Current File : //proc/thread-self/root/usr/src/linux-headers-6.8.0-59/include/linux/jbd2.h
/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
 * linux/include/linux/jbd2.h
 *
 * Written by Stephen C. Tweedie <sct@redhat.com>
 *
 * Copyright 1998-2000 Red Hat, Inc --- All Rights Reserved
 *
 * Definitions for transaction data structures for the buffer cache
 * filesystem journaling support.
 */

#ifndef _LINUX_JBD2_H
#define _LINUX_JBD2_H

/* Allow this file to be included directly into e2fsprogs */
#ifndef __KERNEL__
#include "jfs_compat.h"
#define JBD2_DEBUG
#else

#include <linux/types.h>
#include <linux/buffer_head.h>
#include <linux/journal-head.h>
#include <linux/stddef.h>
#include <linux/mutex.h>
#include <linux/timer.h>
#include <linux/slab.h>
#include <linux/bit_spinlock.h>
#include <linux/blkdev.h>
#include <crypto/hash.h>
#endif

#define journal_oom_retry 1

/*
 * Define JBD2_PARANIOD_IOFAIL to cause a kernel BUG() if ext4 finds
 * certain classes of error which can occur due to failed IOs.  Under
 * normal use we want ext4 to continue after such errors, because
 * hardware _can_ fail, but for debugging purposes when running tests on
 * known-good hardware we may want to trap these errors.
 */
#undef JBD2_PARANOID_IOFAIL

/*
 * The default maximum commit age, in seconds.
 */
#define JBD2_DEFAULT_MAX_COMMIT_AGE 5

#ifdef CONFIG_JBD2_DEBUG
/*
 * Define JBD2_EXPENSIVE_CHECKING to enable more expensive internal
 * consistency checks.  By default we don't do this unless
 * CONFIG_JBD2_DEBUG is on.
 */
#define JBD2_EXPENSIVE_CHECKING
void __jbd2_debug(int level, const char *file, const char *func,
		  unsigned int line, const char *fmt, ...);

#define jbd2_debug(n, fmt, a...) \
	__jbd2_debug((n), __FILE__, __func__, __LINE__, (fmt), ##a)
#else
#define jbd2_debug(n, fmt, a...)  no_printk(fmt, ##a)
#endif

extern void *jbd2_alloc(size_t size, gfp_t flags);
extern void jbd2_free(void *ptr, size_t size);

#define JBD2_MIN_JOURNAL_BLOCKS 1024
#define JBD2_DEFAULT_FAST_COMMIT_BLOCKS 256

#ifdef __KERNEL__

/**
 * typedef handle_t - The handle_t type represents a single atomic update being performed by some process.
 *
 * All filesystem modifications made by the process go
 * through this handle.  Recursive operations (such as quota operations)
 * are gathered into a single update.
 *
 * The buffer credits field is used to account for journaled buffers
 * being modified by the running process.  To ensure that there is
 * enough log space for all outstanding operations, we need to limit the
 * number of outstanding buffers possible at any time.  When the
 * operation completes, any buffer credits not used are credited back to
 * the transaction, so that at all times we know how many buffers the
 * outstanding updates on a transaction might possibly touch.
 *
 * This is an opaque datatype.
 **/
typedef struct jbd2_journal_handle handle_t;	/* Atomic operation type */


/**
 * typedef journal_t - The journal_t maintains all of the journaling state information for a single filesystem.
 *
 * journal_t is linked to from the fs superblock structure.
 *
 * We use the journal_t to keep track of all outstanding transaction
 * activity on the filesystem, and to manage the state of the log
 * writing process.
 *
 * This is an opaque datatype.
 **/
typedef struct journal_s	journal_t;	/* Journal control structure */
#endif

/*
 * Internal structures used by the logging mechanism:
 */

#define JBD2_MAGIC_NUMBER 0xc03b3998U /* The first 4 bytes of /dev/random! */

/*
 * On-disk structures
 */

/*
 * Descriptor block types:
 */

#define JBD2_DESCRIPTOR_BLOCK	1
#define JBD2_COMMIT_BLOCK	2
#define JBD2_SUPERBLOCK_V1	3
#define JBD2_SUPERBLOCK_V2	4
#define JBD2_REVOKE_BLOCK	5

/*
 * Standard header for all descriptor blocks:
 */
typedef struct journal_header_s
{
	__be32		h_magic;
	__be32		h_blocktype;
	__be32		h_sequence;
} journal_header_t;

/*
 * Checksum types.
 */
#define JBD2_CRC32_CHKSUM   1
#define JBD2_MD5_CHKSUM     2
#define JBD2_SHA1_CHKSUM    3
#define JBD2_CRC32C_CHKSUM  4

#define JBD2_CRC32_CHKSUM_SIZE 4

#define JBD2_CHECKSUM_BYTES (32 / sizeof(u32))
/*
 * Commit block header for storing transactional checksums:
 *
 * NOTE: If FEATURE_COMPAT_CHECKSUM (checksum v1) is set, the h_chksum*
 * fields are used to store a checksum of the descriptor and data blocks.
 *
 * If FEATURE_INCOMPAT_CSUM_V2 (checksum v2) is set, then the h_chksum
 * field is used to store crc32c(uuid+commit_block).  Each journal metadata
 * block gets its own checksum, and data block checksums are stored in
 * journal_block_tag (in the descriptor).  The other h_chksum* fields are
 * not used.
 *
 * If FEATURE_INCOMPAT_CSUM_V3 is set, the descriptor block uses
 * journal_block_tag3_t to store a full 32-bit checksum.  Everything else
 * is the same as v2.
 *
 * Checksum v1, v2, and v3 are mutually exclusive features.
 */
struct commit_header {
	__be32		h_magic;
	__be32          h_blocktype;
	__be32          h_sequence;
	unsigned char   h_chksum_type;
	unsigned char   h_chksum_size;
	unsigned char 	h_padding[2];
	__be32 		h_chksum[JBD2_CHECKSUM_BYTES];
	__be64		h_commit_sec;
	__be32		h_commit_nsec;
};

/*
 * The block tag: used to describe a single buffer in the journal.
 * t_blocknr_high is only used if INCOMPAT_64BIT is set, so this
 * raw struct shouldn't be used for pointer math or sizeof() - use
 * journal_tag_bytes(journal) instead to compute this.
 */
typedef struct journal_block_tag3_s
{
	__be32		t_blocknr;	/* The on-disk block number */
	__be32		t_flags;	/* See below */
	__be32		t_blocknr_high; /* most-significant high 32bits. */
	__be32		t_checksum;	/* crc32c(uuid+seq+block) */
} journal_block_tag3_t;

typedef struct journal_block_tag_s
{
	__be32		t_blocknr;	/* The on-disk block number */
	__be16		t_checksum;	/* truncated crc32c(uuid+seq+block) */
	__be16		t_flags;	/* See below */
	__be32		t_blocknr_high; /* most-significant high 32bits. */
} journal_block_tag_t;

/* Tail of descriptor or revoke block, for checksumming */
struct jbd2_journal_block_tail {
	__be32		t_checksum;	/* crc32c(uuid+descr_block) */
};

/*
 * The revoke descriptor: used on disk to describe a series of blocks to
 * be revoked from the log
 */
typedef struct jbd2_journal_revoke_header_s
{
	journal_header_t r_header;
	__be32		 r_count;	/* Count of bytes used in the block */
} jbd2_journal_revoke_header_t;

/* Definitions for the journal tag flags word: */
#define JBD2_FLAG_ESCAPE		1	/* on-disk block is escaped */
#define JBD2_FLAG_SAME_UUID	2	/* block has same uuid as previous */
#define JBD2_FLAG_DELETED	4	/* block deleted by this transaction */
#define JBD2_FLAG_LAST_TAG	8	/* last tag in this descriptor block */


/*
 * The journal superblock.  All fields are in big-endian byte order.
 */
typedef struct journal_superblock_s
{
/* 0x0000 */
	journal_header_t s_header;

/* 0x000C */
	/* Static information describing the journal */
	__be32	s_blocksize;		/* journal device blocksize */
	__be32	s_maxlen;		/* total blocks in journal file */
	__be32	s_first;		/* first block of log information */

/* 0x0018 */
	/* Dynamic information describing the current state of the log */
	__be32	s_sequence;		/* first commit ID expected in log */
	__be32	s_start;		/* blocknr of start of log */

/* 0x0020 */
	/* Error value, as set by jbd2_journal_abort(). */
	__be32	s_errno;

/* 0x0024 */
	/* Remaining fields are only valid in a version-2 superblock */
	__be32	s_feature_compat;	/* compatible feature set */
	__be32	s_feature_incompat;	/* incompatible feature set */
	__be32	s_feature_ro_compat;	/* readonly-compatible feature set */
/* 0x0030 */
	__u8	s_uuid[16];		/* 128-bit uuid for journal */

