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


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