Author: mckusick
Date: Thu Feb  8 23:06:58 2018
New Revision: 329051
URL: https://svnweb.freebsd.org/changeset/base/329051

Log:
  The goal of this change is to prevent accidental foot shooting by
  folks running filesystems created on check-hash enabled kernels
  (which I will call "new") on a non-check-hash enabled kernels (which
  I will call "old). The idea here is to detect when a filesystem is
  run on an old kernel and flag the filesystem so that when it gets
  moved back to a new kernel, it will not start getting a slew of
  check-hash errors.
  
  Back when the UFS version 2 filesystem was created, it added a file
  flag FS_INDEXDIRS that was to be set on any filesystem that kept
  some sort of on-disk indexing for directories. The idea was precisely
  to solve the issue we have today. Specifically that a newer kernel
  that supported indexing would be able to tell that the filesystem
  had been run on an older non-indexing kernel and that the indexes
  should not be used until they had been rebuilt. Since we have never
  implemented on-disk directory indicies, the FS_INDEXDIRS flag is
  cleared every time any UFS version 2 filesystem ever created is
  mounted for writing.
  
  This commit repurposes the FS_INDEXDIRS flag as the FS_METACKHASH
  flag. Thus, the FS_METACKHASH is definitively known to have always
  been cleared. The FS_INDEXDIRS flag has been moved to a new block
  of flags that will always be cleared starting with this commit
  (until they get used to implement some future feature which needs
  to detect that the filesystem was mounted on a kernel that predates
  the new feature).
  
  If a filesystem with check-hashes enabled is mounted on an old
  kernel the FS_METACKHASH flag is cleared. When that filesystem is
  mounted on a new kernel it will see that the FS_METACKHASH has been
  cleared and clears all of the fs_metackhash flags. To get them
  re-enabled the user must run fsck (in interactive mode without the
  -y flag) which will ask for each supported check hash whether it
  should be rebuilt and enabled. When fsck is run in its default preen
  mode, it will just ignore the check hashes so they will remain
  disabled.
  
  The kernel has always disabled any check hash functions that it
  does not support, so as more types of check hashes are added, we
  will get a non-surprising result. Specifically if filesystems get
  moved to kernels supporting fewer of the check hashes, those that
  are not supported will be disabled. If the filesystem is moved back
  to a kernel with more of the check-hashes available and fsck is run
  interactively to rebuild them, then their checking will resume.
  Otherwise just the smaller subset will be checked.
  
  A side effect of this commit is that filesystems running with
  cylinder-group check hashes will stop having them checked until
  fsck is run to re-enable them (since none of them currently have
  the FS_METACKHASH flag set). So, if you want check hashes enabled
  on your filesystems after booting a kernel with these changes, you
  need to run fsck to enable them. Any newly created filesystems will
  have check hashes enabled. If in doubt as to whether you have check
  hashes emabled, run dumpfs and look at the list of enabled flags
  at the end of the superblock details.

Modified:
  head/sbin/dumpfs/dumpfs.c
  head/sbin/fsck_ffs/pass5.c
  head/sbin/newfs/mkfs.c
  head/sys/ufs/ffs/ffs_vfsops.c
  head/sys/ufs/ffs/fs.h

