fs/bcachefs/btree_update.h - linux - Git at Google

 /* SPDX-License-Identifier: GPL-2.0 */
 #ifndef _BCACHEFS_BTREE_UPDATE_H
 #define _BCACHEFS_BTREE_UPDATE_H

 #include "btree_iter.h"
 #include "journal.h"

 struct bch_fs;
 struct btree;

 void bch2_btree_node_prep_for_write(struct btree_trans *,
 				    struct btree_path *, struct btree *);
 bool bch2_btree_bset_insert_key(struct btree_trans *, struct btree_path *,
 				struct btree *, struct btree_node_iter *,
 				struct bkey_i *);

 int bch2_btree_node_flush0(struct journal *, struct journal_entry_pin *, u64);
 int bch2_btree_node_flush1(struct journal *, struct journal_entry_pin *, u64);
 void bch2_btree_add_journal_pin(struct bch_fs *, struct btree *, u64);

 void bch2_btree_insert_key_leaf(struct btree_trans *, struct btree_path *,
 				struct bkey_i *, u64);

 #define BCH_TRANS_COMMIT_FLAGS()							\
 	x(no_enospc,	"don't check for enospc")					\
 	x(no_check_rw,	"don't attempt to take a ref on c->writes")			\
 	x(lazy_rw,	"go read-write if we haven't yet - only for use in recovery")	\
 	x(no_journal_res, "don't take a journal reservation, instead "			\
 			"pin journal entry referred to by trans->journal_res.seq")	\
 	x(journal_reclaim, "operation required for journal reclaim; may return error"	\
 			"instead of deadlocking if BCH_WATERMARK_reclaim not specified")\
 	x(skip_accounting_apply, "we're in journal replay - accounting updates have already been applied")

 enum __bch_trans_commit_flags {
 	/* First bits for bch_watermark: */
 	__BCH_TRANS_COMMIT_FLAGS_START = BCH_WATERMARK_BITS,
 #define x(n, ...)	__BCH_TRANS_COMMIT_##n,
 	BCH_TRANS_COMMIT_FLAGS()
 #undef x
 };

 enum bch_trans_commit_flags {
 #define x(n, ...)	BCH_TRANS_COMMIT_##n = BIT(__BCH_TRANS_COMMIT_##n),
 	BCH_TRANS_COMMIT_FLAGS()
 #undef x
 };

 void bch2_trans_commit_flags_to_text(struct printbuf *, enum bch_trans_commit_flags);

 int bch2_btree_delete_extent_at(struct btree_trans *, struct btree_iter *,
 				unsigned, unsigned);
 int bch2_btree_delete_at(struct btree_trans *, struct btree_iter *, unsigned);
 int bch2_btree_delete(struct btree_trans *, enum btree_id, struct bpos, unsigned);

 int bch2_btree_insert_nonextent(struct btree_trans *, enum btree_id,
 				struct bkey_i *, enum btree_iter_update_trigger_flags);

 int bch2_btree_insert_trans(struct btree_trans *, enum btree_id, struct bkey_i *,
 			enum btree_iter_update_trigger_flags);
 int bch2_btree_insert(struct bch_fs *, enum btree_id, struct bkey_i *, struct
 		disk_reservation *, int flags, enum
 		btree_iter_update_trigger_flags iter_flags);

 int bch2_btree_delete_range_trans(struct btree_trans *, enum btree_id,
 				  struct bpos, struct bpos, unsigned, u64 *);
 int bch2_btree_delete_range(struct bch_fs *, enum btree_id,
 			    struct bpos, struct bpos, unsigned, u64 *);

 int bch2_btree_bit_mod(struct btree_trans *, enum btree_id, struct bpos, bool);
 int bch2_btree_bit_mod_buffered(struct btree_trans *, enum btree_id, struct bpos, bool);

 static inline int bch2_btree_delete_at_buffered(struct btree_trans *trans,
 						enum btree_id btree, struct bpos pos)
 {
 	return bch2_btree_bit_mod_buffered(trans, btree, pos, false);
 }

 int __bch2_insert_snapshot_whiteouts(struct btree_trans *, enum btree_id,
 				     struct bpos, struct bpos);

