_chksum_driver:
1237 	 *
1238 	 * Reference to checksum algorithm driver via cryptoapi.
1239 	 */
1240 	struct crypto_shash *j_chksum_driver;
1241 
1242 	/**
1243 	 * @j_csum_seed:
1244 	 *
1245 	 * Precomputed journal UUID checksum for seeding other checksums.
1246 	 */
1247 	__u32 j_csum_seed;
1248 
1249 #ifdef CONFIG_DEBUG_LOCK_ALLOC
1250 	/**
1251 	 * @j_trans_commit_map:
1252 	 *
1253 	 * Lockdep entity to track transaction commit dependencies. Handles
1254 	 * hold this "lock" for read, when we wait for commit, we acquire the
1255 	 * "lock" for writing. This matches the properties of jbd2 journalling
1256 	 * where the running transaction has to wait for all handles to be
1257 	 * dropped to commit that transaction and also acquiring a handle may
1258 	 * require transaction commit to finish.
1259 	 */
1260 	struct lockdep_map	j_trans_commit_map;
1261 #endif
1262 
1263 	/**
1264 	 * @j_fc_cleanup_callback:
1265 	 *
1266 	 * Clean-up after fast commit or full commit. JBD2 calls this function
1267 	 * after every commit operation.
1268 	 */
1269 	void (*j_fc_cleanup_callback)(struct journal_s *journal, int full, tid_t tid);
1270 
1271 	/**
1272 	 * @j_fc_replay_callback:
1273 	 *
1274 	 * File-system specific function that performs replay of a fast
1275 	 * commit. JBD2 calls this function for each fast commit block found in
1276 	 * the journal. This function should return JBD2_FC_REPLAY_CONTINUE
1277 	 * to indicate that the block was processed correctly and more fast
1278 	 * commit replay should continue. Return value of JBD2_FC_REPLAY_STOP
1279 	 * indicates the end of replay (no more blocks remaining). A negative
1280 	 * return value indicates error.
1281 	 */
1282 	int (*j_fc_replay_callback)(struct journal_s *journal,
1283 				    struct buffer_head *bh,
1284 				    enum passtype pass, int off,
1285 				    tid_t expected_commit_id);
1286 
1287 	/**
1288 	 * @j_bmap:
1289 	 *
1290 	 * Bmap function that should be used instead of the generic
1291 	 * VFS bmap function.
1292 	 */
1293 	int (*j_bmap)(struct journal_s *journal, sector_t *block);
1294 };
1295 
1296 #define jbd2_might_wait_for_commit(j) \
1297 	do { \
1298 		rwsem_acquire(&j->j_trans_commit_map, 0, 0, _THIS_IP_); \
1299 		rwsem_release(&j->j_trans_commit_map, _THIS_IP_); \
1300 	} while (0)
1301 
1302 /*
1303  * We can support any known requested features iff the
1304  * superblock is not in version 1.  Otherwise we fail to support any
1305  * extended sb features.
