sdcardfs: Add gid and mask to private mount data

Adds support for mount2, remount2, and the functions
to allocate/clone/copy the private data

The next patch will switch over to actually using it.

Change-Id: I8a43da26021d33401f655f0b2784ead161c575e3
Signed-off-by: Daniel Rosenberg <drosen@google.com>

diff --git a/fs/sdcardfs/main.c b/fs/sdcardfs/main.c
index 3666aef3e0f0e14b2be0166f27897bbbcb35c94f..a693a35928adc8630b185328c6cef06374194783 100644 (file)
--- a/fs/sdcardfs/main.c
+++ b/fs/sdcardfs/main.c
@@ -49,7 +49,8 @@ static const match_table_t sdcardfs_tokens = {
 };
 
 static int parse_options(struct super_block *sb, char *options, int silent,
-                               int *debug, struct sdcardfs_mount_options *opts)
+                               int *debug, struct sdcardfs_vfsmount_options *vfsopts,
+                               struct sdcardfs_mount_options *opts)
 {
        char *p;
        substring_t args[MAX_OPT_ARGS];
@@ -58,9 +59,11 @@ static int parse_options(struct super_block *sb, char *options, int silent,
        /* by default, we use AID_MEDIA_RW as uid, gid */
        opts->fs_low_uid = AID_MEDIA_RW;
        opts->fs_low_gid = AID_MEDIA_RW;
+       vfsopts->mask = 0;
        opts->mask = 0;
        opts->multiuser = false;
        opts->fs_user_id = 0;
+       vfsopts->gid = 0;
        opts->gid = 0;
        /* by default, 0MB is reserved */
        opts->reserved_mb = 0;
@@ -95,6 +98,7 @@ static int parse_options(struct super_block *sb, char *options, int silent,
                        if (match_int(&args[0], &option))
                                return 0;
                        opts->gid = option;
+                       vfsopts->gid = option;
                        break;
                case Opt_userid:
                        if (match_int(&args[0], &option))
@@ -105,6 +109,7 @@ static int parse_options(struct super_block *sb, char *options, int silent,
                        if (match_int(&args[0], &option))
                                return 0;
                        opts->mask = option;
+                       vfsopts->mask = option;
                        break;
                case Opt_multiuser:
                        opts->multiuser = true;
@@ -135,6 +140,65 @@ static int parse_options(struct super_block *sb, char *options, int silent,
        return 0;
 }
 
+int parse_options_remount(struct super_block *sb, char *options, int silent,
+                               struct sdcardfs_vfsmount_options *vfsopts)
+{
+       char *p;
+       substring_t args[MAX_OPT_ARGS];
+       int option;
+       int debug;
+
+       if (!options)
+               return 0;
+
+       while ((p = strsep(&options, ",")) != NULL) {
+               int token;
+               if (!*p)
+                       continue;
+
+               token = match_token(p, sdcardfs_tokens, args);
+
+               switch (token) {
+               case Opt_debug:
+                       debug = 1;
+                       break;
+               case Opt_gid:
+                       if (match_int(&args[0], &option))
+                               return 0;
+                       vfsopts->gid = option;
+
+                       break;
+               case Opt_mask:
+                       if (match_int(&args[0], &option))
+                               return 0;
+                       vfsopts->mask = option;
+                       break;
+               case Opt_multiuser:
+               case Opt_userid:
+               case Opt_fsuid:
+               case Opt_fsgid:
+               case Opt_reserved_mb:
+                       printk( KERN_WARNING "Option \"%s\" can't be changed during remount\n", p);
+                       break;
+               /* unknown option */
+               default:
+                       if (!silent) {
+                               printk( KERN_ERR "Unrecognized mount option \"%s\" "
+                                               "or missing value", p);
+                       }
+                       return -EINVAL;
+               }
+       }
+
+       if (debug) {
+               printk( KERN_INFO "sdcardfs : options - debug:%d\n", debug);
+               printk( KERN_INFO "sdcardfs : options - gid:%d\n", vfsopts->gid);
+               printk( KERN_INFO "sdcardfs : options - mask:%d\n", vfsopts->mask);
+       }
+
+       return 0;
+}
+
 #if 0
 /*
  * our custom d_alloc_root work-alike
@@ -172,14 +236,15 @@ EXPORT_SYMBOL_GPL(sdcardfs_super_list);
  * There is no need to lock the sdcardfs_super_info's rwsem as there is no
  * way anyone can have a reference to the superblock at this point in time.
  */
-static int sdcardfs_read_super(struct super_block *sb, const char *dev_name,
-                                               void *raw_data, int silent)
+static int sdcardfs_read_super(struct vfsmount *mnt, struct super_block *sb,
+               const char *dev_name, void *raw_data, int silent)
 {
        int err = 0;
        int debug;
        struct super_block *lower_sb;
        struct path lower_path;
        struct sdcardfs_sb_info *sb_info;
+       struct sdcardfs_vfsmount_options *mnt_opt = mnt->data;
        struct inode *inode;
 
