Signed-off-by: David Howells <[email protected]>
cc: Greg Kroah-Hartman <[email protected]>
cc: "Rafael J. Wysocki" <[email protected]>
---

 fs/debugfs/inode.c |  186 ++++++++++++++++++++++++----------------------------
 1 file changed, 85 insertions(+), 101 deletions(-)

diff --git a/fs/debugfs/inode.c b/fs/debugfs/inode.c
index 95b5e78c22b1..951939bf25ce 100644
--- a/fs/debugfs/inode.c
+++ b/fs/debugfs/inode.c
@@ -12,6 +12,8 @@
 #include <linux/module.h>
 #include <linux/fs.h>
 #include <linux/mount.h>
+#include <linux/fs_context.h>
+#include <linux/fs_parser.h>
 #include <linux/pagemap.h>
 #include <linux/init.h>
 #include <linux/kobject.h>
@@ -20,7 +22,6 @@
 #include <linux/fsnotify.h>
 #include <linux/string.h>
 #include <linux/seq_file.h>
-#include <linux/parser.h>
 #include <linux/magic.h>
 #include <linux/slab.h>
 
@@ -43,73 +44,62 @@ static struct inode *debugfs_get_inode(struct super_block 
*sb)
        return inode;
 }
 
-struct debugfs_mount_opts {
-       kuid_t uid;
-       kgid_t gid;
-       umode_t mode;
-};
-
 enum {
-       Opt_uid,
        Opt_gid,
        Opt_mode,
-       Opt_err
+       Opt_uid,
+};
+
+static const struct fs_parameter_spec debugfs_param_specs[] = {
+       fsparam_u32     ("gid",                         Opt_gid),
+       fsparam_u32oct  ("mode",                        Opt_mode),
+       fsparam_u32     ("uid",                         Opt_uid),
+       {}
 };
 
-static const match_table_t tokens = {
-       {Opt_uid, "uid=%u"},
-       {Opt_gid, "gid=%u"},
-       {Opt_mode, "mode=%o"},
-       {Opt_err, NULL}
+static const struct fs_parameter_description debugfs_fs_parameters = {
+       .name           = "debugfs",
+       .specs          = debugfs_param_specs,
 };
 
 struct debugfs_fs_info {
-       struct debugfs_mount_opts mount_opts;
+       kuid_t uid;
+       kgid_t gid;
+       umode_t mode;
 };
 
-static int debugfs_parse_options(char *data, struct debugfs_mount_opts *opts)
+static int debugfs_parse_param(struct fs_context *fc, struct fs_parameter 
*param)
 {
-       substring_t args[MAX_OPT_ARGS];
-       int option;
-       int token;
+       struct debugfs_fs_info *opts = fc->s_fs_info;
+       struct fs_parse_result result;
        kuid_t uid;
        kgid_t gid;
-       char *p;
-
-       opts->mode = DEBUGFS_DEFAULT_MODE;
-
-       while ((p = strsep(&data, ",")) != NULL) {
-               if (!*p)
-                       continue;
-
-               token = match_token(p, tokens, args);
-               switch (token) {
-               case Opt_uid:
-                       if (match_int(&args[0], &option))
-                               return -EINVAL;
-                       uid = make_kuid(current_user_ns(), option);
-                       if (!uid_valid(uid))
-                               return -EINVAL;
-                       opts->uid = uid;
-                       break;
-               case Opt_gid:
-                       if (match_int(&args[0], &option))
-                               return -EINVAL;
-                       gid = make_kgid(current_user_ns(), option);
-                       if (!gid_valid(gid))
-                               return -EINVAL;
-                       opts->gid = gid;
-                       break;
-               case Opt_mode:
-                       if (match_octal(&args[0], &option))
-                               return -EINVAL;
-                       opts->mode = option & S_IALLUGO;
-                       break;
+       int opt;
+
+       opt = fs_parse(fc, &debugfs_fs_parameters, param, &result);
+       if (opt < 0)
+               return opt;
+
+       switch (opt) {
+       case Opt_uid:
+               uid = make_kuid(current_user_ns(), result.uint_32);
+               if (!uid_valid(uid))
+                       return invalf(fc, "Unknown uid");
+               opts->uid = uid;
+               break;
+       case Opt_gid:
+               gid = make_kgid(current_user_ns(), result.uint_32);
+               if (!gid_valid(gid))
+                       return invalf(fc, "Unknown gid");
+               opts->gid = gid;
+               break;
+       case Opt_mode:
+               opts->mode = result.uint_32 & S_IALLUGO;
+               break;
                /*
                 * We might like to report bad mount options here;
                 * but traditionally debugfs has ignored all mount options
                 */
-               }
        }
 
        return 0;
@@ -119,46 +109,36 @@ static int debugfs_apply_options(struct super_block *sb)
 {
        struct debugfs_fs_info *fsi = sb->s_fs_info;
        struct inode *inode = d_inode(sb->s_root);
-       struct debugfs_mount_opts *opts = &fsi->mount_opts;
 
        inode->i_mode &= ~S_IALLUGO;
-       inode->i_mode |= opts->mode;
+       inode->i_mode |= fsi->mode;
 