1306  */
jbd2_format_support_feature(journal_t * j)1307 static inline bool jbd2_format_support_feature(journal_t *j)
1308 {
1309 	return j->j_superblock->s_header.h_blocktype !=
1310 					cpu_to_be32(JBD2_SUPERBLOCK_V1);
1311 }
1312 
1313 /* journal feature predicate functions */
1314 #define JBD2_FEATURE_COMPAT_FUNCS(name, flagname) \
1315 static inline bool jbd2_has_feature_##name(journal_t *j) \
1316 { \
1317 	return (jbd2_format_support_feature(j) && \
1318 		((j)->j_superblock->s_feature_compat & \
1319 		 cpu_to_be32(JBD2_FEATURE_COMPAT_##flagname)) != 0); \
1320 } \
1321 static inline void jbd2_set_feature_##name(journal_t *j) \
1322 { \
1323 	(j)->j_superblock->s_feature_compat |= \
1324 		cpu_to_be32(JBD2_FEATURE_COMPAT_##flagname); \
1325 } \
1326 static inline void jbd2_clear_feature_##name(journal_t *j) \
1327 { \
1328 	(j)->j_superblock->s_feature_compat &= \
1329 		~cpu_to_be32(JBD2_FEATURE_COMPAT_##flagname); \
1330 }
1331 
1332 #define JBD2_FEATURE_RO_COMPAT_FUNCS(name, flagname) \
1333 static inline bool jbd2_has_feature_##name(journal_t *j) \
1334 { \
1335 	return (jbd2_format_support_feature(j) && \
1336 		((j)->j_superblock->s_feature_ro_compat & \
1337 		 cpu_to_be32(JBD2_FEATURE_RO_COMPAT_##flagname)) != 0); \
1338 } \
1339 static inline void jbd2_set_feature_##name(journal_t *j) \
1340 { \
1341 	(j)->j_superblock->s_feature_ro_compat |= \
1342 		cpu_to_be32(JBD2_FEATURE_RO_COMPAT_##flagname); \
1343 } \
1344 static inline void jbd2_clear_feature_##name(journal_t *j) \
1345 { \
1346 	(j)->j_superblock->s_feature_ro_compat &= \
1347 		~cpu_to_be32(JBD2_FEATURE_RO_COMPAT_##flagname); \
1348 }
1349 
1350 #define JBD2_FEATURE_INCOMPAT_FUNCS(name, flagname) \
1351 static inline bool jbd2_has_feature_##name(journal_t *j) \
1352 { \
1353 	return (jbd2_format_support_feature(j) && \
1354 		((j)->j_superblock->s_feature_incompat & \
1355 		 cpu_to_be32(JBD2_FEATURE_INCOMPAT_##flagname)) != 0); \
1356 } \
1357 static inline void jbd2_set_feature_##name(journal_t *j) \
1358 { \
1359 	(j)->j_superblock->s_feature_incompat |= \
1360 		cpu_to_be32(JBD2_FEATURE_INCOMPAT_##flagname); \
1361 } \
1362 static inline void jbd2_clear_feature_##name(journal_t *j) \
1363 { \
1364 	(j)->j_superblock->s_feature_incompat &= \
1365 		~cpu_to_be32(JBD2_FEATURE_INCOMPAT_##flagname); \
1366 }
1367 
1368 JBD2_FEATURE_COMPAT_FUNCS(checksum,		CHECKSUM)
1369 
1370 JBD2_FEATURE_INCOMPAT_FUNCS(revoke,		REVOKE)
1371 JBD2_FEATURE_INCOMPAT_FUNCS(64bit,		64BIT)
1372 JBD2_FEATURE_INCOMPAT_FUNCS(async_commit,	ASYNC_COMMIT)
1373 JBD2_FEATURE_INCOMPAT_FUNCS(csum2,		CSUM_V2)
1374 JBD2_FEATURE_INCOMPAT_FUNCS(csum3,		CSUM_V3)
1375 JBD2_FEATURE_INCOMPAT_FUNCS(fast_commit,	FAST_COMMIT)
1376 
1377 /* Journal high priority write IO operation flags */
1378 #define JBD2_JOURNAL_REQ_FLAGS		(REQ_META | REQ_SYNC | REQ_IDLE)
1379 
1380 /*
1381  * Journal flag definitions
1382  */
1383 #define JBD2_UNMOUNT	0x001	/* Journal thread is being destroyed */
1384 #define JBD2_ABORT	0x002	/* Journaling has been aborted for errors. */
1385 #define JBD2_ACK_ERR	0x004	/* The errno in the sb has been acked */
1386 #define JBD2_FLUSHED	0x008	/* The journal superblock has been flushed */
1387 #define JBD2_LOADED	0x010	/* The journal superblock has been loaded */
1388 #define JBD2_BARRIER	0x020	/* Use IDE barriers */
