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Btrfs: fix free space tree bitmaps on big-endian systems

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In convert_free_space_to_{bitmaps,extents}(), we buffer the free space
bitmaps in memory and copy them directly to/from the extent buffers with
{read,write}_extent_buffer(). The extent buffer bitmap helpers use byte
granularity, which is equivalent to a little-endian bitmap. This means
that on big-endian systems, the in-memory bitmaps will be written to
disk byte-swapped. To fix this, use byte-granularity for the bitmaps in
memory.

Fixes: a5ed918285 ("Btrfs: implement the free space B-tree")
Cc: stable@vger.kernel.org # 4.5+
Tested-by: Holger Hoffstätte <holger@applied-asynchrony.com>
Tested-by: Chandan Rajendra <chandan@linux.vnet.ibm.com>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Omar Sandoval
2016-09-22 17:24:20 -07:00
committed by David Sterba
parent 08895a8b6b
commit 2fe1d55134
3 changed files with 76 additions and 27 deletions
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17
fs/btrfs/free-space-tree.c
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@@ -151,7 +151,7 @@ static inline u32 free_space_bitmap_size(u64 size, u32 sectorsize)
return DIV_ROUND_UP((u32)div_u64(size, sectorsize), BITS_PER_BYTE);
}
static unsigned long *alloc_bitmap(u32 bitmap_size)
static u8 *alloc_bitmap(u32 bitmap_size)
{
void *mem;
@@ -180,8 +180,7 @@ int convert_free_space_to_bitmaps(struct btrfs_trans_handle *trans,
struct btrfs_free_space_info *info;
struct btrfs_key key, found_key;
struct extent_buffer *leaf;
unsigned long *bitmap;
char *bitmap_cursor;
u8 *bitmap, *bitmap_cursor;
u64 start, end;
u64 bitmap_range, i;
u32 bitmap_size, flags, expected_extent_count;
@@ -231,7 +230,7 @@ int convert_free_space_to_bitmaps(struct btrfs_trans_handle *trans,
block_group->sectorsize);
last = div_u64(found_key.objectid + found_key.offset - start,
block_group->sectorsize);
bitmap_set(bitmap, first, last - first);
le_bitmap_set(bitmap, first, last - first);
extent_count++;
nr++;
@@ -269,7 +268,7 @@ int convert_free_space_to_bitmaps(struct btrfs_trans_handle *trans,
goto out;
}
bitmap_cursor = (char *)bitmap;
bitmap_cursor = bitmap;
bitmap_range = block_group->sectorsize * BTRFS_FREE_SPACE_BITMAP_BITS;
i = start;
while (i < end) {
@@ -318,7 +317,7 @@ int convert_free_space_to_extents(struct btrfs_trans_handle *trans,
struct btrfs_free_space_info *info;
struct btrfs_key key, found_key;
struct extent_buffer *leaf;
unsigned long *bitmap;
u8 *bitmap;
u64 start, end;
/* Initialize to silence GCC. */
u64 extent_start = 0;
@@ -362,7 +361,7 @@ int convert_free_space_to_extents(struct btrfs_trans_handle *trans,
break;
} else if (found_key.type == BTRFS_FREE_SPACE_BITMAP_KEY) {
unsigned long ptr;
char *bitmap_cursor;
u8 *bitmap_cursor;
u32 bitmap_pos, data_size;
ASSERT(found_key.objectid >= start);
@@ -372,7 +371,7 @@ int convert_free_space_to_extents(struct btrfs_trans_handle *trans,
bitmap_pos = div_u64(found_key.objectid - start,
block_group->sectorsize *
BITS_PER_BYTE);
bitmap_cursor = ((char *)bitmap) + bitmap_pos;
bitmap_cursor = bitmap + bitmap_pos;
data_size = free_space_bitmap_size(found_key.offset,
block_group->sectorsize);
@@ -409,7 +408,7 @@ int convert_free_space_to_extents(struct btrfs_trans_handle *trans,
offset = start;
bitnr = 0;
while (offset < end) {
bit = !!test_bit(bitnr, bitmap);
bit = !!le_test_bit(bitnr, bitmap);
if (prev_bit == 0 && bit == 1) {
extent_start = offset;
} else if (prev_bit == 1 && bit == 0) {