Patch "Btrfs: fix divide error upon chunk's stripe_len" has been added to the 4.5-stable tree

This is a note to let you know that I've just added the patch titled

Btrfs: fix divide error upon chunk's stripe_len

to the 4.5-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
btrfs-fix-divide-error-upon-chunk-s-stripe_len.patch
and it can be found in the queue-4.5 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Liu Bo <[email protected]>
Date: Tue, 26 Apr 2016 17:53:31 -0700
Subject: Btrfs: fix divide error upon chunk's stripe_len

From: Liu Bo <[email protected]>

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.

---
 fs/btrfs/scrub.c   |    2 +-
 fs/btrfs/volumes.c |    2 +-
 fs/btrfs/volumes.h |    2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

@@ -2858,7 +2858,7 @@ static noinline_for_stack int scrub_raid
 	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);

@@ -6249,7 +6249,7 @@ static int read_one_chunk(struct btrfs_r
 			"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;

@@ -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;

Patches currently in stable-queue which might be from [email protected] are

queue-4.5/btrfs-fix-unexpected-return-value-of-fiemap.patch queue-4.5/btrfs-do-not-create-empty-block-group-if-we-have-allocated-data.patch queue-4.5/btrfs-fix-divide-error-upon-chunk-s-stripe_len.patch