On 2021/1/6 下午1:04, kernel test robot wrote:

Hi Qu,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on kdave/for-next]
[also build test WARNING on v5.11-rc2 next-20210104]
[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]

url:    https://github.com/0day-ci/linux/commits/Qu-Wenruo/btrfs-add-read-only-support-for-subpage-sector-size/20210106-090847
base:   https://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux.git for-next
config: m68k-randconfig-s032-20210106 (attached as .config)
compiler: m68k-linux-gcc (GCC) 9.3.0
reproduce:
         wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
         chmod +x ~/bin/make.cross
         # apt-get install sparse
         # sparse version: v0.6.3-208-g46a52ca4-dirty
         # https://github.com/0day-ci/linux/commit/2c54bbf363f66a7c4d489fa0b7967ce5fc960afb
         git remote add linux-review https://github.com/0day-ci/linux
         git fetch --no-tags linux-review Qu-Wenruo/btrfs-add-read-only-support-for-subpage-sector-size/20210106-090847
         git checkout 2c54bbf363f66a7c4d489fa0b7967ce5fc960afb
         # save the attached .config to linux build tree
         COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' ARCH=m68k

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <redacted>


"sparse warnings: (new ones prefixed by >>)"

quoted

quoted

fs/btrfs/inode.c:8352:13: sparse: sparse: incorrect type in assignment (different base types) @@     expected restricted vm_fault_t [assigned] [usertype] ret @@     got int @@

    fs/btrfs/inode.c:8352:13: sparse:     expected restricted vm_fault_t [assigned] [usertype] ret
    fs/btrfs/inode.c:8352:13: sparse:     got int

quoted

quoted

fs/btrfs/inode.c:8353:13: sparse: sparse: restricted vm_fault_t degrades to integer

Why I always forgot this...

Now it get properly fixed in github. Although the submitted patch is
still using @ret other than @ret2.

Is there anyway to let LKP to run on specific branch so that I can avoid
similar problems.

Thanks,
Qu

    fs/btrfs/inode.c: note: in included file (through include/linux/mmzone.h, include/linux/gfp.h, include/linux/slab.h, ...):
    include/linux/spinlock.h:394:9: sparse: sparse: context imbalance in 'run_delayed_iput_locked' - unexpected unlock

vim +8352 fs/btrfs/inode.c

   8275
   8276	/*
   8277	 * btrfs_page_mkwrite() is not allowed to change the file size as it gets
   8278	 * called from a page fault handler when a page is first dirtied. Hence we must
   8279	 * be careful to check for EOF conditions here. We set the page up correctly
   8280	 * for a written page which means we get ENOSPC checking when writing into
   8281	 * holes and correct delalloc and unwritten extent mapping on filesystems that
   8282	 * support these features.
   8283	 *
   8284	 * We are not allowed to take the i_mutex here so we have to play games to
   8285	 * protect against truncate races as the page could now be beyond EOF.  Because
   8286	 * truncate_setsize() writes the inode size before removing pages, once we have
   8287	 * the page lock we can determine safely if the page is beyond EOF. If it is not
   8288	 * beyond EOF, then the page is guaranteed safe against truncation until we
   8289	 * unlock the page.
   8290	 */
   8291	vm_fault_t btrfs_page_mkwrite(struct vm_fault *vmf)
   8292	{
   8293		struct page *page = vmf->page;
   8294		struct inode *inode = file_inode(vmf->vma->vm_file);
   8295		struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
   8296		struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
   8297		struct btrfs_ordered_extent *ordered;
   8298		struct extent_state *cached_state = NULL;
   8299		struct extent_changeset *data_reserved = NULL;
   8300		char *kaddr;
   8301		unsigned long zero_start;
   8302		loff_t size;
   8303		vm_fault_t ret;
   8304		int ret2;
   8305		int reserved = 0;
   8306		u64 reserved_space;
   8307		u64 page_start;
   8308		u64 page_end;
   8309		u64 end;
   8310
   8311		reserved_space = PAGE_SIZE;
   8312
   8313		sb_start_pagefault(inode->i_sb);
   8314		page_start = page_offset(page);
   8315		page_end = page_start + PAGE_SIZE - 1;
   8316		end = page_end;
   8317
   8318		/*
   8319		 * Reserving delalloc space after obtaining the page lock can lead to
   8320		 * deadlock. For example, if a dirty page is locked by this function
   8321		 * and the call to btrfs_delalloc_reserve_space() ends up triggering
   8322		 * dirty page write out, then the btrfs_writepage() function could
   8323		 * end up waiting indefinitely to get a lock on the page currently
   8324		 * being processed by btrfs_page_mkwrite() function.
   8325		 */
   8326		ret2 = btrfs_delalloc_reserve_space(BTRFS_I(inode), &data_reserved,
   8327						    page_start, reserved_space);
   8328		if (!ret2) {
   8329			ret2 = file_update_time(vmf->vma->vm_file);
   8330			reserved = 1;
   8331		}
   8332		if (ret2) {
   8333			ret = vmf_error(ret2);
   8334			if (reserved)
   8335				goto out;
   8336			goto out_noreserve;
   8337		}
   8338
   8339		ret = VM_FAULT_NOPAGE; /* make the VM retry the fault */
   8340	again:
   8341		lock_page(page);
   8342		size = i_size_read(inode);
   8343
   8344		if ((page->mapping != inode->i_mapping) ||
   8345		    (page_start >= size)) {
   8346			/* page got truncated out from underneath us */
   8347			goto out_unlock;
   8348		}
   8349		wait_on_page_writeback(page);
   8350
   8351		lock_extent_bits(io_tree, page_start, page_end, &cached_state);

