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Commit 1406e432 authored by Josef Bacik's avatar Josef Bacik Committed by Chris Mason
Browse files

Btrfs: add a "df" ioctl for btrfs 



df is a very loaded question in btrfs.  This gives us a way to get the per-space
usage information so we can tell exactly what is in use where.  This will help
us figure out ENOSPC problems, and help users better understand where their disk
space is going.

Signed-off-by: default avatarJosef Bacik <josef@redhat.com>
Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
parent 2ac55d41

fs/btrfs/ioctl.c

+45 −0
Original line number Diff line number Diff line
@@ -1843,6 +1843,49 @@ static long btrfs_ioctl_default_subvol(struct file *file, void __user *argp) 
	return 0;

}



long btrfs_ioctl_space_info(struct btrfs_root *root, void __user *arg)

{

	struct btrfs_ioctl_space_args space_args;

	struct btrfs_ioctl_space_info space;

	struct btrfs_ioctl_space_info *dest;

	struct btrfs_space_info *info;

	int ret = 0;



	if (copy_from_user(&space_args,

			   (struct btrfs_ioctl_space_args __user *)arg,

			   sizeof(space_args)))

		return -EFAULT;



	space_args.total_spaces = 0;

	dest = (struct btrfs_ioctl_space_info *)

		(arg + sizeof(struct btrfs_ioctl_space_args));



	rcu_read_lock();

	list_for_each_entry_rcu(info, &root->fs_info->space_info, list) {

		if (!space_args.space_slots) {

			space_args.total_spaces++;

			continue;

		}

		if (space_args.total_spaces >= space_args.space_slots)

			break;

		space.flags = info->flags;

		space.total_bytes = info->total_bytes;

		space.used_bytes = info->bytes_used;

		if (copy_to_user(dest, &space, sizeof(space))) {

			ret = -EFAULT;

			break;

		}

		dest++;

		space_args.total_spaces++;

	}

	rcu_read_unlock();



	if (copy_to_user(arg, &space_args, sizeof(space_args)))

		ret = -EFAULT;



	return ret;

}



/*

 * there are many ways the trans_start and trans_end ioctls can lead

 * to deadlocks.  They should only be used by applications that
@@ -1915,6 +1958,8 @@ long btrfs_ioctl(struct file *file, unsigned int 
		return btrfs_ioctl_tree_search(file, argp);

	case BTRFS_IOC_INO_LOOKUP:

		return btrfs_ioctl_ino_lookup(file, argp);

	case BTRFS_IOC_SPACE_INFO:

		return btrfs_ioctl_space_info(root, argp);

	case BTRFS_IOC_SYNC:

		btrfs_sync_fs(file->f_dentry->d_sb, 1);

		return 0;

fs/btrfs/ioctl.h

+13 −1
Original line number Diff line number Diff line 


/*

 * Copyright (C) 2007 Oracle.  All rights reserved.

 *
@@ -127,6 +126,17 @@ struct btrfs_ioctl_defrag_range_args { 
	__u32 unused[5];

};



struct btrfs_ioctl_space_info {

	u64 flags;

	u64 total_bytes;

	u64 used_bytes;

};



struct btrfs_ioctl_space_args {

	u64 space_slots;

	u64 total_spaces;

	struct btrfs_ioctl_space_info spaces[0];

};



#define BTRFS_IOC_SNAP_CREATE _IOW(BTRFS_IOCTL_MAGIC, 1, \

				   struct btrfs_ioctl_vol_args)
@@ -166,4 +176,6 @@ struct btrfs_ioctl_defrag_range_args { 
#define BTRFS_IOC_INO_LOOKUP _IOWR(BTRFS_IOCTL_MAGIC, 18, \

				   struct btrfs_ioctl_ino_lookup_args)

#define BTRFS_IOC_DEFAULT_SUBVOL _IOW(BTRFS_IOCTL_MAGIC, 19, u64)

#define BTRFS_IOC_SPACE_INFO _IOWR(BTRFS_IOCTL_MAGIC, 20, \

				    struct btrfs_ioctl_space_args)

#endif