diff options
| -rw-r--r-- | fs/cifs/inode.c | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c index dd4167762a8..97ccc513730 100644 --- a/fs/cifs/inode.c +++ b/fs/cifs/inode.c @@ -1377,8 +1377,17 @@ static int cifs_vmtruncate(struct inode *inode, loff_t offset) } i_size_write(inode, offset); spin_unlock(&inode->i_lock); + /* + * unmap_mapping_range is called twice, first simply for efficiency + * so that truncate_inode_pages does fewer single-page unmaps. However + * after this first call, and before truncate_inode_pages finishes, + * it is possible for private pages to be COWed, which remain after + * truncate_inode_pages finishes, hence the second unmap_mapping_range + * call must be made for correctness. + */ unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1); truncate_inode_pages(mapping, offset); + unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1); goto out_truncate; do_expand: |