fedora core 6 1.2949 + vserver 2.2.0
[linux-2.6.git] / fs / jbd / journal.c
index 3c95df4..10fff94 100644 (file)
@@ -1,5 +1,5 @@
 /*
- * linux/fs/journal.c
+ * linux/fs/jbd/journal.c
  *
  * Written by Stephen C. Tweedie <sct@redhat.com>, 1998
  *
 #include <linux/smp_lock.h>
 #include <linux/init.h>
 #include <linux/mm.h>
-#include <linux/suspend.h>
+#include <linux/freezer.h>
 #include <linux/pagemap.h>
-#include <asm/uaccess.h>
+#include <linux/kthread.h>
+#include <linux/poison.h>
 #include <linux/proc_fs.h>
 
+#include <asm/uaccess.h>
+#include <asm/page.h>
+
 EXPORT_SYMBOL(journal_start);
 EXPORT_SYMBOL(journal_restart);
 EXPORT_SYMBOL(journal_extend);
@@ -54,7 +58,6 @@ EXPORT_SYMBOL(journal_sync_buffer);
 #endif
 EXPORT_SYMBOL(journal_flush);
 EXPORT_SYMBOL(journal_revoke);
-EXPORT_SYMBOL(journal_callback_set);
 
 EXPORT_SYMBOL(journal_init_dev);
 EXPORT_SYMBOL(journal_init_inode);
@@ -65,7 +68,6 @@ EXPORT_SYMBOL(journal_set_features);
 EXPORT_SYMBOL(journal_create);
 EXPORT_SYMBOL(journal_load);
 EXPORT_SYMBOL(journal_destroy);
-EXPORT_SYMBOL(journal_recover);
 EXPORT_SYMBOL(journal_update_superblock);
 EXPORT_SYMBOL(journal_abort);
 EXPORT_SYMBOL(journal_errno);
@@ -73,14 +75,16 @@ EXPORT_SYMBOL(journal_ack_err);
 EXPORT_SYMBOL(journal_clear_err);
 EXPORT_SYMBOL(log_wait_commit);
 EXPORT_SYMBOL(journal_start_commit);
+EXPORT_SYMBOL(journal_force_commit_nested);
 EXPORT_SYMBOL(journal_wipe);
 EXPORT_SYMBOL(journal_blocks_per_page);
 EXPORT_SYMBOL(journal_invalidatepage);
 EXPORT_SYMBOL(journal_try_to_free_buffers);
-EXPORT_SYMBOL(journal_bmap);
 EXPORT_SYMBOL(journal_force_commit);
 
 static int journal_convert_superblock_v1(journal_t *, journal_superblock_t *);
+static void __journal_abort_soft (journal_t *journal, int errno);
+static int journal_create_jbd_slab(size_t slab_size);
 
 /*
  * Helper function used to manage commit timeouts
@@ -93,16 +97,6 @@ static void commit_timeout(unsigned long __data)
        wake_up_process(p);
 }
 
-/* Static check for data structure consistency.  There's no code
- * invoked --- we'll just get a linker failure if things aren't right.
- */
-void __journal_internal_check(void)
-{
-       extern void journal_bad_superblock_size(void);
-       if (sizeof(struct journal_superblock_s) != 1024)
-               journal_bad_superblock_size();
-}
-
 /*
  * kjournald: The main thread function used to manage a logging device
  * journal.
@@ -119,24 +113,17 @@ void __journal_internal_check(void)
  *    known as checkpointing, and this thread is responsible for that job.
  */
 
-journal_t *current_journal;            // AKPM: debug
-
-int kjournald(void *arg)
+static int kjournald(void *arg)
 {
-       journal_t *journal = (journal_t *) arg;
+       journal_t *journal = arg;
        transaction_t *transaction;
-       struct timer_list timer;
 
-       current_journal = journal;
-
-       daemonize("kjournald");
-
-       /* Set up an interval timer which can be used to trigger a
-           commit wakeup after the commit interval expires */
-       init_timer(&timer);
-       timer.data = (unsigned long) current;
-       timer.function = commit_timeout;
-       journal->j_commit_timer = &timer;
+       /*
+        * Set up an interval timer which can be used to trigger a commit wakeup
+        * after the commit interval expires
+        */
+       setup_timer(&journal->j_commit_timer, commit_timeout,
+                       (unsigned long)current);
 
