These changes are the raw update to linux-4.4.6-rt14. Kernel sources

are taken from kernel.org, and rt patch from the rt wiki download page.

During the rebasing, the following patch collided:

Force tick interrupt and get rid of softirq magic(I70131fb85).

Collisions have been removed because its logic was found on the
source already.

Change-Id: I7f57a4081d9deaa0d9ccfc41a6c8daccdee3b769
Signed-off-by: José Pekkarinen <jose.pekkarinen@nokia.com>

1 files changed, 0 insertions, 2145 deletions

diff --git a/kernel/fs/jbd/journal.c b/kernel/fs/jbd/journal.c
deleted file mode 100644
index c46a79adb..000000000
--- a/kernel/fs/jbd/journal.c
+++ /dev/null
@@ -1,2145 +0,0 @@
-/*
- * linux/fs/jbd/journal.c
- *
- * Written by Stephen C. Tweedie <sct@redhat.com>, 1998
- *
- * Copyright 1998 Red Hat corp --- All Rights Reserved
- *
- * This file is part of the Linux kernel and is made available under
- * the terms of the GNU General Public License, version 2, or at your
- * option, any later version, incorporated herein by reference.
- *
- * Generic filesystem journal-writing code; part of the ext2fs
- * journaling system.
- *
- * This file manages journals: areas of disk reserved for logging
- * transactional updates.  This includes the kernel journaling thread
- * which is responsible for scheduling updates to the log.
- *
- * We do not actually manage the physical storage of the journal in this
- * file: that is left to a per-journal policy function, which allows us
- * to store the journal within a filesystem-specified area for ext2
- * journaling (ext2 can use a reserved inode for storing the log).
- */
-
-#include <linux/module.h>
-#include <linux/time.h>
-#include <linux/fs.h>
-#include <linux/jbd.h>
-#include <linux/errno.h>
-#include <linux/slab.h>
-#include <linux/init.h>
-#include <linux/mm.h>
-#include <linux/freezer.h>
-#include <linux/pagemap.h>
-#include <linux/kthread.h>
-#include <linux/poison.h>
-#include <linux/proc_fs.h>
-#include <linux/debugfs.h>
-#include <linux/ratelimit.h>
-
-#define CREATE_TRACE_POINTS
-#include <trace/events/jbd.h>
-
-#include <asm/uaccess.h>
-#include <asm/page.h>
-
-EXPORT_SYMBOL(journal_start);
-EXPORT_SYMBOL(journal_restart);
-EXPORT_SYMBOL(journal_extend);
-EXPORT_SYMBOL(journal_stop);
-EXPORT_SYMBOL(journal_lock_updates);
-EXPORT_SYMBOL(journal_unlock_updates);
-EXPORT_SYMBOL(journal_get_write_access);
-EXPORT_SYMBOL(journal_get_create_access);
-EXPORT_SYMBOL(journal_get_undo_access);
-EXPORT_SYMBOL(journal_dirty_data);
-EXPORT_SYMBOL(journal_dirty_metadata);
-EXPORT_SYMBOL(journal_release_buffer);
-EXPORT_SYMBOL(journal_forget);
-#if 0
-EXPORT_SYMBOL(journal_sync_buffer);
-#endif
-EXPORT_SYMBOL(journal_flush);
-EXPORT_SYMBOL(journal_revoke);
-
-EXPORT_SYMBOL(journal_init_dev);
-EXPORT_SYMBOL(journal_init_inode);
-EXPORT_SYMBOL(journal_update_format);
-EXPORT_SYMBOL(journal_check_used_features);
-EXPORT_SYMBOL(journal_check_available_features);
-EXPORT_SYMBOL(journal_set_features);
-EXPORT_SYMBOL(journal_create);
-EXPORT_SYMBOL(journal_load);
-EXPORT_SYMBOL(journal_destroy);
-EXPORT_SYMBOL(journal_abort);
-EXPORT_SYMBOL(journal_errno);
-EXPORT_SYMBOL(journal_ack_err);
-EXPORT_SYMBOL(journal_clear_err);
-EXPORT_SYMBOL(log_wait_commit);
-EXPORT_SYMBOL(log_start_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_force_commit);
-
-static int journal_convert_superblock_v1(journal_t *, journal_superblock_t *);
-static void __journal_abort_soft (journal_t *journal, int errno);
-static const char *journal_dev_name(journal_t *journal, char *buffer);
-
-#ifdef CONFIG_JBD_DEBUG
-void __jbd_debug(int level, const char *file, const char *func,
-		 unsigned int line, const char *fmt, ...)
-{
-	struct va_format vaf;
-	va_list args;
-
-	if (level > journal_enable_debug)
-		return;
-	va_start(args, fmt);
-	vaf.fmt = fmt;
-	vaf.va = &args;
-	printk(KERN_DEBUG "%s: (%s, %u): %pV\n", file, func, line, &vaf);
-	va_end(args);
-}
-EXPORT_SYMBOL(__jbd_debug);
-#endif
-
-/*
- * Helper function used to manage commit timeouts
- */
-
-static void commit_timeout(unsigned long __data)
-{
-	struct task_struct * p = (struct task_struct *) __data;
-
-	wake_up_process(p);
-}
-
-/*
- * kjournald: The main thread function used to manage a logging device
- * journal.
- *
- * This kernel thread is responsible for two things:
- *
- * 1) COMMIT:  Every so often we need to commit the current state of the
- *    filesystem to disk.  The journal thread is responsible for writing
- *    all of the metadata buffers to disk.
- *
- * 2) CHECKPOINT: We cannot reuse a used section of the log file until all
- *    of the data in that part of the log has been rewritten elsewhere on
- *    the disk.  Flushing these old buffers to reclaim space in the log is
- *    known as checkpointing, and this thread is responsible for that job.
- */
-
-static int kjournald(void *arg)
-{
-	journal_t *journal = arg;
-	transaction_t *transaction;
-
-	/*
-	 * 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);
-
-	set_freezable();
-
-	/* Record that the journal thread is running */
-	journal->j_task = current;
-	wake_up(&journal->j_wait_done_commit);
-
-	printk(KERN_INFO "kjournald starting.  Commit interval %ld seconds\n",
-			journal->j_commit_interval / HZ);
-
-	/*
-	 * And now, wait forever for commit wakeup events.
-	 */
-	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);
-		journal_commit_transaction(journal);
-		spin_lock(&journal->j_state_lock);
-		goto loop;
-	}
-
-	wake_up(&journal->j_wait_done_commit);
-	if (freezing(current)) {
-		/*
-		 * The simpler the better. Flushing journal isn't a
-		 * good idea, because that depends on threads that may
-		 * be already stopped.
-		 */
-		jbd_debug(1, "Now suspending kjournald\n");
-		spin_unlock(&journal->j_state_lock);
-		try_to_freeze();
-		spin_lock(&journal->j_state_lock);
-	} else {
-		/*
-		 * We assume on resume that commits are already there,
-		 * so we don't sleep
-		 */
-		DEFINE_WAIT(wait);
-		int should_sleep = 1;
-
-		prepare_to_wait(&journal->j_wait_commit, &wait,
-				TASK_INTERRUPTIBLE);
-		if (journal->j_commit_sequence != journal->j_commit_request)
-			should_sleep = 0;
-		transaction = journal->j_running_transaction;
-		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();
-			spin_lock(&journal->j_state_lock);
-		}
-		finish_wait(&journal->j_wait_commit, &wait);
-	}
-
-	jbd_debug(1, "kjournald wakes\n");
-
-	/*
-	 * Were we woken up by a commit wakeup event?
