[Ocfs2-devel] [PATCH] ocfs2: fix NULL pointer dereference in ocfs2_duplicate_clusters_by_page
Tiger Yang
tiger.yang at oracle.com
Tue Oct 9 23:22:10 PDT 2012
On 09/28/2012 03:07 PM, Tao Ma wrote:
> 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?
just the reflink test in single_run-WIP.sh.
> 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 for review, I made v2 patch which add check of the pointer to fix
this issue.
Thanks,
tiger
> 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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