Re: [PATCH v2 2/2] xfsdump: intercept bind mount targets

[Gao Xiang <hsiangkao@redhat.com>]

Hi Eric,

On Tue, Nov 03, 2020 at 09:03:48AM -0600, Eric Sandeen wrote:
> On 11/2/20 8:33 PM, Gao Xiang wrote:

...

> > +
> > +		nread = getdents_wrap(fd, (char *)gdp, gdsz);
> > +		/*
> > +		 * negative count indicates something very bad happened;
> > +		 * try to gracefully end this dir.
> > +		 */
> > +		if (nread < 0) {
> > +			mlog(MLOG_NORMAL | MLOG_WARNING,
> > +_("unable to read dirents for directory ino %llu: %s\n"),
> > +			      ino, strerror(errno));
> > +			/* !!! curtis looked at this, and pointed out that
> 
> Nobody knows who curtis is, I think we can drop this comment now ;)
> If we can't read the directory I think it's fine to simply error out here.

This was copied from dump_dir(), ok, I will error out this.

> 
> > +			 * we could take some recovery action here. if the
> > +			 * errno is appropriate, lseek64 to the value of
> > +			 * doff field of the last dirent successfully
> > +			 * obtained, and contiue the loop.
> > +			 */
> > +			nread = 0; /* pretend we are done */
> > +		}
> > +
> > +		/* no more directory entries: break; */
> > +		if (!nread)
> > +			break;
> > +
> > +		for (p = gdp; nread > 0;
> > +		     nread -= (int)p->d_reclen,
> > +		     assert(nread >= 0),
> > +		     p = (struct dirent *)((char *)p + p->d_reclen)) {
> > +			if (!strcmp(p->d_name, "..") && p->d_ino == ino) {
> > +				mlog(MLOG_DEBUG, "FOUND: name %s d_ino %llu\n",
> > +				     p->d_name, ino);
> > +				free(gdp);
> > +				return BOOL_TRUE;
> > +			}
> 
> I think we can stop as soon as we have found ".." yes?  No need to continue
> iterating the directory, either ".." is what we wanted, or it's not, but either
> way we are done when we have checked it.  On the off chance that we have
> a very large root dir, stopping early might be good.

Yes, that is correct.

> 
> > +		}
> > +	}
> > +	free(gdp);
> > +	return BOOL_FALSE;
> > +}
> > +
> >  bool_t
> >  content_init(int argc,
> >  	      char *argv[],
> > @@ -1393,6 +1448,13 @@ baseuuidbypass:
> >  			      mntpnt);
> >  			return BOOL_FALSE;
> >  		}
> > +
> > +		if (!check_rootdir(sc_fsfd, rootstat.st_ino)) {
> > +			mlog(MLOG_ERROR,
> > +"oops, seems to be a bind mount, please use the actual mountpoint instead\n");
> 
> Could there be any other reason for this failure?  Maybe something like:
> 
> 			mlog(MLOG_ERROR,
> _("%s is not the root of the filesystem (bind mount?) - use primary mountpoint\n"),
> 				mntpnt);
> 
> or similar?
> 
> in any case I think it needs the i18n _("...") treatment.

Ok, will quickly send the fixed version about this!


Thanks for your review!


Thanks,
Gao Xiang

> 
> Thanks!
> 
> -Eric
> 
> > +			return BOOL_FALSE;
> > +		}
> > +
> >  		sc_rootxfsstatp =
> >  			(struct xfs_bstat *)calloc(1, sizeof(struct xfs_bstat));
> >  		assert(sc_rootxfsstatp);
> > 
>