Commit 3f255ece authored by Qu Wenruo's avatar Qu Wenruo Committed by David Sterba
Browse files

btrfs: introduce extra sanity checks for extent maps 



Since extent_map structure has the all the needed members to represent a
file extent directly, we can apply all the file extent sanity checks to
an extent map.

The new sanity checks will cross check both the old members
(block_start/block_len/orig_start) and the new members
(disk_bytenr/disk_num_bytes/offset).

There is a special case for offset/orig_start/start cross check, we only
do such sanity check for compressed extent, as only compressed
read/encoded write really utilize orig_start.
This can be proved by the cleanup patch of orig_start.

The checks happens at the following times:

- add_extent_mapping()
  This is for newly added extent map

- replace_extent_mapping()
  This is for btrfs_drop_extent_map_range() and split_extent_map()

- try_merge_map()

For a lot of call sites we have to properly populate all the members to
pass the sanity check, meanwhile the following code needs extra
modification:

- setup_file_extents() from inode-tests
  The file extents layout of setup_file_extents() is already too invalid
  that tree-checker would reject most of them in real world.

  However there is just a special unaligned regular extent which has
  mismatched disk_num_bytes (4096) and ram_bytes (4096 - 1).
  So instead of dropping the whole test case, here we just unify
  disk_num_bytes and ram_bytes to 4096 - 1.

- test_case_7() from extent-map-tests
  An extent is inserted with 16K length, but on-disk extent size is
  only 4K.
  This means it must be a compressed extent, so set the compressed flag
  for it.

Reviewed-by: default avatarJohannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: default avatarFilipe Manana <fdmanana@suse.com>
Signed-off-by: default avatarQu Wenruo <wqu@suse.com>
Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 3d2ac992

fs/btrfs/extent_map.c

+59 −0
Original line number Diff line number Diff line
@@ -284,8 +284,61 @@ static void merge_ondisk_extents(struct extent_map *prev, struct extent_map *nex 
	next->offset = new_offset;

}



static void dump_extent_map(struct btrfs_fs_info *fs_info, const char *prefix,

			    struct extent_map *em)

{

	if (!IS_ENABLED(CONFIG_BTRFS_DEBUG))

		return;

	btrfs_crit(fs_info,

"%s, start=%llu len=%llu disk_bytenr=%llu disk_num_bytes=%llu ram_bytes=%llu offset=%llu orig_start=%llu block_start=%llu block_len=%llu flags=0x%x",

		prefix, em->start, em->len, em->disk_bytenr, em->disk_num_bytes,

		em->ram_bytes, em->offset, em->orig_start, em->block_start,

		em->block_len, em->flags);

	ASSERT(0);

}



/* Internal sanity checks for btrfs debug builds. */

static void validate_extent_map(struct btrfs_fs_info *fs_info, struct extent_map *em)

{

	if (!IS_ENABLED(CONFIG_BTRFS_DEBUG))

		return;

	if (em->disk_bytenr < EXTENT_MAP_LAST_BYTE) {

		if (em->disk_num_bytes == 0)

			dump_extent_map(fs_info, "zero disk_num_bytes", em);

		if (em->offset + em->len > em->ram_bytes)

			dump_extent_map(fs_info, "ram_bytes too small", em);

		if (em->offset + em->len > em->disk_num_bytes &&

		    !extent_map_is_compressed(em))

			dump_extent_map(fs_info, "disk_num_bytes too small", em);



		if (extent_map_is_compressed(em)) {

			if (em->block_start != em->disk_bytenr)

				dump_extent_map(fs_info,

					"mismatch block_start/disk_bytenr/offset", em);

			if (em->disk_num_bytes != em->block_len)

				dump_extent_map(fs_info,

					"mismatch disk_num_bytes/block_len", em);

			/*

			 * Here we only check the start/orig_start/offset for

			 * compressed extents as that's the only case where

			 * orig_start is utilized.

