Re: [PATCH 2/4] btrfs: make btrfs_repair_io_failure() handle bs > ps cases without large folios

[kernel test robot <lkp@intel.com>]

Hi Qu,

kernel test robot noticed the following build errors:

[auto build test ERROR on kdave/for-next]
[also build test ERROR on linus/master next-20250929]
[cannot apply to v6.17]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Qu-Wenruo/btrfs-make-btrfs_csum_one_bio-handle-bs-ps-without-large-folios/20251001-175128
base:   https://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux.git for-next
patch link:    https://lore.kernel.org/r/33c39907866c148a360ff60387097fbad63a19aa.1759311101.git.wqu%40suse.com
patch subject: [PATCH 2/4] btrfs: make btrfs_repair_io_failure() handle bs > ps cases without large folios
config: i386-randconfig-011-20251002 (https://download.01.org/0day-ci/archive/20251003/202510030041.mTtTa2Pr-lkp@intel.com/config)
compiler: gcc-12 (Debian 12.4.0-5) 12.4.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20251003/202510030041.mTtTa2Pr-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202510030041.mTtTa2Pr-lkp@intel.com/

All errors (new ones prefixed by >>):

   ld: fs/btrfs/bio.o: in function `btrfs_repair_io_failure':
>> fs/btrfs/bio.c:859:(.text+0x188c): undefined reference to `__udivdi3'


vim +859 fs/btrfs/bio.c

   836	
   837	/*
   838	 * Submit a repair write.
   839	 *
   840	 * This bypasses btrfs_submit_bbio() deliberately, as that writes all copies in a
   841	 * RAID setup.  Here we only want to write the one bad copy, so we do the
   842	 * mapping ourselves and submit the bio directly.
   843	 *
   844	 * The I/O is issued synchronously to block the repair read completion from
   845	 * freeing the bio.
   846	 *
   847	 * @ino:	Offending inode number
   848	 * @fileoff:	File offset inside the inode
   849	 * @length:	Length of the repair write
   850	 * @logical:	Logical address of the range
   851	 * @paddrs:	Physical address array of the content.
   852	 *		Length for each paddr should be min(sectorsize, PAGE_SIZE).
   853	 * @mirror_num: Mirror number to write to. Must not be zero.
   854	 */
   855	int btrfs_repair_io_failure(struct btrfs_fs_info *fs_info, u64 ino, u64 fileoff,
   856				    u64 length, u64 logical, const phys_addr_t paddrs[], int mirror_num)
   857	{
   858		const u32 step = min(fs_info->sectorsize, PAGE_SIZE);
 > 859		const u32 nr_steps = DIV_ROUND_UP_POW2(length, step);
   860		struct btrfs_io_stripe smap = { 0 };
   861		struct bio *bio = NULL;
   862		int ret = 0;
   863	
   864		ASSERT(!(fs_info->sb->s_flags & SB_RDONLY));
   865		BUG_ON(!mirror_num);
   866	
   867		/* Basic alignment checks. */
   868		ASSERT(IS_ALIGNED(logical, fs_info->sectorsize));
   869		ASSERT(IS_ALIGNED(length, fs_info->sectorsize));
   870		ASSERT(IS_ALIGNED(fileoff, fs_info->sectorsize));
   871	
   872		if (btrfs_repair_one_zone(fs_info, logical))
   873			return 0;
   874	
   875		/*
   876		 * Avoid races with device replace and make sure our bioc has devices
   877		 * associated to its stripes that don't go away while we are doing the
   878		 * read repair operation.
   879		 */
   880		btrfs_bio_counter_inc_blocked(fs_info);
   881		ret = btrfs_map_repair_block(fs_info, &smap, logical, length, mirror_num);
   882		if (ret < 0)
   883			goto out_counter_dec;
   884	
   885		if (unlikely(!smap.dev->bdev ||
   886			     !test_bit(BTRFS_DEV_STATE_WRITEABLE, &smap.dev->dev_state))) {
   887			ret = -EIO;
   888			goto out_counter_dec;
   889		}
   890	
   891		bio = bio_alloc(smap.dev->bdev, nr_steps, REQ_OP_WRITE | REQ_SYNC, GFP_NOFS);
   892		/* Backed by fs_bio_set, shouldn't fail. */
   893		ASSERT(bio);
   894		bio->bi_iter.bi_sector = smap.physical >> SECTOR_SHIFT;
   895		for (int i = 0; i < nr_steps; i++) {
   896			ret = bio_add_page(bio, phys_to_page(paddrs[i]), step, offset_in_page(paddrs[i]));
   897			/* We should have allocated enough slots to contain all the different pages. */
   898			ASSERT(ret == step);
   899		}
   900		ret = submit_bio_wait(bio);
   901		if (ret) {
   902			/* try to remap that extent elsewhere? */
   903			btrfs_dev_stat_inc_and_print(smap.dev, BTRFS_DEV_STAT_WRITE_ERRS);
   904			goto out_free_bio;
   905		}
   906	
   907		btrfs_info_rl(fs_info,
   908			"read error corrected: ino %llu off %llu (dev %s sector %llu)",
   909				     ino, fileoff, btrfs_dev_name(smap.dev),
   910				     smap.physical >> SECTOR_SHIFT);
   911		ret = 0;
   912	
   913	out_free_bio:
   914		if (bio)
   915			bio_put(bio);
   916	out_counter_dec:
   917		btrfs_bio_counter_dec(fs_info);
   918		return ret;
   919	}
   920	

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