-	 */
-	transaction = journal->j_running_transaction;
-	if (transaction && time_after_eq(jiffies, transaction->t_expires)) {
-		journal->j_commit_request = transaction->t_tid;
-		jbd_debug(1, "woke because of timeout\n");
-	}
-	goto loop;
-
-end_loop:
-	spin_unlock(&journal->j_state_lock);
-	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");
-	return 0;
-}
-
-static int journal_start_thread(journal_t *journal)
-{
-	struct task_struct *t;
-
-	t = kthread_run(kjournald, journal, "kjournald");
-	if (IS_ERR(t))
-		return PTR_ERR(t);
-
-	wait_event(journal->j_wait_done_commit, journal->j_task != NULL);
-	return 0;
-}
-
-static void journal_kill_thread(journal_t *journal)
-{
-	spin_lock(&journal->j_state_lock);
-	journal->j_flags |= JFS_UNMOUNT;
-
-	while (journal->j_task) {
-		wake_up(&journal->j_wait_commit);
-		spin_unlock(&journal->j_state_lock);
-		wait_event(journal->j_wait_done_commit,
-				journal->j_task == NULL);
-		spin_lock(&journal->j_state_lock);
-	}
-	spin_unlock(&journal->j_state_lock);
-}
-
-/*
- * journal_write_metadata_buffer: write a metadata buffer to the journal.
- *
- * Writes a metadata buffer to a given disk block.  The actual IO is not
- * performed but a new buffer_head is constructed which labels the data
- * to be written with the correct destination disk block.
- *
- * Any magic-number escaping which needs to be done will cause a
- * copy-out here.  If the buffer happens to start with the
- * JFS_MAGIC_NUMBER, then we can't write it to the log directly: the
- * magic number is only written to the log for descripter blocks.  In
- * this case, we copy the data and replace the first word with 0, and we
- * return a result code which indicates that this buffer needs to be
- * marked as an escaped buffer in the corresponding log descriptor
- * block.  The missing word can then be restored when the block is read
- * during recovery.
- *
- * If the source buffer has already been modified by a new transaction
- * since we took the last commit snapshot, we use the frozen copy of
- * that data for IO.  If we end up using the existing buffer_head's data
- * for the write, then we *have* to lock the buffer to prevent anyone
- * else from using and possibly modifying it while the IO is in
- * progress.
- *
- * The function returns a pointer to the buffer_heads to be used for IO.
- *
- * We assume that the journal has already been locked in this function.
- *
- * Return value:
- *  <0: Error
- * >=0: Finished OK
- *
- * On success:
- * Bit 0 set == escape performed on the data
- * Bit 1 set == buffer copy-out performed (kfree the data after IO)
- */
-
-int journal_write_metadata_buffer(transaction_t *transaction,
-				  struct journal_head  *jh_in,
-				  struct journal_head **jh_out,
-				  unsigned int blocknr)
-{
-	int need_copy_out = 0;
-	int done_copy_out = 0;
-	int do_escape = 0;
-	char *mapped_data;
-	struct buffer_head *new_bh;
-	struct journal_head *new_jh;
-	struct page *new_page;
-	unsigned int new_offset;
-	struct buffer_head *bh_in = jh2bh(jh_in);
-	journal_t *journal = transaction->t_journal;
-
-	/*
-	 * The buffer really shouldn't be locked: only the current committing
-	 * transaction is allowed to write it, so nobody else is allowed
-	 * to do any IO.
-	 *
-	 * akpm: except if we're journalling data, and write() output is
-	 * also part of a shared mapping, and another thread has
-	 * decided to launch a writepage() against this buffer.
-	 */
-	J_ASSERT_BH(bh_in, buffer_jbddirty(bh_in));
-
-	new_bh = alloc_buffer_head(GFP_NOFS|__GFP_NOFAIL);
-	/* keep subsequent assertions sane */
-	atomic_set(&new_bh->b_count, 1);
-	new_jh = journal_add_journal_head(new_bh);	/* This sleeps */
-
-	/*
-	 * If a new transaction has already done a buffer copy-out, then
-	 * we use that version of the data for the commit.
-	 */
-	jbd_lock_bh_state(bh_in);
-repeat:
-	if (jh_in->b_frozen_data) {
-		done_copy_out = 1;
-		new_page = virt_to_page(jh_in->b_frozen_data);
-		new_offset = offset_in_page(jh_in->b_frozen_data);
-	} else {
-		new_page = jh2bh(jh_in)->b_page;
-		new_offset = offset_in_page(jh2bh(jh_in)->b_data);
-	}
-
-	mapped_data = kmap_atomic(new_page);
-	/*
-	 * Check for escaping
-	 */
-	if (*((__be32 *)(mapped_data + new_offset)) ==
-				cpu_to_be32(JFS_MAGIC_NUMBER)) {
-		need_copy_out = 1;
-		do_escape = 1;
-	}
-	kunmap_atomic(mapped_data);
-
-	/*
-	 * Do we need to do a data copy?
-	 */
-	if (need_copy_out && !done_copy_out) {
-		char *tmp;
-
-		jbd_unlock_bh_state(bh_in);
-		tmp = jbd_alloc(bh_in->b_size, GFP_NOFS);
-		jbd_lock_bh_state(bh_in);
-		if (jh_in->b_frozen_data) {
-			jbd_free(tmp, bh_in->b_size);
-			goto repeat;
-		}
-
-		jh_in->b_frozen_data = tmp;
-		mapped_data = kmap_atomic(new_page);
-		memcpy(tmp, mapped_data + new_offset, jh2bh(jh_in)->b_size);
-		kunmap_atomic(mapped_data);
-
-		new_page = virt_to_page(tmp);
-		new_offset = offset_in_page(tmp);
-		done_copy_out = 1;
-	}
-
-	/*
-	 * Did we need to do an escaping?  Now we've done all the
-	 * copying, we can finally do so.
-	 */
-	if (do_escape) {
-		mapped_data = kmap_atomic(new_page);
-		*((unsigned int *)(mapped_data + new_offset)) = 0;
-		kunmap_atomic(mapped_data);
-	}
-
-	set_bh_page(new_bh, new_page, new_offset);
-	new_jh->b_transaction = NULL;
-	new_bh->b_size = jh2bh(jh_in)->b_size;
-	new_bh->b_bdev = transaction->t_journal->j_dev;
-	new_bh->b_blocknr = blocknr;
-	set_buffer_mapped(new_bh);
-	set_buffer_dirty(new_bh);
-
-	*jh_out = new_jh;
-
-	/*
-	 * The to-be-written buffer needs to get moved to the io queue,
-	 * and the original buffer whose contents we are shadowing or
-	 * copying is moved to the transaction's shadow queue.
-	 */
-	JBUFFER_TRACE(jh_in, "file as BJ_Shadow");
-	spin_lock(&journal->j_list_lock);
-	__journal_file_buffer(jh_in, transaction, BJ_Shadow);
-	spin_unlock(&journal->j_list_lock);
-	jbd_unlock_bh_state(bh_in);
-
-	JBUFFER_TRACE(new_jh, "file as BJ_IO");
-	journal_file_buffer(new_jh, transaction, BJ_IO);
-
-	return do_escape | (done_copy_out << 1);
-}
-
-/*
- * Allocation code for the journal file.  Manage the space left in the
- * journal, so that we can begin checkpointing when appropriate.
- */
-
-/*
- * __log_space_left: Return the number of free blocks left in the journal.
- *
- * Called with the journal already locked.
- *
- * Called under j_state_lock
- */
-
-int __log_space_left(journal_t *journal)
-{
-	int left = journal->j_free;
-
-	assert_spin_locked(&journal->j_state_lock);
-
-	/*
-	 * Be pessimistic here about the number of those free blocks which
-	 * might be required for log descriptor control blocks.
-	 */
-
-#define MIN_LOG_RESERVED_BLOCKS 32 /* Allow for rounding errors */
-
-	left -= MIN_LOG_RESERVED_BLOCKS;
-
-	if (left <= 0)
-		return 0;
-	left -= (left >> 3);
-	return left;
-}
-
-/*
- * Called under j_state_lock.  Returns true if a transaction commit was started.
