From 5e0e879926c1ce7e1f5e0dfaacaf2d105f7d8a05 Mon Sep 17 00:00:00 2001 From: Qu Wenruo Date: Tue, 22 Aug 2023 13:50:51 +0800 Subject: [PATCH] btrfs: fix a compilation error if DEBUG is defined in btree_dirty_folio [BUG] After commit 72a69cd03082 ("btrfs: subpage: pack all subpage bitmaps into a larger bitmap"), the DEBUG section of btree_dirty_folio() would no longer compile. [CAUSE] If DEBUG is defined, we would do extra checks for btree_dirty_folio(), mostly to make sure the range we marked dirty has an extent buffer and that extent buffer is dirty. For subpage, we need to iterate through all the extent buffers covered by that page range, and make sure they all matches the criteria. However commit 72a69cd03082 ("btrfs: subpage: pack all subpage bitmaps into a larger bitmap") changes how we store the bitmap, we pack all the 16 bits bitmaps into a larger bitmap, which would save some space. This means we no longer have btrfs_subpage::dirty_bitmap, instead the dirty bitmap is starting at btrfs_subpage_info::dirty_offset, and has a length of btrfs_subpage_info::bitmap_nr_bits. [FIX] Although I'm not sure if it still makes sense to maintain such code, at least let it compile. This patch would let us test the bits one by one through the bitmaps. CC: stable@vger.kernel.org # 6.1+ Signed-off-by: Qu Wenruo Signed-off-by: David Sterba --- fs/btrfs/disk-io.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index 639f1e308e4c..68f60d50e1fd 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -520,6 +520,7 @@ static bool btree_dirty_folio(struct address_space *mapping, struct folio *folio) { struct btrfs_fs_info *fs_info = btrfs_sb(mapping->host->i_sb); + struct btrfs_subpage_info *spi = fs_info->subpage_info; struct btrfs_subpage *subpage; struct extent_buffer *eb; int cur_bit = 0; @@ -533,18 +534,19 @@ static bool btree_dirty_folio(struct address_space *mapping, btrfs_assert_tree_write_locked(eb); return filemap_dirty_folio(mapping, folio); } + + ASSERT(spi); subpage = folio_get_private(folio); - ASSERT(subpage->dirty_bitmap); - while (cur_bit < BTRFS_SUBPAGE_BITMAP_SIZE) { + for (cur_bit = spi->dirty_offset; + cur_bit < spi->dirty_offset + spi->bitmap_nr_bits; + cur_bit++) { unsigned long flags; u64 cur; - u16 tmp = (1 << cur_bit); spin_lock_irqsave(&subpage->lock, flags); - if (!(tmp & subpage->dirty_bitmap)) { + if (!test_bit(cur_bit, subpage->bitmaps)) { spin_unlock_irqrestore(&subpage->lock, flags); - cur_bit++; continue; } spin_unlock_irqrestore(&subpage->lock, flags); @@ -557,7 +559,7 @@ static bool btree_dirty_folio(struct address_space *mapping, btrfs_assert_tree_write_locked(eb); free_extent_buffer(eb); - cur_bit += (fs_info->nodesize >> fs_info->sectorsize_bits); + cur_bit += (fs_info->nodesize >> fs_info->sectorsize_bits) - 1; } return filemap_dirty_folio(mapping, folio); } -- 2.20.1