btrfs-progs has to read fs info from the kernel to
read the latest info instead of reading it from the disks,
which generally is a stale info after certain critical
operation.
getting used_bytes parameter will help to fix
btrfs filesystem show --kernel
to show the current info of the fs
v2->v3:
everything is changed dropped the plan to introduce
the new ioctl, as of now filesystem show could
manage if we add the used_bytes parameter to the
BTRFS_IOC_FS_INFO and
Update the title from
add framework to read fs info and dev info from the kernel
Signed-off-by: Anand Jain <anand.jain@xxxxxxxxxx>
---
fs/btrfs/ioctl.c | 16 ++++++++++++++--
include/uapi/linux/btrfs.h | 3 ++-
2 files changed, 16 insertions(+), 3 deletions(-)
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 0e7bcc5..082c9fc 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -2384,7 +2384,10 @@ static long btrfs_ioctl_fs_info(struct btrfs_root *root, void __user *arg)
struct btrfs_ioctl_fs_info_args *fi_args;
struct btrfs_device *device;
struct btrfs_device *next;
- struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
+ struct btrfs_fs_info *info = root->fs_info;
+ struct btrfs_fs_devices *fs_devices = info->fs_devices;
+ struct btrfs_space_info *si;
+ u64 used_bytes = 0;
int ret = 0;
if (!capable(CAP_SYS_ADMIN))
@@ -2394,8 +2397,17 @@ static long btrfs_ioctl_fs_info(struct btrfs_root *root, void __user *arg)
if (!fi_args)
return -ENOMEM;
+ rcu_read_lock();
+ list_for_each_entry_rcu(si, &info->space_info, list) {
+ used_bytes += si->bytes_used + si->bytes_reserved
+ + si->bytes_pinned + si->bytes_readonly
+ + si->bytes_may_use;
+ }
+ rcu_read_unlock();
+ fi_args->used_bytes = used_bytes;
+
fi_args->num_devices = fs_devices->num_devices;
- memcpy(&fi_args->fsid, root->fs_info->fsid, sizeof(fi_args->fsid));
+ memcpy(&fi_args->fsid, info->fsid, sizeof(fi_args->fsid));
mutex_lock(&fs_devices->device_list_mutex);
list_for_each_entry_safe(device, next, &fs_devices->devices, dev_list) {
diff --git a/include/uapi/linux/btrfs.h b/include/uapi/linux/btrfs.h
index de3ec34..44bac0c 100644
--- a/include/uapi/linux/btrfs.h
+++ b/include/uapi/linux/btrfs.h
@@ -181,7 +181,8 @@ struct btrfs_ioctl_fs_info_args {
__u64 max_id; /* out */
__u64 num_devices; /* out */
__u8 fsid[BTRFS_FSID_SIZE]; /* out */
- __u64 reserved[124]; /* pad to 1k */
+ __u64 used_bytes; /* out */
+ __u64 reserved[123]; /* pad to 1k */
};
/* balance control ioctl modes */
--
1.8.1.227.g44fe835
--
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