 /*
  * For use when splitting extents in existing snapshots:
  *
  * If @old_pos is an interior snapshot node, iterate over descendent snapshot
  * nodes: for every descendent snapshot in whiche @old_pos is overwritten and
  * not visible, emit a whiteout at @new_pos.
  */
 static inline int bch2_insert_snapshot_whiteouts(struct btree_trans *trans,
 						 enum btree_id btree,
 						 struct bpos old_pos,
 						 struct bpos new_pos)
 {
 	if (!btree_type_has_snapshots(btree) ||
 	    bkey_eq(old_pos, new_pos))
 		return 0;

 	return __bch2_insert_snapshot_whiteouts(trans, btree, old_pos, new_pos);
 }

 int bch2_trans_update_extent_overwrite(struct btree_trans *, struct btree_iter *,
 				       enum btree_iter_update_trigger_flags,
 				       struct bkey_s_c, struct bkey_s_c);

 int bch2_bkey_get_empty_slot(struct btree_trans *, struct btree_iter *,
 			     enum btree_id, struct bpos);

 int __must_check bch2_trans_update(struct btree_trans *, struct btree_iter *,
 				   struct bkey_i *, enum btree_iter_update_trigger_flags);

 struct jset_entry *__bch2_trans_jset_entry_alloc(struct btree_trans *, unsigned);

 static inline struct jset_entry *btree_trans_journal_entries_top(struct btree_trans *trans)
 {
 	return (void *) ((u64 *) trans->journal_entries + trans->journal_entries_u64s);
 }

 static inline struct jset_entry *
 bch2_trans_jset_entry_alloc(struct btree_trans *trans, unsigned u64s)
 {
 	if (!trans->journal_entries ||
 	    trans->journal_entries_u64s + u64s > trans->journal_entries_size)
 		return __bch2_trans_jset_entry_alloc(trans, u64s);

 	struct jset_entry *e = btree_trans_journal_entries_top(trans);
 	trans->journal_entries_u64s += u64s;
 	return e;
 }

 int bch2_btree_insert_clone_trans(struct btree_trans *, enum btree_id, struct bkey_i *);

 static inline int __must_check bch2_trans_update_buffered(struct btree_trans *trans,
 					    enum btree_id btree,
 					    struct bkey_i *k)
 {
 	/*
 	 * Most updates skip the btree write buffer until journal replay is
 	 * finished because synchronization with journal replay relies on having
 	 * a btree node locked - if we're overwriting a key in the journal that
 	 * journal replay hasn't yet replayed, we have to mark it as
 	 * overwritten.
 	 *
 	 * But accounting updates don't overwrite, they're deltas, and they have
 	 * to be flushed to the btree strictly in order for journal replay to be
 	 * able to tell which updates need to be applied:
 	 */
 	if (k->k.type != KEY_TYPE_accounting &&
 	    unlikely(trans->journal_replay_not_finished))
 		return bch2_btree_insert_clone_trans(trans, btree, k);

 	struct jset_entry *e = bch2_trans_jset_entry_alloc(trans, jset_u64s(k->k.u64s));
 	int ret = PTR_ERR_OR_ZERO(e);
 	if (ret)
 		return ret;

 	journal_entry_init(e, BCH_JSET_ENTRY_write_buffer_keys, btree, 0, k->k.u64s);
 	bkey_copy(e->start, k);
 	return 0;
 }

 void bch2_trans_commit_hook(struct btree_trans *,
 			    struct btree_trans_commit_hook *);
 int __bch2_trans_commit(struct btree_trans *, unsigned);

 __printf(2, 3) int bch2_fs_log_msg(struct bch_fs *, const char *, ...);
 __printf(2, 3) int bch2_journal_log_msg(struct bch_fs *, const char *, ...);

