From 608c03c0d3e9a1479efeab6a3ddb47276e940f4e Mon Sep 17 00:00:00 2001 From: Zhihao Cheng Date: Tue, 19 Sep 2023 11:07:29 +0800 Subject: [PATCH] jbd2: Fix potential data lost in recovering journal raced with synchronizing fs bdev maillist inclusion category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I828EV CVE: NA Reference: https://lore.kernel.org/linux-ext4/20230911155822.kbg2xayc7ys24kay@quack3/T/#t -------------------------------- JBD2 makes sure journal data is fallen on fs device by sync_blockdev(), however, other process could intercept the EIO information from bdev's mapping, which leads journal recovering successful even EIO occurs during data written back to fs device. We found this problem in our product, iscsi + multipath is chosen for block device of ext4. Unstable network may trigger kpartx to rescan partitions in device mapper layer. Detailed process is shown as following: mount kpartx irq jbd2_journal_recover do_one_pass memcpy(nbh->b_data, obh->b_data) // copy data to fs dev from journal mark_buffer_dirty // mark bh dirty vfs_read generic_file_read_iter // dio filemap_write_and_wait_range __filemap_fdatawrite_range do_writepages block_write_full_folio submit_bh_wbc >> EIO occurs in disk << end_buffer_async_write mark_buffer_write_io_error mapping_set_error set_bit(AS_EIO, &mapping->flags) // set! filemap_check_errors test_and_clear_bit(AS_EIO, &mapping->flags) // clear! err2 = sync_blockdev filemap_write_and_wait filemap_check_errors test_and_clear_bit(AS_EIO, &mapping->flags) // false err2 = 0 Filesystem is mounted successfully even data from journal is failed written into disk, and ext4/ocfs2 could become corrupted. Fix it by comparing the wb_err state in fs block device before recovering and after recovering. Fetch a reproducer in [Link]. Link: https://bugzilla.kernel.org/show_bug.cgi?id=217888 Cc: stable@vger.kernel.org Signed-off-by: Zhihao Cheng Signed-off-by: Zhang Yi (cherry picked from commit 074a0132dd9fcbf4a8d2e0cee540c818db13ee21) --- fs/jbd2/recovery.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/fs/jbd2/recovery.c b/fs/jbd2/recovery.c index 1e07dfac4d81..c267b191f265 100644 --- a/fs/jbd2/recovery.c +++ b/fs/jbd2/recovery.c @@ -286,6 +286,8 @@ int jbd2_journal_recover(journal_t *journal) journal_superblock_t * sb; struct recovery_info info; + errseq_t wb_err; + struct address_space *mapping; memset(&info, 0, sizeof(info)); sb = journal->j_superblock; @@ -303,6 +305,9 @@ int jbd2_journal_recover(journal_t *journal) return 0; } + wb_err = 0; + mapping = journal->j_fs_dev->bd_inode->i_mapping; + errseq_check_and_advance(&mapping->wb_err, &wb_err); err = do_one_pass(journal, &info, PASS_SCAN); if (!err) err = do_one_pass(journal, &info, PASS_REVOKE); @@ -321,6 +326,9 @@ int jbd2_journal_recover(journal_t *journal) jbd2_journal_clear_revoke(journal); err2 = sync_blockdev(journal->j_fs_dev); + if (!err) + err = err2; + err2 = errseq_check_and_advance(&mapping->wb_err, &wb_err); if (!err) err = err2; /* Make sure all replayed data is on permanent storage */ -- Gitee