]> git.sesse.net Git - bcachefs-tools-debian/blobdiff - libbcachefs/reflink.c
Merge pull request #211 from oz123/master
[bcachefs-tools-debian] / libbcachefs / reflink.c
index 2f223be74926bc5f67725a8d578970d6491a9598..c47c66c2b394dc8df391fa3adf8bfea03e1e447e 100644 (file)
@@ -1,24 +1,47 @@
 // SPDX-License-Identifier: GPL-2.0
 #include "bcachefs.h"
-#include "bkey_on_stack.h"
+#include "bkey_buf.h"
 #include "btree_update.h"
+#include "buckets.h"
+#include "error.h"
 #include "extents.h"
 #include "inode.h"
-#include "io.h"
+#include "io_misc.h"
+#include "io_write.h"
+#include "rebalance.h"
 #include "reflink.h"
+#include "subvolume.h"
+#include "super-io.h"
 
 #include <linux/sched/signal.h>
 
+static inline unsigned bkey_type_to_indirect(const struct bkey *k)
+{
+       switch (k->type) {
+       case KEY_TYPE_extent:
+               return KEY_TYPE_reflink_v;
+       case KEY_TYPE_inline_data:
+               return KEY_TYPE_indirect_inline_data;
+       default:
+               return 0;
+       }
+}
+
 /* reflink pointers */
 
-const char *bch2_reflink_p_invalid(const struct bch_fs *c, struct bkey_s_c k)
+int bch2_reflink_p_invalid(struct bch_fs *c, struct bkey_s_c k,
+                          enum bkey_invalid_flags flags,
+                          struct printbuf *err)
 {
        struct bkey_s_c_reflink_p p = bkey_s_c_to_reflink_p(k);
+       int ret = 0;
 
-       if (bkey_val_bytes(p.k) != sizeof(*p.v))
-               return "incorrect value size";
-
-       return NULL;
+       bkey_fsck_err_on(le64_to_cpu(p.v->idx) < le32_to_cpu(p.v->front_pad),
+                        c, err, reflink_p_front_pad_bad,
+                        "idx < front_pad (%llu < %u)",
+                        le64_to_cpu(p.v->idx), le32_to_cpu(p.v->front_pad));
+fsck_err:
+       return ret;
 }
 
 void bch2_reflink_p_to_text(struct printbuf *out, struct bch_fs *c,
@@ -26,39 +49,215 @@ 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);
 
-       pr_buf(out, "idx %llu", le64_to_cpu(p.v->idx));
+       prt_printf(out, "idx %llu front_pad %u back_pad %u",
+              le64_to_cpu(p.v->idx),
+              le32_to_cpu(p.v->front_pad),
+              le32_to_cpu(p.v->back_pad));
 }
 
-enum merge_result bch2_reflink_p_merge(struct bch_fs *c,
-                                      struct bkey_s _l, struct bkey_s _r)
+bool bch2_reflink_p_merge(struct bch_fs *c, struct bkey_s _l, struct bkey_s_c _r)
 {
        struct bkey_s_reflink_p l = bkey_s_to_reflink_p(_l);
-       struct bkey_s_reflink_p r = bkey_s_to_reflink_p(_r);
+       struct bkey_s_c_reflink_p r = bkey_s_c_to_reflink_p(_r);
+
+       /*
+        * Disabled for now, the triggers code needs to be reworked for merging
+        * of reflink pointers to work:
+        */
+       return false;
 
        if (le64_to_cpu(l.v->idx) + l.k->size != le64_to_cpu(r.v->idx))
-               return BCH_MERGE_NOMERGE;
+               return false;
+
+       bch2_key_resize(l.k, l.k->size + r.k->size);
+       return true;
+}
+
+static int trans_trigger_reflink_p_segment(struct btree_trans *trans,
+                       struct bkey_s_c_reflink_p p,
+                       u64 *idx, unsigned flags)
+{
+       struct bch_fs *c = trans->c;
+       struct btree_iter iter;
+       struct bkey_i *k;
+       __le64 *refcount;
+       int add = !(flags & BTREE_TRIGGER_OVERWRITE) ? 1 : -1;
+       struct printbuf buf = PRINTBUF;
+       int ret;
 