 /**
  * bch2_trans_commit - insert keys at given iterator positions
  *
  * This is main entry point for btree updates.
  *
  * Return values:
  * -EROFS: filesystem read only
  * -EIO: journal or btree node IO error
  */
 static inline int bch2_trans_commit(struct btree_trans *trans,
 				    struct disk_reservation *disk_res,
 				    u64 *journal_seq,
 				    unsigned flags)
 {
 	trans->disk_res		= disk_res;
 	trans->journal_seq	= journal_seq;

 	return __bch2_trans_commit(trans, flags);
 }

 #define commit_do(_trans, _disk_res, _journal_seq, _flags, _do)	\
 	lockrestart_do(_trans, _do ?: bch2_trans_commit(_trans, (_disk_res),\
 					(_journal_seq), (_flags)))

 #define nested_commit_do(_trans, _disk_res, _journal_seq, _flags, _do)	\
 	nested_lockrestart_do(_trans, _do ?: bch2_trans_commit(_trans, (_disk_res),\
 					(_journal_seq), (_flags)))

 #define bch2_trans_commit_do(_c, _disk_res, _journal_seq, _flags, _do)		\
 	bch2_trans_run(_c, commit_do(trans, _disk_res, _journal_seq, _flags, _do))

 #define trans_for_each_update(_trans, _i)				\
 	for (struct btree_insert_entry *_i = (_trans)->updates;		\
 	     (_i) < (_trans)->updates + (_trans)->nr_updates;		\
 	     (_i)++)

 static inline void bch2_trans_reset_updates(struct btree_trans *trans)
 {
 	trans_for_each_update(trans, i)
 		bch2_path_put(trans, i->path, true);

 	trans->nr_updates		= 0;
 	trans->journal_entries_u64s	= 0;
 	trans->hooks			= NULL;
 	trans->extra_disk_res		= 0;
 }

 static inline struct bkey_i *__bch2_bkey_make_mut_noupdate(struct btree_trans *trans, struct bkey_s_c k,
 						  unsigned type, unsigned min_bytes)
 {
 	unsigned bytes = max_t(unsigned, min_bytes, bkey_bytes(k.k));
 	struct bkey_i *mut;

 	if (type && k.k->type != type)
 		return ERR_PTR(-ENOENT);

 	/* extra padding for varint_decode_fast... */
 	mut = bch2_trans_kmalloc_nomemzero(trans, bytes + 8);
 	if (!IS_ERR(mut)) {
 		bkey_reassemble(mut, k);

 		if (unlikely(bytes > bkey_bytes(k.k))) {
 			memset((void *) mut + bkey_bytes(k.k), 0,
 			       bytes - bkey_bytes(k.k));
 			mut->k.u64s = DIV_ROUND_UP(bytes, sizeof(u64));
 		}
 	}
 	return mut;
 }

 static inline struct bkey_i *bch2_bkey_make_mut_noupdate(struct btree_trans *trans, struct bkey_s_c k)
 {
 	return __bch2_bkey_make_mut_noupdate(trans, k, 0, 0);
 }

 #define bch2_bkey_make_mut_noupdate_typed(_trans, _k, _type)		\
 	bkey_i_to_##_type(__bch2_bkey_make_mut_noupdate(_trans, _k,	\
 				KEY_TYPE_##_type, sizeof(struct bkey_i_##_type)))

 static inline struct bkey_i *__bch2_bkey_make_mut(struct btree_trans *trans, struct btree_iter *iter,
 					struct bkey_s_c *k, unsigned flags,
 					unsigned type, unsigned min_bytes)
 {
 	struct bkey_i *mut = __bch2_bkey_make_mut_noupdate(trans, *k, type, min_bytes);
 	int ret;

 	if (IS_ERR(mut))
 		return mut;

 	ret = bch2_trans_update(trans, iter, mut, flags);
 	if (ret)
 		return ERR_PTR(ret);

