[v9,03/12] ceph: handle idmapped mounts in create_request_message()

  From: Christian Brauner <brauner@kernel.org>

Inode operations that create a new filesystem object such as ->mknod,
->create, ->mkdir() and others don't take a {g,u}id argument explicitly.
Instead the caller's fs{g,u}id is used for the {g,u}id of the new
filesystem object.

In order to ensure that the correct {g,u}id is used map the caller's
fs{g,u}id for creation requests. This doesn't require complex changes.
It suffices to pass in the relevant idmapping recorded in the request
message. If this request message was triggered from an inode operation
that creates filesystem objects it will have passed down the relevant
idmaping. If this is a request message that was triggered from an inode
operation that doens't need to take idmappings into account the initial
idmapping is passed down which is an identity mapping.

This change uses a new cephfs protocol extension CEPHFS_FEATURE_HAS_OWNER_UIDGID
which adds two new fields (owner_{u,g}id) to the request head structure.
So, we need to ensure that MDS supports it otherwise we need to fail
any IO that comes through an idmapped mount because we can't process it
in a proper way. MDS server without such an extension will use caller_{u,g}id
fields to set a new inode owner UID/GID which is incorrect because caller_{u,g}id
values are unmapped. At the same time we can't map these fields with an
idmapping as it can break UID/GID-based permission checks logic on the
MDS side. This problem was described with a lot of details at [1], [2].

[1] https://lore.kernel.org/lkml/CAEivzxfw1fHO2TFA4dx3u23ZKK6Q+EThfzuibrhA3RKM=ZOYLg@mail.gmail.com/
[2] https://lore.kernel.org/all/20220104140414.155198-3-brauner@kernel.org/

Link: https://github.com/ceph/ceph/pull/52575
Link: https://tracker.ceph.com/issues/62217
Cc: Xiubo Li <xiubli@redhat.com>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: Ilya Dryomov <idryomov@gmail.com>
Cc: ceph-devel@vger.kernel.org
Co-Developed-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>
---
v7:
	- reworked to use two new fields for owner UID/GID (https://github.com/ceph/ceph/pull/52575)
v8:
	- properly handled case when old MDS used with new kernel client
---
 fs/ceph/mds_client.c         | 47 +++++++++++++++++++++++++++++++++---
 fs/ceph/mds_client.h         |  5 +++-
 include/linux/ceph/ceph_fs.h |  5 +++-
 3 files changed, 52 insertions(+), 5 deletions(-)
  

On Fri, Aug 04, 2023 at 10:48:49AM +0200, Alexander Mikhalitsyn wrote:
> From: Christian Brauner <brauner@kernel.org>
> 
> Inode operations that create a new filesystem object such as ->mknod,
> ->create, ->mkdir() and others don't take a {g,u}id argument explicitly.
> Instead the caller's fs{g,u}id is used for the {g,u}id of the new
> filesystem object.
> 
> In order to ensure that the correct {g,u}id is used map the caller's
> fs{g,u}id for creation requests. This doesn't require complex changes.
> It suffices to pass in the relevant idmapping recorded in the request
> message. If this request message was triggered from an inode operation
> that creates filesystem objects it will have passed down the relevant
> idmaping. If this is a request message that was triggered from an inode
> operation that doens't need to take idmappings into account the initial
> idmapping is passed down which is an identity mapping.
> 
> This change uses a new cephfs protocol extension CEPHFS_FEATURE_HAS_OWNER_UIDGID
> which adds two new fields (owner_{u,g}id) to the request head structure.
> So, we need to ensure that MDS supports it otherwise we need to fail
> any IO that comes through an idmapped mount because we can't process it
> in a proper way. MDS server without such an extension will use caller_{u,g}id
> fields to set a new inode owner UID/GID which is incorrect because caller_{u,g}id
> values are unmapped. At the same time we can't map these fields with an
> idmapping as it can break UID/GID-based permission checks logic on the
> MDS side. This problem was described with a lot of details at [1], [2].
> 
> [1] https://lore.kernel.org/lkml/CAEivzxfw1fHO2TFA4dx3u23ZKK6Q+EThfzuibrhA3RKM=ZOYLg@mail.gmail.com/
> [2] https://lore.kernel.org/all/20220104140414.155198-3-brauner@kernel.org/
> 
> Link: https://github.com/ceph/ceph/pull/52575
> Link: https://tracker.ceph.com/issues/62217
> Cc: Xiubo Li <xiubli@redhat.com>
> Cc: Jeff Layton <jlayton@kernel.org>
> Cc: Ilya Dryomov <idryomov@gmail.com>
> Cc: ceph-devel@vger.kernel.org
> Co-Developed-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>
> Signed-off-by: Christian Brauner <brauner@kernel.org>
> Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>
> ---

I like the new extension,
Acked-by: Christian Brauner <brauner@kernel.org>
  

Hi Alexander,

kernel test robot noticed the following build warnings:

[auto build test WARNING on ceph-client/testing]
[cannot apply to ceph-client/for-linus brauner-vfs/vfs.all linus/master vfs-idmapping/for-next v6.5-rc4 next-20230804]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Alexander-Mikhalitsyn/fs-export-mnt_idmap_get-mnt_idmap_put/20230804-165330
base:   https://github.com/ceph/ceph-client.git testing
patch link:    https://lore.kernel.org/r/20230804084858.126104-4-aleksandr.mikhalitsyn%40canonical.com
patch subject: [PATCH v9 03/12] ceph: handle idmapped mounts in create_request_message()
config: um-randconfig-r091-20230730 (https://download.01.org/0day-ci/archive/20230805/202308050925.ifGg1BUH-lkp@intel.com/config)
compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
reproduce: (https://download.01.org/0day-ci/archive/20230805/202308050925.ifGg1BUH-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202308050925.ifGg1BUH-lkp@intel.com/

sparse warnings: (new ones prefixed by >>)
>> fs/ceph/mds_client.c:3082:35: sparse: sparse: incorrect type in assignment (different base types) @@     expected restricted __le32 [usertype] struct_len @@     got unsigned long @@
   fs/ceph/mds_client.c:3082:35: sparse:     expected restricted __le32 [usertype] struct_len
   fs/ceph/mds_client.c:3082:35: sparse:     got unsigned long

vim +3082 fs/ceph/mds_client.c

  2927	
  2928	/*
  2929	 * called under mdsc->mutex
  2930	 */
  2931	static struct ceph_msg *create_request_message(struct ceph_mds_session *session,
  2932						       struct ceph_mds_request *req,
  2933						       bool drop_cap_releases)
  2934	{
  2935		int mds = session->s_mds;
  2936		struct ceph_mds_client *mdsc = session->s_mdsc;
  2937		struct ceph_client *cl = mdsc->fsc->client;
  2938		struct ceph_msg *msg;
  2939		struct ceph_mds_request_head_legacy *lhead;
  2940		const char *path1 = NULL;
  2941		const char *path2 = NULL;
  2942		u64 ino1 = 0, ino2 = 0;
  2943		int pathlen1 = 0, pathlen2 = 0;
  2944		bool freepath1 = false, freepath2 = false;
  2945		struct dentry *old_dentry = NULL;
  2946		int len;
  2947		u16 releases;
  2948		void *p, *end;
  2949		int ret;
  2950		bool legacy = !(session->s_con.peer_features & CEPH_FEATURE_FS_BTIME);
  2951		u16 request_head_version = mds_supported_head_version(session);
  2952	
  2953		ret = set_request_path_attr(mdsc, req->r_inode, req->r_dentry,
  2954				      req->r_parent, req->r_path1, req->r_ino1.ino,
  2955				      &path1, &pathlen1, &ino1, &freepath1,
  2956				      test_bit(CEPH_MDS_R_PARENT_LOCKED,
  2957						&req->r_req_flags));
  2958		if (ret < 0) {
  2959			msg = ERR_PTR(ret);
  2960			goto out;
  2961		}
  2962	
  2963		/* If r_old_dentry is set, then assume that its parent is locked */
  2964		if (req->r_old_dentry &&
  2965		    !(req->r_old_dentry->d_flags & DCACHE_DISCONNECTED))
  2966			old_dentry = req->r_old_dentry;
  2967		ret = set_request_path_attr(mdsc, NULL, old_dentry,
  2968				      req->r_old_dentry_dir,
  2969				      req->r_path2, req->r_ino2.ino,
  2970				      &path2, &pathlen2, &ino2, &freepath2, true);
  2971		if (ret < 0) {
  2972			msg = ERR_PTR(ret);
  2973			goto out_free1;
  2974		}
  2975	
  2976		req->r_altname = get_fscrypt_altname(req, &req->r_altname_len);
  2977		if (IS_ERR(req->r_altname)) {
  2978			msg = ERR_CAST(req->r_altname);
  2979			req->r_altname = NULL;
  2980			goto out_free2;
  2981		}
  2982	
  2983		/*
  2984		 * For old cephs without supporting the 32bit retry/fwd feature
  2985		 * it will copy the raw memories directly when decoding the
  2986		 * requests. While new cephs will decode the head depending the
  2987		 * version member, so we need to make sure it will be compatible
  2988		 * with them both.
  2989		 */
  2990		if (legacy)
  2991			len = sizeof(struct ceph_mds_request_head_legacy);
  2992		else if (request_head_version == 1)
  2993			len = sizeof(struct ceph_mds_request_head_old);
  2994		else if (request_head_version == 2)
  2995			len = offsetofend(struct ceph_mds_request_head, ext_num_fwd);
  2996		else
  2997			len = sizeof(struct ceph_mds_request_head);
  2998	
  2999		/* filepaths */
  3000		len += 2 * (1 + sizeof(u32) + sizeof(u64));
  3001		len += pathlen1 + pathlen2;
  3002	
  3003		/* cap releases */
  3004		len += sizeof(struct ceph_mds_request_release) *
  3005			(!!req->r_inode_drop + !!req->r_dentry_drop +
  3006			 !!req->r_old_inode_drop + !!req->r_old_dentry_drop);
  3007	
  3008		if (req->r_dentry_drop)
  3009			len += pathlen1;
  3010		if (req->r_old_dentry_drop)
  3011			len += pathlen2;
  3012	
  3013		/* MClientRequest tail */
  3014	
  3015		/* req->r_stamp */
  3016		len += sizeof(struct ceph_timespec);
  3017	
  3018		/* gid list */
  3019		len += sizeof(u32) + (sizeof(u64) * req->r_cred->group_info->ngroups);
  3020	
  3021		/* alternate name */
  3022		len += sizeof(u32) + req->r_altname_len;
  3023	
  3024		/* fscrypt_auth */
  3025		len += sizeof(u32); // fscrypt_auth
  3026		if (req->r_fscrypt_auth)
  3027			len += ceph_fscrypt_auth_len(req->r_fscrypt_auth);
  3028	
  3029		/* fscrypt_file */
  3030		len += sizeof(u32);
  3031		if (test_bit(CEPH_MDS_R_FSCRYPT_FILE, &req->r_req_flags))
  3032			len += sizeof(__le64);
  3033	
  3034		msg = ceph_msg_new2(CEPH_MSG_CLIENT_REQUEST, len, 1, GFP_NOFS, false);
  3035		if (!msg) {
  3036			msg = ERR_PTR(-ENOMEM);
  3037			goto out_free2;
  3038		}
  3039	
  3040		msg->hdr.tid = cpu_to_le64(req->r_tid);
  3041	
  3042		lhead = find_legacy_request_head(msg->front.iov_base,
  3043						 session->s_con.peer_features);
  3044	
  3045		if ((req->r_mnt_idmap != &nop_mnt_idmap) &&
  3046		    !test_bit(CEPHFS_FEATURE_HAS_OWNER_UIDGID, &session->s_features)) {
  3047			pr_err_ratelimited_client(cl,
  3048				"idmapped mount is used and CEPHFS_FEATURE_HAS_OWNER_UIDGID"
  3049				" is not supported by MDS. Fail request with -EIO.\n");
  3050	
  3051			ret = -EIO;
  3052			goto out_err;
  3053		}
  3054	
  3055		/*
  3056		 * The ceph_mds_request_head_legacy didn't contain a version field, and
  3057		 * one was added when we moved the message version from 3->4.
  3058		 */
  3059		if (legacy) {
  3060			msg->hdr.version = cpu_to_le16(3);
  3061			p = msg->front.iov_base + sizeof(*lhead);
  3062		} else if (request_head_version == 1) {
  3063			struct ceph_mds_request_head_old *ohead = msg->front.iov_base;
  3064	
  3065			msg->hdr.version = cpu_to_le16(4);
  3066			ohead->version = cpu_to_le16(1);
  3067			p = msg->front.iov_base + sizeof(*ohead);
  3068		} else if (request_head_version == 2) {
  3069			struct ceph_mds_request_head *nhead = msg->front.iov_base;
  3070	
  3071			msg->hdr.version = cpu_to_le16(6);
  3072			nhead->version = cpu_to_le16(2);
  3073	
  3074			p = msg->front.iov_base + offsetofend(struct ceph_mds_request_head, ext_num_fwd);
  3075		} else {
  3076			struct ceph_mds_request_head *nhead = msg->front.iov_base;
  3077			kuid_t owner_fsuid;
  3078			kgid_t owner_fsgid;
  3079	
  3080			msg->hdr.version = cpu_to_le16(6);
  3081			nhead->version = cpu_to_le16(CEPH_MDS_REQUEST_HEAD_VERSION);
> 3082			nhead->struct_len = sizeof(struct ceph_mds_request_head);
  3083	
  3084			owner_fsuid = from_vfsuid(req->r_mnt_idmap, &init_user_ns,
  3085						  VFSUIDT_INIT(req->r_cred->fsuid));
  3086			owner_fsgid = from_vfsgid(req->r_mnt_idmap, &init_user_ns,
  3087						  VFSGIDT_INIT(req->r_cred->fsgid));
  3088			nhead->owner_uid = cpu_to_le32(from_kuid(&init_user_ns, owner_fsuid));
  3089			nhead->owner_gid = cpu_to_le32(from_kgid(&init_user_ns, owner_fsgid));
  3090			p = msg->front.iov_base + sizeof(*nhead);
  3091		}
  3092	
  3093		end = msg->front.iov_base + msg->front.iov_len;
  3094	
  3095		lhead->mdsmap_epoch = cpu_to_le32(mdsc->mdsmap->m_epoch);
  3096		lhead->op = cpu_to_le32(req->r_op);
  3097		lhead->caller_uid = cpu_to_le32(from_kuid(&init_user_ns,
  3098							  req->r_cred->fsuid));
  3099		lhead->caller_gid = cpu_to_le32(from_kgid(&init_user_ns,
  3100							  req->r_cred->fsgid));
  3101		lhead->ino = cpu_to_le64(req->r_deleg_ino);
  3102		lhead->args = req->r_args;
  3103	
  3104		ceph_encode_filepath(&p, end, ino1, path1);
  3105		ceph_encode_filepath(&p, end, ino2, path2);
  3106	
  3107		/* make note of release offset, in case we need to replay */
  3108		req->r_request_release_offset = p - msg->front.iov_base;
  3109	
  3110		/* cap releases */
  3111		releases = 0;
  3112		if (req->r_inode_drop)
  3113			releases += ceph_encode_inode_release(&p,
  3114			      req->r_inode ? req->r_inode : d_inode(req->r_dentry),
  3115			      mds, req->r_inode_drop, req->r_inode_unless,
  3116			      req->r_op == CEPH_MDS_OP_READDIR);
  3117		if (req->r_dentry_drop) {
  3118			ret = ceph_encode_dentry_release(&p, req->r_dentry,
  3119					req->r_parent, mds, req->r_dentry_drop,
  3120					req->r_dentry_unless);
  3121			if (ret < 0)
  3122				goto out_err;
  3123			releases += ret;
  3124		}
  3125		if (req->r_old_dentry_drop) {
  3126			ret = ceph_encode_dentry_release(&p, req->r_old_dentry,
  3127					req->r_old_dentry_dir, mds,
  3128					req->r_old_dentry_drop,
  3129					req->r_old_dentry_unless);
  3130			if (ret < 0)
  3131				goto out_err;
  3132			releases += ret;
  3133		}
  3134		if (req->r_old_inode_drop)
  3135			releases += ceph_encode_inode_release(&p,
  3136			      d_inode(req->r_old_dentry),
  3137			      mds, req->r_old_inode_drop, req->r_old_inode_unless, 0);
  3138	
  3139		if (drop_cap_releases) {
  3140			releases = 0;
  3141			p = msg->front.iov_base + req->r_request_release_offset;
  3142		}
  3143	
  3144		lhead->num_releases = cpu_to_le16(releases);
  3145	
  3146		encode_mclientrequest_tail(&p, req);
  3147	
  3148		if (WARN_ON_ONCE(p > end)) {
  3149			ceph_msg_put(msg);
  3150			msg = ERR_PTR(-ERANGE);
  3151			goto out_free2;
  3152		}
  3153	
  3154		msg->front.iov_len = p - msg->front.iov_base;
  3155		msg->hdr.front_len = cpu_to_le32(msg->front.iov_len);
  3156	
  3157		if (req->r_pagelist) {
  3158			struct ceph_pagelist *pagelist = req->r_pagelist;
  3159			ceph_msg_data_add_pagelist(msg, pagelist);
  3160			msg->hdr.data_len = cpu_to_le32(pagelist->length);
  3161		} else {
  3162			msg->hdr.data_len = 0;
  3163		}
  3164	
  3165		msg->hdr.data_off = cpu_to_le16(0);
  3166	
  3167	out_free2:
  3168		if (freepath2)
  3169			ceph_mdsc_free_path((char *)path2, pathlen2);
  3170	out_free1:
  3171		if (freepath1)
  3172			ceph_mdsc_free_path((char *)path1, pathlen1);
  3173	out:
  3174		return msg;
  3175	out_err:
  3176		ceph_msg_put(msg);
  3177		msg = ERR_PTR(ret);
  3178		goto out_free2;
  3179	}
  3180
  