- */
-int __log_start_commit(journal_t *journal, tid_t target)
-{
-	/*
-	 * The only transaction we can possibly wait upon is the
-	 * currently running transaction (if it exists).  Otherwise,
-	 * the target tid must be an old one.
-	 */
-	if (journal->j_commit_request != target &&
-	    journal->j_running_transaction &&
-	    journal->j_running_transaction->t_tid == target) {
-		/*
-		 * We want a new commit: OK, mark the request and wakeup the
-		 * commit thread.  We do _not_ do the commit ourselves.
-		 */
-
-		journal->j_commit_request = target;
-		jbd_debug(1, "JBD: requesting commit %d/%d\n",
-			  journal->j_commit_request,
-			  journal->j_commit_sequence);
-		wake_up(&journal->j_wait_commit);
-		return 1;
-	} else if (!tid_geq(journal->j_commit_request, target))
-		/* This should never happen, but if it does, preserve
-		   the evidence before kjournald goes into a loop and
-		   increments j_commit_sequence beyond all recognition. */
-		WARN_ONCE(1, "jbd: bad log_start_commit: %u %u %u %u\n",
-		    journal->j_commit_request, journal->j_commit_sequence,
-		    target, journal->j_running_transaction ?
-		    journal->j_running_transaction->t_tid : 0);
-	return 0;
-}
-
-int log_start_commit(journal_t *journal, tid_t tid)
-{
-	int ret;
-
-	spin_lock(&journal->j_state_lock);
-	ret = __log_start_commit(journal, tid);
-	spin_unlock(&journal->j_state_lock);
-	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 is going to be committed (or is currently already
- * committing), and fills its tid in at *ptid
- */
-int journal_start_commit(journal_t *journal, tid_t *ptid)
-{
-	int ret = 0;
-
-	spin_lock(&journal->j_state_lock);
-	if (journal->j_running_transaction) {
-		tid_t tid = journal->j_running_transaction->t_tid;
-
-		__log_start_commit(journal, tid);
-		/* There's a running transaction and we've just made sure
-		 * it's commit has been scheduled. */
-		if (ptid)
-			*ptid = tid;
-		ret = 1;
-	} else if (journal->j_committing_transaction) {
-		/*
-		 * If commit has been started, then we have to wait for
-		 * completion of that transaction.
-		 */
-		if (ptid)
-			*ptid = journal->j_committing_transaction->t_tid;
-		ret = 1;
-	}
-	spin_unlock(&journal->j_state_lock);
-	return ret;
-}
-
-/*
- * Wait for a specified commit to complete.
- * The caller may not hold the journal lock.
- */
-int log_wait_commit(journal_t *journal, tid_t tid)
-{
-	int err = 0;
-
-#ifdef CONFIG_JBD_DEBUG
-	spin_lock(&journal->j_state_lock);
-	if (!tid_geq(journal->j_commit_request, tid)) {
-		printk(KERN_ERR
-		       "%s: error: j_commit_request=%d, tid=%d\n",
-		       __func__, journal->j_commit_request, tid);
-	}
-	spin_unlock(&journal->j_state_lock);
-#endif
-	spin_lock(&journal->j_state_lock);
-	/*
-	 * Not running or committing trans? Must be already committed. This
-	 * saves us from waiting for a *long* time when tid overflows.
-	 */
-	if (!((journal->j_running_transaction &&
-	       journal->j_running_transaction->t_tid == tid) ||
-	      (journal->j_committing_transaction &&
-	       journal->j_committing_transaction->t_tid == tid)))
-		goto out_unlock;
-
-	if (!tid_geq(journal->j_commit_waited, tid))
-		journal->j_commit_waited = tid;
-	while (tid_gt(tid, journal->j_commit_sequence)) {
-		jbd_debug(1, "JBD: want %d, j_commit_sequence=%d\n",
-				  tid, journal->j_commit_sequence);
-		wake_up(&journal->j_wait_commit);
-		spin_unlock(&journal->j_state_lock);
-		wait_event(journal->j_wait_done_commit,
-				!tid_gt(tid, journal->j_commit_sequence));
-		spin_lock(&journal->j_state_lock);
-	}
-out_unlock:
-	spin_unlock(&journal->j_state_lock);
-
-	if (unlikely(is_journal_aborted(journal)))
-		err = -EIO;
-	return err;
-}
-
-/*
- * Return 1 if a given transaction has not yet sent barrier request
- * connected with a transaction commit. If 0 is returned, transaction
- * may or may not have sent the barrier. Used to avoid sending barrier
- * twice in common cases.
- */
-int journal_trans_will_send_data_barrier(journal_t *journal, tid_t tid)
-{
-	int ret = 0;
-	transaction_t *commit_trans;
-
-	if (!(journal->j_flags & JFS_BARRIER))
-		return 0;
-	spin_lock(&journal->j_state_lock);
-	/* Transaction already committed? */
-	if (tid_geq(journal->j_commit_sequence, tid))
-		goto out;
-	/*
-	 * Transaction is being committed and we already proceeded to
-	 * writing commit record?
-	 */
-	commit_trans = journal->j_committing_transaction;
-	if (commit_trans && commit_trans->t_tid == tid &&
-	    commit_trans->t_state >= T_COMMIT_RECORD)
-		goto out;
-	ret = 1;
-out:
-	spin_unlock(&journal->j_state_lock);
-	return ret;
-}
-EXPORT_SYMBOL(journal_trans_will_send_data_barrier);
-
-/*
- * Log buffer allocation routines:
- */
-
-int journal_next_log_block(journal_t *journal, unsigned int *retp)
-{
-	unsigned int blocknr;
-
-	spin_lock(&journal->j_state_lock);
-	J_ASSERT(journal->j_free > 1);
-
-	blocknr = journal->j_head;
-	journal->j_head++;
-	journal->j_free--;
-	if (journal->j_head == journal->j_last)
-		journal->j_head = journal->j_first;
-	spin_unlock(&journal->j_state_lock);
-	return journal_bmap(journal, blocknr, retp);
-}
-
-/*
- * Conversion of logical to physical block numbers for the journal
- *
- * On external journals the journal blocks are identity-mapped, so
- * this is a no-op.  If needed, we can use j_blk_offset - everything is
- * ready.
- */
-int journal_bmap(journal_t *journal, unsigned int blocknr,
-		 unsigned int *retp)
-{
-	int err = 0;
-	unsigned int ret;
-
-	if (journal->j_inode) {
-		ret = bmap(journal->j_inode, blocknr);
-		if (ret)
-			*retp = ret;
-		else {
-			char b[BDEVNAME_SIZE];
-
-			printk(KERN_ALERT "%s: journal block not found "
-					"at offset %u on %s\n",
-				__func__,
-				blocknr,
-				bdevname(journal->j_dev, b));
-			err = -EIO;
-			__journal_abort_soft(journal, err);
-		}
-	} else {
-		*retp = blocknr; /* +journal->j_blk_offset */
-	}
-	return err;
-}
-
-/*
- * 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 buffer_head *bh;
-	unsigned int blocknr;
-	int err;
-
-	err = journal_next_log_block(journal, &blocknr);
-
-	if (err)
-		return NULL;
-
-	bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize);
-	if (!bh)
-		return NULL;
-	lock_buffer(bh);
-	memset(bh->b_data, 0, journal->j_blocksize);
-	set_buffer_uptodate(bh);
-	unlock_buffer(bh);
-	BUFFER_TRACE(bh, "return this buffer");
-	return journal_add_journal_head(bh);
-}
-
-/*
- * Management for journal control blocks: functions to create and
- * destroy journal_t structures, and to initialise and read existing
- * journal blocks from disk.  */
-
-/* First: create and setup a journal_t object in memory.  We initialise
- * very few fields yet: that has to wait until we have created the
- * journal structures from from scratch, or loaded them from disk. */
-
-static journal_t * journal_init_common (void)
-{
-	journal_t *journal;
-	int err;
-
-	journal = kzalloc(sizeof(*journal), GFP_KERNEL);
-	if (!journal)
-		goto fail;
-
-	init_waitqueue_head(&journal->j_wait_transaction_locked);
-	init_waitqueue_head(&journal->j_wait_logspace);
-	init_waitqueue_head(&journal->j_wait_done_commit);
-	init_waitqueue_head(&journal->j_wait_checkpoint);
-	init_waitqueue_head(&journal->j_wait_commit);
-	init_waitqueue_head(&journal->j_wait_updates);
-	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);
-
-	journal->j_commit_interval = (HZ * JBD_DEFAULT_MAX_COMMIT_AGE);
-
-	/* The journal is marked for error until we succeed with recovery! */
-	journal->j_flags = JFS_ABORT;
-
-	/* Set up a default-sized revoke table for the new mount. */
-	err = journal_init_revoke(journal, JOURNAL_REVOKE_DEFAULT_HASH);
-	if (err) {
-		kfree(journal);
-		goto fail;
-	}
-	return journal;
-fail:
-	return NULL;
-}
-
-/* journal_init_dev and journal_init_inode:
- *
- * Create a journal structure assigned some fixed set of disk blocks to
- * the journal.  We don't actually touch those disk blocks yet, but we
- * need to set up all of the mapping information to tell the journaling
- * system where the journal blocks are.
