1e1de38792
Introduce a new data inodes specific subpage member, writers, to record how many sectors are under page lock for delalloc writing. This member acts pretty much the same as readers, except it's only for delalloc writes. This is important for delalloc code to trace which page can really be freed, as we have cases like run_delalloc_nocow() where we may exit processing nocow range inside a page, but need to exit to do cow half way. In that case, we need a way to determine if we can really unlock a full page. With the new btrfs_subpage::writers, there is a new requirement: - Page locked by process_one_page() must be unlocked by process_one_page() There are still tons of call sites manually lock and unlock a page, without updating btrfs_subpage::writers. So if we lock a page through process_one_page() then it must be unlocked by process_one_page() to keep btrfs_subpage::writers consistent. This will be handled in next patch. Tested-by: Ritesh Harjani <riteshh@linux.ibm.com> # [ppc64] Tested-by: Anand Jain <anand.jain@oracle.com> # [aarch64] Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
119 lines
4.1 KiB
C
119 lines
4.1 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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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 readers;
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atomic_t writers;
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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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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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