diff options
Diffstat (limited to 'fs/overlayfs/super.c')
| -rw-r--r-- | fs/overlayfs/super.c | 907 |
1 files changed, 415 insertions, 492 deletions
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c index f97ad8b40dbb..c14c52560fd6 100644 --- a/fs/overlayfs/super.c +++ b/fs/overlayfs/super.c @@ -16,6 +16,8 @@ #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" MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>"); @@ -25,8 +27,6 @@ MODULE_LICENSE("GPL"); struct ovl_dir_cache; -#define OVL_MAX_STACK 500 - static bool ovl_redirect_dir_def = IS_ENABLED(CONFIG_OVERLAY_FS_REDIRECT_DIR); module_param_named(redirect_dir, ovl_redirect_dir_def, bool, 0644); MODULE_PARM_DESC(redirect_dir, @@ -54,29 +54,11 @@ module_param_named(xino_auto, ovl_xino_auto_def, bool, 0644); MODULE_PARM_DESC(xino_auto, "Auto enable xino feature"); -static void ovl_entry_stack_free(struct ovl_entry *oe) -{ - unsigned int i; - - for (i = 0; i < oe->numlower; i++) - dput(oe->lowerstack[i].dentry); -} - static bool ovl_metacopy_def = IS_ENABLED(CONFIG_OVERLAY_FS_METACOPY); module_param_named(metacopy, ovl_metacopy_def, bool, 0644); MODULE_PARM_DESC(metacopy, "Default to on or off for the metadata only copy up feature"); -static void ovl_dentry_release(struct dentry *dentry) -{ - struct ovl_entry *oe = dentry->d_fsdata; - - if (oe) { - ovl_entry_stack_free(oe); - kfree_rcu(oe, rcu); - } -} - static struct dentry *ovl_d_real(struct dentry *dentry, const struct inode *inode) { @@ -99,6 +81,15 @@ static struct dentry *ovl_d_real(struct dentry *dentry, if (real && !inode && ovl_has_upperdata(d_inode(dentry))) return real; + /* + * Best effort lazy lookup of lowerdata for !inode case to return + * the real lowerdata dentry. The only current caller of d_real() with + * NULL inode is d_real_inode() from trace_uprobe and this caller is + * likely going to be followed reading from the file, before placing + * uprobes on offset within the file, so lowerdata should be available + * when setting the uprobe. + */ + ovl_maybe_lookup_lowerdata(dentry); lower = ovl_dentry_lowerdata(dentry); if (!lower) goto bug; @@ -121,6 +112,9 @@ static int ovl_revalidate_real(struct dentry *d, unsigned int flags, bool weak) { int ret = 1; + if (!d) + return 1; + if (weak) { if (d->d_flags & DCACHE_OP_WEAK_REVALIDATE) ret = d->d_op->d_weak_revalidate(d, flags); @@ -138,7 +132,8 @@ static int ovl_revalidate_real(struct dentry *d, unsigned int flags, bool weak) static int ovl_dentry_revalidate_common(struct dentry *dentry, unsigned int flags, bool weak) { - struct ovl_entry *oe = dentry->d_fsdata; + struct ovl_entry *oe = OVL_E(dentry); + struct ovl_path *lowerstack = ovl_lowerstack(oe); struct inode *inode = d_inode_rcu(dentry); struct dentry *upper; unsigned int i; @@ -152,10 +147,9 @@ static int ovl_dentry_revalidate_common(struct dentry *dentry, if (upper) ret = ovl_revalidate_real(upper, flags, weak); - for (i = 0; ret > 0 && i < oe->numlower; i++) { - ret = ovl_revalidate_real(oe->lowerstack[i].dentry, flags, - weak); - } + for (i = 0; ret > 0 && i < ovl_numlower(oe); i++) + ret = ovl_revalidate_real(lowerstack[i].dentry, flags, weak); + return ret; } @@ -170,7 +164,6 @@ static int ovl_dentry_weak_revalidate(struct dentry *dentry, unsigned int flags) } static const struct dentry_operations ovl_dentry_operations = { - .d_release = ovl_dentry_release, .d_real = ovl_d_real, .d_revalidate = ovl_dentry_revalidate, .d_weak_revalidate = ovl_dentry_weak_revalidate, @@ -190,9 +183,8 @@ static struct inode *ovl_alloc_inode(struct super_block *sb) oi->version = 0; oi->flags = 0; oi->__upperdentry = NULL; - oi->lowerpath.dentry = NULL; - oi->lowerpath.layer = NULL; - oi->lowerdata = NULL; + oi->lowerdata_redirect = NULL; + oi->oe = NULL; mutex_init(&oi->lock); return &oi->vfs_inode; @@ -212,11 +204,11 @@ static void ovl_destroy_inode(struct inode *inode) struct ovl_inode *oi = OVL_I(inode); dput(oi->__upperdentry); - dput(oi->lowerpath.dentry); + ovl_free_entry(oi->oe); if (S_ISDIR(inode->i_mode)) ovl_dir_cache_free(inode); else - iput(oi->lowerdata); + kfree(oi->lowerdata_redirect); } static void ovl_free_fs(struct ovl_fs *ofs) @@ -241,6 +233,7 @@ static void ovl_free_fs(struct ovl_fs *ofs) for (i = 0; i < ofs->numlayer; i++) { iput(ofs->layers[i].trap); mounts[i] = ofs->layers[i].mnt; + kfree(ofs->layers[i].name); } kern_unmount_array(mounts, ofs->numlayer); kfree(ofs->layers); @@ -248,10 +241,8 @@ static void ovl_free_fs(struct ovl_fs *ofs) free_anon_bdev(ofs->fs[i].pseudo_dev); kfree(ofs->fs); - kfree(ofs->config.lowerdir); kfree(ofs->config.upperdir); kfree(ofs->config.workdir); - kfree(ofs->config.redirect_mode); if (ofs->creator_cred) put_cred(ofs->creator_cred); kfree(ofs); @@ -261,7 +252,8 @@ 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) */ @@ -337,17 +329,38 @@ static bool ovl_force_readonly(struct ovl_fs *ofs) return (!ovl_upper_mnt(ofs) || !ofs->workdir); } -static const char *ovl_redirect_mode_def(void) +static const struct constant_table ovl_parameter_redirect_dir[] = { + { "off", OVL_REDIRECT_OFF }, + { "follow", OVL_REDIRECT_FOLLOW }, + { "nofollow", OVL_REDIRECT_NOFOLLOW }, + { "on", OVL_REDIRECT_ON }, + {} +}; + +static const char *ovl_redirect_mode(struct ovl_config *config) { - return ovl_redirect_dir_def ? "on" : "off"; + return ovl_parameter_redirect_dir[config->redirect_mode].name; } -static const char * const ovl_xino_str[] = { - "off", - "auto", - "on", +static int ovl_redirect_mode_def(void) +{ + return ovl_redirect_dir_def ? OVL_REDIRECT_ON : + ovl_redirect_always_follow ? OVL_REDIRECT_FOLLOW : + OVL_REDIRECT_NOFOLLOW; +} + +static const struct constant_table ovl_parameter_xino[] = { + { "off", OVL_XINO_OFF }, + { "auto", OVL_XINO_AUTO }, + { "on", OVL_XINO_ON }, + {} }; +static const char *ovl_xino_mode(struct ovl_config *config) +{ + return ovl_parameter_xino[config->xino].name; +} + static inline int ovl_xino_def(void) { return ovl_xino_auto_def ? OVL_XINO_AUTO : OVL_XINO_OFF; @@ -365,16 +378,26 @@ static int ovl_show_options(struct seq_file *m, struct dentry *dentry) { struct super_block *sb = dentry->d_sb; struct ovl_fs *ofs = sb->s_fs_info; - - seq_show_option(m, "lowerdir", ofs->config.lowerdir); + size_t nr, nr_merged_lower = ofs->numlayer - ofs->numdatalayer; + const struct ovl_layer *data_layers = &ofs->layers[nr_merged_lower]; + + /* ofs->layers[0] is the upper layer */ + seq_printf(m, ",lowerdir=%s", ofs->layers[1].name); + /* dump regular lower layers */ + for (nr = 2; nr < nr_merged_lower; nr++) + seq_printf(m, ":%s", ofs->layers[nr].name); + /* dump data lower layers */ + for (nr = 0; nr < ofs->numdatalayer; nr++) + seq_printf(m, "::%s", data_layers[nr].name); if (ofs->config.upperdir) { seq_show_option(m, "upperdir", ofs->config.upperdir); seq_show_option(m, "workdir", ofs->config.workdir); } if (ofs->config.default_permissions) seq_puts(m, ",default_permissions"); - if (strcmp(ofs->config.redirect_mode, ovl_redirect_mode_def()) != 0) - seq_printf(m, ",redirect_dir=%s", ofs->config.redirect_mode); + if (ofs->config.redirect_mode != ovl_redirect_mode_def()) + seq_printf(m, ",redirect_dir=%s", + ovl_redirect_mode(&ofs->config)); if (ofs->config.index != ovl_index_def) seq_printf(m, ",index=%s", ofs->config.index ? "on" : "off"); if (!ofs->config.uuid) @@ -382,8 +405,8 @@ static int ovl_show_options(struct seq_file *m, struct dentry *dentry) if (ofs->config.nfs_export != ovl_nfs_export_def) seq_printf(m, ",nfs_export=%s", ofs->config.nfs_export ? "on" : "off"); - if (ofs->config.xino != ovl_xino_def() && !ovl_same_fs(sb)) - seq_printf(m, ",xino=%s", ovl_xino_str[ofs->config.xino]); + if (ofs->config.xino != ovl_xino_def() && !ovl_same_fs(ofs)) + seq_printf(m, ",xino=%s", ovl_xino_mode(&ofs->config)); if (ofs->config.metacopy != ovl_metacopy_def) seq_printf(m, ",metacopy=%s", ofs->config.metacopy ? "on" : "off"); @@ -394,16 +417,17 @@ 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); @@ -424,215 +448,143 @@ 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, - 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, "redirect_dir=%s"}, - {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; +#define fsparam_string_empty(NAME, OPT) \ + __fsparam(fs_param_is_string, NAME, OPT, fs_param_can_be_empty, NULL) + +static const struct fs_parameter_spec ovl_parameter_spec[] = { + fsparam_string_empty("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), + {} +}; - if (sbegin == NULL) - return NULL; +static int ovl_parse_param(struct fs_context *fc, struct fs_parameter *param) +{ + int err = 0; + 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; + int opt; - 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; -} + if (fc->purpose == FS_CONTEXT_FOR_RECONFIGURE) { + /* + * 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->oldapi) + return 0; -static int ovl_parse_redirect_mode(struct ovl_config *config, const char *mode) -{ - if (strcmp(mode, "on") == 0) { - config->redirect_dir = true; /* - * Does not make sense to have redirect creation without - * redirect following. + * Give us the freedom to allow changing mount options + * with the new mount api in the future. So instead of + * silently ignoring everything we report a proper + * error. This is only visible for users of the new + * mount api. */ - config->redirect_follow = true; - } else if (strcmp(mode, "follow") == 0) { - config->redirect_follow = true; - } else if (strcmp(mode, "off") == 0) { - if (ovl_redirect_always_follow) - config->redirect_follow = true; - } else if (strcmp(mode, "nofollow") != 0) { - pr_err("bad mount option \"redirect_dir=%s\"\n", - mode); + return invalfc(fc, "No changes allowed in reconfigure"); + } + + opt = fs_parse(fc, ovl_parameter_spec, param, &result); + if (opt < 0) + return opt; + + switch (opt) { + case Opt_lowerdir: + err = ovl_parse_param_lowerdir(param->string, fc); + break; + case Opt_upperdir: + fallthrough; + case Opt_workdir: + err = ovl_parse_param_upperdir(param->string, fc, + (Opt_workdir == opt)); + break; + case Opt_default_permissions: + config->default_permissions = true; + break; + 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_index: + config->index = result.uint_32; + ctx->set.index = true; + break; + case Opt_uuid: + config->uuid = result.uint_32; + break; + case Opt_nfs_export: + config->nfs_export = result.uint_32; + ctx->set.nfs_export = true; + break; + case Opt_xino: + config->xino = result.uint_32; + break; + case Opt_metacopy: + config->metacopy = result.uint_32; + ctx->set.metacopy = true; + break; + case Opt_volatile: + config->ovl_volatile = true; + break; + case Opt_userxattr: + config->userxattr = true; + break; + default: + pr_err("unrecognized mount option \"%s\" or missing value\n", + param->key); return -EINVAL; } - return 0; + return err; } -static int ovl_parse_opt(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; - bool metacopy_opt = false, redirect_opt = false; - bool nfs_export_opt = false, index_opt = false; - - config->redirect_mode = kstrdup(ovl_redirect_mode_def(), GFP_KERNEL); - if (!config->redirect_mode) - return -ENOMEM; - - while ((p = ovl_next_opt(&opt)) != NULL) { - int token; - substring_t args[MAX_OPT_ARGS]; - - if (!*p) - continue; - - token = match_token(p, ovl_tokens, args); - switch (token) { - case OPT_UPPERDIR: - kfree(config->upperdir); - config->upperdir = match_strdup(&args[0]); - if (!config->upperdir) - return -ENOMEM; - break; - - 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: - kfree(config->redirect_mode); - config->redirect_mode = match_strdup(&args[0]); - if (!config->redirect_mode) - return -ENOMEM; - redirect_opt = true; - break; - - case OPT_INDEX_ON: - config->index = true; - index_opt = true; - break; - - case OPT_INDEX_OFF: - config->index = false; - index_opt = true; - break; - - case OPT_UUID_ON: - config->uuid = true; - break; - - case OPT_UUID_OFF: - config->uuid = false; - break; - - case OPT_NFS_EXPORT_ON: - config->nfs_export = true; - nfs_export_opt = true; - break; - - case OPT_NFS_EXPORT_OFF: - config->nfs_export = false; - nfs_export_opt = true; - break; - - case OPT_XINO_ON: - config->xino = OVL_XINO_ON; - break; + struct ovl_opt_set set = ctx->set; - case OPT_XINO_OFF: - config->xino = OVL_XINO_OFF; - break; - - case OPT_XINO_AUTO: - config->xino = OVL_XINO_AUTO; - break; - - case OPT_METACOPY_ON: - config->metacopy = true; - metacopy_opt = true; - break; - - case OPT_METACOPY_OFF: - config->metacopy = false; - metacopy_opt = true; - break; - - case OPT_VOLATILE: - config->ovl_volatile = true; - break; - - case OPT_USERXATTR: - config->userxattr = true; - break; - - default: - pr_err("unrecognized mount option \"%s\" or missing value\n", - p); - return -EINVAL; - } + if (ctx->nr_data > 0 && !config->metacopy) { + pr_err("lower data-only dirs require metacopy support.\n"); + return -EINVAL; } /* Workdir/index are useless in non-upper mount */ @@ -643,9 +595,9 @@ static int ovl_parse_opt(char *opt, struct ovl_config *config) kfree(config->workdir); config->workdir = NULL; } - if (config->index && index_opt) { + if (config->index && set.index) { pr_info("option \"index=on\" is useless in a non-upper mount, ignore\n"); - index_opt = false; + set.index = false; } config->index = false; } @@ -655,47 +607,44 @@ static int ovl_parse_opt(char *opt, struct ovl_config *config) config->ovl_volatile = false; } - err = ovl_parse_redirect_mode(config, config->redirect_mode); - if (err) - return err; - /* * This is to make the logic below simpler. It doesn't make any other - * difference, since config->redirect_dir is only used for upper. + * difference, since redirect_dir=on is only used for upper. */ - if (!config->upperdir && config->redirect_follow) - config->redirect_dir = true; + if (!config->upperdir && config->redirect_mode == OVL_REDIRECT_FOLLOW) + config->redirect_mode = OVL_REDIRECT_ON; /* Resolve metacopy -> redirect_dir dependency */ - if (config->metacopy && !config->redirect_dir) { - if (metacopy_opt && redirect_opt) { + if (config->metacopy && config->redirect_mode != OVL_REDIRECT_ON) { + if (set.metacopy && set.redirect) { pr_err("conflicting options: metacopy=on,redirect_dir=%s\n", - config->redirect_mode); + ovl_redirect_mode(config)); return -EINVAL; } - if (redirect_opt) { + if (set.redirect) { /* * There was an explicit redirect_dir=... that resulted * in this conflict. */ pr_info("disabling metacopy due to redirect_dir=%s\n", - config->redirect_mode); + ovl_redirect_mode(config)); config->metacopy = false; } else { /* Automatically enable redirect otherwise. */ - config->redirect_follow = config->redirect_dir = true; + config->redirect_mode = OVL_REDIRECT_ON; } } /* Resolve nfs_export -> index dependency */ if (config->nfs_export && !config->index) { - if (!config->upperdir && config->redirect_follow) { + if (!config->upperdir && + config->redirect_mode != OVL_REDIRECT_NOFOLLOW) { pr_info("NFS export requires \"redirect_dir=nofollow\" on non-upper mount, falling back to nfs_export=off.\n"); config->nfs_export = false; - } else if (nfs_export_opt && index_opt) { + } else if (set.nfs_export && set.index) { pr_err("conflicting options: nfs_export=on,index=off\n"); return -EINVAL; - } else if (index_opt) { + } else if (set.index) { /* * There was an explicit index=off that resulted * in this conflict. @@ -710,11 +659,11 @@ static int ovl_parse_opt(char *opt, struct ovl_config *config) /* Resolve nfs_export -> !metacopy dependency */ if (config->nfs_export && config->metacopy) { - if (nfs_export_opt && metacopy_opt) { + if (set.nfs_export && set.metacopy) { pr_err("conflicting options: nfs_export=on,metacopy=on\n"); return -EINVAL; } - if (metacopy_opt) { + if (set.metacopy) { /* * There was an explicit metacopy=on that resulted * in this conflict. @@ -734,12 +683,13 @@ static int ovl_parse_opt(char *opt, struct ovl_config *config) /* Resolve userxattr -> !redirect && !metacopy dependency */ if (config->userxattr) { - if (config->redirect_follow && redirect_opt) { + if (set.redirect && + config->redirect_mode != OVL_REDIRECT_NOFOLLOW) { pr_err("conflicting options: userxattr,redirect_dir=%s\n", - config->redirect_mode); + ovl_redirect_mode(config)); return -EINVAL; } - if (config->metacopy && metacopy_opt) { + if (config->metacopy && set.metacopy) { pr_err("conflicting options: userxattr,metacopy=on\n"); return -EINVAL; } @@ -749,7 +699,7 @@ static int ovl_parse_opt(char *opt, struct ovl_config *config) * options must be explicitly enabled if used together with * userxattr. */ - config->redirect_dir = config->redirect_follow = false; + config->redirect_mode = OVL_REDIRECT_NOFOLLOW; config->metacopy = false; } @@ -849,69 +799,6 @@ out_err: goto out_unlock; } -static void ovl_unescape(char *s) -{ - char *d = s; - - for (;; s++, d++) { - if (*s == '\\') - s++; - *d = *s; - if (!*s) - break; - } -} - -static int ovl_mount_dir_noesc(const char *name, struct path *path) -{ - int err = -EINVAL; - - if (!*name) { - pr_err("empty lowerdir\n"); - goto out; - } - err = kern_path(name, LOOKUP_FOLLOW, path); - if (err) { - pr_err("failed to resolve '%s': %i\n", name, err); - goto out; - } - err = -EINVAL; - if (ovl_dentry_weird(path->dentry)) { - pr_err("filesystem on '%s' not supported\n", name); - goto out_put; - } - if (!d_is_dir(path->dentry)) { - pr_err("'%s' not a directory\n", name); - goto out_put; - } - return 0; - -out_put: - path_put_init(path); -out: - return err; -} - -static int ovl_mount_dir(const char *name, struct path *path) -{ - int err = -ENOMEM; - char *tmp = kstrdup(name, GFP_KERNEL); - - if (tmp) { - ovl_unescape(tmp); - err = ovl_mount_dir_noesc(tmp, path); - - if (!err && path->dentry->d_flags & DCACHE_OP_REAL) { - pr_err("filesystem on '%s' not supported as upperdir\n", - tmp); - path_put_init(path); - err = -EINVAL; - } - kfree(tmp); - } - return err; -} - static int ovl_check_namelen(const struct path *path, struct ovl_fs *ofs, const char *name) { @@ -932,10 +819,6 @@ static int ovl_lower_dir(const char *name, struct path *path, int fh_type; int err; - err = ovl_mount_dir_noesc(name, path); - if (err) - return err; - err = ovl_check_namelen(path, ofs, name); if (err) return err; @@ -984,26 +867,6 @@ static bool ovl_workdir_ok(struct dentry *workdir, struct dentry *upperdir) return ok; } -static unsigned int ovl_split_lowerdirs(char *str) -{ - unsigned int ctr = 1; - char *s, *d; - - for (s = d = str;; s++, d++) { - if (*s == '\\') { - s++; - } else if (*s == ':') { - *d = '\0'; - ctr++; - continue; - } - *d = *s; - if (!*s) - break; - } - return ctr; -} - static int ovl_own_xattr_get(const struct xattr_handler *handler, struct dentry *dentry, struct inode *inode, const char *name, void *buffer, size_t size) @@ -1104,15 +967,12 @@ static int ovl_report_in_use(struct ovl_fs *ofs, const char *name) } static int ovl_get_upper(struct super_block *sb, struct ovl_fs *ofs, - struct ovl_layer *upper_layer, struct path *upperpath) + struct ovl_layer *upper_layer, + const struct path *upperpath) { struct vfsmount *upper_mnt; int err; - err = ovl_mount_dir(ofs->config.upperdir, upperpath); - if (err) - goto out; - /* Upperdir path should not be r/o */ if (__mnt_is_readonly(upperpath->mnt)) { pr_err("upper fs is r/o, try multi-lower layers mount\n"); @@ -1142,6 +1002,11 @@ static int ovl_get_upper(struct super_block *sb, struct ovl_fs *ofs, upper_layer->idx = 0; upper_layer->fsid = 0; + err = -ENOMEM; + upper_layer->name = kstrdup(ofs->config.upperdir, GFP_KERNEL); + if (!upper_layer->name) + goto out; + /* * Inherit SB_NOSEC flag from upperdir. * @@ -1333,10 +1198,17 @@ static int ovl_make_workdir(struct super_block *sb, struct ovl_fs *ofs, if (err) { pr_warn("failed to set xattr on upper\n"); ofs->noxattr = true; - if (ofs->config.index || ofs->config.metacopy) { - ofs->config.index = false; + if (ovl_redirect_follow(ofs)) { + ofs->config.redirect_mode = OVL_REDIRECT_NOFOLLOW; + pr_warn("...falling back to redirect_dir=nofollow.