2 files changed, 58 insertions, 1 deletions

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 9aaba6e472d3..9213d39d36cc 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -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;
diff --git a/fs/btrfs/ioctl.h b/fs/btrfs/ioctl.h
index 2d64a65842f3..81eac0a59ea3 100644
--- a/fs/btrfs/ioctl.h
+++ b/fs/btrfs/ioctl.h
@@ -1,4 +1,3 @@
-
 /*
  * 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