ceph: streamline request head structures in MDS client

The existence of the ceph_mds_request_head_old structure in the MDS
client code is no longer required due to improvements in handling
different MDS request header versions. This patch removes the now
redundant ceph_mds_request_head_old structure and replaces its usage
with the flexible and extensible ceph_mds_request_head structure.

Changes include:
- Modification of find_legacy_request_head to directly cast the
  pointer to ceph_mds_request_head_legacy without going through the
  old structure.
- Update sizeof calculations in create_request_message to use
  offsetofend for consistency and future-proofing, rather than
  referencing the old structure.
- Use of the structured ceph_mds_request_head directly instead of the
  old one.

Additionally, this consolidation normalizes the handling of
request_head_version v1 to align with versions v2 and v3, leading to
a more consistent and maintainable codebase.

These changes simplify the codebase and reduce potential confusion
stemming from the existence of an obsolete structure.

Signed-off-by: Liang Jie <liangjie@lixiang.com>
Reviewed-by: Viacheslav Dubeyko <Slava.Dubeyko@ibm.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index ae37f0e24c996ce81a2cbb6c0c45c5e59cf7a92c..921f08a27dd7af2ce9d8927d8be6765979e53a69 100644 (file)
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -2945,12 +2945,12 @@ static struct ceph_mds_request_head_legacy *
 find_legacy_request_head(void *p, u64 features)
 {
        bool legacy = !(features & CEPH_FEATURE_FS_BTIME);
-       struct ceph_mds_request_head_old *ohead;
+       struct ceph_mds_request_head *head;
 
        if (legacy)
                return (struct ceph_mds_request_head_legacy *)p;
-       ohead = (struct ceph_mds_request_head_old *)p;
-       return (struct ceph_mds_request_head_legacy *)&ohead->oldest_client_tid;
+       head = (struct ceph_mds_request_head *)p;
+       return (struct ceph_mds_request_head_legacy *)&head->oldest_client_tid;
 }
 
 /*
@@ -3020,7 +3020,7 @@ static struct ceph_msg *create_request_message(struct ceph_mds_session *session,
        if (legacy)
                len = sizeof(struct ceph_mds_request_head_legacy);
        else if (request_head_version == 1)
-               len = sizeof(struct ceph_mds_request_head_old);
+               len = offsetofend(struct ceph_mds_request_head, args);
        else if (request_head_version == 2)
                len = offsetofend(struct ceph_mds_request_head, ext_num_fwd);
        else
@@ -3104,11 +3104,11 @@ static struct ceph_msg *create_request_message(struct ceph_mds_session *session,
                msg->hdr.version = cpu_to_le16(3);
                p = msg->front.iov_base + sizeof(*lhead);
        } else if (request_head_version == 1) {
-               struct ceph_mds_request_head_old *ohead = msg->front.iov_base;
+               struct ceph_mds_request_head *nhead = msg->front.iov_base;
 
                msg->hdr.version = cpu_to_le16(4);
-               ohead->version = cpu_to_le16(1);
-               p = msg->front.iov_base + sizeof(*ohead);
+               nhead->version = cpu_to_le16(1);
+               p = msg->front.iov_base + offsetofend(struct ceph_mds_request_head, args);
        } else if (request_head_version == 2) {
                struct ceph_mds_request_head *nhead = msg->front.iov_base;
 
@@ -3265,7 +3265,7 @@ static int __prepare_send_request(struct ceph_mds_session *session,
         * so we limit to retry at most 256 times.
         */
        if (req->r_attempts) {
-              old_max_retry = sizeof_field(struct ceph_mds_request_head_old,
+              old_max_retry = sizeof_field(struct ceph_mds_request_head,
                                            num_retry);
               old_max_retry = 1 << (old_max_retry * BITS_PER_BYTE);
               if ((old_version && req->r_attempts >= old_max_retry) ||

diff --git a/include/linux/ceph/ceph_fs.h b/include/linux/ceph/ceph_fs.h
index 2d7d86f0290d98c1b60b0d1e52d6c0dbac0636a2..c7f2c63b3bc3fb3c6a1ec0d114fcaf9cd7489de3 100644 (file)
--- a/include/linux/ceph/ceph_fs.h
+++ b/include/linux/ceph/ceph_fs.h
@@ -504,20 +504,6 @@ struct ceph_mds_request_head_legacy {
 
 #define CEPH_MDS_REQUEST_HEAD_VERSION  3
 
-struct ceph_mds_request_head_old {
-       __le16 version;                /* struct version */
-       __le64 oldest_client_tid;
-       __le32 mdsmap_epoch;           /* on client */
-       __le32 flags;                  /* CEPH_MDS_FLAG_* */
-       __u8 num_retry, num_fwd;       /* count retry, fwd attempts */
-       __le16 num_releases;           /* # include cap/lease release records */
-       __le32 op;                     /* mds op code */
-       __le32 caller_uid, caller_gid;
-       __le64 ino;                    /* use this ino for openc, mkdir, mknod,
-                                         etc. (if replaying) */
-       union ceph_mds_request_args_ext args;
-} __attribute__ ((packed));
-
 struct ceph_mds_request_head {
        __le16 version;                /* struct version */
        __le64 oldest_client_tid;