/*
** Write ahead logging implementation copyright Chris Mason 2000
**
** The background commits make this code very interelated, 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 <linux/reiserfs_fs.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/fcntl.h>
#include <linux/stat.h>
#include <linux/string.h>
#include <linux/smp_lock.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 <asm/system.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 void disable_barrier(struct super_block *s)
{
        REISERFS_SB(s)->s_mount_opt &= ~(1 << REISERFS_BARRIER_FLUSH);
        printk("reiserfs: disabling flush barriers on %s\n",
               reiserfs_bdevname(s));
}

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 = vmalloc(mem);
                if (!jb->bitmaps) {
                        reiserfs_warning(sb, "clm-2000", "unable to "
                                         "allocate bitmaps for journal lists");
                        failed = 1;
                        break;
                }
                memset(jb->bitmaps, 0, mem);
        }
        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 = vmalloc(num_cnodes * sizeof(struct reiserfs_journal_cnode));
        if (!head) {
                return NULL;
        }
        memset(head, 0, num_cnodes * sizeof(struct reiserfs_journal_cnode));
        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);
}

/* utility function to force a BUG if it is called without the big
** kernel lock held.  caller is the string printed just before calling BUG()
*/
void reiserfs_check_lock_depth(struct super_block *sb, char *caller)
{
#ifdef CONFIG_SMP
        if (current->lock_depth < 0) {
                reiserfs_panic(sb, "journal-1", "%s called without kernel "
                               "lock held", caller);
        }
#else
        ;
#endif
}

/* 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);
        mutex_lock(&SB_JOURNAL(sb)->j_mutex);
}

/* 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);
}

static int submit_barrier_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();
        return submit_bh(WRITE_BARRIER, bh);
}

static void check_barrier_completion(struct super_block *s,
                                     struct buffer_head *bh)
{
        if (buffer_eopnotsupp(bh)) {
                clear_buffer_eopnotsupp(bh);
                disable_barrier(s);
                set_buffer_uptodate(bh);
                set_buffer_dirty(bh);
                sync_dirty_buffer(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;
        get_fs_excl();
        for (i = 0; i < chunk->nr; i++) {
                submit_logged_buffer(chunk->bh[i]);
        }
        chunk->nr = 0;
        put_fs_excl();
}

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

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)
{
        DEFINE_WAIT(wait);
        struct reiserfs_journal *j = SB_JOURNAL(s);
        if (atomic_read(&j->j_async_throttle))
                congestion_wait(BLK_RW_ASYNC, HZ / 10);

        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 barrier = 0;
        int retval = 0;
        int write_len;

        reiserfs_check_lock_depth(s, "flush_commit_list");

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

        get_fs_excl();

        /* 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 */
        mutex_lock(&jl->j_commit_mutex);
        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;
                unlock_kernel();
                ret = write_ordered_buffers(&journal->j_dirty_buffers_lock,
                                            journal, jl, &jl->j_bh_list);
                if (ret < 0 && retval == 0)
                        retval = ret;
                lock_kernel();
        }
        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))
                            ll_rw_block(WRITE, 1, &tbh) ;
                        put_bh(tbh) ;
                }
        }
        atomic_dec(&journal->j_async_throttle);

        /* We're skipping the commit if there's an error */
        if (retval || reiserfs_is_journal_aborted(journal))
                barrier = 0;

        /* wait on everything written so far before writing the commit
         * if we are in barrier mode, send the commit down now
         */
        barrier = reiserfs_barrier_flush(s);
        if (barrier) {
                int ret;
                lock_buffer(jl->j_commit_bh);
                ret = submit_barrier_buffer(jl->j_commit_bh);
                if (ret == -EOPNOTSUPP) {
                        set_buffer_uptodate(jl->j_commit_bh);
                        disable_barrier(s);
                        barrier = 0;
                }
        }
        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);
                wait_on_buffer(tbh);
                // since we're using ll_rw_blk above, it might have skipped over
                // a locked buffer.  Double check here
                //
                if (buffer_dirty(tbh))  /* redundant, sync_dirty_buffer() checks */
                        sync_dirty_buffer(tbh);
                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 (!barrier) {
                /* 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) ;
                        sync_dirty_buffer(jl->j_commit_bh) ;
                }
        } else
                wait_on_buffer(jl->j_commit_bh);

        check_barrier_completion(s, jl->j_commit_bh);