1389 #define JBD2_ABORT_ON_SYNCDATA_ERR	0x040	/* Abort the journal on file
1390 						 * data write error in ordered
1391 						 * mode */
1392 #define JBD2_CYCLE_RECORD		0x080	/* Journal cycled record log on
1393 						 * clean and empty filesystem
1394 						 * logging area */
1395 #define JBD2_FAST_COMMIT_ONGOING	0x100	/* Fast commit is ongoing */
1396 #define JBD2_FULL_COMMIT_ONGOING	0x200	/* Full commit is ongoing */
1397 #define JBD2_JOURNAL_FLUSH_DISCARD	0x0001
1398 #define JBD2_JOURNAL_FLUSH_ZEROOUT	0x0002
1399 #define JBD2_JOURNAL_FLUSH_VALID	(JBD2_JOURNAL_FLUSH_DISCARD | \
1400 					JBD2_JOURNAL_FLUSH_ZEROOUT)
1401 
1402 /*
1403  * Journal atomic flag definitions
1404  */
1405 #define JBD2_CHECKPOINT_IO_ERROR	0x001	/* Detect io error while writing
1406 						 * buffer back to disk */
1407 
1408 /*
1409  * Function declarations for the journaling transaction and buffer
1410  * management
1411  */
1412 
1413 /* Filing buffers */
1414 extern void jbd2_journal_unfile_buffer(journal_t *, struct journal_head *);
1415 extern bool __jbd2_journal_refile_buffer(struct journal_head *);
1416 extern void jbd2_journal_refile_buffer(journal_t *, struct journal_head *);
1417 extern void __jbd2_journal_file_buffer(struct journal_head *, transaction_t *, int);
1418 extern void jbd2_journal_file_buffer(struct journal_head *, transaction_t *, int);
jbd2_file_log_bh(struct list_head * head,struct buffer_head * bh)1419 static inline void jbd2_file_log_bh(struct list_head *head, struct buffer_head *bh)
1420 {
1421 	list_add_tail(&bh->b_assoc_buffers, head);
1422 }
jbd2_unfile_log_bh(struct buffer_head * bh)1423 static inline void jbd2_unfile_log_bh(struct buffer_head *bh)
1424 {
1425 	list_del_init(&bh->b_assoc_buffers);
1426 }
1427 
1428 /* Log buffer allocation */
1429 struct buffer_head *jbd2_journal_get_descriptor_buffer(transaction_t *, int);
1430 void jbd2_descriptor_block_csum_set(journal_t *, struct buffer_head *);
1431 int jbd2_journal_next_log_block(journal_t *, unsigned long long *);
1432 int jbd2_journal_get_log_tail(journal_t *journal, tid_t *tid,
1433 			      unsigned long *block);
1434 int __jbd2_update_log_tail(journal_t *journal, tid_t tid, unsigned long block);
1435 void jbd2_update_log_tail(journal_t *journal, tid_t tid, unsigned long block);
1436 
1437 /* Commit management */
1438 extern void jbd2_journal_commit_transaction(journal_t *);
1439 
1440 /* Checkpoint list management */
1441 void __jbd2_journal_clean_checkpoint_list(journal_t *journal, bool destroy);
1442 unsigned long jbd2_journal_shrink_checkpoint_list(journal_t *journal, unsigned long *nr_to_scan);
1443 int __jbd2_journal_remove_checkpoint(struct journal_head *);
1444 int jbd2_journal_try_remove_checkpoint(struct journal_head *jh);
1445 void jbd2_journal_destroy_checkpoint(journal_t *journal);
1446 void __jbd2_journal_insert_checkpoint(struct journal_head *, transaction_t *);
1447 
1448 
1449 /*
1450  * Triggers
1451  */
1452 
1453 struct jbd2_buffer_trigger_type {
1454 	/*
1455 	 * Fired a the moment data to write to the journal are known to be
1456 	 * stable - so either at the moment b_frozen_data is created or just
1457 	 * before a buffer is written to the journal.  mapped_data is a mapped
1458 	 * buffer that is the frozen data for commit.