/* 0x0040 */
	__be32	s_nr_users;		/* Nr of filesystems sharing log */

	__be32	s_dynsuper;		/* Blocknr of dynamic superblock copy*/

/* 0x0048 */
	__be32	s_max_transaction;	/* Limit of journal blocks per trans.*/
	__be32	s_max_trans_data;	/* Limit of data blocks per trans. */

/* 0x0050 */
	__u8	s_checksum_type;	/* checksum type */
	__u8	s_padding2[3];
/* 0x0054 */
	__be32	s_num_fc_blks;		/* Number of fast commit blocks */
	__be32	s_head;			/* blocknr of head of log, only uptodate
					 * while the filesystem is clean */
/* 0x005C */
	__u32	s_padding[40];
	__be32	s_checksum;		/* crc32c(superblock) */

/* 0x0100 */
	__u8	s_users[16*48];		/* ids of all fs'es sharing the log */
/* 0x0400 */
} journal_superblock_t;

#define JBD2_FEATURE_COMPAT_CHECKSUM		0x00000001

#define JBD2_FEATURE_INCOMPAT_REVOKE		0x00000001
#define JBD2_FEATURE_INCOMPAT_64BIT		0x00000002
#define JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT	0x00000004
#define JBD2_FEATURE_INCOMPAT_CSUM_V2		0x00000008
#define JBD2_FEATURE_INCOMPAT_CSUM_V3		0x00000010
#define JBD2_FEATURE_INCOMPAT_FAST_COMMIT	0x00000020

/* See "journal feature predicate functions" below */

/* Features known to this kernel version: */
#define JBD2_KNOWN_COMPAT_FEATURES	JBD2_FEATURE_COMPAT_CHECKSUM
#define JBD2_KNOWN_ROCOMPAT_FEATURES	0
#define JBD2_KNOWN_INCOMPAT_FEATURES	(JBD2_FEATURE_INCOMPAT_REVOKE | \
					JBD2_FEATURE_INCOMPAT_64BIT | \
					JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT | \
					JBD2_FEATURE_INCOMPAT_CSUM_V2 | \
					JBD2_FEATURE_INCOMPAT_CSUM_V3 | \
					JBD2_FEATURE_INCOMPAT_FAST_COMMIT)

#ifdef __KERNEL__

#include <linux/fs.h>
#include <linux/sched.h>

enum jbd_state_bits {
	BH_JBD			/* Has an attached ext3 journal_head */
	  = BH_PrivateStart,
	BH_JWrite,		/* Being written to log (@@@ DEBUGGING) */
	BH_Freed,		/* Has been freed (truncated) */
	BH_Revoked,		/* Has been revoked from the log */
	BH_RevokeValid,		/* Revoked flag is valid */
	BH_JBDDirty,		/* Is dirty but journaled */
	BH_JournalHead,		/* Pins bh->b_private and jh->b_bh */
	BH_Shadow,		/* IO on shadow buffer is running */
	BH_Verified,		/* Metadata block has been verified ok */
	BH_JBDPrivateStart,	/* First bit available for private use by FS */
};

BUFFER_FNS(JBD, jbd)
BUFFER_FNS(JWrite, jwrite)
BUFFER_FNS(JBDDirty, jbddirty)
TAS_BUFFER_FNS(JBDDirty, jbddirty)
BUFFER_FNS(Revoked, revoked)
TAS_BUFFER_FNS(Revoked, revoked)
BUFFER_FNS(RevokeValid, revokevalid)
TAS_BUFFER_FNS(RevokeValid, revokevalid)
BUFFER_FNS(Freed, freed)
BUFFER_FNS(Shadow, shadow)
BUFFER_FNS(Verified, verified)

static inline struct buffer_head *jh2bh(struct journal_head *jh)
{
	return jh->b_bh;
}

static inline struct journal_head *bh2jh(struct buffer_head *bh)
{
	return bh->b_private;
}

static inline void jbd_lock_bh_journal_head(struct buffer_head *bh)
{
	bit_spin_lock(BH_JournalHead, &bh->b_state);
}

static inline void jbd_unlock_bh_journal_head(struct buffer_head *bh)
{
	bit_spin_unlock(BH_JournalHead, &bh->b_state);
}

#define J_ASSERT(assert)	BUG_ON(!(assert))

#define J_ASSERT_BH(bh, expr)	J_ASSERT(expr)
#define J_ASSERT_JH(jh, expr)	J_ASSERT(expr)

#if defined(JBD2_PARANOID_IOFAIL)
#define J_EXPECT(expr, why...)		J_ASSERT(expr)
#define J_EXPECT_BH(bh, expr, why...)	J_ASSERT_BH(bh, expr)
#define J_EXPECT_JH(jh, expr, why...)	J_ASSERT_JH(jh, expr)
#else
#define __journal_expect(expr, why...)					     \
	({								     \
		int val = (expr);					     \
		if (!val) {						     \
			printk(KERN_ERR					     \
			       "JBD2 unexpected failure: %s: %s;\n",	     \
			       __func__, #expr);			     \
			printk(KERN_ERR why "\n");			     \
		}							     \
		val;							     \
	})
#define J_EXPECT(expr, why...)		__journal_expect(expr, ## why)
#define J_EXPECT_BH(bh, expr, why...)	__journal_expect(expr, ## why)
#define J_EXPECT_JH(jh, expr, why...)	__journal_expect(expr, ## why)
#endif

/* Flags in jbd_inode->i_flags */
#define __JI_COMMIT_RUNNING 0
#define __JI_WRITE_DATA 1
#define __JI_WAIT_DATA 2

/*
 * Commit of the inode data in progress. We use this flag to protect us from
 * concurrent deletion of inode. We cannot use reference to inode for this
 * since we cannot afford doing last iput() on behalf of kjournald
 */
#define JI_COMMIT_RUNNING (1 << __JI_COMMIT_RUNNING)
/* Write allocated dirty buffers in this inode before commit */
#define JI_WRITE_DATA (1 << __JI_WRITE_DATA)
/* Wait for outstanding data writes for this inode before commit */
#define JI_WAIT_DATA (1 << __JI_WAIT_DATA)

/**
 * struct jbd2_inode - The jbd_inode type is the structure linking inodes in
 * ordered mode present in a transaction so that we can sync them during commit.
 */
struct jbd2_inode {
	/**
	 * @i_transaction:
	 *
	 * Which transaction does this inode belong to? Either the running
	 * transaction or the committing one. [j_list_lock]
	 */
	transaction_t *i_transaction;

	/**
	 * @i_next_transaction:
	 *
	 * Pointer to the running transaction modifying inode's data in case
	 * there is already a committing transaction touching it. [j_list_lock]
	 */
	transaction_t *i_next_transaction;

	/**
	 * @i_list: List of inodes in the i_transaction [j_list_lock]
	 */
	struct list_head i_list;

	/**
	 * @i_vfs_inode:
	 *
	 * VFS inode this inode belongs to [constant for lifetime of structure]
	 */
	struct inode *i_vfs_inode;

	/**
	 * @i_flags: Flags of inode [j_list_lock]
	 */
	unsigned long i_flags;

	/**
	 * @i_dirty_start:
	 *
	 * Offset in bytes where the dirty range for this inode starts.
	 * [j_list_lock]
	 */
	loff_t i_dirty_start;

	/**
	 * @i_dirty_end:
	 *
	 * Inclusive offset in bytes where the dirty range for this inode
	 * ends. [j_list_lock]
	 */
	loff_t i_dirty_end;
};

struct jbd2_revoke_table_s;

/**
 * struct jbd2_journal_handle - The jbd2_journal_handle type is the concrete
 *     type associated with handle_t.
 * @h_transaction: Which compound transaction is this update a part of?
 * @h_journal: Which journal handle belongs to - used iff h_reserved set.
 * @h_rsv_handle: Handle reserved for finishing the logical operation.
 * @h_total_credits: Number of remaining buffers we are allowed to add to
 *	journal. These are dirty buffers and revoke descriptor blocks.
 * @h_revoke_credits: Number of remaining revoke records available for handle
 * @h_ref: Reference count on this handle.
 * @h_err: Field for caller's use to track errors through large fs operations.
 * @h_sync: Flag for sync-on-close.
 * @h_jdata: Flag to force data journaling.
 * @h_reserved: Flag for handle for reserved credits.
 * @h_aborted: Flag indicating fatal error on handle.
 * @h_type: For handle statistics.
 * @h_line_no: For handle statistics.
 * @h_start_jiffies: Handle Start time.
 * @h_requested_credits: Holds @h_total_credits after handle is started.
 * @h_revoke_credits_requested: Holds @h_revoke_credits after handle is started.
 * @saved_alloc_context: Saved context while transaction is open.
 **/

