[PATCH 5.18 600/879] ocfs2: fix mounting crash if journal is not alloced

Greg Kroah-Hartman
2022-06-08T01:08:54Z

From: Heming Zhao via Ocfs2-devel <ocfs2-devel@oss.oracle.com>

[ Upstream commit bb20b31dee1a6c329c2f721fbe21c51945cdfc29 ]

Patch series "rewrite error handling during mounting stage".

This patch (of 5):

After commit da5e7c87827e8 ("ocfs2: cleanup journal init and shutdown"),
journal init later than before, it makes NULL pointer access in free
routine.

Crash flow:

ocfs2_fill_super
+ ocfs2_mount_volume
| + ocfs2_dlm_init //fail & return, osb->journal is NULL.
| + ...
| + ocfs2_check_volume //no chance to init osb->journal
|
+ ...
+ ocfs2_dismount_volume
ocfs2_release_system_inodes
...
evict
...
ocfs2_clear_inode
ocfs2_checkpoint_inode
ocfs2_ci_fully_checkpointed
time_after(journal->j_trans_id, ci->ci_last_trans)
+ journal is empty, crash!

For fixing, there are three solutions:

1> Partly revert commit da5e7c87827e8

For avoiding kernel crash, this make sense for us. We only
concerned whether there has any non-system inode access before dlm
init. The answer is NO. And all journal replay/recovery handling
happen after dlm & journal init done. So this method is not graceful
but workable.

2> Add osb->journal check in free inode routine (eg ocfs2_clear_inode)

The fix code is special for mounting phase, but it will continue
working after mounting stage. In another word, this method adds
useless code in normal inode free flow.

3> Do directly free inode in mounting phase

This method is brutal/complex and may introduce unsafe code,
currently maintainer didn't like.

At last, we chose method <1> and did partly reverted job. We reverted
journal init codes, and kept cleanup codes flow.

Link: https://lkml.kernel.org/r/20220424130952.2436-1-heming.zhao@suse.com
Link: https://lkml.kernel.org/r/20220424130952.2436-2-heming.zhao@suse.com
Fixes: da5e7c87827e8 ("ocfs2: cleanup journal init and shutdown")
Signed-off-by: Heming Zhao <heming.zhao@suse.com>
Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Changwei Ge <gechangwei@live.cn>
Cc: Gang He <ghe@suse.com>
Cc: Jun Piao <piaojun@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/ocfs2/inode.c | 4 ++--
fs/ocfs2/journal.c | 33 +++++++++++++++++++++++----------
fs/ocfs2/journal.h | 2 ++
fs/ocfs2/super.c | 15 +++++++++++++++
4 files changed, 42 insertions(+), 12 deletions(-)

diff --git a/fs/ocfs2/inode.c b/fs/ocfs2/inode.c
index 5739dc301569..bb116c39b581 100644
--- a/fs/ocfs2/inode.c
+++ b/fs/ocfs2/inode.c
@@ -125,6 +125,7 @@ struct inode *ocfs2_iget(struct ocfs2_super *osb, u64 blkno, unsigned flags,
struct inode *inode = NULL;
struct super_block *sb = osb->sb;
struct ocfs2_find_inode_args args;
+ journal_t *journal = osb->journal->j_journal;

trace_ocfs2_iget_begin((unsigned long long)blkno, flags,
sysfile_type);
@@ -171,11 +172,10 @@ struct inode *ocfs2_iget(struct ocfs2_super *osb, u64 blkno, unsigned flags,
* part of the transaction - the inode could have been reclaimed and
* now it is reread from disk.
*/
- if (osb->journal) {
+ if (journal) {
transaction_t *transaction;
tid_t tid;
struct ocfs2_inode_info *oi = OCFS2_I(inode);
- journal_t *journal = osb->journal->j_journal;

read_lock(&journal->j_state_lock);
if (journal->j_running_transaction)
diff --git a/fs/ocfs2/journal.c b/fs/ocfs2/journal.c
index 1887a2708709..fa87d89cf754 100644
--- a/fs/ocfs2/journal.c
+++ b/fs/ocfs2/journal.c
@@ -810,22 +810,20 @@ void ocfs2_set_journal_params(struct ocfs2_super *osb)
write_unlock(&journal->j_state_lock);
}

