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Commit 8246a781 authored by Daniel Rosenberg's avatar Daniel Rosenberg
Browse files

ANDROID: 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: default avatarDaniel Rosenberg <drosen@google.com>
parent b6045659

fs/sdcardfs/main.c

+91 −12
Original line number Diff line number Diff line
@@ -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 @@ static int sdcardfs_read_super(struct super_block *sb, const char *dev_name, 
}



/* 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);
@@ -328,17 +393,29 @@ 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,

	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) {

	struct sdcardfs_sb_info *sbi;

	if (sb->s_magic == SDCARDFS_SUPER_MAGIC) {
@@ -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,

};

fs/sdcardfs/sdcardfs.h

+8 −0
Original line number Diff line number Diff line
@@ -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;

fs/sdcardfs/super.c

+58 −6
Original line number Diff line number Diff line
@@ -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,