On Fri, 2021-06-04 at 10:35 +0530, Venky Shankar wrote:
> Old mount device syntax (source) has the following problems:
>
> - mounts to the same cluster but with different fsnames
> and/or creds have identical device string which can
> confuse xfstests.
>
> - Userspace mount helper tool resolves monitor addresses
> and fill in mon addrs automatically, but that means the
> device shown in /proc/mounts is different than what was
> used for mounting.
>
> New device syntax is as follows:
>
> cephuser@mycephfs2=/path
>
> Note, there is no "monitor address" in the device string.
> That gets passed in as mount option. This keeps the device
> string same when monitor addresses change (on remounts).
>
> Also note that the userspace mount helper tool is backward
> compatible. I.e., the mount helper will fallback to using
> old syntax after trying to mount with the new syntax.
>
> Signed-off-by: Venky Shankar <vshankar@xxxxxxxxxx>
> ---
> fs/ceph/super.c | 69 +++++++++++++++++++++++++++++++++----------------
> fs/ceph/super.h | 1 +
> 2 files changed, 48 insertions(+), 22 deletions(-)
>
> diff --git a/fs/ceph/super.c b/fs/ceph/super.c
> index 9b1b7f4cfdd4..e273eabb0397 100644
> --- a/fs/ceph/super.c
> +++ b/fs/ceph/super.c
> @@ -142,9 +142,9 @@ enum {
> Opt_congestion_kb,
> /* int args above */
> Opt_snapdirname,
> - Opt_mds_namespace,
I don't think we can just remove the old mds_namespace option. What if
we have an old mount helper with the new kernel? It'll pass that in as
an option and it wouldn't be recognized.
> Opt_recover_session,
> Opt_source,
> + Opt_mon_addr,
> /* string args above */
> Opt_dirstat,
> Opt_rbytes,
> @@ -184,7 +184,6 @@ static const struct fs_parameter_spec ceph_mount_parameters[] = {
> fsparam_flag_no ("fsc", Opt_fscache), // fsc|nofsc
> fsparam_string ("fsc", Opt_fscache), // fsc=...
> fsparam_flag_no ("ino32", Opt_ino32),
> - fsparam_string ("mds_namespace", Opt_mds_namespace),
> fsparam_flag_no ("poolperm", Opt_poolperm),
> fsparam_flag_no ("quotadf", Opt_quotadf),
> fsparam_u32 ("rasize", Opt_rasize),
> @@ -196,6 +195,7 @@ static const struct fs_parameter_spec ceph_mount_parameters[] = {
> fsparam_u32 ("rsize", Opt_rsize),
> fsparam_string ("snapdirname", Opt_snapdirname),
> fsparam_string ("source", Opt_source),
> + fsparam_string ("mon_addr", Opt_mon_addr),
> fsparam_u32 ("wsize", Opt_wsize),
> fsparam_flag_no ("wsync", Opt_wsync),
> {}
> @@ -227,12 +227,12 @@ static void canonicalize_path(char *path)
> }
>
> /*
> - * Parse the source parameter. Distinguish the server list from the path.
> + * Parse the source parameter. Distinguish the device spec from the path.
> *
> * The source will look like:
> - * <server_spec>[,<server_spec>...]:[<path>]
> + * <device_spec>=/<path>
> * where
> - * <server_spec> is <ip>[:<port>]
> + * <device_spec> is name@fsname
> * <path> is optional, but if present must begin with '/'
> */
> static int ceph_parse_source(struct fs_parameter *param, struct fs_context *fc)
> @@ -240,12 +240,17 @@ static int ceph_parse_source(struct fs_parameter *param, struct fs_context *fc)
> struct ceph_parse_opts_ctx *pctx = fc->fs_private;
> struct ceph_mount_options *fsopt = pctx->opts;
> char *dev_name = param->string, *dev_name_end;
> - int ret;
> + char *fs_name_start;
>
> dout("%s '%s'\n", __func__, dev_name);
> if (!dev_name || !*dev_name)
> return invalfc(fc, "Empty source");
>
> + fs_name_start = strchr(dev_name, '@');
> + if (!fs_name_start)
> + return invalfc(fc, "Missing file system name");
> + ++fs_name_start; /* start of file system name */
> +
> dev_name_end = strchr(dev_name, '/');
> if (dev_name_end) {
> /*
> @@ -262,24 +267,42 @@ static int ceph_parse_source(struct fs_parameter *param, struct fs_context *fc)
