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))