bcachefs: Erasure coding now uses backpointers

This is only a start to updating erasure coding for backpointers - it's
still not working yet. The subsequent patch will delete our old in
memory backpointers for copygc, and this fixes a spurious EPERM
bug/error message.

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

diff --git a/fs/bcachefs/ec.c b/fs/bcachefs/ec.c
index af6a23021381cf0f8f29607cc26231b08f939705..68f5314b51e6a31d6edc230e96a78da5153c22c9 100644 (file)
--- a/fs/bcachefs/ec.c
+++ b/fs/bcachefs/ec.c
@@ -4,10 +4,12 @@
 
 #include "bcachefs.h"
 #include "alloc_foreground.h"
+#include "backpointers.h"
 #include "bkey_buf.h"
 #include "bset.h"
 #include "btree_gc.h"
 #include "btree_update.h"
+#include "btree_write_buffer.h"
 #include "buckets.h"
 #include "disk_groups.h"
 #include "ec.h"
@@ -826,21 +828,42 @@ static void extent_stripe_ptr_add(struct bkey_s_extent e,
 }
 
 static int ec_stripe_update_extent(struct btree_trans *trans,
-                                  struct btree_iter *iter,
-                                  struct bkey_s_c k,
+                                  struct bpos bucket, u8 gen,
                                   struct ec_stripe_buf *s,
-                                  struct bpos end)
+                                  u64 *bp_offset)
 {
+       struct bch_fs *c = trans->c;
+       struct bch_backpointer bp;
+       struct btree_iter iter;
+       struct bkey_s_c k;
        const struct bch_extent_ptr *ptr_c;
        struct bch_extent_ptr *ptr, *ec_ptr = NULL;
        struct bkey_i *n;
        int ret, dev, block;
 
-       if (bkey_cmp(bkey_start_pos(k.k), end) >= 0)
-               return 1;
+       ret = bch2_get_next_backpointer(trans, bucket, gen, bp_offset, &bp);
+       if (ret)
+               return ret;
+       if (*bp_offset == U64_MAX)
+               return 0;
 
-       if (extent_has_stripe_ptr(k, s->key.k.p.offset))
+       if (bch2_fs_inconsistent_on(bp.level, c, "found btree node in erasure coded bucket!?"))
+               return -EIO;
+
+       k = bch2_backpointer_get_key(trans, &iter, bucket, *bp_offset, bp);
+       ret = bkey_err(k);
+       if (ret)
+               return ret;
+       if (!k.k) {
+               /*
+                * extent no longer exists - we could flush the btree
+                * write buffer and retry to verify, but no need:
+                */
                return 0;
+       }
+
+       if (extent_has_stripe_ptr(k, s->key.k.p.offset))
+               goto out;
 
        ptr_c = bkey_matches_stripe(&s->key.v, k, &block);
        /*
@@ -848,14 +871,14 @@ static int ec_stripe_update_extent(struct btree_trans *trans,
         * XXX: should we be incrementing a counter?
         */
        if (!ptr_c || ptr_c->cached)
-               return 0;
+               goto out;
 
        dev = s->key.v.ptrs[block].dev;
 
        n = bch2_bkey_make_mut(trans, k);
        ret = PTR_ERR_OR_ZERO(n);
        if (ret)
-               return ret;
+               goto out;
 
        bch2_bkey_drop_ptrs(bkey_i_to_s(n), ptr, ptr->dev != dev);
        ec_ptr = (void *) bch2_bkey_has_device(bkey_i_to_s_c(n), dev);
@@ -863,22 +886,59 @@ static int ec_stripe_update_extent(struct btree_trans *trans,
 
        extent_stripe_ptr_add(bkey_i_to_s_extent(n), s, ec_ptr, block);
 
-       return bch2_trans_update(trans, iter, n, 0);
+       ret = bch2_trans_update(trans, &iter, n, 0);
+out:
+       bch2_trans_iter_exit(trans, &iter);
+       return ret;
 }
 
-static int ec_stripe_update_extents(struct bch_fs *c,
-                                struct ec_stripe_buf *s,
-                                struct bkey *pos)
+static int ec_stripe_update_bucket(struct btree_trans *trans, struct ec_stripe_buf *s,
+                                  unsigned block)
 {
-       struct btree_iter iter;
-       struct bkey_s_c k;
+       struct bch_fs *c = trans->c;
+       struct bch_extent_ptr bucket = s->key.v.ptrs[block];
+       struct bpos bucket_pos = PTR_BUCKET_POS(c, &bucket);
+       u64 bp_offset = 0;
+       int ret = 0;
+
+       while (1) {
+               ret = commit_do(trans, NULL, NULL,
+                               BTREE_INSERT_NOFAIL,
+                       ec_stripe_update_extent(trans, bucket_pos, bucket.gen,
+                                               s, &bp_offset));
+               if (ret)
+                       break;
+               if (bp_offset == U64_MAX)
+                       break;
+
+               bp_offset++;
+       }
+
+       return ret;
+}
+
+static int ec_stripe_update_extents(struct bch_fs *c, struct ec_stripe_buf *s)
+{
+       struct btree_trans trans;
+       struct bch_stripe *v = &s->key.v;
+       unsigned i, nr_data = v->nr_blocks - v->nr_redundant;
+       int ret = 0;
+
+       bch2_trans_init(&trans, c, 0, 0);
 
-       return bch2_trans_run(c,
-               for_each_btree_key_commit(&trans, iter,
-                       BTREE_ID_extents, bkey_start_pos(pos),
-                       BTREE_ITER_NOT_EXTENTS|BTREE_ITER_INTENT, k,
-                       NULL, NULL, BTREE_INSERT_NOFAIL,
-               ec_stripe_update_extent(&trans, &iter, k, s, pos->p)));
+       ret = bch2_btree_write_buffer_flush(&trans);
+       if (ret)
+               goto err;
+
+       for (i = 0; i < nr_data; i++) {
+               ret = ec_stripe_update_bucket(&trans, s, i);
+               if (ret)
+                       break;
+       }
+err:
+       bch2_trans_exit(&trans);
+
+       return ret;
 }
 
 /*
@@ -888,7 +948,6 @@ static void ec_stripe_create(struct ec_stripe_new *s)
 {
        struct bch_fs *c = s->c;
        struct open_bucket *ob;
-       struct bkey_i *k;
        struct stripe *m;
        struct bch_stripe *v = &s->new_stripe.key.v;
        unsigned i, nr_data = v->nr_blocks - v->nr_redundant;
@@ -948,14 +1007,10 @@ static void ec_stripe_create(struct ec_stripe_new *s)
                goto err_put_writes;
        }
 
-       for_each_keylist_key(&s->keys, k) {
-               ret = ec_stripe_update_extents(c, &s->new_stripe, &k->k);
-               if (ret) {
-                       bch_err(c, "error creating stripe: error updating pointers: %s",
-                               bch2_err_str(ret));
-                       break;
-               }
-       }
+       ret = ec_stripe_update_extents(c, &s->new_stripe);
+       if (ret)
+               bch_err(c, "error creating stripe: error updating pointers: %s",
+                       bch2_err_str(ret));
 
        spin_lock(&c->ec_stripes_heap_lock);
        m = genradix_ptr(&c->stripes, s->new_stripe.key.k.p.offset);
@@ -1423,7 +1478,7 @@ static int __bch2_ec_stripe_head_reuse(struct bch_fs *c,
        }
 
        bkey_copy(&h->s->new_stripe.key.k_i,
-                       &h->s->existing_stripe.key.k_i);
+                 &h->s->existing_stripe.key.k_i);
 
        return 0;
 }