[Ocfs2-devel] [PATCH] ocfs2: fix NULL pointer dereference in ocfs2_duplicate_clusters_by_page
Tao Ma
tm at tao.ma
Fri Sep 28 00:07:40 PDT 2012
Hi Tiger,
Interesting.
why we never find it in the old reflink test? A little big strange.
Could you please tell me the test case to trigger this issue?
Another thing I want to say is that now your patch removes all the
readahead during CoW. Why? If you want to avoid the dereference of a
NULL pointer, I guess just skip the call of ocfs2_readahead_for_cow if
file = NULL should work?
Thanks
Tao
On 09/28/2012 02:57 PM, Tiger Yang wrote:
> Since ocfs2_cow_file_pos will invoke ocfs2_refcount_cow with a NULL
> as the struct file pointer, it finally result in a null pointer
> dereference in ocfs2_duplicate_clusters_by_page.
> This patch replace file pointer with inode pointer in
> cow_duplicate_clusters to fix this issue.
>
> Signed-off-by: Tiger Yang <tiger.yang at oracle.com>
> ---
> fs/ocfs2/aops.c | 2 +-
> fs/ocfs2/file.c | 6 ++--
> fs/ocfs2/move_extents.c | 2 +-
> fs/ocfs2/refcounttree.c | 53 +++++++---------------------------------------
> fs/ocfs2/refcounttree.h | 6 ++--
> 5 files changed, 16 insertions(+), 53 deletions(-)
>
> diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c
> index 6577432..8cc8cad 100644
> --- a/fs/ocfs2/aops.c
> +++ b/fs/ocfs2/aops.c
> @@ -1755,7 +1755,7 @@ try_again:
> goto out;
> } else if (ret == 1) {
> clusters_need = wc->w_clen;
> - ret = ocfs2_refcount_cow(inode, filp, di_bh,
> + ret = ocfs2_refcount_cow(inode, di_bh,
> wc->w_cpos, wc->w_clen, UINT_MAX);
> if (ret) {
> mlog_errno(ret);
> diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c
> index 46a1f6d..e26cd20 100644
> --- a/fs/ocfs2/file.c
> +++ b/fs/ocfs2/file.c
> @@ -370,7 +370,7 @@ static int ocfs2_cow_file_pos(struct inode *inode,
> if (!(ext_flags & OCFS2_EXT_REFCOUNTED))
> goto out;
>
> - return ocfs2_refcount_cow(inode, NULL, fe_bh, cpos, 1, cpos+1);
> + return ocfs2_refcount_cow(inode, fe_bh, cpos, 1, cpos+1);
>
> out:
> return status;
> @@ -899,7 +899,7 @@ static int ocfs2_zero_extend_get_range(struct inode *inode,
> zero_clusters = last_cpos - zero_cpos;
>
> if (needs_cow) {
> - rc = ocfs2_refcount_cow(inode, NULL, di_bh, zero_cpos,
> + rc = ocfs2_refcount_cow(inode, di_bh, zero_cpos,
> zero_clusters, UINT_MAX);
> if (rc) {
> mlog_errno(rc);
> @@ -2097,7 +2097,7 @@ static int ocfs2_prepare_inode_for_refcount(struct inode *inode,
>
> *meta_level = 1;
>
> - ret = ocfs2_refcount_cow(inode, file, di_bh, cpos, clusters, UINT_MAX);
> + ret = ocfs2_refcount_cow(inode, di_bh, cpos, clusters, UINT_MAX);
> if (ret)
> mlog_errno(ret);
> out:
> diff --git a/fs/ocfs2/move_extents.c b/fs/ocfs2/move_extents.c
> index 6083432..8519926 100644
> --- a/fs/ocfs2/move_extents.c
> +++ b/fs/ocfs2/move_extents.c
> @@ -69,7 +69,7 @@ static int __ocfs2_move_extent(handle_t *handle,
> u64 ino = ocfs2_metadata_cache_owner(context->et.et_ci);
> u64 old_blkno = ocfs2_clusters_to_blocks(inode->i_sb, p_cpos);
>
> - ret = ocfs2_duplicate_clusters_by_page(handle, context->file, cpos,
> + ret = ocfs2_duplicate_clusters_by_page(handle, inode, cpos,
> p_cpos, new_p_cpos, len);
> if (ret) {
> mlog_errno(ret);
> diff --git a/fs/ocfs2/refcounttree.c b/fs/ocfs2/refcounttree.c
> index 30a0550..2d1bb91 100644
> --- a/fs/ocfs2/refcounttree.c
> +++ b/fs/ocfs2/refcounttree.c
> @@ -49,7 +49,6 @@
