Hi Anand, Thank you for the patch! Yet something to improve: [auto build test ERROR on btrfs/next] [also build test ERROR on v4.14 next-20171114] [if your patch is applied to the wrong git tree, please drop us a note to help improve the system] url: https://github.com/0day-ci/linux/commits/Anand-Jain/btrfs-handle-dynamically-reappearing-missing-device/20171115-143047 base: https://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs.git next config: sparc64-allyesconfig (attached as .config) compiler: sparc64-linux-gnu-gcc (Debian 7.2.0-11) 7.2.0 reproduce: wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # save the attached .config to linux build tree make.cross ARCH=sparc64 All errors (new ones prefixed by >>): fs/btrfs/volumes.c: In function 'device_list_add': >> fs/btrfs/volumes.c:732:10: error: implicit declaration of function 'btrfs_open_one_device'; did you mean 'btrfs_scan_one_device'? [-Werror=implicit-function-declaration] ret = btrfs_open_one_device(fs_devices, device, fmode, ^~~~~~~~~~~~~~~~~~~~~ btrfs_scan_one_device cc1: some warnings being treated as errors vim +732 fs/btrfs/volumes.c 610 611 /* 612 * Add new device to list of registered devices 613 * 614 * Returns: 615 * 1 - first time device is seen 616 * 0 - device already known 617 * < 0 - error 618 */ 619 static noinline int device_list_add(const char *path, 620 struct btrfs_super_block *disk_super, 621 u64 devid, struct btrfs_fs_devices **fs_devices_ret) 622 { 623 struct btrfs_device *device; 624 struct btrfs_fs_devices *fs_devices; 625 struct rcu_string *name; 626 int ret = 0; 627 u64 found_transid = btrfs_super_generation(disk_super); 628 629 fs_devices = find_fsid(disk_super->fsid); 630 if (!fs_devices) { 631 fs_devices = alloc_fs_devices(disk_super->fsid); 632 if (IS_ERR(fs_devices)) 633 return PTR_ERR(fs_devices); 634 635 list_add(&fs_devices->list, &fs_uuids); 636 637 device = NULL; 638 } else { 639 device = __find_device(&fs_devices->devices, devid, 640 disk_super->dev_item.uuid); 641 } 642 643 if (!device) { 644 if (fs_devices->opened) 645 return -EBUSY; 646 647 device = btrfs_alloc_device(NULL, &devid, 648 disk_super->dev_item.uuid); 649 if (IS_ERR(device)) { 650 /* we can safely leave the fs_devices entry around */ 651 return PTR_ERR(device); 652 } 653 654 name = rcu_string_strdup(path, GFP_NOFS); 655 if (!name) { 656 kfree(device); 657 return -ENOMEM; 658 } 659 rcu_assign_pointer(device->name, name); 660 661 mutex_lock(&fs_devices->device_list_mutex); 662 list_add_rcu(&device->dev_list, &fs_devices->devices); 663 fs_devices->num_devices++; 664 mutex_unlock(&fs_devices->device_list_mutex); 665 666 ret = 1; 667 device->fs_devices = fs_devices; 668 } else if (!device->name || strcmp(device->name->str, path)) { 669 /* 670 * When FS is already mounted. 671 * 1. If you are here and if the device->name is NULL that 672 * means this device was missing at time of FS mount. 673 * 2. If you are here and if the device->name is different 674 * from 'path' that means either 675 * a. The same device disappeared and reappeared with 676 * different name. or 677 * b. The missing-disk-which-was-replaced, has 678 * reappeared now. 679 * 680 * We must allow 1 and 2a above. But 2b would be a spurious 681 * and unintentional. 682 * 683 * Further in case of 1 and 2a above, the disk at 'path' 684 * would have missed some transaction when it was away and 685 * in case of 2a the stale bdev has to be updated as well. 686 * 2b must not be allowed at all time. 687 */ 688 689 /* 690 * For now, we do allow update to btrfs_fs_device through the 691 * btrfs dev scan cli after FS has been mounted. We're still 692 * tracking a problem where systems fail mount by subvolume id 693 * when we reject replacement on a mounted FS. 694 */ 695 if (!fs_devices->opened && found_transid < device->generation) { 696 /* 697 * That is if the FS is _not_ mounted and if you 698 * are here, that means there is more than one 699 * disk with same uuid and devid.We keep the one 700 * with larger generation number or the last-in if 701 * generation are equal. 702 */ 703 return -EEXIST; 704 } 705 706 name = rcu_string_strdup(path, GFP_NOFS); 707 if (!name) 708 return -ENOMEM; 709 rcu_string_free(device->name); 710 rcu_assign_pointer(device->name, name); 711 if (device->missing) { 712 int ret; 713 struct btrfs_fs_info *fs_info = fs_devices->fs_info; 714 fmode_t fmode = FMODE_READ | FMODE_WRITE | FMODE_EXCL; 715 716 if (btrfs_super_flags(disk_super) & BTRFS_SUPER_FLAG_SEEDING) 717 fmode &= ~FMODE_WRITE; 718 719 /* 720 * Missing can be set only when FS is mounted. 721 * So here its always fs_devices->opened > 0 and most 722 * of the struct device members are already updated by 723 * the mount process even if this device was missing, so 724 * now follow the normal open device procedure for this 725 * device. The scrub will take care of filling the 726 * missing stripes for raid56 and balance for raid1 and 727 * raid10. 728 */ 729 ASSERT(fs_devices->opened); 730 mutex_lock(&fs_devices->device_list_mutex); 731 mutex_lock(&fs_info->chunk_mutex); > 732 ret = btrfs_open_one_device(fs_devices, device, fmode, 733 fs_info->bdev_holder); 734 if (!ret) { 735 fs_devices->missing_devices--; 736 device->missing = 0; 737 btrfs_clear_opt(fs_info->mount_opt, DEGRADED); 738 btrfs_warn(fs_info, 739 "BTRFS: device %s devid %llu uuid %pU joined\n", 740 path, devid, device->uuid); 741 } 742 743 if (device->writeable && 744 !device->is_tgtdev_for_dev_replace) { 745 fs_devices->total_rw_bytes += device->total_bytes; 746 atomic64_add(device->total_bytes - 747 device->bytes_used, 748 &fs_info->free_chunk_space); 749 } 750 device->in_fs_metadata = 1; 751 mutex_unlock(&fs_devices->fs_info->chunk_mutex); 752 mutex_unlock(&fs_devices->device_list_mutex); 753 } 754 } 755 756 /* 757 * Unmount does not free the btrfs_device struct but would zero 758 * generation along with most of the other members. So just update 759 * it back. We need it to pick the disk with largest generation 760 * (as above). 761 */ 762 if (!fs_devices->opened) 763 device->generation = found_transid; 764 765 /* 766 * if there is new btrfs on an already registered device, 767 * then remove the stale device entry. 768 */ 769 if (ret > 0) 770 btrfs_free_stale_device(device); 771 772 *fs_devices_ret = fs_devices; 773 774 return ret; 775 } 776 --- 0-DAY kernel test infrastructure Open Source Technology Center https://lists.01.org/pipermail/kbuild-all Intel Corporation
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