/* Docbook can't yet cope with the bit fields, but will leave the documentation
 * in so it can be fixed later.
 */

struct jbd2_journal_handle
{
	union {
		transaction_t	*h_transaction;
		/* Which journal handle belongs to - used iff h_reserved set */
		journal_t	*h_journal;
	};

	handle_t		*h_rsv_handle;
	int			h_total_credits;
	int			h_revoke_credits;
	int			h_revoke_credits_requested;
	int			h_ref;
	int			h_err;

	/* Flags [no locking] */
	unsigned int	h_sync:		1;
	unsigned int	h_jdata:	1;
	unsigned int	h_reserved:	1;
	unsigned int	h_aborted:	1;
	unsigned int	h_type:		8;
	unsigned int	h_line_no:	16;

	unsigned long		h_start_jiffies;
	unsigned int		h_requested_credits;

	unsigned int		saved_alloc_context;
};


/*
 * Some stats for checkpoint phase
 */
struct transaction_chp_stats_s {
	unsigned long		cs_chp_time;
	__u32			cs_forced_to_close;
	__u32			cs_written;
	__u32			cs_dropped;
};

/* The transaction_t type is the guts of the journaling mechanism.  It
 * tracks a compound transaction through its various states:
 *
 * RUNNING:	accepting new updates
 * LOCKED:	Updates still running but we don't accept new ones
 * RUNDOWN:	Updates are tidying up but have finished requesting
 *		new buffers to modify (state not used for now)
 * FLUSH:       All updates complete, but we are still writing to disk
 * COMMIT:      All data on disk, writing commit record
 * FINISHED:	We still have to keep the transaction for checkpointing.
 *
 * The transaction keeps track of all of the buffers modified by a
 * running transaction, and all of the buffers committed but not yet
 * flushed to home for finished transactions.
 * (Locking Documentation improved by LockDoc)
 */

/*
 * Lock ranking:
 *
 *    j_list_lock
 *      ->jbd_lock_bh_journal_head()	(This is "innermost")
 *
 *    j_state_lock
 *    ->b_state_lock
 *
 *    b_state_lock
 *    ->j_list_lock
 *
 *    j_state_lock
 *    ->j_list_lock			(journal_unmap_buffer)
 *
 */

struct transaction_s
{
	/* Pointer to the journal for this transaction. [no locking] */
	journal_t		*t_journal;

	/* Sequence number for this transaction [no locking] */
	tid_t			t_tid;

	/*
	 * Transaction's current state
	 * [no locking - only kjournald2 alters this]
	 * [j_list_lock] guards transition of a transaction into T_FINISHED
	 * state and subsequent call of __jbd2_journal_drop_transaction()
	 * FIXME: needs barriers
	 * KLUDGE: [use j_state_lock]
	 */
	enum {
		T_RUNNING,
		T_LOCKED,
		T_SWITCH,
		T_FLUSH,
		T_COMMIT,
		T_COMMIT_DFLUSH,
		T_COMMIT_JFLUSH,
		T_COMMIT_CALLBACK,
		T_FINISHED
	}			t_state;

	/*
	 * Where in the log does this transaction's commit start? [no locking]
	 */
	unsigned long		t_log_start;

	/*
	 * Number of buffers on the t_buffers list [j_list_lock, no locks
	 * needed for jbd2 thread]
	 */
	int			t_nr_buffers;

	/*
	 * Doubly-linked circular list of all buffers reserved but not yet
	 * modified by this transaction [j_list_lock, no locks needed fo
	 * jbd2 thread]
	 */
	struct journal_head	*t_reserved_list;

	/*
	 * Doubly-linked circular list of all metadata buffers owned by this
	 * transaction [j_list_lock, no locks needed for jbd2 thread]
	 */
	struct journal_head	*t_buffers;

	/*
	 * Doubly-linked circular list of all forget buffers (superseded
	 * buffers which we can un-checkpoint once this transaction commits)
	 * [j_list_lock]
	 */
	struct journal_head	*t_forget;

	/*
	 * Doubly-linked circular list of all buffers still to be flushed before
	 * this transaction can be checkpointed. [j_list_lock]
	 */
	struct journal_head	*t_checkpoint_list;

	/*
	 * Doubly-linked circular list of metadata buffers being
	 * shadowed by log IO.  The IO buffers on the iobuf list and
	 * the shadow buffers on this list match each other one for
	 * one at all times. [j_list_lock, no locks needed for jbd2
	 * thread]
	 */
	struct journal_head	*t_shadow_list;

	/*
	 * List of inodes associated with the transaction; e.g., ext4 uses
	 * this to track inodes in data=ordered and data=journal mode that
	 * need special handling on transaction commit; also used by ocfs2.
	 * [j_list_lock]
	 */
	struct list_head	t_inode_list;

	/*
	 * Longest time some handle had to wait for running transaction
	 */
	unsigned long		t_max_wait;

	/*
	 * When transaction started
	 */
	unsigned long		t_start;

	/*
	 * When commit was requested [j_state_lock]
	 */
	unsigned long		t_requested;

	/*
	 * Checkpointing stats [j_list_lock]
	 */
	struct transaction_chp_stats_s t_chp_stats;

	/*
	 * Number of outstanding updates running on this transaction
	 * [none]
	 */
	atomic_t		t_updates;

	/*
	 * Number of blocks reserved for this transaction in the journal.
	 * This is including all credits reserved when starting transaction
	 * handles as well as all journal descriptor blocks needed for this
	 * transaction. [none]
	 */
	atomic_t		t_outstanding_credits;

	/*
	 * Number of revoke records for this transaction added by already
	 * stopped handles. [none]
	 */
	atomic_t		t_outstanding_revokes;

	/*
	 * How many handles used this transaction? [none]
	 */
	atomic_t		t_handle_count;

	/*
	 * Forward and backward links for the circular list of all transactions
	 * awaiting checkpoint. [j_list_lock]
	 */
	transaction_t		*t_cpnext, *t_cpprev;

	/*
	 * When will the transaction expire (become due for commit), in jiffies?
	 * [no locking]
	 */
	unsigned long		t_expires;

	/*
	 * When this transaction started, in nanoseconds [no locking]
	 */
	ktime_t			t_start_time;

	/*
	 * This transaction is being forced and some process is
	 * waiting for it to finish.
	 */
	unsigned int t_synchronous_commit:1;

	/* Disk flush needs to be sent to fs partition [no locking] */
	int			t_need_data_flush;

	/*
	 * For use by the filesystem to store fs-specific data
	 * structures associated with the transaction
	 */
	struct list_head	t_private_list;
};

struct transaction_run_stats_s {
	unsigned long		rs_wait;
	unsigned long		rs_request_delay;
	unsigned long		rs_running;
	unsigned long		rs_locked;
	unsigned long		rs_flushing;
	unsigned long		rs_logging;

	__u32			rs_handle_count;
	__u32			rs_blocks;
	__u32			rs_blocks_logged;
};

struct transaction_stats_s {
	unsigned long		ts_tid;
	unsigned long		ts_requested;
	struct transaction_run_stats_s run;
};

static inline unsigned long
jbd2_time_diff(unsigned long start, unsigned long end)
{
	if (end >= start)
		return end - start;

	return end + (MAX_JIFFY_OFFSET - start);
}

#define JBD2_NR_BATCH	64

enum passtype {PASS_SCAN, PASS_REVOKE, PASS_REPLAY};

#define JBD2_FC_REPLAY_STOP	0
#define JBD2_FC_REPLAY_CONTINUE	1

/**
 * struct journal_s - The journal_s type is the concrete type associated with
 *     journal_t.
 */
struct journal_s
{
	/**
	 * @j_flags: General journaling state flags [j_state_lock,
	 * no lock for quick racy checks]
	 */
	unsigned long		j_flags;

	/**
	 * @j_errno:
	 *
	 * Is there an outstanding uncleared error on the journal (from a prior
	 * abort)? [j_state_lock]
	 */
	int			j_errno;

	/**
	 * @j_abort_mutex: Lock the whole aborting procedure.
	 */
	struct mutex		j_abort_mutex;

	/**
	 * @j_sb_buffer: The first part of the superblock buffer.
	 */
	struct buffer_head	*j_sb_buffer;

	/**
	 * @j_superblock: The second part of the superblock buffer.
	 */
	journal_superblock_t	*j_superblock;

	/**
	 * @j_state_lock: Protect the various scalars in the journal.
	 */
	rwlock_t		j_state_lock;

	/**
	 * @j_barrier_count:
	 *
	 * Number of processes waiting to create a barrier lock [j_state_lock,
	 * no lock for quick racy checks]
	 */
	int			j_barrier_count;