        /* Record that the journal thread is running */
        journal->j_task = current;
@@ -151,20 +138,23 @@ int kjournald(void *arg)
        spin_lock(&journal->j_state_lock);
 
 loop:
+       if (journal->j_flags & JFS_UNMOUNT)
+               goto end_loop;
+
        jbd_debug(1, "commit_sequence=%d, commit_request=%d\n",
                journal->j_commit_sequence, journal->j_commit_request);
 
        if (journal->j_commit_sequence != journal->j_commit_request) {
                jbd_debug(1, "OK, requests differ\n");
                spin_unlock(&journal->j_state_lock);
-               del_timer_sync(journal->j_commit_timer);
+               del_timer_sync(&journal->j_commit_timer);
                journal_commit_transaction(journal);
                spin_lock(&journal->j_state_lock);
-               goto end_loop;
+               goto loop;
        }
 
        wake_up(&journal->j_wait_done_commit);
-       if (current->flags & PF_FREEZE) {
+       if (freezing(current)) {
                /*
                 * The simpler the better. Flushing journal isn't a
                 * good idea, because that depends on threads that may
@@ -172,7 +162,7 @@ loop:
                 */
                jbd_debug(1, "Now suspending kjournald\n");
                spin_unlock(&journal->j_state_lock);
-               refrigerator(PF_FREEZE);
+               refrigerator();
                spin_lock(&journal->j_state_lock);
        } else {
                /*
@@ -190,6 +180,8 @@ loop:
                if (transaction && time_after_eq(jiffies,
                                                transaction->t_expires))
                        should_sleep = 0;
+               if (journal->j_flags & JFS_UNMOUNT)
+                       should_sleep = 0;
                if (should_sleep) {
                        spin_unlock(&journal->j_state_lock);
                        schedule();
@@ -208,12 +200,11 @@ loop:
                journal->j_commit_request = transaction->t_tid;
                jbd_debug(1, "woke because of timeout\n");
        }
-end_loop:
-       if (!(journal->j_flags & JFS_UNMOUNT))
-               goto loop;
+       goto loop;
 
+end_loop:
        spin_unlock(&journal->j_state_lock);
-       del_timer_sync(journal->j_commit_timer);
+       del_timer_sync(&journal->j_commit_timer);
        journal->j_task = NULL;
        wake_up(&journal->j_wait_done_commit);
        jbd_debug(1, "Journal thread exiting.\n");
@@ -222,7 +213,7 @@ end_loop:
 
 static void journal_start_thread(journal_t *journal)
 {
-       kernel_thread(kjournald, journal, CLONE_VM|CLONE_FS|CLONE_FILES);
+       kthread_run(kjournald, journal, "kjournald");
        wait_event(journal->j_wait_done_commit, journal->j_task != 0);
 }
 
@@ -280,7 +271,7 @@ static void journal_kill_thread(journal_t *journal)
 int journal_write_metadata_buffer(transaction_t *transaction,
                                  struct journal_head  *jh_in,
                                  struct journal_head **jh_out,
-                                 int blocknr)
+                                 unsigned long blocknr)
 {
        int need_copy_out = 0;
        int done_copy_out = 0;
@@ -324,8 +315,8 @@ repeat:
        /*
         * Check for escaping
         */
-       if (*((unsigned int *)(mapped_data + new_offset)) ==
-                               htonl(JFS_MAGIC_NUMBER)) {
+       if (*((__be32 *)(mapped_data + new_offset)) ==
+                               cpu_to_be32(JFS_MAGIC_NUMBER)) {
                need_copy_out = 1;
                do_escape = 1;
        }
@@ -338,10 +329,10 @@ repeat:
                char *tmp;
 
                jbd_unlock_bh_state(bh_in);
-               tmp = jbd_rep_kmalloc(bh_in->b_size, GFP_NOFS);
+               tmp = jbd_slab_alloc(bh_in->b_size, GFP_NOFS);
                jbd_lock_bh_state(bh_in);
                if (jh_in->b_frozen_data) {
-                       kfree(tmp);
+                       jbd_slab_free(tmp, bh_in->b_size);
                        goto repeat;
                }
 
@@ -464,6 +455,39 @@ int log_start_commit(journal_t *journal, tid_t tid)
        return ret;
 }
 
