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path: root/fs/overlayfs/super.c
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Diffstat (limited to 'fs/overlayfs/super.c')
-rw-r--r--fs/overlayfs/super.c398
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");