[PATCH] xfs_db: exit on invalid magic number

[Eric Sandeen]

On Jan 30, 2009, at 2:47 AM, Christoph Hellwig <hch at infradead.org>  
wrote:

> Fail gracefully and with a useful error message when we detect an
> invalid superblock magic in xfs_db.  Add a new -F flag to continue
> when seeing the invalid magic number - that way xfs_check and
> xfs_metadump can be used on a filesystem that has a corrupted primary
> superblock.
>
>
> Signed-off-by: Christoph Hellwig <hch at lst.de>

Seems good to me, thanks.

-Eric
>
> Index: xfsprogs-dev/db/init.c
> ===================================================================
> --- xfsprogs-dev.orig/db/init.c    2009-01-30 06:42:25.000000000 +0000
> +++ xfsprogs-dev/db/init.c    2009-01-30 06:47:34.000000000 +0000
> @@ -33,6 +33,7 @@
> int        blkbb;
> int        exitcode;
> int        expert_mode;
> +int        force;
> xfs_mount_t    xmount;
> xfs_mount_t    *mp;
> libxfs_init_t    x;
> @@ -42,8 +43,8 @@
> usage(void)
> {
>    fprintf(stderr, _(
> -        "Usage: %s [-frxV] [-p prog] [-l logdev] [-c cmd]... device 
> \n"),
> -        progname);
> +        "Usage: %s [-fFrxV] [-p prog] [-l logdev] [-c cmd]... device 
> \n"
> +        ), progname);
>    exit(1);
> }
>
> @@ -57,7 +58,7 @@
>    int        c;
>
>    progname = basename(argv[0]);
> -    while ((c = getopt(argc, argv, "c:fip:rxVl:")) != EOF) {
> +    while ((c = getopt(argc, argv, "c:fFip:rxVl:")) != EOF) {
>        switch (c) {
>        case 'c':
>            cmdline = xrealloc(cmdline, (ncmdline+1)*sizeof(char*));
> @@ -66,6 +67,9 @@
>        case 'f':
>            x.disfile = 1;
>            break;
> +        case 'F':
> +            force = 1;
> +            break;
>        case 'i':
>            x.isreadonly = (LIBXFS_ISREADONLY|LIBXFS_ISINACTIVE);
>            break;
> @@ -118,8 +122,10 @@
>
>    sbp = &xmount.m_sb;
>    if (sbp->sb_magicnum != XFS_SB_MAGIC) {
> -        fprintf(stderr, _("%s: unexpected XFS SB magic number 0x%08x 
> \n"),
> -            progname, sbp->sb_magicnum);
> +        fprintf(stderr, _("%s: %s is not a valid XFS filesystem  
> (unexpected SB magic number 0x%08x)\n"),
> +            progname, fsdevice, sbp->sb_magicnum);
> +        if (!force)
> +            exit(EXIT_FAILURE);
>    }
>
>    mp = libxfs_mount(&xmount, sbp, x.ddev, x.logdev, x.rtdev,
> Index: xfsprogs-dev/db/xfs_check.sh
> ===================================================================
> --- xfsprogs-dev.orig/db/xfs_check.sh    2009-01-30  
> 06:47:56.000000000 +0000
> +++ xfsprogs-dev/db/xfs_check.sh    2009-01-30 06:48:06.000000000  
> +0000
> @@ -26,7 +26,7 @@
> set -- extra $@
> shift $OPTIND
> case $# in
> -    1)    xfs_db$DBOPTS -i -p xfs_check -c "check$OPTS" $1
> +    1)    xfs_db$DBOPTS -F -i -p xfs_check -c "check$OPTS" $1
>        status=$?
>        ;;
>    *)    echo $USAGE 1>&2
> Index: xfsprogs-dev/db/xfs_check64.sh
> ===================================================================
> --- xfsprogs-dev.orig/db/xfs_check64.sh    2009-01-30  
> 06:47:56.000000000 +0000
> +++ xfsprogs-dev/db/xfs_check64.sh    2009-01-30 06:48:11.000000000  
> +0000
> @@ -26,7 +26,7 @@
> set -- extra $@
> shift $OPTIND
> case $# in
> -    1)    xfs_db64$DBOPTS -i -p xfs_check64 -c "check$OPTS" $1
> +    1)    xfs_db64$DBOPTS -F -i -p xfs_check64 -c "check$OPTS" $1
>        status=$?
>        ;;
>    *)    echo $USAGE 1>&2
> Index: xfsprogs-dev/db/xfs_metadump.sh
> ===================================================================
> --- xfsprogs-dev.orig/db/xfs_metadump.sh    2009-01-30  
> 06:48:14.000000000 +0000
> +++ xfsprogs-dev/db/xfs_metadump.sh    2009-01-30 06:48:20.000000000  
> +0000
> @@ -29,7 +29,7 @@
> set -- extra $@
> shift $OPTIND
> case $# in
> -    2)    xfs_db$DBOPTS -i -p xfs_metadump -c "metadump$OPTS $2" $1
> +    2)    xfs_db$DBOPTS -F -i -p xfs_metadump -c "metadump$OPTS $2"  
> $1
>        status=$?
>        ;;
>    *)    echo $USAGE 1>&2
> Index: xfsprogs-dev/man/man8/xfs_db.8
> ===================================================================
> --- xfsprogs-dev.orig/man/man8/xfs_db.8    2009-01-30  
> 06:42:43.000000000 +0000
> +++ xfsprogs-dev/man/man8/xfs_db.8    2009-01-30 06:49:13.000000000  
> +0000
> @@ -7,7 +7,7 @@
> .B \-c
> .I cmd
> ] ... [
> -.BR \-i | r | x
> +.BR \-i | r | x | F
> ] [
> .B \-f
> ] [
> @@ -53,6 +53,13 @@
> an ordinary file with
> .BR xfs_copy (8).
> .TP
> +.B \-F
> +Specifies that we want to continue even if the superblock magic is  
> not
> +correct.  For use in
> +.BR xfs_check
> +and
> +.BR xfs_metadump .
> +.TP
> .B \-i
> Allows execution on a mounted filesystem, provided it is mounted  
> read-only.
> Useful for shell scripts such as
>
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