+/*
+ * Force and wait upon a commit if the calling process is not within
+ * transaction.  This is used for forcing out undo-protected data which contains
+ * bitmaps, when the fs is running out of space.
+ *
+ * We can only force the running transaction if we don't have an active handle;
+ * otherwise, we will deadlock.
+ *
+ * Returns true if a transaction was started.
+ */
+int journal_force_commit_nested(journal_t *journal)
+{
+       transaction_t *transaction = NULL;
+       tid_t tid;
+
+       spin_lock(&journal->j_state_lock);
+       if (journal->j_running_transaction && !current->journal_info) {
+               transaction = journal->j_running_transaction;
+               __log_start_commit(journal, transaction->t_tid);
+       } else if (journal->j_committing_transaction)
+               transaction = journal->j_committing_transaction;
+
+       if (!transaction) {
+               spin_unlock(&journal->j_state_lock);
+               return 0;       /* Nothing to retry */
+       }
+
+       tid = transaction->t_tid;
+       spin_unlock(&journal->j_state_lock);
+       log_wait_commit(journal, tid);
+       return 1;
+}
+
 /*
  * Start a commit of the current running transaction (if any).  Returns true
  * if a transaction was started, and fills its tid in at *ptid
@@ -554,7 +578,7 @@ int journal_next_log_block(journal_t *journal, unsigned long *retp)
  * this is a no-op.  If needed, we can use j_blk_offset - everything is
  * ready.
  */
-int journal_bmap(journal_t *journal, unsigned long blocknr, 
+int journal_bmap(journal_t *journal, unsigned long blocknr,
                 unsigned long *retp)
 {
        int err = 0;
@@ -585,9 +609,13 @@ int journal_bmap(journal_t *journal, unsigned long blocknr,
  * We play buffer_head aliasing tricks to write data/metadata blocks to
  * the journal without copying their contents, but for journal
  * descriptor blocks we do need to generate bona fide buffers.
+ *
+ * After the caller of journal_get_descriptor_buffer() has finished modifying
+ * the buffer's contents they really should run flush_dcache_page(bh->b_page).
+ * But we don't bother doing that, so there will be coherency problems with
+ * mmaps of blockdevs which hold live JBD-controlled filesystems.
  */
-
-struct journal_head * journal_get_descriptor_buffer(journal_t *journal)
+struct journal_head *journal_get_descriptor_buffer(journal_t *journal)
 {
        struct buffer_head *bh;
        unsigned long blocknr;
@@ -599,8 +627,10 @@ struct journal_head * journal_get_descriptor_buffer(journal_t *journal)
                return NULL;
 
        bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize);
+       lock_buffer(bh);
        memset(bh->b_data, 0, journal->j_blocksize);
-       bh->b_state |= (1 << BH_Dirty);
+       set_buffer_uptodate(bh);
+       unlock_buffer(bh);
        BUFFER_TRACE(bh, "return this buffer");
        return journal_add_journal_head(bh);
 }
@@ -630,8 +660,8 @@ static journal_t * journal_init_common (void)
        init_waitqueue_head(&journal->j_wait_checkpoint);
        init_waitqueue_head(&journal->j_wait_commit);
        init_waitqueue_head(&journal->j_wait_updates);
-       init_MUTEX(&journal->j_barrier);
-       init_MUTEX(&journal->j_checkpoint_sem);
+       mutex_init(&journal->j_barrier);
+       mutex_init(&journal->j_checkpoint_mutex);
        spin_lock_init(&journal->j_revoke_lock);
        spin_lock_init(&journal->j_list_lock);
        spin_lock_init(&journal->j_state_lock);
@@ -666,13 +696,13 @@ fail:
  *  @bdev: Block device on which to create the journal
  *  @fs_dev: Device which hold journalled filesystem for this journal.
  *  @start: Block nr Start of journal.
- *  @len:  Lenght of the journal in blocks.
+ *  @len:  Length of the journal in blocks.
  *  @blocksize: blocksize of journalling device
  *  @returns: a newly created journal_t *
- *  
+ *
  *  journal_init_dev creates a journal which maps a fixed contiguous
  *  range of blocks on an arbitrary block device.
- * 
+ *
  */
 journal_t * journal_init_dev(struct block_device *bdev,
                        struct block_device *fs_dev,
@@ -680,28 +710,40 @@ journal_t * journal_init_dev(struct block_device *bdev,
 {
        journal_t *journal = journal_init_common();
        struct buffer_head *bh;
+       int n;
 
        if (!journal)
                return NULL;
 
+       /* journal descriptor can store up to n blocks -bzzz */
+       journal->j_blocksize = blocksize;
+       n = journal->j_blocksize / sizeof(journal_block_tag_t);
+       journal->j_wbufsize = n;
+       journal->j_wbuf = kmalloc(n * sizeof(struct buffer_head*), GFP_KERNEL);
+       if (!journal->j_wbuf) {
+               printk(KERN_ERR "%s: Cant allocate bhs for commit thread\n",
+                       __FUNCTION__);
+               kfree(journal);
+               journal = NULL;
+               goto out;
+       }
        journal->j_dev = bdev;
        journal->j_fs_dev = fs_dev;
        journal->j_blk_offset = start;
        journal->j_maxlen = len;
-       journal->j_blocksize = blocksize;
 
