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Currently we abuse the extent_map structure for two purposes: 1) To actually represent extents for inodes; 2) To represent chunk mappings. This is odd and has several disadvantages: 1) To create a chunk map, we need to do two memory allocations: one for an extent_map structure and another one for a map_lookup structure, so more potential for an allocation failure and more complicated code to manage and link two structures; 2) For a chunk map we actually only use 3 fields (24 bytes) of the respective extent map structure: the 'start' field to have the logical start address of the chunk, the 'len' field to have the chunk's size, and the 'orig_block_len' field to contain the chunk's stripe size. Besides wasting a memory, it's also odd and not intuitive at all to have the stripe size in a field named 'orig_block_len'. We are also using 'block_len' of the extent_map structure to contain the chunk size, so we have 2 fields for the same value, 'len' and 'block_len', which is pointless; 3) When an extent map is associated to a chunk mapping, we set the bit EXTENT_FLAG_FS_MAPPING on its flags and then make its member named 'map_lookup' point to the associated map_lookup structure. This means that for an extent map associated to an inode extent, we are not using this 'map_lookup' pointer, so wasting 8 bytes (on a 64 bits platform); 4) Extent maps associated to a chunk mapping are never merged or split so it's pointless to use the existing extent map infrastructure. So add a dedicated data structure named 'btrfs_chunk_map' to represent chunk mappings, this is basically the existing map_lookup structure with some extra fields: 1) 'start' to contain the chunk logical address; 2) 'chunk_len' to contain the chunk's length; 3) 'stripe_size' for the stripe size; 4) 'rb_node' for insertion into a rb tree; 5) 'refs' for reference counting. This way we do a single memory allocation for chunk mappings and we don't waste memory for them with unused/unnecessary fields from an extent_map. We also save 8 bytes from the extent_map structure by removing the 'map_lookup' pointer, so the size of struct extent_map is reduced from 144 bytes down to 136 bytes, and we can now have 30 extents map per 4K page instead of 28. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
59 lines
1.8 KiB
C
59 lines
1.8 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Copyright (C) 2013 Fusion IO. All rights reserved.
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*/
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#ifndef BTRFS_TESTS_H
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#define BTRFS_TESTS_H
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#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
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int btrfs_run_sanity_tests(void);
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#define test_msg(fmt, ...) pr_info("BTRFS: selftest: " fmt "\n", ##__VA_ARGS__)
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#define test_err(fmt, ...) pr_err("BTRFS: selftest: %s:%d " fmt "\n", \
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__FILE__, __LINE__, ##__VA_ARGS__)
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#define test_std_err(index) test_err("%s", test_error[index])
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enum {
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TEST_ALLOC_FS_INFO,
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TEST_ALLOC_ROOT,
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TEST_ALLOC_EXTENT_BUFFER,
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TEST_ALLOC_PATH,
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TEST_ALLOC_INODE,
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TEST_ALLOC_BLOCK_GROUP,
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TEST_ALLOC_EXTENT_MAP,
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TEST_ALLOC_CHUNK_MAP,
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};
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extern const char *test_error[];
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struct btrfs_root;
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struct btrfs_trans_handle;
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int btrfs_test_extent_buffer_operations(u32 sectorsize, u32 nodesize);
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int btrfs_test_free_space_cache(u32 sectorsize, u32 nodesize);
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int btrfs_test_extent_io(u32 sectorsize, u32 nodesize);
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int btrfs_test_inodes(u32 sectorsize, u32 nodesize);
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int btrfs_test_qgroups(u32 sectorsize, u32 nodesize);
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int btrfs_test_free_space_tree(u32 sectorsize, u32 nodesize);
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int btrfs_test_extent_map(void);
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struct inode *btrfs_new_test_inode(void);
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struct btrfs_fs_info *btrfs_alloc_dummy_fs_info(u32 nodesize, u32 sectorsize);
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void btrfs_free_dummy_fs_info(struct btrfs_fs_info *fs_info);
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void btrfs_free_dummy_root(struct btrfs_root *root);
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struct btrfs_block_group *
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btrfs_alloc_dummy_block_group(struct btrfs_fs_info *fs_info, unsigned long length);
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void btrfs_free_dummy_block_group(struct btrfs_block_group *cache);
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void btrfs_init_dummy_trans(struct btrfs_trans_handle *trans,
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struct btrfs_fs_info *fs_info);
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struct btrfs_device *btrfs_alloc_dummy_device(struct btrfs_fs_info *fs_info);
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#else
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static inline int btrfs_run_sanity_tests(void)
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{
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return 0;
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}
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#endif
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#endif
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