-       if ((u64) l.k->size + r.k->size > KEY_SIZE_MAX) {
-               bch2_key_resize(l.k, KEY_SIZE_MAX);
-               bch2_cut_front_s(l.k->p, _r);
-               return BCH_MERGE_PARTIAL;
+       k = bch2_bkey_get_mut_noupdate(trans, &iter,
+                       BTREE_ID_reflink, POS(0, *idx),
+                       BTREE_ITER_WITH_UPDATES);
+       ret = PTR_ERR_OR_ZERO(k);
+       if (ret)
+               goto err;
+
+       refcount = bkey_refcount(bkey_i_to_s(k));
+       if (!refcount) {
+               bch2_bkey_val_to_text(&buf, c, p.s_c);
+               bch2_trans_inconsistent(trans,
+                       "nonexistent indirect extent at %llu while marking\n  %s",
+                       *idx, buf.buf);
+               ret = -EIO;
+               goto err;
        }
 
-       bch2_key_resize(l.k, l.k->size + r.k->size);
+       if (!*refcount && (flags & BTREE_TRIGGER_OVERWRITE)) {
+               bch2_bkey_val_to_text(&buf, c, p.s_c);
+               bch2_trans_inconsistent(trans,
+                       "indirect extent refcount underflow at %llu while marking\n  %s",
+                       *idx, buf.buf);
+               ret = -EIO;
+               goto err;
+       }
+
+       if (flags & BTREE_TRIGGER_INSERT) {
+               struct bch_reflink_p *v = (struct bch_reflink_p *) p.v;
+               u64 pad;
+
+               pad = max_t(s64, le32_to_cpu(v->front_pad),
+                           le64_to_cpu(v->idx) - bkey_start_offset(&k->k));
+               BUG_ON(pad > U32_MAX);
+               v->front_pad = cpu_to_le32(pad);
 
-       return BCH_MERGE_MERGE;
+               pad = max_t(s64, le32_to_cpu(v->back_pad),
+                           k->k.p.offset - p.k->size - le64_to_cpu(v->idx));
+               BUG_ON(pad > U32_MAX);
+               v->back_pad = cpu_to_le32(pad);
+       }
+
+       le64_add_cpu(refcount, add);
+
+       bch2_btree_iter_set_pos_to_extent_start(&iter);
+       ret = bch2_trans_update(trans, &iter, k, 0);
+       if (ret)
+               goto err;
+
+       *idx = k->k.p.offset;
+err:
+       bch2_trans_iter_exit(trans, &iter);
+       printbuf_exit(&buf);
+       return ret;
 }
 
-/* indirect extents */
+static s64 gc_trigger_reflink_p_segment(struct btree_trans *trans,
+                               struct bkey_s_c_reflink_p p,
+                               u64 *idx, unsigned flags, size_t r_idx)
+{
+       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 next_idx = end + le32_to_cpu(p.v->back_pad);
+       s64 ret = 0;
+       struct printbuf buf = PRINTBUF;
+
+       if (r_idx >= c->reflink_gc_nr)
+               goto not_found;
+
+       r = genradix_ptr(&c->reflink_gc_table, r_idx);
+       next_idx = min(next_idx, r->offset - r->size);
+       if (*idx < next_idx)
+               goto not_found;
+
+       BUG_ON((s64) r->refcount + add < 0);
+
+       r->refcount += add;
+       *idx = r->offset;
+       return 0;
+not_found:
+       if (fsck_err(c, reflink_p_to_missing_reflink_v,
+                    "pointer to missing indirect extent\n"
+                    "  %s\n"
+                    "  missing range %llu-%llu",
+                    (bch2_bkey_val_to_text(&buf, c, p.s_c), buf.buf),
+                    *idx, next_idx)) {
+               struct bkey_i *update = bch2_bkey_make_mut_noupdate(trans, p.s_c);
+               ret = PTR_ERR_OR_ZERO(update);
+               if (ret)
+                       goto err;
 
