libceph: variable-sized ceph_object_id

Currently ceph_object_id can hold object names of up to 100
(CEPH_MAX_OID_NAME_LEN) characters.  This is enough for all use cases,
expect one - long rbd image names:

- a format 1 header is named "<imgname>.rbd"
- an object that points to a format 2 header is named "rbd_id.<imgname>"

We operate on these potentially long-named objects during rbd map, and,
for format 1 images, during header refresh.  (A format 2 header name is
a small system-generated string.)

Lift this 100 character limit by making ceph_object_id be able to point
to an externally-allocated string.  Apart from being able to work with
almost arbitrarily-long named objects, this allows us to reduce the
size of ceph_object_id from >100 bytes to 64 bytes.

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

1 files changed, 2 insertions, 4 deletions

diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
index 6fee7e0b8931..6f28dd9bacb2 100644
--- a/fs/ceph/addr.c
+++ b/fs/ceph/addr.c
@@ -1758,9 +1758,7 @@ static int __ceph_pool_perm_get(struct ceph_inode_info *ci, u32 pool)
 	rd_req->r_flags = CEPH_OSD_FLAG_READ;
 	osd_req_op_init(rd_req, 0, CEPH_OSD_OP_STAT, 0);
 	rd_req->r_base_oloc.pool = pool;
-	snprintf(rd_req->r_base_oid.name, sizeof(rd_req->r_base_oid.name),
-		 "%llx.00000000", ci->i_vino.ino);
-	rd_req->r_base_oid.name_len = strlen(rd_req->r_base_oid.name);
+	ceph_oid_printf(&rd_req->r_base_oid, "%llx.00000000", ci->i_vino.ino);
 
 	err = ceph_osdc_alloc_messages(rd_req, GFP_NOFS);
 	if (err)
@@ -1777,7 +1775,7 @@ static int __ceph_pool_perm_get(struct ceph_inode_info *ci, u32 pool)
 			  CEPH_OSD_FLAG_ACK | CEPH_OSD_FLAG_ONDISK;
 	osd_req_op_init(wr_req, 0, CEPH_OSD_OP_CREATE, CEPH_OSD_OP_FLAG_EXCL);
 	wr_req->r_base_oloc.pool = pool;
-	wr_req->r_base_oid = rd_req->r_base_oid;
+	ceph_oid_copy(&wr_req->r_base_oid, &rd_req->r_base_oid);
 
 	err = ceph_osdc_alloc_messages(wr_req, GFP_NOFS);
 	if (err)