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Mon, 29 Apr 2024 22:23:35 +0000 (UTC) Received: from dovecot-director2.suse.de ([10.150.64.162]) by imap1.dmz-prg2.suse.org with ESMTPSA id uIZvM+cdMGb2GQAAD6G6ig (envelope-from ) for ; Mon, 29 Apr 2024 22:23:35 +0000 From: Qu Wenruo To: linux-btrfs@vger.kernel.org Subject: [PATCH 5/9] btrfs: introduce extra sanity checks for extent maps Date: Tue, 30 Apr 2024 07:53:03 +0930 Message-ID: <36f97899fd2aa52fe6b042ef3d5e2a23f04fa9d2.1714428940.git.wqu@suse.com> X-Mailer: git-send-email 2.44.0 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-btrfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Spam-Level: X-Spamd-Result: default: False [-5.01 / 50.00]; BAYES_HAM(-3.00)[100.00%]; DWL_DNSWL_MED(-2.00)[suse.com:dkim]; MID_CONTAINS_FROM(1.00)[]; NEURAL_HAM_LONG(-1.00)[-1.000]; R_MISSING_CHARSET(0.50)[]; R_DKIM_ALLOW(-0.20)[suse.com:s=susede1]; NEURAL_HAM_SHORT(-0.20)[-1.000]; MIME_GOOD(-0.10)[text/plain]; MX_GOOD(-0.01)[]; RCVD_VIA_SMTP_AUTH(0.00)[]; ARC_NA(0.00)[]; RCPT_COUNT_ONE(0.00)[1]; TO_DN_NONE(0.00)[]; MIME_TRACE(0.00)[0:+]; FROM_HAS_DN(0.00)[]; FROM_EQ_ENVFROM(0.00)[]; FUZZY_BLOCKED(0.00)[rspamd.com]; DBL_BLOCKED_OPENRESOLVER(0.00)[suse.com:dkim,suse.com:email]; PREVIOUSLY_DELIVERED(0.00)[linux-btrfs@vger.kernel.org]; TO_MATCH_ENVRCPT_ALL(0.00)[]; RCVD_COUNT_TWO(0.00)[2]; DKIM_SIGNED(0.00)[suse.com:s=susede1]; RCVD_TLS_ALL(0.00)[]; DNSWL_BLOCKED(0.00)[2a07:de40:b281:104:10:150:64:97:from]; DKIM_TRACE(0.00)[suse.com:+] X-Rspamd-Action: no action X-Rspamd-Queue-Id: 46FBC1F788 X-Rspamd-Server: rspamd1.dmz-prg2.suse.org X-Spam-Flag: NO X-Spam-Score: -5.01 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 would 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: - Only compressed read/encoded write really utilize orig_start This can be proved by the cleanup patch of orig_start. - Merged data extents can lead to false alerts The problem is, with disk_bytenr/disk_num_bytes, if we're merging two extent maps like this: |<- data extent A -->|<-- data extent B -->| |<- em 1 ->|<- em 2 ->| Let's assume em2 has orig_offset of 0 and start of 0, and obvisouly offset 0. But after merging, the merged em would have offset of em1, screwing up whatever the @orig_start cross check against @start. The checks happens at the following timing: - 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() Since the check is way more strict than before, the following code has to be modified to pass the check: - extent-map-tests Previously the test case never populate ram_bytes, not to mention the newly introduced disk_bytenr/disk_num_bytes. Populate the involved numbers mostly to follow the existing block_start/block_len values. There are two special cases worth mentioning: - test_case_3() The test case is already way too invalid that tree-checker will reject almost all extents. And there is a special unaligned regular extent which has mismatch disk_num_bytes (4096) and ram_bytes (4096 - 1). Fix it by all assigned the disk_num_bytes and ram_bytes to 4096 - 1. - test_case_7() 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. - setup_relocation_extent_mapping() This is mostly utilized by relocation code to read the chunk like an inode. So populate the extent map using a regular non-compressed extent. In fact, the new cross checks already exposed a bug in btrfs_drop_extent_map_range(), and caught tons of bugs in the new members assignment. Signed-off-by: Qu Wenruo --- fs/btrfs/extent_map.c | 66 +++++++++++++++++++++++++++++++ fs/btrfs/relocation.c | 4 ++ fs/btrfs/tests/extent-map-tests.c | 56 +++++++++++++++++++++++++- fs/btrfs/tests/inode-tests.c | 2 +- 4 files