journal.c

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/*
** Write ahead logging implementation copyright Chris Mason 2000
**
** The background commits make this code very interrelated, and
** overly complex.  I need to rethink things a bit....The major players:
**
** journal_begin -- call with the number of blocks you expect to log.
**                  If the current transaction is too
**          old, it will block until the current transaction is
**          finished, and then start a new one.
**          Usually, your transaction will get joined in with
**                  previous ones for speed.
**
** journal_join  -- same as journal_begin, but won't block on the current
**                  transaction regardless of age.  Don't ever call
**                  this.  Ever.  There are only two places it should be
**                  called from, and they are both inside this file.
**
** journal_mark_dirty -- adds blocks into this transaction.  clears any flags
**                       that might make them get sent to disk
**                       and then marks them BH_JDirty.  Puts the buffer head
**                       into the current transaction hash.
**
** journal_end -- if the current transaction is batchable, it does nothing
**                   otherwise, it could do an async/synchronous commit, or
**                   a full flush of all log and real blocks in the
**                   transaction.
**
** flush_old_commits -- if the current transaction is too old, it is ended and
**                      commit blocks are sent to disk.  Forces commit blocks
**                      to disk for all backgrounded commits that have been
**                      around too long.
**           -- Note, if you call this as an immediate flush from
**              from within kupdate, it will ignore the immediate flag
*/

#include <linux/time.h>
#include <linux/semaphore.h>
#include <linux/vmalloc.h>
#include "reiserfs.h"
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/fcntl.h>
#include <linux/stat.h>
#include <linux/string.h>
#include <linux/buffer_head.h>
#include <linux/workqueue.h>
#include <linux/writeback.h>
#include <linux/blkdev.h>
#include <linux/backing-dev.h>
#include <linux/uaccess.h>
#include <linux/slab.h>


/* gets a struct reiserfs_journal_list * from a list head */
#define JOURNAL_LIST_ENTRY(h) (list_entry((h), struct reiserfs_journal_list, \
                               j_list))
#define JOURNAL_WORK_ENTRY(h) (list_entry((h), struct reiserfs_journal_list, \
                               j_working_list))

/* the number of mounted filesystems.  This is used to decide when to
** start and kill the commit workqueue
*/
static int reiserfs_mounted_fs_count;

static struct workqueue_struct *commit_wq;

#define JOURNAL_TRANS_HALF 1018 /* must be correct to keep the desc and commit
                   structs at 4k */
#define BUFNR 64        /*read ahead */

/* cnode stat bits.  Move these into reiserfs_fs.h */

#define BLOCK_FREED 2       /* this block was freed, and can't be written.  */
#define BLOCK_FREED_HOLDER 3    /* this block was freed during this transaction, and can't be written */

#define BLOCK_NEEDS_FLUSH 4 /* used in flush_journal_list */
#define BLOCK_DIRTIED 5

/* journal list state bits */
#define LIST_TOUCHED 1
#define LIST_DIRTY   2
#define LIST_COMMIT_PENDING  4  /* someone will commit this list */

/* flags for do_journal_end */
#define FLUSH_ALL   1       /* flush commit and real blocks */
#define COMMIT_NOW  2       /* end and commit this transaction */
#define WAIT        4       /* wait for the log blocks to hit the disk */

static int do_journal_end(struct reiserfs_transaction_handle *,
              struct super_block *, unsigned long nblocks,
              int flags);
static int flush_journal_list(struct super_block *s,
                  struct reiserfs_journal_list *jl, int flushall);
static int flush_commit_list(struct super_block *s,
                 struct reiserfs_journal_list *jl, int flushall);
static int can_dirty(struct reiserfs_journal_cnode *cn);
static int journal_join(struct reiserfs_transaction_handle *th,
            struct super_block *sb, unsigned long nblocks);
static int release_journal_dev(struct super_block *super,
                   struct reiserfs_journal *journal);
static int dirty_one_transaction(struct super_block *s,
                 struct reiserfs_journal_list *jl);
static void flush_async_commits(struct work_struct *work);
static void queue_log_writer(struct super_block *s);

/* values for join in do_journal_begin_r */
enum {
    JBEGIN_REG = 0,     /* regular journal begin */
    JBEGIN_JOIN = 1,    /* join the running transaction if at all possible */
    JBEGIN_ABORT = 2,   /* called from cleanup code, ignores aborted flag */
};

static int do_journal_begin_r(struct reiserfs_transaction_handle *th,
                  struct super_block *sb,
                  unsigned long nblocks, int join);

static void init_journal_hash(struct super_block *sb)
{
    struct reiserfs_journal *journal = SB_JOURNAL(sb);
    memset(journal->j_hash_table, 0,
           JOURNAL_HASH_SIZE * sizeof(struct reiserfs_journal_cnode *));
}

/*
** clears BH_Dirty and sticks the buffer on the clean list.  Called because I can't allow refile_buffer to
** make schedule happen after I've freed a block.  Look at remove_from_transaction and journal_mark_freed for
** more details.
*/
static int reiserfs_clean_and_file_buffer(struct buffer_head *bh)
{
    if (bh) {
        clear_buffer_dirty(bh);
        clear_buffer_journal_test(bh);
    }
    return 0;
}

static struct reiserfs_bitmap_node *allocate_bitmap_node(struct super_block
                             *sb)
{
    struct reiserfs_bitmap_node *bn;
    static int id;

    bn = kmalloc(sizeof(struct reiserfs_bitmap_node), GFP_NOFS);
    if (!bn) {
        return NULL;
    }
    bn->data = kzalloc(sb->s_blocksize, GFP_NOFS);
    if (!bn->data) {
        kfree(bn);
        return NULL;
    }
    bn->id = id++;
    INIT_LIST_HEAD(&bn->list);
    return bn;
}

static struct reiserfs_bitmap_node *get_bitmap_node(struct super_block *sb)
{
    struct reiserfs_journal *journal = SB_JOURNAL(sb);
    struct reiserfs_bitmap_node *bn = NULL;
    struct list_head *entry = journal->j_bitmap_nodes.next;

    journal->j_used_bitmap_nodes++;
      repeat:

    if (entry != &journal->j_bitmap_nodes) {
        bn = list_entry(entry, struct reiserfs_bitmap_node, list);
        list_del(entry);
        memset(bn->data, 0, sb->s_blocksize);
        journal->j_free_bitmap_nodes--;
        return bn;
    }
    bn = allocate_bitmap_node(sb);
    if (!bn) {
        yield();
        goto repeat;
    }
    return bn;
}
static inline void free_bitmap_node(struct super_block *sb,
                    struct reiserfs_bitmap_node *bn)
{
    struct reiserfs_journal *journal = SB_JOURNAL(sb);
    journal->j_used_bitmap_nodes--;
    if (journal->j_free_bitmap_nodes > REISERFS_MAX_BITMAP_NODES) {
        kfree(bn->data);
        kfree(bn);
    } else {
        list_add(&bn->list, &journal->j_bitmap_nodes);
        journal->j_free_bitmap_nodes++;
    }
}

static void allocate_bitmap_nodes(struct super_block *sb)
{
    int i;
    struct reiserfs_journal *journal = SB_JOURNAL(sb);
    struct reiserfs_bitmap_node *bn = NULL;
    for (i = 0; i < REISERFS_MIN_BITMAP_NODES; i++) {
        bn = allocate_bitmap_node(sb);
        if (bn) {
            list_add(&bn->list, &journal->j_bitmap_nodes);
            journal->j_free_bitmap_nodes++;
        } else {
            break;  /* this is ok, we'll try again when more are needed */
        }
    }
}

static int set_bit_in_list_bitmap(struct super_block *sb,
                  b_blocknr_t block,
                  struct reiserfs_list_bitmap *jb)
{
    unsigned int bmap_nr = block / (sb->s_blocksize << 3);
    unsigned int bit_nr = block % (sb->s_blocksize << 3);

    if (!jb->bitmaps[bmap_nr]) {
        jb->bitmaps[bmap_nr] = get_bitmap_node(sb);
    }
    set_bit(bit_nr, (unsigned long *)jb->bitmaps[bmap_nr]->data);
    return 0;
}

static void cleanup_bitmap_list(struct super_block *sb,
                struct reiserfs_list_bitmap *jb)
{
    int i;
    if (jb->bitmaps == NULL)
        return;

    for (i = 0; i < reiserfs_bmap_count(sb); i++) {
        if (jb->bitmaps[i]) {
            free_bitmap_node(sb, jb->bitmaps[i]);
            jb->bitmaps[i] = NULL;
        }
    }
}

/*
** only call this on FS unmount.
*/
static int free_list_bitmaps(struct super_block *sb,
                 struct reiserfs_list_bitmap *jb_array)
{
    int i;
    struct reiserfs_list_bitmap *jb;
    for (i = 0; i < JOURNAL_NUM_BITMAPS; i++) {
        jb = jb_array + i;
        jb->journal_list = NULL;
        cleanup_bitmap_list(sb, jb);
        vfree(jb->bitmaps);
        jb->bitmaps = NULL;
    }
    return 0;
}

static int free_bitmap_nodes(struct super_block *sb)
{
    struct reiserfs_journal *journal = SB_JOURNAL(sb);
    struct list_head *next = journal->j_bitmap_nodes.next;
    struct reiserfs_bitmap_node *bn;

    while (next != &journal->j_bitmap_nodes) {
        bn = list_entry(next, struct reiserfs_bitmap_node, list);
        list_del(next);
        kfree(bn->data);
        kfree(bn);
        next = journal->j_bitmap_nodes.next;
        journal->j_free_bitmap_nodes--;
    }

    return 0;
}

/*
** get memory for JOURNAL_NUM_BITMAPS worth of bitmaps.
** jb_array is the array to be filled in.
*/
int reiserfs_allocate_list_bitmaps(struct super_block *sb,
                   struct reiserfs_list_bitmap *jb_array,
                   unsigned int bmap_nr)
{
    int i;
    int failed = 0;
    struct reiserfs_list_bitmap *jb;
    int mem = bmap_nr * sizeof(struct reiserfs_bitmap_node *);

    for (i = 0; i < JOURNAL_NUM_BITMAPS; i++) {
        jb = jb_array + i;
        jb->journal_list = NULL;
        jb->bitmaps = vzalloc(mem);
        if (!jb->bitmaps) {
            reiserfs_warning(sb, "clm-2000", "unable to "
                     "allocate bitmaps for journal lists");
            failed = 1;
            break;
        }
    }
    if (failed) {
        free_list_bitmaps(sb, jb_array);
        return -1;
    }
    return 0;
}

/*
** find an available list bitmap.  If you can't find one, flush a commit list
** and try again
*/
static struct reiserfs_list_bitmap *get_list_bitmap(struct super_block *sb,
                            struct reiserfs_journal_list
                            *jl)
{
    int i, j;
    struct reiserfs_journal *journal = SB_JOURNAL(sb);
    struct reiserfs_list_bitmap *jb = NULL;

    for (j = 0; j < (JOURNAL_NUM_BITMAPS * 3); j++) {
        i = journal->j_list_bitmap_index;
        journal->j_list_bitmap_index = (i + 1) % JOURNAL_NUM_BITMAPS;
        jb = journal->j_list_bitmap + i;
        if (journal->j_list_bitmap[i].journal_list) {
            flush_commit_list(sb,
                      journal->j_list_bitmap[i].
                      journal_list, 1);
            if (!journal->j_list_bitmap[i].journal_list) {
                break;
            }
        } else {
            break;
        }
    }
    if (jb->journal_list) { /* double check to make sure if flushed correctly */
        return NULL;
    }
    jb->journal_list = jl;
    return jb;
}

/*
** allocates a new chunk of X nodes, and links them all together as a list.
** Uses the cnode->next and cnode->prev pointers
** returns NULL on failure
*/
static struct reiserfs_journal_cnode *allocate_cnodes(int num_cnodes)
{
    struct reiserfs_journal_cnode *head;
    int i;
    if (num_cnodes <= 0) {
        return NULL;
    }
    head = vzalloc(num_cnodes * sizeof(struct reiserfs_journal_cnode));
    if (!head) {
        return NULL;
    }
    head[0].prev = NULL;
    head[0].next = head + 1;
    for (i = 1; i < num_cnodes; i++) {
        head[i].prev = head + (i - 1);
        head[i].next = head + (i + 1);  /* if last one, overwrite it after the if */
    }
    head[num_cnodes - 1].next = NULL;
    return head;
}

/*
** pulls a cnode off the free list, or returns NULL on failure
*/
static struct reiserfs_journal_cnode *get_cnode(struct super_block *sb)
{
    struct reiserfs_journal_cnode *cn;
    struct reiserfs_journal *journal = SB_JOURNAL(sb);

    reiserfs_check_lock_depth(sb, "get_cnode");

    if (journal->j_cnode_free <= 0) {
        return NULL;
    }
    journal->j_cnode_used++;
    journal->j_cnode_free--;
    cn = journal->j_cnode_free_list;
    if (!cn) {
        return cn;
    }
    if (cn->next) {
        cn->next->prev = NULL;
    }
    journal->j_cnode_free_list = cn->next;
    memset(cn, 0, sizeof(struct reiserfs_journal_cnode));
    return cn;
}

/*
** returns a cnode to the free list
*/
static void free_cnode(struct super_block *sb,
               struct reiserfs_journal_cnode *cn)
{
    struct reiserfs_journal *journal = SB_JOURNAL(sb);

    reiserfs_check_lock_depth(sb, "free_cnode");

    journal->j_cnode_used--;
    journal->j_cnode_free++;
    /* memset(cn, 0, sizeof(struct reiserfs_journal_cnode)) ; */
    cn->next = journal->j_cnode_free_list;
    if (journal->j_cnode_free_list) {
        journal->j_cnode_free_list->prev = cn;
    }
    cn->prev = NULL;    /* not needed with the memset, but I might kill the memset, and forget to do this */
    journal->j_cnode_free_list = cn;
}

static void clear_prepared_bits(struct buffer_head *bh)
{
    clear_buffer_journal_prepared(bh);
    clear_buffer_journal_restore_dirty(bh);
}

/* return a cnode with same dev, block number and size in table, or null if not found */
static inline struct reiserfs_journal_cnode *get_journal_hash_dev(struct
                                  super_block
                                  *sb,
                                  struct
                                  reiserfs_journal_cnode
                                  **table,
                                  long bl)
{
    struct reiserfs_journal_cnode *cn;
    cn = journal_hash(table, sb, bl);
    while (cn) {
        if (cn->blocknr == bl && cn->sb == sb)
            return cn;
        cn = cn->hnext;
    }
    return (struct reiserfs_journal_cnode *)0;
}

/*
** this actually means 'can this block be reallocated yet?'.  If you set search_all, a block can only be allocated
** if it is not in the current transaction, was not freed by the current transaction, and has no chance of ever
** being overwritten by a replay after crashing.
**
** If you don't set search_all, a block can only be allocated if it is not in the current transaction.  Since deleting
** a block removes it from the current transaction, this case should never happen.  If you don't set search_all, make
** sure you never write the block without logging it.
**
** next_zero_bit is a suggestion about the next block to try for find_forward.
** when bl is rejected because it is set in a journal list bitmap, we search
** for the next zero bit in the bitmap that rejected bl.  Then, we return that
** through next_zero_bit for find_forward to try.
**
** Just because we return something in next_zero_bit does not mean we won't
** reject it on the next call to reiserfs_in_journal
**
*/
int reiserfs_in_journal(struct super_block *sb,
            unsigned int bmap_nr, int bit_nr, int search_all,
            b_blocknr_t * next_zero_bit)
{
    struct reiserfs_journal *journal = SB_JOURNAL(sb);
    struct reiserfs_journal_cnode *cn;
    struct reiserfs_list_bitmap *jb;
    int i;
    unsigned long bl;

    *next_zero_bit = 0; /* always start this at zero. */

    PROC_INFO_INC(sb, journal.in_journal);
    /* If we aren't doing a search_all, this is a metablock, and it will be logged before use.
     ** if we crash before the transaction that freed it commits,  this transaction won't
     ** have committed either, and the block will never be written
     */
    if (search_all) {
        for (i = 0; i < JOURNAL_NUM_BITMAPS; i++) {
            PROC_INFO_INC(sb, journal.in_journal_bitmap);
            jb = journal->j_list_bitmap + i;
            if (jb->journal_list && jb->bitmaps[bmap_nr] &&
                test_bit(bit_nr,
                     (unsigned long *)jb->bitmaps[bmap_nr]->
                     data)) {
                *next_zero_bit =
                    find_next_zero_bit((unsigned long *)
                               (jb->bitmaps[bmap_nr]->
                            data),
                               sb->s_blocksize << 3,
                               bit_nr + 1);
                return 1;
            }
        }
    }

    bl = bmap_nr * (sb->s_blocksize << 3) + bit_nr;
    /* is it in any old transactions? */
    if (search_all
        && (cn =
        get_journal_hash_dev(sb, journal->j_list_hash_table, bl))) {
        return 1;
    }

    /* is it in the current transaction.  This should never happen */
    if ((cn = get_journal_hash_dev(sb, journal->j_hash_table, bl))) {
        BUG();
        return 1;
    }

    PROC_INFO_INC(sb, journal.in_journal_reusable);
    /* safe for reuse */
    return 0;
}

/* insert cn into table
*/
static inline void insert_journal_hash(struct reiserfs_journal_cnode **table,
                       struct reiserfs_journal_cnode *cn)
{
    struct reiserfs_journal_cnode *cn_orig;

    cn_orig = journal_hash(table, cn->sb, cn->blocknr);
    cn->hnext = cn_orig;
    cn->hprev = NULL;
    if (cn_orig) {
        cn_orig->hprev = cn;
    }
    journal_hash(table, cn->sb, cn->blocknr) = cn;
}

/* lock the current transaction */
static inline void lock_journal(struct super_block *sb)
{
    PROC_INFO_INC(sb, journal.lock_journal);

    reiserfs_mutex_lock_safe(&SB_JOURNAL(sb)->j_mutex, sb);
}

/* unlock the current transaction */
static inline void unlock_journal(struct super_block *sb)
{
    mutex_unlock(&SB_JOURNAL(sb)->j_mutex);
}

static inline void get_journal_list(struct reiserfs_journal_list *jl)
{
    jl->j_refcount++;
}

static inline void put_journal_list(struct super_block *s,
                    struct reiserfs_journal_list *jl)
{
    if (jl->j_refcount < 1) {
        reiserfs_panic(s, "journal-2", "trans id %u, refcount at %d",
                   jl->j_trans_id, jl->j_refcount);
    }
    if (--jl->j_refcount == 0)
        kfree(jl);
}