1459 	 */
1460 	void (*t_frozen)(struct jbd2_buffer_trigger_type *type,
1461 			 struct buffer_head *bh, void *mapped_data,
1462 			 size_t size);
1463 
1464 	/*
1465 	 * Fired during journal abort for dirty buffers that will not be
1466 	 * committed.
1467 	 */
1468 	void (*t_abort)(struct jbd2_buffer_trigger_type *type,
1469 			struct buffer_head *bh);
1470 };
1471 
1472 extern void jbd2_buffer_frozen_trigger(struct journal_head *jh,
1473 				       void *mapped_data,
1474 				       struct jbd2_buffer_trigger_type *triggers);
1475 extern void jbd2_buffer_abort_trigger(struct journal_head *jh,
1476 				      struct jbd2_buffer_trigger_type *triggers);
1477 
1478 /* Buffer IO */
1479 extern int jbd2_journal_write_metadata_buffer(transaction_t *transaction,
1480 					      struct journal_head *jh_in,
1481 					      struct buffer_head **bh_out,
1482 					      sector_t blocknr);
1483 
1484 /* Transaction cache support */
1485 extern void jbd2_journal_destroy_transaction_cache(void);
1486 extern int __init jbd2_journal_init_transaction_cache(void);
1487 extern void jbd2_journal_free_transaction(transaction_t *);
1488 
1489 /*
1490  * Journal locking.
1491  *
1492  * We need to lock the journal during transaction state changes so that nobody
1493  * ever tries to take a handle on the running transaction while we are in the
1494  * middle of moving it to the commit phase.  j_state_lock does this.
1495  *
1496  * Note that the locking is completely interrupt unsafe.  We never touch
1497  * journal structures from interrupts.
1498  */
1499 
journal_current_handle(void)1500 static inline handle_t *journal_current_handle(void)
1501 {
1502 	return current->journal_info;
1503 }
1504 
1505 /* The journaling code user interface:
1506  *
1507  * Create and destroy handles
1508  * Register buffer modifications against the current transaction.
1509  */
1510 
1511 extern handle_t *jbd2_journal_start(journal_t *, int nblocks);
1512 extern handle_t *jbd2__journal_start(journal_t *, int blocks, int rsv_blocks,
1513 				     int revoke_records, gfp_t gfp_mask,
1514 				     unsigned int type, unsigned int line_no);
1515 extern int	 jbd2_journal_restart(handle_t *, int nblocks);
1516 extern int	 jbd2__journal_restart(handle_t *, int nblocks,
1517 				       int revoke_records, gfp_t gfp_mask);
1518 extern int	 jbd2_journal_start_reserved(handle_t *handle,
1519 				unsigned int type, unsigned int line_no);
1520 extern void	 jbd2_journal_free_reserved(handle_t *handle);
1521 extern int	 jbd2_journal_extend(handle_t *handle, int nblocks,
1522 				     int revoke_records);
1523 extern int	 jbd2_journal_get_write_access(handle_t *, struct buffer_head *);
1524 extern int	 jbd2_journal_get_create_access (handle_t *, struct buffer_head *);
1525 extern int	 jbd2_journal_get_undo_access(handle_t *, struct buffer_head *);
1526 void		 jbd2_journal_set_triggers(struct buffer_head *,
1527 					   struct jbd2_buffer_trigger_type *type);
1528 extern int	 jbd2_journal_dirty_metadata (handle_t *, struct buffer_head *);
1529 extern int	 jbd2_journal_forget (handle_t *, struct buffer_head *);
1530 int jbd2_journal_invalidate_folio(journal_t *, struct folio *,
1531 					size_t offset, size_t length);
1532 bool jbd2_journal_try_to_free_buffers(journal_t *journal, struct folio *folio);
1533 extern int	 jbd2_journal_stop(handle_t *);
1534 extern int	 jbd2_journal_flush(journal_t *journal, unsigned int flags);
1535 extern void	 jbd2_journal_lock_updates (journal_t *);
