Messages in this thread | | | Date | Mon, 7 Aug 2023 19:21:42 +0800 | Subject | Re: [PATCH v9 03/12] ceph: handle idmapped mounts in create_request_message() | From | Xiubo Li <> |
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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 */
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