>
> struct ocfs2_cow_context {
> struct inode *inode;
> - struct file *file;
> u32 cow_start;
> u32 cow_len;
> struct ocfs2_extent_tree data_et;
> @@ -66,7 +65,7 @@ struct ocfs2_cow_context {
> u32 *num_clusters,
> unsigned int *extent_flags);
> int (*cow_duplicate_clusters)(handle_t *handle,
> - struct file *file,
> + struct inode *inode,
> u32 cpos, u32 old_cluster,
> u32 new_cluster, u32 new_len);
> };
> @@ -2922,14 +2921,12 @@ static int ocfs2_clear_cow_buffer(handle_t *handle, struct buffer_head *bh)
> }
>
> int ocfs2_duplicate_clusters_by_page(handle_t *handle,
> - struct file *file,
> + struct inode *inode,
> u32 cpos, u32 old_cluster,
> u32 new_cluster, u32 new_len)
> {
> int ret = 0, partial;
> - struct inode *inode = file->f_path.dentry->d_inode;
> - struct ocfs2_caching_info *ci = INODE_CACHE(inode);
> - struct super_block *sb = ocfs2_metadata_cache_get_super(ci);
> + struct super_block *sb = inode->i_sb;
> u64 new_block = ocfs2_clusters_to_blocks(sb, new_cluster);
> struct page *page;
> pgoff_t page_index;
> @@ -2973,13 +2970,6 @@ int ocfs2_duplicate_clusters_by_page(handle_t *handle,
> if (PAGE_CACHE_SIZE <= OCFS2_SB(sb)->s_clustersize)
> BUG_ON(PageDirty(page));
>
> - if (PageReadahead(page)) {
> - page_cache_async_readahead(mapping,
> - &file->f_ra, file,
> - page, page_index,
> - readahead_pages);
> - }
> -
> if (!PageUptodate(page)) {
> ret = block_read_full_page(page, ocfs2_get_block);
> if (ret) {
> @@ -2999,7 +2989,8 @@ int ocfs2_duplicate_clusters_by_page(handle_t *handle,
> }
> }
>
> - ocfs2_map_and_dirty_page(inode, handle, from, to,
> + ocfs2_map_and_dirty_page(inode,
> + handle, from, to,
> page, 0, &new_block);
> mark_page_accessed(page);
> unlock:
> @@ -3015,12 +3006,11 @@ unlock:
> }
>
> int ocfs2_duplicate_clusters_by_jbd(handle_t *handle,
> - struct file *file,
> + struct inode *inode,
> u32 cpos, u32 old_cluster,
> u32 new_cluster, u32 new_len)
> {
> int ret = 0;
> - struct inode *inode = file->f_path.dentry->d_inode;
> struct super_block *sb = inode->i_sb;
> struct ocfs2_caching_info *ci = INODE_CACHE(inode);
> int i, blocks = ocfs2_clusters_to_blocks(sb, new_len);
> @@ -3145,7 +3135,7 @@ static int ocfs2_replace_clusters(handle_t *handle,
>
> /*If the old clusters is unwritten, no need to duplicate. */
> if (!(ext_flags & OCFS2_EXT_UNWRITTEN)) {
> - ret = context->cow_duplicate_clusters(handle, context->file,
> + ret = context->cow_duplicate_clusters(handle, context->inode,
> cpos, old, new, len);
> if (ret) {
> mlog_errno(ret);
> @@ -3423,35 +3413,12 @@ static int ocfs2_replace_cow(struct ocfs2_cow_context *context)
> return ret;
> }
>
> -static void ocfs2_readahead_for_cow(struct inode *inode,
> - struct file *file,
> - u32 start, u32 len)
> -{
> - struct address_space *mapping;
> - pgoff_t index;
> - unsigned long num_pages;
> - int cs_bits = OCFS2_SB(inode->i_sb)->s_clustersize_bits;
> -
> - if (!file)
> - return;
> -
> - mapping = file->f_mapping;
> - num_pages = (len << cs_bits) >> PAGE_CACHE_SHIFT;
> - if (!num_pages)
> - num_pages = 1;
> -
> - index = ((loff_t)start << cs_bits) >> PAGE_CACHE_SHIFT;
> - page_cache_sync_readahead(mapping, &file->f_ra, file,
> - index, num_pages);
> -}
> -
> /*
> * Starting at cpos, try to CoW write_len clusters. Don't CoW
> * past max_cpos. This will stop when it runs into a hole or an
> * unrefcounted extent.
