1 files changed, 35 insertions, 0 deletions

diff --git a/mm/truncate.c b/mm/truncate.c
index a9566752913..e13f22efaad 100644
--- a/mm/truncate.c
+++ b/mm/truncate.c
@@ -19,6 +19,7 @@
 #include <linux/task_io_accounting_ops.h>
 #include <linux/buffer_head.h>	/* grr. try_to_release_page,
 				   do_invalidatepage */
+#include <linux/cleancache.h>
 #include "internal.h"
 
 
@@ -51,6 +52,7 @@ void do_invalidatepage(struct page *page, unsigned long offset)
 static inline void truncate_partial_page(struct page *page, unsigned partial)
 {
 	zero_user_segment(page, partial, PAGE_CACHE_SIZE);
+	cleancache_flush_page(page->mapping, page);
 	if (page_has_private(page))
 		do_invalidatepage(page, partial);
 }
@@ -214,6 +216,7 @@ void truncate_inode_pages_range(struct address_space *mapping,
 	pgoff_t next;
 	int i;
 
+	cleancache_flush_inode(mapping);
 	if (mapping->nrpages == 0)
 		return;
 
@@ -291,6 +294,7 @@ void truncate_inode_pages_range(struct address_space *mapping,
 		pagevec_release(&pvec);
 		mem_cgroup_uncharge_end();
 	}
+	cleancache_flush_inode(mapping);
 }
 EXPORT_SYMBOL(truncate_inode_pages_range);
 
@@ -300,6 +304,11 @@ EXPORT_SYMBOL(truncate_inode_pages_range);
  * @lstart: offset from which to truncate
  *
  * Called under (and serialised by) inode->i_mutex.
+ *
+ * Note: When this function returns, there can be a page in the process of
+ * deletion (inside __delete_from_page_cache()) in the specified range.  Thus
+ * mapping->nrpages can be non-zero when this function returns even after
+ * truncation of the whole mapping.
  */
 void truncate_inode_pages(struct address_space *mapping, loff_t lstart)
 {
@@ -440,6 +449,7 @@ int invalidate_inode_pages2_range(struct address_space *mapping,
 	int did_range_unmap = 0;
 	int wrapped = 0;
 
+	cleancache_flush_inode(mapping);
 	pagevec_init(&pvec, 0);
 	next = start;
 	while (next <= end && !wrapped &&
@@ -498,6 +508,7 @@ int invalidate_inode_pages2_range(struct address_space *mapping,
 		mem_cgroup_uncharge_end();
 		cond_resched();
 	}
+	cleancache_flush_inode(mapping);
 	return ret;
 }
 EXPORT_SYMBOL_GPL(invalidate_inode_pages2_range);
@@ -597,3 +608,27 @@ int vmtruncate(struct inode *inode, loff_t offset)
 	return 0;
 }
 EXPORT_SYMBOL(vmtruncate);
+
+int vmtruncate_range(struct inode *inode, loff_t offset, loff_t end)
+{
+	struct address_space *mapping = inode->i_mapping;
+
+	/*
+	 * If the underlying filesystem is not going to provide
+	 * a way to truncate a range of blocks (punch a hole) -
+	 * we should return failure right now.
+	 */
+	if (!inode->i_op->truncate_range)
+		return -ENOSYS;
+
+	mutex_lock(&inode->i_mutex);
+	down_write(&inode->i_alloc_sem);
+	unmap_mapping_range(mapping, offset, (end - offset), 1);
+	inode->i_op->truncate_range(inode, offset, end);
+	/* unmap again to remove racily COWed private pages */
+	unmap_mapping_range(mapping, offset, (end - offset), 1);
+	up_write(&inode->i_alloc_sem);
+	mutex_unlock(&inode->i_mutex);
+
+	return 0;
+}