- *
- */
-
-/**
- *  journal_t * journal_init_dev() - creates and initialises a journal structure
- *  @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:  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,
-			int start, int len, int blocksize)
-{
-	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: Can't allocate bhs for commit thread\n",
-			__func__);
-		goto out_err;
-	}
-	journal->j_dev = bdev;
-	journal->j_fs_dev = fs_dev;
-	journal->j_blk_offset = start;
-	journal->j_maxlen = len;
-
-	bh = __getblk(journal->j_dev, start, journal->j_blocksize);
-	if (!bh) {
-		printk(KERN_ERR
-		       "%s: Cannot get buffer for journal superblock\n",
-		       __func__);
-		goto out_err;
-	}
-	journal->j_sb_buffer = bh;
-	journal->j_superblock = (journal_superblock_t *)bh->b_data;
-
-	return journal;
-out_err:
-	kfree(journal->j_wbuf);
-	kfree(journal);
-	return NULL;
-}
-
-/**
- *  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.
- */
-journal_t * journal_init_inode (struct inode *inode)
-{
-	struct buffer_head *bh;
-	journal_t *journal = journal_init_common();
-	int err;
-	int n;
-	unsigned int blocknr;
-
-	if (!journal)
-		return NULL;
-
-	journal->j_dev = journal->j_fs_dev = inode->i_sb->s_bdev;
-	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,
-		  (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: Can't allocate bhs for commit thread\n",
-			__func__);
-		goto out_err;
-	}
-
-	err = journal_bmap(journal, 0, &blocknr);
-	/* If that failed, give up */
-	if (err) {
-		printk(KERN_ERR "%s: Cannot locate journal superblock\n",
-		       __func__);
-		goto out_err;
-	}
-
-	bh = getblk_unmovable(journal->j_dev, blocknr, journal->j_blocksize);
-	if (!bh) {
-		printk(KERN_ERR
-		       "%s: Cannot get buffer for journal superblock\n",
-		       __func__);
-		goto out_err;
-	}
-	journal->j_sb_buffer = bh;
-	journal->j_superblock = (journal_superblock_t *)bh->b_data;
-
-	return journal;
-out_err:
-	kfree(journal->j_wbuf);
-	kfree(journal);
-	return NULL;
-}
-
-/*
- * 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.
- */
-static void journal_fail_superblock (journal_t *journal)
-{
-	struct buffer_head *bh = journal->j_sb_buffer;
-	brelse(bh);
-	journal->j_sb_buffer = NULL;
-}
-
-/*
- * Given a journal_t structure, initialise the various fields for
- * startup of a new journaling session.  We use this both when creating
- * a journal, and after recovering an old journal to reset it for
- * subsequent use.
- */
-
-static int journal_reset(journal_t *journal)
-{
-	journal_superblock_t *sb = journal->j_superblock;
-	unsigned int first, last;
-
-	first = be32_to_cpu(sb->s_first);
-	last = be32_to_cpu(sb->s_maxlen);
-	if (first + JFS_MIN_JOURNAL_BLOCKS > last + 1) {
-		printk(KERN_ERR "JBD: Journal too short (blocks %u-%u).\n",
-		       first, last);
-		journal_fail_superblock(journal);
-		return -EINVAL;
-	}
-
-	journal->j_first = first;
-	journal->j_last = last;
-
-	journal->j_head = first;
-	journal->j_tail = first;
-	journal->j_free = last - first;
-
-	journal->j_tail_sequence = journal->j_transaction_sequence;
-	journal->j_commit_sequence = journal->j_transaction_sequence - 1;
-	journal->j_commit_request = journal->j_commit_sequence;
-
-	journal->j_max_transaction_buffers = journal->j_maxlen / 4;
-
-	/*
-	 * As a special case, if the on-disk copy is already marked as needing
-	 * no recovery (s_start == 0), then we can safely defer the superblock
-	 * update until the next commit by setting JFS_FLUSHED.  This avoids
-	 * attempting a write to a potential-readonly device.
-	 */
-	if (sb->s_start == 0) {
-		jbd_debug(1,"JBD: Skipping superblock update on recovered sb "
-			"(start %u, seq %d, errno %d)\n",
-			journal->j_tail, journal->j_tail_sequence,
-			journal->j_errno);
-		journal->j_flags |= JFS_FLUSHED;
-	} else {
-		/* Lock here to make assertions happy... */
-		mutex_lock(&journal->j_checkpoint_mutex);
-		/*
-		 * Update log tail information. We use WRITE_FUA since new
-		 * transaction will start reusing journal space and so we
-		 * must make sure information about current log tail is on
-		 * disk before that.
-		 */
-		journal_update_sb_log_tail(journal,
-					   journal->j_tail_sequence,
-					   journal->j_tail,
-					   WRITE_FUA);
-		mutex_unlock(&journal->j_checkpoint_mutex);
-	}
-	return journal_start_thread(journal);
-}
-
-/**
- * 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.
- **/
-int journal_create(journal_t *journal)
-{
-	unsigned int blocknr;
-	struct buffer_head *bh;
-	journal_superblock_t *sb;
-	int i, err;
-
-	if (journal->j_maxlen < JFS_MIN_JOURNAL_BLOCKS) {
-		printk (KERN_ERR "Journal length (%d blocks) too short.\n",
-			journal->j_maxlen);
-		journal_fail_superblock(journal);
-		return -EINVAL;
-	}
-
-	if (journal->j_inode == NULL) {
-		/*
-		 * We don't know what block to start at!
-		 */
-		printk(KERN_EMERG
-		       "%s: creation of journal on external device!\n",
-		       __func__);
-		BUG();
-	}
-
-	/* Zero out the entire journal on disk.  We cannot afford to
-	   have any blocks on disk beginning with JFS_MAGIC_NUMBER. */
-	jbd_debug(1, "JBD: Zeroing out journal blocks...\n");
-	for (i = 0; i < journal->j_maxlen; i++) {
-		err = journal_bmap(journal, i, &blocknr);
-		if (err)
-			return err;
-		bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize);
-		if (unlikely(!bh))
-			return -ENOMEM;
-		lock_buffer(bh);
-		memset (bh->b_data, 0, journal->j_blocksize);
-		BUFFER_TRACE(bh, "marking dirty");
-		mark_buffer_dirty(bh);
-		BUFFER_TRACE(bh, "marking uptodate");
-		set_buffer_uptodate(bh);
-		unlock_buffer(bh);
-		__brelse(bh);
-	}
-
-	sync_blockdev(journal->j_dev);
-	jbd_debug(1, "JBD: journal cleared.\n");
-
-	/* OK, fill in the initial static fields in the new superblock */
-	sb = journal->j_superblock;
-
-	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	= 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;
-
-	journal->j_flags &= ~JFS_ABORT;
-	journal->j_format_version = 2;
-
-	return journal_reset(journal);
-}
-
-static void journal_write_superblock(journal_t *journal, int write_op)
-{
-	struct buffer_head *bh = journal->j_sb_buffer;
-	int ret;
-
-	trace_journal_write_superblock(journal, write_op);
-	if (!(journal->j_flags & JFS_BARRIER))
-		write_op &= ~(REQ_FUA | REQ_FLUSH);
-	lock_buffer(bh);
-	if (buffer_write_io_error(bh)) {
-		char b[BDEVNAME_SIZE];
-		/*
-		 * Oh, dear.  A previous attempt to write the journal
-		 * superblock failed.  This could happen because the
-		 * USB device was yanked out.  Or it could happen to
-		 * be a transient write error and maybe the block will
-		 * be remapped.  Nothing we can do but to retry the
-		 * write and hope for the best.
