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Commit 5ac00add authored by Stefan Behrens's avatar Stefan Behrens Committed by Josef Bacik
Browse files

Btrfs: disallow mutually exclusive admin operations from user mode 



Btrfs admin operations that are manually started from user mode
and that cannot be executed at the same time return -EINPROGRESS.
A common way to enter and leave this locked section is introduced
since it used to be specific to the balance operation.

Signed-off-by: default avatarStefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: default avatarChris Mason <chris.mason@fusionio.com>
parent a2bff640

fs/btrfs/ctree.h

+2 −0
Original line number Diff line number Diff line
@@ -1527,6 +1527,8 @@ struct btrfs_fs_info { 


	/* device replace state */

	struct btrfs_dev_replace dev_replace;



	atomic_t mutually_exclusive_operation_running;

};



/*

fs/btrfs/ioctl.c

+36 −17
Original line number Diff line number Diff line
@@ -1317,13 +1317,13 @@ static noinline int btrfs_ioctl_resize(struct btrfs_root *root, 
	if (!capable(CAP_SYS_ADMIN))

		return -EPERM;



	mutex_lock(&root->fs_info->volume_mutex);

	if (root->fs_info->balance_ctl) {

		printk(KERN_INFO "btrfs: balance in progress\n");

		ret = -EINVAL;

		goto out;

	if (atomic_xchg(&root->fs_info->mutually_exclusive_operation_running,

			1)) {

		pr_info("btrfs: dev add/delete/balance/replace/resize operation in progress\n");

		return -EINPROGRESS;

	}



	mutex_lock(&root->fs_info->volume_mutex);

	vol_args = memdup_user(arg, sizeof(*vol_args));

	if (IS_ERR(vol_args)) {

		ret = PTR_ERR(vol_args);
@@ -1419,6 +1419,7 @@ static noinline int btrfs_ioctl_resize(struct btrfs_root *root, 
	kfree(vol_args);

out:

	mutex_unlock(&root->fs_info->volume_mutex);

	atomic_set(&root->fs_info->mutually_exclusive_operation_running, 0);

	return ret;

}
@@ -2160,9 +2161,17 @@ static int btrfs_ioctl_defrag(struct file *file, void __user *argp) 
	if (btrfs_root_readonly(root))

		return -EROFS;



	if (atomic_xchg(&root->fs_info->mutually_exclusive_operation_running,

			1)) {

		pr_info("btrfs: dev add/delete/balance/replace/resize operation in progress\n");

		return -EINPROGRESS;

	}

	ret = mnt_want_write_file(file);

	if (ret)

	if (ret) {

		atomic_set(&root->fs_info->mutually_exclusive_operation_running,

			   0);

		return ret;

	}



	switch (inode->i_mode & S_IFMT) {

	case S_IFDIR:
@@ -2214,6 +2223,7 @@ static int btrfs_ioctl_defrag(struct file *file, void __user *argp) 
	}

out:

	mnt_drop_write_file(file);

	atomic_set(&root->fs_info->mutually_exclusive_operation_running, 0);

	return ret;

}
@@ -2225,13 +2235,13 @@ static long btrfs_ioctl_add_dev(struct btrfs_root *root, void __user *arg) 
	if (!capable(CAP_SYS_ADMIN))

		return -EPERM;



	mutex_lock(&root->fs_info->volume_mutex);

	if (root->fs_info->balance_ctl) {

		printk(KERN_INFO "btrfs: balance in progress\n");

		ret = -EINVAL;

		goto out;

	if (atomic_xchg(&root->fs_info->mutually_exclusive_operation_running,

			1)) {

		pr_info("btrfs: dev add/delete/balance/replace/resize operation in progress\n");

		return -EINPROGRESS;

