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authorSage Weil <sage@newdream.net>2009-10-06 20:31:09 +0200
committerSage Weil <sage@newdream.net>2009-10-06 20:31:09 +0200
commit2f2dc053404febedc9c273452d9d518fb31fde72 (patch)
tree286ff35153d0b52349e035a69f3f795fdcb0afb6 /fs/ceph/mdsmap.c
parentceph: address space operations (diff)
downloadlinux-2f2dc053404febedc9c273452d9d518fb31fde72.tar.xz
linux-2f2dc053404febedc9c273452d9d518fb31fde72.zip
ceph: MDS client
The MDS (metadata server) client is responsible for submitting requests to the MDS cluster and parsing the response. We decide which MDS to submit each request to based on cached information about the current partition of the directory hierarchy across the cluster. A stateful session is opened with each MDS before we submit requests to it, and a mutex is used to control the ordering of messages within each session. An MDS request may generate two responses. The first indicates the operation was a success and returns any result. A second reply is sent when the operation commits to disk. Note that locking on the MDS ensures that the results of updates are visible only to the updating client before the operation commits. Requests are linked to the containing directory so that an fsync will wait for them to commit. If an MDS fails and/or recovers, we resubmit requests as needed. We also reconnect existing capabilities to a recovering MDS to reestablish that shared session state. Old dentry leases are invalidated. Signed-off-by: Sage Weil <sage@newdream.net>
Diffstat (limited to 'fs/ceph/mdsmap.c')
-rw-r--r--fs/ceph/mdsmap.c166
1 files changed, 166 insertions, 0 deletions
diff --git a/fs/ceph/mdsmap.c b/fs/ceph/mdsmap.c
new file mode 100644
index 000000000000..15913cbeb289
--- /dev/null
+++ b/fs/ceph/mdsmap.c
@@ -0,0 +1,166 @@
+#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;
+ 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);
+ ceph_decode_32(p, 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_64(p, m->m_max_file_size);
+ ceph_decode_32(p, m->m_max_mds);
+
+ 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) */
+ ceph_decode_32(p, n);
+ for (i = 0; i < n; i++) {
+ 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(addr) + 1 + sizeof(u32), bad);
+ *p += sizeof(addr); /* skip addr key */
+ ceph_decode_8(p, infoversion);
+ ceph_decode_32(p, namelen); /* skip mds name */
+ *p += namelen;
+
+ ceph_decode_need(p, end,
+ 5*sizeof(u32) + sizeof(u64) +
+ sizeof(addr) + sizeof(struct ceph_timespec),
+ bad);
+ ceph_decode_32(p, mds);
+ ceph_decode_32(p, inc);
+ ceph_decode_32(p, state);
+ ceph_decode_64(p, state_seq);
+ ceph_decode_copy(p, &addr, sizeof(addr));
+ *p += sizeof(struct ceph_timespec);
+ *p += sizeof(u32);
+ ceph_decode_32_safe(p, end, namelen, bad);
+ *p += sizeof(namelen);
+ if (infoversion >= 2) {
+ ceph_decode_32_safe(p, end, num_export_targets, bad);
+ pexport_targets = *p;
+ *p += sizeof(num_export_targets * sizeof(u32));
+ } else {
+ num_export_targets = 0;
+ }
+
+ dout("mdsmap_decode %d/%d mds%d.%d %s %s\n",
+ i+1, n, 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].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++)
+ ceph_decode_32(&pexport_targets,
+ m->m_info[mds].export_targets[j]);
+ } 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++)
+ ceph_decode_32(p, m->m_data_pg_pools[i]);
+ ceph_decode_32(p, m->m_cas_pg_pool);
+
+ /* 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");
+ 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);
+}