From b0d360b541f0455ee01215238d208c3710b43611 Mon Sep 17 00:00:00 2001 From: Lu Fengqi Date: Sat, 23 Apr 2016 15:26:25 +0800 Subject: [PATCH] btrfs-progs: check: introduce function to check data backref in extent tree Introduce a new function check_data_extent_item() to check if the corresponding data backref exists in extent tree. Signed-off-by: Lu Fengqi Signed-off-by: Qu Wenruo Reviewed-by: Josef Bacik Signed-off-by: David Sterba --- cmds-check.c | 156 ++++++++++++++++++++++++++++++++++++++++++++++++++ ctree.h | 2 + extent-tree.c | 2 +- 3 files changed, 159 insertions(+), 1 deletion(-) diff --git a/cmds-check.c b/cmds-check.c index 15a92a6a..84890f3d 100644 --- a/cmds-check.c +++ b/cmds-check.c @@ -442,6 +442,7 @@ struct root_item_info { */ #define BACKREF_MISSING (1 << 0) /* Backref missing in extent tree */ #define BACKREF_MISMATCH (1 << 1) /* Backref exists but does not match */ +#define BYTES_UNALIGNED (1 << 2) /* Some bytes are not aligned */ static void *print_status_check(void *p) { @@ -8704,6 +8705,161 @@ out: return err; } +/* + * Check EXTENT_DATA item, mainly for its dbackref in extent tree + * + * Return >0 any error found and output error message + * Return 0 for no error found + */ +static int check_extent_data_item(struct btrfs_root *root, + struct extent_buffer *eb, int slot) +{ + struct btrfs_file_extent_item *fi; + struct btrfs_path path; + struct btrfs_root *extent_root = root->fs_info->extent_root; + struct btrfs_key fi_key; + struct btrfs_key dbref_key; + struct extent_buffer *leaf; + struct btrfs_extent_item *ei; + struct btrfs_extent_inline_ref *iref; + struct btrfs_extent_data_ref *dref; + u64 owner; + u64 file_extent_gen; + u64 disk_bytenr; + u64 disk_num_bytes; + u64 extent_num_bytes; + u64 extent_flags; + u64 extent_gen; + u32 item_size; + unsigned long end; + unsigned long ptr; + int type; + u64 ref_root; + int found_dbackref = 0; + int err = 0; + int ret; + + btrfs_item_key_to_cpu(eb, &fi_key, slot); + fi = btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item); + file_extent_gen = btrfs_file_extent_generation(eb, fi); + + /* Nothing to check for hole and inline data extents */ + if (btrfs_file_extent_type(eb, fi) == BTRFS_FILE_EXTENT_INLINE || + btrfs_file_extent_disk_bytenr(eb, fi) == 0) + return 0; + + disk_bytenr = btrfs_file_extent_disk_bytenr(eb, fi); + disk_num_bytes = btrfs_file_extent_disk_num_bytes(eb, fi); + extent_num_bytes = btrfs_file_extent_num_bytes(eb, fi); + + /* Check unaligned disk_num_bytes and num_bytes */ + if (!IS_ALIGNED(disk_num_bytes, root->sectorsize)) { + error( +"file extent [%llu, %llu] has unaligned disk num bytes: %llu, should be aligned to %u", + fi_key.objectid, fi_key.offset, disk_num_bytes, + root->sectorsize); + err |= BYTES_UNALIGNED; + } else { + data_bytes_allocated += disk_num_bytes; + } + if (!IS_ALIGNED(extent_num_bytes, root->sectorsize)) { + error( +"file extent [%llu, %llu] has unaligned num bytes: %llu, should be aligned to %u", + fi_key.objectid, fi_key.offset, extent_num_bytes, + root->sectorsize); + err |= BYTES_UNALIGNED; + } else { + data_bytes_referenced += extent_num_bytes; + } + owner = btrfs_header_owner(eb); + + /* Check the extent item of the file extent in extent tree */ + btrfs_init_path(&path); + dbref_key.objectid = btrfs_file_extent_disk_bytenr(eb, fi); + dbref_key.type = BTRFS_EXTENT_ITEM_KEY; + dbref_key.offset = btrfs_file_extent_disk_num_bytes(eb, fi); + + ret = btrfs_search_slot(NULL, extent_root, &dbref_key, &path, 0, 0); + if (ret) { + err |= BACKREF_MISSING; + goto error; + } + + leaf = path.nodes[0]; + slot = path.slots[0]; + ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item); + + extent_flags = btrfs_extent_flags(leaf, ei); + extent_gen = btrfs_extent_generation(leaf, ei); + + if (!