1536 extern void	 jbd2_journal_unlock_updates (journal_t *);
1537 
1538 void jbd2_journal_wait_updates(journal_t *);
1539 
1540 extern journal_t * jbd2_journal_init_dev(struct block_device *bdev,
1541 				struct block_device *fs_dev,
1542 				unsigned long long start, int len, int bsize);
1543 extern journal_t * jbd2_journal_init_inode (struct inode *);
1544 extern int	   jbd2_journal_update_format (journal_t *);
1545 extern int	   jbd2_journal_check_used_features
1546 		   (journal_t *, unsigned long, unsigned long, unsigned long);
1547 extern int	   jbd2_journal_check_available_features
1548 		   (journal_t *, unsigned long, unsigned long, unsigned long);
1549 extern int	   jbd2_journal_set_features
1550 		   (journal_t *, unsigned long, unsigned long, unsigned long);
1551 extern void	   jbd2_journal_clear_features
1552 		   (journal_t *, unsigned long, unsigned long, unsigned long);
1553 extern int	   jbd2_journal_load       (journal_t *journal);
1554 extern int	   jbd2_journal_destroy    (journal_t *);
1555 extern int	   jbd2_journal_recover    (journal_t *journal);
1556 extern int	   jbd2_journal_wipe       (journal_t *, int);
1557 extern int	   jbd2_journal_skip_recovery	(journal_t *);
1558 extern void	   jbd2_journal_update_sb_errno(journal_t *);
1559 extern int	   jbd2_journal_update_sb_log_tail	(journal_t *, tid_t,
1560 				unsigned long, blk_opf_t);
1561 extern void	   jbd2_journal_abort      (journal_t *, int);
1562 extern int	   jbd2_journal_errno      (journal_t *);
1563 extern void	   jbd2_journal_ack_err    (journal_t *);
1564 extern int	   jbd2_journal_clear_err  (journal_t *);
1565 extern int	   jbd2_journal_bmap(journal_t *, unsigned long, unsigned long long *);
1566 extern int	   jbd2_journal_force_commit(journal_t *);
1567 extern int	   jbd2_journal_force_commit_nested(journal_t *);
1568 extern int	   jbd2_journal_inode_ranged_write(handle_t *handle,
1569 			struct jbd2_inode *inode, loff_t start_byte,
1570 			loff_t length);
1571 extern int	   jbd2_journal_inode_ranged_wait(handle_t *handle,
1572 			struct jbd2_inode *inode, loff_t start_byte,
1573 			loff_t length);
1574 extern int	   jbd2_journal_finish_inode_data_buffers(
1575 			struct jbd2_inode *jinode);
1576 extern int	   jbd2_journal_begin_ordered_truncate(journal_t *journal,
1577 				struct jbd2_inode *inode, loff_t new_size);
1578 extern void	   jbd2_journal_init_jbd_inode(struct jbd2_inode *jinode, struct inode *inode);
1579 extern void	   jbd2_journal_release_jbd_inode(journal_t *journal, struct jbd2_inode *jinode);
1580 
1581 /*
1582  * journal_head management
1583  */
1584 struct journal_head *jbd2_journal_add_journal_head(struct buffer_head *bh);
1585 struct journal_head *jbd2_journal_grab_journal_head(struct buffer_head *bh);
1586 void jbd2_journal_put_journal_head(struct journal_head *jh);
1587 
1588 /*
1589  * handle management
1590  */
1591 extern struct kmem_cache *jbd2_handle_cache;
1592 
jbd2_alloc_handle(gfp_t gfp_flags)1593 static inline handle_t *jbd2_alloc_handle(gfp_t gfp_flags)
1594 {
1595 	return kmem_cache_zalloc(jbd2_handle_cache, gfp_flags);
1596 }
1597 
jbd2_free_handle(handle_t * handle)1598 static inline void jbd2_free_handle(handle_t *handle)
1599 {
1600 	kmem_cache_free(jbd2_handle_cache, handle);
1601 }
1602 
1603 /*
1604  * jbd2_inode management (optional, for those file systems that want to use
1605  * dynamically allocated jbd2_inode structures)
1606  */
1607 extern struct kmem_cache *jbd2_inode_cache;
1608 
