bcachefs: Subvolumes, snapshots

This patch adds subvolume.c - support for the subvolumes and snapshots
btrees and related data types and on disk data structures. The next
patches will start hooking up this new code to existing code.

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

1 files changed, 13 insertions, 2 deletions

diff --git a/fs/bcachefs/inode.c b/fs/bcachefs/inode.c
index 2b653ee03f4f..3b19dc6b9ddc 100644
--- a/fs/bcachefs/inode.c
+++ b/fs/bcachefs/inode.c
@@ -8,6 +8,7 @@
 #include "extents.h"
 #include "inode.h"
 #include "str_hash.h"
+#include "subvolume.h"
 #include "varint.h"
 
 #include <linux/random.h>
@@ -340,8 +341,8 @@ int bch2_inode_write(struct btree_trans *trans,
 
 const char *bch2_inode_invalid(const struct bch_fs *c, struct bkey_s_c k)
 {
-		struct bkey_s_c_inode inode = bkey_s_c_to_inode(k);
-		struct bch_inode_unpacked unpacked;
+	struct bkey_s_c_inode inode = bkey_s_c_to_inode(k);
+	struct bch_inode_unpacked unpacked;
 
 	if (k.k->p.inode)
 		return "nonzero k.p.inode";
@@ -368,6 +369,9 @@ const char *bch2_inode_invalid(const struct bch_fs *c, struct bkey_s_c k)
 	    unpacked.bi_nlink != 0)
 		return "flagged as unlinked but bi_nlink != 0";
 
+	if (unpacked.bi_subvol && !S_ISDIR(unpacked.bi_mode))
+		return "subvolume root but not a directory";
+
 	return NULL;
 }
 
@@ -635,6 +639,13 @@ retry:
 
 	bch2_inode_unpack(bkey_s_c_to_inode(k), &inode_u);
 
+	/* Subvolume root? */
+	if (inode_u.bi_subvol) {
+		ret = bch2_subvolume_delete(&trans, inode_u.bi_subvol, -1);
+		if (ret)
+			goto err;
+	}
+
 	bkey_inode_generation_init(&delete.k_i);
 	delete.k.p = iter.pos;
 	delete.v.bi_generation = cpu_to_le32(inode_u.bi_generation + 1);