        printk(KERN_INFO "sdcardfs version 2.0\n");
@@ -212,7 +277,7 @@ static int sdcardfs_read_super(struct super_block *sb, const char *dev_name,
 
        sb_info = sb->s_fs_info;
        /* parse options */
-       err = parse_options(sb, raw_data, silent, &debug, &sb_info->options);
+       err = parse_options(sb, raw_data, silent, &debug, mnt_opt, &sb_info->options);
        if (err) {
                printk(KERN_ERR "sdcardfs: invalid options\n");
                goto out_freesbi;
@@ -306,9 +371,9 @@ out:
 }
 
 /* A feature which supports mount_nodev() with options */
-static struct dentry *mount_nodev_with_options(struct file_system_type *fs_type,
-        int flags, const char *dev_name, void *data,
-        int (*fill_super)(struct super_block *, const char *, void *, int))
+static struct dentry *mount_nodev_with_options(struct vfsmount *mnt,
+       struct file_system_type *fs_type, int flags, const char *dev_name, void *data,
+        int (*fill_super)(struct vfsmount *, struct super_block *, const char *, void *, int))
 
 {
        int error;
@@ -319,7 +384,7 @@ static struct dentry *mount_nodev_with_options(struct file_system_type *fs_type,
 
        s->s_flags = flags;
 
-       error = fill_super(s, dev_name, data, flags & MS_SILENT ? 1 : 0);
+       error = fill_super(mnt, s, dev_name, data, flags & MS_SILENT ? 1 : 0);
        if (error) {
                deactivate_locked_super(s);
                return ERR_PTR(error);
@@ -328,15 +393,27 @@ static struct dentry *mount_nodev_with_options(struct file_system_type *fs_type,
        return dget(s->s_root);
 }
 
-struct dentry *sdcardfs_mount(struct file_system_type *fs_type, int flags,
+static struct dentry *sdcardfs_mount(struct vfsmount *mnt,
+               struct file_system_type *fs_type, int flags,
                            const char *dev_name, void *raw_data)
 {
        /*
         * dev_name is a lower_path_name,
         * raw_data is a option string.
         */
-       return mount_nodev_with_options(fs_type, flags, dev_name,
-                                       raw_data, sdcardfs_read_super);
+       return mount_nodev_with_options(mnt, fs_type, flags, dev_name,
+                                               raw_data, sdcardfs_read_super);
+}
+
+static struct dentry *sdcardfs_mount_wrn(struct file_system_type *fs_type, int flags,
+                   const char *dev_name, void *raw_data)
+{
+       WARN(1, "sdcardfs does not support mount. Use mount2.\n");
+       return ERR_PTR(-EINVAL);
+}
+
+void *sdcardfs_alloc_mnt_data(void) {
+       return kmalloc(sizeof(struct sdcardfs_vfsmount_options), GFP_KERNEL);
 }
 
 void sdcardfs_kill_sb(struct super_block *sb) {
@@ -353,7 +430,9 @@ void sdcardfs_kill_sb(struct super_block *sb) {
 static struct file_system_type sdcardfs_fs_type = {
        .owner          = THIS_MODULE,
        .name           = SDCARDFS_NAME,
-       .mount          = sdcardfs_mount,
+       .mount          = sdcardfs_mount_wrn,
+       .mount2         = sdcardfs_mount,
+       .alloc_mnt_data = sdcardfs_alloc_mnt_data,
        .kill_sb        = sdcardfs_kill_sb,
        .fs_flags       = 0,
 };

diff --git a/fs/sdcardfs/sdcardfs.h b/fs/sdcardfs/sdcardfs.h
index 1931d5bd6cdd9dce1505b5573edb2be16d936f6a..8ed143a16fcce148085808da7e74c8a18f8eaaa7 100644 (file)
--- a/fs/sdcardfs/sdcardfs.h
+++ b/fs/sdcardfs/sdcardfs.h
@@ -193,6 +193,14 @@ struct sdcardfs_mount_options {
        unsigned int reserved_mb;
 };
 
+struct sdcardfs_vfsmount_options {
+       gid_t gid;
+       mode_t mask;
+};
+
+extern int parse_options_remount(struct super_block *sb, char *options, int silent,
+               struct sdcardfs_vfsmount_options *vfsopts);
+
 /* sdcardfs super-block data in memory */
 struct sdcardfs_sb_info {
        struct super_block *sb;

diff --git a/fs/sdcardfs/super.c b/fs/sdcardfs/super.c
index 0a465395aab7f7f83fb4d4a4230d624df1448f85..edda32b68dc08d5f48213f0c20d75aac4b3fd07b 100644 (file)
--- a/fs/sdcardfs/super.c
+++ b/fs/sdcardfs/super.c
@@ -108,6 +108,50 @@ static int sdcardfs_remount_fs(struct super_block *sb, int *flags, char *options
        return err;
 }
 
