[Ocfs2-devel] [PATCH v3 1/5] ocfs2: fix mounting crash if journal is not alloced
Joseph Qi
joseph.qi at linux.alibaba.com
Thu Apr 28 11:28:13 UTC 2022
On 4/24/22 9:09 PM, Heming Zhao wrote:
> 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.
>
> Fixes: da5e7c87827e8 ("ocfs2: cleanup journal init and shutdown")
> Signed-off-by: Heming Zhao <heming.zhao at suse.com>
Reviewed-by: Joseph Qi <joseph.qi at linux.alibaba.com>
> ---
> 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);
More information about the Ocfs2-devel
mailing list