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, 785 insertions, 966 deletions

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index d6382b89ecbd..0188e65e1f58 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -132,12 +132,12 @@ static inline int ext4_begin_ordered_truncate(struct inode *inode,
 						   new_size);
 }
 
-static void ext4_invalidatepage(struct page *page, unsigned long offset);
+static void ext4_invalidatepage(struct page *page, unsigned int offset,
+				unsigned int length);
 static int __ext4_journalled_writepage(struct page *page, unsigned int len);
 static int ext4_bh_delay_or_unwritten(handle_t *handle, struct buffer_head *bh);
-static int ext4_discard_partial_page_buffers_no_lock(handle_t *handle,
-		struct inode *inode, struct page *page, loff_t from,
-		loff_t length, int flags);
+static int ext4_meta_trans_blocks(struct inode *inode, int lblocks,
+				  int pextents);
 
 /*
  * Test whether an inode is a fast symlink.
@@ -215,7 +215,8 @@ void ext4_evict_inode(struct inode *inode)
 			filemap_write_and_wait(&inode->i_data);
 		}
 		truncate_inode_pages(&inode->i_data, 0);
-		ext4_ioend_shutdown(inode);
+
+		WARN_ON(atomic_read(&EXT4_I(inode)->i_ioend_count));
 		goto no_delete;
 	}
 
@@ -225,8 +226,8 @@ void ext4_evict_inode(struct inode *inode)
 	if (ext4_should_order_data(inode))
 		ext4_begin_ordered_truncate(inode, 0);
 	truncate_inode_pages(&inode->i_data, 0);
-	ext4_ioend_shutdown(inode);
 
+	WARN_ON(atomic_read(&EXT4_I(inode)->i_ioend_count));
 	if (is_bad_inode(inode))
 		goto no_delete;
 
@@ -423,66 +424,6 @@ static int __check_block_validity(struct inode *inode, const char *func,
 #define check_block_validity(inode, map)	\
 	__check_block_validity((inode), __func__, __LINE__, (map))
 
-/*
- * Return the number of contiguous dirty pages in a given inode
- * starting at page frame idx.
- */
-static pgoff_t ext4_num_dirty_pages(struct inode *inode, pgoff_t idx,
-				    unsigned int max_pages)
-{
-	struct address_space *mapping = inode->i_mapping;
-	pgoff_t	index;
-	struct pagevec pvec;
-	pgoff_t num = 0;
-	int i, nr_pages, done = 0;
-
-	if (max_pages == 0)
-		return 0;
-	pagevec_init(&pvec, 0);
-	while (!done) {
-		index = idx;
-		nr_pages = pagevec_lookup_tag(&pvec, mapping, &index,
-					      PAGECACHE_TAG_DIRTY,
-					      (pgoff_t)PAGEVEC_SIZE);
-		if (nr_pages == 0)
-			break;
-		for (i = 0; i < nr_pages; i++) {
-			struct page *page = pvec.pages[i];
-			struct buffer_head *bh, *head;
-
-			lock_page(page);
-			if (unlikely(page->mapping != mapping) ||
-			    !PageDirty(page) ||
-			    PageWriteback(page) ||
-			    page->index != idx) {
-				done = 1;
-				unlock_page(page);
-				break;
-			}
-			if (page_has_buffers(page)) {
-				bh = head = page_buffers(page);
-				do {
-					if (!buffer_delay(bh) &&
-					    !buffer_unwritten(bh))
-						done = 1;
-					bh = bh->b_this_page;
-				} while (!done && (bh != head));
-			}
-			unlock_page(page);
-			if (done)
-				break;
-			idx++;
-			num++;
-			if (num >= max_pages) {
-				done = 1;
-				break;
-			}
-		}
-		pagevec_release(&pvec);
-	}
-	return num;
-}
-
 #ifdef ES_AGGRESSIVE_TEST
 static void ext4_map_blocks_es_recheck(handle_t *handle,
 				       struct inode *inode,
@@ -573,6 +514,8 @@ int ext4_map_blocks(handle_t *handle, struct inode *inode,
 		  "logical block %lu\n", inode->i_ino, flags, map->m_len,
 		  (unsigned long) map->m_lblk);
 
+	ext4_es_lru_add(inode);
+
 	/* Lookup extent status tree firstly */
 	if (ext4_es_lookup_extent(inode, map->m_lblk, &es)) {
 		if (ext4_es_is_written(&es) || ext4_es_is_unwritten(&es)) {
@@ -1118,10 +1061,13 @@ static int ext4_write_end(struct file *file,
 		}
 	}
 
-	if (ext4_has_inline_data(inode))
-		copied = ext4_write_inline_data_end(inode, pos, len,
-						    copied, page);
-	else
+	if (ext4_has_inline_data(inode)) {
+		ret = ext4_write_inline_data_end(inode, pos, len,
+						 copied, page);
+		if (ret < 0)
+			goto errout;
+		copied = ret;
+	} else
 		copied = block_write_end(file, mapping, pos,
 					 len, copied, page, fsdata);
 
@@ -1157,8 +1103,6 @@ static int ext4_write_end(struct file *file,
 	if (i_size_changed)
 		ext4_mark_inode_dirty(handle, inode);
 
-	if (copied < 0)
-		ret = copied;
 	if (pos + len > inode->i_size && ext4_can_truncate(inode))
 		/* if we have allocated more blocks and copied
 		 * less. We will have blocks allocated outside
@@ -1415,21 +1359,28 @@ static void ext4_da_release_space(struct inode *inode, int to_free)
 }
 
 static void ext4_da_page_release_reservation(struct page *page,
-					     unsigned long offset)
+					     unsigned int offset,
+					     unsigned int length)
 {
 	int to_release = 0;
 	struct buffer_head *head, *bh;
 	unsigned int curr_off = 0;
 	struct inode *inode = page->mapping->host;
 	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+	unsigned int stop = offset + length;
 	int num_clusters;
 	ext4_fsblk_t lblk;
 
+	BUG_ON(stop > PAGE_CACHE_SIZE || stop < length);
+
 	head = page_buffers(page);
 	bh = head;
 	do {
 		unsigned int next_off = curr_off + bh->b_size;
 
+		if (next_off > stop)
+			break;
+
 		if ((offset <= curr_off) && (buffer_delay(bh))) {
 			to_release++;
 			clear_buffer_delay(bh);
@@ -1460,140 +1411,43 @@ static void ext4_da_page_release_reservation(struct page *page,
  * Delayed allocation stuff
  */
 
-/*
- * mpage_da_submit_io - walks through extent of pages and try to write
- * them with writepage() call back
- *
- * @mpd->inode: inode
- * @mpd->first_page: first page of the extent
- * @mpd->next_page: page after the last page of the extent
- *
- * By the time mpage_da_submit_io() is called we expect all blocks
- * to be allocated. this may be wrong if allocation failed.
- *
- * As pages are already locked by write_cache_pages(), we can't use it
- */
-static int mpage_da_submit_io(struct mpage_da_data *mpd,
-			      struct ext4_map_blocks *map)
-{
-	struct pagevec pvec;
-	unsigned long index, end;
-	int ret = 0, err, nr_pages, i;
-	struct inode *inode = mpd->inode;
-	struct address_space *mapping = inode->i_mapping;
-	loff_t size = i_size_read(inode);
-	unsigned int len, block_start;
-	struct buffer_head *bh, *page_bufs = NULL;
-	sector_t pblock = 0, cur_logical = 0;
-	struct ext4_io_submit io_submit;
+struct mpage_da_data {
+	struct inode *inode;
+	struct writeback_control *wbc;
 
-	BUG_ON(mpd->next_page <= mpd->first_page);
-	memset(&io_submit, 0, sizeof(io_submit));
+	pgoff_t first_page;	/* The first page to write */
+	pgoff_t next_page;	/* Current page to examine */
+	pgoff_t last_page;	/* Last page to examine */
 	/*
-	 * We need to start from the first_page to the next_page - 1
-	 * to make sure we also write the mapped dirty buffer_heads.
-	 * If we look at mpd->b_blocknr we would only be looking
-	 * at the currently mapped buffer_heads.
+	 * Extent to map - this can be after first_page because that can be
+	 * fully mapped. We somewhat abuse m_flags to store whether the extent
+	 * is delalloc or unwritten.
 	 */
-	index = mpd->first_page;
-	end = mpd->next_page - 1;
-
-	pagevec_init(&pvec, 0);
-	while (index <= end) {
-		nr_pages = pagevec_lookup(&pvec, mapping, index, PAGEVEC_SIZE);
-		if (nr_pages == 0)
-			break;
-		for (i = 0; i < nr_pages; i++) {
-			int skip_page = 0;
-			struct page *page = pvec.pages[i];
-
-			index = page->index;
-			if (index > end)
-				break;
-
-			if (index == size >> PAGE_CACHE_SHIFT)
-				len = size & ~PAGE_CACHE_MASK;
-			else
-				len = PAGE_CACHE_SIZE;
-			if (map) {
-				cur_logical = index << (PAGE_CACHE_SHIFT -
-							inode->i_blkbits);
-				pblock = map->m_pblk + (cur_logical -
-							map->m_lblk);
-			}
-			index++;
-
-			BUG_ON(!PageLocked(page));
-			BUG_ON(PageWriteback(page));
-
-			bh = page_bufs = page_buffers(page);
-			block_start = 0;
-			do {
-				if (map && (cur_logical >= map->m_lblk) &&
-				    (cur_logical <= (map->m_lblk +
-						     (map->m_len - 1)))) {
-					if (buffer_delay(bh)) {
-						clear_buffer_delay(bh);
-						bh->b_blocknr = pblock;
-					}
-					if (buffer_unwritten(bh) ||
-					    buffer_mapped(bh))
-						BUG_ON(bh->b_blocknr != pblock);
-					if (map->m_flags & EXT4_MAP_UNINIT)
-						set_buffer_uninit(bh);
-					clear_buffer_unwritten(bh);
-				}
-
-				/*
-				 * skip page if block allocation undone and
-				 * block is dirty
-				 */
-				if (ext4_bh_delay_or_unwritten(NULL, bh))
-					skip_page = 1;
-				bh = bh->b_this_page;
-				block_start += bh->b_size;
-				cur_logical++;
-				pblock++;
-			} while (bh != page_bufs);
-
-			if (skip_page) {
-				unlock_page(page);
-				continue;
-			}
-
-			clear_page_dirty_for_io(page);
-			err = ext4_bio_write_page(&io_submit, page, len,
-						  mpd->wbc);
-			if (!err)
-				mpd->pages_written++;
-			/*
-			 * In error case, we have to continue because
-			 * remaining pages are still locked
-			 */
-			if (ret == 0)
-				ret = err;
-		}
-		pagevec_release(&pvec);
-	}
-	ext4_io_submit(&io_submit);
-	return ret;
-}
+	struct ext4_map_blocks map;
+	struct ext4_io_submit io_submit;	/* IO submission data */
+};
 