        bh = __getblk(journal->j_dev, start, journal->j_blocksize);
        J_ASSERT(bh != NULL);
        journal->j_sb_buffer = bh;
        journal->j_superblock = (journal_superblock_t *)bh->b_data;
-
+out:
        return journal;
 }
-/** 
+
+/**
  *  journal_t * journal_init_inode () - creates a journal which maps to a inode.
  *  @inode: An inode to create the journal in
- *  
+ *
  * journal_init_inode creates a journal which maps an on-disk inode as
  * the journal.  The inode must exist already, must support bmap() and
  * must have all data blocks preallocated.
@@ -711,6 +753,7 @@ journal_t * journal_init_inode (struct inode *inode)
        struct buffer_head *bh;
        journal_t *journal = journal_init_common();
        int err;
+       int n;
        unsigned long blocknr;
 
        if (!journal)
@@ -720,13 +763,24 @@ journal_t * journal_init_inode (struct inode *inode)
        journal->j_inode = inode;
        jbd_debug(1,
                  "journal %p: inode %s/%ld, size %Ld, bits %d, blksize %ld\n",
-                 journal, inode->i_sb->s_id, inode->i_ino, 
+                 journal, inode->i_sb->s_id, inode->i_ino,
                  (long long) inode->i_size,
                  inode->i_sb->s_blocksize_bits, inode->i_sb->s_blocksize);
 
        journal->j_maxlen = inode->i_size >> inode->i_sb->s_blocksize_bits;
        journal->j_blocksize = inode->i_sb->s_blocksize;
 
+       /* journal descriptor can store up to n blocks -bzzz */
+       n = journal->j_blocksize / sizeof(journal_block_tag_t);
+       journal->j_wbufsize = n;
+       journal->j_wbuf = kmalloc(n * sizeof(struct buffer_head*), GFP_KERNEL);
+       if (!journal->j_wbuf) {
+               printk(KERN_ERR "%s: Cant allocate bhs for commit thread\n",
+                       __FUNCTION__);
+               kfree(journal);
+               return NULL;
+       }
+
        err = journal_bmap(journal, 0, &blocknr);
        /* If that failed, give up */
        if (err) {
@@ -744,10 +798,10 @@ journal_t * journal_init_inode (struct inode *inode)
        return journal;
 }
 
-/* 
+/*
  * If the journal init or create aborts, we need to mark the journal
  * superblock as being NULL to prevent the journal destroy from writing
- * back a bogus superblock. 
+ * back a bogus superblock.
  */
 static void journal_fail_superblock (journal_t *journal)
 {
@@ -766,10 +820,10 @@ static void journal_fail_superblock (journal_t *journal)
 static int journal_reset(journal_t *journal)
 {
        journal_superblock_t *sb = journal->j_superblock;
-       unsigned int first, last;
+       unsigned long first, last;
 
-       first = ntohl(sb->s_first);
-       last = ntohl(sb->s_maxlen);
+       first = be32_to_cpu(sb->s_first);
+       last = be32_to_cpu(sb->s_maxlen);
 
        journal->j_first = first;
        journal->j_last = last;
@@ -790,13 +844,13 @@ static int journal_reset(journal_t *journal)
        return 0;
 }
 
-/** 
+/**
  * int journal_create() - Initialise the new journal file
  * @journal: Journal to create. This structure must have been initialised
- * 
+ *
  * Given a journal_t structure which tells us which disk blocks we can
  * use, create a new journal superblock and initialise all of the
- * journal fields from scratch.  
+ * journal fields from scratch.
  **/
 int journal_create(journal_t *journal)
 {
@@ -846,12 +900,12 @@ int journal_create(journal_t *journal)
        /* OK, fill in the initial static fields in the new superblock */
        sb = journal->j_superblock;
 
-       sb->s_header.h_magic     = htonl(JFS_MAGIC_NUMBER);
-       sb->s_header.h_blocktype = htonl(JFS_SUPERBLOCK_V2);
+       sb->s_header.h_magic     = cpu_to_be32(JFS_MAGIC_NUMBER);
+       sb->s_header.h_blocktype = cpu_to_be32(JFS_SUPERBLOCK_V2);
 
-       sb->s_blocksize = htonl(journal->j_blocksize);
-       sb->s_maxlen    = htonl(journal->j_maxlen);
-       sb->s_first     = htonl(1);
+       sb->s_blocksize = cpu_to_be32(journal->j_blocksize);
+       sb->s_maxlen    = cpu_to_be32(journal->j_maxlen);
+       sb->s_first     = cpu_to_be32(1);
 
        journal->j_transaction_sequence = 1;
 
@@ -861,7 +915,7 @@ int journal_create(journal_t *journal)
        return journal_reset(journal);
 }
 
