On 09/06/2013 04:48 PM, majianpeng wrote:
> 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 <[email protected]>
> ---
> 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;
> + }
I think it's better to call iov_iter_advance() here instead of in
ceph_aio_read(),
and change the code to something like:
----
while (iov_iter_count(&i) && left > 0) {
void __user *data = i->iov->iov_base + i->iov_offset;
l = min(left, i->iov->iov_len - i->iov_offset);
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;
}
rest change looks good.
Regards
Yan, Zheng
> +
> + 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;
>
>
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