From 2fe1d55134fce05c17ea118a2e37a4af771887bc Mon Sep 17 00:00:00 2001 From: Omar Sandoval Date: Thu, 22 Sep 2016 17:24:20 -0700 Subject: Btrfs: fix free space tree bitmaps on big-endian systems MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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: a5ed91828518 ("Btrfs: implement the free space B-tree") Cc: stable@vger.kernel.org # 4.5+ Tested-by: Holger Hoffstätte Tested-by: Chandan Rajendra Signed-off-by: Omar Sandoval Signed-off-by: David Sterba --- fs/btrfs/free-space-tree.c | 17 ++++++++--------- 1 file changed, 8 insertions(+), 9 deletions(-) (limited to 'fs/btrfs/free-space-tree.c') diff --git a/fs/btrfs/free-space-tree.c b/fs/btrfs/free-space-tree.c index 87e7e3d3e676..8fd85bfbe2da 100644 --- a/fs/btrfs/free-space-tree.c +++ b/fs/btrfs/free-space-tree.c @@ -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) { -- cgit v1.2.3 From 6675df311db87aa2107a04ef97e19420953cbace Mon Sep 17 00:00:00 2001 From: Omar Sandoval Date: Thu, 22 Sep 2016 17:24:22 -0700 Subject: Btrfs: catch invalid free space trees MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit There are two separate issues that can lead to corrupted free space trees. 1. The free space tree bitmaps had an endianness issue on big-endian systems which is fixed by an earlier patch in this series. 2. btrfs-progs before v4.7.3 modified filesystems without updating the free space tree. To catch both of these issues at once, we need to force the free space tree to be rebuilt. To do so, add a FREE_SPACE_TREE_VALID compat_ro bit. If the bit isn't set, we know that it was either produced by a broken big-endian kernel or may have been corrupted by btrfs-progs. This also provides us with a way to add rudimentary read-write support for the free space tree to btrfs-progs: it can just clear this bit and have the kernel rebuild the free space tree. Cc: stable@vger.kernel.org # 4.5+ Tested-by: Holger Hoffstätte Tested-by: Chandan Rajendra Signed-off-by: Omar Sandoval Signed-off-by: David Sterba --- fs/btrfs/free-space-tree.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'fs/btrfs/free-space-tree.c') diff --git a/fs/btrfs/free-space-tree.c b/fs/btrfs/free-space-tree.c index 8fd85bfbe2da..ea605ffd0e03 100644 --- a/fs/btrfs/free-space-tree.c +++ b/fs/btrfs/free-space-tree.c @@ -1182,6 +1182,7 @@ int btrfs_create_free_space_tree(struct btrfs_fs_info *fs_info) } btrfs_set_fs_compat_ro(fs_info, FREE_SPACE_TREE); + btrfs_set_fs_compat_ro(fs_info, FREE_SPACE_TREE_VALID); fs_info->creating_free_space_tree = 0; ret = btrfs_commit_transaction(trans, tree_root); @@ -1250,6 +1251,7 @@ int btrfs_clear_free_space_tree(struct btrfs_fs_info *fs_info) return PTR_ERR(trans); btrfs_clear_fs_compat_ro(fs_info, FREE_SPACE_TREE); + btrfs_clear_fs_compat_ro(fs_info, FREE_SPACE_TREE_VALID); fs_info->free_space_root = NULL; ret = clear_free_space_tree(trans, free_space_root); -- cgit v1.2.3