On Tue, 2017-09-12 at 10:53 +0800, Yan, Zheng wrote:
> utsname() can return NULL while process is exiting. kernel releases
> file locks during process exits. We send request to mds when releasing
> file lock. So it's possible that we open mds session while process is
> exiting. utsname() is called in create_session_open_msg()
>
> Signed-off-by: "Yan, Zheng" <zyan@xxxxxxxxxx>
> ---
> fs/ceph/mds_client.c | 6 ++++--
> fs/ceph/mds_client.h | 3 +++
> 2 files changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
> index 26893cc1fbee..ab6b998d3f44 100644
> --- a/fs/ceph/mds_client.c
> +++ b/fs/ceph/mds_client.c
> @@ -884,8 +884,8 @@ static struct ceph_msg *create_session_open_msg(struct ceph_mds_client *mdsc, u6
> void *p;
>
> const char* metadata[][2] = {
> - {"hostname", utsname()->nodename},
> - {"kernel_version", utsname()->release},
> + {"hostname", mdsc->nodename},
> + {"kernel_version", init_utsname()->release},
> {"entity_id", opt->name ? : ""},
> {"root", fsopt->server_path ? : "/"},
> {NULL, NULL}
> @@ -3558,6 +3558,8 @@ int ceph_mdsc_init(struct ceph_fs_client *fsc)
> init_rwsem(&mdsc->pool_perm_rwsem);
> mdsc->pool_perm_tree = RB_ROOT;
>
> + strncpy(mdsc->nodename, utsname()->nodename,
> + sizeof(mdsc->nodename) - 1);
> return 0;
> }
>
> diff --git a/fs/ceph/mds_client.h b/fs/ceph/mds_client.h
> index db57ae98ed34..636d6b2ec49c 100644
> --- a/fs/ceph/mds_client.h
> +++ b/fs/ceph/mds_client.h
> @@ -8,6 +8,7 @@
> #include <linux/rbtree.h>
> #include <linux/spinlock.h>
> #include <linux/refcount.h>
> +#include <linux/utsname.h>
>
> #include <linux/ceph/types.h>
> #include <linux/ceph/messenger.h>
> @@ -368,6 +369,8 @@ struct ceph_mds_client {
>
> struct rw_semaphore pool_perm_rwsem;
> struct rb_root pool_perm_tree;
> +
> + char nodename[__NEW_UTS_LEN + 1];
> };
>
> extern const char *ceph_mds_op_name(int op);
(nit: might want to add a link to the tracker bug in the description)
Reviewed-by: Jeff Layton <jlayton@xxxxxxxxxx>
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