Merge tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4

Pull ext4 update from Ted Ts'o:
 "Lots of bug fixes, cleanups and optimizations.  In the bug fixes
  category, of note is a fix for on-line resizing file systems where the
  block size is smaller than the page size (i.e., file systems 1k blocks
  on x86, or more interestingly file systems with 4k blocks on Power or
  ia64 systems.)

  In the cleanup category, the ext4's punch hole implementation was
  significantly improved by Lukas Czerner, and now supports bigalloc
  file systems.  In addition, Jan Kara significantly cleaned up the
  write submission code path.  We also improved error checking and added
  a few sanity checks.

  In the optimizations category, two major optimizations deserve
  mention.  The first is that ext4_writepages() is now used for
  nodelalloc and ext3 compatibility mode.  This allows writes to be
  submitted much more efficiently as a single bio request, instead of
  being sent as individual 4k writes into the block layer (which then
  relied on the elevator code to coalesce the requests in the block
  queue).  Secondly, the extent cache shrink mechanism, which was
  introduce in 3.9, no longer has a scalability bottleneck caused by the
  i_es_lru spinlock.  Other optimizations include some changes to reduce
  CPU usage and to avoid issuing empty commits unnecessarily."

* tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (86 commits)
  ext4: optimize starting extent in ext4_ext_rm_leaf()
  jbd2: invalidate handle if jbd2_journal_restart() fails
  ext4: translate flag bits to strings in tracepoints
  ext4: fix up error handling for mpage_map_and_submit_extent()
  jbd2: fix theoretical race in jbd2__journal_restart
  ext4: only zero partial blocks in ext4_zero_partial_blocks()
  ext4: check error return from ext4_write_inline_data_end()
  ext4: delete unnecessary C statements
  ext3,ext4: don't mess with dir_file->f_pos in htree_dirblock_to_tree()
  jbd2: move superblock checksum calculation to jbd2_write_superblock()
  ext4: pass inode pointer instead of file pointer to punch hole
  ext4: improve free space calculation for inline_data
  ext4: reduce object size when !CONFIG_PRINTK
  ext4: improve extent cache shrink mechanism to avoid to burn CPU time
  ext4: implement error handling of ext4_mb_new_preallocation()
  ext4: fix corruption when online resizing a fs with 1K block size
  ext4: delete unused variables
  ext4: return FIEMAP_EXTENT_UNKNOWN for delalloc extents
  jbd2: remove debug dependency on debug_fs and update Kconfig help text
  jbd2: use a single printk for jbd_debug()
  ...

1 files changed, 326 insertions, 200 deletions

diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c
index 10f524c..7aa9a32 100644
--- a/fs/jbd2/transaction.c
+++ b/fs/jbd2/transaction.c
@@ -89,7 +89,8 @@ jbd2_get_transaction(journal_t *journal, transaction_t *transaction)
 	transaction->t_expires = jiffies + journal->j_commit_interval;
 	spin_lock_init(&transaction->t_handle_lock);
 	atomic_set(&transaction->t_updates, 0);
-	atomic_set(&transaction->t_outstanding_credits, 0);
+	atomic_set(&transaction->t_outstanding_credits,
+		   atomic_read(&journal->j_reserved_credits));
 	atomic_set(&transaction->t_handle_count, 0);
 	INIT_LIST_HEAD(&transaction->t_inode_list);
 	INIT_LIST_HEAD(&transaction->t_private_list);
@@ -141,6 +142,112 @@ static inline void update_t_max_wait(transaction_t *transaction,
 }
 
