tree: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master head: 761914dd2975bc443024f0ec10a66a26b7186ec2 commit: 0d3e622b2ac768ac5a94f8d9ede80a051154ea9e [10644/11012] ocfs2: try to reuse extent block in dealloc without meta_alloc New smatch warnings: fs/ocfs2/alloc.c:6761 ocfs2_reuse_blk_from_dealloc() warn: potentially one past the end of array 'new_eb_bh[i]' fs/ocfs2/alloc.c:6761 ocfs2_reuse_blk_from_dealloc() warn: potentially one past the end of array 'new_eb_bh[i]' Old smatch warnings: fs/ocfs2/alloc.c:6762 ocfs2_reuse_blk_from_dealloc() warn: potentially one past the end of array 'new_eb_bh[i]' fs/ocfs2/alloc.c:6762 ocfs2_reuse_blk_from_dealloc() warn: potentially one past the end of array 'new_eb_bh[i]' fs/ocfs2/alloc.c:6887 ocfs2_zero_cluster_pages() warn: should '(page->index + 1) << 12' be a 64 bit type? # https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=0d3e622b2ac768ac5a94f8d9ede80a051154ea9e git remote add linux-next https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git git remote update linux-next git checkout 0d3e622b2ac768ac5a94f8d9ede80a051154ea9e vim +6761 fs/ocfs2/alloc.c 0d3e622b Changwei Ge 2018-01-19 6662 0d3e622b Changwei Ge 2018-01-19 6663 /* If extent was deleted from tree due to extent rotation and merging, and 0d3e622b Changwei Ge 2018-01-19 6664 * no metadata is reserved ahead of time. Try to reuse some extents 0d3e622b Changwei Ge 2018-01-19 6665 * just deleted. This is only used to reuse extent blocks. 0d3e622b Changwei Ge 2018-01-19 6666 * It is supposed to find enough extent blocks in dealloc if our estimation 0d3e622b Changwei Ge 2018-01-19 6667 * on metadata is accurate. 0d3e622b Changwei Ge 2018-01-19 6668 */ 0d3e622b Changwei Ge 2018-01-19 6669 static int ocfs2_reuse_blk_from_dealloc(handle_t *handle, 0d3e622b Changwei Ge 2018-01-19 6670 struct ocfs2_extent_tree *et, 0d3e622b Changwei Ge 2018-01-19 6671 struct buffer_head **new_eb_bh, 0d3e622b Changwei Ge 2018-01-19 6672 int blk_wanted, int *blk_given) 0d3e622b Changwei Ge 2018-01-19 6673 { 0d3e622b Changwei Ge 2018-01-19 6674 int i, status = 0, real_slot; 0d3e622b Changwei Ge 2018-01-19 6675 struct ocfs2_cached_dealloc_ctxt *dealloc; 0d3e622b Changwei Ge 2018-01-19 6676 struct ocfs2_per_slot_free_list *fl; 0d3e622b Changwei Ge 2018-01-19 6677 struct ocfs2_cached_block_free *bf; 0d3e622b Changwei Ge 2018-01-19 6678 struct ocfs2_extent_block *eb; 0d3e622b Changwei Ge 2018-01-19 6679 struct ocfs2_super *osb = 0d3e622b Changwei Ge 2018-01-19 6680 OCFS2_SB(ocfs2_metadata_cache_get_super(et->et_ci)); 0d3e622b Changwei Ge 2018-01-19 6681 0d3e622b Changwei Ge 2018-01-19 6682 *blk_given = 0; 0d3e622b Changwei Ge 2018-01-19 6683 0d3e622b Changwei Ge 2018-01-19 6684 /* If extent tree doesn't have a dealloc, this is not faulty. Just 0d3e622b Changwei Ge 2018-01-19 6685 * tell upper caller dealloc can't provide any block and it should 0d3e622b Changwei Ge 2018-01-19 6686 * ask for alloc to claim more space. 