/*
** this used to be much more involved, and I'm keeping it just in case things get ugly again.
** it gets called by flush_commit_list, and cleans up any data stored about blocks freed during a
** transaction.
*/
static void cleanup_freed_for_journal_list(struct super_block *sb,
                       struct reiserfs_journal_list *jl)
{

    struct reiserfs_list_bitmap *jb = jl->j_list_bitmap;
    if (jb) {
        cleanup_bitmap_list(sb, jb);
    }
    jl->j_list_bitmap->journal_list = NULL;
    jl->j_list_bitmap = NULL;
}

static int journal_list_still_alive(struct super_block *s,
                    unsigned int trans_id)
{
    struct reiserfs_journal *journal = SB_JOURNAL(s);
    struct list_head *entry = &journal->j_journal_list;
    struct reiserfs_journal_list *jl;

    if (!list_empty(entry)) {
        jl = JOURNAL_LIST_ENTRY(entry->next);
        if (jl->j_trans_id <= trans_id) {
            return 1;
        }
    }
    return 0;
}

/*
 * If page->mapping was null, we failed to truncate this page for
 * some reason.  Most likely because it was truncated after being
 * logged via data=journal.
 *
 * This does a check to see if the buffer belongs to one of these
 * lost pages before doing the final put_bh.  If page->mapping was
 * null, it tries to free buffers on the page, which should make the
 * final page_cache_release drop the page from the lru.
 */
static void release_buffer_page(struct buffer_head *bh)
{
    struct page *page = bh->b_page;
    if (!page->mapping && trylock_page(page)) {
        page_cache_get(page);
        put_bh(bh);
        if (!page->mapping)
            try_to_free_buffers(page);
        unlock_page(page);
        page_cache_release(page);
    } else {
        put_bh(bh);
    }
}

static void reiserfs_end_buffer_io_sync(struct buffer_head *bh, int uptodate)
{
    char b[BDEVNAME_SIZE];

    if (buffer_journaled(bh)) {
        reiserfs_warning(NULL, "clm-2084",
                 "pinned buffer %lu:%s sent to disk",
                 bh->b_blocknr, bdevname(bh->b_bdev, b));
    }
    if (uptodate)
        set_buffer_uptodate(bh);
    else
        clear_buffer_uptodate(bh);

    unlock_buffer(bh);
    release_buffer_page(bh);
}

static void reiserfs_end_ordered_io(struct buffer_head *bh, int uptodate)
{
    if (uptodate)
        set_buffer_uptodate(bh);
    else
        clear_buffer_uptodate(bh);
    unlock_buffer(bh);
    put_bh(bh);
}

static void submit_logged_buffer(struct buffer_head *bh)
{
    get_bh(bh);
    bh->b_end_io = reiserfs_end_buffer_io_sync;
    clear_buffer_journal_new(bh);
    clear_buffer_dirty(bh);
    if (!test_clear_buffer_journal_test(bh))
        BUG();
    if (!buffer_uptodate(bh))
        BUG();
    submit_bh(WRITE, bh);
}

static void submit_ordered_buffer(struct buffer_head *bh)
{
    get_bh(bh);
    bh->b_end_io = reiserfs_end_ordered_io;
    clear_buffer_dirty(bh);
    if (!buffer_uptodate(bh))
        BUG();
    submit_bh(WRITE, bh);
}

#define CHUNK_SIZE 32
struct buffer_chunk {
    struct buffer_head *bh[CHUNK_SIZE];
    int nr;
};

static void write_chunk(struct buffer_chunk *chunk)
{
    int i;
    for (i = 0; i < chunk->nr; i++) {
        submit_logged_buffer(chunk->bh[i]);
    }
    chunk->nr = 0;
}

static void write_ordered_chunk(struct buffer_chunk *chunk)
{
    int i;
    for (i = 0; i < chunk->nr; i++) {
        submit_ordered_buffer(chunk->bh[i]);
    }
    chunk->nr = 0;
}

static int add_to_chunk(struct buffer_chunk *chunk, struct buffer_head *bh,
            spinlock_t * lock, void (fn) (struct buffer_chunk *))
{
    int ret = 0;
    BUG_ON(chunk->nr >= CHUNK_SIZE);
    chunk->bh[chunk->nr++] = bh;
    if (chunk->nr >= CHUNK_SIZE) {
        ret = 1;
        if (lock)
            spin_unlock(lock);
        fn(chunk);
        if (lock)
            spin_lock(lock);
    }
    return ret;
}

static atomic_t nr_reiserfs_jh = ATOMIC_INIT(0);
static struct reiserfs_jh *alloc_jh(void)
{
    struct reiserfs_jh *jh;
    while (1) {
        jh = kmalloc(sizeof(*jh), GFP_NOFS);
        if (jh) {
            atomic_inc(&nr_reiserfs_jh);
            return jh;
        }
        yield();
    }
}

/*
 * we want to free the jh when the buffer has been written
 * and waited on
 */
void reiserfs_free_jh(struct buffer_head *bh)
{
    struct reiserfs_jh *jh;

    jh = bh->b_private;
    if (jh) {
        bh->b_private = NULL;
        jh->bh = NULL;
        list_del_init(&jh->list);
        kfree(jh);
        if (atomic_read(&nr_reiserfs_jh) <= 0)
            BUG();
        atomic_dec(&nr_reiserfs_jh);
        put_bh(bh);
    }
}

static inline int __add_jh(struct reiserfs_journal *j, struct buffer_head *bh,
               int tail)
{
    struct reiserfs_jh *jh;

    if (bh->b_private) {
        spin_lock(&j->j_dirty_buffers_lock);
        if (!bh->b_private) {
            spin_unlock(&j->j_dirty_buffers_lock);
            goto no_jh;
        }
        jh = bh->b_private;
        list_del_init(&jh->list);
    } else {
          no_jh:
        get_bh(bh);
        jh = alloc_jh();
        spin_lock(&j->j_dirty_buffers_lock);
        /* buffer must be locked for __add_jh, should be able to have
         * two adds at the same time
         */
        BUG_ON(bh->b_private);
        jh->bh = bh;
        bh->b_private = jh;
    }
    jh->jl = j->j_current_jl;
    if (tail)
        list_add_tail(&jh->list, &jh->jl->j_tail_bh_list);
    else {
        list_add_tail(&jh->list, &jh->jl->j_bh_list);
    }
    spin_unlock(&j->j_dirty_buffers_lock);
    return 0;
}

int reiserfs_add_tail_list(struct inode *inode, struct buffer_head *bh)
{
    return __add_jh(SB_JOURNAL(inode->i_sb), bh, 1);
}
int reiserfs_add_ordered_list(struct inode *inode, struct buffer_head *bh)
{
    return __add_jh(SB_JOURNAL(inode->i_sb), bh, 0);
}

#define JH_ENTRY(l) list_entry((l), struct reiserfs_jh, list)
static int write_ordered_buffers(spinlock_t * lock,
                 struct reiserfs_journal *j,
                 struct reiserfs_journal_list *jl,
                 struct list_head *list)
{
    struct buffer_head *bh;
    struct reiserfs_jh *jh;
    int ret = j->j_errno;
    struct buffer_chunk chunk;
    struct list_head tmp;
    INIT_LIST_HEAD(&tmp);

    chunk.nr = 0;
    spin_lock(lock);
    while (!list_empty(list)) {
        jh = JH_ENTRY(list->next);
        bh = jh->bh;
        get_bh(bh);
        if (!trylock_buffer(bh)) {
            if (!buffer_dirty(bh)) {
                list_move(&jh->list, &tmp);
                goto loop_next;
            }
            spin_unlock(lock);
            if (chunk.nr)
                write_ordered_chunk(&chunk);
            wait_on_buffer(bh);
            cond_resched();
            spin_lock(lock);
            goto loop_next;
        }
        /* in theory, dirty non-uptodate buffers should never get here,
         * but the upper layer io error paths still have a few quirks.
         * Handle them here as gracefully as we can
         */
        if (!buffer_uptodate(bh) && buffer_dirty(bh)) {
            clear_buffer_dirty(bh);
            ret = -EIO;
        }
        if (buffer_dirty(bh)) {
            list_move(&jh->list, &tmp);
            add_to_chunk(&chunk, bh, lock, write_ordered_chunk);
        } else {
            reiserfs_free_jh(bh);
            unlock_buffer(bh);
        }
          loop_next:
        put_bh(bh);
        cond_resched_lock(lock);
    }
    if (chunk.nr) {
        spin_unlock(lock);
        write_ordered_chunk(&chunk);
        spin_lock(lock);
    }
    while (!list_empty(&tmp)) {
        jh = JH_ENTRY(tmp.prev);
        bh = jh->bh;
        get_bh(bh);
        reiserfs_free_jh(bh);

        if (buffer_locked(bh)) {
            spin_unlock(lock);
            wait_on_buffer(bh);
            spin_lock(lock);
        }
        if (!buffer_uptodate(bh)) {
            ret = -EIO;
        }
        /* ugly interaction with invalidatepage here.
         * reiserfs_invalidate_page will pin any buffer that has a valid
         * journal head from an older transaction.  If someone else sets
         * our buffer dirty after we write it in the first loop, and
         * then someone truncates the page away, nobody will ever write
         * the buffer. We're safe if we write the page one last time
         * after freeing the journal header.
         */
        if (buffer_dirty(bh) && unlikely(bh->b_page->mapping == NULL)) {
            spin_unlock(lock);
            ll_rw_block(WRITE, 1, &bh);
            spin_lock(lock);
        }
        put_bh(bh);
        cond_resched_lock(lock);
    }
    spin_unlock(lock);
    return ret;
}

static int flush_older_commits(struct super_block *s,
                   struct reiserfs_journal_list *jl)
{
    struct reiserfs_journal *journal = SB_JOURNAL(s);
    struct reiserfs_journal_list *other_jl;
    struct reiserfs_journal_list *first_jl;
    struct list_head *entry;
    unsigned int trans_id = jl->j_trans_id;
    unsigned int other_trans_id;
    unsigned int first_trans_id;

      find_first:
    /*
     * first we walk backwards to find the oldest uncommitted transation
     */
    first_jl = jl;
    entry = jl->j_list.prev;
    while (1) {
        other_jl = JOURNAL_LIST_ENTRY(entry);
        if (entry == &journal->j_journal_list ||
            atomic_read(&other_jl->j_older_commits_done))
            break;

        first_jl = other_jl;
        entry = other_jl->j_list.prev;
    }

    /* if we didn't find any older uncommitted transactions, return now */
    if (first_jl == jl) {
        return 0;
    }

    first_trans_id = first_jl->j_trans_id;

    entry = &first_jl->j_list;
    while (1) {
        other_jl = JOURNAL_LIST_ENTRY(entry);
        other_trans_id = other_jl->j_trans_id;

        if (other_trans_id < trans_id) {
            if (atomic_read(&other_jl->j_commit_left) != 0) {
                flush_commit_list(s, other_jl, 0);

                /* list we were called with is gone, return */
                if (!journal_list_still_alive(s, trans_id))
                    return 1;

                /* the one we just flushed is gone, this means all
                 * older lists are also gone, so first_jl is no longer
                 * valid either.  Go back to the beginning.
                 */
                if (!journal_list_still_alive
                    (s, other_trans_id)) {
                    goto find_first;
                }
            }
            entry = entry->next;
            if (entry == &journal->j_journal_list)
                return 0;
        } else {
            return 0;
        }
    }
    return 0;
}

static int reiserfs_async_progress_wait(struct super_block *s)
{
    struct reiserfs_journal *j = SB_JOURNAL(s);

    if (atomic_read(&j->j_async_throttle)) {
        reiserfs_write_unlock(s);
        congestion_wait(BLK_RW_ASYNC, HZ / 10);
        reiserfs_write_lock(s);
    }

    return 0;
}

/*
** if this journal list still has commit blocks unflushed, send them to disk.
**
** log areas must be flushed in order (transaction 2 can't commit before transaction 1)
** Before the commit block can by written, every other log block must be safely on disk
**
*/
static int flush_commit_list(struct super_block *s,
                 struct reiserfs_journal_list *jl, int flushall)
{
    int i;
    b_blocknr_t bn;
    struct buffer_head *tbh = NULL;
    unsigned int trans_id = jl->j_trans_id;
    struct reiserfs_journal *journal = SB_JOURNAL(s);
    int retval = 0;
    int write_len;

    reiserfs_check_lock_depth(s, "flush_commit_list");

    if (atomic_read(&jl->j_older_commits_done)) {
        return 0;
    }

    /* before we can put our commit blocks on disk, we have to make sure everyone older than
     ** us is on disk too
     */
    BUG_ON(jl->j_len <= 0);
    BUG_ON(trans_id == journal->j_trans_id);

    get_journal_list(jl);
    if (flushall) {
        if (flush_older_commits(s, jl) == 1) {
            /* list disappeared during flush_older_commits.  return */
            goto put_jl;
        }
    }

    /* make sure nobody is trying to flush this one at the same time */
    reiserfs_mutex_lock_safe(&jl->j_commit_mutex, s);

    if (!journal_list_still_alive(s, trans_id)) {
        mutex_unlock(&jl->j_commit_mutex);
        goto put_jl;
    }
    BUG_ON(jl->j_trans_id == 0);

    /* this commit is done, exit */
    if (atomic_read(&(jl->j_commit_left)) <= 0) {
        if (flushall) {
            atomic_set(&(jl->j_older_commits_done), 1);
        }
        mutex_unlock(&jl->j_commit_mutex);
        goto put_jl;
    }

    if (!list_empty(&jl->j_bh_list)) {
        int ret;

        /*
         * We might sleep in numerous places inside
         * write_ordered_buffers. Relax the write lock.
         */
        reiserfs_write_unlock(s);
        ret = write_ordered_buffers(&journal->j_dirty_buffers_lock,
                        journal, jl, &jl->j_bh_list);
        if (ret < 0 && retval == 0)
            retval = ret;
        reiserfs_write_lock(s);
    }
    BUG_ON(!list_empty(&jl->j_bh_list));
    /*
     * for the description block and all the log blocks, submit any buffers
     * that haven't already reached the disk.  Try to write at least 256
     * log blocks. later on, we will only wait on blocks that correspond
     * to this transaction, but while we're unplugging we might as well
     * get a chunk of data on there.
     */
    atomic_inc(&journal->j_async_throttle);
    write_len = jl->j_len + 1;
    if (write_len < 256)
        write_len = 256;
    for (i = 0 ; i < write_len ; i++) {
        bn = SB_ONDISK_JOURNAL_1st_BLOCK(s) + (jl->j_start + i) %
            SB_ONDISK_JOURNAL_SIZE(s);
        tbh = journal_find_get_block(s, bn);
        if (tbh) {
            if (buffer_dirty(tbh)) {
                    reiserfs_write_unlock(s);
                ll_rw_block(WRITE, 1, &tbh);
                reiserfs_write_lock(s);
            }
            put_bh(tbh) ;
        }
    }
    atomic_dec(&journal->j_async_throttle);

    for (i = 0; i < (jl->j_len + 1); i++) {
        bn = SB_ONDISK_JOURNAL_1st_BLOCK(s) +
            (jl->j_start + i) % SB_ONDISK_JOURNAL_SIZE(s);
        tbh = journal_find_get_block(s, bn);

        reiserfs_write_unlock(s);
        wait_on_buffer(tbh);
        reiserfs_write_lock(s);
        // since we're using ll_rw_blk above, it might have skipped over
        // a locked buffer.  Double check here
        //
        /* redundant, sync_dirty_buffer() checks */
        if (buffer_dirty(tbh)) {
            reiserfs_write_unlock(s);
            sync_dirty_buffer(tbh);
            reiserfs_write_lock(s);
        }
        if (unlikely(!buffer_uptodate(tbh))) {
#ifdef CONFIG_REISERFS_CHECK
            reiserfs_warning(s, "journal-601",
                     "buffer write failed");
#endif
            retval = -EIO;
        }
        put_bh(tbh);    /* once for journal_find_get_block */
        put_bh(tbh);    /* once due to original getblk in do_journal_end */
        atomic_dec(&(jl->j_commit_left));
    }

    BUG_ON(atomic_read(&(jl->j_commit_left)) != 1);

    /* If there was a write error in the journal - we can't commit
     * this transaction - it will be invalid and, if successful,
     * will just end up propagating the write error out to
     * the file system. */
    if (likely(!retval && !reiserfs_is_journal_aborted (journal))) {
        if (buffer_dirty(jl->j_commit_bh))
            BUG();
        mark_buffer_dirty(jl->j_commit_bh) ;
        reiserfs_write_unlock(s);
        if (reiserfs_barrier_flush(s))
            __sync_dirty_buffer(jl->j_commit_bh, WRITE_FLUSH_FUA);
        else
            sync_dirty_buffer(jl->j_commit_bh);
        reiserfs_write_lock(s);
    }

    /* If there was a write error in the journal - we can't commit this
     * transaction - it will be invalid and, if successful, will just end
     * up propagating the write error out to the filesystem. */
    if (unlikely(!buffer_uptodate(jl->j_commit_bh))) {
#ifdef CONFIG_REISERFS_CHECK
        reiserfs_warning(s, "journal-615", "buffer write failed");
#endif
        retval = -EIO;
    }
    bforget(jl->j_commit_bh);
    if (journal->j_last_commit_id != 0 &&
        (jl->j_trans_id - journal->j_last_commit_id) != 1) {
        reiserfs_warning(s, "clm-2200", "last commit %lu, current %lu",
                 journal->j_last_commit_id, jl->j_trans_id);
    }
    journal->j_last_commit_id = jl->j_trans_id;

    /* now, every commit block is on the disk.  It is safe to allow blocks freed during this transaction to be reallocated */
    cleanup_freed_for_journal_list(s, jl);

    retval = retval ? retval : journal->j_errno;

    /* mark the metadata dirty */
    if (!retval)
        dirty_one_transaction(s, jl);
    atomic_dec(&(jl->j_commit_left));

    if (flushall) {
        atomic_set(&(jl->j_older_commits_done), 1);
    }
    mutex_unlock(&jl->j_commit_mutex);
      put_jl:
    put_journal_list(s, jl);

    if (retval)
        reiserfs_abort(s, retval, "Journal write error in %s",
                   __func__);
    return retval;
}