	/**
	 * @j_barrier: The barrier lock itself.
	 */
	struct mutex		j_barrier;

	/**
	 * @j_running_transaction:
	 *
	 * Transactions: The current running transaction...
	 * [j_state_lock, no lock for quick racy checks] [caller holding
	 * open handle]
	 */
	transaction_t		*j_running_transaction;

	/**
	 * @j_committing_transaction:
	 *
	 * the transaction we are pushing to disk
	 * [j_state_lock] [caller holding open handle]
	 */
	transaction_t		*j_committing_transaction;

	/**
	 * @j_checkpoint_transactions:
	 *
	 * ... and a linked circular list of all transactions waiting for
	 * checkpointing. [j_list_lock]
	 */
	transaction_t		*j_checkpoint_transactions;

	/**
	 * @j_wait_transaction_locked:
	 *
	 * Wait queue for waiting for a locked transaction to start committing,
	 * or for a barrier lock to be released.
	 */
	wait_queue_head_t	j_wait_transaction_locked;

	/**
	 * @j_wait_done_commit: Wait queue for waiting for commit to complete.
	 */
	wait_queue_head_t	j_wait_done_commit;

	/**
	 * @j_wait_commit: Wait queue to trigger commit.
	 */
	wait_queue_head_t	j_wait_commit;

	/**
	 * @j_wait_updates: Wait queue to wait for updates to complete.
	 */
	wait_queue_head_t	j_wait_updates;

	/**
	 * @j_wait_reserved:
	 *
	 * Wait queue to wait for reserved buffer credits to drop.
	 */
	wait_queue_head_t	j_wait_reserved;

	/**
	 * @j_fc_wait:
	 *
	 * Wait queue to wait for completion of async fast commits.
	 */
	wait_queue_head_t	j_fc_wait;

	/**
	 * @j_checkpoint_mutex:
	 *
	 * Semaphore for locking against concurrent checkpoints.
	 */
	struct mutex		j_checkpoint_mutex;

	/**
	 * @j_chkpt_bhs:
	 *
	 * List of buffer heads used by the checkpoint routine.  This
	 * was moved from jbd2_log_do_checkpoint() to reduce stack
	 * usage.  Access to this array is controlled by the
	 * @j_checkpoint_mutex.  [j_checkpoint_mutex]
	 */
	struct buffer_head	*j_chkpt_bhs[JBD2_NR_BATCH];

	/**
	 * @j_shrinker:
	 *
	 * Journal head shrinker, reclaim buffer's journal head which
	 * has been written back.
	 */
	struct shrinker		*j_shrinker;

	/**
	 * @j_checkpoint_jh_count:
	 *
	 * Number of journal buffers on the checkpoint list. [j_list_lock]
	 */
	struct percpu_counter	j_checkpoint_jh_count;

	/**
	 * @j_shrink_transaction:
	 *
	 * Record next transaction will shrink on the checkpoint list.
	 * [j_list_lock]
	 */
	transaction_t		*j_shrink_transaction;

	/**
	 * @j_head:
	 *
	 * Journal head: identifies the first unused block in the journal.
	 * [j_state_lock]
	 */
	unsigned long		j_head;

	/**
	 * @j_tail:
	 *
	 * Journal tail: identifies the oldest still-used block in the journal.
	 * [j_state_lock]
	 */
	unsigned long		j_tail;

	/**
	 * @j_free:
	 *
	 * Journal free: how many free blocks are there in the journal?
	 * [j_state_lock]
	 */
	unsigned long		j_free;

	/**
	 * @j_first:
	 *
	 * The block number of the first usable block in the journal
	 * [j_state_lock].
	 */
	unsigned long		j_first;

	/**
	 * @j_last:
	 *
	 * The block number one beyond the last usable block in the journal
	 * [j_state_lock].
	 */
	unsigned long		j_last;

	/**
	 * @j_fc_first:
	 *
	 * The block number of the first fast commit block in the journal
	 * [j_state_lock].
	 */
	unsigned long		j_fc_first;

	/**
	 * @j_fc_off:
	 *
	 * Number of fast commit blocks currently allocated. Accessed only
	 * during fast commit. Currently only process can do fast commit, so
	 * this field is not protected by any lock.
	 */
	unsigned long		j_fc_off;

	/**
	 * @j_fc_last:
	 *
	 * The block number one beyond the last fast commit block in the journal
	 * [j_state_lock].
	 */
	unsigned long		j_fc_last;

	/**
	 * @j_dev: Device where we store the journal.
	 */
	struct block_device	*j_dev;

	/**
	 * @j_blocksize: Block size for the location where we store the journal.
	 */
	int			j_blocksize;

	/**
	 * @j_blk_offset:
	 *
	 * Starting block offset into the device where we store the journal.
	 */
	unsigned long long	j_blk_offset;

	/**
	 * @j_devname: Journal device name.
	 */
	char			j_devname[BDEVNAME_SIZE+24];

	/**
	 * @j_fs_dev:
	 *
	 * Device which holds the client fs.  For internal journal this will be
	 * equal to j_dev.
	 */
	struct block_device	*j_fs_dev;

	/**
	 * @j_fs_dev_wb_err:
	 *
	 * Records the errseq of the client fs's backing block device.
	 */
	errseq_t		j_fs_dev_wb_err;

	/**
	 * @j_total_len: Total maximum capacity of the journal region on disk.
	 */
	unsigned int		j_total_len;

	/**
	 * @j_reserved_credits:
	 *
	 * Number of buffers reserved from the running transaction.
	 */
	atomic_t		j_reserved_credits;

	/**
	 * @j_list_lock: Protects the buffer lists and internal buffer state.
	 */
	spinlock_t		j_list_lock;

	/**
	 * @j_inode:
	 *
	 * Optional inode where we store the journal.  If present, all
	 * journal block numbers are mapped into this inode via bmap().
	 */
	struct inode		*j_inode;

	/**
	 * @j_tail_sequence:
	 *
	 * Sequence number of the oldest transaction in the log [j_state_lock]
	 */
	tid_t			j_tail_sequence;

	/**
	 * @j_transaction_sequence:
	 *
	 * Sequence number of the next transaction to grant [j_state_lock]
	 */
	tid_t			j_transaction_sequence;

	/**
	 * @j_commit_sequence:
	 *
	 * Sequence number of the most recently committed transaction
	 * [j_state_lock, no lock for quick racy checks]
	 */
	tid_t			j_commit_sequence;

	/**
	 * @j_commit_request:
	 *
	 * Sequence number of the most recent transaction wanting commit
	 * [j_state_lock, no lock for quick racy checks]
	 */
	tid_t			j_commit_request;

	/**
	 * @j_uuid:
	 *
	 * Journal uuid: identifies the object (filesystem, LVM volume etc)
	 * backed by this journal.  This will eventually be replaced by an array
	 * of uuids, allowing us to index multiple devices within a single
	 * journal and to perform atomic updates across them.
	 */
	__u8			j_uuid[16];

	/**
	 * @j_task: Pointer to the current commit thread for this journal.
	 */
	struct task_struct	*j_task;

	/**
	 * @j_max_transaction_buffers:
	 *
	 * Maximum number of metadata buffers to allow in a single compound
	 * commit transaction.
	 */
	int			j_max_transaction_buffers;

	/**
	 * @j_revoke_records_per_block:
	 *
	 * Number of revoke records that fit in one descriptor block.
	 */
	int			j_revoke_records_per_block;

	/**
	 * @j_transaction_overhead_buffers:
	 *
	 * Number of blocks each transaction needs for its own bookkeeping
	 */
	int			j_transaction_overhead_buffers;

	/**
	 * @j_commit_interval:
	 *
	 * What is the maximum transaction lifetime before we begin a commit?
	 */
	unsigned long		j_commit_interval;

	/**
	 * @j_commit_timer: The timer used to wakeup the commit thread.
	 */
	struct timer_list	j_commit_timer;

	/**
	 * @j_revoke_lock: Protect the revoke table.
	 */
	spinlock_t		j_revoke_lock;

	/**
	 * @j_revoke:
	 *
	 * The revoke table - maintains the list of revoked blocks in the
	 * current transaction.
	 */
	struct jbd2_revoke_table_s *j_revoke;

	/**
	 * @j_revoke_table: Alternate revoke tables for j_revoke.
	 */
	struct jbd2_revoke_table_s *j_revoke_table[2];

	/**
	 * @j_wbuf: Array of bhs for jbd2_journal_commit_transaction.
	 */
	struct buffer_head	**j_wbuf;

	/**
	 * @j_fc_wbuf: Array of fast commit bhs for fast commit. Accessed only
	 * during a fast commit. Currently only process can do fast commit, so
	 * this field is not protected by any lock.
	 */
	struct buffer_head	**j_fc_wbuf;

