]> git.sesse.net Git - bcachefs-tools-debian/blobdiff - libbcachefs/move.c
Update bcachefs sources to 9fc6ccd865 bcachefs: fix copygc_pred()
[bcachefs-tools-debian] / libbcachefs / move.c
index f718f42ad45411c88d3176539658fb7783b83d7f..07d2e2c881dbd8f4be030623c9d33b5224a4c77d 100644 (file)
@@ -3,47 +3,49 @@
 #include "btree_gc.h"
 #include "btree_update.h"
 #include "buckets.h"
+#include "inode.h"
 #include "io.h"
 #include "move.h"
 #include "super-io.h"
 #include "keylist.h"
 
 #include <linux/ioprio.h>
+#include <linux/kthread.h>
 
 #include <trace/events/bcachefs.h>
 
-static struct bch_extent_ptr *bkey_find_ptr(struct bch_fs *c,
-                                           struct bkey_s_extent e,
-                                           struct bch_extent_ptr ptr)
-{
-       struct bch_extent_ptr *ptr2;
-       unsigned bucket_bits = c->devs[ptr.dev]->bucket_bits;
+#define SECTORS_IN_FLIGHT_PER_DEVICE   2048
 
-       extent_for_each_ptr(e, ptr2)
-               if (ptr2->dev == ptr.dev &&
-                   ptr2->gen == ptr.gen &&
-                   (ptr2->offset >> bucket_bits) ==
-                   (ptr.offset >> bucket_bits))
-                       return ptr2;
+struct moving_io {
+       struct list_head        list;
+       struct closure          cl;
+       bool                    read_completed;
 
-       return NULL;
-}
+       unsigned                read_dev;
+       unsigned                read_sectors;
+       unsigned                write_sectors;
 
-static struct bch_extent_ptr *bch2_migrate_matching_ptr(struct migrate_write *m,
-                                                      struct bkey_s_extent e)
-{
-       const struct bch_extent_ptr *ptr;
-       struct bch_extent_ptr *ret;
+       struct bch_read_bio     rbio;
 
-       if (m->move)
-               ret = bkey_find_ptr(m->op.c, e, m->move_ptr);
-       else
-               extent_for_each_ptr(bkey_i_to_s_c_extent(&m->key), ptr)
-                       if ((ret = bkey_find_ptr(m->op.c, e, *ptr)))
-                               break;
+       struct migrate_write    write;
+       /* Must be last since it is variable size */
+       struct bio_vec          bi_inline_vecs[0];
+};
 
-       return ret;
-}
+struct moving_context {
+       /* Closure for waiting on all reads and writes to complete */
+       struct closure          cl;
+
+       struct bch_move_stats   *stats;
+
+       struct list_head        reads;
+
+       /* in flight sectors: */
+       atomic_t                read_sectors[BCH_SB_MEMBERS_MAX];
+       atomic_t                write_sectors;
+
+       wait_queue_head_t       wait;
+};
 
 static int bch2_migrate_index_update(struct bch_write_op *op)
 {
@@ -54,75 +56,120 @@ static int bch2_migrate_index_update(struct bch_write_op *op)
        struct btree_iter iter;
        int ret = 0;
 
-       bch2_btree_iter_init_intent(&iter, c, BTREE_ID_EXTENTS,
-               bkey_start_pos(&bch2_keylist_front(keys)->k));
+       bch2_btree_iter_init(&iter, c, BTREE_ID_EXTENTS,
+                            bkey_start_pos(&bch2_keylist_front(keys)->k),
+                            BTREE_ITER_SLOTS|BTREE_ITER_INTENT);
 
        while (1) {
-               struct bkey_s_extent insert =
-                       bkey_i_to_s_extent(bch2_keylist_front(keys));
-               struct bkey_s_c k = bch2_btree_iter_peek_with_holes(&iter);
+               struct bkey_s_c k = bch2_btree_iter_peek_slot(&iter);
+               struct bkey_i_extent *insert, *new =
+                       bkey_i_to_extent(bch2_keylist_front(keys));
+               BKEY_PADDED(k) _new, _insert;
                struct bch_extent_ptr *ptr;
-               struct bkey_s_extent e;
-               BKEY_PADDED(k) new;
+               struct bch_extent_crc_unpacked crc;
+               bool did_work = false;
+               int nr;
 
-               if (!k.k) {
+               if (btree_iter_err(k)) {
                        ret = bch2_btree_iter_unlock(&iter);
                        break;
                }
 
-               if (!bkey_extent_is_data(k.k))
+               if (bversion_cmp(k.k->version, new->k.version) ||
+                   !bkey_extent_is_data(k.k) ||
+                   !bch2_extent_matches_ptr(c, bkey_s_c_to_extent(k),
+                                            m->ptr, m->offset))
                        goto nomatch;
 