 	*k = bkey_i_to_s_c(mut);
 	return mut;
 }

 static inline struct bkey_i *bch2_bkey_make_mut(struct btree_trans *trans, struct btree_iter *iter,
 						struct bkey_s_c *k, unsigned flags)
 {
 	return __bch2_bkey_make_mut(trans, iter, k, flags, 0, 0);
 }

 #define bch2_bkey_make_mut_typed(_trans, _iter, _k, _flags, _type)	\
 	bkey_i_to_##_type(__bch2_bkey_make_mut(_trans, _iter, _k, _flags,\
 				KEY_TYPE_##_type, sizeof(struct bkey_i_##_type)))

 static inline struct bkey_i *__bch2_bkey_get_mut_noupdate(struct btree_trans *trans,
 					 struct btree_iter *iter,
 					 unsigned btree_id, struct bpos pos,
 					 unsigned flags, unsigned type, unsigned min_bytes)
 {
 	struct bkey_s_c k = __bch2_bkey_get_iter(trans, iter,
 				btree_id, pos, flags|BTREE_ITER_intent, type);
 	struct bkey_i *ret = IS_ERR(k.k)
 		? ERR_CAST(k.k)
 		: __bch2_bkey_make_mut_noupdate(trans, k, 0, min_bytes);
 	if (IS_ERR(ret))
 		bch2_trans_iter_exit(trans, iter);
 	return ret;
 }

 static inline struct bkey_i *bch2_bkey_get_mut_noupdate(struct btree_trans *trans,
 					       struct btree_iter *iter,
 					       unsigned btree_id, struct bpos pos,
 					       unsigned flags)
 {
 	return __bch2_bkey_get_mut_noupdate(trans, iter, btree_id, pos, flags, 0, 0);
 }

 static inline struct bkey_i *__bch2_bkey_get_mut(struct btree_trans *trans,
 					 struct btree_iter *iter,
 					 unsigned btree_id, struct bpos pos,
 					 unsigned flags, unsigned type, unsigned min_bytes)
 {
 	struct bkey_i *mut = __bch2_bkey_get_mut_noupdate(trans, iter,
 				btree_id, pos, flags|BTREE_ITER_intent, type, min_bytes);
 	int ret;

 	if (IS_ERR(mut))
 		return mut;

 	ret = bch2_trans_update(trans, iter, mut, flags);
 	if (ret) {
 		bch2_trans_iter_exit(trans, iter);
 		return ERR_PTR(ret);
 	}

 	return mut;
 }

 static inline struct bkey_i *bch2_bkey_get_mut_minsize(struct btree_trans *trans,
 						       struct btree_iter *iter,
 						       unsigned btree_id, struct bpos pos,
 						       unsigned flags, unsigned min_bytes)
 {
 	return __bch2_bkey_get_mut(trans, iter, btree_id, pos, flags, 0, min_bytes);
 }

 static inline struct bkey_i *bch2_bkey_get_mut(struct btree_trans *trans,
 					       struct btree_iter *iter,
 					       unsigned btree_id, struct bpos pos,
 					       unsigned flags)
 {
 	return __bch2_bkey_get_mut(trans, iter, btree_id, pos, flags, 0, 0);
 }

 #define bch2_bkey_get_mut_typed(_trans, _iter, _btree_id, _pos, _flags, _type)\
 	bkey_i_to_##_type(__bch2_bkey_get_mut(_trans, _iter,		\
 			_btree_id, _pos, _flags,			\
 			KEY_TYPE_##_type, sizeof(struct bkey_i_##_type)))

 static inline struct bkey_i *__bch2_bkey_alloc(struct btree_trans *trans, struct btree_iter *iter,
 					       unsigned flags, unsigned type, unsigned val_size)
 {
 	struct bkey_i *k = bch2_trans_kmalloc(trans, sizeof(*k) + val_size);
 	int ret;

 	if (IS_ERR(k))
 		return k;

 	bkey_init(&k->k);
 	k->k.p = iter->pos;
 	k->k.type = type;
 	set_bkey_val_bytes(&k->k, val_size);

 	ret = bch2_trans_update(trans, iter, k, flags);
 	if (unlikely(ret))
 		return ERR_PTR(ret);
 	return k;
 }