0d3e622b Changwei Ge 2018-01-19 6687 */ 0d3e622b Changwei Ge 2018-01-19 6688 dealloc = et->et_dealloc; 0d3e622b Changwei Ge 2018-01-19 6689 if (!dealloc) 0d3e622b Changwei Ge 2018-01-19 6690 goto bail; 0d3e622b Changwei Ge 2018-01-19 6691 0d3e622b Changwei Ge 2018-01-19 6692 for (i = 0; i < blk_wanted; i++) { 0d3e622b Changwei Ge 2018-01-19 6693 /* Prefer to use local slot */ 0d3e622b Changwei Ge 2018-01-19 6694 fl = ocfs2_find_preferred_free_list(EXTENT_ALLOC_SYSTEM_INODE, 0d3e622b Changwei Ge 2018-01-19 6695 osb->slot_num, &real_slot, 0d3e622b Changwei Ge 2018-01-19 6696 dealloc); 0d3e622b Changwei Ge 2018-01-19 6697 /* If no more block can be reused, we should claim more 0d3e622b Changwei Ge 2018-01-19 6698 * from alloc. Just return here normally. 0d3e622b Changwei Ge 2018-01-19 6699 */ 0d3e622b Changwei Ge 2018-01-19 6700 if (!fl) { 0d3e622b Changwei Ge 2018-01-19 6701 status = 0; 0d3e622b Changwei Ge 2018-01-19 6702 break; 0d3e622b Changwei Ge 2018-01-19 6703 } 0d3e622b Changwei Ge 2018-01-19 6704 0d3e622b Changwei Ge 2018-01-19 6705 bf = fl->f_first; 0d3e622b Changwei Ge 2018-01-19 6706 fl->f_first = bf->free_next; 0d3e622b Changwei Ge 2018-01-19 6707 0d3e622b Changwei Ge 2018-01-19 6708 new_eb_bh[i] = sb_getblk(osb->sb, bf->free_blk); 0d3e622b Changwei Ge 2018-01-19 6709 if (new_eb_bh[i] == NULL) { 0d3e622b Changwei Ge 2018-01-19 6710 status = -ENOMEM; 0d3e622b Changwei Ge 2018-01-19 6711 mlog_errno(status); 0d3e622b Changwei Ge 2018-01-19 6712 goto bail; 0d3e622b Changwei Ge 2018-01-19 6713 } 0d3e622b Changwei Ge 2018-01-19 6714 0d3e622b Changwei Ge 2018-01-19 6715 mlog(0, "Reusing block(%llu) from " 0d3e622b Changwei Ge 2018-01-19 6716 "dealloc(local slot:%d, real slot:%d)\n", 0d3e622b Changwei Ge 2018-01-19 6717 bf->free_blk, osb->slot_num, real_slot); 0d3e622b Changwei Ge 2018-01-19 6718 0d3e622b Changwei Ge 2018-01-19 6719 ocfs2_set_new_buffer_uptodate(et->et_ci, new_eb_bh[i]); 0d3e622b Changwei Ge 2018-01-19 6720 0d3e622b Changwei Ge 2018-01-19 6721 status = ocfs2_journal_access_eb(handle, et->et_ci, 0d3e622b Changwei Ge 2018-01-19 6722 new_eb_bh[i], 0d3e622b Changwei Ge 2018-01-19 6723 OCFS2_JOURNAL_ACCESS_CREATE); 0d3e622b Changwei Ge 2018-01-19 6724 if (status < 0) { ^^^^^^^^^^ The warning is a false positive. It's caused because the check here is for less than zero and the check at the end is for non-zero. The static checker is thinking that status can be > 0 here. If both checks were written the same way, that would silence the warning. Also if you rebuild your cross function DB a bunch of time that silences the warning because then Smatch know that ocfs2_journal_access_eb() returns (-30),(-22),(-5), or 0. I rebuild my DB every morning on the latest linux-next so I don't see this warning on my system. 