mm: move vmtruncate_range to truncate.c

You would expect to find vmtruncate_range() next to vmtruncate() in
mm/truncate.c: move it there.

Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 24 insertions, 0 deletions

diff --git a/mm/truncate.c b/mm/truncate.c
index 3a29a6180212..5b4c3a4847e9 100644
--- a/mm/truncate.c
+++ b/mm/truncate.c
@@ -603,3 +603,27 @@ 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);
+        truncate_inode_pages_range(mapping, offset, end);
+        unmap_mapping_range(mapping, offset, (end - offset), 1);
+        inode->i_op->truncate_range(inode, offset, end);
+        up_write(&inode->i_alloc_sem);
+        mutex_unlock(&inode->i_mutex);
+
+        return 0;
+}