1 files changed, 99 insertions, 7 deletions

diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index a38f32427826..d279ea8c4661 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -2138,6 +2138,80 @@ void ext4_ext_release(struct super_block *sb)
 #endif
 }
 
+static void bi_complete(struct bio *bio, int error)
+{
+        complete((struct completion *)bio->bi_private);
+}
+
+/* FIXME!! we need to try to merge to left or right after zero-out  */
+static int ext4_ext_zeroout(struct inode *inode, struct ext4_extent *ex)
+{
+        int ret = -EIO;
+        struct bio *bio;
+        int blkbits, blocksize;
+        sector_t ee_pblock;
+        struct completion event;
+        unsigned int ee_len, len, done, offset;
+
+
+        blkbits   = inode->i_blkbits;
+        blocksize = inode->i_sb->s_blocksize;
+        ee_len    = ext4_ext_get_actual_len(ex);
+        ee_pblock = ext_pblock(ex);
+
+        /* convert ee_pblock to 512 byte sectors */
+        ee_pblock = ee_pblock << (blkbits - 9);
+
+        while (ee_len > 0) {
+
+                if (ee_len > BIO_MAX_PAGES)
+                        len = BIO_MAX_PAGES;
+                else
+                        len = ee_len;
+
+                bio = bio_alloc(GFP_NOIO, len);
+                if (!bio)
+                        return -ENOMEM;
+                bio->bi_sector = ee_pblock;
+                bio->bi_bdev   = inode->i_sb->s_bdev;
+
+                done = 0;
+                offset = 0;
+                while (done < len) {
+                        ret = bio_add_page(bio, ZERO_PAGE(0),
+                                                        blocksize, offset);
+                        if (ret != blocksize) {
+                                /*
+                                 * We can't add any more pages because of
+                                 * hardware limitations.  Start a new bio.
+                                 */
+                                break;
+                        }
+                        done++;
+                        offset += blocksize;
+                        if (offset >= PAGE_CACHE_SIZE)
+                                offset = 0;
+                }
+
+                init_completion(&event);
+                bio->bi_private = &event;
+                bio->bi_end_io = bi_complete;
+                submit_bio(WRITE, bio);
+                wait_for_completion(&event);
+
+                if (test_bit(BIO_UPTODATE, &bio->bi_flags))
+                        ret = 0;
+                else {
+                        ret = -EIO;
+                        break;
+                }
+                bio_put(bio);
+                ee_len    -= done;
+                ee_pblock += done  << (blkbits - 9);
+        }
+        return ret;
+}
+
 /*
  * This function is called by ext4_ext_get_blocks() if someone tries to write
  * to an uninitialized extent. It may result in splitting the uninitialized
@@ -2204,14 +2278,19 @@ static int ext4_ext_convert_to_initialized(handle_t *handle,
                 ex3->ee_len = cpu_to_le16(allocated - max_blocks);
                 ext4_ext_mark_uninitialized(ex3);
                 err = ext4_ext_insert_extent(handle, inode, path, ex3);
-                if (err) {
+                if (err == -ENOSPC) {
+                        err =  ext4_ext_zeroout(inode, &orig_ex);
+                        if (err)
+                                goto fix_extent_len;
+                        /* update the extent length and mark as initialized */
                         ex->ee_block = orig_ex.ee_block;
                         ex->ee_len   = orig_ex.ee_len;
                         ext4_ext_store_pblock(ex, ext_pblock(&orig_ex));
-                        ext4_ext_mark_uninitialized(ex);
                         ext4_ext_dirty(handle, inode, path + depth);
-                        goto out;
-                }
+                        return le16_to_cpu(ex->ee_len);
+
+                } else if (err)
+                        goto fix_extent_len;
                 /*
                  * The depth, and hence eh & ex might change
                  * as part of the insert above.
@@ -2297,15 +2376,28 @@ static int ext4_ext_convert_to_initialized(handle_t *handle,
         goto out;
 insert:
         err = ext4_ext_insert_extent(handle, inode, path, &newex);
-        if (err) {
+        if (err == -ENOSPC) {
+                err =  ext4_ext_zeroout(inode, &orig_ex);
+                if (err)
+                        goto fix_extent_len;
+                /* update the extent length and mark as initialized */
                 ex->ee_block = orig_ex.ee_block;
                 ex->ee_len   = orig_ex.ee_len;
                 ext4_ext_store_pblock(ex, ext_pblock(&orig_ex));
-                ext4_ext_mark_uninitialized(ex);
                 ext4_ext_dirty(handle, inode, path + depth);
-        }
+                return le16_to_cpu(ex->ee_len);
+        } else if (err)
+                goto fix_extent_len;
 out:
         return err ? err : allocated;
+
+fix_extent_len:
+        ex->ee_block = orig_ex.ee_block;
+        ex->ee_len   = orig_ex.ee_len;
+        ext4_ext_store_pblock(ex, ext_pblock(&orig_ex));
+        ext4_ext_mark_uninitialized(ex);
+        ext4_ext_dirty(handle, inode, path + depth);
+        return err;
 }
 
 /*