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07e1ce096d
rb_first_cached() trades an extra pointer "leftmost" for doing the same job as rb_first() but in O(1). As evict_inode_truncate_pages() removes all extent mapping by always looking for the first rb entry, it's helpful to use rb_first_cached instead. For more details about the optimization see patch "Btrfs: delayed-refs: use rb_first_cached for href_root". Tested-by: Holger Hoffstätte <holger@applied-asynchrony.com> Signed-off-by: Liu Bo <bo.liu@linux.alibaba.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
374 lines
9.5 KiB
C
374 lines
9.5 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (C) 2017 Oracle. All rights reserved.
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*/
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#include <linux/types.h>
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#include "btrfs-tests.h"
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#include "../ctree.h"
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static void free_extent_map_tree(struct extent_map_tree *em_tree)
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{
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struct extent_map *em;
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struct rb_node *node;
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while (!RB_EMPTY_ROOT(&em_tree->map.rb_root)) {
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node = rb_first_cached(&em_tree->map);
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em = rb_entry(node, struct extent_map, rb_node);
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remove_extent_mapping(em_tree, em);
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#ifdef CONFIG_BTRFS_DEBUG
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if (refcount_read(&em->refs) != 1) {
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test_err(
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"em leak: em (start 0x%llx len 0x%llx block_start 0x%llx block_len 0x%llx) refs %d",
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em->start, em->len, em->block_start,
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em->block_len, refcount_read(&em->refs));
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refcount_set(&em->refs, 1);
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}
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#endif
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free_extent_map(em);
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}
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}
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/*
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* Test scenario:
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*
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* Suppose that no extent map has been loaded into memory yet, there is a file
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* extent [0, 16K), followed by another file extent [16K, 20K), two dio reads
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* are entering btrfs_get_extent() concurrently, t1 is reading [8K, 16K), t2 is
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* reading [0, 8K)
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*
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* t1 t2
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* btrfs_get_extent() btrfs_get_extent()
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* -> lookup_extent_mapping() ->lookup_extent_mapping()
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* -> add_extent_mapping(0, 16K)
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* -> return em
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* ->add_extent_mapping(0, 16K)
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* -> #handle -EEXIST
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*/
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static void test_case_1(struct btrfs_fs_info *fs_info,
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struct extent_map_tree *em_tree)
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{
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struct extent_map *em;
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u64 start = 0;
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u64 len = SZ_8K;
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int ret;
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em = alloc_extent_map();
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if (!em)
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/* Skip the test on error. */
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return;
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/* Add [0, 16K) */
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em->start = 0;
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em->len = SZ_16K;
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em->block_start = 0;
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em->block_len = SZ_16K;
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ret = add_extent_mapping(em_tree, em, 0);
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ASSERT(ret == 0);
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free_extent_map(em);
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/* Add [16K, 20K) following [0, 16K) */
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em = alloc_extent_map();
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if (!em)
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goto out;
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em->start = SZ_16K;
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em->len = SZ_4K;
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em->block_start = SZ_32K; /* avoid merging */
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em->block_len = SZ_4K;
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ret = add_extent_mapping(em_tree, em, 0);
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ASSERT(ret == 0);
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free_extent_map(em);
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em = alloc_extent_map();
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if (!em)
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goto out;
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/* Add [0, 8K), should return [0, 16K) instead. */
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em->start = start;
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em->len = len;
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em->block_start = start;
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em->block_len = len;
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ret = btrfs_add_extent_mapping(fs_info, em_tree, &em, em->start, em->len);
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if (ret)
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test_err("case1 [%llu %llu]: ret %d", start, start + len, ret);
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if (em &&
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(em->start != 0 || extent_map_end(em) != SZ_16K ||
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em->block_start != 0 || em->block_len != SZ_16K))
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test_err(
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"case1 [%llu %llu]: ret %d return a wrong em (start %llu len %llu block_start %llu block_len %llu",
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start, start + len, ret, em->start, em->len,
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em->block_start, em->block_len);
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free_extent_map(em);
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out:
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/* free memory */
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free_extent_map_tree(em_tree);
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}
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/*
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* Test scenario:
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*
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* Reading the inline ending up with EEXIST, ie. read an inline
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* extent and discard page cache and read it again.
