1 files changed, 10 insertions, 23 deletions

diff --git a/fs/block_dev.c b/fs/block_dev.c
index 2091db8cdd78..c7bda5cd3da7 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -58,17 +58,24 @@ static void bdev_inode_switch_bdi(struct inode *inode,
                         struct backing_dev_info *dst)
 {
         struct backing_dev_info *old = inode->i_data.backing_dev_info;
+        bool wakeup_bdi = false;
 
         if (unlikely(dst == old))               /* deadlock avoidance */
                 return;
         bdi_lock_two(&old->wb, &dst->wb);
         spin_lock(&inode->i_lock);
         inode->i_data.backing_dev_info = dst;
-        if (inode->i_state & I_DIRTY)
+        if (inode->i_state & I_DIRTY) {
+                if (bdi_cap_writeback_dirty(dst) && !wb_has_dirty_io(&dst->wb))
+                        wakeup_bdi = true;
                 list_move(&inode->i_wb_list, &dst->wb.b_dirty);
+        }
         spin_unlock(&inode->i_lock);
         spin_unlock(&old->wb.list_lock);
         spin_unlock(&dst->wb.list_lock);
+
+        if (wakeup_bdi)
+                bdi_wakeup_thread_delayed(dst);
 }
 
 /* Kill _all_ buffers and pagecache , dirty or not.. */
@@ -325,31 +332,10 @@ static int blkdev_write_end(struct file *file, struct address_space *mapping,
 static loff_t block_llseek(struct file *file, loff_t offset, int whence)
 {
         struct inode *bd_inode = file->f_mapping->host;
-        loff_t size;
         loff_t retval;
 
         mutex_lock(&bd_inode->i_mutex);
-        size = i_size_read(bd_inode);
-
-        retval = -EINVAL;
-        switch (whence) {
-                case SEEK_END:
-                        offset += size;
-                        break;
-                case SEEK_CUR:
-                        offset += file->f_pos;
-                case SEEK_SET:
-                        break;
-                default:
-                        goto out;
-        }
-        if (offset >= 0 && offset <= size) {
-                if (offset != file->f_pos) {
-                        file->f_pos = offset;
-                }
-                retval = offset;
-        }
-out:
+        retval = fixed_size_llseek(file, offset, whence, i_size_read(bd_inode));
         mutex_unlock(&bd_inode->i_mutex);
         return retval;
 }
@@ -1583,6 +1569,7 @@ static const struct address_space_operations def_blk_aops = {
         .writepages     = generic_writepages,
         .releasepage    = blkdev_releasepage,
         .direct_IO      = blkdev_direct_IO,
+        .is_dirty_writeback = buffer_check_dirty_writeback,
 };
 
 const struct file_operations def_blk_fops = {