Re: [RFC PATCH v11 08/51] ceph: add support for fscrypt_auth/fscrypt_file to cap messages

Jeff Layton
2022-03-23T16:56:02Z

On Tue, 2022-03-22 at 10:12 -0400, Jeff Layton wrote:
> Add support for new version 12 cap messages that carry the new
> fscrypt_auth and fscrypt_file fields from the inode.
>
> Signed-off-by: Jeff Layton <jlayton@kernel.org>
> ---
> fs/ceph/caps.c | 76 +++++++++++++++++++++++++++++++++++++++++---------
> 1 file changed, 63 insertions(+), 13 deletions(-)
>
> diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
> index 7d8ef67a1032..b0b7688331b4 100644
> --- a/fs/ceph/caps.c
> +++ b/fs/ceph/caps.c
> @@ -13,6 +13,7 @@
> #include "super.h"
> #include "mds_client.h"
> #include "cache.h"
> +#include "crypto.h"
> #include <linux/ceph/decode.h>
> #include <linux/ceph/messenger.h>
>
> @@ -1214,15 +1215,12 @@ struct cap_msg_args {
> umode_t mode;
> bool inline_data;
> bool wake;
> + u32 fscrypt_auth_len;
> + u32 fscrypt_file_len;
> + u8 fscrypt_auth[sizeof(struct ceph_fscrypt_auth)]; // for context
> + u8 fscrypt_file[sizeof(u64)]; // for size
> };
>
> -/*
> - * cap struct size + flock buffer size + inline version + inline data size +
> - * osd_epoch_barrier + oldest_flush_tid
> - */
> -#define CAP_MSG_SIZE (sizeof(struct ceph_mds_caps) + \
> - 4 + 8 + 4 + 4 + 8 + 4 + 4 + 4 + 8 + 8 + 4)
> -
> /* Marshal up the cap msg to the MDS */
> static void encode_cap_msg(struct ceph_msg *msg, struct cap_msg_args *arg)
> {
> @@ -1238,7 +1236,7 @@ static void encode_cap_msg(struct ceph_msg *msg, struct cap_msg_args *arg)
> arg->size, arg->max_size, arg->xattr_version,
> arg->xattr_buf ? (int)arg->xattr_buf->vec.iov_len : 0);
>
> - msg->hdr.version = cpu_to_le16(10);
> + msg->hdr.version = cpu_to_le16(12);
> msg->hdr.tid = cpu_to_le64(arg->flush_tid);
>
> fc = msg->front.iov_base;
> @@ -1309,6 +1307,21 @@ static void encode_cap_msg(struct ceph_msg *msg, struct cap_msg_args *arg)
>
> /* Advisory flags (version 10) */
> ceph_encode_32(&p, arg->flags);
> +
> + /* dirstats (version 11) - these are r/o on the client */
> + ceph_encode_64(&p, 0);
> + ceph_encode_64(&p, 0);
> +
> +#if IS_ENABLED(CONFIG_FS_ENCRYPTION)
> + /* fscrypt_auth and fscrypt_file (version 12) */
> + ceph_encode_32(&p, arg->fscrypt_auth_len);
> + ceph_encode_copy(&p, arg->fscrypt_auth, arg->fscrypt_auth_len);
> + ceph_encode_32(&p, arg->fscrypt_file_len);
> + ceph_encode_copy(&p, arg->fscrypt_file, arg->fscrypt_file_len);
> +#else /* CONFIG_FS_ENCRYPTION */
> + ceph_encode_32(&p, 0);
> + ceph_encode_32(&p, 0);
> +#endif /* CONFIG_FS_ENCRYPTION */
> }
>
> /*
> @@ -1430,8 +1443,37 @@ static void __prep_cap(struct cap_msg_args *arg, struct ceph_cap *cap,
> }
> }
> arg->flags = flags;
> +#if IS_ENABLED(CONFIG_FS_ENCRYPTION)
> + if (ci->fscrypt_auth_len &&
> + WARN_ON_ONCE(ci->fscrypt_auth_len != sizeof(struct ceph_fscrypt_auth))) {

The above WARN_ON_ONCE is too strict, and causes the client to reject v1
fscrypt contexts (as well as throw the warning). That should be a ">"
instead. I've fixed this in my tree and pushed the fix into wip-fscrypt.

