diff options
| -rw-r--r-- | fs/btrfs/ioctl.c | 121 | ||||
| -rw-r--r-- | include/uapi/linux/btrfs.h | 62 |
2 files changed, 183 insertions, 0 deletions
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index 4db2446c7015..42ed752288e6 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -2383,6 +2383,125 @@ out: return ret; } +/* Get the subvolume information in BTRFS_ROOT_ITEM and BTRFS_ROOT_BACKREF */ +static int btrfs_ioctl_get_subvol_info(struct file *file, void __user *argp) +{ + struct btrfs_ioctl_get_subvol_info_args *subvol_info; + struct btrfs_fs_info *fs_info; + struct btrfs_root *root; + struct btrfs_path *path; + struct btrfs_key key; + struct btrfs_root_item *root_item; + struct btrfs_root_ref *rref; + struct extent_buffer *leaf; + unsigned long item_off; + unsigned long item_len; + struct inode *inode; + int slot; + int ret = 0; + + path = btrfs_alloc_path(); + if (!path) + return -ENOMEM; + + subvol_info = kzalloc(sizeof(*subvol_info), GFP_KERNEL); + if (!subvol_info) { + btrfs_free_path(path); + return -ENOMEM; + } + + inode = file_inode(file); + fs_info = BTRFS_I(inode)->root->fs_info; + + /* Get root_item of inode's subvolume */ + key.objectid = BTRFS_I(inode)->root->root_key.objectid; + key.type = BTRFS_ROOT_ITEM_KEY; + key.offset = (u64)-1; + root = btrfs_read_fs_root_no_name(fs_info, &key); + if (IS_ERR(root)) { + ret = PTR_ERR(root); + goto out; + } + root_item = &root->root_item; + + subvol_info->treeid = key.objectid; + + subvol_info->generation = btrfs_root_generation(root_item); + subvol_info->flags = btrfs_root_flags(root_item); + + memcpy(subvol_info->uuid, root_item->uuid, BTRFS_UUID_SIZE); + memcpy(subvol_info->parent_uuid, root_item->parent_uuid, + BTRFS_UUID_SIZE); + memcpy(subvol_info->received_uuid, root_item->received_uuid, + BTRFS_UUID_SIZE); + + subvol_info->ctransid = btrfs_root_ctransid(root_item); + subvol_info->ctime.sec = btrfs_stack_timespec_sec(&root_item->ctime); + subvol_info->ctime.nsec = btrfs_stack_timespec_nsec(&root_item->ctime); + + subvol_info->otransid = btrfs_root_otransid(root_item); + subvol_info->otime.sec = btrfs_stack_timespec_sec(&root_item->otime); + subvol_info->otime.nsec = btrfs_stack_timespec_nsec(&root_item->otime); + + subvol_info->stransid = btrfs_root_stransid(root_item); + subvol_info->stime.sec = btrfs_stack_timespec_sec(&root_item->stime); + subvol_info->stime.nsec = btrfs_stack_timespec_nsec(&root_item->stime); + + subvol_info->rtransid = btrfs_root_rtransid(root_item); + subvol_info->rtime.sec = btrfs_stack_timespec_sec(&root_item->rtime); + subvol_info->rtime.nsec = btrfs_stack_timespec_nsec(&root_item->rtime); + + if (key.objectid != BTRFS_FS_TREE_OBJECTID) { + /* Search root tree for ROOT_BACKREF of this subvolume */ + root = fs_info->tree_root; + + key.type = BTRFS_ROOT_BACKREF_KEY; + key.offset = 0; + ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); + if (ret < 0) { + goto out; + } else if (path->slots[0] >= + btrfs_header_nritems(path->nodes[0])) { + ret = btrfs_next_leaf(root, path); + if (ret < 0) { + goto out; + } else if (ret > 0) { + ret = -EUCLEAN; + goto out; + } + } + + leaf = path->nodes[0]; + slot = path->slots[0]; + btrfs_item_key_to_cpu(leaf, &key, slot); + if (key.objectid == subvol_info->treeid && + key.type == BTRFS_ROOT_BACKREF_KEY) { + subvol_info->parent_id = key.offset; + + rref = btrfs_item_ptr(leaf, slot, struct btrfs_root_ref); + subvol_info->dirid = btrfs_root_ref_dirid(leaf, rref); + + item_off = btrfs_item_ptr_offset(leaf, slot) + + sizeof(struct btrfs_root_ref); + item_len = btrfs_item_size_nr(leaf, slot) + - sizeof(struct btrfs_root_ref); + read_extent_buffer(leaf, subvol_info->name, + item_off, item_len); + } else { + ret = -ENOENT; + goto out; + } + } + + if (copy_to_user(argp, subvol_info, sizeof(*subvol_info))) + ret = -EFAULT; + +out: + btrfs_free_path(path); + kzfree(subvol_info); + return ret; +} + static noinline int btrfs_ioctl_snap_destroy(struct file *file, void __user *arg) { @@ -5545,6 +5664,8 @@ long btrfs_ioctl(struct file *file, unsigned int return btrfs_ioctl_fsgetxattr(file, argp); case FS_IOC_FSSETXATTR: return btrfs_ioctl_fssetxattr(file, argp); + case BTRFS_IOC_GET_SUBVOL_INFO: + return btrfs_ioctl_get_subvol_info(file, argp); } return -ENOTTY; diff --git a/include/uapi/linux/btrfs.h b/include/uapi/linux/btrfs.h index c8d99b9ca550..f8f20d72b852 100644 --- a/include/uapi/linux/btrfs.h +++ b/include/uapi/linux/btrfs.h @@ -725,6 +725,66 @@ struct btrfs_ioctl_send_args { __u64 reserved[4]; /* in */ }; +/* + * Information about a fs tree root. + * + * All items are filled by the ioctl + */ +struct btrfs_ioctl_get_subvol_info_args { + /* Id of this subvolume */ + __u64 treeid; + + /* Name of this subvolume, used to get the real name at mount point */ + char name[BTRFS_VOL_NAME_MAX + 1]; + + /* + * Id of the subvolume which contains this subvolume. + * Zero for top-level subvolume or a deleted subvolume. + */ + __u64 parent_id; + + /* + * Inode number of the directory which contains this subvolume. + * Zero for top-level subvolume or a deleted subvolume + */ + __u64 dirid; + + /* Latest transaction id of this subvolume */ + __u64 generation; + + /* Flags of this subvolume */ + __u64 flags; + + /* UUID of this subvolume */ + __u8 uuid[BTRFS_UUID_SIZE]; + + /* + * UUID of the subvolume of which this subvolume is a snapshot. + * All zero for a non-snapshot subvolume. + */ + __u8 parent_uuid[BTRFS_UUID_SIZE]; + + /* + * UUID of the subvolume from which this subvolume was received. + * All zero for non-received subvolume. + */ + __u8 received_uuid[BTRFS_UUID_SIZE]; + + /* Transaction id indicating when change/create/send/receive happened */ + __u64 ctransid; + __u64 otransid; + __u64 stransid; + __u64 rtransid; + /* Time corresponding to c/o/s/rtransid */ + struct btrfs_ioctl_timespec ctime; + struct btrfs_ioctl_timespec otime; + struct btrfs_ioctl_timespec stime; + struct btrfs_ioctl_timespec rtime; + + /* Must be zero */ + __u64 reserved[8]; +}; + /* Error codes as returned by the kernel */ enum btrfs_err_code { BTRFS_ERROR_DEV_RAID1_MIN_NOT_MET = 1, @@ -843,5 +903,7 @@ enum btrfs_err_code { struct btrfs_ioctl_vol_args_v2) #define BTRFS_IOC_LOGICAL_INO_V2 _IOWR(BTRFS_IOCTL_MAGIC, 59, \ struct btrfs_ioctl_logical_ino_args) +#define BTRFS_IOC_GET_SUBVOL_INFO _IOR(BTRFS_IOCTL_MAGIC, 60, \ + struct btrfs_ioctl_get_subvol_info_args) #endif /* _UAPI_LINUX_BTRFS_H */ |