-               bkey_reassemble(&new.k, k);
-               bch2_cut_front(iter.pos, &new.k);
-               bch2_cut_back(insert.k->p, &new.k.k);
-               e = bkey_i_to_s_extent(&new.k);
-
-               /* hack - promotes can race: */
-               if (m->promote)
-                       extent_for_each_ptr(insert, ptr)
-                               if (bch2_extent_has_device(e.c, ptr->dev))
-                                       goto nomatch;
-
-               ptr = bch2_migrate_matching_ptr(m, e);
-               if (ptr) {
-                       int nr_new_dirty = bch2_extent_nr_dirty_ptrs(insert.s_c);
-                       unsigned insert_flags =
-                               BTREE_INSERT_ATOMIC|
-                               BTREE_INSERT_NOFAIL;
+               if (m->data_cmd == DATA_REWRITE &&
+                   !bch2_extent_has_device(bkey_s_c_to_extent(k),
+                                           m->data_opts.rewrite_dev))
+                       goto nomatch;
+
+               bkey_reassemble(&_insert.k, k);
+               insert = bkey_i_to_extent(&_insert.k);
 
-                       /* copygc uses btree node reserve: */
-                       if (m->move)
-                               insert_flags |= BTREE_INSERT_USE_RESERVE;
+               bkey_copy(&_new.k, bch2_keylist_front(keys));
+               new = bkey_i_to_extent(&_new.k);
+
+               bch2_cut_front(iter.pos, &insert->k_i);
+               bch2_cut_back(new->k.p, &insert->k);
+               bch2_cut_back(insert->k.p, &new->k);
+
+               if (m->data_cmd == DATA_REWRITE) {
+                       ptr = (struct bch_extent_ptr *)
+                               bch2_extent_has_device(extent_i_to_s_c(insert),
+                                                      m->data_opts.rewrite_dev);
+                       bch2_extent_drop_ptr(extent_i_to_s(insert), ptr);
+               }
 
-                       if (m->move) {
-                               nr_new_dirty -= !ptr->cached;
-                               __bch2_extent_drop_ptr(e, ptr);
+               extent_for_each_ptr_crc(extent_i_to_s(new), ptr, crc) {
+                       if (bch2_extent_has_device(extent_i_to_s_c(insert), ptr->dev)) {
+                               /*
+                                * raced with another move op? extent already
+                                * has a pointer to the device we just wrote
+                                * data to
+                                */
+                               continue;
                        }
 
-                       BUG_ON(nr_new_dirty < 0);
+                       bch2_extent_crc_append(insert, crc);
+                       extent_ptr_append(insert, *ptr);
+                       did_work = true;
+               }
 
-                       memcpy_u64s(extent_entry_last(e),
-                                   insert.v,
-                                   bkey_val_u64s(insert.k));
-                       e.k->u64s += bkey_val_u64s(insert.k);
+               if (!did_work)
+                       goto nomatch;
 
-                       bch2_extent_narrow_crcs(e);
-                       bch2_extent_drop_redundant_crcs(e);
-                       bch2_extent_normalize(c, e.s);
-                       bch2_extent_mark_replicas_cached(c, e, nr_new_dirty);
+               bch2_extent_narrow_crcs(insert,
+                               (struct bch_extent_crc_unpacked) { 0 });
+               bch2_extent_normalize(c, extent_i_to_s(insert).s);
+               bch2_extent_mark_replicas_cached(c, extent_i_to_s(insert),
+                                                op->opts.background_target,
+                                                op->opts.data_replicas);
+
+               /*
+                * It's possible we race, and for whatever reason the extent now
+                * has fewer replicas than when we last looked at it - meaning
+                * we need to get a disk reservation here:
+                */
+               nr = bch2_extent_nr_dirty_ptrs(bkey_i_to_s_c(&insert->k_i)) -
+                       (bch2_extent_nr_dirty_ptrs(k) + m->nr_ptrs_reserved);
+               if (nr > 0) {
+                       /*
+                        * can't call bch2_disk_reservation_add() with btree
+                        * locks held, at least not without a song and dance
+                        */
+                       bch2_btree_iter_unlock(&iter);
+
+                       ret = bch2_disk_reservation_add(c, &op->res,
+                                       keylist_sectors(keys) * nr, 0);
+                       if (ret)
+                               goto out;
 
-                       ret = bch2_btree_insert_at(c, &op->res,
-                                       NULL, op_journal_seq(op),
-                                       insert_flags,
-                                       BTREE_INSERT_ENTRY(&iter, &new.k));
-                       if (ret && ret != -EINTR)
-                               break;
-               } else {
-nomatch:
-                       bch2_btree_iter_advance_pos(&iter);
+                       m->nr_ptrs_reserved += nr;
+                       goto next;
                }
 