-/** 
+/**
  * void journal_update_superblock() - Update journal sb on disk.
  * @journal: The journal to update.
  * @wait: Set to '0' if you don't want to wait for IO completion.
@@ -885,7 +939,7 @@ void journal_update_superblock(journal_t *journal, int wait)
                                journal->j_transaction_sequence) {
                jbd_debug(1,"JBD: Skipping superblock update on recovered sb "
                        "(start %ld, seq %d, errno %d)\n",
-                       journal->j_tail, journal->j_tail_sequence, 
+                       journal->j_tail, journal->j_tail_sequence,
                        journal->j_errno);
                goto out;
        }
@@ -894,9 +948,9 @@ void journal_update_superblock(journal_t *journal, int wait)
        jbd_debug(1,"JBD: updating superblock (start %ld, seq %d, errno %d)\n",
                  journal->j_tail, journal->j_tail_sequence, journal->j_errno);
 
-       sb->s_sequence = htonl(journal->j_tail_sequence);
-       sb->s_start    = htonl(journal->j_tail);
-       sb->s_errno    = htonl(journal->j_errno);
+       sb->s_sequence = cpu_to_be32(journal->j_tail_sequence);
+       sb->s_start    = cpu_to_be32(journal->j_tail);
+       sb->s_errno    = cpu_to_be32(journal->j_errno);
        spin_unlock(&journal->j_state_lock);
 
        BUFFER_TRACE(bh, "marking dirty");
@@ -904,7 +958,7 @@ void journal_update_superblock(journal_t *journal, int wait)
        if (wait)
                sync_dirty_buffer(bh);
        else
-               ll_rw_block(WRITE, 1, &bh);
+               ll_rw_block(SWRITE, 1, &bh);
 
 out:
        /* If we have just flushed the log (by marking s_start==0), then
@@ -947,13 +1001,13 @@ static int journal_get_superblock(journal_t *journal)
 
        err = -EINVAL;
 
-       if (sb->s_header.h_magic != htonl(JFS_MAGIC_NUMBER) ||
-           sb->s_blocksize != htonl(journal->j_blocksize)) {
+       if (sb->s_header.h_magic != cpu_to_be32(JFS_MAGIC_NUMBER) ||
+           sb->s_blocksize != cpu_to_be32(journal->j_blocksize)) {
                printk(KERN_WARNING "JBD: no valid journal superblock found\n");
                goto out;
        }
 
-       switch(ntohl(sb->s_header.h_blocktype)) {
+       switch(be32_to_cpu(sb->s_header.h_blocktype)) {
        case JFS_SUPERBLOCK_V1:
                journal->j_format_version = 1;
                break;
@@ -965,9 +1019,9 @@ static int journal_get_superblock(journal_t *journal)
                goto out;
        }
 
-       if (ntohl(sb->s_maxlen) < journal->j_maxlen)
-               journal->j_maxlen = ntohl(sb->s_maxlen);
-       else if (ntohl(sb->s_maxlen) > journal->j_maxlen) {
+       if (be32_to_cpu(sb->s_maxlen) < journal->j_maxlen)
+               journal->j_maxlen = be32_to_cpu(sb->s_maxlen);
+       else if (be32_to_cpu(sb->s_maxlen) > journal->j_maxlen) {
                printk (KERN_WARNING "JBD: journal file too short\n");
                goto out;
        }
@@ -995,11 +1049,11 @@ static int load_superblock(journal_t *journal)
 
        sb = journal->j_superblock;
 
-       journal->j_tail_sequence = ntohl(sb->s_sequence);
-       journal->j_tail = ntohl(sb->s_start);
-       journal->j_first = ntohl(sb->s_first);
-       journal->j_last = ntohl(sb->s_maxlen);
-       journal->j_errno = ntohl(sb->s_errno);
+       journal->j_tail_sequence = be32_to_cpu(sb->s_sequence);
+       journal->j_tail = be32_to_cpu(sb->s_start);
+       journal->j_first = be32_to_cpu(sb->s_first);
+       journal->j_last = be32_to_cpu(sb->s_maxlen);
+       journal->j_errno = be32_to_cpu(sb->s_errno);
 
        return 0;
 }
@@ -1008,7 +1062,7 @@ static int load_superblock(journal_t *journal)
 /**
  * int journal_load() - Read journal from disk.
  * @journal: Journal to act on.
- * 
+ *
  * Given a journal_t structure which tells us which disk blocks contain
  * a journal, read the journal from disk to initialise the in-memory
  * structures.
@@ -1016,17 +1070,17 @@ static int load_superblock(journal_t *journal)
 int journal_load(journal_t *journal)
 {
        int err;
+       journal_superblock_t *sb;
 
        err = load_superblock(journal);
        if (err)
                return err;
 