jbd2_alloc_inode(gfp_t gfp_flags)1609 static inline struct jbd2_inode *jbd2_alloc_inode(gfp_t gfp_flags)
1610 {
1611 	return kmem_cache_alloc(jbd2_inode_cache, gfp_flags);
1612 }
1613 
jbd2_free_inode(struct jbd2_inode * jinode)1614 static inline void jbd2_free_inode(struct jbd2_inode *jinode)
1615 {
1616 	kmem_cache_free(jbd2_inode_cache, jinode);
1617 }
1618 
1619 /* Primary revoke support */
1620 #define JOURNAL_REVOKE_DEFAULT_HASH 256
1621 extern int	   jbd2_journal_init_revoke(journal_t *, int);
1622 extern void	   jbd2_journal_destroy_revoke_record_cache(void);
1623 extern void	   jbd2_journal_destroy_revoke_table_cache(void);
1624 extern int __init jbd2_journal_init_revoke_record_cache(void);
1625 extern int __init jbd2_journal_init_revoke_table_cache(void);
1626 
1627 extern void	   jbd2_journal_destroy_revoke(journal_t *);
1628 extern int	   jbd2_journal_revoke (handle_t *, unsigned long long, struct buffer_head *);
1629 extern int	   jbd2_journal_cancel_revoke(handle_t *, struct journal_head *);
1630 extern void	   jbd2_journal_write_revoke_records(transaction_t *transaction,
1631 						     struct list_head *log_bufs);
1632 
1633 /* Recovery revoke support */
1634 extern int	jbd2_journal_set_revoke(journal_t *, unsigned long long, tid_t);
1635 extern int	jbd2_journal_test_revoke(journal_t *, unsigned long long, tid_t);
1636 extern void	jbd2_journal_clear_revoke(journal_t *);
1637 extern void	jbd2_journal_switch_revoke_table(journal_t *journal);
1638 extern void	jbd2_clear_buffer_revoked_flags(journal_t *journal);
1639 
1640 /*
1641  * The log thread user interface:
1642  *
1643  * Request space in the current transaction, and force transaction commit
1644  * transitions on demand.
1645  */
1646 
1647 int jbd2_log_start_commit(journal_t *journal, tid_t tid);
1648 int jbd2_journal_start_commit(journal_t *journal, tid_t *tid);
1649 int jbd2_log_wait_commit(journal_t *journal, tid_t tid);
1650 int jbd2_transaction_committed(journal_t *journal, tid_t tid);
1651 int jbd2_complete_transaction(journal_t *journal, tid_t tid);
1652 int jbd2_log_do_checkpoint(journal_t *journal);
1653 int jbd2_trans_will_send_data_barrier(journal_t *journal, tid_t tid);
1654 
1655 void __jbd2_log_wait_for_space(journal_t *journal);
1656 extern void __jbd2_journal_drop_transaction(journal_t *, transaction_t *);
1657 extern int jbd2_cleanup_journal_tail(journal_t *);
1658 
1659 /* Fast commit related APIs */
1660 int jbd2_fc_begin_commit(journal_t *journal, tid_t tid);
1661 int jbd2_fc_end_commit(journal_t *journal);
1662 int jbd2_fc_end_commit_fallback(journal_t *journal);
1663 int jbd2_fc_get_buf(journal_t *journal, struct buffer_head **bh_out);
1664 int jbd2_submit_inode_data(journal_t *journal, struct jbd2_inode *jinode);
1665 int jbd2_wait_inode_data(journal_t *journal, struct jbd2_inode *jinode);
1666 int jbd2_fc_wait_bufs(journal_t *journal, int num_blks);
1667 int jbd2_fc_release_bufs(journal_t *journal);
1668 
jbd2_journal_get_max_txn_bufs(journal_t * journal)1669 static inline int jbd2_journal_get_max_txn_bufs(journal_t *journal)
1670 {
1671 	return (journal->j_total_len - journal->j_fc_wbufsize) / 4;
1672 }
1673 
1674 /*
1675  * is_journal_abort
1676  *
1677  * Simple test wrapper function to test the JBD2_ABORT state flag.  This
1678  * bit, when set, indicates that we have had a fatal error somewhere,
1679  * either inside the journaling layer or indicated to us by the client
1680  * (eg. ext3), and that we and should not commit any further
1681  * transactions.
