1 files changed, 174 insertions, 0 deletions

diff --git a/fs/ceph/mdsmap.c b/fs/ceph/mdsmap.c
new file mode 100644
index 000000000000..c4c498e6dfef
--- /dev/null
+++ b/fs/ceph/mdsmap.c
@@ -0,0 +1,174 @@
+#include "ceph_debug.h"
+
+#include <linux/bug.h>
+#include <linux/err.h>
+#include <linux/random.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+
+#include "mdsmap.h"
+#include "messenger.h"
+#include "decode.h"
+
+#include "super.h"
+
+
+/*
+ * choose a random mds that is "up" (i.e. has a state > 0), or -1.
+ */
+int ceph_mdsmap_get_random_mds(struct ceph_mdsmap *m)
+{
+        int n = 0;
+        int i;
+        char r;
+
+        /* count */
+        for (i = 0; i < m->m_max_mds; i++)
+                if (m->m_info[i].state > 0)
+                        n++;
+        if (n == 0)
+                return -1;
+
+        /* pick */
+        get_random_bytes(&r, 1);
+        n = r % n;
+        i = 0;
+        for (i = 0; n > 0; i++, n--)
+                while (m->m_info[i].state <= 0)
+                        i++;
+
+        return i;
+}
+
+/*
+ * Decode an MDS map
+ *
+ * Ignore any fields we don't care about (there are quite a few of
+ * them).
+ */
+struct ceph_mdsmap *ceph_mdsmap_decode(void **p, void *end)
+{
+        struct ceph_mdsmap *m;
+        const void *start = *p;
+        int i, j, n;
+        int err = -EINVAL;
+        u16 version;
+
+        m = kzalloc(sizeof(*m), GFP_NOFS);
+        if (m == NULL)
+                return ERR_PTR(-ENOMEM);
+
+        ceph_decode_16_safe(p, end, version, bad);
+
+        ceph_decode_need(p, end, 8*sizeof(u32) + sizeof(u64), bad);
+        m->m_epoch = ceph_decode_32(p);
+        m->m_client_epoch = ceph_decode_32(p);
+        m->m_last_failure = ceph_decode_32(p);
+        m->m_root = ceph_decode_32(p);
+        m->m_session_timeout = ceph_decode_32(p);
+        m->m_session_autoclose = ceph_decode_32(p);
+        m->m_max_file_size = ceph_decode_64(p);
+        m->m_max_mds = ceph_decode_32(p);
+
+        m->m_info = kcalloc(m->m_max_mds, sizeof(*m->m_info), GFP_NOFS);
+        if (m->m_info == NULL)
+                goto badmem;
+
+        /* pick out active nodes from mds_info (state > 0) */
+        n = ceph_decode_32(p);
+        for (i = 0; i < n; i++) {
+                u64 global_id;
+                u32 namelen;
+                s32 mds, inc, state;
+                u64 state_seq;
+                u8 infoversion;
+                struct ceph_entity_addr addr;
+                u32 num_export_targets;
+                void *pexport_targets = NULL;
+
+                ceph_decode_need(p, end, sizeof(u64)*2 + 1 + sizeof(u32), bad);
+                global_id = ceph_decode_64(p);
+                infoversion = ceph_decode_8(p);
+                *p += sizeof(u64);
+                namelen = ceph_decode_32(p);  /* skip mds name */
+                *p += namelen;
+
+                ceph_decode_need(p, end,
+                                 4*sizeof(u32) + sizeof(u64) +
+                                 sizeof(addr) + sizeof(struct ceph_timespec),
+                                 bad);
+                mds = ceph_decode_32(p);
+                inc = ceph_decode_32(p);
+                state = ceph_decode_32(p);
+                state_seq = ceph_decode_64(p);
+                ceph_decode_copy(p, &addr, sizeof(addr));
+                ceph_decode_addr(&addr);
+                *p += sizeof(struct ceph_timespec);
+                *p += sizeof(u32);
+                ceph_decode_32_safe(p, end, namelen, bad);
+                *p += namelen;
+                if (infoversion >= 2) {
+                        ceph_decode_32_safe(p, end, num_export_targets, bad);
+                        pexport_targets = *p;
+                        *p += num_export_targets * sizeof(u32);
+                } else {
+                        num_export_targets = 0;
+                }
+
+                dout("mdsmap_decode %d/%d %lld mds%d.%d %s %s\n",
+                     i+1, n, global_id, mds, inc, pr_addr(&addr.in_addr),
+                     ceph_mds_state_name(state));
+                if (mds >= 0 && mds < m->m_max_mds && state > 0) {
+                        m->m_info[mds].global_id = global_id;
+                        m->m_info[mds].state = state;
+                        m->m_info[mds].addr = addr;
+                        m->m_info[mds].num_export_targets = num_export_targets;
+                        if (num_export_targets) {
+                                m->m_info[mds].export_targets =
+                                        kcalloc(num_export_targets, sizeof(u32),
+                                                GFP_NOFS);
+                                for (j = 0; j < num_export_targets; j++)
+                                        m->m_info[mds].export_targets[j] =
+                                               ceph_decode_32(&pexport_targets);
+                        } else {
+                                m->m_info[mds].export_targets = NULL;
+                        }
+                }
+        }
+
+        /* pg_pools */
+        ceph_decode_32_safe(p, end, n, bad);
+        m->m_num_data_pg_pools = n;
+        m->m_data_pg_pools = kcalloc(n, sizeof(u32), GFP_NOFS);
+        if (!m->m_data_pg_pools)
+                goto badmem;
+        ceph_decode_need(p, end, sizeof(u32)*(n+1), bad);
+        for (i = 0; i < n; i++)
+                m->m_data_pg_pools[i] = ceph_decode_32(p);
+        m->m_cas_pg_pool = ceph_decode_32(p);
+
+        /* ok, we don't care about the rest. */
+        dout("mdsmap_decode success epoch %u\n", m->m_epoch);
+        return m;
+
+badmem:
+        err = -ENOMEM;
+bad:
+        pr_err("corrupt mdsmap\n");
+        print_hex_dump(KERN_DEBUG, "mdsmap: ",
+                       DUMP_PREFIX_OFFSET, 16, 1,
+                       start, end - start, true);
+        ceph_mdsmap_destroy(m);
+        return ERR_PTR(-EINVAL);
+}
+
+void ceph_mdsmap_destroy(struct ceph_mdsmap *m)
+{
+        int i;
+
+        for (i = 0; i < m->m_max_mds; i++)
+                kfree(m->m_info[i].export_targets);
+        kfree(m->m_info);
+        kfree(m->m_data_pg_pools);
+        kfree(m);
+}