(extent_flags & BTRFS_EXTENT_FLAG_DATA)) { + error( + "extent[%llu %llu] backref type mismatch, wanted bit: %llx", + disk_bytenr, disk_num_bytes, + BTRFS_EXTENT_FLAG_DATA); + err |= BACKREF_MISMATCH; + } + + if (file_extent_gen < extent_gen) { + error( +"extent[%llu %llu] backref generation mismatch, wanted: <=%llu, have: %llu", + disk_bytenr, disk_num_bytes, file_extent_gen, + extent_gen); + err |= BACKREF_MISMATCH; + } + + /* Check data backref inside that extent item */ + item_size = btrfs_item_size_nr(leaf, path.slots[0]); + iref = (struct btrfs_extent_inline_ref *)(ei + 1); + ptr = (unsigned long)iref; + end = (unsigned long)ei + item_size; + while (ptr < end) { + iref = (struct btrfs_extent_inline_ref *)ptr; + type = btrfs_extent_inline_ref_type(leaf, iref); + dref = (struct btrfs_extent_data_ref *)(&iref->offset); + + if (type == BTRFS_EXTENT_DATA_REF_KEY) { + ref_root = btrfs_extent_data_ref_root(leaf, dref); + if (ref_root == owner || ref_root == root->objectid) + found_dbackref = 1; + } else if (type == BTRFS_SHARED_DATA_REF_KEY) { + found_dbackref = !check_tree_block_ref(root, NULL, + btrfs_extent_inline_ref_offset(leaf, iref), + 0, owner); + } + + if (found_dbackref) + break; + ptr += btrfs_extent_inline_ref_size(type); + } + + /* Didn't found inlined data backref, try EXTENT_DATA_REF_KEY */ + if (!found_dbackref) { + btrfs_release_path(&path); + + btrfs_init_path(&path); + dbref_key.objectid = btrfs_file_extent_disk_bytenr(eb, fi); + dbref_key.type = BTRFS_EXTENT_DATA_REF_KEY; + dbref_key.offset = hash_extent_data_ref(root->objectid, + fi_key.objectid, fi_key.offset); + + ret = btrfs_search_slot(NULL, root->fs_info->extent_root, + &dbref_key, &path, 0, 0); + if (!ret) + found_dbackref = 1; + } + + if (!found_dbackref) + err |= BACKREF_MISSING; +error: + btrfs_release_path(&path); + if (err & BACKREF_MISSING) { + error("data extent[%llu %llu] backref lost", + disk_bytenr, disk_num_bytes); + } + return err; +} + static int btrfs_fsck_reinit_root(struct btrfs_trans_handle *trans, struct btrfs_root *root, int overwrite) { diff --git a/ctree.h b/ctree.h index 5cb5533a..dda72d0e 100644 --- a/ctree.h +++ b/ctree.h @@ -2364,6 +2364,8 @@ int exclude_super_stripes(struct btrfs_root *root, struct btrfs_block_group_cache *cache); u64 add_new_free_space(struct btrfs_block_group_cache *block_group, struct btrfs_fs_info *info, u64 start, u64 end); +u64 hash_extent_data_ref(u64 root_objectid, u64 owner, u64 offset); + /* ctree.c */ int btrfs_comp_cpu_keys(struct btrfs_key *k1, struct btrfs_key *k2); int btrfs_del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root, diff --git a/extent-tree.c b/extent-tree.c index a58da237..6cc8d3f5 100644 --- a/extent-tree.c +++ b/extent-tree.c @@ -598,7 +598,7 @@ static int convert_extent_item_v0(struct btrfs_trans_handle *trans, } #endif -static u64 hash_extent_data_ref(u64 root_objectid, u64 owner, u64 offset) +u64 hash_extent_data_ref(u64 root_objectid, u64 owner, u64 offset) { u32 high_crc = ~(u32)0; u32 low_crc = ~(u32)0;