	}



	mutex_lock(&root->fs_info->volume_mutex);

	vol_args = memdup_user(arg, sizeof(*vol_args));

	if (IS_ERR(vol_args)) {

		ret = PTR_ERR(vol_args);
@@ -2244,6 +2254,7 @@ static long btrfs_ioctl_add_dev(struct btrfs_root *root, void __user *arg) 
	kfree(vol_args);

out:

	mutex_unlock(&root->fs_info->volume_mutex);

	atomic_set(&root->fs_info->mutually_exclusive_operation_running, 0);

	return ret;

}
@@ -2258,13 +2269,13 @@ static long btrfs_ioctl_rm_dev(struct btrfs_root *root, void __user *arg) 
	if (root->fs_info->sb->s_flags & MS_RDONLY)

		return -EROFS;



	mutex_lock(&root->fs_info->volume_mutex);

	if (root->fs_info->balance_ctl) {

		printk(KERN_INFO "btrfs: balance in progress\n");

		ret = -EINVAL;

		goto out;

	if (atomic_xchg(&root->fs_info->mutually_exclusive_operation_running,

			1)) {

		pr_info("btrfs: dev add/delete/balance/replace/resize operation in progress\n");

		return -EINPROGRESS;

	}



	mutex_lock(&root->fs_info->volume_mutex);

	vol_args = memdup_user(arg, sizeof(*vol_args));

	if (IS_ERR(vol_args)) {

		ret = PTR_ERR(vol_args);
@@ -2277,6 +2288,7 @@ static long btrfs_ioctl_rm_dev(struct btrfs_root *root, void __user *arg) 
	kfree(vol_args);

out:

	mutex_unlock(&root->fs_info->volume_mutex);

	atomic_set(&root->fs_info->mutually_exclusive_operation_running, 0);

	return ret;

}
@@ -3319,6 +3331,7 @@ static long btrfs_ioctl_balance(struct file *file, void __user *arg) 
	struct btrfs_ioctl_balance_args *bargs;

	struct btrfs_balance_control *bctl;

	int ret;

	int need_to_clear_lock = 0;



	if (!capable(CAP_SYS_ADMIN))

		return -EPERM;
@@ -3354,10 +3367,13 @@ static long btrfs_ioctl_balance(struct file *file, void __user *arg) 
		bargs = NULL;

	}



	if (fs_info->balance_ctl) {

	if (atomic_xchg(&root->fs_info->mutually_exclusive_operation_running,

			1)) {

		pr_info("btrfs: dev add/delete/balance/replace/resize operation in progress\n");

		ret = -EINPROGRESS;

		goto out_bargs;

	}

	need_to_clear_lock = 1;



	bctl = kzalloc(sizeof(*bctl), GFP_NOFS);

	if (!bctl) {
@@ -3391,6 +3407,9 @@ static long btrfs_ioctl_balance(struct file *file, void __user *arg) 
out_bargs:

	kfree(bargs);

out:

	if (need_to_clear_lock)

		atomic_set(&root->fs_info->mutually_exclusive_operation_running,

			   0);

	mutex_unlock(&fs_info->balance_mutex);

	mutex_unlock(&fs_info->volume_mutex);

	mnt_drop_write_file(file);

fs/btrfs/volumes.c

+2 −0
Original line number Diff line number Diff line
@@ -2952,6 +2952,7 @@ static int balance_kthread(void *data) 
		ret = btrfs_balance(fs_info->balance_ctl, NULL);

	}



	atomic_set(&fs_info->mutually_exclusive_operation_running, 0);

	mutex_unlock(&fs_info->balance_mutex);

	mutex_unlock(&fs_info->volume_mutex);
@@ -2974,6 +2975,7 @@ int btrfs_resume_balance_async(struct btrfs_fs_info *fs_info) 
		return 0;

	}



	WARN_ON(atomic_xchg(&fs_info->mutually_exclusive_operation_running, 1));

	tsk = kthread_run(balance_kthread, fs_info, "btrfs-balance");

	if (IS_ERR(tsk))

		return PTR_ERR(tsk);