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bcachefs: Reserve 8 bits in bch_reflink_p
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Better repair for reflink pointers, as well as propagating new inode
options to indirect extents, are going to require a few extra bits
bch_reflink_p: so claim a few from the high end of the destination
index.

Also add some missing bounds checking.

Signed-off-by: Kent Overstreet <[email protected]>
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Kent Overstreet committed Nov 4, 2024
1 parent c7fe151 commit e4b827e
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Showing 6 changed files with 43 additions and 27 deletions.
2 changes: 1 addition & 1 deletion fs/bcachefs/extent_update.c
Original file line number Diff line number Diff line change
Expand Up @@ -64,7 +64,7 @@ static int count_iters_for_insert(struct btree_trans *trans,
break;
case KEY_TYPE_reflink_p: {
struct bkey_s_c_reflink_p p = bkey_s_c_to_reflink_p(k);
u64 idx = le64_to_cpu(p.v->idx);
u64 idx = REFLINK_P_IDX(p.v);
unsigned sectors = bpos_min(*end, p.k->p).offset -
bkey_start_offset(p.k);
struct btree_iter iter;
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2 changes: 1 addition & 1 deletion fs/bcachefs/extents.c
Original file line number Diff line number Diff line change
Expand Up @@ -1492,7 +1492,7 @@ int bch2_cut_front_s(struct bpos where, struct bkey_s k)
case KEY_TYPE_reflink_p: {
struct bkey_s_reflink_p p = bkey_s_to_reflink_p(k);

le64_add_cpu(&p.v->idx, sub);
SET_REFLINK_P_IDX(p.v, REFLINK_P_IDX(p.v) + sub);
break;
}
case KEY_TYPE_inline_data:
Expand Down
14 changes: 5 additions & 9 deletions fs/bcachefs/io_read.c
Original file line number Diff line number Diff line change
Expand Up @@ -753,17 +753,13 @@ int __bch2_read_indirect_extent(struct btree_trans *trans,
unsigned *offset_into_extent,
struct bkey_buf *orig_k)
{
struct btree_iter iter;
struct bkey_s_c k;
u64 reflink_offset;
int ret;
struct bkey_i_reflink_p *p = bkey_i_to_reflink_p(orig_k->k);
u64 reflink_offset = REFLINK_P_IDX(&p->v) + *offset_into_extent;

reflink_offset = le64_to_cpu(bkey_i_to_reflink_p(orig_k->k)->v.idx) +
*offset_into_extent;

k = bch2_bkey_get_iter(trans, &iter, BTREE_ID_reflink,
struct btree_iter iter;
struct bkey_s_c k = bch2_bkey_get_iter(trans, &iter, BTREE_ID_reflink,
POS(0, reflink_offset), 0);
ret = bkey_err(k);
int ret = bkey_err(k);
if (ret)
goto err;

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45 changes: 31 additions & 14 deletions fs/bcachefs/reflink.c
Original file line number Diff line number Diff line change
Expand Up @@ -35,10 +35,10 @@ int bch2_reflink_p_validate(struct bch_fs *c, struct bkey_s_c k,
struct bkey_s_c_reflink_p p = bkey_s_c_to_reflink_p(k);
int ret = 0;

bkey_fsck_err_on(le64_to_cpu(p.v->idx) < le32_to_cpu(p.v->front_pad),
bkey_fsck_err_on(REFLINK_P_IDX(p.v) < le32_to_cpu(p.v->front_pad),
c, reflink_p_front_pad_bad,
"idx < front_pad (%llu < %u)",
le64_to_cpu(p.v->idx), le32_to_cpu(p.v->front_pad));
REFLINK_P_IDX(p.v), le32_to_cpu(p.v->front_pad));
fsck_err:
return ret;
}
Expand All @@ -49,7 +49,7 @@ void bch2_reflink_p_to_text(struct printbuf *out, struct bch_fs *c,
struct bkey_s_c_reflink_p p = bkey_s_c_to_reflink_p(k);

prt_printf(out, "idx %llu front_pad %u back_pad %u",
le64_to_cpu(p.v->idx),
REFLINK_P_IDX(p.v),
le32_to_cpu(p.v->front_pad),
le32_to_cpu(p.v->back_pad));
}
Expand All @@ -65,7 +65,7 @@ bool bch2_reflink_p_merge(struct bch_fs *c, struct bkey_s _l, struct bkey_s_c _r
*/
return false;

if (le64_to_cpu(l.v->idx) + l.k->size != le64_to_cpu(r.v->idx))
if (REFLINK_P_IDX(l.v) + l.k->size != REFLINK_P_IDX(r.v))
return false;

bch2_key_resize(l.k, l.k->size + r.k->size);
Expand Down Expand Up @@ -115,12 +115,12 @@ static int trans_trigger_reflink_p_segment(struct btree_trans *trans,
u64 pad;

pad = max_t(s64, le32_to_cpu(v->front_pad),
le64_to_cpu(v->idx) - bkey_start_offset(&k->k));
REFLINK_P_IDX(v) - bkey_start_offset(&k->k));
BUG_ON(pad > U32_MAX);
v->front_pad = cpu_to_le32(pad);