-static void ext4_da_block_invalidatepages(struct mpage_da_data *mpd)
+static void mpage_release_unused_pages(struct mpage_da_data *mpd,
+				       bool invalidate)
 {
 	int nr_pages, i;
 	pgoff_t index, end;
 	struct pagevec pvec;
 	struct inode *inode = mpd->inode;
 	struct address_space *mapping = inode->i_mapping;
-	ext4_lblk_t start, last;
+
+	/* This is necessary when next_page == 0. */
+	if (mpd->first_page >= mpd->next_page)
+		return;
 
 	index = mpd->first_page;
 	end   = mpd->next_page - 1;
-
-	start = index << (PAGE_CACHE_SHIFT - inode->i_blkbits);
-	last = end << (PAGE_CACHE_SHIFT - inode->i_blkbits);
-	ext4_es_remove_extent(inode, start, last - start + 1);
+	if (invalidate) {
+		ext4_lblk_t start, last;
+		start = index << (PAGE_CACHE_SHIFT - inode->i_blkbits);
+		last = end << (PAGE_CACHE_SHIFT - inode->i_blkbits);
+		ext4_es_remove_extent(inode, start, last - start + 1);
+	}
 
 	pagevec_init(&pvec, 0);
 	while (index <= end) {
@@ -1606,14 +1460,15 @@ static void ext4_da_block_invalidatepages(struct mpage_da_data *mpd)
 				break;
 			BUG_ON(!PageLocked(page));
 			BUG_ON(PageWriteback(page));
-			block_invalidatepage(page, 0);
-			ClearPageUptodate(page);
+			if (invalidate) {
+				block_invalidatepage(page, 0, PAGE_CACHE_SIZE);
+				ClearPageUptodate(page);
+			}
 			unlock_page(page);
 		}
 		index = pvec.pages[nr_pages - 1]->index + 1;
 		pagevec_release(&pvec);
 	}
-	return;
 }
 
 static void ext4_print_free_blocks(struct inode *inode)
@@ -1642,215 +1497,6 @@ static void ext4_print_free_blocks(struct inode *inode)
 	return;
 }
 
-/*
- * mpage_da_map_and_submit - go through given space, map them
- *       if necessary, and then submit them for I/O
- *
- * @mpd - bh describing space
- *
- * The function skips space we know is already mapped to disk blocks.
- *
- */
-static void mpage_da_map_and_submit(struct mpage_da_data *mpd)
-{
-	int err, blks, get_blocks_flags;
-	struct ext4_map_blocks map, *mapp = NULL;
-	sector_t next = mpd->b_blocknr;
-	unsigned max_blocks = mpd->b_size >> mpd->inode->i_blkbits;
-	loff_t disksize = EXT4_I(mpd->inode)->i_disksize;
-	handle_t *handle = NULL;
-
-	/*
-	 * If the blocks are mapped already, or we couldn't accumulate
-	 * any blocks, then proceed immediately to the submission stage.
-	 */
-	if ((mpd->b_size == 0) ||
-	    ((mpd->b_state  & (1 << BH_Mapped)) &&
-	     !(mpd->b_state & (1 << BH_Delay)) &&
-	     !(mpd->b_state & (1 << BH_Unwritten))))
-		goto submit_io;
-
-	handle = ext4_journal_current_handle();
-	BUG_ON(!handle);
-
-	/*
-	 * Call ext4_map_blocks() to allocate any delayed allocation
-	 * blocks, or to convert an uninitialized extent to be
-	 * initialized (in the case where we have written into
-	 * one or more preallocated blocks).
-	 *
-	 * We pass in the magic EXT4_GET_BLOCKS_DELALLOC_RESERVE to
-	 * indicate that we are on the delayed allocation path.  This
-	 * affects functions in many different parts of the allocation
-	 * call path.  This flag exists primarily because we don't
-	 * want to change *many* call functions, so ext4_map_blocks()
-	 * will set the EXT4_STATE_DELALLOC_RESERVED flag once the
-	 * inode's allocation semaphore is taken.
-	 *
-	 * If the blocks in questions were delalloc blocks, set
-	 * EXT4_GET_BLOCKS_DELALLOC_RESERVE so the delalloc accounting
-	 * variables are updated after the blocks have been allocated.
-	 */
-	map.m_lblk = next;
-	map.m_len = max_blocks;
-	/*
-	 * We're in delalloc path and it is possible that we're going to
-	 * need more metadata blocks than previously reserved. However
-	 * we must not fail because we're in writeback and there is
-	 * nothing we can do about it so it might result in data loss.
-	 * So use reserved blocks to allocate metadata if possible.
-	 */
-	get_blocks_flags = EXT4_GET_BLOCKS_CREATE |
-			   EXT4_GET_BLOCKS_METADATA_NOFAIL;
-	if (ext4_should_dioread_nolock(mpd->inode))
-		get_blocks_flags |= EXT4_GET_BLOCKS_IO_CREATE_EXT;
-	if (mpd->b_state & (1 << BH_Delay))
-		get_blocks_flags |= EXT4_GET_BLOCKS_DELALLOC_RESERVE;
-
-
-	blks = ext4_map_blocks(handle, mpd->inode, &map, get_blocks_flags);
-	if (blks < 0) {
-		struct super_block *sb = mpd->inode->i_sb;
-
-		err = blks;
-		/*
-		 * If get block returns EAGAIN or ENOSPC and there
-		 * appears to be free blocks we will just let
-		 * mpage_da_submit_io() unlock all of the pages.
-		 */
-		if (err == -EAGAIN)
-			goto submit_io;
-
-		if (err == -ENOSPC && ext4_count_free_clusters(sb)) {
-			mpd->retval = err;
-			goto submit_io;
-		}
-
-		/*
-		 * get block failure will cause us to loop in
-		 * writepages, because a_ops->writepage won't be able
-		 * to make progress. The page will be redirtied by
-		 * writepage and writepages will again try to write
-		 * the same.
-		 */
-		if (!(EXT4_SB(sb)->s_mount_flags & EXT4_MF_FS_ABORTED)) {
-			ext4_msg(sb, KERN_CRIT,
-				 "delayed block allocation failed for inode %lu "
-				 "at logical offset %llu with max blocks %zd "
-				 "with error %d", mpd->inode->i_ino,
-				 (unsigned long long) next,
-				 mpd->b_size >> mpd->inode->i_blkbits, err);
-			ext4_msg(sb, KERN_CRIT,
-				"This should not happen!! Data will be lost");
-			if (err == -ENOSPC)
-				ext4_print_free_blocks(mpd->inode);
-		}
-		/* invalidate all the pages */
-		ext4_da_block_invalidatepages(mpd);
-
-		/* Mark this page range as having been completed */
-		mpd->io_done = 1;
-		return;
-	}
-	BUG_ON(blks == 0);
-
-	mapp = &map;
-	if (map.m_flags & EXT4_MAP_NEW) {
-		struct block_device *bdev = mpd->inode->i_sb->s_bdev;
-		int i;
-
-		for (i = 0; i < map.m_len; i++)
-			unmap_underlying_metadata(bdev, map.m_pblk + i);
-	}
-
-	/*
-	 * Update on-disk size along with block allocation.
-	 */
-	disksize = ((loff_t) next + blks) << mpd->inode->i_blkbits;
-	if (disksize > i_size_read(mpd->inode))
-		disksize = i_size_read(mpd->inode);
-	if (disksize > EXT4_I(mpd->inode)->i_disksize) {
-		ext4_update_i_disksize(mpd->inode, disksize);
-		err = ext4_mark_inode_dirty(handle, mpd->inode);
-		if (err)
-			ext4_error(mpd->inode->i_sb,
-				   "Failed to mark inode %lu dirty",
-				   mpd->inode->i_ino);
-	}
-
-submit_io:
-	mpage_da_submit_io(mpd, mapp);
-	mpd->io_done = 1;
-}
-
-#define BH_FLAGS ((1 << BH_Uptodate) | (1 << BH_Mapped) | \
-		(1 << BH_Delay) | (1 << BH_Unwritten))
-
-/*
- * mpage_add_bh_to_extent - try to add one more block to extent of blocks
- *
- * @mpd->lbh - extent of blocks
- * @logical - logical number of the block in the file
- * @b_state - b_state of the buffer head added
- *
- * the function is used to collect contig. blocks in same state
- */
-static void mpage_add_bh_to_extent(struct mpage_da_data *mpd, sector_t logical,
-				   unsigned long b_state)
-{
-	sector_t next;
-	int blkbits = mpd->inode->i_blkbits;
-	int nrblocks = mpd->b_size >> blkbits;
-
-	/*
-	 * XXX Don't go larger than mballoc is willing to allocate
-	 * This is a stopgap solution.  We eventually need to fold
-	 * mpage_da_submit_io() into this function and then call
-	 * ext4_map_blocks() multiple times in a loop
-	 */
-	if (nrblocks >= (8*1024*1024 >> blkbits))
-		goto flush_it;
-
-	/* check if the reserved journal credits might overflow */
-	if (!ext4_test_inode_flag(mpd->inode, EXT4_INODE_EXTENTS)) {
-		if (nrblocks >= EXT4_MAX_TRANS_DATA) {
-			/*
-			 * With non-extent format we are limited by the journal
-			 * credit available.  Total credit needed to insert
-			 * nrblocks contiguous blocks is dependent on the
-			 * nrblocks.  So limit nrblocks.
-			 */
-			goto flush_it;
-		}
-	}
-	/*
-	 * First block in the extent
-	 */
-	if (mpd->b_size == 0) {
-		mpd->b_blocknr = logical;
-		mpd->b_size = 1 << blkbits;
-		mpd->b_state = b_state & BH_FLAGS;
-		return;
-	}
-
-	next = mpd->b_blocknr + nrblocks;
-	/*
-	 * Can we merge the block to our big extent?
-	 */
-	if (logical == next && (b_state & BH_FLAGS) == mpd->b_state) {
-		mpd->b_size += 1 << blkbits;
-		return;
-	}
-
-flush_it:
-	/*
-	 * We couldn't merge the block to our extent, so we
-	 * need to flush current  extent and start new one
-	 */
-	mpage_da_map_and_submit(mpd);
-	return;
-}
-
 static int ext4_bh_delay_or_unwritten(handle_t *handle, struct buffer_head *bh)
 {
 	return (buffer_delay(bh) || buffer_unwritten(bh)) && buffer_dirty(bh);
@@ -1883,6 +1529,8 @@ static int ext4_da_map_blocks(struct inode *inode, sector_t iblock,
 		  "logical block %lu\n", inode->i_ino, map->m_len,
 		  (unsigned long) map->m_lblk);
 
+	ext4_es_lru_add(inode);
+
 	/* Lookup extent status tree firstly */
 	if (ext4_es_lookup_extent(inode, iblock, &es)) {
 
@@ -2156,7 +1804,7 @@ out:
  * lock so we have to do some magic.
  *
  * This function can get called via...
- *   - ext4_da_writepages after taking page lock (have journal handle)
+ *   - ext4_writepages after taking page lock (have journal handle)
  *   - journal_submit_inode_data_buffers (no journal handle)
  *   - shrink_page_list via the kswapd/direct reclaim (no journal handle)
  *   - grab_page_cache when doing write_begin (have journal handle)
@@ -2234,76 +1882,405 @@ static int ext4_writepage(struct page *page,
 		 */
 		return __ext4_journalled_writepage(page, len);
 