/*
** flush_journal_list frequently needs to find a newer transaction for a given block.  This does that, or
** returns NULL if it can't find anything
*/
static struct reiserfs_journal_list *find_newer_jl_for_cn(struct
                              reiserfs_journal_cnode
                              *cn)
{
    struct super_block *sb = cn->sb;
    b_blocknr_t blocknr = cn->blocknr;

    cn = cn->hprev;
    while (cn) {
        if (cn->sb == sb && cn->blocknr == blocknr && cn->jlist) {
            return cn->jlist;
        }
        cn = cn->hprev;
    }
    return NULL;
}

static int newer_jl_done(struct reiserfs_journal_cnode *cn)
{
    struct super_block *sb = cn->sb;
    b_blocknr_t blocknr = cn->blocknr;

    cn = cn->hprev;
    while (cn) {
        if (cn->sb == sb && cn->blocknr == blocknr && cn->jlist &&
            atomic_read(&cn->jlist->j_commit_left) != 0)
                    return 0;
        cn = cn->hprev;
    }
    return 1;
}

static void remove_journal_hash(struct super_block *,
                struct reiserfs_journal_cnode **,
                struct reiserfs_journal_list *, unsigned long,
                int);

/*
** once all the real blocks have been flushed, it is safe to remove them from the
** journal list for this transaction.  Aside from freeing the cnode, this also allows the
** block to be reallocated for data blocks if it had been deleted.
*/
static void remove_all_from_journal_list(struct super_block *sb,
                     struct reiserfs_journal_list *jl,
                     int debug)
{
    struct reiserfs_journal *journal = SB_JOURNAL(sb);
    struct reiserfs_journal_cnode *cn, *last;
    cn = jl->j_realblock;

    /* which is better, to lock once around the whole loop, or
     ** to lock for each call to remove_journal_hash?
     */
    while (cn) {
        if (cn->blocknr != 0) {
            if (debug) {
                reiserfs_warning(sb, "reiserfs-2201",
                         "block %u, bh is %d, state %ld",
                         cn->blocknr, cn->bh ? 1 : 0,
                         cn->state);
            }
            cn->state = 0;
            remove_journal_hash(sb, journal->j_list_hash_table,
                        jl, cn->blocknr, 1);
        }
        last = cn;
        cn = cn->next;
        free_cnode(sb, last);
    }
    jl->j_realblock = NULL;
}

/*
** if this timestamp is greater than the timestamp we wrote last to the header block, write it to the header block.
** once this is done, I can safely say the log area for this transaction won't ever be replayed, and I can start
** releasing blocks in this transaction for reuse as data blocks.
** called by flush_journal_list, before it calls remove_all_from_journal_list
**
*/
static int _update_journal_header_block(struct super_block *sb,
                    unsigned long offset,
                    unsigned int trans_id)
{
    struct reiserfs_journal_header *jh;
    struct reiserfs_journal *journal = SB_JOURNAL(sb);

    if (reiserfs_is_journal_aborted(journal))
        return -EIO;

    if (trans_id >= journal->j_last_flush_trans_id) {
        if (buffer_locked((journal->j_header_bh))) {
            reiserfs_write_unlock(sb);
            wait_on_buffer((journal->j_header_bh));
            reiserfs_write_lock(sb);
            if (unlikely(!buffer_uptodate(journal->j_header_bh))) {
#ifdef CONFIG_REISERFS_CHECK
                reiserfs_warning(sb, "journal-699",
                         "buffer write failed");
#endif
                return -EIO;
            }
        }
        journal->j_last_flush_trans_id = trans_id;
        journal->j_first_unflushed_offset = offset;
        jh = (struct reiserfs_journal_header *)(journal->j_header_bh->
                            b_data);
        jh->j_last_flush_trans_id = cpu_to_le32(trans_id);
        jh->j_first_unflushed_offset = cpu_to_le32(offset);
        jh->j_mount_id = cpu_to_le32(journal->j_mount_id);

        set_buffer_dirty(journal->j_header_bh);
        reiserfs_write_unlock(sb);

        if (reiserfs_barrier_flush(sb))
            __sync_dirty_buffer(journal->j_header_bh, WRITE_FLUSH_FUA);
        else
            sync_dirty_buffer(journal->j_header_bh);

        reiserfs_write_lock(sb);
        if (!buffer_uptodate(journal->j_header_bh)) {
            reiserfs_warning(sb, "journal-837",
                     "IO error during journal replay");
            return -EIO;
        }
    }
    return 0;
}

static int update_journal_header_block(struct super_block *sb,
                       unsigned long offset,
                       unsigned int trans_id)
{
    return _update_journal_header_block(sb, offset, trans_id);
}

/*
** flush any and all journal lists older than you are
** can only be called from flush_journal_list
*/
static int flush_older_journal_lists(struct super_block *sb,
                     struct reiserfs_journal_list *jl)
{
    struct list_head *entry;
    struct reiserfs_journal_list *other_jl;
    struct reiserfs_journal *journal = SB_JOURNAL(sb);
    unsigned int trans_id = jl->j_trans_id;

    /* we know we are the only ones flushing things, no extra race
     * protection is required.
     */
      restart:
    entry = journal->j_journal_list.next;
    /* Did we wrap? */
    if (entry == &journal->j_journal_list)
        return 0;
    other_jl = JOURNAL_LIST_ENTRY(entry);
    if (other_jl->j_trans_id < trans_id) {
        BUG_ON(other_jl->j_refcount <= 0);
        /* do not flush all */
        flush_journal_list(sb, other_jl, 0);

        /* other_jl is now deleted from the list */
        goto restart;
    }
    return 0;
}

static void del_from_work_list(struct super_block *s,
                   struct reiserfs_journal_list *jl)
{
    struct reiserfs_journal *journal = SB_JOURNAL(s);
    if (!list_empty(&jl->j_working_list)) {
        list_del_init(&jl->j_working_list);
        journal->j_num_work_lists--;
    }
}

/* flush a journal list, both commit and real blocks
**
** always set flushall to 1, unless you are calling from inside
** flush_journal_list
**
** IMPORTANT.  This can only be called while there are no journal writers,
** and the journal is locked.  That means it can only be called from
** do_journal_end, or by journal_release
*/
static int flush_journal_list(struct super_block *s,
                  struct reiserfs_journal_list *jl, int flushall)
{
    struct reiserfs_journal_list *pjl;
    struct reiserfs_journal_cnode *cn, *last;
    int count;
    int was_jwait = 0;
    int was_dirty = 0;
    struct buffer_head *saved_bh;
    unsigned long j_len_saved = jl->j_len;
    struct reiserfs_journal *journal = SB_JOURNAL(s);
    int err = 0;

    BUG_ON(j_len_saved <= 0);

    if (atomic_read(&journal->j_wcount) != 0) {
        reiserfs_warning(s, "clm-2048", "called with wcount %d",
                 atomic_read(&journal->j_wcount));
    }
    BUG_ON(jl->j_trans_id == 0);

    /* if flushall == 0, the lock is already held */
    if (flushall) {
        reiserfs_mutex_lock_safe(&journal->j_flush_mutex, s);
    } else if (mutex_trylock(&journal->j_flush_mutex)) {
        BUG();
    }

    count = 0;
    if (j_len_saved > journal->j_trans_max) {
        reiserfs_panic(s, "journal-715", "length is %lu, trans id %lu",
                   j_len_saved, jl->j_trans_id);
        return 0;
    }

    /* if all the work is already done, get out of here */
    if (atomic_read(&(jl->j_nonzerolen)) <= 0 &&
        atomic_read(&(jl->j_commit_left)) <= 0) {
        goto flush_older_and_return;
    }

    /* start by putting the commit list on disk.  This will also flush
     ** the commit lists of any olders transactions
     */
    flush_commit_list(s, jl, 1);

    if (!(jl->j_state & LIST_DIRTY)
        && !reiserfs_is_journal_aborted(journal))
        BUG();

    /* are we done now? */
    if (atomic_read(&(jl->j_nonzerolen)) <= 0 &&
        atomic_read(&(jl->j_commit_left)) <= 0) {
        goto flush_older_and_return;
    }

    /* loop through each cnode, see if we need to write it,
     ** or wait on a more recent transaction, or just ignore it
     */
    if (atomic_read(&(journal->j_wcount)) != 0) {
        reiserfs_panic(s, "journal-844", "journal list is flushing, "
                   "wcount is not 0");
    }
    cn = jl->j_realblock;
    while (cn) {
        was_jwait = 0;
        was_dirty = 0;
        saved_bh = NULL;
        /* blocknr of 0 is no longer in the hash, ignore it */
        if (cn->blocknr == 0) {
            goto free_cnode;
        }

        /* This transaction failed commit. Don't write out to the disk */
        if (!(jl->j_state & LIST_DIRTY))
            goto free_cnode;

        pjl = find_newer_jl_for_cn(cn);
        /* the order is important here.  We check pjl to make sure we
         ** don't clear BH_JDirty_wait if we aren't the one writing this
         ** block to disk
         */
        if (!pjl && cn->bh) {
            saved_bh = cn->bh;

            /* we do this to make sure nobody releases the buffer while
             ** we are working with it
             */
            get_bh(saved_bh);

            if (buffer_journal_dirty(saved_bh)) {
                BUG_ON(!can_dirty(cn));
                was_jwait = 1;
                was_dirty = 1;
            } else if (can_dirty(cn)) {
                /* everything with !pjl && jwait should be writable */
                BUG();
            }
        }

        /* if someone has this block in a newer transaction, just make
         ** sure they are committed, and don't try writing it to disk
         */
        if (pjl) {
            if (atomic_read(&pjl->j_commit_left))
                flush_commit_list(s, pjl, 1);
            goto free_cnode;
        }

        /* bh == NULL when the block got to disk on its own, OR,
         ** the block got freed in a future transaction
         */
        if (saved_bh == NULL) {
            goto free_cnode;
        }

        /* this should never happen.  kupdate_one_transaction has this list
         ** locked while it works, so we should never see a buffer here that
         ** is not marked JDirty_wait
         */
        if ((!was_jwait) && !buffer_locked(saved_bh)) {
            reiserfs_warning(s, "journal-813",
                     "BAD! buffer %llu %cdirty %cjwait, "
                     "not in a newer tranasction",
                     (unsigned long long)saved_bh->
                     b_blocknr, was_dirty ? ' ' : '!',
                     was_jwait ? ' ' : '!');
        }
        if (was_dirty) {
            /* we inc again because saved_bh gets decremented at free_cnode */
            get_bh(saved_bh);
            set_bit(BLOCK_NEEDS_FLUSH, &cn->state);
            lock_buffer(saved_bh);
            BUG_ON(cn->blocknr != saved_bh->b_blocknr);
            if (buffer_dirty(saved_bh))
                submit_logged_buffer(saved_bh);
            else
                unlock_buffer(saved_bh);
            count++;
        } else {
            reiserfs_warning(s, "clm-2082",
                     "Unable to flush buffer %llu in %s",
                     (unsigned long long)saved_bh->
                     b_blocknr, __func__);
        }
          free_cnode:
        last = cn;
        cn = cn->next;
        if (saved_bh) {
            /* we incremented this to keep others from taking the buffer head away */
            put_bh(saved_bh);
            if (atomic_read(&(saved_bh->b_count)) < 0) {
                reiserfs_warning(s, "journal-945",
                         "saved_bh->b_count < 0");
            }
        }
    }
    if (count > 0) {
        cn = jl->j_realblock;
        while (cn) {
            if (test_bit(BLOCK_NEEDS_FLUSH, &cn->state)) {
                if (!cn->bh) {
                    reiserfs_panic(s, "journal-1011",
                               "cn->bh is NULL");
                }

                reiserfs_write_unlock(s);
                wait_on_buffer(cn->bh);
                reiserfs_write_lock(s);

                if (!cn->bh) {
                    reiserfs_panic(s, "journal-1012",
                               "cn->bh is NULL");
                }
                if (unlikely(!buffer_uptodate(cn->bh))) {
#ifdef CONFIG_REISERFS_CHECK
                    reiserfs_warning(s, "journal-949",
                             "buffer write failed");
#endif
                    err = -EIO;
                }
                /* note, we must clear the JDirty_wait bit after the up to date
                 ** check, otherwise we race against our flushpage routine
                 */
                BUG_ON(!test_clear_buffer_journal_dirty
                       (cn->bh));

                /* drop one ref for us */
                put_bh(cn->bh);
                /* drop one ref for journal_mark_dirty */
                release_buffer_page(cn->bh);
            }
            cn = cn->next;
        }
    }

    if (err)
        reiserfs_abort(s, -EIO,
                   "Write error while pushing transaction to disk in %s",
                   __func__);
      flush_older_and_return:

    /* before we can update the journal header block, we _must_ flush all
     ** real blocks from all older transactions to disk.  This is because
     ** once the header block is updated, this transaction will not be
     ** replayed after a crash
     */
    if (flushall) {
        flush_older_journal_lists(s, jl);
    }

    err = journal->j_errno;
    /* before we can remove everything from the hash tables for this
     ** transaction, we must make sure it can never be replayed
     **
     ** since we are only called from do_journal_end, we know for sure there
     ** are no allocations going on while we are flushing journal lists.  So,
     ** we only need to update the journal header block for the last list
     ** being flushed
     */
    if (!err && flushall) {
        err =
            update_journal_header_block(s,
                        (jl->j_start + jl->j_len +
                         2) % SB_ONDISK_JOURNAL_SIZE(s),
                        jl->j_trans_id);
        if (err)
            reiserfs_abort(s, -EIO,
                       "Write error while updating journal header in %s",
                       __func__);
    }
    remove_all_from_journal_list(s, jl, 0);
    list_del_init(&jl->j_list);
    journal->j_num_lists--;
    del_from_work_list(s, jl);

    if (journal->j_last_flush_id != 0 &&
        (jl->j_trans_id - journal->j_last_flush_id) != 1) {
        reiserfs_warning(s, "clm-2201", "last flush %lu, current %lu",
                 journal->j_last_flush_id, jl->j_trans_id);
    }
    journal->j_last_flush_id = jl->j_trans_id;

    /* not strictly required since we are freeing the list, but it should
     * help find code using dead lists later on
     */
    jl->j_len = 0;
    atomic_set(&(jl->j_nonzerolen), 0);
    jl->j_start = 0;
    jl->j_realblock = NULL;
    jl->j_commit_bh = NULL;
    jl->j_trans_id = 0;
    jl->j_state = 0;
    put_journal_list(s, jl);
    if (flushall)
        mutex_unlock(&journal->j_flush_mutex);
    return err;
}

static int test_transaction(struct super_block *s,
                            struct reiserfs_journal_list *jl)
{
    struct reiserfs_journal_cnode *cn;

    if (jl->j_len == 0 || atomic_read(&jl->j_nonzerolen) == 0)
        return 1;

    cn = jl->j_realblock;
    while (cn) {
        /* if the blocknr == 0, this has been cleared from the hash,
         ** skip it
         */
        if (cn->blocknr == 0) {
            goto next;
        }
        if (cn->bh && !newer_jl_done(cn))
            return 0;
          next:
        cn = cn->next;
        cond_resched();
    }
    return 0;
}

static int write_one_transaction(struct super_block *s,
                 struct reiserfs_journal_list *jl,
                 struct buffer_chunk *chunk)
{
    struct reiserfs_journal_cnode *cn;
    int ret = 0;

    jl->j_state |= LIST_TOUCHED;
    del_from_work_list(s, jl);
    if (jl->j_len == 0 || atomic_read(&jl->j_nonzerolen) == 0) {
        return 0;
    }

    cn = jl->j_realblock;
    while (cn) {
        /* if the blocknr == 0, this has been cleared from the hash,
         ** skip it
         */
        if (cn->blocknr == 0) {
            goto next;
        }
        if (cn->bh && can_dirty(cn) && buffer_dirty(cn->bh)) {
            struct buffer_head *tmp_bh;
            /* we can race against journal_mark_freed when we try
             * to lock_buffer(cn->bh), so we have to inc the buffer
             * count, and recheck things after locking
             */
            tmp_bh = cn->bh;
            get_bh(tmp_bh);
            lock_buffer(tmp_bh);
            if (cn->bh && can_dirty(cn) && buffer_dirty(tmp_bh)) {
                if (!buffer_journal_dirty(tmp_bh) ||
                    buffer_journal_prepared(tmp_bh))
                    BUG();
                add_to_chunk(chunk, tmp_bh, NULL, write_chunk);
                ret++;
            } else {
                /* note, cn->bh might be null now */
                unlock_buffer(tmp_bh);
            }
            put_bh(tmp_bh);
        }
          next:
        cn = cn->next;
        cond_resched();
    }
    return ret;
}

/* used by flush_commit_list */
static int dirty_one_transaction(struct super_block *s,
                 struct reiserfs_journal_list *jl)
{
    struct reiserfs_journal_cnode *cn;
    struct reiserfs_journal_list *pjl;
    int ret = 0;

    jl->j_state |= LIST_DIRTY;
    cn = jl->j_realblock;
    while (cn) {
        /* look for a more recent transaction that logged this
         ** buffer.  Only the most recent transaction with a buffer in
         ** it is allowed to send that buffer to disk
         */
        pjl = find_newer_jl_for_cn(cn);
        if (!pjl && cn->blocknr && cn->bh
            && buffer_journal_dirty(cn->bh)) {
            BUG_ON(!can_dirty(cn));
            /* if the buffer is prepared, it will either be logged
             * or restored.  If restored, we need to make sure
             * it actually gets marked dirty
             */
            clear_buffer_journal_new(cn->bh);
            if (buffer_journal_prepared(cn->bh)) {
                set_buffer_journal_restore_dirty(cn->bh);
            } else {
                set_buffer_journal_test(cn->bh);
                mark_buffer_dirty(cn->bh);
            }
        }
        cn = cn->next;
    }
    return ret;
}

static int kupdate_transactions(struct super_block *s,
                struct reiserfs_journal_list *jl,
                struct reiserfs_journal_list **next_jl,
                unsigned int *next_trans_id,
                int num_blocks, int num_trans)
{
    int ret = 0;
    int written = 0;
    int transactions_flushed = 0;
    unsigned int orig_trans_id = jl->j_trans_id;
    struct buffer_chunk chunk;
    struct list_head *entry;
    struct reiserfs_journal *journal = SB_JOURNAL(s);
    chunk.nr = 0;

    reiserfs_mutex_lock_safe(&journal->j_flush_mutex, s);
    if (!journal_list_still_alive(s, orig_trans_id)) {
        goto done;
    }

