ceph: implement readv/preadv for sync operation

For readv/preadv sync-operatoin, ceph only do the first iov.
Now implement this.

Signed-off-by: Jianpeng Ma <majianpeng@gmail.com>
Reviewed-by: Yan, Zheng <zheng.z.yan@intel.com>

1 files changed, 116 insertions, 46 deletions

diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index 5cf034e915bb..c4419e848a4f 100644
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -408,51 +408,92 @@ more:
  *
  * If the read spans object boundary, just do multiple reads.
  */
-static ssize_t ceph_sync_read(struct file *file, char __user *data,
-                              unsigned len, loff_t *poff, int *checkeof)
+static ssize_t ceph_sync_read(struct kiocb *iocb, struct iov_iter *i,
+                                int *checkeof)
 {
+        struct file *file = iocb->ki_filp;
         struct inode *inode = file_inode(file);
         struct page **pages;
-        u64 off = *poff;
+        u64 off = iocb->ki_pos;
         int num_pages, ret;
+        size_t len = i->count;
 
-        dout("sync_read on file %p %llu~%u %s\n", file, off, len,
+        dout("sync_read on file %p %llu~%u %s\n", file, off,
+             (unsigned)len,
              (file->f_flags & O_DIRECT) ? "O_DIRECT" : "");
-
-        if (file->f_flags & O_DIRECT) {
-                num_pages = calc_pages_for((unsigned long)data, len);
-                pages = ceph_get_direct_page_vector(data, num_pages, true);
-        } else {
-                num_pages = calc_pages_for(off, len);
-                pages = ceph_alloc_page_vector(num_pages, GFP_NOFS);
-        }
-        if (IS_ERR(pages))
-                return PTR_ERR(pages);
-
         /*
          * flush any page cache pages in this range.  this
          * will make concurrent normal and sync io slow,
          * but it will at least behave sensibly when they are
          * in sequence.
          */
-        ret = filemap_write_and_wait(inode->i_mapping);
+        ret = filemap_write_and_wait_range(inode->i_mapping, off,
+                                                off + len);
         if (ret < 0)
-                goto done;
+                return ret;
 
-        ret = striped_read(inode, off, len, pages, num_pages, checkeof,
-                           file->f_flags & O_DIRECT,
-                           (unsigned long)data & ~PAGE_MASK);
+        if (file->f_flags & O_DIRECT) {
+                while (iov_iter_count(i)) {
+                        void __user *data = i->iov[0].iov_base + i->iov_offset;
+                        size_t len = i->iov[0].iov_len - i->iov_offset;
+
+                        num_pages = calc_pages_for((unsigned long)data, len);
+                        pages = ceph_get_direct_page_vector(data,
+                                                            num_pages, true);
+                        if (IS_ERR(pages))
+                                return PTR_ERR(pages);
+
+                        ret = striped_read(inode, off, len,
+                                           pages, num_pages, checkeof,
+                                           1, (unsigned long)data & ~PAGE_MASK);
+                        ceph_put_page_vector(pages, num_pages, true);
+
+                        if (ret <= 0)
+                                break;
+                        off += ret;
+                        iov_iter_advance(i, ret);
+                        if (ret < len)
+                                break;
+                }
+        } else {
+                num_pages = calc_pages_for(off, len);
+                pages = ceph_alloc_page_vector(num_pages, GFP_NOFS);
+                if (IS_ERR(pages))
+                        return PTR_ERR(pages);
+                ret = striped_read(inode, off, len, pages,
+                                        num_pages, checkeof, 0, 0);
+                if (ret > 0) {
+                        int l, k = 0;
+                        size_t left = len = ret;
+
+                        while (left) {
+                                void __user *data = i->iov[0].iov_base
+                                                        + i->iov_offset;
+                                l = min(i->iov[0].iov_len - i->iov_offset,
+                                        left);
+
+                                ret = ceph_copy_page_vector_to_user(&pages[k],
+                                                                    data, off,
+                                                                    l);
+                                if (ret > 0) {
+                                        iov_iter_advance(i, ret);
+                                        left -= ret;
+                                        off += ret;
+                                        k = calc_pages_for(iocb->ki_pos,
+                                                           len - left + 1) - 1;
+                                        BUG_ON(k >= num_pages && left);
+                                } else
+                                        break;
+                        }
+                }
+                ceph_release_page_vector(pages, num_pages);
+        }
 
-        if (ret >= 0 && (file->f_flags & O_DIRECT) == 0)
-                ret = ceph_copy_page_vector_to_user(pages, data, off, ret);
-        if (ret >= 0)
-                *poff = off + ret;
+        if (off > iocb->ki_pos) {
+                ret = off - iocb->ki_pos;
+                iocb->ki_pos = off;
+        }
 
