Well, after double-checking the code, it seems the wait process will be
unconditionally waked up if new MDS map received. Is there a situation
that the client is pushed a new MDS map, but still no mds active. If so,
maybe worth a little bit optimization such as calling check_new_map() to
avoid the client be uselessly waked up ...
On 2013/12/9 22:26, Li Wang wrote:
Personally, I don't think there is issue for current implementation,
either. If no ACTIVE mds, the mount process put to wait, until updated
MDS map received and with active mds present indicated in the map, it
will be waked up and go on the mount process, otherwise, EIO returned if
timeout. If it is boring to hang for a long time, you can specify a
shorter mount timeout.
On 2013/12/8 2:59, Mikhail Campos Guadamuz wrote:
For http://tracker.ceph.com/issues/4386
It determines situation, when a user is trying to mount CephFS
with no MDS present. Return ECOMM from
open_root_dentry which can be analyzed then by ceph.mount
Signed-off-by: Mikhail Campos Guadamuz <plageat90@xxxxxxxxx>
---
fs/ceph/mdsmap.c | 19 ++++++++++++++++---
fs/ceph/super.c | 10 +++++++++-
include/linux/ceph/mdsmap.h | 1 +
3 files changed, 26 insertions(+), 4 deletions(-)
diff --git a/fs/ceph/mdsmap.c b/fs/ceph/mdsmap.c
index 132b64e..3a6ba8a 100644
--- a/fs/ceph/mdsmap.c
+++ b/fs/ceph/mdsmap.c
@@ -12,6 +12,20 @@
#include "super.h"
+/*
+ * count active mds's
+ */
+int ceph_mdsmap_active_mds_count(struct ceph_mdsmap *m)
+{
+ int n = 0;
+ int i;
+
+ for(i = 0; i < m->m_max_mds; ++i)
+ if(m->m_info[i].state > 0)
+ ++n;
+
+ return n;
+}
/*
* choose a random mds that is "up" (i.e. has a state > 0), or -1.
@@ -26,9 +40,8 @@ int ceph_mdsmap_get_random_mds(struct ceph_mdsmap *m)
return 0;
/* count */
- for (i = 0; i < m->m_max_mds; i++)
- if (m->m_info[i].state > 0)
- n++;
+ n = ceph_mdsmap_active_mds_count(m);
+
if (n == 0)
return -1;
diff --git a/fs/ceph/super.c b/fs/ceph/super.c
index 6627b26..4d33d68 100644
--- a/fs/ceph/super.c
+++ b/fs/ceph/super.c
@@ -674,7 +674,15 @@ static struct dentry *open_root_dentry(struct
ceph_fs_client *fsc,
struct ceph_mds_request *req = NULL;
int err;
struct dentry *root;
-
+
+ /* check for mds*/
+ if( 0 == ceph_mdsmap_active_mds_count(mdsc->mdsmap) )
+ {
+ pr_info("active mds not found, possible not exist\n");
+ root = ERR_PTR( -ECOMM );
+ return root;
+ }
+
/* open dir */
dout("open_root_inode opening '%s'\n", path);
req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_GETATTR,
USE_ANY_MDS);
diff --git a/include/linux/ceph/mdsmap.h b/include/linux/ceph/mdsmap.h
index 87ed09f..4d7d502 100644
--- a/include/linux/ceph/mdsmap.h
+++ b/include/linux/ceph/mdsmap.h
@@ -56,6 +56,7 @@ static inline bool ceph_mdsmap_is_laggy(struct
ceph_mdsmap *m, int w)
return false;
}
+extern int ceph_mdsmap_active_mds_count(struct ceph_mdsmap *m);
extern int ceph_mdsmap_get_random_mds(struct ceph_mdsmap *m);
extern struct ceph_mdsmap *ceph_mdsmap_decode(void **p, void *end);
extern void ceph_mdsmap_destroy(struct ceph_mdsmap *m);
--
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