-	memset(&io_submit, 0, sizeof(io_submit));
+	ext4_io_submit_init(&io_submit, wbc);
+	io_submit.io_end = ext4_init_io_end(inode, GFP_NOFS);
+	if (!io_submit.io_end) {
+		redirty_page_for_writepage(wbc, page);
+		unlock_page(page);
+		return -ENOMEM;
+	}
 	ret = ext4_bio_write_page(&io_submit, page, len, wbc);
 	ext4_io_submit(&io_submit);
+	/* Drop io_end reference we got from init */
+	ext4_put_io_end_defer(io_submit.io_end);
 	return ret;
 }
 
+#define BH_FLAGS ((1 << BH_Unwritten) | (1 << BH_Delay))
+
 /*
- * This is called via ext4_da_writepages() to
- * calculate the total number of credits to reserve to fit
- * a single extent allocation into a single transaction,
- * ext4_da_writpeages() will loop calling this before
- * the block allocation.
+ * mballoc gives us at most this number of blocks...
+ * XXX: That seems to be only a limitation of ext4_mb_normalize_request().
+ * The rest of mballoc seems to handle chunks upto full group size.
  */
+#define MAX_WRITEPAGES_EXTENT_LEN 2048
 
-static int ext4_da_writepages_trans_blocks(struct inode *inode)
+/*
+ * mpage_add_bh_to_extent - try to add bh to extent of blocks to map
+ *
+ * @mpd - extent of blocks
+ * @lblk - logical number of the block in the file
+ * @b_state - b_state of the buffer head added
+ *
+ * the function is used to collect contig. blocks in same state
+ */
+static int mpage_add_bh_to_extent(struct mpage_da_data *mpd, ext4_lblk_t lblk,
+				  unsigned long b_state)
+{
+	struct ext4_map_blocks *map = &mpd->map;
+
+	/* Don't go larger than mballoc is willing to allocate */
+	if (map->m_len >= MAX_WRITEPAGES_EXTENT_LEN)
+		return 0;
+
+	/* First block in the extent? */
+	if (map->m_len == 0) {
+		map->m_lblk = lblk;
+		map->m_len = 1;
+		map->m_flags = b_state & BH_FLAGS;
+		return 1;
+	}
+
+	/* Can we merge the block to our big extent? */
+	if (lblk == map->m_lblk + map->m_len &&
+	    (b_state & BH_FLAGS) == map->m_flags) {
+		map->m_len++;
+		return 1;
+	}
+	return 0;
+}
+
+static bool add_page_bufs_to_extent(struct mpage_da_data *mpd,
+				    struct buffer_head *head,
+				    struct buffer_head *bh,
+				    ext4_lblk_t lblk)
+{
+	struct inode *inode = mpd->inode;
+	ext4_lblk_t blocks = (i_size_read(inode) + (1 << inode->i_blkbits) - 1)
+							>> inode->i_blkbits;
+
+	do {
+		BUG_ON(buffer_locked(bh));
+
+		if (!buffer_dirty(bh) || !buffer_mapped(bh) ||
+		    (!buffer_delay(bh) && !buffer_unwritten(bh)) ||
+		    lblk >= blocks) {
+			/* Found extent to map? */
+			if (mpd->map.m_len)
+				return false;
+			if (lblk >= blocks)
+				return true;
+			continue;
+		}
+		if (!mpage_add_bh_to_extent(mpd, lblk, bh->b_state))
+			return false;
+	} while (lblk++, (bh = bh->b_this_page) != head);
+	return true;
+}
+
+static int mpage_submit_page(struct mpage_da_data *mpd, struct page *page)
 {
-	int max_blocks = EXT4_I(inode)->i_reserved_data_blocks;
+	int len;
+	loff_t size = i_size_read(mpd->inode);
+	int err;
+
+	BUG_ON(page->index != mpd->first_page);
+	if (page->index == size >> PAGE_CACHE_SHIFT)
+		len = size & ~PAGE_CACHE_MASK;
+	else
+		len = PAGE_CACHE_SIZE;
+	clear_page_dirty_for_io(page);
+	err = ext4_bio_write_page(&mpd->io_submit, page, len, mpd->wbc);
+	if (!err)
+		mpd->wbc->nr_to_write--;
+	mpd->first_page++;
 
+	return err;
+}
+
+/*
+ * mpage_map_buffers - update buffers corresponding to changed extent and
+ *		       submit fully mapped pages for IO
+ *
+ * @mpd - description of extent to map, on return next extent to map
+ *
+ * Scan buffers corresponding to changed extent (we expect corresponding pages
+ * to be already locked) and update buffer state according to new extent state.
+ * We map delalloc buffers to their physical location, clear unwritten bits,
+ * and mark buffers as uninit when we perform writes to uninitialized extents
+ * and do extent conversion after IO is finished. If the last page is not fully
+ * mapped, we update @map to the next extent in the last page that needs
+ * mapping. Otherwise we submit the page for IO.
+ */
+static int mpage_map_and_submit_buffers(struct mpage_da_data *mpd)
+{
+	struct pagevec pvec;
+	int nr_pages, i;
+	struct inode *inode = mpd->inode;
+	struct buffer_head *head, *bh;
+	int bpp_bits = PAGE_CACHE_SHIFT - inode->i_blkbits;
+	ext4_lblk_t blocks = (i_size_read(inode) + (1 << inode->i_blkbits) - 1)
+							>> inode->i_blkbits;
+	pgoff_t start, end;
+	ext4_lblk_t lblk;
+	sector_t pblock;
+	int err;
+
+	start = mpd->map.m_lblk >> bpp_bits;
+	end = (mpd->map.m_lblk + mpd->map.m_len - 1) >> bpp_bits;
+	lblk = start << bpp_bits;
+	pblock = mpd->map.m_pblk;
+
+	pagevec_init(&pvec, 0);
+	while (start <= end) {
+		nr_pages = pagevec_lookup(&pvec, inode->i_mapping, start,
+					  PAGEVEC_SIZE);
+		if (nr_pages == 0)
+			break;
+		for (i = 0; i < nr_pages; i++) {
+			struct page *page = pvec.pages[i];
+
+			if (page->index > end)
+				break;
+			/* Upto 'end' pages must be contiguous */
+			BUG_ON(page->index != start);
+			bh = head = page_buffers(page);
+			do {
+				if (lblk < mpd->map.m_lblk)
+					continue;
+				if (lblk >= mpd->map.m_lblk + mpd->map.m_len) {
+					/*
+					 * Buffer after end of mapped extent.
+					 * Find next buffer in the page to map.
+					 */
+					mpd->map.m_len = 0;
+					mpd->map.m_flags = 0;
+					add_page_bufs_to_extent(mpd, head, bh,
+								lblk);
+					pagevec_release(&pvec);
+					return 0;
+				}
+				if (buffer_delay(bh)) {
+					clear_buffer_delay(bh);
+					bh->b_blocknr = pblock++;
+				}
+				clear_buffer_unwritten(bh);
+			} while (++lblk < blocks &&
+				 (bh = bh->b_this_page) != head);
+
+			/*
+			 * FIXME: This is going to break if dioread_nolock
+			 * supports blocksize < pagesize as we will try to
+			 * convert potentially unmapped parts of inode.
+			 */
+			mpd->io_submit.io_end->size += PAGE_CACHE_SIZE;
+			/* Page fully mapped - let IO run! */
+			err = mpage_submit_page(mpd, page);
+			if (err < 0) {
+				pagevec_release(&pvec);
+				return err;
+			}
+			start++;
+		}
+		pagevec_release(&pvec);
+	}
+	/* Extent fully mapped and matches with page boundary. We are done. */
+	mpd->map.m_len = 0;
+	mpd->map.m_flags = 0;
+	return 0;
+}
+
+static int mpage_map_one_extent(handle_t *handle, struct mpage_da_data *mpd)
+{
+	struct inode *inode = mpd->inode;
+	struct ext4_map_blocks *map = &mpd->map;
+	int get_blocks_flags;
+	int err;
+
+	trace_ext4_da_write_pages_extent(inode, map);
 	/*
-	 * With non-extent format the journal credit needed to
-	 * insert nrblocks contiguous block is dependent on
-	 * number of contiguous block. So we will limit
-	 * number of contiguous block to a sane value
+	 * Call ext4_map_blocks() to allocate any delayed allocation blocks, or
+	 * to convert an uninitialized extent to be initialized (in the case
+	 * where we have written into one or more preallocated blocks).  It is
+	 * possible that we're going to need more metadata blocks than
+	 * previously reserved. However we must not fail because we're in
+	 * writeback and there is nothing we can do about it so it might result
+	 * in data loss.  So use reserved blocks to allocate metadata if
+	 * possible.
+	 *
+	 * We pass in the magic EXT4_GET_BLOCKS_DELALLOC_RESERVE if the blocks
+	 * in question are delalloc blocks.  This affects functions in many
+	 * different parts of the allocation call path.  This flag exists
+	 * primarily because we don't want to change *many* call functions, so
+	 * ext4_map_blocks() will set the EXT4_STATE_DELALLOC_RESERVED flag
+	 * once the inode's allocation semaphore is taken.
 	 */
-	if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) &&
-	    (max_blocks > EXT4_MAX_TRANS_DATA))
-		max_blocks = EXT4_MAX_TRANS_DATA;
+	get_blocks_flags = EXT4_GET_BLOCKS_CREATE |
+			   EXT4_GET_BLOCKS_METADATA_NOFAIL;
+	if (ext4_should_dioread_nolock(inode))
+		get_blocks_flags |= EXT4_GET_BLOCKS_IO_CREATE_EXT;
+	if (map->m_flags & (1 << BH_Delay))
+		get_blocks_flags |= EXT4_GET_BLOCKS_DELALLOC_RESERVE;
 
-	return ext4_chunk_trans_blocks(inode, max_blocks);
+	err = ext4_map_blocks(handle, inode, map, get_blocks_flags);
+	if (err < 0)
+		return err;
+	if (map->m_flags & EXT4_MAP_UNINIT) {
+		if (!mpd->io_submit.io_end->handle &&
+		    ext4_handle_valid(handle)) {
+			mpd->io_submit.io_end->handle = handle->h_rsv_handle;
+			handle->h_rsv_handle = NULL;
+		}
+		ext4_set_io_unwritten_flag(inode, mpd->io_submit.io_end);
+	}
+
+	BUG_ON(map->m_len == 0);
+	if (map->m_flags & EXT4_MAP_NEW) {
+		struct block_device *bdev = inode->i_sb->s_bdev;
+		int i;
+
+		for (i = 0; i < map->m_len; i++)
+			unmap_underlying_metadata(bdev, map->m_pblk + i);
+	}
+	return 0;
 }
 
