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linux-next/include/linux/jbd2.h
Theodore Ts'o cc3e1bea5d ext4, jbd2: Add barriers for file systems with exernal journals 
This is a bit complicated because we are trying to optimize when we
send barriers to the fs data disk.  We could just throw in an extra
barrier to the data disk whenever we send a barrier to the journal
disk, but that's not always strictly necessary.

We only need to send a barrier during a commit when there are data
blocks which are must be written out due to an inode written in
ordered mode, or if fsync() depends on the commit to force data blocks
to disk.  Finally, before we drop transactions from the beginning of
the journal during a checkpoint operation, we need to guarantee that
any blocks that were flushed out to the data disk are firmly on the
rust platter before we drop the transaction from the journal.

Thanks to Oleg Drokin for pointing out this flaw in ext3/ext4.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2009-12-23 06:52:08 -05:00

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/*
* linux/include/linux/jbd2.h
*
* Written by Stephen C. Tweedie <sct@redhat.com>
*
* Copyright 1998-2000 Red Hat, Inc --- All Rights Reserved
*
* This file is part of the Linux kernel and is made available under
* the terms of the GNU General Public License, version 2, or at your
* option, any later version, incorporated herein by reference.
*
* 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
#define jfs_debug jbd_debug
#else
#include <linux/types.h>
#include <linux/buffer_head.h>
#include <linux/journal-head.h>
#include <linux/stddef.h>
#include <linux/bit_spinlock.h>
#include <linux/mutex.h>
#include <linux/timer.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
extern u8 jbd2_journal_enable_debug;
#define jbd_debug(n, f, a...) \
do { \
if ((n) <= jbd2_journal_enable_debug) { \
printk (KERN_DEBUG "(%s, %d): %s: ", \
__FILE__, __LINE__, __func__); \
printk (f, ## a); \
} \
} while (0)
#else
#define jbd_debug(f, a...) /**/
#endif
static inline void *jbd2_alloc(size_t size, gfp_t flags)
{
return (void *)__get_free_pages(flags, get_order(size));
}
static inline void jbd2_free(void *ptr, size_t size)
{
free_pages((unsigned long)ptr, get_order(size));
};
#define JBD2_MIN_JOURNAL_BLOCKS 1024
#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 handle_s 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_CRC32_CHKSUM_SIZE 4
#define JBD2_CHECKSUM_BYTES (32 / sizeof(u32))
/*
* Commit block header for storing transactional checksums:
*/
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_tag_s
{
__be32 t_blocknr; /* The on-disk block number */
__be32 t_flags; /* See below */
__be32 t_blocknr_high; /* most-significant high 32bits. */
} journal_block_tag_t;
#define JBD2_TAG_SIZE32 (offsetof(journal_block_tag_t, t_blocknr_high))
#define JBD2_TAG_SIZE64 (sizeof(journal_block_tag_t))
/*
* 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 */
__u32 s_padding[44];
/* 0x0100 */
__u8 s_users[16*48]; /* ids of all fs'es sharing the log */
/* 0x0400 */
} journal_superblock_t;
#define JBD2_HAS_COMPAT_FEATURE(j,mask) \
((j)->j_format_version >= 2 && \
((j)->j_superblock->s_feature_compat & cpu_to_be32((mask))))
#define JBD2_HAS_RO_COMPAT_FEATURE(j,mask) \
((j)->j_format_version >= 2 && \
((j)->j_superblock->s_feature_ro_compat & cpu_to_be32((mask))))
#define JBD2_HAS_INCOMPAT_FEATURE(j,mask) \
((j)->j_format_version >= 2 && \
((j)->j_superblock->s_feature_incompat & cpu_to_be32((mask))))
#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
/* 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)
#ifdef __KERNEL__
#include <linux/fs.h>
#include <linux/sched.h>
#define J_ASSERT(assert) BUG_ON(!(assert))
#if defined(CONFIG_BUFFER_DEBUG)
void buffer_assertion_failure(struct buffer_head *bh);
#define J_ASSERT_BH(bh, expr) \
do { \
if (!(expr)) \
buffer_assertion_failure(bh); \
J_ASSERT(expr); \
} while (0)
#define J_ASSERT_JH(jh, expr) J_ASSERT_BH(jh2bh(jh), expr)
#else
#define J_ASSERT_BH(bh, expr) J_ASSERT(expr)
#define J_ASSERT_JH(jh, expr) J_ASSERT(expr)
#endif
#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
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_State, /* Pins most journal_head state */
BH_JournalHead, /* Pins bh->b_private and jh->b_bh */
BH_Unshadow, /* Dummy bit, for BJ_Shadow wakeup filtering */
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)
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_state(struct buffer_head *bh)
{
bit_spin_lock(BH_State, &bh->b_state);
}
static inline int jbd_trylock_bh_state(struct buffer_head *bh)
{
return bit_spin_trylock(BH_State, &bh->b_state);
}
static inline int jbd_is_locked_bh_state(struct buffer_head *bh)
{
return bit_spin_is_locked(BH_State, &bh->b_state);
}
static inline void jbd_unlock_bh_state(struct buffer_head *bh)
{
bit_spin_unlock(BH_State, &bh->b_state);
}
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);
}
/* Flags in jbd_inode->i_flags */
#define __JI_COMMIT_RUNNING 0
/* 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)
/**
* struct jbd_inode is the structure linking inodes in ordered mode
* present in a transaction so that we can sync them during commit.