1682  */
1683 
is_journal_aborted(journal_t * journal)1684 static inline int is_journal_aborted(journal_t *journal)
1685 {
1686 	return journal->j_flags & JBD2_ABORT;
1687 }
1688 
is_handle_aborted(handle_t * handle)1689 static inline int is_handle_aborted(handle_t *handle)
1690 {
1691 	if (handle->h_aborted || !handle->h_transaction)
1692 		return 1;
1693 	return is_journal_aborted(handle->h_transaction->t_journal);
1694 }
1695 
jbd2_journal_abort_handle(handle_t * handle)1696 static inline void jbd2_journal_abort_handle(handle_t *handle)
1697 {
1698 	handle->h_aborted = 1;
1699 }
1700 
1701 #endif /* __KERNEL__   */
1702 
1703 /* Comparison functions for transaction IDs: perform comparisons using
1704  * modulo arithmetic so that they work over sequence number wraps. */
1705 
tid_gt(tid_t x,tid_t y)1706 static inline int tid_gt(tid_t x, tid_t y)
1707 {
1708 	int difference = (x - y);
1709 	return (difference > 0);
1710 }
1711 
tid_geq(tid_t x,tid_t y)1712 static inline int tid_geq(tid_t x, tid_t y)
1713 {
1714 	int difference = (x - y);
1715 	return (difference >= 0);
1716 }
1717 
1718 extern int jbd2_journal_blocks_per_page(struct inode *inode);
1719 extern size_t journal_tag_bytes(journal_t *journal);
1720 
jbd2_journal_has_csum_v2or3_feature(journal_t * j)1721 static inline bool jbd2_journal_has_csum_v2or3_feature(journal_t *j)
1722 {
1723 	return jbd2_has_feature_csum2(j) || jbd2_has_feature_csum3(j);
1724 }
1725 
jbd2_journal_has_csum_v2or3(journal_t * journal)1726 static inline int jbd2_journal_has_csum_v2or3(journal_t *journal)
1727 {
1728 	WARN_ON_ONCE(jbd2_journal_has_csum_v2or3_feature(journal) &&
1729 		     journal->j_chksum_driver == NULL);
1730 
1731 	return journal->j_chksum_driver != NULL;
1732 }
1733 
jbd2_journal_get_num_fc_blks(journal_superblock_t * jsb)1734 static inline int jbd2_journal_get_num_fc_blks(journal_superblock_t *jsb)
1735 {
1736 	int num_fc_blocks = be32_to_cpu(jsb->s_num_fc_blks);
1737 
1738 	return num_fc_blocks ? num_fc_blocks : JBD2_DEFAULT_FAST_COMMIT_BLOCKS;
1739 }
1740 
1741 /*
1742  * Return number of free blocks in the log. Must be called under j_state_lock.
