jbd-stats-through-procfs_fix.patch

   1 From: Mingming Cao <cmm@us.ibm.com>
   2
   3
   4 On Tue, 2007-07-10 at 21:42 -0700, Andrew Morton wrote:
   5 On Tue, 10 Jul 2007 23:21:49 -0400 "Cédric Augonnet" <cedric.augonnet@gmail.com> wrote:
   6 >
   7 > > 2007/7/10, Andrew Morton <akpm@linux-foundation.org>:
   8 > >
   9 > > Hi all,
  10 > >
  11 > > > > +     size = sizeof(struct transaction_stats_s);
  12 > > > > +     s->stats = kmalloc(size, GFP_KERNEL);
  13 > > > > +     if (s == NULL) {
  14 > > > > +             kfree(s);
  15 > > > > +             return -EIO;
  16 > > >
  17 > > > ENOMEM
  18 > >
  19 > > I'm sorry if i missed some point, but i just don't see the use of such
  20 > > a kfree here, not sure Andrew meant you should only return ENOMEM
  21 > > instead, but why issuing those kfree(NULL), instead of just a if (!s)
  22 > > return ENOMEM ?
  23 > >
  24 >
  25 > You found a bug.  It was meant to be
  26 >
  27 >       if (s->stats == NULL)
  28 >
  29
  30 Signed-off-by: Mingming Cao <cmm@us.ibm.com>
  31 ---
  32
  33  fs/jbd2/journal.c    |    2 +-
  34  include/linux/jbd2.h |    3 +++
  35  2 files changed, 4 insertions(+), 1 deletion(-)
  36
  37
  38 Index: linux-2.6.23-rc6/fs/jbd2/journal.c
  39 ===================================================================
  40 --- linux-2.6.23-rc6.orig/fs/jbd2/journal.c     2007-09-20 17:26:01.000000000 -0700
  41 +++ linux-2.6.23-rc6/fs/jbd2/journal.c  2007-09-20 17:26:02.000000000 -0700
  42 @@ -751,7 +751,7 @@ static int jbd2_seq_history_open(struct
  43                 return -EIO;
  44         size = sizeof(struct transaction_stats_s) * journal->j_history_max;
  45         s->stats = kmalloc(size, GFP_KERNEL);
  46 -       if (s == NULL) {
  47 +       if (s->stats == NULL) {
  48                 kfree(s);
  49                 return -EIO;
  50         }
  51 Index: linux-2.6.23-rc6/include/linux/jbd2.h
  52 ===================================================================
  53 --- linux-2.6.23-rc6.orig/include/linux/jbd2.h  2007-09-20 17:26:01.000000000 -0700
  54 +++ linux-2.6.23-rc6/include/linux/jbd2.h       2007-09-20 17:26:02.000000000 -0700
  55 @@ -941,6 +941,9 @@ struct journal_s
  56         struct transaction_stats_s *j_history;
  57         int                     j_history_max;
  58         int                     j_history_cur;
  59 +       /*
  60 +        * Protect the transactions statistics history
  61 +        */
  62         spinlock_t              j_history_lock;
  63         struct proc_dir_entry   *j_proc_entry;
  64         struct transaction_stats_s j_stats;