diff options
Diffstat (limited to 'fs/btrfs/subpage.c')
| -rw-r--r-- | fs/btrfs/subpage.c | 290 |
1 files changed, 226 insertions, 64 deletions
diff --git a/fs/btrfs/subpage.c b/fs/btrfs/subpage.c index cb10e56ee31e..ef7ae20d2b77 100644 --- a/fs/btrfs/subpage.c +++ b/fs/btrfs/subpage.c @@ -63,11 +63,41 @@ * This means a slightly higher tree locking latency. */ +void btrfs_init_subpage_info(struct btrfs_subpage_info *subpage_info, u32 sectorsize) +{ + unsigned int cur = 0; + unsigned int nr_bits; + + ASSERT(IS_ALIGNED(PAGE_SIZE, sectorsize)); + + nr_bits = PAGE_SIZE / sectorsize; + subpage_info->bitmap_nr_bits = nr_bits; + + subpage_info->uptodate_offset = cur; + cur += nr_bits; + + subpage_info->error_offset = cur; + cur += nr_bits; + + subpage_info->dirty_offset = cur; + cur += nr_bits; + + subpage_info->writeback_offset = cur; + cur += nr_bits; + + subpage_info->ordered_offset = cur; + cur += nr_bits; + + subpage_info->checked_offset = cur; + cur += nr_bits; + + subpage_info->total_nr_bits = cur; +} + int btrfs_attach_subpage(const struct btrfs_fs_info *fs_info, struct page *page, enum btrfs_subpage_type type) { - struct btrfs_subpage *subpage = NULL; - int ret; + struct btrfs_subpage *subpage; /* * We have cases like a dummy extent buffer page, which is not mappped @@ -75,13 +105,15 @@ int btrfs_attach_subpage(const struct btrfs_fs_info *fs_info, */ if (page->mapping) ASSERT(PageLocked(page)); + /* Either not subpage, or the page already has private attached */ if (fs_info->sectorsize == PAGE_SIZE || PagePrivate(page)) return 0; - ret = btrfs_alloc_subpage(fs_info, &subpage, type); - if (ret < 0) - return ret; + subpage = btrfs_alloc_subpage(fs_info, type); + if (IS_ERR(subpage)) + return PTR_ERR(subpage); + attach_page_private(page, subpage); return 0; } @@ -100,24 +132,28 @@ void btrfs_detach_subpage(const struct btrfs_fs_info *fs_info, btrfs_free_subpage(subpage); } -int btrfs_alloc_subpage(const struct btrfs_fs_info *fs_info, - struct btrfs_subpage **ret, - enum btrfs_subpage_type type) +struct btrfs_subpage *btrfs_alloc_subpage(const struct btrfs_fs_info *fs_info, + enum btrfs_subpage_type type) { - if (fs_info->sectorsize == PAGE_SIZE) - return 0; + struct btrfs_subpage *ret; + unsigned int real_size; + + ASSERT(fs_info->sectorsize < PAGE_SIZE); + + real_size = struct_size(ret, bitmaps, + BITS_TO_LONGS(fs_info->subpage_info->total_nr_bits)); + ret = kzalloc(real_size, GFP_NOFS); + if (!ret) + return ERR_PTR(-ENOMEM); - *ret = kzalloc(sizeof(struct btrfs_subpage), GFP_NOFS); - if (!*ret) - return -ENOMEM; - spin_lock_init(&(*ret)->lock); + spin_lock_init(&ret->lock); if (type == BTRFS_SUBPAGE_METADATA) { - atomic_set(&(*ret)->eb_refs, 0); + atomic_set(&ret->eb_refs, 0); } else { - atomic_set(&(*ret)->readers, 0); - atomic_set(&(*ret)->writers, 0); + atomic_set(&ret->readers, 0); + atomic_set(&ret->writers, 0); } - return 0; + return ret; } void btrfs_free_subpage(struct btrfs_subpage *subpage) @@ -222,8 +258,16 @@ static void btrfs_subpage_clamp_range(struct page *page, u64 *start, u32 *len) 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; + /* + * For certain call sites like btrfs_drop_pages(), we may have pages + * beyond the target range. In that case, just set @len to 0, subpage + * helpers can handle @len == 0 without any problem. + */ + if (page_offset(page) >= orig_start + orig_len) + *len = 0; + else + *len = min_t(u64, page_offset(page) + PAGE_SIZE, + orig_start + orig_len) - *start; } void btrfs_subpage_start_writer(const struct btrfs_fs_info *fs_info, @@ -248,6 +292,16 @@ bool btrfs_subpage_end_and_test_writer(const struct btrfs_fs_info *fs_info, btrfs_subpage_assert(fs_info, page, start, len); + /* + * We have call sites passing @lock_page into + * extent_clear_unlock_delalloc() for compression path. + * + * This @locked_page is locked by plain lock_page(), thus its + * subpage::writers is 0. Handle them in a special way. + */ + if (atomic_read(&subpage->writers) == 0) + return true; + ASSERT(atomic_read(&subpage->writers) >= nbits); return atomic_sub_and_test(nbits, &subpage->writers); } @@ -289,37 +343,59 @@ void btrfs_page_end_writer_lock(const struct btrfs_fs_info *fs_info, unlock_page(page); } -/* - * Convert the [start, start + len) range into a u16 bitmap - * - * For example: if start == page_offset() + 16K, len = 16K, we get 0x00f0. - */ -static u16 btrfs_subpage_calc_bitmap(const struct btrfs_fs_info *fs_info, - struct page *page, u64 start, u32 len) +static bool bitmap_test_range_all_set(unsigned long *addr, unsigned int start, + unsigned int nbits) { - const int bit_start = offset_in_page(start) >> fs_info->sectorsize_bits; - const int nbits = len >> fs_info->sectorsize_bits; + unsigned int found_zero; - btrfs_subpage_assert(fs_info, page, start, len); + found_zero = find_next_zero_bit(addr, start + nbits, start); + if (found_zero == start + nbits) + return true; + return false; +} - /* - * Here nbits can be 16, thus can go beyond u16 range. We make the - * first left shift to be calculate in unsigned long (at least u32), - * then truncate the result to u16. - */ - return (u16)(((1UL << nbits) - 1) << bit_start); +static bool bitmap_test_range_all_zero(unsigned long *addr, unsigned int start, + unsigned int nbits) +{ + unsigned int found_set; + + found_set = find_next_bit(addr, start + nbits, start); + if (found_set == start + nbits) + return true; + return false; } +#define subpage_calc_start_bit(fs_info, page, name, start, len) \ +({ \ + unsigned int start_bit; \ + \ + btrfs_subpage_assert(fs_info, page, start, len); \ + start_bit = offset_in_page(start) >> fs_info->sectorsize_bits; \ + start_bit += fs_info->subpage_info->name##_offset; \ + start_bit; \ +}) + +#define subpage_test_bitmap_all_set(fs_info, subpage, name) \ + bitmap_test_range_all_set(subpage->bitmaps, \ + fs_info->subpage_info->name##_offset, \ + fs_info->subpage_info->bitmap_nr_bits) + +#define subpage_test_bitmap_all_zero(fs_info, subpage, name) \ + bitmap_test_range_all_zero(subpage->bitmaps, \ + fs_info->subpage_info->name##_offset, \ + fs_info->subpage_info->bitmap_nr_bits) + void btrfs_subpage_set_uptodate(const struct btrfs_fs_info *fs_info, struct page *page, u64 start, u32 len) { struct btrfs_subpage *subpage = (struct btrfs_subpage *)page->private; - const u16 tmp = btrfs_subpage_calc_bitmap(fs_info, page, start, len); + unsigned int start_bit = subpage_calc_start_bit(fs_info, page, + uptodate, start, len); unsigned long flags; spin_lock_irqsave(&subpage->lock, flags); - subpage->uptodate_bitmap |= tmp; - if (subpage->uptodate_bitmap == U16_MAX) + bitmap_set(subpage->bitmaps, start_bit, len >> fs_info->sectorsize_bits); + if (subpage_test_bitmap_all_set(fs_info, subpage, uptodate)) SetPageUptodate(page); spin_unlock_irqrestore(&subpage->lock, flags); } @@ -328,11 +404,12 @@ void btrfs_subpage_clear_uptodate(const struct btrfs_fs_info *fs_info, struct page *page, u64 start, u32 len) { struct btrfs_subpage *subpage = (struct btrfs_subpage *)page->private; - const u16 tmp = btrfs_subpage_calc_bitmap(fs_info, page, start, len); + unsigned int start_bit = subpage_calc_start_bit(fs_info, page, + uptodate, start, len); unsigned long flags; spin_lock_irqsave(&subpage->lock, flags); - subpage->uptodate_bitmap &= ~tmp; + bitmap_clear(subpage->bitmaps, start_bit, len >> fs_info->sectorsize_bits); ClearPageUptodate(page); spin_unlock_irqrestore(&subpage->lock, flags); } @@ -341,11 +418,12 @@ void btrfs_subpage_set_error(const struct btrfs_fs_info *fs_info, struct page *page, u64 start, u32 len) { struct btrfs_subpage *subpage = (struct btrfs_subpage *)page->private; - const u16 tmp = btrfs_subpage_calc_bitmap(fs_info, page, start, len); + unsigned int start_bit = subpage_calc_start_bit(fs_info, page, + error, start, len); unsigned long flags; spin_lock_irqsave(&subpage->lock, flags); - subpage->error_bitmap |= tmp; + bitmap_set(subpage->bitmaps, start_bit, len >> fs_info->sectorsize_bits); SetPageError(page); spin_unlock_irqrestore(&subpage->lock, flags); } @@ -354,12 +432,13 @@ void btrfs_subpage_clear_error(const struct btrfs_fs_info *fs_info, struct page *page, u64 start, u32 len) { struct btrfs_subpage *subpage = (struct btrfs_subpage *)page->private; - const u16 tmp = btrfs_subpage_calc_bitmap(fs_info, page, start, len); + unsigned int start_bit = subpage_calc_start_bit(fs_info, page, + error, start, len); unsigned long flags; spin_lock_irqsave(&subpage->lock, flags); - subpage->error_bitmap &= ~tmp; - if (subpage->error_bitmap == 0) + bitmap_clear(subpage->bitmaps, start_bit, len >> fs_info->sectorsize_bits); + if (subpage_test_bitmap_all_zero(fs_info, subpage, error)) ClearPageError(page); spin_unlock_irqrestore(&subpage->lock, flags); } @@ -368,11 +447,12 @@ void btrfs_subpage_set_dirty(const struct btrfs_fs_info *fs_info, struct page *page, u64 start, u32 len) { struct btrfs_subpage *subpage = (struct btrfs_subpage *)page->private; - u16 tmp = btrfs_subpage_calc_bitmap(fs_info, page, start, len); + unsigned int start_bit = subpage_calc_start_bit(fs_info, page, + dirty, start, len); unsigned long flags; spin_lock_irqsave(&subpage->lock, flags); - subpage->dirty_bitmap |= tmp; + bitmap_set(subpage->bitmaps, start_bit, len >> fs_info->sectorsize_bits); spin_unlock_irqrestore(&subpage->lock, flags); set_page_dirty(page); } @@ -391,13 +471,14 @@ bool btrfs_subpage_clear_and_test_dirty(const struct btrfs_fs_info *fs_info, struct page *page, u64 start, u32 len) { struct btrfs_subpage *subpage = (struct btrfs_subpage *)page->private; - u16 tmp = btrfs_subpage_calc_bitmap(fs_info, page, start, len); + unsigned int start_bit = subpage_calc_start_bit(fs_info, page, + dirty, start, len); unsigned long flags; bool last = false; spin_lock_irqsave(&subpage->lock, flags); - subpage->dirty_bitmap &= ~tmp; - if (subpage->dirty_bitmap == 0) + bitmap_clear(subpage->bitmaps, start_bit, len >> fs_info->sectorsize_bits); + if (subpage_test_bitmap_all_zero(fs_info, subpage, dirty)) last = true; spin_unlock_irqrestore(&subpage->lock, flags); return last; @@ -417,11 +498,12 @@ void btrfs_subpage_set_writeback(const struct btrfs_fs_info *fs_info, struct page *page, u64 start, u32 len) { struct