From 855662c61184b1e6ffaec8057ad3c41418cb6790 Mon Sep 17 00:00:00 2001
From: Kirk McKusick <mckusick@FreeBSD.org>
Date: Mon, 4 Sep 2017 20:19:36 +0000
Subject: [PATCH] The new fsck recovery information to enable it to find backup
 superblocks created in revision 322297 only works on disks with sector sizes
 up to 4K. This update allows the recovery information to be created by newfs
 and used by fsck on disks with sector sizes up to 64K. Note that FFS
 currently limits filesystem to be mounted from disks with up to 8K sectors.
 Expanding this limitation will be the subject of another commit.

Reported by: Peter Holm
Reviewed with: kib
---
 sbin/fsck_ffs/setup.c | 90 +++++++++++++++++++++++++++++++------------
 sbin/newfs/mkfs.c     | 31 ++++++++-------
 sys/ufs/ffs/fs.h      |  2 -
 3 files changed, 83 insertions(+), 40 deletions(-)

diff --git a/sbin/fsck_ffs/setup.c b/sbin/fsck_ffs/setup.c
index f97a3fed0f83..62e27053a2b8 100644
--- a/sbin/fsck_ffs/setup.c
+++ b/sbin/fsck_ffs/setup.c
@@ -36,6 +36,7 @@ static const char sccsid[] = "@(#)setup.c	8.10 (Berkeley) 5/9/95";
 __FBSDID("$FreeBSD$");
 
 #include <sys/param.h>
+#include <sys/disk.h>
 #include <sys/stat.h>
 #define FSTYPENAMES
 #include <sys/disklabel.h>
@@ -465,7 +466,9 @@ sblock_init(void)
 static int
 calcsb(char *dev, int devfd, struct fs *fs)
 {
-	struct fsrecovery fsr;
+	struct fsrecovery *fsr;
+	char *fsrbuf;
+	u_int secsize;
 
 	/*
 	 * We need fragments-per-group and the partition-size.
@@ -475,32 +478,62 @@ calcsb(char *dev, int devfd, struct fs *fs)
 	 * overwritten by a boot block, we fail. But usually they are
 	 * there and we can use them.
 	 */
-	if (blread(devfd, (char *)&fsr,
-	    (SBLOCK_UFS2 - sizeof(fsr)) / dev_bsize, sizeof(fsr)) ||
-	    fsr.fsr_magic != FS_UFS2_MAGIC)
+	if (ioctl(devfd, DIOCGSECTORSIZE, &secsize) == -1)
+		return (0);
+	fsrbuf = Malloc(secsize);
+	if (fsrbuf == NULL)
+		errx(EEXIT, "calcsb: cannot allocate recovery buffer");
+	if (blread(devfd, fsrbuf,
+	    (SBLOCK_UFS2 - secsize) / dev_bsize, secsize) != 0)
+		return (0);
+	fsr = (struct fsrecovery *)&fsrbuf[secsize - sizeof *fsr];
+	if (fsr->fsr_magic != FS_UFS2_MAGIC)
 		return (0);
 	memset(fs, 0, sizeof(struct fs));
-	fs->fs_fpg = fsr.fsr_fpg;
-	fs->fs_fsbtodb = fsr.fsr_fsbtodb;
-	fs->fs_sblkno = fsr.fsr_sblkno;
-	fs->fs_magic = fsr.fsr_magic;
-	fs->fs_ncg = fsr.fsr_ncg;
+	fs->fs_fpg = fsr->fsr_fpg;
+	fs->fs_fsbtodb = fsr->fsr_fsbtodb;
+	fs->fs_sblkno = fsr->fsr_sblkno;
+	fs->fs_magic = fsr->fsr_magic;
+	fs->fs_ncg = fsr->fsr_ncg;
+	free(fsrbuf);
 	return (1);
 }
 
 /*
  * Check to see if recovery information exists.
+ * Return 1 if it exists or cannot be created.
+ * Return 0 if it does not exist and can be created.
  */
 static int
 chkrecovery(int devfd)
 {
-	struct fsrecovery fsr;
+	struct fsrecovery *fsr;
+	char *fsrbuf;
+	u_int secsize;
 
