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[83.57.172.113]) by smtp.gmail.com with ESMTPSA id i5sm34751971wrv.34.2020.01.17.05.58.57 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 17 Jan 2020 05:58:57 -0800 (PST) Subject: Re: [PATCH 035/104] virtiofsd: passthrough_ll: add dirp_map to hide lo_dirp pointers To: "Dr. David Alan Gilbert (git)" , qemu-devel@nongnu.org, stefanha@redhat.com, vgoyal@redhat.com References: <20191212163904.159893-1-dgilbert@redhat.com> <20191212163904.159893-36-dgilbert@redhat.com> From: =?UTF-8?Q?Philippe_Mathieu-Daud=c3=a9?= Message-ID: Date: Fri, 17 Jan 2020 14:58:56 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.2.2 MIME-Version: 1.0 In-Reply-To: <20191212163904.159893-36-dgilbert@redhat.com> Content-Language: en-US X-MC-Unique: 5Zhi-BigMISR2kMNkTvNag-1 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 207.211.31.120 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 12/12/19 5:37 PM, Dr. David Alan Gilbert (git) wrote: > From: Stefan Hajnoczi >=20 > Do not expose lo_dirp pointers to clients. >=20 > Signed-off-by: Stefan Hajnoczi > --- > tools/virtiofsd/passthrough_ll.c | 103 +++++++++++++++++++++++-------- > 1 file changed, 76 insertions(+), 27 deletions(-) >=20 > diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthrou= gh_ll.c > index fd1d88bddf..face8910b0 100644 > --- a/tools/virtiofsd/passthrough_ll.c > +++ b/tools/virtiofsd/passthrough_ll.c > @@ -56,27 +56,10 @@ > #include "passthrough_helpers.h" > =20 > #define HAVE_POSIX_FALLOCATE 1 > -/* > - * We are re-using pointers to our `struct lo_inode` > - * elements as inodes. This means that we must be able to > - * store uintptr_t values in a fuse_ino_t variable. The following > - * incantation checks this condition at compile time. > - */ > -#if defined(__GNUC__) && \ > - (__GNUC__ > 4 || __GNUC__ =3D=3D 4 && __GNUC_MINOR__ >=3D 6) && \ > - !defined __cplusplus > -_Static_assert(sizeof(fuse_ino_t) >=3D sizeof(uintptr_t), > - "fuse_ino_t too small to hold uintptr_t values!"); > -#else > -struct _uintptr_to_must_hold_fuse_ino_t_dummy_struct { > - unsigned _uintptr_to_must_hold_fuse_ino_t > - : ((sizeof(fuse_ino_t) >=3D sizeof(uintptr_t)) ? 1 : -1); > -}; > -#endif > - > struct lo_map_elem { > union { > struct lo_inode *inode; > + struct lo_dirp *dirp; > ssize_t freelist; > }; > bool in_use; > @@ -123,6 +106,7 @@ struct lo_data { > int timeout_set; > struct lo_inode root; /* protected by lo->mutex */ > struct lo_map ino_map; /* protected by lo->mutex */ > + struct lo_map dirp_map; /* protected by lo->mutex */ > }; > =20 > static const struct fuse_opt lo_opts[] =3D { > @@ -252,6 +236,20 @@ static void lo_map_remove(struct lo_map *map, size_t= key) > map->freelist =3D key; > } > =20 > +/* Assumes lo->mutex is held */ > +static ssize_t lo_add_dirp_mapping(fuse_req_t req, struct lo_dirp *dirp) > +{ > + struct lo_map_elem *elem; > + > + elem =3D lo_map_alloc_elem(&lo_data(req)->dirp_map); > + if (!elem) { > + return -1; > + } > + > + elem->dirp =3D dirp; > + return elem - lo_data(req)->dirp_map.elems; > +} > + > /* Assumes lo->mutex is held */ > static ssize_t lo_add_inode_mapping(fuse_req_t req, struct lo_inode *in= ode) > { > @@ -844,9 +842,19 @@ struct lo_dirp { > off_t offset; > }; > =20 > -static struct lo_dirp *lo_dirp(struct fuse_file_info *fi) > +static struct lo_dirp *lo_dirp(fuse_req_t req, struct fuse_file_info *fi= ) > { > - return (struct lo_dirp *)(uintptr_t)fi->fh; > + struct lo_data *lo =3D lo_data(req); > + struct lo_map_elem *elem; > + > + pthread_mutex_lock(&lo->mutex); > + elem =3D lo_map_get(&lo->dirp_map, fi->fh); > + pthread_mutex_unlock(&lo->mutex); > + if (!elem) { > + return NULL; > + } > + > + return elem->dirp; > } > =20 > static void lo_opendir(fuse_req_t req, fuse_ino_t ino, > @@ -856,6 +864,7 @@ static void lo_opendir(fuse_req_t req, fuse_ino_t ino= , > struct lo_data *lo =3D lo_data(req); > struct lo_dirp *d; > int fd; > + ssize_t fh; > =20 > d =3D calloc(1, sizeof(struct lo_dirp)); > if (d =3D=3D NULL) { > @@ -875,7 +884,14 @@ static void lo_opendir(fuse_req_t req, fuse_ino_t in= o, > d->offset =3D 0; > d->entry =3D NULL; > =20 > - fi->fh =3D (uintptr_t)d; > + pthread_mutex_lock(&lo->mutex); > + fh =3D lo_add_dirp_mapping(req, d); > + pthread_mutex_unlock(&lo->mutex); > + if (fh =3D=3D -1) { > + goto out_err; > + } > + > + fi->fh =3D fh; > if (lo->cache =3D=3D CACHE_ALWAYS) { > fi->keep_cache =3D 1; > } > @@ -886,6 +902,9 @@ out_errno: > error =3D errno; > out_err: > if (d) { > + if (d->dp) { > + closedir(d->dp); > + } > if (fd !=3D -1) { > close(fd); > } > @@ -903,17 +922,21 @@ static int is_dot_or_dotdot(const char *name) > static void lo_do_readdir(fuse_req_t req, fuse_ino_t ino, size_t size, > off_t offset, struct fuse_file_info *fi, int = plus) > { > - struct lo_dirp *d =3D lo_dirp(fi); > - char *buf; > + struct lo_dirp *d; > + char *buf =3D NULL; > char *p; > size_t rem =3D size; > - int err; > + int err =3D ENOMEM; > =20 > (void)ino; > =20 > + d =3D lo_dirp(req, fi); > + if (!d) { > + goto error; > + } > + > buf =3D calloc(1, size); > if (!buf) { > - err =3D ENOMEM; > goto error; > } > p =3D buf; > @@ -1011,8 +1034,21 @@ static void lo_readdirplus(fuse_req_t req, fuse_in= o_t ino, size_t size, > static void lo_releasedir(fuse_req_t req, fuse_ino_t ino, > struct fuse_file_info *fi) > { > - struct lo_dirp *d =3D lo_dirp(fi); > + struct lo_data *lo =3D lo_data(req); > + struct lo_dirp *d; > + > (void)ino; > + > + d =3D lo_dirp(req, fi); > + if (!d) { > + fuse_reply_err(req, EBADF); > + return; > + } > + > + pthread_mutex_lock(&lo->mutex); > + lo_map_remove(&lo->dirp_map, fi->fh); > + pthread_mutex_unlock(&lo->mutex); > + > closedir(d->dp); > free(d); > fuse_reply_err(req, 0); > @@ -1064,8 +1100,18 @@ static void lo_fsyncdir(fuse_req_t req, fuse_ino_t= ino, int datasync, > struct fuse_file_info *fi) > { > int res; > - int fd =3D dirfd(lo_dirp(fi)->dp); > + struct lo_dirp *d; > + int fd; > + > (void)ino; > + > + d =3D lo_dirp(req, fi); > + if (!d) { > + fuse_reply_err(req, EBADF); > + return; > + } > + > + fd =3D dirfd(d->dp); > if (datasync) { > res =3D fdatasync(fd); > } else { > @@ -1597,6 +1643,8 @@ int main(int argc, char *argv[]) > root_elem =3D lo_map_reserve(&lo.ino_map, lo.root.fuse_ino); > root_elem->inode =3D &lo.root; > =20 > + lo_map_init(&lo.dirp_map); > + > if (fuse_parse_cmdline(&args, &opts) !=3D 0) { > return 1; > } > @@ -1693,6 +1741,7 @@ err_out2: > err_out1: > fuse_opt_free_args(&args); > =20 > + lo_map_destroy(&lo.dirp_map); > lo_map_destroy(&lo.ino_map); > =20 > if (lo.root.fd >=3D 0) { >=20 Reviewed-by: Philippe Mathieu-Daud=C3=A9