			 */

			if (em->orig_start != em->start - em->offset)

				dump_extent_map(fs_info,

					"mismatch orig_start/offset/start", em);



		} else if (em->block_start != em->disk_bytenr + em->offset) {

			dump_extent_map(fs_info,

				"mismatch block_start/disk_bytenr/offset", em);

		}

	} else if (em->offset) {

		dump_extent_map(fs_info, "non-zero offset for hole/inline", em);

	}

}



static void try_merge_map(struct btrfs_inode *inode, struct extent_map *em)

{

	struct btrfs_fs_info *fs_info = inode->root->fs_info;

	struct extent_map_tree *tree = &inode->extent_tree;

	struct extent_map *merge = NULL;

	struct rb_node *rb;
@@ -320,6 +373,7 @@ static void try_merge_map(struct btrfs_inode *inode, struct extent_map *em) 
				merge_ondisk_extents(merge, em);

			em->flags |= EXTENT_FLAG_MERGED;



			validate_extent_map(fs_info, em);

			rb_erase(&merge->rb_node, &tree->root);

			RB_CLEAR_NODE(&merge->rb_node);

			free_extent_map(merge);
@@ -335,6 +389,7 @@ static void try_merge_map(struct btrfs_inode *inode, struct extent_map *em) 
		em->block_len += merge->block_len;

		if (em->disk_bytenr < EXTENT_MAP_LAST_BYTE)

			merge_ondisk_extents(em, merge);

		validate_extent_map(fs_info, em);

		rb_erase(&merge->rb_node, &tree->root);

		RB_CLEAR_NODE(&merge->rb_node);

		em->generation = max(em->generation, merge->generation);
@@ -446,6 +501,7 @@ static int add_extent_mapping(struct btrfs_inode *inode, 


	lockdep_assert_held_write(&tree->lock);



	validate_extent_map(fs_info, em);

	ret = tree_insert(&tree->root, em);

	if (ret)

		return ret;
@@ -549,10 +605,13 @@ static void replace_extent_mapping(struct btrfs_inode *inode, 
				   struct extent_map *new,

				   int modified)

{

	struct btrfs_fs_info *fs_info = inode->root->fs_info;

	struct extent_map_tree *tree = &inode->extent_tree;



	lockdep_assert_held_write(&tree->lock);



	validate_extent_map(fs_info, new);



	WARN_ON(cur->flags & EXTENT_FLAG_PINNED);

	ASSERT(extent_map_in_tree(cur));

	if (!(cur->flags & EXTENT_FLAG_LOGGING))

fs/btrfs/relocation.c

+4 −0
Original line number Diff line number Diff line
@@ -2911,9 +2911,13 @@ static noinline_for_stack int setup_relocation_extent_mapping(struct inode *inod 
		return -ENOMEM;



	em->start = start;

	em->orig_start = start;

	em->len = end + 1 - start;

	em->block_len = em->len;

	em->block_start = block_start;

	em->disk_bytenr = block_start;

	em->disk_num_bytes = em->len;

	em->ram_bytes = em->len;

	em->flags |= EXTENT_FLAG_PINNED;



	lock_extent(&BTRFS_I(inode)->io_tree, start, end, &cached_state);

fs/btrfs/tests/extent-map-tests.c

+55 −1
Original line number Diff line number Diff line
@@ -78,6 +78,9 @@ static int test_case_1(struct btrfs_fs_info *fs_info, struct btrfs_inode *inode) 
	em->len = SZ_16K;

	em->block_start = 0;

	em->block_len = SZ_16K;

	em->disk_bytenr = 0;

	em->disk_num_bytes = SZ_16K;

	em->ram_bytes = SZ_16K;

	write_lock(&em_tree->lock);

	ret = btrfs_add_extent_mapping(inode, &em, em->start, em->len);

	write_unlock(&em_tree->lock);
@@ -96,9 +99,13 @@ static int test_case_1(struct btrfs_fs_info *fs_info, struct btrfs_inode *inode) 
	}



	em->start = SZ_16K;

	em->orig_start = SZ_16K;

	em->len = SZ_4K;

	em->block_start = SZ_32K; /* avoid merging */

	em->block_len = SZ_4K;

	em->disk_bytenr = SZ_32K; /* avoid merging */

	em->disk_num_bytes = SZ_4K;

	em->ram_bytes = SZ_4K;

	write_lock(&em_tree->lock);

	ret = btrfs_add_extent_mapping(inode, &em, em->start, em->len);

	write_unlock(&em_tree->lock);
@@ -117,9 +124,13 @@ static int test_case_1(struct btrfs_fs_info *fs_info, struct btrfs_inode *inode) 


