Merge pull request #98 from versity/zab/move_freed_many_commits

Zab/move freed many commits

kmod/src/alloc.c

@@ -892,12 +892,11 @@ static int find_zone_extent(struct super_block *sb, struct scoutfs_alloc_root *r
  * -ENOENT is returned if we run out of extents in the source tree
  * before moving the total.
  *
- * If meta_reserved is non-zero then -EINPROGRESS can be returned if the
- * current meta allocator's avail blocks or room for freed blocks would
- * have fallen under the reserved amount.  The could have been
- * successfully dirtied in this case but the number of blocks moved is
- * not returned.  The caller is expected to deal with the partial
- * progress by commiting the dirty trees and examining the resulting
+ * If meta_budget is non-zero then -EINPROGRESS can be returned if the
+ * the caller's budget is consumed in the allocator during this call
+ * (though not necessarily by us, we don't have per-thread tracking of
+ * allocator consumption :/).  The call can still have made progress and
+ * caller is expected commit the dirty trees and examining the resulting
  * modified trees to see if they need to continue moving extents.
  *
  * The caller can specify that extents in the source tree should first
@@ -914,7 +913,7 @@ int scoutfs_alloc_move(struct super_block *sb, struct scoutfs_alloc *alloc,
 		       struct scoutfs_block_writer *wri,
 		       struct scoutfs_alloc_root *dst,
 		       struct scoutfs_alloc_root *src, u64 total,
-		       __le64 *exclusive, __le64 *vacant, u64 zone_blocks, u64 meta_reserved)
+		       __le64 *exclusive, __le64 *vacant, u64 zone_blocks, u64 meta_budget)
 {
 	struct alloc_ext_args args = {
 		.alloc = alloc,
@@ -922,6 +921,8 @@ int scoutfs_alloc_move(struct super_block *sb, struct scoutfs_alloc *alloc,
 	};
 	struct scoutfs_extent found;
 	struct scoutfs_extent ext;
+	u32 avail_start = 0;
+	u32 freed_start = 0;
 	u64 moved = 0;
 	u64 count;
 	int ret = 0;
@@ -932,6 +933,9 @@ int scoutfs_alloc_move(struct super_block *sb, struct scoutfs_alloc *alloc,
 		vacant = NULL;
 	}
 
+	if (meta_budget != 0)
+		scoutfs_alloc_meta_remaining(alloc, &avail_start, &freed_start);
+
 	while (moved < total) {
 		count = total - moved;
 
@@ -964,10 +968,10 @@ int scoutfs_alloc_move(struct super_block *sb, struct scoutfs_alloc *alloc,
 		if (ret < 0)
 			break;
 
-		if (meta_reserved != 0 &&
-		    scoutfs_alloc_meta_low(sb, alloc, meta_reserved +
-					   extent_mod_blocks(src->root.height) +
-					   extent_mod_blocks(dst->root.height))) {
+		if (meta_budget != 0 &&
+		    scoutfs_alloc_meta_low_since(alloc, avail_start, freed_start, meta_budget,
+						 extent_mod_blocks(src->root.height) +
+						 extent_mod_blocks(dst->root.height))) {
 			ret = -EINPROGRESS;
 			break;
 		}
@@ -1351,6 +1355,27 @@ void scoutfs_alloc_meta_remaining(struct scoutfs_alloc *alloc, u32 *avail_total,
 	} while (read_seqretry(&alloc->seqlock, seq));
 }
 
+/*
+ * Returns true if the caller's consumption of nr from either avail or
+ * freed would end up exceeding their budget relative to the starting
+ * remaining snapshot they took.
+ */
+bool scoutfs_alloc_meta_low_since(struct scoutfs_alloc *alloc, u32 avail_start, u32 freed_start,
+				  u32 budget, u32 nr)
+{
+	u32 avail_use;
+	u32 freed_use;
+	u32 avail;
+	u32 freed;
+
+	scoutfs_alloc_meta_remaining(alloc, &avail, &freed);
+
+	avail_use = avail_start - avail;
+	freed_use = freed_start - freed;
+
+	return ((avail_use + nr) > budget) || ((freed_use + nr) > budget);
+}
+
 bool scoutfs_alloc_test_flag(struct super_block *sb,
 			    struct scoutfs_alloc *alloc, u32 flag)
 {

