diff options
| -rw-r--r-- | fs/overlayfs/super.c | 398 |
1 files changed, 193 insertions, 205 deletions
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c index dbd9151dc073..cc389701dd6d 100644 --- a/fs/overlayfs/super.c +++ b/fs/overlayfs/super.c @@ -16,6 +16,7 @@ #include <linux/posix_acl_xattr.h> #include <linux/exportfs.h> #include <linux/file.h> +#include <linux/fs_context.h> #include <linux/fs_parser.h> #include "overlayfs.h" @@ -253,7 +254,8 @@ static void ovl_put_super(struct super_block *sb) { struct ovl_fs *ofs = sb->s_fs_info; - ovl_free_fs(ofs); + if (ofs) + ovl_free_fs(ofs); } /* Sync real dirty inodes in upper filesystem (if it exists) */ @@ -408,16 +410,17 @@ static int ovl_show_options(struct seq_file *m, struct dentry *dentry) return 0; } -static int ovl_remount(struct super_block *sb, int *flags, char *data) +static int ovl_reconfigure(struct fs_context *fc) { + struct super_block *sb = fc->root->d_sb; struct ovl_fs *ofs = sb->s_fs_info; struct super_block *upper_sb; int ret = 0; - if (!(*flags & SB_RDONLY) && ovl_force_readonly(ofs)) + if (!(fc->sb_flags & SB_RDONLY) && ovl_force_readonly(ofs)) return -EROFS; - if (*flags & SB_RDONLY && !sb_rdonly(sb)) { + if (fc->sb_flags & SB_RDONLY && !sb_rdonly(sb)) { upper_sb = ovl_upper_mnt(ofs)->mnt_sb; if (ovl_should_sync(ofs)) { down_read(&upper_sb->s_umount); @@ -438,219 +441,151 @@ static const struct super_operations ovl_super_operations = { .sync_fs = ovl_sync_fs, .statfs = ovl_statfs, .show_options = ovl_show_options, - .remount_fs = ovl_remount, }; enum { - OPT_LOWERDIR, - OPT_UPPERDIR, - OPT_WORKDIR, - OPT_DEFAULT_PERMISSIONS, - OPT_REDIRECT_DIR_ON, - OPT_REDIRECT_DIR_OFF, - OPT_REDIRECT_DIR_FOLLOW, - OPT_REDIRECT_DIR_NOFOLLOW, - OPT_INDEX_ON, - OPT_INDEX_OFF, - OPT_UUID_ON, - OPT_UUID_OFF, - OPT_NFS_EXPORT_ON, - OPT_USERXATTR, - OPT_NFS_EXPORT_OFF, - OPT_XINO_ON, - OPT_XINO_OFF, - OPT_XINO_AUTO, - OPT_METACOPY_ON, - OPT_METACOPY_OFF, - OPT_VOLATILE, - OPT_ERR, + Opt_lowerdir, + Opt_upperdir, + Opt_workdir, + Opt_default_permissions, + Opt_redirect_dir, + Opt_index, + Opt_uuid, + Opt_nfs_export, + Opt_userxattr, + Opt_xino, + Opt_metacopy, + Opt_volatile, }; -static const match_table_t ovl_tokens = { - {OPT_LOWERDIR, "lowerdir=%s"}, - {OPT_UPPERDIR, "upperdir=%s"}, - {OPT_WORKDIR, "workdir=%s"}, - {OPT_DEFAULT_PERMISSIONS, "default_permissions"}, - {OPT_REDIRECT_DIR_ON, "redirect_dir=on"}, - {OPT_REDIRECT_DIR_OFF, "redirect_dir=off"}, - {OPT_REDIRECT_DIR_FOLLOW, "redirect_dir=follow"}, - {OPT_REDIRECT_DIR_NOFOLLOW, "redirect_dir=nofollow"}, - {OPT_INDEX_ON, "index=on"}, - {OPT_INDEX_OFF, "index=off"}, - {OPT_USERXATTR, "userxattr"}, - {OPT_UUID_ON, "uuid=on"}, - {OPT_UUID_OFF, "uuid=off"}, - {OPT_NFS_EXPORT_ON, "nfs_export=on"}, - {OPT_NFS_EXPORT_OFF, "nfs_export=off"}, - {OPT_XINO_ON, "xino=on"}, - {OPT_XINO_OFF, "xino=off"}, - {OPT_XINO_AUTO, "xino=auto"}, - {OPT_METACOPY_ON, "metacopy=on"}, - {OPT_METACOPY_OFF, "metacopy=off"}, - {OPT_VOLATILE, "volatile"}, - {OPT_ERR, NULL} +static const struct constant_table ovl_parameter_bool[] = { + { "on", true }, + { "off", false }, + {} }; -static char *ovl_next_opt(char **s) -{ - char *sbegin = *s; - char *p; - - if (sbegin == NULL) - return NULL; +static const struct fs_parameter_spec ovl_parameter_spec[] = { + fsparam_string("lowerdir", Opt_lowerdir), + fsparam_string("upperdir", Opt_upperdir), + fsparam_string("workdir", Opt_workdir), + fsparam_flag("default_permissions", Opt_default_permissions), + fsparam_enum("redirect_dir", Opt_redirect_dir, ovl_parameter_redirect_dir), + fsparam_enum("index", Opt_index, ovl_parameter_bool), + fsparam_enum("uuid", Opt_uuid, ovl_parameter_bool), + fsparam_enum("nfs_export", Opt_nfs_export, ovl_parameter_bool), + fsparam_flag("userxattr", Opt_userxattr), + fsparam_enum("xino", Opt_xino, ovl_parameter_xino), + fsparam_enum("metacopy", Opt_metacopy, ovl_parameter_bool), + fsparam_flag("volatile", Opt_volatile), + {} +}; - for (p = sbegin; *p; p++) { - if (*p == '\\') { - p++; - if (!*p) - break; - } else if (*p == ',') { - *p = '\0'; - *s = p + 1; - return sbegin; - } - } - *s = NULL; - return sbegin; -} +struct ovl_fs_context { + struct ovl_opt_set set; +}; -static int ovl_parse_opt(char *opt, struct ovl_config *config, - struct ovl_opt_set *set) +static int ovl_parse_param(struct fs_context *fc, struct fs_parameter *param) { int err = 0; - int token; - substring_t args[MAX_OPT_ARGS]; + struct fs_parse_result result; + struct ovl_fs *ofs = fc->s_fs_info; + struct ovl_config *config = &ofs->config; + struct ovl_fs_context *ctx = fc->fs_private; + char *dup; + int opt; - if (!*opt) + /* + * On remount overlayfs has always ignored all mount options no + * matter if malformed or not so for backwards compatibility we + * do the same here. + */ + if (fc->purpose == FS_CONTEXT_FOR_RECONFIGURE) return 0; - token = match_token(opt, ovl_tokens, args); - switch (token) { - case OPT_UPPERDIR: - kfree(config->upperdir); - config->upperdir = match_strdup(&args[0]); - if (!config->upperdir) - return -ENOMEM; - break; + opt = fs_parse(fc, ovl_parameter_spec, param, &result); + if (opt < 0) + return opt; - case OPT_LOWERDIR: - kfree(config->lowerdir); - config->lowerdir = match_strdup(&args[0]); - if (!config->lowerdir) - return -ENOMEM; - break; - - case OPT_WORKDIR: - kfree(config->workdir); - config->workdir = match_strdup(&args[0]); - if (!config->workdir) - return -ENOMEM; - break; - - case OPT_DEFAULT_PERMISSIONS: - config->default_permissions = true; - break; - - case OPT_REDIRECT_DIR_ON: - config->redirect_mode = OVL_REDIRECT_ON; - set->redirect = true; - break; - - case OPT_REDIRECT_DIR_OFF: - config->redirect_mode = ovl_redirect_always_follow ? - OVL_REDIRECT_FOLLOW : - OVL_REDIRECT_NOFOLLOW; - set->redirect = true; - break; - - case OPT_REDIRECT_DIR_FOLLOW: - config->redirect_mode = OVL_REDIRECT_FOLLOW; - set->redirect = true; - break; - - case OPT_REDIRECT_DIR_NOFOLLOW: - config->redirect_mode = OVL_REDIRECT_NOFOLLOW; - set->redirect = true; - break; - - case OPT_INDEX_ON: - config->index = true; - set->index = true; - break; + switch (opt) { + case Opt_lowerdir: + dup = kstrdup(param->string, GFP_KERNEL); + if (!dup) { + err = -ENOMEM; + break; + } - case OPT_INDEX_OFF: - config->index = false; - set->index = true; + kfree(config->lowerdir); + config->lowerdir = dup; break; + case Opt_upperdir: + dup = kstrdup(param->string, GFP_KERNEL); + if (!dup) { + err = -ENOMEM; + break; + } - case OPT_UUID_ON: - config->uuid = true; + kfree(config->upperdir); + config->upperdir = dup; break; + case Opt_workdir: + dup = kstrdup(param->string, GFP_KERNEL); + if (!dup) { + err = -ENOMEM; + break; + } - case OPT_UUID_OFF: - config->uuid = false; + kfree(config->workdir); + config->workdir = dup; break; - - case OPT_NFS_EXPORT_ON: - config->nfs_export = true; - set->nfs_export = true; + case Opt_default_permissions: + config->default_permissions = true; break; - - case OPT_NFS_EXPORT_OFF: - config->nfs_export = false; - set->nfs_export = true; + case Opt_redirect_dir: + config->redirect_mode = result.uint_32; + if (config->redirect_mode == OVL_REDIRECT_OFF) { + config->redirect_mode = ovl_redirect_always_follow ? + OVL_REDIRECT_FOLLOW : + OVL_REDIRECT_NOFOLLOW; + } + ctx->set.redirect = true; break; - - case OPT_XINO_ON: - config->xino = OVL_XINO_ON; + case Opt_index: + config->index = result.uint_32; + ctx->set.index = true; break; - - case OPT_XINO_OFF: - config->xino = OVL_XINO_OFF; + case Opt_uuid: + config->uuid = result.uint_32; break; - - case OPT_XINO_AUTO: - config->xino = OVL_XINO_AUTO; + case Opt_nfs_export: + config->nfs_export = result.uint_32; + ctx->set.nfs_export = true; break; - - case OPT_METACOPY_ON: - config->metacopy = true; - set->metacopy = true; + case Opt_xino: + config->xino = result.uint_32; break; - - case OPT_METACOPY_OFF: - config->metacopy = false; - set->metacopy = true; + case Opt_metacopy: + config->metacopy = result.uint_32; + ctx->set.metacopy = true; break; - - case OPT_VOLATILE: + case Opt_volatile: config->ovl_volatile = true; break; - - case OPT_USERXATTR: + case Opt_userxattr: config->userxattr = true; break; - default: pr_err("unrecognized mount option \"%s\" or missing value\n", - opt); + param->key); return -EINVAL; } return err; } -static int ovl_parse_options(char *opt, struct ovl_config *config) +static int ovl_fs_params_verify(const struct ovl_fs_context *ctx, + struct ovl_config *config) { - char *p; - int err; - struct ovl_opt_set set = {}; - - while ((p = ovl_next_opt(&opt)) != NULL) { - err = ovl_parse_opt(p, config, &set); - if (err) - return err; - } + struct ovl_opt_set set = ctx->set; /* Workdir/index are useless in non-upper mount */ if (!config->upperdir) { @@ -1958,12 +1893,13 @@ static struct dentry *ovl_get_root(struct super_block *sb, return root; } -static int ovl_fill_super(struct super_block *sb, void *data, int silent) +static int ovl_fill_super(struct super_block *sb, struct fs_context *fc) { - struct path upperpath = { }; + struct ovl_fs *ofs = sb->s_fs_info; + struct ovl_fs_context *ctx = fc->fs_private; + struct path upperpath = {}; struct dentry *root_dentry; struct ovl_entry *oe; - struct ovl_fs *ofs; struct ovl_layer *layers; struct cred *cred; char *splitlower = NULL; @@ -1971,34 +1907,23 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent) int err; err = -EIO; - if (WARN_ON(sb->s_user_ns != current_user_ns())) - goto out; + if (WARN_ON(fc->user_ns != current_user_ns())) + goto out_err; sb->s_d_op = &ovl_dentry_operations; err = -ENOMEM; - ofs = kzalloc(sizeof(struct ovl_fs), GFP_KERNEL); - if (!ofs) - goto out; - - err = -ENOMEM; ofs->creator_cred = cred = prepare_creds(); if (!cred) goto out_err; - ofs->config.redirect_mode = ovl_redirect_mode_def(); - ofs->config.index = ovl_index_def; - ofs->config.uuid = true; - ofs->config.nfs_export = ovl_nfs_export_def; - ofs->config.xino = ovl_xino_def(); - ofs->config.metacopy = ovl_metacopy_def; - err = ovl_parse_options((char *) data, &ofs->config); + err = ovl_fs_params_verify(ctx, &ofs->config); if (err) goto out_err; err = -EINVAL; if (!ofs->config.lowerdir) { - if (!silent) + if (!(fc->sb_flags & SB_SILENT)) pr_err("missing 'lowerdir'\n"); goto out_err; } @@ -2143,25 +2068,88 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent) out_free_oe: ovl_free_entry(oe); out_err: - kfree(splitlower); - path_put(&upperpath); ovl_free_fs(ofs); -out: + sb->s_fs_info = NULL; return err; } -static struct dentry *ovl_mount(struct file_system_type *fs_type, int flags, - const char *dev_name, void *raw_data) +static int ovl_get_tree(struct fs_context *fc) { - return mount_nodev(fs_type, flags, raw_data, ovl_fill_super); + return get_tree_nodev(fc, ovl_fill_super); +} + +static inline void ovl_fs_context_free(struct ovl_fs_context *ctx) +{ + kfree(ctx); +} + +static void ovl_free(struct fs_context *fc) +{ + struct ovl_fs *ofs = fc->s_fs_info; + struct ovl_fs_context *ctx = fc->fs_private; + + /* + * ofs is stored in the fs_context when it is initialized. + * ofs is transferred to the superblock on a successful mount, + * but if an error occurs before the transfer we have to free + * it here. + */ + if (ofs) + ovl_free_fs(ofs); + + if (ctx) + ovl_fs_context_free(ctx); +} + +static const struct fs_context_operations ovl_context_ops = { + .parse_param = ovl_parse_param, + .get_tree = ovl_get_tree, + .reconfigure = ovl_reconfigure, + .free = ovl_free, +}; + +/* + * This is called during fsopen() and will record the user namespace of + * the caller in fc->user_ns since we've raised FS_USERNS_MOUNT. We'll + * need it when we actually create the superblock to verify that the + * process creating the superblock is in the same user namespace as + * process that called fsopen(). + */ +static int ovl_init_fs_context(struct fs_context *fc) +{ + struct ovl_fs_context *ctx; + struct ovl_fs *ofs; + + ctx = kzalloc(sizeof(*ctx), GFP_KERNEL_ACCOUNT); + if (!ctx) + return -ENOMEM; + + ofs = kzalloc(sizeof(struct ovl_fs), GFP_KERNEL); + if (!ofs) { + ovl_fs_context_free(ctx); + return -ENOMEM; + } + + ofs->config.redirect_mode = ovl_redirect_mode_def(); + ofs->config.index = ovl_index_def; + ofs->config.uuid = true; + ofs->config.nfs_export = ovl_nfs_export_def; + ofs->config.xino = ovl_xino_def(); + ofs->config.metacopy = ovl_metacopy_def; + + fc->s_fs_info = ofs; + fc->fs_private = ctx; + fc->ops = &ovl_context_ops; + return 0; } static struct file_system_type ovl_fs_type = { - .owner = THIS_MODULE, - .name = "overlay", - .fs_flags = FS_USERNS_MOUNT, - .mount = ovl_mount, - .kill_sb = kill_anon_super, + .owner = THIS_MODULE, + .name = "overlay", + .init_fs_context = ovl_init_fs_context, + .parameters = ovl_parameter_spec, + .fs_flags = FS_USERNS_MOUNT, + .kill_sb = kill_anon_super, }; MODULE_ALIAS_FS("overlay"); |