ceph: OSD client
The OSD client is responsible for reading and writing data from/to the
object storage pool. This includes determining where objects are
stored in the cluster, and ensuring that requests are retried or
redirected in the event of a node failure or data migration.
If an OSD does not respond before a timeout expires, keepalive
messages are sent across the lossless, ordered communications channel
to ensure that any break in the TCP is discovered. If the session
does reset, a reconnection is attempted and affected requests are
resent (by the message transport layer).
Signed-off-by: Sage Weil <sage@newdream.net>
diff --git a/fs/ceph/osd_client.h b/fs/ceph/osd_client.h
new file mode 100644
index 0000000..9a4addf
--- /dev/null
+++ b/fs/ceph/osd_client.h
@@ -0,0 +1,144 @@
+#ifndef _FS_CEPH_OSD_CLIENT_H
+#define _FS_CEPH_OSD_CLIENT_H
+
+#include <linux/completion.h>
+#include <linux/mempool.h>
+#include <linux/rbtree.h>
+
+#include "types.h"
+#include "osdmap.h"
+#include "messenger.h"
+
+struct ceph_msg;
+struct ceph_snap_context;
+struct ceph_osd_request;
+struct ceph_osd_client;
+
+/*
+ * completion callback for async writepages
+ */
+typedef void (*ceph_osdc_callback_t)(struct ceph_osd_request *,
+ struct ceph_msg *);
+
+/* a given osd we're communicating with */
+struct ceph_osd {
+ atomic_t o_ref;
+ struct ceph_osd_client *o_osdc;
+ int o_osd;
+ int o_incarnation;
+ struct rb_node o_node;
+ struct ceph_connection o_con;
+ struct list_head o_requests;
+};
+
+/* an in-flight request */
+struct ceph_osd_request {
+ u64 r_tid; /* unique for this client */
+ struct rb_node r_node;
+ struct list_head r_osd_item;
+ struct ceph_osd *r_osd;
+
+ struct ceph_msg *r_request, *r_reply;
+ int r_result;
+ int r_flags; /* any additional flags for the osd */
+ u32 r_sent; /* >0 if r_request is sending/sent */
+ int r_prepared_pages, r_got_reply;
+
+ struct ceph_osd_client *r_osdc;
+ atomic_t r_ref;
+ bool r_mempool;
+ struct completion r_completion, r_safe_completion;
+ ceph_osdc_callback_t r_callback, r_safe_callback;
+ struct ceph_eversion r_reassert_version;
+ struct list_head r_unsafe_item;
+
+ struct inode *r_inode; /* for use by callbacks */
+ struct writeback_control *r_wbc; /* ditto */
+
+ char r_oid[40]; /* object name */
+ int r_oid_len;
+ unsigned long r_timeout_stamp;
+ bool r_resend; /* msg send failed, needs retry */
+
+ struct ceph_file_layout r_file_layout;
+ struct ceph_snap_context *r_snapc; /* snap context for writes */
+ unsigned r_num_pages; /* size of page array (follows) */
+ struct page **r_pages; /* pages for data payload */
+ int r_pages_from_pool;
+ int r_own_pages; /* if true, i own page list */
+};
+
+struct ceph_osd_client {
+ struct ceph_client *client;
+
+ struct ceph_osdmap *osdmap; /* current map */
+ struct rw_semaphore map_sem;
+ struct completion map_waiters;
+ u64 last_requested_map;
+
+ struct mutex request_mutex;
+ struct rb_root osds; /* osds */
+ u64 timeout_tid; /* tid of timeout triggering rq */
+ u64 last_tid; /* tid of last request */
+ struct rb_root requests; /* pending requests */
+ int num_requests;
+ struct delayed_work timeout_work;
+ struct dentry *debugfs_file;
+
+ mempool_t *req_mempool;
+
+ struct ceph_msgpool msgpool_op;
+ struct ceph_msgpool msgpool_op_reply;
+};
+
+extern int ceph_osdc_init(struct ceph_osd_client *osdc,
+ struct ceph_client *client);
+extern void ceph_osdc_stop(struct ceph_osd_client *osdc);
+
+extern void ceph_osdc_handle_reply(struct ceph_osd_client *osdc,
+ struct ceph_msg *msg);
+extern void ceph_osdc_handle_map(struct ceph_osd_client *osdc,
+ struct ceph_msg *msg);
+
+extern struct ceph_osd_request *ceph_osdc_new_request(struct ceph_osd_client *,
+ struct ceph_file_layout *layout,
+ struct ceph_vino vino,
+ u64 offset, u64 *len, int op, int flags,
+ struct ceph_snap_context *snapc,
+ int do_sync, u32 truncate_seq,
+ u64 truncate_size,
+ struct timespec *mtime,
+ bool use_mempool, int num_reply);
+
+static inline void ceph_osdc_get_request(struct ceph_osd_request *req)
+{
+ atomic_inc(&req->r_ref);
+}
+extern void ceph_osdc_put_request(struct ceph_osd_request *req);
+
+extern int ceph_osdc_start_request(struct ceph_osd_client *osdc,
+ struct ceph_osd_request *req,
+ bool nofail);
+extern int ceph_osdc_wait_request(struct ceph_osd_client *osdc,
+ struct ceph_osd_request *req);
+extern void ceph_osdc_sync(struct ceph_osd_client *osdc);
+
+extern int ceph_osdc_readpages(struct ceph_osd_client *osdc,
+ struct ceph_vino vino,
+ struct ceph_file_layout *layout,
+ u64 off, u64 *plen,
+ u32 truncate_seq, u64 truncate_size,
+ struct page **pages, int nr_pages);
+
+extern int ceph_osdc_writepages(struct ceph_osd_client *osdc,
+ struct ceph_vino vino,
+ struct ceph_file_layout *layout,
+ struct ceph_snap_context *sc,
+ u64 off, u64 len,
+ u32 truncate_seq, u64 truncate_size,
+ struct timespec *mtime,
+ struct page **pages, int nr_pages,
+ int flags, int do_sync, bool nofail);
+
+#endif
+