 #define bch2_bkey_alloc(_trans, _iter, _flags, _type)			\
 	bkey_i_to_##_type(__bch2_bkey_alloc(_trans, _iter, _flags,	\
 				KEY_TYPE_##_type, sizeof(struct bch_##_type)))

 #endif /* _BCACHEFS_BTREE_UPDATE_H */
	/* SPDX-License-Identifier: GPL-2.0 */
	#ifndef _BCACHEFS_BTREE_UPDATE_H
	#define _BCACHEFS_BTREE_UPDATE_H

	#include "btree_iter.h"
	#include "journal.h"

	struct bch_fs;
	struct btree;

	void bch2_btree_node_prep_for_write(struct btree_trans *,
	struct btree_path , struct btree );
	bool bch2_btree_bset_insert_key(struct btree_trans , struct btree_path ,
	struct btree , struct btree_node_iter ,
	struct bkey_i *);

	int bch2_btree_node_flush0(struct journal , struct journal_entry_pin , u64);
	int bch2_btree_node_flush1(struct journal , struct journal_entry_pin , u64);
	void bch2_btree_add_journal_pin(struct bch_fs , struct btree , u64);

	void bch2_btree_insert_key_leaf(struct btree_trans , struct btree_path ,
	struct bkey_i *, u64);

	#define BCH_TRANS_COMMIT_FLAGS() \
	x(no_enospc, "don't check for enospc") \
	x(no_check_rw, "don't attempt to take a ref on c->writes") \
	x(lazy_rw, "go read-write if we haven't yet - only for use in recovery") \
	x(no_journal_res, "don't take a journal reservation, instead " \
	"pin journal entry referred to by trans->journal_res.seq") \
	x(journal_reclaim, "operation required for journal reclaim; may return error" \
	"instead of deadlocking if BCH_WATERMARK_reclaim not specified")\
	x(skip_accounting_apply, "we're in journal replay - accounting updates have already been applied")

	enum __bch_trans_commit_flags {
	/* First bits for bch_watermark: */
	__BCH_TRANS_COMMIT_FLAGS_START = BCH_WATERMARK_BITS,
	#define x(n, ...) __BCH_TRANS_COMMIT_##n,
	BCH_TRANS_COMMIT_FLAGS()
	#undef x
	};

	enum bch_trans_commit_flags {
	#define x(n, ...) BCH_TRANS_COMMIT_##n = BIT(__BCH_TRANS_COMMIT_##n),
	BCH_TRANS_COMMIT_FLAGS()
	#undef x
	};

	void bch2_trans_commit_flags_to_text(struct printbuf *, enum bch_trans_commit_flags);

	int bch2_btree_delete_extent_at(struct btree_trans , struct btree_iter ,
	unsigned, unsigned);
	int bch2_btree_delete_at(struct btree_trans , struct btree_iter , unsigned);
	int bch2_btree_delete(struct btree_trans *, enum btree_id, struct bpos, unsigned);

	int bch2_btree_insert_nonextent(struct btree_trans *, enum btree_id,
	struct bkey_i *, enum btree_iter_update_trigger_flags);

	int bch2_btree_insert_trans(struct btree_trans , enum btree_id, struct bkey_i ,
	enum btree_iter_update_trigger_flags);
	int bch2_btree_insert(struct bch_fs , enum btree_id, struct bkey_i , struct
	disk_reservation *, int flags, enum
	btree_iter_update_trigger_flags iter_flags);

	int bch2_btree_delete_range_trans(struct btree_trans *, enum btree_id,
	struct bpos, struct bpos, unsigned, u64 *);
	int bch2_btree_delete_range(struct bch_fs *, enum btree_id,
	struct bpos, struct bpos, unsigned, u64 *);

	int bch2_btree_bit_mod(struct btree_trans *, enum btree_id, struct bpos, bool);
	int bch2_btree_bit_mod_buffered(struct btree_trans *, enum btree_id, struct bpos, bool);

	static inline int bch2_btree_delete_at_buffered(struct btree_trans *trans,
	enum btree_id btree, struct bpos pos)
	{
	return bch2_btree_bit_mod_buffered(trans, btree, pos, false);
	}

	int __bch2_insert_snapshot_whiteouts(struct btree_trans *, enum btree_id,
	struct bpos, struct bpos);

