Verify extent back references in btrfsck
This commit is contained in:
Chris Mason
David Woodhouse
parent
29bf1724b1
commit
c4603e35d7
2 changed files with 229 additions and 17 deletions
244
btrfsck.c
244
btrfsck.c
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@ -26,6 +26,7 @@
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#include "disk-io.h"
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#include "print-tree.h"
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#include "transaction.h"
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#include "list.h"
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static u64 bytes_used = 0;
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static u64 total_csum_bytes = 0;
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@ -34,12 +35,22 @@ static u64 btree_space_waste = 0;
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static u64 data_bytes_allocated = 0;
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static u64 data_bytes_referenced = 0;
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struct extent_backref {
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struct list_head list;
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u64 root;
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u64 generation;
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u64 owner;
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u64 offset;
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int found_extent_tree;
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int found_ref;
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};
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struct extent_record {
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struct list_head backrefs;
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struct cache_extent cache;
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struct btrfs_disk_key parent_key;
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u64 start;
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u64 nr;
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u64 owner;
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u32 refs;
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u32 extent_item_refs;
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int checked;
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@ -120,12 +131,74 @@ static int check_leaf(struct btrfs_root *root,
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return 0;
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}
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static int all_backpointers_checked(struct extent_record *rec, int print_errs)
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{
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struct list_head *cur = rec->backrefs.next;
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struct extent_backref *back;
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u32 found = 0;
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int err = 0;
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while(cur != &rec->backrefs) {
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back = list_entry(cur, struct extent_backref, list);
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cur = cur->next;
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if (!back->found_extent_tree) {
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err = 1;
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if (!print_errs)
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goto out;
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fprintf(stderr, "Backref %llu [%llu %llu %llu %llu] "
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"not found in extent tree\n",
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(unsigned long long)rec->start,
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(unsigned long long)back->root,
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(unsigned long long)back->generation,
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(unsigned long long)back->owner,
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(unsigned long long)back->offset);
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}
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if (!back->found_ref) {
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err = 1;
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if (!print_errs)
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goto out;
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fprintf(stderr, "Backref %llu [%llu %llu %llu %llu] "
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"not referenced\n",
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(unsigned long long)rec->start,
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(unsigned long long)back->root,
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(unsigned long long)back->generation,
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(unsigned long long)back->owner,
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(unsigned long long)back->offset);
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}
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found++;
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}
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if (found != rec->refs) {
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err = 1;
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if (!print_errs)
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goto out;
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fprintf(stderr, "Incorrect backref count on %llu found %u "
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"wanted %u\n", (unsigned long long)rec->start,
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found, rec->refs);
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}
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out:
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return err;
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}
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static int free_all_backrefs(struct extent_record *rec)
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{
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struct extent_backref *back;
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struct list_head *cur;
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while (!list_empty(&rec->backrefs)) {
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cur = rec->backrefs.next;
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back = list_entry(cur, struct extent_backref, list);
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list_del(cur);
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free(back);
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}
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return 0;
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}
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static int maybe_free_extent_rec(struct cache_tree *extent_cache,
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struct extent_record *rec)
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{
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if (rec->checked && rec->extent_item_refs == rec->refs &&
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rec->refs > 0) {
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rec->refs > 0 && !all_backpointers_checked(rec, 0)) {
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remove_cache_extent(extent_cache, &rec->cache);
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free_all_backrefs(rec);
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free(rec);
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}
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return 0;
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@ -154,10 +227,45 @@ static int check_block(struct btrfs_root *root,
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return ret;
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}
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static struct extent_backref *find_backref(struct extent_record *rec,
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u64 root, u64 gen,
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u64 owner, u64 owner_offset)
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{
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struct list_head *cur = rec->backrefs.next;
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struct extent_backref *back;
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while(cur != &rec->backrefs) {
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back = list_entry(cur, struct extent_backref, list);
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cur = cur->next;
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if (back->root != root || gen != back->generation)
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continue;
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if (owner < BTRFS_FIRST_FREE_OBJECTID)
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return back;
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if (owner != back->owner || owner_offset != back->offset)
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continue;
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return back;
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}
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return NULL;
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}
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static struct extent_backref *alloc_backref(struct extent_record *rec,
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u64 root, u64 gen, u64 owner,
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u64 owner_offset)
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{
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struct extent_backref *ref = malloc(sizeof(*ref));
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ref->root = root;
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ref->generation = gen;