    /* we've got j_flush_mutex held, nobody is going to delete any
     * of these lists out from underneath us
     */
    while ((num_trans && transactions_flushed < num_trans) ||
           (!num_trans && written < num_blocks)) {

        if (jl->j_len == 0 || (jl->j_state & LIST_TOUCHED) ||
            atomic_read(&jl->j_commit_left)
            || !(jl->j_state & LIST_DIRTY)) {
            del_from_work_list(s, jl);
            break;
        }
        ret = write_one_transaction(s, jl, &chunk);

        if (ret < 0)
            goto done;
        transactions_flushed++;
        written += ret;
        entry = jl->j_list.next;

        /* did we wrap? */
        if (entry == &journal->j_journal_list) {
            break;
        }
        jl = JOURNAL_LIST_ENTRY(entry);

        /* don't bother with older transactions */
        if (jl->j_trans_id <= orig_trans_id)
            break;
    }
    if (chunk.nr) {
        write_chunk(&chunk);
    }

      done:
    mutex_unlock(&journal->j_flush_mutex);
    return ret;
}

/* for o_sync and fsync heavy applications, they tend to use
** all the journa list slots with tiny transactions.  These
** trigger lots and lots of calls to update the header block, which
** adds seeks and slows things down.
**
** This function tries to clear out a large chunk of the journal lists
** at once, which makes everything faster since only the newest journal
** list updates the header block
*/
static int flush_used_journal_lists(struct super_block *s,
                    struct reiserfs_journal_list *jl)
{
    unsigned long len = 0;
    unsigned long cur_len;
    int ret;
    int i;
    int limit = 256;
    struct reiserfs_journal_list *tjl;
    struct reiserfs_journal_list *flush_jl;
    unsigned int trans_id;
    struct reiserfs_journal *journal = SB_JOURNAL(s);

    flush_jl = tjl = jl;

    /* in data logging mode, try harder to flush a lot of blocks */
    if (reiserfs_data_log(s))
        limit = 1024;
    /* flush for 256 transactions or limit blocks, whichever comes first */
    for (i = 0; i < 256 && len < limit; i++) {
        if (atomic_read(&tjl->j_commit_left) ||
            tjl->j_trans_id < jl->j_trans_id) {
            break;
        }
        cur_len = atomic_read(&tjl->j_nonzerolen);
        if (cur_len > 0) {
            tjl->j_state &= ~LIST_TOUCHED;
        }
        len += cur_len;
        flush_jl = tjl;
        if (tjl->j_list.next == &journal->j_journal_list)
            break;
        tjl = JOURNAL_LIST_ENTRY(tjl->j_list.next);
    }
    /* try to find a group of blocks we can flush across all the
     ** transactions, but only bother if we've actually spanned
     ** across multiple lists
     */
    if (flush_jl != jl) {
        ret = kupdate_transactions(s, jl, &tjl, &trans_id, len, i);
    }
    flush_journal_list(s, flush_jl, 1);
    return 0;
}

/*
** removes any nodes in table with name block and dev as bh.
** only touchs the hnext and hprev pointers.
*/
void remove_journal_hash(struct super_block *sb,
             struct reiserfs_journal_cnode **table,
             struct reiserfs_journal_list *jl,
             unsigned long block, int remove_freed)
{
    struct reiserfs_journal_cnode *cur;
    struct reiserfs_journal_cnode **head;

    head = &(journal_hash(table, sb, block));
    if (!head) {
        return;
    }
    cur = *head;
    while (cur) {
        if (cur->blocknr == block && cur->sb == sb
            && (jl == NULL || jl == cur->jlist)
            && (!test_bit(BLOCK_FREED, &cur->state) || remove_freed)) {
            if (cur->hnext) {
                cur->hnext->hprev = cur->hprev;
            }
            if (cur->hprev) {
                cur->hprev->hnext = cur->hnext;
            } else {
                *head = cur->hnext;
            }
            cur->blocknr = 0;
            cur->sb = NULL;
            cur->state = 0;
            if (cur->bh && cur->jlist)  /* anybody who clears the cur->bh will also dec the nonzerolen */
                atomic_dec(&(cur->jlist->j_nonzerolen));
            cur->bh = NULL;
            cur->jlist = NULL;
        }
        cur = cur->hnext;
    }
}

static void free_journal_ram(struct super_block *sb)
{
    struct reiserfs_journal *journal = SB_JOURNAL(sb);
    kfree(journal->j_current_jl);
    journal->j_num_lists--;

    vfree(journal->j_cnode_free_orig);
    free_list_bitmaps(sb, journal->j_list_bitmap);
    free_bitmap_nodes(sb);  /* must be after free_list_bitmaps */
    if (journal->j_header_bh) {
        brelse(journal->j_header_bh);
    }
    /* j_header_bh is on the journal dev, make sure not to release the journal
     * dev until we brelse j_header_bh
     */
    release_journal_dev(sb, journal);
    vfree(journal);
}

/*
** call on unmount.  Only set error to 1 if you haven't made your way out
** of read_super() yet.  Any other caller must keep error at 0.
*/
static int do_journal_release(struct reiserfs_transaction_handle *th,
                  struct super_block *sb, int error)
{
    struct reiserfs_transaction_handle myth;
    int flushed = 0;
    struct reiserfs_journal *journal = SB_JOURNAL(sb);

    /* we only want to flush out transactions if we were called with error == 0
     */
    if (!error && !(sb->s_flags & MS_RDONLY)) {
        /* end the current trans */
        BUG_ON(!th->t_trans_id);
        do_journal_end(th, sb, 10, FLUSH_ALL);

        /* make sure something gets logged to force our way into the flush code */
        if (!journal_join(&myth, sb, 1)) {
            reiserfs_prepare_for_journal(sb,
                             SB_BUFFER_WITH_SB(sb),
                             1);
            journal_mark_dirty(&myth, sb,
                       SB_BUFFER_WITH_SB(sb));
            do_journal_end(&myth, sb, 1, FLUSH_ALL);
            flushed = 1;
        }
    }

    /* this also catches errors during the do_journal_end above */
    if (!error && reiserfs_is_journal_aborted(journal)) {
        memset(&myth, 0, sizeof(myth));
        if (!journal_join_abort(&myth, sb, 1)) {
            reiserfs_prepare_for_journal(sb,
                             SB_BUFFER_WITH_SB(sb),
                             1);
            journal_mark_dirty(&myth, sb,
                       SB_BUFFER_WITH_SB(sb));
            do_journal_end(&myth, sb, 1, FLUSH_ALL);
        }
    }

    reiserfs_mounted_fs_count--;
    /* wait for all commits to finish */
    cancel_delayed_work(&SB_JOURNAL(sb)->j_work);

    /*
     * We must release the write lock here because
     * the workqueue job (flush_async_commit) needs this lock
     */
    reiserfs_write_unlock(sb);

    cancel_delayed_work_sync(&REISERFS_SB(sb)->old_work);
    flush_workqueue(commit_wq);

    if (!reiserfs_mounted_fs_count) {
        destroy_workqueue(commit_wq);
        commit_wq = NULL;
    }

    free_journal_ram(sb);

    reiserfs_write_lock(sb);

    return 0;
}

/*
** call on unmount.  flush all journal trans, release all alloc'd ram
*/
int journal_release(struct reiserfs_transaction_handle *th,
            struct super_block *sb)
{
    return do_journal_release(th, sb, 0);
}

/*
** only call from an error condition inside reiserfs_read_super!
*/
int journal_release_error(struct reiserfs_transaction_handle *th,
              struct super_block *sb)
{
    return do_journal_release(th, sb, 1);
}

/* compares description block with commit block.  returns 1 if they differ, 0 if they are the same */
static int journal_compare_desc_commit(struct super_block *sb,
                       struct reiserfs_journal_desc *desc,
                       struct reiserfs_journal_commit *commit)
{
    if (get_commit_trans_id(commit) != get_desc_trans_id(desc) ||
        get_commit_trans_len(commit) != get_desc_trans_len(desc) ||
        get_commit_trans_len(commit) > SB_JOURNAL(sb)->j_trans_max ||
        get_commit_trans_len(commit) <= 0) {
        return 1;
    }
    return 0;
}

/* returns 0 if it did not find a description block
** returns -1 if it found a corrupt commit block
** returns 1 if both desc and commit were valid
*/
static int journal_transaction_is_valid(struct super_block *sb,
                    struct buffer_head *d_bh,
                    unsigned int *oldest_invalid_trans_id,
                    unsigned long *newest_mount_id)
{
    struct reiserfs_journal_desc *desc;
    struct reiserfs_journal_commit *commit;
    struct buffer_head *c_bh;
    unsigned long offset;

    if (!d_bh)
        return 0;

    desc = (struct reiserfs_journal_desc *)d_bh->b_data;
    if (get_desc_trans_len(desc) > 0
        && !memcmp(get_journal_desc_magic(d_bh), JOURNAL_DESC_MAGIC, 8)) {
        if (oldest_invalid_trans_id && *oldest_invalid_trans_id
            && get_desc_trans_id(desc) > *oldest_invalid_trans_id) {
            reiserfs_debug(sb, REISERFS_DEBUG_CODE,
                       "journal-986: transaction "
                       "is valid returning because trans_id %d is greater than "
                       "oldest_invalid %lu",
                       get_desc_trans_id(desc),
                       *oldest_invalid_trans_id);
            return 0;
        }
        if (newest_mount_id
            && *newest_mount_id > get_desc_mount_id(desc)) {
            reiserfs_debug(sb, REISERFS_DEBUG_CODE,
                       "journal-1087: transaction "
                       "is valid returning because mount_id %d is less than "
                       "newest_mount_id %lu",
                       get_desc_mount_id(desc),
                       *newest_mount_id);
            return -1;
        }
        if (get_desc_trans_len(desc) > SB_JOURNAL(sb)->j_trans_max) {
            reiserfs_warning(sb, "journal-2018",
                     "Bad transaction length %d "
                     "encountered, ignoring transaction",
                     get_desc_trans_len(desc));
            return -1;
        }
        offset = d_bh->b_blocknr - SB_ONDISK_JOURNAL_1st_BLOCK(sb);

        /* ok, we have a journal description block, lets see if the transaction was valid */
        c_bh =
            journal_bread(sb,
                  SB_ONDISK_JOURNAL_1st_BLOCK(sb) +
                  ((offset + get_desc_trans_len(desc) +
                    1) % SB_ONDISK_JOURNAL_SIZE(sb)));
        if (!c_bh)
            return 0;
        commit = (struct reiserfs_journal_commit *)c_bh->b_data;
        if (journal_compare_desc_commit(sb, desc, commit)) {
            reiserfs_debug(sb, REISERFS_DEBUG_CODE,
                       "journal_transaction_is_valid, commit offset %ld had bad "
                       "time %d or length %d",
                       c_bh->b_blocknr -
                       SB_ONDISK_JOURNAL_1st_BLOCK(sb),
                       get_commit_trans_id(commit),
                       get_commit_trans_len(commit));
            brelse(c_bh);
            if (oldest_invalid_trans_id) {
                *oldest_invalid_trans_id =
                    get_desc_trans_id(desc);
                reiserfs_debug(sb, REISERFS_DEBUG_CODE,
                           "journal-1004: "
                           "transaction_is_valid setting oldest invalid trans_id "
                           "to %d",
                           get_desc_trans_id(desc));
            }
            return -1;
        }
        brelse(c_bh);
        reiserfs_debug(sb, REISERFS_DEBUG_CODE,
                   "journal-1006: found valid "
                   "transaction start offset %llu, len %d id %d",
                   d_bh->b_blocknr -
                   SB_ONDISK_JOURNAL_1st_BLOCK(sb),
                   get_desc_trans_len(desc),
                   get_desc_trans_id(desc));
        return 1;
    } else {
        return 0;
    }
}

static void brelse_array(struct buffer_head **heads, int num)
{
    int i;
    for (i = 0; i < num; i++) {
        brelse(heads[i]);
    }
}

/*
** given the start, and values for the oldest acceptable transactions,
** this either reads in a replays a transaction, or returns because the transaction
** is invalid, or too old.
*/
static int journal_read_transaction(struct super_block *sb,
                    unsigned long cur_dblock,
                    unsigned long oldest_start,
                    unsigned int oldest_trans_id,
                    unsigned long newest_mount_id)
{
    struct reiserfs_journal *journal = SB_JOURNAL(sb);
    struct reiserfs_journal_desc *desc;
    struct reiserfs_journal_commit *commit;
    unsigned int trans_id = 0;
    struct buffer_head *c_bh;
    struct buffer_head *d_bh;
    struct buffer_head **log_blocks = NULL;
    struct buffer_head **real_blocks = NULL;
    unsigned int trans_offset;
    int i;
    int trans_half;

    d_bh = journal_bread(sb, cur_dblock);
    if (!d_bh)
        return 1;
    desc = (struct reiserfs_journal_desc *)d_bh->b_data;
    trans_offset = d_bh->b_blocknr - SB_ONDISK_JOURNAL_1st_BLOCK(sb);
    reiserfs_debug(sb, REISERFS_DEBUG_CODE, "journal-1037: "
               "journal_read_transaction, offset %llu, len %d mount_id %d",
               d_bh->b_blocknr - SB_ONDISK_JOURNAL_1st_BLOCK(sb),
               get_desc_trans_len(desc), get_desc_mount_id(desc));
    if (get_desc_trans_id(desc) < oldest_trans_id) {
        reiserfs_debug(sb, REISERFS_DEBUG_CODE, "journal-1039: "
                   "journal_read_trans skipping because %lu is too old",
                   cur_dblock -
                   SB_ONDISK_JOURNAL_1st_BLOCK(sb));
        brelse(d_bh);
        return 1;
    }
    if (get_desc_mount_id(desc) != newest_mount_id) {
        reiserfs_debug(sb, REISERFS_DEBUG_CODE, "journal-1146: "
                   "journal_read_trans skipping because %d is != "
                   "newest_mount_id %lu", get_desc_mount_id(desc),
                   newest_mount_id);
        brelse(d_bh);
        return 1;
    }
    c_bh = journal_bread(sb, SB_ONDISK_JOURNAL_1st_BLOCK(sb) +
                 ((trans_offset + get_desc_trans_len(desc) + 1) %
                  SB_ONDISK_JOURNAL_SIZE(sb)));
    if (!c_bh) {
        brelse(d_bh);
        return 1;
    }
    commit = (struct reiserfs_journal_commit *)c_bh->b_data;
    if (journal_compare_desc_commit(sb, desc, commit)) {
        reiserfs_debug(sb, REISERFS_DEBUG_CODE,
                   "journal_read_transaction, "
                   "commit offset %llu had bad time %d or length %d",
                   c_bh->b_blocknr -
                   SB_ONDISK_JOURNAL_1st_BLOCK(sb),
                   get_commit_trans_id(commit),
                   get_commit_trans_len(commit));
        brelse(c_bh);
        brelse(d_bh);
        return 1;
    }

    if (bdev_read_only(sb->s_bdev)) {
        reiserfs_warning(sb, "clm-2076",
                 "device is readonly, unable to replay log");
        brelse(c_bh);
        brelse(d_bh);
        return -EROFS;
    }

    trans_id = get_desc_trans_id(desc);
    /* now we know we've got a good transaction, and it was inside the valid time ranges */
    log_blocks = kmalloc(get_desc_trans_len(desc) *
                 sizeof(struct buffer_head *), GFP_NOFS);
    real_blocks = kmalloc(get_desc_trans_len(desc) *
                  sizeof(struct buffer_head *), GFP_NOFS);
    if (!log_blocks || !real_blocks) {
        brelse(c_bh);
        brelse(d_bh);
        kfree(log_blocks);
        kfree(real_blocks);
        reiserfs_warning(sb, "journal-1169",
                 "kmalloc failed, unable to mount FS");
        return -1;
    }
    /* get all the buffer heads */
    trans_half = journal_trans_half(sb->s_blocksize);
    for (i = 0; i < get_desc_trans_len(desc); i++) {
        log_blocks[i] =
            journal_getblk(sb,
                   SB_ONDISK_JOURNAL_1st_BLOCK(sb) +
                   (trans_offset + 1 +
                    i) % SB_ONDISK_JOURNAL_SIZE(sb));
        if (i < trans_half) {
            real_blocks[i] =
                sb_getblk(sb,
                      le32_to_cpu(desc->j_realblock[i]));
        } else {
            real_blocks[i] =
                sb_getblk(sb,
                      le32_to_cpu(commit->
                          j_realblock[i - trans_half]));
        }
        if (real_blocks[i]->b_blocknr > SB_BLOCK_COUNT(sb)) {
            reiserfs_warning(sb, "journal-1207",
                     "REPLAY FAILURE fsck required! "
                     "Block to replay is outside of "
                     "filesystem");
            goto abort_replay;
        }
        /* make sure we don't try to replay onto log or reserved area */
        if (is_block_in_log_or_reserved_area
            (sb, real_blocks[i]->b_blocknr)) {
            reiserfs_warning(sb, "journal-1204",
                     "REPLAY FAILURE fsck required! "
                     "Trying to replay onto a log block");
              abort_replay:
            brelse_array(log_blocks, i);
            brelse_array(real_blocks, i);
            brelse(c_bh);
            brelse(d_bh);
            kfree(log_blocks);
            kfree(real_blocks);
            return -1;
        }
    }
    /* read in the log blocks, memcpy to the corresponding real block */
    ll_rw_block(READ, get_desc_trans_len(desc), log_blocks);
    for (i = 0; i < get_desc_trans_len(desc); i++) {

        reiserfs_write_unlock(sb);
        wait_on_buffer(log_blocks[i]);
        reiserfs_write_lock(sb);

        if (!buffer_uptodate(log_blocks[i])) {
            reiserfs_warning(sb, "journal-1212",
                     "REPLAY FAILURE fsck required! "
                     "buffer write failed");
            brelse_array(log_blocks + i,
                     get_desc_trans_len(desc) - i);
            brelse_array(real_blocks, get_desc_trans_len(desc));
            brelse(c_bh);
            brelse(d_bh);
            kfree(log_blocks);
            kfree(real_blocks);
            return -1;
        }
        memcpy(real_blocks[i]->b_data, log_blocks[i]->b_data,
               real_blocks[i]->b_size);
        set_buffer_uptodate(real_blocks[i]);
        brelse(log_blocks[i]);
    }
    /* flush out the real blocks */
    for (i = 0; i < get_desc_trans_len(desc); i++) {
        set_buffer_dirty(real_blocks[i]);
        write_dirty_buffer(real_blocks[i], WRITE);
    }
    for (i = 0; i < get_desc_trans_len(desc); i++) {
        wait_on_buffer(real_blocks[i]);
        if (!buffer_uptodate(real_blocks[i])) {
            reiserfs_warning(sb, "journal-1226",
                     "REPLAY FAILURE, fsck required! "
                     "buffer write failed");
            brelse_array(real_blocks + i,
                     get_desc_trans_len(desc) - i);
            brelse(c_bh);
            brelse(d_bh);
            kfree(log_blocks);
            kfree(real_blocks);
            return -1;
        }
        brelse(real_blocks[i]);
    }
    cur_dblock =
        SB_ONDISK_JOURNAL_1st_BLOCK(sb) +
        ((trans_offset + get_desc_trans_len(desc) +
          2) % SB_ONDISK_JOURNAL_SIZE(sb));
    reiserfs_debug(sb, REISERFS_DEBUG_CODE,
               "journal-1095: setting journal " "start to offset %ld",
               cur_dblock - SB_ONDISK_JOURNAL_1st_BLOCK(sb));

