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// SPDX-License-Identifier: GPL-2.0
#include "bcachefs.h"
#include "btree_key_cache.h"
#include "btree_update.h"
#include "errcode.h"
#include "error.h"
#include "fs.h"
#include "snapshot.h"
#include "subvolume.h"
#include <linux/random.h>
static int bch2_subvolume_delete(struct btree_trans *, u32);
static int check_subvol(struct btree_trans *trans,
struct btree_iter *iter,
struct bkey_s_c k)
{
struct bch_fs *c = trans->c;
struct bkey_s_c_subvolume subvol;
struct bch_snapshot snapshot;
unsigned snapid;
int ret = 0;
if (k.k->type != KEY_TYPE_subvolume)
return 0;
subvol = bkey_s_c_to_subvolume(k);
snapid = le32_to_cpu(subvol.v->snapshot);
ret = bch2_snapshot_lookup(trans, snapid, &snapshot);
if (bch2_err_matches(ret, ENOENT))
bch_err(c, "subvolume %llu points to nonexistent snapshot %u",
k.k->p.offset, snapid);
if (ret)
return ret;
if (BCH_SUBVOLUME_UNLINKED(subvol.v)) {
bch2_fs_lazy_rw(c);
ret = bch2_subvolume_delete(trans, iter->pos.offset);
if (ret)
bch_err_msg(c, ret, "deleting subvolume %llu", iter->pos.offset);
return ret ?: -BCH_ERR_transaction_restart_nested;
}
if (!BCH_SUBVOLUME_SNAP(subvol.v)) {
u32 snapshot_root = bch2_snapshot_root(c, le32_to_cpu(subvol.v->snapshot));
u32 snapshot_tree;
struct bch_snapshot_tree st;
rcu_read_lock();
snapshot_tree = snapshot_t(c, snapshot_root)->tree;
rcu_read_unlock();
ret = bch2_snapshot_tree_lookup(trans, snapshot_tree, &st);
bch2_fs_inconsistent_on(bch2_err_matches(ret, ENOENT), c,
"%s: snapshot tree %u not found", __func__, snapshot_tree);
if (ret)
return ret;
if (fsck_err_on(le32_to_cpu(st.master_subvol) != subvol.k->p.offset, c,
"subvolume %llu is not set as snapshot but is not master subvolume",
k.k->p.offset)) {
struct bkey_i_subvolume *s =
bch2_bkey_make_mut_typed(trans, iter, &subvol.s_c, 0, subvolume);
ret = PTR_ERR_OR_ZERO(s);
if (ret)
return ret;
SET_BCH_SUBVOLUME_SNAP(&s->v, true);
}
}
fsck_err:
return ret;
}
int bch2_check_subvols(struct bch_fs *c)
{
struct btree_iter iter;
struct bkey_s_c k;
int ret;
ret = bch2_trans_run(c,
for_each_btree_key_commit(&trans, iter,
BTREE_ID_subvolumes, POS_MIN, BTREE_ITER_PREFETCH, k,
NULL, NULL, BTREE_INSERT_LAZY_RW|BTREE_INSERT_NOFAIL,
check_subvol(&trans, &iter, k)));
if (ret)
bch_err_fn(c, ret);
return ret;
}
/* Subvolumes: */
int bch2_subvolume_invalid(const struct bch_fs *c, struct bkey_s_c k,
unsigned flags, struct printbuf *err)
{
if (bkey_lt(k.k->p, SUBVOL_POS_MIN) ||
bkey_gt(k.k->p, SUBVOL_POS_MAX)) {
prt_printf(err, "invalid pos");
return -BCH_ERR_invalid_bkey;
