From ec3bc567eac12c557a2b99bd0b34b5dff12cab23 Mon Sep 17 00:00:00 2001 From: Jeff Layton Date: Tue, 25 Jan 2022 08:26:31 -0500 Subject: libceph: new sparse_read op, support sparse reads on msgr2 crc codepath MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Add support for a new sparse_read ceph_connection operation. The idea is that the client driver can define this operation use it to do special handling for incoming reads. The alloc_msg routine will look at the request and determine whether the reply is expected to be sparse. If it is, then we'll dispatch to a different set of state machine states that will repeatedly call the driver's sparse_read op to get length and placement info for reading the extent map, and the extents themselves. This necessitates adding some new field to some other structs: - The msg gets a new bool to track whether it's a sparse_read request. - A new field is added to the cursor to track the amount remaining in the current extent. This is used to cap the read from the socket into the msg_data - Handing a revoke with all of this is particularly difficult, so I've added a new data_len_remain field to the v2 connection info, and then use that to skip that much on a revoke. We may want to expand the use of that to the normal read path as well, just for consistency's sake. Signed-off-by: Jeff Layton Reviewed-by: Xiubo Li Reviewed-and-tested-by: Luís Henriques Reviewed-by: Milind Changire Signed-off-by: Ilya Dryomov --- include/linux/ceph/messenger.h | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) (limited to 'include/linux') diff --git a/include/linux/ceph/messenger.h b/include/linux/ceph/messenger.h index 99c1726be6ee..8a6938fa324e 100644 --- a/include/linux/ceph/messenger.h +++ b/include/linux/ceph/messenger.h @@ -17,6 +17,7 @@ struct ceph_msg; struct ceph_connection; +struct ceph_msg_data_cursor; /* * Ceph defines these callbacks for handling connection events. @@ -70,6 +71,30 @@ struct ceph_connection_operations { int used_proto, int result, const int *allowed_protos, int proto_cnt, const int *allowed_modes, int mode_cnt); + + /** + * sparse_read: read sparse data + * @con: connection we're reading from + * @cursor: data cursor for reading extents + * @buf: optional buffer to read into + * + * This should be called more than once, each time setting up to + * receive an extent into the current cursor position, and zeroing + * the holes between them. + * + * Returns amount of data to be read (in bytes), 0 if reading is + * complete, or -errno if there was an error. + * + * If @buf is set on a >0 return, then the data should be read into + * the provided buffer. Otherwise, it should be read into the cursor. + * + * The sparse read operation is expected to initialize the cursor + * with a length covering up to the end of the last extent. + */ + int (*sparse_read)(struct ceph_connection *con, + struct ceph_msg_data_cursor *cursor, + char **buf); + }; /* use format string %s%lld */ @@ -207,6 +232,7 @@ struct ceph_msg_data_cursor { struct ceph_msg_data *data; /* current data item */ size_t resid; /* bytes not yet consumed */ + int sr_resid; /* residual sparse_read len */ bool need_crc; /* crc update needed */ union { #ifdef CONFIG_BLOCK @@ -251,6 +277,7 @@ struct ceph_msg { struct kref kref; bool more_to_follow; bool needs_out_seq; + bool sparse_read; int front_alloc_len; struct ceph_msgpool *pool; @@ -395,6 +422,7 @@ struct ceph_connection_v2_info { void *conn_bufs[16]; int conn_buf_cnt; + int data_len_remain; struct kvec in_sign_kvecs[8]; struct kvec out_sign_kvecs[8]; -- cgit v1.2.3-70-g09d2