--- /dev/null
+/*
+ * 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_JBD_H
+#define _LINUX_JBD_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>
+
+#include <asm/semaphore.h>
+#endif
+
+#define journal_oom_retry 1
+
+/*
+ * Define JBD_PARANIOD_IOFAIL to cause a kernel BUG() if ext3 finds
+ * certain classes of error which can occur due to failed IOs. Under
+ * normal use we want ext3 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 JBD_PARANOID_IOFAIL
+
+/*
+ * The default maximum commit age, in seconds.
+ */
+#define JBD_DEFAULT_MAX_COMMIT_AGE 5
+
+#ifdef CONFIG_JBD_DEBUG
+/*
+ * Define JBD_EXPENSIVE_CHECKING to enable more expensive internal
+ * consistency checks. By default we don't do this unless
+ * CONFIG_JBD_DEBUG is on.
+ */
+#define JBD_EXPENSIVE_CHECKING
+extern int 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__, __FUNCTION__); \
+ printk (f, ## a); \
+ } \
+ } while (0)
+#else
+#define jbd_debug(f, a...) /**/
+#endif
+
+extern void * __jbd2_kmalloc (const char *where, size_t size, gfp_t flags, int retry);
+extern void * jbd2_slab_alloc(size_t size, gfp_t flags);
+extern void jbd2_slab_free(void *ptr, size_t size);
+
+#define jbd_kmalloc(size, flags) \
+ __jbd2_kmalloc(__FUNCTION__, (size), (flags), journal_oom_retry)
+#define jbd_rep_kmalloc(size, flags) \
+ __jbd2_kmalloc(__FUNCTION__, (size), (flags), 1)
+
+#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;
+
+
+/*
+ * 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 JBD_TAG_SIZE32 (offsetof(journal_block_tag_t, t_blocknr_high))
+#define JBD_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_INCOMPAT_REVOKE 0x00000001
+#define JBD2_FEATURE_INCOMPAT_64BIT 0x00000002
+
+/* Features known to this kernel version: */
+#define JBD2_KNOWN_COMPAT_FEATURES 0
+#define JBD2_KNOWN_ROCOMPAT_FEATURES 0
+#define JBD2_KNOWN_INCOMPAT_FEATURES (JBD2_FEATURE_INCOMPAT_REVOKE | \
+ JBD2_FEATURE_INCOMPAT_64BIT)
+
+#ifdef __KERNEL__
+
+#include <linux/fs.h>
+#include <linux/sched.h>
+
+#define JBD_ASSERTIONS
+#ifdef JBD_ASSERTIONS
+#define J_ASSERT(assert) \
+do { \
+ if (!(assert)) { \
+ printk (KERN_EMERG \
+ "Assertion failure in %s() at %s:%d: \"%s\"\n", \
+ __FUNCTION__, __FILE__, __LINE__, # assert); \
+ BUG(); \
+ } \
+} while (0)
+
+#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
+
+#else
+#define J_ASSERT(assert) do { } while (0)
+#endif /* JBD_ASSERTIONS */
+
+#if defined(JBD_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 \
+ "EXT3-fs unexpected failure: %s;\n",# 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 */
+};
+
+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);
+}
+
+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 */
+};
+
+
+/* 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]
+ * 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 buffers under writeout during
+ * commit [j_list_lock]
+ */
+ struct journal_head *t_locked_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 data buffers still to be
+ * flushed before this transaction can be committed [j_list_lock]
+ */
+ struct journal_head *t_sync_datalist;
+
+ /*
+ * 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;
+
+ /*
+ * Protects info related to handles
+ */
+ spinlock_t t_handle_lock;
+
+ /*
+ * 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;
+
+ /*
+ * How many handles used this transaction? [t_handle_lock]
+ */
+ int t_handle_count;
+
+};
+
+/**
+ * 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_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;
+
+ /*
+ * 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;
+
+ /*
+ * 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;
+
+ pid_t j_last_sync_writer;
+
+ /*
+ * 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 */
+
+/*
+ * 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 *);
+
+/* 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 *);
+extern int jbd2_journal_dirty_data (handle_t *, struct buffer_head *);
+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 int jbd2_journal_create (journal_t *);
+extern int jbd2_journal_load (journal_t *journal);
+extern void 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 *);
+
+/*
+ * 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 *jbd_alloc_handle(gfp_t gfp_flags)
+{
+ return kmem_cache_alloc(jbd2_handle_cache, gfp_flags);
+}
+
+static inline void jbd_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 *);
+
+/* 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", __FUNCTION__); \
+ 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_SyncData 1 /* Normal data: flush before commit */
+#define BJ_Metadata 2 /* Normal journaled metadata */
+#define BJ_Forget 3 /* Buffer superseded by this transaction */
+#define BJ_IO 4 /* Buffer is for temporary IO use */
+#define BJ_Shadow 5 /* Buffer contents being shadowed to the log */
+#define BJ_LogCtl 6 /* Buffer contains log descriptors */
+#define BJ_Reserved 7 /* Buffer is reserved for access by journal */
+#define BJ_Locked 8 /* Locked for I/O during commit */
+#define BJ_Types 9
+
+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)
+
+#endif /* __KERNEL__ */
+
+#endif /* _LINUX_JBD_H */
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