 /*
+ * Wait until running transaction passes T_LOCKED state. Also starts the commit
+ * if needed. The function expects running transaction to exist and releases
+ * j_state_lock.
+ */
+static void wait_transaction_locked(journal_t *journal)
+	__releases(journal->j_state_lock)
+{
+	DEFINE_WAIT(wait);
+	int need_to_start;
+	tid_t tid = journal->j_running_transaction->t_tid;
+
+	prepare_to_wait(&journal->j_wait_transaction_locked, &wait,
+			TASK_UNINTERRUPTIBLE);
+	need_to_start = !tid_geq(journal->j_commit_request, tid);
+	read_unlock(&journal->j_state_lock);
+	if (need_to_start)
+		jbd2_log_start_commit(journal, tid);
+	schedule();
+	finish_wait(&journal->j_wait_transaction_locked, &wait);
+}
+
+static void sub_reserved_credits(journal_t *journal, int blocks)
+{
+	atomic_sub(blocks, &journal->j_reserved_credits);
+	wake_up(&journal->j_wait_reserved);
+}
+
+/*
+ * Wait until we can add credits for handle to the running transaction.  Called
+ * with j_state_lock held for reading. Returns 0 if handle joined the running
+ * transaction. Returns 1 if we had to wait, j_state_lock is dropped, and
+ * caller must retry.
+ */
+static int add_transaction_credits(journal_t *journal, int blocks,
+				   int rsv_blocks)
+{
+	transaction_t *t = journal->j_running_transaction;
+	int needed;
+	int total = blocks + rsv_blocks;
+
+	/*
+	 * If the current transaction is locked down for commit, wait
+	 * for the lock to be released.
+	 */
+	if (t->t_state == T_LOCKED) {
+		wait_transaction_locked(journal);
+		return 1;
+	}
+
+	/*
+	 * If there is not enough space left in the log to write all
+	 * potential buffers requested by this operation, we need to
+	 * stall pending a log checkpoint to free some more log space.
+	 */
+	needed = atomic_add_return(total, &t->t_outstanding_credits);
+	if (needed > journal->j_max_transaction_buffers) {
+		/*
+		 * If the current transaction is already too large,
+		 * then start to commit it: we can then go back and
+		 * attach this handle to a new transaction.
+		 */
+		atomic_sub(total, &t->t_outstanding_credits);
+		wait_transaction_locked(journal);
+		return 1;
+	}
+
+	/*
+	 * The commit code assumes that it can get enough log space
+	 * without forcing a checkpoint.  This is *critical* for
+	 * correctness: a checkpoint of a buffer which is also
+	 * associated with a committing transaction creates a deadlock,
+	 * so commit simply cannot force through checkpoints.
+	 *
+	 * We must therefore ensure the necessary space in the journal
+	 * *before* starting to dirty potentially checkpointed buffers
+	 * in the new transaction.
+	 */
+	if (jbd2_log_space_left(journal) < jbd2_space_needed(journal)) {
+		atomic_sub(total, &t->t_outstanding_credits);
+		read_unlock(&journal->j_state_lock);
+		write_lock(&journal->j_state_lock);
+		if (jbd2_log_space_left(journal) < jbd2_space_needed(journal))
+			__jbd2_log_wait_for_space(journal);
+		write_unlock(&journal->j_state_lock);
+		return 1;
+	}
+
+	/* No reservation? We are done... */
+	if (!rsv_blocks)
+		return 0;
+
+	needed = atomic_add_return(rsv_blocks, &journal->j_reserved_credits);
+	/* We allow at most half of a transaction to be reserved */
+	if (needed > journal->j_max_transaction_buffers / 2) {
+		sub_reserved_credits(journal, rsv_blocks);
+		atomic_sub(total, &t->t_outstanding_credits);
+		read_unlock(&journal->j_state_lock);
+		wait_event(journal->j_wait_reserved,
+			 atomic_read(&journal->j_reserved_credits) + rsv_blocks
+			 <= journal->j_max_transaction_buffers / 2);
+		return 1;
+	}
+	return 0;
+}
+
+/*
  * start_this_handle: Given a handle, deal with any locking or stalling
  * needed to make sure that there is enough journal space for the handle
  * to begin.  Attach the handle to a transaction and set up the
@@ -151,18 +258,24 @@ static int start_this_handle(journal_t *journal, handle_t *handle,
 			     gfp_t gfp_mask)
 {
 	transaction_t	*transaction, *new_transaction = NULL;
-	tid_t		tid;
-	int		needed, need_to_start;
-	int		nblocks = handle->h_buffer_credits;
+	int		blocks = handle->h_buffer_credits;
+	int		rsv_blocks = 0;
 	unsigned long ts = jiffies;
 
-	if (nblocks > journal->j_max_transaction_buffers) {
+	/*
+	 * 1/2 of transaction can be reserved so we can practically handle
+	 * only 1/2 of maximum transaction size per operation
+	 */
+	if (WARN_ON(blocks > journal->j_max_transaction_buffers / 2)) {
 		printk(KERN_ERR "JBD2: %s wants too many credits (%d > %d)\n",
-		       current->comm, nblocks,
-		       journal->j_max_transaction_buffers);
+		       current->comm, blocks,
+		       journal->j_max_transaction_buffers / 2);
 		return -ENOSPC;
 	}
 
+	if (handle->h_rsv_handle)
+		rsv_blocks = handle->h_rsv_handle->h_buffer_credits;
+
 alloc_transaction:
 	if (!journal->j_running_transaction) {
 		new_transaction = kmem_cache_zalloc(transaction_cache,
@@ -199,8 +312,12 @@ repeat:
 		return -EROFS;
 	}
 
-	/* Wait on the journal's transaction barrier if necessary */
-	if (journal->j_barrier_count) {
+	/*
+	 * Wait on the journal's transaction barrier if necessary. Specifically
+	 * we allow reserved handles to proceed because otherwise commit could
+	 * deadlock on page writeback not being able to complete.
+	 */
+	if (!handle->h_reserved && journal->j_barrier_count) {
 		read_unlock(&journal->j_state_lock);
 		wait_event(journal->j_wait_transaction_locked,
 				journal->j_barrier_count == 0);
@@ -213,7 +330,7 @@ repeat:
 			goto alloc_transaction;
 		write_lock(&journal->j_state_lock);
 		if (!journal->j_running_transaction &&
-		    !journal->j_barrier_count) {
+		    (handle->h_reserved || !journal->j_barrier_count)) {
 			jbd2_get_transaction(journal, new_transaction);
 			new_transaction = NULL;
 		}
@@ -223,85 +340,18 @@ repeat:
 
 	transaction = journal->j_running_transaction;
 