+       sb = journal->j_superblock;
        /* If this is a V2 superblock, then we have to check the
         * features flags on it. */
 
        if (journal->j_format_version >= 2) {
-               journal_superblock_t *sb = journal->j_superblock;
-
                if ((sb->s_feature_ro_compat &
                     ~cpu_to_be32(JFS_KNOWN_ROCOMPAT_FEATURES)) ||
                    (sb->s_feature_incompat &
@@ -1037,6 +1091,13 @@ int journal_load(journal_t *journal)
                }
        }
 
+       /*
+        * Create a slab for this blocksize
+        */
+       err = journal_create_jbd_slab(be32_to_cpu(sb->s_blocksize));
+       if (err)
+               return err;
+
        /* Let the recovery code check whether it needs to recover any
         * data from the journal. */
        if (journal_recover(journal))
@@ -1100,15 +1161,20 @@ void journal_destroy(journal_t *journal)
                iput(journal->j_inode);
        if (journal->j_revoke)
                journal_destroy_revoke(journal);
+       kfree(journal->j_wbuf);
        kfree(journal);
 }
 
 
 /**
  *int journal_check_used_features () - Check if features specified are used.
- * 
+ * @journal: Journal to check.
+ * @compat: bitmask of compatible features
+ * @ro: bitmask of features that force read-only mount
+ * @incompat: bitmask of incompatible features
+ *
  * Check whether the journal uses all of a given set of
- * features.  Return true (non-zero) if it does. 
+ * features.  Return true (non-zero) if it does.
  **/
 
 int journal_check_used_features (journal_t *journal, unsigned long compat,
@@ -1133,7 +1199,11 @@ int journal_check_used_features (journal_t *journal, unsigned long compat,
 
 /**
  * int journal_check_available_features() - Check feature set in journalling layer
- * 
+ * @journal: Journal to check.
+ * @compat: bitmask of compatible features
+ * @ro: bitmask of features that force read-only mount
+ * @incompat: bitmask of incompatible features
+ *
  * Check whether the journaling code supports the use of
  * all of a given set of features on this journal.  Return true
  * (non-zero) if it can. */
@@ -1165,9 +1235,13 @@ int journal_check_available_features (journal_t *journal, unsigned long compat,
 
 /**
  * int journal_set_features () - Mark a given journal feature in the superblock
+ * @journal: Journal to act on.
+ * @compat: bitmask of compatible features
+ * @ro: bitmask of features that force read-only mount
+ * @incompat: bitmask of incompatible features
  *
  * Mark a given journal feature as present on the
- * superblock.  Returns true if the requested features could be set. 
+ * superblock.  Returns true if the requested features could be set.
  *
  */
 
@@ -1197,6 +1271,7 @@ int journal_set_features (journal_t *journal, unsigned long compat,
 
 /**
  * int journal_update_format () - Update on-disk journal structure.
+ * @journal: Journal to act on.
  *
  * Given an initialised but unloaded journal struct, poke about in the
  * on-disk structure to update it to the most recent supported version.
@@ -1212,7 +1287,7 @@ int journal_update_format (journal_t *journal)
 
        sb = journal->j_superblock;
 
-       switch (ntohl(sb->s_header.h_blocktype)) {
+       switch (be32_to_cpu(sb->s_header.h_blocktype)) {
        case JFS_SUPERBLOCK_V2:
                return 0;
        case JFS_SUPERBLOCK_V1:
@@ -1234,7 +1309,7 @@ static int journal_convert_superblock_v1(journal_t *journal,
 
        /* Pre-initialise new fields to zero */
        offset = ((char *) &(sb->s_feature_compat)) - ((char *) sb);
-       blocksize = ntohl(sb->s_blocksize);
+       blocksize = be32_to_cpu(sb->s_blocksize);
        memset(&sb->s_feature_compat, 0, blocksize-offset);
 
        sb->s_nr_users = cpu_to_be32(1);
@@ -1252,7 +1327,7 @@ static int journal_convert_superblock_v1(journal_t *journal,
 /**
  * int journal_flush () - Flush journal
  * @journal: Journal to act on.
- * 
+ *
  * Flush all data for a given journal to disk and empty the journal.
  * Filesystems can use this when remounting readonly to ensure that
  * recovery does not need to happen on remount.
@@ -1319,7 +1394,7 @@ int journal_flush(journal_t *journal)
  * int journal_wipe() - Wipe journal contents
  * @journal: Journal to act on.
  * @write: flag (see below)
- * 
+ *
  * Wipe out all of the contents of a journal, safely.  This will produce
  * a warning if the journal contains any valid recovery information.
  * Must be called between journal_init_*() and journal_load().
@@ -1360,7 +1435,7 @@ int journal_wipe(journal_t *journal, int write)
  * device this journal is present.
  */
 
-const char *journal_dev_name(journal_t *journal, char *buffer)
+static const char *journal_dev_name(journal_t *journal, char *buffer)
 {
        struct block_device *bdev;
 
