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Message-ID: <20130624095359.GC20471@quack.suse.cz>
Date: Mon, 24 Jun 2013 11:53:59 +0200
From: Jan Kara <jack@...e.cz>
To: Theodore Ts'o <tytso@....edu>
Cc: Ext4 Developers List <linux-ext4@...r.kernel.org>,
jbacik@...ionio.com, younger.liu@...wei.com,
Jan Kara <jack@...e.cz>
Subject: Re: [PATCH] jbd2: invalidate handle if jbd2_journal_restart() fails
On Sun 23-06-13 13:44:28, Ted Tso wrote:
> If jbd2_journal_restart() fails the handle will have been disconnected
> from the current transaction. In this situation, the handle must not
> be used for for any jbd2 function other than jbd2_journal_stop().
> Enforce this with by treating a handle which has a NULL transaction
> pointer as an aborted handle, and issue a kernel warning if
> jbd2_journal_extent(), jbd2_journal_get_write_access(),
> jbd2_journal_dirty_metadata(), etc. is called with an invalid handle.
>
> This commit also fixes a bug where jbd2_journal_stop() would trip over
> a kernel jbd2 assertion check when trying to free an invalid handle.
>
> Also move the responsibility of setting current->journal_info to
> start_this_handle(), simplifying the three users of this function.
>
> Signed-off-by: "Theodore Ts'o" <tytso@....edu>
> Reported-by: Younger Liu <younger.liu@...wei.com>
> Cc: Jan Kara <jack@...e.cz>
The patch looks good to me. So you can add:
Reviewed-by: Jan Kara <jack@...e.cz>
Honza
> ---
> fs/jbd2/transaction.c | 27 ++++++++++++++++-----------
> include/linux/jbd2.h | 2 +-
> 2 files changed, 17 insertions(+), 12 deletions(-)
>
> diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c
> index 7391456..8ac8306 100644
> --- a/fs/jbd2/transaction.c
> +++ b/fs/jbd2/transaction.c
> @@ -368,6 +368,7 @@ repeat:
> atomic_read(&transaction->t_outstanding_credits),
> jbd2_log_space_left(journal));
> read_unlock(&journal->j_state_lock);
> + current->journal_info = handle;
>
> lock_map_acquire(&handle->h_lockdep_map);
> jbd2_journal_free_transaction(new_transaction);
> @@ -442,14 +443,11 @@ handle_t *jbd2__journal_start(journal_t *journal, int nblocks, int rsv_blocks,
> handle->h_rsv_handle = rsv_handle;
> }
>
> - current->journal_info = handle;
> -
> err = start_this_handle(journal, handle, gfp_mask);
> if (err < 0) {
> if (handle->h_rsv_handle)
> jbd2_free_handle(handle->h_rsv_handle);
> jbd2_free_handle(handle);
> - current->journal_info = NULL;
> return ERR_PTR(err);
> }
> handle->h_type = type;
> @@ -511,16 +509,13 @@ int jbd2_journal_start_reserved(handle_t *handle, unsigned int type,
> }
>
> handle->h_journal = NULL;
> - current->journal_info = handle;
> /*
> * GFP_NOFS is here because callers are likely from writeback or
> * similarly constrained call sites
> */
> ret = start_this_handle(journal, handle, GFP_NOFS);
> - if (ret < 0) {
> - current->journal_info = NULL;
> + if (ret < 0)
> jbd2_journal_free_reserved(handle);
> - }
> handle->h_type = type;
> handle->h_line_no = line_no;
> return ret;
> @@ -555,6 +550,7 @@ int jbd2_journal_extend(handle_t *handle, int nblocks)
> int wanted;
>
> result = -EIO;
> + WARN_ON(!handle->h_transaction);
> if (is_handle_aborted(handle))