 /*
- * write_cache_pages_da - walk the list of dirty pages of the given
- * address space and accumulate pages that need writing, and call
- * mpage_da_map_and_submit to map a single contiguous memory region
- * and then write them.
+ * mpage_map_and_submit_extent - map extent starting at mpd->lblk of length
+ *				 mpd->len and submit pages underlying it for IO
+ *
+ * @handle - handle for journal operations
+ * @mpd - extent to map
+ *
+ * The function maps extent starting at mpd->lblk of length mpd->len. If it is
+ * delayed, blocks are allocated, if it is unwritten, we may need to convert
+ * them to initialized or split the described range from larger unwritten
+ * extent. Note that we need not map all the described range since allocation
+ * can return less blocks or the range is covered by more unwritten extents. We
+ * cannot map more because we are limited by reserved transaction credits. On
+ * the other hand we always make sure that the last touched page is fully
+ * mapped so that it can be written out (and thus forward progress is
+ * guaranteed). After mapping we submit all mapped pages for IO.
  */
-static int write_cache_pages_da(handle_t *handle,
-				struct address_space *mapping,
-				struct writeback_control *wbc,
-				struct mpage_da_data *mpd,
-				pgoff_t *done_index)
+static int mpage_map_and_submit_extent(handle_t *handle,
+				       struct mpage_da_data *mpd,
+				       bool *give_up_on_write)
 {
-	struct buffer_head	*bh, *head;
-	struct inode		*inode = mapping->host;
-	struct pagevec		pvec;
-	unsigned int		nr_pages;
-	sector_t		logical;
-	pgoff_t			index, end;
-	long			nr_to_write = wbc->nr_to_write;
-	int			i, tag, ret = 0;
-
-	memset(mpd, 0, sizeof(struct mpage_da_data));
-	mpd->wbc = wbc;
-	mpd->inode = inode;
-	pagevec_init(&pvec, 0);
-	index = wbc->range_start >> PAGE_CACHE_SHIFT;
-	end = wbc->range_end >> PAGE_CACHE_SHIFT;
+	struct inode *inode = mpd->inode;
+	struct ext4_map_blocks *map = &mpd->map;
+	int err;
+	loff_t disksize;
 
-	if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
+	mpd->io_submit.io_end->offset =
+				((loff_t)map->m_lblk) << inode->i_blkbits;
+	while (map->m_len) {
+		err = mpage_map_one_extent(handle, mpd);
+		if (err < 0) {
+			struct super_block *sb = inode->i_sb;
+
+			if (EXT4_SB(sb)->s_mount_flags & EXT4_MF_FS_ABORTED)
+				goto invalidate_dirty_pages;
+			/*
+			 * Let the uper layers retry transient errors.
+			 * In the case of ENOSPC, if ext4_count_free_blocks()
+			 * is non-zero, a commit should free up blocks.
+			 */
+			if ((err == -ENOMEM) ||
+			    (err == -ENOSPC && ext4_count_free_clusters(sb)))
+				return err;
+			ext4_msg(sb, KERN_CRIT,
+				 "Delayed block allocation failed for "
+				 "inode %lu at logical offset %llu with"
+				 " max blocks %u with error %d",
+				 inode->i_ino,
+				 (unsigned long long)map->m_lblk,
+				 (unsigned)map->m_len, -err);
+			ext4_msg(sb, KERN_CRIT,
+				 "This should not happen!! Data will "
+				 "be lost\n");
+			if (err == -ENOSPC)
+				ext4_print_free_blocks(inode);
+		invalidate_dirty_pages:
+			*give_up_on_write = true;
+			return err;
+		}
+		/*
+		 * Update buffer state, submit mapped pages, and get us new
+		 * extent to map
+		 */
+		err = mpage_map_and_submit_buffers(mpd);
+		if (err < 0)
+			return err;
+	}
+
+	/* Update on-disk size after IO is submitted */
+	disksize = ((loff_t)mpd->first_page) << PAGE_CACHE_SHIFT;
+	if (disksize > i_size_read(inode))
+		disksize = i_size_read(inode);
+	if (disksize > EXT4_I(inode)->i_disksize) {
+		int err2;
+
+		ext4_update_i_disksize(inode, disksize);
+		err2 = ext4_mark_inode_dirty(handle, inode);
+		if (err2)
+			ext4_error(inode->i_sb,
+				   "Failed to mark inode %lu dirty",
+				   inode->i_ino);
+		if (!err)
+			err = err2;
+	}
+	return err;
+}
+
+/*
+ * Calculate the total number of credits to reserve for one writepages
+ * iteration. This is called from ext4_writepages(). We map an extent of
+ * upto MAX_WRITEPAGES_EXTENT_LEN blocks and then we go on and finish mapping
+ * the last partial page. So in total we can map MAX_WRITEPAGES_EXTENT_LEN +
+ * bpp - 1 blocks in bpp different extents.
+ */
+static int ext4_da_writepages_trans_blocks(struct inode *inode)
+{
+	int bpp = ext4_journal_blocks_per_page(inode);
+
+	return ext4_meta_trans_blocks(inode,
+				MAX_WRITEPAGES_EXTENT_LEN + bpp - 1, bpp);
+}
+
+/*
+ * mpage_prepare_extent_to_map - find & lock contiguous range of dirty pages
+ * 				 and underlying extent to map
+ *
+ * @mpd - where to look for pages
+ *
+ * Walk dirty pages in the mapping. If they are fully mapped, submit them for
+ * IO immediately. When we find a page which isn't mapped we start accumulating
+ * extent of buffers underlying these pages that needs mapping (formed by
+ * either delayed or unwritten buffers). We also lock the pages containing
+ * these buffers. The extent found is returned in @mpd structure (starting at
+ * mpd->lblk with length mpd->len blocks).
+ *
+ * Note that this function can attach bios to one io_end structure which are
+ * neither logically nor physically contiguous. Although it may seem as an
+ * unnecessary complication, it is actually inevitable in blocksize < pagesize
+ * case as we need to track IO to all buffers underlying a page in one io_end.
+ */
+static int mpage_prepare_extent_to_map(struct mpage_da_data *mpd)
+{
+	struct address_space *mapping = mpd->inode->i_mapping;
+	struct pagevec pvec;
+	unsigned int nr_pages;
+	pgoff_t index = mpd->first_page;
+	pgoff_t end = mpd->last_page;
+	int tag;
+	int i, err = 0;
+	int blkbits = mpd->inode->i_blkbits;
+	ext4_lblk_t lblk;
+	struct buffer_head *head;
+
+	if (mpd->wbc->sync_mode == WB_SYNC_ALL || mpd->wbc->tagged_writepages)
 		tag = PAGECACHE_TAG_TOWRITE;
 	else
 		tag = PAGECACHE_TAG_DIRTY;
 
-	*done_index = index;
+	pagevec_init(&pvec, 0);
+	mpd->map.m_len = 0;
+	mpd->next_page = index;
 	while (index <= end) {
 		nr_pages = pagevec_lookup_tag(&pvec, mapping, &index, tag,
 			      min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1);
 		if (nr_pages == 0)
-			return 0;
+			goto out;
 
 		for (i = 0; i < nr_pages; i++) {
 			struct page *page = pvec.pages[i];
@@ -2318,31 +2295,21 @@ static int write_cache_pages_da(handle_t *handle,
 			if (page->index > end)
 				goto out;
 
-			*done_index = page->index + 1;
-
-			/*
-			 * If we can't merge this page, and we have
-			 * accumulated an contiguous region, write it
-			 */
-			if ((mpd->next_page != page->index) &&
-			    (mpd->next_page != mpd->first_page)) {
-				mpage_da_map_and_submit(mpd);
-				goto ret_extent_tail;
-			}
+			/* If we can't merge this page, we are done. */
+			if (mpd->map.m_len > 0 && mpd->next_page != page->index)
+				goto out;
 
 			lock_page(page);
-
 			/*
-			 * If the page is no longer dirty, or its
-			 * mapping no longer corresponds to inode we
-			 * are writing (which means it has been
-			 * truncated or invalidated), or the page is
-			 * already under writeback and we are not
-			 * doing a data integrity writeback, skip the page
+			 * If the page is no longer dirty, or its mapping no
+			 * longer corresponds to inode we are writing (which
+			 * means it has been truncated or invalidated), or the
+			 * page is already under writeback and we are not doing
+			 * a data integrity writeback, skip the page
 			 */
 			if (!PageDirty(page) ||
 			    (PageWriteback(page) &&
-			     (wbc->sync_mode == WB_SYNC_NONE)) ||
+			     (mpd->wbc->sync_mode == WB_SYNC_NONE)) ||
 			    unlikely(page->mapping != mapping)) {
 				unlock_page(page);
 				continue;
@@ -2351,106 +2318,70 @@ static int write_cache_pages_da(handle_t *handle,
 			wait_on_page_writeback(page);
 			BUG_ON(PageWriteback(page));
 
-			/*
-			 * If we have inline data and arrive here, it means that
-			 * we will soon create the block for the 1st page, so
-			 * we'd better clear the inline data here.
-			 */
-			if (ext4_has_inline_data(inode)) {
-				BUG_ON(ext4_test_inode_state(inode,
-						EXT4_STATE_MAY_INLINE_DATA));
-				ext4_destroy_inline_data(handle, inode);
-			}
-
-			if (mpd->next_page != page->index)
+			if (mpd->map.m_len == 0)
 				mpd->first_page = page->index;
 			mpd->next_page = page->index + 1;
-			logical = (sector_t) page->index <<
-				(PAGE_CACHE_SHIFT - inode->i_blkbits);
-
 			/* Add all dirty buffers to mpd */
+			lblk = ((ext4_lblk_t)page->index) <<
+				(PAGE_CACHE_SHIFT - blkbits);
 			head = page_buffers(page);
-			bh = head;
-			do {
-				BUG_ON(buffer_locked(bh));
-				/*
-				 * We need to try to allocate unmapped blocks
-				 * in the same page.  Otherwise we won't make
-				 * progress with the page in ext4_writepage
-				 */
-				if (ext4_bh_delay_or_unwritten(NULL, bh)) {
-					mpage_add_bh_to_extent(mpd, logical,
-							       bh->b_state);
-					if (mpd->io_done)
-						goto ret_extent_tail;
-				} else if (buffer_dirty(bh) &&
-					   buffer_mapped(bh)) {
-					/*
-					 * mapped dirty buffer. We need to
-					 * update the b_state because we look
-					 * at b_state in mpage_da_map_blocks.
-					 * We don't update b_size because if we
-					 * find an unmapped buffer_head later
-					 * we need to use the b_state flag of
-					 * that buffer_head.
-					 */
-					if (mpd->b_size == 0)
-						mpd->b_state =
-							bh->b_state & BH_FLAGS;
-				}
-				logical++;
-			} while ((bh = bh->b_this_page) != head);
-
-			if (nr_to_write > 0) {
-				nr_to_write--;
-				if (nr_to_write == 0 &&
-				    wbc->sync_mode == WB_SYNC_NONE)
-					/*
-					 * We stop writing back only if we are
-					 * not doing integrity sync. In case of
-					 * integrity sync we have to keep going
-					 * because someone may be concurrently
-					 * dirtying pages, and we might have
-					 * synced a lot of newly appeared dirty
-					 * pages, but have not synced all of the
-					 * old dirty pages.
-					 */
+			if (!add_page_bufs_to_extent(mpd, head, head, lblk))
+				goto out;
+			/* So far everything mapped? Submit the page for IO. */
+			if (mpd->map.m_len == 0) {
+				err = mpage_submit_page(mpd, page);
+				if (err < 0)
 					goto out;
 			}
+
+			/*
+			 * Accumulated enough dirty pages? This doesn't apply
+			 * to WB_SYNC_ALL mode. For integrity sync we have to
+			 * keep going because someone may be concurrently
+			 * dirtying pages, and we might have synced a lot of
+			 * newly appeared dirty pages, but have not synced all
+			 * of the old dirty pages.
+			 */
+			if (mpd->wbc->sync_mode == WB_SYNC_NONE &&
+			    mpd->next_page - mpd->first_page >=
+							mpd->wbc->nr_to_write)
+				goto out;
 		}
 		pagevec_release(&pvec);
 		cond_resched();
 	}
 	return 0;
-ret_extent_tail:
-	ret = MPAGE_DA_EXTENT_TAIL;
 out:
 	pagevec_release(&pvec);
-	cond_resched();
-	return ret;
+	return err;
 }
 
