From: Zhang Yi Date: Tue, 16 Sep 2025 09:33:37 +0000 (+0800) Subject: ext4: wait for ongoing I/O to complete before freeing blocks X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=328a782cb138029182e521c08f50eb1587db955d;p=users%2Fhch%2Fmisc.git 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 --- diff --git a/fs/ext4/ext4_jbd2.c b/fs/ext4/ext4_jbd2.c index b3e9b7bd7978..a0e66bc10093 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; }