\n"); + } + if (ofs->config.metacopy) { ofs->config.metacopy = false; - pr_warn("...falling back to index=off,metacopy=off.\n"); + pr_warn("...falling back to metacopy=off.\n"); + } + if (ofs->config.index) { + ofs->config.index = false; + pr_warn("...falling back to index=off.\n"); } /* * xattr support is required for persistent st_ino. @@ -1399,46 +1271,37 @@ out: } static int ovl_get_workdir(struct super_block *sb, struct ovl_fs *ofs, - const struct path *upperpath) + const struct path *upperpath, + const struct path *workpath) { int err; - struct path workpath = { }; - - err = ovl_mount_dir(ofs->config.workdir, &workpath); - if (err) - goto out; err = -EINVAL; - if (upperpath->mnt != workpath.mnt) { + if (upperpath->mnt != workpath->mnt) { pr_err("workdir and upperdir must reside under the same mount\n"); - goto out; + return err; } - if (!ovl_workdir_ok(workpath.dentry, upperpath->dentry)) { + if (!ovl_workdir_ok(workpath->dentry, upperpath->dentry)) { pr_err("workdir and upperdir must be separate subtrees\n"); - goto out; + return err; } - ofs->workbasedir = dget(workpath.dentry); + ofs->workbasedir = dget(workpath->dentry); if (ovl_inuse_trylock(ofs->workbasedir)) { ofs->workdir_locked = true; } else { err = ovl_report_in_use(ofs, "workdir"); if (err) - goto out; + return err; } err = ovl_setup_trap(sb, ofs->workbasedir, &ofs->workbasedir_trap, "workdir"); if (err) - goto out; - - err = ovl_make_workdir(sb, ofs, &workpath); - -out: - path_put(&workpath); + return err; - return err; + return ovl_make_workdir(sb, ofs, workpath); } static int ovl_get_indexdir(struct super_block *sb, struct ovl_fs *ofs, @@ -1454,7 +1317,7 @@ static int ovl_get_indexdir(struct super_block *sb, struct ovl_fs *ofs, /* Verify lower root is upper root origin */ err = ovl_verify_origin(ofs, upperpath->dentry, - oe->lowerstack[0].dentry, true); + ovl_lowerstack(oe)->dentry, true); if (err) { pr_err("failed to verify upper root origin\n"); goto out; @@ -1574,7 +1437,7 @@ static int ovl_get_fsid(struct ovl_fs *ofs, const struct path *path) pr_warn("%s uuid detected in lower fs '%pd2', falling back to xino=%s,index=off,nfs_export=off.\n", uuid_is_null(&sb->s_uuid) ? "null" : "conflicting", - path->dentry, ovl_xino_str[ofs->config.xino]); + path->dentry, ovl_xino_mode(&ofs->config)); } } @@ -1591,19 +1454,31 @@ static int ovl_get_fsid(struct ovl_fs *ofs, const struct path *path) return ofs->numfs++; } +/* + * The fsid after the last lower fsid is used for the data layers. + * It is a "null fs" with a null sb, null uuid, and no pseudo dev. + */ +static int ovl_get_data_fsid(struct ovl_fs *ofs) +{ + return ofs->numfs; +} + + static int ovl_get_layers(struct super_block *sb, struct ovl_fs *ofs, - struct path *stack, unsigned int numlower, - struct ovl_layer *layers) + struct ovl_fs_context *ctx, struct ovl_layer *layers) { int err; unsigned int i; + size_t nr_merged_lower; - err = -ENOMEM; - ofs->fs = kcalloc(numlower + 1, sizeof(struct ovl_sb), GFP_KERNEL); + ofs->fs = kcalloc(ctx->nr + 2, sizeof(struct ovl_sb), GFP_KERNEL); if (ofs->fs == NULL) - goto out; + return -ENOMEM; - /* idx/fsid 0 are reserved for upper fs even with lower only overlay */ + /* + * idx/fsid 0 are reserved for upper fs even with lower only overlay + * and the last fsid is reserved for "null fs" of the data layers. + */ ofs->numfs++; /* @@ -1615,7 +1490,7 @@ static int ovl_get_layers(struct super_block *sb, struct ovl_fs *ofs, err = get_anon_bdev(&ofs->fs[0].pseudo_dev); if (err) { pr_err("failed to get anonymous bdev for upper fs\n"); - goto out; + return err; } if (ovl_upper_mnt(ofs)) { @@ -1623,14 +1498,19 @@ static int ovl_get_layers(struct super_block *sb, struct ovl_fs *ofs, ofs->fs[0].is_lower = false; } - for (i = 0; i < numlower; i++) { + nr_merged_lower = ctx->nr - ctx->nr_data; + for (i = 0; i < ctx->nr; i++) { + struct ovl_fs_context_layer *l = &ctx->lower[i]; struct vfsmount *mnt; struct