Re: [git pull] first batch of ufs fixes

[Richard Narron <comet.berkeley@gmail.com>]

On Fri, 9 Jun 2017, Al Viro wrote:

> 	That's just the obvious backport fodder; I'm pretty sure that there
> will be more - definitely so wrt performance and quite possibly correctness
> as well.

These fixes improve the ufs code and they are a good start.

Here are a couple of bugs that still remain:

1) Just after creating a new filesystem on FreeBSD 11.0, the FreeBSD df 
is different from the Linux 4.12.0-rc4 with the ufs fixes.  The available 
count on Linux is is 16k higher than on FreeBSD:

FreeBSD 11.0:
   #df /diske
   Filesystem   1K-blocks Used    Avail Capacity  Mounted on
   /dev/ada0s3e  14217008    8 13079640     0%    /diske

Linux 4.12-0-rc4 with ufs fixes:
   #df /fbsd23
   Filesystem     1K-blocks  Used Available Use% Mounted on
   /dev/sda23      14217008     8  13079656   1% /fbsd23

2) After creating a new filesystem on FreeBSD, then on Linux copying 
a larger than 2GB file and creating a directory, the fsck back on FreeBSD 
looks ok.

But after going back to Linux and removing the large file and removing the 
directory, the fsck on FreeBSD looks not so good:

Linux:
   #cp /fbsd/tmp/usr-local.tar /fbsd23
   #mkdir                      /fbsd23/a

FreeBSD:
   #fsck -f /dev/ada0s3e
   ** /dev/ada0s3e
   ** Last Mounted on /diske
   ** Phase 1 - Check Blocks and Sizes
   ** Phase 2 - Check Pathnames
   ** Phase 3 - Check Connectivity
   ** Phase 4 - Check Reference Counts
   ** Phase 5 - Check Cyl groups
   4 files, 636219 used, 2918033 free (25 frags, 364751 blocks, 0.0%
   fragmentation)
   ***** FILE SYSTEM IS CLEAN *****

Linux:
   #cd /fbsd23
   rm    usr-local.tar
   rmdir a

FreeBSD:
   #fsck -n -f /dev/ada0s3e
   ** /dev/ada0s3e (NO WRITE)
   ** Last Mounted on /diske
   ** Phase 1 - Check Blocks and Sizes
   ** Phase 2 - Check Pathnames
   ** Phase 3 - Check Connectivity
   UNREF DIR  I=5  OWNER=root MODE=40755
   SIZE=512 MTIME=Jun 10 01:51 2017
   RECONNECT? no

   ** Phase 4 - Check Reference Counts
   LINK COUNT DIR I=2  OWNER=root MODE=40755
   SIZE=512 MTIME=Jun 10 02:04 2017  COUNT 3 SHOULD BE 4
   ADJUST? no

   UNREF FILE  I=4  OWNER=root MODE=100644
   SIZE=2605231616 MTIME=Jun 10 01:47 2017
   RECONNECT? no

   CLEAR? no

   LINK COUNT DIR I=5  OWNER=root MODE=40755
   SIZE=512 MTIME=Jun 10 01:51 2017  COUNT 2 SHOULD BE 1
   ADJUST? no

   ** Phase 5 - Check Cyl groups
   FREE BLK COUNT(S) WRONG IN SUPERBLK
   SALVAGE? no

   SUMMARY INFORMATION BAD
   SALVAGE? no

   BLK(S) MISSING IN BIT MAPS
   SALVAGE? no

   4 files, 636219 used, 3554250 free (26 frags, 444278 blocks, 0.0%
   fragmentation)