Re: [PATCH v3 3/4] fsstress: add EXCHANGE renameat2 support

[Brian Foster <bfoster@redhat.com>]

On Thu, Oct 31, 2019 at 02:41:48PM +0800, kaixuxia wrote:
> Support the EXCHANGE renameat2 syscall in fsstress.
> 
> In order to maintain filelist/filename integrity, we restrict
> rexchange to files of the same type.
> 
> Signed-off-by: kaixuxia <kaixuxia@tencent.com>
> ---

Looks good to me and no errors on a quick test:

Reviewed-by: Brian Foster <bfoster@redhat.com>

>  ltp/fsstress.c | 117 ++++++++++++++++++++++++++++++++++++++++++++++-----------
>  1 file changed, 96 insertions(+), 21 deletions(-)
> 
> diff --git a/ltp/fsstress.c b/ltp/fsstress.c
> index ecc1adc..0125571 100644
> --- a/ltp/fsstress.c
> +++ b/ltp/fsstress.c
> @@ -69,6 +69,9 @@ static int renameat2(int dfd1, const char *path1,
>  #ifndef RENAME_NOREPLACE
>  #define RENAME_NOREPLACE	(1 << 0)	/* Don't overwrite target */
>  #endif
> +#ifndef RENAME_EXCHANGE
> +#define RENAME_EXCHANGE		(1 << 1)	/* Exchange source and dest */
> +#endif
>  #ifndef RENAME_WHITEOUT
>  #define RENAME_WHITEOUT		(1 << 2)	/* Whiteout source */
>  #endif
> @@ -115,6 +118,7 @@ typedef enum {
>  	OP_REMOVEFATTR,
>  	OP_RENAME,
>  	OP_RNOREPLACE,
> +	OP_REXCHANGE,
>  	OP_RWHITEOUT,
>  	OP_RESVSP,
>  	OP_RMDIR,
> @@ -235,6 +239,7 @@ void	readv_f(int, long);
>  void	removefattr_f(int, long);
>  void	rename_f(int, long);
>  void	rnoreplace_f(int, long);
> +void	rexchange_f(int, long);
>  void	rwhiteout_f(int, long);
>  void	resvsp_f(int, long);
>  void	rmdir_f(int, long);
> @@ -296,6 +301,7 @@ opdesc_t	ops[] = {
>  	{ OP_REMOVEFATTR, "removefattr", removefattr_f, 1, 1 },
>  	{ OP_RENAME, "rename", rename_f, 2, 1 },
>  	{ OP_RNOREPLACE, "rnoreplace", rnoreplace_f, 2, 1 },
> +	{ OP_REXCHANGE, "rexchange", rexchange_f, 2, 1 },
>  	{ OP_RWHITEOUT, "rwhiteout", rwhiteout_f, 2, 1 },
>  	{ OP_RESVSP, "resvsp", resvsp_f, 1, 1 },
>  	{ OP_RMDIR, "rmdir", rmdir_f, 1, 1 },
> @@ -371,7 +377,8 @@ void	del_from_flist(int, int);
>  int	dirid_to_name(char *, int);
>  void	doproc(void);
>  int	fent_to_name(pathname_t *, flist_t *, fent_t *);
> -void	fix_parent(int, int);
> +bool	fents_ancestor_check(fent_t *, fent_t *);
> +void	fix_parent(int, int, bool);
>  void	free_pathname(pathname_t *);
>  int	generate_fname(fent_t *, int, pathname_t *, int *, int *);
>  int	generate_xattr_name(int, char *, int);
> @@ -1117,8 +1124,22 @@ fent_to_name(pathname_t *name, flist_t *flp, fent_t *fep)
>  	return 1;
>  }
>  
> +bool
> +fents_ancestor_check(fent_t *fep, fent_t *dfep)
> +{
> +	fent_t  *tmpfep;
> +
> +	for (tmpfep = fep; tmpfep->parent != -1;
> +	     tmpfep = dirid_to_fent(tmpfep->parent)) {
> +		if (tmpfep->parent == dfep->id)
> +			return true;
> +	}
> +
> +	return false;
> +}
> +
>  void
> -fix_parent(int oldid, int newid)
> +fix_parent(int oldid, int newid, bool swap)
>  {
>  	fent_t	*fep;
>  	flist_t	*flp;
> @@ -1129,6 +1150,8 @@ fix_parent(int oldid, int newid)
>  		for (j = 0, fep = flp->fents; j < flp->nfiles; j++, fep++) {
>  			if (fep->parent == oldid)
>  				fep->parent = newid;
> +			else if (swap && fep->parent == newid)
> +				fep->parent = oldid;
>  		}
>  	}
>  }
> @@ -4256,6 +4279,7 @@ out:
>  
>  struct print_flags renameat2_flags [] = {
>  	{ RENAME_NOREPLACE, "NOREPLACE"},
> +	{ RENAME_EXCHANGE, "EXCHANGE"},
>  	{ RENAME_WHITEOUT, "WHITEOUT"},
>  	{ -1, NULL}
>  };
> @@ -4291,41 +4315,86 @@ do_renameat2(int opno, long r, int mode)
