ocfs2: Pin journal head before accessing jh->b_committed_data

This patch adds jbd_lock_bh_state() and jbd_unlock_bh_state() around accessses
to jh->b_committed_data.

Fixes oss bugzilla#1131
http://oss.oracle.com/bugzilla/show_bug.cgi?id=1131

Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com>
Signed-off-by: Joel Becker <joel.becker@oracle.com>

1 files changed, 24 insertions, 4 deletions

diff --git a/fs/ocfs2/suballoc.c b/fs/ocfs2/suballoc.c
index 8439f6b324b9..73a16d4666dc 100644
--- a/fs/ocfs2/suballoc.c
+++ b/fs/ocfs2/suballoc.c
@@ -923,14 +923,23 @@ static int ocfs2_test_bg_bit_allocatable(struct buffer_head *bg_bh,
                                          int nr)
 {
         struct ocfs2_group_desc *bg = (struct ocfs2_group_desc *) bg_bh->b_data;
+        int ret;
 
         if (ocfs2_test_bit(nr, (unsigned long *)bg->bg_bitmap))
                 return 0;
-        if (!buffer_jbd(bg_bh) || !bh2jh(bg_bh)->b_committed_data)
+
+        if (!buffer_jbd(bg_bh))
                 return 1;
 
+        jbd_lock_bh_state(bg_bh);
         bg = (struct ocfs2_group_desc *) bh2jh(bg_bh)->b_committed_data;
-        return !ocfs2_test_bit(nr, (unsigned long *)bg->bg_bitmap);
+        if (bg)
+                ret = !ocfs2_test_bit(nr, (unsigned long *)bg->bg_bitmap);
+        else
+                ret = 1;
+        jbd_unlock_bh_state(bg_bh);
+
+        return ret;
 }
 
 static int ocfs2_block_group_find_clear_bits(struct ocfs2_super *osb,
@@ -1885,6 +1894,7 @@ static inline int ocfs2_block_group_clear_bits(handle_t *handle,
         unsigned int tmp;
         int journal_type = OCFS2_JOURNAL_ACCESS_WRITE;
         struct ocfs2_group_desc *undo_bg = NULL;
+        int cluster_bitmap = 0;
 
         mlog_entry_void();
 
@@ -1905,18 +1915,28 @@ static inline int ocfs2_block_group_clear_bits(handle_t *handle,
         }
 
         if (ocfs2_is_cluster_bitmap(alloc_inode))
-                undo_bg = (struct ocfs2_group_desc *) bh2jh(group_bh)->b_committed_data;
+                cluster_bitmap = 1;
+
+        if (cluster_bitmap) {
+                jbd_lock_bh_state(group_bh);
+                undo_bg = (struct ocfs2_group_desc *)
+                                        bh2jh(group_bh)->b_committed_data;
+                BUG_ON(!undo_bg);
+        }
 
         tmp = num_bits;
         while(tmp--) {
                 ocfs2_clear_bit((bit_off + tmp),
                                 (unsigned long *) bg->bg_bitmap);
-                if (ocfs2_is_cluster_bitmap(alloc_inode))
+                if (cluster_bitmap)
                         ocfs2_set_bit(bit_off + tmp,
                                       (unsigned long *) undo_bg->bg_bitmap);
         }
         le16_add_cpu(&bg->bg_free_bits_count, num_bits);
 
+        if (cluster_bitmap)
+                jbd_unlock_bh_state(group_bh);
+
         status = ocfs2_journal_dirty(handle, group_bh);
         if (status < 0)
                 mlog_errno(status);