> dev_name_end = dev_name + strlen(dev_name);
> }
>
> - dev_name_end--; /* back up to ':' separator */
> - if (dev_name_end < dev_name || *dev_name_end != ':')
> - return invalfc(fc, "No path or : separator in source");
> + dev_name_end--; /* back up to '=' separator */
> + if (dev_name_end < dev_name || *dev_name_end != '=')
> + return invalfc(fc, "No path or = separator in source");
>
> dout("device name '%.*s'\n", (int)(dev_name_end - dev_name), dev_name);
> - if (fsopt->server_path)
> - dout("server path '%s'\n", fsopt->server_path);
>
> - ret = ceph_parse_mon_ips(param->string, dev_name_end - dev_name,
> - pctx->copts, fc->log.log);
> - if (ret)
> - return ret;
> + fsopt->mds_namespace = kstrndup(fs_name_start,
> + dev_name_end - fs_name_start, GFP_KERNEL);
> + dout("file system (mds namespace) '%s'\n", fsopt->mds_namespace);
>
> + if (fsopt->server_path)
> + dout("server path '%s'\n", fsopt->server_path);
> fc->source = param->string;
> param->string = NULL;
> return 0;
> }
>
> +static int ceph_parse_mon_addr(struct fs_parameter *param,
> + struct fs_context *fc)
> +{
> + int r;
> + struct ceph_parse_opts_ctx *pctx = fc->fs_private;
> + struct ceph_mount_options *fsopt = pctx->opts;
> +
> + kfree(fsopt->mon_addr);
> + fsopt->mon_addr = kstrdup(param->string, GFP_KERNEL);
> + if (!fsopt->mon_addr)
> + return -ENOMEM;
> +
> + strreplace(param->string, '/', ',');
> + r = ceph_parse_mon_ips(param->string, strlen(param->string),
> + pctx->copts, fc->log.log);
> + param->string = NULL;
> + return r;
> +}
> +
> static int ceph_parse_mount_param(struct fs_context *fc,
> struct fs_parameter *param)
> {
> @@ -304,11 +327,6 @@ static int ceph_parse_mount_param(struct fs_context *fc,
> fsopt->snapdir_name = param->string;
> param->string = NULL;
> break;
> - case Opt_mds_namespace:
> - kfree(fsopt->mds_namespace);
> - fsopt->mds_namespace = param->string;
> - param->string = NULL;
> - break;
> case Opt_recover_session:
> mode = result.uint_32;
> if (mode == ceph_recover_session_no)
> @@ -322,6 +340,8 @@ static int ceph_parse_mount_param(struct fs_context *fc,
> if (fc->source)
> return invalfc(fc, "Multiple sources specified");
> return ceph_parse_source(param, fc);
> + case Opt_mon_addr:
> + return ceph_parse_mon_addr(param, fc);
> case Opt_wsize:
> if (result.uint_32 < PAGE_SIZE ||
> result.uint_32 > CEPH_MAX_WRITE_SIZE)
> @@ -473,6 +493,7 @@ static void destroy_mount_options(struct ceph_mount_options *args)
> kfree(args->mds_namespace);
> kfree(args->server_path);
> kfree(args->fscache_uniq);
> + kfree(args->mon_addr);
> kfree(args);
> }
>
> @@ -516,6 +537,10 @@ static int compare_mount_options(struct ceph_mount_options *new_fsopt,
> if (ret)
> return ret;
>
> + ret = strcmp_null(fsopt1->mon_addr, fsopt2->mon_addr);
> + if (ret)
> + return ret;
> +
> return ceph_compare_options(new_opt, fsc->client);
> }
>
> @@ -571,8 +596,8 @@ static int ceph_show_options(struct seq_file *m, struct dentry *root)
> if ((fsopt->flags & CEPH_MOUNT_OPT_NOCOPYFROM) == 0)
> seq_puts(m, ",copyfrom");
>
> - if (fsopt->mds_namespace)
> - seq_show_option(m, "mds_namespace", fsopt->mds_namespace);
> + if (fsopt->mon_addr)
> + seq_printf(m, ",mon_addr=%s", fsopt->mon_addr);
>
> if (fsopt->flags & CEPH_MOUNT_OPT_CLEANRECOVER)
> seq_show_option(m, "recover_session", "clean");
> diff --git a/fs/ceph/super.h b/fs/ceph/super.h
> index db80d89556b1..ead73dfb8804 100644
> --- a/fs/ceph/super.h
> +++ b/fs/ceph/super.h
> @@ -97,6 +97,7 @@ struct ceph_mount_options {
> char *mds_namespace; /* default NULL */
> char *server_path; /* default NULL (means "/") */
> char *fscache_uniq; /* default NULL */
> + char *mon_addr;
> };
>
> struct ceph_fs_client {
--
Jeff Layton <jlayton@xxxxxxxxxx>