-		 */
-		printk(KERN_ERR "JBD: previous I/O error detected "
-		       "for journal superblock update for %s.\n",
-		       journal_dev_name(journal, b));
-		clear_buffer_write_io_error(bh);
-		set_buffer_uptodate(bh);
-	}
-
-	get_bh(bh);
-	bh->b_end_io = end_buffer_write_sync;
-	ret = submit_bh(write_op, bh);
-	wait_on_buffer(bh);
-	if (buffer_write_io_error(bh)) {
-		clear_buffer_write_io_error(bh);
-		set_buffer_uptodate(bh);
-		ret = -EIO;
-	}
-	if (ret) {
-		char b[BDEVNAME_SIZE];
-		printk(KERN_ERR "JBD: Error %d detected "
-		       "when updating journal superblock for %s.\n",
-		       ret, journal_dev_name(journal, b));
-	}
-}
-
-/**
- * journal_update_sb_log_tail() - Update log tail in journal sb on disk.
- * @journal: The journal to update.
- * @tail_tid: TID of the new transaction at the tail of the log
- * @tail_block: The first block of the transaction at the tail of the log
- * @write_op: With which operation should we write the journal sb
- *
- * Update a journal's superblock information about log tail and write it to
- * disk, waiting for the IO to complete.
- */
-void journal_update_sb_log_tail(journal_t *journal, tid_t tail_tid,
-				unsigned int tail_block, int write_op)
-{
-	journal_superblock_t *sb = journal->j_superblock;
-
-	BUG_ON(!mutex_is_locked(&journal->j_checkpoint_mutex));
-	jbd_debug(1,"JBD: updating superblock (start %u, seq %u)\n",
-		  tail_block, tail_tid);
-
-	sb->s_sequence = cpu_to_be32(tail_tid);
-	sb->s_start    = cpu_to_be32(tail_block);
-
-	journal_write_superblock(journal, write_op);
-
-	/* Log is no longer empty */
-	spin_lock(&journal->j_state_lock);
-	WARN_ON(!sb->s_sequence);
-	journal->j_flags &= ~JFS_FLUSHED;
-	spin_unlock(&journal->j_state_lock);
-}
-
-/**
- * mark_journal_empty() - Mark on disk journal as empty.
- * @journal: The journal to update.
- *
- * Update a journal's dynamic superblock fields to show that journal is empty.
- * Write updated superblock to disk waiting for IO to complete.
- */
-static void mark_journal_empty(journal_t *journal)
-{
-	journal_superblock_t *sb = journal->j_superblock;
-
-	BUG_ON(!mutex_is_locked(&journal->j_checkpoint_mutex));
-	spin_lock(&journal->j_state_lock);
-	/* Is it already empty? */
-	if (sb->s_start == 0) {
-		spin_unlock(&journal->j_state_lock);
-		return;
-	}
-	jbd_debug(1, "JBD: Marking journal as empty (seq %d)\n",
-        	  journal->j_tail_sequence);
-
-	sb->s_sequence = cpu_to_be32(journal->j_tail_sequence);
-	sb->s_start    = cpu_to_be32(0);
-	spin_unlock(&journal->j_state_lock);
-
-	journal_write_superblock(journal, WRITE_FUA);
-
-	spin_lock(&journal->j_state_lock);
-	/* Log is empty */
-	journal->j_flags |= JFS_FLUSHED;
-	spin_unlock(&journal->j_state_lock);
-}
-
-/**
- * journal_update_sb_errno() - Update error in the journal.
- * @journal: The journal to update.
- *
- * Update a journal's errno.  Write updated superblock to disk waiting for IO
- * to complete.
- */
-static void journal_update_sb_errno(journal_t *journal)
-{
-	journal_superblock_t *sb = journal->j_superblock;
-
-	spin_lock(&journal->j_state_lock);
-	jbd_debug(1, "JBD: updating superblock error (errno %d)\n",
-        	  journal->j_errno);
-	sb->s_errno = cpu_to_be32(journal->j_errno);
-	spin_unlock(&journal->j_state_lock);
-
-	journal_write_superblock(journal, WRITE_SYNC);
-}
-
-/*
- * Read the superblock for a given journal, performing initial
- * validation of the format.
- */
-
-static int journal_get_superblock(journal_t *journal)
-{
-	struct buffer_head *bh;
-	journal_superblock_t *sb;
-	int err = -EIO;
-
-	bh = journal->j_sb_buffer;
-
-	J_ASSERT(bh != NULL);
-	if (!buffer_uptodate(bh)) {
-		ll_rw_block(READ, 1, &bh);
-		wait_on_buffer(bh);
-		if (!buffer_uptodate(bh)) {
-			printk (KERN_ERR
-				"JBD: IO error reading journal superblock\n");
-			goto out;
-		}
-	}
-
-	sb = journal->j_superblock;
-
-	err = -EINVAL;
-
-	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(be32_to_cpu(sb->s_header.h_blocktype)) {
-	case JFS_SUPERBLOCK_V1:
-		journal->j_format_version = 1;
-		break;
-	case JFS_SUPERBLOCK_V2:
-		journal->j_format_version = 2;
-		break;
-	default:
-		printk(KERN_WARNING "JBD: unrecognised superblock format ID\n");
-		goto out;
-	}
-
-	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;
-	}
-
-	if (be32_to_cpu(sb->s_first) == 0 ||
-	    be32_to_cpu(sb->s_first) >= journal->j_maxlen) {
-		printk(KERN_WARNING
-			"JBD: Invalid start block of journal: %u\n",
-			be32_to_cpu(sb->s_first));
-		goto out;
-	}
-
-	return 0;
-
-out:
-	journal_fail_superblock(journal);
-	return err;
-}
-
-/*
- * Load the on-disk journal superblock and read the key fields into the
- * journal_t.
- */
-
-static int load_superblock(journal_t *journal)
-{
-	int err;
-	journal_superblock_t *sb;
-
-	err = journal_get_superblock(journal);
-	if (err)
-		return err;
-
-	sb = journal->j_superblock;
-
-	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;
-}
-
-
-/**
- * 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.
- */
-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) {
-		if ((sb->s_feature_ro_compat &
-		     ~cpu_to_be32(JFS_KNOWN_ROCOMPAT_FEATURES)) ||
-		    (sb->s_feature_incompat &
-		     ~cpu_to_be32(JFS_KNOWN_INCOMPAT_FEATURES))) {
-			printk (KERN_WARNING
-				"JBD: Unrecognised features on journal\n");
-			return -EINVAL;
-		}
-	}
-
-	/* Let the recovery code check whether it needs to recover any
-	 * data from the journal. */
-	if (journal_recover(journal))
-		goto recovery_error;
-
-	/* OK, we've finished with the dynamic journal bits:
-	 * reinitialise the dynamic contents of the superblock in memory
-	 * and reset them on disk. */
-	if (journal_reset(journal))
-		goto recovery_error;
-
-	journal->j_flags &= ~JFS_ABORT;
-	journal->j_flags |= JFS_LOADED;
-	return 0;
-
-recovery_error:
-	printk (KERN_WARNING "JBD: recovery failed\n");
-	return -EIO;
-}
-
-/**
- * void journal_destroy() - Release a journal_t structure.