>  		return;
>  	}
>  
> -	/* get an existing directory for the destination parent directory name */
> -	if (!get_fname(FT_DIRm, random(), NULL, NULL, &dfep, &v))
> -		parid = -1;
> -	else
> -		parid = dfep->id;
> -	v |= v1;
> +	/*
> +	 * Both pathnames must exist for the RENAME_EXCHANGE, and in
> +	 * order to maintain filelist/filename integrity, we should
> +	 * restrict exchange operation to files of the same type.
> +	 */
> +	if (mode == RENAME_EXCHANGE) {
> +		which = 1 << (flp - flist);
> +		init_pathname(&newf);
> +		if (!get_fname(which, random(), &newf, NULL, &dfep, &v)) {
> +			if (v)
> +				printf("%d/%d: rename - no target filename\n",
> +					procid, opno);
> +			free_pathname(&newf);
> +			free_pathname(&f);
> +			return;
> +		}
> +		if (which == FT_DIRm && (fents_ancestor_check(fep, dfep) ||
> +		    fents_ancestor_check(dfep, fep))) {
> +			if (v)
> +				printf("%d/%d: rename(REXCHANGE) %s and %s "
> +					"have ancestor-descendant relationship\n",
> +					procid, opno, f.path, newf.path);
> +			free_pathname(&newf);
> +			free_pathname(&f);
> +			return;
> +		}
> +		v |= v1;
> +		id = dfep->id;
> +		parid = dfep->parent;
> +	} else {
> +		/*
> +		 * Get an existing directory for the destination parent
> +		 * directory name.
> +		 */
> +		if (!get_fname(FT_DIRm, random(), NULL, NULL, &dfep, &v))
> +			parid = -1;
> +		else
> +			parid = dfep->id;
> +		v |= v1;
>  
> -	/* generate a new path using an existing parent directory in name */
> -	init_pathname(&newf);
> -	e = generate_fname(dfep, flp - flist, &newf, &id, &v1);
> -	v |= v1;
> -	if (!e) {
> -		if (v) {
> -			(void)fent_to_name(&f, &flist[FT_DIR], dfep);
> -			printf("%d/%d: rename - no filename from %s\n",
> -				procid, opno, f.path);
> +		/*
> +		 * Generate a new path using an existing parent directory
> +		 * in name.
> +		 */
> +		init_pathname(&newf);
> +		e = generate_fname(dfep, flp - flist, &newf, &id, &v1);
> +		v |= v1;
> +		if (!e) {
> +			if (v) {
> +				(void)fent_to_name(&f, &flist[FT_DIR], dfep);
> +				printf("%d/%d: rename - no filename from %s\n",
> +					procid, opno, f.path);
> +			}
> +			free_pathname(&newf);
> +			free_pathname(&f);
> +			return;
>  		}
> -		free_pathname(&newf);
> -		free_pathname(&f);
> -		return;
>  	}
>  	e = rename_path(&f, &newf, mode) < 0 ? errno : 0;
>  	check_cwd();
>  	if (e == 0) {
>  		int xattr_counter = fep->xattr_counter;
> +		bool swap = (mode == RENAME_EXCHANGE) ? true : false;
>  
>  		oldid = fep->id;
>  		oldparid = fep->parent;
>  
> +		/*
> +		 * Swap the parent ids for RENAME_EXCHANGE, and replace the
> +		 * old parent id for the others.
> +		 */
>  		if (flp - flist == FT_DIR)
> -			fix_parent(oldid, id);
> +			fix_parent(oldid, id, swap);
>  
>  		if (mode == RENAME_WHITEOUT) {
>  			fep->xattr_counter = 0;
>  			add_to_flist(flp - flist, id, parid, xattr_counter);
> +		} else if (mode == RENAME_EXCHANGE) {
> +			fep->xattr_counter = dfep->xattr_counter;
> +			dfep->xattr_counter = xattr_counter;
>  		} else {
>  			del_from_flist(flp - flist, fep - flp->fents);
>  			add_to_flist(flp - flist, id, parid, xattr_counter);
> @@ -4359,6 +4428,12 @@ rnoreplace_f(int opno, long r)
>  }
>  
>  void
> +rexchange_f(int opno, long r)
> +{
> +	do_renameat2(opno, r, RENAME_EXCHANGE);
> +}
> +
> +void
>  rwhiteout_f(int opno, long r)
>  {
>  	do_renameat2(opno, r, RENAME_WHITEOUT);
> -- 
> 1.8.3.1
>