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ref->owner = owner;
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ref->offset = owner_offset;
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ref->found_extent_tree = 0;
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ref->found_ref = 0;
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list_add_tail(&ref->list, &rec->backrefs);
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return ref;
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}
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static int add_extent_rec(struct cache_tree *extent_cache,
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struct btrfs_disk_key *parent_key,
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u64 ref, u64 start,
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u64 nr, u64 owner,
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u64 ref, u64 start, u64 nr,
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u32 extent_item_refs, int inc_ref, int set_checked)
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{
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struct extent_record *rec;
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@ -169,6 +277,9 @@ static int add_extent_rec(struct cache_tree *extent_cache,
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rec = container_of(cache, struct extent_record, cache);
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if (inc_ref)
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rec->refs++;
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if (rec->nr == 1)
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rec->nr = nr;
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if (start != rec->start) {
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fprintf(stderr, "warning, start mismatch %llu %llu\n",
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(unsigned long long)rec->start,
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@ -177,12 +288,21 @@ static int add_extent_rec(struct cache_tree *extent_cache,
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}
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if (extent_item_refs) {
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if (rec->extent_item_refs) {
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fprintf(stderr, "block %llu rec extent_item_refs %u, passed %u\n", (unsigned long long)start, rec->extent_item_refs, extent_item_refs);
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fprintf(stderr, "block %llu rec "
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"extent_item_refs %u, passed %u\n",
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(unsigned long long)start,
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rec->extent_item_refs,
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extent_item_refs);
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}
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rec->extent_item_refs = extent_item_refs;
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}
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if (set_checked)
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rec->checked = 1;
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if (parent_key)
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memcpy(&rec->parent_key, parent_key,
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sizeof(*parent_key));
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maybe_free_extent_rec(extent_cache, rec);
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return ret;
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}
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@ -191,8 +311,8 @@ static int add_extent_rec(struct cache_tree *extent_cache,
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extent_item_refs = 0;
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rec->start = start;
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rec->nr = nr;
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rec->owner = owner;
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rec->checked = 0;
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INIT_LIST_HEAD(&rec->backrefs);
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if (inc_ref)
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rec->refs = 1;
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@ -219,6 +339,60 @@ static int add_extent_rec(struct cache_tree *extent_cache,
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return ret;
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}
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static int add_backref(struct cache_tree *extent_cache, u64 bytenr,
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u64 root, u64 gen, u64 owner, u64 owner_offset,
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int found_ref)
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{
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struct extent_record *rec;
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struct extent_backref *back;
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struct cache_extent *cache;
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if (root < BTRFS_FS_TREE_OBJECTID)
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gen = 0;
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cache = find_cache_extent(extent_cache, bytenr, 1);
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if (!cache) {
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add_extent_rec(extent_cache, NULL, 0, bytenr, 1, 0, 0, 0);
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cache = find_cache_extent(extent_cache, bytenr, 1);
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if (!cache)
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abort();
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}
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rec = container_of(cache, struct extent_record, cache);
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if (rec->start != bytenr) {
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abort();
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}
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back = find_backref(rec, root, gen, owner, owner_offset);
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if (!back)
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back = alloc_backref(rec, root, gen, owner, owner_offset);
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if (found_ref) {
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if (back->found_ref) {
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fprintf(stderr, "Back ref already exists for %llu "
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"root %llu gen %llu owner %llu offset %llu\n",
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(unsigned long long)bytenr,
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(unsigned long long)root,
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(unsigned long long)gen,
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(unsigned long long)owner,
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(unsigned long long)owner_offset);
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}
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back->found_ref = 1;
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} else {
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if (back->found_extent_tree) {
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fprintf(stderr, "Extent back ref already exists "
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"for %llu root %llu gen %llu owner %llu "
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"offset %llu\n", (unsigned long long)bytenr,
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(unsigned long long)root,
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(unsigned long long)gen,
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(unsigned long long)owner,
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(unsigned long long)owner_offset);
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}
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back->found_extent_tree = 1;
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}
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return 0;
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}
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static int add_pending(struct cache_tree *pending,
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struct cache_tree *seen, u64 bytenr, u32 size)
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{
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@ -314,6 +488,7 @@ static int run_next_block(struct btrfs_root *root,
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int ret;
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int i;
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int nritems;
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struct btrfs_extent_ref *ref;
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struct btrfs_leaf *leaf;
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struct btrfs_node *node;
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struct btrfs_disk_key *disk_key;
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@ -375,14 +550,12 @@ static int run_next_block(struct btrfs_root *root,
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BTRFS_EXTENT_ITEM_KEY) {
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struct btrfs_key found;
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struct btrfs_extent_item *ei;
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btrfs_disk_key_to_cpu(&found,
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&leaf->items[i].key);
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btrfs_disk_key_to_cpu(&found, disk_key);
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ei = btrfs_item_ptr(leaf, i,
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struct btrfs_extent_item);
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add_extent_rec(extent_cache, NULL, 0,