kmod/src/alloc.h

@@ -131,7 +131,7 @@ int scoutfs_alloc_move(struct super_block *sb, struct scoutfs_alloc *alloc,
 		       struct scoutfs_block_writer *wri,
 		       struct scoutfs_alloc_root *dst,
 		       struct scoutfs_alloc_root *src, u64 total,
-		       __le64 *exclusive, __le64 *vacant, u64 zone_blocks, u64 meta_reserved);
+		       __le64 *exclusive, __le64 *vacant, u64 zone_blocks, u64 meta_budget);
 int scoutfs_alloc_insert(struct super_block *sb, struct scoutfs_alloc *alloc,
 			 struct scoutfs_block_writer *wri, struct scoutfs_alloc_root *root,
 			 u64 start, u64 len);
@@ -159,6 +159,8 @@ int scoutfs_alloc_splice_list(struct super_block *sb,
 bool scoutfs_alloc_meta_low(struct super_block *sb,
 			    struct scoutfs_alloc *alloc, u32 nr);
 void scoutfs_alloc_meta_remaining(struct scoutfs_alloc *alloc, u32 *avail_total, u32 *freed_space);
+bool scoutfs_alloc_meta_low_since(struct scoutfs_alloc *alloc, u32 avail_start, u32 freed_start,
+				  u32 budget, u32 nr);
 bool scoutfs_alloc_test_flag(struct super_block *sb,
 			    struct scoutfs_alloc *alloc, u32 flag);
 

kmod/src/inode.c

@@ -1685,6 +1685,7 @@ static int try_delete_inode_items(struct super_block *sb, u64 ino)
 	struct scoutfs_lock *lock = NULL;
 	struct scoutfs_inode sinode;
 	struct scoutfs_key key;
+	bool clear_trying = false;
 	u64 group_nr;
 	int bit_nr;
 	int ret;
@@ -1704,6 +1705,7 @@ static int try_delete_inode_items(struct super_block *sb, u64 ino)
 		ret = 0;
 		goto out;
 	}
+	clear_trying = true;
 
 	/* can't delete if it's cached in local or remote mounts */
 	if (scoutfs_omap_test(sb, ino) || test_bit_le(bit_nr, ldata->map.bits)) {
@@ -1730,7 +1732,7 @@ static int try_delete_inode_items(struct super_block *sb, u64 ino)
 
 	ret = delete_inode_items(sb, ino, &sinode, lock, orph_lock);
 out:
-	if (ldata)
+	if (clear_trying)
 		clear_bit(bit_nr, ldata->trying);
 
 	scoutfs_unlock(sb, lock, SCOUTFS_LOCK_WRITE);

kmod/src/server.c

@@ -694,13 +694,13 @@ static int alloc_move_refill_zoned(struct super_block *sb, struct scoutfs_alloc_
 
 static int alloc_move_empty(struct super_block *sb,
 			    struct scoutfs_alloc_root *dst,
-			    struct scoutfs_alloc_root *src, u64 meta_reserved)
+			    struct scoutfs_alloc_root *src, u64 meta_budget)
 {
 	DECLARE_SERVER_INFO(sb, server);
 
 	return scoutfs_alloc_move(sb, &server->alloc, &server->wri,
 				  dst, src, le64_to_cpu(src->total_len), NULL, NULL, 0,
-				  meta_reserved);
+				  meta_budget);
 }
 
 /*
@@ -1226,6 +1226,82 @@ static int finalize_and_start_log_merge(struct super_block *sb, struct scoutfs_l
 	return ret;
 }
 