Modified: head/sbin/dumpfs/dumpfs.c
==============================================================================
--- head/sbin/dumpfs/dumpfs.c   Thu Feb  8 22:59:51 2018        (r329050)
+++ head/sbin/dumpfs/dumpfs.c   Thu Feb  8 23:06:58 2018        (r329051)
@@ -257,9 +257,9 @@ dumpfs(const char *name)
        if (fsflags & FS_DOSOFTDEP)
                printf("soft-updates%s ", (fsflags & FS_SUJ) ? "+journal" : "");
        if (fsflags & FS_NEEDSFSCK)
-               printf("needs fsck run ");
+               printf("needs-fsck-run ");
        if (fsflags & FS_INDEXDIRS)
-               printf("indexed directories ");
+               printf("indexed-directories ");
        if (fsflags & FS_ACLS)
                printf("acls ");
        if (fsflags & FS_MULTILABEL)
@@ -267,31 +267,33 @@ dumpfs(const char *name)
        if (fsflags & FS_GJOURNAL)
                printf("gjournal ");
        if (fsflags & FS_FLAGS_UPDATED)
-               printf("fs_flags expanded ");
+               printf("fs_flags-expanded ");
        if (fsflags & FS_NFS4ACLS)
                printf("nfsv4acls ");
        if (fsflags & FS_TRIM)
                printf("trim ");
-       fsflags &= ~(FS_UNCLEAN | FS_DOSOFTDEP | FS_NEEDSFSCK | FS_INDEXDIRS |
+       fsflags &= ~(FS_UNCLEAN | FS_DOSOFTDEP | FS_NEEDSFSCK | FS_METACKHASH |
                     FS_ACLS | FS_MULTILABEL | FS_GJOURNAL | FS_FLAGS_UPDATED |
-                    FS_NFS4ACLS | FS_SUJ | FS_TRIM);
+                    FS_NFS4ACLS | FS_SUJ | FS_TRIM | FS_INDEXDIRS);
        if (fsflags != 0)
-               printf("unknown flags (%#x)", fsflags);
+               printf("unknown-flags (%#x)", fsflags);
        putchar('\n');
-       printf("check hashes\t");
-       fsflags = afs.fs_metackhash;
-       if (fsflags == 0)
-               printf("none");
-       if (fsflags & CK_SUPERBLOCK)
-               printf("superblock ");
-       if (fsflags & CK_CYLGRP)
-               printf("cylinder-groups ");
-       if (fsflags & CK_INODE)
-               printf("inodes ");
-       if (fsflags & CK_INDIR)
-               printf("indirect-blocks ");
-       if (fsflags & CK_DIR)
-               printf("directories ");
+       if (afs.fs_flags & FS_METACKHASH) {
+               printf("check hashes\t");
+               fsflags = afs.fs_metackhash;
+               if (fsflags == 0)
+                       printf("none");
+               if (fsflags & CK_SUPERBLOCK)
+                       printf("superblock ");
+               if (fsflags & CK_CYLGRP)
+                       printf("cylinder-groups ");
+               if (fsflags & CK_INODE)
+                       printf("inodes ");
+               if (fsflags & CK_INDIR)
+                       printf("indirect-blocks ");
+               if (fsflags & CK_DIR)
+                       printf("directories ");
+       }
        fsflags &= ~(CK_SUPERBLOCK | CK_CYLGRP | CK_INODE | CK_INDIR | CK_DIR);
        if (fsflags != 0)
                printf("unknown flags (%#x)", fsflags);

Modified: head/sbin/fsck_ffs/pass5.c
==============================================================================
--- head/sbin/fsck_ffs/pass5.c  Thu Feb  8 22:59:51 2018        (r329050)
+++ head/sbin/fsck_ffs/pass5.c  Thu Feb  8 23:06:58 2018        (r329051)
@@ -37,7 +37,6 @@ static const char sccsid[] = "@(#)pass5.c     8.9 (Berkele
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
-#define        IN_RTLD                 /* So we pickup the P_OSREL defines */
 #include <sys/param.h>
 #include <sys/sysctl.h>
 