-       inode->i_uid = opts->uid;
-       inode->i_gid = opts->gid;
+       inode->i_uid = fsi->uid;
+       inode->i_gid = fsi->gid;
 
        return 0;
 }
 
-static int debugfs_remount(struct super_block *sb, int *flags, char *data)
+static int debugfs_reconfigure(struct fs_context *fc)
 {
-       int err;
-       struct debugfs_fs_info *fsi = sb->s_fs_info;
+       struct super_block *sb = fc->root->d_sb;
 
        sync_filesystem(sb);
-       err = debugfs_parse_options(data, &fsi->mount_opts);
-       if (err)
-               goto fail;
-
-       debugfs_apply_options(sb);
-
-fail:
-       return err;
+       return debugfs_apply_options(sb);
 }
 
 static int debugfs_show_options(struct seq_file *m, struct dentry *root)
 {
        struct debugfs_fs_info *fsi = root->d_sb->s_fs_info;
-       struct debugfs_mount_opts *opts = &fsi->mount_opts;
 
-       if (!uid_eq(opts->uid, GLOBAL_ROOT_UID))
+       if (!uid_eq(fsi->uid, GLOBAL_ROOT_UID))
                seq_printf(m, ",uid=%u",
-                          from_kuid_munged(&init_user_ns, opts->uid));
-       if (!gid_eq(opts->gid, GLOBAL_ROOT_GID))
+                          from_kuid_munged(&init_user_ns, fsi->uid));
+       if (!gid_eq(fsi->gid, GLOBAL_ROOT_GID))
                seq_printf(m, ",gid=%u",
-                          from_kgid_munged(&init_user_ns, opts->gid));
-       if (opts->mode != DEBUGFS_DEFAULT_MODE)
-               seq_printf(m, ",mode=%o", opts->mode);
+                          from_kgid_munged(&init_user_ns, fsi->gid));
+       if (fsi->mode != DEBUGFS_DEFAULT_MODE)
+               seq_printf(m, ",mode=%o", fsi->mode);
 
        return 0;
 }
@@ -173,7 +153,6 @@ static void debugfs_evict_inode(struct inode *inode)
 
 static const struct super_operations debugfs_super_operations = {
        .statfs         = simple_statfs,
-       .remount_fs     = debugfs_remount,
        .show_options   = debugfs_show_options,
        .evict_inode    = debugfs_evict_inode,
 };
@@ -199,51 +178,57 @@ static const struct dentry_operations debugfs_dops = {
        .d_automount = debugfs_automount,
 };
 
-static int debug_fill_super(struct super_block *sb, void *data, int silent)
+static int debugfs_fill_super(struct super_block *sb, struct fs_context *fc)
 {
        static const struct tree_descr debug_files[] = {{""}};
-       struct debugfs_fs_info *fsi;
        int err;
 
-       fsi = kzalloc(sizeof(struct debugfs_fs_info), GFP_KERNEL);
-       sb->s_fs_info = fsi;
-       if (!fsi) {
-               err = -ENOMEM;
-               goto fail;
-       }
-
-       err = debugfs_parse_options(data, &fsi->mount_opts);
+       err = simple_fill_super(sb, DEBUGFS_MAGIC, debug_files);
        if (err)
-               goto fail;
-
-       err  =  simple_fill_super(sb, DEBUGFS_MAGIC, debug_files);
-       if (err)
-               goto fail;
+               return err;
 
        sb->s_op = &debugfs_super_operations;
        sb->s_d_op = &debugfs_dops;
 
-       debugfs_apply_options(sb);
+       return debugfs_apply_options(sb);
+}
 
-       return 0;
+static int debugfs_get_tree(struct fs_context *fc)
+{
+       return vfs_get_super(fc, vfs_get_single_reconf_super,
+                            debugfs_fill_super);
+}
 
-fail:
-       kfree(fsi);
-       sb->s_fs_info = NULL;
-       return err;
+static void debugfs_free_fc(struct fs_context *fc)
+{
+       kfree(fc->s_fs_info);
 }
 
-static struct dentry *debug_mount(struct file_system_type *fs_type,
-                       int flags, const char *dev_name,
-                       void *data)
+static const struct fs_context_operations debugfs_context_ops = {
+       .free           = debugfs_free_fc,
+       .parse_param    = debugfs_parse_param,
+       .get_tree       = debugfs_get_tree,
+       .reconfigure    = debugfs_reconfigure,
+};
+
+static int debugfs_init_fs_context(struct fs_context *fc)
 {
-       return mount_single(fs_type, flags, data, debug_fill_super);
+       struct debugfs_fs_info *fsi;
+
+       fsi = kzalloc(sizeof(struct debugfs_fs_info), GFP_KERNEL);
+       if (!fsi)
+               return -ENOMEM;
+
+       fc->s_fs_info = fsi;
+       fc->ops = &debugfs_context_ops;
+       return 0;
 }
 
 static struct file_system_type debug_fs_type = {
        .owner =        THIS_MODULE,
        .name =         "debugfs",
-       .mount =        debug_mount,
+       .init_fs_context = debugfs_init_fs_context,
+       .parameters     = &debugfs_fs_parameters,
        .kill_sb =      kill_litter_super,
 };
 MODULE_ALIAS_FS("debugfs");
@@ -862,4 +847,3 @@ static int __init debugfs_init(void)
        return retval;
 }
 core_initcall(debugfs_init);
-

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