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Diffstat (limited to 'fs/btrfs/extent_io.c')
-rw-r--r--fs/btrfs/extent_io.c33
1 files changed, 27 insertions, 6 deletions
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index ff45b80d90f..9fcb5ede6b7 100644
--- 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;