bcachefs: Split out snapshot.c

subvolume.c has gotten a bit large, this splits out a separate file just
for managing snapshot trees - BTREE_ID_snapshots.

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

fs/bcachefs/Makefile

@@ -69,6 +69,7 @@ bcachefs-y		:=	\
 	sb-members.o		\
 	siphash.o		\
 	six.o			\
+	snapshot.o		\
 	subvolume.o		\
 	super.o			\
 	super-io.o		\

fs/bcachefs/bcachefs_format.h

@@ -1124,6 +1124,11 @@ struct bch_subvolume {
 	__le32			flags;
 	__le32			snapshot;
 	__le64			inode;
+	/*
+	 * Snapshot subvolumes form a tree, separate from the snapshot nodes
+	 * tree - if this subvolume is a snapshot, this is the ID of the
+	 * subvolume it was created from:
+	 */
 	__le32			parent;
 	__le32			pad;
 	bch_le128		otime;

fs/bcachefs/bkey_methods.c

@@ -13,6 +13,7 @@
 #include "lru.h"
 #include "quota.h"
 #include "reflink.h"
+#include "snapshot.h"
 #include "subvolume.h"
 #include "xattr.h"
 

fs/bcachefs/btree_iter.c

@@ -14,7 +14,7 @@
 #include "extents.h"
 #include "journal.h"
 #include "replicas.h"
-#include "subvolume.h"
+#include "snapshot.h"
 #include "trace.h"
 
 #include <linux/random.h>

fs/bcachefs/btree_trans_commit.c

@@ -14,7 +14,7 @@
 #include "journal.h"
 #include "journal_reclaim.h"
 #include "replicas.h"
-#include "subvolume.h"
+#include "snapshot.h"
 
 #include <linux/prefetch.h>
 

fs/bcachefs/btree_update.c

@@ -11,7 +11,7 @@
 #include "error.h"
 #include "extents.h"
 #include "keylist.h"
-#include "subvolume.h"
+#include "snapshot.h"
 #include "trace.h"
 
 static inline int btree_insert_entry_cmp(const struct btree_insert_entry *l,

fs/bcachefs/fs.c

@@ -23,6 +23,7 @@
 #include "journal.h"
 #include "keylist.h"
 #include "quota.h"
+#include "snapshot.h"
 #include "super.h"
 #include "xattr.h"
 

fs/bcachefs/fsck.c

@@ -12,7 +12,7 @@
 #include "inode.h"
 #include "keylist.h"
 #include "recovery.h"
-#include "subvolume.h"
+#include "snapshot.h"
 #include "super.h"
 #include "xattr.h"
 

fs/bcachefs/inode.c

@@ -11,6 +11,7 @@
 #include "extent_update.h"
 #include "inode.h"
 #include "str_hash.h"
+#include "snapshot.h"
 #include "subvolume.h"
 #include "varint.h"
 

fs/bcachefs/quota.c

@@ -5,7 +5,7 @@
 #include "error.h"
 #include "inode.h"
 #include "quota.h"
-#include "subvolume.h"
+#include "snapshot.h"
 #include "super-io.h"
 
 static const char * const bch2_quota_types[] = {

fs/bcachefs/recovery.c

@@ -25,6 +25,7 @@
 #include "recovery.h"
 #include "replicas.h"
 #include "sb-clean.h"
+#include "snapshot.h"
 #include "subvolume.h"
 #include "super-io.h"
 