-	if (blread(devfd, (char *)&fsr,
-	    (SBLOCK_UFS2 - sizeof(fsr)) / dev_bsize, sizeof(fsr)) ||
-	    fsr.fsr_magic != FS_UFS2_MAGIC)
-		return (0);
-	return (1);
+	/*
+	 * Could not determine if backup material exists, so do not
+	 * offer to create it.
+	 */
+	if (ioctl(devfd, DIOCGSECTORSIZE, &secsize) == -1 ||
+	    (fsrbuf = Malloc(secsize)) == NULL ||
+	    blread(devfd, fsrbuf, (SBLOCK_UFS2 - secsize) / dev_bsize,
+	      secsize) != 0)
+		return (1);
+	/*
+	 * Recovery material has already been created, so do not
+	 * need to create it again.
+	 */
+	fsr = (struct fsrecovery *)&fsrbuf[secsize - sizeof *fsr];
+	if (fsr->fsr_magic == FS_UFS2_MAGIC) {
+		free(fsrbuf);
+		return (1);
+	}
+	/*
+	 * Recovery material has not been created and can be if desired.
+	 */
+	free(fsrbuf);
+	return (0);
 }
 
 /*
@@ -511,17 +544,24 @@ chkrecovery(int devfd)
 static void
 saverecovery(int readfd, int writefd)
 {
-	struct fsrecovery fsr;
+	struct fsrecovery *fsr;
+	char *fsrbuf;
+	u_int secsize;
 