@@ -1374,7 +1449,7 @@ const char *journal_dev_name(journal_t *journal, char *buffer)
 
 /*
  * Journal abort has very specific semantics, which we describe
- * for journal abort. 
+ * for journal abort.
  *
  * Two internal function, which provide abort to te jbd layer
  * itself are here.
@@ -1406,7 +1481,7 @@ void __journal_abort_hard(journal_t *journal)
 
 /* Soft abort: record the abort error status in the journal superblock,
  * but don't do any other IO. */
-void __journal_abort_soft (journal_t *journal, int errno)
+static void __journal_abort_soft (journal_t *journal, int errno)
 {
        if (journal->j_flags & JFS_ABORT)
                return;
@@ -1429,7 +1504,7 @@ void __journal_abort_soft (journal_t *journal, int errno)
  * Perform a complete, immediate shutdown of the ENTIRE
  * journal (not of a single transaction).  This operation cannot be
  * undone without closing and reopening the journal.
- *           
+ *
  * The journal_abort function is intended to support higher level error
  * recovery mechanisms such as the ext2/ext3 remount-readonly error
  * mode.
@@ -1463,7 +1538,7 @@ void __journal_abort_soft (journal_t *journal, int errno)
  * supply an errno; a null errno implies that absolutely no further
  * writes are done to the journal (unless there are any already in
  * progress).
- * 
+ *
  */
 
 void journal_abort(journal_t *journal, int errno)
@@ -1471,7 +1546,7 @@ void journal_abort(journal_t *journal, int errno)
        __journal_abort_soft(journal, errno);
 }
 
-/** 
+/**
  * int journal_errno () - returns the journal's error state.
  * @journal: journal to examine.
  *
@@ -1495,8 +1570,9 @@ int journal_errno(journal_t *journal)
        return err;
 }
 
-/** 
+/**
  * int journal_clear_err () - clears the journal's error state
+ * @journal: journal to act on.
  *
  * An error must be cleared or Acked to take a FS out of readonly
  * mode.
@@ -1514,8 +1590,9 @@ int journal_clear_err(journal_t *journal)
        return err;
 }
 
-/** 
+/**
  * void journal_ack_err() - Ack journal err.
+ * @journal: journal to act on.
  *
  * An error must be cleared or Acked to take a FS out of readonly
  * mode.
@@ -1534,22 +1611,89 @@ int journal_blocks_per_page(struct inode *inode)
 }
 
 /*
- * Simple support for retying memory allocations.  Introduced to help to
- * debug different VM deadlock avoidance strategies. 
+ * Simple support for retrying memory allocations.  Introduced to help to
+ * debug different VM deadlock avoidance strategies.
  */
+void * __jbd_kmalloc (const char *where, size_t size, gfp_t flags, int retry)
+{
+       return kmalloc(size, flags | (retry ? __GFP_NOFAIL : 0));
+}
+
 /*
- * Simple support for retying memory allocations.  Introduced to help to
- * debug different VM deadlock avoidance strategies. 
+ * jbd slab management: create 1k, 2k, 4k, 8k slabs as needed
+ * and allocate frozen and commit buffers from these slabs.
+ *
+ * Reason for doing this is to avoid, SLAB_DEBUG - since it could
+ * cause bh to cross page boundary.
  */
-void * __jbd_kmalloc (const char *where, size_t size, int flags, int retry)
+
+#define JBD_MAX_SLABS 5
+#define JBD_SLAB_INDEX(size)  (size >> 11)
+
+static struct kmem_cache *jbd_slab[JBD_MAX_SLABS];
+static const char *jbd_slab_names[JBD_MAX_SLABS] = {
+       "jbd_1k", "jbd_2k", "jbd_4k", NULL, "jbd_8k"
+};
+
+static void journal_destroy_jbd_slabs(void)
 {
-       return kmalloc(size, flags | (retry ? __GFP_NOFAIL : 0));
+       int i;
+
+       for (i = 0; i < JBD_MAX_SLABS; i++) {
+               if (jbd_slab[i])
+                       kmem_cache_destroy(jbd_slab[i]);
+               jbd_slab[i] = NULL;
+       }
+}
+
+static int journal_create_jbd_slab(size_t slab_size)
+{
+       int i = JBD_SLAB_INDEX(slab_size);
+
+       BUG_ON(i >= JBD_MAX_SLABS);
+
+       /*
+        * Check if we already have a slab created for this size
+        */
+       if (jbd_slab[i])
+               return 0;
+
+       /*
+        * Create a slab and force alignment to be same as slabsize -
+        * this will make sure that allocations won't cross the page
+        * boundary.
+        */
+       jbd_slab[i] = kmem_cache_create(jbd_slab_names[i],
+                               slab_size, slab_size, 0, NULL, NULL);
+       if (!jbd_slab[i]) {
+               printk(KERN_EMERG "JBD: no memory for jbd_slab cache\n");
+               return -ENOMEM;
+       }
+       return 0;
+}
+
+void * jbd_slab_alloc(size_t size, gfp_t flags)
+{
+       int idx;
+
+       idx = JBD_SLAB_INDEX(size);
+       BUG_ON(jbd_slab[idx] == NULL);
+       return kmem_cache_alloc(jbd_slab[idx], flags | __GFP_NOFAIL);
+}
+
+void jbd_slab_free(void *ptr,  size_t size)
+{
+       int idx;
+
+       idx = JBD_SLAB_INDEX(size);
+       BUG_ON(jbd_slab[idx] == NULL);
+       kmem_cache_free(jbd_slab[idx], ptr);
 }
 
