btrfs: retrieve more info from FS_INFO ioctl

Provide the basic information about filesystem through the ioctl:
* b-tree node size (same as leaf size)
* sector size
* expected alignment of CLONE_RANGE and EXTENT_SAME ioctl arguments

Backward compatibility: if the values are 0, kernel does not provide
this information, the applications should ignore them.

Signed-off-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Chris Mason <clm@fb.com>

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 2f6d7b13b5bdacaba4df505b57b1c3cd9417ee13..c6c8e3560e7377bd7f5fa72b97f43deff61a3146 100644 (file)
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -2574,6 +2574,10 @@ static long btrfs_ioctl_fs_info(struct btrfs_root *root, void __user *arg)
        }
        mutex_unlock(&fs_devices->device_list_mutex);
 
+       fi_args->nodesize = root->fs_info->super_copy->nodesize;
+       fi_args->sectorsize = root->fs_info->super_copy->sectorsize;
+       fi_args->clone_alignment = root->fs_info->super_copy->sectorsize;
+
        if (copy_to_user(arg, fi_args, sizeof(*fi_args)))
                ret = -EFAULT;
 

diff --git a/include/uapi/linux/btrfs.h b/include/uapi/linux/btrfs.h
index 901a3c563f602a955cfb7215d1be648414fd136f..7554fd381a566a8f4a70043365799028377d4037 100644 (file)
--- a/include/uapi/linux/btrfs.h
+++ b/include/uapi/linux/btrfs.h
@@ -181,7 +181,11 @@ 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 */
+       __u32 nodesize;                         /* out */
+       __u32 sectorsize;                       /* out */
+       __u32 clone_alignment;                  /* out */
+       __u32 reserved32;
+       __u64 reserved[122];                    /* pad to 1k */
 };
 
 struct btrfs_ioctl_feature_flags {