	/* Add [0, 8K), should return [0, 16K) instead. */

	em->start = start;

	em->orig_start = start;

	em->len = len;

	em->block_start = start;

	em->block_len = len;

	em->disk_bytenr = start;

	em->disk_num_bytes = len;

	em->ram_bytes = len;

	write_lock(&em_tree->lock);

	ret = btrfs_add_extent_mapping(inode, &em, em->start, em->len);

	write_unlock(&em_tree->lock);
@@ -174,6 +185,9 @@ static int test_case_2(struct btrfs_fs_info *fs_info, struct btrfs_inode *inode) 
	em->len = SZ_1K;

	em->block_start = EXTENT_MAP_INLINE;

	em->block_len = (u64)-1;

	em->disk_bytenr = EXTENT_MAP_INLINE;

	em->disk_num_bytes = 0;

	em->ram_bytes = SZ_1K;

	write_lock(&em_tree->lock);

	ret = btrfs_add_extent_mapping(inode, &em, em->start, em->len);

	write_unlock(&em_tree->lock);
@@ -192,9 +206,13 @@ static int test_case_2(struct btrfs_fs_info *fs_info, struct btrfs_inode *inode) 
	}



	em->start = SZ_4K;

	em->orig_start = SZ_4K;

	em->len = SZ_4K;

	em->block_start = SZ_4K;

	em->block_len = SZ_4K;

	em->disk_bytenr = SZ_4K;

	em->disk_num_bytes = SZ_4K;

	em->ram_bytes = SZ_4K;

	write_lock(&em_tree->lock);

	ret = btrfs_add_extent_mapping(inode, &em, em->start, em->len);

	write_unlock(&em_tree->lock);
@@ -216,6 +234,9 @@ static int test_case_2(struct btrfs_fs_info *fs_info, struct btrfs_inode *inode) 
	em->len = SZ_1K;

	em->block_start = EXTENT_MAP_INLINE;

	em->block_len = (u64)-1;

	em->disk_bytenr = EXTENT_MAP_INLINE;

	em->disk_num_bytes = 0;

	em->ram_bytes = SZ_1K;

	write_lock(&em_tree->lock);

	ret = btrfs_add_extent_mapping(inode, &em, em->start, em->len);

	write_unlock(&em_tree->lock);
@@ -262,9 +283,13 @@ static int __test_case_3(struct btrfs_fs_info *fs_info, 


	/* Add [4K, 8K) */

	em->start = SZ_4K;

	em->orig_start = SZ_4K;

	em->len = SZ_4K;

	em->block_start = SZ_4K;

	em->block_len = SZ_4K;

	em->disk_bytenr = SZ_4K;

	em->disk_num_bytes = SZ_4K;

	em->ram_bytes = SZ_4K;

	write_lock(&em_tree->lock);

	ret = btrfs_add_extent_mapping(inode, &em, em->start, em->len);

	write_unlock(&em_tree->lock);
@@ -286,6 +311,9 @@ static int __test_case_3(struct btrfs_fs_info *fs_info, 
	em->len = SZ_16K;

	em->block_start = 0;

	em->block_len = SZ_16K;

	em->disk_bytenr = 0;

	em->disk_num_bytes = SZ_16K;

	em->ram_bytes = SZ_16K;

	write_lock(&em_tree->lock);

	ret = btrfs_add_extent_mapping(inode, &em, start, len);

	write_unlock(&em_tree->lock);
@@ -372,6 +400,9 @@ static int __test_case_4(struct btrfs_fs_info *fs_info, 
	em->len = SZ_8K;

	em->block_start = 0;

	em->block_len = SZ_8K;

	em->disk_bytenr = 0;

	em->disk_num_bytes = SZ_8K;

	em->ram_bytes = SZ_8K;

	write_lock(&em_tree->lock);

	ret = btrfs_add_extent_mapping(inode, &em, em->start, em->len);

	write_unlock(&em_tree->lock);
@@ -390,9 +421,13 @@ static int __test_case_4(struct btrfs_fs_info *fs_info, 


