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authorKent Overstreet <kent.overstreet@linux.dev>2024-03-31 02:03:03 -0400
committerKent Overstreet <kent.overstreet@linux.dev>2024-04-03 14:46:51 -0400
commitcc0532900bcf1896a81dcdd30873ffa6c4f6926b (patch)
tree1c07c7c2c906d5f48dc470076beabcc2c81cdfef
parent4c02e63dadc7f5a92732ce3e267d0511749f60fb (diff)
bcachefs: Subvolume reconstruction
We can now recreate missing subvolumes from dirents and/or inodes. Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
-rw-r--r--fs/bcachefs/fsck.c167
1 files changed, 148 insertions, 19 deletions
diff --git a/fs/bcachefs/fsck.c b/fs/bcachefs/fsck.c
index b704fb0dda95..c1edc5647ba0 100644
--- a/fs/bcachefs/fsck.c
+++ b/fs/bcachefs/fsck.c
@@ -63,9 +63,7 @@ static int subvol_lookup(struct btree_trans *trans, u32 subvol,
u32 *snapshot, u64 *inum)
{
struct bch_subvolume s;
- int ret;
-
- ret = bch2_subvolume_get(trans, subvol, false, 0, &s);
+ int ret = bch2_subvolume_get(trans, subvol, false, 0, &s);
*snapshot = le32_to_cpu(s.snapshot);
*inum = le64_to_cpu(s.inode);
@@ -170,7 +168,8 @@ err:
/* Get lost+found, create if it doesn't exist: */
static int lookup_lostfound(struct btree_trans *trans, u32 snapshot,
- struct bch_inode_unpacked *lostfound)
+ struct bch_inode_unpacked *lostfound,
+ u64 reattaching_inum)
{
struct bch_fs *c = trans->c;
struct qstr lostfound_str = QSTR("lost+found");
@@ -185,19 +184,36 @@ static int lookup_lostfound(struct btree_trans *trans, u32 snapshot,
return ret;
subvol_inum root_inum = { .subvol = le32_to_cpu(st.master_subvol) };
- u32 subvol_snapshot;
- ret = subvol_lookup(trans, le32_to_cpu(st.master_subvol),
- &subvol_snapshot, &root_inum.inum);
- bch_err_msg(c, ret, "looking up root subvol");
+ struct bch_subvolume subvol;
+ ret = bch2_subvolume_get(trans, le32_to_cpu(st.master_subvol),
+ false, 0, &subvol);
+ bch_err_msg(c, ret, "looking up root subvol %u for snapshot %u",
+ le32_to_cpu(st.master_subvol), snapshot);
if (ret)
return ret;
+ if (!subvol.inode) {
+ struct btree_iter iter;
+ struct bkey_i_subvolume *subvol = bch2_bkey_get_mut_typed(trans, &iter,
+ BTREE_ID_subvolumes, POS(0, le32_to_cpu(st.master_subvol)),
+ 0, subvolume);
+ ret = PTR_ERR_OR_ZERO(subvol);
+ if (ret)
+ return ret;
+
+ subvol->v.inode = cpu_to_le64(reattaching_inum);
+ bch2_trans_iter_exit(trans, &iter);
+ }
+
+ root_inum.inum = le64_to_cpu(subvol.inode);
+
struct bch_inode_unpacked root_inode;
struct bch_hash_info root_hash_info;
u32 root_inode_snapshot = snapshot;
ret = lookup_inode(trans, root_inum.inum, &root_inode, &root_inode_snapshot);
- bch_err_msg(c, ret, "looking up root inode");
+ bch_err_msg(c, ret, "looking up root inode %llu for subvol %u",
+ root_inum.inum, le32_to_cpu(st.master_subvol));
if (ret)
return ret;
@@ -293,7 +309,7 @@ static int reattach_inode(struct btree_trans *trans,
snprintf(name_buf, sizeof(name_buf), "%llu", inode->bi_inum);
}
- ret = lookup_lostfound(trans, dirent_snapshot, &lostfound);
+ ret = lookup_lostfound(trans, dirent_snapshot, &lostfound, inode->bi_inum);
if (ret)
return ret;