+               ret = bch2_mark_bkey_replicas(c, BCH_DATA_USER,
+                                             extent_i_to_s_c(insert).s_c);
+               if (ret)
+                       break;
+
+               ret = bch2_btree_insert_at(c, &op->res,
+                               NULL, op_journal_seq(op),
+                               BTREE_INSERT_ATOMIC|
+                               BTREE_INSERT_NOFAIL|
+                               BTREE_INSERT_USE_RESERVE|
+                               m->data_opts.btree_insert_flags,
+                               BTREE_INSERT_ENTRY(&iter, &insert->k_i));
+               if (!ret)
+                       atomic_long_inc(&c->extent_migrate_done);
+               if (ret == -EINTR)
+                       ret = 0;
+               if (ret)
+                       break;
+next:
                while (bkey_cmp(iter.pos, bch2_keylist_front(keys)->k.p) >= 0) {
                        bch2_keylist_pop_front(keys);
                        if (bch2_keylist_empty(keys))
@@ -130,104 +177,143 @@ nomatch:
                }
 
                bch2_cut_front(iter.pos, bch2_keylist_front(keys));
+               continue;
+nomatch:
+               if (m->ctxt)
+                       atomic64_add(k.k->p.offset - iter.pos.offset,
+                                    &m->ctxt->stats->sectors_raced);
+               atomic_long_inc(&c->extent_migrate_raced);
+               trace_move_race(&new->k);
+               bch2_btree_iter_next_slot(&iter);
+               goto next;
        }
 out:
        bch2_btree_iter_unlock(&iter);
        return ret;
 }
 
-void bch2_migrate_write_init(struct bch_fs *c,
-                           struct migrate_write *m,
-                           struct write_point *wp,
-                           struct bkey_s_c k,
-                           const struct bch_extent_ptr *move_ptr,
-                           unsigned flags)
+void bch2_migrate_read_done(struct migrate_write *m, struct bch_read_bio *rbio)
 {
-       bkey_reassemble(&m->key, k);
+       /* write bio must own pages: */
+       BUG_ON(!m->op.wbio.bio.bi_vcnt);
+
+       m->ptr          = rbio->pick.ptr;
+       m->offset       = rbio->pos.offset - rbio->pick.crc.offset;
+       m->op.devs_have = rbio->devs_have;
+       m->op.pos       = rbio->pos;
+       m->op.version   = rbio->version;
+       m->op.crc       = rbio->pick.crc;
+       m->op.wbio.bio.bi_iter.bi_size = m->op.crc.compressed_size << 9;
+
+       if (bch2_csum_type_is_encryption(m->op.crc.csum_type)) {
+               m->op.nonce     = m->op.crc.nonce + m->op.crc.offset;
+               m->op.csum_type = m->op.crc.csum_type;
+       }
 
-       m->promote = false;
-       m->move = move_ptr != NULL;
-       if (move_ptr)
-               m->move_ptr = *move_ptr;
+       if (m->data_cmd == DATA_REWRITE)
+               bch2_dev_list_drop_dev(&m->op.devs_have, m->data_opts.rewrite_dev);
+}
+
+int bch2_migrate_write_init(struct bch_fs *c, struct migrate_write *m,
+                           struct write_point_specifier wp,
+                           struct bch_io_opts io_opts,
+                           enum data_cmd data_cmd,
+                           struct data_opts data_opts,
+                           struct bkey_s_c k)
+{
+       int ret;
 
-       if (bkey_extent_is_cached(k.k) ||
-           (move_ptr && move_ptr->cached))
-               flags |= BCH_WRITE_CACHED;
+       m->data_cmd     = data_cmd;
+       m->data_opts    = data_opts;
+       m->nr_ptrs_reserved = 0;
 
-       bch2_write_op_init(&m->op, c, &m->wbio,
-                         (struct disk_reservation) { 0 },
-                         wp,
-                         bkey_start_pos(k.k),
-                         NULL, flags);
+       bch2_write_op_init(&m->op, c, io_opts);
+       m->op.compression_type =
+               bch2_compression_opt_to_type[io_opts.background_compression ?:
+                                            io_opts.compression];
+       m->op.target    = data_opts.target,
+       m->op.write_point = wp;
 
-       if (m->move)
+       if (m->data_opts.btree_insert_flags & BTREE_INSERT_USE_RESERVE)
                m->op.alloc_reserve = RESERVE_MOVINGGC;
 
-       m->op.nonce             = extent_current_nonce(bkey_s_c_to_extent(k));
+       m->op.flags |= BCH_WRITE_ONLY_SPECIFIED_DEVS|
+               BCH_WRITE_PAGES_STABLE|
+               BCH_WRITE_PAGES_OWNED|
+               BCH_WRITE_DATA_ENCODED|
+               BCH_WRITE_NOMARK_REPLICAS;
+
        m->op.nr_replicas       = 1;
+       m->op.nr_replicas_required = 1;
        m->op.index_update_fn   = bch2_migrate_index_update;
-}
 
-static void migrate_bio_init(struct moving_io *io, struct bio *bio,
-                            unsigned sectors)
-{
-       bio_init(bio);
-       bio_set_prio(bio, IOPRIO_PRIO_VALUE(IOPRIO_CLASS_IDLE, 0));
-
-       bio->bi_iter.bi_size    = sectors << 9;
-       bio->bi_max_vecs        = DIV_ROUND_UP(sectors, PAGE_SECTORS);
-       bio->bi_private         = &io->cl;
-       bio->bi_io_vec          = io->bi_inline_vecs;
-       bch2_bio_map(bio, NULL);
+       switch (data_cmd) {
+       case DATA_ADD_REPLICAS: {
+               int nr = (int) io_opts.data_replicas -
+                       bch2_extent_nr_dirty_ptrs(k);
+
+               if (nr > 0) {
+                       m->op.nr_replicas = m->nr_ptrs_reserved = nr;
+
+                       ret = bch2_disk_reservation_get(c, &m->op.res,
+                                       k.k->size, m->op.nr_replicas, 0);
+                       if (ret)
+                               return ret;
+               }
+               break;
+       }
+       case DATA_REWRITE:
+               break;
+       case DATA_PROMOTE:
+               m->op.flags     |= BCH_WRITE_ALLOC_NOWAIT;
+               m->op.flags     |= BCH_WRITE_CACHED;
+               break;
+       default:
+               BUG();
+       }
+
+       return 0;
 }
 
