[PATCH 1/3] ceph: Make ceph_netfs_issue_op() handle inlined data (untested)

[David Howells <dhowells@xxxxxxxxxx>]

Mak ceph_netfs_issue_op() handle inlined data on page 0.  The code that's
upstream *ought* to be doing this in ceph_readpage() as the page isn't
pinned and could get discarded under memory pressure from what can be seen.

Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
cc: ceph-devel@xxxxxxxxxxxxxxx
---

 fs/ceph/addr.c |   79 ++++++++++++++++++++++++++++++++++++++++++++------------
 1 file changed, 62 insertions(+), 17 deletions(-)

diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
index c98e5238a1b6..11273108e924 100644
--- a/fs/ceph/addr.c
+++ b/fs/ceph/addr.c
@@ -245,6 +245,61 @@ static void finish_netfs_read(struct ceph_osd_request *req)
 	iput(req->r_inode);
 }
 
+static bool ceph_netfs_issue_op_inline(struct netfs_read_subrequest *subreq)
+{
+	struct netfs_read_request *rreq = subreq->rreq;
+	struct inode *inode = rreq->inode;
+	struct ceph_mds_reply_info_parsed *rinfo;
+	struct ceph_mds_reply_info_in *iinfo;
+	struct ceph_mds_request *req;
+	struct ceph_mds_client *mdsc = ceph_sb_to_mdsc(inode->i_sb);
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	struct iov_iter iter;
+	ssize_t err = 0;
+	size_t len;
+
+	__set_bit(NETFS_SREQ_CLEAR_TAIL, &subreq->flags);
+	__clear_bit(NETFS_SREQ_WRITE_TO_CACHE, &subreq->flags);
+
+	if (subreq->start >= inode->i_size || subreq->start >= 4096)
+		goto out;
+
+	/* We need to fetch the inline data. */
+	req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_GETATTR, USE_ANY_MDS);
+	if (IS_ERR(req)) {
+		err = PTR_ERR(req);
+		goto out;
+	}
+	req->r_ino1 = ci->i_vino;
+	req->r_args.getattr.mask = cpu_to_le32(CEPH_STAT_CAP_INLINE_DATA);
+	req->r_num_caps = 2;
+
+	err = ceph_mdsc_do_request(mdsc, NULL, req);
+	if (err < 0)
+		goto out;
+
+	rinfo = &req->r_reply_info;
+	iinfo = &rinfo->targeti;
+	if (iinfo->inline_version == CEPH_INLINE_NONE) {
+		/* The data got uninlined */
+		ceph_mdsc_put_request(req);
+		return false;
+	}
+
+	len = min_t(size_t, 4096 - subreq->start, iinfo->inline_len);
+	iov_iter_xarray(&iter, READ, &rreq->mapping->i_pages, subreq->start, len);
+
+	err = copy_to_iter(iinfo->inline_data, len, &iter);
+	if (err == 0)
+		err = -EFAULT;
+
+	ceph_mdsc_put_request(req);
+
+out:
+	netfs_subreq_terminated(subreq, err, false);
+	return true;
+}
+
 static void ceph_netfs_issue_op(struct netfs_read_subrequest *subreq)
 {
 	struct netfs_read_request *rreq = subreq->rreq;
@@ -259,6 +314,10 @@ static void ceph_netfs_issue_op(struct netfs_read_subrequest *subreq)
 	int err = 0;
 	u64 len = subreq->len;
 
+	if (ci->i_inline_version != CEPH_INLINE_NONE &&
+	    ceph_netfs_issue_op_inline(subreq))
+		return;
+
 	req = ceph_osdc_new_request(&fsc->client->osdc, &ci->i_layout, vino, subreq->start, &len,
 			0, 1, CEPH_OSD_OP_READ,
 			CEPH_OSD_FLAG_READ | fsc->client->osdc.client->options->read_from_replica,
@@ -327,23 +386,9 @@ static int ceph_readpage(struct file *file, struct page *subpage)
 	size_t len = folio_size(folio);
 	u64 off = folio_file_pos(folio);
 
-	if (ci->i_inline_version != CEPH_INLINE_NONE) {
-		/*
-		 * Uptodate inline data should have been added
-		 * into page cache while getting Fcr caps.
-		 */
-		if (off == 0) {
-			folio_unlock(folio);
-			return -EINVAL;
-		}
-		zero_user_segment(&folio->page, 0, folio_size(folio));
-		folio_mark_uptodate(folio);
-		folio_unlock(folio);
-		return 0;
-	}
-
-	dout("readpage ino %llx.%llx file %p off %llu len %zu folio %p index %lu\n",
-	     vino.ino, vino.snap, file, off, len, folio, folio_index(folio));
+	if (ci->i_inline_version == CEPH_INLINE_NONE)
+		dout("readpage ino %llx.%llx file %p off %llu len %zu folio %p index %lu\n",
+		     vino.ino, vino.snap, file, off, len, folio, folio_index(folio));
 
 	return netfs_readpage(file, folio, &ceph_netfs_read_ops, NULL);
 }