130 строки
4.5 KiB
C
130 строки
4.5 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef BTRFS_SUBPAGE_H
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#define BTRFS_SUBPAGE_H
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#include <linux/spinlock.h>
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/*
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* Maximum page size we support is 64K, minimum sector size is 4K, u16 bitmap
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* is sufficient. Regular bitmap_* is not used due to size reasons.
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*/
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#define BTRFS_SUBPAGE_BITMAP_SIZE 16
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/*
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* Structure to trace status of each sector inside a page, attached to
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* page::private for both data and metadata inodes.
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*/
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struct btrfs_subpage {
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/* Common members for both data and metadata pages */
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spinlock_t lock;
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u16 uptodate_bitmap;
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u16 error_bitmap;
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u16 dirty_bitmap;
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u16 writeback_bitmap;
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/*
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* Both data and metadata needs to track how many readers are for the
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* page.
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* Data relies on @readers to unlock the page when last reader finished.
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* While metadata doesn't need page unlock, it needs to prevent
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* page::private get cleared before the last end_page_read().
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*/
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atomic_t readers;
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union {
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/*
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* Structures only used by metadata
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*
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* @eb_refs should only be operated under private_lock, as it
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* manages whether the subpage can be detached.
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*/
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atomic_t eb_refs;
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/* Structures only used by data */
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struct {
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atomic_t writers;
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/* Tracke pending ordered extent in this sector */
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u16 ordered_bitmap;
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};
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};
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};
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enum btrfs_subpage_type {
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BTRFS_SUBPAGE_METADATA,
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BTRFS_SUBPAGE_DATA,
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};
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int btrfs_attach_subpage(const struct btrfs_fs_info *fs_info,
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struct page *page, enum btrfs_subpage_type type);
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void btrfs_detach_subpage(const struct btrfs_fs_info *fs_info,
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struct page *page);
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/* Allocate additional data where page represents more than one sector */
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int btrfs_alloc_subpage(const struct btrfs_fs_info *fs_info,
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struct btrfs_subpage **ret,
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enum btrfs_subpage_type type);
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void btrfs_free_subpage(struct btrfs_subpage *subpage);
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void btrfs_page_inc_eb_refs(const struct btrfs_fs_info *fs_info,
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struct page *page);
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void btrfs_page_dec_eb_refs(const struct btrfs_fs_info *fs_info,
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struct page *page);
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void btrfs_subpage_start_reader(const struct btrfs_fs_info *fs_info,
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struct page *page, u64 start, u32 len);
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void btrfs_subpage_end_reader(const struct btrfs_fs_info *fs_info,
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struct page *page, u64 start, u32 len);
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void btrfs_subpage_start_writer(const struct btrfs_fs_info *fs_info,
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struct page *page, u64 start, u32 len);
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bool btrfs_subpage_end_and_test_writer(const struct btrfs_fs_info *fs_info,
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struct page *page, u64 start, u32 len);
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int btrfs_page_start_writer_lock(const struct btrfs_fs_info *fs_info,
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struct page *page, u64 start, u32 len);
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void btrfs_page_end_writer_lock(const struct btrfs_fs_info *fs_info,
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struct page *page, u64 start, u32 len);
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/*
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* Template for subpage related operations.
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*
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* btrfs_subpage_*() are for call sites where the page has subpage attached and
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* the range is ensured to be inside the page.
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*
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* btrfs_page_*() are for call sites where the page can either be subpage
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* specific or regular page. The function will handle both cases.
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* But the range still needs to be inside the page.
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*
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* btrfs_page_clamp_*() are similar to btrfs_page_*(), except the range doesn't
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* need to be inside the page. Those functions will truncate the range
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* automatically.
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*/
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#define DECLARE_BTRFS_SUBPAGE_OPS(name) \
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void btrfs_subpage_set_##name(const struct btrfs_fs_info *fs_info, \
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struct page *page, u64 start, u32 len); \
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void btrfs_subpage_clear_##name(const struct btrfs_fs_info *fs_info, \
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struct page *page, u64 start, u32 len); \
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bool btrfs_subpage_test_##name(const struct btrfs_fs_info *fs_info, \
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struct page *page, u64 start, u32 len); \
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void btrfs_page_set_##name(const struct btrfs_fs_info *fs_info, \
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struct page *page, u64 start, u32 len); \
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void btrfs_page_clear_##name(const struct btrfs_fs_info *fs_info, \
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struct page *page, u64 start, u32 len); \
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bool btrfs_page_test_##name(const struct btrfs_fs_info *fs_info, \
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struct page *page, u64 start, u32 len); \
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void btrfs_page_clamp_set_##name(const struct btrfs_fs_info *fs_info, \
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struct page *page, u64 start, u32 len); \
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void btrfs_page_clamp_clear_##name(const struct btrfs_fs_info *fs_info, \
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struct page *page, u64 start, u32 len); \
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bool btrfs_page_clamp_test_##name(const struct btrfs_fs_info *fs_info, \
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struct page *page, u64 start, u32 len);
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DECLARE_BTRFS_SUBPAGE_OPS(uptodate);
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DECLARE_BTRFS_SUBPAGE_OPS(error);
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DECLARE_BTRFS_SUBPAGE_OPS(dirty);
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DECLARE_BTRFS_SUBPAGE_OPS(writeback);
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DECLARE_BTRFS_SUBPAGE_OPS(ordered);
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bool btrfs_subpage_clear_and_test_dirty(const struct btrfs_fs_info *fs_info,
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struct page *page, u64 start, u32 len);
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#endif
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