-const char *bch2_reflink_v_invalid(const struct bch_fs *c, struct bkey_s_c k)
+               if (next_idx <= start) {
+                       bkey_i_to_reflink_p(update)->v.front_pad = cpu_to_le32(start - next_idx);
+               } else if (*idx >= end) {
+                       bkey_i_to_reflink_p(update)->v.back_pad = cpu_to_le32(*idx - end);
+               } else {
+                       bkey_error_init(update);
+                       update->k.p             = p.k->p;
+                       update->k.p.offset      = next_idx;
+                       update->k.size          = next_idx - *idx;
+                       set_bkey_val_u64s(&update->k, 0);
+               }
+
+               ret = bch2_btree_insert_trans(trans, BTREE_ID_extents, update, BTREE_TRIGGER_NORUN);
+       }
+
+       *idx = next_idx;
+err:
+fsck_err:
+       printbuf_exit(&buf);
+       return ret;
+}
+
+static int __trigger_reflink_p(struct btree_trans *trans,
+                           enum btree_id btree_id, unsigned level,
+                           struct bkey_s_c k, unsigned flags)
 {
-       struct bkey_s_c_reflink_v r = bkey_s_c_to_reflink_v(k);
+       struct bch_fs *c = trans->c;
+       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);
+
+       if (flags & BTREE_TRIGGER_TRANSACTIONAL) {
+               while (idx < end && !ret)
+                       ret = trans_trigger_reflink_p_segment(trans, p, &idx, flags);
+       }
+
+       if (flags & BTREE_TRIGGER_GC) {
+               size_t l = 0, r = c->reflink_gc_nr;
 
-       if (bkey_val_bytes(r.k) < sizeof(*r.v))
-               return "incorrect value size";
+               while (l < r) {
+                       size_t m = l + (r - l) / 2;
+                       struct reflink_gc *ref = genradix_ptr(&c->reflink_gc_table, m);
+                       if (ref->offset <= idx)
+                               l = m + 1;
+                       else
+                               r = m;
+               }
+
+               while (idx < end && !ret)
+                       ret = gc_trigger_reflink_p_segment(trans, p, &idx, flags, l++);
+       }
 
-       return bch2_bkey_ptrs_invalid(c, k);
+       return ret;
+}
+
+int bch2_trigger_reflink_p(struct btree_trans *trans,
+                          enum btree_id btree_id, unsigned level,
+                          struct bkey_s_c old,
+                          struct bkey_s new,
+                          unsigned flags)
+{
+       if ((flags & BTREE_TRIGGER_TRANSACTIONAL) &&
+           (flags & BTREE_TRIGGER_INSERT)) {
+               struct bch_reflink_p *v = bkey_s_to_reflink_p(new).v;
+
+               v->front_pad = v->back_pad = 0;
+       }
+
+       return trigger_run_overwrite_then_insert(__trigger_reflink_p, trans, btree_id, level, old, new, flags);
+}
+
+/* indirect extents */
+
+int bch2_reflink_v_invalid(struct bch_fs *c, struct bkey_s_c k,
+                          enum bkey_invalid_flags flags,
+                          struct printbuf *err)
+{
+       return bch2_bkey_ptrs_invalid(c, k, flags, err);
 }
 
 void bch2_reflink_v_to_text(struct printbuf *out, struct bch_fs *c,
@@ -66,166 +265,262 @@ void bch2_reflink_v_to_text(struct printbuf *out, struct bch_fs *c,
 {
        struct bkey_s_c_reflink_v r = bkey_s_c_to_reflink_v(k);
 
