[PATCH 09/21] Btrfs: fix divide error upon chunk's stripe_len

David Sterba
2016-06-03T15:43:06Z

From: Liu Bo <bo.li.liu@oracle.com>

commit 3d8da67817606380fdadfa483d4dba5c3a5446c6 upstream.

The struct 'map_lookup' uses type int for @stripe_len, while
btrfs_chunk_stripe_len() can return a u64 value, and it may end up with
@stripe_len being undefined value and it can lead to 'divide error' in
__btrfs_map_block().

This changes 'map_lookup' to use type u64 for stripe_len, also right now
we only use BTRFS_STRIPE_LEN for stripe_len, so this adds a valid checker for
BTRFS_STRIPE_LEN.

Reported-by: Vegard Nossum <vegard.nossum@oracle.com>
Reported-by: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ folded division fix to scrub_raid56_parity ]
Signed-off-by: David Sterba <dsterba@suse.com>
---
fs/btrfs/scrub.c | 2 +-
fs/btrfs/volumes.c | 2 +-
fs/btrfs/volumes.h | 2 +-
3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
index 92bf5ee732fb..160ac3e23270 100644
--- a/fs/btrfs/scrub.c
+++ b/fs/btrfs/scrub.c
@@ -2858,7 +2858,7 @@ static noinline_for_stack int scrub_raid56_parity(struct scrub_ctx *sctx,
int extent_mirror_num;
int stop_loop = 0;

- nsectors = map->stripe_len / root->sectorsize;
+ nsectors = div_u64(map->stripe_len, root->sectorsize);
bitmap_len = scrub_calc_parity_bitmap_len(nsectors);
sparity = kzalloc(sizeof(struct scrub_parity) + 2 * bitmap_len,
GFP_NOFS);
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 27a4f2e0856d..f4442fb6b8d4 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -6249,7 +6249,7 @@ static int read_one_chunk(struct btrfs_root *root, struct btrfs_key *key,
"invalid chunk length %llu", length);
return -EIO;
}
- if (!is_power_of_2(stripe_len)) {
+ if (!is_power_of_2(stripe_len) || stripe_len != BTRFS_STRIPE_LEN) {
btrfs_err(root->fs_info, "invalid chunk stripe length: %llu",
stripe_len);
return -EIO;
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index 1939ebde63df..7507be74f7da 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -347,7 +347,7 @@ struct map_lookup {
u64 type;
int io_align;
int io_width;
- int stripe_len;
+ u64 stripe_len;
int sector_size;
int num_stripes;
int sub_stripes;
--
2.7.1