+ pagevec_init(&pvec, 0);
+ if (wbc->sync_mode == WB_SYNC_NONE)
+ index = mapping->writeback_index; /* Start from prev offset */
+ else {
+ index = 0;
+ scanned = 1;
+ }
+ if (wbc->start || wbc->end) {
+ index = wbc->start >> PAGE_CACHE_SHIFT;
+ end = wbc->end >> PAGE_CACHE_SHIFT;
+ is_range = 1;
+ scanned = 1;
+ }
+retry:
+ while (!done && (index <= end) &&
+ (nr_pages = pagevec_lookup_tag(&pvec, mapping, &index,
+ PAGECACHE_TAG_DIRTY,
+ min(end - index, (pgoff_t)PAGEVEC_SIZE - 1) + 1))) {
+ int first;
+ unsigned int i;
+
+ first = -1;
+ next = 0;
+ n_iov = 0;
+ bytes_to_write = 0;
+
+ for (i = 0; i < nr_pages; i++) {
+ page = pvec.pages[i];
+ /*
+ * At this point we hold neither mapping->tree_lock nor
+ * lock on the page itself: the page may be truncated or
+ * invalidated (changing page->mapping to NULL), or even
+ * swizzled back from swapper_space to tmpfs file
+ * mapping
+ */
+
+ if (first < 0)
+ lock_page(page);
+ else if (TestSetPageLocked(page))
+ break;
+
+ if (unlikely(page->mapping != mapping)) {
+ unlock_page(page);
+ break;
+ }
+
+ if (unlikely(is_range) && (page->index > end)) {
+ done = 1;
+ unlock_page(page);
+ break;
+ }
+
+ if (next && (page->index != next)) {
+ /* Not next consecutive page */
+ unlock_page(page);
+ break;
+ }
+
+ if (wbc->sync_mode != WB_SYNC_NONE)
+ wait_on_page_writeback(page);
+
+ if (PageWriteback(page) ||
+ !test_clear_page_dirty(page)) {
+ unlock_page(page);
+ break;
+ }
+
+ if (page_offset(page) >= mapping->host->i_size) {
+ done = 1;
+ unlock_page(page);
+ break;
+ }
+
+ /*
+ * BB can we get rid of this? pages are held by pvec
+ */
+ page_cache_get(page);
+
+ len = min(mapping->host->i_size - page_offset(page),
+ (loff_t)PAGE_CACHE_SIZE);
+
+ /* reserve iov[0] for the smb header */
+ n_iov++;
+ iov[n_iov].iov_base = kmap(page);
+ iov[n_iov].iov_len = len;
+ bytes_to_write += len;
+
+ if (first < 0) {
+ first = i;
+ offset = page_offset(page);
+ }
+ next = page->index + 1;
+ if (bytes_to_write + PAGE_CACHE_SIZE > cifs_sb->wsize)
+ break;
+ }
+ if (n_iov) {
+ /* Search for a writable handle every time we call
+ * CIFSSMBWrite2. We can't rely on the last handle
+ * we used to still be valid
+ */
+ open_file = find_writable_file(CIFS_I(mapping->host));
+ if (!open_file) {
+ cERROR(1, ("No writable handles for inode"));
+ rc = -EBADF;
+ } else {
+ rc = CIFSSMBWrite2(xid, cifs_sb->tcon,
+ open_file->netfid,
+ bytes_to_write, offset,
+ &bytes_written, iov, n_iov,
+ 1);
+ atomic_dec(&open_file->wrtPending);
+ if (rc || bytes_written < bytes_to_write) {
+ cERROR(1,("Write2 ret %d, written = %d",
+ rc, bytes_written));
+ /* BB what if continued retry is
+ requested via mount flags? */
+ set_bit(AS_EIO, &mapping->flags);
+ } else {
+ cifs_stats_bytes_written(cifs_sb->tcon,
+ bytes_written);
+ }
+ }
+ for (i = 0; i < n_iov; i++) {
+ page = pvec.pages[first + i];
+ /* Should we also set page error on
+ success rc but too little data written? */
+ /* BB investigate retry logic on temporary
+ server crash cases and how recovery works
+ when page marked as error */
+ if(rc)
+ SetPageError(page);
+ kunmap(page);
+ unlock_page(page);
+ page_cache_release(page);
+ }
+ if ((wbc->nr_to_write -= n_iov) <= 0)
+ done = 1;
+ index = next;
+ }
+ pagevec_release(&pvec);
+ }
+ if (!scanned && !done) {
+ /*
+ * We hit the last page and there is more work to be done: wrap
+ * back to the start of the file
+ */
+ scanned = 1;
+ index = 0;
+ goto retry;
+ }
+ if (!is_range)
+ mapping->writeback_index = index;
+