-	/*
-	 * If the current transaction is locked down for commit, wait for the
-	 * lock to be released.
-	 */
-	if (transaction->t_state == T_LOCKED) {
-		DEFINE_WAIT(wait);
-
-		prepare_to_wait(&journal->j_wait_transaction_locked,
-					&wait, TASK_UNINTERRUPTIBLE);
-		read_unlock(&journal->j_state_lock);
-		schedule();
-		finish_wait(&journal->j_wait_transaction_locked, &wait);
-		goto repeat;
-	}
-
-	/*
-	 * If there is not enough space left in the log to write all potential
-	 * buffers requested by this operation, we need to stall pending a log
-	 * checkpoint to free some more log space.
-	 */
-	needed = atomic_add_return(nblocks,
-				   &transaction->t_outstanding_credits);
-
-	if (needed > journal->j_max_transaction_buffers) {
+	if (!handle->h_reserved) {
+		/* We may have dropped j_state_lock - restart in that case */
+		if (add_transaction_credits(journal, blocks, rsv_blocks))
+			goto repeat;
+	} else {
 		/*
-		 * If the current transaction is already too large, then start
-		 * to commit it: we can then go back and attach this handle to
-		 * a new transaction.
+		 * We have handle reserved so we are allowed to join T_LOCKED
+		 * transaction and we don't have to check for transaction size
+		 * and journal space.
 		 */
-		DEFINE_WAIT(wait);
-
-		jbd_debug(2, "Handle %p starting new commit...\n", handle);
-		atomic_sub(nblocks, &transaction->t_outstanding_credits);
-		prepare_to_wait(&journal->j_wait_transaction_locked, &wait,
-				TASK_UNINTERRUPTIBLE);
-		tid = transaction->t_tid;
-		need_to_start = !tid_geq(journal->j_commit_request, tid);
-		read_unlock(&journal->j_state_lock);
-		if (need_to_start)
-			jbd2_log_start_commit(journal, tid);
-		schedule();
-		finish_wait(&journal->j_wait_transaction_locked, &wait);
-		goto repeat;
-	}
-
-	/*
-	 * The commit code assumes that it can get enough log space
-	 * without forcing a checkpoint.  This is *critical* for
-	 * correctness: a checkpoint of a buffer which is also
-	 * associated with a committing transaction creates a deadlock,
-	 * so commit simply cannot force through checkpoints.
-	 *
-	 * We must therefore ensure the necessary space in the journal
-	 * *before* starting to dirty potentially checkpointed buffers
-	 * in the new transaction.
-	 *
-	 * The worst part is, any transaction currently committing can
-	 * reduce the free space arbitrarily.  Be careful to account for
-	 * those buffers when checkpointing.
-	 */
-
-	/*
-	 * @@@ AKPM: This seems rather over-defensive.  We're giving commit
-	 * a _lot_ of headroom: 1/4 of the journal plus the size of
-	 * the committing transaction.  Really, we only need to give it
-	 * committing_transaction->t_outstanding_credits plus "enough" for
-	 * the log control blocks.
-	 * Also, this test is inconsistent with the matching one in
-	 * jbd2_journal_extend().
-	 */
-	if (__jbd2_log_space_left(journal) < jbd_space_needed(journal)) {
-		jbd_debug(2, "Handle %p waiting for checkpoint...\n", handle);
-		atomic_sub(nblocks, &transaction->t_outstanding_credits);
-		read_unlock(&journal->j_state_lock);
-		write_lock(&journal->j_state_lock);
-		if (__jbd2_log_space_left(journal) < jbd_space_needed(journal))
-			__jbd2_log_wait_for_space(journal);
-		write_unlock(&journal->j_state_lock);
-		goto repeat;
+		sub_reserved_credits(journal, blocks);
+		handle->h_reserved = 0;
 	}
 
 	/* OK, account for the buffers that this operation expects to
@@ -309,15 +359,16 @@ repeat:
 	 */
 	update_t_max_wait(transaction, ts);
 	handle->h_transaction = transaction;
-	handle->h_requested_credits = nblocks;
+	handle->h_requested_credits = blocks;
 	handle->h_start_jiffies = jiffies;
 	atomic_inc(&transaction->t_updates);
 	atomic_inc(&transaction->t_handle_count);
-	jbd_debug(4, "Handle %p given %d credits (total %d, free %d)\n",
-		  handle, nblocks,
+	jbd_debug(4, "Handle %p given %d credits (total %d, free %lu)\n",
+		  handle, blocks,
 		  atomic_read(&transaction->t_outstanding_credits),
-		  __jbd2_log_space_left(journal));
+		  jbd2_log_space_left(journal));
 	read_unlock(&journal->j_state_lock);
+	current->journal_info = handle;
 