quoted

8352		ret = set_page_extent_mapped(page);
8353		if (ret < 0)

   8354			goto out_unlock;
   8355
   8356		/*
   8357		 * we can't set the delalloc bits if there are pending ordered
   8358		 * extents.  Drop our locks and wait for them to finish
   8359		 */
   8360		ordered = btrfs_lookup_ordered_range(BTRFS_I(inode), page_start,
   8361				PAGE_SIZE);
   8362		if (ordered) {
   8363			unlock_extent_cached(io_tree, page_start, page_end,
   8364					     &cached_state);
   8365			unlock_page(page);
   8366			btrfs_start_ordered_extent(ordered, 1);
   8367			btrfs_put_ordered_extent(ordered);
   8368			goto again;
   8369		}
   8370
   8371		if (page->index == ((size - 1) >> PAGE_SHIFT)) {
   8372			reserved_space = round_up(size - page_start,
   8373						  fs_info->sectorsize);
   8374			if (reserved_space < PAGE_SIZE) {
   8375				end = page_start + reserved_space - 1;
   8376				btrfs_delalloc_release_space(BTRFS_I(inode),
   8377						data_reserved, page_start,
   8378						PAGE_SIZE - reserved_space, true);
   8379			}
   8380		}
   8381
   8382		/*
   8383		 * page_mkwrite gets called when the page is firstly dirtied after it's
   8384		 * faulted in, but write(2) could also dirty a page and set delalloc
   8385		 * bits, thus in this case for space account reason, we still need to
   8386		 * clear any delalloc bits within this page range since we have to
   8387		 * reserve data&meta space before lock_page() (see above comments).
   8388		 */
   8389		clear_extent_bit(&BTRFS_I(inode)->io_tree, page_start, end,
   8390				  EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING |
   8391				  EXTENT_DEFRAG, 0, 0, &cached_state);
   8392
   8393		ret2 = btrfs_set_extent_delalloc(BTRFS_I(inode), page_start, end, 0,
   8394						&cached_state);
   8395		if (ret2) {
   8396			unlock_extent_cached(io_tree, page_start, page_end,
   8397					     &cached_state);
   8398			ret = VM_FAULT_SIGBUS;
   8399			goto out_unlock;
   8400		}
   8401
   8402		/* page is wholly or partially inside EOF */
   8403		if (page_start + PAGE_SIZE > size)
   8404			zero_start = offset_in_page(size);
   8405		else
   8406			zero_start = PAGE_SIZE;
   8407
   8408		if (zero_start != PAGE_SIZE) {
   8409			kaddr = kmap(page);
   8410			memset(kaddr + zero_start, 0, PAGE_SIZE - zero_start);
   8411			flush_dcache_page(page);
   8412			kunmap(page);
   8413		}
   8414		ClearPageChecked(page);
   8415		set_page_dirty(page);
   8416		SetPageUptodate(page);
   8417
   8418		BTRFS_I(inode)->last_trans = fs_info->generation;
   8419		BTRFS_I(inode)->last_sub_trans = BTRFS_I(inode)->root->log_transid;
   8420		BTRFS_I(inode)->last_log_commit = BTRFS_I(inode)->root->last_log_commit;
   8421
   8422		unlock_extent_cached(io_tree, page_start, page_end, &cached_state);
   8423
   8424		btrfs_delalloc_release_extents(BTRFS_I(inode), PAGE_SIZE);
   8425		sb_end_pagefault(inode->i_sb);
   8426		extent_changeset_free(data_reserved);
   8427		return VM_FAULT_LOCKED;
   8428
   8429	out_unlock:
   8430		unlock_page(page);
   8431	out:
   8432		btrfs_delalloc_release_extents(BTRFS_I(inode), PAGE_SIZE);
   8433		btrfs_delalloc_release_space(BTRFS_I(inode), data_reserved, page_start,
   8434					     reserved_space, (ret != 0));
   8435	out_noreserve:
   8436		sb_end_pagefault(inode->i_sb);
   8437		extent_changeset_free(data_reserved);
   8438		return ret;
   8439	}
   8440

---
0-DAY CI Kernel Test Service, Intel Corporation
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