@@ -364,6 +380,85 @@ static int reattach_subvol(struct btree_trans *trans, struct bkey_s_c_subvolume
return ret;
}
+static int reconstruct_subvol(struct btree_trans *trans, u32 snapshotid, u32 subvolid, u64 inum)
+{
+ struct bch_fs *c = trans->c;
+
+ if (!bch2_snapshot_is_leaf(c, snapshotid)) {
+ bch_err(c, "need to reconstruct subvol, but have interior node snapshot");
+ return -BCH_ERR_fsck_repair_unimplemented;
+ }
+
+ /*
+ * If inum isn't set, that means we're being called from check_dirents,
+ * not check_inodes - the root of this subvolume doesn't exist or we
+ * would have found it there:
+ */
+ if (!inum) {
+ struct btree_iter inode_iter = {};
+ struct bch_inode_unpacked new_inode;
+ u64 cpu = raw_smp_processor_id();
+
+ bch2_inode_init_early(c, &new_inode);
+ bch2_inode_init_late(&new_inode, bch2_current_time(c), 0, 0, S_IFDIR|0755, 0, NULL);
+
+ new_inode.bi_subvol = subvolid;
+
+ int ret = bch2_inode_create(trans, &inode_iter, &new_inode, snapshotid, cpu) ?:
+ bch2_btree_iter_traverse(&inode_iter) ?:
+ bch2_inode_write(trans, &inode_iter, &new_inode);
+ bch2_trans_iter_exit(trans, &inode_iter);
+ if (ret)
+ return ret;
+
+ inum = new_inode.bi_inum;
+ }
+
+ bch_info(c, "reconstructing subvol %u with root inode %llu", subvolid, inum);
+
+ struct bkey_i_subvolume *new_subvol = bch2_trans_kmalloc(trans, sizeof(*new_subvol));
+ int ret = PTR_ERR_OR_ZERO(new_subvol);
+ if (ret)
+ return ret;
+
+ bkey_subvolume_init(&new_subvol->k_i);
+ new_subvol->k.p.offset = subvolid;
+ new_subvol->v.snapshot = cpu_to_le32(snapshotid);
+ new_subvol->v.inode = cpu_to_le64(inum);
+ ret = bch2_btree_insert_trans(trans, BTREE_ID_subvolumes, &new_subvol->k_i, 0);
+ if (ret)
+ return ret;
+
+ struct btree_iter iter;
+ struct bkey_i_snapshot *s = bch2_bkey_get_mut_typed(trans, &iter,
+ BTREE_ID_snapshots, POS(0, snapshotid),
+ 0, snapshot);
+ ret = PTR_ERR_OR_ZERO(s);
+ bch_err_msg(c, ret, "getting snapshot %u", snapshotid);
+ if (ret)
+ return ret;
+
+ u32 snapshot_tree = le32_to_cpu(s->v.tree);
+
+ s->v.subvol = cpu_to_le32(subvolid);
+ SET_BCH_SNAPSHOT_SUBVOL(&s->v, true);
+ bch2_trans_iter_exit(trans, &iter);
+
+ struct bkey_i_snapshot_tree *st = bch2_bkey_get_mut_typed(trans, &iter,
+ BTREE_ID_snapshot_trees, POS(0, snapshot_tree),
+ 0, snapshot_tree);
+ ret = PTR_ERR_OR_ZERO(st);
+ bch_err_msg(c, ret, "getting snapshot tree %u", snapshot_tree);
+ if (ret)
+ return ret;
+
+ if (!st->v.master_subvol)
+ st->v.master_subvol = cpu_to_le32(subvolid);
+
+ bch2_trans_iter_exit(trans, &iter);
+ return 0;
+}
+
struct snapshots_seen_entry {
u32 id;
u32 equiv;
@@ -1065,6 +1160,11 @@ static int check_inode(struct btree_trans *trans,
if (ret && !bch2_err_matches(ret, ENOENT))
goto err;
+ if (ret && (c->sb.btrees_lost_data & BIT_ULL(BTREE_ID_subvolumes))) {
+ ret = reconstruct_subvol(trans, k.k->p.snapshot, u.bi_subvol, u.bi_inum);
+ goto do_update;
+ }
+
if (fsck_err_on(ret,
c, inode_bi_subvol_missing,
"inode %llu:%u bi_subvol points to missing subvolume %u",
@@ -1082,7 +1182,7 @@ static int check_inode(struct btree_trans *trans,
do_update = true;
}
}
-
