jbd2: fix compile warning when using JBUFFER_TRACE

commit 01215d3edb0f384ddeaa5e4a22c1ae5ff634149f upstream.

The jh pointer may be used uninitialized in the two cases below and the
compiler complain about it when enabling JBUFFER_TRACE macro, fix them.

In file included from fs/jbd2/transaction.c:19:0:
fs/jbd2/transaction.c: In function ‘jbd2_journal_get_undo_access’:
./include/linux/jbd2.h:1637:38: warning: ‘jh’ is used uninitialized in this function [-Wuninitialized]
 #define JBUFFER_TRACE(jh, info) do { printk("%s: %d\n", __func__, jh->b_jcount);} while (0)
                                      ^
fs/jbd2/transaction.c:1219:23: note: ‘jh’ was declared here
  struct journal_head *jh;
                       ^
In file included from fs/jbd2/transaction.c:19:0:
fs/jbd2/transaction.c: In function ‘jbd2_journal_dirty_metadata’:
./include/linux/jbd2.h:1637:38: warning: ‘jh’ may be used uninitialized in this function [-Wmaybe-uninitialized]
 #define JBUFFER_TRACE(jh, info) do { printk("%s: %d\n", __func__, jh->b_jcount);} while (0)
                                      ^
fs/jbd2/transaction.c:1332:23: note: ‘jh’ was declared here
  struct journal_head *jh;
                       ^

Signed-off-by: zhangyi (F) <yi.zhang@huawei.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c
index c15b185..c344334 100644 (file)
--- a/fs/jbd2/transaction.c
+++ b/fs/jbd2/transaction.c
@@ -1215,11 +1215,12 @@ int jbd2_journal_get_undo_access(handle_t *handle, struct buffer_head *bh)
        struct journal_head *jh;
        char *committed_data = NULL;
 
-       JBUFFER_TRACE(jh, "entry");
        if (jbd2_write_access_granted(handle, bh, true))
                return 0;
 
        jh = jbd2_journal_add_journal_head(bh);
+       JBUFFER_TRACE(jh, "entry");
+
        /*
         * Do this first --- it can drop the journal lock, so we want to
         * make sure that obtaining the committed_data is done
@@ -1336,15 +1337,17 @@ int jbd2_journal_dirty_metadata(handle_t *handle, struct buffer_head *bh)
 
        if (is_handle_aborted(handle))
                return -EROFS;
-       if (!buffer_jbd(bh)) {
-               ret = -EUCLEAN;
-               goto out;
-       }
+       if (!buffer_jbd(bh))
+               return -EUCLEAN;
+
        /*
         * We don't grab jh reference here since the buffer must be part
         * of the running transaction.
         */
        jh = bh2jh(bh);
+       jbd_debug(5, "journal_head %p\n", jh);
+       JBUFFER_TRACE(jh, "entry");
+
        /*
         * This and the following assertions are unreliable since we may see jh
         * in inconsistent state unless we grab bh_state lock. But this is
@@ -1378,9 +1381,6 @@ int jbd2_journal_dirty_metadata(handle_t *handle, struct buffer_head *bh)
        }
 
        journal = transaction->t_journal;
-       jbd_debug(5, "journal_head %p\n", jh);
-       JBUFFER_TRACE(jh, "entry");
-
        jbd_lock_bh_state(bh);
 
        if (jh->b_modified == 0) {