-static void moving_io_destructor(struct closure *cl)
+static void move_free(struct closure *cl)
 {
        struct moving_io *io = container_of(cl, struct moving_io, cl);
-       struct moving_context *ctxt = io->ctxt;
+       struct moving_context *ctxt = io->write.ctxt;
        struct bio_vec *bv;
        int i;
 
-       //if (io->replace.failures)
-       //      trace_copy_collision(q, &io->key.k);
+       bch2_disk_reservation_put(io->write.op.c, &io->write.op.res);
 
-       atomic_sub(io->write.key.k.size, &ctxt->sectors_in_flight);
-       wake_up(&ctxt->wait);
-
-       bio_for_each_segment_all(bv, &io->write.wbio.bio, i)
+       bio_for_each_segment_all(bv, &io->write.op.wbio.bio, i)
                if (bv->bv_page)
                        __free_page(bv->bv_page);
 
-       kfree(io);
-}
+       wake_up(&ctxt->wait);
 
-static void moving_error(struct moving_context *ctxt, unsigned flag)
-{
-       atomic_inc(&ctxt->error_count);
-       //atomic_or(flag, &ctxt->error_flags);
+       kfree(io);
 }
 
-static void moving_io_after_write(struct closure *cl)
+static void move_write_done(struct closure *cl)
 {
        struct moving_io *io = container_of(cl, struct moving_io, cl);
-       struct moving_context *ctxt = io->ctxt;
-
-       if (io->write.op.error)
-               moving_error(ctxt, MOVING_FLAG_WRITE);
 
-       moving_io_destructor(cl);
+       atomic_sub(io->write_sectors, &io->write.ctxt->write_sectors);
+       closure_return_with_destructor(cl, move_free);
 }
 
-static void write_moving(struct moving_io *io)
+static void move_write(struct closure *cl)
 {
-       struct bch_write_op *op = &io->write.op;
+       struct moving_io *io = container_of(cl, struct moving_io, cl);
 
-       if (op->error) {
-               closure_return_with_destructor(&io->cl, moving_io_destructor);
-       } else {
-               closure_call(&op->cl, bch2_write, NULL, &io->cl);
-               closure_return_with_destructor(&io->cl, moving_io_after_write);
+       if (likely(!io->rbio.bio.bi_status)) {
+               bch2_migrate_read_done(&io->write, &io->rbio);
+
+               atomic_add(io->write_sectors, &io->write.ctxt->write_sectors);
+               closure_call(&io->write.op.cl, bch2_write, NULL, cl);
+               continue_at(cl, move_write_done, NULL);
        }
+
+       closure_return_with_destructor(cl, move_free);
 }
 
 static inline struct moving_io *next_pending_write(struct moving_context *ctxt)
@@ -238,155 +324,441 @@ static inline struct moving_io *next_pending_write(struct moving_context *ctxt)
        return io && io->read_completed ? io : NULL;
 }
 
-static void read_moving_endio(struct bio *bio)
+static void move_read_endio(struct bio *bio)
 {
-       struct closure *cl = bio->bi_private;
-       struct moving_io *io = container_of(cl, struct moving_io, cl);
-       struct moving_context *ctxt = io->ctxt;
-
-       trace_move_read_done(&io->write.key.k);
-
-       if (bio->bi_error) {
-               io->write.op.error = bio->bi_error;
-               moving_error(io->ctxt, MOVING_FLAG_READ);
-       }
+       struct moving_io *io = container_of(bio, struct moving_io, rbio.bio);
+       struct moving_context *ctxt = io->write.ctxt;
 
+       atomic_sub(io->read_sectors, &ctxt->read_sectors[io->read_dev]);
        io->read_completed = true;
+
        if (next_pending_write(ctxt))
                wake_up(&ctxt->wait);
 
