From 9a85b7db02952bb04aad39adb2da96d7c53f9ad1 Mon Sep 17 00:00:00 2001 From: Qu Wenruo Date: Tue, 31 Dec 2019 15:12:16 +0800 Subject: [PATCH] btrfs-progs: check: Initialize extent_record::generation member [BUG] When using `btrfs check --init-extent-tree`, there is a pretty high chance that the result fs can't pass tree-checker: BTRFS critical (device dm-3): corrupt leaf: block=5390336 slot=149 extent bytenr=20115456 len=4096 invalid generation, have 16384 expect (0, 360] BTRFS error (device dm-3): block=5390336 read time tree block corruption detected BTRFS error (device dm-3): failed to read block groups: -5 BTRFS error (device dm-3): open_ctree failed [CAUSE] The result fs has a pretty screwed up EXTENT_ITEMs for data extents: item 148 key (20111360 EXTENT_ITEM 4096) itemoff 8777 itemsize 53 refs 1 gen 0 flags DATA extent data backref root FS_TREE objectid 841 offset 0 count 1 item 149 key (20115456 EXTENT_ITEM 4096) itemoff 8724 itemsize 53 refs 1 gen 16384 flags DATA extent data backref root FS_TREE objectid 906 offset 0 count 1 Kernel tree-checker will accept 0 generation, but that 16384 generation is definitely going to trigger the alarm. Looking into the code, it's add_extent_rec_nolookup() allocating a new extent_rec, but not copying all members from parameter @tmpl, resulting generation not properly initialized. [FIX] Just copy tmpl->generation in add_extent_rec_nolookup(). And since all call sites have set all members of @tmpl to 0 before add_extent_rec_nolookup(), we shouldn't get garbage values. For the 0 generation problem, it will be solved in another patch. Issue: #225 (Not the initial report, but extent tree rebuild result) Reviewed-by: Su Yue Signed-off-by: Qu Wenruo Signed-off-by: David Sterba --- check/main.c | 1 + 1 file changed, 1 insertion(+) diff --git a/check/main.c b/check/main.c index 5036363c..1537ed3e 100644 --- a/check/main.c +++ b/check/main.c @@ -4605,6 +4605,7 @@ static int add_extent_rec_nolookup(struct cache_tree *extent_cache, rec->refs = tmpl->refs; rec->extent_item_refs = tmpl->extent_item_refs; rec->parent_generation = tmpl->parent_generation; + rec->generation = tmpl->generation; INIT_LIST_HEAD(&rec->backrefs); INIT_LIST_HEAD(&rec->dups); INIT_LIST_HEAD(&rec->list);