	/**
	 * @j_wbufsize:
	 *
	 * Size of @j_wbuf array.
	 */
	int			j_wbufsize;

	/**
	 * @j_fc_wbufsize:
	 *
	 * Size of @j_fc_wbuf array.
	 */
	int			j_fc_wbufsize;

	/**
	 * @j_last_sync_writer:
	 *
	 * The pid of the last person to run a synchronous operation
	 * through the journal.
	 */
	pid_t			j_last_sync_writer;

	/**
	 * @j_average_commit_time:
	 *
	 * The average amount of time in nanoseconds it takes to commit a
	 * transaction to disk. [j_state_lock]
	 */
	u64			j_average_commit_time;

	/**
	 * @j_min_batch_time:
	 *
	 * Minimum time that we should wait for additional filesystem operations
	 * to get batched into a synchronous handle in microseconds.
	 */
	u32			j_min_batch_time;

	/**
	 * @j_max_batch_time:
	 *
	 * Maximum time that we should wait for additional filesystem operations
	 * to get batched into a synchronous handle in microseconds.
	 */
	u32			j_max_batch_time;

	/**
	 * @j_commit_callback:
	 *
	 * This function is called when a transaction is closed.
	 */
	void			(*j_commit_callback)(journal_t *,
						     transaction_t *);

	/**
	 * @j_submit_inode_data_buffers:
	 *
	 * This function is called for all inodes associated with the
	 * committing transaction marked with JI_WRITE_DATA flag
	 * before we start to write out the transaction to the journal.
	 */
	int			(*j_submit_inode_data_buffers)
					(struct jbd2_inode *);

	/**
	 * @j_finish_inode_data_buffers:
	 *
	 * This function is called for all inodes associated with the
	 * committing transaction marked with JI_WAIT_DATA flag
	 * after we have written the transaction to the journal
	 * but before we write out the commit block.
	 */
	int			(*j_finish_inode_data_buffers)
					(struct jbd2_inode *);

	/*
	 * Journal statistics
	 */

	/**
	 * @j_history_lock: Protect the transactions statistics history.
	 */
	spinlock_t		j_history_lock;

	/**
	 * @j_proc_entry: procfs entry for the jbd statistics directory.
	 */
	struct proc_dir_entry	*j_proc_entry;

	/**
	 * @j_stats: Overall statistics.
	 */
	struct transaction_stats_s j_stats;

	/**
	 * @j_failed_commit: Failed journal commit ID.
	 */
	unsigned int		j_failed_commit;

	/**
	 * @j_private:
	 *
	 * An opaque pointer to fs-private information.  ext3 puts its
	 * superblock pointer here.
	 */
	void *j_private;

	/**
	 * @j_chksum_driver:
	 *
	 * Reference to checksum algorithm driver via cryptoapi.
	 */
	struct crypto_shash *j_chksum_driver;

	/**
	 * @j_csum_seed:
	 *
	 * Precomputed journal UUID checksum for seeding other checksums.
	 */
	__u32 j_csum_seed;

#ifdef CONFIG_DEBUG_LOCK_ALLOC
	/**
	 * @j_trans_commit_map:
	 *
	 * Lockdep entity to track transaction commit dependencies. Handles
	 * hold this "lock" for read, when we wait for commit, we acquire the
	 * "lock" for writing. This matches the properties of jbd2 journalling
	 * where the running transaction has to wait for all handles to be
	 * dropped to commit that transaction and also acquiring a handle may
	 * require transaction commit to finish.
	 */
	struct lockdep_map	j_trans_commit_map;
#endif

	/**
	 * @j_fc_cleanup_callback:
	 *
	 * Clean-up after fast commit or full commit. JBD2 calls this function
	 * after every commit operation.
	 */
	void (*j_fc_cleanup_callback)(struct journal_s *journal, int full, tid_t tid);

	/**
	 * @j_fc_replay_callback:
	 *
	 * File-system specific function that performs replay of a fast
	 * commit. JBD2 calls this function for each fast commit block found in
	 * the journal. This function should return JBD2_FC_REPLAY_CONTINUE
	 * to indicate that the block was processed correctly and more fast
	 * commit replay should continue. Return value of JBD2_FC_REPLAY_STOP
	 * indicates the end of replay (no more blocks remaining). A negative
	 * return value indicates error.
	 */
	int (*j_fc_replay_callback)(struct journal_s *journal,
				    struct buffer_head *bh,
				    enum passtype pass, int off,
				    tid_t expected_commit_id);

	/**
	 * @j_bmap:
	 *
	 * Bmap function that should be used instead of the generic
	 * VFS bmap function.
	 */
	int (*j_bmap)(struct journal_s *journal, sector_t *block);
};

#define jbd2_might_wait_for_commit(j) \
	do { \
		rwsem_acquire(&j->j_trans_commit_map, 0, 0, _THIS_IP_); \
		rwsem_release(&j->j_trans_commit_map, _THIS_IP_); \
	} while (0)

/*
 * We can support any known requested features iff the
 * superblock is not in version 1.  Otherwise we fail to support any
 * extended sb features.
 */
static inline bool jbd2_format_support_feature(journal_t *j)
{
	return j->j_superblock->s_header.h_blocktype !=
					cpu_to_be32(JBD2_SUPERBLOCK_V1);
}

/* journal feature predicate functions */
#define JBD2_FEATURE_COMPAT_FUNCS(name, flagname) \
static inline bool jbd2_has_feature_##name(journal_t *j) \
{ \
	return (jbd2_format_support_feature(j) && \
		((j)->j_superblock->s_feature_compat & \
		 cpu_to_be32(JBD2_FEATURE_COMPAT_##flagname)) != 0); \
} \
static inline void jbd2_set_feature_##name(journal_t *j) \
{ \
	(j)->j_superblock->s_feature_compat |= \
		cpu_to_be32(JBD2_FEATURE_COMPAT_##flagname); \
} \
static inline void jbd2_clear_feature_##name(journal_t *j) \
{ \
	(j)->j_superblock->s_feature_compat &= \
		~cpu_to_be32(JBD2_FEATURE_COMPAT_##flagname); \
}

#define JBD2_FEATURE_RO_COMPAT_FUNCS(name, flagname) \
static inline bool jbd2_has_feature_##name(journal_t *j) \
{ \
	return (jbd2_format_support_feature(j) && \
		((j)->j_superblock->s_feature_ro_compat & \
		 cpu_to_be32(JBD2_FEATURE_RO_COMPAT_##flagname)) != 0); \
} \
static inline void jbd2_set_feature_##name(journal_t *j) \
{ \
	(j)->j_superblock->s_feature_ro_compat |= \
		cpu_to_be32(JBD2_FEATURE_RO_COMPAT_##flagname); \
} \
static inline void jbd2_clear_feature_##name(journal_t *j) \
{ \
	(j)->j_superblock->s_feature_ro_compat &= \
		~cpu_to_be32(JBD2_FEATURE_RO_COMPAT_##flagname); \
}

#define JBD2_FEATURE_INCOMPAT_FUNCS(name, flagname) \
static inline bool jbd2_has_feature_##name(journal_t *j) \
{ \
	return (jbd2_format_support_feature(j) && \
		((j)->j_superblock->s_feature_incompat & \
		 cpu_to_be32(JBD2_FEATURE_INCOMPAT_##flagname)) != 0); \
} \
static inline void jbd2_set_feature_##name(journal_t *j) \
{ \
	(j)->j_superblock->s_feature_incompat |= \
		cpu_to_be32(JBD2_FEATURE_INCOMPAT_##flagname); \
} \
static inline void jbd2_clear_feature_##name(journal_t *j) \
{ \
	(j)->j_superblock->s_feature_incompat &= \
		~cpu_to_be32(JBD2_FEATURE_INCOMPAT_##flagname); \
}

JBD2_FEATURE_COMPAT_FUNCS(checksum,		CHECKSUM)

JBD2_FEATURE_INCOMPAT_FUNCS(revoke,		REVOKE)
JBD2_FEATURE_INCOMPAT_FUNCS(64bit,		64BIT)
JBD2_FEATURE_INCOMPAT_FUNCS(async_commit,	ASYNC_COMMIT)
JBD2_FEATURE_INCOMPAT_FUNCS(csum2,		CSUM_V2)
JBD2_FEATURE_INCOMPAT_FUNCS(csum3,		CSUM_V3)
JBD2_FEATURE_INCOMPAT_FUNCS(fast_commit,	FAST_COMMIT)

/* Journal high priority write IO operation flags */
#define JBD2_JOURNAL_REQ_FLAGS		(REQ_META | REQ_SYNC | REQ_IDLE)