On Sat, Aug 5, 2023 at 3:56 AM kernel test robot <lkp@intel.com> wrote:
>
> Hi Alexander,
>
> kernel test robot noticed the following build warnings:
>
> [auto build test WARNING on ceph-client/testing]
> [cannot apply to ceph-client/for-linus brauner-vfs/vfs.all linus/master vfs-idmapping/for-next v6.5-rc4 next-20230804]
> [If your patch is applied to the wrong git tree, kindly drop us a note.
> And when submitting patch, we suggest to use '--base' as documented in
> https://git-scm.com/docs/git-format-patch#_base_tree_information]
>
> url:    https://github.com/intel-lab-lkp/linux/commits/Alexander-Mikhalitsyn/fs-export-mnt_idmap_get-mnt_idmap_put/20230804-165330
> base:   https://github.com/ceph/ceph-client.git testing
> patch link:    https://lore.kernel.org/r/20230804084858.126104-4-aleksandr.mikhalitsyn%40canonical.com
> patch subject: [PATCH v9 03/12] ceph: handle idmapped mounts in create_request_message()
> config: um-randconfig-r091-20230730 (https://download.01.org/0day-ci/archive/20230805/202308050925.ifGg1BUH-lkp@intel.com/config)
> compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
> reproduce: (https://download.01.org/0day-ci/archive/20230805/202308050925.ifGg1BUH-lkp@intel.com/reproduce)
>
> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> the same patch/commit), kindly add following tags
> | Reported-by: kernel test robot <lkp@intel.com>
> | Closes: https://lore.kernel.org/oe-kbuild-all/202308050925.ifGg1BUH-lkp@intel.com/
>
> sparse warnings: (new ones prefixed by >>)
> >> fs/ceph/mds_client.c:3082:35: sparse: sparse: incorrect type in assignment (different base types) @@     expected restricted __le32 [usertype] struct_len @@     got unsigned long @@
>    fs/ceph/mds_client.c:3082:35: sparse:     expected restricted __le32 [usertype] struct_len
>    fs/ceph/mds_client.c:3082:35: sparse:     got unsigned long
>
> vim +3082 fs/ceph/mds_client.c
>
>   2927
>   2928  /*
>   2929   * called under mdsc->mutex
>   2930   */
>   2931  static struct ceph_msg *create_request_message(struct ceph_mds_session *session,
>   2932                                                 struct ceph_mds_request *req,
>   2933                                                 bool drop_cap_releases)
>   2934  {
>   2935          int mds = session->s_mds;
>   2936          struct ceph_mds_client *mdsc = session->s_mdsc;
>   2937          struct ceph_client *cl = mdsc->fsc->client;
>   2938          struct ceph_msg *msg;
>   2939          struct ceph_mds_request_head_legacy *lhead;
>   2940          const char *path1 = NULL;
>   2941          const char *path2 = NULL;
>   2942          u64 ino1 = 0, ino2 = 0;
>   2943          int pathlen1 = 0, pathlen2 = 0;
>   2944          bool freepath1 = false, freepath2 = false;
>   2945          struct dentry *old_dentry = NULL;
>   2946          int len;
>   2947          u16 releases;
>   2948          void *p, *end;
>   2949          int ret;
>   2950          bool legacy = !(session->s_con.peer_features & CEPH_FEATURE_FS_BTIME);
>   2951          u16 request_head_version = mds_supported_head_version(session);
>   2952
>   2953          ret = set_request_path_attr(mdsc, req->r_inode, req->r_dentry,
>   2954                                req->r_parent, req->r_path1, req->r_ino1.ino,
>   2955                                &path1, &pathlen1, &ino1, &freepath1,
>   2956                                test_bit(CEPH_MDS_R_PARENT_LOCKED,
>   2957                                          &req->r_req_flags));
>   2958          if (ret < 0) {
>   2959                  msg = ERR_PTR(ret);
>   2960                  goto out;
>   2961          }
>   2962
>   2963          /* If r_old_dentry is set, then assume that its parent is locked */
>   2964          if (req->r_old_dentry &&
>   2965              !(req->r_old_dentry->d_flags & DCACHE_DISCONNECTED))
>   2966                  old_dentry = req->r_old_dentry;
>   2967          ret = set_request_path_attr(mdsc, NULL, old_dentry,
>   2968                                req->r_old_dentry_dir,
>   2969                                req->r_path2, req->r_ino2.ino,
>   2970                                &path2, &pathlen2, &ino2, &freepath2, true);
>   2971          if (ret < 0) {
>   2972                  msg = ERR_PTR(ret);
>   2973                  goto out_free1;
>   2974          }
>   2975
>   2976          req->r_altname = get_fscrypt_altname(req, &req->r_altname_len);
>   2977          if (IS_ERR(req->r_altname)) {
>   2978                  msg = ERR_CAST(req->r_altname);
>   2979                  req->r_altname = NULL;
>   2980                  goto out_free2;
>   2981          }
>   2982
>   2983          /*
>   2984           * For old cephs without supporting the 32bit retry/fwd feature
>   2985           * it will copy the raw memories directly when decoding the
>   2986           * requests. While new cephs will decode the head depending the
>   2987           * version member, so we need to make sure it will be compatible
>   2988           * with them both.
>   2989           */
>   2990          if (legacy)
>   2991                  len = sizeof(struct ceph_mds_request_head_legacy);
>   2992          else if (request_head_version == 1)
>   2993                  len = sizeof(struct ceph_mds_request_head_old);
>   2994          else if (request_head_version == 2)
>   2995                  len = offsetofend(struct ceph_mds_request_head, ext_num_fwd);
>   2996          else
>   2997                  len = sizeof(struct ceph_mds_request_head);
>   2998
>   2999          /* filepaths */
>   3000          len += 2 * (1 + sizeof(u32) + sizeof(u64));
>   3001          len += pathlen1 + pathlen2;
>   3002
>   3003          /* cap releases */
>   3004          len += sizeof(struct ceph_mds_request_release) *
>   3005                  (!!req->r_inode_drop + !!req->r_dentry_drop +
>   3006                   !!req->r_old_inode_drop + !!req->r_old_dentry_drop);
>   3007
>   3008          if (req->r_dentry_drop)
>   3009                  len += pathlen1;
>   3010          if (req->r_old_dentry_drop)
>   3011                  len += pathlen2;
>   3012
>   3013          /* MClientRequest tail */
>   3014
>   3015          /* req->r_stamp */
>   3016          len += sizeof(struct ceph_timespec);
>   3017
>   3018          /* gid list */
>   3019          len += sizeof(u32) + (sizeof(u64) * req->r_cred->group_info->ngroups);
>   3020
>   3021          /* alternate name */
>   3022          len += sizeof(u32) + req->r_altname_len;
>   3023
>   3024          /* fscrypt_auth */
>   3025          len += sizeof(u32); // fscrypt_auth
>   3026          if (req->r_fscrypt_auth)
>   3027                  len += ceph_fscrypt_auth_len(req->r_fscrypt_auth);
>   3028
>   3029          /* fscrypt_file */
>   3030          len += sizeof(u32);
>   3031          if (test_bit(CEPH_MDS_R_FSCRYPT_FILE, &req->r_req_flags))
>   3032                  len += sizeof(__le64);
>   3033
>   3034          msg = ceph_msg_new2(CEPH_MSG_CLIENT_REQUEST, len, 1, GFP_NOFS, false);
>   3035          if (!msg) {
>   3036                  msg = ERR_PTR(-ENOMEM);
>   3037                  goto out_free2;
>   3038          }
>   3039
>   3040          msg->hdr.tid = cpu_to_le64(req->r_tid);
>   3041
>   3042          lhead = find_legacy_request_head(msg->front.iov_base,
>   3043                                           session->s_con.peer_features);
>   3044
>   3045          if ((req->r_mnt_idmap != &nop_mnt_idmap) &&
>   3046              !test_bit(CEPHFS_FEATURE_HAS_OWNER_UIDGID, &session->s_features)) {
>   3047                  pr_err_ratelimited_client(cl,
>   3048                          "idmapped mount is used and CEPHFS_FEATURE_HAS_OWNER_UIDGID"
>   3049                          " is not supported by MDS. Fail request with -EIO.\n");
>   3050
>   3051                  ret = -EIO;
>   3052                  goto out_err;
>   3053          }
>   3054
>   3055          /*
>   3056           * The ceph_mds_request_head_legacy didn't contain a version field, and
>   3057           * one was added when we moved the message version from 3->4.
>   3058           */
>   3059          if (legacy) {
>   3060                  msg->hdr.version = cpu_to_le16(3);
>   3061                  p = msg->front.iov_base + sizeof(*lhead);
>   3062          } else if (request_head_version == 1) {
>   3063                  struct ceph_mds_request_head_old *ohead = msg->front.iov_base;
>   3064
>   3065                  msg->hdr.version = cpu_to_le16(4);
>   3066                  ohead->version = cpu_to_le16(1);
>   3067                  p = msg->front.iov_base + sizeof(*ohead);
>   3068          } else if (request_head_version == 2) {
>   3069                  struct ceph_mds_request_head *nhead = msg->front.iov_base;
>   3070
>   3071                  msg->hdr.version = cpu_to_le16(6);
>   3072                  nhead->version = cpu_to_le16(2);
>   3073
>   3074                  p = msg->front.iov_base + offsetofend(struct ceph_mds_request_head, ext_num_fwd);
>   3075          } else {
>   3076                  struct ceph_mds_request_head *nhead = msg->front.iov_base;
>   3077                  kuid_t owner_fsuid;
>   3078                  kgid_t owner_fsgid;
>   3079
>   3080                  msg->hdr.version = cpu_to_le16(6);
>   3081                  nhead->version = cpu_to_le16(CEPH_MDS_REQUEST_HEAD_VERSION);
> > 3082                  nhead->struct_len = sizeof(struct ceph_mds_request_head);

should be
nhead->struct_len = cpu_to_le32(sizeof(struct ceph_mds_request_head));

Fixed and pushed https://github.com/mihalicyn/linux/commits/fs.idmapped.ceph


>   3083
>   3084                  owner_fsuid = from_vfsuid(req->r_mnt_idmap, &init_user_ns,
>   3085                                            VFSUIDT_INIT(req->r_cred->fsuid));
>   3086                  owner_fsgid = from_vfsgid(req->r_mnt_idmap, &init_user_ns,
>   3087                                            VFSGIDT_INIT(req->r_cred->fsgid));
>   3088                  nhead->owner_uid = cpu_to_le32(from_kuid(&init_user_ns, owner_fsuid));
>   3089                  nhead->owner_gid = cpu_to_le32(from_kgid(&init_user_ns, owner_fsgid));
>   3090                  p = msg->front.iov_base + sizeof(*nhead);
>   3091          }
>   3092
>   3093          end = msg->front.iov_base + msg->front.iov_len;
>   3094
>   3095          lhead->mdsmap_epoch = cpu_to_le32(mdsc->mdsmap->m_epoch);
>   3096          lhead->op = cpu_to_le32(req->r_op);
>   3097          lhead->caller_uid = cpu_to_le32(from_kuid(&init_user_ns,
>   3098                                                    req->r_cred->fsuid));
>   3099          lhead->caller_gid = cpu_to_le32(from_kgid(&init_user_ns,
>   3100                                                    req->r_cred->fsgid));
>   3101          lhead->ino = cpu_to_le64(req->r_deleg_ino);
>   3102          lhead->args = req->r_args;
>   3103
>   3104          ceph_encode_filepath(&p, end, ino1, path1);
>   3105          ceph_encode_filepath(&p, end, ino2, path2);
>   3106
>   3107          /* make note of release offset, in case we need to replay */
>   3108          req->r_request_release_offset = p - msg->front.iov_base;
>   3109
>   3110          /* cap releases */
>   3111          releases = 0;
>   3112          if (req->r_inode_drop)
>   3113                  releases += ceph_encode_inode_release(&p,
>   3114                        req->r_inode ? req->r_inode : d_inode(req->r_dentry),
>   3115                        mds, req->r_inode_drop, req->r_inode_unless,
>   3116                        req->r_op == CEPH_MDS_OP_READDIR);
>   3117          if (req->r_dentry_drop) {
>   3118                  ret = ceph_encode_dentry_release(&p, req->r_dentry,
>   3119                                  req->r_parent, mds, req->r_dentry_drop,
>   3120                                  req->r_dentry_unless);
>   3121                  if (ret < 0)
>   3122                          goto out_err;
>   3123                  releases += ret;
>   3124          }
>   3125          if (req->r_old_dentry_drop) {
>   3126                  ret = ceph_encode_dentry_release(&p, req->r_old_dentry,
>   3127                                  req->r_old_dentry_dir, mds,
>   3128                                  req->r_old_dentry_drop,
>   3129                                  req->r_old_dentry_unless);
>   3130                  if (ret < 0)
>   3131                          goto out_err;
>   3132                  releases += ret;
>   3133          }
>   3134          if (req->r_old_inode_drop)
>   3135                  releases += ceph_encode_inode_release(&p,
>   3136                        d_inode(req->r_old_dentry),
>   3137                        mds, req->r_old_inode_drop, req->r_old_inode_unless, 0);
>   3138
>   3139          if (drop_cap_releases) {
>   3140                  releases = 0;
>   3141                  p = msg->front.iov_base + req->r_request_release_offset;
>   3142          }
>   3143
>   3144          lhead->num_releases = cpu_to_le16(releases);
>   3145
>   3146          encode_mclientrequest_tail(&p, req);
>   3147
>   3148          if (WARN_ON_ONCE(p > end)) {
>   3149                  ceph_msg_put(msg);
>   3150                  msg = ERR_PTR(-ERANGE);
>   3151                  goto out_free2;
>   3152          }
>   3153
>   3154          msg->front.iov_len = p - msg->front.iov_base;
>   3155          msg->hdr.front_len = cpu_to_le32(msg->front.iov_len);
>   3156
>   3157          if (req->r_pagelist) {
>   3158                  struct ceph_pagelist *pagelist = req->r_pagelist;
>   3159                  ceph_msg_data_add_pagelist(msg, pagelist);
>   3160                  msg->hdr.data_len = cpu_to_le32(pagelist->length);
>   3161          } else {
>   3162                  msg->hdr.data_len = 0;
>   3163          }
>   3164
>   3165          msg->hdr.data_off = cpu_to_le16(0);
>   3166
>   3167  out_free2:
>   3168          if (freepath2)
>   3169                  ceph_mdsc_free_path((char *)path2, pathlen2);
>   3170  out_free1:
>   3171          if (freepath1)
>   3172                  ceph_mdsc_free_path((char *)path1, pathlen1);
>   3173  out:
>   3174          return msg;
>   3175  out_err:
>   3176          ceph_msg_put(msg);
>   3177          msg = ERR_PTR(ret);
>   3178          goto out_free2;
>   3179  }
>   3180
>
> --
> 0-DAY CI Kernel Test Service
> https://github.com/intel/lkp-tests/wiki
  

