3 files changed, 134 insertions, 55 deletions

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 751277a4890c..1bbd2caebe7f 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1893,7 +1893,6 @@ extern int ext4_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf);
 extern qsize_t *ext4_get_reserved_space(struct inode *inode);
 extern void ext4_da_update_reserve_space(struct inode *inode,
                                         int used, int quota_claim);
-extern int ext4_da_reserve_space(struct inode *inode, ext4_lblk_t lblock);
 
 /* indirect.c */
 extern int ext4_ind_map_blocks(handle_t *handle, struct inode *inode,
@@ -2300,10 +2299,14 @@ enum ext4_state_bits {
                                  * never, ever appear in a buffer_head's state
                                  * flag. See EXT4_MAP_FROM_CLUSTER to see where
                                  * this is used. */
+        BH_Da_Mapped,   /* Delayed allocated block that now has a mapping. This
+                         * flag is set when ext4_map_blocks is called on a
+                         * delayed allocated block to get its real mapping. */
 };
 
 BUFFER_FNS(Uninit, uninit)
 TAS_BUFFER_FNS(Uninit, uninit)
+BUFFER_FNS(Da_Mapped, da_mapped)
 
 /*
  * Add new method to test wether block and inode bitmaps are properly
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 9b119308daea..ad39627c1fbc 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -3296,28 +3296,9 @@ static int ext4_find_delalloc_range(struct inode *inode,
 
         while ((i >= lblk_start) && (i <= lblk_end)) {
                 page = find_get_page(mapping, index);
-                if (!page || !PageDirty(page))
+                if (!page)
                         goto nextpage;
 
-                if (PageWriteback(page)) {
-                        /*
-                         * This might be a race with allocation and writeout. In
-                         * this case we just assume that the rest of the range
-                         * will eventually be written and there wont be any
-                         * delalloc blocks left.
-                         * TODO: the above assumption is troublesome, but might
-                         * work better in practice. other option could be note
-                         * somewhere that the cluster is getting written out and
-                         * detect that here.
-                         */
-                        page_cache_release(page);
-                        trace_ext4_find_delalloc_range(inode,
-                                        lblk_start, lblk_end,
-                                        search_hint_reverse,
-                                        0, i);
-                        return 0;
-                }
-
                 if (!page_has_buffers(page))
                         goto nextpage;
 
@@ -3340,7 +3321,11 @@ static int ext4_find_delalloc_range(struct inode *inode,
                                 continue;
                         }
 
-                        if (buffer_delay(bh)) {
+                        /* Check if the buffer is delayed allocated and that it
+                         * is not yet mapped. (when da-buffers are mapped during
+                         * their writeout, their da_mapped bit is set.)
+                         */
+                        if (buffer_delay(bh) && !buffer_da_mapped(bh)) {
                                 page_cache_release(page);
                                 trace_ext4_find_delalloc_range(inode,
                                                 lblk_start, lblk_end,
@@ -4106,6 +4091,7 @@ got_allocated_blocks:
                         ext4_da_update_reserve_space(inode, allocated_clusters,
                                                         1);
                         if (reserved_clusters < allocated_clusters) {
+                                struct ext4_inode_info *ei = EXT4_I(inode);
                                 int reservation = allocated_clusters -
                                                   reserved_clusters;
                                 /*
@@ -4148,11 +4134,11 @@ got_allocated_blocks:
                                  *   remaining blocks finally gets written, we
                                  *   could claim them.
                                  */
-                                while (reservation) {
-                                        ext4_da_reserve_space(inode,
-                                                              map->m_lblk);
-                                        reservation--;
-                                }
+                                dquot_reserve_block(inode,
+                                                EXT4_C2B(sbi, reservation));
+                                spin_lock(&ei->i_block_reservation_lock);
+                                ei->i_reserved_data_blocks += reservation;
+                                spin_unlock(&ei->i_block_reservation_lock);
                         }
                 }
         }
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 2dcd4fed96ec..1380cd29c312 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -398,6 +398,49 @@ static pgoff_t ext4_num_dirty_pages(struct inode *inode, pgoff_t idx,
 }
 