> */
> static int ocfs2_refcount_cow_hunk(struct inode *inode,
> - struct file *file,
> struct buffer_head *di_bh,
> u32 cpos, u32 write_len, u32 max_cpos)
> {
> @@ -3480,8 +3447,6 @@ static int ocfs2_refcount_cow_hunk(struct inode *inode,
>
> BUG_ON(cow_len == 0);
>
> - ocfs2_readahead_for_cow(inode, file, cow_start, cow_len);
> -
> context = kzalloc(sizeof(struct ocfs2_cow_context), GFP_NOFS);
> if (!context) {
> ret = -ENOMEM;
> @@ -3503,7 +3468,6 @@ static int ocfs2_refcount_cow_hunk(struct inode *inode,
> context->ref_root_bh = ref_root_bh;
> context->cow_duplicate_clusters = ocfs2_duplicate_clusters_by_page;
> context->get_clusters = ocfs2_di_get_clusters;
> - context->file = file;
>
> ocfs2_init_dinode_extent_tree(&context->data_et,
> INODE_CACHE(inode), di_bh);
> @@ -3532,7 +3496,6 @@ out:
> * clusters between cpos and cpos+write_len are safe to modify.
> */
> int ocfs2_refcount_cow(struct inode *inode,
> - struct file *file,
> struct buffer_head *di_bh,
> u32 cpos, u32 write_len, u32 max_cpos)
> {
> @@ -3552,7 +3515,7 @@ int ocfs2_refcount_cow(struct inode *inode,
> num_clusters = write_len;
>
> if (ext_flags & OCFS2_EXT_REFCOUNTED) {
> - ret = ocfs2_refcount_cow_hunk(inode, file, di_bh, cpos,
> + ret = ocfs2_refcount_cow_hunk(inode, di_bh, cpos,
> num_clusters, max_cpos);
> if (ret) {
> mlog_errno(ret);
> diff --git a/fs/ocfs2/refcounttree.h b/fs/ocfs2/refcounttree.h
> index 7754608..6422bbc 100644
> --- a/fs/ocfs2/refcounttree.h
> +++ b/fs/ocfs2/refcounttree.h
> @@ -53,7 +53,7 @@ int ocfs2_prepare_refcount_change_for_del(struct inode *inode,
> int *credits,
> int *ref_blocks);
> int ocfs2_refcount_cow(struct inode *inode,
> - struct file *filep, struct buffer_head *di_bh,
> + struct buffer_head *di_bh,
> u32 cpos, u32 write_len, u32 max_cpos);
>
> typedef int (ocfs2_post_refcount_func)(struct inode *inode,
> @@ -85,11 +85,11 @@ int ocfs2_refcount_cow_xattr(struct inode *inode,
> u32 cpos, u32 write_len,
> struct ocfs2_post_refcount *post);
> int ocfs2_duplicate_clusters_by_page(handle_t *handle,
> - struct file *file,
> + struct inode *inode,
> u32 cpos, u32 old_cluster,
> u32 new_cluster, u32 new_len);
> int ocfs2_duplicate_clusters_by_jbd(handle_t *handle,
> - struct file *file,
> + struct inode *inode,
> u32 cpos, u32 old_cluster,
> u32 new_cluster, u32 new_len);
> int ocfs2_cow_sync_writeback(struct super_block *sb,
>
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