From 18443cb9f005b5563e2e3da9b8ccd374a552c3b1 Mon Sep 17 00:00:00 2001 From: Kent Overstreet Date: Thu, 5 Aug 2021 00:41:41 -0400 Subject: [PATCH] bcachefs: Update data move path for snapshots The data move path operates on existing extents, and not within a subvolume as the regular IO paths do. It needs to change because it may cause existing extents to be split, and when splitting an existing extent in an ancestor snapshot we need to make sure the new split has the same visibility in child snapshots as the existing extent. Signed-off-by: Kent Overstreet --- fs/bcachefs/btree_update_leaf.c | 81 ++++++++++++++++++++++++++++----- fs/bcachefs/fsck.c | 35 +------------- fs/bcachefs/io.c | 3 +- fs/bcachefs/migrate.c | 6 ++- fs/bcachefs/move.c | 81 ++++++++++++++++++++++++++++++++- fs/bcachefs/subvolume.h | 38 ++++++++++++++++ 6 files changed, 195 insertions(+), 49 deletions(-) diff --git a/fs/bcachefs/btree_update_leaf.c b/fs/bcachefs/btree_update_leaf.c index 2fc134e345725..b4a2f2e322489 100644 --- a/fs/bcachefs/btree_update_leaf.c +++ b/fs/bcachefs/btree_update_leaf.c @@ -941,6 +941,43 @@ err: goto retry; } +static int check_pos_snapshot_overwritten(struct btree_trans *trans, + enum btree_id id, + struct bpos pos) +{ + struct bch_fs *c = trans->c; + struct btree_iter iter; + struct bkey_s_c k; + int ret; + + if (!snapshot_t(c, pos.snapshot)->children[0]) + return 0; + + bch2_trans_iter_init(trans, &iter, id, pos, + BTREE_ITER_NOT_EXTENTS| + BTREE_ITER_ALL_SNAPSHOTS); + while (1) { + k = bch2_btree_iter_prev(&iter); + ret = bkey_err(k); + if (ret) + break; + + if (!k.k) + break; + + if (bkey_cmp(pos, k.k->p)) + break; + + if (bch2_snapshot_is_ancestor(c, k.k->p.snapshot, pos.snapshot)) { + ret = 1; + break; + } + } + bch2_trans_iter_exit(trans, &iter); + + return ret; +} + static noinline int extent_front_merge(struct btree_trans *trans, struct btree_iter *iter, struct bkey_s_c k, @@ -958,14 +995,40 @@ static noinline int extent_front_merge(struct btree_trans *trans, bkey_reassemble(update, k); - if (bch2_bkey_merge(c, bkey_i_to_s(update), bkey_i_to_s_c(*insert))) { - ret = bch2_btree_delete_at(trans, iter, flags); - if (ret) - return ret; + if (!bch2_bkey_merge(c, bkey_i_to_s(update), bkey_i_to_s_c(*insert))) + return 0; - *insert = update; - } + ret = check_pos_snapshot_overwritten(trans, iter->btree_id, k.k->p) ?: + check_pos_snapshot_overwritten(trans, iter->btree_id, (*insert)->k.p); + if (ret < 0) + return ret; + if (ret) + return 0; + + ret = bch2_btree_delete_at(trans, iter, flags); + if (ret) + return ret; + + *insert = update; + return 0; +} + +static noinline int extent_back_merge(struct btree_trans *trans, + struct btree_iter *iter, + struct bkey_i *insert, + struct bkey_s_c k) +{ + struct bch_fs *c = trans->c; + int ret; + + ret = check_pos_snapshot_overwritten(trans, iter->btree_id, insert->k.p) ?: + check_pos_snapshot_overwritten(trans, iter->btree_id, k.k->p); + if (ret < 0) + return ret; + if (ret) + return 0; + bch2_bkey_merge(c, bkey_i_to_s(insert), k); return 0; } @@ -974,7 +1037,6 @@ static int bch2_trans_update_extent(struct btree_trans *trans, struct bkey_i *insert, enum btree_update_flags flags) { - struct bch_fs *c = trans->c; struct btree_iter iter, update_iter; struct bpos start = bkey_start_pos(&insert->k); struct bkey_i *update; @@ -1002,9 +1064,6 @@ static int