btrfs_subpage *subpage = (struct btrfs_subpage *)page->private; - u16 tmp = btrfs_subpage_calc_bitmap(fs_info, page, start, len); + unsigned int start_bit = subpage_calc_start_bit(fs_info, page, + writeback, start, len); unsigned long flags; spin_lock_irqsave(&subpage->lock, flags); - subpage->writeback_bitmap |= tmp; + bitmap_set(subpage->bitmaps, start_bit, len >> fs_info->sectorsize_bits); set_page_writeback(page); spin_unlock_irqrestore(&subpage->lock, flags); } @@ -430,12 +512,13 @@ void btrfs_subpage_clear_writeback(const struct btrfs_fs_info *fs_info, struct page *page, u64 start, u32 len) { struct btrfs_subpage *subpage = (struct btrfs_subpage *)page->private; - u16 tmp = btrfs_subpage_calc_bitmap(fs_info, page, start, len); + unsigned int start_bit = subpage_calc_start_bit(fs_info, page, + writeback, start, len); unsigned long flags; spin_lock_irqsave(&subpage->lock, flags); - subpage->writeback_bitmap &= ~tmp; - if (subpage->writeback_bitmap == 0) { + bitmap_clear(subpage->bitmaps, start_bit, len >> fs_info->sectorsize_bits); + if (subpage_test_bitmap_all_zero(fs_info, subpage, writeback)) { ASSERT(PageWriteback(page)); end_page_writeback(page); } @@ -446,11 +529,12 @@ void btrfs_subpage_set_ordered(const struct btrfs_fs_info *fs_info, struct page *page, u64 start, u32 len) { struct btrfs_subpage *subpage = (struct btrfs_subpage *)page->private; - const u16 tmp = btrfs_subpage_calc_bitmap(fs_info, page, start, len); + unsigned int start_bit = subpage_calc_start_bit(fs_info, page, + ordered, start, len); unsigned long flags; spin_lock_irqsave(&subpage->lock, flags); - subpage->ordered_bitmap |= tmp; + bitmap_set(subpage->bitmaps, start_bit, len >> fs_info->sectorsize_bits); SetPageOrdered(page); spin_unlock_irqrestore(&subpage->lock, flags); } @@ -459,15 +543,46 @@ void btrfs_subpage_clear_ordered(const struct btrfs_fs_info *fs_info, struct page *page, u64 start, u32 len) { struct btrfs_subpage *subpage = (struct btrfs_subpage *)page->private; - const u16 tmp = btrfs_subpage_calc_bitmap(fs_info, page, start, len); + unsigned int start_bit = subpage_calc_start_bit(fs_info, page, + ordered, start, len); unsigned long flags; spin_lock_irqsave(&subpage->lock, flags); - subpage->ordered_bitmap &= ~tmp; - if (subpage->ordered_bitmap == 0) + bitmap_clear(subpage->bitmaps, start_bit, len >> fs_info->sectorsize_bits); + if (subpage_test_bitmap_all_zero(fs_info, subpage, ordered)) ClearPageOrdered(page); spin_unlock_irqrestore(&subpage->lock, flags); } + +void btrfs_subpage_set_checked(const struct btrfs_fs_info *fs_info, + struct page *page, u64 start, u32 len) +{ + struct btrfs_subpage *subpage = (struct btrfs_subpage *)page->private; + unsigned int start_bit = subpage_calc_start_bit(fs_info, page, + checked, start, len); + unsigned long flags; + + spin_lock_irqsave(&subpage->lock, flags); + bitmap_set(subpage->bitmaps, start_bit, len >> fs_info->sectorsize_bits); + if (subpage_test_bitmap_all_set(fs_info, subpage, checked)) + SetPageChecked(page); + spin_unlock_irqrestore(&subpage->lock, flags); +} + +void btrfs_subpage_clear_checked(const struct btrfs_fs_info *fs_info, + struct page *page, u64 start, u32 len) +{ + struct btrfs_subpage *subpage = (struct btrfs_subpage *)page->private; + unsigned int start_bit = subpage_calc_start_bit(fs_info, page, + checked, start, len); + unsigned long