diff --git a/extent_ranges.cc b/extent_ranges.cc
index 326dbbd..b425a86 100644
--- a/extent_ranges.cc
+++ b/extent_ranges.cc
@@ -223,4 +223,55 @@
   return out;
 }
 
+vector<Extent> FilterExtentRanges(const std::vector<Extent>& extents,
+                                  const ExtentRanges& ranges) {
+  vector<Extent> result;
+  const ExtentRanges::ExtentSet& extent_set = ranges.extent_set();
+  for (Extent extent : extents) {
+    // The extents are sorted by the start_block. We want to iterate all the
+    // Extents in the ExtentSet possibly overlapping the current |extent|. This
+    // is achieved by looking from the extent whose start_block is *lower* than
+    // the extent.start_block() up to the greatest extent whose start_block is
+    // lower than extent.start_block() + extent.num_blocks().
+    auto lower = extent_set.lower_bound(extent);
+    // We need to decrement the lower_bound to look at the extent that could
+    // overlap the beginning of the current |extent|.
+    if (lower != extent_set.begin())
+      lower--;
+    auto upper = extent_set.lower_bound(
+        ExtentForRange(extent.start_block() + extent.num_blocks(), 0));
+    for (auto iter = lower; iter != upper; ++iter) {
+      if (!ExtentRanges::ExtentsOverlap(extent, *iter))
+        continue;
+      if (iter->start_block() <= extent.start_block()) {
+        // We need to cut blocks from the beginning of the |extent|.
+        uint64_t cut_blocks = iter->start_block() + iter->num_blocks() -
+            extent.start_block();
+        if (cut_blocks >= extent.num_blocks()) {
+          extent.set_num_blocks(0);
+          break;
+        }
+        extent = ExtentForRange(extent.start_block() + cut_blocks,
+                                extent.num_blocks() - cut_blocks);
+      } else {
+        // We need to cut blocks on the middle of the extent, possible up to the
+        // end of it.
+        result.push_back(
+            ExtentForRange(extent.start_block(),
+                           iter->start_block() - extent.start_block()));
+        uint64_t new_start = iter->start_block() + iter->num_blocks();
+        uint64_t old_end = extent.start_block() + extent.num_blocks();
+        if (new_start >= old_end) {
+          extent.set_num_blocks(0);
+          break;
+        }
+        extent = ExtentForRange(new_start, old_end - new_start);
+      }
+    }
+    if (extent.num_blocks() > 0)
+      result.push_back(extent);
+  }
+  return result;
+}
+
 }  // namespace chromeos_update_engine
diff --git a/extent_ranges.h b/extent_ranges.h
index 4376d05..ec3547c 100644
--- a/extent_ranges.h
+++ b/extent_ranges.h
@@ -68,6 +68,12 @@
   uint64_t blocks_;
 };
 
+// Filters out from the passed list of extents |extents| all the blocks in the
+// ExtentRanges set. Note that the order of the blocks in |extents| is preserved
+// omitting blocks present in the ExtentRanges |ranges|.
+std::vector<Extent> FilterExtentRanges(const std::vector<Extent>& extents,
+                                       const ExtentRanges& ranges);
+
 }  // namespace chromeos_update_engine
 
 #endif  // UPDATE_ENGINE_EXTENT_RANGES_H_
diff --git a/extent_ranges_unittest.cc b/extent_ranges_unittest.cc
index b4de3bc..7624f3d 100644
--- a/extent_ranges_unittest.cc
+++ b/extent_ranges_unittest.cc
@@ -9,6 +9,7 @@
 #include <gtest/gtest.h>
 
 #include "update_engine/payload_constants.h"
+#include "update_engine/payload_generator/extent_utils.h"
 #include "update_engine/test_utils.h"
 
 using std::vector;
@@ -255,4 +256,59 @@
   }
 }
 
+TEST(ExtentRangesTest, FilterExtentRangesEmptyRanges) {
+  ExtentRanges ranges;
+  EXPECT_EQ(vector<Extent>(),
+            FilterExtentRanges(vector<Extent>(), ranges));
+  EXPECT_EQ(
+      vector<Extent>{ ExtentForRange(50, 10) },
+      FilterExtentRanges(vector<Extent>{ ExtentForRange(50, 10) }, ranges));
+  // Check that the empty Extents are ignored.
+  EXPECT_EQ(
+      (vector<Extent>{ ExtentForRange(10, 10), ExtentForRange(20, 10) }),
+      FilterExtentRanges(vector<Extent>{
+           ExtentForRange(10, 10),
+           ExtentForRange(3, 0),
+           ExtentForRange(20, 10) }, ranges));
+}
+
+TEST(ExtentRangesTest, FilterExtentRangesMultipleRanges) {
+  // Two overlaping extents, with three ranges to remove.
+  vector<Extent> extents {
+      ExtentForRange(10, 100),
+      ExtentForRange(30, 100) };
+  ExtentRanges ranges;
+  // This overlaps the beginning of the second extent.
+  ranges.AddExtent(ExtentForRange(28, 3));
+  ranges.AddExtent(ExtentForRange(50, 10));
+  ranges.AddExtent(ExtentForRange(70, 10));
+  // This overlaps the end of the second extent.
+  ranges.AddExtent(ExtentForRange(108, 6));
+  EXPECT_EQ(
+      (vector<Extent>{
+           // For the first extent:
+           ExtentForRange(10, 18),
+           ExtentForRange(31, 19),
+           ExtentForRange(60, 10),
+           ExtentForRange(80, 28),
+           // For the second extent:
+           ExtentForRange(31, 19),
+           ExtentForRange(60, 10),
+           ExtentForRange(80, 28),
+           ExtentForRange(114, 16)}),
+      FilterExtentRanges(extents, ranges));
+}
+
+TEST(ExtentRangesTest, FilterExtentRangesOvelapping) {
+  ExtentRanges ranges;
+  ranges.AddExtent(ExtentForRange(10, 3));
+  ranges.AddExtent(ExtentForRange(20, 5));
+  // Requested extent overlaps with one of the ranges.
+  EXPECT_EQ(vector<Extent>(),
+            FilterExtentRanges(vector<Extent>{
+                                   ExtentForRange(10, 1),
+                                   ExtentForRange(22, 1) },
+                               ranges));
+}
+
 }  // namespace chromeos_update_engine