fs/bcachefs/snapshot.h

@@ -0,0 +1,256 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _BCACHEFS_SNAPSHOT_H
+#define _BCACHEFS_SNAPSHOT_H
+
+enum bkey_invalid_flags;
+
+void bch2_snapshot_tree_to_text(struct printbuf *, struct bch_fs *, struct bkey_s_c);
+int bch2_snapshot_tree_invalid(const struct bch_fs *, struct bkey_s_c,
+			       enum bkey_invalid_flags, struct printbuf *);
+
+#define bch2_bkey_ops_snapshot_tree ((struct bkey_ops) {	\
+	.key_invalid	= bch2_snapshot_tree_invalid,		\
+	.val_to_text	= bch2_snapshot_tree_to_text,		\
+	.min_val_size	= 8,					\
+})
+
+struct bkey_i_snapshot_tree *__bch2_snapshot_tree_create(struct btree_trans *);
+
+int bch2_snapshot_tree_lookup(struct btree_trans *, u32, struct bch_snapshot_tree *);
+
+void bch2_snapshot_to_text(struct printbuf *, struct bch_fs *, struct bkey_s_c);
+int bch2_snapshot_invalid(const struct bch_fs *, struct bkey_s_c,
+			  enum bkey_invalid_flags, struct printbuf *);
+int bch2_mark_snapshot(struct btree_trans *, enum btree_id, unsigned,
+		       struct bkey_s_c, struct bkey_s_c, unsigned);
+
+#define bch2_bkey_ops_snapshot ((struct bkey_ops) {		\
+	.key_invalid	= bch2_snapshot_invalid,		\
+	.val_to_text	= bch2_snapshot_to_text,		\
+	.atomic_trigger	= bch2_mark_snapshot,			\
+	.min_val_size	= 24,					\
+})
+
+static inline struct snapshot_t *__snapshot_t(struct snapshot_table *t, u32 id)
+{
+	return &t->s[U32_MAX - id];
+}
+
+static inline const struct snapshot_t *snapshot_t(struct bch_fs *c, u32 id)
+{
+	return __snapshot_t(rcu_dereference(c->snapshots), id);
+}
+
+static inline u32 bch2_snapshot_tree(struct bch_fs *c, u32 id)
+{
+	rcu_read_lock();
+	id = snapshot_t(c, id)->tree;
+	rcu_read_unlock();
+
+	return id;
+}
+
+static inline u32 __bch2_snapshot_parent_early(struct bch_fs *c, u32 id)
+{
+	return snapshot_t(c, id)->parent;
+}
+
+static inline u32 bch2_snapshot_parent_early(struct bch_fs *c, u32 id)
+{
+	rcu_read_lock();
+	id = __bch2_snapshot_parent_early(c, id);
+	rcu_read_unlock();
+
+	return id;
+}
+
+static inline u32 __bch2_snapshot_parent(struct bch_fs *c, u32 id)
+{
+#ifdef CONFIG_BCACHEFS_DEBUG
+	u32 parent = snapshot_t(c, id)->parent;
+
+	if (parent &&
+	    snapshot_t(c, id)->depth != snapshot_t(c, parent)->depth + 1)
+		panic("id %u depth=%u parent %u depth=%u\n",
+		      id, snapshot_t(c, id)->depth,
+		      parent, snapshot_t(c, parent)->depth);
+
+	return parent;
+#else
+	return snapshot_t(c, id)->parent;
+#endif
+}
+
+static inline u32 bch2_snapshot_parent(struct bch_fs *c, u32 id)
+{
+	rcu_read_lock();
+	id = __bch2_snapshot_parent(c, id);
+	rcu_read_unlock();
+
+	return id;
+}
+
+static inline u32 bch2_snapshot_nth_parent(struct bch_fs *c, u32 id, u32 n)
+{
+	rcu_read_lock();
+	while (n--)
+		id = __bch2_snapshot_parent(c, id);
+	rcu_read_unlock();
+
+	return id;
+}
+
+u32 bch2_snapshot_skiplist_get(struct bch_fs *, u32);
+
+static inline u32 bch2_snapshot_root(struct bch_fs *c, u32 id)
+{
+	u32 parent;
+
+	rcu_read_lock();
+	while ((parent = __bch2_snapshot_parent(c, id)))
+		id = parent;
+	rcu_read_unlock();
+
+	return id;
+}
+
+static inline u32 __bch2_snapshot_equiv(struct bch_fs *c, u32 id)
+{
+	return snapshot_t(c, id)->equiv;
+}
+