        closure_put(&ctxt->cl);
 }
 
-static void __bch2_data_move(struct closure *cl)
+static void do_pending_writes(struct moving_context *ctxt)
+{
+       struct moving_io *io;
+
+       while ((io = next_pending_write(ctxt))) {
+               list_del(&io->list);
+               closure_call(&io->cl, move_write, NULL, &ctxt->cl);
+       }
+}
+
+#define move_ctxt_wait_event(_ctxt, _cond)                     \
+do {                                                           \
+       do_pending_writes(_ctxt);                               \
+                                                               \
+       if (_cond)                                              \
+               break;                                          \
+       __wait_event((_ctxt)->wait,                             \
+                    next_pending_write(_ctxt) || (_cond));     \
+} while (1)
+
+static void bch2_move_ctxt_wait_for_io(struct moving_context *ctxt)
+{
+       unsigned sectors_pending = atomic_read(&ctxt->write_sectors);
+
+       move_ctxt_wait_event(ctxt,
+               !atomic_read(&ctxt->write_sectors) ||
+               atomic_read(&ctxt->write_sectors) != sectors_pending);
+}
+
+static int bch2_move_extent(struct bch_fs *c,
+                           struct moving_context *ctxt,
+                           struct write_point_specifier wp,
+                           struct bch_io_opts io_opts,
+                           struct bkey_s_c_extent e,
+                           enum data_cmd data_cmd,
+                           struct data_opts data_opts)
 {
-       struct moving_io *io = container_of(cl, struct moving_io, cl);
-       struct bch_fs *c = io->write.op.c;
        struct extent_pick_ptr pick;
+       struct moving_io *io;
+       const struct bch_extent_ptr *ptr;
+       struct bch_extent_crc_unpacked crc;
+       unsigned sectors = e.k->size, pages;
+       int ret = -ENOMEM;
+
+       move_ctxt_wait_event(ctxt,
+               atomic_read(&ctxt->write_sectors) <
+               SECTORS_IN_FLIGHT_PER_DEVICE);
 
-       bch2_extent_pick_ptr_avoiding(c, bkey_i_to_s_c(&io->write.key),
-                                    io->ctxt->avoid, &pick);
+       bch2_extent_pick_ptr(c, e.s_c, NULL, &pick);
        if (IS_ERR_OR_NULL(pick.ca))
-               closure_return_with_destructor(cl, moving_io_destructor);
+               return pick.ca ? PTR_ERR(pick.ca) : 0;
+
+       move_ctxt_wait_event(ctxt,
+               atomic_read(&ctxt->read_sectors[pick.ca->dev_idx]) <
+               SECTORS_IN_FLIGHT_PER_DEVICE);
+
+       /* write path might have to decompress data: */
+       extent_for_each_ptr_crc(e, ptr, crc)
+               sectors = max_t(unsigned, sectors, crc.uncompressed_size);
+
+       pages = DIV_ROUND_UP(sectors, PAGE_SECTORS);
+       io = kzalloc(sizeof(struct moving_io) +
+                    sizeof(struct bio_vec) * pages, GFP_KERNEL);
+       if (!io)
+               goto err;
+
+       io->write.ctxt          = ctxt;
+       io->read_dev            = pick.ca->dev_idx;
+       io->read_sectors        = pick.crc.uncompressed_size;
+       io->write_sectors       = e.k->size;
+
+       bio_init(&io->write.op.wbio.bio, io->bi_inline_vecs, pages);
+       bio_set_prio(&io->write.op.wbio.bio,
+                    IOPRIO_PRIO_VALUE(IOPRIO_CLASS_IDLE, 0));
+       io->write.op.wbio.bio.bi_iter.bi_size = sectors << 9;
+
+       bch2_bio_map(&io->write.op.wbio.bio, NULL);
+       if (bio_alloc_pages(&io->write.op.wbio.bio, GFP_KERNEL))
+               goto err_free;
+
+       io->rbio.opts = io_opts;
+       bio_init(&io->rbio.bio, io->bi_inline_vecs, pages);
+       bio_set_prio(&io->rbio.bio, IOPRIO_PRIO_VALUE(IOPRIO_CLASS_IDLE, 0));
+       io->rbio.bio.bi_iter.bi_size = sectors << 9;
 
        bio_set_op_attrs(&io->rbio.bio, REQ_OP_READ, 0);
-       io->rbio.bio.bi_iter.bi_sector = bkey_start_offset(&io->write.key.k);
-       io->rbio.bio.bi_end_io  = read_moving_endio;
+       io->rbio.bio.bi_iter.bi_sector  = bkey_start_offset(e.k);
+       io->rbio.bio.bi_end_io          = move_read_endio;
+
+       ret = bch2_migrate_write_init(c, &io->write, wp, io_opts,
+                                     data_cmd, data_opts, e.s_c);
+       if (ret)
+               goto err_free_pages;
+
+       atomic64_inc(&ctxt->stats->keys_moved);
+       atomic64_add(e.k->size, &ctxt->stats->sectors_moved);
+
+       trace_move_extent(e.k);
+
+       atomic_add(io->read_sectors, &ctxt->read_sectors[io->read_dev]);
+       list_add_tail(&io->list, &ctxt->reads);
 
        /*
-        * dropped by read_moving_endio() - guards against use after free of
+        * dropped by move_read_endio() - guards against use after free of
         * ctxt when doing wakeup
         */
-       closure_get(&io->ctxt->cl);
-
-       bch2_read_extent(c, &io->rbio,
-                       bkey_i_to_s_c(&io->write.key),
-                       &pick, BCH_READ_IS_LAST);
+       closure_get(&ctxt->cl);
+       bch2_read_extent(c, &io->rbio, e, &pick, BCH_READ_NODECODE);
+       return 0;
+err_free_pages:
+       bio_free_pages(&io->write.op.wbio.bio);
+err_free:
+       kfree(io);
+err:
+       percpu_ref_put(&pick.ca->io_ref);
+       trace_move_alloc_fail(e.k);
+       return ret;
 }
 