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found.objectid,
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found.offset,
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0,
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btrfs_extent_refs(ei), 0, 0);
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continue;
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}
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@ -406,7 +579,20 @@ static int run_next_block(struct btrfs_root *root,
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#endif
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continue;
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}
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if (btrfs_disk_key_type(&leaf->items[i].key) !=
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if (btrfs_disk_key_type(disk_key) ==
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BTRFS_EXTENT_REF_KEY) {
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ref = btrfs_item_ptr(leaf, i,
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struct btrfs_extent_ref);
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add_backref(extent_cache,
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btrfs_disk_key_objectid(disk_key),
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btrfs_ref_root(ref),
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btrfs_ref_generation(ref),
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btrfs_ref_objectid(ref),
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btrfs_ref_offset(ref), 0);
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continue;
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}
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if (btrfs_disk_key_type(disk_key) !=
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BTRFS_EXTENT_DATA_KEY)
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continue;
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fi = btrfs_item_ptr(leaf, i,
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@ -424,8 +610,13 @@ static int run_next_block(struct btrfs_root *root,
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ret = add_extent_rec(extent_cache, NULL, bytenr,
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btrfs_file_extent_disk_bytenr(fi),
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btrfs_file_extent_disk_num_bytes(fi),
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btrfs_disk_key_objectid(&leaf->items[i].key),
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0, 1, 1);
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add_backref(extent_cache,
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btrfs_file_extent_disk_bytenr(fi),
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btrfs_header_owner(&leaf->header),
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btrfs_header_generation(&leaf->header),
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btrfs_disk_key_objectid(disk_key),
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btrfs_disk_key_offset(disk_key), 1);
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BUG_ON(ret);
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}
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} else {
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@ -438,9 +629,15 @@ static int run_next_block(struct btrfs_root *root,
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ret = add_extent_rec(extent_cache,
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&node->ptrs[i].key,
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bytenr, ptr, size,
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btrfs_header_owner(&node->header),
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0, 1, 0);
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BUG_ON(ret);
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add_backref(extent_cache, ptr,
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btrfs_header_owner(&node->header),
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btrfs_header_generation(&node->header),
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level - 1,
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btrfs_disk_key_objectid(&node->ptrs[i].key), 1);
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if (level > 1) {
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add_pending(nodes, seen, ptr, size);
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} else {
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@ -462,14 +659,18 @@ static int add_root_to_pending(struct btrfs_buffer *buf,
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struct cache_tree *pending,
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struct cache_tree *seen,
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struct cache_tree *reada,
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struct cache_tree *nodes)
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struct cache_tree *nodes, u64 root_objectid)
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{
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if (btrfs_header_level(&buf->node.header) > 0)
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add_pending(nodes, seen, buf->bytenr, buf->size);
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else
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add_pending(pending, seen, buf->bytenr, buf->size);
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add_extent_rec(extent_cache, NULL, 0, buf->bytenr, buf->size,
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btrfs_header_owner(&buf->node.header), 0, 1, 0);
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0, 1, 0);
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add_backref(extent_cache, buf->bytenr, root_objectid,
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btrfs_header_generation(&buf->node.header),
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btrfs_header_level(&buf->node.header), 0, 1);
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return 0;
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}
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@ -494,7 +695,15 @@ int check_extent_refs(struct btrfs_root *root,
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rec->refs);
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err = 1;
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}
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if (all_backpointers_checked(rec, 1)) {
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fprintf(stderr, "backpointer mismatch on [%llu %llu]\n",
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(unsigned long long)rec->start,
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(unsigned long long)rec->nr);
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err = 1;
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}
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remove_cache_extent(extent_cache, cache);
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free_all_backrefs(rec);
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free(rec);
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}
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return err;
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@ -536,7 +745,8 @@ int main(int ac, char **av) {
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}
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add_root_to_pending(root->fs_info->tree_root->node, bits, bits_nr,
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&extent_cache, &pending, &seen, &reada, &nodes);
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&extent_cache, &pending, &seen, &reada, &nodes,
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root->fs_info->tree_root->root_key.objectid);
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btrfs_init_path(&path);
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key.offset = 0;
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@ -559,6 +769,7 @@ int main(int ac, char **av) {
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&leaf->items[path.slots[0]].key);
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if (btrfs_key_type(&found_key) == BTRFS_ROOT_ITEM_KEY) {
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struct btrfs_buffer *buf;
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ri = btrfs_item_ptr(leaf, path.slots[0],
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struct btrfs_root_item);
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buf = read_tree_block(root->fs_info->tree_root,
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@ -566,7 +777,8 @@ int main(int ac, char **av) {
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btrfs_level_size(root,
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btrfs_root_level(ri)));
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add_root_to_pending(buf, bits, bits_nr, &extent_cache,
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&pending, &seen, &reada, &nodes);
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&pending, &seen, &reada, &nodes,
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found_key.objectid);
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btrfs_block_release(root->fs_info->tree_root, buf);
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}
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path.slots[0]++;
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@ -279,7 +279,7 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans, struct
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return 0;
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memcpy(&snap_key, &root->root_key, sizeof(snap_key));
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root->root_key.offset++;
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root->root_key.offset = trans->transid;
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btrfs_set_root_bytenr(&root->root_item, root->node->bytenr);
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root->root_item.level =
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