pad = max_t(s64, le32_to_cpu(v->back_pad),
k->k.p.offset - p.k->size - le64_to_cpu(v->idx));
k->k.p.offset - p.k->size - REFLINK_P_IDX(v));
BUG_ON(pad > U32_MAX);
v->back_pad = cpu_to_le32(pad);
}
Expand All @@ -147,8 +147,8 @@ static s64 gc_trigger_reflink_p_segment(struct btree_trans *trans,
struct bch_fs *c = trans->c;
struct reflink_gc *r;
int add = !(flags & BTREE_TRIGGER_overwrite) ? 1 : -1;
u64 start = le64_to_cpu(p.v->idx);
u64 end = le64_to_cpu(p.v->idx) + p.k->size;
u64 start = REFLINK_P_IDX(p.v);
u64 end = start + p.k->size;
u64 next_idx = end + le32_to_cpu(p.v->back_pad);
s64 ret = 0;
struct printbuf buf = PRINTBUF;
Expand Down Expand Up @@ -210,8 +210,8 @@ static int __trigger_reflink_p(struct btree_trans *trans,
struct bkey_s_c_reflink_p p = bkey_s_c_to_reflink_p(k);
int ret = 0;

u64 idx = le64_to_cpu(p.v->idx) - le32_to_cpu(p.v->front_pad);
u64 end = le64_to_cpu(p.v->idx) + p.k->size + le32_to_cpu(p.v->back_pad);
u64 idx = REFLINK_P_IDX(p.v) - le32_to_cpu(p.v->front_pad);
u64 end = REFLINK_P_IDX(p.v) + p.k->size + le32_to_cpu(p.v->back_pad);

if (flags & BTREE_TRIGGER_transactional) {
while (idx < end && !ret)
Expand Down Expand Up @@ -258,7 +258,16 @@ int bch2_trigger_reflink_p(struct btree_trans *trans,
int bch2_reflink_v_validate(struct bch_fs *c, struct bkey_s_c k,
enum bch_validate_flags flags)
{
return bch2_bkey_ptrs_validate(c, k, flags);
int ret = 0;

bkey_fsck_err_on(bkey_gt(k.k->p, POS(0, REFLINK_P_IDX_MAX)),
c, reflink_v_pos_bad,
"indirect extent above maximum position 0:%llu",
REFLINK_P_IDX_MAX);

ret = bch2_bkey_ptrs_validate(c, k, flags);
fsck_err:
return ret;
}

void bch2_reflink_v_to_text(struct printbuf *out, struct bch_fs *c,
Expand Down Expand Up @@ -358,6 +367,14 @@ static int bch2_make_extent_indirect(struct btree_trans *trans,
if (ret)
goto err;

/*
* XXX: we're assuming that 56 bits will be enough for the life of the
* filesystem: we need to implement wraparound, with a cursor in the
* logged ops btree:
*/
if (bkey_ge(reflink_iter.pos, POS(0, REFLINK_P_IDX_MAX - orig->k.size)))
return -ENOSPC;

r_v = bch2_trans_kmalloc(trans, sizeof(__le64) + bkey_bytes(&orig->k));
ret = PTR_ERR_OR_ZERO(r_v);
if (ret)
Expand Down Expand Up @@ -394,7 +411,7 @@ static int bch2_make_extent_indirect(struct btree_trans *trans,
memset(&r_p->v, 0, sizeof(r_p->v));
#endif

r_p->v.idx = cpu_to_le64(bkey_start_offset(&r_v->k));
SET_REFLINK_P_IDX(&r_p->v, bkey_start_offset(&r_v->k));

ret = bch2_trans_update(trans, extent_iter, &r_p->k_i,
BTREE_UPDATE_internal_snapshot_node);
Expand Down Expand Up @@ -533,11 +550,11 @@ s64 bch2_remap_range(struct bch_fs *c,
struct bkey_i_reflink_p *dst_p =
bkey_reflink_p_init(new_dst.k);

u64 offset = le64_to_cpu(src_p.v->idx) +
u64 offset = REFLINK_P_IDX(src_p.v) +
(src_want.offset -
bkey_start_offset(src_k.k));

dst_p->v.idx = cpu_to_le64(offset);
SET_REFLINK_P_IDX(&dst_p->v, offset);
} else {
BUG();
}
Expand Down
4 changes: 3 additions & 1 deletion fs/bcachefs/reflink_format.h
Original file line number Diff line number Diff line change
Expand Up @@ -4,7 +4,7 @@

struct bch_reflink_p {
struct bch_val v;
__le64 idx;
__le64 idx_flags;
/*
* A reflink pointer might point to an indirect extent which is then
* later split (by copygc or rebalance). If we only pointed to part of
Expand All @@ -17,6 +17,8 @@ struct bch_reflink_p {
__le32 back_pad;
} __packed __aligned(8);

LE64_BITMASK(REFLINK_P_IDX, struct bch_reflink_p, idx_flags, 0, 56);

struct bch_reflink_v {
struct bch_val v;
__le64 refcount;
Expand Down
3 changes: 2 additions & 1 deletion fs/bcachefs/sb-errors_format.h
Original file line number Diff line number Diff line change
Expand Up @@ -177,6 +177,7 @@ enum bch_fsck_flags {
x(ptr_stripe_redundant, 163, 0) \
x(reservation_key_nr_replicas_invalid, 164, 0) \
x(reflink_v_refcount_wrong, 165, 0) \
x(reflink_v_pos_bad, 292, 0) \
x(reflink_p_to_missing_reflink_v, 166, 0) \
x(stripe_pos_bad, 167, 0) \
x(stripe_val_size_bad, 168, 0) \
Expand Down Expand Up @@ -302,7 +303,7 @@ enum bch_fsck_flags {
x(accounting_key_replicas_devs_unsorted, 280, FSCK_AUTOFIX) \
x(accounting_key_version_0, 282, FSCK_AUTOFIX) \
x(logged_op_but_clean, 283, FSCK_AUTOFIX) \
x(MAX, 292, 0)
x(MAX, 293, 0)

enum bch_sb_error_id {
#define x(t, n, ...) BCH_FSCK_ERR_##t = n,
Expand Down

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