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Btrfs: add a "df" ioctl for btrfs

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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: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
This commit is contained in:
Josef Bacik
2010-01-13 18:19:06 +00:00
committed by Chris Mason
parent 2ac55d41b5
commit 1406e4327b
2 changed files with 58 additions and 1 deletions
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45
fs/btrfs/ioctl.c
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@@ -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;