    /* init starting values for the first transaction, in case this is the last transaction to be replayed. */
    journal->j_start = cur_dblock - SB_ONDISK_JOURNAL_1st_BLOCK(sb);
    journal->j_last_flush_trans_id = trans_id;
    journal->j_trans_id = trans_id + 1;
    /* check for trans_id overflow */
    if (journal->j_trans_id == 0)
        journal->j_trans_id = 10;
    brelse(c_bh);
    brelse(d_bh);
    kfree(log_blocks);
    kfree(real_blocks);
    return 0;
}

/* This function reads blocks starting from block and to max_block of bufsize
   size (but no more than BUFNR blocks at a time). This proved to improve
   mounting speed on self-rebuilding raid5 arrays at least.
   Right now it is only used from journal code. But later we might use it
   from other places.
   Note: Do not use journal_getblk/sb_getblk functions here! */
static struct buffer_head *reiserfs_breada(struct block_device *dev,
                       b_blocknr_t block, int bufsize,
                       b_blocknr_t max_block)
{
    struct buffer_head *bhlist[BUFNR];
    unsigned int blocks = BUFNR;
    struct buffer_head *bh;
    int i, j;

    bh = __getblk(dev, block, bufsize);
    if (buffer_uptodate(bh))
        return (bh);

    if (block + BUFNR > max_block) {
        blocks = max_block - block;
    }
    bhlist[0] = bh;
    j = 1;
    for (i = 1; i < blocks; i++) {
        bh = __getblk(dev, block + i, bufsize);
        if (buffer_uptodate(bh)) {
            brelse(bh);
            break;
        } else
            bhlist[j++] = bh;
    }
    ll_rw_block(READ, j, bhlist);
    for (i = 1; i < j; i++)
        brelse(bhlist[i]);
    bh = bhlist[0];
    wait_on_buffer(bh);
    if (buffer_uptodate(bh))
        return bh;
    brelse(bh);
    return NULL;
}

/*
** read and replay the log
** on a clean unmount, the journal header's next unflushed pointer will be to an invalid
** transaction.  This tests that before finding all the transactions in the log, which makes normal mount times fast.
**
** After a crash, this starts with the next unflushed transaction, and replays until it finds one too old, or invalid.
**
** On exit, it sets things up so the first transaction will work correctly.
*/
static int journal_read(struct super_block *sb)
{
    struct reiserfs_journal *journal = SB_JOURNAL(sb);
    struct reiserfs_journal_desc *desc;
    unsigned int oldest_trans_id = 0;
    unsigned int oldest_invalid_trans_id = 0;
    time_t start;
    unsigned long oldest_start = 0;
    unsigned long cur_dblock = 0;
    unsigned long newest_mount_id = 9;
    struct buffer_head *d_bh;
    struct reiserfs_journal_header *jh;
    int valid_journal_header = 0;
    int replay_count = 0;
    int continue_replay = 1;
    int ret;
    char b[BDEVNAME_SIZE];

    cur_dblock = SB_ONDISK_JOURNAL_1st_BLOCK(sb);
    reiserfs_info(sb, "checking transaction log (%s)\n",
              bdevname(journal->j_dev_bd, b));
    start = get_seconds();

    /* step 1, read in the journal header block.  Check the transaction it says
     ** is the first unflushed, and if that transaction is not valid,
     ** replay is done
     */
    journal->j_header_bh = journal_bread(sb,
                         SB_ONDISK_JOURNAL_1st_BLOCK(sb)
                         + SB_ONDISK_JOURNAL_SIZE(sb));
    if (!journal->j_header_bh) {
        return 1;
    }
    jh = (struct reiserfs_journal_header *)(journal->j_header_bh->b_data);
    if (le32_to_cpu(jh->j_first_unflushed_offset) <
        SB_ONDISK_JOURNAL_SIZE(sb)
        && le32_to_cpu(jh->j_last_flush_trans_id) > 0) {
        oldest_start =
            SB_ONDISK_JOURNAL_1st_BLOCK(sb) +
            le32_to_cpu(jh->j_first_unflushed_offset);
        oldest_trans_id = le32_to_cpu(jh->j_last_flush_trans_id) + 1;
        newest_mount_id = le32_to_cpu(jh->j_mount_id);
        reiserfs_debug(sb, REISERFS_DEBUG_CODE,
                   "journal-1153: found in "
                   "header: first_unflushed_offset %d, last_flushed_trans_id "
                   "%lu", le32_to_cpu(jh->j_first_unflushed_offset),
                   le32_to_cpu(jh->j_last_flush_trans_id));
        valid_journal_header = 1;

        /* now, we try to read the first unflushed offset.  If it is not valid,
         ** there is nothing more we can do, and it makes no sense to read
         ** through the whole log.
         */
        d_bh =
            journal_bread(sb,
                  SB_ONDISK_JOURNAL_1st_BLOCK(sb) +
                  le32_to_cpu(jh->j_first_unflushed_offset));
        ret = journal_transaction_is_valid(sb, d_bh, NULL, NULL);
        if (!ret) {
            continue_replay = 0;
        }
        brelse(d_bh);
        goto start_log_replay;
    }

    /* ok, there are transactions that need to be replayed.  start with the first log block, find
     ** all the valid transactions, and pick out the oldest.
     */
    while (continue_replay
           && cur_dblock <
           (SB_ONDISK_JOURNAL_1st_BLOCK(sb) +
        SB_ONDISK_JOURNAL_SIZE(sb))) {
        /* Note that it is required for blocksize of primary fs device and journal
           device to be the same */
        d_bh =
            reiserfs_breada(journal->j_dev_bd, cur_dblock,
                    sb->s_blocksize,
                    SB_ONDISK_JOURNAL_1st_BLOCK(sb) +
                    SB_ONDISK_JOURNAL_SIZE(sb));
        ret =
            journal_transaction_is_valid(sb, d_bh,
                         &oldest_invalid_trans_id,
                         &newest_mount_id);
        if (ret == 1) {
            desc = (struct reiserfs_journal_desc *)d_bh->b_data;
            if (oldest_start == 0) {    /* init all oldest_ values */
                oldest_trans_id = get_desc_trans_id(desc);
                oldest_start = d_bh->b_blocknr;
                newest_mount_id = get_desc_mount_id(desc);
                reiserfs_debug(sb, REISERFS_DEBUG_CODE,
                           "journal-1179: Setting "
                           "oldest_start to offset %llu, trans_id %lu",
                           oldest_start -
                           SB_ONDISK_JOURNAL_1st_BLOCK
                           (sb), oldest_trans_id);
            } else if (oldest_trans_id > get_desc_trans_id(desc)) {
                /* one we just read was older */
                oldest_trans_id = get_desc_trans_id(desc);
                oldest_start = d_bh->b_blocknr;
                reiserfs_debug(sb, REISERFS_DEBUG_CODE,
                           "journal-1180: Resetting "
                           "oldest_start to offset %lu, trans_id %lu",
                           oldest_start -
                           SB_ONDISK_JOURNAL_1st_BLOCK
                           (sb), oldest_trans_id);
            }
            if (newest_mount_id < get_desc_mount_id(desc)) {
                newest_mount_id = get_desc_mount_id(desc);
                reiserfs_debug(sb, REISERFS_DEBUG_CODE,
                           "journal-1299: Setting "
                           "newest_mount_id to %d",
                           get_desc_mount_id(desc));
            }
            cur_dblock += get_desc_trans_len(desc) + 2;
        } else {
            cur_dblock++;
        }
        brelse(d_bh);
    }

      start_log_replay:
    cur_dblock = oldest_start;
    if (oldest_trans_id) {
        reiserfs_debug(sb, REISERFS_DEBUG_CODE,
                   "journal-1206: Starting replay "
                   "from offset %llu, trans_id %lu",
                   cur_dblock - SB_ONDISK_JOURNAL_1st_BLOCK(sb),
                   oldest_trans_id);

    }
    replay_count = 0;
    while (continue_replay && oldest_trans_id > 0) {
        ret =
            journal_read_transaction(sb, cur_dblock, oldest_start,
                         oldest_trans_id, newest_mount_id);
        if (ret < 0) {
            return ret;
        } else if (ret != 0) {
            break;
        }
        cur_dblock =
            SB_ONDISK_JOURNAL_1st_BLOCK(sb) + journal->j_start;
        replay_count++;
        if (cur_dblock == oldest_start)
            break;
    }

    if (oldest_trans_id == 0) {
        reiserfs_debug(sb, REISERFS_DEBUG_CODE,
                   "journal-1225: No valid " "transactions found");
    }
    /* j_start does not get set correctly if we don't replay any transactions.
     ** if we had a valid journal_header, set j_start to the first unflushed transaction value,
     ** copy the trans_id from the header
     */
    if (valid_journal_header && replay_count == 0) {
        journal->j_start = le32_to_cpu(jh->j_first_unflushed_offset);
        journal->j_trans_id =
            le32_to_cpu(jh->j_last_flush_trans_id) + 1;
        /* check for trans_id overflow */
        if (journal->j_trans_id == 0)
            journal->j_trans_id = 10;
        journal->j_last_flush_trans_id =
            le32_to_cpu(jh->j_last_flush_trans_id);
        journal->j_mount_id = le32_to_cpu(jh->j_mount_id) + 1;
    } else {
        journal->j_mount_id = newest_mount_id + 1;
    }
    reiserfs_debug(sb, REISERFS_DEBUG_CODE, "journal-1299: Setting "
               "newest_mount_id to %lu", journal->j_mount_id);
    journal->j_first_unflushed_offset = journal->j_start;
    if (replay_count > 0) {
        reiserfs_info(sb,
                  "replayed %d transactions in %lu seconds\n",
                  replay_count, get_seconds() - start);
    }
    if (!bdev_read_only(sb->s_bdev) &&
        _update_journal_header_block(sb, journal->j_start,
                     journal->j_last_flush_trans_id)) {
        /* replay failed, caller must call free_journal_ram and abort
         ** the mount
         */
        return -1;
    }
    return 0;
}

static struct reiserfs_journal_list *alloc_journal_list(struct super_block *s)
{
    struct reiserfs_journal_list *jl;
    jl = kzalloc(sizeof(struct reiserfs_journal_list),
             GFP_NOFS | __GFP_NOFAIL);
    INIT_LIST_HEAD(&jl->j_list);
    INIT_LIST_HEAD(&jl->j_working_list);
    INIT_LIST_HEAD(&jl->j_tail_bh_list);
    INIT_LIST_HEAD(&jl->j_bh_list);
    mutex_init(&jl->j_commit_mutex);
    SB_JOURNAL(s)->j_num_lists++;
    get_journal_list(jl);
    return jl;
}

static void journal_list_init(struct super_block *sb)
{
    SB_JOURNAL(sb)->j_current_jl = alloc_journal_list(sb);
}

static int release_journal_dev(struct super_block *super,
                   struct reiserfs_journal *journal)
{
    int result;

    result = 0;

    if (journal->j_dev_bd != NULL) {
        result = blkdev_put(journal->j_dev_bd, journal->j_dev_mode);
        journal->j_dev_bd = NULL;
    }

    if (result != 0) {
        reiserfs_warning(super, "sh-457",
                 "Cannot release journal device: %i", result);
    }
    return result;
}

static int journal_init_dev(struct super_block *super,
                struct reiserfs_journal *journal,
                const char *jdev_name)
{
    int result;
    dev_t jdev;
    fmode_t blkdev_mode = FMODE_READ | FMODE_WRITE | FMODE_EXCL;
    char b[BDEVNAME_SIZE];

    result = 0;

    journal->j_dev_bd = NULL;
    jdev = SB_ONDISK_JOURNAL_DEVICE(super) ?
        new_decode_dev(SB_ONDISK_JOURNAL_DEVICE(super)) : super->s_dev;

    if (bdev_read_only(super->s_bdev))
        blkdev_mode = FMODE_READ;

    /* there is no "jdev" option and journal is on separate device */
    if ((!jdev_name || !jdev_name[0])) {
        if (jdev == super->s_dev)
            blkdev_mode &= ~FMODE_EXCL;
        journal->j_dev_bd = blkdev_get_by_dev(jdev, blkdev_mode,
                              journal);
        journal->j_dev_mode = blkdev_mode;
        if (IS_ERR(journal->j_dev_bd)) {
            result = PTR_ERR(journal->j_dev_bd);
            journal->j_dev_bd = NULL;
            reiserfs_warning(super, "sh-458",
                     "cannot init journal device '%s': %i",
                     __bdevname(jdev, b), result);
            return result;
        } else if (jdev != super->s_dev)
            set_blocksize(journal->j_dev_bd, super->s_blocksize);

        return 0;
    }

    journal->j_dev_mode = blkdev_mode;
    journal->j_dev_bd = blkdev_get_by_path(jdev_name, blkdev_mode, journal);
    if (IS_ERR(journal->j_dev_bd)) {
        result = PTR_ERR(journal->j_dev_bd);
        journal->j_dev_bd = NULL;
        reiserfs_warning(super,
                 "journal_init_dev: Cannot open '%s': %i",
                 jdev_name, result);
        return result;
    }

    set_blocksize(journal->j_dev_bd, super->s_blocksize);
    reiserfs_info(super,
              "journal_init_dev: journal device: %s\n",
              bdevname(journal->j_dev_bd, b));
    return 0;
}

#define REISERFS_STANDARD_BLKSIZE (4096)

static int check_advise_trans_params(struct super_block *sb,
                     struct reiserfs_journal *journal)
{
        if (journal->j_trans_max) {
            /* Non-default journal params.
           Do sanity check for them. */
            int ratio = 1;
        if (sb->s_blocksize < REISERFS_STANDARD_BLKSIZE)
                ratio = REISERFS_STANDARD_BLKSIZE / sb->s_blocksize;

        if (journal->j_trans_max > JOURNAL_TRANS_MAX_DEFAULT / ratio ||
            journal->j_trans_max < JOURNAL_TRANS_MIN_DEFAULT / ratio ||
            SB_ONDISK_JOURNAL_SIZE(sb) / journal->j_trans_max <
            JOURNAL_MIN_RATIO) {
            reiserfs_warning(sb, "sh-462",
                     "bad transaction max size (%u). "
                     "FSCK?", journal->j_trans_max);
            return 1;
        }
        if (journal->j_max_batch != (journal->j_trans_max) *
                JOURNAL_MAX_BATCH_DEFAULT/JOURNAL_TRANS_MAX_DEFAULT) {
            reiserfs_warning(sb, "sh-463",
                     "bad transaction max batch (%u). "
                     "FSCK?", journal->j_max_batch);
            return 1;
        }
    } else {
        /* Default journal params.
                   The file system was created by old version
           of mkreiserfs, so some fields contain zeros,
           and we need to advise proper values for them */
        if (sb->s_blocksize != REISERFS_STANDARD_BLKSIZE) {
            reiserfs_warning(sb, "sh-464", "bad blocksize (%u)",
                     sb->s_blocksize);
            return 1;
        }
        journal->j_trans_max = JOURNAL_TRANS_MAX_DEFAULT;
        journal->j_max_batch = JOURNAL_MAX_BATCH_DEFAULT;
        journal->j_max_commit_age = JOURNAL_MAX_COMMIT_AGE;
    }
    return 0;
}

/*
** must be called once on fs mount.  calls journal_read for you
*/
int journal_init(struct super_block *sb, const char *j_dev_name,
         int old_format, unsigned int commit_max_age)
{
    int num_cnodes = SB_ONDISK_JOURNAL_SIZE(sb) * 2;
    struct buffer_head *bhjh;
    struct reiserfs_super_block *rs;
    struct reiserfs_journal_header *jh;
    struct reiserfs_journal *journal;
    struct reiserfs_journal_list *jl;
    char b[BDEVNAME_SIZE];
    int ret;

    journal = SB_JOURNAL(sb) = vzalloc(sizeof(struct reiserfs_journal));
    if (!journal) {
        reiserfs_warning(sb, "journal-1256",
                 "unable to get memory for journal structure");
        return 1;
    }
    INIT_LIST_HEAD(&journal->j_bitmap_nodes);
    INIT_LIST_HEAD(&journal->j_prealloc_list);
    INIT_LIST_HEAD(&journal->j_working_list);
    INIT_LIST_HEAD(&journal->j_journal_list);
    journal->j_persistent_trans = 0;
    if (reiserfs_allocate_list_bitmaps(sb, journal->j_list_bitmap,
                       reiserfs_bmap_count(sb)))
        goto free_and_return;

    allocate_bitmap_nodes(sb);

    /* reserved for journal area support */
    SB_JOURNAL_1st_RESERVED_BLOCK(sb) = (old_format ?
                         REISERFS_OLD_DISK_OFFSET_IN_BYTES
                         / sb->s_blocksize +
                         reiserfs_bmap_count(sb) +
                         1 :
                         REISERFS_DISK_OFFSET_IN_BYTES /
                         sb->s_blocksize + 2);