	/*
	* For use when splitting extents in existing snapshots:
	*
	* If @old_pos is an interior snapshot node, iterate over descendent snapshot
	* nodes: for every descendent snapshot in whiche @old_pos is overwritten and
	* not visible, emit a whiteout at @new_pos.
	*/
	static inline int bch2_insert_snapshot_whiteouts(struct btree_trans *trans,
	enum btree_id btree,
	struct bpos old_pos,
	struct bpos new_pos)
	{
	if (!btree_type_has_snapshots(btree) \|\|
	bkey_eq(old_pos, new_pos))
	return 0;

	return __bch2_insert_snapshot_whiteouts(trans, btree, old_pos, new_pos);
	}

	int bch2_trans_update_extent_overwrite(struct btree_trans , struct btree_iter ,
	enum btree_iter_update_trigger_flags,
	struct bkey_s_c, struct bkey_s_c);

	int bch2_bkey_get_empty_slot(struct btree_trans , struct btree_iter ,
	enum btree_id, struct bpos);

	int __must_check bch2_trans_update(struct btree_trans , struct btree_iter ,
	struct bkey_i *, enum btree_iter_update_trigger_flags);

	struct jset_entry __bch2_trans_jset_entry_alloc(struct btree_trans , unsigned);

	static inline struct jset_entry btree_trans_journal_entries_top(struct btree_trans trans)
	{
	return (void ) ((u64 ) trans->journal_entries + trans->journal_entries_u64s);
	}

	static inline struct jset_entry *
	bch2_trans_jset_entry_alloc(struct btree_trans *trans, unsigned u64s)
	{
	if (!trans->journal_entries \|\|
	trans->journal_entries_u64s + u64s > trans->journal_entries_size)
	return __bch2_trans_jset_entry_alloc(trans, u64s);

	struct jset_entry *e = btree_trans_journal_entries_top(trans);
	trans->journal_entries_u64s += u64s;
	return e;
	}

	int bch2_btree_insert_clone_trans(struct btree_trans , enum btree_id, struct bkey_i );

	static inline int __must_check bch2_trans_update_buffered(struct btree_trans *trans,
	enum btree_id btree,
	struct bkey_i *k)
	{
	/*
	* Most updates skip the btree write buffer until journal replay is
	* finished because synchronization with journal replay relies on having
	* a btree node locked - if we're overwriting a key in the journal that
	* journal replay hasn't yet replayed, we have to mark it as
	* overwritten.
	*
	* But accounting updates don't overwrite, they're deltas, and they have
	* to be flushed to the btree strictly in order for journal replay to be
	* able to tell which updates need to be applied:
	*/
	if (k->k.type != KEY_TYPE_accounting &&
	unlikely(trans->journal_replay_not_finished))
	return bch2_btree_insert_clone_trans(trans, btree, k);

	struct jset_entry *e = bch2_trans_jset_entry_alloc(trans, jset_u64s(k->k.u64s));
	int ret = PTR_ERR_OR_ZERO(e);
	if (ret)
	return ret;

	journal_entry_init(e, BCH_JSET_ENTRY_write_buffer_keys, btree, 0, k->k.u64s);
	bkey_copy(e->start, k);
	return 0;
	}

	void bch2_trans_commit_hook(struct btree_trans *,
	struct btree_trans_commit_hook *);
	int __bch2_trans_commit(struct btree_trans *, unsigned);

	__printf(2, 3) int bch2_fs_log_msg(struct bch_fs , const char , ...);
	__printf(2, 3) int bch2_journal_log_msg(struct bch_fs , const char , ...);