*/
struct jbd2_inode {
/* Which transaction does this inode belong to? Either the running
* transaction or the committing one. [j_list_lock] */
transaction_t *i_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;
/* List of inodes in the i_transaction [j_list_lock] */
struct list_head i_list;
/* VFS inode this inode belongs to [constant during the lifetime
* of the structure] */
struct inode *i_vfs_inode;
/* Flags of inode [j_list_lock] */
unsigned int i_flags;
};
struct jbd2_revoke_table_s;
/**
* struct handle_s - The handle_s type is the concrete type associated with
* handle_t.
* @h_transaction: Which compound transaction is this update a part of?
* @h_buffer_credits: Number of remaining buffers we are allowed to dirty.
* @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_aborted: flag indicating fatal error on handle
**/
/* Docbook can't yet cope with the bit fields, but will leave the documentation
* in so it can be fixed later.
*/
struct handle_s
{
/* Which compound transaction is this update a part of? */
transaction_t *h_transaction;
/* Number of remaining buffers we are allowed to dirty: */
int h_buffer_credits;
/* Reference count on this handle */
int h_ref;
/* Field for caller's use to track errors through large fs */
/* operations */
int h_err;
/* Flags [no locking] */
unsigned int h_sync: 1; /* sync-on-close */
unsigned int h_jdata: 1; /* force data journaling */
unsigned int h_aborted: 1; /* fatal error on handle */
#ifdef CONFIG_DEBUG_LOCK_ALLOC
struct lockdep_map h_lockdep_map;
#endif
};
/*
* 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.
*/
/*
* Lock ranking:
*
* j_list_lock
* ->jbd_lock_bh_journal_head() (This is "innermost")
*
* j_state_lock
* ->jbd_lock_bh_state()
*
* jbd_lock_bh_state()
* ->j_list_lock
*
* j_state_lock
* ->t_handle_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_RUNDOWN,
T_FLUSH,
T_COMMIT,
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] */
int t_nr_buffers;
/*
* Doubly-linked circular list of all buffers reserved but not yet
* modified by this transaction [j_list_lock]
*/
struct journal_head *t_reserved_list;
/*
* Doubly-linked circular list of all metadata buffers owned by this
* transaction [j_list_lock]
*/
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 all buffers submitted for IO while
* checkpointing. [j_list_lock]
*/
struct journal_head *t_checkpoint_io_list;
/*
* Doubly-linked circular list of temporary buffers currently undergoing
* IO in the log [j_list_lock]
*/
struct journal_head *t_iobuf_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]
*/
struct journal_head *t_shadow_list;
/*
* Doubly-linked circular list of control buffers being written to the
* log. [j_list_lock]
*/
struct journal_head *t_log_list;
/*
* List of inodes whose data we've modified in data=ordered mode.
* [j_list_lock]
*/
struct list_head t_inode_list;
/*
* Protects info related to handles
*/
spinlock_t t_handle_lock;
/*
* Longest time some handle had to wait for running transaction
*/
unsigned long t_max_wait;
/*
* When transaction started
*/
unsigned long t_start;
/*
* Checkpointing stats [j_checkpoint_sem]
*/
struct transaction_chp_stats_s t_chp_stats;
/*
* Number of outstanding updates running on this transaction
* [t_handle_lock]
*/
int t_updates;
/*
* Number of buffers reserved for use by all handles in this transaction
* handle but not yet modified. [t_handle_lock]
*/
int t_outstanding_credits;
/*
* 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;
/*
* How many handles used this transaction? [t_handle_lock]
*/
int t_handle_count;
/*
* This transaction is being forced and some process is
* waiting for it to finish.
