From 6f3cf25a4e7932bc737ed06bc95f73f80772092d Mon Sep 17 00:00:00 2001 From: "Yan, Zheng" Date: Mon, 21 Sep 2009 16:03:57 -0400 Subject: [PATCH] btrfsck: check root back/forward references This patch adds semantic checks for links to snapshot/subvolume and root back/forward references. Signed-off-by: Yan Zheng Signed-off-by: Chris Mason --- btrfsck.c | 444 +++++++++++++++++++++++++++++++++++++++++++++++++----- 1 file changed, 410 insertions(+), 34 deletions(-) diff --git a/btrfsck.c b/btrfsck.c index 40c90f81..73f1836e 100644 --- a/btrfsck.c +++ b/btrfsck.c @@ -36,7 +36,7 @@ static u64 total_fs_tree_bytes = 0; static u64 btree_space_waste = 0; static u64 data_bytes_allocated = 0; static u64 data_bytes_referenced = 0; -int found_old_backref = 0; +static int found_old_backref = 0; struct extent_backref { struct list_head list; @@ -100,7 +100,11 @@ struct inode_backref { #define REF_ERR_DUP_INODE_REF (1 << 5) #define REF_ERR_INDEX_UNMATCH (1 << 6) #define REF_ERR_FILETYPE_UNMATCH (1 << 7) -#define REF_ERR_NAME_TOO_LONG (1 << 8) +#define REF_ERR_NAME_TOO_LONG (1 << 8) // 100 +#define REF_ERR_NO_ROOT_REF (1 << 9) +#define REF_ERR_NO_ROOT_BACKREF (1 << 10) +#define REF_ERR_DUP_ROOT_REF (1 << 11) +#define REF_ERR_DUP_ROOT_BACKREF (1 << 12) struct inode_record { struct list_head backrefs; @@ -144,6 +148,29 @@ struct inode_record { #define I_ERR_SOME_CSUM_MISSING (1 << 12) #define I_ERR_LINK_COUNT_WRONG (1 << 13) +struct root_backref { + struct list_head list; + unsigned int found_dir_item:1; + unsigned int found_dir_index:1; + unsigned int found_back_ref:1; + unsigned int found_forward_ref:1; + unsigned int reachable:1; + int errors; + u64 ref_root; + u64 dir; + u64 index; + u16 namelen; + char name[0]; +}; + +struct root_record { + struct list_head backrefs; + struct cache_extent cache; + unsigned int found_root_item:1; + u64 objectid; + u32 found_ref; +}; + struct ptr_node { struct cache_extent cache; void *data; @@ -151,6 +178,7 @@ struct ptr_node { struct shared_node { struct cache_extent cache; + struct cache_tree root_cache; struct cache_tree inode_cache; struct inode_record *current; u32 refs; @@ -258,6 +286,14 @@ static void free_inode_rec(struct inode_record *rec) free(rec); } +static int can_free_inode_rec(struct inode_record *rec) +{ + if (!rec->errors && rec->checked && rec->found_inode_item && + rec->nlink == rec->found_link && list_empty(&rec->backrefs)) + return 1; + return 0; +} + static void maybe_free_inode_rec(struct cache_tree *inode_cache, struct inode_record *rec) { @@ -309,8 +345,7 @@ static void maybe_free_inode_rec(struct cache_tree *inode_cache, } BUG_ON(rec->refs != 1); - if (!rec->errors && rec->nlink == rec->found_link && - list_empty(&rec->backrefs)) { + if (can_free_inode_rec(rec)) { cache = find_cache_extent(inode_cache, rec->ino, 1); node = container_of(cache, struct ptr_node, cache); BUG_ON(node->data != rec); @@ -338,14 +373,12 @@ static int check_orphan_item(struct btrfs_root *root, u64 ino) return ret; } -static int process_inode_item(struct btrfs_root *root, - struct extent_buffer *eb, +static int process_inode_item(struct extent_buffer *eb, int slot, struct btrfs_key *key, struct shared_node *active_node) { struct inode_record *rec; struct btrfs_inode_item *item; - int ret; rec = active_node->current; BUG_ON(rec->ino != key->objectid || rec->refs > 1); @@ -361,11 +394,8 @@ static int process_inode_item(struct btrfs_root *root, if (btrfs_inode_flags(eb, item) & BTRFS_INODE_NODATASUM) rec->nodatasum = 1; rec->found_inode_item = 1; - if (rec->nlink == 0) { - ret = check_orphan_item(root, rec->ino); - if (ret == -ENOENT) - rec->errors |= I_ERR_NO_ORPHAN_ITEM; - } + if (rec->nlink == 0) + rec->errors |= I_ERR_NO_ORPHAN_ITEM; maybe_free_inode_rec(&active_node->inode_cache, rec); return 0; } @@ -443,10 +473,9 @@ static int add_inode_backref(struct cache_tree *inode_cache, } static int merge_inode_recs(struct inode_record *src, struct inode_record *dst, - struct shared_node *dst_node) + struct cache_tree *dst_cache) { struct inode_backref *backref; - struct cache_tree *dst_cache = &dst_node->inode_cache; dst->merging = 1; list_for_each_entry(backref, &src->backrefs, list) { @@ -510,14 +539,8 @@ static int merge_inode_recs(struct inode_record *src, struct inode_record *dst, dst->errors |= I_ERR_DUP_INODE_ITEM; } } - - if (src->checked) { - dst->checked = 1; - if (dst_node->current == dst) - dst_node->current = NULL; - } dst->merging = 0; - maybe_free_inode_rec(dst_cache, dst); + return 0; } @@ -537,8 +560,9 @@ static int splice_shared_node(struct shared_node *src_node, if (src_node->current) current_ino = src_node->current->ino; - src = &src_node->inode_cache; - dst = &dst_node->inode_cache; + src = &src_node->root_cache; + dst = &dst_node->root_cache; +again: cache = find_first_cache_extent(src, 0); while (cache) { node = container_of(cache, struct ptr_node, cache); @@ -557,14 +581,28 @@ static int splice_shared_node(struct shared_node *src_node, } ret = insert_existing_cache_extent(dst, &ins->cache); if (ret == -EEXIST) { + WARN_ON(src == &src_node->root_cache); conflict = get_inode_rec(dst, rec->ino, 1); - merge_inode_recs(rec, conflict, dst_node); + merge_inode_recs(rec, conflict, dst); + if (rec->checked) { + conflict->checked = 1; + if (dst_node->current == conflict) + dst_node->current = NULL; + } + maybe_free_inode_rec(dst, conflict); free_inode_rec(rec); free(ins); } else { BUG_ON(ret); } } + + if (src == &src_node->root_cache) { + src = &src_node->inode_cache; + dst = &dst_node->inode_cache; + goto again; + } + if (current_ino > 0 && (!dst_node->current || current_ino > dst_node->current->ino)) { if (dst_node->current) { @@ -616,6 +654,7 @@ static int add_shared_node(struct cache_tree *shared, u64 bytenr, u32 refs) node = calloc(1, sizeof(*node)); node->cache.start = bytenr; node->cache.size = 1; + cache_tree_init(&node->root_cache); cache_tree_init(&node->inode_cache); node->refs = refs; @@ -646,6 +685,7 @@ static int enter_shared_node(struct btrfs_root *root, u64 bytenr, u32 refs, if (wc->root_level == wc->active_node && btrfs_root_refs(&root->root_item) == 0) { if (--node->refs == 0) { + free_inode_recs(&node->root_cache); free_inode_recs(&node->inode_cache); remove_cache_extent(&wc->shared, &node->cache); free(node); @@ -708,10 +748,12 @@ static int process_dir_item(struct extent_buffer *eb, int filetype; struct btrfs_dir_item *di; struct inode_record *rec; + struct cache_tree *root_cache; struct cache_tree *inode_cache; struct btrfs_key location; char namebuf[BTRFS_NAME_LEN]; + root_cache = &active_node->root_cache; inode_cache = &active_node->inode_cache; rec = active_node->current; rec->found_dir_item = 1; @@ -740,7 +782,9 @@ static int process_dir_item(struct extent_buffer *eb, key->objectid, key->offset, namebuf, len, filetype, key->type, error); } else if (location.type == BTRFS_ROOT_ITEM_KEY) { - /* fixme: check root back & forward references */ + add_inode_backref(root_cache, location.objectid, + key->objectid, key->offset, namebuf, + len, filetype, key->type, error); } else { fprintf(stderr, "warning line %d\n", __LINE__); } @@ -977,8 +1021,7 @@ static int process_one_leaf(struct btrfs_root *root, struct extent_buffer *eb, ret = process_inode_ref(eb, i, &key, active_node); break; case BTRFS_INODE_ITEM_KEY: - ret = process_inode_item(root, eb, i, &key, - active_node); + ret = process_inode_item(eb, i, &key, active_node); break; case BTRFS_EXTENT_DATA_KEY: ret = process_file_extent(root, eb, i, &key, @@ -1176,13 +1219,23 @@ static int check_inode_recs(struct btrfs_root *root, node = container_of(cache, struct