On Fri, Aug 4, 2023 at 4:26 AM Xiubo Li <xiubli@xxxxxxxxxx> wrote: > > > On 8/3/23 21:59, Alexander Mikhalitsyn wrote: > > From: Christian Brauner <brauner@xxxxxxxxxx> > > > > 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@xxxxxxxxxxxxxx/ > > [2] https://lore.kernel.org/all/20220104140414.155198-3-brauner@xxxxxxxxxx/ > > > > https://github.com/ceph/ceph/pull/52575 > > https://tracker.ceph.com/issues/62217 > > > > Cc: Xiubo Li <xiubli@xxxxxxxxxx> > > Cc: Jeff Layton <jlayton@xxxxxxxxxx> > > Cc: Ilya Dryomov <idryomov@xxxxxxxxx> > > Cc: ceph-devel@xxxxxxxxxxxxxxx > > Co-Developed-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@xxxxxxxxxxxxx> > > Signed-off-by: Christian Brauner <brauner@xxxxxxxxxx> > > Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@xxxxxxxxxxxxx> > > --- > > 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 | 46 +++++++++++++++++++++++++++++++++--- > > fs/ceph/mds_client.h | 5 +++- > > include/linux/ceph/ceph_fs.h | 4 +++- > > 3 files changed, 50 insertions(+), 5 deletions(-) > > > > diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c > > index 8829f55103da..7d3106d3b726 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); > > > > This is not what we suppose to. If we do this again and again when > adding new members it will make the code very complicated to maintain. > > Once the CEPHFS_FEATURE_32BITS_RETRY_FWD has been supported the ceph > should correctly decode it and if CEPHFS_FEATURE_HAS_OWNER_UIDGID is not > supported the decoder should skip it directly. I thought that too. But it doesn't work. Just try - take kernel client testing branch, and then add a new field to the struct ceph_mds_request_head. Compile and try to mount. It will stop to work and on the MDS side you will see something like: 2023-08-03T13:15:40.871+0200 7fe64ef5e640 10 mds.c ms_handle_accept v1:192.168.2.136:0/49354629 con 0x563962206880 session 0x563967054000 2023-08-03T13:15:40.871+0200 7fe650f62640 -1 failed to decode message of type 24 v6: End of buffer [buffer:2] 2023-08-03T13:15:40.871+0200 7fe650f62640 1 dump: 00000000 03 00 01 00 00 00 00 00 00 00 10 00 00 00 00 00 |................| 00000010 00 00 00 00 00 00 01 01 00 00 00 00 00 00 00 00 |................| 00000020 00 00 00 00 00 00 00 00 00 00 01 00 00 00 00 00 |................| 00000030 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| * 00000070 00 00 01 01 00 00 00 00 00 00 00 00 00 00 00 01 |................| 00000080 00 00 00 00 00 00 00 00 00 00 00 00 5b 8c cb 64 |............[..d| 00000090 64 78 11 13 01 00 00 00 00 00 00 00 00 00 00 00 |dx..............| 000000a0 00 00 00 00 00 00 00 00 00 00 00 00 |............| 000000ac As I understand, the MDS side is not ready to see struct ceph_mds_request_head bigger in size than supported. > > Is the MDS side buggy ? Why you last version didn't work ? > > Thanks > > - Xiubo > > > @@ -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 +3059,33 @@ 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); > > + > > + 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..6eb83a51341c 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 +530,8 @@ struct ceph_mds_request_head { > > > > __le32 ext_num_retry; /* new count retry attempts */ > > __le32 ext_num_fwd; /* new count fwd attempts */ > > + > > + __le32 owner_uid, owner_gid; /* used for OPs which create inodes */ > > } __attribute__ ((packed)); > > > > /* cap/lease release record */ >