- * @journal: Journal to act on.
- *
- * Release a journal_t structure once it is no longer in use by the
- * journaled object.
- * Return <0 if we couldn't clean up the journal.
- */
-int journal_destroy(journal_t *journal)
-{
-	int err = 0;
-
-	
-	/* Wait for the commit thread to wake up and die. */
-	journal_kill_thread(journal);
-
-	/* Force a final log commit */
-	if (journal->j_running_transaction)
-		journal_commit_transaction(journal);
-
-	/* Force any old transactions to disk */
-
-	/* We cannot race with anybody but must keep assertions happy */
-	mutex_lock(&journal->j_checkpoint_mutex);
-	/* Totally anal locking here... */
-	spin_lock(&journal->j_list_lock);
-	while (journal->j_checkpoint_transactions != NULL) {
-		spin_unlock(&journal->j_list_lock);
-		log_do_checkpoint(journal);
-		spin_lock(&journal->j_list_lock);
-	}
-
-	J_ASSERT(journal->j_running_transaction == NULL);
-	J_ASSERT(journal->j_committing_transaction == NULL);
-	J_ASSERT(journal->j_checkpoint_transactions == NULL);
-	spin_unlock(&journal->j_list_lock);
-
-	if (journal->j_sb_buffer) {
-		if (!is_journal_aborted(journal)) {
-			journal->j_tail_sequence =
-				++journal->j_transaction_sequence;
-			mark_journal_empty(journal);
-		} else
-			err = -EIO;
-		brelse(journal->j_sb_buffer);
-	}
-	mutex_unlock(&journal->j_checkpoint_mutex);
-
-	iput(journal->j_inode);
-	if (journal->j_revoke)
-		journal_destroy_revoke(journal);
-	kfree(journal->j_wbuf);
-	kfree(journal);
-
-	return err;
-}
-
-
-/**
- *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.
- **/
-
-int journal_check_used_features (journal_t *journal, unsigned long compat,
-				 unsigned long ro, unsigned long incompat)
-{
-	journal_superblock_t *sb;
-
-	if (!compat && !ro && !incompat)
-		return 1;
-	if (journal->j_format_version == 1)
-		return 0;
-
-	sb = journal->j_superblock;
-
-	if (((be32_to_cpu(sb->s_feature_compat) & compat) == compat) &&
-	    ((be32_to_cpu(sb->s_feature_ro_compat) & ro) == ro) &&
-	    ((be32_to_cpu(sb->s_feature_incompat) & incompat) == incompat))
-		return 1;
-
-	return 0;
-}
-
-/**
- * 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. */
-
-int journal_check_available_features (journal_t *journal, unsigned long compat,
-				      unsigned long ro, unsigned long incompat)
-{
-	if (!compat && !ro && !incompat)
-		return 1;
-
-	/* We can support any known requested features iff the
-	 * superblock is in version 2.  Otherwise we fail to support any
-	 * extended sb features. */
-
-	if (journal->j_format_version != 2)
-		return 0;
-
-	if ((compat   & JFS_KNOWN_COMPAT_FEATURES) == compat &&
-	    (ro       & JFS_KNOWN_ROCOMPAT_FEATURES) == ro &&
-	    (incompat & JFS_KNOWN_INCOMPAT_FEATURES) == incompat)
-		return 1;
-
-	return 0;
-}
-
-/**
- * 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.
- *
- */
-
-int journal_set_features (journal_t *journal, unsigned long compat,
-			  unsigned long ro, unsigned long incompat)
-{
-	journal_superblock_t *sb;
-
-	if (journal_check_used_features(journal, compat, ro, incompat))
-		return 1;
-
-	if (!journal_check_available_features(journal, compat, ro, incompat))
-		return 0;
-
-	jbd_debug(1, "Setting new features 0x%lx/0x%lx/0x%lx\n",
-		  compat, ro, incompat);
-
-	sb = journal->j_superblock;
-
-	sb->s_feature_compat    |= cpu_to_be32(compat);
-	sb->s_feature_ro_compat |= cpu_to_be32(ro);
-	sb->s_feature_incompat  |= cpu_to_be32(incompat);
-
-	return 1;
-}
-
-
-/**
- * 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.
- */
-int journal_update_format (journal_t *journal)
-{
-	journal_superblock_t *sb;
-	int err;
-
-	err = journal_get_superblock(journal);
-	if (err)
-		return err;
-
-	sb = journal->j_superblock;
-
-	switch (be32_to_cpu(sb->s_header.h_blocktype)) {
-	case JFS_SUPERBLOCK_V2:
-		return 0;
-	case JFS_SUPERBLOCK_V1:
-		return journal_convert_superblock_v1(journal, sb);
-	default:
-		break;
-	}
-	return -EINVAL;
-}
-
-static int journal_convert_superblock_v1(journal_t *journal,
-					 journal_superblock_t *sb)
-{
-	int offset, blocksize;
-	struct buffer_head *bh;
-
-	printk(KERN_WARNING
-		"JBD: Converting superblock from version 1 to 2.\n");
-
-	/* Pre-initialise new fields to zero */
-	offset = ((char *) &(sb->s_feature_compat)) - ((char *) sb);
-	blocksize = be32_to_cpu(sb->s_blocksize);
-	memset(&sb->s_feature_compat, 0, blocksize-offset);
-
-	sb->s_nr_users = cpu_to_be32(1);
-	sb->s_header.h_blocktype = cpu_to_be32(JFS_SUPERBLOCK_V2);
-	journal->j_format_version = 2;
-
-	bh = journal->j_sb_buffer;
-	BUFFER_TRACE(bh, "marking dirty");
-	mark_buffer_dirty(bh);
-	sync_dirty_buffer(bh);
-	return 0;
-}
-
-
-/**
- * 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.
- */
-
-int journal_flush(journal_t *journal)
-{
-	int err = 0;
-	transaction_t *transaction = NULL;
-
-	spin_lock(&journal->j_state_lock);
-
-	/* Force everything buffered to the log... */
-	if (journal->j_running_transaction) {
-		transaction = journal->j_running_transaction;
-		__log_start_commit(journal, transaction->t_tid);
-	} else if (journal->j_committing_transaction)
-		transaction = journal->j_committing_transaction;
-
-	/* Wait for the log commit to complete... */
-	if (transaction) {
-		tid_t tid = transaction->t_tid;
-
-		spin_unlock(&journal->j_state_lock);
-		log_wait_commit(journal, tid);
-	} else {
-		spin_unlock(&journal->j_state_lock);
-	}
-
-	/* ...and flush everything in the log out to disk. */
-	spin_lock(&journal->j_list_lock);
-	while (!err && journal->j_checkpoint_transactions != NULL) {
-		spin_unlock(&journal->j_list_lock);
-		mutex_lock(&journal->j_checkpoint_mutex);
-		err = log_do_checkpoint(journal);
-		mutex_unlock(&journal->j_checkpoint_mutex);
-		spin_lock(&journal->j_list_lock);
-	}
-	spin_unlock(&journal->j_list_lock);
-
-	if (is_journal_aborted(journal))
-		return -EIO;
-
-	mutex_lock(&journal->j_checkpoint_mutex);
-	cleanup_journal_tail(journal);
-
-	/* Finally, mark the journal as really needing no recovery.
-	 * This sets s_start==0 in the underlying superblock, which is
-	 * the magic code for a fully-recovered superblock.  Any future
-	 * commits of data to the journal will restore the current
-	 * s_start value. */
-	mark_journal_empty(journal);
-	mutex_unlock(&journal->j_checkpoint_mutex);
-	spin_lock(&journal->j_state_lock);
-	J_ASSERT(!journal->j_running_transaction);
-	J_ASSERT(!journal->j_committing_transaction);
-	J_ASSERT(!journal->j_checkpoint_transactions);
-	J_ASSERT(journal->j_head == journal->j_tail);
-	J_ASSERT(journal->j_tail_sequence == journal->j_transaction_sequence);
-	spin_unlock(&journal->j_state_lock);
-	return 0;
-}
-
-/**
- * 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().