/*
 * Journal flag definitions
 */
#define JBD2_UNMOUNT	0x001	/* Journal thread is being destroyed */
#define JBD2_ABORT	0x002	/* Journaling has been aborted for errors. */
#define JBD2_ACK_ERR	0x004	/* The errno in the sb has been acked */
#define JBD2_FLUSHED	0x008	/* The journal superblock has been flushed */
#define JBD2_LOADED	0x010	/* The journal superblock has been loaded */
#define JBD2_BARRIER	0x020	/* Use IDE barriers */
#define JBD2_ABORT_ON_SYNCDATA_ERR	0x040	/* Abort the journal on file
						 * data write error in ordered
						 * mode */
#define JBD2_CYCLE_RECORD		0x080	/* Journal cycled record log on
						 * clean and empty filesystem
						 * logging area */
#define JBD2_FAST_COMMIT_ONGOING	0x100	/* Fast commit is ongoing */
#define JBD2_FULL_COMMIT_ONGOING	0x200	/* Full commit is ongoing */
#define JBD2_JOURNAL_FLUSH_DISCARD	0x0001
#define JBD2_JOURNAL_FLUSH_ZEROOUT	0x0002
#define JBD2_JOURNAL_FLUSH_VALID	(JBD2_JOURNAL_FLUSH_DISCARD | \
					JBD2_JOURNAL_FLUSH_ZEROOUT)

/*
 * Function declarations for the journaling transaction and buffer
 * management
 */

/* Filing buffers */
extern void jbd2_journal_unfile_buffer(journal_t *, struct journal_head *);
extern bool __jbd2_journal_refile_buffer(struct journal_head *);
extern void jbd2_journal_refile_buffer(journal_t *, struct journal_head *);
extern void __jbd2_journal_file_buffer(struct journal_head *, transaction_t *, int);
extern void jbd2_journal_file_buffer(struct journal_head *, transaction_t *, int);
static inline void jbd2_file_log_bh(struct list_head *head, struct buffer_head *bh)
{
	list_add_tail(&bh->b_assoc_buffers, head);
}
static inline void jbd2_unfile_log_bh(struct buffer_head *bh)
{
	list_del_init(&bh->b_assoc_buffers);
}

/* Log buffer allocation */
struct buffer_head *jbd2_journal_get_descriptor_buffer(transaction_t *, int);
void jbd2_descriptor_block_csum_set(journal_t *, struct buffer_head *);
int jbd2_journal_next_log_block(journal_t *, unsigned long long *);
int jbd2_journal_get_log_tail(journal_t *journal, tid_t *tid,
			      unsigned long *block);
int __jbd2_update_log_tail(journal_t *journal, tid_t tid, unsigned long block);
void jbd2_update_log_tail(journal_t *journal, tid_t tid, unsigned long block);

/* Commit management */
extern void jbd2_journal_commit_transaction(journal_t *);

/* Checkpoint list management */
void __jbd2_journal_clean_checkpoint_list(journal_t *journal, bool destroy);
unsigned long jbd2_journal_shrink_checkpoint_list(journal_t *journal, unsigned long *nr_to_scan);
int __jbd2_journal_remove_checkpoint(struct journal_head *);
int jbd2_journal_try_remove_checkpoint(struct journal_head *jh);
void jbd2_journal_destroy_checkpoint(journal_t *journal);
void __jbd2_journal_insert_checkpoint(struct journal_head *, transaction_t *);


/*
 * Triggers
 */

struct jbd2_buffer_trigger_type {
	/*
	 * Fired a the moment data to write to the journal are known to be
	 * stable - so either at the moment b_frozen_data is created or just
	 * before a buffer is written to the journal.  mapped_data is a mapped
	 * buffer that is the frozen data for commit.
	 */
	void (*t_frozen)(struct jbd2_buffer_trigger_type *type,
			 struct buffer_head *bh, void *mapped_data,
			 size_t size);

	/*
	 * Fired during journal abort for dirty buffers that will not be
	 * committed.
	 */
	void (*t_abort)(struct jbd2_buffer_trigger_type *type,
			struct buffer_head *bh);
};

extern void jbd2_buffer_frozen_trigger(struct journal_head *jh,
				       void *mapped_data,
				       struct jbd2_buffer_trigger_type *triggers);
extern void jbd2_buffer_abort_trigger(struct journal_head *jh,
				      struct jbd2_buffer_trigger_type *triggers);

/* Buffer IO */
extern int jbd2_journal_write_metadata_buffer(transaction_t *transaction,
					      struct journal_head *jh_in,
					      struct buffer_head **bh_out,
					      sector_t blocknr);

/* Transaction cache support */
extern void jbd2_journal_destroy_transaction_cache(void);
extern int __init jbd2_journal_init_transaction_cache(void);
extern void jbd2_journal_free_transaction(transaction_t *);

/*
 * Journal locking.
 *
 * We need to lock the journal during transaction state changes so that nobody
 * ever tries to take a handle on the running transaction while we are in the
 * middle of moving it to the commit phase.  j_state_lock does this.
 *
 * Note that the locking is completely interrupt unsafe.  We never touch
 * journal structures from interrupts.
 */

static inline handle_t *journal_current_handle(void)
{
	return current->journal_info;
}

/* The journaling code user interface:
 *
 * Create and destroy handles
 * Register buffer modifications against the current transaction.
 */

extern handle_t *jbd2_journal_start(journal_t *, int nblocks);
extern handle_t *jbd2__journal_start(journal_t *, int blocks, int rsv_blocks,
				     int revoke_records, gfp_t gfp_mask,
				     unsigned int type, unsigned int line_no);
extern int	 jbd2_journal_restart(handle_t *, int nblocks);
extern int	 jbd2__journal_restart(handle_t *, int nblocks,
				       int revoke_records, gfp_t gfp_mask);
extern int	 jbd2_journal_start_reserved(handle_t *handle,
				unsigned int type, unsigned int line_no);
extern void	 jbd2_journal_free_reserved(handle_t *handle);
extern int	 jbd2_journal_extend(handle_t *handle, int nblocks,
				     int revoke_records);
extern int	 jbd2_journal_get_write_access(handle_t *, struct buffer_head *);
extern int	 jbd2_journal_get_create_access (handle_t *, struct buffer_head *);
extern int	 jbd2_journal_get_undo_access(handle_t *, struct buffer_head *);
void		 jbd2_journal_set_triggers(struct buffer_head *,
					   struct jbd2_buffer_trigger_type *type);
extern int	 jbd2_journal_dirty_metadata (handle_t *, struct buffer_head *);
extern int	 jbd2_journal_forget (handle_t *, struct buffer_head *);
int jbd2_journal_invalidate_folio(journal_t *, struct folio *,
					size_t offset, size_t length);
bool jbd2_journal_try_to_free_buffers(journal_t *journal, struct folio *folio);
extern int	 jbd2_journal_stop(handle_t *);
extern int	 jbd2_journal_flush(journal_t *journal, unsigned int flags);
extern void	 jbd2_journal_lock_updates (journal_t *);
extern void	 jbd2_journal_unlock_updates (journal_t *);

void jbd2_journal_wait_updates(journal_t *);

extern journal_t * jbd2_journal_init_dev(struct block_device *bdev,
				struct block_device *fs_dev,
				unsigned long long start, int len, int bsize);
extern journal_t * jbd2_journal_init_inode (struct inode *);
extern int	   jbd2_journal_update_format (journal_t *);
extern int	   jbd2_journal_check_used_features
		   (journal_t *, unsigned long, unsigned long, unsigned long);
extern int	   jbd2_journal_check_available_features
		   (journal_t *, unsigned long, unsigned long, unsigned long);
extern int	   jbd2_journal_set_features
		   (journal_t *, unsigned long, unsigned long, unsigned long);
extern void	   jbd2_journal_clear_features
		   (journal_t *, unsigned long, unsigned long, unsigned long);
extern int	   jbd2_journal_load       (journal_t *journal);
extern int	   jbd2_journal_destroy    (journal_t *);
extern int	   jbd2_journal_recover    (journal_t *journal);
extern int	   jbd2_journal_wipe       (journal_t *, int);
extern int	   jbd2_journal_skip_recovery	(journal_t *);
extern void	   jbd2_journal_update_sb_errno(journal_t *);
extern int	   jbd2_journal_update_sb_log_tail	(journal_t *, tid_t,
				unsigned long, blk_opf_t);
extern void	   jbd2_journal_abort      (journal_t *, int);
extern int	   jbd2_journal_errno      (journal_t *);
extern void	   jbd2_journal_ack_err    (journal_t *);
extern int	   jbd2_journal_clear_err  (journal_t *);
extern int	   jbd2_journal_bmap(journal_t *, unsigned long, unsigned long long *);
extern int	   jbd2_journal_force_commit(journal_t *);
extern int	   jbd2_journal_force_commit_nested(journal_t *);
extern int	   jbd2_journal_inode_ranged_write(handle_t *handle,
			struct jbd2_inode *inode, loff_t start_byte,
			loff_t length);
extern int	   jbd2_journal_inode_ranged_wait(handle_t *handle,
			struct jbd2_inode *inode, loff_t start_byte,
			loff_t length);
extern int	   jbd2_journal_finish_inode_data_buffers(
			struct jbd2_inode *jinode);
extern int	   jbd2_journal_begin_ordered_truncate(journal_t *journal,
				struct jbd2_inode *inode, loff_t new_size);
extern void	   jbd2_journal_init_jbd_inode(struct jbd2_inode *jinode, struct inode *inode);
extern void	   jbd2_journal_release_jbd_inode(journal_t *journal, struct jbd2_inode *jinode);

