bcachefs: Optimize fiemap

Reflink caused fiemap performance to regress badly - this gets us back
to where we were.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

diff --git a/fs/bcachefs/fs.c b/fs/bcachefs/fs.c
index dcaf1da656d198d8e2586ff1381e63c52f66d26c..ffd9b386a14ded08fb5d970d7567afb28ae246b6 100644 (file)
--- a/fs/bcachefs/fs.c
+++ b/fs/bcachefs/fs.c
@@ -1203,6 +1203,7 @@ static int bch2_fiemap(struct inode *vinode, struct fiemap_extent_info *info,
        struct btree_iter *iter;
        struct bkey_s_c k;
        BKEY_PADDED(k) cur, prev;
+       struct bpos end = POS(ei->v.i_ino, (start + len) >> 9);
        unsigned offset_into_extent, sectors;
        bool have_extent = false;
        int ret = 0;
@@ -1217,14 +1218,16 @@ static int bch2_fiemap(struct inode *vinode, struct fiemap_extent_info *info,
        bch2_trans_init(&trans, c, 0, 0);
 
        iter = bch2_trans_get_iter(&trans, BTREE_ID_EXTENTS,
-                                  POS(ei->v.i_ino, start >> 9),
-                                  BTREE_ITER_SLOTS);
-
-       while (bkey_cmp(iter->pos, POS(ei->v.i_ino, (start + len) >> 9)) < 0) {
-               k = bch2_btree_iter_peek_slot(iter);
-               ret = bkey_err(k);
-               if (ret)
-                       goto err;
+                                  POS(ei->v.i_ino, start >> 9), 0);
+retry:
+       while ((k = bch2_btree_iter_peek(iter)).k &&
+              !(ret = bkey_err(k)) &&
+              bkey_cmp(iter->pos, end) < 0) {
+               if (!bkey_extent_is_data(k.k) &&
+                   k.k->type != KEY_TYPE_reservation) {
+                       bch2_btree_iter_next(iter);
+                       continue;
+               }
 
                bkey_reassemble(&cur.k, k);
                k = bkey_i_to_s_c(&cur.k);
@@ -1240,34 +1243,37 @@ static int bch2_fiemap(struct inode *vinode, struct fiemap_extent_info *info,
 
                sectors = min(sectors, k.k->size - offset_into_extent);
 
-               bch2_cut_front(POS(k.k->p.inode,
-                                  bkey_start_offset(k.k) + offset_into_extent),
-                              &cur.k);
+               if (offset_into_extent)
+                       bch2_cut_front(POS(k.k->p.inode,
+                                          bkey_start_offset(k.k) +
+                                          offset_into_extent),
+                                      &cur.k);
                bch2_key_resize(&cur.k.k, sectors);
                cur.k.k.p.offset = iter->pos.offset + cur.k.k.size;
 
-               if (bkey_extent_is_data(k.k) ||
-                   k.k->type == KEY_TYPE_reservation) {
-                       if (have_extent) {
-                               ret = bch2_fill_extent(c, info,
-                                               bkey_i_to_s_c(&prev.k), 0);
-                               if (ret)
-                                       break;
-                       }
-
-                       bkey_copy(&prev.k, &cur.k);
-                       have_extent = true;
+               if (have_extent) {
+                       ret = bch2_fill_extent(c, info,
+                                       bkey_i_to_s_c(&prev.k), 0);
+                       if (ret)
+                               break;
                }
 
-               bch2_btree_iter_set_pos(iter,
-                               POS(iter->pos.inode,
-                                   iter->pos.offset + sectors));
+               bkey_copy(&prev.k, &cur.k);
+               have_extent = true;
+
+               if (k.k->type == KEY_TYPE_reflink_v)
+                       bch2_btree_iter_set_pos(iter, k.k->p);
+               else
+                       bch2_btree_iter_next(iter);
        }
 
+       if (ret == -EINTR)
+               goto retry;
+
        if (!ret && have_extent)
                ret = bch2_fill_extent(c, info, bkey_i_to_s_c(&prev.k),
                                       FIEMAP_EXTENT_LAST);
-err:
+
        ret = bch2_trans_exit(&trans) ?: ret;
        return ret < 0 ? ret : 0;
 }