- *
- * If 'write' is non-zero, then we wipe out the journal on disk; otherwise
- * we merely suppress recovery.
- */
-
-int journal_wipe(journal_t *journal, int write)
-{
-	int err = 0;
-
-	J_ASSERT (!(journal->j_flags & JFS_LOADED));
-
-	err = load_superblock(journal);
-	if (err)
-		return err;
-
-	if (!journal->j_tail)
-		goto no_recovery;
-
-	printk (KERN_WARNING "JBD: %s recovery information on journal\n",
-		write ? "Clearing" : "Ignoring");
-
-	err = journal_skip_recovery(journal);
-	if (write) {
-		/* Lock to make assertions happy... */
-		mutex_lock(&journal->j_checkpoint_mutex);
-		mark_journal_empty(journal);
-		mutex_unlock(&journal->j_checkpoint_mutex);
-	}
-
- no_recovery:
-	return err;
-}
-
-/*
- * journal_dev_name: format a character string to describe on what
- * device this journal is present.
- */
-
-static const char *journal_dev_name(journal_t *journal, char *buffer)
-{
-	struct block_device *bdev;
-
-	if (journal->j_inode)
-		bdev = journal->j_inode->i_sb->s_bdev;
-	else
-		bdev = journal->j_dev;
-
-	return bdevname(bdev, buffer);
-}
-
-/*
- * Journal abort has very specific semantics, which we describe
- * for journal abort.
- *
- * Two internal function, which provide abort to te jbd layer
- * itself are here.
- */
-
-/*
- * Quick version for internal journal use (doesn't lock the journal).
- * Aborts hard --- we mark the abort as occurred, but do _nothing_ else,
- * and don't attempt to make any other journal updates.
- */
-static void __journal_abort_hard(journal_t *journal)
-{
-	transaction_t *transaction;
-	char b[BDEVNAME_SIZE];
-
-	if (journal->j_flags & JFS_ABORT)
-		return;
-
-	printk(KERN_ERR "Aborting journal on device %s.\n",
-		journal_dev_name(journal, b));
-
-	spin_lock(&journal->j_state_lock);
-	journal->j_flags |= JFS_ABORT;
-	transaction = journal->j_running_transaction;
-	if (transaction)
-		__log_start_commit(journal, transaction->t_tid);
-	spin_unlock(&journal->j_state_lock);
-}
-
-/* Soft abort: record the abort error status in the journal superblock,
- * but don't do any other IO. */
-static void __journal_abort_soft (journal_t *journal, int errno)
-{
-	if (journal->j_flags & JFS_ABORT)
-		return;
-
-	if (!journal->j_errno)
-		journal->j_errno = errno;
-
-	__journal_abort_hard(journal);
-
-	if (errno)
-		journal_update_sb_errno(journal);
-}
-
-/**
- * void journal_abort () - Shutdown the journal immediately.
- * @journal: the journal to shutdown.
- * @errno:   an error number to record in the journal indicating
- *           the reason for the shutdown.
- *
- * 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.
- *
- * Journal abort has very specific semantics.  Any existing dirty,
- * unjournaled buffers in the main filesystem will still be written to
- * disk by bdflush, but the journaling mechanism will be suspended
- * immediately and no further transaction commits will be honoured.
- *
- * Any dirty, journaled buffers will be written back to disk without
- * hitting the journal.  Atomicity cannot be guaranteed on an aborted
- * filesystem, but we _do_ attempt to leave as much data as possible
- * behind for fsck to use for cleanup.
- *
- * Any attempt to get a new transaction handle on a journal which is in
- * ABORT state will just result in an -EROFS error return.  A
- * journal_stop on an existing handle will return -EIO if we have
- * entered abort state during the update.
- *
- * Recursive transactions are not disturbed by journal abort until the
- * final journal_stop, which will receive the -EIO error.
- *
- * Finally, the journal_abort call allows the caller to supply an errno
- * which will be recorded (if possible) in the journal superblock.  This
- * allows a client to record failure conditions in the middle of a
- * transaction without having to complete the transaction to record the
- * failure to disk.  ext3_error, for example, now uses this
- * functionality.
- *
- * Errors which originate from within the journaling layer will NOT
- * 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)
-{
-	__journal_abort_soft(journal, errno);
-}
-
-/**
- * int journal_errno () - returns the journal's error state.
- * @journal: journal to examine.
- *
- * This is the errno numbet set with journal_abort(), the last
- * time the journal was mounted - if the journal was stopped
- * without calling abort this will be 0.
- *
- * If the journal has been aborted on this mount time -EROFS will
- * be returned.
- */
-int journal_errno(journal_t *journal)
-{
-	int err;
-
-	spin_lock(&journal->j_state_lock);
-	if (journal->j_flags & JFS_ABORT)
-		err = -EROFS;
-	else
-		err = journal->j_errno;
-	spin_unlock(&journal->j_state_lock);
-	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.
- */
-int journal_clear_err(journal_t *journal)
-{
-	int err = 0;
-
-	spin_lock(&journal->j_state_lock);
-	if (journal->j_flags & JFS_ABORT)
-		err = -EROFS;
-	else
-		journal->j_errno = 0;
-	spin_unlock(&journal->j_state_lock);
-	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.
- */
-void journal_ack_err(journal_t *journal)
-{
-	spin_lock(&journal->j_state_lock);
-	if (journal->j_errno)
-		journal->j_flags |= JFS_ACK_ERR;
-	spin_unlock(&journal->j_state_lock);
-}
-
-int journal_blocks_per_page(struct inode *inode)
-{
-	return 1 << (PAGE_CACHE_SHIFT - inode->i_sb->s_blocksize_bits);
-}
-
-/*
- * Journal_head storage management
- */
-static struct kmem_cache *journal_head_cache;
-#ifdef CONFIG_JBD_DEBUG
-static atomic_t nr_journal_heads = ATOMIC_INIT(0);
-#endif
-
-static int journal_init_journal_head_cache(void)
-{
-	int retval;
-
-	J_ASSERT(journal_head_cache == NULL);
-	journal_head_cache = kmem_cache_create("journal_head",
-				sizeof(struct journal_head),
-				0,		/* offset */
-				SLAB_TEMPORARY,	/* flags */
-				NULL);		/* ctor */
-	retval = 0;
-	if (!journal_head_cache) {
-		retval = -ENOMEM;
-		printk(KERN_EMERG "JBD: no memory for journal_head cache\n");
-	}
-	return retval;
-}
-
-static void journal_destroy_journal_head_cache(void)
-{
-	if (journal_head_cache) {
-		kmem_cache_destroy(journal_head_cache);
-		journal_head_cache = NULL;
-	}
-}
-
-/*
- * journal_head splicing and dicing
- */
-static struct journal_head *journal_alloc_journal_head(void)
-{
-	struct journal_head *ret;
-
-#ifdef CONFIG_JBD_DEBUG
-	atomic_inc(&nr_journal_heads);
-#endif
-	ret = kmem_cache_zalloc(journal_head_cache, GFP_NOFS);
-	if (ret == NULL) {
-		jbd_debug(1, "out of memory for journal_head\n");
-		printk_ratelimited(KERN_NOTICE "ENOMEM in %s, retrying.\n",
-				   __func__);
-
-		while (ret == NULL) {
-			yield();
-			ret = kmem_cache_zalloc(journal_head_cache, GFP_NOFS);
-		}
-	}
-	return ret;
-}
-
-static void journal_free_journal_head(struct journal_head *jh)
-{
-#ifdef CONFIG_JBD_DEBUG
-	atomic_dec(&nr_journal_heads);
-	memset(jh, JBD_POISON_FREE, sizeof(*jh));
-#endif
-	kmem_cache_free(journal_head_cache, jh);
-}
-
-/*
- * A journal_head is attached to a buffer_head whenever JBD has an
- * interest in the buffer.
