From 1d3777ef388a73e1bed66a26d52a7df83e29aa1c Mon Sep 17 00:00:00 2001 From: Qu Wenruo Date: Fri, 26 May 2023 20:30:53 +0800 Subject: [PATCH] btrfs: subpage: dump extra subpage bitmaps for debug There is a bug report that assert_eb_page_uptodate() gets triggered for free space tree metadata. Without proper dump for the subpage bitmaps it's much harder to debug. Thus this patch would dump all the subpage bitmaps (split them into their own bitmaps) for a easier debugging. The output would look like this: (Dumped after a tree block got read from disk) page:000000006e34bf49 refcount:4 mapcount:0 mapping:0000000067661ac4 index:0x1d1 pfn:0x110e9 memcg:ffff0000d7d62000 aops:btree_aops [btrfs] ino:1 flags: 0x8000000000002002(referenced|private|zone=2) page_type: 0xffffffff() raw: 8000000000002002 0000000000000000 dead000000000122 ffff00000188bed0 raw: 00000000000001d1 ffff0000c7992700 00000004ffffffff ffff0000d7d62000 page dumped because: btrfs subpage dump BTRFS warning (device dm-1): start=30490624 len=16384 page=30474240 bitmaps: uptodate=4-7 error= dirty= writeback= ordered= checked= Reviewed-by: Christoph Hellwig Signed-off-by: Qu Wenruo Reviewed-by: David Sterba Signed-off-by: David Sterba --- fs/btrfs/extent_io.c | 5 +++-- fs/btrfs/subpage.c | 42 ++++++++++++++++++++++++++++++++++++++++++ fs/btrfs/subpage.h | 2 ++ 3 files changed, 47 insertions(+), 2 deletions(-) diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c index 3c7773995d6377..87ee376b3cc812 100644 --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -4262,8 +4262,9 @@ static void assert_eb_page_uptodate(const struct extent_buffer *eb, return; if (fs_info->nodesize < PAGE_SIZE) { - WARN_ON(!btrfs_subpage_test_uptodate(fs_info, page, - eb->start, eb->len)); + if (WARN_ON(!btrfs_subpage_test_uptodate(fs_info, page, + eb->start, eb->len))) + btrfs_subpage_dump_bitmap(fs_info, page, eb->start, eb->len); } else { WARN_ON(!PageUptodate(page)); } diff --git a/fs/btrfs/subpage.c b/fs/btrfs/subpage.c index 045117ca0ddc43..74bc43040531fd 100644 --- a/fs/btrfs/subpage.c +++ b/fs/btrfs/subpage.c @@ -745,3 +745,45 @@ void btrfs_page_unlock_writer(struct btrfs_fs_info *fs_info, struct page *page, /* Have writers, use proper subpage helper to end it */ btrfs_page_end_writer_lock(fs_info, page, start, len); } + +#define GET_SUBPAGE_BITMAP(subpage, subpage_info, name, dst) \ + bitmap_cut(dst, subpage->bitmaps, 0, \ + subpage_info->name##_offset, subpage_info->bitmap_nr_bits) + +void __cold btrfs_subpage_dump_bitmap(const struct btrfs_fs_info *fs_info, + struct page *page, u64 start, u32 len) +{ + struct btrfs_subpage_info *subpage_info = fs_info->subpage_info; + struct btrfs_subpage *subpage; + unsigned long uptodate_bitmap; + unsigned long error_bitmap; + unsigned long dirty_bitmap; + unsigned long writeback_bitmap; + unsigned long ordered_bitmap; + unsigned long checked_bitmap; + unsigned long flags; + + ASSERT(PagePrivate(page) && page->private); + ASSERT(subpage_info); + subpage = (struct btrfs_subpage *)page->private; + + spin_lock_irqsave(&subpage->lock, flags); + GET_SUBPAGE_BITMAP(subpage, subpage_info, uptodate, &uptodate_bitmap); + GET_SUBPAGE_BITMAP(subpage, subpage_info, error, &error_bitmap); + GET_SUBPAGE_BITMAP(subpage, subpage_info, dirty, &dirty_bitmap); + GET_SUBPAGE_BITMAP(subpage, subpage_info, writeback, &writeback_bitmap); + GET_SUBPAGE_BITMAP(subpage, subpage_info, ordered, &ordered_bitmap); + GET_SUBPAGE_BITMAP(subpage, subpage_info, checked, &checked_bitmap); + spin_unlock_irqrestore(&subpage->lock, flags); + + dump_page(page, "btrfs subpage dump"); + btrfs_warn(fs_info, +"start=%llu len=%u page=%llu, bitmaps uptodate=%*pbl error=%*pbl dirty=%*pbl writeback=%*pbl ordered=%*pbl checked=%*pbl", + start, len, page_offset(page), + subpage_info->bitmap_nr_bits, &uptodate_bitmap, + subpage_info->bitmap_nr_bits, &error_bitmap, + subpage_info->bitmap_nr_bits, &dirty_bitmap, + subpage_info->bitmap_nr_bits, &writeback_bitmap, + subpage_info->bitmap_nr_bits, &ordered_bitmap, + subpage_info->bitmap_nr_bits, &checked_bitmap); +} diff --git a/fs/btrfs/subpage.h b/fs/btrfs/subpage.h index 0e80ad33690466..5905caea840970 100644 --- a/fs/btrfs/subpage.h +++ b/fs/btrfs/subpage.h @@ -154,5 +154,7 @@ void btrfs_page_assert_not_dirty(const struct btrfs_fs_info *fs_info, struct page *page); void btrfs_page_unlock_writer(struct btrfs_fs_info *fs_info, struct page *page, u64 start, u32 len); +void __cold btrfs_subpage_dump_bitmap(const struct btrfs_fs_info *fs_info, + struct page *page, u64 start, u32 len); #endif