--- a/src/objstore/CMakeLists.txt	Mon Dec 19 19:33:52 2022 -0500
+++ b/src/objstore/CMakeLists.txt	Mon Dec 19 19:35:04 2022 -0500
@@ -33,7 +33,7 @@
 	obj_dir_link.c
 	obj_dir_unlink.c
 	obj_ops.c
-	obj_txn.c
+	obj_rw.c
 	objstore.c
 	txn.c
 	vdev.c

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/objstore/obj_rw.c	Mon Dec 19 19:35:04 2022 -0500
@@ -0,0 +1,175 @@
+/*
+ * Copyright (c) 2015-2020,2022 Josef 'Jeff' Sipek <jeffpc@josefsipek.net>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#include <jeffpc/error.h>
+
+#include "objstore_impl.h"
+
+/* returns number of bytes read (if > 0), or negated errno otherwise */
+ssize_t obj_read(struct objver *ver, void *_buf, size_t len,
+		 uint64_t offset)
+{
+	uint8_t *buf = _buf;
+	size_t orig_len;
+	int ret;
+
+	if (offset >= ver->attrs.size)
+		return 0;
+
+	len = MIN(len, ver->attrs.size - offset);
+	orig_len = len;
+
+	while (len) {
+		const uint64_t pgoff = offset & PAGE_OFFSET_MASK;
+		const size_t thislen = MIN(len, PAGE_SIZE - pgoff);
+		struct page *page;
+
+		page = page_lookup(ver, offset / PAGE_SIZE, PG_ALLOC | PG_FILL);
+		if (IS_ERR(page)) {
+			ret = PTR_ERR(page);
+			break;
+		}
+
+		memcpy(buf, &page->ptr[pgoff], thislen);
+
+		page_unlock(page);
+
+		buf += thislen;
+		len -= thislen;
+		offset += thislen;
+	}
+
+	return (orig_len == len) ? ret : (orig_len - len);
+}
+
+static int __obj_write_perform(struct txn *txn, struct txn_entry *entry)
+{
+	const uint64_t last_pgno = entry->write.pgno + entry->write.pgcnt - 1;
+	struct objver *ver = entry->write.ver;
+	uint64_t pgno;
+	int ret;
+
+	for (pgno = entry->write.pgno; pgno <= last_pgno; pgno++) {
+		struct page *page;
+
+		page = page_lookup(ver, pgno, 0);
+		if (IS_ERR(page)) {
+			VERIFY3U(PTR_ERR(page), ==, -ENOENT);
+			continue;
+		}
+
+		/*
+		 * It may have been written out by a previous transaction
+		 * entry in the same transaction.  If that's the case, there
+		 * is no point in writing it out again.  The previous write
+		 * clears the dirty bit, so we use that here to check.
+		 */
+		if (page->dirty) {
+			ret = ver->obj->ops->write_page(ver, page->ptr, pgno);
+			if (ret)
+				goto err;
+
+			page->dirty = false;
+		}
+
+		page_unlock(page);
+	}
+
+	return 0;
+
+err:
+	/* drop the remaining dirty pages */
+	page_inval_range(ver, pgno, last_pgno - pgno + 1);
+
+	return ret;
+}
+
+static void __obj_write_rollback(struct txn *txn, struct txn_entry *entry)
+{
+	/* drop the dirty pages */
+	page_inval_range(entry->write.ver, entry->write.pgno,
+			 entry->write.pgcnt);
+}
+
+static void __obj_write_cleanup(struct txn *txn, struct txn_entry *entry)
+{
+	txn_detach_objver(txn, entry->write.ver);
+}
+
+/* write an arbitrary number of bytes */
+ssize_t obj_write(struct txn *txn, struct objver *ver, const void *_buf,
+		  size_t len, uint64_t offset)
+{
+	const uint8_t *buf = _buf;
+	struct txn_entry *entry;
+	size_t written;
+	int ret;
+
+	ASSERT3U(offset, <, ver->attrs.size);
+	ASSERT3U(offset + len, <=, ver->attrs.size);
+
+	txn_attach_objver(txn, ver);
+
+	entry = txn_alloc_entry(txn);
+	entry->op = OP_WRITE;
+	entry->perform = __obj_write_perform;
+	entry->rollback = __obj_write_rollback;
+	entry->cleanup = __obj_write_cleanup;
+	entry->write.ver = ver;
+	entry->write.pgno = offset / PAGE_SIZE;
+	entry->write.pgcnt = p2roundup(len, PAGE_SIZE) / PAGE_SIZE;
+	txn_log_entry(txn, entry);
+
+	written = 0;
+	ret = 0;
+
+	while (len) {
+		const uint64_t pgoff = offset & PAGE_OFFSET_MASK;
+		const size_t thislen = MIN(len, PAGE_SIZE - pgoff);
+		const bool partial = (thislen != PAGE_SIZE);
+		struct page *page;
+
+		page = page_lookup(ver, offset / PAGE_SIZE,
+				   PG_ALLOC | (partial ? PG_FILL : 0));
+		if (IS_ERR(page)) {
+			ret = PTR_ERR(page);
+			break;
+		}
+
+		memcpy(&page->ptr[pgoff], buf, thislen);
+
+		page->dirty = true;
+
+		page_unlock(page);
+
+		buf += thislen;
+		len -= thislen;
+		offset += thislen;
+		written += thislen;
+	}
+
+	/*
+	 * If we wrote anything out, return number of bytes, otherwise
+	 * return the errno if we failed before we wrote any bytes out.