-       pr_buf(out, "refcount: %llu ", le64_to_cpu(r.v->refcount));
+       prt_printf(out, "refcount: %llu ", le64_to_cpu(r.v->refcount));
 
        bch2_bkey_ptrs_to_text(out, c, k);
 }
 
+#if 0
+Currently disabled, needs to be debugged:
+
+bool bch2_reflink_v_merge(struct bch_fs *c, struct bkey_s _l, struct bkey_s_c _r)
+{
+       struct bkey_s_reflink_v   l = bkey_s_to_reflink_v(_l);
+       struct bkey_s_c_reflink_v r = bkey_s_c_to_reflink_v(_r);
+
+       return l.v->refcount == r.v->refcount && bch2_extent_merge(c, _l, _r);
+}
+#endif
+
+static inline void check_indirect_extent_deleting(struct bkey_s new, unsigned *flags)
+{
+       if ((*flags & BTREE_TRIGGER_INSERT) && !*bkey_refcount(new)) {
+               new.k->type = KEY_TYPE_deleted;
+               new.k->size = 0;
+               set_bkey_val_u64s(new.k, 0);
+               *flags &= ~BTREE_TRIGGER_INSERT;
+       }
+}
+
+int bch2_trigger_reflink_v(struct btree_trans *trans,
+                          enum btree_id btree_id, unsigned level,
+                          struct bkey_s_c old, struct bkey_s new,
+                          unsigned flags)
+{
+       if ((flags & BTREE_TRIGGER_TRANSACTIONAL) &&
+           (flags & BTREE_TRIGGER_INSERT))
+               check_indirect_extent_deleting(new, &flags);
+
+       return bch2_trigger_extent(trans, btree_id, level, old, new, flags);
+}
+
+/* indirect inline data */
+
+int bch2_indirect_inline_data_invalid(struct bch_fs *c, struct bkey_s_c k,
+                                     enum bkey_invalid_flags flags,
+                                     struct printbuf *err)
+{
+       return 0;
+}
+
+void bch2_indirect_inline_data_to_text(struct printbuf *out,
+                                      struct bch_fs *c, struct bkey_s_c k)
+{
+       struct bkey_s_c_indirect_inline_data d = bkey_s_c_to_indirect_inline_data(k);
+       unsigned datalen = bkey_inline_data_bytes(k.k);
+
+       prt_printf(out, "refcount %llu datalen %u: %*phN",
+              le64_to_cpu(d.v->refcount), datalen,
+              min(datalen, 32U), d.v->data);
+}
+
+int bch2_trigger_indirect_inline_data(struct btree_trans *trans,
+                             enum btree_id btree_id, unsigned level,
+                             struct bkey_s_c old, struct bkey_s new,
+                             unsigned flags)
+{
+       check_indirect_extent_deleting(new, &flags);
+
+       return 0;
+}
+
 static int bch2_make_extent_indirect(struct btree_trans *trans,
                                     struct btree_iter *extent_iter,
-                                    struct bkey_i_extent *e)
+                                    struct bkey_i *orig)
 {
        struct bch_fs *c = trans->c;
-       struct btree_iter *reflink_iter;
+       struct btree_iter reflink_iter = { NULL };
        struct bkey_s_c k;
-       struct bkey_i_reflink_v *r_v;
+       struct bkey_i *r_v;
        struct bkey_i_reflink_p *r_p;
+       __le64 *refcount;
        int ret;
 
-       for_each_btree_key(trans, reflink_iter, BTREE_ID_REFLINK,
-                          POS(0, c->reflink_hint),
-                          BTREE_ITER_INTENT|BTREE_ITER_SLOTS, k, ret) {
-               if (reflink_iter->pos.inode) {
-                       bch2_btree_iter_set_pos(reflink_iter, POS_MIN);
-                       continue;
-               }
-
-               if (bkey_deleted(k.k) && e->k.size <= k.k->size)
-                       break;
-       }
+       if (orig->k.type == KEY_TYPE_inline_data)
+               bch2_check_set_feature(c, BCH_FEATURE_reflink_inline_data);
 
