For readv/preadv sync-operatoin, ceph only do the first iov.
It don't think other iovs.Now implement this.

V2:
  -add generic_segment_checks
  -using struct iov_iter replace cloning the iovs.
  -return previous successfully copied if ceph_copy_page_vector_to_user
   met error.

Signed-off-by: Jianpeng Ma <majianp...@gmail.com>
---
 fs/ceph/file.c | 174 ++++++++++++++++++++++++++++++++++++++++-----------------
 1 file changed, 123 insertions(+), 51 deletions(-)

diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index 3de8982..1c28c52 100644
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -408,51 +408,109 @@ 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;
-       int num_pages, ret;
+       u64 off = iocb->ki_pos;
+       int num_pages, ret, n;
 
-       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)iocb->ki_left,
             (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 + iocb->ki_left);
        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) {
+               for (n = 0; n < i->nr_segs; n++) {
+                       void __user *data = i->iov[n].iov_base;
+                       size_t len = i->iov[n].iov_len;
+
+                       if (n == 0) {
+                               len -=  i->iov_offset;
+                               data += 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;
+                       if (ret < len)
+                               break;
+               }
 
-       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;
+                       iocb->ki_left -= ret;
+               }
+       } else {
+               size_t len = iocb->ki_left;
 
-done:
-       if (file->f_flags & O_DIRECT)
-               ceph_put_page_vector(pages, 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);
+               ret = striped_read(inode, off, len, pages,
+                                       num_pages, checkeof, 0, 0);
+               len = ret;
+               if (len) {
+                       int l, k = 0;
+                       size_t left = len;
+
+                       for (n = 0; n < i->nr_segs && left; n++) {
+                               void __user *data = i->iov[n].iov_base;
+                               l = min(left, i->iov[n].iov_len);
+
+                               if (n == 0) {
+                                       data += 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) {
+                                       left -= ret;
+                                       off += ret;
+                                       k = calc_pages_for(iocb->ki_pos,
+                                                          len - left + 1) - 1;
+                                       BUG_ON(k >= num_pages && left);
+                               } else
+                                       break;
+                       }
+
+                       len -= left;
+                       if (len > 0) {
+                               iocb->ki_pos += len;
+                               iocb->ki_left -= len;
+                               ret = len;
+                       }
+               }
                ceph_release_page_vector(pages, num_pages);
+       }
+
        dout("sync_read result %d\n", ret);
        return ret;
 }
@@ -647,55 +705,69 @@ 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 = 0;
        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:
+
+       ret = generic_segment_checks(iov, &nr_segs, &len, VERIFY_WRITE);
+       if (ret)
+               return ret;
+
        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;
+               return ret;
+
        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));
 
        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;
+
+               iocb->ki_left = len;
+               iov_iter_init(&i, iov, nr_segs, len, 0);
+again:
                /* hmm, this isn't really async... */
-               ret = ceph_sync_read(filp, base, len, ppos, &checkeof);
-       else
+               ret = ceph_sync_read(iocb, &i, &checkeof);
+
+               if (checkeof && ret >= 0) {
+                       int statret = ceph_do_getattr(inode,
+                                                     CEPH_STAT_CAP_SIZE);
+
+                       /* hit EOF or hole? */
+                       if (statret == 0 && iocb->ki_pos < inode->i_size &&
+                               iocb->ki_left) {
+                               dout("sync_read hit hole, ppos %lld < size %lld"
+                                    ", reading more\n", iocb->ki_pos,
+                                    inode->i_size);
+
+                               read += ret;
+                               iov_iter_advance(&i, ret);
+                               checkeof = 0;
+                               goto again;
+                       }
+               }
+
+       } else
                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);
-
-               /* 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);
-                       read += ret;
-                       base += ret;
-                       len -= ret;
-                       checkeof = 0;
-                       goto again;
-               }
-       }
        if (ret >= 0)
                ret += read;
 
-- 
1.8.1.2

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