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btrfs: provide btrfs_page_clamp_*() helpers

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In the coming subpage RW supports, there are a lot of page status update
calls which need to be converted to subpage compatible version, which
needs @start and @len.

Some call sites already have such @start/@len and are already in
page range, like various endio functions.

But there are also call sites which need to clamp the range for subpage
case, like btrfs_dirty_pagse() and __process_contig_pages().

Here we introduce new helpers, btrfs_page_clamp_*(), to do and only do the
clamp for subpage version.

Although in theory all existing btrfs_page_*() calls can be converted to
use btrfs_page_clamp_*() directly, but that would make us to do
unnecessary clamp operations.

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>
This commit is contained in:
Qu Wenruo 2021-05-31 16:50:39 +08:00 committed by David Sterba
parent ed8f13bf4a
commit 60e2d25500
2 changed files with 48 additions and 0 deletions
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38
fs/btrfs/subpage.c
View File

@ -354,6 +354,16 @@ void btrfs_subpage_clear_writeback(const struct btrfs_fs_info *fs_info,
spin_unlock_irqrestore(&subpage->lock, flags);
}
static void btrfs_subpage_clamp_range(struct page *page, u64 *start, u32 *len)
{
u64 orig_start = *start;
u32 orig_len = *len;
*start = max_t(u64, page_offset(page), orig_start);
*len = min_t(u64, page_offset(page) + PAGE_SIZE,
orig_start + orig_len) - *start;
}
/*
* Unlike set/clear which is dependent on each page status, for test all bits
* are tested in the same way.
@ -408,6 +418,34 @@ bool btrfs_page_test_##name(const struct btrfs_fs_info *fs_info, \
if (unlikely(!fs_info) || fs_info->sectorsize == PAGE_SIZE) \
return test_page_func(page); \
return btrfs_subpage_test_##name(fs_info, page, start, len); \
} \
void btrfs_page_clamp_set_##name(const struct btrfs_fs_info *fs_info, \
struct page *page, u64 start, u32 len) \
{ \
if (unlikely(!fs_info) || fs_info->sectorsize == PAGE_SIZE) { \
set_page_func(page); \
return; \
} \
btrfs_subpage_clamp_range(page, &start, &len); \
btrfs_subpage_set_##name(fs_info, page, start, len); \
} \
void btrfs_page_clamp_clear_##name(const struct btrfs_fs_info *fs_info, \
struct page *page, u64 start, u32 len) \
{ \
if (unlikely(!fs_info) || fs_info->sectorsize == PAGE_SIZE) { \
clear_page_func(page); \
return; \
} \
btrfs_subpage_clamp_range(page, &start, &len); \
btrfs_subpage_clear_##name(fs_info, page, start, len); \
} \
bool btrfs_page_clamp_test_##name(const struct btrfs_fs_info *fs_info, \
struct page *page, u64 start, u32 len) \
{ \
if (unlikely(!fs_info) || fs_info->sectorsize == PAGE_SIZE) \
return test_page_func(page); \
btrfs_subpage_clamp_range(page, &start, &len); \
return btrfs_subpage_test_##name(fs_info, page, start, len); \
}
IMPLEMENT_BTRFS_PAGE_OPS(uptodate, SetPageUptodate, ClearPageUptodate,
PageUptodate);

10
fs/btrfs/subpage.h
View File

@ -72,6 +72,10 @@ void btrfs_subpage_end_reader(const struct btrfs_fs_info *fs_info,
* btrfs_page_*() are for call sites where the page can either be subpage
* specific or regular page. The function will handle both cases.
* But the range still needs to be inside the page.
*
* btrfs_page_clamp_*() are similar to btrfs_page_*(), except the range doesn't
* need to be inside the page. Those functions will truncate the range
* automatically.
*/
#define DECLARE_BTRFS_SUBPAGE_OPS(name) \
void btrfs_subpage_set_##name(const struct btrfs_fs_info *fs_info, \
@ -85,6 +89,12 @@ void btrfs_page_set_##name(const struct btrfs_fs_info *fs_info, \
void btrfs_page_clear_##name(const struct btrfs_fs_info *fs_info, \
struct page *page, u64 start, u32 len); \
bool btrfs_page_test_##name(const struct btrfs_fs_info *fs_info, \
struct page *page, u64 start, u32 len); \
void btrfs_page_clamp_set_##name(const struct btrfs_fs_info *fs_info, \
struct page *page, u64 start, u32 len); \
void btrfs_page_clamp_clear_##name(const struct btrfs_fs_info *fs_info, \
struct page *page, u64 start, u32 len); \
bool btrfs_page_clamp_test_##name(const struct btrfs_fs_info *fs_info, \
struct page *page, u64 start, u32 len);
DECLARE_BTRFS_SUBPAGE_OPS(uptodate);