1 files changed, 73 insertions, 12 deletions

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 89c92c0f829..b6fa0c4087e 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1783,6 +1783,39 @@ static inline void __unmap_underlying_blocks(struct inode *inode,
                 unmap_underlying_metadata(bdev, bh->b_blocknr + i);
 }
 
+static void ext4_da_block_invalidatepages(struct mpage_da_data *mpd,
+                                        sector_t logical, long blk_cnt)
+{
+        int nr_pages, i;
+        pgoff_t index, end;
+        struct pagevec pvec;
+        struct inode *inode = mpd->inode;
+        struct address_space *mapping = inode->i_mapping;
+
+        index = logical >> (PAGE_CACHE_SHIFT - inode->i_blkbits);
+        end   = (logical + blk_cnt - 1) >>
+                                (PAGE_CACHE_SHIFT - inode->i_blkbits);
+        while (index <= end) {
+                nr_pages = pagevec_lookup(&pvec, mapping, index, PAGEVEC_SIZE);
+                if (nr_pages == 0)
+                        break;
+                for (i = 0; i < nr_pages; i++) {
+                        struct page *page = pvec.pages[i];
+                        index = page->index;
+                        if (index > end)
+                                break;
+                        index++;
+
+                        BUG_ON(!PageLocked(page));
+                        BUG_ON(PageWriteback(page));
+                        block_invalidatepage(page, 0);
+                        ClearPageUptodate(page);
+                        unlock_page(page);
+                }
+        }
+        return;
+}
+
 /*
  * mpage_da_map_blocks - go through given space
  *
@@ -1792,7 +1825,7 @@ static inline void __unmap_underlying_blocks(struct inode *inode,
  * The function skips space we know is already mapped to disk blocks.
  *
  */
-static void mpage_da_map_blocks(struct mpage_da_data *mpd)
+static int  mpage_da_map_blocks(struct mpage_da_data *mpd)
 {
         int err = 0;
         struct buffer_head *lbh = &mpd->lbh;
@@ -1803,7 +1836,7 @@ static void mpage_da_map_blocks(struct mpage_da_data *mpd)
          * We consider only non-mapped and non-allocated blocks
          */
         if (buffer_mapped(lbh) && !buffer_delay(lbh))
-                return;
+                return 0;
 
         new.b_state = lbh->b_state;
         new.b_blocknr = 0;
@@ -1814,10 +1847,38 @@ static void mpage_da_map_blocks(struct mpage_da_data *mpd)
          * to write simply return
          */
         if (!new.b_size)
-                return;
+                return 0;
         err = mpd->get_block(mpd->inode, next, &new, 1);
-        if (err)
-                return;
+        if (err) {
+
+                /* If get block returns with error
+                 * we simply return. Later writepage
+                 * will redirty the page and writepages
+                 * will find the dirty page again
+                 */
+                if (err == -EAGAIN)
+                        return 0;
+                /*
+                 * 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.
+                 */
+                printk(KERN_EMERG "%s block allocation failed for inode %lu "
+                                  "at logical offset %llu with max blocks "
+                                  "%zd with error %d\n",
+                                  __func__, mpd->inode->i_ino,
+                                  (unsigned long long)next,
+                                  lbh->b_size >> mpd->inode->i_blkbits, err);
+                printk(KERN_EMERG "This should not happen.!! "
+                                        "Data will be lost\n");
+                /* invlaidate all the pages */
+                ext4_da_block_invalidatepages(mpd, next,
+                                lbh->b_size >> mpd->inode->i_blkbits);
+                return err;
+        }
         BUG_ON(new.b_size == 0);
 
         if (buffer_new(&new))
@@ -1830,7 +1891,7 @@ static void mpage_da_map_blocks(struct mpage_da_data *mpd)
         if (buffer_delay(lbh) || buffer_unwritten(lbh))
                 mpage_put_bnr_to_bhs(mpd, next, &new);
 
-        return;
+        return 0;
 }
 
 #define BH_FLAGS ((1 << BH_Uptodate) | (1 << BH_Mapped) | \
@@ -1899,8 +1960,8 @@ 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_blocks(mpd);
-        mpage_da_submit_io(mpd);
+        if (mpage_da_map_blocks(mpd) == 0)
+                mpage_da_submit_io(mpd);
         mpd->io_done = 1;
         return;
 }
@@ -1942,8 +2003,8 @@ static int __mpage_da_writepage(struct page *page,
                  * and start IO on them using writepage()
                  */
                 if (mpd->next_page != mpd->first_page) {
-                        mpage_da_map_blocks(mpd);
-                        mpage_da_submit_io(mpd);
+                        if (mpage_da_map_blocks(mpd) == 0)
+                                mpage_da_submit_io(mpd);
                         /*
                          * skip rest of the page in the page_vec
                          */
@@ -2046,8 +2107,8 @@ static int mpage_da_writepages(struct address_space *mapping,
          * Handle last extent of pages
          */
         if (!mpd.io_done && mpd.next_page != mpd.first_page) {
-                mpage_da_map_blocks(&mpd);
-                mpage_da_submit_io(&mpd);
+                if (mpage_da_map_blocks(&mpd) == 0)
+                        mpage_da_submit_io(&mpd);
         }
 
         wbc->nr_to_write = to_write - mpd.pages_written;