    /* Sanity check to see is the standard journal fitting within first bitmap
       (actual for small blocksizes) */
    if (!SB_ONDISK_JOURNAL_DEVICE(sb) &&
        (SB_JOURNAL_1st_RESERVED_BLOCK(sb) +
         SB_ONDISK_JOURNAL_SIZE(sb) > sb->s_blocksize * 8)) {
        reiserfs_warning(sb, "journal-1393",
                 "journal does not fit for area addressed "
                 "by first of bitmap blocks. It starts at "
                 "%u and its size is %u. Block size %ld",
                 SB_JOURNAL_1st_RESERVED_BLOCK(sb),
                 SB_ONDISK_JOURNAL_SIZE(sb),
                 sb->s_blocksize);
        goto free_and_return;
    }

    if (journal_init_dev(sb, journal, j_dev_name) != 0) {
        reiserfs_warning(sb, "sh-462",
                 "unable to initialize jornal device");
        goto free_and_return;
    }

    rs = SB_DISK_SUPER_BLOCK(sb);

    /* read journal header */
    bhjh = journal_bread(sb,
                 SB_ONDISK_JOURNAL_1st_BLOCK(sb) +
                 SB_ONDISK_JOURNAL_SIZE(sb));
    if (!bhjh) {
        reiserfs_warning(sb, "sh-459",
                 "unable to read journal header");
        goto free_and_return;
    }
    jh = (struct reiserfs_journal_header *)(bhjh->b_data);

    /* make sure that journal matches to the super block */
    if (is_reiserfs_jr(rs)
        && (le32_to_cpu(jh->jh_journal.jp_journal_magic) !=
        sb_jp_journal_magic(rs))) {
        reiserfs_warning(sb, "sh-460",
                 "journal header magic %x (device %s) does "
                 "not match to magic found in super block %x",
                 jh->jh_journal.jp_journal_magic,
                 bdevname(journal->j_dev_bd, b),
                 sb_jp_journal_magic(rs));
        brelse(bhjh);
        goto free_and_return;
    }

    journal->j_trans_max = le32_to_cpu(jh->jh_journal.jp_journal_trans_max);
    journal->j_max_batch = le32_to_cpu(jh->jh_journal.jp_journal_max_batch);
    journal->j_max_commit_age =
        le32_to_cpu(jh->jh_journal.jp_journal_max_commit_age);
    journal->j_max_trans_age = JOURNAL_MAX_TRANS_AGE;

    if (check_advise_trans_params(sb, journal) != 0)
            goto free_and_return;
    journal->j_default_max_commit_age = journal->j_max_commit_age;

    if (commit_max_age != 0) {
        journal->j_max_commit_age = commit_max_age;
        journal->j_max_trans_age = commit_max_age;
    }

    reiserfs_info(sb, "journal params: device %s, size %u, "
              "journal first block %u, max trans len %u, max batch %u, "
              "max commit age %u, max trans age %u\n",
              bdevname(journal->j_dev_bd, b),
              SB_ONDISK_JOURNAL_SIZE(sb),
              SB_ONDISK_JOURNAL_1st_BLOCK(sb),
              journal->j_trans_max,
              journal->j_max_batch,
              journal->j_max_commit_age, journal->j_max_trans_age);

    brelse(bhjh);

    journal->j_list_bitmap_index = 0;
    journal_list_init(sb);

    memset(journal->j_list_hash_table, 0,
           JOURNAL_HASH_SIZE * sizeof(struct reiserfs_journal_cnode *));

    INIT_LIST_HEAD(&journal->j_dirty_buffers);
    spin_lock_init(&journal->j_dirty_buffers_lock);

    journal->j_start = 0;
    journal->j_len = 0;
    journal->j_len_alloc = 0;
    atomic_set(&(journal->j_wcount), 0);
    atomic_set(&(journal->j_async_throttle), 0);
    journal->j_bcount = 0;
    journal->j_trans_start_time = 0;
    journal->j_last = NULL;
    journal->j_first = NULL;
    init_waitqueue_head(&(journal->j_join_wait));
    mutex_init(&journal->j_mutex);
    mutex_init(&journal->j_flush_mutex);

    journal->j_trans_id = 10;
    journal->j_mount_id = 10;
    journal->j_state = 0;
    atomic_set(&(journal->j_jlock), 0);
    journal->j_cnode_free_list = allocate_cnodes(num_cnodes);
    journal->j_cnode_free_orig = journal->j_cnode_free_list;
    journal->j_cnode_free = journal->j_cnode_free_list ? num_cnodes : 0;
    journal->j_cnode_used = 0;
    journal->j_must_wait = 0;

    if (journal->j_cnode_free == 0) {
        reiserfs_warning(sb, "journal-2004", "Journal cnode memory "
                         "allocation failed (%ld bytes). Journal is "
                         "too large for available memory. Usually "
                         "this is due to a journal that is too large.",
                         sizeof (struct reiserfs_journal_cnode) * num_cnodes);
            goto free_and_return;
    }

    init_journal_hash(sb);
    jl = journal->j_current_jl;

    /*
     * get_list_bitmap() may call flush_commit_list() which
     * requires the lock. Calling flush_commit_list() shouldn't happen
     * this early but I like to be paranoid.
     */
    reiserfs_write_lock(sb);
    jl->j_list_bitmap = get_list_bitmap(sb, jl);
    reiserfs_write_unlock(sb);
    if (!jl->j_list_bitmap) {
        reiserfs_warning(sb, "journal-2005",
                 "get_list_bitmap failed for journal list 0");
        goto free_and_return;
    }

    /*
     * Journal_read needs to be inspected in order to push down
     * the lock further inside (or even remove it).
     */
    reiserfs_write_lock(sb);
    ret = journal_read(sb);
    reiserfs_write_unlock(sb);
    if (ret < 0) {
        reiserfs_warning(sb, "reiserfs-2006",
                 "Replay Failure, unable to mount");
        goto free_and_return;
    }

    reiserfs_mounted_fs_count++;
    if (reiserfs_mounted_fs_count <= 1)
        commit_wq = alloc_workqueue("reiserfs", WQ_MEM_RECLAIM, 0);

    INIT_DELAYED_WORK(&journal->j_work, flush_async_commits);
    journal->j_work_sb = sb;
    return 0;
      free_and_return:
    free_journal_ram(sb);
    return 1;
}

/*
** test for a polite end of the current transaction.  Used by file_write, and should
** be used by delete to make sure they don't write more than can fit inside a single
** transaction
*/
int journal_transaction_should_end(struct reiserfs_transaction_handle *th,
                   int new_alloc)
{
    struct reiserfs_journal *journal = SB_JOURNAL(th->t_super);
    time_t now = get_seconds();
    /* cannot restart while nested */
    BUG_ON(!th->t_trans_id);
    if (th->t_refcount > 1)
        return 0;
    if (journal->j_must_wait > 0 ||
        (journal->j_len_alloc + new_alloc) >= journal->j_max_batch ||
        atomic_read(&(journal->j_jlock)) ||
        (now - journal->j_trans_start_time) > journal->j_max_trans_age ||
        journal->j_cnode_free < (journal->j_trans_max * 3)) {
        return 1;
    }

    journal->j_len_alloc += new_alloc;
    th->t_blocks_allocated += new_alloc ;
    return 0;
}

/* this must be called inside a transaction
*/
void reiserfs_block_writes(struct reiserfs_transaction_handle *th)
{
    struct reiserfs_journal *journal = SB_JOURNAL(th->t_super);
    BUG_ON(!th->t_trans_id);
    journal->j_must_wait = 1;
    set_bit(J_WRITERS_BLOCKED, &journal->j_state);
    return;
}

/* this must be called without a transaction started
*/
void reiserfs_allow_writes(struct super_block *s)
{
    struct reiserfs_journal *journal = SB_JOURNAL(s);
    clear_bit(J_WRITERS_BLOCKED, &journal->j_state);
    wake_up(&journal->j_join_wait);
}

/* this must be called without a transaction started
*/
void reiserfs_wait_on_write_block(struct super_block *s)
{
    struct reiserfs_journal *journal = SB_JOURNAL(s);
    wait_event(journal->j_join_wait,
           !test_bit(J_WRITERS_BLOCKED, &journal->j_state));
}

static void queue_log_writer(struct super_block *s)
{
    wait_queue_t wait;
    struct reiserfs_journal *journal = SB_JOURNAL(s);
    set_bit(J_WRITERS_QUEUED, &journal->j_state);

    /*
     * we don't want to use wait_event here because
     * we only want to wait once.
     */
    init_waitqueue_entry(&wait, current);
    add_wait_queue(&journal->j_join_wait, &wait);
    set_current_state(TASK_UNINTERRUPTIBLE);
    if (test_bit(J_WRITERS_QUEUED, &journal->j_state)) {
        reiserfs_write_unlock(s);
        schedule();
        reiserfs_write_lock(s);
    }
    __set_current_state(TASK_RUNNING);
    remove_wait_queue(&journal->j_join_wait, &wait);
}

static void wake_queued_writers(struct super_block *s)
{
    struct reiserfs_journal *journal = SB_JOURNAL(s);
    if (test_and_clear_bit(J_WRITERS_QUEUED, &journal->j_state))
        wake_up(&journal->j_join_wait);
}

static void let_transaction_grow(struct super_block *sb, unsigned int trans_id)
{
    struct reiserfs_journal *journal = SB_JOURNAL(sb);
    unsigned long bcount = journal->j_bcount;
    while (1) {
        reiserfs_write_unlock(sb);
        schedule_timeout_uninterruptible(1);
        reiserfs_write_lock(sb);
        journal->j_current_jl->j_state |= LIST_COMMIT_PENDING;
        while ((atomic_read(&journal->j_wcount) > 0 ||
            atomic_read(&journal->j_jlock)) &&
               journal->j_trans_id == trans_id) {
            queue_log_writer(sb);
        }
        if (journal->j_trans_id != trans_id)
            break;
        if (bcount == journal->j_bcount)
            break;
        bcount = journal->j_bcount;
    }
}

/* join == true if you must join an existing transaction.
** join == false if you can deal with waiting for others to finish
**
** this will block until the transaction is joinable.  send the number of blocks you
** expect to use in nblocks.
*/
static int do_journal_begin_r(struct reiserfs_transaction_handle *th,
                  struct super_block *sb, unsigned long nblocks,
                  int join)
{
    time_t now = get_seconds();
    unsigned int old_trans_id;
    struct reiserfs_journal *journal = SB_JOURNAL(sb);
    struct reiserfs_transaction_handle myth;
    int sched_count = 0;
    int retval;

    reiserfs_check_lock_depth(sb, "journal_begin");
    BUG_ON(nblocks > journal->j_trans_max);

    PROC_INFO_INC(sb, journal.journal_being);
    /* set here for journal_join */
    th->t_refcount = 1;
    th->t_super = sb;

      relock:
    lock_journal(sb);
    if (join != JBEGIN_ABORT && reiserfs_is_journal_aborted(journal)) {
        unlock_journal(sb);
        retval = journal->j_errno;
        goto out_fail;
    }
    journal->j_bcount++;

    if (test_bit(J_WRITERS_BLOCKED, &journal->j_state)) {
        unlock_journal(sb);
        reiserfs_write_unlock(sb);
        reiserfs_wait_on_write_block(sb);
        reiserfs_write_lock(sb);
        PROC_INFO_INC(sb, journal.journal_relock_writers);
        goto relock;
    }
    now = get_seconds();

    /* if there is no room in the journal OR
     ** if this transaction is too old, and we weren't called joinable, wait for it to finish before beginning
     ** we don't sleep if there aren't other writers
     */

    if ((!join && journal->j_must_wait > 0) ||
        (!join
         && (journal->j_len_alloc + nblocks + 2) >= journal->j_max_batch)
        || (!join && atomic_read(&journal->j_wcount) > 0
        && journal->j_trans_start_time > 0
        && (now - journal->j_trans_start_time) >
        journal->j_max_trans_age) || (!join
                          && atomic_read(&journal->j_jlock))
        || (!join && journal->j_cnode_free < (journal->j_trans_max * 3))) {

        old_trans_id = journal->j_trans_id;
        unlock_journal(sb); /* allow others to finish this transaction */

        if (!join && (journal->j_len_alloc + nblocks + 2) >=
            journal->j_max_batch &&
            ((journal->j_len + nblocks + 2) * 100) <
            (journal->j_len_alloc * 75)) {
            if (atomic_read(&journal->j_wcount) > 10) {
                sched_count++;
                queue_log_writer(sb);
                goto relock;
            }
        }
        /* don't mess with joining the transaction if all we have to do is
         * wait for someone else to do a commit
         */
        if (atomic_read(&journal->j_jlock)) {
            while (journal->j_trans_id == old_trans_id &&
                   atomic_read(&journal->j_jlock)) {
                queue_log_writer(sb);
            }
            goto relock;
        }
        retval = journal_join(&myth, sb, 1);
        if (retval)
            goto out_fail;

        /* someone might have ended the transaction while we joined */
        if (old_trans_id != journal->j_trans_id) {
            retval = do_journal_end(&myth, sb, 1, 0);
        } else {
            retval = do_journal_end(&myth, sb, 1, COMMIT_NOW);
        }

        if (retval)
            goto out_fail;

        PROC_INFO_INC(sb, journal.journal_relock_wcount);
        goto relock;
    }
    /* we are the first writer, set trans_id */
    if (journal->j_trans_start_time == 0) {
        journal->j_trans_start_time = get_seconds();
    }
    atomic_inc(&(journal->j_wcount));
    journal->j_len_alloc += nblocks;
    th->t_blocks_logged = 0;
    th->t_blocks_allocated = nblocks;
    th->t_trans_id = journal->j_trans_id;
    unlock_journal(sb);
    INIT_LIST_HEAD(&th->t_list);
    return 0;

      out_fail:
    memset(th, 0, sizeof(*th));
    /* Re-set th->t_super, so we can properly keep track of how many
     * persistent transactions there are. We need to do this so if this
     * call is part of a failed restart_transaction, we can free it later */
    th->t_super = sb;
    return retval;
}

struct reiserfs_transaction_handle *reiserfs_persistent_transaction(struct
                                    super_block
                                    *s,
                                    int nblocks)
{
    int ret;
    struct reiserfs_transaction_handle *th;

    /* if we're nesting into an existing transaction.  It will be
     ** persistent on its own
     */
    if (reiserfs_transaction_running(s)) {
        th = current->journal_info;
        th->t_refcount++;
        BUG_ON(th->t_refcount < 2);
        
        return th;
    }
    th = kmalloc(sizeof(struct reiserfs_transaction_handle), GFP_NOFS);
    if (!th)
        return NULL;
    ret = journal_begin(th, s, nblocks);
    if (ret) {
        kfree(th);
        return NULL;
    }

    SB_JOURNAL(s)->j_persistent_trans++;
    return th;
}

int reiserfs_end_persistent_transaction(struct reiserfs_transaction_handle *th)
{
    struct super_block *s = th->t_super;
    int ret = 0;
    if (th->t_trans_id)
        ret = journal_end(th, th->t_super, th->t_blocks_allocated);
    else
        ret = -EIO;
    if (th->t_refcount == 0) {
        SB_JOURNAL(s)->j_persistent_trans--;
        kfree(th);
    }
    return ret;
}

static int journal_join(struct reiserfs_transaction_handle *th,
            struct super_block *sb, unsigned long nblocks)
{
    struct reiserfs_transaction_handle *cur_th = current->journal_info;

    /* this keeps do_journal_end from NULLing out the current->journal_info
     ** pointer
     */
    th->t_handle_save = cur_th;
    BUG_ON(cur_th && cur_th->t_refcount > 1);
    return do_journal_begin_r(th, sb, nblocks, JBEGIN_JOIN);
}

int journal_join_abort(struct reiserfs_transaction_handle *th,
               struct super_block *sb, unsigned long nblocks)
{
    struct reiserfs_transaction_handle *cur_th = current->journal_info;

    /* this keeps do_journal_end from NULLing out the current->journal_info
     ** pointer
     */
    th->t_handle_save = cur_th;
    BUG_ON(cur_th && cur_th->t_refcount > 1);
    return do_journal_begin_r(th, sb, nblocks, JBEGIN_ABORT);
}

int journal_begin(struct reiserfs_transaction_handle *th,
          struct super_block *sb, unsigned long nblocks)
{
    struct reiserfs_transaction_handle *cur_th = current->journal_info;
    int ret;

    th->t_handle_save = NULL;
    if (cur_th) {
        /* we are nesting into the current transaction */
        if (cur_th->t_super == sb) {
            BUG_ON(!cur_th->t_refcount);
            cur_th->t_refcount++;
            memcpy(th, cur_th, sizeof(*th));
            if (th->t_refcount <= 1)
                reiserfs_warning(sb, "reiserfs-2005",
                         "BAD: refcount <= 1, but "
                         "journal_info != 0");
            return 0;
        } else {
            /* we've ended up with a handle from a different filesystem.
             ** save it and restore on journal_end.  This should never
             ** really happen...
             */
            reiserfs_warning(sb, "clm-2100",
                     "nesting info a different FS");
            th->t_handle_save = current->journal_info;
            current->journal_info = th;
        }
    } else {
        current->journal_info = th;
    }
    ret = do_journal_begin_r(th, sb, nblocks, JBEGIN_REG);
    BUG_ON(current->journal_info != th);

    /* I guess this boils down to being the reciprocal of clm-2100 above.
     * If do_journal_begin_r fails, we need to put it back, since journal_end
     * won't be called to do it. */
    if (ret)
        current->journal_info = th->t_handle_save;
    else
        BUG_ON(!th->t_refcount);

    return ret;
}

/*
** puts bh into the current transaction.  If it was already there, reorders removes the
** old pointers from the hash, and puts new ones in (to make sure replay happen in the right order).
**
** if it was dirty, cleans and files onto the clean list.  I can't let it be dirty again until the
** transaction is committed.
**
** if j_len, is bigger than j_len_alloc, it pushes j_len_alloc to 10 + j_len.
*/
int journal_mark_dirty(struct reiserfs_transaction_handle *th,
               struct super_block *sb, struct buffer_head *bh)
{
    struct reiserfs_journal *journal = SB_JOURNAL(sb);
    struct reiserfs_journal_cnode *cn = NULL;
    int count_already_incd = 0;
    int prepared = 0;
    BUG_ON(!th->t_trans_id);

