On Tue, Nov 03, 2020 at 11:33:28PM +0800, Gao Xiang wrote:
> It's a bit strange pointing at some non-root bind mount target and
> then actually dumping from the actual root dir instead.
>
> Therefore, instead of searching for the root dir of the filesystem,
> just intercept all bind mount targets by checking whose ino # of
> ".." is itself with getdents.
>
> Fixes: 25195ebf107d ("xfsdump: handle bind mount targets")
> Cc: Eric Sandeen <sandeen@xxxxxxxxxx>
> Signed-off-by: Gao Xiang <hsiangkao@xxxxxxxxxx>
Reviewed-by: Bill O'Donnell <billodo@xxxxxxxxxx>
> ---
> changes since v2 (Eric):
> - error out the case where the directory cannot be read;
> - In any case, stop as soon as we have found "..";
> - update the mountpoint error message and use i18n instead;
>
> dump/content.c | 57 ++++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 57 insertions(+)
>
> diff --git a/dump/content.c b/dump/content.c
> index c11d9b4..c248e74 100644
> --- a/dump/content.c
> +++ b/dump/content.c
> @@ -511,6 +511,55 @@ static bool_t create_inv_session(
> ix_t subtreecnt,
> size_t strmix);
>
> +static bool_t
> +check_rootdir(int fd,
> + xfs_ino_t ino)
> +{
> + struct dirent *gdp;
> + size_t gdsz;
> + bool_t found = BOOL_FALSE;
> +
> + gdsz = sizeof(struct dirent) + NAME_MAX + 1;
> + if (gdsz < GETDENTSBUF_SZ_MIN)
> + gdsz = GETDENTSBUF_SZ_MIN;
> + gdp = (struct dirent *)calloc(1, gdsz);
> + assert(gdp);
> +
> + while (1) {
> + struct dirent *p;
> + int nread;
> +
> + 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));
> + break;
> + }
> +
> + /* 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, "..")) {
> + if (p->d_ino == ino)
> + found = BOOL_TRUE;
> + break;
> + }
> + }
> + }
> + free(gdp);
> + return found;
> +}
> +
> bool_t
> content_init(int argc,
> char *argv[],
> @@ -1393,6 +1442,14 @@ baseuuidbypass:
> mntpnt);
> return BOOL_FALSE;
> }
> +
> + if (!check_rootdir(sc_fsfd, rootstat.st_ino)) {
> + mlog(MLOG_ERROR,
> +_("%s is not the root of the filesystem (bind mount?) - use primary mountpoint\n"),
> + mntpnt);
> + return BOOL_FALSE;
> + }
> +
> sc_rootxfsstatp =
> (struct xfs_bstat *)calloc(1, sizeof(struct xfs_bstat));
> assert(sc_rootxfsstatp);
> --
> 2.18.1
>