-int ocfs2_journal_init(struct ocfs2_super *osb, int *dirty)
+/*
+ * alloc & initialize skeleton for journal structure.
+ * ocfs2_journal_init() will make fs have journal ability.
+ */
+int ocfs2_journal_alloc(struct ocfs2_super *osb)
{
- int status = -1;
- struct inode *inode = NULL; /* the journal inode */
- journal_t *j_journal = NULL;
- struct ocfs2_journal *journal = NULL;
- struct ocfs2_dinode *di = NULL;
- struct buffer_head *bh = NULL;
- int inode_lock = 0;
+ int status = 0;
+ struct ocfs2_journal *journal;

- /* initialize our journal structure */
journal = kzalloc(sizeof(struct ocfs2_journal), GFP_KERNEL);
if (!journal) {
mlog(ML_ERROR, "unable to alloc journal\n");
status = -ENOMEM;
- goto done;
+ goto bail;
}
osb->journal = journal;
journal->j_osb = osb;
@@ -839,6 +837,21 @@ int ocfs2_journal_init(struct ocfs2_super *osb, int *dirty)
INIT_WORK(&journal->j_recovery_work, ocfs2_complete_recovery);
journal->j_state = OCFS2_JOURNAL_FREE;

+bail:
+ return status;
+}
+
+int ocfs2_journal_init(struct ocfs2_super *osb, int *dirty)
+{
+ int status = -1;
+ struct inode *inode = NULL; /* the journal inode */
+ journal_t *j_journal = NULL;
+ struct ocfs2_journal *journal = osb->journal;
+ struct ocfs2_dinode *di = NULL;
+ struct buffer_head *bh = NULL;
+ int inode_lock = 0;
+
+ BUG_ON(!journal);
/* already have the inode for our journal */
inode = ocfs2_get_system_file_inode(osb, JOURNAL_SYSTEM_INODE,
osb->slot_num);
diff --git a/fs/ocfs2/journal.h b/fs/ocfs2/journal.h
index 8dcb2f2cadbc..969d0aa28718 100644
--- a/fs/ocfs2/journal.h
+++ b/fs/ocfs2/journal.h
@@ -154,6 +154,7 @@ int ocfs2_compute_replay_slots(struct ocfs2_super *osb);
* Journal Control:
* Initialize, Load, Shutdown, Wipe a journal.
*
+ * ocfs2_journal_alloc - Initialize skeleton for journal structure.
* ocfs2_journal_init - Initialize journal structures in the OSB.
* ocfs2_journal_load - Load the given journal off disk. Replay it if
* there's transactions still in there.
@@ -167,6 +168,7 @@ int ocfs2_compute_replay_slots(struct ocfs2_super *osb);
* ocfs2_start_checkpoint - Kick the commit thread to do a checkpoint.
*/
void ocfs2_set_journal_params(struct ocfs2_super *osb);
+int ocfs2_journal_alloc(struct ocfs2_super *osb);
int ocfs2_journal_init(struct ocfs2_super *osb, int *dirty);
void ocfs2_journal_shutdown(struct ocfs2_super *osb);
int ocfs2_journal_wipe(struct ocfs2_journal *journal,
diff --git a/fs/ocfs2/super.c b/fs/ocfs2/super.c
index 477cdf94122e..311433c69a3f 100644
--- a/fs/ocfs2/super.c
+++ b/fs/ocfs2/super.c
@@ -2195,6 +2195,15 @@ static int ocfs2_initialize_super(struct super_block *sb,

get_random_bytes(&osb->s_next_generation, sizeof(u32));

+ /*
+ * FIXME
+ * This should be done in ocfs2_journal_init(), but any inode
+ * writes back operation will cause the filesystem to crash.
+ */
+ status = ocfs2_journal_alloc(osb);
+ if (status < 0)
+ goto bail;
+
INIT_WORK(&osb->dquot_drop_work, ocfs2_drop_dquot_refs);
init_llist_head(&osb->dquot_drop_list);

@@ -2483,6 +2492,12 @@ static void ocfs2_delete_osb(struct ocfs2_super *osb)

kfree(osb->osb_orphan_wipes);
kfree(osb->slot_recovery_generations);
+ /* FIXME
+ * This belongs in journal shutdown, but because we have to
+ * allocate osb->journal at the middle of ocfs2_initialize_super(),
+ * we free it here.
+ */
+ kfree(osb->journal);
kfree(osb->local_alloc_copy);
kfree(osb->uuid_str);
kfree(osb->vol_label);
--
2.35.1