| From 39fc08ca69160ab2620c010e86eae384af01c180 Mon Sep 17 00:00:00 2001 |
| From: Sasha Levin <sashal@kernel.org> |
| Date: Tue, 15 Jun 2021 17:05:37 +0800 |
| Subject: ext4: fix WARN_ON_ONCE(!buffer_uptodate) after an error writing the |
| superblock |
| |
| From: Ye Bin <yebin10@huawei.com> |
| |
| [ Upstream commit 558d6450c7755aa005d89021204b6cdcae5e848f ] |
| |
| If a writeback of the superblock fails with an I/O error, the buffer |
| is marked not uptodate. However, this can cause a WARN_ON to trigger |
| when we attempt to write superblock a second time. (Which might |
| succeed this time, for cerrtain types of block devices such as iSCSI |
| devices over a flaky network.) |
| |
| Try to detect this case in flush_stashed_error_work(), and also change |
| __ext4_handle_dirty_metadata() so we always set the uptodate flag, not |
| just in the nojournal case. |
| |
| Before this commit, this problem can be repliciated via: |
| |
| 1. dmsetup create dust1 --table '0 2097152 dust /dev/sdc 0 4096' |
| 2. mount /dev/mapper/dust1 /home/test |
| 3. dmsetup message dust1 0 addbadblock 0 10 |
| 4. cd /home/test |
| 5. echo "XXXXXXX" > t |
| |
| After a few seconds, we got following warning: |
| |
| [ 80.654487] end_buffer_async_write: bh=0xffff88842f18bdd0 |
| [ 80.656134] Buffer I/O error on dev dm-0, logical block 0, lost async page write |
| [ 85.774450] EXT4-fs error (device dm-0): ext4_check_bdev_write_error:193: comm kworker/u16:8: Error while async write back metadata |
| [ 91.415513] mark_buffer_dirty: bh=0xffff88842f18bdd0 |
| [ 91.417038] ------------[ cut here ]------------ |
| [ 91.418450] WARNING: CPU: 1 PID: 1944 at fs/buffer.c:1092 mark_buffer_dirty.cold+0x1c/0x5e |
| [ 91.440322] Call Trace: |
| [ 91.440652] __jbd2_journal_temp_unlink_buffer+0x135/0x220 |
| [ 91.441354] __jbd2_journal_unfile_buffer+0x24/0x90 |
| [ 91.441981] __jbd2_journal_refile_buffer+0x134/0x1d0 |
| [ 91.442628] jbd2_journal_commit_transaction+0x249a/0x3240 |
| [ 91.443336] ? put_prev_entity+0x2a/0x200 |
| [ 91.443856] ? kjournald2+0x12e/0x510 |
| [ 91.444324] kjournald2+0x12e/0x510 |
| [ 91.444773] ? woken_wake_function+0x30/0x30 |
| [ 91.445326] kthread+0x150/0x1b0 |
| [ 91.445739] ? commit_timeout+0x20/0x20 |
| [ 91.446258] ? kthread_flush_worker+0xb0/0xb0 |
| [ 91.446818] ret_from_fork+0x1f/0x30 |
| [ 91.447293] ---[ end trace 66f0b6bf3d1abade ]--- |
| |
| Signed-off-by: Ye Bin <yebin10@huawei.com> |
| Link: https://lore.kernel.org/r/20210615090537.3423231-1-yebin10@huawei.com |
| Signed-off-by: Theodore Ts'o <tytso@mit.edu> |
| Signed-off-by: Sasha Levin <sashal@kernel.org> |
| --- |
| fs/ext4/ext4_jbd2.c | 2 +- |
| fs/ext4/super.c | 12 ++++++++++-- |
| 2 files changed, 11 insertions(+), 3 deletions(-) |
| |
| diff --git a/fs/ext4/ext4_jbd2.c b/fs/ext4/ext4_jbd2.c |
| index be799040a415..b96ecba91899 100644 |
| --- a/fs/ext4/ext4_jbd2.c |
| +++ b/fs/ext4/ext4_jbd2.c |
| @@ -327,6 +327,7 @@ int __ext4_handle_dirty_metadata(const char *where, unsigned int line, |
| |
| set_buffer_meta(bh); |
| set_buffer_prio(bh); |
| + set_buffer_uptodate(bh); |
| if (ext4_handle_valid(handle)) { |
| err = jbd2_journal_dirty_metadata(handle, bh); |
| /* Errors can only happen due to aborted journal or a nasty bug */ |
| @@ -355,7 +356,6 @@ int __ext4_handle_dirty_metadata(const char *where, unsigned int line, |
| err); |
| } |
| } else { |
| - set_buffer_uptodate(bh); |
| if (inode) |
| mark_buffer_dirty_inode(bh, inode); |
| else |
| diff --git a/fs/ext4/super.c b/fs/ext4/super.c |
| index 62dd98189e32..265745154945 100644 |
| --- a/fs/ext4/super.c |
| +++ b/fs/ext4/super.c |
| @@ -705,15 +705,23 @@ static void flush_stashed_error_work(struct work_struct *work) |
| * ext4 error handling code during handling of previous errors. |
| */ |
| if (!sb_rdonly(sbi->s_sb) && journal) { |
| + struct buffer_head *sbh = sbi->s_sbh; |
| handle = jbd2_journal_start(journal, 1); |
| if (IS_ERR(handle)) |
| goto write_directly; |
| - if (jbd2_journal_get_write_access(handle, sbi->s_sbh)) { |
| + if (jbd2_journal_get_write_access(handle, sbh)) { |
| jbd2_journal_stop(handle); |
| goto write_directly; |
| } |
| ext4_update_super(sbi->s_sb); |
| - if (jbd2_journal_dirty_metadata(handle, sbi->s_sbh)) { |
| + if (buffer_write_io_error(sbh) || !buffer_uptodate(sbh)) { |
| + ext4_msg(sbi->s_sb, KERN_ERR, "previous I/O error to " |
| + "superblock detected"); |
| + clear_buffer_write_io_error(sbh); |
| + set_buffer_uptodate(sbh); |
| + } |
| + |
| + if (jbd2_journal_dirty_metadata(handle, sbh)) { |
| jbd2_journal_stop(handle); |
| goto write_directly; |
| } |
| -- |
| 2.30.2 |
| |