On 8/4/23 16:48, Alexander Mikhalitsyn wrote:
> From: Christian Brauner <brauner@kernel.org>
>
> Inode operations that create a new filesystem object such as ->mknod,
> ->create, ->mkdir() and others don't take a {g,u}id argument explicitly.
> Instead the caller's fs{g,u}id is used for the {g,u}id of the new
> filesystem object.
>
> In order to ensure that the correct {g,u}id is used map the caller's
> fs{g,u}id for creation requests. This doesn't require complex changes.
> It suffices to pass in the relevant idmapping recorded in the request
> message. If this request message was triggered from an inode operation
> that creates filesystem objects it will have passed down the relevant
> idmaping. If this is a request message that was triggered from an inode
> operation that doens't need to take idmappings into account the initial
> idmapping is passed down which is an identity mapping.
>
> This change uses a new cephfs protocol extension CEPHFS_FEATURE_HAS_OWNER_UIDGID
> which adds two new fields (owner_{u,g}id) to the request head structure.
> So, we need to ensure that MDS supports it otherwise we need to fail
> any IO that comes through an idmapped mount because we can't process it
> in a proper way. MDS server without such an extension will use caller_{u,g}id
> fields to set a new inode owner UID/GID which is incorrect because caller_{u,g}id
> values are unmapped. At the same time we can't map these fields with an
> idmapping as it can break UID/GID-based permission checks logic on the
> MDS side. This problem was described with a lot of details at [1], [2].
>
> [1] https://lore.kernel.org/lkml/CAEivzxfw1fHO2TFA4dx3u23ZKK6Q+EThfzuibrhA3RKM=ZOYLg@mail.gmail.com/
> [2] https://lore.kernel.org/all/20220104140414.155198-3-brauner@kernel.org/
>
> Link: https://github.com/ceph/ceph/pull/52575
> Link: https://tracker.ceph.com/issues/62217
> Cc: Xiubo Li <xiubli@redhat.com>
> Cc: Jeff Layton <jlayton@kernel.org>
> Cc: Ilya Dryomov <idryomov@gmail.com>
> Cc: ceph-devel@vger.kernel.org
> Co-Developed-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>
> Signed-off-by: Christian Brauner <brauner@kernel.org>
> Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>
> ---
> v7:
> 	- reworked to use two new fields for owner UID/GID (https://github.com/ceph/ceph/pull/52575)
> v8:
> 	- properly handled case when old MDS used with new kernel client
> ---
>   fs/ceph/mds_client.c         | 47 +++++++++++++++++++++++++++++++++---
>   fs/ceph/mds_client.h         |  5 +++-
>   include/linux/ceph/ceph_fs.h |  5 +++-
>   3 files changed, 52 insertions(+), 5 deletions(-)
>
> diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
> index 8829f55103da..41e4bf3811c4 100644
> --- a/fs/ceph/mds_client.c
> +++ b/fs/ceph/mds_client.c
> @@ -2902,6 +2902,17 @@ static void encode_mclientrequest_tail(void **p, const struct ceph_mds_request *
>   	}
>   }
>   
> +static inline u16 mds_supported_head_version(struct ceph_mds_session *session)
> +{
> +	if (!test_bit(CEPHFS_FEATURE_32BITS_RETRY_FWD, &session->s_features))
> +		return 1;
> +
> +	if (!test_bit(CEPHFS_FEATURE_HAS_OWNER_UIDGID, &session->s_features))
> +		return 2;
> +
> +	return CEPH_MDS_REQUEST_HEAD_VERSION;
> +}
> +
>   static struct ceph_mds_request_head_legacy *
>   find_legacy_request_head(void *p, u64 features)
>   {
> @@ -2923,6 +2934,7 @@ static struct ceph_msg *create_request_message(struct ceph_mds_session *session,
>   {
>   	int mds = session->s_mds;
>   	struct ceph_mds_client *mdsc = session->s_mdsc;
> +	struct ceph_client *cl = mdsc->fsc->client;
>   	struct ceph_msg *msg;
>   	struct ceph_mds_request_head_legacy *lhead;
>   	const char *path1 = NULL;
> @@ -2936,7 +2948,7 @@ static struct ceph_msg *create_request_message(struct ceph_mds_session *session,
>   	void *p, *end;
>   	int ret;
>   	bool legacy = !(session->s_con.peer_features & CEPH_FEATURE_FS_BTIME);
> -	bool old_version = !test_bit(CEPHFS_FEATURE_32BITS_RETRY_FWD, &session->s_features);
> +	u16 request_head_version = mds_supported_head_version(session);
>   
>   	ret = set_request_path_attr(mdsc, req->r_inode, req->r_dentry,
>   			      req->r_parent, req->r_path1, req->r_ino1.ino,
> @@ -2977,8 +2989,10 @@ static struct ceph_msg *create_request_message(struct ceph_mds_session *session,
>   	 */
>   	if (legacy)
>   		len = sizeof(struct ceph_mds_request_head_legacy);
> -	else if (old_version)
> +	else if (request_head_version == 1)
>   		len = sizeof(struct ceph_mds_request_head_old);
> +	else if (request_head_version == 2)
> +		len = offsetofend(struct ceph_mds_request_head, ext_num_fwd);
>   	else
>   		len = sizeof(struct ceph_mds_request_head);
>   
> @@ -3028,6 +3042,16 @@ static struct ceph_msg *create_request_message(struct ceph_mds_session *session,
>   	lhead = find_legacy_request_head(msg->front.iov_base,
>   					 session->s_con.peer_features);
>   
> +	if ((req->r_mnt_idmap != &nop_mnt_idmap) &&
> +	    !test_bit(CEPHFS_FEATURE_HAS_OWNER_UIDGID, &session->s_features)) {
> +		pr_err_ratelimited_client(cl,
> +			"idmapped mount is used and CEPHFS_FEATURE_HAS_OWNER_UIDGID"
> +			" is not supported by MDS. Fail request with -EIO.\n");
> +
> +		ret = -EIO;
> +		goto out_err;
> +	}
> +
>   	/*
>   	 * The ceph_mds_request_head_legacy didn't contain a version field, and
>   	 * one was added when we moved the message version from 3->4.
> @@ -3035,17 +3059,34 @@ static struct ceph_msg *create_request_message(struct ceph_mds_session *session,
>   	if (legacy) {
>   		msg->hdr.version = cpu_to_le16(3);
>   		p = msg->front.iov_base + sizeof(*lhead);
> -	} else if (old_version) {
> +	} else if (request_head_version == 1) {
>   		struct ceph_mds_request_head_old *ohead = msg->front.iov_base;
>   
>   		msg->hdr.version = cpu_to_le16(4);
>   		ohead->version = cpu_to_le16(1);
>   		p = msg->front.iov_base + sizeof(*ohead);
> +	} else if (request_head_version == 2) {
> +		struct ceph_mds_request_head *nhead = msg->front.iov_base;
> +
> +		msg->hdr.version = cpu_to_le16(6);
> +		nhead->version = cpu_to_le16(2);
> +
> +		p = msg->front.iov_base + offsetofend(struct ceph_mds_request_head, ext_num_fwd);
>   	} else {
>   		struct ceph_mds_request_head *nhead = msg->front.iov_base;
> +		kuid_t owner_fsuid;
> +		kgid_t owner_fsgid;
>   
>   		msg->hdr.version = cpu_to_le16(6);
>   		nhead->version = cpu_to_le16(CEPH_MDS_REQUEST_HEAD_VERSION);
> +		nhead->struct_len = sizeof(struct ceph_mds_request_head);
> +
> +		owner_fsuid = from_vfsuid(req->r_mnt_idmap, &init_user_ns,
> +					  VFSUIDT_INIT(req->r_cred->fsuid));
> +		owner_fsgid = from_vfsgid(req->r_mnt_idmap, &init_user_ns,
> +					  VFSGIDT_INIT(req->r_cred->fsgid));
> +		nhead->owner_uid = cpu_to_le32(from_kuid(&init_user_ns, owner_fsuid));
> +		nhead->owner_gid = cpu_to_le32(from_kgid(&init_user_ns, owner_fsgid));
>   		p = msg->front.iov_base + sizeof(*nhead);
>   	}
>   
> diff --git a/fs/ceph/mds_client.h b/fs/ceph/mds_client.h
> index e3bbf3ba8ee8..8f683e8203bd 100644
> --- a/fs/ceph/mds_client.h
> +++ b/fs/ceph/mds_client.h
> @@ -33,8 +33,10 @@ enum ceph_feature_type {
>   	CEPHFS_FEATURE_NOTIFY_SESSION_STATE,
>   	CEPHFS_FEATURE_OP_GETVXATTR,
>   	CEPHFS_FEATURE_32BITS_RETRY_FWD,
> +	CEPHFS_FEATURE_NEW_SNAPREALM_INFO,
> +	CEPHFS_FEATURE_HAS_OWNER_UIDGID,
>   
> -	CEPHFS_FEATURE_MAX = CEPHFS_FEATURE_32BITS_RETRY_FWD,
> +	CEPHFS_FEATURE_MAX = CEPHFS_FEATURE_HAS_OWNER_UIDGID,
>   };
>   
>   #define CEPHFS_FEATURES_CLIENT_SUPPORTED {	\
> @@ -49,6 +51,7 @@ enum ceph_feature_type {
>   	CEPHFS_FEATURE_NOTIFY_SESSION_STATE,	\
>   	CEPHFS_FEATURE_OP_GETVXATTR,		\
>   	CEPHFS_FEATURE_32BITS_RETRY_FWD,	\
> +	CEPHFS_FEATURE_HAS_OWNER_UIDGID,	\
>   }
>   
>   /*
> diff --git a/include/linux/ceph/ceph_fs.h b/include/linux/ceph/ceph_fs.h
> index 5f2301ee88bc..b91699b08f26 100644
> --- a/include/linux/ceph/ceph_fs.h
> +++ b/include/linux/ceph/ceph_fs.h
> @@ -499,7 +499,7 @@ struct ceph_mds_request_head_legacy {
>   	union ceph_mds_request_args args;
>   } __attribute__ ((packed));
>   
> -#define CEPH_MDS_REQUEST_HEAD_VERSION  2
> +#define CEPH_MDS_REQUEST_HEAD_VERSION  3
>   
>   struct ceph_mds_request_head_old {
>   	__le16 version;                /* struct version */
> @@ -530,6 +530,9 @@ struct ceph_mds_request_head {
>   
>   	__le32 ext_num_retry;          /* new count retry attempts */
>   	__le32 ext_num_fwd;            /* new count fwd attempts */
> +
> +	__le32 struct_len;             /* to store size of struct ceph_mds_request_head */
> +	__le32 owner_uid, owner_gid;   /* used for OPs which create inodes */

Let's also initialize them to -1 for all the other requests as we do in 
your PR.