inode *trap; int fsid; - err = fsid = ovl_get_fsid(ofs, &stack[i]); - if (err < 0) - goto out; + if (i < nr_merged_lower) + fsid = ovl_get_fsid(ofs, &l->path); + else + fsid = ovl_get_data_fsid(ofs); + if (fsid < 0) + return fsid; /* * Check if lower root conflicts with this overlay layers before @@ -1639,24 +1519,24 @@ static int ovl_get_layers(struct super_block *sb, struct ovl_fs *ofs, * the upperdir/workdir is in fact in-use by our * upperdir/workdir. */ - err = ovl_setup_trap(sb, stack[i].dentry, &trap, "lowerdir"); + err = ovl_setup_trap(sb, l->path.dentry, &trap, "lowerdir"); if (err) - goto out; + return err; - if (ovl_is_inuse(stack[i].dentry)) { + if (ovl_is_inuse(l->path.dentry)) { err = ovl_report_in_use(ofs, "lowerdir"); if (err) { iput(trap); - goto out; + return err; } } - mnt = clone_private_mount(&stack[i]); + mnt = clone_private_mount(&l->path); err = PTR_ERR(mnt); if (IS_ERR(mnt)) { pr_err("failed to clone lowerpath\n"); iput(trap); - goto out; + return err; } /* @@ -1670,6 +1550,8 @@ static int ovl_get_layers(struct super_block *sb, struct ovl_fs *ofs, layers[ofs->numlayer].idx = ofs->numlayer; layers[ofs->numlayer].fsid = fsid; layers[ofs->numlayer].fs = &ofs->fs[fsid]; + layers[ofs->numlayer].name = l->name; + l->name = NULL; ofs->numlayer++; ofs->fs[fsid].is_lower = true; } @@ -1706,69 +1588,63 @@ static int ovl_get_layers(struct super_block *sb, struct ovl_fs *ofs, ofs->xino_mode); } - err = 0; -out: - return err; + return 0; } static struct ovl_entry *ovl_get_lowerstack(struct super_block *sb, - const char *lower, unsigned int numlower, - struct ovl_fs *ofs, struct ovl_layer *layers) + struct ovl_fs_context *ctx, + struct ovl_fs *ofs, + struct ovl_layer *layers) { int err; - struct path *stack = NULL; unsigned int i; + size_t nr_merged_lower; struct ovl_entry *oe; + struct ovl_path *lowerstack; - if (!ofs->config.upperdir && numlower == 1) { + struct ovl_fs_context_layer *l; + + if (!ofs->config.upperdir && ctx->nr == 1) { pr_err("at least 2 lowerdir are needed while upperdir nonexistent\n"); return ERR_PTR(-EINVAL); } - stack = kcalloc(numlower, sizeof(struct path), GFP_KERNEL); - if (!stack) - return ERR_PTR(-ENOMEM); - err = -EINVAL; - for (i = 0; i < numlower; i++) { - err = ovl_lower_dir(lower, &stack[i], ofs, &sb->s_stack_depth); - if (err) - goto out_err; + for (i = 0; i < ctx->nr; i++) { + l = &ctx->lower[i]; - lower = strchr(lower, '\0') + 1; + err = ovl_lower_dir(l->name, &l->path, ofs, &sb->s_stack_depth); + if (err) + return ERR_PTR(err); } err = -EINVAL; sb->s_stack_depth++; if (sb->s_stack_depth > FILESYSTEM_MAX_STACK_DEPTH) { pr_err("maximum fs stacking depth exceeded\n"); - goto out_err; + return ERR_PTR(err); } - err = ovl_get_layers(sb, ofs, stack, numlower, layers); + err = ovl_get_layers(sb, ofs, ctx, layers); if (err) - goto out_err; + return ERR_PTR(err); err = -ENOMEM; - oe = ovl_alloc_entry(numlower); + /* Data-only layers are not merged in root directory */ + nr_merged_lower = ctx->nr - ctx->nr_data; + oe = ovl_alloc_entry(nr_merged_lower); if (!oe) - goto out_err; + return ERR_PTR(err); - for (i = 0; i < numlower; i++) { - oe->lowerstack[i].dentry = dget(stack[i].dentry); - oe->lowerstack[i].layer = &ofs->layers[i+1]; + lowerstack = ovl_lowerstack(oe); + for (i = 0; i < nr_merged_lower; i++) { + l = &ctx->lower[i]; + lowerstack[i].dentry = dget(l->path.dentry); + lowerstack[i].layer = &ofs->layers[i + 1]; } - -out: - for (i = 0; i < numlower; i++) - path_put(&stack[i]); - kfree(stack); + ofs->numdatalayer = ctx->nr_data; return oe; - -out_err: - oe = ERR_PTR(err); - goto out; } /* @@ -1849,20 +1725,18 @@ static struct dentry *ovl_get_root(struct super_block *sb, struct ovl_entry *oe) { struct dentry *root; - struct ovl_path *lowerpath = &oe->lowerstack[0]; + struct ovl_path *lowerpath = ovl_lowerstack(oe); unsigned long ino = d_inode(lowerpath->dentry)->i_ino; int fsid = lowerpath->layer->fsid; struct ovl_inode_params oip = { .upperdentry = upperdentry, - .lowerpath = lowerpath, + .oe = oe, }; root = d_make_root(ovl_new_inode(sb, S_IFDIR, 0)); if (!root) return NULL; - root->d_fsdata = oe; - if (upperdentry) { /* Root inode uses upper st_ino/i_ino */ ino = d_inode(upperdentry)->i_ino; @@ -1877,73 +1751,47 @@ static struct dentry *ovl_get_root(struct super_block *sb, ovl_dentry_set_flag(OVL_E_CONNECTED, root); ovl_set_upperdata(d_inode(root)); ovl_inode_init(d_inode(root), &oip, ino, fsid); - ovl_dentry_update_reval(root, upperdentry, DCACHE_OP_WEAK_REVALIDATE); + ovl_dentry_init_flags(root, upperdentry, oe, DCACHE_OP_WEAK_REVALIDATE); + /* root keeps a reference of upperdentry */ + dget(upperdentry); 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 dentry *root_dentry; struct ovl_entry *oe; - struct ovl_fs *ofs; struct ovl_layer *layers; struct cred *cred; - char *splitlower = NULL; - unsigned int numlower; 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; - /* Is there a reason anyone would want not to share whiteouts? */ - ofs->share_whiteout = true; - - 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_opt((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 (ctx->nr == 0) { + if (!(fc->sb_flags & SB_SILENT)) pr_err("missing 'lowerdir'\n"); goto out_err; } err = -ENOMEM; - splitlower = kstrdup(ofs->config.lowerdir, GFP_KERNEL); - if (!splitlower) - goto out_err; - - err = -EINVAL; - numlower = ovl_split_lowerdirs(splitlower); - if (numlower > OVL_MAX_STACK) { - pr_err("too many lower directories, limit is %d\n", - OVL_MAX_STACK); - goto out_err; - } - - err = -ENOMEM; - layers = kcalloc(numlower + 1, sizeof(struct ovl_layer), GFP_KERNEL); + layers = kcalloc(ctx->nr + 1, sizeof(struct ovl_layer), GFP_KERNEL); if (!layers) goto out_err; @@ -1975,7 +1823,7 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent) goto out_err; } - err = ovl_get_upper(sb, ofs, &layers[0], &upperpath); + err = ovl_get_upper(sb, ofs, &layers[0], &ctx->upper); if (err) goto out_err; @@ -1989,7 +1837,7 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent) } } - err = ovl_get_workdir(sb, ofs, &upperpath); + err = ovl_get_workdir(sb, ofs, &ctx->upper, &ctx->work); if (err) goto out_err; @@ -1999,7 +1847,7 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent) sb->s_stack_depth = upper_sb->s_stack_depth; sb->s_time_gran = upper_sb->s_time_gran; } - oe = ovl_get_lowerstack(sb, splitlower, numlower, ofs, layers); + oe = ovl_get_lowerstack(sb, ctx, ofs, layers); err = PTR_ERR(oe); if (IS_ERR(oe)) goto out_err; @@ -2014,7 +1862,7 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent) } if (!ovl_force_readonly(ofs) && ofs->config.index) { - err = ovl_get_indexdir(sb, ofs, oe, &upperpath); + err = ovl_get_indexdir(sb, ofs, oe, &ctx->upper); if (err) goto out_free_oe; @@ -2055,40 +1903,115 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent) sb->s_iflags |= SB_I_SKIP_SYNC; err = -ENOMEM; - root_dentry = ovl_get_root(sb, upperpath.dentry, oe); + root_dentry = ovl_get_root(sb, ctx->upper.dentry, oe); if (!root_dentry) goto out_free_oe; - mntput(upperpath.mnt); - kfree(splitlower); - sb->s_root = root_dentry; return 0; out_free_oe: - ovl_entry_stack_free(oe); - kfree(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) +{ + ovl_parse_param_drop_lowerdir(ctx); + path_put(&ctx->upper); + path_put(&ctx->work); + kfree(ctx->lower); + 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; + + /* + * By default we allocate for three lower layers. It's likely + * that it'll cover most users. + */ + ctx->lower = kmalloc_array(3, sizeof(*ctx->lower), GFP_KERNEL_ACCOUNT); + if (!ctx->lower) + goto out_err; + ctx->capacity = 3; + + ofs = kzalloc(sizeof(struct ovl_fs), GFP_KERNEL); + if (!ofs) + 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; + + fc->s_fs_info = ofs; + fc->fs_private = ctx; + fc->ops = &ovl_context_ops; + return 0; + +out_err: + ovl_fs_context_free(ctx); + return -ENOMEM; + } 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"); |