 /*
+ * Sets the BH_Da_Mapped bit on the buffer heads corresponding to the given map.
+ */
+static void set_buffers_da_mapped(struct inode *inode,
+                                   struct ext4_map_blocks *map)
+{
+        struct address_space *mapping = inode->i_mapping;
+        struct pagevec pvec;
+        int i, nr_pages;
+        pgoff_t index, end;
+
+        index = map->m_lblk >> (PAGE_CACHE_SHIFT - inode->i_blkbits);
+        end = (map->m_lblk + map->m_len - 1) >>
+                (PAGE_CACHE_SHIFT - inode->i_blkbits);
+
+        pagevec_init(&pvec, 0);
+        while (index <= end) {
+                nr_pages = pagevec_lookup(&pvec, mapping, index,
+                                          min(end - index + 1,
+                                              (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;
+
+                        if (unlikely(page->mapping != mapping) ||
+                            !PageDirty(page))
+                                break;
+
+                        if (page_has_buffers(page)) {
+                                bh = head = page_buffers(page);
+                                do {
+                                        set_buffer_da_mapped(bh);
+                                        bh = bh->b_this_page;
+                                } while (bh != head);
+                        }
+                        index++;
+                }
+                pagevec_release(&pvec);
+        }
+}
+
+/*
  * The ext4_map_blocks() function tries to look up the requested blocks,
  * and returns if the blocks are already mapped.
  *
@@ -516,9 +559,17 @@ int ext4_map_blocks(handle_t *handle, struct inode *inode,
                         (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE))
                         ext4_da_update_reserve_space(inode, retval, 1);
         }
-        if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
+        if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) {
                 ext4_clear_inode_state(inode, EXT4_STATE_DELALLOC_RESERVED);
 
+                /* If we have successfully mapped the delayed allocated blocks,
+                 * set the BH_Da_Mapped bit on them. Its important to do this
+                 * under the protection of i_data_sem.
+                 */
+                if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED)
+                        set_buffers_da_mapped(inode, map);
+        }
+
         up_write((&EXT4_I(inode)->i_data_sem));
         if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED) {
                 int ret = check_block_validity(inode, map);
@@ -1038,7 +1089,7 @@ static int ext4_journalled_write_end(struct file *file,
 /*
  * Reserve a single cluster located at lblock
  */
-int ext4_da_reserve_space(struct inode *inode, ext4_lblk_t lblock)
+static int ext4_da_reserve_space(struct inode *inode, ext4_lblk_t lblock)
 {
         int retries = 0;
         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
@@ -1153,6 +1204,7 @@ static void ext4_da_page_release_reservation(struct page *page,
                 if ((offset <= curr_off) && (buffer_delay(bh))) {
                         to_release++;
                         clear_buffer_delay(bh);
+                        clear_buffer_da_mapped(bh);
                 }
                 curr_off = next_off;
         } while ((bh = bh->b_this_page) != head);
@@ -1271,6 +1323,8 @@ static int mpage_da_submit_io(struct mpage_da_data *mpd,
                                                 clear_buffer_delay(bh);
                                                 bh->b_blocknr = pblock;
                                         }
+                                        if (buffer_da_mapped(bh))
+                                                clear_buffer_da_mapped(bh);
                                         if (buffer_unwritten(bh) ||
                                             buffer_mapped(bh))
                                                 BUG_ON(bh->b_blocknr != pblock);
@@ -1604,6 +1658,66 @@ static int ext4_bh_delay_or_unwritten(handle_t *handle, struct buffer_head *bh)
 }
 