+static int __writepage(struct page *page, struct writeback_control *wbc,
+		       void *data)
+{
+	struct address_space *mapping = data;
+	int ret = ext4_writepage(page, wbc);
+	mapping_set_error(mapping, ret);
+	return ret;
+}
 
-static int ext4_da_writepages(struct address_space *mapping,
-			      struct writeback_control *wbc)
+static int ext4_writepages(struct address_space *mapping,
+			   struct writeback_control *wbc)
 {
-	pgoff_t	index;
+	pgoff_t	writeback_index = 0;
+	long nr_to_write = wbc->nr_to_write;
 	int range_whole = 0;
+	int cycled = 1;
 	handle_t *handle = NULL;
 	struct mpage_da_data mpd;
 	struct inode *inode = mapping->host;
-	int pages_written = 0;
-	unsigned int max_pages;
-	int range_cyclic, cycled = 1, io_done = 0;
-	int needed_blocks, ret = 0;
-	long desired_nr_to_write, nr_to_writebump = 0;
-	loff_t range_start = wbc->range_start;
+	int needed_blocks, rsv_blocks = 0, ret = 0;
 	struct ext4_sb_info *sbi = EXT4_SB(mapping->host->i_sb);
-	pgoff_t done_index = 0;
-	pgoff_t end;
+	bool done;
 	struct blk_plug plug;
+	bool give_up_on_write = false;
 
-	trace_ext4_da_writepages(inode, wbc);
+	trace_ext4_writepages(inode, wbc);
 
 	/*
 	 * No pages to write? This is mainly a kludge to avoid starting
@@ -2460,164 +2391,165 @@ static int ext4_da_writepages(struct address_space *mapping,
 	if (!mapping->nrpages || !mapping_tagged(mapping, PAGECACHE_TAG_DIRTY))
 		return 0;
 
+	if (ext4_should_journal_data(inode)) {
+		struct blk_plug plug;
+		int ret;
+
+		blk_start_plug(&plug);
+		ret = write_cache_pages(mapping, wbc, __writepage, mapping);
+		blk_finish_plug(&plug);
+		return ret;
+	}
+
 	/*
 	 * If the filesystem has aborted, it is read-only, so return
 	 * right away instead of dumping stack traces later on that
 	 * will obscure the real source of the problem.  We test
 	 * EXT4_MF_FS_ABORTED instead of sb->s_flag's MS_RDONLY because
 	 * the latter could be true if the filesystem is mounted
-	 * read-only, and in that case, ext4_da_writepages should
+	 * read-only, and in that case, ext4_writepages should
 	 * *never* be called, so if that ever happens, we would want
 	 * the stack trace.
 	 */
 	if (unlikely(sbi->s_mount_flags & EXT4_MF_FS_ABORTED))
 		return -EROFS;
 
+	if (ext4_should_dioread_nolock(inode)) {
+		/*
+		 * We may need to convert upto one extent per block in
+		 * the page and we may dirty the inode.
+		 */
+		rsv_blocks = 1 + (PAGE_CACHE_SIZE >> inode->i_blkbits);
+	}
+
+	/*
+	 * If we have inline data and arrive here, it means that
+	 * we will soon create the block for the 1st page, so
+	 * we'd better clear the inline data here.
+	 */
+	if (ext4_has_inline_data(inode)) {
+		/* Just inode will be modified... */
+		handle = ext4_journal_start(inode, EXT4_HT_INODE, 1);
+		if (IS_ERR(handle)) {
+			ret = PTR_ERR(handle);
+			goto out_writepages;
+		}
+		BUG_ON(ext4_test_inode_state(inode,
+				EXT4_STATE_MAY_INLINE_DATA));
+		ext4_destroy_inline_data(handle, inode);
+		ext4_journal_stop(handle);
+	}
+
 	if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
 		range_whole = 1;
 
-	range_cyclic = wbc->range_cyclic;
 	if (wbc->range_cyclic) {
-		index = mapping->writeback_index;
-		if (index)
+		writeback_index = mapping->writeback_index;
+		if (writeback_index)
 			cycled = 0;
-		wbc->range_start = index << PAGE_CACHE_SHIFT;
-		wbc->range_end  = LLONG_MAX;
-		wbc->range_cyclic = 0;
-		end = -1;
+		mpd.first_page = writeback_index;
+		mpd.last_page = -1;
 	} else {
-		index = wbc->range_start >> PAGE_CACHE_SHIFT;
-		end = wbc->range_end >> PAGE_CACHE_SHIFT;
-	}
-
-	/*
-	 * This works around two forms of stupidity.  The first is in
-	 * the writeback code, which caps the maximum number of pages
-	 * written to be 1024 pages.  This is wrong on multiple
-	 * levels; different architectues have a different page size,
-	 * which changes the maximum amount of data which gets
-	 * written.  Secondly, 4 megabytes is way too small.  XFS
-	 * forces this value to be 16 megabytes by multiplying
-	 * nr_to_write parameter by four, and then relies on its
-	 * allocator to allocate larger extents to make them
-	 * contiguous.  Unfortunately this brings us to the second
-	 * stupidity, which is that ext4's mballoc code only allocates
-	 * at most 2048 blocks.  So we force contiguous writes up to
-	 * the number of dirty blocks in the inode, or
-	 * sbi->max_writeback_mb_bump whichever is smaller.
-	 */
-	max_pages = sbi->s_max_writeback_mb_bump << (20 - PAGE_CACHE_SHIFT);
-	if (!range_cyclic && range_whole) {
-		if (wbc->nr_to_write == LONG_MAX)
-			desired_nr_to_write = wbc->nr_to_write;
-		else
-			desired_nr_to_write = wbc->nr_to_write * 8;
-	} else
-		desired_nr_to_write = ext4_num_dirty_pages(inode, index,
-							   max_pages);
-	if (desired_nr_to_write > max_pages)
-		desired_nr_to_write = max_pages;
-
-	if (wbc->nr_to_write < desired_nr_to_write) {
-		nr_to_writebump = desired_nr_to_write - wbc->nr_to_write;
-		wbc->nr_to_write = desired_nr_to_write;
+		mpd.first_page = wbc->range_start >> PAGE_CACHE_SHIFT;
+		mpd.last_page = wbc->range_end >> PAGE_CACHE_SHIFT;
 	}
 
+	mpd.inode = inode;
+	mpd.wbc = wbc;
+	ext4_io_submit_init(&mpd.io_submit, wbc);
 retry:
 	if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
-		tag_pages_for_writeback(mapping, index, end);
-
+		tag_pages_for_writeback(mapping, mpd.first_page, mpd.last_page);
+	done = false;
 	blk_start_plug(&plug);
-	while (!ret && wbc->nr_to_write > 0) {
+	while (!done && mpd.first_page <= mpd.last_page) {
+		/* For each extent of pages we use new io_end */
+		mpd.io_submit.io_end = ext4_init_io_end(inode, GFP_KERNEL);
+		if (!mpd.io_submit.io_end) {
+			ret = -ENOMEM;
+			break;
+		}
 
 		/*
-		 * we  insert one extent at a time. So we need
-		 * credit needed for single extent allocation.
-		 * journalled mode is currently not supported
-		 * by delalloc
+		 * We have two constraints: We find one extent to map and we
+		 * must always write out whole page (makes a difference when
+		 * blocksize < pagesize) so that we don't block on IO when we
+		 * try to write out the rest of the page. Journalled mode is
+		 * not supported by delalloc.
 		 */
 		BUG_ON(ext4_should_journal_data(inode));
 		needed_blocks = ext4_da_writepages_trans_blocks(inode);
 
-		/* start a new transaction*/
-		handle = ext4_journal_start(inode, EXT4_HT_WRITE_PAGE,
-					    needed_blocks);
+		/* start a new transaction */
+		handle = ext4_journal_start_with_reserve(inode,
+				EXT4_HT_WRITE_PAGE, needed_blocks, rsv_blocks);
 		if (IS_ERR(handle)) {
 			ret = PTR_ERR(handle);
 			ext4_msg(inode->i_sb, KERN_CRIT, "%s: jbd2_start: "
 			       "%ld pages, ino %lu; err %d", __func__,
 				wbc->nr_to_write, inode->i_ino, ret);
-			blk_finish_plug(&plug);
-			goto out_writepages;
+			/* Release allocated io_end */
+			ext4_put_io_end(mpd.io_submit.io_end);
+			break;
 		}
 
-		/*
-		 * Now call write_cache_pages_da() to find the next
-		 * contiguous region of logical blocks that need
-		 * blocks to be allocated by ext4 and submit them.
-		 */
-		ret = write_cache_pages_da(handle, mapping,
-					   wbc, &mpd, &done_index);
-		/*
-		 * If we have a contiguous extent of pages and we
-		 * haven't done the I/O yet, map the blocks and submit
-		 * them for I/O.
-		 */
-		if (!mpd.io_done && mpd.next_page != mpd.first_page) {
-			mpage_da_map_and_submit(&mpd);
-			ret = MPAGE_DA_EXTENT_TAIL;
+		trace_ext4_da_write_pages(inode, mpd.first_page, mpd.wbc);
+		ret = mpage_prepare_extent_to_map(&mpd);
+		if (!ret) {
+			if (mpd.map.m_len)
+				ret = mpage_map_and_submit_extent(handle, &mpd,
+					&give_up_on_write);
+			else {
+				/*
+				 * We scanned the whole range (or exhausted
+				 * nr_to_write), submitted what was mapped and
+				 * didn't find anything needing mapping. We are
+				 * done.
+				 */
+				done = true;
+			}
 		}
-		trace_ext4_da_write_pages(inode, &mpd);
-		wbc->nr_to_write -= mpd.pages_written;
-
 		ext4_journal_stop(handle);
-
-		if ((mpd.retval == -ENOSPC) && sbi->s_journal) {
-			/* commit the transaction which would
+		/* Submit prepared bio */
+		ext4_io_submit(&mpd.io_submit);
+		/* Unlock pages we didn't use */
+		mpage_release_unused_pages(&mpd, give_up_on_write);
+		/* Drop our io_end reference we got from init */
+		ext4_put_io_end(mpd.io_submit.io_end);
+
+		if (ret == -ENOSPC && sbi->s_journal) {
+			/*
+			 * Commit the transaction which would
 			 * free blocks released in the transaction
 			 * and try again
 			 */
 			jbd2_journal_force_commit_nested(sbi->s_journal);
 			ret = 0;
-		} else if (ret == MPAGE_DA_EXTENT_TAIL) {
-			/*
-			 * Got one extent now try with rest of the pages.
-			 * If mpd.retval is set -EIO, journal is aborted.
-			 * So we don't need to write any more.
-			 */
-			pages_written += mpd.pages_written;
-			ret = mpd.retval;
-			io_done = 1;
-		} else if (wbc->nr_to_write)
-			/*
-			 * There is no more writeout needed
-			 * or we requested for a noblocking writeout
-			 * and we found the device congested
-			 */
+			continue;
+		}
+		/* Fatal error - ENOMEM, EIO... */
+		if (ret)
 			break;
 	}
 	blk_finish_plug(&plug);
-	if (!io_done && !cycled) {
+	if (!ret && !cycled) {
 		cycled = 1;
-		index = 0;
-		wbc->range_start = index << PAGE_CACHE_SHIFT;
-		wbc->range_end  = mapping->writeback_index - 1;
+		mpd.last_page = writeback_index - 1;
+		mpd.first_page = 0;
 		goto retry;
 	}
 