flags; + + spin_lock_irqsave(&subpage->lock, flags); + bitmap_clear(subpage->bitmaps, start_bit, len >> fs_info->sectorsize_bits); + ClearPageChecked(page); + spin_unlock_irqrestore(&subpage->lock, flags); +} + /* * Unlike set/clear which is dependent on each page status, for test all bits * are tested in the same way. @@ -477,12 +592,14 @@ bool btrfs_subpage_test_##name(const struct btrfs_fs_info *fs_info, \ struct page *page, u64 start, u32 len) \ { \ struct btrfs_subpage *subpage = (struct btrfs_subpage *)page->private; \ - const u16 tmp = btrfs_subpage_calc_bitmap(fs_info, page, start, len); \ + unsigned int start_bit = subpage_calc_start_bit(fs_info, page, \ + name, start, len); \ unsigned long flags; \ bool ret; \ \ spin_lock_irqsave(&subpage->lock, flags); \ - ret = ((subpage->name##_bitmap & tmp) == tmp); \ + ret = bitmap_test_range_all_set(subpage->bitmaps, start_bit, \ + len >> fs_info->sectorsize_bits); \ spin_unlock_irqrestore(&subpage->lock, flags); \ return ret; \ } @@ -491,6 +608,7 @@ IMPLEMENT_BTRFS_SUBPAGE_TEST_OP(error); IMPLEMENT_BTRFS_SUBPAGE_TEST_OP(dirty); IMPLEMENT_BTRFS_SUBPAGE_TEST_OP(writeback); IMPLEMENT_BTRFS_SUBPAGE_TEST_OP(ordered); +IMPLEMENT_BTRFS_SUBPAGE_TEST_OP(checked); /* * Note that, in selftests (extent-io-tests), we can have empty fs_info passed @@ -561,6 +679,7 @@ IMPLEMENT_BTRFS_PAGE_OPS(writeback, set_page_writeback, end_page_writeback, PageWriteback); IMPLEMENT_BTRFS_PAGE_OPS(ordered, SetPageOrdered, ClearPageOrdered, PageOrdered); +IMPLEMENT_BTRFS_PAGE_OPS(checked, SetPageChecked, ClearPageChecked, PageChecked); /* * Make sure not only the page dirty bit is cleared, but also subpage dirty bit @@ -579,5 +698,48 @@ void btrfs_page_assert_not_dirty(const struct btrfs_fs_info *fs_info, return; ASSERT(PagePrivate(page) && page->private); - ASSERT(subpage->dirty_bitmap == 0); + ASSERT(subpage_test_bitmap_all_zero(fs_info, subpage, dirty)); +} + +/* + * Handle different locked pages with different page sizes: + * + * - Page locked by plain lock_page() + * It should not have any subpage::writers count. + * Can be unlocked by unlock_page(). + * This is the most common locked page for __extent_writepage() called + * inside extent_write_cache_pages() or extent_write_full_page(). + * Rarer cases include the @locked_page from extent_write_locked_range(). + * + * - Page locked by lock_delalloc_pages() + * There is only one caller, all pages except @locked_page for + * extent_write_locked_range(). + * In this case, we have to call subpage helper to handle the case. + */ +void btrfs_page_unlock_writer(struct btrfs_fs_info *fs_info, struct page *page, + u64 start, u32 len) +{ + struct btrfs_subpage *subpage; + + ASSERT(PageLocked(page)); + /* For regular page size case, we just unlock the page */ + if (fs_info->sectorsize == PAGE_SIZE) + return unlock_page(page); + + ASSERT(PagePrivate(page) && page->private); + subpage = (struct btrfs_subpage *)page->private; + + /* + * For subpage case, there are two types of locked page. With or + * without writers number. + * + * Since we own the page lock, no one else could touch subpage::writers + * and we are safe to do several atomic operations without spinlock. + */ + if (atomic_read(&subpage->writers) == 0) + /* No writers, locked by plain lock_page() */ + return unlock_page(page); + + /* Have writers, use proper subpage helper to end it */ + btrfs_page_end_writer_lock(fs_info, page, start, len); } |