Commit 85d8cf16 authored by Kent Overstreet's avatar Kent Overstreet Committed by Kent Overstreet
Browse files

bcachefs: bch2_btree_iter_peek_upto() 



In BTREE_ITER_FILTER_SNAPHOTS mode, we skip over keys in unrelated
snapshots. When we hit the end of an inode, if the next inode(s) are in
a different subvolume, we could potentially have to skip past many keys
before finding a key we can return to the caller, so they can terminate
the iteration.

This adds a peek_upto() variant to solve this problem, to be used when
we know the range we're searching within.

Signed-off-by: default avatarKent Overstreet <kent.overstreet@gmail.com>
parent d4d24a65

fs/bcachefs/btree_iter.c

+26 −10
Original line number Diff line number Diff line
@@ -2346,11 +2346,12 @@ static struct bkey_s_c __bch2_btree_iter_peek(struct btree_iter *iter, struct bp 
 * bch2_btree_iter_peek: returns first key greater than or equal to iterator's

 * current position

 */

struct bkey_s_c bch2_btree_iter_peek(struct btree_iter *iter)

struct bkey_s_c bch2_btree_iter_peek_upto(struct btree_iter *iter, struct bpos end)

{

	struct btree_trans *trans = iter->trans;

	struct bpos search_key = btree_iter_search_key(iter);

	struct bkey_s_c k;

	struct bpos iter_pos;

	int ret;



	if (iter->update_path) {
@@ -2366,6 +2367,24 @@ struct bkey_s_c bch2_btree_iter_peek(struct btree_iter *iter) 
		if (!k.k || bkey_err(k))

			goto out;



		/*

		 * iter->pos should be mononotically increasing, and always be

		 * equal to the key we just returned - except extents can

		 * straddle iter->pos:

		 */

		if (!(iter->flags & BTREE_ITER_IS_EXTENTS))

			iter_pos = k.k->p;

		else if (bkey_cmp(bkey_start_pos(k.k), iter->pos) > 0)

			iter_pos = bkey_start_pos(k.k);

		else

			iter_pos = iter->pos;



		if (bkey_cmp(iter_pos, end) > 0) {

			bch2_btree_iter_set_pos(iter, end);

			k = bkey_s_c_null;

			goto out;

		}



		if (iter->update_path &&

		    bkey_cmp(iter->update_path->pos, k.k->p)) {

			bch2_path_put(trans, iter->update_path,
@@ -2419,14 +2438,7 @@ struct bkey_s_c bch2_btree_iter_peek(struct btree_iter *iter) 
		break;

	}



	/*

	 * iter->pos should be mononotically increasing, and always be equal to

	 * the key we just returned - except extents can straddle iter->pos:

	 */

	if (!(iter->flags & BTREE_ITER_IS_EXTENTS))

		iter->pos = k.k->p;

	else if (bkey_cmp(bkey_start_pos(k.k), iter->pos) > 0)

		iter->pos = bkey_start_pos(k.k);

	iter->pos = iter_pos;



	iter->path = bch2_btree_path_set_pos(trans, iter->path, k.k->p,

				iter->flags & BTREE_ITER_INTENT);
@@ -2658,9 +2670,13 @@ struct bkey_s_c bch2_btree_iter_peek_slot(struct btree_iter *iter) 


		if (iter->flags & BTREE_ITER_INTENT) {

			struct btree_iter iter2;

			struct bpos end = iter->pos;



			if (iter->flags & BTREE_ITER_IS_EXTENTS)

				end.offset = U64_MAX;



			bch2_trans_copy_iter(&iter2, iter);

			k = bch2_btree_iter_peek(&iter2);

			k = bch2_btree_iter_peek_upto(&iter2, end);



			if (k.k && !bkey_err(k)) {

				iter->k = iter2.k;

fs/bcachefs/btree_iter.h

+28 −2
Original line number Diff line number Diff line
@@ -245,9 +245,14 @@ int __must_check bch2_btree_iter_traverse(struct btree_iter *); 
struct btree *bch2_btree_iter_peek_node(struct btree_iter *);

struct btree *bch2_btree_iter_next_node(struct btree_iter *);



struct bkey_s_c bch2_btree_iter_peek(struct btree_iter *);

struct bkey_s_c bch2_btree_iter_peek_upto(struct btree_iter *, struct bpos);

struct bkey_s_c bch2_btree_iter_next(struct btree_iter *);



static inline struct bkey_s_c bch2_btree_iter_peek(struct btree_iter *iter)

{

	return bch2_btree_iter_peek_upto(iter, SPOS_MAX);

}



struct bkey_s_c bch2_btree_iter_peek_prev(struct btree_iter *);

struct bkey_s_c bch2_btree_iter_prev(struct btree_iter *);
@@ -349,6 +354,19 @@ static inline struct bkey_s_c bch2_btree_iter_peek_type(struct btree_iter *iter, 
		: bch2_btree_iter_peek(iter);

