From d4a362673f8933c5753ae27d78eecb12ad5ab717 Mon Sep 17 00:00:00 2001 From: "Kiselev, Oleg" <okiselev@amazon.com> Date: Wed, 7 Sep 2022 09:25:03 +0000 Subject: [PATCH] ext4: avoid resizing to a partial cluster size stable inclusion from stable-v4.19.256 commit 7bdfb01fc5f6b3696728aeb527c50386e0ee09a1 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I5Q0SQ CVE: NA -------------------------------- [ Upstream commit 69cb8e9d8cd97cdf5e293b26d70a9dee3e35e6bd ] This patch avoids an attempt to resize the filesystem to an unaligned cluster boundary. An online resize to a size that is not integral to cluster size results in the last iteration attempting to grow the fs by a negative amount, which trips a BUG_ON and leaves the fs with a corrupted in-memory superblock. Signed-off-by: Oleg Kiselev <okiselev@amazon.com> Link: https://lore.kernel.org/r/0E92A0AB-4F16-4F1A-94B7-702CC6504FDE@amazon.com Signed-off-by: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Yongqiang Liu <liuyongqiang13@huawei.com> --- fs/ext4/resize.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c index 104093f82704..bc870561e394 100644 --- a/fs/ext4/resize.c +++ b/fs/ext4/resize.c @@ -1973,6 +1973,16 @@ int ext4_resize_fs(struct super_block *sb, ext4_fsblk_t n_blocks_count) } brelse(bh); + /* + * For bigalloc, trim the requested size to the nearest cluster + * boundary to avoid creating an unusable filesystem. We do this + * silently, instead of returning an error, to avoid breaking + * callers that blindly resize the filesystem to the full size of + * the underlying block device. + */ + if (ext4_has_feature_bigalloc(sb)) + n_blocks_count &= ~((1 << EXT4_CLUSTER_BITS(sb)) - 1); + retry: o_blocks_count = ext4_blocks_count(es); -- GitLab