+static inline u32 bch2_snapshot_equiv(struct bch_fs *c, u32 id)
+{
+	rcu_read_lock();
+	id = __bch2_snapshot_equiv(c, id);
+	rcu_read_unlock();
+
+	return id;
+}
+
+static inline bool bch2_snapshot_is_equiv(struct bch_fs *c, u32 id)
+{
+	return id == bch2_snapshot_equiv(c, id);
+}
+
+static inline bool bch2_snapshot_is_internal_node(struct bch_fs *c, u32 id)
+{
+	const struct snapshot_t *s;
+	bool ret;
+
+	rcu_read_lock();
+	s = snapshot_t(c, id);
+	ret = s->children[0];
+	rcu_read_unlock();
+
+	return ret;
+}
+
+static inline u32 bch2_snapshot_is_leaf(struct bch_fs *c, u32 id)
+{
+	return !bch2_snapshot_is_internal_node(c, id);
+}
+
+static inline u32 bch2_snapshot_sibling(struct bch_fs *c, u32 id)
+{
+	const struct snapshot_t *s;
+	u32 parent = __bch2_snapshot_parent(c, id);
+
+	if (!parent)
+		return 0;
+
+	s = snapshot_t(c, __bch2_snapshot_parent(c, id));
+	if (id == s->children[0])
+		return s->children[1];
+	if (id == s->children[1])
+		return s->children[0];
+	return 0;
+}
+
+static inline u32 bch2_snapshot_depth(struct bch_fs *c, u32 parent)
+{
+	u32 depth;
+
+	rcu_read_lock();
+	depth = parent ? snapshot_t(c, parent)->depth + 1 : 0;
+	rcu_read_unlock();
+
+	return depth;
+}
+
+bool __bch2_snapshot_is_ancestor(struct bch_fs *, u32, u32);
+
+static inline bool bch2_snapshot_is_ancestor(struct bch_fs *c, u32 id, u32 ancestor)
+{
+	return id == ancestor
+		? true
+		: __bch2_snapshot_is_ancestor(c, id, ancestor);
+}
+
+static inline bool bch2_snapshot_has_children(struct bch_fs *c, u32 id)
+{
+	const struct snapshot_t *t;
+	bool ret;
+
+	rcu_read_lock();
+	t = snapshot_t(c, id);
+	ret = (t->children[0]|t->children[1]) != 0;
+	rcu_read_unlock();
+
+	return ret;
+}
+
+static inline bool snapshot_list_has_id(snapshot_id_list *s, u32 id)
+{
+	u32 *i;
+
+	darray_for_each(*s, i)
+		if (*i == id)
+			return true;
+	return false;
+}
+
+static inline bool snapshot_list_has_ancestor(struct bch_fs *c, snapshot_id_list *s, u32 id)
+{
+	u32 *i;
+
+	darray_for_each(*s, i)
+		if (bch2_snapshot_is_ancestor(c, id, *i))
+			return true;
+	return false;
+}
+
+static inline int snapshot_list_add(struct bch_fs *c, snapshot_id_list *s, u32 id)
+{
+	int ret;
+
+	BUG_ON(snapshot_list_has_id(s, id));
+	ret = darray_push(s, id);
+	if (ret)
+		bch_err(c, "error reallocating snapshot_id_list (size %zu)", s->size);
+	return ret;
+}
+
+int bch2_snapshot_lookup(struct btree_trans *trans, u32 id,
+			 struct bch_snapshot *s);
+int bch2_snapshot_get_subvol(struct btree_trans *, u32,
+			     struct bch_subvolume *);
+int bch2_snapshot_live(struct btree_trans *trans, u32 id);
+int bch2_snapshot_set_equiv(struct btree_trans *trans, struct bkey_s_c k);
+
+/* only exported for tests: */
+int bch2_snapshot_node_create(struct btree_trans *, u32,
+			      u32 *, u32 *, unsigned);
+
+int bch2_check_snapshot_trees(struct bch_fs *);
+int bch2_check_snapshots(struct bch_fs *);
+
+int bch2_snapshot_node_set_deleted(struct btree_trans *, u32);
+int bch2_delete_dead_snapshots_hook(struct btree_trans *,
+				    struct btree_trans_commit_hook *);
+void bch2_delete_dead_snapshots_work(struct work_struct *);
+
+int bch2_snapshots_read(struct bch_fs *);
+void bch2_fs_snapshots_exit(struct bch_fs *);
+
+#endif /* _BCACHEFS_SNAPSHOT_H */

