bcachefs: Fix quotas + snapshots

Now that we can reliably designate and find the master subvolume out of
a tree of snapshots, we can finally make quotas work with snapshots:

That is - quotas will now _ignore_ snapshot subvolumes, and only be in
effect for the master (non snapshot) subvolume.

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

1 files changed, 14 insertions, 11 deletions

diff --git a/fs/bcachefs/quota.c b/fs/bcachefs/quota.c
index 7734e0dfe523..310eb9d26571 100644
--- a/fs/bcachefs/quota.c
+++ b/fs/bcachefs/quota.c
@@ -2,6 +2,7 @@
 #include "bcachefs.h"
 #include "btree_update.h"
 #include "errcode.h"
+#include "error.h"
 #include "inode.h"
 #include "quota.h"
 #include "subvolume.h"
@@ -556,23 +557,25 @@ static int bch2_fs_quota_read_inode(struct btree_trans *trans,
 {
 	struct bch_fs *c = trans->c;
 	struct bch_inode_unpacked u;
-	struct bch_subvolume subvolume;
+	struct bch_snapshot_tree s_t;
 	int ret;
 
-	ret = bch2_snapshot_get_subvol(trans, k.k->p.snapshot, &subvolume);
+	ret = bch2_snapshot_tree_lookup(trans,
+			snapshot_t(c, k.k->p.snapshot)->tree, &s_t);
+	bch2_fs_inconsistent_on(bch2_err_matches(ret, ENOENT), c,
+			"%s: snapshot tree %u not found", __func__,
+			snapshot_t(c, k.k->p.snapshot)->tree);
 	if (ret)
 		return ret;
 
-	/*
-	 * We don't do quota accounting in snapshots:
-	 */
-	if (BCH_SUBVOLUME_SNAP(&subvolume))
+	if (!s_t.master_subvol)
 		goto advance;
 
-	if (!bkey_is_inode(k.k))
-		goto advance;
-
-	ret = bch2_inode_unpack(k, &u);
+	ret = bch2_inode_find_by_inum_trans(trans,
+				(subvol_inum) {
+					le32_to_cpu(s_t.master_subvol),
+					k.k->p.offset,
+				}, &u);
 	if (ret)
 		return ret;
 
@@ -581,7 +584,7 @@ static int bch2_fs_quota_read_inode(struct btree_trans *trans,
 	bch2_quota_acct(c, bch_qid(&u), Q_INO, 1,
 			KEY_TYPE_QUOTA_NOCHECK);
 advance:
-	bch2_btree_iter_set_pos(iter, POS(iter->pos.inode, iter->pos.offset + 1));
+	bch2_btree_iter_set_pos(iter, bpos_nosnap_successor(iter->pos));
 	return 0;
 }