Thanks

- Xiubo



>   } __attribute__ ((packed));
>   
>   /* cap/lease release record */
  

On Mon, Aug 7, 2023 at 3:25 AM Xiubo Li <xiubli@redhat.com> wrote:
>
>
> On 8/4/23 16:48, Alexander Mikhalitsyn wrote:
> > From: Christian Brauner <brauner@kernel.org>
> >
> > Inode operations that create a new filesystem object such as ->mknod,
> > ->create, ->mkdir() and others don't take a {g,u}id argument explicitly.
> > Instead the caller's fs{g,u}id is used for the {g,u}id of the new
> > filesystem object.
> >
> > In order to ensure that the correct {g,u}id is used map the caller's
> > fs{g,u}id for creation requests. This doesn't require complex changes.
> > It suffices to pass in the relevant idmapping recorded in the request
> > message. If this request message was triggered from an inode operation
> > that creates filesystem objects it will have passed down the relevant
> > idmaping. If this is a request message that was triggered from an inode
> > operation that doens't need to take idmappings into account the initial
> > idmapping is passed down which is an identity mapping.
> >
> > This change uses a new cephfs protocol extension CEPHFS_FEATURE_HAS_OWNER_UIDGID
> > which adds two new fields (owner_{u,g}id) to the request head structure.
> > So, we need to ensure that MDS supports it otherwise we need to fail
> > any IO that comes through an idmapped mount because we can't process it
> > in a proper way. MDS server without such an extension will use caller_{u,g}id
> > fields to set a new inode owner UID/GID which is incorrect because caller_{u,g}id
> > values are unmapped. At the same time we can't map these fields with an
> > idmapping as it can break UID/GID-based permission checks logic on the
> > MDS side. This problem was described with a lot of details at [1], [2].
> >
> > [1] https://lore.kernel.org/lkml/CAEivzxfw1fHO2TFA4dx3u23ZKK6Q+EThfzuibrhA3RKM=ZOYLg@mail.gmail.com/
> > [2] https://lore.kernel.org/all/20220104140414.155198-3-brauner@kernel.org/
> >
> > Link: https://github.com/ceph/ceph/pull/52575
> > Link: https://tracker.ceph.com/issues/62217
> > Cc: Xiubo Li <xiubli@redhat.com>
> > Cc: Jeff Layton <jlayton@kernel.org>
> > Cc: Ilya Dryomov <idryomov@gmail.com>
> > Cc: ceph-devel@vger.kernel.org
> > Co-Developed-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>
> > Signed-off-by: Christian Brauner <brauner@kernel.org>
> > Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>
> > ---
> > v7:
> >       - reworked to use two new fields for owner UID/GID (https://github.com/ceph/ceph/pull/52575)
> > v8:
> >       - properly handled case when old MDS used with new kernel client
> > ---
> >   fs/ceph/mds_client.c         | 47 +++++++++++++++++++++++++++++++++---
> >   fs/ceph/mds_client.h         |  5 +++-
> >   include/linux/ceph/ceph_fs.h |  5 +++-
> >   3 files changed, 52 insertions(+), 5 deletions(-)
> >
> > diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
> > index 8829f55103da..41e4bf3811c4 100644
> > --- a/fs/ceph/mds_client.c
> > +++ b/fs/ceph/mds_client.c
> > @@ -2902,6 +2902,17 @@ static void encode_mclientrequest_tail(void **p, const struct ceph_mds_request *
> >       }
> >   }
> >
> > +static inline u16 mds_supported_head_version(struct ceph_mds_session *session)
> > +{
> > +     if (!test_bit(CEPHFS_FEATURE_32BITS_RETRY_FWD, &session->s_features))
> > +             return 1;
> > +
> > +     if (!test_bit(CEPHFS_FEATURE_HAS_OWNER_UIDGID, &session->s_features))
> > +             return 2;
> > +
> > +     return CEPH_MDS_REQUEST_HEAD_VERSION;
> > +}
> > +
> >   static struct ceph_mds_request_head_legacy *
> >   find_legacy_request_head(void *p, u64 features)
> >   {
> > @@ -2923,6 +2934,7 @@ static struct ceph_msg *create_request_message(struct ceph_mds_session *session,
> >   {
> >       int mds = session->s_mds;
> >       struct ceph_mds_client *mdsc = session->s_mdsc;
> > +     struct ceph_client *cl = mdsc->fsc->client;
> >       struct ceph_msg *msg;
> >       struct ceph_mds_request_head_legacy *lhead;
> >       const char *path1 = NULL;
> > @@ -2936,7 +2948,7 @@ static struct ceph_msg *create_request_message(struct ceph_mds_session *session,
> >       void *p, *end;
> >       int ret;
> >       bool legacy = !(session->s_con.peer_features & CEPH_FEATURE_FS_BTIME);
> > -     bool old_version = !test_bit(CEPHFS_FEATURE_32BITS_RETRY_FWD, &session->s_features);
> > +     u16 request_head_version = mds_supported_head_version(session);
> >
> >       ret = set_request_path_attr(mdsc, req->r_inode, req->r_dentry,
> >                             req->r_parent, req->r_path1, req->r_ino1.ino,
> > @@ -2977,8 +2989,10 @@ static struct ceph_msg *create_request_message(struct ceph_mds_session *session,
> >        */
> >       if (legacy)
> >               len = sizeof(struct ceph_mds_request_head_legacy);
> > -     else if (old_version)
> > +     else if (request_head_version == 1)
> >               len = sizeof(struct ceph_mds_request_head_old);
> > +     else if (request_head_version == 2)
> > +             len = offsetofend(struct ceph_mds_request_head, ext_num_fwd);
> >       else
> >               len = sizeof(struct ceph_mds_request_head);
> >
> > @@ -3028,6 +3042,16 @@ static struct ceph_msg *create_request_message(struct ceph_mds_session *session,
> >       lhead = find_legacy_request_head(msg->front.iov_base,
> >                                        session->s_con.peer_features);
> >
> > +     if ((req->r_mnt_idmap != &nop_mnt_idmap) &&
> > +         !test_bit(CEPHFS_FEATURE_HAS_OWNER_UIDGID, &session->s_features)) {
> > +             pr_err_ratelimited_client(cl,
> > +                     "idmapped mount is used and CEPHFS_FEATURE_HAS_OWNER_UIDGID"
> > +                     " is not supported by MDS. Fail request with -EIO.\n");
> > +
> > +             ret = -EIO;
> > +             goto out_err;
> > +     }
> > +
> >       /*
> >        * The ceph_mds_request_head_legacy didn't contain a version field, and
> >        * one was added when we moved the message version from 3->4.
> > @@ -3035,17 +3059,34 @@ static struct ceph_msg *create_request_message(struct ceph_mds_session *session,
> >       if (legacy) {
> >               msg->hdr.version = cpu_to_le16(3);
> >               p = msg->front.iov_base + sizeof(*lhead);
> > -     } else if (old_version) {
> > +     } else if (request_head_version == 1) {
> >               struct ceph_mds_request_head_old *ohead = msg->front.iov_base;
> >
> >               msg->hdr.version = cpu_to_le16(4);
> >               ohead->version = cpu_to_le16(1);
> >               p = msg->front.iov_base + sizeof(*ohead);
> > +     } else if (request_head_version == 2) {
> > +             struct ceph_mds_request_head *nhead = msg->front.iov_base;
> > +
> > +             msg->hdr.version = cpu_to_le16(6);
> > +             nhead->version = cpu_to_le16(2);
> > +
> > +             p = msg->front.iov_base + offsetofend(struct ceph_mds_request_head, ext_num_fwd);
> >       } else {
> >               struct ceph_mds_request_head *nhead = msg->front.iov_base;
> > +             kuid_t owner_fsuid;
> > +             kgid_t owner_fsgid;
> >
> >               msg->hdr.version = cpu_to_le16(6);
> >               nhead->version = cpu_to_le16(CEPH_MDS_REQUEST_HEAD_VERSION);
> > +             nhead->struct_len = sizeof(struct ceph_mds_request_head);
> > +
> > +             owner_fsuid = from_vfsuid(req->r_mnt_idmap, &init_user_ns,
> > +                                       VFSUIDT_INIT(req->r_cred->fsuid));
> > +             owner_fsgid = from_vfsgid(req->r_mnt_idmap, &init_user_ns,
> > +                                       VFSGIDT_INIT(req->r_cred->fsgid));
> > +             nhead->owner_uid = cpu_to_le32(from_kuid(&init_user_ns, owner_fsuid));
> > +             nhead->owner_gid = cpu_to_le32(from_kgid(&init_user_ns, owner_fsgid));
> >               p = msg->front.iov_base + sizeof(*nhead);
> >       }
> >
> > diff --git a/fs/ceph/mds_client.h b/fs/ceph/mds_client.h
> > index e3bbf3ba8ee8..8f683e8203bd 100644
> > --- a/fs/ceph/mds_client.h
> > +++ b/fs/ceph/mds_client.h
> > @@ -33,8 +33,10 @@ enum ceph_feature_type {
> >       CEPHFS_FEATURE_NOTIFY_SESSION_STATE,
> >       CEPHFS_FEATURE_OP_GETVXATTR,
> >       CEPHFS_FEATURE_32BITS_RETRY_FWD,
> > +     CEPHFS_FEATURE_NEW_SNAPREALM_INFO,
> > +     CEPHFS_FEATURE_HAS_OWNER_UIDGID,
> >
> > -     CEPHFS_FEATURE_MAX = CEPHFS_FEATURE_32BITS_RETRY_FWD,
> > +     CEPHFS_FEATURE_MAX = CEPHFS_FEATURE_HAS_OWNER_UIDGID,
> >   };
> >
> >   #define CEPHFS_FEATURES_CLIENT_SUPPORTED {  \
> > @@ -49,6 +51,7 @@ enum ceph_feature_type {
> >       CEPHFS_FEATURE_NOTIFY_SESSION_STATE,    \
> >       CEPHFS_FEATURE_OP_GETVXATTR,            \
> >       CEPHFS_FEATURE_32BITS_RETRY_FWD,        \
> > +     CEPHFS_FEATURE_HAS_OWNER_UIDGID,        \
> >   }
> >
> >   /*
> > diff --git a/include/linux/ceph/ceph_fs.h b/include/linux/ceph/ceph_fs.h
> > index 5f2301ee88bc..b91699b08f26 100644
> > --- a/include/linux/ceph/ceph_fs.h
> > +++ b/include/linux/ceph/ceph_fs.h
> > @@ -499,7 +499,7 @@ struct ceph_mds_request_head_legacy {
> >       union ceph_mds_request_args args;
> >   } __attribute__ ((packed));
> >
> > -#define CEPH_MDS_REQUEST_HEAD_VERSION  2
> > +#define CEPH_MDS_REQUEST_HEAD_VERSION  3
> >
> >   struct ceph_mds_request_head_old {
> >       __le16 version;                /* struct version */
> > @@ -530,6 +530,9 @@ struct ceph_mds_request_head {
> >
> >       __le32 ext_num_retry;          /* new count retry attempts */
> >       __le32 ext_num_fwd;            /* new count fwd attempts */
> > +
> > +     __le32 struct_len;             /* to store size of struct ceph_mds_request_head */
> > +     __le32 owner_uid, owner_gid;   /* used for OPs which create inodes */
>
> Let's also initialize them to -1 for all the other requests as we do in
> your PR.

They are always initialized already. As you can see from the code we
don't have any extra conditions
on filling these fields. We always fill them with an appropriate
UID/GID. If mount is not idmapped then it's just == caller_uid/gid,
if mount idmapped then it's idmapped caller_uid/gid.

Kind regards,
Alex

>
> Thanks
>
> - Xiubo
>
>
>
> >   } __attribute__ ((packed));
> >
> >   /* cap/lease release record */
>
  

On 8/7/23 14:51, Aleksandr Mikhalitsyn wrote:
> On Mon, Aug 7, 2023 at 3:25 AM Xiubo Li <xiubli@redhat.com> wrote:
>>
>> On 8/4/23 16:48, Alexander Mikhalitsyn wrote:
>>> From: Christian Brauner <brauner@kernel.org>
>>>
>>> Inode operations that create a new filesystem object such as ->mknod,
>>> ->create, ->mkdir() and others don't take a {g,u}id argument explicitly.
>>> Instead the caller's fs{g,u}id is used for the {g,u}id of the new
>>> filesystem object.
>>>
>>> In order to ensure that the correct {g,u}id is used map the caller's
>>> fs{g,u}id for creation requests. This doesn't require complex changes.
>>> It suffices to pass in the relevant idmapping recorded in the request
>>> message. If this request message was triggered from an inode operation
>>> that creates filesystem objects it will have passed down the relevant
>>> idmaping. If this is a request message that was triggered from an inode
>>> operation that doens't need to take idmappings into account the initial
>>> idmapping is passed down which is an identity mapping.
>>>
>>> This change uses a new cephfs protocol extension CEPHFS_FEATURE_HAS_OWNER_UIDGID
>>> which adds two new fields (owner_{u,g}id) to the request head structure.
>>> So, we need to ensure that MDS supports it otherwise we need to fail
>>> any IO that comes through an idmapped mount because we can't process it
>>> in a proper way. MDS server without such an extension will use caller_{u,g}id
>>> fields to set a new inode owner UID/GID which is incorrect because caller_{u,g}id
>>> values are unmapped. At the same time we can't map these fields with an
>>> idmapping as it can break UID/GID-based permission checks logic on the
>>> MDS side. This problem was described with a lot of details at [1], [2].
>>>
>>> [1] https://lore.kernel.org/lkml/CAEivzxfw1fHO2TFA4dx3u23ZKK6Q+EThfzuibrhA3RKM=ZOYLg@mail.gmail.com/
>>> [2] https://lore.kernel.org/all/20220104140414.155198-3-brauner@kernel.org/
>>>
>>> Link: https://github.com/ceph/ceph/pull/52575
>>> Link: https://tracker.ceph.com/issues/62217
>>> Cc: Xiubo Li <xiubli@redhat.com>
>>> Cc: Jeff Layton <jlayton@kernel.org>
>>> Cc: Ilya Dryomov <idryomov@gmail.com>
>>> Cc: ceph-devel@vger.kernel.org
>>> Co-Developed-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>
>>> Signed-off-by: Christian Brauner <brauner@kernel.org>
>>> Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>
>>> ---
>>> v7:
>>>        - reworked to use two new fields for owner UID/GID (https://github.com/ceph/ceph/pull/52575)
>>> v8:
>>>        - properly handled case when old MDS used with new kernel client
>>> ---
>>>    fs/ceph/mds_client.c         | 47 +++++++++++++++++++++++++++++++++---
>>>    fs/ceph/mds_client.h         |  5 +++-
>>>    include/linux/ceph/ceph_fs.h |  5 +++-
>>>    3 files changed, 52 insertions(+), 5 deletions(-)
>>>
>>> diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
>>> index 8829f55103da..41e4bf3811c4 100644
>>> --- a/fs/ceph/mds_client.c
>>> +++ b/fs/ceph/mds_client.c
>>> @@ -2902,6 +2902,17 @@ static void encode_mclientrequest_tail(void **p, const struct ceph_mds_request *
>>>        }
>>>    }
>>>
>>> +static inline u16 mds_supported_head_version(struct ceph_mds_session *session)
>>> +{
>>> +     if (!test_bit(CEPHFS_FEATURE_32BITS_RETRY_FWD, &session->s_features))
>>> +             return 1;
>>> +
>>> +     if (!test_bit(CEPHFS_FEATURE_HAS_OWNER_UIDGID, &session->s_features))
>>> +             return 2;
>>> +
>>> +     return CEPH_MDS_REQUEST_HEAD_VERSION;
>>> +}
>>> +
>>>    static struct ceph_mds_request_head_legacy *
>>>    find_legacy_request_head(void *p, u64 features)
>>>    {
>>> @@ -2923,6 +2934,7 @@ static struct ceph_msg *create_request_message(struct ceph_mds_session *session,
>>>    {
>>>        int mds = session->s_mds;
>>>        struct ceph_mds_client *mdsc = session->s_mdsc;
>>> +     struct ceph_client *cl = mdsc->fsc->client;
>>>        struct ceph_msg *msg;
>>>        struct ceph_mds_request_head_legacy *lhead;
>>>        const char *path1 = NULL;
>>> @@ -2936,7 +2948,7 @@ static struct ceph_msg *create_request_message(struct ceph_mds_session *session,
>>>        void *p, *end;
>>>        int ret;
>>>        bool legacy = !(session->s_con.peer_features & CEPH_FEATURE_FS_BTIME);
>>> -     bool old_version = !test_bit(CEPHFS_FEATURE_32BITS_RETRY_FWD, &session->s_features);
>>> +     u16 request_head_version = mds_supported_head_version(session);
>>>
>>>        ret = set_request_path_attr(mdsc, req->r_inode, req->r_dentry,
>>>                              req->r_parent, req->r_path1, req->r_ino1.ino,
>>> @@ -2977,8 +2989,10 @@ static struct ceph_msg *create_request_message(struct ceph_mds_session *session,
>>>         */
>>>        if (legacy)
>>>                len = sizeof(struct ceph_mds_request_head_legacy);
>>> -     else if (old_version)
>>> +     else if (request_head_version == 1)
>>>                len = sizeof(struct ceph_mds_request_head_old);
>>> +     else if (request_head_version == 2)
>>> +             len = offsetofend(struct ceph_mds_request_head, ext_num_fwd);
>>>        else
>>>                len = sizeof(struct ceph_mds_request_head);
>>>
>>> @@ -3028,6 +3042,16 @@ static struct ceph_msg *create_request_message(struct ceph_mds_session *session,
>>>        lhead = find_legacy_request_head(msg->front.iov_base,
>>>                                         session->s_con.peer_features);
>>>
>>> +     if ((req->r_mnt_idmap != &nop_mnt_idmap) &&
>>> +         !test_bit(CEPHFS_FEATURE_HAS_OWNER_UIDGID, &session->s_features)) {
>>> +             pr_err_ratelimited_client(cl,
>>> +                     "idmapped mount is used and CEPHFS_FEATURE_HAS_OWNER_UIDGID"
>>> +                     " is not supported by MDS. Fail request with -EIO.\n");
>>> +
>>> +             ret = -EIO;
>>> +             goto out_err;
>>> +     }
>>> +
>>>        /*
>>>         * The ceph_mds_request_head_legacy didn't contain a version field, and
>>>         * one was added when we moved the message version from 3->4.
>>> @@ -3035,17 +3059,34 @@ static struct ceph_msg *create_request_message(struct ceph_mds_session *session,
>>>        if (legacy) {
>>>                msg->hdr.version = cpu_to_le16(3);
>>>                p = msg->front.iov_base + sizeof(*lhead);
>>> -     } else if (old_version) {
>>> +     } else if (request_head_version == 1) {
>>>                struct ceph_mds_request_head_old *ohead = msg->front.iov_base;
>>>
>>>                msg->hdr.version = cpu_to_le16(4);
>>>                ohead->version = cpu_to_le16(1);
>>>                p = msg->front.iov_base + sizeof(*ohead);
>>> +     } else if (request_head_version == 2) {
>>> +             struct ceph_mds_request_head *nhead = msg->front.iov_base;
>>> +
>>> +             msg->hdr.version = cpu_to_le16(6);
>>> +             nhead->version = cpu_to_le16(2);
>>> +
>>> +             p = msg->front.iov_base + offsetofend(struct ceph_mds_request_head, ext_num_fwd);
>>>        } else {
>>>                struct ceph_mds_request_head *nhead = msg->front.iov_base;
>>> +             kuid_t owner_fsuid;
>>> +             kgid_t owner_fsgid;
>>>
>>>                msg->hdr.version = cpu_to_le16(6);
>>>                nhead->version = cpu_to_le16(CEPH_MDS_REQUEST_HEAD_VERSION);
>>> +             nhead->struct_len = sizeof(struct ceph_mds_request_head);
>>> +
>>> +             owner_fsuid = from_vfsuid(req->r_mnt_idmap, &init_user_ns,
>>> +                                       VFSUIDT_INIT(req->r_cred->fsuid));
>>> +             owner_fsgid = from_vfsgid(req->r_mnt_idmap, &init_user_ns,
>>> +                                       VFSGIDT_INIT(req->r_cred->fsgid));
>>> +             nhead->owner_uid = cpu_to_le32(from_kuid(&init_user_ns, owner_fsuid));
>>> +             nhead->owner_gid = cpu_to_le32(from_kgid(&init_user_ns, owner_fsgid));
>>>                p = msg->front.iov_base + sizeof(*nhead);
>>>        }
>>>
>>> diff --git a/fs/ceph/mds_client.h b/fs/ceph/mds_client.h
>>> index e3bbf3ba8ee8..8f683e8203bd 100644
>>> --- a/fs/ceph/mds_client.h
>>> +++ b/fs/ceph/mds_client.h
>>> @@ -33,8 +33,10 @@ enum ceph_feature_type {
>>>        CEPHFS_FEATURE_NOTIFY_SESSION_STATE,
>>>        CEPHFS_FEATURE_OP_GETVXATTR,
>>>        CEPHFS_FEATURE_32BITS_RETRY_FWD,
>>> +     CEPHFS_FEATURE_NEW_SNAPREALM_INFO,
>>> +     CEPHFS_FEATURE_HAS_OWNER_UIDGID,
>>>
>>> -     CEPHFS_FEATURE_MAX = CEPHFS_FEATURE_32BITS_RETRY_FWD,
>>> +     CEPHFS_FEATURE_MAX = CEPHFS_FEATURE_HAS_OWNER_UIDGID,
>>>    };
>>>
>>>    #define CEPHFS_FEATURES_CLIENT_SUPPORTED {  \
>>> @@ -49,6 +51,7 @@ enum ceph_feature_type {
>>>        CEPHFS_FEATURE_NOTIFY_SESSION_STATE,    \
>>>        CEPHFS_FEATURE_OP_GETVXATTR,            \
>>>        CEPHFS_FEATURE_32BITS_RETRY_FWD,        \
>>> +     CEPHFS_FEATURE_HAS_OWNER_UIDGID,        \
>>>    }
>>>
>>>    /*
>>> diff --git a/include/linux/ceph/ceph_fs.h b/include/linux/ceph/ceph_fs.h
>>> index 5f2301ee88bc..b91699b08f26 100644
>>> --- a/include/linux/ceph/ceph_fs.h
>>> +++ b/include/linux/ceph/ceph_fs.h
>>> @@ -499,7 +499,7 @@ struct ceph_mds_request_head_legacy {
>>>        union ceph_mds_request_args args;
>>>    } __attribute__ ((packed));
>>>
>>> -#define CEPH_MDS_REQUEST_HEAD_VERSION  2
>>> +#define CEPH_MDS_REQUEST_HEAD_VERSION  3
>>>
>>>    struct ceph_mds_request_head_old {
>>>        __le16 version;                /* struct version */
>>> @@ -530,6 +530,9 @@ struct ceph_mds_request_head {
>>>
>>>        __le32 ext_num_retry;          /* new count retry attempts */
>>>        __le32 ext_num_fwd;            /* new count fwd attempts */
>>> +
>>> +     __le32 struct_len;             /* to store size of struct ceph_mds_request_head */
>>> +     __le32 owner_uid, owner_gid;   /* used for OPs which create inodes */
>> Let's also initialize them to -1 for all the other requests as we do in
>> your PR.
> They are always initialized already. As you can see from the code we
> don't have any extra conditions
> on filling these fields. We always fill them with an appropriate
> UID/GID. If mount is not idmapped then it's just == caller_uid/gid,
> if mount idmapped then it's idmapped caller_uid/gid.