    PROC_INFO_INC(sb, journal.mark_dirty);
    if (th->t_trans_id != journal->j_trans_id) {
        reiserfs_panic(th->t_super, "journal-1577",
                   "handle trans id %ld != current trans id %ld",
                   th->t_trans_id, journal->j_trans_id);
    }

    prepared = test_clear_buffer_journal_prepared(bh);
    clear_buffer_journal_restore_dirty(bh);
    /* already in this transaction, we are done */
    if (buffer_journaled(bh)) {
        PROC_INFO_INC(sb, journal.mark_dirty_already);
        return 0;
    }

    /* this must be turned into a panic instead of a warning.  We can't allow
     ** a dirty or journal_dirty or locked buffer to be logged, as some changes
     ** could get to disk too early.  NOT GOOD.
     */
    if (!prepared || buffer_dirty(bh)) {
        reiserfs_warning(sb, "journal-1777",
                 "buffer %llu bad state "
                 "%cPREPARED %cLOCKED %cDIRTY %cJDIRTY_WAIT",
                 (unsigned long long)bh->b_blocknr,
                 prepared ? ' ' : '!',
                 buffer_locked(bh) ? ' ' : '!',
                 buffer_dirty(bh) ? ' ' : '!',
                 buffer_journal_dirty(bh) ? ' ' : '!');
    }

    if (atomic_read(&(journal->j_wcount)) <= 0) {
        reiserfs_warning(sb, "journal-1409",
                 "returning because j_wcount was %d",
                 atomic_read(&(journal->j_wcount)));
        return 1;
    }
    /* this error means I've screwed up, and we've overflowed the transaction.
     ** Nothing can be done here, except make the FS readonly or panic.
     */
    if (journal->j_len >= journal->j_trans_max) {
        reiserfs_panic(th->t_super, "journal-1413",
                   "j_len (%lu) is too big",
                   journal->j_len);
    }

    if (buffer_journal_dirty(bh)) {
        count_already_incd = 1;
        PROC_INFO_INC(sb, journal.mark_dirty_notjournal);
        clear_buffer_journal_dirty(bh);
    }

    if (journal->j_len > journal->j_len_alloc) {
        journal->j_len_alloc = journal->j_len + JOURNAL_PER_BALANCE_CNT;
    }

    set_buffer_journaled(bh);

    /* now put this guy on the end */
    if (!cn) {
        cn = get_cnode(sb);
        if (!cn) {
            reiserfs_panic(sb, "journal-4", "get_cnode failed!");
        }

        if (th->t_blocks_logged == th->t_blocks_allocated) {
            th->t_blocks_allocated += JOURNAL_PER_BALANCE_CNT;
            journal->j_len_alloc += JOURNAL_PER_BALANCE_CNT;
        }
        th->t_blocks_logged++;
        journal->j_len++;

        cn->bh = bh;
        cn->blocknr = bh->b_blocknr;
        cn->sb = sb;
        cn->jlist = NULL;
        insert_journal_hash(journal->j_hash_table, cn);
        if (!count_already_incd) {
            get_bh(bh);
        }
    }
    cn->next = NULL;
    cn->prev = journal->j_last;
    cn->bh = bh;
    if (journal->j_last) {
        journal->j_last->next = cn;
        journal->j_last = cn;
    } else {
        journal->j_first = cn;
        journal->j_last = cn;
    }
    reiserfs_schedule_old_flush(sb);
    return 0;
}

int journal_end(struct reiserfs_transaction_handle *th,
        struct super_block *sb, unsigned long nblocks)
{
    if (!current->journal_info && th->t_refcount > 1)
        reiserfs_warning(sb, "REISER-NESTING",
                 "th NULL, refcount %d", th->t_refcount);

    if (!th->t_trans_id) {
        WARN_ON(1);
        return -EIO;
    }

    th->t_refcount--;
    if (th->t_refcount > 0) {
        struct reiserfs_transaction_handle *cur_th =
            current->journal_info;

        /* we aren't allowed to close a nested transaction on a different
         ** filesystem from the one in the task struct
         */
        BUG_ON(cur_th->t_super != th->t_super);

        if (th != cur_th) {
            memcpy(current->journal_info, th, sizeof(*th));
            th->t_trans_id = 0;
        }
        return 0;
    } else {
        return do_journal_end(th, sb, nblocks, 0);
    }
}

/* removes from the current transaction, relsing and descrementing any counters.
** also files the removed buffer directly onto the clean list
**
** called by journal_mark_freed when a block has been deleted
**
** returns 1 if it cleaned and relsed the buffer. 0 otherwise
*/
static int remove_from_transaction(struct super_block *sb,
                   b_blocknr_t blocknr, int already_cleaned)
{
    struct buffer_head *bh;
    struct reiserfs_journal_cnode *cn;
    struct reiserfs_journal *journal = SB_JOURNAL(sb);
    int ret = 0;

    cn = get_journal_hash_dev(sb, journal->j_hash_table, blocknr);
    if (!cn || !cn->bh) {
        return ret;
    }
    bh = cn->bh;
    if (cn->prev) {
        cn->prev->next = cn->next;
    }
    if (cn->next) {
        cn->next->prev = cn->prev;
    }
    if (cn == journal->j_first) {
        journal->j_first = cn->next;
    }
    if (cn == journal->j_last) {
        journal->j_last = cn->prev;
    }
    if (bh)
        remove_journal_hash(sb, journal->j_hash_table, NULL,
                    bh->b_blocknr, 0);
    clear_buffer_journaled(bh); /* don't log this one */

    if (!already_cleaned) {
        clear_buffer_journal_dirty(bh);
        clear_buffer_dirty(bh);
        clear_buffer_journal_test(bh);
        put_bh(bh);
        if (atomic_read(&(bh->b_count)) < 0) {
            reiserfs_warning(sb, "journal-1752",
                     "b_count < 0");
        }
        ret = 1;
    }
    journal->j_len--;
    journal->j_len_alloc--;
    free_cnode(sb, cn);
    return ret;
}

/*
** for any cnode in a journal list, it can only be dirtied of all the
** transactions that include it are committed to disk.
** this checks through each transaction, and returns 1 if you are allowed to dirty,
** and 0 if you aren't
**
** it is called by dirty_journal_list, which is called after flush_commit_list has gotten all the log
** blocks for a given transaction on disk
**
*/
static int can_dirty(struct reiserfs_journal_cnode *cn)
{
    struct super_block *sb = cn->sb;
    b_blocknr_t blocknr = cn->blocknr;
    struct reiserfs_journal_cnode *cur = cn->hprev;
    int can_dirty = 1;

    /* first test hprev.  These are all newer than cn, so any node here
     ** with the same block number and dev means this node can't be sent
     ** to disk right now.
     */
    while (cur && can_dirty) {
        if (cur->jlist && cur->bh && cur->blocknr && cur->sb == sb &&
            cur->blocknr == blocknr) {
            can_dirty = 0;
        }
        cur = cur->hprev;
    }
    /* then test hnext.  These are all older than cn.  As long as they
     ** are committed to the log, it is safe to write cn to disk
     */
    cur = cn->hnext;
    while (cur && can_dirty) {
        if (cur->jlist && cur->jlist->j_len > 0 &&
            atomic_read(&(cur->jlist->j_commit_left)) > 0 && cur->bh &&
            cur->blocknr && cur->sb == sb && cur->blocknr == blocknr) {
            can_dirty = 0;
        }
        cur = cur->hnext;
    }
    return can_dirty;
}

/* syncs the commit blocks, but does not force the real buffers to disk
** will wait until the current transaction is done/committed before returning
*/
int journal_end_sync(struct reiserfs_transaction_handle *th,
             struct super_block *sb, unsigned long nblocks)
{
    struct reiserfs_journal *journal = SB_JOURNAL(sb);

    BUG_ON(!th->t_trans_id);
    /* you can sync while nested, very, very bad */
    BUG_ON(th->t_refcount > 1);
    if (journal->j_len == 0) {
        reiserfs_prepare_for_journal(sb, SB_BUFFER_WITH_SB(sb),
                         1);
        journal_mark_dirty(th, sb, SB_BUFFER_WITH_SB(sb));
    }
    return do_journal_end(th, sb, nblocks, COMMIT_NOW | WAIT);
}

/*
** writeback the pending async commits to disk
*/
static void flush_async_commits(struct work_struct *work)
{
    struct reiserfs_journal *journal =
        container_of(work, struct reiserfs_journal, j_work.work);
    struct super_block *sb = journal->j_work_sb;
    struct reiserfs_journal_list *jl;
    struct list_head *entry;

    reiserfs_write_lock(sb);
    if (!list_empty(&journal->j_journal_list)) {
        /* last entry is the youngest, commit it and you get everything */
        entry = journal->j_journal_list.prev;
        jl = JOURNAL_LIST_ENTRY(entry);
        flush_commit_list(sb, jl, 1);
    }
    reiserfs_write_unlock(sb);
}

/*
** flushes any old transactions to disk
** ends the current transaction if it is too old
*/
void reiserfs_flush_old_commits(struct super_block *sb)
{
    time_t now;
    struct reiserfs_transaction_handle th;
    struct reiserfs_journal *journal = SB_JOURNAL(sb);

    now = get_seconds();
    /* safety check so we don't flush while we are replaying the log during
     * mount
     */
    if (list_empty(&journal->j_journal_list))
        return;

    /* check the current transaction.  If there are no writers, and it is
     * too old, finish it, and force the commit blocks to disk
     */
    if (atomic_read(&journal->j_wcount) <= 0 &&
        journal->j_trans_start_time > 0 &&
        journal->j_len > 0 &&
        (now - journal->j_trans_start_time) > journal->j_max_trans_age) {
        if (!journal_join(&th, sb, 1)) {
            reiserfs_prepare_for_journal(sb,
                             SB_BUFFER_WITH_SB(sb),
                             1);
            journal_mark_dirty(&th, sb,
                       SB_BUFFER_WITH_SB(sb));

            /* we're only being called from kreiserfsd, it makes no sense to do
             ** an async commit so that kreiserfsd can do it later
             */
            do_journal_end(&th, sb, 1, COMMIT_NOW | WAIT);
        }
    }
}

/*
** returns 0 if do_journal_end should return right away, returns 1 if do_journal_end should finish the commit
**
** if the current transaction is too old, but still has writers, this will wait on j_join_wait until all
** the writers are done.  By the time it wakes up, the transaction it was called has already ended, so it just
** flushes the commit list and returns 0.
**
** Won't batch when flush or commit_now is set.  Also won't batch when others are waiting on j_join_wait.
**
** Note, we can't allow the journal_end to proceed while there are still writers in the log.
*/
static int check_journal_end(struct reiserfs_transaction_handle *th,
                 struct super_block *sb, unsigned long nblocks,
                 int flags)
{

    time_t now;
    int flush = flags & FLUSH_ALL;
    int commit_now = flags & COMMIT_NOW;
    int wait_on_commit = flags & WAIT;
    struct reiserfs_journal_list *jl;
    struct reiserfs_journal *journal = SB_JOURNAL(sb);

    BUG_ON(!th->t_trans_id);

    if (th->t_trans_id != journal->j_trans_id) {
        reiserfs_panic(th->t_super, "journal-1577",
                   "handle trans id %ld != current trans id %ld",
                   th->t_trans_id, journal->j_trans_id);
    }

    journal->j_len_alloc -= (th->t_blocks_allocated - th->t_blocks_logged);
    if (atomic_read(&(journal->j_wcount)) > 0) {    /* <= 0 is allowed.  unmounting might not call begin */
        atomic_dec(&(journal->j_wcount));
    }

    /* BUG, deal with case where j_len is 0, but people previously freed blocks need to be released
     ** will be dealt with by next transaction that actually writes something, but should be taken
     ** care of in this trans
     */
    BUG_ON(journal->j_len == 0);

    /* if wcount > 0, and we are called to with flush or commit_now,
     ** we wait on j_join_wait.  We will wake up when the last writer has
     ** finished the transaction, and started it on its way to the disk.
     ** Then, we flush the commit or journal list, and just return 0
     ** because the rest of journal end was already done for this transaction.
     */
    if (atomic_read(&(journal->j_wcount)) > 0) {
        if (flush || commit_now) {
            unsigned trans_id;

            jl = journal->j_current_jl;
            trans_id = jl->j_trans_id;
            if (wait_on_commit)
                jl->j_state |= LIST_COMMIT_PENDING;
            atomic_set(&(journal->j_jlock), 1);
            if (flush) {
                journal->j_next_full_flush = 1;
            }
            unlock_journal(sb);

            /* sleep while the current transaction is still j_jlocked */
            while (journal->j_trans_id == trans_id) {
                if (atomic_read(&journal->j_jlock)) {
                    queue_log_writer(sb);
                } else {
                    lock_journal(sb);
                    if (journal->j_trans_id == trans_id) {
                        atomic_set(&(journal->j_jlock),
                               1);
                    }
                    unlock_journal(sb);
                }
            }
            BUG_ON(journal->j_trans_id == trans_id);
            
            if (commit_now
                && journal_list_still_alive(sb, trans_id)
                && wait_on_commit) {
                flush_commit_list(sb, jl, 1);
            }
            return 0;
        }
        unlock_journal(sb);
        return 0;
    }

    /* deal with old transactions where we are the last writers */
    now = get_seconds();
    if ((now - journal->j_trans_start_time) > journal->j_max_trans_age) {
        commit_now = 1;
        journal->j_next_async_flush = 1;
    }
    /* don't batch when someone is waiting on j_join_wait */
    /* don't batch when syncing the commit or flushing the whole trans */
    if (!(journal->j_must_wait > 0) && !(atomic_read(&(journal->j_jlock)))
        && !flush && !commit_now && (journal->j_len < journal->j_max_batch)
        && journal->j_len_alloc < journal->j_max_batch
        && journal->j_cnode_free > (journal->j_trans_max * 3)) {
        journal->j_bcount++;
        unlock_journal(sb);
        return 0;
    }

    if (journal->j_start > SB_ONDISK_JOURNAL_SIZE(sb)) {
        reiserfs_panic(sb, "journal-003",
                   "j_start (%ld) is too high",
                   journal->j_start);
    }
    return 1;
}

/*
** Does all the work that makes deleting blocks safe.
** when deleting a block mark BH_JNew, just remove it from the current transaction, clean it's buffer_head and move on.
**
** otherwise:
** set a bit for the block in the journal bitmap.  That will prevent it from being allocated for unformatted nodes
** before this transaction has finished.
**
** mark any cnodes for this block as BLOCK_FREED, and clear their bh pointers.  That will prevent any old transactions with
** this block from trying to flush to the real location.  Since we aren't removing the cnode from the journal_list_hash,
** the block can't be reallocated yet.
**
** Then remove it from the current transaction, decrementing any counters and filing it on the clean list.
*/
int journal_mark_freed(struct reiserfs_transaction_handle *th,
               struct super_block *sb, b_blocknr_t blocknr)
{
    struct reiserfs_journal *journal = SB_JOURNAL(sb);
    struct reiserfs_journal_cnode *cn = NULL;
    struct buffer_head *bh = NULL;
    struct reiserfs_list_bitmap *jb = NULL;
    int cleaned = 0;
    BUG_ON(!th->t_trans_id);

    cn = get_journal_hash_dev(sb, journal->j_hash_table, blocknr);
    if (cn && cn->bh) {
        bh = cn->bh;
        get_bh(bh);
    }
    /* if it is journal new, we just remove it from this transaction */
    if (bh && buffer_journal_new(bh)) {
        clear_buffer_journal_new(bh);
        clear_prepared_bits(bh);
        reiserfs_clean_and_file_buffer(bh);
        cleaned = remove_from_transaction(sb, blocknr, cleaned);
    } else {
        /* set the bit for this block in the journal bitmap for this transaction */
        jb = journal->j_current_jl->j_list_bitmap;
        if (!jb) {
            reiserfs_panic(sb, "journal-1702",
                       "journal_list_bitmap is NULL");
        }
        set_bit_in_list_bitmap(sb, blocknr, jb);

        /* Note, the entire while loop is not allowed to schedule.  */

        if (bh) {
            clear_prepared_bits(bh);
            reiserfs_clean_and_file_buffer(bh);
        }
        cleaned = remove_from_transaction(sb, blocknr, cleaned);

        /* find all older transactions with this block, make sure they don't try to write it out */
        cn = get_journal_hash_dev(sb, journal->j_list_hash_table,
                      blocknr);
        while (cn) {
            if (sb == cn->sb && blocknr == cn->blocknr) {
                set_bit(BLOCK_FREED, &cn->state);
                if (cn->bh) {
                    if (!cleaned) {
                        /* remove_from_transaction will brelse the buffer if it was 
                         ** in the current trans
                         */
                        clear_buffer_journal_dirty(cn->
                                       bh);
                        clear_buffer_dirty(cn->bh);
                        clear_buffer_journal_test(cn->
                                      bh);
                        cleaned = 1;
                        put_bh(cn->bh);
                        if (atomic_read
                            (&(cn->bh->b_count)) < 0) {
                            reiserfs_warning(sb,
                                 "journal-2138",
                                 "cn->bh->b_count < 0");
                        }
                    }
                    if (cn->jlist) {    /* since we are clearing the bh, we MUST dec nonzerolen */
                        atomic_dec(&
                               (cn->jlist->
                                j_nonzerolen));
                    }
                    cn->bh = NULL;
                }
            }
            cn = cn->hnext;
        }
    }

    if (bh)
        release_buffer_page(bh); /* get_hash grabs the buffer */
    return 0;
}

void reiserfs_update_inode_transaction(struct inode *inode)
{
    struct reiserfs_journal *journal = SB_JOURNAL(inode->i_sb);
    REISERFS_I(inode)->i_jl = journal->j_current_jl;
    REISERFS_I(inode)->i_trans_id = journal->j_trans_id;
}

/*
 * returns -1 on error, 0 if no commits/barriers were done and 1
 * if a transaction was actually committed and the barrier was done
 */
static int __commit_trans_jl(struct inode *inode, unsigned long id,
                 struct reiserfs_journal_list *jl)
{
    struct reiserfs_transaction_handle th;
    struct super_block *sb = inode->i_sb;
    struct reiserfs_journal *journal = SB_JOURNAL(sb);
    int ret = 0;

    /* is it from the current transaction, or from an unknown transaction? */
    if (id == journal->j_trans_id) {
        jl = journal->j_current_jl;
        /* try to let other writers come in and grow this transaction */
        let_transaction_grow(sb, id);
        if (journal->j_trans_id != id) {
            goto flush_commit_only;
        }

        ret = journal_begin(&th, sb, 1);
        if (ret)
            return ret;

