ceph: align data in pages in ceph_sync_write

Encrypted files will need to be dealt with in block-sized chunks and
once we do that, the way that ceph_sync_write aligns the data in the
bounce buffer won't be acceptable.

Change it to align the data the same way it would be aligned in the
pagecache.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Xiubo Li <xiubli@redhat.com>
Reviewed-and-tested-by: Luís Henriques <lhenriques@suse.de>
Reviewed-by: Milind Changire <mchangir@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index f4c3da5..0abe363 100644 (file)
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -1582,6 +1582,7 @@ ceph_sync_write(struct kiocb *iocb, struct iov_iter *from, loff_t pos,
        bool check_caps = false;
        struct timespec64 mtime = current_time(inode);
        size_t count = iov_iter_count(from);
+       size_t off;
 
        if (ceph_snap(file_inode(file)) != CEPH_NOSNAP)
                return -EROFS;
@@ -1619,12 +1620,7 @@ ceph_sync_write(struct kiocb *iocb, struct iov_iter *from, loff_t pos,
                        break;
                }
 
-               /*
-                * write from beginning of first page,
-                * regardless of io alignment
-                */
-               num_pages = (len + PAGE_SIZE - 1) >> PAGE_SHIFT;
-
+               num_pages = calc_pages_for(pos, len);
                pages = ceph_alloc_page_vector(num_pages, GFP_KERNEL);
                if (IS_ERR(pages)) {
                        ret = PTR_ERR(pages);
@@ -1632,9 +1628,12 @@ ceph_sync_write(struct kiocb *iocb, struct iov_iter *from, loff_t pos,
                }
 
                left = len;
+               off = offset_in_page(pos);
                for (n = 0; n < num_pages; n++) {
-                       size_t plen = min_t(size_t, left, PAGE_SIZE);
-                       ret = copy_page_from_iter(pages[n], 0, plen, from);
+                       size_t plen = min_t(size_t, left, PAGE_SIZE - off);
+
+                       ret = copy_page_from_iter(pages[n], off, plen, from);
+                       off = 0;
                        if (ret != plen) {
                                ret = -EFAULT;
                                break;
@@ -1649,8 +1648,9 @@ ceph_sync_write(struct kiocb *iocb, struct iov_iter *from, loff_t pos,
 
                req->r_inode = inode;
 
-               osd_req_op_extent_osd_data_pages(req, 0, pages, len, 0,
-                                               false, true);
+               osd_req_op_extent_osd_data_pages(req, 0, pages, len,
+                                                offset_in_page(pos),
+                                                false, true);
 
                req->r_mtime = mtime;
                ceph_osdc_start_request(&fsc->client->osdc, req);