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Commit 72fa39f5 authored by Misono, Tomohiro's avatar Misono, Tomohiro Committed by David Sterba
Browse files

btrfs: add btrfs_mount_root() and new file_system_type 



Add btrfs_mount_root() and new file_system_type for preparation of cleanup
of btrfs_mount(). Code path is not changed yet.

btrfs_mount_root() is almost the same as current btrfs_mount(), but doesn't
have subvolume related part.

Signed-off-by: default avatarTomohiro Misono <misono.tomohiro@jp.fujitsu.com>
Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent aab6e9ed

fs/btrfs/super.c

+123 −0
Original line number Diff line number Diff line
@@ -65,7 +65,15 @@ 
#include <trace/events/btrfs.h>



static const struct super_operations btrfs_super_ops;



/*

 * Types for mounting the default subvolume and a subvolume explicitly

 * requested by subvol=/path. That way the callchain is straightforward and we

 * don't have to play tricks with the mount options and recursive calls to

 * btrfs_mount.

 */

static struct file_system_type btrfs_fs_type;

static struct file_system_type btrfs_root_fs_type;



static int btrfs_remount(struct super_block *sb, int *flags, char *data);
@@ -1549,6 +1557,112 @@ static int setup_security_options(struct btrfs_fs_info *fs_info, 
	return ret;

}



static struct dentry *btrfs_mount_root(struct file_system_type *fs_type,

		int flags, const char *device_name, void *data)

{

	struct block_device *bdev = NULL;

	struct super_block *s;

	struct btrfs_fs_devices *fs_devices = NULL;

	struct btrfs_fs_info *fs_info = NULL;

	struct security_mnt_opts new_sec_opts;

	fmode_t mode = FMODE_READ;

	char *subvol_name = NULL;

	u64 subvol_objectid = 0;

	int error = 0;



	if (!(flags & SB_RDONLY))

		mode |= FMODE_WRITE;



	error = btrfs_parse_early_options(data, mode, fs_type,

					  &subvol_name, &subvol_objectid,

					  &fs_devices);

	if (error) {

		kfree(subvol_name);

		return ERR_PTR(error);

	}



	security_init_mnt_opts(&new_sec_opts);

	if (data) {

		error = parse_security_options(data, &new_sec_opts);

		if (error)

			return ERR_PTR(error);

	}



	error = btrfs_scan_one_device(device_name, mode, fs_type, &fs_devices);

	if (error)

		goto error_sec_opts;



	/*

	 * Setup a dummy root and fs_info for test/set super.  This is because

	 * we don't actually fill this stuff out until open_ctree, but we need

	 * it for searching for existing supers, so this lets us do that and

	 * then open_ctree will properly initialize everything later.

	 */

	fs_info = kzalloc(sizeof(struct btrfs_fs_info), GFP_KERNEL);

	if (!fs_info) {

		error = -ENOMEM;

		goto error_sec_opts;

	}



	fs_info->fs_devices = fs_devices;



	fs_info->super_copy = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_KERNEL);

	fs_info->super_for_commit = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_KERNEL);

	security_init_mnt_opts(&fs_info->security_opts);

	if (!fs_info->super_copy || !fs_info->super_for_commit) {

		error = -ENOMEM;

		goto error_fs_info;

	}



	error = btrfs_open_devices(fs_devices, mode, fs_type);

	if (error)

		goto error_fs_info;



	if (!(flags & SB_RDONLY) && fs_devices->rw_devices == 0) {

		error = -EACCES;

		goto error_close_devices;

	}



	bdev = fs_devices->latest_bdev;

	s = sget(fs_type, btrfs_test_super, btrfs_set_super, flags | SB_NOSEC,

		 fs_info);

	if (IS_ERR(s)) {

		error = PTR_ERR(s);

		goto error_close_devices;

	}



	if (s->s_root) {

		btrfs_close_devices(fs_devices);

		free_fs_info(fs_info);

		if ((flags ^ s->s_flags) & SB_RDONLY)

			error = -EBUSY;

	} else {

		snprintf(s->s_id, sizeof(s->s_id), "%pg", bdev);

		btrfs_sb(s)->bdev_holder = fs_type;

		error = btrfs_fill_super(s, fs_devices, data);

	}

	if (error) {

		deactivate_locked_super(s);

		goto error_sec_opts;

	}



	fs_info = btrfs_sb(s);

	error = setup_security_options(fs_info, s, &new_sec_opts);

	if (error) {

		deactivate_locked_super(s);

		goto error_sec_opts;

	}



	return dget(s->s_root);



error_close_devices:

	btrfs_close_devices(fs_devices);

error_fs_info:

	free_fs_info(fs_info);

error_sec_opts:

	security_free_mnt_opts(&new_sec_opts);

	return ERR_PTR(error);

}

/*

 * Find a superblock for the given device / mount point.

 *
@@ -2170,6 +2284,15 @@ static struct file_system_type btrfs_fs_type = { 
	.kill_sb	= btrfs_kill_super,

	.fs_flags	= FS_REQUIRES_DEV | FS_BINARY_MOUNTDATA,

};



static struct file_system_type btrfs_root_fs_type = {

	.owner		= THIS_MODULE,

	.name		= "btrfs",

	.mount		= btrfs_mount_root,

	.kill_sb	= btrfs_kill_super,

	.fs_flags	= FS_REQUIRES_DEV | FS_BINARY_MOUNTDATA,

};



MODULE_ALIAS_FS("btrfs");



static int btrfs_control_open(struct inode *inode, struct file *file)