My experience/interpretation of the 2 checks is that it is OK, see some more comments inserted below. Hopefully a developer of btrfs-progs can comment in more detail.
> [root@3dcpc5 ~]# btrfs check --repair /dev/sdk > enabling repair mode > Checking filesystem on /dev/sdk > UUID: 6a742786-070d-4557-9e67-c73b84967bf5 > checking extents > Fixed 0 roots. > checking free space cache > cache and super generation don't match, space cache will be invalidated This might be there because of the crash earlier, but a cache invalidation should not be a problem. > checking fs roots > reset nbytes for ino 1341670 root 5 > reset nbytes for ino 1341670 root 11406 At least the nbytes error seems to be fixed. > warning line 3653 > checking csums > checking root refs > found 19343374874998 bytes used err is 0 > total csum bytes: 18863243900 > total tree bytes: 27413118976 > total fs tree bytes: 4455694336 > total extent tree bytes: 3077373952 > btree space waste bytes: 2882193883 > file data blocks allocated: 19461564538880 > referenced 20155355832320 The second readonly check partly can't deal with the just invalidated space cache I think (I assume you haven't mounted and/or/ used read-write the filesystem in between), but even if the space cache wouldn't be touched in the --repair check, my experience is that those errors, like in dmesg on my system: [38018.645187] BTRFS info (device sdi): The free space cache file (6258971115520) is invalid. skip it will disappear over time when the filesystem is filled/used. This particular error is from a backup fs where one disk had gone bad. A btrfs replace still worked and just after that, I saw many of those errors, but now after a few weeks they are mostly gone. I did not explicitly unmount or check--repair the fs, I just had to reboot the system for another reason. Your kernel+tools is new enough, you probably want to have a look at the 'Space cache control' options on the wiki: https://btrfs.wiki.kernel.org/index.php/Mount_options before you decide what to do. > root@3dcpc5 ~]# btrfs check /dev/sdk > Checking filesystem on /dev/sdk > UUID: 6a742786-070d-4557-9e67-c73b84967bf5 > checking extents > checking free space cache > block group 53328591454208 has wrong amount of free space > failed to load free space cache for block group 53328591454208 > block group 53329665196032 has wrong amount of free space > failed to load free space cache for block group 53329665196032 > Wanted offset 58836887044096, found 58836887011328 > Wanted offset 58836887044096, found 58836887011328 > cache appears valid but isnt 58836887011328 > Wanted offset 60505481887744, found 60505481805824 > Wanted offset 60505481887744, found 60505481805824 > cache appears valid but isnt 60505481805824 > Wanted bytes 16384, found 81920 for off 60979001966592 > Wanted bytes 1073725440, found 81920 for off 60979001966592 > cache appears valid but isnt 60979001950208 > Wanted offset 61297908056064, found 61297908006912 > Wanted offset 61297908056064, found 61297908006912 > cache appears valid but isnt 61297903271936 > Wanted bytes 32768, found 16384 for off 61711301296128 > Wanted bytes 1066319872, found 16384 for off 61711301296128 > cache appears valid but isnt 61711293874176 > There is no free space entry for 62691824041984-62691824058368 > There is no free space entry for 62691824041984-62692693901312 > cache appears valid but isnt 62691620159488 > There is no free space entry for 63723505205248-63723505221632 > There is no free space entry for 63723505205248-63724559794176 > cache appears valid but isnt 63723486052352 > Wanted bytes 32768, found 16384 for off 64746920902656 > Wanted bytes 914849792, found 16384 for off 64746920902656 > cache appears valid but isnt 64746762010624 > There is no free space entry for 65770368401408-65770368434176 > There is no free space entry for 65770368401408-65771111710720 > cache appears valid but isnt 65770037968896 > Wanted offset 66758954270720, found 66758954221568 > Wanted offset 66758954270720, found 66758954221568 > cache appears valid but isnt 66758954188800 > block group 70204591702016 has wrong amount of free space > failed to load free space cache for block group 70204591702016 > block group 70205665443840 has wrong amount of free space > failed to load free space cache for block group 70205665443840 > block group 70206739185664 has wrong amount of free space > failed to load free space cache for block group 70206739185664 > Wanted offset 70216543715328, found 70216543698944 > Wanted offset 70216543715328, found 70216543698944 > cache appears valid but isnt 70216537079808 > Wanted offset 71025067474944, found 71025067409408 > Wanted offset 71025067474944, found 71025067409408 > cache appears valid but isnt 71025064673280 > Wanted offset 71455641354240, found 71455641337856 > Wanted offset 71455641354240, found 71455641337856 > cache appears valid but isnt 71455635144704 > block group 71662867316736 has wrong amount of free space > failed to load free space cache for block group 71662867316736 > block group 71663941058560 has wrong amount of free space > failed to load free space cache for block group 71663941058560 > There is no free space entry for 72725872967680-72725872984064 > There is no free space entry for 72725872967680-72726945464320 > cache appears valid but isnt 72725871722496 > block group 73207981801472 has wrong amount of free space > failed to load free space cache for block group 73207981801472 > found 19343374940534 bytes used err is -22 > total csum bytes: 18863243900 > total tree bytes: 27413184512 > total fs tree bytes: 4455727104 > total extent tree bytes: 3077406720 > btree space waste bytes: 2882234096 > file data blocks allocated: 19461573357568 > referenced 20155367563264 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