}



static inline struct bkey_s_c bch2_btree_iter_peek_upto_type(struct btree_iter *iter,

							     struct bpos end,

							     unsigned flags)

{

	if (!(flags & BTREE_ITER_SLOTS))

		return bch2_btree_iter_peek_upto(iter, end);



	if (bkey_cmp(iter->pos, end) > 0)

		return bkey_s_c_null;



	return bch2_btree_iter_peek_slot(iter);

}



static inline int btree_trans_too_many_iters(struct btree_trans *trans)

{

	return hweight64(trans->paths_allocated) > BTREE_ITER_MAX / 2
@@ -385,6 +403,14 @@ __bch2_btree_iter_peek_and_restart(struct btree_trans *trans, 
	     !((_ret) = bkey_err(_k)) && (_k).k;			\

	     bch2_btree_iter_advance(&(_iter)))



#define for_each_btree_key_upto_norestart(_trans, _iter, _btree_id,	\

			   _start, _end, _flags, _k, _ret)		\

	for (bch2_trans_iter_init((_trans), &(_iter), (_btree_id),	\

				  (_start), (_flags));			\

	     (_k) = bch2_btree_iter_peek_upto_type(&(_iter), _end, _flags),\

	     !((_ret) = bkey_err(_k)) && (_k).k;			\

	     bch2_btree_iter_advance(&(_iter)))



#define for_each_btree_key_continue(_trans, _iter, _flags, _k, _ret)	\

	for (;								\

	     (_k) = __bch2_btree_iter_peek_and_restart((_trans), &(_iter), _flags),\

fs/bcachefs/btree_update_leaf.c

+3 −2
Original line number Diff line number Diff line
@@ -1286,7 +1286,7 @@ int bch2_trans_update_extent(struct btree_trans *trans, 
			     BTREE_ITER_INTENT|

			     BTREE_ITER_WITH_UPDATES|

			     BTREE_ITER_NOT_EXTENTS);

	k = bch2_btree_iter_peek(&iter);

	k = bch2_btree_iter_peek_upto(&iter, POS(insert->k.p.inode, U64_MAX));

	if ((ret = bkey_err(k)))

		goto err;

	if (!k.k)
@@ -1405,7 +1405,8 @@ int bch2_trans_update_extent(struct btree_trans *trans, 
			goto out;

		}

next:

		k = bch2_btree_iter_next(&iter);

		bch2_btree_iter_advance(&iter);

		k = bch2_btree_iter_peek_upto(&iter, POS(insert->k.p.inode, U64_MAX));

		if ((ret = bkey_err(k)))

			goto err;

		if (!k.k)

fs/bcachefs/dirent.c

+6 −11
Original line number Diff line number Diff line
@@ -470,16 +470,13 @@ int bch2_empty_dir_trans(struct btree_trans *trans, subvol_inum dir) 
	if (ret)

		return ret;



	for_each_btree_key_norestart(trans, iter, BTREE_ID_dirents,

			   SPOS(dir.inum, 0, snapshot), 0, k, ret) {

		if (k.k->p.inode > dir.inum)

			break;



	for_each_btree_key_upto_norestart(trans, iter, BTREE_ID_dirents,

			   SPOS(dir.inum, 0, snapshot),

			   POS(dir.inum, U64_MAX), 0, k, ret)

		if (k.k->type == KEY_TYPE_dirent) {

			ret = -ENOTEMPTY;

			break;

		}

	}

	bch2_trans_iter_exit(trans, &iter);



	return ret;
@@ -503,11 +500,9 @@ int bch2_readdir(struct bch_fs *c, subvol_inum inum, struct dir_context *ctx) 
	if (ret)

		goto err;



	for_each_btree_key_norestart(&trans, iter, BTREE_ID_dirents,

			   SPOS(inum.inum, ctx->pos, snapshot), 0, k, ret) {

		if (k.k->p.inode > inum.inum)

			break;



	for_each_btree_key_upto_norestart(&trans, iter, BTREE_ID_dirents,

			   SPOS(inum.inum, ctx->pos, snapshot),

			   POS(inum.inum, U64_MAX), 0, k, ret) {

		if (k.k->type != KEY_TYPE_dirent)

			continue;

fs/bcachefs/fs.c

+2 −3
Original line number Diff line number Diff line
@@ -936,9 +936,8 @@ static int bch2_fiemap(struct inode *vinode, struct fiemap_extent_info *info, 
			     SPOS(ei->v.i_ino, start, snapshot), 0);



	while (!(ret = btree_trans_too_many_iters(&trans)) &&

	       (k = bch2_btree_iter_peek(&iter)).k &&

	       !(ret = bkey_err(k)) &&

	       bkey_cmp(iter.pos, end) < 0) {

	       (k = bch2_btree_iter_peek_upto(&iter, end)).k &&

	       !(ret = bkey_err(k))) {

		enum btree_id data_btree = BTREE_ID_extents;



		if (!bkey_extent_is_data(k.k) &&