+/*
+ * The calling get_log_trees ran out of available blocks in its commit's
+ * metadata allocator while moving extents from the log tree's
+ * data_freed into the core data_avail.  This finishes moving the
+ * extents in as many additional commits as it takes.   The logs mutex
+ * is nested inside holding commits so we recheck the persistent item
+ * each time we commit to make sure it's still what we think.   The
+ * caller is still going to send the item to the client so we update the
+ * caller's each time we make progress.  This is a best-effort attempt
+ * to clean up and it's valid to leave extents in data_freed we don't
+ * return errors to the caller.  The client will continue the work later
+ * in get_log_trees or as the rid is reclaimed.
+ */
+static void try_drain_data_freed(struct super_block *sb, struct scoutfs_log_trees *lt)
+{
+	DECLARE_SERVER_INFO(sb, server);
+	struct scoutfs_super_block *super = &SCOUTFS_SB(sb)->super;
+	const u64 rid = le64_to_cpu(lt->rid);
+	const u64 nr = le64_to_cpu(lt->nr);
+	struct scoutfs_log_trees drain;
+	struct scoutfs_key key;
+	COMMIT_HOLD(hold);
+	int ret = 0;
+	int err;
+
+	scoutfs_key_init_log_trees(&key, rid, nr);
+
+	while (lt->data_freed.total_len != 0) {
+		server_hold_commit(sb, &hold);
+		mutex_lock(&server->logs_mutex);
+
+		ret = find_log_trees_item(sb, &super->logs_root, false, rid, U64_MAX, &drain);
+		if (ret < 0)
+			break;
+
+		/* careful to only keep draining the caller's specific open trans */
+		if (drain.nr != lt->nr || drain.get_trans_seq != lt->get_trans_seq ||
+		    drain.commit_trans_seq != lt->commit_trans_seq || drain.flags != lt->flags) {
+			ret = -ENOENT;
+			break;
+		}
+
+		ret = scoutfs_btree_dirty(sb, &server->alloc, &server->wri,
+					  &super->logs_root, &key);
+		if (ret < 0)
+			break;
+
+		/* moving can modify and return errors, always update caller and item */
+		mutex_lock(&server->alloc_mutex);
+		ret = alloc_move_empty(sb, &super->data_alloc, &drain.data_freed,
+				       COMMIT_HOLD_ALLOC_BUDGET / 2);
+		mutex_unlock(&server->alloc_mutex);
+		if (ret == -EINPROGRESS)
+			ret = 0;
+
+		*lt = drain;
+		err = scoutfs_btree_force(sb, &server->alloc, &server->wri,
+					  &super->logs_root, &key, &drain, sizeof(drain));
+		BUG_ON(err < 0); /* dirtying must guarantee success */
+
+		mutex_unlock(&server->logs_mutex);
+
+		ret = server_apply_commit(sb, &hold, ret);
+		if (ret < 0) {
+			ret = 0; /* don't try to abort, ignoring ret */
+			break;
+		}
+	}
+
+	/* try to cleanly abort and write any partial dirty btree blocks, but ignore result */
+	if (ret < 0) {
+		mutex_unlock(&server->logs_mutex);
+		server_apply_commit(sb, &hold, 0);
+	}
+}
+
 /*
  * Give the client roots to all the trees that they'll use to build
  * their transaction.
@@ -1351,7 +1427,9 @@ static int server_get_log_trees(struct super_block *sb,
 		goto update;
 	}
 
-	ret = alloc_move_empty(sb, &super->data_alloc, &lt.data_freed, 0);
+	ret = alloc_move_empty(sb, &super->data_alloc, &lt.data_freed, 100);
+	if (ret == -EINPROGRESS)
+		ret = 0;
 	if (ret < 0) {
 		err_str = "emptying committed data_freed";
 		goto update;
@@ -1429,6 +1507,10 @@ out:
 		scoutfs_err(sb, "error %d getting log trees for rid %016llx: %s",
 			    ret, rid, err_str);
 
+	/* try to drain excessive data_freed with additional commits, if needed, ignoring err */
+	if (ret == 0)
+		try_drain_data_freed(sb, &lt);
+
 	return scoutfs_net_response(sb, conn, cmd, id, ret, &lt, sizeof(lt));
 }
 

tests/Makefile

@@ -10,7 +10,8 @@ BIN := src/createmany			\
 	src/bulk_create_paths		\
 	src/stage_tmpfile		\
 	src/find_xattrs			\
-	src/create_xattr_loop
+	src/create_xattr_loop		\
+	src/fragmented_data_extents
 
 DEPS := $(wildcard src/*.d)
 

tests/golden/large-fragmented-free

@@ -0,0 +1,3 @@
+== creating fragmented extents
+== unlink file with moved extents to free extents per block
+== cleanup

tests/sequence

@@ -9,6 +9,7 @@ fallocate.sh
 setattr_more.sh
 offline-extent-waiting.sh
 move-blocks.sh
+large-fragmented-free.sh
 enospc.sh
 srch-basic-functionality.sh
 simple-xattr-unit.sh