 	/* Update index */
-	wbc->range_cyclic = range_cyclic;
 	if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
 		/*
-		 * set the writeback_index so that range_cyclic
+		 * Set the writeback_index so that range_cyclic
 		 * mode will write it back later
 		 */
-		mapping->writeback_index = done_index;
+		mapping->writeback_index = mpd.first_page;
 
 out_writepages:
-	wbc->nr_to_write -= nr_to_writebump;
-	wbc->range_start = range_start;
-	trace_ext4_da_writepages_result(inode, wbc, ret, pages_written);
+	trace_ext4_writepages_result(inode, wbc, ret,
+				     nr_to_write - wbc->nr_to_write);
 	return ret;
 }
 
@@ -2829,7 +2761,8 @@ static int ext4_da_write_end(struct file *file,
 	return ret ? ret : copied;
 }
 
-static void ext4_da_invalidatepage(struct page *page, unsigned long offset)
+static void ext4_da_invalidatepage(struct page *page, unsigned int offset,
+				   unsigned int length)
 {
 	/*
 	 * Drop reserved blocks
@@ -2838,10 +2771,10 @@ static void ext4_da_invalidatepage(struct page *page, unsigned long offset)
 	if (!page_has_buffers(page))
 		goto out;
 
-	ext4_da_page_release_reservation(page, offset);
+	ext4_da_page_release_reservation(page, offset, length);
 
 out:
-	ext4_invalidatepage(page, offset);
+	ext4_invalidatepage(page, offset, length);
 
 	return;
 }
@@ -2864,7 +2797,7 @@ int ext4_alloc_da_blocks(struct inode *inode)
 	 * laptop_mode, not even desirable).  However, to do otherwise
 	 * would require replicating code paths in:
 	 *
-	 * ext4_da_writepages() ->
+	 * ext4_writepages() ->
 	 *    write_cache_pages() ---> (via passed in callback function)
 	 *        __mpage_da_writepage() -->
 	 *           mpage_add_bh_to_extent()
@@ -2989,37 +2922,40 @@ ext4_readpages(struct file *file, struct address_space *mapping,
 	return mpage_readpages(mapping, pages, nr_pages, ext4_get_block);
 }
 
-static void ext4_invalidatepage(struct page *page, unsigned long offset)
+static void ext4_invalidatepage(struct page *page, unsigned int offset,
+				unsigned int length)
 {
-	trace_ext4_invalidatepage(page, offset);
+	trace_ext4_invalidatepage(page, offset, length);
 
 	/* No journalling happens on data buffers when this function is used */
 	WARN_ON(page_has_buffers(page) && buffer_jbd(page_buffers(page)));
 
-	block_invalidatepage(page, offset);
+	block_invalidatepage(page, offset, length);
 }
 
 static int __ext4_journalled_invalidatepage(struct page *page,
-					    unsigned long offset)
+					    unsigned int offset,
+					    unsigned int length)
 {
 	journal_t *journal = EXT4_JOURNAL(page->mapping->host);
 
-	trace_ext4_journalled_invalidatepage(page, offset);
+	trace_ext4_journalled_invalidatepage(page, offset, length);
 
 	/*
 	 * If it's a full truncate we just forget about the pending dirtying
 	 */
-	if (offset == 0)
+	if (offset == 0 && length == PAGE_CACHE_SIZE)
 		ClearPageChecked(page);
 
-	return jbd2_journal_invalidatepage(journal, page, offset);
+	return jbd2_journal_invalidatepage(journal, page, offset, length);
 }
 
 /* Wrapper for aops... */
 static void ext4_journalled_invalidatepage(struct page *page,
-					   unsigned long offset)
+					   unsigned int offset,
+					   unsigned int length)
 {
-	WARN_ON(__ext4_journalled_invalidatepage(page, offset) < 0);
+	WARN_ON(__ext4_journalled_invalidatepage(page, offset, length) < 0);
 }
 
 static int ext4_releasepage(struct page *page, gfp_t wait)
@@ -3067,9 +3003,13 @@ static void ext4_end_io_dio(struct kiocb *iocb, loff_t offset,
 	struct inode *inode = file_inode(iocb->ki_filp);
         ext4_io_end_t *io_end = iocb->private;
 
-	/* if not async direct IO or dio with 0 bytes write, just return */
-	if (!io_end || !size)
-		goto out;
+	/* if not async direct IO just return */
+	if (!io_end) {
+		inode_dio_done(inode);
+		if (is_async)
+			aio_complete(iocb, ret, 0);
+		return;
+	}
 
 	ext_debug("ext4_end_io_dio(): io_end 0x%p "
 		  "for inode %lu, iocb 0x%p, offset %llu, size %zd\n",
@@ -3077,25 +3017,13 @@ static void ext4_end_io_dio(struct kiocb *iocb, loff_t offset,
 		  size);
 
 	iocb->private = NULL;
-
-	/* if not aio dio with unwritten extents, just free io and return */
-	if (!(io_end->flag & EXT4_IO_END_UNWRITTEN)) {
-		ext4_free_io_end(io_end);
-out:
-		inode_dio_done(inode);
-		if (is_async)
-			aio_complete(iocb, ret, 0);
-		return;
-	}
-
 	io_end->offset = offset;
 	io_end->size = size;
 	if (is_async) {
 		io_end->iocb = iocb;
 		io_end->result = ret;
 	}
-
-	ext4_add_complete_io(io_end);
+	ext4_put_io_end_defer(io_end);
 }
 
 /*
@@ -3129,6 +3057,7 @@ static ssize_t ext4_ext_direct_IO(int rw, struct kiocb *iocb,
 	get_block_t *get_block_func = NULL;
 	int dio_flags = 0;
 	loff_t final_size = offset + count;
+	ext4_io_end_t *io_end = NULL;
 
 	/* Use the old path for reads and writes beyond i_size. */
 	if (rw != WRITE || final_size > inode->i_size)
@@ -3136,11 +3065,18 @@ static ssize_t ext4_ext_direct_IO(int rw, struct kiocb *iocb,
 
 	BUG_ON(iocb->private == NULL);
 
+	/*
+	 * Make all waiters for direct IO properly wait also for extent
+	 * conversion. This also disallows race between truncate() and
+	 * overwrite DIO as i_dio_count needs to be incremented under i_mutex.
+	 */
+	if (rw == WRITE)
+		atomic_inc(&inode->i_dio_count);
+
 	/* If we do a overwrite dio, i_mutex locking can be released */
 	overwrite = *((int *)iocb->private);
 
 	if (overwrite) {
-		atomic_inc(&inode->i_dio_count);
 		down_read(&EXT4_I(inode)->i_data_sem);
 		mutex_unlock(&inode->i_mutex);
 	}
@@ -3167,13 +3103,16 @@ static ssize_t ext4_ext_direct_IO(int rw, struct kiocb *iocb,
 	iocb->private = NULL;
 	ext4_inode_aio_set(inode, NULL);
 	if (!is_sync_kiocb(iocb)) {
-		ext4_io_end_t *io_end = ext4_init_io_end(inode, GFP_NOFS);
+		io_end = ext4_init_io_end(inode, GFP_NOFS);
 		if (!io_end) {
 			ret = -ENOMEM;
 			goto retake_lock;
 		}
 		io_end->flag |= EXT4_IO_END_DIRECT;
-		iocb->private = io_end;
+		/*
+		 * Grab reference for DIO. Will be dropped in ext4_end_io_dio()
+		 */
+		iocb->private = ext4_get_io_end(io_end);
 		/*
 		 * we save the io structure for current async direct
 		 * IO, so that later ext4_map_blocks() could flag the
@@ -3197,33 +3136,42 @@ static ssize_t ext4_ext_direct_IO(int rw, struct kiocb *iocb,
 				   NULL,
 				   dio_flags);
 
-	if (iocb->private)
-		ext4_inode_aio_set(inode, NULL);
 	/*
-	 * The io_end structure takes a reference to the inode, that
-	 * structure needs to be destroyed and the reference to the
-	 * inode need to be dropped, when IO is complete, even with 0
-	 * byte write, or failed.
-	 *
-	 * In the successful AIO DIO case, the io_end structure will
-	 * be destroyed and the reference to the inode will be dropped
-	 * after the end_io call back function is called.
-	 *
-	 * In the case there is 0 byte write, or error case, since VFS
-	 * direct IO won't invoke the end_io call back function, we
-	 * need to free the end_io structure here.
+	 * Put our reference to io_end. This can free the io_end structure e.g.
+	 * in sync IO case or in case of error. It can even perform extent
+	 * conversion if all bios we submitted finished before we got here.
+	 * Note that in that case iocb->private can be already set to NULL
+	 * here.
 	 */
-	if (ret != -EIOCBQUEUED && ret <= 0 && iocb->private) {
-		ext4_free_io_end(iocb->private);
-		iocb->private = NULL;
-	} else if (ret > 0 && !overwrite && ext4_test_inode_state(inode,
+	if (io_end) {
+		ext4_inode_aio_set(inode, NULL);
+		ext4_put_io_end(io_end);
+		/*
+		 * When no IO was submitted ext4_end_io_dio() was not
+		 * called so we have to put iocb's reference.
+		 */
+		if (ret <= 0 && ret != -EIOCBQUEUED && iocb->private) {
+			WARN_ON(iocb->private != io_end);
+			WARN_ON(io_end->flag & EXT4_IO_END_UNWRITTEN);
+			WARN_ON(io_end->iocb);
+			/*
+			 * Generic code already did inode_dio_done() so we
+			 * have to clear EXT4_IO_END_DIRECT to not do it for
+			 * the second time.
+			 */
+			io_end->flag = 0;
+			ext4_put_io_end(io_end);
+			iocb->private = NULL;
+		}
+	}
+	if (ret > 0 && !overwrite && ext4_test_inode_state(inode,
 						EXT4_STATE_DIO_UNWRITTEN)) {
 		int err;
 		/*
 		 * for non AIO case, since the IO is already
 		 * completed, we could do the conversion right here
 		 */
-		err = ext4_convert_unwritten_extents(inode,
+		err = ext4_convert_unwritten_extents(NULL, inode,
 						     offset, ret);
 		if (err < 0)
 			ret = err;
@@ -3231,9 +3179,10 @@ static ssize_t ext4_ext_direct_IO(int rw, struct kiocb *iocb,
 	}
 
 retake_lock:
+	if (rw == WRITE)
+		inode_dio_done(inode);
 	/* take i_mutex locking again if we do a ovewrite dio */
 	if (overwrite) {
-		inode_dio_done(inode);
 		up_read(&EXT4_I(inode)->i_data_sem);
 		mutex_lock(&inode->i_mutex);
 	}
@@ -3292,6 +3241,7 @@ static const struct address_space_operations ext4_aops = {
 	.readpage		= ext4_readpage,
 	.readpages		= ext4_readpages,
 	.writepage		= ext4_writepage,
+	.writepages		= ext4_writepages,
 	.write_begin		= ext4_write_begin,
 	.write_end		= ext4_write_end,
 	.bmap			= ext4_bmap,
@@ -3307,6 +3257,7 @@ static const struct address_space_operations ext4_journalled_aops = {
 	.readpage		= ext4_readpage,
 	.readpages		= ext4_readpages,
 	.writepage		= ext4_writepage,
+	.writepages		= ext4_writepages,
 	.write_begin		= ext4_write_begin,
 	.write_end		= ext4_journalled_write_end,
 	.set_page_dirty		= ext4_journalled_set_page_dirty,
@@ -3322,7 +3273,7 @@ static const struct address_space_operations ext4_da_aops = {
 	.readpage		= ext4_readpage,
 	.readpages		= ext4_readpages,
 	.writepage		= ext4_writepage,
-	.writepages		= ext4_da_writepages,
+	.writepages		= ext4_writepages,
 	.write_begin		= ext4_da_write_begin,
 	.write_end		= ext4_da_write_end,
 	.bmap			= ext4_bmap,
@@ -3355,89 +3306,56 @@ void ext4_set_aops(struct inode *inode)
 		inode->i_mapping->a_ops = &ext4_aops;
 }
 
