From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tiger Yang Date: Wed, 10 Oct 2012 14:22:10 +0800 Subject: [Ocfs2-devel] [PATCH] ocfs2: fix NULL pointer dereference in ocfs2_duplicate_clusters_by_page In-Reply-To: <50654CBC.3020406@tao.ma> References: <1348815422-1868-1-git-send-email-tiger.yang@oracle.com> <50654CBC.3020406@tao.ma> Message-ID: <50751412.3010908@oracle.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: ocfs2-devel@oss.oracle.com 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 >> --- >> 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, >>