+       bch2_trans_iter_init(trans, &reflink_iter, BTREE_ID_reflink, POS_MAX,
+                            BTREE_ITER_INTENT);
+       k = bch2_btree_iter_peek_prev(&reflink_iter);
+       ret = bkey_err(k);
        if (ret)
                goto err;
 
-       /* rewind iter to start of hole, if necessary: */
-       bch2_btree_iter_set_pos(reflink_iter, bkey_start_pos(k.k));
-
-       r_v = bch2_trans_kmalloc(trans, sizeof(*r_v) + bkey_val_bytes(&e->k));
+       r_v = bch2_trans_kmalloc(trans, sizeof(__le64) + bkey_bytes(&orig->k));
        ret = PTR_ERR_OR_ZERO(r_v);
        if (ret)
                goto err;
 
-       bkey_reflink_v_init(&r_v->k_i);
-       r_v->k.p        = reflink_iter->pos;
-       bch2_key_resize(&r_v->k, e->k.size);
-       r_v->k.version  = e->k.version;
+       bkey_init(&r_v->k);
+       r_v->k.type     = bkey_type_to_indirect(&orig->k);
+       r_v->k.p        = reflink_iter.pos;
+       bch2_key_resize(&r_v->k, orig->k.size);
+       r_v->k.version  = orig->k.version;
 
-       set_bkey_val_u64s(&r_v->k, bkey_val_u64s(&r_v->k) +
-                         bkey_val_u64s(&e->k));
-       r_v->v.refcount = 0;
-       memcpy(r_v->v.start, e->v.start, bkey_val_bytes(&e->k));
+       set_bkey_val_bytes(&r_v->k, sizeof(__le64) + bkey_val_bytes(&orig->k));
 
-       bch2_trans_update(trans, reflink_iter, &r_v->k_i, 0);
+       refcount        = bkey_refcount(bkey_i_to_s(r_v));
+       *refcount       = 0;
+       memcpy(refcount + 1, &orig->v, bkey_val_bytes(&orig->k));
 
-       r_p = bch2_trans_kmalloc(trans, sizeof(*r_p));
-       if (IS_ERR(r_p))
-               return PTR_ERR(r_p);
+       ret = bch2_trans_update(trans, &reflink_iter, r_v, 0);
+       if (ret)
+               goto err;
 
-       e->k.type = KEY_TYPE_reflink_p;
-       r_p = bkey_i_to_reflink_p(&e->k_i);
+       /*
+        * orig is in a bkey_buf which statically allocates 5 64s for the val,
+        * so we know it will be big enough:
+        */
+       orig->k.type = KEY_TYPE_reflink_p;
+       r_p = bkey_i_to_reflink_p(orig);
        set_bkey_val_bytes(&r_p->k, sizeof(r_p->v));
+
+       /* FORTIFY_SOURCE is broken here, and doesn't provide unsafe_memset() */
+#if !defined(__NO_FORTIFY) && defined(__OPTIMIZE__) && defined(CONFIG_FORTIFY_SOURCE)
+       __underlying_memset(&r_p->v, 0, sizeof(r_p->v));
+#else
+       memset(&r_p->v, 0, sizeof(r_p->v));
+#endif
+
        r_p->v.idx = cpu_to_le64(bkey_start_offset(&r_v->k));
 
-       bch2_trans_update(trans, extent_iter, &r_p->k_i, 0);
+       ret = bch2_trans_update(trans, extent_iter, &r_p->k_i,
+                               BTREE_UPDATE_INTERNAL_SNAPSHOT_NODE);
 err:
-       if (!IS_ERR(reflink_iter))
-               c->reflink_hint = reflink_iter->pos.offset;
-       bch2_trans_iter_put(trans, reflink_iter);
+       bch2_trans_iter_exit(trans, &reflink_iter);
 
        return ret;
 }
 
 static struct bkey_s_c get_next_src(struct btree_iter *iter, struct bpos end)
 {
-       struct bkey_s_c k = bch2_btree_iter_peek(iter);
+       struct bkey_s_c k;
        int ret;
 