*/
unsigned int t_synchronous_commit:1;
unsigned int t_flushed_data_blocks:1;
/*
* 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_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;
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
/**
* struct journal_s - The journal_s type is the concrete type associated with
* journal_t.
* @j_flags: General journaling state flags
* @j_errno: Is there an outstanding uncleared error on the journal (from a
* prior abort)?
* @j_sb_buffer: First part of superblock buffer
* @j_superblock: Second part of superblock buffer
* @j_format_version: Version of the superblock format
* @j_state_lock: Protect the various scalars in the journal
* @j_barrier_count: Number of processes waiting to create a barrier lock
* @j_barrier: The barrier lock itself
* @j_running_transaction: The current running transaction..
* @j_committing_transaction: the transaction we are pushing to disk
* @j_checkpoint_transactions: a linked circular list of all transactions
* waiting for checkpointing
* @j_wait_transaction_locked: Wait queue for waiting for a locked transaction
* to start committing, or for a barrier lock to be released
* @j_wait_logspace: Wait queue for waiting for checkpointing to complete
* @j_wait_done_commit: Wait queue for waiting for commit to complete
* @j_wait_checkpoint: Wait queue to trigger checkpointing
* @j_wait_commit: Wait queue to trigger commit
* @j_wait_updates: Wait queue to wait for updates to complete
* @j_checkpoint_mutex: Mutex for locking against concurrent checkpoints
* @j_head: Journal head - identifies the first unused block in the journal
* @j_tail: Journal tail - identifies the oldest still-used block in the
* journal.
* @j_free: Journal free - how many free blocks are there in the journal?
* @j_first: The block number of the first usable block
* @j_last: The block number one beyond the last usable block
* @j_dev: Device where we store the journal
* @j_blocksize: blocksize for the location where we store the journal.
* @j_blk_offset: starting block offset for into the device where we store the
* journal
* @j_fs_dev: Device which holds the client fs. For internal journal this will
* be equal to j_dev
* @j_maxlen: Total maximum capacity of the journal region on disk.
* @j_list_lock: Protects the buffer lists and internal buffer state.
* @j_inode: Optional inode where we store the journal. If present, all journal
* block numbers are mapped into this inode via bmap().
* @j_tail_sequence: Sequence number of the oldest transaction in the log
* @j_transaction_sequence: Sequence number of the next transaction to grant
* @j_commit_sequence: Sequence number of the most recently committed
* transaction
* @j_commit_request: Sequence number of the most recent transaction wanting
* commit
* @j_uuid: Uuid of client object.
* @j_task: Pointer to the current commit thread for this journal
* @j_max_transaction_buffers: Maximum number of metadata buffers to allow in a
* single compound commit transaction
* @j_commit_interval: What is the maximum transaction lifetime before we begin
* a commit?
* @j_commit_timer: The timer used to wakeup the commit thread
* @j_revoke_lock: Protect the revoke table
* @j_revoke: The revoke table - maintains the list of revoked blocks in the
* current transaction.
* @j_revoke_table: alternate revoke tables for j_revoke
* @j_wbuf: array of buffer_heads for jbd2_journal_commit_transaction
* @j_wbufsize: maximum number of buffer_heads allowed in j_wbuf, the
* number that will fit in j_blocksize
* @j_last_sync_writer: most recent pid which did a synchronous write
* @j_history: Buffer storing the transactions statistics history
* @j_history_max: Maximum number of transactions in the statistics history
* @j_history_cur: Current number of transactions in the statistics history
* @j_history_lock: Protect the transactions statistics history
* @j_proc_entry: procfs entry for the jbd statistics directory
* @j_stats: Overall statistics
* @j_private: An opaque pointer to fs-private information.
*/
struct journal_s
{
/* General journaling state flags [j_state_lock] */
unsigned long j_flags;
/*
* Is there an outstanding uncleared error on the journal (from a prior
* abort)? [j_state_lock]
*/
int j_errno;
/* The superblock buffer */
struct buffer_head *j_sb_buffer;
journal_superblock_t *j_superblock;
/* Version of the superblock format */
int j_format_version;
/*
* Protect the various scalars in the journal
*/
spinlock_t j_state_lock;
/*
* Number of processes waiting to create a barrier lock [j_state_lock]
*/
int j_barrier_count;
/* The barrier lock itself */
struct mutex j_barrier;
/*
* Transactions: The current running transaction...
