[ As I said, I didn't fully reviewed this patch. Just sending out a few
comments. ]
On Mon, Jun 28, 2021 at 01:25:42PM +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@fsid.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 | 117 +++++++++++++++++++++++++++++++++++++++++++-----
> fs/ceph/super.h | 3 ++
> 2 files changed, 110 insertions(+), 10 deletions(-)
>
> diff --git a/fs/ceph/super.c b/fs/ceph/super.c
> index 9b1b7f4cfdd4..950a28ad9c59 100644
> --- a/fs/ceph/super.c
> +++ b/fs/ceph/super.c
> @@ -145,6 +145,7 @@ enum {
> Opt_mds_namespace,
> Opt_recover_session,
> Opt_source,
> + Opt_mon_addr,
> /* string args above */
> Opt_dirstat,
> Opt_rbytes,
> @@ -196,6 +197,7 @@ 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),
> {}
> @@ -226,10 +228,68 @@ static void canonicalize_path(char *path)
> path[j] = '\0';
> }
>
> +static int ceph_parse_old_source(const char *dev_name, const char *dev_name_end,
> + struct fs_context *fc)
> +{
> + int r;
> + struct ceph_parse_opts_ctx *pctx = fc->fs_private;
> + struct ceph_mount_options *fsopt = pctx->opts;
> +
> + if (*dev_name_end != ':')
> + return invalfc(fc, "separator ':' missing in source");
> +
> + r = ceph_parse_mon_ips(dev_name, dev_name_end - dev_name,
> + pctx->copts, fc->log.log);
> + if (r)
> + return r;
> +
> + fsopt->new_dev_syntax = false;
> + return 0;
> +}
> +
> +static int ceph_parse_new_source(const char *dev_name, const char *dev_name_end,
> + struct fs_context *fc)
> +{
> + struct ceph_parse_opts_ctx *pctx = fc->fs_private;
> + struct ceph_mount_options *fsopt = pctx->opts;
> + char *fsid_start, *fs_name_start;
> +
> + if (*dev_name_end != '=')
> + return invalfc(fc, "separator '=' missing in source");
An annoying thing is that we'll always see this error message when falling
back to the old_source method.
(Also, is there a good reason for using '=' instead of ':'? I probably
missed this discussion somewhere else already...)
> +
> + fsid_start = strchr(dev_name, '@');
> + if (!fsid_start)
> + return invalfc(fc, "missing cluster fsid");
> + ++fsid_start; /* start of cluster fsid */
> +
> + fs_name_start = strchr(fsid_start, '.');
> + if (!fs_name_start)
> + return invalfc(fc, "missing file system name");
> +
> + ++fs_name_start; /* start of file system name */
> + fsopt->mds_namespace = kstrndup(fs_name_start,
> + dev_name_end - fs_name_start, GFP_KERNEL);
> + if (!fsopt->mds_namespace)
> + return -ENOMEM;
> + dout("file system (mds namespace) '%s'\n", fsopt->mds_namespace);
> +
> + fsopt->new_dev_syntax = true;
> + return 0;
> +}
> +
> /*
> - * Parse the source parameter. Distinguish the server list from the path.
> + * Parse the source parameter for new device format. Distinguish the device
> + * spec from the path. Try parsing new device format and fallback to old
> + * format if needed.
> *
> - * The source will look like:
> + * New device syntax will looks like:
> + * <device_spec>=/<path>
> + * where
> + * <device_spec> is name@fsid.fsname
> + * <path> is optional, but if present must begin with '/'
> + * (monitor addresses are passed via mount option)
> + *
> + * Old device syntax is:
> * <server_spec>[,<server_spec>...]:[<path>]
> * where
> * <server_spec> is <ip>[:<port>]
> @@ -262,22 +322,48 @@ 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)
> + return invalfc(fc, "path missing 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);
> + dout("trying new device syntax");
> + ret = ceph_parse_new_source(dev_name, dev_name_end, fc);
> + if (ret == 0)
> + goto done;
> +
> + dout("trying old device syntax");
> + ret = ceph_parse_old_source(dev_name, dev_name_end, fc);
> if (ret)
> - return ret;
> + goto out;
>
> + done:
> fc->source = param->string;
> param->string = NULL;
> - return 0;
> + out:
> + return ret;
> +}
> +
> +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;
I think this will result in a memory leak. Why don't we simply set
fsopt->mon_addr to param->string instead of kstrdup'ing it?
Cheers,
--
Luís
> + return r;
> }
>
> static int ceph_parse_mount_param(struct fs_context *fc,
> @@ -322,6 +408,8 @@ 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 +561,7 @@ 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 +605,10 @@ 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);
> }
>
> @@ -571,9 +664,13 @@ 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)
> + /* dump mds_namespace when old device syntax is in use */
> + if (fsopt->mds_namespace && !fsopt->new_dev_syntax)
> 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 839e6b0239ee..557348ff3203 100644
> --- a/fs/ceph/super.h
> +++ b/fs/ceph/super.h
> @@ -88,6 +88,8 @@ struct ceph_mount_options {
> unsigned int max_readdir; /* max readdir result (entries) */
> unsigned int max_readdir_bytes; /* max readdir result (bytes) */
>
> + bool new_dev_syntax;
> +
> /*
> * everything above this point can be memcmp'd; everything below
> * is handled in compare_mount_options()
> @@ -97,6 +99,7 @@ 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 {
> --
> 2.27.0
>