-       for_each_btree_key_continue(iter, 0, k, ret) {
-               if (bkey_cmp(iter->pos, end) >= 0)
-                       return bkey_s_c_null;
+       for_each_btree_key_upto_continue_norestart(*iter, end, 0, k, ret) {
+               if (bkey_extent_is_unwritten(k))
+                       continue;
 
-               if (k.k->type == KEY_TYPE_extent ||
-                   k.k->type == KEY_TYPE_reflink_p)
-                       break;
+               if (bkey_extent_is_data(k.k))
+                       return k;
        }
 
-       return k;
+       if (bkey_ge(iter->pos, end))
+               bch2_btree_iter_set_pos(iter, end);
+       return ret ? bkey_s_c_err(ret) : bkey_s_c_null;
 }
 
 s64 bch2_remap_range(struct bch_fs *c,
-                    struct bpos dst_start, struct bpos src_start,
-                    u64 remap_sectors, u64 *journal_seq,
+                    subvol_inum dst_inum, u64 dst_offset,
+                    subvol_inum src_inum, u64 src_offset,
+                    u64 remap_sectors,
                     u64 new_i_size, s64 *i_sectors_delta)
 {
-       struct btree_trans trans;
-       struct btree_iter *dst_iter, *src_iter;
+       struct btree_trans *trans;
+       struct btree_iter dst_iter, src_iter;
        struct bkey_s_c src_k;
-       BKEY_PADDED(k) new_dst;
-       struct bkey_on_stack new_src;
+       struct bkey_buf new_dst, new_src;
+       struct bpos dst_start = POS(dst_inum.inum, dst_offset);
+       struct bpos src_start = POS(src_inum.inum, src_offset);
        struct bpos dst_end = dst_start, src_end = src_start;
-       struct bpos dst_want, src_want;
-       u64 src_done, dst_done;
+       struct bch_io_opts opts;
+       struct bpos src_want;
+       u64 dst_done = 0;
+       u32 dst_snapshot, src_snapshot;
        int ret = 0, ret2 = 0;
 
-       if (!percpu_ref_tryget(&c->writes))
-               return -EROFS;
+       if (!bch2_write_ref_tryget(c, BCH_WRITE_REF_reflink))
+               return -BCH_ERR_erofs_no_writes;
 
        bch2_check_set_feature(c, BCH_FEATURE_reflink);
 
        dst_end.offset += remap_sectors;
        src_end.offset += remap_sectors;
 
-       bkey_on_stack_init(&new_src);
-       bch2_trans_init(&trans, c, BTREE_ITER_MAX, 4096);
+       bch2_bkey_buf_init(&new_dst);
+       bch2_bkey_buf_init(&new_src);
+       trans = bch2_trans_get(c);
+
+       ret = bch2_inum_opts_get(trans, src_inum, &opts);
+       if (ret)
+               goto err;
 
-       src_iter = bch2_trans_get_iter(&trans, BTREE_ID_EXTENTS, src_start,
-                                      BTREE_ITER_INTENT);
-       dst_iter = bch2_trans_get_iter(&trans, BTREE_ID_EXTENTS, dst_start,
-                                      BTREE_ITER_INTENT);
+       bch2_trans_iter_init(trans, &src_iter, BTREE_ID_extents, src_start,
+                            BTREE_ITER_INTENT);
+       bch2_trans_iter_init(trans, &dst_iter, BTREE_ID_extents, dst_start,
+                            BTREE_ITER_INTENT);
 
-       while (1) {
-               bch2_trans_begin(&trans);
+       while ((ret == 0 ||
+               bch2_err_matches(ret, BCH_ERR_transaction_restart)) &&
+              bkey_lt(dst_iter.pos, dst_end)) {
+               struct disk_reservation disk_res = { 0 };
 
-               trans.mem_top = 0;
+               bch2_trans_begin(trans);
 
                if (fatal_signal_pending(current)) {
                        ret = -EINTR;
-                       goto err;
+                       break;
                }
 
