Re: [PATCH] fsstress: add renameat2 support

[kaixuxia <xiakaixu1987@gmail.com>]

On 2019/10/15 23:05, Darrick J. Wong wrote:
> On Tue, Oct 15, 2019 at 10:34:31AM +0800, kaixuxia wrote:
>> According to the comments, after adding this fsstress renameat2 support,
>> the deadlock between the AGI and AGF with RENAME_WHITEOUT can be reproduced
>> by using customized parameters(limited to rename_whiteout and creates). If
>> this patch is okay, I will send the fsstress test patch. 
> 
> /me looks forward to that, particularly because I asked weeks ago if the
> xfs_droplink calls in xfs_rename() could try to lock the AGI after we'd
> already locked the AGF for the directory expansion, but nobody sent an
> answer...

Yeah, It's been a long time since we talked this xfs_droplink() deadlock
problem. I already have the simple fix patch, now I'm trying to get a
xfstests test patch to reproduce this deadlock problem with high possibility.
I will send the fix patch ASAP.
 
> 
>> So, Eryu, Brian, comments? 
>>
>> On 2019/10/11 15:56, kaixuxia wrote:
>>> Support the renameat2 syscall in fsstress.
>>>
>>> Signed-off-by: kaixuxia <kaixuxia@tencent.com>
>>> ---
>>>  ltp/fsstress.c | 90 +++++++++++++++++++++++++++++++++++++++++++++++++++-------
>>>  1 file changed, 79 insertions(+), 11 deletions(-)
>>>
>>> diff --git a/ltp/fsstress.c b/ltp/fsstress.c
>>> index 51976f5..21529a2 100644
>>> --- a/ltp/fsstress.c
>>> +++ b/ltp/fsstress.c
>>> @@ -44,6 +44,16 @@ io_context_t	io_ctx;
>>>  #define IOV_MAX 1024
>>>  #endif
>>>  
>>> +#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
>>> +
>>>  #define FILELEN_MAX		(32*4096)
>>>  
>>>  typedef enum {
>>> @@ -85,6 +95,9 @@ typedef enum {
>>>  	OP_READV,
>>>  	OP_REMOVEFATTR,
>>>  	OP_RENAME,
>>> +	OP_RNOREPLACE,
>>> +	OP_REXCHANGE,
>>> +	OP_RWHITEOUT,
>>>  	OP_RESVSP,
>>>  	OP_RMDIR,
>>>  	OP_SETATTR,
>>> @@ -203,6 +216,9 @@ void	readlink_f(int, long);
>>>  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);
>>>  void	setattr_f(int, long);
>>> @@ -262,6 +278,9 @@ opdesc_t	ops[] = {
>>>  	/* remove (delete) extended attribute */
>>>  	{ 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 },
>>>  	/* set attribute flag (FS_IOC_SETFLAGS ioctl) */
>>> @@ -354,7 +373,7 @@ int	open_path(pathname_t *, int);
>>>  DIR	*opendir_path(pathname_t *);
>>>  void	process_freq(char *);
>>>  int	readlink_path(pathname_t *, char *, size_t);
>>> -int	rename_path(pathname_t *, pathname_t *);
>>> +int	rename_path(pathname_t *, pathname_t *, int);
>>>  int	rmdir_path(pathname_t *);
>>>  void	separate_pathname(pathname_t *, char *, pathname_t *);
>>>  void	show_ops(int, char *);
>>> @@ -1519,7 +1538,7 @@ readlink_path(pathname_t *name, char *lbuf, size_t lbufsiz)
>>>  }
>>>  
>>>  int
>>> -rename_path(pathname_t *name1, pathname_t *name2)
>>> +rename_path(pathname_t *name1, pathname_t *name2, int mode)
>>>  {
>>>  	char		buf1[NAME_MAX + 1];
>>>  	char		buf2[NAME_MAX + 1];
>>> @@ -1528,14 +1547,14 @@ rename_path(pathname_t *name1, pathname_t *name2)
>>>  	pathname_t	newname2;
>>>  	int		rval;
>>>  
>>> -	rval = rename(name1->path, name2->path);
>>> +	rval = syscall(__NR_renameat2, AT_FDCWD, name1->path, AT_FDCWD, name2->path, mode);
> 
> For the rename(..., 0) case, would we be crippling fsstress if the
> kernel doesn't know about renameat2 and doesn't fall back to renameat()
> or regular rename()?  I guess renameat2 showed up in 3.15 which was
> quite a long time ago except in RHEL land. :)
> 
Yeah, will preserve the rename() call when it is not available in V2. 

