bcachefs: Don't fragment extents when making them indirect

This fixes a "disk usage increased without a reservation" bug, when
reflinking compressed extents. Also, there's no good reason for reflink
to be fragmenting extents anyways.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

diff --git a/fs/bcachefs/reflink.c b/fs/bcachefs/reflink.c
index e986b5284d374cfaba583db42cb943626bf58f37..a420729288d4200a4ba002038e8348412ce69e55 100644 (file)
--- a/fs/bcachefs/reflink.c
+++ b/fs/bcachefs/reflink.c
@@ -181,18 +181,19 @@ err:
 
 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;
+                       break;
 
                if (bkey_extent_is_data(k.k))
-                       break;
+                       return k;
        }
 
-       return k;
+       bch2_btree_iter_set_pos(iter, end);
+       return bkey_s_c_null;
 }
 
 s64 bch2_remap_range(struct bch_fs *c,
@@ -205,8 +206,8 @@ s64 bch2_remap_range(struct bch_fs *c,
        struct bkey_s_c src_k;
        struct bkey_buf new_dst, new_src;
        struct bpos dst_end = dst_start, src_end = src_start;
-       struct bpos dst_want, src_want;
-       u64 src_done, dst_done;
+       struct bpos src_want;
+       u64 dst_done;
        int ret = 0, ret2 = 0;
 
        if (!percpu_ref_tryget(&c->writes))
@@ -226,7 +227,8 @@ s64 bch2_remap_range(struct bch_fs *c,
        dst_iter = bch2_trans_get_iter(&trans, BTREE_ID_extents, dst_start,
                                       BTREE_ITER_INTENT);
 
-       while (ret == 0 || ret == -EINTR) {
+       while ((ret == 0 || ret == -EINTR) &&
+              bkey_cmp(dst_iter->pos, dst_end) < 0) {
                struct disk_reservation disk_res = { 0 };
 
                bch2_trans_begin(&trans);
@@ -236,32 +238,29 @@ s64 bch2_remap_range(struct bch_fs *c,
                        break;
                }
 
+               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);
+
                src_k = get_next_src(src_iter, src_end);
                ret = bkey_err(src_k);
                if (ret)
                        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);
-
-               if (bkey_cmp(dst_iter->pos, dst_want) < 0) {
-                       ret = bch2_fpunch_at(&trans, dst_iter, dst_want,
-                                            journal_seq, i_sectors_delta);
+               if (bkey_cmp(src_want, src_iter->pos) < 0) {
+                       ret = bch2_fpunch_at(&trans, dst_iter,
+                                       bpos_min(dst_end,
+                                                POS(dst_iter->pos.inode, dst_iter->pos.offset +
+                                                    src_iter->pos.offset - src_want.offset)),
+                                                journal_seq, i_sectors_delta);
                        continue;
                }
 
-               BUG_ON(bkey_cmp(dst_iter->pos, dst_want));
-
-               if (!bkey_cmp(dst_iter->pos, dst_end))
-                       break;
-
                if (src_k.k->type != KEY_TYPE_reflink_p) {
                        bch2_bkey_buf_reassemble(&new_src, c, src_k);
                        src_k = bkey_i_to_s_c(new_src.k);
 
-                       bch2_cut_front(src_iter->pos,   new_src.k);
-                       bch2_cut_back(src_end,          new_src.k);
+                       bch2_btree_iter_set_pos(src_iter, bkey_start_pos(src_k.k));
 
                        ret = bch2_make_extent_indirect(&trans, src_iter,
                                                new_src.k);
@@ -278,7 +277,7 @@ s64 bch2_remap_range(struct bch_fs *c,
                                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);
@@ -288,20 +287,13 @@ s64 bch2_remap_range(struct bch_fs *c,
 
                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,
+                               min(src_k.k->p.offset - src_want.offset,
                                    dst_end.offset - dst_iter->pos.offset));
-
                ret = bch2_extent_update(&trans, dst_iter, new_dst.k,
                                         &disk_res, journal_seq,
                                         new_i_size, i_sectors_delta,
                                         true);
                bch2_disk_reservation_put(c, &disk_res);
-               if (ret)
-                       continue;
-
-               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);
        }
        bch2_trans_iter_put(&trans, dst_iter);
        bch2_trans_iter_put(&trans, src_iter);