 /*
+ * This function is grabs code from the very beginning of
+ * ext4_map_blocks, but assumes that the caller is from delayed write
+ * time. This function looks up the requested blocks and sets the
+ * buffer delay bit under the protection of i_data_sem.
+ */
+static int ext4_da_map_blocks(struct inode *inode, sector_t iblock,
+                              struct ext4_map_blocks *map,
+                              struct buffer_head *bh)
+{
+        int retval;
+        sector_t invalid_block = ~((sector_t) 0xffff);
+
+        if (invalid_block < ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es))
+                invalid_block = ~0;
+
+        map->m_flags = 0;
+        ext_debug("ext4_da_map_blocks(): inode %lu, max_blocks %u,"
+                  "logical block %lu\n", inode->i_ino, map->m_len,
+                  (unsigned long) map->m_lblk);
+        /*
+         * Try to see if we can get the block without requesting a new
+         * file system block.
+         */
+        down_read((&EXT4_I(inode)->i_data_sem));
+        if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
+                retval = ext4_ext_map_blocks(NULL, inode, map, 0);
+        else
+                retval = ext4_ind_map_blocks(NULL, inode, map, 0);
+
+        if (retval == 0) {
+                /*
+                 * XXX: __block_prepare_write() unmaps passed block,
+                 * is it OK?
+                 */
+                /* If the block was allocated from previously allocated cluster,
+                 * then we dont need to reserve it again. */
+                if (!(map->m_flags & EXT4_MAP_FROM_CLUSTER)) {
+                        retval = ext4_da_reserve_space(inode, iblock);
+                        if (retval)
+                                /* not enough space to reserve */
+                                goto out_unlock;
+                }
+
+                /* Clear EXT4_MAP_FROM_CLUSTER flag since its purpose is served
+                 * and it should not appear on the bh->b_state.
+                 */
+                map->m_flags &= ~EXT4_MAP_FROM_CLUSTER;
+
+                map_bh(bh, inode->i_sb, invalid_block);
+                set_buffer_new(bh);
+                set_buffer_delay(bh);
+        }
+
+out_unlock:
+        up_read((&EXT4_I(inode)->i_data_sem));
+
+        return retval;
+}
+
+/*
  * This is a special get_blocks_t callback which is used by
  * ext4_da_write_begin().  It will either return mapped block or
  * reserve space for a single block.
@@ -1620,10 +1734,6 @@ static int ext4_da_get_block_prep(struct inode *inode, sector_t iblock,
 {
         struct ext4_map_blocks map;
         int ret = 0;
-        sector_t invalid_block = ~((sector_t) 0xffff);
-
-        if (invalid_block < ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es))
-                invalid_block = ~0;
 
         BUG_ON(create == 0);
         BUG_ON(bh->b_size != inode->i_sb->s_blocksize);
@@ -1636,29 +1746,9 @@ static int ext4_da_get_block_prep(struct inode *inode, sector_t iblock,
          * preallocated blocks are unmapped but should treated
          * the same as allocated blocks.
          */
-        ret = ext4_map_blocks(NULL, inode, &map, 0);
-        if (ret < 0)
+        ret = ext4_da_map_blocks(inode, iblock, &map, bh);
+        if (ret <= 0)
                 return ret;
-        if (ret == 0) {
-                if (buffer_delay(bh))
-                        return 0; /* Not sure this could or should happen */
-                /*
-                 * XXX: __block_write_begin() unmaps passed block, is it OK?
-                 */
-                /* If the block was allocated from previously allocated cluster,
-                 * then we dont need to reserve it again. */
-                if (!(map.m_flags & EXT4_MAP_FROM_CLUSTER)) {
-                        ret = ext4_da_reserve_space(inode, iblock);
-                        if (ret)
-                                /* not enough space to reserve */
-                                return ret;
-                }
-
-                map_bh(bh, inode->i_sb, invalid_block);
-                set_buffer_new(bh);
-                set_buffer_delay(bh);
-                return 0;
-        }
 
         map_bh(bh, inode->i_sb, map.m_pblk);
         bh->b_state = (bh->b_state & ~EXT4_MAP_FLAGS) | map.m_flags;