+do_update:
if (do_update) {
ret = __bch2_fsck_write_inode(trans, &u, iter->pos.snapshot);
bch_err_msg(c, ret, "in fsck updating inode");
@@ -1785,6 +1885,7 @@ static int check_dirent_to_subvol(struct btree_trans *trans, struct btree_iter *
u32 parent_subvol = le32_to_cpu(d.v->d_parent_subvol);
u32 target_subvol = le32_to_cpu(d.v->d_child_subvol);
u32 parent_snapshot;
+ u32 new_parent_subvol = 0;
u64 parent_inum;
struct printbuf buf = PRINTBUF;
int ret = 0;
@@ -1793,6 +1894,27 @@ static int check_dirent_to_subvol(struct btree_trans *trans, struct btree_iter *
if (ret && !bch2_err_matches(ret, ENOENT))
return ret;
+ if (ret ||
+ (!ret && !bch2_snapshot_is_ancestor(c, parent_snapshot, d.k->p.snapshot))) {
+ int ret2 = find_snapshot_subvol(trans, d.k->p.snapshot, &new_parent_subvol);
+ if (ret2 && !bch2_err_matches(ret, ENOENT))
+ return ret2;
+ }
+
+ if (ret &&
+ !new_parent_subvol &&
+ (c->sb.btrees_lost_data & BIT_ULL(BTREE_ID_subvolumes))) {
+ /*
+ * Couldn't find a subvol for dirent's snapshot - but we lost
+ * subvols, so we need to reconstruct:
+ */
+ ret = reconstruct_subvol(trans, d.k->p.snapshot, parent_subvol, 0);
+ if (ret)
+ return ret;
+
+ parent_snapshot = d.k->p.snapshot;
+ }
+
if (fsck_err_on(ret, c, dirent_to_missing_parent_subvol,
"dirent parent_subvol points to missing subvolume\n%s",
(bch2_bkey_val_to_text(&buf, c, d.s_c), buf.buf)) ||
@@ -1801,10 +1923,10 @@ static int check_dirent_to_subvol(struct btree_trans *trans, struct btree_iter *
"dirent not visible in parent_subvol (not an ancestor of subvol snap %u)\n%s",
parent_snapshot,
(bch2_bkey_val_to_text(&buf, c, d.s_c), buf.buf))) {
- u32 new_parent_subvol;
- ret = find_snapshot_subvol(trans, d.k->p.snapshot, &new_parent_subvol);
- if (ret)
- goto err;
+ if (!new_parent_subvol) {
+ bch_err(c, "could not find a subvol for snapshot %u", d.k->p.snapshot);
+ return -BCH_ERR_fsck_repair_unimplemented;
+ }
struct bkey_i_dirent *new_dirent = bch2_bkey_make_mut_typed(trans, iter, &d.s_c, 0, dirent);
ret = PTR_ERR_OR_ZERO(new_dirent);
@@ -1850,9 +1972,16 @@ static int check_dirent_to_subvol(struct btree_trans *trans, struct btree_iter *
ret = lookup_inode(trans, target_inum, &subvol_root, &target_snapshot);
if (ret && !bch2_err_matches(ret, ENOENT))
- return ret;
+ goto err;
- if (fsck_err_on(parent_subvol != subvol_root.bi_parent_subvol,
+ if (ret) {
+ bch_err(c, "subvol %u points to missing inode root %llu", target_subvol, target_inum);
+ ret = -BCH_ERR_fsck_repair_unimplemented;
+ ret = 0;
+ goto err;
+ }
+
+ if (fsck_err_on(!ret && parent_subvol != subvol_root.bi_parent_subvol,
c, inode_bi_parent_wrong,
"subvol root %llu has wrong bi_parent_subvol: got %u, should be %u",
target_inum,
@@ -1860,13 +1989,13 @@ static int check_dirent_to_subvol(struct btree_trans *trans, struct btree_iter *
subvol_root.bi_parent_subvol = parent_subvol;
ret = __bch2_fsck_write_inode(trans, &subvol_root, target_snapshot);
if (ret)
- return ret;
+ goto err;
}
ret = check_dirent_target(trans, iter, d, &subvol_root,
target_snapshot);
if (ret)
- return ret;
+ goto err;
out:
err:
fsck_err: