btrfs: fix remaining u32 overflows when left shifting stripe_nr

There was regression caused by a97699d1d610 ("btrfs: replace
map_lookup->stripe_len by BTRFS_STRIPE_LEN") and supposedly fixed by
a7299a18a179 ("btrfs: fix u32 overflows when left shifting stripe_nr").
To avoid code churn the fix was open coding the type casts but
unfortunately missed one which was still possible to hit [1].

The missing place was assignment of bioc->full_stripe_logical inside
btrfs_map_block().

Fix it by adding a helper that does the safe calculation of the offset
and use it everywhere even though it may not be strictly necessary due
to already using u64 types.  This replaces all remaining
"<< BTRFS_STRIPE_LEN_SHIFT" calls.

[1] https://lore.kernel.org/linux-btrfs/20230622065438.86402-1-wqu@suse.com/

Fixes: a7299a18a179 ("btrfs: fix u32 overflows when left shifting stripe_nr")
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ update changelog ]
Signed-off-by: David Sterba <dsterba@suse.com>

1 files changed, 15 insertions, 14 deletions

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index e60beb14852a..72a838c97534 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -5125,7 +5125,7 @@ static void init_alloc_chunk_ctl_policy_regular(
 	/* We don't want a chunk larger than 10% of writable space */
 	ctl->max_chunk_size = min(mult_perc(fs_devices->total_rw_bytes, 10),
 				  ctl->max_chunk_size);
-	ctl->dev_extent_min = ctl->dev_stripes << BTRFS_STRIPE_LEN_SHIFT;
+	ctl->dev_extent_min = btrfs_stripe_nr_to_offset(ctl->dev_stripes);
 }
 
 static void init_alloc_chunk_ctl_policy_zoned(
@@ -5801,7 +5801,7 @@ unsigned long btrfs_full_stripe_len(struct btrfs_fs_info *fs_info,
 	if (!WARN_ON(IS_ERR(em))) {
 		map = em->map_lookup;
 		if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK)
-			len = nr_data_stripes(map) << BTRFS_STRIPE_LEN_SHIFT;
+			len = btrfs_stripe_nr_to_offset(nr_data_stripes(map));
 		free_extent_map(em);
 	}
 	return len;
@@ -5975,12 +5975,12 @@ struct btrfs_discard_stripe *btrfs_map_discard(struct btrfs_fs_info *fs_info,
 	stripe_nr = offset >> BTRFS_STRIPE_LEN_SHIFT;
 
 	/* stripe_offset is the offset of this block in its stripe */
-	stripe_offset = offset - ((u64)stripe_nr << BTRFS_STRIPE_LEN_SHIFT);
+	stripe_offset = offset - btrfs_stripe_nr_to_offset(stripe_nr);
 
 	stripe_nr_end = round_up(offset + length, BTRFS_STRIPE_LEN) >>
 			BTRFS_STRIPE_LEN_SHIFT;
 	stripe_cnt = stripe_nr_end - stripe_nr;
-	stripe_end_offset = ((u64)stripe_nr_end << BTRFS_STRIPE_LEN_SHIFT) -
+	stripe_end_offset = btrfs_stripe_nr_to_offset(stripe_nr_end) -
 			    (offset + length);
 	/*
 	 * after this, stripe_nr is the number of stripes on this
@@ -6023,12 +6023,12 @@ struct btrfs_discard_stripe *btrfs_map_discard(struct btrfs_fs_info *fs_info,
 	for (i = 0; i < *num_stripes; i++) {
 		stripes[i].physical =
 			map->stripes[stripe_index].physical +
-			stripe_offset + ((u64)stripe_nr << BTRFS_STRIPE_LEN_SHIFT);
+			stripe_offset + btrfs_stripe_nr_to_offset(stripe_nr);
 		stripes[i].dev = map->stripes[stripe_index].dev;
 
 		if (map->type & (BTRFS_BLOCK_GROUP_RAID0 |
 				 BTRFS_BLOCK_GROUP_RAID10)) {
-			stripes[i].length = stripes_per_dev << BTRFS_STRIPE_LEN_SHIFT;
+			stripes[i].length = btrfs_stripe_nr_to_offset(stripes_per_dev);
 
 			if (i / sub_stripes < remaining_stripes)
 				stripes[i].length += BTRFS_STRIPE_LEN;
@@ -6183,8 +6183,8 @@ static u64 btrfs_max_io_len(struct map_lookup *map, enum btrfs_map_op op,
 	ASSERT(*stripe_offset < U32_MAX);
 
 	if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
-		unsigned long full_stripe_len = nr_data_stripes(map) <<
-						BTRFS_STRIPE_LEN_SHIFT;
+		unsigned long full_stripe_len =
+			btrfs_stripe_nr_to_offset(nr_data_stripes(map));
 
 		/*
 		 * For full stripe start, we use previously calculated
@@ -6196,8 +6196,8 @@ static u64 btrfs_max_io_len(struct map_lookup *map, enum btrfs_map_op op,
 		 * not ensured to be power of 2.
 		 */
 		*full_stripe_start =
-			(u64)rounddown(*stripe_nr, nr_data_stripes(map)) <<
-			BTRFS_STRIPE_LEN_SHIFT;
+			btrfs_stripe_nr_to_offset(
+				rounddown(*stripe_nr, nr_data_stripes(map)));
 
 		ASSERT(*full_stripe_start + full_stripe_len > offset);
 		ASSERT(*full_stripe_start <= offset);
@@ -6223,7 +6223,7 @@ static void set_io_stripe(struct btrfs_io_stripe *dst, const struct map_lookup *
 {
 	dst->dev = map->stripes[stripe_index].dev;
 	dst->physical = map->stripes[stripe_index].physical +
-			stripe_offset + ((u64)stripe_nr << BTRFS_STRIPE_LEN_SHIFT);
+			stripe_offset + btrfs_stripe_nr_to_offset(stripe_nr);
 }
 
 int __btrfs_map_block(struct btrfs_fs_info *fs_info, enum btrfs_map_op op,
@@ -6345,7 +6345,8 @@ int __btrfs_map_block(struct btrfs_fs_info *fs_info, enum btrfs_map_op op,
 			/* Return the length to the full stripe end */
 			*length = min(logical + *length,
 				      raid56_full_stripe_start + em->start +
-				      (data_stripes << BTRFS_STRIPE_LEN_SHIFT)) - logical;
+				      btrfs_stripe_nr_to_offset(data_stripes)) -
+				  logical;
 			stripe_index = 0;
 			stripe_offset = 0;
 		} else {
@@ -6435,7 +6436,7 @@ int __btrfs_map_block(struct btrfs_fs_info *fs_info, enum btrfs_map_op op,
 		 * modulo, to reduce one modulo call.
 		 */
 		bioc->full_stripe_logical = em->start +
-			((stripe_nr * data_stripes) << BTRFS_STRIPE_LEN_SHIFT);
+			btrfs_stripe_nr_to_offset(stripe_nr * data_stripes);
 		for (i = 0; i < num_stripes; i++)
 			set_io_stripe(&bioc->stripes[i], map,
 				      (i + stripe_nr) % num_stripes,
@@ -8032,7 +8033,7 @@ static void map_raid56_repair_block(struct btrfs_io_context *bioc,
 
 	for (i = 0; i < data_stripes; i++) {
 		u64 stripe_start = bioc->full_stripe_logical +
-				   (i << BTRFS_STRIPE_LEN_SHIFT);
+				   btrfs_stripe_nr_to_offset(i);
 
 		if (logical >= stripe_start &&
 		    logical < stripe_start + BTRFS_STRIPE_LEN)