	/**
	* bch2_trans_commit - insert keys at given iterator positions
	*
	* This is main entry point for btree updates.
	*
	* Return values:
	* -EROFS: filesystem read only
	* -EIO: journal or btree node IO error
	*/
	static inline int bch2_trans_commit(struct btree_trans *trans,
	struct disk_reservation *disk_res,
	u64 *journal_seq,
	unsigned flags)
	{
	trans->disk_res = disk_res;
	trans->journal_seq = journal_seq;

	return __bch2_trans_commit(trans, flags);
	}

	#define commit_do(_trans, _disk_res, _journal_seq, _flags, _do) \
	lockrestart_do(_trans, _do ?: bch2_trans_commit(_trans, (_disk_res),\
	(_journal_seq), (_flags)))

	#define nested_commit_do(_trans, _disk_res, _journal_seq, _flags, _do) \
	nested_lockrestart_do(_trans, _do ?: bch2_trans_commit(_trans, (_disk_res),\
	(_journal_seq), (_flags)))

	#define bch2_trans_commit_do(_c, _disk_res, _journal_seq, _flags, _do) \
	bch2_trans_run(_c, commit_do(trans, _disk_res, _journal_seq, _flags, _do))

	#define trans_for_each_update(_trans, _i) \
	for (struct btree_insert_entry *_i = (_trans)->updates; \
	(_i) < (_trans)->updates + (_trans)->nr_updates; \
	(_i)++)

	static inline void bch2_trans_reset_updates(struct btree_trans *trans)
	{
	trans_for_each_update(trans, i)
	bch2_path_put(trans, i->path, true);

	trans->nr_updates = 0;
	trans->journal_entries_u64s = 0;
	trans->hooks = NULL;
	trans->extra_disk_res = 0;
	}

	static inline struct bkey_i __bch2_bkey_make_mut_noupdate(struct btree_trans trans, struct bkey_s_c k,
	unsigned type, unsigned min_bytes)
	{
	unsigned bytes = max_t(unsigned, min_bytes, bkey_bytes(k.k));
	struct bkey_i *mut;

	if (type && k.k->type != type)
	return ERR_PTR(-ENOENT);

	/* extra padding for varint_decode_fast... */
	mut = bch2_trans_kmalloc_nomemzero(trans, bytes + 8);
	if (!IS_ERR(mut)) {
	bkey_reassemble(mut, k);

	if (unlikely(bytes > bkey_bytes(k.k))) {
	memset((void *) mut + bkey_bytes(k.k), 0,
	bytes - bkey_bytes(k.k));
	mut->k.u64s = DIV_ROUND_UP(bytes, sizeof(u64));
	}
	}
	return mut;
	}

	static inline struct bkey_i bch2_bkey_make_mut_noupdate(struct btree_trans trans, struct bkey_s_c k)
	{
	return __bch2_bkey_make_mut_noupdate(trans, k, 0, 0);
	}

	#define bch2_bkey_make_mut_noupdate_typed(_trans, _k, _type) \
	bkey_i_to_##_type(__bch2_bkey_make_mut_noupdate(_trans, _k, \
	KEY_TYPE_##_type, sizeof(struct bkey_i_##_type)))

	static inline struct bkey_i __bch2_bkey_make_mut(struct btree_trans trans, struct btree_iter *iter,
	struct bkey_s_c *k, unsigned flags,
	unsigned type, unsigned min_bytes)
	{
	struct bkey_i mut = __bch2_bkey_make_mut_noupdate(trans, k, type, min_bytes);
	int ret;

	if (IS_ERR(mut))
	return mut;

	ret = bch2_trans_update(trans, iter, mut, flags);
	if (ret)
	return ERR_PTR(ret);

	*k = bkey_i_to_s_c(mut);
	return mut;
	}

	static inline struct bkey_i bch2_bkey_make_mut(struct btree_trans trans, struct btree_iter *iter,
	struct bkey_s_c *k, unsigned flags)
	{
	return __bch2_bkey_make_mut(trans, iter, k, flags, 0, 0);
	}

