From 498c74501d1e3546bca42cceae875b3e8c90a1d1 Mon Sep 17 00:00:00 2001 From: Qu Wenruo Date: Wed, 27 Nov 2024 14:14:03 +1030 Subject: [PATCH] btrfs: subpage: dump the involved bitmap when ASSERT() failed For btrfs_folio_assert_not_dirty() and btrfs_folio_set_lock(), we call bitmap_test_range_all_zero() to ensure the involved range has not bit set. However with my recent enhanced delalloc range error handling, I'm hitting the ASSERT() inside btrfs_folio_set_lock(), and is wondering if it's some error handling not properly cleanup the locked bitmap but directly unlock the page. So add some extra dumpping for the ASSERTs to dump the involved bitmap to help debug. Signed-off-by: Qu Wenruo --- fs/btrfs/subpage.c | 41 ++++++++++++++++++++++++++++++----------- 1 file changed, 30 insertions(+), 11 deletions(-) diff --git a/fs/btrfs/subpage.c b/fs/btrfs/subpage.c index 03d7bfc042e2ae..d692bc34a3af8c 100644 --- a/fs/btrfs/subpage.c +++ b/fs/btrfs/subpage.c @@ -635,6 +635,28 @@ IMPLEMENT_BTRFS_PAGE_OPS(ordered, folio_set_ordered, folio_clear_ordered, IMPLEMENT_BTRFS_PAGE_OPS(checked, folio_set_checked, folio_clear_checked, folio_test_checked); +#define GET_SUBPAGE_BITMAP(subpage, fs_info, name, dst) \ +{ \ + const int sectors_per_page = fs_info->sectors_per_page; \ + \ + ASSERT(sectors_per_page < BITS_PER_LONG); \ + *dst = bitmap_read(subpage->bitmaps, \ + sectors_per_page * btrfs_bitmap_nr_##name, \ + sectors_per_page); \ +} + +#define subpage_dump_bitmap(fs_info, folio, name, start, len) \ +{ \ + struct btrfs_subpage *subpage = folio_get_private(folio); \ + unsigned long bitmap; \ + \ + GET_SUBPAGE_BITMAP(subpage, fs_info, name, &bitmap); \ + btrfs_warn(fs_info, \ + "dumpping bitmap start=%llu len=%u folio=%llu" #name "_bitmap=%*pbl", \ + start, len, folio_pos(folio), \ + fs_info->sectors_per_page, &bitmap); \ +} + /* * Make sure not only the page dirty bit is cleared, but also subpage dirty bit * is cleared. @@ -660,6 +682,10 @@ void btrfs_folio_assert_not_dirty(const struct btrfs_fs_info *fs_info, subpage = folio_get_private(folio); ASSERT(subpage); spin_lock_irqsave(&subpage->lock, flags); + if (unlikely(!bitmap_test_range_all_zero(subpage->bitmaps, start_bit, nbits))) { + subpage_dump_bitmap(fs_info, folio, dirty, start, len); + ASSERT(bitmap_test_range_all_zero(subpage->bitmaps, start_bit, nbits)); + } ASSERT(bitmap_test_range_all_zero(subpage->bitmaps, start_bit, nbits)); spin_unlock_irqrestore(&subpage->lock, flags); } @@ -689,23 +715,16 @@ void btrfs_folio_set_lock(const struct btrfs_fs_info *fs_info, nbits = len >> fs_info->sectorsize_bits; spin_lock_irqsave(&subpage->lock, flags); /* Target range should not yet be locked. */ - ASSERT(bitmap_test_range_all_zero(subpage->bitmaps, start_bit, nbits)); + if (unlikely(!bitmap_test_range_all_zero(subpage->bitmaps, start_bit, nbits))) { + subpage_dump_bitmap(fs_info, folio, locked, start, len); + ASSERT(bitmap_test_range_all_zero(subpage->bitmaps, start_bit, nbits)); + } bitmap_set(subpage->bitmaps, start_bit, nbits); ret = atomic_add_return(nbits, &subpage->nr_locked); ASSERT(ret <= fs_info->sectors_per_page); spin_unlock_irqrestore(&subpage->lock, flags); } -#define GET_SUBPAGE_BITMAP(subpage, fs_info, name, dst) \ -{ \ - const int sectors_per_page = fs_info->sectors_per_page; \ - \ - ASSERT(sectors_per_page < BITS_PER_LONG); \ - *dst = bitmap_read(subpage->bitmaps, \ - sectors_per_page * btrfs_bitmap_nr_##name, \ - sectors_per_page); \ -} - void __cold btrfs_subpage_dump_bitmap(const struct btrfs_fs_info *fs_info, struct folio *folio, u64 start, u32 len) {