Date: Fri, 11 Oct 2019 09:21:49 +0000 From: <Zhichao1.Li@dell.com> To: <kostikbel@gmail.com> Cc: <freebsd-fs@freebsd.org>, <freebsd-drivers@freebsd.org>, <Shunchao.Hu@dell.com> Subject: RE: a issue about getting a devfs node's fullpath Message-ID: <512acd5891c94cb49bba6df379202bc6@KULX13MDC103.APAC.DELL.COM> In-Reply-To: <20191011082838.GR44691@kib.kiev.ua> References: <c6d34bd0b4114bee956b0af6d680a67f@KULX13MDC103.APAC.DELL.COM> <20191010153932.GO44691@kib.kiev.ua> <54b7173c96df43689de04f848ca86de6@KULX13MDC103.APAC.DELL.COM> <20191011082838.GR44691@kib.kiev.ua>
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sorry my bad, your pitch works exactly, thank you so much
-----Original Message-----
From: Konstantin Belousov <kostikbel@gmail.com>=20
Sent: Friday, October 11, 2019 4:29 PM
To: Li, Zhichao1 <Zhichao_Li1@Dell.com>
Cc: freebsd-fs@freebsd.org; freebsd-drivers@freebsd.org; Hu, Shunchao <Shun=
chao_Hu@Dell.com>
Subject: Re: a issue about getting a devfs node's fullpath
[EXTERNAL EMAIL]=20
On Fri, Oct 11, 2019 at 02:23:14AM +0000, Zhichao1.Li@dell.com wrote:
> Hello
> Thank you for your time
> Unfortunately it does not work, how about this way?
It does not work in which way ? I tried it and it worked as expected.
Your patch is wrong, VOP_VPTOCNP() must return parent vnode, if any.
>=20
> --- a/src/sys/fs/devfs/devfs_vnops.c
> +++ b/src/sys/fs/devfs/devfs_vnops.c
> @@ -293,7 +293,14 @@ devfs_vptocnp(struct vop_vptocnp_args *ap)
> }
> bcopy(dd->de_cdp->cdp_c.si_name, buf + i,
> strlen(dd->de_cdp->cdp_c.si_name));
> - de =3D dd->de_dir;
> + /*
> + * when dealing with VCHR
> + * the element 'si_name' already
> + * holds the full path string
> + * except rootdir, so just go
> + * to the rootdir
> + */
> + de =3D dmp->dm_rootdir;
> } else if (vp->v_type =3D=3D VDIR) {
> if (dd =3D=3D dmp->dm_rootdir) {
> *dvp =3D vp;
> @@ -307,13 +314,17 @@ devfs_vptocnp(struct vop_vptocnp_args *ap)
> }
> bcopy(dd->de_dirent->d_name, buf + i,
> dd->de_dirent->d_namlen);
> - de =3D dd;
> + /*
> + * when dealing with VDIR
> + * get its parent
> + */
> + de =3D devfs_parent_dirent(dd);
> } else {
> error =3D ENOENT;
> goto finished;
> }
> *buflen =3D i;
> - de =3D devfs_parent_dirent(de);
> + /*no need to get another parent*/
> if (de =3D=3D NULL) {
> error =3D ENOENT;
> goto finished;
>=20
> another thing is this func is called by many modules, I want to ensure mo=
difying the func this way will not impact other modules and not bring some =
bugs, would you be so kind to help me out?
>=20
> thank you
>=20
> -----Original Message-----
> From: Konstantin Belousov <kib@freebsd.org>
> Sent: Thursday, October 10, 2019 11:40 PM
> To: Li, Zhichao1 <Zhichao_Li1@Dell.com>
> Cc: freebsd-fs@freebsd.org; freebsd-drivers@freebsd.org; Hu, Shunchao=20
> <Shunchao_Hu@Dell.com>
> Subject: Re: a issue about getting a devfs node's fullpath
>=20
>=20
> [EXTERNAL EMAIL]
>=20
> On Thu, Oct 10, 2019 at 05:49:55AM +0000, Zhichao1.Li@dell.com wrote:
> > Dear freebsd developers
> > I know you're swamped, so I'll be brief.
> > I am trying to get a node's full under /dev by calling the function 'vn=
_fullpath', when dealing with things like '/dev/null' or '/dev/usb/1.0.1', =
it works well.
> > However when dealing a node under more than 2 sub directories (e.g. /de=
v/bus/usb/001/002) which I made by calling 'make_dev_s' , it goes a little=
bit different, I got a string "/dev/bus/usb/bus/usb/001/002"
> > And I found the function 'devfs_vptocnp' gets the string wrongly=20
> > when dealing multi slashes path string, I have remark the code as follo=
wed and put some comments would you please take a look, and tell me what th=
e purpose this func pass the string that way?
>=20
> Try this. Not tested.
>=20
> diff --git a/sys/fs/devfs/devfs_vnops.c b/sys/fs/devfs/devfs_vnops.c=20
> index 3b80c68e309..f20b466d88b 100644
> --- a/sys/fs/devfs/devfs_vnops.c
> +++ b/sys/fs/devfs/devfs_vnops.c
> @@ -284,38 +284,27 @@ devfs_vptocnp(struct vop_vptocnp_args *ap)
> if (error !=3D 0)
> return (error);
> =20
> - i =3D *buflen;
> + if (vp->v_type !=3D VCHR && vp->v_type !=3D VDIR) {
> + error =3D ENOENT;
> + goto finished;
> + }
> +
> dd =3D vp->v_data;
> + if (vp->v_type =3D=3D VDIR && dd =3D=3D dmp->dm_rootdir) {
> + *dvp =3D vp;
> + vref(*dvp);
> + goto finished;
> + }
> =20
> - if (vp->v_type =3D=3D VCHR) {
> - i -=3D strlen(dd->de_cdp->cdp_c.si_name);
> - if (i < 0) {
> - error =3D ENOMEM;
> - goto finished;
> - }
> - bcopy(dd->de_cdp->cdp_c.si_name, buf + i,
> - strlen(dd->de_cdp->cdp_c.si_name));
> - de =3D dd->de_dir;
> - } else if (vp->v_type =3D=3D VDIR) {
> - if (dd =3D=3D dmp->dm_rootdir) {
> - *dvp =3D vp;
> - vref(*dvp);
> - goto finished;
> - }
> - i -=3D dd->de_dirent->d_namlen;
> - if (i < 0) {
> - error =3D ENOMEM;
> - goto finished;
> - }
> - bcopy(dd->de_dirent->d_name, buf + i,
> - dd->de_dirent->d_namlen);
> - de =3D dd;
> - } else {
> - error =3D ENOENT;
> + i =3D *buflen;
> + i -=3D dd->de_dirent->d_namlen;
> + if (i < 0) {
> + error =3D ENOMEM;
> goto finished;
> }
> + bcopy(dd->de_dirent->d_name, buf + i, dd->de_dirent->d_namlen);
> *buflen =3D i;
> - de =3D devfs_parent_dirent(de);
> + de =3D devfs_parent_dirent(dd);
> if (de =3D=3D NULL) {
> error =3D ENOENT;
> goto finished;
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