On Wed, 14 Jun 2017, Al Viro wrote:
...
AFAICS, a conservative approach would be
        * reject UFS_42POSTBLFMT for 44bsd ones - it's almost certainly
*not* one.
        * check if fs_maxbsize is equal to frag size; treat that as
"counts are read from new location and stored both to old and new".
44bsd fs_maxbsize != block size => not converted, just use old locations
for everything.  UFS2 => use new locations for everything, don't bother
with old ones.  IOW, something like this (WARNING: completely untested,
might screw your filesystem) might do.

NOTE: all I have is your image *after* it had counters buggered; I don't
know the exact sequence of operations that fucked it in your case.  One
way to trigger it is to mount/umount on OpenBSD, then mount/modify/umount
on Linux, then mount/umount on OpenBSD, then fsck on OpenBSD.  This patch
apparently fixes that, but your reproducer might be something different.

Signed-off-by: Al Viro <[email protected]>
---
diff --git a/fs/ufs/super.c b/fs/ufs/super.c
index d9aa2627c9df..eca838a8b43e 100644
--- a/fs/ufs/super.c
+++ b/fs/ufs/super.c
@@ -480,7 +480,7 @@ static void ufs_setup_cstotal(struct super_block *sb)
        usb3 = ubh_get_usb_third(uspi);

        if ((mtype == UFS_MOUNT_UFSTYPE_44BSD &&
-            (usb1->fs_flags & UFS_FLAGS_UPDATED)) ||
+            (usb2->fs_un.fs_u2.fs_maxbsize == usb1->fs_bsize)) ||
            mtype == UFS_MOUNT_UFSTYPE_UFS2) {
                /*we have statistic in different place, then usual*/
                uspi->cs_total.cs_ndir = fs64_to_cpu(sb, 
usb2->fs_un.fs_u2.cs_ndir);
@@ -596,9 +596,7 @@ static void ufs_put_cstotal(struct super_block *sb)
        usb2 = ubh_get_usb_second(uspi);
        usb3 = ubh_get_usb_third(uspi);

-       if ((mtype == UFS_MOUNT_UFSTYPE_44BSD &&
-            (usb1->fs_flags & UFS_FLAGS_UPDATED)) ||
-           mtype == UFS_MOUNT_UFSTYPE_UFS2) {
+       if (mtype == UFS_MOUNT_UFSTYPE_UFS2) {
                /*we have statistic in different place, then usual*/
                usb2->fs_un.fs_u2.cs_ndir =
                        cpu_to_fs64(sb, uspi->cs_total.cs_ndir);
@@ -608,16 +606,26 @@ static void ufs_put_cstotal(struct super_block *sb)
                        cpu_to_fs64(sb, uspi->cs_total.cs_nifree);
                usb3->fs_un1.fs_u2.cs_nffree =
                        cpu_to_fs64(sb, uspi->cs_total.cs_nffree);
-       } else {
-               usb1->fs_cstotal.cs_ndir =
-                       cpu_to_fs32(sb, uspi->cs_total.cs_ndir);
-               usb1->fs_cstotal.cs_nbfree =
-                       cpu_to_fs32(sb, uspi->cs_total.cs_nbfree);
-               usb1->fs_cstotal.cs_nifree =
-                       cpu_to_fs32(sb, uspi->cs_total.cs_nifree);
-               usb1->fs_cstotal.cs_nffree =
-                       cpu_to_fs32(sb, uspi->cs_total.cs_nffree);
+               goto out;
        }
+
+       if (mtype == UFS_MOUNT_UFSTYPE_44BSD &&
+            (usb2->fs_un.fs_u2.fs_maxbsize == usb1->fs_bsize)) {
+               /* store stats in both old and new places */
+               usb2->fs_un.fs_u2.cs_ndir =
+                       cpu_to_fs64(sb, uspi->cs_total.cs_ndir);
+               usb2->fs_un.fs_u2.cs_nbfree =
+                       cpu_to_fs64(sb, uspi->cs_total.cs_nbfree);
+               usb3->fs_un1.fs_u2.cs_nifree =
+                       cpu_to_fs64(sb, uspi->cs_total.cs_nifree);
+               usb3->fs_un1.fs_u2.cs_nffree =
+                       cpu_to_fs64(sb, uspi->cs_total.cs_nffree);
+       }
+       usb1->fs_cstotal.cs_ndir = cpu_to_fs32(sb, uspi->cs_total.cs_ndir);
+       usb1->fs_cstotal.cs_nbfree = cpu_to_fs32(sb, uspi->cs_total.cs_nbfree);
+       usb1->fs_cstotal.cs_nifree = cpu_to_fs32(sb, uspi->cs_total.cs_nifree);
+       usb1->fs_cstotal.cs_nffree = cpu_to_fs32(sb, uspi->cs_total.cs_nffree);
+out:
        ubh_mark_buffer_dirty(USPI_UBH(uspi));
        ufs_print_super_stuff(sb, usb1, usb2, usb3);
        UFSD("EXIT\n");
@@ -997,6 +1005,13 @@ static int ufs_fill_super(struct super_block *sb, void 
*data, int silent)
                flags |=  UFS_ST_SUN;
        }

+       if ((flags & UFS_ST_MASK) == UFS_ST_44BSD &&
+           uspi->s_postblformat == UFS_42POSTBLFMT) {
+               if (!silent)
+                       pr_err("this is not a 44bsd filesystem");
+               goto failed;
+       }
+
        /*
         * Check ufs magic number
         */


Al this patch looks good to me (so far). I tested all 6 combinations of ufs1 and ufs2 in FreeBSD 11.0, OpenBSD 6.1 and NetBSD 7.1

For each combination, I do 5 steps:

  1) BSD: Make a ufs filesystem
     dd if=/dev/zero to the BSD subpartition
     make (newfs) a ufs (1 or 2) filesystem on the BSD subpartiton

  2) Linux: Create a subdirectory and make a large file
     mkdir a
     dd if=/dev/zero bs=1M count=3072

  3) BSD: Check a ufs filesystem
     fsck -f

  4) Linux: Remove the large file and the subdirectory
     rm
     rmdir

  5) BSD; check a ufs filesystem
     fsck -f

Tested-By: Richard Narron <[email protected]>

Reply via email to