bch2_trans_update_extent(struct btree_trans *trans, goto next; } - if (!bkey_cmp(k.k->p, start)) - goto next; - while (bkey_cmp(insert->k.p, bkey_start_pos(k.k)) > 0) { bool front_split = bkey_cmp(bkey_start_pos(k.k), start) < 0; bool back_split = bkey_cmp(k.k->p, insert->k.p) > 0; @@ -1120,7 +1179,7 @@ next: } if (bch2_bkey_maybe_mergable(&insert->k, k.k)) - bch2_bkey_merge(c, bkey_i_to_s(insert), k); + extent_back_merge(trans, &iter, insert, k); out: if (!bkey_deleted(&insert->k)) { /* diff --git a/fs/bcachefs/fsck.c b/fs/bcachefs/fsck.c index b4a6b3d2ed077..f9a6a0b3ce7a5 100644 --- a/fs/bcachefs/fsck.c +++ b/fs/bcachefs/fsck.c @@ -473,24 +473,6 @@ out: return ret; } -struct snapshots_seen { - struct bpos pos; - size_t nr; - size_t size; - u32 *d; -}; - -static void snapshots_seen_exit(struct snapshots_seen *s) -{ - kfree(s->d); - s->d = NULL; -} - -static void snapshots_seen_init(struct snapshots_seen *s) -{ - memset(s, 0, sizeof(*s)); -} - static int snapshots_seen_update(struct bch_fs *c, struct snapshots_seen *s, struct bpos pos) { pos.snapshot = snapshot_t(c, pos.snapshot)->equiv; @@ -499,26 +481,11 @@ static int snapshots_seen_update(struct bch_fs *c, struct snapshots_seen *s, str s->nr = 0; s->pos = pos; - if (s->nr == s->size) { - size_t new_size = max(s->size, 128UL) * 2; - u32 *d = krealloc(s->d, new_size * sizeof(s->d[0]), GFP_KERNEL); - - if (!d) { - bch_err(c, "error reallocating snapshots_seen table (new size %zu)", - new_size); - return -ENOMEM; - } - - s->size = new_size; - s->d = d; - } - /* Might get called multiple times due to lock restarts */ if (s->nr && s->d[s->nr - 1] == pos.snapshot) return 0; - s->d[s->nr++] = pos.snapshot; - return 0; + return snapshots_seen_add(c, s, pos.snapshot); } /** diff --git a/fs/bcachefs/io.c b/fs/bcachefs/io.c index bd96c6bebe184..002fd35e6bfea 100644 --- a/fs/bcachefs/io.c +++ b/fs/bcachefs/io.c @@ -1828,7 +1828,8 @@ static int __bch2_rbio_narrow_crcs(struct btree_trans *trans, if (!bch2_bkey_narrow_crcs(new, new_crc)) goto out; - ret = bch2_trans_update(trans, &iter, new, 0); + ret = bch2_trans_update(trans, &iter, new, + BTREE_UPDATE_INTERNAL_SNAPSHOT_NODE); out: bch2_trans_iter_exit(trans, &iter); return ret; diff --git a/fs/bcachefs/migrate.c b/fs/bcachefs/migrate.c index 1899326d9754e..7c764ee4ea09c 100644 --- a/fs/bcachefs/migrate.c +++ b/fs/bcachefs/migrate.c @@ -48,7 +48,8 @@ static int __bch2_dev_usrdata_drop(struct bch_fs *c, unsigned dev_idx, int flags bch2_trans_init(&trans, c, BTREE_ITER_MAX, 0); bch2_trans_iter_init(&trans, &iter, btree_id, POS_MIN, - BTREE_ITER_PREFETCH); + BTREE_ITER_PREFETCH| + BTREE_ITER_ALL_SNAPSHOTS); while ((k = bch2_btree_iter_peek(&iter)).k && !(ret = bkey_err(k))) { @@ -74,7 +75,8 @@ static int __bch2_dev_usrdata_drop(struct bch_fs *c, unsigned dev_idx, int flags bch2_btree_iter_set_pos(&iter, bkey_start_pos(&sk.k->k)); ret = bch2_btree_iter_traverse(&iter) ?: - bch2_trans_update(&trans, &iter, sk.k, 0) ?: + bch2_trans_update(&trans, &iter, sk.k, + BTREE_UPDATE_INTERNAL_SNAPSHOT_NODE) ?: bch2_trans_commit(&trans, NULL, NULL, BTREE_INSERT_NOFAIL); diff --git a/fs/bcachefs/move.c b/fs/bcachefs/move.c index 9dc6684139de5..2e7d8e2fe331d 100644 --- a/fs/bcachefs/move.c +++ b/fs/bcachefs/move.c @@ -14,6 +14,7 @@ #include "keylist.h" #include "move.h" #include "replicas.h" +#include "subvolume.h" #include "super-io.h" #include "trace.h" @@ -52,6 +53,81 @@ struct moving_context { wait_queue_head_t wait; }; +static int insert_snapshot_whiteouts(struct btree_trans *trans, + enum btree_id id, + struct bpos old_pos, + struct bpos new_pos) +{ + struct bch_fs *c = trans->c; + struct btree_iter iter, update_iter; + struct bkey_s_c k; + struct snapshots_seen s; + int ret; + + if (!btree_type_has_snapshots(id)) + return 0; + + snapshots_seen_init(&s); + + if (!bkey_cmp(old_pos, new_pos)) + return 0; + + if (!snapshot_t(c, old_pos.snapshot)->children[0]) + return 0; + + bch2_trans_iter_init(trans, &iter, id, old_pos, + BTREE_ITER_NOT_EXTENTS| + BTREE_ITER_ALL_SNAPSHOTS); + while (1) { +next: + k = bch2_btree_iter_prev(&iter); + ret = bkey_err(k); + if (ret) + break; + + if (bkey_cmp(old_pos, k.k->p)) + break; + + if (bch2_snapshot_is_ancestor(c, k.k->p.snapshot, old_pos.snapshot)) { + struct bkey_i *update; + size_t i; + + for (i = 0; i < s.nr; i++) + if (bch2_snapshot_is_ancestor(c, k.k->p.snapshot, s.d[i])) + goto next; + + update = bch2_trans_kmalloc(trans, sizeof(struct bkey_i)); + + ret = PTR_ERR_OR_ZERO(update); + if (ret) + break; + + bkey_init(&update->k); + update->k.p = new_pos; + update->k.p.snapshot = k.k->p.snapshot; + + bch2_trans_iter_init(trans, &update_iter, id, update->k.p, + BTREE_ITER_NOT_EXTENTS| + BTREE_ITER_ALL_SNAPSHOTS| + BTREE_ITER_INTENT); + ret = bch2_btree_iter_traverse(&update_iter) ?: + bch2_trans_update(trans, &update_iter, update, + BTREE_UPDATE_INTERNAL_SNAPSHOT_NODE); + bch2_trans_iter_exit(trans, &update_iter); + if (ret) + break; + + ret = snapshots_seen_add(c, &s, k.k->p.snapshot); + if (ret) + break; + } + } + bch2_trans_iter_exit(trans, &iter); + kfree(s.d); + + return ret; +} + int bch2_migrate_index_update(struct bch_write_op *op) { struct bch_fs *c = op->c; @@ -165,7 +241,10 @@ int bch2_migrate_index_update(struct bch_write_op *op) next_pos = insert->k.p; - ret = bch2_trans_update(&trans, &iter, insert, 0) ?: + ret = insert_snapshot_whiteouts(&trans, m->btree_id, + k.k->p, insert->k.p) ?: + bch2_trans_update(&trans, &iter, insert, + BTREE_UPDATE_INTERNAL_SNAPSHOT_NODE) ?: bch2_trans_commit(&trans, &op->res, op_journal_seq(op), BTREE_INSERT_NOFAIL| diff --git a/fs/bcachefs/subvolume.h b/fs/bcachefs/subvolume.h index cea4c665af327..0740c7b7f7728 100644 --- a/fs/bcachefs/subvolume.h +++ b/fs/bcachefs/subvolume.h @@ -54,6 +54,44 @@ static inline bool bch2_snapshot_is_ancestor(struct bch_fs *c, u32 id, u32 ances return id == ancestor; } +struct snapshots_seen { + struct bpos pos; + size_t nr; + size_t size; + u32 *d; +}; + +static inline void snapshots_seen_exit(struct snapshots_seen *s) +{ + kfree(s->d); + s->d = NULL; +} + +static inline void snapshots_seen_init(struct snapshots_seen *s) +{ + memset(s, 0, sizeof(*s)); +} + +static inline int snapshots_seen_add(struct bch_fs *c, struct snapshots_seen *s, u32 id) +{ + if (s->nr == s->size) { + size_t new_size = max(s->size, 128UL) * 2; + u32 *d = krealloc(s->d, new_size * sizeof(s->d[0]), GFP_KERNEL); + + if (!d) { + bch_err(c, "error reallocating snapshots_seen table (new size %zu)", + new_size); + return -ENOMEM; + } + + s->size = new_size; + s->d = d; + } + + s->d[s->nr++] = id; + return 0; +} + int bch2_fs_snapshots_check(struct bch_fs *); void bch2_fs_snapshots_exit(struct bch_fs *); int bch2_fs_snapshots_start(struct bch_fs *); -- 2.30.2