On Fri, 7 Sep 2018 15:25:01 +0300 Dan Carpenter <dan.carpenter@xxxxxxxxxx> wrote:
> I started looking at this code because of a Smatch false positive:
>
> fs/ocfs2/move_extents.c:347 ocfs2_defrag_extent()
> warn: variable dereferenced before check 'context->data_ac' (see line 304)
>
> context->data_ac can't be NULL so I removed the check. I changed the
> next lines to use "data_ac" instead of "context->data_ac" for
> consistency. And we don't need to pass "data_ac" to
> ocfs2_lock_meta_allocator_move_extents() any more so I removed that.
>
> Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
>
Please don't forget the ^---$ at end-of-changelog.
> --- a/fs/ocfs2/move_extents.c
> +++ b/fs/ocfs2/move_extents.c
> @@ -160,15 +160,12 @@ static int __ocfs2_move_extent(handle_t *handle,
> * lock allocators, and reserving appropriate number of bits for
> * meta blocks and data clusters.
> *
> - * in some cases, we don't need to reserve clusters, just let data_ac
> - * be NULL.
> */
> static int ocfs2_lock_meta_allocator_move_extents(struct inode *inode,
> struct ocfs2_extent_tree *et,
> u32 clusters_to_move,
> u32 extents_to_split,
> struct ocfs2_alloc_context **meta_ac,
> - struct ocfs2_alloc_context **data_ac,
> int extra_blocks,
> int *credits)
> {
> @@ -255,7 +252,6 @@ static int ocfs2_defrag_extent(struct ocfs2_move_extents_context *context,
> ret = ocfs2_lock_meta_allocator_move_extents(inode, &context->et,
> *len, 1,
> &context->meta_ac,
> - &context->data_ac,
> extra_blocks, &credits);
> if (ret) {
> mlog_errno(ret);
> @@ -344,10 +340,10 @@ static int ocfs2_defrag_extent(struct ocfs2_move_extents_context *context,
> mlog_errno(ret);
>
> out_commit:
> - if (need_free && context->data_ac) {
> + if (need_free) {
Current mainline is different here.
> struct ocfs2_alloc_context *data_ac = context->data_ac;
>
> - if (context->data_ac->ac_which == OCFS2_AC_USE_LOCAL)
> + if (data_ac->ac_which == OCFS2_AC_USE_LOCAL)
> ocfs2_free_local_alloc_bits(osb, handle, data_ac,
> new_phys_cpos, new_len);
> else
> @@ -629,7 +625,7 @@ static int ocfs2_move_extent(struct ocfs2_move_extents_context *context,
> ret = ocfs2_lock_meta_allocator_move_extents(inode, &context->et,
> len, 1,
> &context->meta_ac,
> - NULL, extra_blocks, &credits);
> + extra_blocks, &credits);
> if (ret) {
> mlog_errno(ret);
> goto out;