 	lock_map_acquire(&handle->h_lockdep_map);
 	jbd2_journal_free_transaction(new_transaction);
@@ -348,16 +399,21 @@ static handle_t *new_handle(int nblocks)
  *
  * We make sure that the transaction can guarantee at least nblocks of
  * modified buffers in the log.  We block until the log can guarantee
- * that much space.
- *
- * This function is visible to journal users (like ext3fs), so is not
- * called with the journal already locked.
+ * that much space. Additionally, if rsv_blocks > 0, we also create another
+ * handle with rsv_blocks reserved blocks in the journal. This handle is
+ * is stored in h_rsv_handle. It is not attached to any particular transaction
+ * and thus doesn't block transaction commit. If the caller uses this reserved
+ * handle, it has to set h_rsv_handle to NULL as otherwise jbd2_journal_stop()
+ * on the parent handle will dispose the reserved one. Reserved handle has to
+ * be converted to a normal handle using jbd2_journal_start_reserved() before
+ * it can be used.
  *
  * Return a pointer to a newly allocated handle, or an ERR_PTR() value
  * on failure.
  */
-handle_t *jbd2__journal_start(journal_t *journal, int nblocks, gfp_t gfp_mask,
-			      unsigned int type, unsigned int line_no)
+handle_t *jbd2__journal_start(journal_t *journal, int nblocks, int rsv_blocks,
+			      gfp_t gfp_mask, unsigned int type,
+			      unsigned int line_no)
 {
 	handle_t *handle = journal_current_handle();
 	int err;
@@ -374,13 +430,24 @@ handle_t *jbd2__journal_start(journal_t *journal, int nblocks, gfp_t gfp_mask,
 	handle = new_handle(nblocks);
 	if (!handle)
 		return ERR_PTR(-ENOMEM);
+	if (rsv_blocks) {
+		handle_t *rsv_handle;
 
-	current->journal_info = handle;
+		rsv_handle = new_handle(rsv_blocks);
+		if (!rsv_handle) {
+			jbd2_free_handle(handle);
+			return ERR_PTR(-ENOMEM);
+		}
+		rsv_handle->h_reserved = 1;
+		rsv_handle->h_journal = journal;
+		handle->h_rsv_handle = rsv_handle;
+	}
 
 	err = start_this_handle(journal, handle, gfp_mask);
 	if (err < 0) {
+		if (handle->h_rsv_handle)
+			jbd2_free_handle(handle->h_rsv_handle);
 		jbd2_free_handle(handle);
-		current->journal_info = NULL;
 		return ERR_PTR(err);
 	}
 	handle->h_type = type;
@@ -395,10 +462,65 @@ EXPORT_SYMBOL(jbd2__journal_start);
 
 handle_t *jbd2_journal_start(journal_t *journal, int nblocks)
 {
-	return jbd2__journal_start(journal, nblocks, GFP_NOFS, 0, 0);
+	return jbd2__journal_start(journal, nblocks, 0, GFP_NOFS, 0, 0);
 }
 EXPORT_SYMBOL(jbd2_journal_start);
 
+void jbd2_journal_free_reserved(handle_t *handle)
+{
+	journal_t *journal = handle->h_journal;
+
+	WARN_ON(!handle->h_reserved);
+	sub_reserved_credits(journal, handle->h_buffer_credits);
+	jbd2_free_handle(handle);
+}
+EXPORT_SYMBOL(jbd2_journal_free_reserved);
+
+/**
+ * int jbd2_journal_start_reserved(handle_t *handle) - start reserved handle
+ * @handle: handle to start
+ *
+ * Start handle that has been previously reserved with jbd2_journal_reserve().
+ * This attaches @handle to the running transaction (or creates one if there's
+ * not transaction running). Unlike jbd2_journal_start() this function cannot
+ * block on journal commit, checkpointing, or similar stuff. It can block on
+ * memory allocation or frozen journal though.
+ *
+ * Return 0 on success, non-zero on error - handle is freed in that case.
+ */
+int jbd2_journal_start_reserved(handle_t *handle, unsigned int type,
+				unsigned int line_no)
+{
+	journal_t *journal = handle->h_journal;
+	int ret = -EIO;
+
+	if (WARN_ON(!handle->h_reserved)) {
+		/* Someone passed in normal handle? Just stop it. */
+		jbd2_journal_stop(handle);
+		return ret;
+	}
+	/*
+	 * Usefulness of mixing of reserved and unreserved handles is
+	 * questionable. So far nobody seems to need it so just error out.
+	 */
+	if (WARN_ON(current->journal_info)) {
+		jbd2_journal_free_reserved(handle);
+		return ret;
+	}
+
+	handle->h_journal = NULL;
+	/*
+	 * GFP_NOFS is here because callers are likely from writeback or
+	 * similarly constrained call sites
+	 */
+	ret = start_this_handle(journal, handle, GFP_NOFS);
+	if (ret < 0)
+		jbd2_journal_free_reserved(handle);
+	handle->h_type = type;
+	handle->h_line_no = line_no;
+	return ret;
+}
+EXPORT_SYMBOL(jbd2_journal_start_reserved);
 
