move-lockdep-tracking-to-journal_s

   1 jbd2: move lockdep tracking to journal_s
   2
   3 From: Jan Kara <jack@suse.cz>
   4
   5 Currently lockdep map is tracked in each journal handle. To be able to
   6 expand lockdep support to cover also other cases where we depend on
   7 transaction commit and where handle is not available, move lockdep map
   8 into struct journal_s. Since this makes the lockdep map shared for all
   9 handles, we have to use rwsem_acquire_read() for acquisitions now.
  10
  11 Signed-off-by: Jan Kara <jack@suse.cz>
  12 Signed-off-by: Theodore Ts'o <tytso@mit.edu>
  13 ---
  14  fs/jbd2/journal.c     |  4 ++++
  15  fs/jbd2/transaction.c | 11 +++--------
  16  include/linux/jbd2.h  | 17 +++++++++++++----
  17  3 files changed, 20 insertions(+), 12 deletions(-)
  18
  19 diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
  20 index b31852f..208e405 100644
  21 --- a/fs/jbd2/journal.c
  22 +++ b/fs/jbd2/journal.c
  23 @@ -1091,6 +1091,7 @@ static void jbd2_stats_proc_exit(journal_t *journal)
  24
  25  static journal_t * journal_init_common (void)
  26  {
  27 +       static struct lock_class_key jbd2_trans_commit_key;
  28         journal_t *journal;
  29         int err;
  30
  31 @@ -1126,6 +1127,9 @@ static journal_t * journal_init_common (void)
  32
  33         spin_lock_init(&journal->j_history_lock);
  34
  35 +       lockdep_init_map(&journal->j_trans_commit_map, "jbd2_handle",
  36 +                        &jbd2_trans_commit_key, 0);
  37 +
  38         return journal;
  39  }
  40
  41 diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c
  42 index 4124953..c006504 100644
  43 --- a/fs/jbd2/transaction.c
  44 +++ b/fs/jbd2/transaction.c
  45 @@ -382,13 +382,11 @@ repeat:
  46         read_unlock(&journal->j_state_lock);
  47         current->journal_info = handle;
  48
  49 -       lock_map_acquire(&handle->h_lockdep_map);
  50 +       rwsem_acquire_read(&journal->j_trans_commit_map, 0, 0, _THIS_IP_);
  51         jbd2_journal_free_transaction(new_transaction);
  52         return 0;
  53  }
  54
  55 -static struct lock_class_key jbd2_handle_key;
  56 -
  57  /* Allocate a new handle.  This should probably be in a slab... */
  58  static handle_t *new_handle(int nblocks)
  59  {
  60 @@ -398,9 +396,6 @@ static handle_t *new_handle(int nblocks)
  61         handle->h_buffer_credits = nblocks;
  62         handle->h_ref = 1;
  63
  64 -       lockdep_init_map(&handle->h_lockdep_map, "jbd2_handle",
  65 -                                               &jbd2_handle_key, 0);
  66 -
  67         return handle;
  68  }
  69
  70 @@ -672,7 +667,7 @@ int jbd2__journal_restart(handle_t *handle, int nblocks, gfp_t gfp_mask)
  71         if (need_to_start)
  72                 jbd2_log_start_commit(journal, tid);
  73
  74 -       lock_map_release(&handle->h_lockdep_map);
  75 +       rwsem_release(&journal->j_trans_commit_map, 1, _THIS_IP_);
  76         handle->h_buffer_credits = nblocks;
  77         ret = start_this_handle(journal, handle, gfp_mask);
  78         return ret;
  79 @@ -1750,7 +1745,7 @@ int jbd2_journal_stop(handle_t *handle)
  80                         wake_up(&journal->j_wait_transaction_locked);
  81         }
  82
  83 -       lock_map_release(&handle->h_lockdep_map);
  84 +       rwsem_release(&journal->j_trans_commit_map, 1, _THIS_IP_);
  85
  86         if (wait_for_commit)
  87                 err = jbd2_log_wait_commit(journal, tid);
  88 diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h
  89 index efb232c..3d210cb 100644
  90 --- a/include/linux/jbd2.h
  91 +++ b/include/linux/jbd2.h
  92 @@ -491,10 +491,6 @@ struct jbd2_journal_handle
  93
  94         unsigned long           h_start_jiffies;
  95         unsigned int            h_requested_credits;
  96 -
  97 -#ifdef CONFIG_DEBUG_LOCK_ALLOC
  98 -       struct lockdep_map      h_lockdep_map;
  99 -#endif
 100  };
 101
 102
 103 @@ -793,6 +789,7 @@ jbd2_time_diff(unsigned long start, unsigned long end)
 104   * @j_proc_entry: procfs entry for the jbd statistics directory
 105   * @j_stats: Overall statistics
 106   * @j_private: An opaque pointer to fs-private information.
 107 + * @j_trans_commit_map: Lockdep entity to track transaction commit dependencies
 108   */
 109
 110  struct journal_s
 111 @@ -1035,6 +1032,18 @@ struct journal_s
 112
 113         /* Precomputed journal UUID checksum for seeding other checksums */
 114         __u32 j_csum_seed;
 115 +
 116 +#ifdef CONFIG_DEBUG_LOCK_ALLOC
 117 +       /*
 118 +        * Lockdep entity to track transaction commit dependencies. Handles
 119 +        * hold this "lock" for read, when we wait for commit, we acquire the
 120 +        * "lock" for writing. This matches the properties of jbd2 journalling
 121 +        * where the running transaction has to wait for all handles to be
 122 +        * dropped to commit that transaction and also acquiring a handle may
 123 +        * require transaction commit to finish.
 124 +        */
 125 +       struct lockdep_map      j_trans_commit_map;
 126 +#endif
 127  };
 128
 129  /* journal feature predicate functions */