 	if (sblock.fs_magic != FS_UFS2_MAGIC ||
-	    blread(readfd, (char *)&fsr,
-	    (SBLOCK_UFS2 - sizeof(fsr)) / dev_bsize, sizeof(fsr)))
+	    ioctl(readfd, DIOCGSECTORSIZE, &secsize) == -1 ||
+	    (fsrbuf = Malloc(secsize)) == NULL ||
+	    blread(readfd, fsrbuf, (SBLOCK_UFS2 - secsize) / dev_bsize,
+	      secsize) != 0) {
+		printf("RECOVERY DATA COULD NOT BE CREATED\n");
 		return;
-	fsr.fsr_magic = sblock.fs_magic;
-	fsr.fsr_fpg = sblock.fs_fpg;
-	fsr.fsr_fsbtodb = sblock.fs_fsbtodb;
-	fsr.fsr_sblkno = sblock.fs_sblkno;
-	fsr.fsr_ncg = sblock.fs_ncg;
-	blwrite(writefd, (char *)&fsr, (SBLOCK_UFS2 - sizeof(fsr)) / dev_bsize,
-	    sizeof(fsr));
+	}
+	fsr = (struct fsrecovery *)&fsrbuf[secsize - sizeof *fsr];
+	fsr->fsr_magic = sblock.fs_magic;
+	fsr->fsr_fpg = sblock.fs_fpg;
+	fsr->fsr_fsbtodb = sblock.fs_fsbtodb;
+	fsr->fsr_sblkno = sblock.fs_sblkno;
+	fsr->fsr_ncg = sblock.fs_ncg;
+	blwrite(writefd, fsrbuf, (SBLOCK_UFS2 - secsize) / secsize, secsize);
+	free(fsrbuf);
 }
diff --git a/sbin/newfs/mkfs.c b/sbin/newfs/mkfs.c
index 3cbfad8c49d7..dbfab4536bd6 100644
--- a/sbin/newfs/mkfs.c
+++ b/sbin/newfs/mkfs.c
@@ -121,7 +121,8 @@ mkfs(struct partition *pp, char *fsys)
 	ino_t maxinum;
 	int minfragsperinode;	/* minimum ratio of frags to inodes */
 	char tmpbuf[100];	/* XXX this will break in about 2,500 years */
-	struct fsrecovery fsr;
+	struct fsrecovery *fsr;
+	char *fsrbuf;
 	union {
 		struct fs fdummy;
 		char cdummy[SBLOCKSIZE];
@@ -442,6 +443,8 @@ restart:
 	sblock.fs_sbsize = fragroundup(&sblock, sizeof(struct fs));
 	if (sblock.fs_sbsize > SBLOCKSIZE)
 		sblock.fs_sbsize = SBLOCKSIZE;
+	if (sblock.fs_sbsize < realsectorsize)
+		sblock.fs_sbsize = realsectorsize;
 	sblock.fs_minfree = minfree;
 	if (metaspace > 0 && metaspace < sblock.fs_fpg / 2)
 		sblock.fs_metaspace = blknum(&sblock, metaspace);
@@ -514,7 +517,7 @@ restart:
 	/*
 	 * Wipe out old UFS1 superblock(s) if necessary.
 	 */
-	if (!Nflag && Oflag != 1) {
+	if (!Nflag && Oflag != 1 && realsectorsize <= SBLOCK_UFS1) {
 		i = bread(&disk, part_ofs + SBLOCK_UFS1 / disk.d_bsize, chdummy, SBLOCKSIZE);
 		if (i == -1)
 			err(1, "can't read old UFS1 superblock: %s", disk.d_error);
@@ -623,18 +626,20 @@ restart:
 	 * The recovery information only works for UFS2 filesystems.
 	 */
 	if (sblock.fs_magic == FS_UFS2_MAGIC) {
-		i = bread(&disk,
-		    part_ofs + (SBLOCK_UFS2 - sizeof(fsr)) / disk.d_bsize,
-		    (char *)&fsr, sizeof(fsr));
-		if (i == -1)
+		if ((fsrbuf = malloc(realsectorsize)) == NULL || bread(&disk,
+		    part_ofs + (SBLOCK_UFS2 - realsectorsize) / disk.d_bsize,
+		    fsrbuf, realsectorsize) == -1)
 			err(1, "can't read recovery area: %s", disk.d_error);
-		fsr.fsr_magic = sblock.fs_magic;
-		fsr.fsr_fpg = sblock.fs_fpg;
-		fsr.fsr_fsbtodb = sblock.fs_fsbtodb;
-		fsr.fsr_sblkno = sblock.fs_sblkno;
-		fsr.fsr_ncg = sblock.fs_ncg;
-		wtfs((SBLOCK_UFS2 - sizeof(fsr)) / disk.d_bsize, sizeof(fsr),
-		    (char *)&fsr);
+		fsr =
+		    (struct fsrecovery *)&fsrbuf[realsectorsize - sizeof *fsr];
+		fsr->fsr_magic = sblock.fs_magic;
+		fsr->fsr_fpg = sblock.fs_fpg;
+		fsr->fsr_fsbtodb = sblock.fs_fsbtodb;
+		fsr->fsr_sblkno = sblock.fs_sblkno;
+		fsr->fsr_ncg = sblock.fs_ncg;
+		wtfs((SBLOCK_UFS2 - realsectorsize) / disk.d_bsize,
+		    realsectorsize, fsrbuf);
+		free(fsrbuf);
 	}
 	/*
 	 * Update information about this partition in pack
diff --git a/sys/ufs/ffs/fs.h b/sys/ufs/ffs/fs.h
index 8de35ffbbd74..81fbeda84c1e 100644
--- a/sys/ufs/ffs/fs.h
+++ b/sys/ufs/ffs/fs.h
@@ -237,9 +237,7 @@ struct fsck_cmd {
  * A recovery structure placed at the end of the boot block area by newfs
  * that can be used by fsck to search for alternate superblocks.
  */
-#define RESID	(4096 - 20)	/* disk sector size minus recovery area size */
 struct fsrecovery {
-	char	block[RESID];	/* unused part of sector */
 	int32_t	fsr_magic;	/* magic number */
 	int32_t	fsr_fsbtodb;	/* fsbtodb and dbtofsb shift constant */
 	int32_t	fsr_sblkno;	/* offset of super-block in filesys */