	#define bch2_bkey_make_mut_typed(_trans, _iter, _k, _flags, _type) \
	bkey_i_to_##_type(__bch2_bkey_make_mut(_trans, _iter, _k, _flags,\
	KEY_TYPE_##_type, sizeof(struct bkey_i_##_type)))

	static inline struct bkey_i __bch2_bkey_get_mut_noupdate(struct btree_trans trans,
	struct btree_iter *iter,
	unsigned btree_id, struct bpos pos,
	unsigned flags, unsigned type, unsigned min_bytes)
	{
	struct bkey_s_c k = __bch2_bkey_get_iter(trans, iter,
	btree_id, pos, flags\|BTREE_ITER_intent, type);
	struct bkey_i *ret = IS_ERR(k.k)
	? ERR_CAST(k.k)
	: __bch2_bkey_make_mut_noupdate(trans, k, 0, min_bytes);
	if (IS_ERR(ret))
	bch2_trans_iter_exit(trans, iter);
	return ret;
	}

	static inline struct bkey_i bch2_bkey_get_mut_noupdate(struct btree_trans trans,
	struct btree_iter *iter,
	unsigned btree_id, struct bpos pos,
	unsigned flags)
	{
	return __bch2_bkey_get_mut_noupdate(trans, iter, btree_id, pos, flags, 0, 0);
	}

	static inline struct bkey_i __bch2_bkey_get_mut(struct btree_trans trans,
	struct btree_iter *iter,
	unsigned btree_id, struct bpos pos,
	unsigned flags, unsigned type, unsigned min_bytes)
	{
	struct bkey_i *mut = __bch2_bkey_get_mut_noupdate(trans, iter,
	btree_id, pos, flags\|BTREE_ITER_intent, type, min_bytes);
	int ret;

	if (IS_ERR(mut))
	return mut;

	ret = bch2_trans_update(trans, iter, mut, flags);
	if (ret) {
	bch2_trans_iter_exit(trans, iter);
	return ERR_PTR(ret);
	}

	return mut;
	}

	static inline struct bkey_i bch2_bkey_get_mut_minsize(struct btree_trans trans,
	struct btree_iter *iter,
	unsigned btree_id, struct bpos pos,
	unsigned flags, unsigned min_bytes)
	{
	return __bch2_bkey_get_mut(trans, iter, btree_id, pos, flags, 0, min_bytes);
	}

	static inline struct bkey_i bch2_bkey_get_mut(struct btree_trans trans,
	struct btree_iter *iter,
	unsigned btree_id, struct bpos pos,
	unsigned flags)
	{
	return __bch2_bkey_get_mut(trans, iter, btree_id, pos, flags, 0, 0);
	}

	#define bch2_bkey_get_mut_typed(_trans, _iter, _btree_id, _pos, _flags, _type)\
	bkey_i_to_##_type(__bch2_bkey_get_mut(_trans, _iter, \
	_btree_id, _pos, _flags, \
	KEY_TYPE_##_type, sizeof(struct bkey_i_##_type)))

	static inline struct bkey_i __bch2_bkey_alloc(struct btree_trans trans, struct btree_iter *iter,
	unsigned flags, unsigned type, unsigned val_size)
	{
	struct bkey_i k = bch2_trans_kmalloc(trans, sizeof(k) + val_size);
	int ret;

	if (IS_ERR(k))
	return k;

	bkey_init(&k->k);
	k->k.p = iter->pos;
	k->k.type = type;
	set_bkey_val_bytes(&k->k, val_size);

	ret = bch2_trans_update(trans, iter, k, flags);
	if (unlikely(ret))
	return ERR_PTR(ret);
	return k;
	}

	#define bch2_bkey_alloc(_trans, _iter, _flags, _type) \
	bkey_i_to_##_type(__bch2_bkey_alloc(_trans, _iter, _flags, \
	KEY_TYPE_##_type, sizeof(struct bch_##_type)))

	#endif /* _BCACHEFS_BTREE_UPDATE_H */