 /**
  * int jbd2_journal_extend() - extend buffer credits.
@@ -423,49 +545,53 @@ EXPORT_SYMBOL(jbd2_journal_start);
 int jbd2_journal_extend(handle_t *handle, int nblocks)
 {
 	transaction_t *transaction = handle->h_transaction;
-	journal_t *journal = transaction->t_journal;
+	journal_t *journal;
 	int result;
 	int wanted;
 
-	result = -EIO;
+	WARN_ON(!transaction);
 	if (is_handle_aborted(handle))
-		goto out;
+		return -EROFS;
+	journal = transaction->t_journal;
 
 	result = 1;
 
 	read_lock(&journal->j_state_lock);
 
 	/* Don't extend a locked-down transaction! */
-	if (handle->h_transaction->t_state != T_RUNNING) {
+	if (transaction->t_state != T_RUNNING) {
 		jbd_debug(3, "denied handle %p %d blocks: "
 			  "transaction not running\n", handle, nblocks);
 		goto error_out;
 	}
 
 	spin_lock(&transaction->t_handle_lock);
-	wanted = atomic_read(&transaction->t_outstanding_credits) + nblocks;
+	wanted = atomic_add_return(nblocks,
+				   &transaction->t_outstanding_credits);
 
 	if (wanted > journal->j_max_transaction_buffers) {
 		jbd_debug(3, "denied handle %p %d blocks: "
 			  "transaction too large\n", handle, nblocks);
+		atomic_sub(nblocks, &transaction->t_outstanding_credits);
 		goto unlock;
 	}
 
-	if (wanted > __jbd2_log_space_left(journal)) {
+	if (wanted + (wanted >> JBD2_CONTROL_BLOCKS_SHIFT) >
+	    jbd2_log_space_left(journal)) {
 		jbd_debug(3, "denied handle %p %d blocks: "
 			  "insufficient log space\n", handle, nblocks);
+		atomic_sub(nblocks, &transaction->t_outstanding_credits);
 		goto unlock;
 	}
 
 	trace_jbd2_handle_extend(journal->j_fs_dev->bd_dev,
-				 handle->h_transaction->t_tid,
+				 transaction->t_tid,
 				 handle->h_type, handle->h_line_no,
 				 handle->h_buffer_credits,
 				 nblocks);
 
 	handle->h_buffer_credits += nblocks;
 	handle->h_requested_credits += nblocks;
-	atomic_add(nblocks, &transaction->t_outstanding_credits);
 	result = 0;
 
 	jbd_debug(3, "extended handle %p by %d\n", handle, nblocks);
@@ -473,7 +599,6 @@ unlock:
 	spin_unlock(&transaction->t_handle_lock);
 error_out:
 	read_unlock(&journal->j_state_lock);
-out:
 	return result;
 }
 
@@ -490,19 +615,22 @@ out:
  * to a running handle, a call to jbd2_journal_restart will commit the
  * handle's transaction so far and reattach the handle to a new
  * transaction capabable of guaranteeing the requested number of
- * credits.
+ * credits. We preserve reserved handle if there's any attached to the
+ * passed in handle.
  */
 int jbd2__journal_restart(handle_t *handle, int nblocks, gfp_t gfp_mask)
 {
 	transaction_t *transaction = handle->h_transaction;
-	journal_t *journal = transaction->t_journal;
+	journal_t *journal;
 	tid_t		tid;
 	int		need_to_start, ret;
 
+	WARN_ON(!transaction);
 	/* If we've had an abort of any type, don't even think about
 	 * actually doing the restart! */
 	if (is_handle_aborted(handle))
 		return 0;
+	journal = transaction->t_journal;
 
 	/*
 	 * First unlink the handle from its current transaction, and start the
@@ -515,12 +643,18 @@ int jbd2__journal_restart(handle_t *handle, int nblocks, gfp_t gfp_mask)
 	spin_lock(&transaction->t_handle_lock);
 	atomic_sub(handle->h_buffer_credits,
 		   &transaction->t_outstanding_credits);
+	if (handle->h_rsv_handle) {
+		sub_reserved_credits(journal,
+				     handle->h_rsv_handle->h_buffer_credits);
+	}
 	if (atomic_dec_and_test(&transaction->t_updates))
 		wake_up(&journal->j_wait_updates);
+	tid = transaction->t_tid;
 	spin_unlock(&transaction->t_handle_lock);
+	handle->h_transaction = NULL;
+	current->journal_info = NULL;
 
 	jbd_debug(2, "restarting handle %p\n", handle);
-	tid = transaction->t_tid;
 	need_to_start = !tid_geq(journal->j_commit_request, tid);
 	read_unlock(&journal->j_state_lock);
 	if (need_to_start)
@@ -557,6 +691,14 @@ void jbd2_journal_lock_updates(journal_t *journal)
 	write_lock(&journal->j_state_lock);
 	++journal->j_barrier_count;
 