-               src_k = get_next_src(src_iter, src_end);
-               ret = bkey_err(src_k);
+               ret = bch2_subvolume_get_snapshot(trans, src_inum.subvol,
+                                                 &src_snapshot);
                if (ret)
-                       goto btree_err;
+                       continue;
 
-               src_done = bpos_min(src_iter->pos, src_end).offset -
-                       src_start.offset;
-               dst_want = POS(dst_start.inode, dst_start.offset + src_done);
+               bch2_btree_iter_set_snapshot(&src_iter, src_snapshot);
 
-               if (bkey_cmp(dst_iter->pos, dst_want) < 0) {
-                       ret = bch2_fpunch_at(&trans, dst_iter, dst_want,
-                                            journal_seq, i_sectors_delta);
-                       if (ret)
-                               goto btree_err;
+               ret = bch2_subvolume_get_snapshot(trans, dst_inum.subvol,
+                                                 &dst_snapshot);
+               if (ret)
                        continue;
+
+               bch2_btree_iter_set_snapshot(&dst_iter, dst_snapshot);
+
+               if (dst_inum.inum < src_inum.inum) {
+                       /* Avoid some lock cycle transaction restarts */
+                       ret = bch2_btree_iter_traverse(&dst_iter);
+                       if (ret)
+                               continue;
                }
 
-               BUG_ON(bkey_cmp(dst_iter->pos, dst_want));
+               dst_done = dst_iter.pos.offset - dst_start.offset;
+               src_want = POS(src_start.inode, src_start.offset + dst_done);
+               bch2_btree_iter_set_pos(&src_iter, src_want);
 
-               if (!bkey_cmp(dst_iter->pos, dst_end))
-                       break;
+               src_k = get_next_src(&src_iter, src_end);
+               ret = bkey_err(src_k);
+               if (ret)
+                       continue;
 
-               if (src_k.k->type == KEY_TYPE_extent) {
-                       bkey_on_stack_reassemble(&new_src, c, src_k);
-                       src_k = bkey_i_to_s_c(new_src.k);
+               if (bkey_lt(src_want, src_iter.pos)) {
+                       ret = bch2_fpunch_at(trans, &dst_iter, dst_inum,
+                                       min(dst_end.offset,
+                                           dst_iter.pos.offset +
+                                           src_iter.pos.offset - src_want.offset),
+                                       i_sectors_delta);
+                       continue;
+               }
 
-                       bch2_cut_front(src_iter->pos,   new_src.k);
-                       bch2_cut_back(src_end,          new_src.k);
+               if (src_k.k->type != KEY_TYPE_reflink_p) {
+                       bch2_btree_iter_set_pos_to_extent_start(&src_iter);
 
-                       ret = bch2_make_extent_indirect(&trans, src_iter,
-                                               bkey_i_to_extent(new_src.k));
+                       bch2_bkey_buf_reassemble(&new_src, c, src_k);
+                       src_k = bkey_i_to_s_c(new_src.k);
+
+                       ret = bch2_make_extent_indirect(trans, &src_iter,
+                                               new_src.k);
                        if (ret)
-                               goto btree_err;
+                               continue;
 
                        BUG_ON(src_k.k->type != KEY_TYPE_reflink_p);
                }
@@ -234,10 +529,10 @@ s64 bch2_remap_range(struct bch_fs *c,
                        struct bkey_s_c_reflink_p src_p =
                                bkey_s_c_to_reflink_p(src_k);
                        struct bkey_i_reflink_p *dst_p =
-                               bkey_reflink_p_init(&new_dst.k);
+                               bkey_reflink_p_init(new_dst.k);
 
                        u64 offset = le64_to_cpu(src_p.v->idx) +
-                               (src_iter->pos.offset -
+                               (src_want.offset -
                                 bkey_start_offset(src_k.k));
 
                        dst_p->v.idx = cpu_to_le64(offset);
@@ -245,56 +540,52 @@ s64 bch2_remap_range(struct bch_fs *c,
                        BUG();
                }
 