@@ -63,7 +62,7 @@ pass5(void)
        int inomapsize, blkmapsize;
        struct fs *fs = &sblock;
        ufs2_daddr_t d, dbase, dmax, start;
-       int rewritecg = 0, cgckadd = 0;
+       int rewritecg = 0;
        struct csum *cs;
        struct csum_total cstotal;
        struct inodesc idesc[3];
@@ -74,13 +73,10 @@ pass5(void)
        inoinfo(UFS_WINO)->ino_state = USTATE;
        memset(newcg, 0, (size_t)fs->fs_cgsize);
        newcg->cg_niblk = fs->fs_ipg;
-       if (preen == 0 && yflag == 0 && fs->fs_magic == FS_UFS2_MAGIC &&
-           fswritefd != -1 && (fs->fs_metackhash & CK_CYLGRP) == 0 &&
-           getosreldate() >= P_OSREL_CK_CYLGRP &&
-           reply("ADD CYLINDER GROUP CHECKSUM PROTECTION") != 0) {
+       /* check to see if we are to add a cylinder group check hash */
+       if ((ckhashadd & CK_CYLGRP) != 0) {
                fs->fs_metackhash |= CK_CYLGRP;
                rewritecg = 1;
-               cgckadd = 1;
                sbdirty();
        }
        if (cvtlevel >= 3) {
@@ -178,14 +174,20 @@ pass5(void)
                cg = cgbp->b_un.b_cg;
                if (!cg_chkmagic(cg))
                        pfatal("CG %d: BAD MAGIC NUMBER\n", c);
-               if ((fs->fs_metackhash & CK_CYLGRP) != 0 && cgckadd == 0) {
+               /*
+                * If we have a cylinder group check hash and are not adding
+                * it for the first time, verify that it is good.
+                */
+               if ((fs->fs_metackhash & CK_CYLGRP) != 0 &&
+                   (ckhashadd & CK_CYLGRP) == 0) {
                        uint32_t ckhash, thishash;
 
                        ckhash = cg->cg_ckhash;
                        cg->cg_ckhash = 0;
                        thishash = calculate_crc32c(~0L, cg, fs->fs_cgsize);
                        if (ckhash != thishash)
-                               pwarn("CG %d: BAD CHECKSUM %#x vs %#x", c, 
ckhash, thishash);
+                               pwarn("CG %d: BAD CHECK-HASH %#x vs %#x",
+                                   c, ckhash, thishash);
                        cg->cg_ckhash = ckhash;
                }
                newcg->cg_time = cg->cg_time;

Modified: head/sbin/newfs/mkfs.c
==============================================================================
--- head/sbin/newfs/mkfs.c      Thu Feb  8 22:59:51 2018        (r329050)
+++ head/sbin/newfs/mkfs.c      Thu Feb  8 23:06:58 2018        (r329051)
@@ -489,9 +489,15 @@ restart:
        }
        /*
         * Set flags for metadata that is being check-hashed.
+        *
+        * Metadata check hashes are not supported in the UFS version 1
+        * filesystem to keep it as small and simple as possible.
         */
-       if (Oflag > 1 && getosreldate() >= P_OSREL_CK_CYLGRP)
-               sblock.fs_metackhash = CK_CYLGRP;
+       if (Oflag > 1) {
+               sblock.fs_flags |= FS_METACKHASH;
+               if (getosreldate() >= P_OSREL_CK_CYLGRP)
+                       sblock.fs_metackhash = CK_CYLGRP;
+       }
 
        /*
         * Dump out summary information about file system.

Modified: head/sys/ufs/ffs/ffs_vfsops.c
==============================================================================
--- head/sys/ufs/ffs/ffs_vfsops.c       Thu Feb  8 22:59:51 2018        
(r329050)
+++ head/sys/ufs/ffs/ffs_vfsops.c       Thu Feb  8 23:06:58 2018        
(r329051)
@@ -809,10 +809,12 @@ ffs_mountfs(devvp, mp, td)
        if ((error = ffs_sbget(devvp, &fs, -1, M_UFSMNT, ffs_use_bread)) != 0)
                goto out;
        fs->fs_fmod = 0;
-       /* none of these types of check-hashes are maintained */
+       /* if we ran on a kernel without metadata check hashes, disable them */
+       if ((fs->fs_flags & FS_METACKHASH) == 0)
+               fs->fs_metackhash = 0;
+       /* none of these types of check-hashes are maintained by this kernel */
        fs->fs_metackhash &= ~(CK_SUPERBLOCK | CK_INODE | CK_INDIR | CK_DIR);
-       /* no support for directory indices or any other undefined flags */
-       fs->fs_flags &= ~FS_INDEXDIRS;
+       /* no support for any undefined flags */
        fs->fs_flags &= FS_SUPPORTED;
        fs->fs_flags &= ~FS_UNCLEAN;
        if (fs->fs_clean == 0) {