}
return 0;
}
void bch2_subvolume_to_text(struct printbuf *out, struct bch_fs *c,
struct bkey_s_c k)
{
struct bkey_s_c_subvolume s = bkey_s_c_to_subvolume(k);
prt_printf(out, "root %llu snapshot id %u",
le64_to_cpu(s.v->inode),
le32_to_cpu(s.v->snapshot));
if (bkey_val_bytes(s.k) > offsetof(struct bch_subvolume, parent))
prt_printf(out, " parent %u", le32_to_cpu(s.v->parent));
}
static __always_inline int
bch2_subvolume_get_inlined(struct btree_trans *trans, unsigned subvol,
bool inconsistent_if_not_found,
int iter_flags,
struct bch_subvolume *s)
{
int ret = bch2_bkey_get_val_typed(trans, BTREE_ID_subvolumes, POS(0, subvol),
iter_flags, subvolume, s);
bch2_fs_inconsistent_on(bch2_err_matches(ret, ENOENT) &&
inconsistent_if_not_found,
trans->c, "missing subvolume %u", subvol);
return ret;
}
int bch2_subvolume_get(struct btree_trans *trans, unsigned subvol,
bool inconsistent_if_not_found,
int iter_flags,
struct bch_subvolume *s)
{
return bch2_subvolume_get_inlined(trans, subvol, inconsistent_if_not_found, iter_flags, s);
}
int bch2_snapshot_get_subvol(struct btree_trans *trans, u32 snapshot,
struct bch_subvolume *subvol)
{
struct bch_snapshot snap;
return bch2_snapshot_lookup(trans, snapshot, &snap) ?:
bch2_subvolume_get(trans, le32_to_cpu(snap.subvol), true, 0, subvol);
}
int bch2_subvolume_get_snapshot(struct btree_trans *trans, u32 subvolid,
u32 *snapid)
{
struct btree_iter iter;
struct bkey_s_c_subvolume subvol;
int ret;
subvol = bch2_bkey_get_iter_typed(trans, &iter,
BTREE_ID_subvolumes, POS(0, subvolid),
BTREE_ITER_CACHED|BTREE_ITER_WITH_UPDATES,
subvolume);
ret = bkey_err(subvol);
bch2_fs_inconsistent_on(bch2_err_matches(ret, ENOENT), trans->c,
"missing subvolume %u", subvolid);
if (likely(!ret))
*snapid = le32_to_cpu(subvol.v->snapshot);
bch2_trans_iter_exit(trans, &iter);
return ret;
}
static int bch2_subvolume_reparent(struct btree_trans *trans,
struct btree_iter *iter,
struct bkey_s_c k,
u32 old_parent, u32 new_parent)
{
struct bkey_i_subvolume *s;
int ret;
if (k.k->type != KEY_TYPE_subvolume)
return 0;
if (bkey_val_bytes(k.k) > offsetof(struct bch_subvolume, parent) &&
le32_to_cpu(bkey_s_c_to_subvolume(k).v->parent) != old_parent)
return 0;
s = bch2_bkey_make_mut_typed(trans, iter, &k, 0, subvolume);
ret = PTR_ERR_OR_ZERO(s);
if (ret)
return ret;
s->v.parent = cpu_to_le32(new_parent);
return 0;
}
/*
* Separate from the snapshot tree in the snapshots btree, we record the tree
* structure of how snapshot subvolumes were created - the parent subvolume of
* each snapshot subvolume.
