[PATCH 4.14 136/183] jbd2: fix compile warning when using JBUFFER_TRACE

From: Greg Kroah-Hartman
Date: Fri Mar 22 2019 - 08:51:59 EST


4.14-stable review patch. If anyone has any objections, please let me know.

------------------

From: zhangyi (F) <yi.zhang@xxxxxxxxxx>

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 âjbd2_journal_get_undo_accessâ:
./include/linux/jbd2.h:1637:38: warning: âjhâ 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: âjhâ was declared here
struct journal_head *jh;
^
In file included from fs/jbd2/transaction.c:19:0:
fs/jbd2/transaction.c: In function âjbd2_journal_dirty_metadataâ:
./include/linux/jbd2.h:1637:38: warning: âjhâ 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: âjhâ was declared here
struct journal_head *jh;
^

Signed-off-by: zhangyi (F) <yi.zhang@xxxxxxxxxx>
Signed-off-by: Theodore Ts'o <tytso@xxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Reviewed-by: Jan Kara <jack@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
fs/jbd2/transaction.c | 16 ++++++++--------
1 file changed, 8 insertions(+), 8 deletions(-)

--- a/fs/jbd2/transaction.c
+++ b/fs/jbd2/transaction.c
@@ -1224,11 +1224,12 @@ int jbd2_journal_get_undo_access(handle_
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
@@ -1339,15 +1340,17 @@ int jbd2_journal_dirty_metadata(handle_t

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
@@ -1381,9 +1384,6 @@ int jbd2_journal_dirty_metadata(handle_t
}

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) {