* [j_state_lock] [caller holding open handle]
*/
transaction_t *j_running_transaction;
/*
* the transaction we are pushing to disk
* [j_state_lock] [caller holding open handle]
*/
transaction_t *j_committing_transaction;
/*
* ... and a linked circular list of all transactions waiting for
* checkpointing. [j_list_lock]
*/
transaction_t *j_checkpoint_transactions;
/*
* 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;
/* Wait queue for waiting for checkpointing to complete */
wait_queue_head_t j_wait_logspace;
/* Wait queue for waiting for commit to complete */
wait_queue_head_t j_wait_done_commit;
/* Wait queue to trigger checkpointing */
wait_queue_head_t j_wait_checkpoint;
/* Wait queue to trigger commit */
wait_queue_head_t j_wait_commit;
/* Wait queue to wait for updates to complete */
wait_queue_head_t j_wait_updates;
/* Semaphore for locking against concurrent checkpoints */
struct mutex j_checkpoint_mutex;
/*
* 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];
/*
* Journal head: identifies the first unused block in the journal.
* [j_state_lock]
*/
unsigned long j_head;
/*
* Journal tail: identifies the oldest still-used block in the journal.
* [j_state_lock]
*/
unsigned long j_tail;
/*
* Journal free: how many free blocks are there in the journal?
* [j_state_lock]
*/
unsigned long j_free;
/*
* Journal start and end: the block numbers of the first usable block
* and one beyond the last usable block in the journal. [j_state_lock]
*/
unsigned long j_first;
unsigned long j_last;
/*
* Device, blocksize and starting block offset for the location where we
* store the journal.
*/
struct block_device *j_dev;
int j_blocksize;
unsigned long long j_blk_offset;
char j_devname[BDEVNAME_SIZE+24];
/*
* Device which holds the client fs. For internal journal this will be
* equal to j_dev.
*/
struct block_device *j_fs_dev;
/* Total maximum capacity of the journal region on disk. */
unsigned int j_maxlen;
/*
* Protects the buffer lists and internal buffer state.
*/
spinlock_t j_list_lock;
/* Optional inode where we store the journal. If present, all */
/* journal block numbers are mapped into this inode via */
/* bmap(). */
struct inode *j_inode;
/*
* Sequence number of the oldest transaction in the log [j_state_lock]
*/
tid_t j_tail_sequence;
/*
* Sequence number of the next transaction to grant [j_state_lock]
*/
tid_t j_transaction_sequence;
/*
* Sequence number of the most recently committed transaction
* [j_state_lock].
*/
tid_t j_commit_sequence;
/*
* Sequence number of the most recent transaction wanting commit
* [j_state_lock]
*/
tid_t j_commit_request;
/*
* 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];
/* Pointer to the current commit thread for this journal */
struct task_struct *j_task;
/*
* Maximum number of metadata buffers to allow in a single compound
* commit transaction
*/
int j_max_transaction_buffers;
/*
* What is the maximum transaction lifetime before we begin a commit?
*/
unsigned long j_commit_interval;
/* The timer used to wakeup the commit thread: */
struct timer_list j_commit_timer;
/*
* The revoke table: maintains the list of revoked blocks in the
* current transaction. [j_revoke_lock]
*/
spinlock_t j_revoke_lock;
struct jbd2_revoke_table_s *j_revoke;
struct jbd2_revoke_table_s *j_revoke_table[2];
/*
* array of bhs for jbd2_journal_commit_transaction
*/
struct buffer_head **j_wbuf;
int j_wbufsize;
/*
* this is the pid of hte last person to run a synchronous operation
* through the journal
*/
pid_t j_last_sync_writer;
/*
* the average amount of time in nanoseconds it takes to commit a
* transaction to disk. [j_state_lock]
*/
u64 j_average_commit_time;
/*
* minimum and maximum times that we should wait for
* additional filesystem operations to get batched into a
* synchronous handle in microseconds
*/
u32 j_min_batch_time;
u32 j_max_batch_time;
/* This function is called when a transaction is closed */
void (*j_commit_callback)(journal_t *,
transaction_t *);
/*
* Journal statistics
*/
spinlock_t j_history_lock;
struct proc_dir_entry *j_proc_entry;
struct transaction_stats_s j_stats;
/* Failed journal commit ID */
unsigned int j_failed_commit;
/*
* An opaque pointer to fs-private information. ext3 puts its
* superblock pointer here
*/
void *j_private;
};
/*
* 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 */
/*
* Function declarations for the journaling transaction and buffer
* management
*/
/* Filing buffers */
extern void jbd2_journal_unfile_buffer(journal_t *, struct journal_head *);
extern void __jbd2_journal_unfile_buffer(struct journal_head *);
extern void __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 __journal_free_buffer(struct journal_head *bh);
extern void jbd2_journal_file_buffer(struct journal_head *, transaction_t *, int);
extern void __journal_clean_data_list(transaction_t *transaction);
/* Log buffer allocation */
extern struct journal_head * jbd2_journal_get_descriptor_buffer(journal_t *);
int jbd2_journal_next_log_block(journal_t *, unsigned long long *);
/* Commit management */
extern void jbd2_journal_commit_transaction(journal_t *);
/* Checkpoint list management */
int __jbd2_journal_clean_checkpoint_list(journal_t *journal);
int __jbd2_journal_remove_checkpoint(struct journal_head *);
void __jbd2_journal_insert_checkpoint(struct journal_head *, transaction_t *);
/*
* Triggers
*/
struct jbd2_buffer_trigger_type {
/*
* Fired just before a buffer is written to the journal.