-
 /*
- * ext4_discard_partial_page_buffers()
- * Wrapper function for ext4_discard_partial_page_buffers_no_lock.
- * This function finds and locks the page containing the offset
- * "from" and passes it to ext4_discard_partial_page_buffers_no_lock.
- * Calling functions that already have the page locked should call
- * ext4_discard_partial_page_buffers_no_lock directly.
+ * ext4_block_truncate_page() zeroes out a mapping from file offset `from'
+ * up to the end of the block which corresponds to `from'.
+ * This required during truncate. We need to physically zero the tail end
+ * of that block so it doesn't yield old data if the file is later grown.
  */
-int ext4_discard_partial_page_buffers(handle_t *handle,
-		struct address_space *mapping, loff_t from,
-		loff_t length, int flags)
+int ext4_block_truncate_page(handle_t *handle,
+		struct address_space *mapping, loff_t from)
 {
+	unsigned offset = from & (PAGE_CACHE_SIZE-1);
+	unsigned length;
+	unsigned blocksize;
 	struct inode *inode = mapping->host;
-	struct page *page;
-	int err = 0;
 
-	page = find_or_create_page(mapping, from >> PAGE_CACHE_SHIFT,
-				   mapping_gfp_mask(mapping) & ~__GFP_FS);
-	if (!page)
-		return -ENOMEM;
-
-	err = ext4_discard_partial_page_buffers_no_lock(handle, inode, page,
-		from, length, flags);
+	blocksize = inode->i_sb->s_blocksize;
+	length = blocksize - (offset & (blocksize - 1));
 
-	unlock_page(page);
-	page_cache_release(page);
-	return err;
+	return ext4_block_zero_page_range(handle, mapping, from, length);
 }
 
 /*
- * ext4_discard_partial_page_buffers_no_lock()
- * Zeros a page range of length 'length' starting from offset 'from'.
- * Buffer heads that correspond to the block aligned regions of the
- * zeroed range will be unmapped.  Unblock aligned regions
- * will have the corresponding buffer head mapped if needed so that
- * that region of the page can be updated with the partial zero out.
- *
- * This function assumes that the page has already been  locked.  The
- * The range to be discarded must be contained with in the given page.
- * If the specified range exceeds the end of the page it will be shortened
- * to the end of the page that corresponds to 'from'.  This function is
- * appropriate for updating a page and it buffer heads to be unmapped and
- * zeroed for blocks that have been either released, or are going to be
- * released.
- *
- * handle: The journal handle
- * inode:  The files inode
- * page:   A locked page that contains the offset "from"
- * from:   The starting byte offset (from the beginning of the file)
- *         to begin discarding
- * len:    The length of bytes to discard
- * flags:  Optional flags that may be used:
- *
- *         EXT4_DISCARD_PARTIAL_PG_ZERO_UNMAPPED
- *         Only zero the regions of the page whose buffer heads
- *         have already been unmapped.  This flag is appropriate
- *         for updating the contents of a page whose blocks may
- *         have already been released, and we only want to zero
- *         out the regions that correspond to those released blocks.
- *
- * Returns zero on success or negative on failure.
+ * ext4_block_zero_page_range() zeros out a mapping of length 'length'
+ * starting from file offset 'from'.  The range to be zero'd must
+ * be contained with in one block.  If the specified range exceeds
+ * the end of the block it will be shortened to end of the block
+ * that cooresponds to 'from'
  */
-static int ext4_discard_partial_page_buffers_no_lock(handle_t *handle,
-		struct inode *inode, struct page *page, loff_t from,
-		loff_t length, int flags)
+int ext4_block_zero_page_range(handle_t *handle,
+		struct address_space *mapping, loff_t from, loff_t length)
 {
 	ext4_fsblk_t index = from >> PAGE_CACHE_SHIFT;
-	unsigned int offset = from & (PAGE_CACHE_SIZE-1);
-	unsigned int blocksize, max, pos;
+	unsigned offset = from & (PAGE_CACHE_SIZE-1);
+	unsigned blocksize, max, pos;
 	ext4_lblk_t iblock;
+	struct inode *inode = mapping->host;
 	struct buffer_head *bh;
+	struct page *page;
 	int err = 0;
 
-	blocksize = inode->i_sb->s_blocksize;
-	max = PAGE_CACHE_SIZE - offset;
+	page = find_or_create_page(mapping, from >> PAGE_CACHE_SHIFT,
+				   mapping_gfp_mask(mapping) & ~__GFP_FS);
+	if (!page)
+		return -ENOMEM;
 
-	if (index != page->index)
-		return -EINVAL;
+	blocksize = inode->i_sb->s_blocksize;
+	max = blocksize - (offset & (blocksize - 1));
 
 	/*
 	 * correct length if it does not fall between
-	 * 'from' and the end of the page
+	 * 'from' and the end of the block
 	 */
 	if (length > max || length < 0)
 		length = max;
@@ -3455,106 +3373,91 @@ static int ext4_discard_partial_page_buffers_no_lock(handle_t *handle,
 		iblock++;
 		pos += blocksize;
 	}
-
-	pos = offset;
-	while (pos < offset + length) {
-		unsigned int end_of_block, range_to_discard;
-
-		err = 0;
-
-		/* The length of space left to zero and unmap */
-		range_to_discard = offset + length - pos;
-
-		/* The length of space until the end of the block */
-		end_of_block = blocksize - (pos & (blocksize-1));
-
-		/*
-		 * Do not unmap or zero past end of block
-		 * for this buffer head
-		 */
-		if (range_to_discard > end_of_block)
-			range_to_discard = end_of_block;
-
-
-		/*
-		 * Skip this buffer head if we are only zeroing unampped
-		 * regions of the page
-		 */
-		if (flags & EXT4_DISCARD_PARTIAL_PG_ZERO_UNMAPPED &&
-			buffer_mapped(bh))
-				goto next;
-
-		/* If the range is block aligned, unmap */
-		if (range_to_discard == blocksize) {
-			clear_buffer_dirty(bh);
-			bh->b_bdev = NULL;
-			clear_buffer_mapped(bh);
-			clear_buffer_req(bh);
-			clear_buffer_new(bh);
-			clear_buffer_delay(bh);
-			clear_buffer_unwritten(bh);
-			clear_buffer_uptodate(bh);
-			zero_user(page, pos, range_to_discard);
-			BUFFER_TRACE(bh, "Buffer discarded");
-			goto next;
-		}
-
-		/*
-		 * If this block is not completely contained in the range
-		 * to be discarded, then it is not going to be released. Because
-		 * we need to keep this block, we need to make sure this part
-		 * of the page is uptodate before we modify it by writeing
-		 * partial zeros on it.
-		 */
+	if (buffer_freed(bh)) {
+		BUFFER_TRACE(bh, "freed: skip");
+		goto unlock;
+	}
+	if (!buffer_mapped(bh)) {
+		BUFFER_TRACE(bh, "unmapped");
+		ext4_get_block(inode, iblock, bh, 0);
+		/* unmapped? It's a hole - nothing to do */
 		if (!buffer_mapped(bh)) {
-			/*
-			 * Buffer head must be mapped before we can read
-			 * from the block
-			 */
-			BUFFER_TRACE(bh, "unmapped");
-			ext4_get_block(inode, iblock, bh, 0);
-			/* unmapped? It's a hole - nothing to do */
-			if (!buffer_mapped(bh)) {
-				BUFFER_TRACE(bh, "still unmapped");
-				goto next;
-			}
+			BUFFER_TRACE(bh, "still unmapped");
+			goto unlock;
 		}
+	}
 
-		/* Ok, it's mapped. Make sure it's up-to-date */
-		if (PageUptodate(page))
-			set_buffer_uptodate(bh);
+	/* Ok, it's mapped. Make sure it's up-to-date */
+	if (PageUptodate(page))
+		set_buffer_uptodate(bh);
 
-		if (!buffer_uptodate(bh)) {
-			err = -EIO;
-			ll_rw_block(READ, 1, &bh);
-			wait_on_buffer(bh);
-			/* Uhhuh. Read error. Complain and punt.*/
-			if (!buffer_uptodate(bh))
-				goto next;
-		}
+	if (!buffer_uptodate(bh)) {
+		err = -EIO;
+		ll_rw_block(READ, 1, &bh);
+		wait_on_buffer(bh);
+		/* Uhhuh. Read error. Complain and punt. */
+		if (!buffer_uptodate(bh))
+			goto unlock;
+	}
+	if (ext4_should_journal_data(inode)) {
+		BUFFER_TRACE(bh, "get write access");
+		err = ext4_journal_get_write_access(handle, bh);
+		if (err)
+			goto unlock;
+	}
+	zero_user(page, offset, length);
+	BUFFER_TRACE(bh, "zeroed end of block");
 
-		if (ext4_should_journal_data(inode)) {
-			BUFFER_TRACE(bh, "get write access");
-			err = ext4_journal_get_write_access(handle, bh);
-			if (err)
-				goto next;
-		}
+	if (ext4_should_journal_data(inode)) {
+		err = ext4_handle_dirty_metadata(handle, inode, bh);
+	} else {
+		err = 0;
+		mark_buffer_dirty(bh);
+		if (ext4_test_inode_state(inode, EXT4_STATE_ORDERED_MODE))
+			err = ext4_jbd2_file_inode(handle, inode);
+	}
+
+unlock:
+	unlock_page(page);
+	page_cache_release(page);
+	return err;
+}
 
-		zero_user(page, pos, range_to_discard);
+int ext4_zero_partial_blocks(handle_t *handle, struct inode *inode,
+			     loff_t lstart, loff_t length)
+{
+	struct super_block *sb = inode->i_sb;
+	struct address_space *mapping = inode->i_mapping;
+	unsigned partial_start, partial_end;
+	ext4_fsblk_t start, end;
+	loff_t byte_end = (lstart + length - 1);
+	int err = 0;
 