Then in kclient all the request will always initialized the 
'owner_{uid/gid}' with 'caller_{uid/gid}'. While in userspace libcephfs 
it will only set them for 'create/mknod/mkdir/symlink` instead.

I'd prefer to make them consistent, which is what I am still focusing 
on, to make them easier to read and comparing when troubles hooting.

Thanks

- Xiubo

> Kind regards,
> Alex
>
>> Thanks
>>
>> - Xiubo
>>
>>
>>
>>>    } __attribute__ ((packed));
>>>
>>>    /* cap/lease release record */
  

On Mon, Aug 7, 2023 at 12:28 PM Xiubo Li <xiubli@redhat.com> wrote:
>
>
> On 8/7/23 14:51, Aleksandr Mikhalitsyn wrote:
> > On Mon, Aug 7, 2023 at 3:25 AM Xiubo Li <xiubli@redhat.com> wrote:
> >>
> >> On 8/4/23 16:48, Alexander Mikhalitsyn wrote:
> >>> From: Christian Brauner <brauner@kernel.org>
> >>>
> >>> Inode operations that create a new filesystem object such as ->mknod,
> >>> ->create, ->mkdir() and others don't take a {g,u}id argument explicitly.
> >>> Instead the caller's fs{g,u}id is used for the {g,u}id of the new
> >>> filesystem object.
> >>>
> >>> In order to ensure that the correct {g,u}id is used map the caller's
> >>> fs{g,u}id for creation requests. This doesn't require complex changes.
> >>> It suffices to pass in the relevant idmapping recorded in the request
> >>> message. If this request message was triggered from an inode operation
> >>> that creates filesystem objects it will have passed down the relevant
> >>> idmaping. If this is a request message that was triggered from an inode
> >>> operation that doens't need to take idmappings into account the initial
> >>> idmapping is passed down which is an identity mapping.
> >>>
> >>> This change uses a new cephfs protocol extension CEPHFS_FEATURE_HAS_OWNER_UIDGID
> >>> which adds two new fields (owner_{u,g}id) to the request head structure.
> >>> So, we need to ensure that MDS supports it otherwise we need to fail
> >>> any IO that comes through an idmapped mount because we can't process it
> >>> in a proper way. MDS server without such an extension will use caller_{u,g}id
> >>> fields to set a new inode owner UID/GID which is incorrect because caller_{u,g}id
> >>> values are unmapped. At the same time we can't map these fields with an
> >>> idmapping as it can break UID/GID-based permission checks logic on the
> >>> MDS side. This problem was described with a lot of details at [1], [2].
> >>>
> >>> [1] https://lore.kernel.org/lkml/CAEivzxfw1fHO2TFA4dx3u23ZKK6Q+EThfzuibrhA3RKM=ZOYLg@mail.gmail.com/
> >>> [2] https://lore.kernel.org/all/20220104140414.155198-3-brauner@kernel.org/
> >>>
> >>> Link: https://github.com/ceph/ceph/pull/52575
> >>> Link: https://tracker.ceph.com/issues/62217
> >>> Cc: Xiubo Li <xiubli@redhat.com>
> >>> Cc: Jeff Layton <jlayton@kernel.org>
> >>> Cc: Ilya Dryomov <idryomov@gmail.com>
> >>> Cc: ceph-devel@vger.kernel.org
> >>> Co-Developed-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>
> >>> Signed-off-by: Christian Brauner <brauner@kernel.org>
> >>> Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>
> >>> ---
> >>> v7:
> >>>        - reworked to use two new fields for owner UID/GID (https://github.com/ceph/ceph/pull/52575)
> >>> v8:
> >>>        - properly handled case when old MDS used with new kernel client
> >>> ---
> >>>    fs/ceph/mds_client.c         | 47 +++++++++++++++++++++++++++++++++---
> >>>    fs/ceph/mds_client.h         |  5 +++-
> >>>    include/linux/ceph/ceph_fs.h |  5 +++-
> >>>    3 files changed, 52 insertions(+), 5 deletions(-)
> >>>
> >>> diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
> >>> index 8829f55103da..41e4bf3811c4 100644
> >>> --- a/fs/ceph/mds_client.c
> >>> +++ b/fs/ceph/mds_client.c
> >>> @@ -2902,6 +2902,17 @@ static void encode_mclientrequest_tail(void **p, const struct ceph_mds_request *
> >>>        }
> >>>    }
> >>>
> >>> +static inline u16 mds_supported_head_version(struct ceph_mds_session *session)
> >>> +{
> >>> +     if (!test_bit(CEPHFS_FEATURE_32BITS_RETRY_FWD, &session->s_features))
> >>> +             return 1;
> >>> +
> >>> +     if (!test_bit(CEPHFS_FEATURE_HAS_OWNER_UIDGID, &session->s_features))
> >>> +             return 2;
> >>> +
> >>> +     return CEPH_MDS_REQUEST_HEAD_VERSION;
> >>> +}
> >>> +
> >>>    static struct ceph_mds_request_head_legacy *
> >>>    find_legacy_request_head(void *p, u64 features)
> >>>    {
> >>> @@ -2923,6 +2934,7 @@ static struct ceph_msg *create_request_message(struct ceph_mds_session *session,
> >>>    {
> >>>        int mds = session->s_mds;
> >>>        struct ceph_mds_client *mdsc = session->s_mdsc;
> >>> +     struct ceph_client *cl = mdsc->fsc->client;
> >>>        struct ceph_msg *msg;
> >>>        struct ceph_mds_request_head_legacy *lhead;
> >>>        const char *path1 = NULL;
> >>> @@ -2936,7 +2948,7 @@ static struct ceph_msg *create_request_message(struct ceph_mds_session *session,
> >>>        void *p, *end;
> >>>        int ret;
> >>>        bool legacy = !(session->s_con.peer_features & CEPH_FEATURE_FS_BTIME);
> >>> -     bool old_version = !test_bit(CEPHFS_FEATURE_32BITS_RETRY_FWD, &session->s_features);
> >>> +     u16 request_head_version = mds_supported_head_version(session);
> >>>
> >>>        ret = set_request_path_attr(mdsc, req->r_inode, req->r_dentry,
> >>>                              req->r_parent, req->r_path1, req->r_ino1.ino,
> >>> @@ -2977,8 +2989,10 @@ static struct ceph_msg *create_request_message(struct ceph_mds_session *session,
> >>>         */
> >>>        if (legacy)
> >>>                len = sizeof(struct ceph_mds_request_head_legacy);
> >>> -     else if (old_version)
> >>> +     else if (request_head_version == 1)
> >>>                len = sizeof(struct ceph_mds_request_head_old);
> >>> +     else if (request_head_version == 2)
> >>> +             len = offsetofend(struct ceph_mds_request_head, ext_num_fwd);
> >>>        else
> >>>                len = sizeof(struct ceph_mds_request_head);
> >>>
> >>> @@ -3028,6 +3042,16 @@ static struct ceph_msg *create_request_message(struct ceph_mds_session *session,
> >>>        lhead = find_legacy_request_head(msg->front.iov_base,
> >>>                                         session->s_con.peer_features);
> >>>
> >>> +     if ((req->r_mnt_idmap != &nop_mnt_idmap) &&
> >>> +         !test_bit(CEPHFS_FEATURE_HAS_OWNER_UIDGID, &session->s_features)) {
> >>> +             pr_err_ratelimited_client(cl,
> >>> +                     "idmapped mount is used and CEPHFS_FEATURE_HAS_OWNER_UIDGID"
> >>> +                     " is not supported by MDS. Fail request with -EIO.\n");
> >>> +
> >>> +             ret = -EIO;
> >>> +             goto out_err;
> >>> +     }
> >>> +
> >>>        /*
> >>>         * The ceph_mds_request_head_legacy didn't contain a version field, and
> >>>         * one was added when we moved the message version from 3->4.
> >>> @@ -3035,17 +3059,34 @@ static struct ceph_msg *create_request_message(struct ceph_mds_session *session,
> >>>        if (legacy) {
> >>>                msg->hdr.version = cpu_to_le16(3);
> >>>                p = msg->front.iov_base + sizeof(*lhead);
> >>> -     } else if (old_version) {
> >>> +     } else if (request_head_version == 1) {
> >>>                struct ceph_mds_request_head_old *ohead = msg->front.iov_base;
> >>>
> >>>                msg->hdr.version = cpu_to_le16(4);
> >>>                ohead->version = cpu_to_le16(1);
> >>>                p = msg->front.iov_base + sizeof(*ohead);
> >>> +     } else if (request_head_version == 2) {
> >>> +             struct ceph_mds_request_head *nhead = msg->front.iov_base;
> >>> +
> >>> +             msg->hdr.version = cpu_to_le16(6);
> >>> +             nhead->version = cpu_to_le16(2);
> >>> +
> >>> +             p = msg->front.iov_base + offsetofend(struct ceph_mds_request_head, ext_num_fwd);
> >>>        } else {
> >>>                struct ceph_mds_request_head *nhead = msg->front.iov_base;
> >>> +             kuid_t owner_fsuid;
> >>> +             kgid_t owner_fsgid;
> >>>
> >>>                msg->hdr.version = cpu_to_le16(6);
> >>>                nhead->version = cpu_to_le16(CEPH_MDS_REQUEST_HEAD_VERSION);
> >>> +             nhead->struct_len = sizeof(struct ceph_mds_request_head);
> >>> +
> >>> +             owner_fsuid = from_vfsuid(req->r_mnt_idmap, &init_user_ns,
> >>> +                                       VFSUIDT_INIT(req->r_cred->fsuid));
> >>> +             owner_fsgid = from_vfsgid(req->r_mnt_idmap, &init_user_ns,
> >>> +                                       VFSGIDT_INIT(req->r_cred->fsgid));
> >>> +             nhead->owner_uid = cpu_to_le32(from_kuid(&init_user_ns, owner_fsuid));
> >>> +             nhead->owner_gid = cpu_to_le32(from_kgid(&init_user_ns, owner_fsgid));
> >>>                p = msg->front.iov_base + sizeof(*nhead);
> >>>        }
> >>>
> >>> diff --git a/fs/ceph/mds_client.h b/fs/ceph/mds_client.h
> >>> index e3bbf3ba8ee8..8f683e8203bd 100644
> >>> --- a/fs/ceph/mds_client.h
> >>> +++ b/fs/ceph/mds_client.h
> >>> @@ -33,8 +33,10 @@ enum ceph_feature_type {
> >>>        CEPHFS_FEATURE_NOTIFY_SESSION_STATE,
> >>>        CEPHFS_FEATURE_OP_GETVXATTR,
> >>>        CEPHFS_FEATURE_32BITS_RETRY_FWD,
> >>> +     CEPHFS_FEATURE_NEW_SNAPREALM_INFO,
> >>> +     CEPHFS_FEATURE_HAS_OWNER_UIDGID,
> >>>
> >>> -     CEPHFS_FEATURE_MAX = CEPHFS_FEATURE_32BITS_RETRY_FWD,
> >>> +     CEPHFS_FEATURE_MAX = CEPHFS_FEATURE_HAS_OWNER_UIDGID,
> >>>    };
> >>>
> >>>    #define CEPHFS_FEATURES_CLIENT_SUPPORTED {  \
> >>> @@ -49,6 +51,7 @@ enum ceph_feature_type {
> >>>        CEPHFS_FEATURE_NOTIFY_SESSION_STATE,    \
> >>>        CEPHFS_FEATURE_OP_GETVXATTR,            \
> >>>        CEPHFS_FEATURE_32BITS_RETRY_FWD,        \
> >>> +     CEPHFS_FEATURE_HAS_OWNER_UIDGID,        \
> >>>    }
> >>>
> >>>    /*
> >>> diff --git a/include/linux/ceph/ceph_fs.h b/include/linux/ceph/ceph_fs.h
> >>> index 5f2301ee88bc..b91699b08f26 100644
> >>> --- a/include/linux/ceph/ceph_fs.h
> >>> +++ b/include/linux/ceph/ceph_fs.h
> >>> @@ -499,7 +499,7 @@ struct ceph_mds_request_head_legacy {
> >>>        union ceph_mds_request_args args;
> >>>    } __attribute__ ((packed));
> >>>
> >>> -#define CEPH_MDS_REQUEST_HEAD_VERSION  2
> >>> +#define CEPH_MDS_REQUEST_HEAD_VERSION  3
> >>>
> >>>    struct ceph_mds_request_head_old {
> >>>        __le16 version;                /* struct version */
> >>> @@ -530,6 +530,9 @@ struct ceph_mds_request_head {
> >>>
> >>>        __le32 ext_num_retry;          /* new count retry attempts */
> >>>        __le32 ext_num_fwd;            /* new count fwd attempts */
> >>> +
> >>> +     __le32 struct_len;             /* to store size of struct ceph_mds_request_head */
> >>> +     __le32 owner_uid, owner_gid;   /* used for OPs which create inodes */
> >> Let's also initialize them to -1 for all the other requests as we do in
> >> your PR.
> > They are always initialized already. As you can see from the code we
> > don't have any extra conditions
> > on filling these fields. We always fill them with an appropriate
> > UID/GID. If mount is not idmapped then it's just == caller_uid/gid,
> > if mount idmapped then it's idmapped caller_uid/gid.
>
> Then in kclient all the request will always initialized the
> 'owner_{uid/gid}' with 'caller_{uid/gid}'. While in userspace libcephfs
> it will only set them for 'create/mknod/mkdir/symlink` instead.
>
> I'd prefer to make them consistent, which is what I am still focusing
> on, to make them easier to read and comparing when troubles hooting.