-int bch2_data_move(struct bch_fs *c,
-                 struct moving_context *ctxt,
-                 struct write_point *wp,
-                 struct bkey_s_c k,
-                 const struct bch_extent_ptr *move_ptr)
+int bch2_move_data(struct bch_fs *c,
+                  struct bch_ratelimit *rate,
+                  struct write_point_specifier wp,
+                  struct bpos start,
+                  struct bpos end,
+                  move_pred_fn pred, void *arg,
+                  struct bch_move_stats *stats)
 {
-       struct moving_io *io;
+       bool kthread = (current->flags & PF_KTHREAD) != 0;
+       struct moving_context ctxt = { .stats = stats };
+       struct bch_io_opts io_opts = bch2_opts_to_inode_opts(c->opts);
+       BKEY_PADDED(k) tmp;
+       struct bkey_s_c k;
+       struct bkey_s_c_extent e;
+       struct data_opts data_opts;
+       enum data_cmd data_cmd;
+       u64 cur_inum = U64_MAX;
+       int ret = 0, ret2;
+
+       closure_init_stack(&ctxt.cl);
+       INIT_LIST_HEAD(&ctxt.reads);
+       init_waitqueue_head(&ctxt.wait);
+
+       stats->data_type = BCH_DATA_USER;
+       bch2_btree_iter_init(&stats->iter, c, BTREE_ID_EXTENTS, start,
+                            BTREE_ITER_PREFETCH);
+
+       if (rate)
+               bch2_ratelimit_reset(rate);
+
+       while (!kthread || !(ret = kthread_should_stop())) {
+               if (rate &&
+                   bch2_ratelimit_delay(rate) &&
+                   (bch2_btree_iter_unlock(&stats->iter),
+                    (ret = bch2_ratelimit_wait_freezable_stoppable(rate))))
+                       break;
+peek:
+               k = bch2_btree_iter_peek(&stats->iter);
+               if (!k.k)
+                       break;
+               ret = btree_iter_err(k);
+               if (ret)
+                       break;
+               if (bkey_cmp(bkey_start_pos(k.k), end) >= 0)
+                       break;
 
-       io = kzalloc(sizeof(struct moving_io) + sizeof(struct bio_vec) *
-                    DIV_ROUND_UP(k.k->size, PAGE_SECTORS),
-                    GFP_KERNEL);
-       if (!io)
-               return -ENOMEM;
+               if (!bkey_extent_is_data(k.k))
+                       goto next_nondata;
 
-       io->ctxt = ctxt;
+               e = bkey_s_c_to_extent(k);
 
-       migrate_bio_init(io, &io->rbio.bio, k.k->size);
+               if (cur_inum != k.k->p.inode) {
+                       struct bch_inode_unpacked inode;
 
-       if (bio_alloc_pages(&io->rbio.bio, GFP_KERNEL)) {
-               kfree(io);
-               return -ENOMEM;
-       }
+                       /* don't hold btree locks while looking up inode: */
+                       bch2_btree_iter_unlock(&stats->iter);
 
-       migrate_bio_init(io, &io->write.wbio.bio, k.k->size);
-       bio_get(&io->write.wbio.bio);
-       io->write.wbio.bio.bi_iter.bi_sector = bkey_start_offset(k.k);
+                       io_opts = bch2_opts_to_inode_opts(c->opts);
+                       if (!bch2_inode_find_by_inum(c, k.k->p.inode, &inode))
+                               bch2_io_opts_apply(&io_opts, bch2_inode_opts_get(&inode));
+                       cur_inum = k.k->p.inode;
+                       goto peek;
+               }
 
-       bch2_migrate_write_init(c, &io->write, wp, k, move_ptr, 0);
+               switch ((data_cmd = pred(c, arg, BKEY_TYPE_EXTENTS, e,
+                                        &io_opts, &data_opts))) {
+               case DATA_SKIP:
+                       goto next;
+               case DATA_SCRUB:
+                       BUG();
+               case DATA_ADD_REPLICAS:
+               case DATA_REWRITE:
+               case DATA_PROMOTE:
+                       break;
+               default:
+                       BUG();
+               }
 
-       trace_move_read(&io->write.key.k);
+               /* unlock before doing IO: */
+               bkey_reassemble(&tmp.k, k);
+               k = bkey_i_to_s_c(&tmp.k);
+               bch2_btree_iter_unlock(&stats->iter);
+
+               ret2 = bch2_move_extent(c, &ctxt, wp, io_opts,
+                                       bkey_s_c_to_extent(k),
+                                       data_cmd, data_opts);
+               if (ret2) {
+                       if (ret2 == -ENOMEM) {
+                               /* memory allocation failure, wait for some IO to finish */
+                               bch2_move_ctxt_wait_for_io(&ctxt);
+                               continue;
+                       }
 
