Btrfs: fix eof while discarding extents
We miscalculate the length of extents we're discarding, and it leads to
an eof of device.
Reported-by: Daniel Blueman <daniel@quora.org>
Signed-off-by: Liu Bo <liubo2009@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index a872b48..759d024 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -3833,6 +3833,7 @@
int sub_stripes = 0;
u64 stripes_per_dev = 0;
u32 remaining_stripes = 0;
+ u32 last_stripe = 0;
if (map->type &
(BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID10)) {
@@ -3846,6 +3847,8 @@
stripe_nr_orig,
factor,
&remaining_stripes);
+ div_u64_rem(stripe_nr_end - 1, factor, &last_stripe);
+ last_stripe *= sub_stripes;
}
for (i = 0; i < num_stripes; i++) {
@@ -3858,16 +3861,29 @@
BTRFS_BLOCK_GROUP_RAID10)) {
bbio->stripes[i].length = stripes_per_dev *
map->stripe_len;
+
if (i / sub_stripes < remaining_stripes)
bbio->stripes[i].length +=
map->stripe_len;
+
+ /*
+ * Special for the first stripe and
+ * the last stripe:
+ *
+ * |-------|...|-------|
+ * |----------|
+ * off end_off
+ */
if (i < sub_stripes)
bbio->stripes[i].length -=
stripe_offset;
- if ((i / sub_stripes + 1) %
- sub_stripes == remaining_stripes)
+
+ if (stripe_index >= last_stripe &&
+ stripe_index <= (last_stripe +
+ sub_stripes - 1))
bbio->stripes[i].length -=
stripe_end_offset;
+
if (i == sub_stripes - 1)
stripe_offset = 0;
} else