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bcachefs: Inode backpointers

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This patch adds two new inode fields, bi_dir and bi_dir_offset, that
point back to the inode's dirent.

Since we're only adding fields for a single backpointer, files that have
been hardlinked won't necessarily have valid backpointers: we also add a
new inode flag, BCH_INODE_BACKPTR_UNTRUSTED, that's set if an inode has
ever had multiple links to it. That's ok, because we only really need
this functionality for directories, which can never have multiple
hardlinks - when we add subvolumes, we'll need a way to enemurate and
print subvolumes, and this will let us reconstruct a path to a subvolume
root given a subvolume root inode.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This commit is contained in:
Kent Overstreet 2021-03-02 18:35:30 -05:00 committed by Kent Overstreet
parent e751c01a8e
commit ab2a29ccff
7 changed files with 125 additions and 40 deletions
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9
fs/bcachefs/bcachefs_format.h
View File

@ -710,7 +710,9 @@ struct bch_inode_generation {
x(bi_foreground_target, 16) \
x(bi_background_target, 16) \
x(bi_erasure_code, 16) \
x(bi_fields_set, 16)
x(bi_fields_set, 16) \
x(bi_dir, 64) \
x(bi_dir_offset, 64)
/* subset of BCH_INODE_FIELDS */
#define BCH_INODE_OPTS() \
@ -746,6 +748,7 @@ enum {
__BCH_INODE_I_SIZE_DIRTY= 5,
__BCH_INODE_I_SECTORS_DIRTY= 6,
__BCH_INODE_UNLINKED = 7,
__BCH_INODE_BACKPTR_UNTRUSTED = 8,
/* bits 20+ reserved for packed fields below: */
};
@ -758,6 +761,7 @@ enum {
#define BCH_INODE_I_SIZE_DIRTY (1 << __BCH_INODE_I_SIZE_DIRTY)
#define BCH_INODE_I_SECTORS_DIRTY (1 << __BCH_INODE_I_SECTORS_DIRTY)
#define BCH_INODE_UNLINKED (1 << __BCH_INODE_UNLINKED)
#define BCH_INODE_BACKPTR_UNTRUSTED (1 << __BCH_INODE_BACKPTR_UNTRUSTED)
LE32_BITMASK(INODE_STR_HASH, struct bch_inode, bi_flags, 20, 24);
LE32_BITMASK(INODE_NR_FIELDS, struct bch_inode, bi_flags, 24, 31);
@ -1208,7 +1212,8 @@ enum bcachefs_metadata_version {
bcachefs_metadata_version_bkey_renumber = 10,
bcachefs_metadata_version_inode_btree_change = 11,
bcachefs_metadata_version_snapshot = 12,
bcachefs_metadata_version_max = 13,
bcachefs_metadata_version_inode_backpointers = 13,
bcachefs_metadata_version_max = 14,
};
#define bcachefs_metadata_version_current (bcachefs_metadata_version_max - 1)

18
fs/bcachefs/dirent.c
View File

@ -141,7 +141,7 @@ static struct bkey_i_dirent *dirent_create_key(struct btree_trans *trans,
int bch2_dirent_create(struct btree_trans *trans,
u64 dir_inum, const struct bch_hash_info *hash_info,
u8 type, const struct qstr *name, u64 dst_inum,
int flags)
u64 *dir_offset, int flags)
{
struct bkey_i_dirent *dirent;
int ret;
@ -151,8 +151,11 @@ int bch2_dirent_create(struct btree_trans *trans,
if (ret)
return ret;
return bch2_hash_set(trans, bch2_dirent_hash_desc, hash_info,
dir_inum, &dirent->k_i, flags);
ret = bch2_hash_set(trans, bch2_dirent_hash_desc, hash_info,
dir_inum, &dirent->k_i, flags);
*dir_offset = dirent->k.p.offset;
return ret;
}
static void dirent_copy_target(struct bkey_i_dirent *dst,
@ -165,8 +168,8 @@ static void dirent_copy_target(struct bkey_i_dirent *dst,
int bch2_dirent_rename(struct btree_trans *trans,
u64 src_dir, struct bch_hash_info *src_hash,
u64 dst_dir, struct bch_hash_info *dst_hash,
const struct qstr *src_name, u64 *src_inum,
const struct qstr *dst_name, u64 *dst_inum,
const struct qstr *src_name, u64 *src_inum, u64 *src_offset,
const struct qstr *dst_name, u64 *dst_inum, u64 *dst_offset,
enum bch_rename_mode mode)
{
struct btree_iter *src_iter = NULL, *dst_iter = NULL;
@ -255,7 +258,7 @@ int bch2_dirent_rename(struct btree_trans *trans,
new_dst->k.p = src_iter->pos;
bch2_trans_update(trans, src_iter,
&new_dst->k_i, 0);
goto out;
goto out_set_offset;
} else {
/* If we're overwriting, we can't insert new_dst
* at a different slot because it has to
@ -278,6 +281,9 @@ int bch2_dirent_rename(struct btree_trans *trans,
bch2_trans_update(trans, src_iter, &new_src->k_i, 0);
bch2_trans_update(trans, dst_iter, &new_dst->k_i, 0);
out_set_offset:
*src_offset = new_src->k.p.offset;
*dst_offset = new_dst->k.p.offset;
out:
bch2_trans_iter_put(trans, src_iter);
bch2_trans_iter_put(trans, dst_iter);