fs/bcachefs/subvolume.h

@@ -7,225 +7,8 @@
 
 enum bkey_invalid_flags;
 
-void bch2_snapshot_tree_to_text(struct printbuf *, struct bch_fs *, struct bkey_s_c);
-int bch2_snapshot_tree_invalid(const struct bch_fs *, struct bkey_s_c,
-			       enum bkey_invalid_flags, struct printbuf *);
-
-#define bch2_bkey_ops_snapshot_tree ((struct bkey_ops) {	\
-	.key_invalid	= bch2_snapshot_tree_invalid,		\
-	.val_to_text	= bch2_snapshot_tree_to_text,		\
-	.min_val_size	= 8,					\
-})
-
-int bch2_snapshot_tree_lookup(struct btree_trans *, u32, struct bch_snapshot_tree *);
-
-void bch2_snapshot_to_text(struct printbuf *, struct bch_fs *, struct bkey_s_c);
-int bch2_snapshot_invalid(const struct bch_fs *, struct bkey_s_c,
-			  enum bkey_invalid_flags, struct printbuf *);
-int bch2_mark_snapshot(struct btree_trans *, enum btree_id, unsigned,
-		       struct bkey_s_c, struct bkey_s_c, unsigned);
-
-#define bch2_bkey_ops_snapshot ((struct bkey_ops) {		\
-	.key_invalid	= bch2_snapshot_invalid,		\
-	.val_to_text	= bch2_snapshot_to_text,		\
-	.atomic_trigger	= bch2_mark_snapshot,			\
-	.min_val_size	= 24,					\
-})
-
-static inline struct snapshot_t *__snapshot_t(struct snapshot_table *t, u32 id)
-{
-	return &t->s[U32_MAX - id];
-}
-
-static inline const struct snapshot_t *snapshot_t(struct bch_fs *c, u32 id)
-{
-	return __snapshot_t(rcu_dereference(c->snapshots), id);
-}
-
-static inline u32 bch2_snapshot_tree(struct bch_fs *c, u32 id)
-{
-	rcu_read_lock();
-	id = snapshot_t(c, id)->tree;
-	rcu_read_unlock();
-
-	return id;
-}
-
-static inline u32 __bch2_snapshot_parent_early(struct bch_fs *c, u32 id)
-{
-	return snapshot_t(c, id)->parent;
-}
-
-static inline u32 bch2_snapshot_parent_early(struct bch_fs *c, u32 id)
-{
-	rcu_read_lock();
-	id = __bch2_snapshot_parent_early(c, id);
-	rcu_read_unlock();
-
-	return id;
-}
-
-static inline u32 __bch2_snapshot_parent(struct bch_fs *c, u32 id)
-{
-#ifdef CONFIG_BCACHEFS_DEBUG
-	u32 parent = snapshot_t(c, id)->parent;
-
-	if (parent &&
-	    snapshot_t(c, id)->depth != snapshot_t(c, parent)->depth + 1)
-		panic("id %u depth=%u parent %u depth=%u\n",
-		      id, snapshot_t(c, id)->depth,
-		      parent, snapshot_t(c, parent)->depth);
-
-	return parent;
-#else
-	return snapshot_t(c, id)->parent;
-#endif
-}
-
-static inline u32 bch2_snapshot_parent(struct bch_fs *c, u32 id)
-{
-	rcu_read_lock();
-	id = __bch2_snapshot_parent(c, id);
-	rcu_read_unlock();
-
-	return id;
-}
-
-static inline u32 bch2_snapshot_nth_parent(struct bch_fs *c, u32 id, u32 n)
-{
-	rcu_read_lock();
-	while (n--)
-		id = __bch2_snapshot_parent(c, id);
-	rcu_read_unlock();
-
-	return id;
-}
-
-static inline u32 bch2_snapshot_root(struct bch_fs *c, u32 id)
-{
-	u32 parent;
-
-	rcu_read_lock();
-	while ((parent = __bch2_snapshot_parent(c, id)))
-		id = parent;
-	rcu_read_unlock();
-
-	return id;
-}
-
-static inline u32 __bch2_snapshot_equiv(struct bch_fs *c, u32 id)
-{
-	return snapshot_t(c, id)->equiv;
-}
-
-static inline u32 bch2_snapshot_equiv(struct bch_fs *c, u32 id)
-{
-	rcu_read_lock();
-	id = __bch2_snapshot_equiv(c, id);
-	rcu_read_unlock();
-
-	return id;
-}
-
-static inline bool bch2_snapshot_is_equiv(struct bch_fs *c, u32 id)
-{
-	return id == bch2_snapshot_equiv(c, id);
-}
-
-static inline bool bch2_snapshot_is_internal_node(struct bch_fs *c, u32 id)
-{
-	const struct snapshot_t *s;
-	bool ret;
-
-	rcu_read_lock();
-	s = snapshot_t(c, id);
-	ret = s->children[0];
-	rcu_read_unlock();
-
-	return ret;
-}
-
-static inline u32 bch2_snapshot_is_leaf(struct bch_fs *c, u32 id)
-{
-	return !bch2_snapshot_is_internal_node(c, id);
-}
-
-static inline u32 bch2_snapshot_sibling(struct bch_fs *c, u32 id)
-{
-	const struct snapshot_t *s;
-	u32 parent = __bch2_snapshot_parent(c, id);
-
-	if (!parent)
-		return 0;
-
-	s = snapshot_t(c, __bch2_snapshot_parent(c, id));
-	if (id == s->children[0])
-		return s->children[1];
-	if (id == s->children[1])
-		return s->children[0];
-	return 0;
-}
-
-bool __bch2_snapshot_is_ancestor(struct bch_fs *, u32, u32);
-
-static inline bool bch2_snapshot_is_ancestor(struct bch_fs *c, u32 id, u32 ancestor)
-{
-	return id == ancestor
-		? true
-		: __bch2_snapshot_is_ancestor(c, id, ancestor);
-}
-
-static inline bool bch2_snapshot_has_children(struct bch_fs *c, u32 id)
-{
-	const struct snapshot_t *t;
-	bool ret;
-
-	rcu_read_lock();
-	t = snapshot_t(c, id);
-	ret = (t->children[0]|t->children[1]) != 0;
-	rcu_read_unlock();
-
-	return ret;
-}
-
-static inline bool snapshot_list_has_id(snapshot_id_list *s, u32 id)
-{
-	u32 *i;
-
-	darray_for_each(*s, i)
-		if (*i == id)
-			return true;
-	return false;
-}
-
-static inline bool snapshot_list_has_ancestor(struct bch_fs *c, snapshot_id_list *s, u32 id)
-{
-	u32 *i;
-
-	darray_for_each(*s, i)
-		if (bch2_snapshot_is_ancestor(c, id, *i))
-			return true;
-	return false;
-}
-
-static inline int snapshot_list_add(struct bch_fs *c, snapshot_id_list *s, u32 id)
-{
-	int ret;
-
-	BUG_ON(snapshot_list_has_id(s, id));
-	ret = darray_push(s, id);
-	if (ret)
-		bch_err(c, "error reallocating snapshot_id_list (size %zu)", s->size);
-	return ret;
-}
-
-int bch2_check_snapshot_trees(struct bch_fs *);
-int bch2_check_snapshots(struct bch_fs *);
 int bch2_check_subvols(struct bch_fs *);
 