tests/src/fragmented_data_extents.c

@@ -0,0 +1,113 @@
+/*
+ * Copyright (C) 2021 Versity Software, Inc.  All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ */
+
+/*
+ * This creates fragmented data extents.
+ *
+ * A file is created that has alternating free and allocated extents.
+ * This also results in the global allocator having the matching
+ * fragmented free extent pattern.  While that file is being created,
+ * occasionally an allocated extent is moved to another file.   This
+ * results in a file that has fragmented extents at a given stride that
+ * can be deleted to create free data extents with a given stride.
+ *
+ * We don't have hole punching so to do this quickly we use a goofy
+ * combination of fallocate, truncate, and our move_blocks ioctl.
+ */
+
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#endif
+#include <unistd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/ioctl.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <linux/types.h>
+#include <assert.h>
+
+#include "ioctl.h"
+
+#define BLOCK_SIZE 4096
+
+int main(int argc, char **argv)
+{
+	struct scoutfs_ioctl_move_blocks mb = {0,};
+	unsigned long long freed_extents;
+	unsigned long long move_stride;
+	unsigned long long i;
+	int alloc_fd;
+	int trunc_fd;
+	off_t off;
+	int ret;
+
+	if (argc != 5) {
+		printf("%s <freed_extents> <move_stride> <alloc_file> <trunc_file>\n", argv[0]);
+		return 1;
+	}
+
+	freed_extents = strtoull(argv[1], NULL, 0);
+	move_stride = strtoull(argv[2], NULL, 0);
+
+	alloc_fd = open(argv[3], O_RDWR | O_CREAT | O_TRUNC, S_IRUSR | S_IWUSR);
+	if (alloc_fd == -1) {
+		fprintf(stderr, "error opening %s: %d (%s)\n", argv[3], errno, strerror(errno));
+		exit(1);
+	}
+
+	trunc_fd = open(argv[4], O_RDWR | O_CREAT | O_TRUNC, S_IRUSR | S_IWUSR);
+	if (trunc_fd == -1) {
+		fprintf(stderr, "error opening %s: %d (%s)\n", argv[4], errno, strerror(errno));
+		exit(1);
+	}
+
+	for (i = 0, off = 0; i < freed_extents; i++, off += BLOCK_SIZE * 2) {
+
+		ret = fallocate(alloc_fd, 0, off, BLOCK_SIZE * 2);
+		if (ret < 0) {
+			fprintf(stderr, "fallocate at off %llu error: %d (%s)\n",
+				(unsigned long long)off, errno, strerror(errno));
+			exit(1);
+		}
+
+		ret = ftruncate(alloc_fd, off + BLOCK_SIZE);
+		if (ret < 0) {
+			fprintf(stderr, "truncate to off %llu error: %d (%s)\n",
+				(unsigned long long)off + BLOCK_SIZE, errno, strerror(errno));
+			exit(1);
+		}
+
+		if ((i % move_stride) == 0) {
+			mb.from_fd = alloc_fd;
+			mb.from_off = off;
+			mb.len = BLOCK_SIZE;
+			mb.to_off = i * BLOCK_SIZE;
+
+			ret = ioctl(trunc_fd, SCOUTFS_IOC_MOVE_BLOCKS, &mb);
+			if (ret < 0) {
+				fprintf(stderr, "move from off %llu error: %d (%s)\n",
+					(unsigned long long)off,
+					errno, strerror(errno));
+			}
+		}
+	}
+
+	if (alloc_fd > -1)
+		close(alloc_fd);
+	if (trunc_fd > -1)
+		close(trunc_fd);
+
+	return 0;
+}

tests/tests/large-fragmented-free.sh

@@ -0,0 +1,22 @@
+#
+# Make sure the server can handle a transaction with a data_freed whose
+# blocks all hit different btree blocks in the main free list.  It
+# probably has to be merged in multiple commits.
+#
+
+t_require_commands fragmented_data_extents
+
+EXTENTS_PER_BTREE_BLOCK=600
+EXTENTS_PER_LIST_BLOCK=8192
+FREED_EXTENTS=$((EXTENTS_PER_BTREE_BLOCK * EXTENTS_PER_LIST_BLOCK))
+
+echo "== creating fragmented extents"
+fragmented_data_extents $FREED_EXTENTS $EXTENTS_PER_BTREE_BLOCK "$T_D0/alloc" "$T_D0/move"
+
+echo "== unlink file with moved extents to free extents per block"
+rm -f "$T_D0/move"
+
+echo "== cleanup"
+rm -f "$T_D0/alloc"
+
+t_pass