On Fri, Jun 4, 2021 at 4:45 PM Jeff Layton <jlayton@xxxxxxxxxx> wrote:
>
> 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.
Ah, ok. I kind of assumed that old user space + new kernel need not be
taken care of.
That means the new kernel should preserve old mount syntax for old
user space helper.
>
> > 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>
>
--
Cheers,
Venky
