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btrfsprogs/0003-btrfsck-check-root-back-forward-references.patch

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From 6f3cf25a4e7932bc737ed06bc95f73f80772092d Mon Sep 17 00:00:00 2001
From: Yan, Zheng <zheng.yan@oracle.com>
Date: Mon, 21 Sep 2009 16:03:57 -0400
Subject: [PATCH 3/4] 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 <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
---
btrfsck.c | 444 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++-----
1 files changed, 410 insertions(+), 34 deletions(-)
diff --git a/btrfsck.c b/btrfsck.c
index 40c90f8..73f1836 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
--
1.6.6.1
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