        /* 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__);
        put_fs_excl();
        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))) {
                        wait_on_buffer((journal->j_header_bh));
                        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);

                if (reiserfs_barrier_flush(sb)) {
                        int ret;
                        lock_buffer(journal->j_header_bh);
                        ret = submit_barrier_buffer(journal->j_header_bh);
                        if (ret == -EOPNOTSUPP) {
                                set_buffer_uptodate(journal->j_header_bh);
                                disable_barrier(sb);
                                goto sync;
                        }
                        wait_on_buffer(journal->j_header_bh);
                        check_barrier_completion(sb, journal->j_header_bh);
                } else {
                      sync:
                        set_buffer_dirty(journal->j_header_bh);
                        sync_dirty_buffer(journal->j_header_bh);
                }
                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) {
                mutex_lock(&journal->j_flush_mutex);
        } 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;
        }

        get_fs_excl();

        /* 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");
                                }
                                wait_on_buffer(cn->bh);
                                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);
        put_fs_excl();
        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;

        mutex_lock(&journal->j_flush_mutex);
        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);
        flush_workqueue(commit_wq);
        if (!reiserfs_mounted_fs_count) {
                destroy_workqueue(commit_wq);
                commit_wq = NULL;
        }

        free_journal_ram(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;
        }
        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++) {
                wait_on_buffer(log_blocks[i]);
                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]);
                ll_rw_block(SWRITE, 1, real_blocks + i);
        }
        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;
        }

        if (continue_replay && bdev_read_only(sb->s_bdev)) {
                reiserfs_warning(sb, "clm-2076",
                                 "device is readonly, unable to replay log");
                return -1;
        }

        /* 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) {
                if (journal->j_dev_bd->bd_dev != super->s_dev)
                        bd_release(journal->j_dev_bd);
                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;
        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])) {
                journal->j_dev_bd = open_by_devnum(jdev, blkdev_mode);
                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) {
                        result = bd_claim(journal->j_dev_bd, journal);
                        if (result) {
                                blkdev_put(journal->j_dev_bd, blkdev_mode);
                                return result;
                        }

                        set_blocksize(journal->j_dev_bd, super->s_blocksize);
                }

                return 0;
        }

        journal->j_dev_mode = blkdev_mode;
        journal->j_dev_bd = open_bdev_exclusive(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;
}

/**
 * When creating/tuning a file system user can assign some
 * journal params within boundaries which depend on the ratio
 * blocksize/standard_blocksize.
 *
 * For blocks >= standard_blocksize transaction size should
 * be not less then JOURNAL_TRANS_MIN_DEFAULT, and not more
 * then JOURNAL_TRANS_MAX_DEFAULT.
 *
 * For blocks < standard_blocksize these boundaries should be
 * decreased proportionally.
 */
#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];

        journal = SB_JOURNAL(sb) = vmalloc(sizeof(struct reiserfs_journal));
        if (!journal) {
                reiserfs_warning(sb, "journal-1256",
                                 "unable to get memory for journal structure");
                return 1;
        }
        memset(journal, 0, sizeof(struct reiserfs_journal));
        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 withing 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;
        jl->j_list_bitmap = get_list_bitmap(sb, jl);
        if (!jl->j_list_bitmap) {
                reiserfs_warning(sb, "journal-2005",
                                 "get_list_bitmap failed for journal list 0");
                goto free_and_return;
        }
        if (journal_read(sb) < 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 = create_workqueue("reiserfs");

        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;
        }
        /* protected by the BKL here */
        journal->j_len_alloc += new_alloc;
        th->t_blocks_allocated += new_alloc ;
        return 0;
}

/* this must be called inside a transaction, and requires the
** kernel_lock to be held
*/
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, and does not
** require BKL
*/
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, and does not
** require BKL
*/
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))
                schedule();
        __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) {
                schedule_timeout_uninterruptible(1);
                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.