[PATCH v13 02/59] libceph: define struct ceph_sparse_extent and add some helpers

Jeff Layton
2022-04-05T20:15:26Z

When the OSD sends back a sparse read reply, it contains an array of
these structures. Define the structure and add a couple of helpers for
dealing with them.

Also add a place in struct ceph_osd_req_op to store the extent buffer,
and code to free it if it's populated when the req is torn down.

Reviewed-by: Xiubo Li <xiubli@redhat.com>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
include/linux/ceph/osd_client.h | 43 ++++++++++++++++++++++++++++++++-
net/ceph/osd_client.c | 13 ++++++++++
2 files changed, 55 insertions(+), 1 deletion(-)

diff --git a/include/linux/ceph/osd_client.h b/include/linux/ceph/osd_client.h
index 3122c1a3205f..1dd02240d00d 100644
--- a/include/linux/ceph/osd_client.h
+++ b/include/linux/ceph/osd_client.h
@@ -29,6 +29,17 @@ typedef void (*ceph_osdc_callback_t)(struct ceph_osd_request *);

#define CEPH_HOMELESS_OSD -1

+/*
+ * A single extent in a SPARSE_READ reply.
+ *
+ * Note that these come from the OSD as little-endian values. On BE arches,
+ * we convert them in-place after receipt.
+ */
+struct ceph_sparse_extent {
+ u64 off;
+ u64 len;
+} __packed;
+
/*
* A given osd we're communicating with.
*
@@ -104,6 +115,8 @@ struct ceph_osd_req_op {
u64 offset, length;
u64 truncate_size;
u32 truncate_seq;
+ int sparse_ext_cnt;
+ struct ceph_sparse_extent *sparse_ext;
struct ceph_osd_data osd_data;
} extent;
struct {
@@ -507,6 +520,20 @@ extern struct ceph_osd_request *ceph_osdc_new_request(struct ceph_osd_client *,
u32 truncate_seq, u64 truncate_size,
bool use_mempool);

+int __ceph_alloc_sparse_ext_map(struct ceph_osd_req_op *op, int cnt);
+
+/*
+ * How big an extent array should we preallocate for a sparse read? This is
+ * just a starting value. If we get more than this back from the OSD, the
+ * receiver will reallocate.
+ */
+#define CEPH_SPARSE_EXT_ARRAY_INITIAL 16
+
+static inline int ceph_alloc_sparse_ext_map(struct ceph_osd_req_op *op)
+{
+ return __ceph_alloc_sparse_ext_map(op, CEPH_SPARSE_EXT_ARRAY_INITIAL);
+}
+
extern void ceph_osdc_get_request(struct ceph_osd_request *req);
extern void ceph_osdc_put_request(struct ceph_osd_request *req);

@@ -562,5 +589,19 @@ int ceph_osdc_list_watchers(struct ceph_osd_client *osdc,
struct ceph_object_locator *oloc,
struct ceph_watch_item **watchers,
u32 *num_watchers);
-#endif

+/* Find offset into the buffer of the end of the extent map */
+static inline u64 ceph_sparse_ext_map_end(struct ceph_osd_req_op *op)
+{
+ struct ceph_sparse_extent *ext;
+
+ /* No extents? No data */
+ if (op->extent.sparse_ext_cnt == 0)
+ return 0;
+
+ ext = &op->extent.sparse_ext[op->extent.sparse_ext_cnt - 1];
+
+ return ext->off + ext->len - op->extent.offset;
+}
+
+#endif
diff --git a/net/ceph/osd_client.c b/net/ceph/osd_client.c
index 17c792b32343..c150683f2a2f 100644
--- a/net/ceph/osd_client.c
+++ b/net/ceph/osd_client.c
@@ -378,6 +378,7 @@ static void osd_req_op_data_release(struct ceph_osd_request *osd_req,
case CEPH_OSD_OP_READ:
case CEPH_OSD_OP_WRITE:
case CEPH_OSD_OP_WRITEFULL:
+ kfree(op->extent.sparse_ext);
ceph_osd_data_release(&op->extent.osd_data);
break;
case CEPH_OSD_OP_CALL:
@@ -1141,6 +1142,18 @@ struct ceph_osd_request *ceph_osdc_new_request(struct ceph_osd_client *osdc,
}
EXPORT_SYMBOL(ceph_osdc_new_request);

+int __ceph_alloc_sparse_ext_map(struct ceph_osd_req_op *op, int cnt)
+{
+ op->extent.sparse_ext_cnt = cnt;
+ op->extent.sparse_ext = kmalloc_array(cnt,
+ sizeof(*op->extent.sparse_ext),
+ GFP_NOFS);
+ if (!op->extent.sparse_ext)
+ return -ENOMEM;
+ return 0;
+}
+EXPORT_SYMBOL(__ceph_alloc_sparse_ext_map);
+
/*
* We keep osd requests in an rbtree, sorted by ->r_tid.
*/
--
2.35.1