* mapped_data is a mapped buffer that is the frozen data for
* commit.
*/
void (*t_commit)(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_commit_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 journal_head **jh_out,
unsigned long long blocknr);
/* Transaction locking */
extern void __wait_on_journal (journal_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 int jbd2_journal_restart (handle_t *, int nblocks);
extern int jbd2_journal_extend (handle_t *, int nblocks);
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 void jbd2_journal_release_buffer (handle_t *, struct buffer_head *);
extern int jbd2_journal_forget (handle_t *, struct buffer_head *);
extern void journal_sync_buffer (struct buffer_head *);
extern void jbd2_journal_invalidatepage(journal_t *,
struct page *, unsigned long);
extern int jbd2_journal_try_to_free_buffers(journal_t *, struct page *, gfp_t);
extern int jbd2_journal_stop(handle_t *);
extern int jbd2_journal_flush (journal_t *);
extern void jbd2_journal_lock_updates (journal_t *);
extern void jbd2_journal_unlock_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_superblock (journal_t *, int);
extern void __jbd2_journal_abort_hard (journal_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_file_inode(handle_t *handle, struct jbd2_inode *inode);
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_remove_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_alloc(jbd2_handle_cache, gfp_flags);
}
static inline void jbd2_free_handle(handle_t *handle)
{
kmem_cache_free(jbd2_handle_cache, handle);
}
/* Primary revoke support */
#define JOURNAL_REVOKE_DEFAULT_HASH 256
extern int jbd2_journal_init_revoke(journal_t *, int);
extern void jbd2_journal_destroy_revoke_caches(void);
extern int jbd2_journal_init_revoke_caches(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(journal_t *,
transaction_t *, int);
/* 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);
/*
* The log thread user interface:
*
* Request space in the current transaction, and force transaction commit
* transitions on demand.
*/
int __jbd2_log_space_left(journal_t *); /* Called with journal locked */
int jbd2_log_start_commit(journal_t *journal, tid_t tid);
int __jbd2_log_start_commit(journal_t *journal, tid_t tid);
int jbd2_journal_start_commit(journal_t *journal, tid_t *tid);
int jbd2_journal_force_commit_nested(journal_t *journal);
int jbd2_log_wait_commit(journal_t *journal, tid_t tid);
int jbd2_log_do_checkpoint(journal_t *journal);
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 *);
/* Debugging code only: */
#define jbd_ENOSYS() \
do { \
printk (KERN_ERR "JBD unimplemented function %s\n", __func__); \
current->state = TASK_UNINTERRUPTIBLE; \
schedule(); \
} while (1)
/*
* 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)
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;
}
#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);
/*
* Return the minimum number of blocks which must be free in the journal
* before a new transaction may be started. Must be called under j_state_lock.
*/
static inline int jbd_space_needed(journal_t *journal)
{
int nblocks = journal->j_max_transaction_buffers;
if (journal->j_committing_transaction)
nblocks += journal->j_committing_transaction->
t_outstanding_credits;
return nblocks;
}
/*
* 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_IO 3 /* Buffer is for temporary IO use */
#define BJ_Shadow 4 /* Buffer contents being shadowed to the log */
#define BJ_LogCtl 5 /* Buffer contains log descriptors */
#define BJ_Reserved 6 /* Buffer is reserved for access by journal */
#define BJ_Types 7
extern int jbd_blocks_per_page(struct inode *inode);
#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)
/*
* jbd2_dev_to_name is a utility function used by the jbd2 and ext4
* tracing infrastructure to map a dev_t to a device name.
*/
extern const char *jbd2_dev_to_name(dev_t device);
#endif /* __KERNEL__ */
#endif /* _LINUX_JBD2_H */
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