[PATCH] ceph: fix memory leak in ceph_direct_read_write()

[Ilya Dryomov <idryomov@xxxxxxxxx>]

The bvecs array which is allocated in iter_get_bvecs_alloc() is leaked
and pages remain pinned if ceph_alloc_sparse_ext_map() fails.

There is no need to delay the allocation of sparse_ext map until after
the bvecs array is set up, so fix this by moving sparse_ext allocation
a bit earlier.  Also, make a similar adjustment in __ceph_sync_read()
for consistency (a leak of the same kind in __ceph_sync_read() has been
addressed differently).

Cc: stable@xxxxxxxxxxxxxxx
Fixes: 03bc06c7b0bd ("ceph: add new mount option to enable sparse reads")
Signed-off-by: Ilya Dryomov <idryomov@xxxxxxxxx>
Reviewed-by: Alex Markuze <amarkuze@xxxxxxxxxx>

diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index 8e0400d461a2..67468d88f139 100644
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -1116,6 +1116,16 @@ ssize_t __ceph_sync_read(struct inode *inode, loff_t *ki_pos,
 			len = read_off + read_len - off;
 		more = len < iov_iter_count(to);
 
+		op = &req->r_ops[0];
+		if (sparse) {
+			extent_cnt = __ceph_sparse_read_ext_count(inode, read_len);
+			ret = ceph_alloc_sparse_ext_map(op, extent_cnt);
+			if (ret) {
+				ceph_osdc_put_request(req);
+				break;
+			}
+		}
+
 		num_pages = calc_pages_for(read_off, read_len);
 		page_off = offset_in_page(off);
 		pages = ceph_alloc_page_vector(num_pages, GFP_KERNEL);
@@ -1129,16 +1139,6 @@ ssize_t __ceph_sync_read(struct inode *inode, loff_t *ki_pos,
 						 offset_in_page(read_off),
 						 false, true);
 
-		op = &req->r_ops[0];
-		if (sparse) {
-			extent_cnt = __ceph_sparse_read_ext_count(inode, read_len);
-			ret = ceph_alloc_sparse_ext_map(op, extent_cnt);
-			if (ret) {
-				ceph_osdc_put_request(req);
-				break;
-			}
-		}
-
 		ceph_osdc_start_request(osdc, req);
 		ret = ceph_osdc_wait_request(osdc, req);
 
@@ -1551,6 +1551,16 @@ ceph_direct_read_write(struct kiocb *iocb, struct iov_iter *iter,
 			break;
 		}
 
+		op = &req->r_ops[0];
+		if (sparse) {
+			extent_cnt = __ceph_sparse_read_ext_count(inode, size);
+			ret = ceph_alloc_sparse_ext_map(op, extent_cnt);
+			if (ret) {
+				ceph_osdc_put_request(req);
+				break;
+			}
+		}
+
 		len = iter_get_bvecs_alloc(iter, size, &bvecs, &num_pages);
 		if (len < 0) {
 			ceph_osdc_put_request(req);
@@ -1560,6 +1570,8 @@ ceph_direct_read_write(struct kiocb *iocb, struct iov_iter *iter,
 		if (len != size)
 			osd_req_op_extent_update(req, 0, len);
 
+		osd_req_op_extent_osd_data_bvecs(req, 0, bvecs, num_pages, len);
+
 		/*
 		 * To simplify error handling, allow AIO when IO within i_size
 		 * or IO can be satisfied by single OSD request.
@@ -1591,17 +1603,6 @@ ceph_direct_read_write(struct kiocb *iocb, struct iov_iter *iter,
 			req->r_mtime = mtime;
 		}
 
-		osd_req_op_extent_osd_data_bvecs(req, 0, bvecs, num_pages, len);
-		op = &req->r_ops[0];
-		if (sparse) {
-			extent_cnt = __ceph_sparse_read_ext_count(inode, size);
-			ret = ceph_alloc_sparse_ext_map(op, extent_cnt);
-			if (ret) {
-				ceph_osdc_put_request(req);
-				break;
-			}
-		}
-
 		if (aio_req) {
 			aio_req->total_len += len;
 			aio_req->num_reqs++;