fix-compile-warning-when-using-JBUFFER_TRACE

   1 jbd2: fix compile warning when using JBUFFER_TRACE
   2
   3 From: "zhangyi (F)" <yi.zhang@huawei.com>
   4
   5 The jh pointer may be used uninitialized in the two cases below and the
   6 compiler complain about it when enabling JBUFFER_TRACE macro, fix them.
   7
   8 In file included from fs/jbd2/transaction.c:19:0:
   9 fs/jbd2/transaction.c: In function ‘jbd2_journal_get_undo_access’:
  10 ./include/linux/jbd2.h:1637:38: warning: ‘jh’ is used uninitialized in this function [-Wuninitialized]
  11  #define JBUFFER_TRACE(jh, info) do { printk("%s: %d\n", __func__, jh->b_jcount);} while (0)
  12                                       ^
  13 fs/jbd2/transaction.c:1219:23: note: ‘jh’ was declared here
  14   struct journal_head *jh;
  15                        ^
  16 In file included from fs/jbd2/transaction.c:19:0:
  17 fs/jbd2/transaction.c: In function ‘jbd2_journal_dirty_metadata’:
  18 ./include/linux/jbd2.h:1637:38: warning: ‘jh’ may be used uninitialized in this function [-Wmaybe-uninitialized]
  19  #define JBUFFER_TRACE(jh, info) do { printk("%s: %d\n", __func__, jh->b_jcount);} while (0)
  20                                       ^
  21 fs/jbd2/transaction.c:1332:23: note: ‘jh’ was declared here
  22   struct journal_head *jh;
  23                        ^
  24
  25 Signed-off-by: zhangyi (F) <yi.zhang@huawei.com>
  26 Signed-off-by: Theodore Ts'o <tytso@mit.edu>
  27 Cc: stable@vger.kernel.org
  28 Reviewed-by: Jan Kara <jack@suse.cz>
  29 ---
  30  fs/jbd2/transaction.c | 16 ++++++++--------
  31  1 file changed, 8 insertions(+), 8 deletions(-)
  32
  33 diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c
  34 index c0b66a7..4b51177 100644
  35 --- a/fs/jbd2/transaction.c
  36 +++ b/fs/jbd2/transaction.c
  37 @@ -1219,11 +1219,12 @@ int jbd2_journal_get_undo_access(handle_t *handle, struct buffer_head *bh)
  38         struct journal_head *jh;
  39         char *committed_data = NULL;
  40
  41 -       JBUFFER_TRACE(jh, "entry");
  42         if (jbd2_write_access_granted(handle, bh, true))
  43                 return 0;
  44
  45         jh = jbd2_journal_add_journal_head(bh);
  46 +       JBUFFER_TRACE(jh, "entry");
  47 +
  48         /*
  49          * Do this first --- it can drop the journal lock, so we want to
  50          * make sure that obtaining the committed_data is done
  51 @@ -1334,15 +1335,17 @@ int jbd2_journal_dirty_metadata(handle_t *handle, struct buffer_head *bh)
  52
  53         if (is_handle_aborted(handle))
  54                 return -EROFS;
  55 -       if (!buffer_jbd(bh)) {
  56 -               ret = -EUCLEAN;
  57 -               goto out;
  58 -       }
  59 +       if (!buffer_jbd(bh))
  60 +               return -EUCLEAN;
  61 +
  62         /*
  63          * We don't grab jh reference here since the buffer must be part
  64          * of the running transaction.
  65          */
  66         jh = bh2jh(bh);
  67 +       jbd_debug(5, "journal_head %p\n", jh);
  68 +       JBUFFER_TRACE(jh, "entry");
  69 +
  70         /*
  71          * This and the following assertions are unreliable since we may see jh
  72          * in inconsistent state unless we grab bh_state lock. But this is
  73 @@ -1376,9 +1379,6 @@ int jbd2_journal_dirty_metadata(handle_t *handle, struct buffer_head *bh)
  74         }
  75
  76         journal = transaction->t_journal;
  77 -       jbd_debug(5, "journal_head %p\n", jh);
  78 -       JBUFFER_TRACE(jh, "entry");
  79 -
  80         jbd_lock_bh_state(bh);
  81
  82         if (jh->b_modified == 0) {
  83 --
  84 2.7.4
  85
  86