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Date: Wed, 14 Apr 2021 21:47:32 +0800
From: Zhang Yi <yi.zhang@...wei.com>
To: <linux-ext4@...r.kernel.org>
CC: <linux-fsdevel@...r.kernel.org>, <tytso@....edu>,
<adilger.kernel@...ger.ca>, <jack@...e.cz>, <yi.zhang@...wei.com>,
<yukuai3@...wei.com>
Subject: [RFC PATCH v2 2/7] jbd2: ensure abort the journal if detect IO error when writing original buffer back
Althourh we merged <c044f3d8360> ("jbd2: abort journal if free a async
write error metadata buffer"), there is a race between
jbd2_journal_try_to_free_buffers() and jbd2_journal_destroy(), so the
jbd2_log_do_checkpoint() may still missing to detect the buffer write
io error flag and will end up leading to filesystem inconsistency.
jbd2_journal_try_to_free_buffers() ext4_put_super()
jbd2_journal_destroy()
__jbd2_journal_remove_checkpoint()
detect buffer write error jbd2_log_do_checkpoint()
jbd2_cleanup_journal_tail()
<--- lead to inconsistency
jbd2_journal_abort()
Fix this issue by introduce a new mark j_checkpoint_io_error and set it
in __jbd2_journal_remove_checkpoint() when freeing a checkpoint buffer
has write_io_error flag. Then jbd2_journal_destroy() will detect this
mark and abort the journal to prevent updating log tail.
Signed-off-by: Zhang Yi <yi.zhang@...wei.com>
---
fs/jbd2/checkpoint.c | 32 +++++++++++++++++++-------------
fs/jbd2/journal.c | 9 +++++++++
include/linux/jbd2.h | 7 +++++++
3 files changed, 35 insertions(+), 13 deletions(-)
diff --git a/fs/jbd2/checkpoint.c b/fs/jbd2/checkpoint.c
index bf5511d19ac5..ff3d38ad3a1e 100644
--- a/fs/jbd2/checkpoint.c
+++ b/fs/jbd2/checkpoint.c
@@ -221,14 +221,15 @@ int jbd2_log_do_checkpoint(journal_t *journal)
result = jbd2_cleanup_journal_tail(journal);
trace_jbd2_checkpoint(journal, result);
jbd_debug(1, "cleanup_journal_tail returned %d\n", result);
- if (result <= 0)
+ if (result == 0)
return result;
+ if (result < 0)
+ goto error;
/*
* OK, we need to start writing disk blocks. Take one transaction
* and write it.
*/
- result = 0;
spin_lock(&journal->j_list_lock);
if (!journal->j_checkpoint_transactions)
goto out;
@@ -295,8 +296,6 @@ int jbd2_log_do_checkpoint(journal_t *journal)
goto restart;
}
if (!buffer_dirty(bh)) {
- if (unlikely(buffer_write_io_error(bh)) && !result)
- result = -EIO;
BUFFER_TRACE(bh, "remove from checkpoint");
if (__jbd2_journal_remove_checkpoint(jh))
/* The transaction was released; we're done */
@@ -356,9 +355,6 @@ int jbd2_log_do_checkpoint(journal_t *journal)
spin_lock(&journal->j_list_lock);
goto restart2;
}
- if (unlikely(buffer_write_io_error(bh)) && !result)
- result = -EIO;
-
/*
* Now in whatever state the buffer currently is, we
* know that it has been written out and so we can
@@ -369,12 +365,13 @@ int jbd2_log_do_checkpoint(journal_t *journal)
}
out:
spin_unlock(&journal->j_list_lock);
- if (result < 0)
+ result = jbd2_cleanup_journal_tail(journal);
+ if (result >= 0)
+ return 0;
+error:
+ if (!is_journal_aborted(journal))
jbd2_journal_abort(journal, result);
- else
- result = jbd2_cleanup_journal_tail(journal);
-
- return (result < 0) ? result : 0;
+ return result;
}
/*
@@ -400,7 +397,7 @@ int jbd2_cleanup_journal_tail(journal_t *journal)
tid_t first_tid;
unsigned long blocknr;
- if (is_journal_aborted(journal))
+ if (is_journal_aborted(journal) || journal->j_checkpoint_io_error)
return -EIO;
if (!jbd2_journal_get_log_tail(journal, &first_tid, &blocknr))
@@ -564,6 +561,7 @@ int __jbd2_journal_remove_checkpoint(struct journal_head *jh)
struct transaction_chp_stats_s *stats;
transaction_t *transaction;
journal_t *journal;
+ struct buffer_head *bh = jh2bh(jh);
JBUFFER_TRACE(jh, "entry");
@@ -575,6 +573,14 @@ int __jbd2_journal_remove_checkpoint(struct journal_head *jh)
journal = transaction->t_journal;
JBUFFER_TRACE(jh, "removing from transaction");
+ /*
+ * If the buffer has been failed to write out to disk, it may probably
+ * lead to filesystem inconsistency after remove it from the log, so
+ * mark the journal checkpoint write back IO error.
+ */
+ if (buffer_write_io_error(bh))
+ journal->j_checkpoint_io_error = true;
+
__buffer_unlink(jh);
jh->b_cp_transaction = NULL;
jbd2_journal_put_journal_head(jh);
diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index 2dc944442802..6dbeab8b9feb 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -1995,6 +1995,15 @@ int jbd2_journal_destroy(journal_t *journal)
J_ASSERT(journal->j_checkpoint_transactions == NULL);
spin_unlock(&journal->j_list_lock);
+ /*
+ * OK, all checkpoint transactions have been checked, now check the
+ * write out io error flag and abort the journal if some buffer failed
+ * to write back to the original location, otherwise the filesystem
+ * may probably becomes inconsistency.
+ */
+ if (!is_journal_aborted(journal) && journal->j_checkpoint_io_error)
+ jbd2_journal_abort(journal, -EIO);
+
if (journal->j_sb_buffer) {
if (!is_journal_aborted(journal)) {
mutex_lock_io(&journal->j_checkpoint_mutex);
diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h
index 99d3cd051ac3..53ca70f80ad8 100644
--- a/include/linux/jbd2.h
+++ b/include/linux/jbd2.h
@@ -841,6 +841,13 @@ struct journal_s
*/
transaction_t *j_checkpoint_transactions;
+ /**
+ * @j_checkpoint_io_error:
+ *
+ * Detect io error while writing back original buffer to disk.
+ */
+ bool j_checkpoint_io_error;
+
/**
* @j_wait_transaction_locked:
*
--
2.25.4
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