0d3e622b Changwei Ge 2018-01-19 6725 mlog_errno(status); 0d3e622b Changwei Ge 2018-01-19 6726 goto bail; 0d3e622b Changwei Ge 2018-01-19 6727 } 0d3e622b Changwei Ge 2018-01-19 6728 0d3e622b Changwei Ge 2018-01-19 6729 memset(new_eb_bh[i]->b_data, 0, osb->sb->s_blocksize); 0d3e622b Changwei Ge 2018-01-19 6730 eb = (struct ocfs2_extent_block *) new_eb_bh[i]->b_data; 0d3e622b Changwei Ge 2018-01-19 6731 0d3e622b Changwei Ge 2018-01-19 6732 /* We can't guarantee that buffer head is still cached, so 0d3e622b Changwei Ge 2018-01-19 6733 * polutlate the extent block again. 0d3e622b Changwei Ge 2018-01-19 6734 */ 0d3e622b Changwei Ge 2018-01-19 6735 strcpy(eb->h_signature, OCFS2_EXTENT_BLOCK_SIGNATURE); 0d3e622b Changwei Ge 2018-01-19 6736 eb->h_blkno = cpu_to_le64(bf->free_blk); 0d3e622b Changwei Ge 2018-01-19 6737 eb->h_fs_generation = cpu_to_le32(osb->fs_generation); 0d3e622b Changwei Ge 2018-01-19 6738 eb->h_suballoc_slot = cpu_to_le16(real_slot); 0d3e622b Changwei Ge 2018-01-19 6739 eb->h_suballoc_loc = cpu_to_le64(bf->free_bg); 0d3e622b Changwei Ge 2018-01-19 6740 eb->h_suballoc_bit = cpu_to_le16(bf->free_bit); 0d3e622b Changwei Ge 2018-01-19 6741 eb->h_list.l_count = 0d3e622b Changwei Ge 2018-01-19 6742 cpu_to_le16(ocfs2_extent_recs_per_eb(osb->sb)); 0d3e622b Changwei Ge 2018-01-19 6743 0d3e622b Changwei Ge 2018-01-19 6744 /* We'll also be dirtied by the caller, so 0d3e622b Changwei Ge 2018-01-19 6745 * this isn't absolutely necessary. 0d3e622b Changwei Ge 2018-01-19 6746 */ 0d3e622b Changwei Ge 2018-01-19 6747 ocfs2_journal_dirty(handle, new_eb_bh[i]); 0d3e622b Changwei Ge 2018-01-19 6748 0d3e622b Changwei Ge 2018-01-19 6749 if (!fl->f_first) { 0d3e622b Changwei Ge 2018-01-19 6750 dealloc->c_first_suballocator = fl->f_next_suballocator; 0d3e622b Changwei Ge 2018-01-19 6751 kfree(fl); 0d3e622b Changwei Ge 2018-01-19 6752 } 0d3e622b Changwei Ge 2018-01-19 6753 kfree(bf); 0d3e622b Changwei Ge 2018-01-19 6754 } 0d3e622b Changwei Ge 2018-01-19 6755 0d3e622b Changwei Ge 2018-01-19 6756 *blk_given = i; 0d3e622b Changwei Ge 2018-01-19 6757 0d3e622b Changwei Ge 2018-01-19 6758 bail: 0d3e622b Changwei Ge 2018-01-19 6759 if (unlikely(status)) { ^^^^^^ 0d3e622b Changwei Ge 2018-01-19 6760 for (; i >= 0; i--) { 0d3e622b Changwei Ge 2018-01-19 @6761 if (new_eb_bh[i]) 0d3e622b Changwei Ge 2018-01-19 6762 brelse(new_eb_bh[i]); 0d3e622b Changwei Ge 2018-01-19 6763 } 0d3e622b Changwei Ge 2018-01-19 6764 } 0d3e622b Changwei Ge 2018-01-19 6765 0d3e622b Changwei Ge 2018-01-19 6766 return status; 0d3e622b Changwei Ge 2018-01-19 6767 } 0d3e622b Changwei Ge 2018-01-19 6768 --- 0-DAY kernel test infrastructure Open Source Technology Center https://lists.01.org/pipermail/kbuild-all Intel Corporation -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. 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