From e4f9434749d85aa99e7e58edce2e003951d8e8e1 Mon Sep 17 00:00:00 2001 From: Qu Wenruo Date: Mon, 27 Sep 2021 15:21:49 +0800 Subject: [PATCH] btrfs: subpage: add bitmap for PageChecked flag Although in btrfs we have very limited usage of PageChecked flag, it's still some page flag not yet subpage compatible. Fix it by introducing btrfs_subpage::checked_offset to do the convert. For most call sites, especially for free-space cache, COW fixup and btrfs_invalidatepage(), they all work in full page mode anyway. For other call sites, they work as subpage compatible mode. Some call sites need extra modification: - btrfs_drop_pages() Needs extra parameter to get the real range we need to clear checked flag. Also since btrfs_drop_pages() will accept pages beyond the dirtied range, update btrfs_subpage_clamp_range() to handle such case by setting @len to 0 if the page is beyond target range. - btrfs_invalidatepage() We need to call subpage helper before calling __btrfs_releasepage(), or it will trigger ASSERT() as page->private will be cleared. - btrfs_verify_data_csum() In theory we don't need the io_bio->csum check anymore, but it's won't hurt. Just change the comment. Signed-off-by: Qu Wenruo Signed-off-by: David Sterba --- fs/btrfs/compression.c | 10 ++++++-- fs/btrfs/file.c | 17 ++++++++++---- fs/btrfs/free-space-cache.c | 6 ++++- fs/btrfs/inode.c | 28 ++++++++++------------ fs/btrfs/reflink.c | 2 +- fs/btrfs/subpage.c | 47 +++++++++++++++++++++++++++++++++++-- fs/btrfs/subpage.h | 2 ++ 7 files changed, 85 insertions(+), 27 deletions(-) diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c index deb5d6061b3c..891a62403534 100644 --- a/fs/btrfs/compression.c +++ b/fs/btrfs/compression.c @@ -296,8 +296,14 @@ static void end_compressed_bio_read(struct bio *bio) * checked so the end_io handlers know about it */ ASSERT(!bio_flagged(bio, BIO_CLONED)); - bio_for_each_segment_all(bvec, cb->orig_bio, iter_all) - SetPageChecked(bvec->bv_page); + bio_for_each_segment_all(bvec, cb->orig_bio, iter_all) { + u64 bvec_start = page_offset(bvec->bv_page) + + bvec->bv_offset; + + btrfs_page_set_checked(btrfs_sb(cb->inode->i_sb), + bvec->bv_page, bvec_start, + bvec->bv_len); + } bio_endio(cb->orig_bio); } diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c index 6c50561f932f..38e878946761 100644 --- a/fs/btrfs/file.c +++ b/fs/btrfs/file.c @@ -437,9 +437,15 @@ static noinline int btrfs_copy_from_user(loff_t pos, size_t write_bytes, /* * unlocks pages after btrfs_file_write is done with them */ -static void btrfs_drop_pages(struct page **pages, size_t num_pages) +static void btrfs_drop_pages(struct btrfs_fs_info *fs_info, + struct page **pages, size_t num_pages, + u64 pos, u64 copied) { size_t i; + u64 block_start = round_down(pos, fs_info->sectorsize); + u64 block_len = round_up(pos + copied, fs_info->sectorsize) - block_start; + + ASSERT(block_len <= U32_MAX); for (i = 0; i < num_pages; i++) { /* page checked is some magic around finding pages that * have been modified without going through btrfs_set_page_dirty @@ -447,7 +453,8 @@ static void btrfs_drop_pages(struct page **pages, size_t num_pages) * accessed as prepare_pages should have marked them accessed * in prepare_pages via find_or_create_page() */ - ClearPageChecked(pages[i]); + btrfs_page_clamp_clear_checked(fs_info, pages[i], block_start, + block_len); unlock_page(pages[i]); put_page(pages[i]); } @@ -504,7 +511,7 @@ int btrfs_dirty_pages(struct btrfs_inode *inode, struct page **pages, struct page *p = pages[i]; btrfs_page_clamp_set_uptodate(fs_info, p, start_pos, num_bytes); - ClearPageChecked(p); + btrfs_page_clamp_clear_checked(fs_info, p, start_pos, num_bytes); btrfs_page_clamp_set_dirty(fs_info, p, start_pos, num_bytes); } @@ -1843,7 +1850,7 @@ static noinline ssize_t btrfs_buffered_write(struct kiocb *iocb, btrfs_delalloc_release_extents(BTRFS_I(inode), reserve_bytes); if (ret) { - btrfs_drop_pages(pages, num_pages); + btrfs_drop_pages(fs_info, pages, num_pages, pos, copied); break; } @@ -1851,7 +1858,7 @@ static noinline ssize_t btrfs_buffered_write(struct kiocb *iocb, if (only_release_metadata) btrfs_check_nocow_unlock(BTRFS_I(inode)); - btrfs_drop_pages(pages, num_pages); + btrfs_drop_pages(fs_info, pages, num_pages, pos, copied); cond_resched(); diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c index 0d26819b1cf6..f3fee88c8ee0 100644 --- a/fs/btrfs/free-space-cache.c +++ b/fs/btrfs/free-space-cache.c @@ -22,6 +22,7 @@ #include "delalloc-space.h" #include "block-group.h" #include "discard.h" +#include "subpage.h" #define BITS_PER_BITMAP (PAGE_SIZE * 8UL) #define MAX_CACHE_BYTES_PER_GIG SZ_64K @@ -411,7 +412,10 @@ static void io_ctl_drop_pages(struct btrfs_io_ctl *io_ctl) for (i = 0; i < io_ctl->num_pages; i++) { if (io_ctl->pages[i]) { - ClearPageChecked(io_ctl->pages[i]); + btrfs_page_clear_checked(io_ctl->fs_info, + io_ctl->pages[i], + page_offset(io_ctl->pages[i]), + PAGE_SIZE); unlock_page(io_ctl->pages[i]); put_page(io_ctl->pages[i]); } diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 9ae417aaea28..2dc064903528 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -2764,7 +2764,7 @@ static void btrfs_writepage_fixup_worker(struct btrfs_work *work) clear_page_dirty_for_io(page); SetPageError(page); } - ClearPageChecked(page); + btrfs_page_clear_checked(inode->root->fs_info, page, page_start, PAGE_SIZE); unlock_page(page); put_page(page); kfree(fixup); @@ -2819,7 +2819,7 @@ int btrfs_writepage_cow_fixup(struct page *page) * page->mapping outside of the page lock. */ ihold(inode); - SetPageChecked(page); + btrfs_page_set_checked(fs_info, page, page_offset(page), PAGE_SIZE); get_page(page); btrfs_init_work(&fixup->work, btrfs_writepage_fixup_worker, NULL, NULL); fixup->page = page; @@ -3269,27 +3269,22 @@ unsigned int btrfs_verify_data_csum(struct btrfs_bio *bbio, u64 start, u64 end) { struct inode *inode = page->mapping->host; + struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb); struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree; struct btrfs_root *root = BTRFS_I(inode)->root; const u32 sectorsize = root->fs_info->sectorsize; u32 pg_off; unsigned int result = 0; - if (PageChecked(page)) { - ClearPageChecked(page); + if (btrfs_page_test_checked(fs_info, page, start, end + 1 - start)) { + btrfs_page_clear_checked(fs_info, page, start, end + 1 - start); return 0; } /* - * For subpage case, above PageChecked is not safe as it's not subpage - * compatible. - * But for now only cow fixup and compressed read utilize PageChecked - * flag, while in this context we can easily use bbio->csum to - * determine if we really need to do csum verification. - * - * So for now, just