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-rw-r--r--fs/fuse/file.c194
1 files changed, 193 insertions, 1 deletions
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index f0f0f278b4ea..c5b5982bf386 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -677,6 +677,198 @@ static int fuse_write_end(struct file *file, struct address_space *mapping,
677 return res; 677 return res;
678} 678}
679 679
680static size_t fuse_send_write_pages(struct fuse_req *req, struct file *file,
681 struct inode *inode, loff_t pos,
682 size_t count)
683{
684 size_t res;
685 unsigned offset;
686 unsigned i;
687
688 for (i = 0; i < req->num_pages; i++)
689 fuse_wait_on_page_writeback(inode, req->pages[i]->index);
690
691 res = fuse_send_write(req, file, inode, pos, count, NULL);
692
693 offset = req->page_offset;
694 count = res;
695 for (i = 0; i < req->num_pages; i++) {
696 struct page *page = req->pages[i];
697
698 if (!req->out.h.error && !offset && count >= PAGE_CACHE_SIZE)
699 SetPageUptodate(page);
700
701 if (count > PAGE_CACHE_SIZE - offset)
702 count -= PAGE_CACHE_SIZE - offset;
703 else
704 count = 0;
705 offset = 0;
706
707 unlock_page(page);
708 page_cache_release(page);
709 }
710
711 return res;
712}
713
714static ssize_t fuse_fill_write_pages(struct fuse_req *req,
715 struct address_space *mapping,
716 struct iov_iter *ii, loff_t pos)
717{
718 struct fuse_conn *fc = get_fuse_conn(mapping->host);
719 unsigned offset = pos & (PAGE_CACHE_SIZE - 1);
720 size_t count = 0;
721 int err;
722
723 req->page_offset = offset;
724
725 do {
726 size_t tmp;
727 struct page *page;
728 pgoff_t index = pos >> PAGE_CACHE_SHIFT;
729 size_t bytes = min_t(size_t, PAGE_CACHE_SIZE - offset,
730 iov_iter_count(ii));
731
732 bytes = min_t(size_t, bytes, fc->max_write - count);
733
734 again:
735 err = -EFAULT;
736 if (iov_iter_fault_in_readable(ii, bytes))
737 break;
738
739 err = -ENOMEM;
740 page = __grab_cache_page(mapping, index);
741 if (!page)
742 break;
743
744 pagefault_disable();
745 tmp = iov_iter_copy_from_user_atomic(page, ii, offset, bytes);
746 pagefault_enable();
747 flush_dcache_page(page);
748
749 if (!tmp) {
750 unlock_page(page);
751 page_cache_release(page);
752 bytes = min(bytes, iov_iter_single_seg_count(ii));
753 goto again;
754 }
755
756 err = 0;
757 req->pages[req->num_pages] = page;
758 req->num_pages++;
759
760 iov_iter_advance(ii, tmp);
761 count += tmp;
762 pos += tmp;
763 offset += tmp;
764 if (offset == PAGE_CACHE_SIZE)
765 offset = 0;
766
767 } while (iov_iter_count(ii) && count < fc->max_write &&
768 req->num_pages < FUSE_MAX_PAGES_PER_REQ && offset == 0);
769
770 return count > 0 ? count : err;
771}
772
773static ssize_t fuse_perform_write(struct file *file,
774 struct address_space *mapping,
775 struct iov_iter *ii, loff_t pos)
776{
777 struct inode *inode = mapping->host;
778 struct fuse_conn *fc = get_fuse_conn(inode);
779 int err = 0;
780 ssize_t res = 0;
781
782 if (is_bad_inode(inode))
783 return -EIO;
784
785 do {
786 struct fuse_req *req;
787 ssize_t count;
788
789 req = fuse_get_req(fc);
790 if (IS_ERR(req)) {
791 err = PTR_ERR(req);
792 break;
793 }
794
795 count = fuse_fill_write_pages(req, mapping, ii, pos);
796 if (count <= 0) {
797 err = count;
798 } else {
799 size_t num_written;
800
801 num_written = fuse_send_write_pages(req, file, inode,
802 pos, count);
803 err = req->out.h.error;
804 if (!err) {
805 res += num_written;
806 pos += num_written;
807
808 /* break out of the loop on short write */
809 if (num_written != count)
810 err = -EIO;
811 }
812 }
813 fuse_put_request(fc, req);
814 } while (!err && iov_iter_count(ii));
815
816 if (res > 0)
817 fuse_write_update_size(inode, pos);
818
819 fuse_invalidate_attr(inode);
820
821 return res > 0 ? res : err;
822}
823
824static ssize_t fuse_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
825 unsigned long nr_segs, loff_t pos)
826{
827 struct file *file = iocb->ki_filp;
828 struct address_space *mapping = file->f_mapping;
829 size_t count = 0;
830 ssize_t written = 0;
831 struct inode *inode = mapping->host;
832 ssize_t err;
833 struct iov_iter i;
834
835 WARN_ON(iocb->ki_pos != pos);
836
837 err = generic_segment_checks(iov, &nr_segs, &count, VERIFY_READ);
838 if (err)
839 return err;
840
841 mutex_lock(&inode->i_mutex);
842 vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);
843
844 /* We can write back this queue in page reclaim */
845 current->backing_dev_info = mapping->backing_dev_info;
846
847 err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
848 if (err)
849 goto out;
850
851 if (count == 0)
852 goto out;
853
854 err = remove_suid(file->f_path.dentry);
855 if (err)
856 goto out;
857
858 file_update_time(file);
859
860 iov_iter_init(&i, iov, nr_segs, count, 0);
861 written = fuse_perform_write(file, mapping, &i, pos);
862 if (written >= 0)
863 iocb->ki_pos = pos + written;
864
865out:
866 current->backing_dev_info = NULL;
867 mutex_unlock(&inode->i_mutex);
868
869 return written ? written : err;
870}
871
680static void fuse_release_user_pages(struct fuse_req *req, int write) 872static void fuse_release_user_pages(struct fuse_req *req, int write)
681{ 873{
682 unsigned i; 874 unsigned i;
@@ -1203,7 +1395,7 @@ static const struct file_operations fuse_file_operations = {
1203 .read = do_sync_read, 1395 .read = do_sync_read,
1204 .aio_read = fuse_file_aio_read, 1396 .aio_read = fuse_file_aio_read,
1205 .write = do_sync_write, 1397 .write = do_sync_write,
1206 .aio_write = generic_file_aio_write, 1398 .aio_write = fuse_file_aio_write,
1207 .mmap = fuse_file_mmap, 1399 .mmap = fuse_file_mmap,
1208 .open = fuse_open, 1400 .open = fuse_open,
1209 .flush = fuse_flush, 1401 .flush = fuse_flush,