-       ctxt->keys_moved++;
-       ctxt->sectors_moved += k.k->size;
-       if (ctxt->rate)
-               bch2_ratelimit_increment(ctxt->rate, k.k->size);
+                       /* XXX signal failure */
+                       goto next;
+               }
 
-       atomic_add(k.k->size, &ctxt->sectors_in_flight);
-       list_add_tail(&io->list, &ctxt->reads);
+               if (rate)
+                       bch2_ratelimit_increment(rate, k.k->size);
+next:
+               atomic64_add(k.k->size * bch2_extent_nr_dirty_ptrs(k),
+                            &stats->sectors_seen);
+next_nondata:
+               bch2_btree_iter_next(&stats->iter);
+               bch2_btree_iter_cond_resched(&stats->iter);
+       }
 
-       closure_call(&io->cl, __bch2_data_move, NULL, &ctxt->cl);
-       return 0;
+       bch2_btree_iter_unlock(&stats->iter);
+
+       move_ctxt_wait_event(&ctxt, list_empty(&ctxt.reads));
+       closure_sync(&ctxt.cl);
+
+       EBUG_ON(atomic_read(&ctxt.write_sectors));
+
+       trace_move_data(c,
+                       atomic64_read(&stats->sectors_moved),
+                       atomic64_read(&stats->keys_moved));
+
+       return ret;
 }
 
-static void do_pending_writes(struct moving_context *ctxt)
+static int bch2_gc_data_replicas(struct bch_fs *c)
 {
-       struct moving_io *io;
+       struct btree_iter iter;
+       struct bkey_s_c k;
+       int ret;
 
-       while ((io = next_pending_write(ctxt))) {
-               list_del(&io->list);
-               trace_move_write(&io->write.key.k);
-               write_moving(io);
+       mutex_lock(&c->replicas_gc_lock);
+       bch2_replicas_gc_start(c, (1 << BCH_DATA_USER)|(1 << BCH_DATA_CACHED));
+
+       for_each_btree_key(&iter, c, BTREE_ID_EXTENTS, POS_MIN,
+                          BTREE_ITER_PREFETCH, k) {
+               ret = bch2_mark_bkey_replicas(c, BCH_DATA_USER, k);
+               if (ret)
+                       break;
        }
+       ret = bch2_btree_iter_unlock(&iter) ?: ret;
+
+       bch2_replicas_gc_end(c, ret);
+       mutex_unlock(&c->replicas_gc_lock);
+
+       return ret;
 }
 
-#define move_ctxt_wait_event(_ctxt, _cond)                     \
-do {                                                           \
-       do_pending_writes(_ctxt);                               \
-                                                               \
-       if (_cond)                                              \
-               break;                                          \
-       __wait_event((_ctxt)->wait,                             \
-                    next_pending_write(_ctxt) || (_cond));     \
-} while (1)
+static int bch2_gc_btree_replicas(struct bch_fs *c)
+{
+       struct btree_iter iter;
+       struct btree *b;
+       unsigned id;
+       int ret = 0;
+
+       mutex_lock(&c->replicas_gc_lock);
+       bch2_replicas_gc_start(c, 1 << BCH_DATA_BTREE);
+
+       for (id = 0; id < BTREE_ID_NR; id++) {
+               for_each_btree_node(&iter, c, id, POS_MIN, BTREE_ITER_PREFETCH, b) {
+                       ret = bch2_mark_bkey_replicas(c, BCH_DATA_BTREE,
+                                                     bkey_i_to_s_c(&b->key));
+
+                       bch2_btree_iter_cond_resched(&iter);
+               }
+
+               ret = bch2_btree_iter_unlock(&iter) ?: ret;
+       }
+
+       bch2_replicas_gc_end(c, ret);
+       mutex_unlock(&c->replicas_gc_lock);
 
-int bch2_move_ctxt_wait(struct moving_context *ctxt)
+       return ret;
+}
+
+static int bch2_move_btree(struct bch_fs *c,
+                          move_pred_fn pred,
+                          void *arg,
+                          struct bch_move_stats *stats)
 {
-       move_ctxt_wait_event(ctxt,
-                            atomic_read(&ctxt->sectors_in_flight) <
-                            ctxt->max_sectors_in_flight);
+       struct bch_io_opts io_opts = bch2_opts_to_inode_opts(c->opts);
+       struct btree *b;
+       unsigned id;
+       struct data_opts data_opts;
+       enum data_cmd cmd;
+       int ret = 0;
+
+       stats->data_type = BCH_DATA_BTREE;
+
+       for (id = 0; id < BTREE_ID_NR; id++) {
+               for_each_btree_node(&stats->iter, c, id, POS_MIN, BTREE_ITER_PREFETCH, b) {
+                       switch ((cmd = pred(c, arg, BKEY_TYPE_BTREE,
+                                           bkey_i_to_s_c_extent(&b->key),
+                                           &io_opts,
+                                           &data_opts))) {
+                       case DATA_SKIP:
+                               goto next;
+                       case DATA_SCRUB:
+                               BUG();
+                       case DATA_ADD_REPLICAS:
+                       case DATA_REWRITE:
+                               break;
+                       default:
+                               BUG();
+                       }
+
+                       ret = bch2_btree_node_rewrite(c, &stats->iter,
+                                       b->data->keys.seq, 0) ?: ret;
+next:
+                       bch2_btree_iter_cond_resched(&stats->iter);
+               }
+
+               ret = bch2_btree_iter_unlock(&stats->iter) ?: ret;
+       }
+
+       return ret;
+}
 
