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: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

1 files changed, 13 insertions, 1 deletions

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