changed, 126 insertions(+), 2 deletions(-) diff --git a/fs/btrfs/extent_map.c b/fs/btrfs/extent_map.c index 4d4ac9fc43e2..8d0e257fc113 100644 --- a/fs/btrfs/extent_map.c +++ b/fs/btrfs/extent_map.c @@ -284,6 +284,66 @@ static void merge_ondisk_extents(struct extent_map *prev, struct extent_map *nex next->offset = new_offset; } +static void dump_extent_map(const char *prefix, struct extent_map *em) +{ + if (!IS_ENABLED(CONFIG_BTRFS_DEBUG)) + return; + pr_crit("%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\n", + 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 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("zero disk_num_bytes", em); + if (em->offset + em->len > em->ram_bytes) + dump_extent_map("ram_bytes too small", em); + if (em->offset + em->len > em->disk_num_bytes && + !extent_map_is_compressed(em)) + dump_extent_map("disk_num_bytes too small", em); + + if (extent_map_is_compressed(em)) { + if (em->block_start != em->disk_bytenr) + dump_extent_map( + "mismatch block_start/disk_bytenr/offset", em); + if (em->disk_num_bytes != em->block_len) + dump_extent_map( + "mismatch disk_num_bytes/block_len", em); + /* + * Here we only check the start/orig_start/offset for + * compressed extents. + * This is because em::offset is always based on the + * referred data extent, which can be merged. + * + * In that case, @offset would no longer match + * em::start - em::orig_start, and cause false alert. + * + * Thankfully only compressed extent read/encoded write + * really bothers @orig_start, so we can skip + * the check for non-compressed extents. + */ + if (em->orig_start != em->start - em->offset) + dump_extent_map( + "mismatch orig_start/offset/start", em); + + } else { + if (em->block_start != em->disk_bytenr + em->offset) + dump_extent_map( + "mismatch block_start/disk_bytenr/offset", em); + } + } else { + if (em->offset) + dump_extent_map("non-zero offset for hole/inline", em); + } +} + static void try_merge_map(struct btrfs_inode *inode, struct extent_map *em) { struct extent_map_tree *tree = &inode->extent_tree; @@ -320,6 +380,7 @@ 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(em); rb_erase_cached(&merge->rb_node, &tree->map); RB_CLEAR_NODE(&merge->rb_node); free_extent_map(merge); @@ -335,6 +396,7 @@ 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(em); rb_erase_cached(&merge->rb_node, &tree->map); RB_CLEAR_NODE(&merge->rb_node); em->generation = max(em->generation, merge->generation); @@ -446,6 +508,7 @@ static int add_extent_mapping(struct btrfs_inode *inode, lockdep_assert_held_write(&tree->lock); + validate_extent_map(em); ret = tree_insert(&tree->map, em); if (ret) return ret; @@ -553,6 +616,9 @@ static void replace_extent_mapping(struct btrfs_inode *inode, lockdep_assert_held_write(&tree->lock); + validate_extent_map(cur); + validate_extent_map(new); + WARN_ON(cur->flags & EXTENT_FLAG_PINNED); ASSERT(extent_map_in_tree(cur)); if (!(cur->flags & EXTENT_FLAG_LOGGING)) diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c index 5cf5718c3b1f..277b03709537 100644 --- a/fs/btrfs/relocation.c +++ b/fs/btrfs/relocation.c @@ -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); diff --git a/fs/btrfs/tests/extent-map-tests.c b/fs/btrfs/tests/extent-map-tests.c index ba36794ba2d5..8c683eed9f27 100644 --- a/fs/btrfs/tests/extent-map-tests.c +++ b/fs/btrfs/tests/extent-map-tests.c @@ -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); diff --git a/fs/btrfs/tests/inode-tests.c b/fs/btrfs/tests/inode-tests.c index 99da9d34b77a..0895c6e06812 100644 --- a/fs/btrfs/tests/inode-tests.c +++ b/fs/btrfs/tests/inode-tests.c @@ -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;