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*/
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static void test_case_2(struct btrfs_fs_info *fs_info,
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struct extent_map_tree *em_tree)
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{
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struct extent_map *em;
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int ret;
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em = alloc_extent_map();
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if (!em)
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/* Skip the test on error. */
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return;
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/* Add [0, 1K) */
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em->start = 0;
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em->len = SZ_1K;
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em->block_start = EXTENT_MAP_INLINE;
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em->block_len = (u64)-1;
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ret = add_extent_mapping(em_tree, em, 0);
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ASSERT(ret == 0);
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free_extent_map(em);
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/* Add [4K, 4K) following [0, 1K) */
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em = alloc_extent_map();
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if (!em)
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goto out;
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em->start = SZ_4K;
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em->len = SZ_4K;
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em->block_start = SZ_4K;
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em->block_len = SZ_4K;
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ret = add_extent_mapping(em_tree, em, 0);
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ASSERT(ret == 0);
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free_extent_map(em);
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em = alloc_extent_map();
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if (!em)
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goto out;
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/* Add [0, 1K) */
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em->start = 0;
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em->len = SZ_1K;
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em->block_start = EXTENT_MAP_INLINE;
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em->block_len = (u64)-1;
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ret = btrfs_add_extent_mapping(fs_info, em_tree, &em, em->start, em->len);
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if (ret)
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test_err("case2 [0 1K]: ret %d", ret);
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if (em &&
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(em->start != 0 || extent_map_end(em) != SZ_1K ||
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em->block_start != EXTENT_MAP_INLINE || em->block_len != (u64)-1))
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test_err(
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"case2 [0 1K]: ret %d return a wrong em (start %llu len %llu block_start %llu block_len %llu",
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ret, em->start, em->len, em->block_start,
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em->block_len);
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free_extent_map(em);
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out:
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/* free memory */
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free_extent_map_tree(em_tree);
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}
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static void __test_case_3(struct btrfs_fs_info *fs_info,
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struct extent_map_tree *em_tree, u64 start)
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{
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struct extent_map *em;
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u64 len = SZ_4K;
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int ret;
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em = alloc_extent_map();
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if (!em)
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/* Skip this test on error. */
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return;
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/* Add [4K, 8K) */
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em->start = SZ_4K;
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em->len = SZ_4K;
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em->block_start = SZ_4K;
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em->block_len = SZ_4K;
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ret = add_extent_mapping(em_tree, em, 0);
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ASSERT(ret == 0);
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free_extent_map(em);
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em = alloc_extent_map();
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if (!em)
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goto out;
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/* Add [0, 16K) */
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em->start = 0;
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em->len = SZ_16K;
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em->block_start = 0;
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em->block_len = SZ_16K;
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ret = btrfs_add_extent_mapping(fs_info, em_tree, &em, start, len);
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if (ret)
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test_err("case3 [0x%llx 0x%llx): ret %d",
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start, start + len, ret);
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/*
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* Since bytes within em are contiguous, em->block_start is identical to
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* em->start.
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*/
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if (em &&
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(start < em->start || start + len > extent_map_end(em) ||
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em->start != em->block_start || em->len != em->block_len))
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test_err(
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"case3 [0x%llx 0x%llx): ret %d em (start 0x%llx len 0x%llx block_start 0x%llx block_len 0x%llx)",
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start, start + len, ret, em->start, em->len,
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em->block_start, em->block_len);
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free_extent_map(em);
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out:
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/* free memory */
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free_extent_map_tree(em_tree);
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}
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/*
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* Test scenario:
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*
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* Suppose that no extent map has been loaded into memory yet.
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* There is a file extent [0, 16K), two jobs are running concurrently
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* against it, t1 is buffered writing to [4K, 8K) and t2 is doing dio
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* read from [0, 4K) or [8K, 12K) or [12K, 16K).
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*
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* t1 goes ahead of t2 and adds em [4K, 8K) into tree.