> goto out;
>
> @@ -630,6 +626,7 @@ int jbd2__journal_restart(handle_t *handle, int nblocks, gfp_t gfp_mask)
> tid_t tid;
> int need_to_start, ret;
>
> + WARN_ON(!handle->h_transaction);
> /* If we've had an abort of any type, don't even think about
> * actually doing the restart! */
> if (is_handle_aborted(handle))
> @@ -654,6 +651,8 @@ int jbd2__journal_restart(handle_t *handle, int nblocks, gfp_t gfp_mask)
> wake_up(&journal->j_wait_updates);
> tid = transaction->t_tid;
> spin_unlock(&transaction->t_handle_lock);
> + handle->h_transaction = NULL;
> + current->journal_info = NULL;
>
> jbd_debug(2, "restarting handle %p\n", handle);
> need_to_start = !tid_geq(journal->j_commit_request, tid);
> @@ -790,6 +789,7 @@ do_get_write_access(handle_t *handle, struct journal_head *jh,
> int need_copy = 0;
> unsigned long start_lock, time_lock;
>
> + WARN_ON(!handle->h_transaction);
> if (is_handle_aborted(handle))
> return -EROFS;
>
> @@ -1057,6 +1057,7 @@ int jbd2_journal_get_create_access(handle_t *handle, struct buffer_head *bh)
> int err;
>
> jbd_debug(5, "journal_head %p\n", jh);
> + WARN_ON(!handle->h_transaction);
> err = -EROFS;
> if (is_handle_aborted(handle))
> goto out;
> @@ -1269,6 +1270,7 @@ int jbd2_journal_dirty_metadata(handle_t *handle, struct buffer_head *bh)
> struct journal_head *jh;
> int ret = 0;
>
> + WARN_ON(!handle->h_transaction);
> if (is_handle_aborted(handle))
> goto out;
> jh = jbd2_journal_grab_journal_head(bh);
> @@ -1523,18 +1525,19 @@ int jbd2_journal_stop(handle_t *handle)
> {
> transaction_t *transaction = handle->h_transaction;
> journal_t *journal = transaction->t_journal;
> - int err, wait_for_commit = 0;
> + int err = 0, wait_for_commit = 0;
> tid_t tid;
> pid_t pid;
>
> + if (!handle->h_transaction)
> + goto free_and_exit;
> +
> J_ASSERT(journal_current_handle() == handle);
>
> if (is_handle_aborted(handle))
> err = -EIO;
> - else {
> + else
> J_ASSERT(atomic_read(&transaction->t_updates) > 0);
> - err = 0;
> - }
>
> if (--handle->h_ref > 0) {
> jbd_debug(4, "h_ref %d -> %d\n", handle->h_ref + 1,
> @@ -1657,6 +1660,7 @@ int jbd2_journal_stop(handle_t *handle)
>
> if (handle->h_rsv_handle)
> jbd2_journal_free_reserved(handle->h_rsv_handle);
> +free_and_exit:
> jbd2_free_handle(handle);
> return err;
> }
> @@ -2364,6 +2368,7 @@ int jbd2_journal_file_inode(handle_t *handle, struct jbd2_inode *jinode)
> transaction_t *transaction = handle->h_transaction;
> journal_t *journal = transaction->t_journal;
>
> + WARN_ON(!handle->h_transaction);
> if (is_handle_aborted(handle))
> return -EIO;
>
> diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h
> index 5f3c094..1891112 100644
> --- a/include/linux/jbd2.h
> +++ b/include/linux/jbd2.h
> @@ -1295,7 +1295,7 @@ static inline int is_journal_aborted(journal_t *journal)
>
> static inline int is_handle_aborted(handle_t *handle)
> {
> - if (handle->h_aborted)
> + if (handle->h_aborted || !handle->h_transaction)
> return 1;
> return is_journal_aborted(handle->h_transaction->t_journal);
> }
> --
> 1.7.12.rc0.22.gcdd159b
>
--
Jan Kara <jack@...e.cz>
SUSE Labs, CR
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