- *
- * Whenever a buffer has an attached journal_head, its ->b_state:BH_JBD bit
- * is set.  This bit is tested in core kernel code where we need to take
- * JBD-specific actions.  Testing the zeroness of ->b_private is not reliable
- * there.
- *
- * When a buffer has its BH_JBD bit set, its ->b_count is elevated by one.
- *
- * When a buffer has its BH_JBD bit set it is immune from being released by
- * core kernel code, mainly via ->b_count.
- *
- * A journal_head is detached from its buffer_head when the journal_head's
- * b_jcount reaches zero. Running transaction (b_transaction) and checkpoint
- * transaction (b_cp_transaction) hold their references to b_jcount.
- *
- * Various places in the kernel want to attach a journal_head to a buffer_head
- * _before_ attaching the journal_head to a transaction.  To protect the
- * journal_head in this situation, journal_add_journal_head elevates the
- * journal_head's b_jcount refcount by one.  The caller must call
- * journal_put_journal_head() to undo this.
- *
- * So the typical usage would be:
- *
- *	(Attach a journal_head if needed.  Increments b_jcount)
- *	struct journal_head *jh = journal_add_journal_head(bh);
- *	...
- *      (Get another reference for transaction)
- *      journal_grab_journal_head(bh);
- *      jh->b_transaction = xxx;
- *      (Put original reference)
- *      journal_put_journal_head(jh);
- */
-
-/*
- * Give a buffer_head a journal_head.
- *
- * May sleep.
- */
-struct journal_head *journal_add_journal_head(struct buffer_head *bh)
-{
-	struct journal_head *jh;
-	struct journal_head *new_jh = NULL;
-
-repeat:
-	if (!buffer_jbd(bh))
-		new_jh = journal_alloc_journal_head();
-
-	jbd_lock_bh_journal_head(bh);
-	if (buffer_jbd(bh)) {
-		jh = bh2jh(bh);
-	} else {
-		J_ASSERT_BH(bh,
-			(atomic_read(&bh->b_count) > 0) ||
-			(bh->b_page && bh->b_page->mapping));
-
-		if (!new_jh) {
-			jbd_unlock_bh_journal_head(bh);
-			goto repeat;
-		}
-
-		jh = new_jh;
-		new_jh = NULL;		/* We consumed it */
-		set_buffer_jbd(bh);
-		bh->b_private = jh;
-		jh->b_bh = bh;
-		get_bh(bh);
-		BUFFER_TRACE(bh, "added journal_head");
-	}
-	jh->b_jcount++;
-	jbd_unlock_bh_journal_head(bh);
-	if (new_jh)
-		journal_free_journal_head(new_jh);
-	return bh->b_private;
-}
-
-/*
- * Grab a ref against this buffer_head's journal_head.  If it ended up not
- * having a journal_head, return NULL
- */
-struct journal_head *journal_grab_journal_head(struct buffer_head *bh)
-{
-	struct journal_head *jh = NULL;
-
-	jbd_lock_bh_journal_head(bh);
-	if (buffer_jbd(bh)) {
-		jh = bh2jh(bh);
-		jh->b_jcount++;
-	}
-	jbd_unlock_bh_journal_head(bh);
-	return jh;
-}
-
-static void __journal_remove_journal_head(struct buffer_head *bh)
-{
-	struct journal_head *jh = bh2jh(bh);
-
-	J_ASSERT_JH(jh, jh->b_jcount >= 0);
-	J_ASSERT_JH(jh, jh->b_transaction == NULL);
-	J_ASSERT_JH(jh, jh->b_next_transaction == NULL);
-	J_ASSERT_JH(jh, 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");
-	if (jh->b_frozen_data) {
-		printk(KERN_WARNING "%s: freeing b_frozen_data\n", __func__);
-		jbd_free(jh->b_frozen_data, bh->b_size);
-	}
-	if (jh->b_committed_data) {
-		printk(KERN_WARNING "%s: freeing b_committed_data\n", __func__);
-		jbd_free(jh->b_committed_data, bh->b_size);
-	}
-	bh->b_private = NULL;
-	jh->b_bh = NULL;	/* debug, really */
-	clear_buffer_jbd(bh);
-	journal_free_journal_head(jh);
-}
-
-/*
- * Drop a reference on the passed journal_head.  If it fell to zero then
- * release the journal_head from the buffer_head.
- */
-void journal_put_journal_head(struct journal_head *jh)
-{
-	struct buffer_head *bh = jh2bh(jh);
-
-	jbd_lock_bh_journal_head(bh);
-	J_ASSERT_JH(jh, jh->b_jcount > 0);
-	--jh->b_jcount;
-	if (!jh->b_jcount) {
-		__journal_remove_journal_head(bh);
-		jbd_unlock_bh_journal_head(bh);
-		__brelse(bh);
-	} else
-		jbd_unlock_bh_journal_head(bh);
-}
-
-/*
- * debugfs tunables
- */
-#ifdef CONFIG_JBD_DEBUG
-
-u8 journal_enable_debug __read_mostly;
-EXPORT_SYMBOL(journal_enable_debug);
-
-static struct dentry *jbd_debugfs_dir;
-static struct dentry *jbd_debug;
-
-static void __init jbd_create_debugfs_entry(void)
-{
-	jbd_debugfs_dir = debugfs_create_dir("jbd", NULL);
-	if (jbd_debugfs_dir)
-		jbd_debug = debugfs_create_u8("jbd-debug", S_IRUGO | S_IWUSR,
-					       jbd_debugfs_dir,
-					       &journal_enable_debug);
-}
-
-static void __exit jbd_remove_debugfs_entry(void)
-{
-	debugfs_remove(jbd_debug);
-	debugfs_remove(jbd_debugfs_dir);
-}
-
-#else
-
-static inline void jbd_create_debugfs_entry(void)
-{
-}
-
-static inline void jbd_remove_debugfs_entry(void)
-{
-}
-
-#endif
-
-struct kmem_cache *jbd_handle_cache;
-
-static int __init journal_init_handle_cache(void)
-{
-	jbd_handle_cache = kmem_cache_create("journal_handle",
-				sizeof(handle_t),
-				0,		/* offset */
-				SLAB_TEMPORARY,	/* flags */
-				NULL);		/* ctor */
-	if (jbd_handle_cache == NULL) {
-		printk(KERN_EMERG "JBD: failed to create handle cache\n");
-		return -ENOMEM;
-	}
-	return 0;
-}
-
-static void journal_destroy_handle_cache(void)
-{
-	if (jbd_handle_cache)
-		kmem_cache_destroy(jbd_handle_cache);
-}
-
-/*
- * Module startup and shutdown
- */
-
-static int __init journal_init_caches(void)
-{
-	int ret;
-
-	ret = journal_init_revoke_caches();
-	if (ret == 0)
-		ret = journal_init_journal_head_cache();
-	if (ret == 0)
-		ret = journal_init_handle_cache();
-	return ret;
-}
-
-static void journal_destroy_caches(void)
-{
-	journal_destroy_revoke_caches();
-	journal_destroy_journal_head_cache();
-	journal_destroy_handle_cache();
-}
-
-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();
-	jbd_create_debugfs_entry();
-	return ret;
-}
-
-static void __exit journal_exit(void)
-{
-#ifdef CONFIG_JBD_DEBUG
-	int n = atomic_read(&nr_journal_heads);
-	if (n)
-		printk(KERN_ERR "JBD: leaked %d journal_heads!\n", n);
-#endif
-	jbd_remove_debugfs_entry();
-	journal_destroy_caches();
-}
-
-MODULE_LICENSE("GPL");
-module_init(journal_init);
-module_exit(journal_exit);
-