+/*
+ * @mnt: mount point we are remounting
+ * @sb: superblock we are remounting
+ * @flags: numeric mount options
+ * @options: mount options string
+ */
+static int sdcardfs_remount_fs2(struct vfsmount *mnt, struct super_block *sb,
+                                               int *flags, char *options)
+{
+       int err = 0;
+
+       /*
+        * The VFS will take care of "ro" and "rw" flags among others.  We
+        * can safely accept a few flags (RDONLY, MANDLOCK), and honor
+        * SILENT, but anything else left over is an error.
+        */
+       if ((*flags & ~(MS_RDONLY | MS_MANDLOCK | MS_SILENT | MS_REMOUNT)) != 0) {
+               printk(KERN_ERR
+                      "sdcardfs: remount flags 0x%x unsupported\n", *flags);
+               err = -EINVAL;
+       }
+       printk(KERN_INFO "Remount options were %s for vfsmnt %p.\n", options, mnt);
+       err = parse_options_remount(sb, options, *flags & ~MS_SILENT, mnt->data);
+
+
+       return err;
+}
+
+static void* sdcardfs_clone_mnt_data(void *data) {
+       struct sdcardfs_vfsmount_options* opt = kmalloc(sizeof(struct sdcardfs_vfsmount_options), GFP_KERNEL);
+       struct sdcardfs_vfsmount_options* old = data;
+       if(!opt) return NULL;
+       opt->gid = old->gid;
+       opt->mask = old->mask;
+       return opt;
+}
+
+static void sdcardfs_copy_mnt_data(void *data, void *newdata) {
+       struct sdcardfs_vfsmount_options* old = data;
+       struct sdcardfs_vfsmount_options* new = newdata;
+       old->gid = new->gid;
+       old->mask = new->mask;
+}
+
 /*
  * Called by iput() when the inode reference count reached zero
  * and the inode is not hashed anywhere.  Used to clear anything
@@ -191,19 +235,24 @@ static void sdcardfs_umount_begin(struct super_block *sb)
                lower_sb->s_op->umount_begin(lower_sb);
 }
 
-static int sdcardfs_show_options(struct seq_file *m, struct dentry *root)
+static int sdcardfs_show_options(struct vfsmount *mnt, struct seq_file *m, struct dentry *root)
 {
        struct sdcardfs_sb_info *sbi = SDCARDFS_SB(root->d_sb);
        struct sdcardfs_mount_options *opts = &sbi->options;
+       struct sdcardfs_vfsmount_options *vfsopts = mnt->data;
 
        if (opts->fs_low_uid != 0)
-               seq_printf(m, ",uid=%u", opts->fs_low_uid);
+               seq_printf(m, ",fsuid=%u", opts->fs_low_uid);
        if (opts->fs_low_gid != 0)
-               seq_printf(m, ",gid=%u", opts->fs_low_gid);
-
+               seq_printf(m, ",fsgid=%u", opts->fs_low_gid);
+       if (vfsopts->gid != 0)
+               seq_printf(m, ",gid=%u", vfsopts->gid);
        if (opts->multiuser)
                seq_printf(m, ",multiuser");
-
+       if (vfsopts->mask)
+               seq_printf(m, ",mask=%u", vfsopts->mask);
+       if (opts->fs_user_id)
+               seq_printf(m, ",userid=%u", opts->fs_user_id);
        if (opts->reserved_mb != 0)
                seq_printf(m, ",reserved=%uMB", opts->reserved_mb);
 
@@ -214,9 +263,12 @@ const struct super_operations sdcardfs_sops = {
        .put_super      = sdcardfs_put_super,
        .statfs         = sdcardfs_statfs,
        .remount_fs     = sdcardfs_remount_fs,
+       .remount_fs2    = sdcardfs_remount_fs2,
+       .clone_mnt_data = sdcardfs_clone_mnt_data,
+       .copy_mnt_data  = sdcardfs_copy_mnt_data,
        .evict_inode    = sdcardfs_evict_inode,
        .umount_begin   = sdcardfs_umount_begin,
-       .show_options   = sdcardfs_show_options,
+       .show_options2  = sdcardfs_show_options,
        .alloc_inode    = sdcardfs_alloc_inode,
        .destroy_inode  = sdcardfs_destroy_inode,
        .drop_inode     = generic_delete_inode,