diff options
Diffstat (limited to 'fs/overlayfs/params.c')
| -rw-r--r-- | fs/overlayfs/params.c | 78 |
1 files changed, 76 insertions, 2 deletions
diff --git a/fs/overlayfs/params.c b/fs/overlayfs/params.c index 88725982b6dd..ddab9ea267d1 100644 --- a/fs/overlayfs/params.c +++ b/fs/overlayfs/params.c @@ -45,6 +45,8 @@ MODULE_PARM_DESC(metacopy, enum ovl_opt { Opt_lowerdir, + Opt_lowerdir_add, + Opt_datadir_add, Opt_upperdir, Opt_workdir, Opt_default_permissions, @@ -140,8 +142,11 @@ static int ovl_verity_mode_def(void) #define fsparam_string_empty(NAME, OPT) \ __fsparam(fs_param_is_string, NAME, OPT, fs_param_can_be_empty, NULL) + const struct fs_parameter_spec ovl_parameter_spec[] = { fsparam_string_empty("lowerdir", Opt_lowerdir), + fsparam_string("lowerdir+", Opt_lowerdir_add), + fsparam_string("datadir+", Opt_datadir_add), fsparam_string("upperdir", Opt_upperdir), fsparam_string("workdir", Opt_workdir), fsparam_flag("default_permissions", Opt_default_permissions), @@ -273,12 +278,15 @@ static int ovl_mount_dir(const char *name, struct path *path) static int ovl_mount_dir_check(struct fs_context *fc, const struct path *path, enum ovl_opt layer, const char *name, bool upper) { + struct ovl_fs_context *ctx = fc->fs_private; + if (ovl_dentry_weird(path->dentry)) return invalfc(fc, "filesystem on %s not supported", name); if (!d_is_dir(path->dentry)) return invalfc(fc, "%s is not a directory", name); + /* * Check whether upper path is read-only here to report failures * early. Don't forget to recheck when the superblock is created @@ -289,16 +297,45 @@ static int ovl_mount_dir_check(struct fs_context *fc, const struct path *path, return invalfc(fc, "filesystem on %s not supported as upperdir", name); if (__mnt_is_readonly(path->mnt)) return invalfc(fc, "filesystem on %s is read-only", name); + } else { + if (ctx->lowerdir_all && layer != Opt_lowerdir) + return invalfc(fc, "lowerdir+ and datadir+ cannot follow lowerdir"); + if (ctx->nr_data && layer == Opt_lowerdir_add) + return invalfc(fc, "regular lower layers cannot follow data layers"); + if (ctx->nr == OVL_MAX_STACK) + return invalfc(fc, "too many lower directories, limit is %d", + OVL_MAX_STACK); } return 0; } +static int ovl_ctx_realloc_lower(struct fs_context *fc) +{ + struct ovl_fs_context *ctx = fc->fs_private; + struct ovl_fs_context_layer *l; + size_t nr; + + if (ctx->nr < ctx->capacity) + return 0; + + nr = min_t(size_t, max(4096 / sizeof(*l), ctx->capacity * 2), + OVL_MAX_STACK); + l = krealloc_array(ctx->lower, nr, sizeof(*l), GFP_KERNEL_ACCOUNT); + if (!l) + return -ENOMEM; + + ctx->lower = l; + ctx->capacity = nr; + return 0; +} + static void ovl_add_layer(struct fs_context *fc, enum ovl_opt layer, struct path *path, char **pname) { struct ovl_fs *ofs = fc->s_fs_info; struct ovl_config *config = &ofs->config; struct ovl_fs_context *ctx = fc->fs_private; + struct ovl_fs_context_layer *l; switch (layer) { case Opt_workdir: @@ -309,6 +346,16 @@ static void ovl_add_layer(struct fs_context *fc, enum ovl_opt layer, swap(config->upperdir, *pname); swap(ctx->upper, *path); break; + case Opt_datadir_add: + ctx->nr_data++; + fallthrough; + case Opt_lowerdir_add: + WARN_ON(ctx->nr >= ctx->capacity); + l = &ctx->lower[ctx->nr++]; + memset(l, 0, sizeof(*l)); + swap(l->name, *pname); + swap(l->path, *path); + break; default: WARN_ON(1); } @@ -325,7 +372,10 @@ static int ovl_parse_layer(struct fs_context *fc, struct fs_parameter *param, if (!name) return -ENOMEM; - err = ovl_mount_dir(name, &path); + if (upper) + err = ovl_mount_dir(name, &path); + else + err = ovl_mount_dir_noesc(name, &path); if (err) goto out_free; @@ -333,6 +383,12 @@ static int ovl_parse_layer(struct fs_context *fc, struct fs_parameter *param, if (err) goto out_put; + if (!upper) { + err = ovl_ctx_realloc_lower(fc); + if (err) + goto out_put; + } + /* Store the user provided path string in ctx to show in mountinfo */ ovl_add_layer(fc, layer, &path, &name); @@ -519,6 +575,8 @@ static int ovl_parse_param(struct fs_context *fc, struct fs_parameter *param) case Opt_lowerdir: err = ovl_parse_param_lowerdir(param->string, fc); break; + case Opt_lowerdir_add: + case Opt_datadir_add: case Opt_upperdir: case Opt_workdir: err = ovl_parse_layer(fc, param, opt); @@ -894,13 +952,29 @@ int ovl_show_options(struct seq_file *m, struct dentry *dentry) { struct super_block *sb = dentry->d_sb; struct ovl_fs *ofs = OVL_FS(sb); + size_t nr, nr_merged_lower, nr_lower = 0; char **lowerdirs = ofs->config.lowerdirs; /* * lowerdirs[0] holds the colon separated list that user provided * with lowerdir mount option. + * lowerdirs[1..numlayer] hold the lowerdir paths that were added + * using the lowerdir+ and datadir+ mount options. + * For now, we do not allow mixing the legacy lowerdir mount option + * with the new lowerdir+ and datadir+ mount options. */ - seq_show_option(m, "lowerdir", lowerdirs[0]); + if (lowerdirs[0]) { + seq_show_option(m, "lowerdir", lowerdirs[0]); + } else { + nr_lower = ofs->numlayer; + nr_merged_lower = nr_lower - ofs->numdatalayer; + } + for (nr = 1; nr < nr_lower; nr++) { + if (nr < nr_merged_lower) + seq_show_option(m, "lowerdir+", lowerdirs[nr]); + else + seq_show_option(m, "datadir+", lowerdirs[nr]); + } if (ofs->config.upperdir) { seq_show_option(m, "upperdir", ofs->config.upperdir); seq_show_option(m, "workdir", ofs->config.workdir); |