kernel-hacking-2024-linux-s.../fs/jbd2
zhangyi (F) 7b97d868b7 ext4, jbd2: ensure panic by fix a race between jbd2 abort and ext4 error handlers
In the ext4 filesystem with errors=panic, if one process is recording
errno in the superblock when invoking jbd2_journal_abort() due to some
error cases, it could be raced by another __ext4_abort() which is
setting the SB_RDONLY flag but missing panic because errno has not been
recorded.

jbd2_journal_commit_transaction()
 jbd2_journal_abort()
  journal->j_flags |= JBD2_ABORT;
  jbd2_journal_update_sb_errno()
                                    | ext4_journal_check_start()
                                    |  __ext4_abort()
                                    |   sb->s_flags |= SB_RDONLY;
                                    |   if (!JBD2_REC_ERR)
                                    |        return;
  journal->j_flags |= JBD2_REC_ERR;

Finally, it will no longer trigger panic because the filesystem has
already been set read-only. Fix this by introduce j_abort_mutex to make
sure journal abort is completed before panic, and remove JBD2_REC_ERR
flag.

Fixes: 4327ba52af ("ext4, jbd2: ensure entering into panic after recording an error in superblock")
Signed-off-by: zhangyi (F) <yi.zhang@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20200609073540.3810702-1-yi.zhang@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2020-06-12 14:51:41 -04:00
..
checkpoint.c ext4, jbd2: ensure panic when aborting with zero errno 2020-01-25 02:59:25 -05:00
commit.c jbd2: improve comments about freeing data buffers whose page mapping is NULL 2020-03-05 20:25:05 -05:00
journal.c ext4, jbd2: ensure panic by fix a race between jbd2 abort and ext4 error handlers 2020-06-12 14:51:41 -04:00
Kconfig treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
Makefile treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
recovery.c
revoke.c jbd2: Reserve space for revoke descriptor blocks 2019-11-05 16:00:48 -05:00
transaction.c jbd2: avoid leaking transaction credits when unreserving handle 2020-06-03 23:16:53 -04:00