Modified: head/sys/ufs/ffs/fs.h
==============================================================================
--- head/sys/ufs/ffs/fs.h       Thu Feb  8 22:59:51 2018        (r329050)
+++ head/sys/ufs/ffs/fs.h       Thu Feb  8 23:06:58 2018        (r329051)
@@ -433,18 +433,31 @@ CTASSERT(sizeof(struct fs) == 1376);
  * labels into extended attributes on the file system rather than maintain
  * a single mount label for all objects.
  */
-#define        FS_UNCLEAN      0x0001  /* filesystem not clean at mount */
-#define        FS_DOSOFTDEP    0x0002  /* filesystem using soft dependencies */
-#define        FS_NEEDSFSCK    0x0004  /* filesystem needs sync fsck before 
mount */
-#define        FS_SUJ          0x0008  /* Filesystem using softupdate journal 
*/
-#define        FS_ACLS         0x0010  /* file system has POSIX.1e ACLs 
enabled */
-#define        FS_MULTILABEL   0x0020  /* file system is MAC multi-label */
-#define        FS_GJOURNAL     0x0040  /* gjournaled file system */
-#define        FS_FLAGS_UPDATED 0x0080 /* flags have been moved to new 
location */
-#define        FS_NFS4ACLS     0x0100  /* file system has NFSv4 ACLs enabled */
-#define        FS_INDEXDIRS    0x0200  /* kernel supports indexed directories 
*/
-#define        FS_TRIM         0x0400  /* issue BIO_DELETE for deleted blocks 
*/
-#define        FS_SUPPORTED    0xFFFF  /* supported flags, others cleared at 
mount */
+#define        FS_UNCLEAN      0x00000001 /* filesystem not clean at mount */
+#define        FS_DOSOFTDEP    0x00000002 /* filesystem using soft 
dependencies */
+#define        FS_NEEDSFSCK    0x00000004 /* filesystem needs sync fsck before 
mount */
+#define        FS_SUJ          0x00000008 /* Filesystem using softupdate 
journal */
+#define        FS_ACLS         0x00000010 /* file system has POSIX.1e ACLs 
enabled */
+#define        FS_MULTILABEL   0x00000020 /* file system is MAC multi-label */
+#define        FS_GJOURNAL     0x00000040 /* gjournaled file system */
+#define        FS_FLAGS_UPDATED 0x0000080 /* flags have been moved to new 
location */
+#define        FS_NFS4ACLS     0x00000100 /* file system has NFSv4 ACLs 
enabled */
+#define        FS_METACKHASH   0x00000200 /* kernel supports metadata check 
hashes */
+#define        FS_TRIM         0x00000400 /* issue BIO_DELETE for deleted 
blocks */
+#define        FS_SUPPORTED    0x00FFFFFF /* supported flags, others cleared 
at mount*/
+/*
+ * Things that we may someday support, but currently do not.
+ * These flags are all cleared so we know if we ran on a kernel
+ * that does not support them.
+ */
+#define        FS_INDEXDIRS    0x01000000 /* kernel supports indexed 
directories */
+#define        FS_VARBLKSIZE   0x02000000 /* kernel supports variable block 
sizes */
+#define        FS_COOLOPT1     0x04000000 /* kernel supports cool option 1 */
+#define        FS_COOLOPT2     0x08000000 /* kernel supports cool option 2 */
+#define        FS_COOLOPT3     0x10000000 /* kernel supports cool option 3 */
+#define        FS_COOLOPT4     0x20000000 /* kernel supports cool option 4 */
+#define        FS_COOLOPT5     0x40000000 /* kernel supports cool option 5 */
+#define        FS_COOLOPT6     0x80000000 /* kernel supports cool option 6 */
 
 /*
  * The fs_metackhash field indicates the types of metadata check-hash
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