6
fs/bcachefs/dirent.h
View File

@ -31,7 +31,7 @@ static inline unsigned dirent_val_u64s(unsigned len)
int bch2_dirent_create(struct btree_trans *, u64,
const struct bch_hash_info *, u8,
const struct qstr *, u64, int);
const struct qstr *, u64, u64 *, int);
int bch2_dirent_delete_at(struct btree_trans *,
const struct bch_hash_info *,
@ -46,8 +46,8 @@ enum bch_rename_mode {
int bch2_dirent_rename(struct btree_trans *,
u64, struct bch_hash_info *,
u64, struct bch_hash_info *,
const struct qstr *, u64 *,
const struct qstr *, u64 *,
const struct qstr *, u64 *, u64 *,
const struct qstr *, u64 *, u64 *,
enum bch_rename_mode);
struct btree_iter *

68
fs/bcachefs/fs-common.c
View File

@ -20,8 +20,10 @@ int bch2_create_trans(struct btree_trans *trans, u64 dir_inum,
{
struct bch_fs *c = trans->c;
struct btree_iter *dir_iter = NULL;
struct btree_iter *inode_iter = NULL;
struct bch_hash_info hash = bch2_hash_info_init(c, new_inode);
u64 now = bch2_current_time(trans->c);
u64 now = bch2_current_time(c);
u64 dir_offset = 0;
int ret;
dir_iter = bch2_inode_peek(trans, dir_u, dir_inum, BTREE_ITER_INTENT);
@ -34,7 +36,8 @@ int bch2_create_trans(struct btree_trans *trans, u64 dir_inum,
if (!name)
new_inode->bi_flags |= BCH_INODE_UNLINKED;
ret = bch2_inode_create(trans, new_inode);
inode_iter = bch2_inode_create(trans, new_inode);
ret = PTR_ERR_OR_ZERO(inode_iter);
if (ret)
goto err;
@ -66,11 +69,20 @@ int bch2_create_trans(struct btree_trans *trans, u64 dir_inum,
ret = bch2_dirent_create(trans, dir_inum, &dir_hash,
mode_to_type(new_inode->bi_mode),
name, new_inode->bi_inum,
&dir_offset,
BCH_HASH_SET_MUST_CREATE);
if (ret)
goto err;
}
if (c->sb.version >= bcachefs_metadata_version_inode_backpointers) {
new_inode->bi_dir = dir_u->bi_inum;
new_inode->bi_dir_offset = dir_offset;
}
ret = bch2_inode_write(trans, inode_iter, new_inode);
err:
bch2_trans_iter_put(trans, inode_iter);
bch2_trans_iter_put(trans, dir_iter);
return ret;
}
@ -79,9 +91,11 @@ int bch2_link_trans(struct btree_trans *trans, u64 dir_inum,
u64 inum, struct bch_inode_unpacked *dir_u,
struct bch_inode_unpacked *inode_u, const struct qstr *name)
{
struct bch_fs *c = trans->c;
struct btree_iter *dir_iter = NULL, *inode_iter = NULL;
struct bch_hash_info dir_hash;
u64 now = bch2_current_time(trans->c);
u64 now = bch2_current_time(c);
u64 dir_offset = 0;
int ret;
inode_iter = bch2_inode_peek(trans, inode_u, inum, BTREE_ITER_INTENT);
@ -92,6 +106,8 @@ int bch2_link_trans(struct btree_trans *trans, u64 dir_inum,
inode_u->bi_ctime = now;
bch2_inode_nlink_inc(inode_u);
inode_u->bi_flags |= BCH_INODE_BACKPTR_UNTRUSTED;
dir_iter = bch2_inode_peek(trans, dir_u, dir_inum, 0);
ret = PTR_ERR_OR_ZERO(dir_iter);
if (ret)
@ -99,12 +115,21 @@ int bch2_link_trans(struct btree_trans *trans, u64 dir_inum,
dir_u->bi_mtime = dir_u->bi_ctime = now;
dir_hash = bch2_hash_info_init(trans->c, dir_u);
dir_hash = bch2_hash_info_init(c, dir_u);
ret = bch2_dirent_create(trans, dir_inum, &dir_hash,
