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a5ce5d2198
We have the infrastructure to cache extent buffers but we don't actually do the caching. As soon as the last reference is dropped, the buffer is dropped. This patch keeps the extent buffers around until the max cache size is reached (defaults to 25% of memory) and then it drops the last 10% of the LRU to free up cache space for reallocation. The cache size is configurable (for use by e.g. lowmem) when the cache is initialized. Signed-off-by: Jeff Mahoney <jeffm@suse.com> [ update codingstyle, switch total_memory to bytes ] Signed-off-by: David Sterba <dsterba@suse.com>
178 lines
5.9 KiB
C
178 lines
5.9 KiB
C
/*
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* Copyright (C) 2007 Oracle. All rights reserved.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public
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* License v2 as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public
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* License along with this program; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 021110-1307, USA.
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*/
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#ifndef __BTRFS_EXTENT_IO_H__
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#define __BTRFS_EXTENT_IO_H__
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#if BTRFS_FLAT_INCLUDES
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#include "kerncompat.h"
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#include "extent-cache.h"
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#include "list.h"
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#else
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#include <btrfs/kerncompat.h>
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#include <btrfs/extent-cache.h>
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#include <btrfs/list.h>
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#endif /* BTRFS_FLAT_INCLUDES */
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#define EXTENT_DIRTY (1U << 0)
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#define EXTENT_WRITEBACK (1U << 1)
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#define EXTENT_UPTODATE (1U << 2)
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#define EXTENT_LOCKED (1U << 3)
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#define EXTENT_NEW (1U << 4)
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#define EXTENT_DELALLOC (1U << 5)
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#define EXTENT_DEFRAG (1U << 6)
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#define EXTENT_DEFRAG_DONE (1U << 7)
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#define EXTENT_BUFFER_FILLED (1U << 8)
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#define EXTENT_CSUM (1U << 9)
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#define EXTENT_BAD_TRANSID (1U << 10)
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#define EXTENT_BUFFER_DUMMY (1U << 11)
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#define EXTENT_IOBITS (EXTENT_LOCKED | EXTENT_WRITEBACK)
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#define BLOCK_GROUP_DATA (1U << 1)
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#define BLOCK_GROUP_METADATA (1U << 2)
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#define BLOCK_GROUP_SYSTEM (1U << 4)
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#define BLOCK_GROUP_DIRTY (1U)
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/*
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* The extent buffer bitmap operations are done with byte granularity instead of
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* word granularity for two reasons:
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* 1. The bitmaps must be little-endian on disk.
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* 2. Bitmap items are not guaranteed to be aligned to a word and therefore a
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* single word in a bitmap may straddle two pages in the extent buffer.
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*/
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#define BIT_BYTE(nr) ((nr) / BITS_PER_BYTE)
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#define BYTE_MASK ((1 << BITS_PER_BYTE) - 1)
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#define BITMAP_FIRST_BYTE_MASK(start) \
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((BYTE_MASK << ((start) & (BITS_PER_BYTE - 1))) & BYTE_MASK)
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#define BITMAP_LAST_BYTE_MASK(nbits) \
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(BYTE_MASK >> (-(nbits) & (BITS_PER_BYTE - 1)))
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static inline int le_test_bit(int nr, const u8 *addr)
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{
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return 1U & (addr[BIT_BYTE(nr)] >> (nr & (BITS_PER_BYTE-1)));
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}
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struct btrfs_fs_info;
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struct extent_io_tree {
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struct cache_tree state;
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struct cache_tree cache;
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struct list_head lru;
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u64 cache_size;
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u64 max_cache_size;
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};
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struct extent_state {
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struct cache_extent cache_node;
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u64 start;
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u64 end;
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int refs;
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unsigned long state;
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u64 xprivate;
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};
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struct extent_buffer {
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struct cache_extent cache_node;
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u64 start;
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u64 dev_bytenr;
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u32 len;
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struct extent_io_tree *tree;
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struct list_head lru;
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struct list_head recow;
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int refs;
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u32 flags;
