diff options
Diffstat (limited to 'fs/btrfs/ioctl.c')
| -rw-r--r-- | fs/btrfs/ioctl.c | 142 |
1 files changed, 142 insertions, 0 deletions
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index 21da5762b0b1..d4e105b54091 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -4480,6 +4480,142 @@ out_unlock: return ret; } +#define INIT_FEATURE_FLAGS(suffix) \ + { .compat_flags = BTRFS_FEATURE_COMPAT_##suffix, \ + .compat_ro_flags = BTRFS_FEATURE_COMPAT_RO_##suffix, \ + .incompat_flags = BTRFS_FEATURE_INCOMPAT_##suffix } + +static int btrfs_ioctl_get_supported_features(struct file *file, + void __user *arg) +{ + static struct btrfs_ioctl_feature_flags features[3] = { + INIT_FEATURE_FLAGS(SUPP), + INIT_FEATURE_FLAGS(SAFE_SET), + INIT_FEATURE_FLAGS(SAFE_CLEAR) + }; + + if (copy_to_user(arg, &features, sizeof(features))) + return -EFAULT; + + return 0; +} + +static int btrfs_ioctl_get_features(struct file *file, void __user *arg) +{ + struct btrfs_root *root = BTRFS_I(file_inode(file))->root; + struct btrfs_super_block *super_block = root->fs_info->super_copy; + struct btrfs_ioctl_feature_flags features; + + features.compat_flags = btrfs_super_compat_flags(super_block); + features.compat_ro_flags = btrfs_super_compat_ro_flags(super_block); + features.incompat_flags = btrfs_super_incompat_flags(super_block); + + if (copy_to_user(arg, &features, sizeof(features))) + return -EFAULT; + + return 0; +} + +static int check_feature_bits(struct btrfs_root *root, const char *type, + u64 change_mask, u64 flags, u64 supported_flags, + u64 safe_set, u64 safe_clear) +{ + u64 disallowed, unsupported; + u64 set_mask = flags & change_mask; + u64 clear_mask = ~flags & change_mask; + + unsupported = set_mask & ~supported_flags; + if (unsupported) { + btrfs_warn(root->fs_info, + "this kernel does not support %s bits 0x%llx", + type, unsupported); + return -EOPNOTSUPP; + } + + disallowed = set_mask & ~safe_set; + if (disallowed) { + btrfs_warn(root->fs_info, + "can't set %s bits 0x%llx while mounted", + type, disallowed); + return -EPERM; + } + + disallowed = clear_mask & ~safe_clear; + if (disallowed) { + btrfs_warn(root->fs_info, + "can't clear %s bits 0x%llx while mounted", + type, disallowed); + return -EPERM; + } + + return 0; +} + +#define check_feature(root, change_mask, flags, mask_base) \ +check_feature_bits(root, # mask_base, change_mask, flags, \ + BTRFS_FEATURE_ ## mask_base ## _SUPP, \ + BTRFS_FEATURE_ ## mask_base ## _SAFE_SET, \ + BTRFS_FEATURE_ ## mask_base ## _SAFE_CLEAR) + +static int btrfs_ioctl_set_features(struct file *file, void __user *arg) +{ + struct btrfs_root *root = BTRFS_I(file_inode(file))->root; + struct btrfs_super_block *super_block = root->fs_info->super_copy; + struct btrfs_ioctl_feature_flags flags[2]; + struct btrfs_trans_handle *trans; + u64 newflags; + int ret; + + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + + if (copy_from_user(flags, arg, sizeof(flags))) + return -EFAULT; + + /* Nothing to do */ + if (!flags[0].compat_flags && !flags[0].compat_ro_flags && + !flags[0].incompat_flags) + return 0; + + ret = check_feature(root, flags[0].compat_flags, + flags[1].compat_flags, COMPAT); + if (ret) + return ret; + + ret = check_feature(root, flags[0].compat_ro_flags, + flags[1].compat_ro_flags, COMPAT_RO); + if (ret) + return ret; + + ret = check_feature(root, flags[0].incompat_flags, + flags[1].incompat_flags, INCOMPAT); + if (ret) + return ret; + + trans = btrfs_start_transaction(root, 1); + if (IS_ERR(trans)) + return PTR_ERR(trans); + + spin_lock(&root->fs_info->super_lock); + newflags = btrfs_super_compat_flags(super_block); + newflags |= flags[0].compat_flags & flags[1].compat_flags; + newflags &= ~(flags[0].compat_flags & ~flags[1].compat_flags); + btrfs_set_super_compat_flags(super_block, newflags); + + newflags = btrfs_super_compat_ro_flags(super_block); + newflags |= flags[0].compat_ro_flags & flags[1].compat_ro_flags; + newflags &= ~(flags[0].compat_ro_flags & ~flags[1].compat_ro_flags); + btrfs_set_super_compat_ro_flags(super_block, newflags); + + newflags = btrfs_super_incompat_flags(super_block); + newflags |= flags[0].incompat_flags & flags[1].incompat_flags; + newflags &= ~(flags[0].incompat_flags & ~flags[1].incompat_flags); + btrfs_set_super_incompat_flags(super_block, newflags); + spin_unlock(&root->fs_info->super_lock); + + return btrfs_end_transaction(trans, root); +} + long btrfs_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { @@ -4598,6 +4734,12 @@ long btrfs_ioctl(struct file *file, unsigned int return btrfs_ioctl_set_fslabel(file, argp); case BTRFS_IOC_FILE_EXTENT_SAME: return btrfs_ioctl_file_extent_same(file, argp); + case BTRFS_IOC_GET_SUPPORTED_FEATURES: + return btrfs_ioctl_get_supported_features(file, argp); + case BTRFS_IOC_GET_FEATURES: + return btrfs_ioctl_get_features(file, argp); + case BTRFS_IOC_SET_FEATURES: + return btrfs_ioctl_set_features(file, argp); } return -ENOTTY; |