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*
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* t1 t2
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* cow_file_range() btrfs_get_extent()
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* -> lookup_extent_mapping()
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* -> add_extent_mapping()
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* -> add_extent_mapping()
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*/
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static void test_case_3(struct btrfs_fs_info *fs_info,
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struct extent_map_tree *em_tree)
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{
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__test_case_3(fs_info, em_tree, 0);
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__test_case_3(fs_info, em_tree, SZ_8K);
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__test_case_3(fs_info, em_tree, (12 * 1024ULL));
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}
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static void __test_case_4(struct btrfs_fs_info *fs_info,
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struct extent_map_tree *em_tree, u64 start)
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{
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struct extent_map *em;
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u64 len = SZ_4K;
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int ret;
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em = alloc_extent_map();
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if (!em)
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/* Skip this test on error. */
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return;
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/* Add [0K, 8K) */
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em->start = 0;
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em->len = SZ_8K;
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em->block_start = 0;
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em->block_len = SZ_8K;
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ret = add_extent_mapping(em_tree, em, 0);
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ASSERT(ret == 0);
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free_extent_map(em);
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em = alloc_extent_map();
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if (!em)
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goto out;
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/* Add [8K, 24K) */
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em->start = SZ_8K;
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em->len = 24 * 1024ULL;
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em->block_start = SZ_16K; /* avoid merging */
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em->block_len = 24 * 1024ULL;
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ret = add_extent_mapping(em_tree, em, 0);
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ASSERT(ret == 0);
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free_extent_map(em);
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em = alloc_extent_map();
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if (!em)
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goto out;
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/* Add [0K, 32K) */
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em->start = 0;
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em->len = SZ_32K;
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em->block_start = 0;
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em->block_len = SZ_32K;
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ret = btrfs_add_extent_mapping(fs_info, em_tree, &em, start, len);
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if (ret)
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test_err("case4 [0x%llx 0x%llx): ret %d",
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start, len, ret);
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if (em &&
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(start < em->start || start + len > extent_map_end(em)))
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test_err(
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"case4 [0x%llx 0x%llx): ret %d, added wrong em (start 0x%llx len 0x%llx block_start 0x%llx block_len 0x%llx)",
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start, len, ret, em->start, em->len, em->block_start,
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em->block_len);
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free_extent_map(em);
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out:
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/* free memory */
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free_extent_map_tree(em_tree);
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}
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/*
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* Test scenario:
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*
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* Suppose that no extent map has been loaded into memory yet.
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* There is a file extent [0, 32K), two jobs are running concurrently
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* against it, t1 is doing dio write to [8K, 32K) and t2 is doing dio
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* read from [0, 4K) or [4K, 8K).
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*
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* t1 goes ahead of t2 and splits em [0, 32K) to em [0K, 8K) and [8K 32K).
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*
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* t1 t2
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* btrfs_get_blocks_direct() btrfs_get_blocks_direct()
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* -> btrfs_get_extent() -> btrfs_get_extent()
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* -> lookup_extent_mapping()
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* -> add_extent_mapping() -> lookup_extent_mapping()
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* # load [0, 32K)
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* -> btrfs_new_extent_direct()
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* -> btrfs_drop_extent_cache()
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* # split [0, 32K)
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* -> add_extent_mapping()
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* # add [8K, 32K)
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* -> add_extent_mapping()
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* # handle -EEXIST when adding
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* # [0, 32K)
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*/
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static void test_case_4(struct btrfs_fs_info *fs_info,
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struct extent_map_tree *em_tree)
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{
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__test_case_4(fs_info, em_tree, 0);
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__test_case_4(fs_info, em_tree, SZ_4K);
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}
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int btrfs_test_extent_map(void)
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{
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struct btrfs_fs_info *fs_info = NULL;
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struct extent_map_tree *em_tree;
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test_msg("running extent_map tests");
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/*
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* Note: the fs_info is not set up completely, we only need
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* fs_info::fsid for the tracepoint.
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*/
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fs_info = btrfs_alloc_dummy_fs_info(PAGE_SIZE, PAGE_SIZE);
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if (!fs_info) {
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test_msg("Couldn't allocate dummy fs info");
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return -ENOMEM;
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}
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em_tree = kzalloc(sizeof(*em_tree), GFP_KERNEL);
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if (!em_tree)
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/* Skip the test on error. */
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goto out;
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extent_map_tree_init(em_tree);
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test_case_1(fs_info, em_tree);
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test_case_2(fs_info, em_tree);
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test_case_3(fs_info, em_tree);
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test_case_4(fs_info, em_tree);
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kfree(em_tree);
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out:
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btrfs_free_dummy_fs_info(fs_info);
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return 0;
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}
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