        /* someone might have ended this transaction while we joined */
        if (journal->j_trans_id != id) {
            reiserfs_prepare_for_journal(sb, SB_BUFFER_WITH_SB(sb),
                             1);
            journal_mark_dirty(&th, sb, SB_BUFFER_WITH_SB(sb));
            ret = journal_end(&th, sb, 1);
            goto flush_commit_only;
        }

        ret = journal_end_sync(&th, sb, 1);
        if (!ret)
            ret = 1;

    } else {
        /* this gets tricky, we have to make sure the journal list in
         * the inode still exists.  We know the list is still around
         * if we've got a larger transaction id than the oldest list
         */
          flush_commit_only:
        if (journal_list_still_alive(inode->i_sb, id)) {
            /*
             * we only set ret to 1 when we know for sure
             * the barrier hasn't been started yet on the commit
             * block.
             */
            if (atomic_read(&jl->j_commit_left) > 1)
                ret = 1;
            flush_commit_list(sb, jl, 1);
            if (journal->j_errno)
                ret = journal->j_errno;
        }
    }
    /* otherwise the list is gone, and long since committed */
    return ret;
}

int reiserfs_commit_for_inode(struct inode *inode)
{
    unsigned int id = REISERFS_I(inode)->i_trans_id;
    struct reiserfs_journal_list *jl = REISERFS_I(inode)->i_jl;

    /* for the whole inode, assume unset id means it was
     * changed in the current transaction.  More conservative
     */
    if (!id || !jl) {
        reiserfs_update_inode_transaction(inode);
        id = REISERFS_I(inode)->i_trans_id;
        /* jl will be updated in __commit_trans_jl */
    }

    return __commit_trans_jl(inode, id, jl);
}

void reiserfs_restore_prepared_buffer(struct super_block *sb,
                      struct buffer_head *bh)
{
    struct reiserfs_journal *journal = SB_JOURNAL(sb);
    PROC_INFO_INC(sb, journal.restore_prepared);
    if (!bh) {
        return;
    }
    if (test_clear_buffer_journal_restore_dirty(bh) &&
        buffer_journal_dirty(bh)) {
        struct reiserfs_journal_cnode *cn;
        cn = get_journal_hash_dev(sb,
                      journal->j_list_hash_table,
                      bh->b_blocknr);
        if (cn && can_dirty(cn)) {
            set_buffer_journal_test(bh);
            mark_buffer_dirty(bh);
        }
    }
    clear_buffer_journal_prepared(bh);
}

extern struct tree_balance *cur_tb;
/*
** before we can change a metadata block, we have to make sure it won't
** be written to disk while we are altering it.  So, we must:
** clean it
** wait on it.
**
*/
int reiserfs_prepare_for_journal(struct super_block *sb,
                 struct buffer_head *bh, int wait)
{
    PROC_INFO_INC(sb, journal.prepare);

    if (!trylock_buffer(bh)) {
        if (!wait)
            return 0;
        lock_buffer(bh);
    }
    set_buffer_journal_prepared(bh);
    if (test_clear_buffer_dirty(bh) && buffer_journal_dirty(bh)) {
        clear_buffer_journal_test(bh);
        set_buffer_journal_restore_dirty(bh);
    }
    unlock_buffer(bh);
    return 1;
}

static void flush_old_journal_lists(struct super_block *s)
{
    struct reiserfs_journal *journal = SB_JOURNAL(s);
    struct reiserfs_journal_list *jl;
    struct list_head *entry;
    time_t now = get_seconds();

    while (!list_empty(&journal->j_journal_list)) {
        entry = journal->j_journal_list.next;
        jl = JOURNAL_LIST_ENTRY(entry);
        /* this check should always be run, to send old lists to disk */
        if (jl->j_timestamp < (now - (JOURNAL_MAX_TRANS_AGE * 4)) &&
            atomic_read(&jl->j_commit_left) == 0 &&
            test_transaction(s, jl)) {
            flush_used_journal_lists(s, jl);
        } else {
            break;
        }
    }
}

/*
** long and ugly.  If flush, will not return until all commit
** blocks and all real buffers in the trans are on disk.
** If no_async, won't return until all commit blocks are on disk.
**
** keep reading, there are comments as you go along
**
** If the journal is aborted, we just clean up. Things like flushing
** journal lists, etc just won't happen.
*/
static int do_journal_end(struct reiserfs_transaction_handle *th,
              struct super_block *sb, unsigned long nblocks,
              int flags)
{
    struct reiserfs_journal *journal = SB_JOURNAL(sb);
    struct reiserfs_journal_cnode *cn, *next, *jl_cn;
    struct reiserfs_journal_cnode *last_cn = NULL;
    struct reiserfs_journal_desc *desc;
    struct reiserfs_journal_commit *commit;
    struct buffer_head *c_bh;   /* commit bh */
    struct buffer_head *d_bh;   /* desc bh */
    int cur_write_start = 0;    /* start index of current log write */
    int old_start;
    int i;
    int flush;
    int wait_on_commit;
    struct reiserfs_journal_list *jl, *temp_jl;
    struct list_head *entry, *safe;
    unsigned long jindex;
    unsigned int commit_trans_id;
    int trans_half;

    BUG_ON(th->t_refcount > 1);
    BUG_ON(!th->t_trans_id);

    /* protect flush_older_commits from doing mistakes if the
           transaction ID counter gets overflowed.  */
    if (th->t_trans_id == ~0U)
        flags |= FLUSH_ALL | COMMIT_NOW | WAIT;
    flush = flags & FLUSH_ALL;
    wait_on_commit = flags & WAIT;

    current->journal_info = th->t_handle_save;
    reiserfs_check_lock_depth(sb, "journal end");
    if (journal->j_len == 0) {
        reiserfs_prepare_for_journal(sb, SB_BUFFER_WITH_SB(sb),
                         1);
        journal_mark_dirty(th, sb, SB_BUFFER_WITH_SB(sb));
    }

    lock_journal(sb);
    if (journal->j_next_full_flush) {
        flags |= FLUSH_ALL;
        flush = 1;
    }
    if (journal->j_next_async_flush) {
        flags |= COMMIT_NOW | WAIT;
        wait_on_commit = 1;
    }

    /* check_journal_end locks the journal, and unlocks if it does not return 1
     ** it tells us if we should continue with the journal_end, or just return
     */
    if (!check_journal_end(th, sb, nblocks, flags)) {
        reiserfs_schedule_old_flush(sb);
        wake_queued_writers(sb);
        reiserfs_async_progress_wait(sb);
        goto out;
    }

    /* check_journal_end might set these, check again */
    if (journal->j_next_full_flush) {
        flush = 1;
    }

    /*
     ** j must wait means we have to flush the log blocks, and the real blocks for
     ** this transaction
     */
    if (journal->j_must_wait > 0) {
        flush = 1;
    }
#ifdef REISERFS_PREALLOCATE
    /* quota ops might need to nest, setup the journal_info pointer for them
     * and raise the refcount so that it is > 0. */
    current->journal_info = th;
    th->t_refcount++;
    reiserfs_discard_all_prealloc(th);  /* it should not involve new blocks into
                         * the transaction */
    th->t_refcount--;
    current->journal_info = th->t_handle_save;
#endif

    /* setup description block */
    d_bh =
        journal_getblk(sb,
               SB_ONDISK_JOURNAL_1st_BLOCK(sb) +
               journal->j_start);
    set_buffer_uptodate(d_bh);
    desc = (struct reiserfs_journal_desc *)(d_bh)->b_data;
    memset(d_bh->b_data, 0, d_bh->b_size);
    memcpy(get_journal_desc_magic(d_bh), JOURNAL_DESC_MAGIC, 8);
    set_desc_trans_id(desc, journal->j_trans_id);

    /* setup commit block.  Don't write (keep it clean too) this one until after everyone else is written */
    c_bh = journal_getblk(sb, SB_ONDISK_JOURNAL_1st_BLOCK(sb) +
                  ((journal->j_start + journal->j_len +
                1) % SB_ONDISK_JOURNAL_SIZE(sb)));
    commit = (struct reiserfs_journal_commit *)c_bh->b_data;
    memset(c_bh->b_data, 0, c_bh->b_size);
    set_commit_trans_id(commit, journal->j_trans_id);
    set_buffer_uptodate(c_bh);

    /* init this journal list */
    jl = journal->j_current_jl;

    /* we lock the commit before doing anything because
     * we want to make sure nobody tries to run flush_commit_list until
     * the new transaction is fully setup, and we've already flushed the
     * ordered bh list
     */
    reiserfs_mutex_lock_safe(&jl->j_commit_mutex, sb);

    /* save the transaction id in case we need to commit it later */
    commit_trans_id = jl->j_trans_id;

    atomic_set(&jl->j_older_commits_done, 0);
    jl->j_trans_id = journal->j_trans_id;
    jl->j_timestamp = journal->j_trans_start_time;
    jl->j_commit_bh = c_bh;
    jl->j_start = journal->j_start;
    jl->j_len = journal->j_len;
    atomic_set(&jl->j_nonzerolen, journal->j_len);
    atomic_set(&jl->j_commit_left, journal->j_len + 2);
    jl->j_realblock = NULL;

    /* The ENTIRE FOR LOOP MUST not cause schedule to occur.
     **  for each real block, add it to the journal list hash,
     ** copy into real block index array in the commit or desc block
     */
    trans_half = journal_trans_half(sb->s_blocksize);
    for (i = 0, cn = journal->j_first; cn; cn = cn->next, i++) {
        if (buffer_journaled(cn->bh)) {
            jl_cn = get_cnode(sb);
            if (!jl_cn) {
                reiserfs_panic(sb, "journal-1676",
                           "get_cnode returned NULL");
            }
            if (i == 0) {
                jl->j_realblock = jl_cn;
            }
            jl_cn->prev = last_cn;
            jl_cn->next = NULL;
            if (last_cn) {
                last_cn->next = jl_cn;
            }
            last_cn = jl_cn;
            /* make sure the block we are trying to log is not a block
               of journal or reserved area */

            if (is_block_in_log_or_reserved_area
                (sb, cn->bh->b_blocknr)) {
                reiserfs_panic(sb, "journal-2332",
                           "Trying to log block %lu, "
                           "which is a log block",
                           cn->bh->b_blocknr);
            }
            jl_cn->blocknr = cn->bh->b_blocknr;
            jl_cn->state = 0;
            jl_cn->sb = sb;
            jl_cn->bh = cn->bh;
            jl_cn->jlist = jl;
            insert_journal_hash(journal->j_list_hash_table, jl_cn);
            if (i < trans_half) {
                desc->j_realblock[i] =
                    cpu_to_le32(cn->bh->b_blocknr);
            } else {
                commit->j_realblock[i - trans_half] =
                    cpu_to_le32(cn->bh->b_blocknr);
            }
        } else {
            i--;
        }
    }
    set_desc_trans_len(desc, journal->j_len);
    set_desc_mount_id(desc, journal->j_mount_id);
    set_desc_trans_id(desc, journal->j_trans_id);
    set_commit_trans_len(commit, journal->j_len);

    /* special check in case all buffers in the journal were marked for not logging */
    BUG_ON(journal->j_len == 0);

    /* we're about to dirty all the log blocks, mark the description block
     * dirty now too.  Don't mark the commit block dirty until all the
     * others are on disk
     */
    mark_buffer_dirty(d_bh);

    /* first data block is j_start + 1, so add one to cur_write_start wherever you use it */
    cur_write_start = journal->j_start;
    cn = journal->j_first;
    jindex = 1;     /* start at one so we don't get the desc again */
    while (cn) {
        clear_buffer_journal_new(cn->bh);
        /* copy all the real blocks into log area.  dirty log blocks */
        if (buffer_journaled(cn->bh)) {
            struct buffer_head *tmp_bh;
            char *addr;
            struct page *page;
            tmp_bh =
                journal_getblk(sb,
                       SB_ONDISK_JOURNAL_1st_BLOCK(sb) +
                       ((cur_write_start +
                         jindex) %
                        SB_ONDISK_JOURNAL_SIZE(sb)));
            set_buffer_uptodate(tmp_bh);
            page = cn->bh->b_page;
            addr = kmap(page);
            memcpy(tmp_bh->b_data,
                   addr + offset_in_page(cn->bh->b_data),
                   cn->bh->b_size);
            kunmap(page);
            mark_buffer_dirty(tmp_bh);
            jindex++;
            set_buffer_journal_dirty(cn->bh);
            clear_buffer_journaled(cn->bh);
        } else {
            /* JDirty cleared sometime during transaction.  don't log this one */
            reiserfs_warning(sb, "journal-2048",
                     "BAD, buffer in journal hash, "
                     "but not JDirty!");
            brelse(cn->bh);
        }
        next = cn->next;
        free_cnode(sb, cn);
        cn = next;
        reiserfs_write_unlock(sb);
        cond_resched();
        reiserfs_write_lock(sb);
    }

    /* we are done  with both the c_bh and d_bh, but
     ** c_bh must be written after all other commit blocks,
     ** so we dirty/relse c_bh in flush_commit_list, with commit_left <= 1.
     */

    journal->j_current_jl = alloc_journal_list(sb);

    /* now it is safe to insert this transaction on the main list */
    list_add_tail(&jl->j_list, &journal->j_journal_list);
    list_add_tail(&jl->j_working_list, &journal->j_working_list);
    journal->j_num_work_lists++;

    /* reset journal values for the next transaction */
    old_start = journal->j_start;
    journal->j_start =
        (journal->j_start + journal->j_len +
         2) % SB_ONDISK_JOURNAL_SIZE(sb);
    atomic_set(&(journal->j_wcount), 0);
    journal->j_bcount = 0;
    journal->j_last = NULL;
    journal->j_first = NULL;
    journal->j_len = 0;
    journal->j_trans_start_time = 0;
    /* check for trans_id overflow */
    if (++journal->j_trans_id == 0)
        journal->j_trans_id = 10;
    journal->j_current_jl->j_trans_id = journal->j_trans_id;
    journal->j_must_wait = 0;
    journal->j_len_alloc = 0;
    journal->j_next_full_flush = 0;
    journal->j_next_async_flush = 0;
    init_journal_hash(sb);

    // make sure reiserfs_add_jh sees the new current_jl before we
    // write out the tails
    smp_mb();

    /* tail conversion targets have to hit the disk before we end the
     * transaction.  Otherwise a later transaction might repack the tail
     * before this transaction commits, leaving the data block unflushed and
     * clean, if we crash before the later transaction commits, the data block
     * is lost.
     */
    if (!list_empty(&jl->j_tail_bh_list)) {
        reiserfs_write_unlock(sb);
        write_ordered_buffers(&journal->j_dirty_buffers_lock,
                      journal, jl, &jl->j_tail_bh_list);
        reiserfs_write_lock(sb);
    }
    BUG_ON(!list_empty(&jl->j_tail_bh_list));
    mutex_unlock(&jl->j_commit_mutex);

    /* honor the flush wishes from the caller, simple commits can
     ** be done outside the journal lock, they are done below
     **
     ** if we don't flush the commit list right now, we put it into
     ** the work queue so the people waiting on the async progress work
     ** queue don't wait for this proc to flush journal lists and such.
     */
    if (flush) {
        flush_commit_list(sb, jl, 1);
        flush_journal_list(sb, jl, 1);
    } else if (!(jl->j_state & LIST_COMMIT_PENDING))
        queue_delayed_work(commit_wq, &journal->j_work, HZ / 10);

    /* if the next transaction has any chance of wrapping, flush
     ** transactions that might get overwritten.  If any journal lists are very
     ** old flush them as well.
     */
      first_jl:
    list_for_each_safe(entry, safe, &journal->j_journal_list) {
        temp_jl = JOURNAL_LIST_ENTRY(entry);
        if (journal->j_start <= temp_jl->j_start) {
            if ((journal->j_start + journal->j_trans_max + 1) >=
                temp_jl->j_start) {
                flush_used_journal_lists(sb, temp_jl);
                goto first_jl;
            } else if ((journal->j_start +
                    journal->j_trans_max + 1) <
                   SB_ONDISK_JOURNAL_SIZE(sb)) {
                /* if we don't cross into the next transaction and we don't
                 * wrap, there is no way we can overlap any later transactions
                 * break now
                 */
                break;
            }
        } else if ((journal->j_start +
                journal->j_trans_max + 1) >
               SB_ONDISK_JOURNAL_SIZE(sb)) {
            if (((journal->j_start + journal->j_trans_max + 1) %
                 SB_ONDISK_JOURNAL_SIZE(sb)) >=
                temp_jl->j_start) {
                flush_used_journal_lists(sb, temp_jl);
                goto first_jl;
            } else {
                /* we don't overlap anything from out start to the end of the
                 * log, and our wrapped portion doesn't overlap anything at
                 * the start of the log.  We can break
                 */
                break;
            }
        }
    }
    flush_old_journal_lists(sb);

    journal->j_current_jl->j_list_bitmap =
        get_list_bitmap(sb, journal->j_current_jl);

    if (!(journal->j_current_jl->j_list_bitmap)) {
        reiserfs_panic(sb, "journal-1996",
                   "could not get a list bitmap");
    }

    atomic_set(&(journal->j_jlock), 0);
    unlock_journal(sb);
    /* wake up any body waiting to join. */
    clear_bit(J_WRITERS_QUEUED, &journal->j_state);
    wake_up(&(journal->j_join_wait));

    if (!flush && wait_on_commit &&
        journal_list_still_alive(sb, commit_trans_id)) {
        flush_commit_list(sb, jl, 1);
    }
      out:
    reiserfs_check_lock_depth(sb, "journal end2");

    memset(th, 0, sizeof(*th));
    /* Re-set th->t_super, so we can properly keep track of how many
     * persistent transactions there are. We need to do this so if this
     * call is part of a failed restart_transaction, we can free it later */
    th->t_super = sb;

    return journal->j_errno;
}

/* Send the file system read only and refuse new transactions */
void reiserfs_abort_journal(struct super_block *sb, int errno)
{
    struct reiserfs_journal *journal = SB_JOURNAL(sb);
    if (test_bit(J_ABORTED, &journal->j_state))
        return;

    if (!journal->j_errno)
        journal->j_errno = errno;

    sb->s_flags |= MS_RDONLY;
    set_bit(J_ABORTED, &journal->j_state);

#ifdef CONFIG_REISERFS_CHECK
    dump_stack();
#endif
}