Jeff Liu
2013-Apr-09 03:17 UTC
[Ocfs2-devel] [PATCH 2/2] ocfs2: Fix NULL dereference for moving extents
From: Dan Carpenter <dan.carpenter at oracle.com> We can't dereference "bg" before it has been assigned. GCC should have warned about this but "bg" was initialized to NULL. I've fixed that as well. Signed-off-by: Dan Carpenter <dan.carpenter at oracle.com> Reviewed-by: Jie Liu <jeff.liu at oracle.com> --- fs/ocfs2/move_extents.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) diff --git a/fs/ocfs2/move_extents.c b/fs/ocfs2/move_extents.c index ce1ce76..0b974b5 100644 --- a/fs/ocfs2/move_extents.c +++ b/fs/ocfs2/move_extents.c @@ -473,7 +473,7 @@ static int ocfs2_validate_and_adjust_move_goal(struct inode *inode, int ret, goal_bit = 0; struct buffer_head *gd_bh = NULL; - struct ocfs2_group_desc *bg = NULL; + struct ocfs2_group_desc *bg; struct ocfs2_super *osb = OCFS2_SB(inode->i_sb); int c_to_b = 1 << (osb->s_clustersize_bits - inode->i_sb->s_blocksize_bits); @@ -484,13 +484,6 @@ static int ocfs2_validate_and_adjust_move_goal(struct inode *inode, range->me_goal = ocfs2_block_to_cluster_start(inode->i_sb, range->me_goal); /* - * moving goal is not allowd to start with a group desc blok(#0 blk) - * let's compromise to the latter cluster. - */ - if (range->me_goal == le64_to_cpu(bg->bg_blkno)) - range->me_goal += c_to_b; - - /* * validate goal sits within global_bitmap, and return the victim * group desc */ @@ -504,6 +497,13 @@ static int ocfs2_validate_and_adjust_move_goal(struct inode *inode, bg = (struct ocfs2_group_desc *)gd_bh->b_data; /* + * moving goal is not allowd to start with a group desc blok(#0 blk) + * let's compromise to the latter cluster. + */ + if (range->me_goal == le64_to_cpu(bg->bg_blkno)) + range->me_goal += c_to_b; + + /* * movement is not gonna cross two groups. */ if ((le16_to_cpu(bg->bg_bits) - goal_bit) * osb->s_clustersize < -- 1.7.9.5