On Wed, Jan 04, 2017 at 01:42:02PM -0600, Eric Sandeen wrote:
> Today, xfsdump looks at the mount point it was handed, gets
> the inode of that directory, and assumes that it is the
> filesystem's root inode.
>
> This doesn't work if we have bind-mounted a subdirectory
> somewhere, and point xfsdump at that. The inode number retrieved
> is not the filesystem's root inode number, and because this
> goes into the dump header and gets checked on restore, things
> go badly when the root inode found in the dump does not match
> the root inode in the dump header:
>
> # mkfs.xfs -dfile,name=fsfile,size=16g
> # mkdir mnt
> # mount -o loop fsfile mnt
> # mkdir -p mnt/dir
> # mkdir -p mnt2/dir
> # mount -o bind mnt/dir mnt2/dir
> # xfsdump -v trace -J -F -l 0 - `pwd`/mnt2/dir | xfsdump/restore/xfsrestore -v trace -t -
> ...
> xfsrestore: tree.c:759: tree_begindir: Assertion `ino != persp->p_rootino || hardh == persp->p_rooth' failed.
> #
>
> Fix this by using bulkstat to get the first valid inode in the filesystem.
> Compare this to the inode number of the mounted directory, and if they
> differ, issue a notice that this may be a bind mount (which means that
> more than just the tree under the mount will be dumped; the whole
> filesystem is dumped by default).
>
> Reported-by: Jason L Tibbitts III <tibbs@xxxxxxxxxxx>
> Signed-off-by: Eric Sandeen <sandeen@xxxxxxxxxx>
> ---
Reviewed-by: Brian Foster <bfoster@xxxxxxxxxx>
>
> This passes xfstests dump group, FWIW, as well as the
> testcase above (which probably should get turned into a test)
>
> diff --git a/dump/content.c b/dump/content.c
> index 1e86292..5a3c02f 100644
> --- a/dump/content.c
> +++ b/dump/content.c
> @@ -1381,10 +1381,17 @@ baseuuidbypass:
> }
>
> /* figure out the ino for the root directory of the fs
> - * and get its xfs_bstat_t for inomap_build()
> + * and get its xfs_bstat_t for inomap_build(). This could
> + * be a bind mount; don't ask for the mount point inode,
> + * find the actual lowest inode number in the filesystem.
> */
> {
> stat64_t rootstat;
> + xfs_ino_t lastino = 0;
> + int ocount = 0;
> + xfs_fsop_bulkreq_t bulkreq;
> +
> + /* Get the inode of the mount point */
> rval = fstat64( sc_fsfd, &rootstat );
> if ( rval ) {
> mlog( MLOG_NORMAL, _(
> @@ -1396,11 +1403,21 @@ baseuuidbypass:
> ( xfs_bstat_t * )calloc( 1, sizeof( xfs_bstat_t ));
> assert( sc_rootxfsstatp );
>
> - if ( bigstat_one( sc_fsfd, rootstat.st_ino, sc_rootxfsstatp) < 0 ) {
> + /* Get the first valid (i.e. root) inode in this fs */
> + bulkreq.lastip = (__u64 *)&lastino;
> + bulkreq.icount = 1;
> + bulkreq.ubuffer = sc_rootxfsstatp;
> + bulkreq.ocount = &ocount;
> + if (ioctl(sc_fsfd, XFS_IOC_FSBULKSTAT, &bulkreq) < 0) {
> mlog( MLOG_ERROR,
> _("failed to get bulkstat information for root inode\n"));
> return BOOL_FALSE;
> }
> +
> + if (sc_rootxfsstatp->bs_ino != rootstat.st_ino)
> + mlog ( MLOG_NORMAL | MLOG_NOTE,
> + _("root ino %lld differs from mount dir ino %lld, bind mount?\n"),
> + sc_rootxfsstatp->bs_ino, rootstat.st_ino);
> }
>
> /* alloc a file system handle, to be used with the jdm_open()
>
>
>
> --
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