 /*
  * Journal_head storage management
  */
-static kmem_cache_t *journal_head_cache;
+static struct kmem_cache *journal_head_cache;
 #ifdef CONFIG_JBD_DEBUG
 static atomic_t nr_journal_heads = ATOMIC_INIT(0);
 #endif
@@ -1577,7 +1721,7 @@ static void journal_destroy_journal_head_cache(void)
 {
        J_ASSERT(journal_head_cache != NULL);
        kmem_cache_destroy(journal_head_cache);
-       journal_head_cache = 0;
+       journal_head_cache = NULL;
 }
 
 /*
@@ -1611,7 +1755,7 @@ static void journal_free_journal_head(struct journal_head *jh)
 {
 #ifdef CONFIG_JBD_DEBUG
        atomic_dec(&nr_journal_heads);
-       memset(jh, 0x5b, sizeof(*jh));
+       memset(jh, JBD_POISON_FREE, sizeof(*jh));
 #endif
        kmem_cache_free(journal_head_cache, jh);
 }
@@ -1726,6 +1870,7 @@ static void __journal_remove_journal_head(struct buffer_head *bh)
                if (jh->b_transaction == NULL &&
                                jh->b_next_transaction == NULL &&
                                jh->b_cp_transaction == NULL) {
+                       J_ASSERT_JH(jh, jh->b_jlist == BJ_None);
                        J_ASSERT_BH(bh, buffer_jbd(bh));
                        J_ASSERT_BH(bh, jh2bh(jh) == bh);
                        BUFFER_TRACE(bh, "remove journal_head");
@@ -1733,13 +1878,13 @@ static void __journal_remove_journal_head(struct buffer_head *bh)
                                printk(KERN_WARNING "%s: freeing "
                                                "b_frozen_data\n",
                                                __FUNCTION__);
-                               kfree(jh->b_frozen_data);
+                               jbd_slab_free(jh->b_frozen_data, bh->b_size);
                        }
                        if (jh->b_committed_data) {
                                printk(KERN_WARNING "%s: freeing "
                                                "b_committed_data\n",
                                                __FUNCTION__);
-                               kfree(jh->b_committed_data);
+                               jbd_slab_free(jh->b_committed_data, bh->b_size);
                        }
                        bh->b_private = NULL;
                        jh->b_bh = NULL;        /* debug, really */
@@ -1802,7 +1947,7 @@ EXPORT_SYMBOL(journal_enable_debug);
 
 static struct proc_dir_entry *proc_jbd_debug;
 
-int read_jbd_debug(char *page, char **start, off_t off,
+static int read_jbd_debug(char *page, char **start, off_t off,
                          int count, int *eof, void *data)
 {
        int ret;
@@ -1812,7 +1957,7 @@ int read_jbd_debug(char *page, char **start, off_t off,
        return ret;
 }
 
-int write_jbd_debug(struct file *file, const char __user *buffer,
+static int write_jbd_debug(struct file *file, const char __user *buffer,
                           unsigned long count, void *data)
 {
        char buf[32];
@@ -1851,7 +1996,7 @@ static void __exit remove_jbd_proc_entry(void)
 
 #endif
 
-kmem_cache_t *jbd_handle_cache;
+struct kmem_cache *jbd_handle_cache;
 
 static int __init journal_init_handle_cache(void)
 {
@@ -1895,12 +2040,15 @@ static void journal_destroy_caches(void)
        journal_destroy_revoke_caches();
        journal_destroy_journal_head_cache();
        journal_destroy_handle_cache();
+       journal_destroy_jbd_slabs();
 }
 
 static int __init journal_init(void)
 {
        int ret;
 
+       BUILD_BUG_ON(sizeof(struct journal_superblock_s) != 1024);
+
        ret = journal_init_caches();
        if (ret != 0)
                journal_destroy_caches();