*
* When a subvolume is deleted, we scan for child subvolumes and reparant them,
* to avoid dangling references:
*/
static int bch2_subvolumes_reparent(struct btree_trans *trans, u32 subvolid_to_delete)
{
struct btree_iter iter;
struct bkey_s_c k;
struct bch_subvolume s;
return lockrestart_do(trans,
bch2_subvolume_get(trans, subvolid_to_delete, true,
BTREE_ITER_CACHED, &s)) ?:
for_each_btree_key_commit(trans, iter,
BTREE_ID_subvolumes, POS_MIN, BTREE_ITER_PREFETCH, k,
NULL, NULL, BTREE_INSERT_NOFAIL,
bch2_subvolume_reparent(trans, &iter, k,
subvolid_to_delete, le32_to_cpu(s.parent)));
}
/*
* Delete subvolume, mark snapshot ID as deleted, queue up snapshot
* deletion/cleanup:
*/
static int __bch2_subvolume_delete(struct btree_trans *trans, u32 subvolid)
{
struct btree_iter iter;
struct bkey_s_c_subvolume subvol;
struct btree_trans_commit_hook *h;
u32 snapid;
int ret = 0;
subvol = bch2_bkey_get_iter_typed(trans, &iter,
BTREE_ID_subvolumes, POS(0, subvolid),
BTREE_ITER_CACHED|BTREE_ITER_INTENT,
subvolume);
ret = bkey_err(subvol);
bch2_fs_inconsistent_on(bch2_err_matches(ret, ENOENT), trans->c,
"missing subvolume %u", subvolid);
if (ret)
return ret;
snapid = le32_to_cpu(subvol.v->snapshot);
ret = bch2_btree_delete_at(trans, &iter, 0);
if (ret)
goto err;
ret = bch2_snapshot_node_set_deleted(trans, snapid);
if (ret)
goto err;
h = bch2_trans_kmalloc(trans, sizeof(*h));
ret = PTR_ERR_OR_ZERO(h);
if (ret)
goto err;
h->fn = bch2_delete_dead_snapshots_hook;
bch2_trans_commit_hook(trans, h);
err:
bch2_trans_iter_exit(trans, &iter);
return ret;
}
static int bch2_subvolume_delete(struct btree_trans *trans, u32 subvolid)
{
return bch2_subvolumes_reparent(trans, subvolid) ?:
commit_do(trans, NULL, NULL, BTREE_INSERT_NOFAIL,
__bch2_subvolume_delete(trans, subvolid));
}
static void bch2_subvolume_wait_for_pagecache_and_delete(struct work_struct *work)
{
struct bch_fs *c = container_of(work, struct bch_fs,
snapshot_wait_for_pagecache_and_delete_work);
snapshot_id_list s;
u32 *id;
int ret = 0;
while (!ret) {
mutex_lock(&c->snapshots_unlinked_lock);
s = c->snapshots_unlinked;
darray_init(&c->snapshots_unlinked);
mutex_unlock(&c->snapshots_unlinked_lock);
if (!s.nr)
break;
bch2_evict_subvolume_inodes(c, &s);
for (id = s.data; id < s.data + s.nr; id++) {
ret = bch2_trans_run(c, bch2_subvolume_delete(&trans, *id));
if (ret) {
bch_err_msg(c, ret, "deleting subvolume %u", *id);
break;
}
}
darray_exit(&s);
}
bch2_write_ref_put(c, BCH_WRITE_REF_snapshot_delete_pagecache);
}
struct subvolume_unlink_hook {
struct btree_trans_commit_hook h;
u32 subvol;
};
static int bch2_subvolume_wait_for_pagecache_and_delete_hook(struct btree_trans *trans,
struct btree_trans_commit_hook *_h)
{
struct subvolume_unlink_hook *h = container_of(_h, struct subvolume_unlink_hook, h);
struct bch_fs *c = trans->c;
int ret = 0;
mutex_lock(&c->snapshots_unlinked_lock);
if (!snapshot_list_has_id(&c->snapshots_unlinked, h->subvol))
ret = snapshot_list_add(c, &c->snapshots_unlinked, h->subvol);
mutex_unlock(&c->snapshots_unlinked_lock);
if (ret)
return ret;
if (!bch2_write_ref_tryget(c, BCH_WRITE_REF_snapshot_delete_pagecache))
return -EROFS;