-       return ctxt->rate
-               ? bch2_ratelimit_wait_freezable_stoppable(ctxt->rate)
-               : 0;
+#if 0
+static enum data_cmd scrub_pred(struct bch_fs *c, void *arg,
+                               enum bkey_type type,
+                               struct bkey_s_c_extent e,
+                               struct bch_io_opts *io_opts,
+                               struct data_opts *data_opts)
+{
+       return DATA_SCRUB;
 }
+#endif
 
-void bch2_move_ctxt_wait_for_io(struct moving_context *ctxt)
+static enum data_cmd rereplicate_pred(struct bch_fs *c, void *arg,
+                                     enum bkey_type type,
+                                     struct bkey_s_c_extent e,
+                                     struct bch_io_opts *io_opts,
+                                     struct data_opts *data_opts)
 {
-       unsigned sectors_pending = atomic_read(&ctxt->sectors_in_flight);
+       unsigned nr_good = bch2_extent_durability(c, e);
+       unsigned replicas = type == BKEY_TYPE_BTREE
+               ? c->opts.metadata_replicas
+               : io_opts->data_replicas;
 
-       move_ctxt_wait_event(ctxt,
-               !atomic_read(&ctxt->sectors_in_flight) ||
-               atomic_read(&ctxt->sectors_in_flight) != sectors_pending);
+       if (!nr_good || nr_good >= replicas)
+               return DATA_SKIP;
+
+       data_opts->target               = 0;
+       data_opts->btree_insert_flags = 0;
+       return DATA_ADD_REPLICAS;
 }
 
-void bch2_move_ctxt_exit(struct moving_context *ctxt)
+static enum data_cmd migrate_pred(struct bch_fs *c, void *arg,
+                                 enum bkey_type type,
+                                 struct bkey_s_c_extent e,
+                                 struct bch_io_opts *io_opts,
+                                 struct data_opts *data_opts)
 {
-       move_ctxt_wait_event(ctxt, !atomic_read(&ctxt->sectors_in_flight));
-       closure_sync(&ctxt->cl);
+       struct bch_ioctl_data *op = arg;
+
+       if (!bch2_extent_has_device(e, op->migrate.dev))
+               return DATA_SKIP;
 
-       EBUG_ON(!list_empty(&ctxt->reads));
-       EBUG_ON(atomic_read(&ctxt->sectors_in_flight));
+       data_opts->target               = 0;
+       data_opts->btree_insert_flags   = 0;
+       data_opts->rewrite_dev          = op->migrate.dev;
+       return DATA_REWRITE;
 }
 
-void bch2_move_ctxt_init(struct moving_context *ctxt,
-                       struct bch_ratelimit *rate,
-                       unsigned max_sectors_in_flight)
+int bch2_data_job(struct bch_fs *c,
+                 struct bch_move_stats *stats,
+                 struct bch_ioctl_data op)
 {
-       memset(ctxt, 0, sizeof(*ctxt));
-       closure_init_stack(&ctxt->cl);
+       int ret = 0;
 
-       ctxt->rate = rate;
-       ctxt->max_sectors_in_flight = max_sectors_in_flight;
+       switch (op.op) {
+       case BCH_DATA_OP_REREPLICATE:
+               stats->data_type = BCH_DATA_JOURNAL;
+               ret = bch2_journal_flush_device(&c->journal, -1);
+
+               ret = bch2_move_btree(c, rereplicate_pred, c, stats) ?: ret;
+               ret = bch2_gc_btree_replicas(c) ?: ret;
+
+               ret = bch2_move_data(c, NULL,
+                                    writepoint_hashed((unsigned long) current),
+                                    op.start,
+                                    op.end,
+                                    rereplicate_pred, c, stats) ?: ret;
+               ret = bch2_gc_data_replicas(c) ?: ret;
+               break;
+       case BCH_DATA_OP_MIGRATE:
+               if (op.migrate.dev >= c->sb.nr_devices)
+                       return -EINVAL;
+
+               stats->data_type = BCH_DATA_JOURNAL;
+               ret = bch2_journal_flush_device(&c->journal, op.migrate.dev);
+
+               ret = bch2_move_btree(c, migrate_pred, &op, stats) ?: ret;
+               ret = bch2_gc_btree_replicas(c) ?: ret;
+
+               ret = bch2_move_data(c, NULL,
+                                    writepoint_hashed((unsigned long) current),
+                                    op.start,
+                                    op.end,
+                                    migrate_pred, &op, stats) ?: ret;
+               ret = bch2_gc_data_replicas(c) ?: ret;
+               break;
+       default:
+               ret = -EINVAL;
+       }
 
-       INIT_LIST_HEAD(&ctxt->reads);
-       init_waitqueue_head(&ctxt->wait);
+       return ret;
 }