On Fri, 2021-06-04 at 17:12 +0530, Venky Shankar wrote:
> 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.
>
>
Yeah. We have to allow for the entire matrix of old/new kernel with
old/new mount helper.
Note that I don't think we need to worry about displaying the old syntax
in /proc/mounts if someone mounted with it, but we do want kernels to
accept both mount syntaxes, at least for now. Eventually, we should be
able to deprecate the old syntax once we've dropped support pre-Quincy
versions of the mount helper (2-3 years out or so).
> > > 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>
> >
>
>
--
Jeff Layton <jlayton@xxxxxxxxxx>