-done:
-        if (file->f_flags & O_DIRECT)
-                ceph_put_page_vector(pages, num_pages, true);
-        else
-                ceph_release_page_vector(pages, num_pages);
         dout("sync_read result %d\n", ret);
         return ret;
 }
@@ -758,55 +799,84 @@ static ssize_t ceph_aio_read(struct kiocb *iocb, const struct iovec *iov,
 {
         struct file *filp = iocb->ki_filp;
         struct ceph_file_info *fi = filp->private_data;
-        loff_t *ppos = &iocb->ki_pos;
-        size_t len = iov->iov_len;
+        size_t len = iocb->ki_nbytes;
         struct inode *inode = file_inode(filp);
         struct ceph_inode_info *ci = ceph_inode(inode);
-        void __user *base = iov->iov_base;
         ssize_t ret;
         int want, got = 0;
         int checkeof = 0, read = 0;
 
-        dout("aio_read %p %llx.%llx %llu~%u trying to get caps on %p\n",
-             inode, ceph_vinop(inode), pos, (unsigned)len, inode);
 again:
+        dout("aio_read %p %llx.%llx %llu~%u trying to get caps on %p\n",
+             inode, ceph_vinop(inode), iocb->ki_pos, (unsigned)len, inode);
+
         if (fi->fmode & CEPH_FILE_MODE_LAZY)
                 want = CEPH_CAP_FILE_CACHE | CEPH_CAP_FILE_LAZYIO;
         else
                 want = CEPH_CAP_FILE_CACHE;
         ret = ceph_get_caps(ci, CEPH_CAP_FILE_RD, want, &got, -1);
         if (ret < 0)
-                goto out;
-        dout("aio_read %p %llx.%llx %llu~%u got cap refs on %s\n",
-             inode, ceph_vinop(inode), pos, (unsigned)len,
-             ceph_cap_string(got));
+                return ret;
 
         if ((got & (CEPH_CAP_FILE_CACHE|CEPH_CAP_FILE_LAZYIO)) == 0 ||
             (iocb->ki_filp->f_flags & O_DIRECT) ||
-            (fi->flags & CEPH_F_SYNC))
+            (fi->flags & CEPH_F_SYNC)) {
+                struct iov_iter i;
+
+                dout("aio_sync_read %p %llx.%llx %llu~%u got cap refs on %s\n",
+                     inode, ceph_vinop(inode), iocb->ki_pos, (unsigned)len,
+                     ceph_cap_string(got));
+
+                if (!read) {
+                        ret = generic_segment_checks(iov, &nr_segs,
+                                                        &len, VERIFY_WRITE);
+                        if (ret)
+                                goto out;
+                }
+
+                iov_iter_init(&i, iov, nr_segs, len, read);
+
                 /* hmm, this isn't really async... */
-                ret = ceph_sync_read(filp, base, len, ppos, &checkeof);
-        else
-                ret = generic_file_aio_read(iocb, iov, nr_segs, pos);
+                ret = ceph_sync_read(iocb, &i, &checkeof);
+        } else {
+                /*
+                 * We can't modify the content of iov,
+                 * so we only read from beginning.
+                 */
+                if (read) {
+                        iocb->ki_pos = pos;
+                        len = iocb->ki_nbytes;
+                        read = 0;
+                }
+                dout("aio_read %p %llx.%llx %llu~%u got cap refs on %s\n",
+                     inode, ceph_vinop(inode), pos, (unsigned)len,
+                     ceph_cap_string(got));
 
+                ret = generic_file_aio_read(iocb, iov, nr_segs, pos);
+        }
 out:
         dout("aio_read %p %llx.%llx dropping cap refs on %s = %d\n",
              inode, ceph_vinop(inode), ceph_cap_string(got), (int)ret);
         ceph_put_cap_refs(ci, got);
 
         if (checkeof && ret >= 0) {
-                int statret = ceph_do_getattr(inode, CEPH_STAT_CAP_SIZE);
+                int statret = ceph_do_getattr(inode,
+                                              CEPH_STAT_CAP_SIZE);
 
                 /* hit EOF or hole? */
-                if (statret == 0 && *ppos < inode->i_size) {
-                        dout("aio_read sync_read hit hole, ppos %lld < size %lld, reading more\n", *ppos, inode->i_size);
+                if (statret == 0 && iocb->ki_pos < inode->i_size &&
+                        ret < len) {
+                        dout("sync_read hit hole, ppos %lld < size %lld"
+                             ", reading more\n", iocb->ki_pos,
+                             inode->i_size);
+
                         read += ret;
-                        base += ret;
                         len -= ret;
                         checkeof = 0;
                         goto again;
                 }
         }
+
         if (ret >= 0)
                 ret += read;