From 328a782cb138029182e521c08f50eb1587db955d Mon Sep 17 00:00:00 2001 From: Zhang Yi Date: Tue, 16 Sep 2025 17:33:37 +0800 Subject: [PATCH] ext4: wait for ongoing I/O to complete before freeing blocks When freeing metadata blocks in nojournal mode, ext4_forget() calls bforget() to clear the dirty flag on the buffer_head and remvoe associated mappings. This is acceptable if the metadata has not yet begun to be written back. However, if the write-back has already started but is not yet completed, ext4_forget() will have no effect. Subsequently, ext4_mb_clear_bb() will immediately return the block to the mb allocator. This block can then be reallocated immediately, potentially causing an data corruption issue. Fix this by clearing the buffer's dirty flag and waiting for the ongoing I/O to complete, ensuring that no further writes to stale data will occur. Fixes: 16e08b14a455 ("ext4: cleanup clean_bdev_aliases() calls") Cc: stable@kernel.org Reported-by: Gao Xiang Closes: https://lore.kernel.org/linux-ext4/a9417096-9549-4441-9878-b1955b899b4e@huaweicloud.com/ Signed-off-by: Zhang Yi Reviewed-by: Jan Kara Message-ID: <20250916093337.3161016-3-yi.zhang@huaweicloud.com> Signed-off-by: Theodore Ts'o --- fs/ext4/ext4_jbd2.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/fs/ext4/ext4_jbd2.c b/fs/ext4/ext4_jbd2.c index b3e9b7bd79787..a0e66bc100930 100644 --- a/fs/ext4/ext4_jbd2.c +++ b/fs/ext4/ext4_jbd2.c @@ -280,9 +280,16 @@ int __ext4_forget(const char *where, unsigned int line, handle_t *handle, bh, is_metadata, inode->i_mode, test_opt(inode->i_sb, DATA_FLAGS)); - /* In the no journal case, we can just do a bforget and return */ + /* + * In the no journal case, we should wait for the ongoing buffer + * to complete and do a forget. + */ if (!ext4_handle_valid(handle)) { - bforget(bh); + if (bh) { + clear_buffer_dirty(bh); + wait_on_buffer(bh); + __bforget(bh); + } return 0; } -- 2.47.3