ptr_node, cache); rec = node->data; remove_cache_extent(inode_cache, &node->cache); + free(node); if (rec->ino == root_dirid || rec->ino == BTRFS_ORPHAN_OBJECTID) { - free(node); free_inode_rec(rec); continue; } + if (rec->errors & I_ERR_NO_ORPHAN_ITEM) { + ret = check_orphan_item(root, rec->ino); + if (ret == 0) + rec->errors &= ~I_ERR_NO_ORPHAN_ITEM; + if (can_free_inode_rec(rec)) { + free_inode_rec(rec); + continue; + } + } + error++; if (!rec->found_inode_item) rec->errors |= I_ERR_NO_INODE_ITEM; @@ -1205,13 +1258,314 @@ static int check_inode_recs(struct btrfs_root *root, backref->namelen, backref->name, backref->filetype, backref->errors); } - free(node); free_inode_rec(rec); } return (error > 0) ? -1 : 0; } +static struct root_record *get_root_rec(struct cache_tree *root_cache, + u64 objectid) +{ + struct cache_extent *cache; + struct root_record *rec = NULL; + int ret; + + cache = find_cache_extent(root_cache, objectid, 1); + if (cache) { + rec = container_of(cache, struct root_record, cache); + } else { + rec = calloc(1, sizeof(*rec)); + rec->objectid = objectid; + INIT_LIST_HEAD(&rec->backrefs); + rec->cache.start = objectid; + rec->cache.size = 1; + + ret = insert_existing_cache_extent(root_cache, &rec->cache); + BUG_ON(ret); + } + return rec; +} + +static struct root_backref *get_root_backref(struct root_record *rec, + u64 ref_root, u64 dir, u64 index, + const char *name, int namelen) +{ + struct root_backref *backref; + + list_for_each_entry(backref, &rec->backrefs, list) { + if (backref->ref_root != ref_root || backref->dir != dir || + backref->namelen != namelen) + continue; + if (memcmp(name, backref->name, namelen)) + continue; + return backref; + } + + backref = malloc(sizeof(*backref) + namelen + 1); + memset(backref, 0, sizeof(*backref)); + backref->ref_root = ref_root; + backref->dir = dir; + backref->index = index; + backref->namelen = namelen; + memcpy(backref->name, name, namelen); + backref->name[namelen] = '\0'; + list_add_tail(&backref->list, &rec->backrefs); + return backref; +} + +static void free_root_recs(struct cache_tree *root_cache) +{ + struct cache_extent *cache; + struct root_record *rec; + struct root_backref *backref; + + while (1) { + cache = find_first_cache_extent(root_cache, 0); + if (!cache) + break; + rec = container_of(cache, struct root_record, cache); + remove_cache_extent(root_cache, &rec->cache); + + while (!list_empty(&rec->backrefs)) { + backref = list_entry(rec->backrefs.next, + struct root_backref, list); + list_del(&backref->list); + free(backref); + } + kfree(rec); + } +} + +static int add_root_backref(struct cache_tree *root_cache, + u64 root_id, u64 ref_root, u64 dir, u64 index, + const char *name, int namelen, + int item_type, int errors) +{ + struct root_record *rec; + struct root_backref *backref; + + rec = get_root_rec(root_cache, root_id); + backref = get_root_backref(rec, ref_root, dir, index, name, namelen); + + backref->errors |= errors; + + if (item_type != BTRFS_DIR_ITEM_KEY) { + if (backref->found_dir_index || backref->found_back_ref || + backref->found_forward_ref) { + if (backref->index != index) + backref->errors |= REF_ERR_INDEX_UNMATCH; + } else { + backref->index = index; + } + } + + if (item_type == BTRFS_DIR_ITEM_KEY) { + backref->found_dir_item = 1; + backref->reachable = 1; + rec->found_ref++; + } else if (item_type == BTRFS_DIR_INDEX_KEY) { + backref->found_dir_index = 1; + } else if (item_type == BTRFS_ROOT_REF_KEY) { + if (backref->found_forward_ref) + backref->errors |= REF_ERR_DUP_ROOT_REF; + backref->found_forward_ref = 1; + } else if (item_type == BTRFS_ROOT_BACKREF_KEY) { + if (backref->found_back_ref) + backref->errors |= REF_ERR_DUP_ROOT_BACKREF; + backref->found_back_ref = 1; + } else { + BUG_ON(1); + } + + return 0; +} + +static