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Message-ID: <lsq.1444349548.503556510@decadent.org.uk>
Date: Fri, 09 Oct 2015 01:12:28 +0100
From: Ben Hutchings <ben@...adent.org.uk>
To: linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC: akpm@...ux-foundation.org, "Roland Dreier" <roland@...nel.org>,
"Eryu Guan" <guaneryu@...il.com>, "Theodore Ts'o" <tytso@....edu>,
"Jan Kara" <jack@...e.com>
Subject: [PATCH 3.2 106/107] jbd2: avoid infinite loop when destroying
aborted journal
3.2.72-rc1 review patch. If anyone has any objections, please let me know.
------------------
From: Jan Kara <jack@...e.com>
commit 841df7df196237ea63233f0f9eaa41db53afd70f upstream.
Commit 6f6a6fda2945 "jbd2: fix ocfs2 corrupt when updating journal
superblock fails" changed jbd2_cleanup_journal_tail() to return EIO
when the journal is aborted. That makes logic in
jbd2_log_do_checkpoint() bail out which is fine, except that
jbd2_journal_destroy() expects jbd2_log_do_checkpoint() to always make
a progress in cleaning the journal. Without it jbd2_journal_destroy()
just loops in an infinite loop.
Fix jbd2_journal_destroy() to cleanup journal checkpoint lists of
jbd2_log_do_checkpoint() fails with error.
Reported-by: Eryu Guan <guaneryu@...il.com>
Tested-by: Eryu Guan <guaneryu@...il.com>
Fixes: 6f6a6fda294506dfe0e3e0a253bb2d2923f28f0a
Signed-off-by: Jan Kara <jack@...e.com>
Signed-off-by: Theodore Ts'o <tytso@....edu>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
Cc: Roland Dreier <roland@...nel.org>
---
--- a/fs/jbd2/checkpoint.c
+++ b/fs/jbd2/checkpoint.c
@@ -509,14 +509,15 @@ int jbd2_cleanup_journal_tail(journal_t
* journal_clean_one_cp_list
*
* Find all the written-back checkpoint buffers in the given list and
- * release them.
+ * release them. If 'destroy' is set, clean all buffers unconditionally.
*
* Called with the journal locked.
* Called with j_list_lock held.
* Returns number of bufers reaped (for debug)
*/
-static int journal_clean_one_cp_list(struct journal_head *jh, int *released)
+static int journal_clean_one_cp_list(struct journal_head *jh, bool destroy,
+ int *released)
{
struct journal_head *last_jh;
struct journal_head *next_jh = jh;
@@ -532,7 +533,10 @@ static int journal_clean_one_cp_list(str
next_jh = jh->b_cpnext;
/* Use trylock because of the ranking */
if (jbd_trylock_bh_state(jh2bh(jh))) {
- ret = __try_to_free_cp_buf(jh);
+ if (!destroy)
+ ret = __try_to_free_cp_buf(jh);
+ else
+ ret = __jbd2_journal_remove_checkpoint(jh) + 1;
if (ret) {
freed++;
if (ret == 2) {
@@ -558,13 +562,14 @@ static int journal_clean_one_cp_list(str
* journal_clean_checkpoint_list
*
* Find all the written-back checkpoint buffers in the journal and release them.
+ * If 'destroy' is set, release all buffers unconditionally.
*
* Called with the journal locked.
* Called with j_list_lock held.
* Returns number of buffers reaped (for debug)
*/
-int __jbd2_journal_clean_checkpoint_list(journal_t *journal)
+int __jbd2_journal_clean_checkpoint_list(journal_t *journal, bool destroy)
{
transaction_t *transaction, *last_transaction, *next_transaction;
int ret = 0;
@@ -580,7 +585,7 @@ int __jbd2_journal_clean_checkpoint_list
transaction = next_transaction;
next_transaction = transaction->t_cpnext;
ret += journal_clean_one_cp_list(transaction->
- t_checkpoint_list, &released);
+ t_checkpoint_list, destroy, &released);
/*
* This function only frees up some memory if possible so we
* dont have an obligation to finish processing. Bail out if
@@ -596,7 +601,7 @@ int __jbd2_journal_clean_checkpoint_list
* we can possibly see not yet submitted buffers on io_list
*/
ret += journal_clean_one_cp_list(transaction->
- t_checkpoint_io_list, &released);
+ t_checkpoint_io_list, destroy, &released);
if (need_resched())
goto out;
} while (transaction != last_transaction);
@@ -605,6 +610,28 @@ out:
}
/*
+ * Remove buffers from all checkpoint lists as journal is aborted and we just
+ * need to free memory
+ */
+void jbd2_journal_destroy_checkpoint(journal_t *journal)
+{
+ /*
+ * We loop because __jbd2_journal_clean_checkpoint_list() may abort
+ * early due to a need of rescheduling.
+ */
+ while (1) {
+ spin_lock(&journal->j_list_lock);
+ if (!journal->j_checkpoint_transactions) {
+ spin_unlock(&journal->j_list_lock);
+ break;
+ }
+ __jbd2_journal_clean_checkpoint_list(journal, true);
+ spin_unlock(&journal->j_list_lock);
+ cond_resched();
+ }
+}
+
+/*
* journal_remove_checkpoint: called after a buffer has been committed
* to disk (either by being write-back flushed to disk, or being
* committed to the log).
--- a/fs/jbd2/commit.c
+++ b/fs/jbd2/commit.c
@@ -435,7 +435,7 @@ void jbd2_journal_commit_transaction(jou
* frees some memory
*/
spin_lock(&journal->j_list_lock);
- __jbd2_journal_clean_checkpoint_list(journal);
+ __jbd2_journal_clean_checkpoint_list(journal, false);
spin_unlock(&journal->j_list_lock);
jbd_debug(3, "JBD2: commit phase 1\n");
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -1571,8 +1571,17 @@ int jbd2_journal_destroy(journal_t *jour
while (journal->j_checkpoint_transactions != NULL) {
spin_unlock(&journal->j_list_lock);
mutex_lock(&journal->j_checkpoint_mutex);
- jbd2_log_do_checkpoint(journal);
+ err = jbd2_log_do_checkpoint(journal);
mutex_unlock(&journal->j_checkpoint_mutex);
+ /*
+ * If checkpointing failed, just free the buffers to avoid
+ * looping forever
+ */
+ if (err) {
+ jbd2_journal_destroy_checkpoint(journal);
+ spin_lock(&journal->j_list_lock);
+ break;
+ }
spin_lock(&journal->j_list_lock);
}
--- a/include/linux/jbd2.h
+++ b/include/linux/jbd2.h
@@ -980,8 +980,9 @@ int __jbd2_update_log_tail(journal_t *jo
extern void jbd2_journal_commit_transaction(journal_t *);
/* Checkpoint list management */
-int __jbd2_journal_clean_checkpoint_list(journal_t *journal);
+int __jbd2_journal_clean_checkpoint_list(journal_t *journal, bool destroy);
int __jbd2_journal_remove_checkpoint(struct journal_head *);
+void jbd2_journal_destroy_checkpoint(journal_t *journal);
void __jbd2_journal_insert_checkpoint(struct journal_head *, transaction_t *);
--
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