	/* Add [8K, 32K) */

	em->start = SZ_8K;

	em->orig_start = SZ_8K;

	em->len = 24 * SZ_1K;

	em->block_start = SZ_16K; /* avoid merging */

	em->block_len = 24 * SZ_1K;

	em->disk_bytenr = SZ_16K; /* avoid merging */

	em->disk_num_bytes = 24 * SZ_1K;

	em->ram_bytes = 24 * SZ_1K;

	write_lock(&em_tree->lock);

	ret = btrfs_add_extent_mapping(inode, &em, em->start, em->len);

	write_unlock(&em_tree->lock);
@@ -410,9 +445,13 @@ static int __test_case_4(struct btrfs_fs_info *fs_info, 
	}

	/* Add [0K, 32K) */

	em->start = 0;

	em->orig_start = 0;

	em->len = SZ_32K;

	em->block_start = 0;

	em->block_len = SZ_32K;

	em->disk_bytenr = 0;

	em->disk_num_bytes = SZ_32K;

	em->ram_bytes = SZ_32K;

	write_lock(&em_tree->lock);

	ret = btrfs_add_extent_mapping(inode, &em, start, len);

	write_unlock(&em_tree->lock);
@@ -494,9 +533,13 @@ static int add_compressed_extent(struct btrfs_inode *inode, 
	}



	em->start = start;

	em->orig_start = start;

	em->len = len;

	em->block_start = block_start;

	em->block_len = SZ_4K;

	em->disk_bytenr = block_start;

	em->disk_num_bytes = SZ_4K;

	em->ram_bytes = len;

	em->flags |= EXTENT_FLAG_COMPRESS_ZLIB;

	write_lock(&em_tree->lock);

	ret = btrfs_add_extent_mapping(inode, &em, em->start, em->len);
@@ -715,9 +758,13 @@ static int test_case_6(struct btrfs_fs_info *fs_info, struct btrfs_inode *inode) 
	}



	em->start = SZ_4K;

	em->orig_start = SZ_4K;

	em->len = SZ_4K;

	em->block_start = SZ_16K;

	em->block_len = SZ_16K;

	em->disk_bytenr = SZ_16K;

	em->disk_num_bytes = SZ_16K;

	em->ram_bytes = SZ_16K;

	write_lock(&em_tree->lock);

	ret = btrfs_add_extent_mapping(inode, &em, 0, SZ_8K);

	write_unlock(&em_tree->lock);
@@ -771,7 +818,10 @@ static int test_case_7(struct btrfs_fs_info *fs_info, struct btrfs_inode *inode) 
	em->len = SZ_16K;

	em->block_start = 0;

	em->block_len = SZ_4K;

	em->flags |= EXTENT_FLAG_PINNED;

	em->disk_bytenr = 0;

	em->disk_num_bytes = SZ_4K;

	em->ram_bytes = SZ_16K;

	em->flags |= (EXTENT_FLAG_PINNED | EXTENT_FLAG_COMPRESS_ZLIB);

	write_lock(&em_tree->lock);

	ret = btrfs_add_extent_mapping(inode, &em, em->start, em->len);

	write_unlock(&em_tree->lock);
@@ -790,9 +840,13 @@ static int test_case_7(struct btrfs_fs_info *fs_info, struct btrfs_inode *inode) 


	/* [32K, 48K), not pinned */

	em->start = SZ_32K;

	em->orig_start = SZ_32K;

	em->len = SZ_16K;

	em->block_start = SZ_32K;

	em->block_len = SZ_16K;

	em->disk_bytenr = SZ_32K;

	em->disk_num_bytes = SZ_16K;

	em->ram_bytes = SZ_16K;

	write_lock(&em_tree->lock);

	ret = btrfs_add_extent_mapping(inode, &em, em->start, em->len);

	write_unlock(&em_tree->lock);

fs/btrfs/tests/inode-tests.c

+1 −1
Original line number Diff line number Diff line
@@ -117,7 +117,7 @@ static void setup_file_extents(struct btrfs_root *root, u32 sectorsize) 


	/* Now for a regular extent */

	insert_extent(root, offset, sectorsize - 1, sectorsize - 1, 0,

		      disk_bytenr, sectorsize, BTRFS_FILE_EXTENT_REG, 0, slot);

		      disk_bytenr, sectorsize - 1, BTRFS_FILE_EXTENT_REG, 0, slot);

	slot++;

	disk_bytenr += sectorsize;

	offset += sectorsize - 1;