> --D
> 
>>>  	if (rval >= 0 || errno != ENAMETOOLONG)
>>>  		return rval;
>>>  	separate_pathname(name1, buf1, &newname1);
>>>  	separate_pathname(name2, buf2, &newname2);
>>>  	if (strcmp(buf1, buf2) == 0) {
>>>  		if (chdir(buf1) == 0) {
>>> -			rval = rename_path(&newname1, &newname2);
>>> +			rval = rename_path(&newname1, &newname2, mode);
>>>  			assert(chdir("..") == 0);
>>>  		}
>>>  	} else {
>>> @@ -1555,7 +1574,7 @@ rename_path(pathname_t *name1, pathname_t *name2)
>>>  			append_pathname(&newname2, "../");
>>>  			append_pathname(&newname2, name2->path);
>>>  			if (chdir(buf1) == 0) {
>>> -				rval = rename_path(&newname1, &newname2);
>>> +				rval = rename_path(&newname1, &newname2, mode);
>>>  				assert(chdir("..") == 0);
>>>  			}
>>>  		} else {
>>> @@ -1563,7 +1582,7 @@ rename_path(pathname_t *name1, pathname_t *name2)
>>>  			append_pathname(&newname1, "../");
>>>  			append_pathname(&newname1, name1->path);
>>>  			if (chdir(buf2) == 0) {
>>> -				rval = rename_path(&newname1, &newname2);
>>> +				rval = rename_path(&newname1, &newname2, mode);
>>>  				assert(chdir("..") == 0);
>>>  			}
>>>  		}
>>> @@ -4215,8 +4234,18 @@ out:
>>>  	free_pathname(&f);
>>>  }
>>>  
>>> +struct print_flags renameat2_flags [] = {
>>> +	{ RENAME_NOREPLACE, "NOREPLACE"},
>>> +	{ RENAME_EXCHANGE, "EXCHANGE"},
>>> +	{ RENAME_WHITEOUT, "WHITEOUT"},
>>> +	{ -1, NULL}
>>> +};
>>> +
>>> +#define translate_renameat2_flags(mode)	\
>>> +	({translate_flags(mode, "|", renameat2_flags);})
>>> +
>>>  void
>>> -rename_f(int opno, long r)
>>> +do_renameat2(int opno, long r, int mode)
>>>  {
>>>  	fent_t		*dfep;
>>>  	int		e;
>>> @@ -4229,6 +4258,7 @@ rename_f(int opno, long r)
>>>  	int		parid;
>>>  	int		v;
>>>  	int		v1;
>>> +	int		fd;
>>>  
>>>  	/* get an existing path for the source of the rename */
>>>  	init_pathname(&f);
>>> @@ -4260,7 +4290,21 @@ rename_f(int opno, long r)
>>>  		free_pathname(&f);
>>>  		return;
>>>  	}
>>> -	e = rename_path(&f, &newf) < 0 ? errno : 0;
>>> +	/* Both pathnames must exist for the RENAME_EXCHANGE */
>>> +	if (mode == RENAME_EXCHANGE) {
>>> +		fd = creat_path(&newf, 0666);
>>> +		e = fd < 0 ? errno : 0;
>>> +		check_cwd();
>>> +		if (fd < 0) {
>>> +			if (v)
>>> +				printf("%d/%d: renameat2 - creat %s failed %d\n",
>>> +					procid, opno, newf.path, e);
>>> +			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;
>>> @@ -4273,12 +4317,13 @@ rename_f(int opno, long r)
>>>  		add_to_flist(flp - flist, id, parid, xattr_counter);
>>>  	}
>>>  	if (v) {
>>> -		printf("%d/%d: rename %s to %s %d\n", procid, opno, f.path,
>>> +		printf("%d/%d: rename(%s) %s to %s %d\n", procid,
>>> +			opno, translate_renameat2_flags(mode), f.path,
>>>  			newf.path, e);
>>>  		if (e == 0) {
>>> -			printf("%d/%d: rename del entry: id=%d,parent=%d\n",
>>> +			printf("%d/%d: rename source entry: id=%d,parent=%d\n",
>>>  				procid, opno, fep->id, fep->parent);
>>> -			printf("%d/%d: rename add entry: id=%d,parent=%d\n",
>>> +			printf("%d/%d: rename target entry: id=%d,parent=%d\n",
>>>  				procid, opno, id, parid);
>>>  		}
>>>  	}
>>> @@ -4287,6 +4332,29 @@ rename_f(int opno, long r)
>>>  }
>>>  
>>>  void
>>> +rename_f(int opno, long r)
>>> +{
>>> +	do_renameat2(opno, r, 0);
>>> +}
>>> +void
>>> +rnoreplace_f(int opno, long r)
>>> +{
>>> +	do_renameat2(opno, r, RENAME_NOREPLACE);
>>> +}
>>> +
>>> +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);
>>> +}
>>> +
>>> +void
>>>  resvsp_f(int opno, long r)
>>>  {
>>>  	int		e;
>>>
>>
>> -- 
>> kaixuxia

-- 
kaixuxia