int merge_root_recs(struct btrfs_root *root, + struct cache_tree *src_cache, + struct cache_tree *dst_cache) +{ + struct cache_extent *cache; + struct ptr_node *node; + struct inode_record *rec; + struct inode_backref *backref; + + if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) { + free_inode_recs(src_cache); + return 0; + } + + while (1) { + cache = find_first_cache_extent(src_cache, 0); + if (!cache) + break; + node = container_of(cache, struct ptr_node, cache); + rec = node->data; + remove_cache_extent(src_cache, &node->cache); + free(node); + + list_for_each_entry(backref, &rec->backrefs, list) { + BUG_ON(backref->found_inode_ref); + if (backref->found_dir_item) + add_root_backref(dst_cache, rec->ino, + root->root_key.objectid, backref->dir, + backref->index, backref->name, + backref->namelen, BTRFS_DIR_ITEM_KEY, + backref->errors); + if (backref->found_dir_index) + add_root_backref(dst_cache, rec->ino, + root->root_key.objectid, backref->dir, + backref->index, backref->name, + backref->namelen, BTRFS_DIR_INDEX_KEY, + backref->errors); + } + free_inode_rec(rec); + } + return 0; +} + +static int check_root_refs(struct btrfs_root *root, + struct cache_tree *root_cache) +{ + struct root_record *rec; + struct root_record *ref_root; + struct root_backref *backref; + struct cache_extent *cache; + int loop = 1; + int ret; + int error; + int errors = 0; + + rec = get_root_rec(root_cache, BTRFS_FS_TREE_OBJECTID); + rec->found_ref = 1; + + /* fixme: this can not detect circular references */ + while (loop) { + loop = 0; + cache = find_first_cache_extent(root_cache, 0); + while (1) { + if (!cache) + break; + rec = container_of(cache, struct root_record, cache); + cache = next_cache_extent(cache); + + if (rec->found_ref == 0) + continue; + + list_for_each_entry(backref, &rec->backrefs, list) { + if (!backref->reachable) + continue; + + ref_root = get_root_rec(root_cache, + backref->ref_root); + if (ref_root->found_ref > 0) + continue; + + backref->reachable = 0; + rec->found_ref--; + if (rec->found_ref == 0) + loop = 1; + } + } + } + + cache = find_first_cache_extent(root_cache, 0); + while (1) { + if (!cache) + break; + rec = container_of(cache, struct root_record, cache); + cache = next_cache_extent(cache); + + if (rec->found_ref == 0 && + rec->objectid >= BTRFS_FIRST_FREE_OBJECTID && + rec->objectid <= BTRFS_LAST_FREE_OBJECTID) { + ret = check_orphan_item(root->fs_info->tree_root, + rec->objectid); + if (ret == 0) + continue; + errors++; + fprintf(stderr, "fs tree %llu not referenced\n", + (unsigned long long)rec->objectid); + } + + error = 0; + if (rec->found_ref > 0 && !rec->found_root_item) + error = 1; + list_for_each_entry(backref, &rec->backrefs, list) { + if (!backref->found_dir_item) + backref->errors |= REF_ERR_NO_DIR_ITEM; + if (!backref->found_dir_index) + backref->errors |= REF_ERR_NO_DIR_INDEX; + if (!backref->found_back_ref) + backref->errors |= REF_ERR_NO_ROOT_BACKREF; + if (!backref->found_forward_ref) + backref->errors |= REF_ERR_NO_ROOT_REF; + if (backref->reachable && backref->errors) + error = 1; + } + if (!error) + continue; + + errors++; + fprintf(stderr, "fs tree %llu refs %u %s\n", + (unsigned long long)rec->objectid, rec->found_ref, + rec->found_root_item ? "" : "not found"); + + list_for_each_entry(backref, &rec->backrefs, list) { + if (!backref->reachable) + continue; + if (!backref->errors && rec->found_root_item) + continue; + fprintf(stderr, "\tunresolved ref root %llu dir %llu" + " index %llu namelen %u name %s error %x\n", + (unsigned long long)backref->ref_root, + (unsigned long long)backref->dir, + (unsigned long long)backref->index, + backref->namelen, backref->name, + backref->errors); + } + } + return errors > 0 ? 