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authorLiu Bo <liubo2009@cn.fujitsu.com>2012-04-13 00:03:56 +0400
committerChris Mason <chris.mason@oracle.com>2012-04-13 00:03:56 +0400
commitb89203f74bdfcb15407d54d3f257b16a2ea19e62 (patch)
treea0cbfbc0bf259b4382b881a9108b21dc88525389 /fs
parentd95603b262edb53d6016a8df0c150371d4d61e67 (diff)
downloadlinux-b89203f74bdfcb15407d54d3f257b16a2ea19e62.tar.xz
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>
Diffstat (limited to 'fs')
-rw-r--r--fs/btrfs/volumes.c20
1 files changed, 18 insertions, 2 deletions
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index a872b48be0ae..759d02486d7c 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -3833,6 +3833,7 @@ static int __btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
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 @@ static int __btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
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 @@ static int __btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
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