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[209.6.122.159]) by smtp.gmail.com with ESMTPSA id m10sm12270594qki.74.2020.01.17.13.45.48 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Fri, 17 Jan 2020 13:45:48 -0800 (PST) Date: Fri, 17 Jan 2020 16:45:43 -0500 From: Masayoshi Mizuma To: "Dr. David Alan Gilbert (git)" Subject: Re: [PATCH 034/104] virtiofsd: passthrough_ll: add ino_map to hide lo_inode pointers Message-ID: <20200117214543.b7qxbn346nwuxly3@gabell> References: <20191212163904.159893-1-dgilbert@redhat.com> <20191212163904.159893-35-dgilbert@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191212163904.159893-35-dgilbert@redhat.com> X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 2607:f8b0:4864:20::741 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: , Cc: qemu-devel@nongnu.org, stefanha@redhat.com, vgoyal@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Thu, Dec 12, 2019 at 04:37:54PM +0000, Dr. David Alan Gilbert (git) wrote: > From: Stefan Hajnoczi > > Do not expose lo_inode pointers to clients. > > Signed-off-by: Stefan Hajnoczi > --- > tools/virtiofsd/passthrough_ll.c | 144 ++++++++++++++++++++++++------- > 1 file changed, 114 insertions(+), 30 deletions(-) > > diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthrough_ll.c > index 0a94c3e1f2..fd1d88bddf 100644 > --- a/tools/virtiofsd/passthrough_ll.c > +++ b/tools/virtiofsd/passthrough_ll.c > @@ -57,8 +57,8 @@ > > #define HAVE_POSIX_FALLOCATE 1 > /* > - * We are re-using pointers to our `struct lo_inode` and `struct > - * lo_dirp` elements as inodes. This means that we must be able to > + * 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. > */ > @@ -76,7 +76,7 @@ struct _uintptr_to_must_hold_fuse_ino_t_dummy_struct { > > struct lo_map_elem { > union { > - /* Element values will go here... */ > + struct lo_inode *inode; > ssize_t freelist; > }; > bool in_use; > @@ -97,6 +97,7 @@ struct lo_inode { > ino_t ino; > dev_t dev; > uint64_t refcount; /* protected by lo->mutex */ > + fuse_ino_t fuse_ino; > }; > > struct lo_cred { > @@ -121,6 +122,7 @@ struct lo_data { > int cache; > int timeout_set; > struct lo_inode root; /* protected by lo->mutex */ > + struct lo_map ino_map; /* protected by lo->mutex */ > }; > > static const struct fuse_opt lo_opts[] = { > @@ -145,14 +147,14 @@ static struct lo_data *lo_data(fuse_req_t req) > return (struct lo_data *)fuse_req_userdata(req); > } > > -__attribute__((unused)) static void lo_map_init(struct lo_map *map) > +static void lo_map_init(struct lo_map *map) > { > map->elems = NULL; > map->nelems = 0; > map->freelist = -1; > } > > -__attribute__((unused)) static void lo_map_destroy(struct lo_map *map) > +static void lo_map_destroy(struct lo_map *map) > { > free(map->elems); > } > @@ -183,8 +185,7 @@ static int lo_map_grow(struct lo_map *map, size_t new_nelems) > return 1; > } > > -__attribute__((unused)) static struct lo_map_elem * > -lo_map_alloc_elem(struct lo_map *map) > +static struct lo_map_elem *lo_map_alloc_elem(struct lo_map *map) > { > struct lo_map_elem *elem; > > @@ -200,8 +201,7 @@ lo_map_alloc_elem(struct lo_map *map) > return elem; > } > > -__attribute__((unused)) static struct lo_map_elem * > -lo_map_reserve(struct lo_map *map, size_t key) > +static struct lo_map_elem *lo_map_reserve(struct lo_map *map, size_t key) > { > ssize_t *prev; > > @@ -222,8 +222,7 @@ lo_map_reserve(struct lo_map *map, size_t key) > return NULL; > } > > -__attribute__((unused)) static struct lo_map_elem * > -lo_map_get(struct lo_map *map, size_t key) > +static struct lo_map_elem *lo_map_get(struct lo_map *map, size_t key) > { > if (key >= map->nelems) { > return NULL; > @@ -234,8 +233,7 @@ lo_map_get(struct lo_map *map, size_t key) > return &map->elems[key]; > } > > -__attribute__((unused)) static void lo_map_remove(struct lo_map *map, > - size_t key) > +static void lo_map_remove(struct lo_map *map, size_t key) > { > struct lo_map_elem *elem; > > @@ -254,18 +252,40 @@ __attribute__((unused)) static void lo_map_remove(struct lo_map *map, > map->freelist = key; > } > > +/* Assumes lo->mutex is held */ > +static ssize_t lo_add_inode_mapping(fuse_req_t req, struct lo_inode *inode) > +{ > + struct lo_map_elem *elem; > + > + elem = lo_map_alloc_elem(&lo_data(req)->ino_map); > + if (!elem) { > + return -1; > + } > + > + elem->inode = inode; > + return elem - lo_data(req)->ino_map.elems; > +} > + > static struct lo_inode *lo_inode(fuse_req_t req, fuse_ino_t ino) > { > - if (ino == FUSE_ROOT_ID) { > - return &lo_data(req)->root; > - } else { > - return (struct lo_inode *)(uintptr_t)ino; > + struct lo_data *lo = lo_data(req); > + struct lo_map_elem *elem; > + > + pthread_mutex_lock(&lo->mutex); > + elem = lo_map_get(&lo->ino_map, ino); > + pthread_mutex_unlock(&lo->mutex); > + > + if (!elem) { > + return NULL; > } > + > + return elem->inode; > } > > static int lo_fd(fuse_req_t req, fuse_ino_t ino) > { > - return lo_inode(req, ino)->fd; > + struct lo_inode *inode = lo_inode(req, ino); > + return inode ? inode->fd : -1; > } > > static bool lo_debug(fuse_req_t req) > @@ -337,10 +357,18 @@ static void lo_setattr(fuse_req_t req, fuse_ino_t ino, struct stat *attr, > { > int saverr; > char procname[64]; > - struct lo_inode *inode = lo_inode(req, ino); > - int ifd = inode->fd; > + struct lo_inode *inode; > + int ifd; > int res; > > + inode = lo_inode(req, ino); > + if (!inode) { > + fuse_reply_err(req, EBADF); > + return; > + } > + > + ifd = inode->fd; > + > if (valid & FUSE_SET_ATTR_MODE) { > if (fi) { > res = fchmod(fi->fh, attr->st_mode); > @@ -470,6 +498,7 @@ static int lo_do_lookup(fuse_req_t req, fuse_ino_t parent, const char *name, > inode->dev = e->attr.st_dev; > > pthread_mutex_lock(&lo->mutex); > + inode->fuse_ino = lo_add_inode_mapping(req, inode); > prev = &lo->root; > next = prev->next; > next->prev = inode; > @@ -478,7 +507,7 @@ static int lo_do_lookup(fuse_req_t req, fuse_ino_t parent, const char *name, > prev->next = inode; > pthread_mutex_unlock(&lo->mutex); > } > - e->ino = (uintptr_t)inode; > + e->ino = inode->fuse_ino; > > if (lo_debug(req)) { > fuse_log(FUSE_LOG_DEBUG, " %lli/%s -> %lli\n", > @@ -565,10 +594,16 @@ static void lo_mknod_symlink(fuse_req_t req, fuse_ino_t parent, > { > int res; > int saverr; > - struct lo_inode *dir = lo_inode(req, parent); > + struct lo_inode *dir; > struct fuse_entry_param e; > struct lo_cred old = {}; > > + dir = lo_inode(req, parent); > + if (!dir) { > + fuse_reply_err(req, EBADF); > + return; > + } > + > saverr = ENOMEM; > > saverr = lo_change_cred(req, &old); > @@ -646,10 +681,16 @@ static void lo_link(fuse_req_t req, fuse_ino_t ino, fuse_ino_t parent, > { > int res; > struct lo_data *lo = lo_data(req); > - struct lo_inode *inode = lo_inode(req, ino); > + struct lo_inode *inode; > struct fuse_entry_param e; > int saverr; > > + inode = lo_inode(req, ino); > + if (!inode) { > + fuse_reply_err(req, EBADF); > + return; > + } > + > memset(&e, 0, sizeof(struct fuse_entry_param)); > e.attr_timeout = lo->timeout; > e.entry_timeout = lo->timeout; > @@ -667,7 +708,7 @@ static void lo_link(fuse_req_t req, fuse_ino_t ino, fuse_ino_t parent, > pthread_mutex_lock(&lo->mutex); > inode->refcount++; > pthread_mutex_unlock(&lo->mutex); > - e.ino = (uintptr_t)inode; > + e.ino = inode->fuse_ino; > > if (lo_debug(req)) { > fuse_log(FUSE_LOG_DEBUG, " %lli/%s -> %lli\n", > @@ -733,10 +774,10 @@ static void unref_inode(struct lo_data *lo, struct lo_inode *inode, uint64_t n) > next->prev = prev; > prev->next = next; > > + lo_map_remove(&lo->ino_map, inode->fuse_ino); > pthread_mutex_unlock(&lo->mutex); > close(inode->fd); > free(inode); > - > } else { > pthread_mutex_unlock(&lo->mutex); > } > @@ -745,7 +786,12 @@ static void unref_inode(struct lo_data *lo, struct lo_inode *inode, uint64_t n) > static void lo_forget_one(fuse_req_t req, fuse_ino_t ino, uint64_t nlookup) > { > struct lo_data *lo = lo_data(req); > - struct lo_inode *inode = lo_inode(req, ino); > + struct lo_inode *inode; > + > + inode = lo_inode(req, ino); > + if (!inode) { > + return; > + } > > if (lo_debug(req)) { > fuse_log(FUSE_LOG_DEBUG, " forget %lli %lli -%lli\n", > @@ -1227,10 +1273,16 @@ static void lo_getxattr(fuse_req_t req, fuse_ino_t ino, const char *name, > { > char *value = NULL; > char procname[64]; > - struct lo_inode *inode = lo_inode(req, ino); > + struct lo_inode *inode; > ssize_t ret; > int saverr; > > + inode = lo_inode(req, ino); > + if (!inode) { > + fuse_reply_err(req, EBADF); > + return; > + } > + > saverr = ENOSYS; > if (!lo_data(req)->xattr) { > goto out; > @@ -1289,10 +1341,16 @@ static void lo_listxattr(fuse_req_t req, fuse_ino_t ino, size_t size) > { > char *value = NULL; > char procname[64]; > - struct lo_inode *inode = lo_inode(req, ino); > + struct lo_inode *inode; > ssize_t ret; > int saverr; > > + inode = lo_inode(req, ino); > + if (!inode) { > + fuse_reply_err(req, EBADF); > + return; > + } > + > saverr = ENOSYS; > if (!lo_data(req)->xattr) { > goto out; > @@ -1350,10 +1408,16 @@ static void lo_setxattr(fuse_req_t req, fuse_ino_t ino, const char *name, > const char *value, size_t size, int flags) > { > char procname[64]; > - struct lo_inode *inode = lo_inode(req, ino); > + struct lo_inode *inode; > ssize_t ret; > int saverr; > > + inode = lo_inode(req, ino); > + if (!inode) { > + fuse_reply_err(req, EBADF); > + return; > + } > + > saverr = ENOSYS; > if (!lo_data(req)->xattr) { > goto out; > @@ -1383,10 +1447,16 @@ out: > static void lo_removexattr(fuse_req_t req, fuse_ino_t ino, const char *name) > { > char procname[64]; > - struct lo_inode *inode = lo_inode(req, ino); > + struct lo_inode *inode; > ssize_t ret; > int saverr; > > + inode = lo_inode(req, ino); > + if (!inode) { > + fuse_reply_err(req, EBADF); > + return; > + } > + > saverr = ENOSYS; > if (!lo_data(req)->xattr) { > goto out; > @@ -1505,6 +1575,7 @@ int main(int argc, char *argv[]) > struct fuse_session *se; > struct fuse_cmdline_opts opts; > struct lo_data lo = { .debug = 0, .writeback = 0 }; > + struct lo_map_elem *root_elem; > int ret = -1; > > /* Don't mask creation mode, kernel already did that */ > @@ -1513,8 +1584,19 @@ int main(int argc, char *argv[]) > pthread_mutex_init(&lo.mutex, NULL); > lo.root.next = lo.root.prev = &lo.root; > lo.root.fd = -1; > + lo.root.fuse_ino = FUSE_ROOT_ID; > lo.cache = CACHE_NORMAL; > > + /* > + * Set up the ino map like this: > + * [0] Reserved (will not be used) > + * [1] Root inode > + */ > + lo_map_init(&lo.ino_map); > + lo_map_reserve(&lo.ino_map, 0)->in_use = false; > + root_elem = lo_map_reserve(&lo.ino_map, lo.root.fuse_ino); > + root_elem->inode = &lo.root; > + > if (fuse_parse_cmdline(&args, &opts) != 0) { > return 1; > } > @@ -1611,6 +1693,8 @@ err_out2: > err_out1: > fuse_opt_free_args(&args); > > + lo_map_destroy(&lo.ino_map); > + > if (lo.root.fd >= 0) { > close(lo.root.fd); > } Looks good to me. Reviewed-by: Masayoshi Mizuma