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From:   Jeff Layton <jlayton@kernel.org>
To:     idryomov@gmail.com, xiubli@redhat.com
Cc:     ceph-devel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
        linux-fscrypt@vger.kernel.org, linux-kernel@vger.kernel.org,
        lhenriques@suse.de
Subject: [RFC PATCH v11 08/51] ceph: add support for fscrypt_auth/fscrypt_file to cap messages
Date:   Tue, 22 Mar 2022 10:12:33 -0400
Message-Id: <20220322141316.41325-9-jlayton@kernel.org>
In-Reply-To: <20220322141316.41325-1-jlayton@kernel.org>
References: <20220322141316.41325-1-jlayton@kernel.org>
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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))) {
+		/* 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;
-- 
2.35.1