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int fd;
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char data[] __attribute__((aligned(8)));
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};
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static inline void extent_buffer_get(struct extent_buffer *eb)
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{
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eb->refs++;
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}
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void extent_io_tree_init(struct extent_io_tree *tree);
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void extent_io_tree_init_cache_max(struct extent_io_tree *tree,
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u64 max_cache_size);
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void extent_io_tree_cleanup(struct extent_io_tree *tree);
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int set_extent_bits(struct extent_io_tree *tree, u64 start, u64 end, int bits);
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int clear_extent_bits(struct extent_io_tree *tree, u64 start, u64 end, int bits);
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int find_first_extent_bit(struct extent_io_tree *tree, u64 start,
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u64 *start_ret, u64 *end_ret, int bits);
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int test_range_bit(struct extent_io_tree *tree, u64 start, u64 end,
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int bits, int filled);
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int set_extent_dirty(struct extent_io_tree *tree, u64 start, u64 end);
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int clear_extent_dirty(struct extent_io_tree *tree, u64 start, u64 end);
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static inline int set_extent_buffer_uptodate(struct extent_buffer *eb)
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{
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eb->flags |= EXTENT_UPTODATE;
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return 0;
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}
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static inline int clear_extent_buffer_uptodate(struct extent_buffer *eb)
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{
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eb->flags &= ~EXTENT_UPTODATE;
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return 0;
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}
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static inline int extent_buffer_uptodate(struct extent_buffer *eb)
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{
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if (!eb || IS_ERR(eb))
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return 0;
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if (eb->flags & EXTENT_UPTODATE)
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return 1;
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return 0;
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}
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int set_state_private(struct extent_io_tree *tree, u64 start, u64 xprivate);
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int get_state_private(struct extent_io_tree *tree, u64 start, u64 *xprivate);
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struct extent_buffer *find_extent_buffer(struct extent_io_tree *tree,
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u64 bytenr, u32 blocksize);
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struct extent_buffer *find_first_extent_buffer(struct extent_io_tree *tree,
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u64 start);
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struct extent_buffer *alloc_extent_buffer(struct extent_io_tree *tree,
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u64 bytenr, u32 blocksize);
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struct extent_buffer *btrfs_clone_extent_buffer(struct extent_buffer *src);
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void free_extent_buffer(struct extent_buffer *eb);
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void free_extent_buffer_nocache(struct extent_buffer *eb);
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int read_extent_from_disk(struct extent_buffer *eb,
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unsigned long offset, unsigned long len);
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int write_extent_to_disk(struct extent_buffer *eb);
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int memcmp_extent_buffer(struct extent_buffer *eb, const void *ptrv,
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unsigned long start, unsigned long len);
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void read_extent_buffer(struct extent_buffer *eb, void *dst,
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unsigned long start, unsigned long len);
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void write_extent_buffer(struct extent_buffer *eb, const void *src,
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unsigned long start, unsigned long len);
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void copy_extent_buffer(struct extent_buffer *dst, struct extent_buffer *src,
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unsigned long dst_offset, unsigned long src_offset,
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unsigned long len);
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void memmove_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset,
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unsigned long src_offset, unsigned long len);
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void memset_extent_buffer(struct extent_buffer *eb, char c,
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unsigned long start, unsigned long len);
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int extent_buffer_test_bit(struct extent_buffer *eb, unsigned long start,
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unsigned long nr);
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int set_extent_buffer_dirty(struct extent_buffer *eb);
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int clear_extent_buffer_dirty(struct extent_buffer *eb);
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int read_data_from_disk(struct btrfs_fs_info *info, void *buf, u64 offset,
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u64 bytes, int mirror);
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int write_data_to_disk(struct btrfs_fs_info *info, void *buf, u64 offset,
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u64 bytes, int mirror);
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#endif
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