mode_to_type(inode_u->bi_mode),
name, inum, BCH_HASH_SET_MUST_CREATE) ?:
bch2_inode_write(trans, dir_iter, dir_u) ?:
ret = bch2_dirent_create(trans, dir_inum, &dir_hash,
mode_to_type(inode_u->bi_mode),
name, inum, &dir_offset,
BCH_HASH_SET_MUST_CREATE);
if (ret)
goto err;
if (c->sb.version >= bcachefs_metadata_version_inode_backpointers) {
inode_u->bi_dir = dir_inum;
inode_u->bi_dir_offset = dir_offset;
}
ret = bch2_inode_write(trans, dir_iter, dir_u) ?:
bch2_inode_write(trans, inode_iter, inode_u);
err:
bch2_trans_iter_put(trans, dir_iter);
@ -117,10 +142,11 @@ int bch2_unlink_trans(struct btree_trans *trans,
struct bch_inode_unpacked *inode_u,
const struct qstr *name)
{
struct bch_fs *c = trans->c;
struct btree_iter *dir_iter = NULL, *dirent_iter = NULL,
*inode_iter = NULL;
struct bch_hash_info dir_hash;
u64 inum, now = bch2_current_time(trans->c);
u64 inum, now = bch2_current_time(c);
struct bkey_s_c k;
int ret;
@ -129,7 +155,7 @@ int bch2_unlink_trans(struct btree_trans *trans,
if (ret)
goto err;
dir_hash = bch2_hash_info_init(trans->c, dir_u);
dir_hash = bch2_hash_info_init(c, dir_u);
dirent_iter = __bch2_dirent_lookup_trans(trans, dir_inum, &dir_hash,
name, BTREE_ITER_INTENT);
@ -195,10 +221,12 @@ int bch2_rename_trans(struct btree_trans *trans,
const struct qstr *dst_name,
enum bch_rename_mode mode)
{
struct bch_fs *c = trans->c;
struct btree_iter *src_dir_iter = NULL, *dst_dir_iter = NULL;
struct btree_iter *src_inode_iter = NULL, *dst_inode_iter = NULL;
struct bch_hash_info src_hash, dst_hash;
u64 src_inode, dst_inode, now = bch2_current_time(trans->c);
u64 src_inode, src_offset, dst_inode, dst_offset;
u64 now = bch2_current_time(c);
int ret;
src_dir_iter = bch2_inode_peek(trans, src_dir_u, src_dir,
@ -207,7 +235,7 @@ int bch2_rename_trans(struct btree_trans *trans,
if (ret)
goto err;
src_hash = bch2_hash_info_init(trans->c, src_dir_u);
src_hash = bch2_hash_info_init(c, src_dir_u);
if (dst_dir != src_dir) {
dst_dir_iter = bch2_inode_peek(trans, dst_dir_u, dst_dir,
@ -216,7 +244,7 @@ int bch2_rename_trans(struct btree_trans *trans,
if (ret)
goto err;
dst_hash = bch2_hash_info_init(trans->c, dst_dir_u);
dst_hash = bch2_hash_info_init(c, dst_dir_u);
} else {
dst_dir_u = src_dir_u;
dst_hash = src_hash;
@ -225,8 +253,8 @@ int bch2_rename_trans(struct btree_trans *trans,
ret = bch2_dirent_rename(trans,
src_dir, &src_hash,
dst_dir, &dst_hash,
src_name, &src_inode,
dst_name, &dst_inode,
src_name, &src_inode, &src_offset,
dst_name, &dst_inode, &dst_offset,
mode);
if (ret)
goto err;
@ -245,6 +273,16 @@ int bch2_rename_trans(struct btree_trans *trans,
goto err;
}
if (c->sb.version >= bcachefs_metadata_version_inode_backpointers) {
src_inode_u->bi_dir = dst_dir_u->bi_inum;
src_inode_u->bi_dir_offset = dst_offset;
if (mode == BCH_RENAME_EXCHANGE) {
dst_inode_u->bi_dir = src_dir_u->bi_inum;
dst_inode_u->bi_dir_offset = src_offset;
}
}
if (mode == BCH_RENAME_OVERWRITE) {
if (S_ISDIR(src_inode_u->bi_mode) !=
S_ISDIR(dst_inode_u->bi_mode)) {

