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Commit 7ce469a5 authored by Yan, Zheng's avatar Yan, Zheng Committed by Ilya Dryomov
Browse files

ceph: fix splice read for no Fc capability case 



When iov_iter type is ITER_PIPE, copy_page_to_iter() increases
the page's reference and add the page to a pipe_buffer. It also
set the pipe_buffer's ops to page_cache_pipe_buf_ops. The comfirm
callback in page_cache_pipe_buf_ops expects the page is from page
cache and uptodate, otherwise it return error.

For ceph_sync_read() case, pages are not from page cache. So we
can't call copy_page_to_iter() when iov_iter type is ITER_PIPE.
The fix is using iov_iter_get_pages_alloc() to allocate pages
for the pipe. (the code is similar to default_file_splice_read)

Signed-off-by: default avatarYan, Zheng <zyan@redhat.com>
parent 2b1ac852

fs/ceph/file.c

+66 −54
Original line number Diff line number Diff line
@@ -458,71 +458,60 @@ enum { 
 * only return a short read to the caller if we hit EOF.

 */

static int striped_read(struct inode *inode,

			u64 off, u64 len,

			u64 pos, u64 len,

			struct page **pages, int num_pages,

			int *checkeof)

			int page_align, int *checkeof)

{

	struct ceph_fs_client *fsc = ceph_inode_to_client(inode);

	struct ceph_inode_info *ci = ceph_inode(inode);

	u64 pos, this_len, left;

	u64 this_len;

	loff_t i_size;

	int page_align, pages_left;

	int read, ret;

	struct page **page_pos;

	int page_idx;

	int ret, read = 0;

	bool hit_stripe, was_short;



	/*

	 * we may need to do multiple reads.  not atomic, unfortunately.

	 */

	pos = off;

	left = len;

	page_pos = pages;

	pages_left = num_pages;

	read = 0;



more:

	page_align = pos & ~PAGE_MASK;

	this_len = left;

	this_len = len;

	page_idx = (page_align + read) >> PAGE_SHIFT;

	ret = ceph_osdc_readpages(&fsc->client->osdc, ceph_vino(inode),

				  &ci->i_layout, pos, &this_len,

				  ci->i_truncate_seq,

				  ci->i_truncate_size,

				  page_pos, pages_left, page_align);

				  ci->i_truncate_seq, ci->i_truncate_size,

				  pages + page_idx, num_pages - page_idx,

				  ((page_align + read) & ~PAGE_MASK));

	if (ret == -ENOENT)

		ret = 0;

	hit_stripe = this_len < left;

	hit_stripe = this_len < len;

	was_short = ret >= 0 && ret < this_len;

	dout("striped_read %llu~%llu (read %u) got %d%s%s\n", pos, left, read,

	dout("striped_read %llu~%llu (read %u) got %d%s%s\n", pos, len, read,

	     ret, hit_stripe ? " HITSTRIPE" : "", was_short ? " SHORT" : "");



	i_size = i_size_read(inode);

	if (ret >= 0) {

		int didpages;

		if (was_short && (pos + ret < i_size)) {

			int zlen = min(this_len - ret, i_size - pos - ret);

			int zoff = (off & ~PAGE_MASK) + read + ret;

			int zoff = page_align + read + ret;

			dout(" zero gap %llu to %llu\n",

			     pos + ret, pos + ret + zlen);

			ceph_zero_page_vector_range(zoff, zlen, pages);

			ret += zlen;

		}



		didpages = (page_align + ret) >> PAGE_SHIFT;

		read += ret;

		pos += ret;

		read = pos - off;

		left -= ret;

		page_pos += didpages;

		pages_left -= didpages;

		len -= ret;



		/* hit stripe and need continue*/

		if (left && hit_stripe && pos < i_size)

		if (len && hit_stripe && pos < i_size)

			goto more;

	}



	if (read > 0) {

		ret = read;

		/* did we bounce off eof? */

		if (pos + left > i_size)

		if (pos + len > i_size)

			*checkeof = CHECK_EOF;

	}
@@ -536,15 +525,16 @@ static int striped_read(struct inode *inode, 
 *

 * If the read spans object boundary, just do multiple reads.

 */

static ssize_t ceph_sync_read(struct kiocb *iocb, struct iov_iter *i,

static ssize_t ceph_sync_read(struct kiocb *iocb, struct iov_iter *to,

			      int *checkeof)

{

	struct file *file = iocb->ki_filp;

	struct inode *inode = file_inode(file);

	struct page **pages;

	u64 off = iocb->ki_pos;

	int num_pages, ret;

	size_t len = iov_iter_count(i);

	int num_pages;

	ssize_t ret;

	size_t len = iov_iter_count(to);



	dout("sync_read on file %p %llu~%u %s\n", file, off,

	     (unsigned)len,
@@ -563,12 +553,31 @@ static ssize_t ceph_sync_read(struct kiocb *iocb, struct iov_iter *i, 
	if (ret < 0)

		return ret;



	if (unlikely(to->type & ITER_PIPE)) {

		size_t page_off;

		ret = iov_iter_get_pages_alloc(to, &pages, len,

					       &page_off);

		if (ret <= 0)

			return -ENOMEM;

		num_pages = DIV_ROUND_UP(ret + page_off, PAGE_SIZE);



		ret = striped_read(inode, off, ret, pages, num_pages,

				   page_off, checkeof);

		if (ret > 0) {

			iov_iter_advance(to, ret);

			off += ret;

		} else {

			iov_iter_advance(to, 0);

		}

		ceph_put_page_vector(pages, num_pages, false);

	} else {

		num_pages = calc_pages_for(off, len);

		pages = ceph_alloc_page_vector(num_pages, GFP_KERNEL);

		if (IS_ERR(pages))

			return PTR_ERR(pages);

	ret = striped_read(inode, off, len, pages,

				num_pages, checkeof);



		ret = striped_read(inode, off, len, pages, num_pages,

				   (off & ~PAGE_MASK), checkeof);

		if (ret > 0) {

			int l, k = 0;

			size_t left = ret;
@@ -577,7 +586,8 @@ static ssize_t ceph_sync_read(struct kiocb *iocb, struct iov_iter *i, 
				size_t page_off = off & ~PAGE_MASK;

				size_t copy = min_t(size_t, left,

						    PAGE_SIZE - page_off);

			l = copy_page_to_iter(pages[k++], page_off, copy, i);

				l = copy_page_to_iter(pages[k++], page_off,

						      copy, to);

				off += l;

				left -= l;

				if (l < copy)
@@ -585,13 +595,14 @@ static ssize_t ceph_sync_read(struct kiocb *iocb, struct iov_iter *i, 
			}

		}

		ceph_release_page_vector(pages, num_pages);

	}



	if (off > iocb->ki_pos) {

		ret = off - iocb->ki_pos;

		iocb->ki_pos = off;

	}



	dout("sync_read result %d\n", ret);

	dout("sync_read result %zd\n", ret);

	return ret;

}
@@ -1771,6 +1782,7 @@ const struct file_operations ceph_file_fops = { 
	.fsync = ceph_fsync,

	.lock = ceph_lock,

	.flock = ceph_flock,

	.splice_read = generic_file_splice_read,

	.splice_write = iter_file_splice_write,

	.unlocked_ioctl = ceph_ioctl,

	.compat_ioctl	= ceph_ioctl,