1 : 0; +} + +static int process_root_ref(struct extent_buffer *eb, int slot, + struct btrfs_key *key, + struct cache_tree *root_cache) +{ + u64 dirid; + u64 index; + u32 len; + u32 name_len; + struct btrfs_root_ref *ref; + char namebuf[BTRFS_NAME_LEN]; + int error; + + ref = btrfs_item_ptr(eb, slot, struct btrfs_root_ref); + + dirid = btrfs_root_ref_dirid(eb, ref); + index = btrfs_root_ref_sequence(eb, ref); + name_len = btrfs_root_ref_name_len(eb, ref); + + if (name_len <= BTRFS_NAME_LEN) { + len = name_len; + error = 0; + } else { + len = BTRFS_NAME_LEN; + error = REF_ERR_NAME_TOO_LONG; + } + read_extent_buffer(eb, namebuf, (unsigned long)(ref + 1), len); + + if (key->type == BTRFS_ROOT_REF_KEY) { + add_root_backref(root_cache, key->offset, key->objectid, dirid, + index, namebuf, len, key->type, error); + } else { + add_root_backref(root_cache, key->objectid, key->offset, dirid, + index, namebuf, len, key->type, error); + } + return 0; +} + static int check_fs_root(struct btrfs_root *root, + struct cache_tree *root_cache, struct walk_control *wc) { int ret = 0; @@ -1219,10 +1573,18 @@ static int check_fs_root(struct btrfs_root *root, int level; struct btrfs_path path; struct shared_node root_node; + struct root_record *rec; struct btrfs_root_item *root_item = &root->root_item; + if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) { + rec = get_root_rec(root_cache, root->root_key.objectid); + if (btrfs_root_refs(root_item) > 0) + rec->found_root_item = 1; + } + btrfs_init_path(&path); memset(&root_node, 0, sizeof(root_node)); + cache_tree_init(&root_node.root_cache); cache_tree_init(&root_node.inode_cache); level = btrfs_header_level(root->node); @@ -1266,6 +1628,8 @@ static int check_fs_root(struct btrfs_root *root, } btrfs_release_path(root, &path); + merge_root_recs(root, &root_node.root_cache, root_cache); + if (root_node.current) { root_node.current->checked = 1; maybe_free_inode_rec(&root_node.inode_cache, @@ -1280,13 +1644,15 @@ static int fs_root_objectid(u64 objectid) { if (objectid == BTRFS_FS_TREE_OBJECTID || objectid == BTRFS_TREE_RELOC_OBJECTID || + objectid == BTRFS_DATA_RELOC_TREE_OBJECTID || (objectid >= BTRFS_FIRST_FREE_OBJECTID && - objectid < BTRFS_LAST_FREE_OBJECTID)) + objectid <= BTRFS_LAST_FREE_OBJECTID)) return 1; return 0; } -static int check_fs_roots(struct btrfs_root *root) +static int check_fs_roots(struct btrfs_root *root, + struct cache_tree *root_cache) { struct btrfs_path path; struct btrfs_key key; @@ -1319,10 +1685,14 @@ static int check_fs_roots(struct btrfs_root *root) fs_root_objectid(key.objectid)) { tmp_root = btrfs_read_fs_root_no_cache(root->fs_info, &key); - ret = check_fs_root(tmp_root, &wc); + ret = check_fs_root(tmp_root, root_cache, &wc); if (ret) err = 1; btrfs_free_fs_root(root->fs_info, tmp_root); + } else if (key.type == BTRFS_ROOT_REF_KEY || + key.type == BTRFS_ROOT_BACKREF_KEY) { + process_root_ref(leaf, path.slots[0], &key, + root_cache); } path.slots[0]++; } @@ -1895,7 +2265,6 @@ static int add_data_backref(struct cache_tree *extent_cache, u64 bytenr, return 0; } - static int add_pending(struct cache_tree *pending, struct cache_tree *seen, u64 bytenr, u32 size) { @@ -2443,6 +2812,7 @@ static void print_usage(void) int main(int ac, char **av) { + struct cache_tree root_cache; struct btrfs_root *root; int ret; @@ -2450,6 +2820,7 @@ int main(int ac, char **av) print_usage(); radix_tree_init(); + cache_tree_init(&root_cache); root = open_ctree(av[1], 0, 0); if (root == NULL) @@ -2458,10 +2829,15 @@ int main(int ac, char **av) ret = check_extents(root); if (ret) goto out; - ret = check_fs_roots(root); + ret = check_fs_roots(root, &root_cache); + if (ret) + goto out; + ret = check_root_refs(root, &root_cache); out: + free_root_recs(&root_cache); close_ctree(root); + if (found_old_backref) { /* * there was a disk format change when mixed