ceph: support cephfs' own feature bits

Signed-off-by: "Yan, Zheng" <zyan@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index 8dbfca0..5b767cf 100644 (file)
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -902,6 +902,27 @@ static struct ceph_msg *create_session_msg(u32 op, u64 seq)
        return msg;
 }
 
+static void encode_supported_features(void **p, void *end)
+{
+       static const unsigned char bits[] = CEPHFS_FEATURES_CLIENT_SUPPORTED;
+       static const size_t count = ARRAY_SIZE(bits);
+
+       if (count > 0) {
+               size_t i;
+               size_t size = ((size_t)bits[count - 1] + 64) / 64 * 8;
+
+               BUG_ON(*p + 4 + size > end);
+               ceph_encode_32(p, size);
+               memset(*p, 0, size);
+               for (i = 0; i < count; i++)
+                       ((unsigned char*)(*p))[i / 8] |= 1 << (bits[i] % 8);
+               *p += size;
+       } else {
+               BUG_ON(*p + 4 > end);
+               ceph_encode_32(p, 0);
+       }
+}
+
 /*
  * session message, specialization for CEPH_SESSION_REQUEST_OPEN
  * to include additional client metadata fields.
@@ -911,11 +932,11 @@ static struct ceph_msg *create_session_open_msg(struct ceph_mds_client *mdsc, u6
        struct ceph_msg *msg;
        struct ceph_mds_session_head *h;
        int i = -1;
-       int metadata_bytes = 0;
+       int extra_bytes = 0;
        int metadata_key_count = 0;
        struct ceph_options *opt = mdsc->fsc->client->options;
        struct ceph_mount_options *fsopt = mdsc->fsc->mount_options;
-       void *p;
+       void *p, *end;
 
        const char* metadata[][2] = {
                {"hostname", mdsc->nodename},
@@ -926,21 +947,26 @@ static struct ceph_msg *create_session_open_msg(struct ceph_mds_client *mdsc, u6
        };
 
        /* Calculate serialized length of metadata */
-       metadata_bytes = 4;  /* map length */
+       extra_bytes = 4;  /* map length */
        for (i = 0; metadata[i][0]; ++i) {
-               metadata_bytes += 8 + strlen(metadata[i][0]) +
+               extra_bytes += 8 + strlen(metadata[i][0]) +
                        strlen(metadata[i][1]);
                metadata_key_count++;
        }
+       /* supported feature */
+       extra_bytes += 4 + 8;
 
        /* Allocate the message */
-       msg = ceph_msg_new(CEPH_MSG_CLIENT_SESSION, sizeof(*h) + metadata_bytes,
+       msg = ceph_msg_new(CEPH_MSG_CLIENT_SESSION, sizeof(*h) + extra_bytes,
                           GFP_NOFS, false);
        if (!msg) {
                pr_err("create_session_msg ENOMEM creating msg\n");
                return NULL;
        }
-       h = msg->front.iov_base;
+       p = msg->front.iov_base;
+       end = p + msg->front.iov_len;
+
+       h = p;
        h->op = cpu_to_le32(CEPH_SESSION_REQUEST_OPEN);
        h->seq = cpu_to_le64(seq);
 
@@ -950,11 +976,11 @@ static struct ceph_msg *create_session_open_msg(struct ceph_mds_client *mdsc, u6
         *
         * ClientSession messages with metadata are v2
         */
-       msg->hdr.version = cpu_to_le16(2);
+       msg->hdr.version = cpu_to_le16(3);
        msg->hdr.compat_version = cpu_to_le16(1);
 
        /* The write pointer, following the session_head structure */
-       p = msg->front.iov_base + sizeof(*h);
+       p += sizeof(*h);
 
        /* Number of entries in the map */
        ceph_encode_32(&p, metadata_key_count);
@@ -972,6 +998,10 @@ static struct ceph_msg *create_session_open_msg(struct ceph_mds_client *mdsc, u6
                p += val_len;
        }
 
+       encode_supported_features(&p, end);
+       msg->front.iov_len = p - msg->front.iov_base;
+       msg->hdr.front_len = cpu_to_le32(msg->front.iov_len);
+
        return msg;
 }
 
@@ -2749,7 +2779,7 @@ static void handle_session(struct ceph_mds_session *session,
        int wake = 0;
 
        /* decode */
-       if (msg->front.iov_len != sizeof(*h))
+       if (msg->front.iov_len < sizeof(*h))
                goto bad;
        op = le32_to_cpu(h->op);
        seq = le64_to_cpu(h->seq);

diff --git a/fs/ceph/mds_client.h b/fs/ceph/mds_client.h
index 80a7523..32fcce0 100644 (file)
--- a/fs/ceph/mds_client.h
+++ b/fs/ceph/mds_client.h
@@ -16,6 +16,18 @@
 #include <linux/ceph/mdsmap.h>
 #include <linux/ceph/auth.h>
 
+/* The first 8 bits are reserved for old ceph releases */
+#define CEPHFS_FEATURE_MIMIC    8
+
+#define CEPHFS_FEATURES_ALL {           \
+  0, 1, 2, 3, 4, 5, 6, 7,              \
+  CEPHFS_FEATURE_MIMIC,                 \
+}
+
+#define CEPHFS_FEATURES_CLIENT_SUPPORTED CEPHFS_FEATURES_ALL
+#define CEPHFS_FEATURES_CLIENT_REQUIRED {}
+
+
 /*
  * Some lock dependencies:
  *