43
fs/bcachefs/fsck.c
View File

@ -675,6 +675,39 @@ static int check_dirents(struct bch_fs *c)
continue;
}
if (!target.bi_nlink &&
!(target.bi_flags & BCH_INODE_BACKPTR_UNTRUSTED) &&
(target.bi_dir != k.k->p.inode ||
target.bi_dir_offset != k.k->p.offset) &&
(fsck_err_on(c->sb.version >= bcachefs_metadata_version_inode_backpointers, c,
"inode %llu has wrong backpointer:\n"
"got %llu:%llu\n"
"should be %llu:%llu",
d_inum,
target.bi_dir,
target.bi_dir_offset,
k.k->p.inode,
k.k->p.offset) ||
c->opts.version_upgrade)) {
struct bkey_inode_buf p;
target.bi_dir = k.k->p.inode;
target.bi_dir_offset = k.k->p.offset;
bch2_trans_unlock(&trans);
bch2_inode_pack(c, &p, &target);
ret = bch2_btree_insert(c, BTREE_ID_inodes,
&p.inode.k_i, NULL, NULL,
BTREE_INSERT_NOFAIL|
BTREE_INSERT_LAZY_RW);
if (ret) {
bch_err(c, "error in fsck: error %i updating inode", ret);
goto err;
}
continue;
}
if (fsck_err_on(have_target &&
d.v->d_type !=
mode_to_type(target.bi_mode), c,
@ -1314,6 +1347,16 @@ static int check_inode(struct btree_trans *trans,
do_update = true;
}
if (!S_ISDIR(u.bi_mode) &&
u.bi_nlink &&
!(u.bi_flags & BCH_INODE_BACKPTR_UNTRUSTED) &&
(fsck_err_on(c->sb.version >= bcachefs_metadata_version_inode_backpointers, c,
"inode missing BCH_INODE_BACKPTR_UNTRUSTED flags") ||
c->opts.version_upgrade)) {
u.bi_flags |= BCH_INODE_BACKPTR_UNTRUSTED;
do_update = true;
}
if (do_update) {
struct bkey_inode_buf p;

18
fs/bcachefs/inode.c
View File

@ -470,11 +470,10 @@ static inline u32 bkey_generation(struct bkey_s_c k)
}
}
int bch2_inode_create(struct btree_trans *trans,
struct bch_inode_unpacked *inode_u)
struct btree_iter *bch2_inode_create(struct btree_trans *trans,
struct bch_inode_unpacked *inode_u)
{
struct bch_fs *c = trans->c;
struct bkey_inode_buf *inode_p;
struct btree_iter *iter = NULL;
struct bkey_s_c k;
u64 min, max, start, *hint;
@ -494,10 +493,6 @@ int bch2_inode_create(struct btree_trans *trans,
if (start >= max || start < min)
start = min;
inode_p = bch2_trans_kmalloc(trans, sizeof(*inode_p));
if (IS_ERR(inode_p))
return PTR_ERR(inode_p);
again:
for_each_btree_key(trans, iter, BTREE_ID_inodes, POS(0, start),
BTREE_ITER_SLOTS|BTREE_ITER_INTENT, k, ret) {
@ -521,7 +516,7 @@ int bch2_inode_create(struct btree_trans *trans,
bch2_trans_iter_put(trans, iter);
if (ret)
return ret;
return ERR_PTR(ret);
if (start != min) {
/* Retry from start */
@ -529,15 +524,12 @@ int bch2_inode_create(struct btree_trans *trans,
goto again;
}
return -ENOSPC;
return ERR_PTR(-ENOSPC);
found_slot:
*hint = k.k->p.offset;
inode_u->bi_inum = k.k->p.offset;
inode_u->bi_generation = bkey_generation(k);
ret = bch2_inode_write(trans, iter, inode_u);
bch2_trans_iter_put(trans, iter);
return ret;
return iter;
}
int bch2_inode_rm(struct bch_fs *c, u64 inode_nr, bool cached)

3
fs/bcachefs/inode.h
View File

@ -69,7 +69,8 @@ void bch2_inode_init(struct bch_fs *, struct bch_inode_unpacked *,
uid_t, gid_t, umode_t, dev_t,
struct bch_inode_unpacked *);
int bch2_inode_create(struct btree_trans *, struct bch_inode_unpacked *);
struct btree_iter *bch2_inode_create(struct btree_trans *,
struct bch_inode_unpacked *);
int bch2_inode_rm(struct bch_fs *, u64, bool);