-static inline void
-ocfs2_set_next_iovec(const struct iovec **iovp, size_t *basep, size_t bytes)
-{
- const struct iovec *iov = *iovp;
- size_t base = *basep;
-
- do {
- int copy = min(bytes, iov->iov_len - base);
-
- bytes -= copy;
- base += copy;
- if (iov->iov_len == base) {
- iov++;
- base = 0;
- }
- } while (bytes);
- *iovp = iov;
- *basep = base;
-}
-
-static struct page * ocfs2_get_write_source(char **ret_src_buf,
- const struct iovec *cur_iov,
- size_t iov_offset)
-{
- int ret;
- char *buf = cur_iov->iov_base + iov_offset;
- struct page *src_page = NULL;
- unsigned long off;
-
- off = (unsigned long)(buf) & ~PAGE_CACHE_MASK;
-
- if (!segment_eq(get_fs(), KERNEL_DS)) {
- /*
- * Pull in the user page. We want to do this outside
- * of the meta data locks in order to preserve locking
- * order in case of page fault.
- */
- ret = get_user_pages(current, current->mm,
- (unsigned long)buf & PAGE_CACHE_MASK, 1,
- 0, 0, &src_page, NULL);
- if (ret == 1)
- *ret_src_buf = kmap(src_page) + off;
- else
- src_page = ERR_PTR(-EFAULT);
- } else {
- *ret_src_buf = buf;
- }
-
- return src_page;
-}
-
-static void ocfs2_put_write_source(struct page *page)
-{
- if (page) {
- kunmap(page);
- page_cache_release(page);
- }
-}
-
-static ssize_t ocfs2_file_buffered_write(struct file *file, loff_t *ppos,
- const struct iovec *iov,
- unsigned long nr_segs,
- size_t count,
- ssize_t o_direct_written)
-{
- int ret = 0;
- ssize_t copied, total = 0;
- size_t iov_offset = 0, bytes;
- loff_t pos;
- const struct iovec *cur_iov = iov;
- struct page *user_page, *page;
- char * uninitialized_var(buf);
- char *dst;
- void *fsdata;
-
- /*
- * handle partial DIO write. Adjust cur_iov if needed.
- */
- ocfs2_set_next_iovec(&cur_iov, &iov_offset, o_direct_written);
-
- do {
- pos = *ppos;
-
- user_page = ocfs2_get_write_source(&buf, cur_iov, iov_offset);
- if (IS_ERR(user_page)) {
- ret = PTR_ERR(user_page);
- goto out;
- }
-
- /* Stay within our page boundaries */
- bytes = min((PAGE_CACHE_SIZE - ((unsigned long)pos & ~PAGE_CACHE_MASK)),
- (PAGE_CACHE_SIZE - ((unsigned long)buf & ~PAGE_CACHE_MASK)));
- /* Stay within the vector boundary */
- bytes = min_t(size_t, bytes, cur_iov->iov_len - iov_offset);
- /* Stay within count */
- bytes = min(bytes, count);
-
- page = NULL;
- ret = ocfs2_write_begin(file, file->f_mapping, pos, bytes, 0,
- &page, &fsdata);
- if (ret) {
- mlog_errno(ret);
- goto out;
- }
-
- dst = kmap_atomic(page, KM_USER0);
- memcpy(dst + (pos & (loff_t)(PAGE_CACHE_SIZE - 1)), buf, bytes);
- kunmap_atomic(dst, KM_USER0);
- flush_dcache_page(page);
- ocfs2_put_write_source(user_page);
-
- copied = ocfs2_write_end(file, file->f_mapping, pos, bytes,
- bytes, page, fsdata);
- if (copied < 0) {
- mlog_errno(copied);
- ret = copied;
- goto out;
- }
-
- total += copied;
- *ppos = pos + copied;
- count -= copied;
-
- ocfs2_set_next_iovec(&cur_iov, &iov_offset, copied);
- } while(count);
-
-out:
- return total ? total : ret;
-}
-