Commit c5c6b19d authored by Sage Weil's avatar Sage Weil
Browse files

ceph: explicitly specify page alignment in network messages 



The alignment used for reading data into or out of pages used to be taken
from the data_off field in the message header.  This only worked as long
as the page alignment matched the object offset, breaking direct io to
non-page aligned offsets.

Instead, explicitly specify the page alignment next to the page vector
in the ceph_msg struct, and use that instead of the message header (which
probably shouldn't be trusted).  The alloc_msg callback is responsible for
filling in this field properly when it sets up the page vector.

Signed-off-by: default avatarSage Weil <sage@newdream.net>
parent b7495fc2

include/linux/ceph/messenger.h

+1 −0
Original line number Diff line number Diff line
@@ -82,6 +82,7 @@ struct ceph_msg { 
	struct ceph_buffer *middle;

	struct page **pages;            /* data payload.  NOT OWNER. */

	unsigned nr_pages;              /* size of page array */

	unsigned page_alignment;        /* io offset in first page */

	struct ceph_pagelist *pagelist; /* instead of pages */

	struct list_head list_head;

	struct kref kref;

net/ceph/messenger.c

+5 −5
Original line number Diff line number Diff line
@@ -540,8 +540,7 @@ static void prepare_write_message(struct ceph_connection *con) 
		/* initialize page iterator */

		con->out_msg_pos.page = 0;

		if (m->pages)

			con->out_msg_pos.page_pos =

				le16_to_cpu(m->hdr.data_off) & ~PAGE_MASK;

			con->out_msg_pos.page_pos = m->page_alignment;

		else

			con->out_msg_pos.page_pos = 0;

		con->out_msg_pos.data_pos = 0;
@@ -1491,7 +1490,7 @@ static int read_partial_message(struct ceph_connection *con) 
	struct ceph_msg *m = con->in_msg;

	int ret;

	int to, left;

	unsigned front_len, middle_len, data_len, data_off;

	unsigned front_len, middle_len, data_len;

	int datacrc = con->msgr->nocrc;

	int skip;

	u64 seq;
@@ -1527,7 +1526,6 @@ static int read_partial_message(struct ceph_connection *con) 
	data_len = le32_to_cpu(con->in_hdr.data_len);

	if (data_len > CEPH_MSG_MAX_DATA_LEN)

		return -EIO;

	data_off = le16_to_cpu(con->in_hdr.data_off);



	/* verify seq# */

	seq = le64_to_cpu(con->in_hdr.seq);
@@ -1575,7 +1573,7 @@ static int read_partial_message(struct ceph_connection *con) 


		con->in_msg_pos.page = 0;

		if (m->pages)

			con->in_msg_pos.page_pos = data_off & ~PAGE_MASK;

			con->in_msg_pos.page_pos = m->page_alignment;

		else

			con->in_msg_pos.page_pos = 0;

		con->in_msg_pos.data_pos = 0;
@@ -2300,6 +2298,7 @@ struct ceph_msg *ceph_msg_new(int type, int front_len, gfp_t flags) 


	/* data */

	m->nr_pages = 0;

	m->page_alignment = 0;

	m->pages = NULL;

	m->pagelist = NULL;

	m->bio = NULL;
@@ -2369,6 +2368,7 @@ static struct ceph_msg *ceph_alloc_msg(struct ceph_connection *con, 
			       type, front_len);

			return NULL;

		}

		msg->page_alignment = le16_to_cpu(hdr->data_off);

	}

	memcpy(&msg->hdr, &con->in_hdr, sizeof(con->in_hdr));

net/ceph/osd_client.c

+3 −0
Original line number Diff line number Diff line
@@ -391,6 +391,8 @@ void ceph_osdc_build_request(struct ceph_osd_request *req, 
		req->r_request->hdr.data_len = cpu_to_le32(data_len);

	}



	req->r_request->page_alignment = req->r_page_alignment;



	BUG_ON(p > msg->front.iov_base + msg->front.iov_len);

	msg_size = p - msg->front.iov_base;

	msg->front.iov_len = msg_size;
@@ -1657,6 +1659,7 @@ static struct ceph_msg *get_reply(struct ceph_connection *con, 
		}

		m->pages = req->r_pages;

		m->nr_pages = req->r_num_pages;

		m->page_alignment = req->r_page_alignment;

#ifdef CONFIG_BLOCK

		m->bio = req->r_bio;

#endif

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