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authorJeff Mahoney <jeffm@suse.com>2013-11-01 21:07:03 +0400
committerChris Mason <clm@fb.com>2014-01-29 01:19:28 +0400
commit01e219e8069516cdb98594d417b8bb8d906ed30d (patch)
tree0e8ff696017353a46d442bff736050ad451f6f8d
parent3b02a68a636400590dd6831a5fc046f0a7909a77 (diff)
downloadlinux-01e219e8069516cdb98594d417b8bb8d906ed30d.tar.xz
btrfs: add ioctl to export size of global metadata reservation
btrfs filesystem df output will show the size of the metadata space and how much of it is used, and the user assumes that the difference is all usable space. Since that's not actually the case due to the global metadata reservation, we should provide the full picture to the user. This patch adds an ioctl that exports the size of the global metadata reservation so that btrfs filesystem df can report it. Signed-off-by: Jeff Mahoney <jeffm@suse.com> Signed-off-by: Josef Bacik <jbacik@fusionio.com> Signed-off-by: Chris Mason <clm@fb.com>
-rw-r--r--fs/btrfs/ioctl.c16
-rw-r--r--include/uapi/linux/btrfs.h1
2 files changed, 17 insertions, 0 deletions
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 93b01fe6c731..60d3d37ef9a2 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -3498,6 +3498,20 @@ out:
return ret;
}
+static long btrfs_ioctl_global_rsv(struct btrfs_root *root, void __user *arg)
+{
+ struct btrfs_block_rsv *block_rsv = &root->fs_info->global_block_rsv;
+ u64 reserved;
+
+ spin_lock(&block_rsv->lock);
+ reserved = block_rsv->reserved;
+ spin_unlock(&block_rsv->lock);
+
+ if (arg && copy_to_user(arg, &reserved, sizeof(reserved)))
+ return -EFAULT;
+ return 0;
+}
+
/*
* there are many ways the trans_start and trans_end ioctls can lead
* to deadlocks. They should only be used by applications that
@@ -4706,6 +4720,8 @@ long btrfs_ioctl(struct file *file, unsigned int
return btrfs_ioctl_logical_to_ino(root, argp);
case BTRFS_IOC_SPACE_INFO:
return btrfs_ioctl_space_info(root, argp);
+ case BTRFS_IOC_GLOBAL_RSV:
+ return btrfs_ioctl_global_rsv(root, argp);
case BTRFS_IOC_SYNC: {
int ret;
diff --git a/include/uapi/linux/btrfs.h b/include/uapi/linux/btrfs.h
index b4d69092fbdb..1b8a0f4c9590 100644
--- a/include/uapi/linux/btrfs.h
+++ b/include/uapi/linux/btrfs.h
@@ -558,6 +558,7 @@ static inline char *btrfs_err_str(enum btrfs_err_code err_code)
#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)
+#define BTRFS_IOC_GLOBAL_RSV _IOR(BTRFS_IOCTL_MAGIC, 20, __u64)
#define BTRFS_IOC_START_SYNC _IOR(BTRFS_IOCTL_MAGIC, 24, __u64)
#define BTRFS_IOC_WAIT_SYNC _IOW(BTRFS_IOCTL_MAGIC, 22, __u64)
#define BTRFS_IOC_SNAP_CREATE_V2 _IOW(BTRFS_IOCTL_MAGIC, 23, \