/*
 * journal_head management
 */
struct journal_head *jbd2_journal_add_journal_head(struct buffer_head *bh);
struct journal_head *jbd2_journal_grab_journal_head(struct buffer_head *bh);
void jbd2_journal_put_journal_head(struct journal_head *jh);

/*
 * handle management
 */
extern struct kmem_cache *jbd2_handle_cache;

static inline handle_t *jbd2_alloc_handle(gfp_t gfp_flags)
{
	return kmem_cache_zalloc(jbd2_handle_cache, gfp_flags);
}

static inline void jbd2_free_handle(handle_t *handle)
{
	kmem_cache_free(jbd2_handle_cache, handle);
}

/*
 * jbd2_inode management (optional, for those file systems that want to use
 * dynamically allocated jbd2_inode structures)
 */
extern struct kmem_cache *jbd2_inode_cache;

static inline struct jbd2_inode *jbd2_alloc_inode(gfp_t gfp_flags)
{
	return kmem_cache_alloc(jbd2_inode_cache, gfp_flags);
}

static inline void jbd2_free_inode(struct jbd2_inode *jinode)
{
	kmem_cache_free(jbd2_inode_cache, jinode);
}

/* Primary revoke support */
#define JOURNAL_REVOKE_DEFAULT_HASH 256
extern int	   jbd2_journal_init_revoke(journal_t *, int);
extern void	   jbd2_journal_destroy_revoke_record_cache(void);
extern void	   jbd2_journal_destroy_revoke_table_cache(void);
extern int __init jbd2_journal_init_revoke_record_cache(void);
extern int __init jbd2_journal_init_revoke_table_cache(void);

extern void	   jbd2_journal_destroy_revoke(journal_t *);
extern int	   jbd2_journal_revoke (handle_t *, unsigned long long, struct buffer_head *);
extern int	   jbd2_journal_cancel_revoke(handle_t *, struct journal_head *);
extern void	   jbd2_journal_write_revoke_records(transaction_t *transaction,
						     struct list_head *log_bufs);

/* Recovery revoke support */
extern int	jbd2_journal_set_revoke(journal_t *, unsigned long long, tid_t);
extern int	jbd2_journal_test_revoke(journal_t *, unsigned long long, tid_t);
extern void	jbd2_journal_clear_revoke(journal_t *);
extern void	jbd2_journal_switch_revoke_table(journal_t *journal);
extern void	jbd2_clear_buffer_revoked_flags(journal_t *journal);

/*
 * The log thread user interface:
 *
 * Request space in the current transaction, and force transaction commit
 * transitions on demand.
 */

int jbd2_log_start_commit(journal_t *journal, tid_t tid);
int jbd2_journal_start_commit(journal_t *journal, tid_t *tid);
int jbd2_log_wait_commit(journal_t *journal, tid_t tid);
int jbd2_transaction_committed(journal_t *journal, tid_t tid);
int jbd2_complete_transaction(journal_t *journal, tid_t tid);
int jbd2_log_do_checkpoint(journal_t *journal);
int jbd2_trans_will_send_data_barrier(journal_t *journal, tid_t tid);

void __jbd2_log_wait_for_space(journal_t *journal);
extern void __jbd2_journal_drop_transaction(journal_t *, transaction_t *);
extern int jbd2_cleanup_journal_tail(journal_t *);

/* Fast commit related APIs */
int jbd2_fc_begin_commit(journal_t *journal, tid_t tid);
int jbd2_fc_end_commit(journal_t *journal);
int jbd2_fc_end_commit_fallback(journal_t *journal);
int jbd2_fc_get_buf(journal_t *journal, struct buffer_head **bh_out);
int jbd2_submit_inode_data(journal_t *journal, struct jbd2_inode *jinode);
int jbd2_wait_inode_data(journal_t *journal, struct jbd2_inode *jinode);
int jbd2_fc_wait_bufs(journal_t *journal, int num_blks);
int jbd2_fc_release_bufs(journal_t *journal);

/*
 * is_journal_abort
 *
 * Simple test wrapper function to test the JBD2_ABORT state flag.  This
 * bit, when set, indicates that we have had a fatal error somewhere,
 * either inside the journaling layer or indicated to us by the client
 * (eg. ext3), and that we and should not commit any further
 * transactions.
 */

static inline int is_journal_aborted(journal_t *journal)
{
	return journal->j_flags & JBD2_ABORT;
}

static inline int is_handle_aborted(handle_t *handle)
{
	if (handle->h_aborted || !handle->h_transaction)
		return 1;
	return is_journal_aborted(handle->h_transaction->t_journal);
}

static inline void jbd2_journal_abort_handle(handle_t *handle)
{
	handle->h_aborted = 1;
}

static inline void jbd2_init_fs_dev_write_error(journal_t *journal)
{
	struct address_space *mapping = journal->j_fs_dev->bd_inode->i_mapping;

	/*
	 * Save the original wb_err value of client fs's bdev mapping which
	 * could be used to detect the client fs's metadata async write error.
	 */
	errseq_check_and_advance(&mapping->wb_err, &journal->j_fs_dev_wb_err);
}

static inline int jbd2_check_fs_dev_write_error(journal_t *journal)
{
	struct address_space *mapping = journal->j_fs_dev->bd_inode->i_mapping;

	return errseq_check(&mapping->wb_err,
			    READ_ONCE(journal->j_fs_dev_wb_err));
}

#endif /* __KERNEL__   */

/* Comparison functions for transaction IDs: perform comparisons using
 * modulo arithmetic so that they work over sequence number wraps. */

static inline int tid_gt(tid_t x, tid_t y)
{
	int difference = (x - y);
	return (difference > 0);
}

static inline int tid_geq(tid_t x, tid_t y)
{
	int difference = (x - y);
	return (difference >= 0);
}

extern int jbd2_journal_blocks_per_page(struct inode *inode);
extern size_t journal_tag_bytes(journal_t *journal);

static inline bool jbd2_journal_has_csum_v2or3_feature(journal_t *j)
{
	return jbd2_has_feature_csum2(j) || jbd2_has_feature_csum3(j);
}

static inline int jbd2_journal_has_csum_v2or3(journal_t *journal)
{
	WARN_ON_ONCE(jbd2_journal_has_csum_v2or3_feature(journal) &&
		     journal->j_chksum_driver == NULL);

	return journal->j_chksum_driver != NULL;
}

static inline int jbd2_journal_get_num_fc_blks(journal_superblock_t *jsb)
{
	int num_fc_blocks = be32_to_cpu(jsb->s_num_fc_blks);

	return num_fc_blocks ? num_fc_blocks : JBD2_DEFAULT_FAST_COMMIT_BLOCKS;
}

/*
 * Return number of free blocks in the log. Must be called under j_state_lock.
 */
static inline unsigned long jbd2_log_space_left(journal_t *journal)
{
	/* Allow for rounding errors */
	long free = journal->j_free - 32;

	if (journal->j_committing_transaction) {
		free -= atomic_read(&journal->
                        j_committing_transaction->t_outstanding_credits);
	}
	return max_t(long, free, 0);
}

/*
 * Definitions which augment the buffer_head layer
 */

/* journaling buffer types */
#define BJ_None		0	/* Not journaled */
#define BJ_Metadata	1	/* Normal journaled metadata */
#define BJ_Forget	2	/* Buffer superseded by this transaction */
#define BJ_Shadow	3	/* Buffer contents being shadowed to the log */
#define BJ_Reserved	4	/* Buffer is reserved for access by journal */
#define BJ_Types	5

/* JBD uses a CRC32 checksum */
#define JBD_MAX_CHECKSUM_SIZE 4

static inline u32 jbd2_chksum(journal_t *journal, u32 crc,
			      const void *address, unsigned int length)
{
	struct {
		struct shash_desc shash;
		char ctx[JBD_MAX_CHECKSUM_SIZE];
	} desc;
	int err;

