On 09/24/2013 04:05 PM, majianpeng wrote:
> diff --git a/fs/ceph/file.c b/fs/ceph/file.c
> index 3de8982..5422d8e 100644
> --- a/fs/ceph/file.c
> +++ b/fs/ceph/file.c
> @@ -408,51 +408,94 @@ 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;
>  
> -     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;
> -
> -     ret = striped_read(inode, off, len, pages, num_pages, checkeof,
> -                        file->f_flags & O_DIRECT,
> -                        (unsigned long)data & ~PAGE_MASK);
> +             return ret;
>  
> -     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 (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 {
> +             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);
> +             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 (off > iocb->ki_pos) {
> +             ret = off - iocb->ki_pos;
> +             iocb->ki_pos = off;
> +             iocb->ki_left -= ret;
> +     }
> +
>       dout("sync_read result %d\n", ret);
>       return ret;
>  }
> @@ -647,17 +690,16 @@ 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;

len = iocb->ki_left;

>       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;
>  

I think we should put label 'again' here.

>       dout("aio_read %p %llx.%llx %llu~%u trying to get caps on %p\n",
>            inode, ceph_vinop(inode), pos, (unsigned)len, inode);
> +
>  again:
>       if (fi->fmode & CEPH_FILE_MODE_LAZY)
>               want = CEPH_CAP_FILE_CACHE | CEPH_CAP_FILE_LAZYIO;
> @@ -665,38 +707,61 @@ again:
>               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;
> +
> +             if (!read) {
> +                     ret = generic_segment_checks(iov, &nr_segs,
> +                                                     &len, VERIFY_WRITE);
> +                     if (ret)
> +                             goto out;
> +             }
> +
> +             iocb->ki_left = len;

iocb->ki_left = len - read ?


> +             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 = 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;

forget to set 'read' to 0 ?


>               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 &&
> +                     iocb->ki_left) {
> +                     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)
> +
> +     if (ret > 0)
>               ret += read;

what is the purpose of this change ?

Regards
Yan, Zheng
>  
>       return ret;
> -- 

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