exit if bbio->csum is NULL, as it means it's - * compressed read, and its compressed data csum has already been - * verified. + * This only happens for NODATASUM or compressed read. + * Normally this should be covered by above check for compressed read + * or the next check for NODATASUM. Just do a quicker exit here. */ if (bbio->csum == NULL) return 0; @@ -5110,7 +5105,8 @@ int btrfs_truncate_block(struct btrfs_inode *inode, loff_t from, loff_t len, len); flush_dcache_page(page); } - ClearPageChecked(page); + btrfs_page_clear_checked(fs_info, page, block_start, + block_end + 1 - block_start); btrfs_page_set_dirty(fs_info, page, block_start, block_end + 1 - block_start); unlock_extent_cached(io_tree, block_start, block_end, &cached_state); @@ -8705,9 +8701,9 @@ static void btrfs_invalidatepage(struct page *page, unsigned int offset, * did something wrong. */ ASSERT(!PageOrdered(page)); + btrfs_page_clear_checked(fs_info, page, page_offset(page), PAGE_SIZE); if (!inode_evicting) __btrfs_releasepage(page, GFP_NOFS); - ClearPageChecked(page); clear_page_extent_mapped(page); } @@ -8851,7 +8847,7 @@ vm_fault_t btrfs_page_mkwrite(struct vm_fault *vmf) memzero_page(page, zero_start, PAGE_SIZE - zero_start); flush_dcache_page(page); } - ClearPageChecked(page); + btrfs_page_clear_checked(fs_info, page, page_start, PAGE_SIZE); btrfs_page_set_dirty(fs_info, page, page_start, end + 1 - page_start); btrfs_page_set_uptodate(fs_info, page, page_start, end + 1 - page_start); diff --git a/fs/btrfs/reflink.c b/fs/btrfs/reflink.c index c71e49782e86..e0f93b357548 100644 --- a/fs/btrfs/reflink.c +++ b/fs/btrfs/reflink.c @@ -138,7 +138,7 @@ static int copy_inline_to_page(struct btrfs_inode *inode, } btrfs_page_set_uptodate(fs_info, page, file_offset, block_size); - ClearPageChecked(page); + btrfs_page_clear_checked(fs_info, page, file_offset, block_size); btrfs_page_set_dirty(fs_info, page, file_offset, block_size); out_unlock: if (page) { diff --git a/fs/btrfs/subpage.c b/fs/btrfs/subpage.c index 51f873a680ea..ed9936cdd267 100644 --- a/fs/btrfs/subpage.c +++ b/fs/btrfs/subpage.c @@ -88,6 +88,9 @@ void btrfs_init_subpage_info(struct btrfs_subpage_info *subpage_info, u32 sector subpage_info->ordered_offset = cur; cur += nr_bits; + subpage_info->checked_offset = cur; + cur += nr_bits; + subpage_info->total_nr_bits = cur; } @@ -255,8 +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, @@ -532,6 +543,36 @@ void btrfs_subpage_clear_ordered(const struct btrfs_fs_info *fs_info, 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. @@ -557,6 +598,7 @@ 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 @@ -627,6 +669,7 @@ 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 diff --git a/fs/btrfs/subpage.h b/fs/btrfs/subpage.h index ac4dd64ed257..46224f959c34 100644 --- a/fs/btrfs/subpage.h +++ b/fs/btrfs/subpage.h @@ -36,6 +36,7 @@ struct btrfs_subpage_info { unsigned int dirty_offset; unsigned int writeback_offset; unsigned int ordered_offset; + unsigned int checked_offset; }; /* @@ -142,6 +143,7 @@ DECLARE_BTRFS_SUBPAGE_OPS(error); DECLARE_BTRFS_SUBPAGE_OPS(dirty); DECLARE_BTRFS_SUBPAGE_OPS(writeback); DECLARE_BTRFS_SUBPAGE_OPS(ordered); +DECLARE_BTRFS_SUBPAGE_OPS(checked); bool btrfs_subpage_clear_and_test_dirty(const struct btrfs_fs_info *fs_info, struct page *page, u64 start, u32 len); -- GitLab