+	/* Wait until there are no reserved handles */
+	if (atomic_read(&journal->j_reserved_credits)) {
+		write_unlock(&journal->j_state_lock);
+		wait_event(journal->j_wait_reserved,
+			   atomic_read(&journal->j_reserved_credits) == 0);
+		write_lock(&journal->j_state_lock);
+	}
+
 	/* Wait until there are no running updates */
 	while (1) {
 		transaction_t *transaction = journal->j_running_transaction;
@@ -619,6 +761,12 @@ static void warn_dirty_buffer(struct buffer_head *bh)
 	       bdevname(bh->b_bdev, b), (unsigned long long)bh->b_blocknr);
 }
 
+static int sleep_on_shadow_bh(void *word)
+{
+	io_schedule();
+	return 0;
+}
+
 /*
  * If the buffer is already part of the current transaction, then there
  * is nothing we need to do.  If it is already part of a prior
@@ -634,17 +782,16 @@ do_get_write_access(handle_t *handle, struct journal_head *jh,
 			int force_copy)
 {
 	struct buffer_head *bh;
-	transaction_t *transaction;
+	transaction_t *transaction = handle->h_transaction;
 	journal_t *journal;
 	int error;
 	char *frozen_buffer = NULL;
 	int need_copy = 0;
 	unsigned long start_lock, time_lock;
 
+	WARN_ON(!transaction);
 	if (is_handle_aborted(handle))
 		return -EROFS;
-
-	transaction = handle->h_transaction;
 	journal = transaction->t_journal;
 
 	jbd_debug(5, "journal_head %p, force_copy %d\n", jh, force_copy);
@@ -754,41 +901,29 @@ repeat:
 		 * journaled.  If the primary copy is already going to
 		 * disk then we cannot do copy-out here. */
 
-		if (jh->b_jlist == BJ_Shadow) {
-			DEFINE_WAIT_BIT(wait, &bh->b_state, BH_Unshadow);
-			wait_queue_head_t *wqh;
-
-			wqh = bit_waitqueue(&bh->b_state, BH_Unshadow);
-
+		if (buffer_shadow(bh)) {
 			JBUFFER_TRACE(jh, "on shadow: sleep");
 			jbd_unlock_bh_state(bh);
-			/* commit wakes up all shadow buffers after IO */
-			for ( ; ; ) {
-				prepare_to_wait(wqh, &wait.wait,
-						TASK_UNINTERRUPTIBLE);
-				if (jh->b_jlist != BJ_Shadow)
-					break;
-				schedule();
-			}
-			finish_wait(wqh, &wait.wait);
+			wait_on_bit(&bh->b_state, BH_Shadow,
+				    sleep_on_shadow_bh, TASK_UNINTERRUPTIBLE);
 			goto repeat;
 		}
 
-		/* Only do the copy if the currently-owning transaction
-		 * still needs it.  If it is on the Forget list, the
-		 * committing transaction is past that stage.  The
-		 * buffer had better remain locked during the kmalloc,
-		 * but that should be true --- we hold the journal lock
-		 * still and the buffer is already on the BUF_JOURNAL
-		 * list so won't be flushed.
+		/*
+		 * Only do the copy if the currently-owning transaction still
+		 * needs it. If buffer isn't on BJ_Metadata list, the
+		 * committing transaction is past that stage (here we use the
+		 * fact that BH_Shadow is set under bh_state lock together with
+		 * refiling to BJ_Shadow list and at this point we know the
+		 * buffer doesn't have BH_Shadow set).
 		 *
 		 * Subtle point, though: if this is a get_undo_access,
 		 * then we will be relying on the frozen_data to contain
 		 * the new value of the committed_data record after the
 		 * transaction, so we HAVE to force the frozen_data copy
-		 * in that case. */
-
-		if (jh->b_jlist != BJ_Forget || force_copy) {
+		 * in that case.
+		 */
+		if (jh->b_jlist == BJ_Metadata || force_copy) {
 			JBUFFER_TRACE(jh, "generate frozen data");
 			if (!frozen_buffer) {
 				JBUFFER_TRACE(jh, "allocate memory for buffer");
@@ -915,14 +1050,16 @@ int jbd2_journal_get_write_access(handle_t *handle, struct buffer_head *bh)
 int jbd2_journal_get_create_access(handle_t *handle, struct buffer_head *bh)
 {
 	transaction_t *transaction = handle->h_transaction;
-	journal_t *journal = transaction->t_journal;
+	journal_t *journal;
 	struct journal_head *jh = jbd2_journal_add_journal_head(bh);
 	int err;
 
 	jbd_debug(5, "journal_head %p\n", jh);
+	WARN_ON(!transaction);
 	err = -EROFS;
 	if (is_handle_aborted(handle))
 		goto out;
+	journal = transaction->t_journal;
 	err = 0;
 