-void bch2_fs_snapshots_exit(struct bch_fs *);
-int bch2_snapshots_read(struct bch_fs *);
-
 int bch2_subvolume_invalid(const struct bch_fs *, struct bkey_s_c,
 			   unsigned, struct printbuf *);
 void bch2_subvolume_to_text(struct printbuf *, struct bch_fs *, struct bkey_s_c);
@@ -238,14 +21,8 @@ void bch2_subvolume_to_text(struct printbuf *, struct bch_fs *, struct bkey_s_c)
 
 int bch2_subvolume_get(struct btree_trans *, unsigned,
 		       bool, int, struct bch_subvolume *);
-int bch2_snapshot_get_subvol(struct btree_trans *, u32,
-			     struct bch_subvolume *);
 int bch2_subvolume_get_snapshot(struct btree_trans *, u32, u32 *);
 
-/* only exported for tests: */
-int bch2_snapshot_node_create(struct btree_trans *, u32,
-			      u32 *, u32 *, unsigned);
-
 int bch2_delete_dead_snapshots(struct bch_fs *);
 void bch2_delete_dead_snapshots_async(struct bch_fs *);
 

fs/bcachefs/super.c

@@ -48,6 +48,7 @@
 #include "recovery.h"
 #include "replicas.h"
 #include "sb-clean.h"
+#include "snapshot.h"
 #include "subvolume.h"
 #include "super.h"
 #include "super-io.h"

fs/bcachefs/tests.c

@@ -4,7 +4,7 @@
 #include "bcachefs.h"
 #include "btree_update.h"
 #include "journal_reclaim.h"
-#include "subvolume.h"
+#include "snapshot.h"
 #include "tests.h"
 
 #include "linux/kthread.h"

fs/bcachefs/util.h

@@ -842,6 +842,11 @@ static inline int u8_cmp(u8 l, u8 r)
 	return cmp_int(l, r);
 }
 
+static inline int cmp_le32(__le32 l, __le32 r)
+{
+	return cmp_int(le32_to_cpu(l), le32_to_cpu(r));
+}
+
 #include <linux/uuid.h>
 
 #endif /* _BCACHEFS_UTIL_H */