Dear Xiubo,

Sure, I will do it.

Couldn't you please review all the rest of the patches before I fix
this particular thing?
It will allow me to fix and send -v10 with all required fixes
incorporated in it.

Kind regards,
Alex

>
> Thanks
>
> - Xiubo
>
> > Kind regards,
> > Alex
> >
> >> Thanks
> >>
> >> - Xiubo
> >>
> >>
> >>
> >>>    } __attribute__ ((packed));
> >>>
> >>>    /* cap/lease release record */
>
  

On 8/7/23 18:34, Aleksandr Mikhalitsyn wrote:
> On Mon, Aug 7, 2023 at 12:28 PM Xiubo Li <xiubli@redhat.com> wrote:
>>
>> On 8/7/23 14:51, Aleksandr Mikhalitsyn wrote:
>>> On Mon, Aug 7, 2023 at 3:25 AM Xiubo Li <xiubli@redhat.com> wrote:
>>>> On 8/4/23 16:48, Alexander Mikhalitsyn wrote:
>>>>> From: Christian Brauner <brauner@kernel.org>
>>>>>
>>>>> Inode operations that create a new filesystem object such as ->mknod,
>>>>> ->create, ->mkdir() and others don't take a {g,u}id argument explicitly.
>>>>> Instead the caller's fs{g,u}id is used for the {g,u}id of the new
>>>>> filesystem object.
>>>>>
>>>>> In order to ensure that the correct {g,u}id is used map the caller's
>>>>> fs{g,u}id for creation requests. This doesn't require complex changes.
>>>>> It suffices to pass in the relevant idmapping recorded in the request
>>>>> message. If this request message was triggered from an inode operation
>>>>> that creates filesystem objects it will have passed down the relevant
>>>>> idmaping. If this is a request message that was triggered from an inode
>>>>> operation that doens't need to take idmappings into account the initial
>>>>> idmapping is passed down which is an identity mapping.
>>>>>
>>>>> This change uses a new cephfs protocol extension CEPHFS_FEATURE_HAS_OWNER_UIDGID
>>>>> which adds two new fields (owner_{u,g}id) to the request head structure.
>>>>> So, we need to ensure that MDS supports it otherwise we need to fail
>>>>> any IO that comes through an idmapped mount because we can't process it
>>>>> in a proper way. MDS server without such an extension will use caller_{u,g}id
>>>>> fields to set a new inode owner UID/GID which is incorrect because caller_{u,g}id
>>>>> values are unmapped. At the same time we can't map these fields with an
>>>>> idmapping as it can break UID/GID-based permission checks logic on the
>>>>> MDS side. This problem was described with a lot of details at [1], [2].
>>>>>
>>>>> [1] https://lore.kernel.org/lkml/CAEivzxfw1fHO2TFA4dx3u23ZKK6Q+EThfzuibrhA3RKM=ZOYLg@mail.gmail.com/
>>>>> [2] https://lore.kernel.org/all/20220104140414.155198-3-brauner@kernel.org/
>>>>>
>>>>> Link: https://github.com/ceph/ceph/pull/52575
>>>>> Link: https://tracker.ceph.com/issues/62217
>>>>> Cc: Xiubo Li <xiubli@redhat.com>
>>>>> Cc: Jeff Layton <jlayton@kernel.org>
>>>>> Cc: Ilya Dryomov <idryomov@gmail.com>
>>>>> Cc: ceph-devel@vger.kernel.org
>>>>> Co-Developed-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>
>>>>> Signed-off-by: Christian Brauner <brauner@kernel.org>
>>>>> Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>
>>>>> ---
>>>>> v7:
>>>>>         - reworked to use two new fields for owner UID/GID (https://github.com/ceph/ceph/pull/52575)
>>>>> v8:
>>>>>         - properly handled case when old MDS used with new kernel client
>>>>> ---
>>>>>     fs/ceph/mds_client.c         | 47 +++++++++++++++++++++++++++++++++---
>>>>>     fs/ceph/mds_client.h         |  5 +++-
>>>>>     include/linux/ceph/ceph_fs.h |  5 +++-
>>>>>     3 files changed, 52 insertions(+), 5 deletions(-)
>>>>>
>>>>> diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
>>>>> index 8829f55103da..41e4bf3811c4 100644
>>>>> --- a/fs/ceph/mds_client.c
>>>>> +++ b/fs/ceph/mds_client.c
>>>>> @@ -2902,6 +2902,17 @@ static void encode_mclientrequest_tail(void **p, const struct ceph_mds_request *
>>>>>         }
>>>>>     }
>>>>>
>>>>> +static inline u16 mds_supported_head_version(struct ceph_mds_session *session)
>>>>> +{
>>>>> +     if (!test_bit(CEPHFS_FEATURE_32BITS_RETRY_FWD, &session->s_features))
>>>>> +             return 1;
>>>>> +
>>>>> +     if (!test_bit(CEPHFS_FEATURE_HAS_OWNER_UIDGID, &session->s_features))
>>>>> +             return 2;
>>>>> +
>>>>> +     return CEPH_MDS_REQUEST_HEAD_VERSION;
>>>>> +}
>>>>> +
>>>>>     static struct ceph_mds_request_head_legacy *
>>>>>     find_legacy_request_head(void *p, u64 features)
>>>>>     {
>>>>> @@ -2923,6 +2934,7 @@ static struct ceph_msg *create_request_message(struct ceph_mds_session *session,
>>>>>     {
>>>>>         int mds = session->s_mds;
>>>>>         struct ceph_mds_client *mdsc = session->s_mdsc;
>>>>> +     struct ceph_client *cl = mdsc->fsc->client;
>>>>>         struct ceph_msg *msg;
>>>>>         struct ceph_mds_request_head_legacy *lhead;
>>>>>         const char *path1 = NULL;
>>>>> @@ -2936,7 +2948,7 @@ static struct ceph_msg *create_request_message(struct ceph_mds_session *session,
>>>>>         void *p, *end;
>>>>>         int ret;
>>>>>         bool legacy = !(session->s_con.peer_features & CEPH_FEATURE_FS_BTIME);
>>>>> -     bool old_version = !test_bit(CEPHFS_FEATURE_32BITS_RETRY_FWD, &session->s_features);
>>>>> +     u16 request_head_version = mds_supported_head_version(session);
>>>>>
>>>>>         ret = set_request_path_attr(mdsc, req->r_inode, req->r_dentry,
>>>>>                               req->r_parent, req->r_path1, req->r_ino1.ino,
>>>>> @@ -2977,8 +2989,10 @@ static struct ceph_msg *create_request_message(struct ceph_mds_session *session,
>>>>>          */
>>>>>         if (legacy)
>>>>>                 len = sizeof(struct ceph_mds_request_head_legacy);
>>>>> -     else if (old_version)
>>>>> +     else if (request_head_version == 1)
>>>>>                 len = sizeof(struct ceph_mds_request_head_old);
>>>>> +     else if (request_head_version == 2)
>>>>> +             len = offsetofend(struct ceph_mds_request_head, ext_num_fwd);
>>>>>         else
>>>>>                 len = sizeof(struct ceph_mds_request_head);
>>>>>
>>>>> @@ -3028,6 +3042,16 @@ static struct ceph_msg *create_request_message(struct ceph_mds_session *session,
>>>>>         lhead = find_legacy_request_head(msg->front.iov_base,
>>>>>                                          session->s_con.peer_features);
>>>>>
>>>>> +     if ((req->r_mnt_idmap != &nop_mnt_idmap) &&
>>>>> +         !test_bit(CEPHFS_FEATURE_HAS_OWNER_UIDGID, &session->s_features)) {
>>>>> +             pr_err_ratelimited_client(cl,
>>>>> +                     "idmapped mount is used and CEPHFS_FEATURE_HAS_OWNER_UIDGID"
>>>>> +                     " is not supported by MDS. Fail request with -EIO.\n");
>>>>> +
>>>>> +             ret = -EIO;
>>>>> +             goto out_err;
>>>>> +     }
>>>>> +
>>>>>         /*
>>>>>          * The ceph_mds_request_head_legacy didn't contain a version field, and
>>>>>          * one was added when we moved the message version from 3->4.
>>>>> @@ -3035,17 +3059,34 @@ static struct ceph_msg *create_request_message(struct ceph_mds_session *session,
>>>>>         if (legacy) {
>>>>>                 msg->hdr.version = cpu_to_le16(3);
>>>>>                 p = msg->front.iov_base + sizeof(*lhead);
>>>>> -     } else if (old_version) {
>>>>> +     } else if (request_head_version == 1) {
>>>>>                 struct ceph_mds_request_head_old *ohead = msg->front.iov_base;
>>>>>
>>>>>                 msg->hdr.version = cpu_to_le16(4);
>>>>>                 ohead->version = cpu_to_le16(1);
>>>>>                 p = msg->front.iov_base + sizeof(*ohead);
>>>>> +     } else if (request_head_version == 2) {
>>>>> +             struct ceph_mds_request_head *nhead = msg->front.iov_base;
>>>>> +
>>>>> +             msg->hdr.version = cpu_to_le16(6);
>>>>> +             nhead->version = cpu_to_le16(2);
>>>>> +
>>>>> +             p = msg->front.iov_base + offsetofend(struct ceph_mds_request_head, ext_num_fwd);
>>>>>         } else {
>>>>>                 struct ceph_mds_request_head *nhead = msg->front.iov_base;
>>>>> +             kuid_t owner_fsuid;
>>>>> +             kgid_t owner_fsgid;
>>>>>
>>>>>                 msg->hdr.version = cpu_to_le16(6);
>>>>>                 nhead->version = cpu_to_le16(CEPH_MDS_REQUEST_HEAD_VERSION);
>>>>> +             nhead->struct_len = sizeof(struct ceph_mds_request_head);
>>>>> +
>>>>> +             owner_fsuid = from_vfsuid(req->r_mnt_idmap, &init_user_ns,
>>>>> +                                       VFSUIDT_INIT(req->r_cred->fsuid));
>>>>> +             owner_fsgid = from_vfsgid(req->r_mnt_idmap, &init_user_ns,
>>>>> +                                       VFSGIDT_INIT(req->r_cred->fsgid));
>>>>> +             nhead->owner_uid = cpu_to_le32(from_kuid(&init_user_ns, owner_fsuid));
>>>>> +             nhead->owner_gid = cpu_to_le32(from_kgid(&init_user_ns, owner_fsgid));
>>>>>                 p = msg->front.iov_base + sizeof(*nhead);
>>>>>         }
>>>>>
>>>>> diff --git a/fs/ceph/mds_client.h b/fs/ceph/mds_client.h
>>>>> index e3bbf3ba8ee8..8f683e8203bd 100644
>>>>> --- a/fs/ceph/mds_client.h
>>>>> +++ b/fs/ceph/mds_client.h
>>>>> @@ -33,8 +33,10 @@ enum ceph_feature_type {
>>>>>         CEPHFS_FEATURE_NOTIFY_SESSION_STATE,
>>>>>         CEPHFS_FEATURE_OP_GETVXATTR,
>>>>>         CEPHFS_FEATURE_32BITS_RETRY_FWD,
>>>>> +     CEPHFS_FEATURE_NEW_SNAPREALM_INFO,
>>>>> +     CEPHFS_FEATURE_HAS_OWNER_UIDGID,
>>>>>
>>>>> -     CEPHFS_FEATURE_MAX = CEPHFS_FEATURE_32BITS_RETRY_FWD,
>>>>> +     CEPHFS_FEATURE_MAX = CEPHFS_FEATURE_HAS_OWNER_UIDGID,
>>>>>     };
>>>>>
>>>>>     #define CEPHFS_FEATURES_CLIENT_SUPPORTED {  \
>>>>> @@ -49,6 +51,7 @@ enum ceph_feature_type {
>>>>>         CEPHFS_FEATURE_NOTIFY_SESSION_STATE,    \
>>>>>         CEPHFS_FEATURE_OP_GETVXATTR,            \
>>>>>         CEPHFS_FEATURE_32BITS_RETRY_FWD,        \
>>>>> +     CEPHFS_FEATURE_HAS_OWNER_UIDGID,        \
>>>>>     }
>>>>>
>>>>>     /*
>>>>> diff --git a/include/linux/ceph/ceph_fs.h b/include/linux/ceph/ceph_fs.h
>>>>> index 5f2301ee88bc..b91699b08f26 100644
>>>>> --- a/include/linux/ceph/ceph_fs.h
>>>>> +++ b/include/linux/ceph/ceph_fs.h
>>>>> @@ -499,7 +499,7 @@ struct ceph_mds_request_head_legacy {
>>>>>         union ceph_mds_request_args args;
>>>>>     } __attribute__ ((packed));
>>>>>
>>>>> -#define CEPH_MDS_REQUEST_HEAD_VERSION  2
>>>>> +#define CEPH_MDS_REQUEST_HEAD_VERSION  3
>>>>>
>>>>>     struct ceph_mds_request_head_old {
>>>>>         __le16 version;                /* struct version */
>>>>> @@ -530,6 +530,9 @@ struct ceph_mds_request_head {
>>>>>
>>>>>         __le32 ext_num_retry;          /* new count retry attempts */
>>>>>         __le32 ext_num_fwd;            /* new count fwd attempts */
>>>>> +
>>>>> +     __le32 struct_len;             /* to store size of struct ceph_mds_request_head */
>>>>> +     __le32 owner_uid, owner_gid;   /* used for OPs which create inodes */
>>>> Let's also initialize them to -1 for all the other requests as we do in
>>>> your PR.
>>> They are always initialized already. As you can see from the code we
>>> don't have any extra conditions
>>> on filling these fields. We always fill them with an appropriate
>>> UID/GID. If mount is not idmapped then it's just == caller_uid/gid,
>>> if mount idmapped then it's idmapped caller_uid/gid.
>> Then in kclient all the request will always initialized the
>> 'owner_{uid/gid}' with 'caller_{uid/gid}'. While in userspace libcephfs
>> it will only set them for 'create/mknod/mkdir/symlink` instead.
>>
>> I'd prefer to make them consistent, which is what I am still focusing
>> on, to make them easier to read and comparing when troubles hooting.
> Dear Xiubo,
>
> Sure, I will do it.
>
> Couldn't you please review all the rest of the patches before I fix
> this particular thing?
> It will allow me to fix and send -v10 with all required fixes
> incorporated in it.