 	JBUFFER_TRACE(jh, "entry");
@@ -1128,12 +1265,14 @@ void jbd2_buffer_abort_trigger(struct journal_head *jh,
 int jbd2_journal_dirty_metadata(handle_t *handle, struct buffer_head *bh)
 {
 	transaction_t *transaction = handle->h_transaction;
-	journal_t *journal = transaction->t_journal;
+	journal_t *journal;
 	struct journal_head *jh;
 	int ret = 0;
 
+	WARN_ON(!transaction);
 	if (is_handle_aborted(handle))
-		goto out;
+		return -EROFS;
+	journal = transaction->t_journal;
 	jh = jbd2_journal_grab_journal_head(bh);
 	if (!jh) {
 		ret = -EUCLEAN;
@@ -1227,7 +1366,7 @@ int jbd2_journal_dirty_metadata(handle_t *handle, struct buffer_head *bh)
 
 	JBUFFER_TRACE(jh, "file as BJ_Metadata");
 	spin_lock(&journal->j_list_lock);
-	__jbd2_journal_file_buffer(jh, handle->h_transaction, BJ_Metadata);
+	__jbd2_journal_file_buffer(jh, transaction, BJ_Metadata);
 	spin_unlock(&journal->j_list_lock);
 out_unlock_bh:
 	jbd_unlock_bh_state(bh);
@@ -1258,12 +1397,17 @@ out:
 int jbd2_journal_forget (handle_t *handle, struct buffer_head *bh)
 {
 	transaction_t *transaction = handle->h_transaction;
-	journal_t *journal = transaction->t_journal;
+	journal_t *journal;
 	struct journal_head *jh;
 	int drop_reserve = 0;
 	int err = 0;
 	int was_modified = 0;
 
+	WARN_ON(!transaction);
+	if (is_handle_aborted(handle))
+		return -EROFS;
+	journal = transaction->t_journal;
+
 	BUFFER_TRACE(bh, "entry");
 
 	jbd_lock_bh_state(bh);
@@ -1290,7 +1434,7 @@ int jbd2_journal_forget (handle_t *handle, struct buffer_head *bh)
 	 */
 	jh->b_modified = 0;
 
-	if (jh->b_transaction == handle->h_transaction) {
+	if (jh->b_transaction == transaction) {
 		J_ASSERT_JH(jh, !jh->b_frozen_data);
 
 		/* If we are forgetting a buffer which is already part
@@ -1385,19 +1529,21 @@ drop:
 int jbd2_journal_stop(handle_t *handle)
 {
 	transaction_t *transaction = handle->h_transaction;
-	journal_t *journal = transaction->t_journal;
-	int err, wait_for_commit = 0;
+	journal_t *journal;
+	int err = 0, wait_for_commit = 0;
 	tid_t tid;
 	pid_t pid;
 
+	if (!transaction)
+		goto free_and_exit;
+	journal = transaction->t_journal;
+
 	J_ASSERT(journal_current_handle() == handle);
 
 	if (is_handle_aborted(handle))
 		err = -EIO;
-	else {
+	else
 		J_ASSERT(atomic_read(&transaction->t_updates) > 0);
-		err = 0;
-	}
 
 	if (--handle->h_ref > 0) {
 		jbd_debug(4, "h_ref %d -> %d\n", handle->h_ref + 1,
@@ -1407,7 +1553,7 @@ int jbd2_journal_stop(handle_t *handle)
 
 	jbd_debug(4, "Handle %p going down\n", handle);
 	trace_jbd2_handle_stats(journal->j_fs_dev->bd_dev,
-				handle->h_transaction->t_tid,
+				transaction->t_tid,
 				handle->h_type, handle->h_line_no,
 				jiffies - handle->h_start_jiffies,
 				handle->h_sync, handle->h_requested_credits,
@@ -1518,33 +1664,13 @@ int jbd2_journal_stop(handle_t *handle)
 
 	lock_map_release(&handle->h_lockdep_map);
 
+	if (handle->h_rsv_handle)
+		jbd2_journal_free_reserved(handle->h_rsv_handle);
+free_and_exit:
 	jbd2_free_handle(handle);
 	return err;
 }
 