+	 */
+	return written ? written : ret;
+}

--- a/src/objstore/obj_txn.c	Mon Dec 19 19:33:52 2022 -0500
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,175 +0,0 @@
-/*
- * Copyright (c) 2015-2020,2022 Josef 'Jeff' Sipek <jeffpc@josefsipek.net>
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
- * SOFTWARE.
- */
-
-#include <jeffpc/error.h>
-
-#include "objstore_impl.h"
-
-/* returns number of bytes read (if > 0), or negated errno otherwise */
-ssize_t obj_read(struct objver *ver, void *_buf, size_t len,
-		 uint64_t offset)
-{
-	uint8_t *buf = _buf;
-	size_t orig_len;
-	int ret;
-
-	if (offset >= ver->attrs.size)
-		return 0;
-
-	len = MIN(len, ver->attrs.size - offset);
-	orig_len = len;
-
-	while (len) {
-		const uint64_t pgoff = offset & PAGE_OFFSET_MASK;
-		const size_t thislen = MIN(len, PAGE_SIZE - pgoff);
-		struct page *page;
-
-		page = page_lookup(ver, offset / PAGE_SIZE, PG_ALLOC | PG_FILL);
-		if (IS_ERR(page)) {
-			ret = PTR_ERR(page);
-			break;
-		}
-
-		memcpy(buf, &page->ptr[pgoff], thislen);
-
-		page_unlock(page);
-
-		buf += thislen;
-		len -= thislen;
-		offset += thislen;
-	}
-
-	return (orig_len == len) ? ret : (orig_len - len);
-}
-
-static int __obj_write_perform(struct txn *txn, struct txn_entry *entry)
-{
-	const uint64_t last_pgno = entry->write.pgno + entry->write.pgcnt - 1;
-	struct objver *ver = entry->write.ver;
-	uint64_t pgno;
-	int ret;
-
-	for (pgno = entry->write.pgno; pgno <= last_pgno; pgno++) {
-		struct page *page;
-
-		page = page_lookup(ver, pgno, 0);
-		if (IS_ERR(page)) {
-			VERIFY3U(PTR_ERR(page), ==, -ENOENT);
-			continue;
-		}
-
-		/*
-		 * It may have been written out by a previous transaction
-		 * entry in the same transaction.  If that's the case, there
-		 * is no point in writing it out again.  The previous write
-		 * clears the dirty bit, so we use that here to check.
-		 */
-		if (page->dirty) {
-			ret = ver->obj->ops->write_page(ver, page->ptr, pgno);
-			if (ret)
-				goto err;
-
-			page->dirty = false;
-		}
-
-		page_unlock(page);
-	}
-
-	return 0;
-
-err:
-	/* drop the remaining dirty pages */
-	page_inval_range(ver, pgno, last_pgno - pgno + 1);
-
-	return ret;
-}
-
-static void __obj_write_rollback(struct txn *txn, struct txn_entry *entry)
-{
-	/* drop the dirty pages */
-	page_inval_range(entry->write.ver, entry->write.pgno,
-			 entry->write.pgcnt);
-}
-
-static void __obj_write_cleanup(struct txn *txn, struct txn_entry *entry)
-{
-	txn_detach_objver(txn, entry->write.ver);
-}
-
-/* write an arbitrary number of bytes */
-ssize_t obj_write(struct txn *txn, struct objver *ver, const void *_buf,
-		  size_t len, uint64_t offset)
-{
-	const uint8_t *buf = _buf;
-	struct txn_entry *entry;
-	size_t written;
-	int ret;
-
-	ASSERT3U(offset, <, ver->attrs.size);
-	ASSERT3U(offset + len, <=, ver->attrs.size);
-
-	txn_attach_objver(txn, ver);
-
-	entry = txn_alloc_entry(txn);
-	entry->op = OP_WRITE;
-	entry->perform = __obj_write_perform;
-	entry->rollback = __obj_write_rollback;
-	entry->cleanup = __obj_write_cleanup;
-	entry->write.ver = ver;
-	entry->write.pgno = offset / PAGE_SIZE;
-	entry->write.pgcnt = p2roundup(len, PAGE_SIZE) / PAGE_SIZE;
-	txn_log_entry(txn, entry);
-
-	written = 0;
-	ret = 0;
-
-	while (len) {
-		const uint64_t pgoff = offset & PAGE_OFFSET_MASK;
-		const size_t thislen = MIN(len, PAGE_SIZE - pgoff);
-		const bool partial = (thislen != PAGE_SIZE);
-		struct page *page;
-
-		page = page_lookup(ver, offset / PAGE_SIZE,
-				   PG_ALLOC | (partial ? PG_FILL : 0));
-		if (IS_ERR(page)) {
-			ret = PTR_ERR(page);
-			break;
-		}
-
-		memcpy(&page->ptr[pgoff], buf, thislen);
-
-		page->dirty = true;
-
-		page_unlock(page);
-
-		buf += thislen;
-		len -= thislen;
-		offset += thislen;
-		written += thislen;
-	}
-
-	/*
-	 * If we wrote anything out, return number of bytes, otherwise
-	 * return the errno if we failed before we wrote any bytes out.
-	 */
-	return written ? written : ret;
-}