-               new_dst.k.k.p = dst_iter->pos;
-               bch2_key_resize(&new_dst.k.k,
-                               min(src_k.k->p.offset - src_iter->pos.offset,
-                                   dst_end.offset - dst_iter->pos.offset));
-
-               ret = bch2_extent_update(&trans, dst_iter, &new_dst.k,
-                                        NULL, journal_seq,
-                                        new_i_size, i_sectors_delta);
-               if (ret)
-                       goto btree_err;
-
-               dst_done = dst_iter->pos.offset - dst_start.offset;
-               src_want = POS(src_start.inode, src_start.offset + dst_done);
-               bch2_btree_iter_set_pos(src_iter, src_want);
-btree_err:
-               if (ret == -EINTR)
-                       ret = 0;
-               if (ret)
-                       goto err;
+               new_dst.k->k.p = dst_iter.pos;
+               bch2_key_resize(&new_dst.k->k,
+                               min(src_k.k->p.offset - src_want.offset,
+                                   dst_end.offset - dst_iter.pos.offset));
+
+               ret =   bch2_bkey_set_needs_rebalance(c, new_dst.k, &opts) ?:
+                       bch2_extent_update(trans, dst_inum, &dst_iter,
+                                       new_dst.k, &disk_res,
+                                       new_i_size, i_sectors_delta,
+                                       true);
+               bch2_disk_reservation_put(c, &disk_res);
        }
+       bch2_trans_iter_exit(trans, &dst_iter);
+       bch2_trans_iter_exit(trans, &src_iter);
 
-       BUG_ON(bkey_cmp(dst_iter->pos, dst_end));
-err:
-       BUG_ON(bkey_cmp(dst_iter->pos, dst_end) > 0);
-
-       dst_done = dst_iter->pos.offset - dst_start.offset;
-       new_i_size = min(dst_iter->pos.offset << 9, new_i_size);
+       BUG_ON(!ret && !bkey_eq(dst_iter.pos, dst_end));
+       BUG_ON(bkey_gt(dst_iter.pos, dst_end));
 
-       bch2_trans_begin(&trans);
+       dst_done = dst_iter.pos.offset - dst_start.offset;
+       new_i_size = min(dst_iter.pos.offset << 9, new_i_size);
 
        do {
                struct bch_inode_unpacked inode_u;
-               struct btree_iter *inode_iter;
+               struct btree_iter inode_iter = { NULL };
 
-               inode_iter = bch2_inode_peek(&trans, &inode_u,
-                               dst_start.inode, BTREE_ITER_INTENT);
-               ret2 = PTR_ERR_OR_ZERO(inode_iter);
+               bch2_trans_begin(trans);
+
+               ret2 = bch2_inode_peek(trans, &inode_iter, &inode_u,
+                                      dst_inum, BTREE_ITER_INTENT);
 
                if (!ret2 &&
                    inode_u.bi_size < new_i_size) {
                        inode_u.bi_size = new_i_size;
-                       ret2  = bch2_inode_write(&trans, inode_iter, &inode_u) ?:
-                               bch2_trans_commit(&trans, NULL, journal_seq, 0);
+                       ret2  = bch2_inode_write(trans, &inode_iter, &inode_u) ?:
+                               bch2_trans_commit(trans, NULL, NULL,
+                                                 BCH_TRANS_COMMIT_no_enospc);
                }
-       } while (ret2 == -EINTR);
 
-       ret = bch2_trans_exit(&trans) ?: ret;
-       bkey_on_stack_exit(&new_src, c);
+               bch2_trans_iter_exit(trans, &inode_iter);
+       } while (bch2_err_matches(ret2, BCH_ERR_transaction_restart));
+err:
+       bch2_trans_put(trans);
+       bch2_bkey_buf_exit(&new_src, c);
+       bch2_bkey_buf_exit(&new_dst, c);
 
-       percpu_ref_put(&c->writes);
+       bch2_write_ref_put(c, BCH_WRITE_REF_reflink);
 
        return dst_done ?: ret ?: ret2;
 }