if (!queue_work(c->write_ref_wq, &c->snapshot_wait_for_pagecache_and_delete_work))
bch2_write_ref_put(c, BCH_WRITE_REF_snapshot_delete_pagecache);
return 0;
}
int bch2_subvolume_unlink(struct btree_trans *trans, u32 subvolid)
{
struct btree_iter iter;
struct bkey_i_subvolume *n;
struct subvolume_unlink_hook *h;
int ret = 0;
h = bch2_trans_kmalloc(trans, sizeof(*h));
ret = PTR_ERR_OR_ZERO(h);
if (ret)
return ret;
h->h.fn = bch2_subvolume_wait_for_pagecache_and_delete_hook;
h->subvol = subvolid;
bch2_trans_commit_hook(trans, &h->h);
n = bch2_bkey_get_mut_typed(trans, &iter,
BTREE_ID_subvolumes, POS(0, subvolid),
BTREE_ITER_CACHED, subvolume);
ret = PTR_ERR_OR_ZERO(n);
if (unlikely(ret)) {
bch2_fs_inconsistent_on(bch2_err_matches(ret, ENOENT), trans->c,
"missing subvolume %u", subvolid);
return ret;
}
SET_BCH_SUBVOLUME_UNLINKED(&n->v, true);
bch2_trans_iter_exit(trans, &iter);
return ret;
}
int bch2_subvolume_create(struct btree_trans *trans, u64 inode,
u32 src_subvolid,
u32 *new_subvolid,
u32 *new_snapshotid,
bool ro)
{
struct bch_fs *c = trans->c;
struct btree_iter dst_iter, src_iter = (struct btree_iter) { NULL };
struct bkey_i_subvolume *new_subvol = NULL;
struct bkey_i_subvolume *src_subvol = NULL;
u32 parent = 0, new_nodes[2], snapshot_subvols[2];
int ret = 0;
ret = bch2_bkey_get_empty_slot(trans, &dst_iter,
BTREE_ID_subvolumes, POS(0, U32_MAX));
if (ret == -BCH_ERR_ENOSPC_btree_slot)
ret = -BCH_ERR_ENOSPC_subvolume_create;
if (ret)
return ret;
snapshot_subvols[0] = dst_iter.pos.offset;
snapshot_subvols[1] = src_subvolid;
if (src_subvolid) {
/* Creating a snapshot: */
src_subvol = bch2_bkey_get_mut_typed(trans, &src_iter,
BTREE_ID_subvolumes, POS(0, src_subvolid),
BTREE_ITER_CACHED, subvolume);
ret = PTR_ERR_OR_ZERO(src_subvol);
if (unlikely(ret)) {
bch2_fs_inconsistent_on(bch2_err_matches(ret, ENOENT), c,
"subvolume %u not found", src_subvolid);
goto err;
}
parent = le32_to_cpu(src_subvol->v.snapshot);
}
ret = bch2_snapshot_node_create(trans, parent, new_nodes,
snapshot_subvols,
src_subvolid ? 2 : 1);
if (ret)
goto err;
if (src_subvolid) {
src_subvol->v.snapshot = cpu_to_le32(new_nodes[1]);
ret = bch2_trans_update(trans, &src_iter, &src_subvol->k_i, 0);
if (ret)
goto err;
}
new_subvol = bch2_bkey_alloc(trans, &dst_iter, 0, subvolume);
ret = PTR_ERR_OR_ZERO(new_subvol);
if (ret)
goto err;
new_subvol->v.flags = 0;
new_subvol->v.snapshot = cpu_to_le32(new_nodes[0]);
new_subvol->v.inode = cpu_to_le64(inode);
new_subvol->v.parent = cpu_to_le32(src_subvolid);
new_subvol->v.otime.lo = cpu_to_le64(bch2_current_time(c));
new_subvol->v.otime.hi = 0;
SET_BCH_SUBVOLUME_RO(&new_subvol->v, ro);
SET_BCH_SUBVOLUME_SNAP(&new_subvol->v, src_subvolid != 0);
*new_subvolid = new_subvol->k.p.offset;
*new_snapshotid = new_nodes[0];
err:
bch2_trans_iter_exit(trans, &src_iter);
bch2_trans_iter_exit(trans, &dst_iter);
return ret;
}
int bch2_fs_subvolumes_init(struct bch_fs *c)
{
INIT_WORK(&c->snapshot_delete_work, bch2_delete_dead_snapshots_work);
INIT_WORK(&c->snapshot_wait_for_pagecache_and_delete_work,
bch2_subvolume_wait_for_pagecache_and_delete);
mutex_init(&c->snapshots_unlinked_lock);
return 0;
}
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