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Commit a874a63e authored by Liu Bo's avatar Liu Bo Committed by Chris Mason
Browse files

Btrfs: check write access to mount earlier while creating snapshots 



Move check of write access to mount into upper functions so that we can
use mnt_want_write_file instead, which is faster than mnt_want_write.

Signed-off-by: default avatarLiu Bo <liubo2009@cn.fujitsu.com>
parent 287082b0

fs/btrfs/ioctl.c

+11 −11
Original line number Diff line number Diff line
@@ -652,13 +652,9 @@ static noinline int btrfs_mksubvol(struct path *parent, 
	if (dentry->d_inode)

		goto out_dput;



	error = mnt_want_write(parent->mnt);

	if (error)

		goto out_dput;



	error = btrfs_may_create(dir, dentry);

	if (error)

		goto out_drop_write;

		goto out_dput;



	down_read(&BTRFS_I(dir)->root->fs_info->subvol_sem);
@@ -676,8 +672,6 @@ static noinline int btrfs_mksubvol(struct path *parent, 
		fsnotify_mkdir(dir, dentry);

out_up_read:

	up_read(&BTRFS_I(dir)->root->fs_info->subvol_sem);

out_drop_write:

	mnt_drop_write(parent->mnt);

out_dput:

	dput(dentry);

out_unlock:
@@ -1395,16 +1389,20 @@ static noinline int btrfs_ioctl_snap_create_transid(struct file *file, 
	if (root->fs_info->sb->s_flags & MS_RDONLY)

		return -EROFS;



	ret = mnt_want_write_file(file);

	if (ret)

		goto out;



	namelen = strlen(name);

	if (strchr(name, '/')) {

		ret = -EINVAL;

		goto out;

		goto out_drop_write;

	}



	if (name[0] == '.' &&

	   (namelen == 1 || (name[1] == '.' && namelen == 2))) {

		ret = -EEXIST;

		goto out;

		goto out_drop_write;

	}



	if (subvol) {
@@ -1415,7 +1413,7 @@ static noinline int btrfs_ioctl_snap_create_transid(struct file *file, 
		src_file = fget(fd);

		if (!src_file) {

			ret = -EINVAL;

			goto out;

			goto out_drop_write;

		}



		src_inode = src_file->f_path.dentry->d_inode;
@@ -1424,13 +1422,15 @@ static noinline int btrfs_ioctl_snap_create_transid(struct file *file, 
			       "another FS\n");

			ret = -EINVAL;

			fput(src_file);

			goto out;

			goto out_drop_write;

		}

		ret = btrfs_mksubvol(&file->f_path, name, namelen,

				     BTRFS_I(src_inode)->root,

				     transid, readonly);

		fput(src_file);

	}

out_drop_write:

	mnt_drop_write_file(file);

out:

	return ret;

}