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[ Upstream commitc2d6fd9d6f] There is a long-standing metadata corruption issue that happens from time to time, but it's very difficult to reproduce and analyse, benefit from the JBD2_CYCLE_RECORD option, we found out that the problem is the checkpointing process miss to write out some buffers which are raced by another do_get_write_access(). Looks below for detail. jbd2_log_do_checkpoint() //transaction X //buffer A is dirty and not belones to any transaction __buffer_relink_io() //move it to the IO list __flush_batch() write_dirty_buffer() do_get_write_access() clear_buffer_dirty __jbd2_journal_file_buffer() //add buffer A to a new transaction Y lock_buffer(bh) //doesn't write out __jbd2_journal_remove_checkpoint() //finish checkpoint except buffer A //filesystem corrupt if the new transaction Y isn't fully write out. Due to the t_checkpoint_list walking loop in jbd2_log_do_checkpoint() have already handles waiting for buffers under IO and re-added new transaction to complete commit, and it also removing cleaned buffers, this makes sure the list will eventually get empty. So it's fine to leave buffers on the t_checkpoint_list while flushing out and completely stop using the t_checkpoint_io_list. Cc: stable@vger.kernel.org Suggested-by: Jan Kara <jack@suse.cz> Signed-off-by: Zhang Yi <yi.zhang@huawei.com> Tested-by: Zhihao Cheng <chengzhihao1@huawei.com> Reviewed-by: Jan Kara <jack@suse.cz> Link: https://lore.kernel.org/r/20230606135928.434610-2-yi.zhang@huaweicloud.com Signed-off-by: Theodore Ts'o <tytso@mit.edu> Stable-dep-of:e34c8dd238("jbd2: Fix wrongly judgement for buffer head removing while doing checkpoint") Signed-off-by: Sasha Levin <sashal@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.