1743  */
jbd2_log_space_left(journal_t * journal)1744 static inline unsigned long jbd2_log_space_left(journal_t *journal)
1745 {
1746 	/* Allow for rounding errors */
1747 	long free = journal->j_free - 32;
1748 
1749 	if (journal->j_committing_transaction) {
1750 		free -= atomic_read(&journal->
1751                         j_committing_transaction->t_outstanding_credits);
1752 	}
1753 	return max_t(long, free, 0);
1754 }
1755 
1756 /*
1757  * Definitions which augment the buffer_head layer
1758  */
1759 
1760 /* journaling buffer types */
1761 #define BJ_None		0	/* Not journaled */
1762 #define BJ_Metadata	1	/* Normal journaled metadata */
1763 #define BJ_Forget	2	/* Buffer superseded by this transaction */
1764 #define BJ_Shadow	3	/* Buffer contents being shadowed to the log */
1765 #define BJ_Reserved	4	/* Buffer is reserved for access by journal */
1766 #define BJ_Types	5
1767 
1768 /* JBD uses a CRC32 checksum */
1769 #define JBD_MAX_CHECKSUM_SIZE 4
1770 
jbd2_chksum(journal_t * journal,u32 crc,const void * address,unsigned int length)1771 static inline u32 jbd2_chksum(journal_t *journal, u32 crc,
1772 			      const void *address, unsigned int length)
1773 {
1774 	struct {
1775 		struct shash_desc shash;
1776 		char ctx[JBD_MAX_CHECKSUM_SIZE];
1777 	} desc;
1778 	int err;
1779 
1780 	BUG_ON(crypto_shash_descsize(journal->j_chksum_driver) >
1781 		JBD_MAX_CHECKSUM_SIZE);
1782 
1783 	desc.shash.tfm = journal->j_chksum_driver;
1784 	*(u32 *)desc.ctx = crc;
1785 
1786 	err = crypto_shash_update(&desc.shash, address, length);
1787 	BUG_ON(err);
1788 
1789 	return *(u32 *)desc.ctx;
1790 }
1791 
1792 /* Return most recent uncommitted transaction */
jbd2_get_latest_transaction(journal_t * journal)1793 static inline tid_t  jbd2_get_latest_transaction(journal_t *journal)
1794 {
1795 	tid_t tid;
1796 
1797 	read_lock(&journal->j_state_lock);
1798 	tid = journal->j_commit_request;
1799 	if (journal->j_running_transaction)
1800 		tid = journal->j_running_transaction->t_tid;
1801 	read_unlock(&journal->j_state_lock);
1802 	return tid;
1803 }
1804 
jbd2_handle_buffer_credits(handle_t * handle)1805 static inline int jbd2_handle_buffer_credits(handle_t *handle)
1806 {
1807 	journal_t *journal;
1808 
1809 	if (!handle->h_reserved)
1810 		journal = handle->h_transaction->t_journal;
1811 	else
1812 		journal = handle->h_journal;
1813 
1814 	return handle->h_total_credits -
1815 		DIV_ROUND_UP(handle->h_revoke_credits_requested,
1816 			     journal->j_revoke_records_per_block);
1817 }
1818 
1819 #ifdef __KERNEL__
1820 
1821 #define buffer_trace_init(bh)	do {} while (0)
1822 #define print_buffer_fields(bh)	do {} while (0)
1823 #define print_buffer_trace(bh)	do {} while (0)
1824 #define BUFFER_TRACE(bh, info)	do {} while (0)
1825 #define BUFFER_TRACE2(bh, bh2, info)	do {} while (0)
1826 #define JBUFFER_TRACE(jh, info)	do {} while (0)
1827 
1828 #endif	/* __KERNEL__ */
1829 
1830 #define EFSBADCRC	EBADMSG		/* Bad CRC detected */
1831 #define EFSCORRUPTED	EUCLEAN		/* Filesystem is corrupted */
1832 
1833 #endif	/* _LINUX_JBD2_H */
1834