I have gone through them all and they LGTM.

Thanks

- Xiubo


> Kind regards,
> Alex
>
>> Thanks
>>
>> - Xiubo
>>
>>> Kind regards,
>>> Alex
>>>
>>>> Thanks
>>>>
>>>> - Xiubo
>>>>
>>>>
>>>>
>>>>>     } __attribute__ ((packed));
>>>>>
>>>>>     /* cap/lease release record */
  

On Mon, Aug 7, 2023 at 1:21 PM Xiubo Li <xiubli@redhat.com> wrote:
>
>
> On 8/7/23 18:34, Aleksandr Mikhalitsyn wrote:
> > On Mon, Aug 7, 2023 at 12:28 PM Xiubo Li <xiubli@redhat.com> wrote:
> >>
> >> On 8/7/23 14:51, Aleksandr Mikhalitsyn wrote:
> >>> On Mon, Aug 7, 2023 at 3:25 AM Xiubo Li <xiubli@redhat.com> wrote:
> >>>> On 8/4/23 16:48, Alexander Mikhalitsyn wrote:
> >>>>> From: Christian Brauner <brauner@kernel.org>
> >>>>>
> >>>>> Inode operations that create a new filesystem object such as ->mknod,
> >>>>> ->create, ->mkdir() and others don't take a {g,u}id argument explicitly.
> >>>>> Instead the caller's fs{g,u}id is used for the {g,u}id of the new
> >>>>> filesystem object.
> >>>>>
> >>>>> In order to ensure that the correct {g,u}id is used map the caller's
> >>>>> fs{g,u}id for creation requests. This doesn't require complex changes.
> >>>>> It suffices to pass in the relevant idmapping recorded in the request
> >>>>> message. If this request message was triggered from an inode operation
> >>>>> that creates filesystem objects it will have passed down the relevant
> >>>>> idmaping. If this is a request message that was triggered from an inode
> >>>>> operation that doens't need to take idmappings into account the initial
> >>>>> idmapping is passed down which is an identity mapping.
> >>>>>
> >>>>> This change uses a new cephfs protocol extension CEPHFS_FEATURE_HAS_OWNER_UIDGID
> >>>>> which adds two new fields (owner_{u,g}id) to the request head structure.
> >>>>> So, we need to ensure that MDS supports it otherwise we need to fail
> >>>>> any IO that comes through an idmapped mount because we can't process it
> >>>>> in a proper way. MDS server without such an extension will use caller_{u,g}id
> >>>>> fields to set a new inode owner UID/GID which is incorrect because caller_{u,g}id
> >>>>> values are unmapped. At the same time we can't map these fields with an
> >>>>> idmapping as it can break UID/GID-based permission checks logic on the
> >>>>> MDS side. This problem was described with a lot of details at [1], [2].
> >>>>>
> >>>>> [1] https://lore.kernel.org/lkml/CAEivzxfw1fHO2TFA4dx3u23ZKK6Q+EThfzuibrhA3RKM=ZOYLg@mail.gmail.com/
> >>>>> [2] https://lore.kernel.org/all/20220104140414.155198-3-brauner@kernel.org/
> >>>>>
> >>>>> Link: https://github.com/ceph/ceph/pull/52575
> >>>>> Link: https://tracker.ceph.com/issues/62217
> >>>>> Cc: Xiubo Li <xiubli@redhat.com>
> >>>>> Cc: Jeff Layton <jlayton@kernel.org>
> >>>>> Cc: Ilya Dryomov <idryomov@gmail.com>
> >>>>> Cc: ceph-devel@vger.kernel.org
> >>>>> Co-Developed-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>
> >>>>> Signed-off-by: Christian Brauner <brauner@kernel.org>
> >>>>> Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>
> >>>>> ---
> >>>>> v7:
> >>>>>         - reworked to use two new fields for owner UID/GID (https://github.com/ceph/ceph/pull/52575)
> >>>>> v8:
> >>>>>         - properly handled case when old MDS used with new kernel client
> >>>>> ---
> >>>>>     fs/ceph/mds_client.c         | 47 +++++++++++++++++++++++++++++++++---
> >>>>>     fs/ceph/mds_client.h         |  5 +++-
> >>>>>     include/linux/ceph/ceph_fs.h |  5 +++-
> >>>>>     3 files changed, 52 insertions(+), 5 deletions(-)
> >>>>>
> >>>>> diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
> >>>>> index 8829f55103da..41e4bf3811c4 100644
> >>>>> --- a/fs/ceph/mds_client.c
> >>>>> +++ b/fs/ceph/mds_client.c
> >>>>> @@ -2902,6 +2902,17 @@ static void encode_mclientrequest_tail(void **p, const struct ceph_mds_request *
> >>>>>         }
> >>>>>     }
> >>>>>
> >>>>> +static inline u16 mds_supported_head_version(struct ceph_mds_session *session)
> >>>>> +{
> >>>>> +     if (!test_bit(CEPHFS_FEATURE_32BITS_RETRY_FWD, &session->s_features))
> >>>>> +             return 1;
> >>>>> +
> >>>>> +     if (!test_bit(CEPHFS_FEATURE_HAS_OWNER_UIDGID, &session->s_features))
> >>>>> +             return 2;
> >>>>> +
> >>>>> +     return CEPH_MDS_REQUEST_HEAD_VERSION;
> >>>>> +}
> >>>>> +
> >>>>>     static struct ceph_mds_request_head_legacy *
> >>>>>     find_legacy_request_head(void *p, u64 features)
> >>>>>     {
> >>>>> @@ -2923,6 +2934,7 @@ static struct ceph_msg *create_request_message(struct ceph_mds_session *session,
> >>>>>     {
> >>>>>         int mds = session->s_mds;
> >>>>>         struct ceph_mds_client *mdsc = session->s_mdsc;
> >>>>> +     struct ceph_client *cl = mdsc->fsc->client;
> >>>>>         struct ceph_msg *msg;
> >>>>>         struct ceph_mds_request_head_legacy *lhead;
> >>>>>         const char *path1 = NULL;
> >>>>> @@ -2936,7 +2948,7 @@ static struct ceph_msg *create_request_message(struct ceph_mds_session *session,
> >>>>>         void *p, *end;
> >>>>>         int ret;
> >>>>>         bool legacy = !(session->s_con.peer_features & CEPH_FEATURE_FS_BTIME);
> >>>>> -     bool old_version = !test_bit(CEPHFS_FEATURE_32BITS_RETRY_FWD, &session->s_features);
> >>>>> +     u16 request_head_version = mds_supported_head_version(session);
> >>>>>
> >>>>>         ret = set_request_path_attr(mdsc, req->r_inode, req->r_dentry,
> >>>>>                               req->r_parent, req->r_path1, req->r_ino1.ino,
> >>>>> @@ -2977,8 +2989,10 @@ static struct ceph_msg *create_request_message(struct ceph_mds_session *session,
> >>>>>          */
> >>>>>         if (legacy)
> >>>>>                 len = sizeof(struct ceph_mds_request_head_legacy);
> >>>>> -     else if (old_version)
> >>>>> +     else if (request_head_version == 1)
> >>>>>                 len = sizeof(struct ceph_mds_request_head_old);
> >>>>> +     else if (request_head_version == 2)
> >>>>> +             len = offsetofend(struct ceph_mds_request_head, ext_num_fwd);
> >>>>>         else
> >>>>>                 len = sizeof(struct ceph_mds_request_head);
> >>>>>
> >>>>> @@ -3028,6 +3042,16 @@ static struct ceph_msg *create_request_message(struct ceph_mds_session *session,
> >>>>>         lhead = find_legacy_request_head(msg->front.iov_base,
> >>>>>                                          session->s_con.peer_features);
> >>>>>
> >>>>> +     if ((req->r_mnt_idmap != &nop_mnt_idmap) &&
> >>>>> +         !test_bit(CEPHFS_FEATURE_HAS_OWNER_UIDGID, &session->s_features)) {
> >>>>> +             pr_err_ratelimited_client(cl,
> >>>>> +                     "idmapped mount is used and CEPHFS_FEATURE_HAS_OWNER_UIDGID"
> >>>>> +                     " is not supported by MDS. Fail request with -EIO.\n");
> >>>>> +
> >>>>> +             ret = -EIO;
> >>>>> +             goto out_err;
> >>>>> +     }
> >>>>> +
> >>>>>         /*
> >>>>>          * The ceph_mds_request_head_legacy didn't contain a version field, and
> >>>>>          * one was added when we moved the message version from 3->4.
> >>>>> @@ -3035,17 +3059,34 @@ static struct ceph_msg *create_request_message(struct ceph_mds_session *session,
> >>>>>         if (legacy) {
> >>>>>                 msg->hdr.version = cpu_to_le16(3);
> >>>>>                 p = msg->front.iov_base + sizeof(*lhead);
> >>>>> -     } else if (old_version) {
> >>>>> +     } else if (request_head_version == 1) {
> >>>>>                 struct ceph_mds_request_head_old *ohead = msg->front.iov_base;
> >>>>>
> >>>>>                 msg->hdr.version = cpu_to_le16(4);
> >>>>>                 ohead->version = cpu_to_le16(1);
> >>>>>                 p = msg->front.iov_base + sizeof(*ohead);
> >>>>> +     } else if (request_head_version == 2) {
> >>>>> +             struct ceph_mds_request_head *nhead = msg->front.iov_base;
> >>>>> +
> >>>>> +             msg->hdr.version = cpu_to_le16(6);
> >>>>> +             nhead->version = cpu_to_le16(2);
> >>>>> +
> >>>>> +             p = msg->front.iov_base + offsetofend(struct ceph_mds_request_head, ext_num_fwd);
> >>>>>         } else {
> >>>>>                 struct ceph_mds_request_head *nhead = msg->front.iov_base;
> >>>>> +             kuid_t owner_fsuid;
> >>>>> +             kgid_t owner_fsgid;
> >>>>>
> >>>>>                 msg->hdr.version = cpu_to_le16(6);
> >>>>>                 nhead->version = cpu_to_le16(CEPH_MDS_REQUEST_HEAD_VERSION);
> >>>>> +             nhead->struct_len = sizeof(struct ceph_mds_request_head);
> >>>>> +
> >>>>> +             owner_fsuid = from_vfsuid(req->r_mnt_idmap, &init_user_ns,
> >>>>> +                                       VFSUIDT_INIT(req->r_cred->fsuid));
> >>>>> +             owner_fsgid = from_vfsgid(req->r_mnt_idmap, &init_user_ns,
> >>>>> +                                       VFSGIDT_INIT(req->r_cred->fsgid));
> >>>>> +             nhead->owner_uid = cpu_to_le32(from_kuid(&init_user_ns, owner_fsuid));
> >>>>> +             nhead->owner_gid = cpu_to_le32(from_kgid(&init_user_ns, owner_fsgid));
> >>>>>                 p = msg->front.iov_base + sizeof(*nhead);
> >>>>>         }
> >>>>>
> >>>>> diff --git a/fs/ceph/mds_client.h b/fs/ceph/mds_client.h
> >>>>> index e3bbf3ba8ee8..8f683e8203bd 100644
> >>>>> --- a/fs/ceph/mds_client.h
> >>>>> +++ b/fs/ceph/mds_client.h
> >>>>> @@ -33,8 +33,10 @@ enum ceph_feature_type {
> >>>>>         CEPHFS_FEATURE_NOTIFY_SESSION_STATE,
> >>>>>         CEPHFS_FEATURE_OP_GETVXATTR,
> >>>>>         CEPHFS_FEATURE_32BITS_RETRY_FWD,
> >>>>> +     CEPHFS_FEATURE_NEW_SNAPREALM_INFO,
> >>>>> +     CEPHFS_FEATURE_HAS_OWNER_UIDGID,
> >>>>>
> >>>>> -     CEPHFS_FEATURE_MAX = CEPHFS_FEATURE_32BITS_RETRY_FWD,
> >>>>> +     CEPHFS_FEATURE_MAX = CEPHFS_FEATURE_HAS_OWNER_UIDGID,
> >>>>>     };
> >>>>>
> >>>>>     #define CEPHFS_FEATURES_CLIENT_SUPPORTED {  \
> >>>>> @@ -49,6 +51,7 @@ enum ceph_feature_type {
> >>>>>         CEPHFS_FEATURE_NOTIFY_SESSION_STATE,    \
> >>>>>         CEPHFS_FEATURE_OP_GETVXATTR,            \
> >>>>>         CEPHFS_FEATURE_32BITS_RETRY_FWD,        \
> >>>>> +     CEPHFS_FEATURE_HAS_OWNER_UIDGID,        \
> >>>>>     }
> >>>>>
> >>>>>     /*
> >>>>> diff --git a/include/linux/ceph/ceph_fs.h b/include/linux/ceph/ceph_fs.h
> >>>>> index 5f2301ee88bc..b91699b08f26 100644
> >>>>> --- a/include/linux/ceph/ceph_fs.h
> >>>>> +++ b/include/linux/ceph/ceph_fs.h
> >>>>> @@ -499,7 +499,7 @@ struct ceph_mds_request_head_legacy {
> >>>>>         union ceph_mds_request_args args;
> >>>>>     } __attribute__ ((packed));
> >>>>>
> >>>>> -#define CEPH_MDS_REQUEST_HEAD_VERSION  2
> >>>>> +#define CEPH_MDS_REQUEST_HEAD_VERSION  3
> >>>>>
> >>>>>     struct ceph_mds_request_head_old {
> >>>>>         __le16 version;                /* struct version */
> >>>>> @@ -530,6 +530,9 @@ struct ceph_mds_request_head {
> >>>>>
> >>>>>         __le32 ext_num_retry;          /* new count retry attempts */
> >>>>>         __le32 ext_num_fwd;            /* new count fwd attempts */
> >>>>> +
> >>>>> +     __le32 struct_len;             /* to store size of struct ceph_mds_request_head */
> >>>>> +     __le32 owner_uid, owner_gid;   /* used for OPs which create inodes */
> >>>> Let's also initialize them to -1 for all the other requests as we do in
> >>>> your PR.
> >>> They are always initialized already. As you can see from the code we
> >>> don't have any extra conditions
> >>> on filling these fields. We always fill them with an appropriate
> >>> UID/GID. If mount is not idmapped then it's just == caller_uid/gid,
> >>> if mount idmapped then it's idmapped caller_uid/gid.
> >> Then in kclient all the request will always initialized the
> >> 'owner_{uid/gid}' with 'caller_{uid/gid}'. While in userspace libcephfs
> >> it will only set them for 'create/mknod/mkdir/symlink` instead.
> >>
> >> I'd prefer to make them consistent, which is what I am still focusing
> >> on, to make them easier to read and comparing when troubles hooting.
> > Dear Xiubo,
> >
> > Sure, I will do it.
> >
> > Couldn't you please review all the rest of the patches before I fix
> > this particular thing?
> > It will allow me to fix and send -v10 with all required fixes
> > incorporated in it.
>
> I have gone through them all and they LGTM.