-/**
- * int jbd2_journal_force_commit() - force any uncommitted transactions
- * @journal: journal to force
- *
- * For synchronous operations: force any uncommitted transactions
- * to disk.  May seem kludgy, but it reuses all the handle batching
- * code in a very simple manner.
- */
-int jbd2_journal_force_commit(journal_t *journal)
-{
-	handle_t *handle;
-	int ret;
-
-	handle = jbd2_journal_start(journal, 1);
-	if (IS_ERR(handle)) {
-		ret = PTR_ERR(handle);
-	} else {
-		handle->h_sync = 1;
-		ret = jbd2_journal_stop(handle);
-	}
-	return ret;
-}
-
 /*
  *
  * List management code snippets: various functions for manipulating the
@@ -1601,10 +1727,10 @@ __blist_del_buffer(struct journal_head **list, struct journal_head *jh)
  * Remove a buffer from the appropriate transaction list.
  *
  * Note that this function can *change* the value of
- * bh->b_transaction->t_buffers, t_forget, t_iobuf_list, t_shadow_list,
- * t_log_list or t_reserved_list.  If the caller is holding onto a copy of one
- * of these pointers, it could go bad.  Generally the caller needs to re-read
- * the pointer from the transaction_t.
+ * bh->b_transaction->t_buffers, t_forget, t_shadow_list, t_log_list or
+ * t_reserved_list.  If the caller is holding onto a copy of one of these
+ * pointers, it could go bad.  Generally the caller needs to re-read the
+ * pointer from the transaction_t.
  *
  * Called under j_list_lock.
  */
@@ -1634,15 +1760,9 @@ static void __jbd2_journal_temp_unlink_buffer(struct journal_head *jh)
 	case BJ_Forget:
 		list = &transaction->t_forget;
 		break;
-	case BJ_IO:
-		list = &transaction->t_iobuf_list;
-		break;
 	case BJ_Shadow:
 		list = &transaction->t_shadow_list;
 		break;
-	case BJ_LogCtl:
-		list = &transaction->t_log_list;
-		break;
 	case BJ_Reserved:
 		list = &transaction->t_reserved_list;
 		break;
@@ -2034,18 +2154,23 @@ zap_buffer_unlocked:
  * void jbd2_journal_invalidatepage()
  * @journal: journal to use for flush...
  * @page:    page to flush
- * @offset:  length of page to invalidate.
+ * @offset:  start of the range to invalidate
+ * @length:  length of the range to invalidate
  *
- * Reap page buffers containing data after offset in page. Can return -EBUSY
- * if buffers are part of the committing transaction and the page is straddling
- * i_size. Caller then has to wait for current commit and try again.
+ * Reap page buffers containing data after in the specified range in page.
+ * Can return -EBUSY if buffers are part of the committing transaction and
+ * the page is straddling i_size. Caller then has to wait for current commit
+ * and try again.
  */
 int jbd2_journal_invalidatepage(journal_t *journal,
 				struct page *page,
-				unsigned long offset)
+				unsigned int offset,
+				unsigned int length)
 {
 	struct buffer_head *head, *bh, *next;
+	unsigned int stop = offset + length;
 	unsigned int curr_off = 0;
+	int partial_page = (offset || length < PAGE_CACHE_SIZE);
 	int may_free = 1;
 	int ret = 0;
 
@@ -2054,6 +2179,8 @@ int jbd2_journal_invalidatepage(journal_t *journal,
 	if (!page_has_buffers(page))
 		return 0;
 
+	BUG_ON(stop > PAGE_CACHE_SIZE || stop < length);
+
 	/* We will potentially be playing with lists other than just the
 	 * data lists (especially for journaled data mode), so be
 	 * cautious in our locking. */
@@ -2063,10 +2190,13 @@ int jbd2_journal_invalidatepage(journal_t *journal,
 		unsigned int next_off = curr_off + bh->b_size;
 		next = bh->b_this_page;
 
+		if (next_off > stop)
+			return 0;
+
 		if (offset <= curr_off) {
 			/* This block is wholly outside the truncation point */
 			lock_buffer(bh);
-			ret = journal_unmap_buffer(journal, bh, offset > 0);
+			ret = journal_unmap_buffer(journal, bh, partial_page);
 			unlock_buffer(bh);
 			if (ret < 0)
 				return ret;
@@ -2077,7 +2207,7 @@ int jbd2_journal_invalidatepage(journal_t *journal,
 
 	} while (bh != head);
 
-	if (!offset) {
+	if (!partial_page) {
 		if (may_free && try_to_free_buffers(page))
 			J_ASSERT(!page_has_buffers(page));
 	}
@@ -2138,15 +2268,9 @@ void __jbd2_journal_file_buffer(struct journal_head *jh,
 	case BJ_Forget:
 		list = &transaction->t_forget;
 		break;
-	case BJ_IO:
-		list = &transaction->t_iobuf_list;
-		break;
 	case BJ_Shadow:
 		list = &transaction->t_shadow_list;
 		break;
-	case BJ_LogCtl:
-		list = &transaction->t_log_list;
-		break;
 	case BJ_Reserved:
 		list = &transaction->t_reserved_list;
 		break;
@@ -2248,10 +2372,12 @@ void jbd2_journal_refile_buffer(journal_t *journal, struct journal_head *jh)
 int jbd2_journal_file_inode(handle_t *handle, struct jbd2_inode *jinode)
 {
 	transaction_t *transaction = handle->h_transaction;
-	journal_t *journal = transaction->t_journal;
+	journal_t *journal;
 
+	WARN_ON(!transaction);
 	if (is_handle_aborted(handle))
-		return -EIO;
+		return -EROFS;
+	journal = transaction->t_journal;
 
 	jbd_debug(4, "Adding inode %lu, tid:%d\n", jinode->i_vfs_inode->i_ino,
 			transaction->t_tid);