	BUG_ON(crypto_shash_descsize(journal->j_chksum_driver) >
		JBD_MAX_CHECKSUM_SIZE);

	desc.shash.tfm = journal->j_chksum_driver;
	*(u32 *)desc.ctx = crc;

	err = crypto_shash_update(&desc.shash, address, length);
	BUG_ON(err);

	return *(u32 *)desc.ctx;
}

/* Return most recent uncommitted transaction */
static inline tid_t  jbd2_get_latest_transaction(journal_t *journal)
{
	tid_t tid;

	read_lock(&journal->j_state_lock);
	tid = journal->j_commit_request;
	if (journal->j_running_transaction)
		tid = journal->j_running_transaction->t_tid;
	read_unlock(&journal->j_state_lock);
	return tid;
}

static inline int jbd2_handle_buffer_credits(handle_t *handle)
{
	journal_t *journal;

	if (!handle->h_reserved)
		journal = handle->h_transaction->t_journal;
	else
		journal = handle->h_journal;

	return handle->h_total_credits -
		DIV_ROUND_UP(handle->h_revoke_credits_requested,
			     journal->j_revoke_records_per_block);
}

#ifdef __KERNEL__

#define buffer_trace_init(bh)	do {} while (0)
#define print_buffer_fields(bh)	do {} while (0)
#define print_buffer_trace(bh)	do {} while (0)
#define BUFFER_TRACE(bh, info)	do {} while (0)
#define BUFFER_TRACE2(bh, bh2, info)	do {} while (0)
#define JBUFFER_TRACE(jh, info)	do {} while (0)

#endif	/* __KERNEL__ */

#define EFSBADCRC	EBADMSG		/* Bad CRC detected */
#define EFSCORRUPTED	EUCLEAN		/* Filesystem is corrupted */

#endif	/* _LINUX_JBD2_H */
¿Qué es la limpieza dental de perros? - Clínica veterinaria


Es la eliminación del sarro y la placa adherida a la superficie de los dientes mediante un equipo de ultrasonidos que garantiza la integridad de las piezas dentales a la vez que elimina en profundidad cualquier resto de suciedad.

A continuación se procede al pulido de los dientes mediante una fresa especial que elimina la placa bacteriana y devuelve a los dientes el aspecto sano que deben tener.

Una vez terminado todo el proceso, se mantiene al perro en observación hasta que se despierta de la anestesia, bajo la atenta supervisión de un veterinario.

¿Cada cuánto tiempo tengo que hacerle una limpieza dental a mi perro?

A partir de cierta edad, los perros pueden necesitar una limpieza dental anual o bianual. Depende de cada caso. En líneas generales, puede decirse que los perros de razas pequeñas suelen acumular más sarro y suelen necesitar una atención mayor en cuanto a higiene dental.


Riesgos de una mala higiene


Los riesgos más evidentes de una mala higiene dental en los perros son los siguientes:

  • Cuando la acumulación de sarro no se trata, se puede producir una inflamación y retracción de las encías que puede descalzar el diente y provocar caídas.
  • Mal aliento (halitosis).
  • Sarro perros
  • Puede ir a más
  • Las bacterias de la placa pueden trasladarse a través del torrente circulatorio a órganos vitales como el corazón ocasionando problemas de endocarditis en las válvulas. Las bacterias pueden incluso acantonarse en huesos (La osteomielitis es la infección ósea, tanto cortical como medular) provocando mucho dolor y una artritis séptica).

¿Cómo se forma el sarro?

El sarro es la calcificación de la placa dental. Los restos de alimentos, junto con las bacterias presentes en la boca, van a formar la placa bacteriana o placa dental. Si la placa no se retira, al mezclarse con la saliva y los minerales presentes en ella, reaccionará formando una costra. La placa se calcifica y se forma el sarro.

El sarro, cuando se forma, es de color blanquecino pero a medida que pasa el tiempo se va poniendo amarillo y luego marrón.

Síntomas de una pobre higiene dental
La señal más obvia de una mala salud dental canina es el mal aliento.

Sin embargo, a veces no es tan fácil de detectar
Y hay perros que no se dejan abrir la boca por su dueño. Por ejemplo…

Recientemente nos trajeron a la clínica a un perro que parpadeaba de un ojo y decía su dueño que le picaba un lado de la cara. Tenía molestias y dificultad para comer, lo que había llevado a sus dueños a comprarle comida blanda (que suele ser un poco más cara y llevar más contenido en grasa) durante medio año. Después de una exploración oftalmológica, nos dimos cuenta de que el ojo tenía una úlcera en la córnea probablemente de rascarse . Además, el canto lateral del ojo estaba inflamado. Tenía lo que en humanos llamamos flemón pero como era un perro de pelo largo, no se le notaba a simple vista. Al abrirle la boca nos llamó la atención el ver una muela llena de sarro. Le realizamos una radiografía y encontramos una fístula que llegaba hasta la parte inferior del ojo.

Le tuvimos que extraer la muela. Tras esto, el ojo se curó completamente con unos colirios y una lentilla protectora de úlcera. Afortunadamente, la úlcera no profundizó y no perforó el ojo. Ahora el perro come perfectamente a pesar de haber perdido una muela.

¿Cómo mantener la higiene dental de tu perro?
Hay varias maneras de prevenir problemas derivados de la salud dental de tu perro.

Limpiezas de dientes en casa
Es recomendable limpiar los dientes de tu perro semanal o diariamente si se puede. Existe una gran variedad de productos que se pueden utilizar:

Pastas de dientes.
Cepillos de dientes o dedales para el dedo índice, que hacen más fácil la limpieza.
Colutorios para echar en agua de bebida o directamente sobre el diente en líquido o en spray.

En la Clínica Tus Veterinarios enseñamos a nuestros clientes a tomar el hábito de limpiar los dientes de sus perros desde que son cachorros. Esto responde a nuestro compromiso con la prevención de enfermedades caninas.

Hoy en día tenemos muchos clientes que limpian los dientes todos los días a su mascota, y como resultado, se ahorran el dinero de hacer limpiezas dentales profesionales y consiguen una mejor salud de su perro.


Limpiezas dentales profesionales de perros y gatos

Recomendamos hacer una limpieza dental especializada anualmente. La realizamos con un aparato de ultrasonidos que utiliza agua para quitar el sarro. Después, procedemos a pulir los dientes con un cepillo de alta velocidad y una pasta especial. Hacemos esto para proteger el esmalte.

La frecuencia de limpiezas dentales necesaria varía mucho entre razas. En general, las razas grandes tienen buena calidad de esmalte, por lo que no necesitan hacerlo tan a menudo e incluso pueden pasarse la vida sin requerir una limpieza. Sin embargo, razas pequeñas como el Yorkshire o el Maltés, deben hacérselas todos los años desde cachorros si se quiere conservar sus piezas dentales.

Otro factor fundamental es la calidad del pienso. Algunas marcas han diseñado croquetas que limpian la superficie del diente y de la muela al masticarse.

Ultrasonido para perros

¿Se necesita anestesia para las limpiezas dentales de perros y gatos?

La limpieza dental en perros no es una técnica que pueda practicarse sin anestesia general , aunque hay veces que los propietarios no quieren anestesiar y si tiene poco sarro y el perro es muy bueno se puede intentar…… , pero no se va a poder pulir ni acceder a todas la zona de la boca …. Además los limpiadores dentales van a irrigar agua y hay riesgo de aspiración a vías respiratorias si no se realiza una anestesia correcta con intubación traqueal . En resumen , sin anestesia no se va hacer una correcta limpieza dental.

Tampoco sirve la sedación ya que necesitamos que el animal esté totalmente quieto, y el veterinario tenga un acceso completo a todas sus piezas dentales y encías.

Alimentos para la limpieza dental

Hay que tener cierto cuidado a la hora de comprar determinados alimentos porque no todos son saludables. Algunos tienen demasiado contenido graso, que en exceso puede causar problemas cardiovasculares y obesidad.

Los mejores alimentos para los dientes son aquellos que están elaborados por empresas farmacéuticas y llevan componentes químicos con tratamientos específicos para el diente del perro. Esto implica no solo limpieza a través de la acción mecánica de morder sino también un tratamiento antibacteriano para prevenir el sarro.

Conclusión

Si eres como la mayoría de dueños, por falta de tiempo , es probable que no estés prestando la suficiente atención a la limpieza dental de tu perro. Por eso te animamos a que comiences a limpiar los dientes de tu perro y consideres atender a su higiene bucal con frecuencia.

Estas simples medidas pueden conllevar a que tu perro tenga una vida más larga y mucho más saludable.

Si te resulta imposible introducir un cepillo de dientes a tu perro en la boca, pásate con él por clínica Tus Veterinarios y te explicamos cómo hacerlo.

Necesitas hacer una limpieza dental profesional a tu mascota?
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