-		err = 0;
-		if (ext4_should_journal_data(inode)) {
-			err = ext4_handle_dirty_metadata(handle, inode, bh);
-		} else
-			mark_buffer_dirty(bh);
+	partial_start = lstart & (sb->s_blocksize - 1);
+	partial_end = byte_end & (sb->s_blocksize - 1);
 
-		BUFFER_TRACE(bh, "Partial buffer zeroed");
-next:
-		bh = bh->b_this_page;
-		iblock++;
-		pos += range_to_discard;
-	}
+	start = lstart >> sb->s_blocksize_bits;
+	end = byte_end >> sb->s_blocksize_bits;
 
+	/* Handle partial zero within the single block */
+	if (start == end &&
+	    (partial_start || (partial_end != sb->s_blocksize - 1))) {
+		err = ext4_block_zero_page_range(handle, mapping,
+						 lstart, length);
+		return err;
+	}
+	/* Handle partial zero out on the start of the range */
+	if (partial_start) {
+		err = ext4_block_zero_page_range(handle, mapping,
+						 lstart, sb->s_blocksize);
+		if (err)
+			return err;
+	}
+	/* Handle partial zero out on the end of the range */
+	if (partial_end != sb->s_blocksize - 1)
+		err = ext4_block_zero_page_range(handle, mapping,
+						 byte_end - partial_end,
+						 partial_end + 1);
 	return err;
 }
 
@@ -3580,14 +3483,12 @@ int ext4_can_truncate(struct inode *inode)
  * Returns: 0 on success or negative on failure
  */
 
-int ext4_punch_hole(struct file *file, loff_t offset, loff_t length)
+int ext4_punch_hole(struct inode *inode, loff_t offset, loff_t length)
 {
-	struct inode *inode = file_inode(file);
 	struct super_block *sb = inode->i_sb;
 	ext4_lblk_t first_block, stop_block;
 	struct address_space *mapping = inode->i_mapping;
-	loff_t first_page, last_page, page_len;
-	loff_t first_page_offset, last_page_offset;
+	loff_t first_block_offset, last_block_offset;
 	handle_t *handle;
 	unsigned int credits;
 	int ret = 0;
@@ -3638,23 +3539,16 @@ int ext4_punch_hole(struct file *file, loff_t offset, loff_t length)
 		   offset;
 	}
 
-	first_page = (offset + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
-	last_page = (offset + length) >> PAGE_CACHE_SHIFT;
+	first_block_offset = round_up(offset, sb->s_blocksize);
+	last_block_offset = round_down((offset + length), sb->s_blocksize) - 1;
 
-	first_page_offset = first_page << PAGE_CACHE_SHIFT;
-	last_page_offset = last_page << PAGE_CACHE_SHIFT;
-
-	/* Now release the pages */
-	if (last_page_offset > first_page_offset) {
-		truncate_pagecache_range(inode, first_page_offset,
-					 last_page_offset - 1);
-	}
+	/* Now release the pages and zero block aligned part of pages*/
+	if (last_block_offset > first_block_offset)
+		truncate_pagecache_range(inode, first_block_offset,
+					 last_block_offset);
 
 	/* Wait all existing dio workers, newcomers will block on i_mutex */
 	ext4_inode_block_unlocked_dio(inode);
-	ret = ext4_flush_unwritten_io(inode);
-	if (ret)
-		goto out_dio;
 	inode_dio_wait(inode);
 
 	if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
@@ -3668,66 +3562,10 @@ int ext4_punch_hole(struct file *file, loff_t offset, loff_t length)
 		goto out_dio;
 	}
 
-	/*
-	 * Now we need to zero out the non-page-aligned data in the
-	 * pages at the start and tail of the hole, and unmap the
-	 * buffer heads for the block aligned regions of the page that
-	 * were completely zeroed.
-	 */
-	if (first_page > last_page) {
-		/*
-		 * If the file space being truncated is contained
-		 * within a page just zero out and unmap the middle of
-		 * that page
-		 */
-		ret = ext4_discard_partial_page_buffers(handle,
-			mapping, offset, length, 0);
-
-		if (ret)
-			goto out_stop;
-	} else {
-		/*
-		 * zero out and unmap the partial page that contains
-		 * the start of the hole
-		 */
-		page_len = first_page_offset - offset;
-		if (page_len > 0) {
-			ret = ext4_discard_partial_page_buffers(handle, mapping,
-						offset, page_len, 0);
-			if (ret)
-				goto out_stop;
-		}
-
-		/*
-		 * zero out and unmap the partial page that contains
-		 * the end of the hole
-		 */
-		page_len = offset + length - last_page_offset;
-		if (page_len > 0) {
-			ret = ext4_discard_partial_page_buffers(handle, mapping,
-					last_page_offset, page_len, 0);
-			if (ret)
-				goto out_stop;
-		}
-	}
-
-	/*
-	 * If i_size is contained in the last page, we need to
-	 * unmap and zero the partial page after i_size
-	 */
-	if (inode->i_size >> PAGE_CACHE_SHIFT == last_page &&
-	   inode->i_size % PAGE_CACHE_SIZE != 0) {
-		page_len = PAGE_CACHE_SIZE -
-			(inode->i_size & (PAGE_CACHE_SIZE - 1));
-
-		if (page_len > 0) {
-			ret = ext4_discard_partial_page_buffers(handle,
-					mapping, inode->i_size, page_len, 0);
-
-			if (ret)
-				goto out_stop;
-		}
-	}
+	ret = ext4_zero_partial_blocks(handle, inode, offset,
+				       length);
+	if (ret)
+		goto out_stop;
 
 	first_block = (offset + sb->s_blocksize - 1) >>
 		EXT4_BLOCK_SIZE_BITS(sb);
@@ -3803,7 +3641,6 @@ void ext4_truncate(struct inode *inode)
 	unsigned int credits;
 	handle_t *handle;
 	struct address_space *mapping = inode->i_mapping;
-	loff_t page_len;
 
 	/*
 	 * There is a possibility that we're either freeing the inode
@@ -3830,12 +3667,6 @@ void ext4_truncate(struct inode *inode)
 			return;
 	}
 
-	/*
-	 * finish any pending end_io work so we won't run the risk of
-	 * converting any truncated blocks to initialized later
-	 */
-	ext4_flush_unwritten_io(inode);
-
 	if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
 		credits = ext4_writepage_trans_blocks(inode);
 	else
@@ -3847,14 +3678,8 @@ void ext4_truncate(struct inode *inode)
 		return;
 	}
 
-	if (inode->i_size % PAGE_CACHE_SIZE != 0) {
-		page_len = PAGE_CACHE_SIZE -
-			(inode->i_size & (PAGE_CACHE_SIZE - 1));
-
-		if (ext4_discard_partial_page_buffers(handle,
-				mapping, inode->i_size, page_len, 0))
-			goto out_stop;
-	}
+	if (inode->i_size & (inode->i_sb->s_blocksize - 1))
+		ext4_block_truncate_page(handle, mapping, inode->i_size);
 
 	/*
 	 * We add the inode to the orphan list, so that if this
@@ -4623,7 +4448,8 @@ static void ext4_wait_for_tail_page_commit(struct inode *inode)
 				      inode->i_size >> PAGE_CACHE_SHIFT);
 		if (!page)
 			return;
-		ret = __ext4_journalled_invalidatepage(page, offset);
+		ret = __ext4_journalled_invalidatepage(page, offset,
+						PAGE_CACHE_SIZE - offset);
 		unlock_page(page);
 		page_cache_release(page);
 		if (ret != -EBUSY)
@@ -4805,7 +4631,7 @@ int ext4_getattr(struct vfsmount *mnt, struct dentry *dentry,
 		 struct kstat *stat)
 {
 	struct inode *inode;
-	unsigned long delalloc_blocks;
+	unsigned long long delalloc_blocks;
 
 	inode = dentry->d_inode;
 	generic_fillattr(inode, stat);
@@ -4823,15 +4649,16 @@ int ext4_getattr(struct vfsmount *mnt, struct dentry *dentry,
 	delalloc_blocks = EXT4_C2B(EXT4_SB(inode->i_sb),
 				EXT4_I(inode)->i_reserved_data_blocks);
 
-	stat->blocks += (delalloc_blocks << inode->i_sb->s_blocksize_bits)>>9;
+	stat->blocks += delalloc_blocks << (inode->i_sb->s_blocksize_bits-9);
 	return 0;
 }
 
-static int ext4_index_trans_blocks(struct inode *inode, int nrblocks, int chunk)
+static int ext4_index_trans_blocks(struct inode *inode, int lblocks,
+				   int pextents)
 {
 	if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
-		return ext4_ind_trans_blocks(inode, nrblocks, chunk);
-	return ext4_ext_index_trans_blocks(inode, nrblocks, chunk);
+		return ext4_ind_trans_blocks(inode, lblocks);
+	return ext4_ext_index_trans_blocks(inode, pextents);
 }
 
 /*
@@ -4845,7 +4672,8 @@ static int ext4_index_trans_blocks(struct inode *inode, int nrblocks, int chunk)
  *
  * Also account for superblock, inode, quota and xattr blocks
  */
-static int ext4_meta_trans_blocks(struct inode *inode, int nrblocks, int chunk)
+static int ext4_meta_trans_blocks(struct inode *inode, int lblocks,
+				  int pextents)
 {
 	ext4_group_t groups, ngroups = ext4_get_groups_count(inode->i_sb);
 	int gdpblocks;
@@ -4853,14 +4681,10 @@ static int ext4_meta_trans_blocks(struct inode *inode, int nrblocks, int chunk)
 	int ret = 0;
 
 	/*
-	 * How many index blocks need to touch to modify nrblocks?
-	 * The "Chunk" flag indicating whether the nrblocks is
-	 * physically contiguous on disk
-	 *
-	 * For Direct IO and fallocate, they calls get_block to allocate
-	 * one single extent at a time, so they could set the "Chunk" flag
+	 * How many index blocks need to touch to map @lblocks logical blocks
+	 * to @pextents physical extents?
 	 */
-	idxblocks = ext4_index_trans_blocks(inode, nrblocks, chunk);
+	idxblocks = ext4_index_trans_blocks(inode, lblocks, pextents);
 
 	ret = idxblocks;
 
@@ -4868,12 +4692,7 @@ static int ext4_meta_trans_blocks(struct inode *inode, int nrblocks, int chunk)
 	 * Now let's see how many group bitmaps and group descriptors need
 	 * to account
 	 */
-	groups = idxblocks;
-	if (chunk)
-		groups += 1;
-	else
-		groups += nrblocks;
-
+	groups = idxblocks + pextents;
 	gdpblocks = groups;
 	if (groups > ngroups)
 		groups = ngroups;
@@ -4904,7 +4723,7 @@ int ext4_writepage_trans_blocks(struct inode *inode)
 	int bpp = ext4_journal_blocks_per_page(inode);
 	int ret;
 
-	ret = ext4_meta_trans_blocks(inode, bpp, 0);
+	ret = ext4_meta_trans_blocks(inode, bpp, bpp);
 
 	/* Account for data blocks for journalled mode */
 	if (ext4_should_journal_data(inode))