Merge git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable

[pandora-kernel.git] / fs / btrfs / extent_io.c

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index fd3f172..714adc4 100644 (file)
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -3046,17 +3046,38 @@ int extent_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
        }
 
        while (!end) {
-               off = extent_map_end(em);
-               if (off >= max)
-                       end = 1;
+               u64 offset_in_extent;
+
+               /* break if the extent we found is outside the range */
+               if (em->start >= max || extent_map_end(em) < off)
+                       break;
+
+               /*
+                * get_extent may return an extent that starts before our
+                * requested range.  We have to make sure the ranges
+                * we return to fiemap always move forward and don't
+                * overlap, so adjust the offsets here
+                */
+               em_start = max(em->start, off);
 
-               em_start = em->start;
-               em_len = em->len;
+               /*
+                * record the offset from the start of the extent
+                * for adjusting the disk offset below
+                */
+               offset_in_extent = em_start - em->start;
                em_end = extent_map_end(em);
+               em_len = em_end - em_start;
                emflags = em->flags;
                disko = 0;
                flags = 0;
 
+               /*
+                * bump off for our next call to get_extent
+                */
+               off = extent_map_end(em);
+               if (off >= max)
+                       end = 1;
+
                if (em->block_start == EXTENT_MAP_LAST_BYTE) {
                        end = 1;
                        flags |= FIEMAP_EXTENT_LAST;
@@ -3067,7 +3088,7 @@ int extent_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
                        flags |= (FIEMAP_EXTENT_DELALLOC |
                                  FIEMAP_EXTENT_UNKNOWN);
                } else {
-                       disko = em->block_start;
+                       disko = em->block_start + offset_in_extent;
                }
                if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags))
                        flags |= FIEMAP_EXTENT_ENCODED;