> + /* Don't set this if it isn't right size */
> + arg->fscrypt_auth_len = 0;
> + } else {
> + arg->fscrypt_auth_len = ci->fscrypt_auth_len;
> + memcpy(arg->fscrypt_auth, ci->fscrypt_auth,
> + min_t(size_t, ci->fscrypt_auth_len, sizeof(arg->fscrypt_auth)));
> + }
> + /* FIXME: use this to track "real" size */
> + arg->fscrypt_file_len = 0;
> +#endif /* CONFIG_FS_ENCRYPTION */
> }
>
> +#define CAP_MSG_FIXED_FIELDS (sizeof(struct ceph_mds_caps) + \
> + 4 + 8 + 4 + 4 + 8 + 4 + 4 + 4 + 8 + 8 + 4 + 8 + 8 + 4 + 4)
> +
> +#if IS_ENABLED(CONFIG_FS_ENCRYPTION)
> +static inline int cap_msg_size(struct cap_msg_args *arg)
> +{
> + return CAP_MSG_FIXED_FIELDS + arg->fscrypt_auth_len +
> + arg->fscrypt_file_len;
> +}
> +#else
> +static inline int cap_msg_size(struct cap_msg_args *arg)
> +{
> + return CAP_MSG_FIXED_FIELDS;
> +}
> +#endif /* CONFIG_FS_ENCRYPTION */
> +
> /*
> * Send a cap msg on the given inode.
> *
> @@ -1442,7 +1484,7 @@ static void __send_cap(struct cap_msg_args *arg, struct ceph_inode_info *ci)
> struct ceph_msg *msg;
> struct inode *inode = &ci->vfs_inode;
>
> - msg = ceph_msg_new(CEPH_MSG_CLIENT_CAPS, CAP_MSG_SIZE, GFP_NOFS, false);
> + msg = ceph_msg_new(CEPH_MSG_CLIENT_CAPS, cap_msg_size(arg), GFP_NOFS, false);
> if (!msg) {
> pr_err("error allocating cap msg: ino (%llx.%llx) flushing %s tid %llu, requeuing cap.\n",
> ceph_vinop(inode), ceph_cap_string(arg->dirty),
> @@ -1468,10 +1510,6 @@ static inline int __send_flush_snap(struct inode *inode,
> struct cap_msg_args arg;
> struct ceph_msg *msg;
>
> - msg = ceph_msg_new(CEPH_MSG_CLIENT_CAPS, CAP_MSG_SIZE, GFP_NOFS, false);
> - if (!msg)
> - return -ENOMEM;
> -
> arg.session = session;
> arg.ino = ceph_vino(inode).ino;
> arg.cid = 0;
> @@ -1509,6 +1547,18 @@ static inline int __send_flush_snap(struct inode *inode,
> arg.flags = 0;
> arg.wake = false;
>
> + /*
> + * No fscrypt_auth changes from a capsnap. It will need
> + * to update fscrypt_file on size changes (TODO).
> + */
> + arg.fscrypt_auth_len = 0;
> + arg.fscrypt_file_len = 0;
> +
> + msg = ceph_msg_new(CEPH_MSG_CLIENT_CAPS, cap_msg_size(&arg),
> + GFP_NOFS, false);
> + if (!msg)
> + return -ENOMEM;
> +
> encode_cap_msg(msg, &arg);
> ceph_con_send(&arg.session->s_con, msg);
> return 0;

--
Jeff Layton <jlayton@kernel.org>