Thanks!

Kind regards,
Alex

>
> Thanks
>
> - Xiubo
>
>
> > Kind regards,
> > Alex
> >
> >> Thanks
> >>
> >> - Xiubo
> >>
> >>> Kind regards,
> >>> Alex
> >>>
> >>>> Thanks
> >>>>
> >>>> - Xiubo
> >>>>
> >>>>
> >>>>
> >>>>>     } __attribute__ ((packed));
> >>>>>
> >>>>>     /* cap/lease release record */
>
  

On Mon, Aug 7, 2023 at 12:28 PM Xiubo Li <xiubli@redhat.com> wrote:
>
>
> On 8/7/23 14:51, Aleksandr Mikhalitsyn wrote:
> > On Mon, Aug 7, 2023 at 3:25 AM Xiubo Li <xiubli@redhat.com> wrote:
> >>
> >> On 8/4/23 16:48, Alexander Mikhalitsyn wrote:
> >>> From: Christian Brauner <brauner@kernel.org>
> >>>
> >>> Inode operations that create a new filesystem object such as ->mknod,
> >>> ->create, ->mkdir() and others don't take a {g,u}id argument explicitly.
> >>> Instead the caller's fs{g,u}id is used for the {g,u}id of the new
> >>> filesystem object.
> >>>
> >>> In order to ensure that the correct {g,u}id is used map the caller's
> >>> fs{g,u}id for creation requests. This doesn't require complex changes.
> >>> It suffices to pass in the relevant idmapping recorded in the request
> >>> message. If this request message was triggered from an inode operation
> >>> that creates filesystem objects it will have passed down the relevant
> >>> idmaping. If this is a request message that was triggered from an inode
> >>> operation that doens't need to take idmappings into account the initial
> >>> idmapping is passed down which is an identity mapping.
> >>>
> >>> This change uses a new cephfs protocol extension CEPHFS_FEATURE_HAS_OWNER_UIDGID
> >>> which adds two new fields (owner_{u,g}id) to the request head structure.
> >>> So, we need to ensure that MDS supports it otherwise we need to fail
> >>> any IO that comes through an idmapped mount because we can't process it
> >>> in a proper way. MDS server without such an extension will use caller_{u,g}id
> >>> fields to set a new inode owner UID/GID which is incorrect because caller_{u,g}id
> >>> values are unmapped. At the same time we can't map these fields with an
> >>> idmapping as it can break UID/GID-based permission checks logic on the
> >>> MDS side. This problem was described with a lot of details at [1], [2].
> >>>
> >>> [1] https://lore.kernel.org/lkml/CAEivzxfw1fHO2TFA4dx3u23ZKK6Q+EThfzuibrhA3RKM=ZOYLg@mail.gmail.com/
> >>> [2] https://lore.kernel.org/all/20220104140414.155198-3-brauner@kernel.org/
> >>>
> >>> Link: https://github.com/ceph/ceph/pull/52575
> >>> Link: https://tracker.ceph.com/issues/62217
> >>> Cc: Xiubo Li <xiubli@redhat.com>
> >>> Cc: Jeff Layton <jlayton@kernel.org>
> >>> Cc: Ilya Dryomov <idryomov@gmail.com>
> >>> Cc: ceph-devel@vger.kernel.org
> >>> Co-Developed-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>
> >>> Signed-off-by: Christian Brauner <brauner@kernel.org>
> >>> Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>
> >>> ---
> >>> v7:
> >>>        - reworked to use two new fields for owner UID/GID (https://github.com/ceph/ceph/pull/52575)
> >>> v8:
> >>>        - properly handled case when old MDS used with new kernel client
> >>> ---
> >>>    fs/ceph/mds_client.c         | 47 +++++++++++++++++++++++++++++++++---
> >>>    fs/ceph/mds_client.h         |  5 +++-
> >>>    include/linux/ceph/ceph_fs.h |  5 +++-
> >>>    3 files changed, 52 insertions(+), 5 deletions(-)
> >>>
> >>> diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
> >>> index 8829f55103da..41e4bf3811c4 100644
> >>> --- a/fs/ceph/mds_client.c
> >>> +++ b/fs/ceph/mds_client.c
> >>> @@ -2902,6 +2902,17 @@ static void encode_mclientrequest_tail(void **p, const struct ceph_mds_request *
> >>>        }
> >>>    }
> >>>
> >>> +static inline u16 mds_supported_head_version(struct ceph_mds_session *session)
> >>> +{
> >>> +     if (!test_bit(CEPHFS_FEATURE_32BITS_RETRY_FWD, &session->s_features))
> >>> +             return 1;
> >>> +
> >>> +     if (!test_bit(CEPHFS_FEATURE_HAS_OWNER_UIDGID, &session->s_features))
> >>> +             return 2;
> >>> +
> >>> +     return CEPH_MDS_REQUEST_HEAD_VERSION;
> >>> +}
> >>> +
> >>>    static struct ceph_mds_request_head_legacy *
> >>>    find_legacy_request_head(void *p, u64 features)
> >>>    {
> >>> @@ -2923,6 +2934,7 @@ static struct ceph_msg *create_request_message(struct ceph_mds_session *session,
> >>>    {
> >>>        int mds = session->s_mds;
> >>>        struct ceph_mds_client *mdsc = session->s_mdsc;
> >>> +     struct ceph_client *cl = mdsc->fsc->client;
> >>>        struct ceph_msg *msg;
> >>>        struct ceph_mds_request_head_legacy *lhead;
> >>>        const char *path1 = NULL;
> >>> @@ -2936,7 +2948,7 @@ static struct ceph_msg *create_request_message(struct ceph_mds_session *session,
> >>>        void *p, *end;
> >>>        int ret;
> >>>        bool legacy = !(session->s_con.peer_features & CEPH_FEATURE_FS_BTIME);
> >>> -     bool old_version = !test_bit(CEPHFS_FEATURE_32BITS_RETRY_FWD, &session->s_features);
> >>> +     u16 request_head_version = mds_supported_head_version(session);
> >>>
> >>>        ret = set_request_path_attr(mdsc, req->r_inode, req->r_dentry,
> >>>                              req->r_parent, req->r_path1, req->r_ino1.ino,
> >>> @@ -2977,8 +2989,10 @@ static struct ceph_msg *create_request_message(struct ceph_mds_session *session,
> >>>         */
> >>>        if (legacy)
> >>>                len = sizeof(struct ceph_mds_request_head_legacy);
> >>> -     else if (old_version)
> >>> +     else if (request_head_version == 1)
> >>>                len = sizeof(struct ceph_mds_request_head_old);
> >>> +     else if (request_head_version == 2)
> >>> +             len = offsetofend(struct ceph_mds_request_head, ext_num_fwd);
> >>>        else
> >>>                len = sizeof(struct ceph_mds_request_head);
> >>>
> >>> @@ -3028,6 +3042,16 @@ static struct ceph_msg *create_request_message(struct ceph_mds_session *session,
> >>>        lhead = find_legacy_request_head(msg->front.iov_base,
> >>>                                         session->s_con.peer_features);
> >>>
> >>> +     if ((req->r_mnt_idmap != &nop_mnt_idmap) &&
> >>> +         !test_bit(CEPHFS_FEATURE_HAS_OWNER_UIDGID, &session->s_features)) {
> >>> +             pr_err_ratelimited_client(cl,
> >>> +                     "idmapped mount is used and CEPHFS_FEATURE_HAS_OWNER_UIDGID"
> >>> +                     " is not supported by MDS. Fail request with -EIO.\n");
> >>> +
> >>> +             ret = -EIO;
> >>> +             goto out_err;
> >>> +     }
> >>> +
> >>>        /*
> >>>         * The ceph_mds_request_head_legacy didn't contain a version field, and
> >>>         * one was added when we moved the message version from 3->4.
> >>> @@ -3035,17 +3059,34 @@ static struct ceph_msg *create_request_message(struct ceph_mds_session *session,
> >>>        if (legacy) {
> >>>                msg->hdr.version = cpu_to_le16(3);
> >>>                p = msg->front.iov_base + sizeof(*lhead);
> >>> -     } else if (old_version) {
> >>> +     } else if (request_head_version == 1) {
> >>>                struct ceph_mds_request_head_old *ohead = msg->front.iov_base;
> >>>
> >>>                msg->hdr.version = cpu_to_le16(4);
> >>>                ohead->version = cpu_to_le16(1);
> >>>                p = msg->front.iov_base + sizeof(*ohead);
> >>> +     } else if (request_head_version == 2) {
> >>> +             struct ceph_mds_request_head *nhead = msg->front.iov_base;
> >>> +
> >>> +             msg->hdr.version = cpu_to_le16(6);
> >>> +             nhead->version = cpu_to_le16(2);
> >>> +
> >>> +             p = msg->front.iov_base + offsetofend(struct ceph_mds_request_head, ext_num_fwd);
> >>>        } else {
> >>>                struct ceph_mds_request_head *nhead = msg->front.iov_base;
> >>> +             kuid_t owner_fsuid;
> >>> +             kgid_t owner_fsgid;
> >>>
> >>>                msg->hdr.version = cpu_to_le16(6);
> >>>                nhead->version = cpu_to_le16(CEPH_MDS_REQUEST_HEAD_VERSION);
> >>> +             nhead->struct_len = sizeof(struct ceph_mds_request_head);
> >>> +
> >>> +             owner_fsuid = from_vfsuid(req->r_mnt_idmap, &init_user_ns,
> >>> +                                       VFSUIDT_INIT(req->r_cred->fsuid));
> >>> +             owner_fsgid = from_vfsgid(req->r_mnt_idmap, &init_user_ns,
> >>> +                                       VFSGIDT_INIT(req->r_cred->fsgid));
> >>> +             nhead->owner_uid = cpu_to_le32(from_kuid(&init_user_ns, owner_fsuid));
> >>> +             nhead->owner_gid = cpu_to_le32(from_kgid(&init_user_ns, owner_fsgid));
> >>>                p = msg->front.iov_base + sizeof(*nhead);
> >>>        }
> >>>
> >>> diff --git a/fs/ceph/mds_client.h b/fs/ceph/mds_client.h
> >>> index e3bbf3ba8ee8..8f683e8203bd 100644
> >>> --- a/fs/ceph/mds_client.h
> >>> +++ b/fs/ceph/mds_client.h
> >>> @@ -33,8 +33,10 @@ enum ceph_feature_type {
> >>>        CEPHFS_FEATURE_NOTIFY_SESSION_STATE,
> >>>        CEPHFS_FEATURE_OP_GETVXATTR,
> >>>        CEPHFS_FEATURE_32BITS_RETRY_FWD,
> >>> +     CEPHFS_FEATURE_NEW_SNAPREALM_INFO,
> >>> +     CEPHFS_FEATURE_HAS_OWNER_UIDGID,
> >>>
> >>> -     CEPHFS_FEATURE_MAX = CEPHFS_FEATURE_32BITS_RETRY_FWD,
> >>> +     CEPHFS_FEATURE_MAX = CEPHFS_FEATURE_HAS_OWNER_UIDGID,
> >>>    };
> >>>
> >>>    #define CEPHFS_FEATURES_CLIENT_SUPPORTED {  \
> >>> @@ -49,6 +51,7 @@ enum ceph_feature_type {
> >>>        CEPHFS_FEATURE_NOTIFY_SESSION_STATE,    \
> >>>        CEPHFS_FEATURE_OP_GETVXATTR,            \
> >>>        CEPHFS_FEATURE_32BITS_RETRY_FWD,        \
> >>> +     CEPHFS_FEATURE_HAS_OWNER_UIDGID,        \
> >>>    }
> >>>
> >>>    /*
> >>> diff --git a/include/linux/ceph/ceph_fs.h b/include/linux/ceph/ceph_fs.h
> >>> index 5f2301ee88bc..b91699b08f26 100644
> >>> --- a/include/linux/ceph/ceph_fs.h
> >>> +++ b/include/linux/ceph/ceph_fs.h
> >>> @@ -499,7 +499,7 @@ struct ceph_mds_request_head_legacy {
> >>>        union ceph_mds_request_args args;
> >>>    } __attribute__ ((packed));
> >>>
> >>> -#define CEPH_MDS_REQUEST_HEAD_VERSION  2
> >>> +#define CEPH_MDS_REQUEST_HEAD_VERSION  3
> >>>
> >>>    struct ceph_mds_request_head_old {
> >>>        __le16 version;                /* struct version */
> >>> @@ -530,6 +530,9 @@ struct ceph_mds_request_head {
> >>>
> >>>        __le32 ext_num_retry;          /* new count retry attempts */
> >>>        __le32 ext_num_fwd;            /* new count fwd attempts */
> >>> +
> >>> +     __le32 struct_len;             /* to store size of struct ceph_mds_request_head */
> >>> +     __le32 owner_uid, owner_gid;   /* used for OPs which create inodes */
> >> Let's also initialize them to -1 for all the other requests as we do in
> >> your PR.
> > They are always initialized already. As you can see from the code we
> > don't have any extra conditions
> > on filling these fields. We always fill them with an appropriate
> > UID/GID. If mount is not idmapped then it's just == caller_uid/gid,
> > if mount idmapped then it's idmapped caller_uid/gid.
>
> Then in kclient all the request will always initialized the
> 'owner_{uid/gid}' with 'caller_{uid/gid}'. While in userspace libcephfs
> it will only set them for 'create/mknod/mkdir/symlink` instead.
>
> I'd prefer to make them consistent, which is what I am still focusing
> on, to make them easier to read and comparing when troubles hooting.

Have fixed:
https://github.com/mihalicyn/linux/commit/5a5b590ca5aa9ec81d68ff60d77ea54fc86bf33a

Also have added appropriate checks in mkdir/atomic_open:
https://github.com/mihalicyn/linux/commit/bc1fa68f7143a58af8c181bbfab64edf0397dca5
https://github.com/mihalicyn/linux/commit/30e21387063710a10cdca15a5d840fcf8e1e6ccd

Will send v10 soon.

Kind regards,
Alex

>
> Thanks
>
> - Xiubo
>
> > Kind regards,
> > Alex
> >
> >> Thanks
> >>
> >> - Xiubo
> >>
> >>
> >>
> >>>    } __attribute__ ((packed));
> >>>
> >>>    /* cap/lease release record */
>