vfs: Introduce filemap_fdatawait_range
This simple helper saves some filesystems conversion from byte offset
to page numbers and also makes the fdata* interface more complete.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
diff --git a/mm/filemap.c b/mm/filemap.c
index ccea3b6..65b2e50 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -307,6 +307,26 @@
}
/**
+ * filemap_fdatawait_range - wait for all under-writeback pages to complete in a given range
+ * @mapping: address space structure to wait for
+ * @start: offset in bytes where the range starts
+ * @end: offset in bytes where the range ends (inclusive)
+ *
+ * Walk the list of under-writeback pages of the given address space
+ * in the given range and wait for all of them.
+ *
+ * This is just a simple wrapper so that callers don't have to convert offsets
+ * to page indexes themselves
+ */
+int filemap_fdatawait_range(struct address_space *mapping, loff_t start,
+ loff_t end)
+{
+ return wait_on_page_writeback_range(mapping, start >> PAGE_CACHE_SHIFT,
+ end >> PAGE_CACHE_SHIFT);
+}
+EXPORT_SYMBOL(filemap_fdatawait_range);
+
+/**
* sync_page_range - write and wait on all pages in the passed range
* @inode: target inode
* @mapping: target address_space
