Commit 7b1373dd authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'fuse-update-5.4' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse

Pull fuse updates from Miklos Szeredi:

 - Continue separating the transport (user/kernel communication) and the
   filesystem layers of fuse. Getting rid of most layering violations
   will allow for easier cleanup and optimization later on.

 - Prepare for the addition of the virtio-fs filesystem. The actual
   filesystem will be introduced by a separate pull request.

 - Convert to new mount API.

 - Various fixes, optimizations and cleanups.

* tag 'fuse-update-5.4' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse: (55 commits)
  fuse: Make fuse_args_to_req static
  fuse: fix memleak in cuse_channel_open
  fuse: fix beyond-end-of-page access in fuse_parse_cache()
  fuse: unexport fuse_put_request
  fuse: kmemcg account fs data
  fuse: on 64-bit store time in d_fsdata directly
  fuse: fix missing unlock_page in fuse_writepage()
  fuse: reserve byteswapped init opcodes
  fuse: allow skipping control interface and forced unmount
  fuse: dissociate DESTROY from fuseblk
  fuse: delete dentry if timeout is zero
  fuse: separate fuse device allocation and installation in fuse_conn
  fuse: add fuse_iqueue_ops callbacks
  fuse: extract fuse_fill_super_common()
  fuse: export fuse_dequeue_forget() function
  fuse: export fuse_get_unique()
  fuse: export fuse_send_init_request()
  fuse: export fuse_len_args()
  fuse: export fuse_end_request()
  fuse: fix request limit
  ...
parents 301310c6 5addcd5d
......@@ -504,7 +504,6 @@ void put_fs_context(struct fs_context *fc)
put_net(fc->net_ns);
put_user_ns(fc->user_ns);
put_cred(fc->cred);
kfree(fc->subtype);
put_fc_log(fc);
put_filesystem(fc->fs_type);
kfree(fc->source);
......@@ -571,17 +570,6 @@ static int legacy_parse_param(struct fs_context *fc, struct fs_parameter *param)
return 0;
}
if ((fc->fs_type->fs_flags & FS_HAS_SUBTYPE) &&
strcmp(param->key, "subtype") == 0) {
if (param->type != fs_value_is_string)
return invalf(fc, "VFS: Legacy: Non-string subtype");
if (fc->subtype)
return invalf(fc, "VFS: Legacy: Multiple subtype");
fc->subtype = param->string;
param->string = NULL;
return 0;
}
if (ctx->param_type == LEGACY_FS_MONOLITHIC_PARAMS)
return invalf(fc, "VFS: Legacy: Can't mix monolithic and individual options");
......@@ -738,8 +726,6 @@ void vfs_clean_context(struct fs_context *fc)
fc->s_fs_info = NULL;
fc->sb_flags = 0;
security_free_mnt_opts(&fc->security);
kfree(fc->subtype);
fc->subtype = NULL;
kfree(fc->source);
fc->source = NULL;
......
......@@ -142,11 +142,10 @@ static int cuse_open(struct inode *inode, struct file *file)
static int cuse_release(struct inode *inode, struct file *file)
{
struct fuse_inode *fi = get_fuse_inode(inode);
struct fuse_file *ff = file->private_data;
struct fuse_conn *fc = ff->fc;
fuse_sync_release(fi, ff, file->f_flags);
fuse_sync_release(NULL, ff, file->f_flags);
fuse_conn_put(fc);
return 0;
......@@ -299,6 +298,14 @@ static void cuse_gendev_release(struct device *dev)
kfree(dev);
}
struct cuse_init_args {
struct fuse_args_pages ap;
struct cuse_init_in in;
struct cuse_init_out out;
struct page *page;
struct fuse_page_desc desc;
};
/**
* cuse_process_init_reply - finish initializing CUSE channel
*
......@@ -306,21 +313,22 @@ static void cuse_gendev_release(struct device *dev)
* required data structures for it. Please read the comment at the
* top of this file for high level overview.
*/
static void cuse_process_init_reply(struct fuse_conn *fc, struct fuse_req *req)
static void cuse_process_init_reply(struct fuse_conn *fc,
struct fuse_args *args, int error)
{
struct cuse_init_args *ia = container_of(args, typeof(*ia), ap.args);
struct fuse_args_pages *ap = &ia->ap;
struct cuse_conn *cc = fc_to_cc(fc), *pos;
struct cuse_init_out *arg = req->out.args[0].value;
struct page *page = req->pages[0];
struct cuse_init_out *arg = &ia->out;
struct page *page = ap->pages[0];
struct cuse_devinfo devinfo = { };
struct device *dev;
struct cdev *cdev;
dev_t devt;
int rc, i;
if (req->out.h.error ||
arg->major != FUSE_KERNEL_VERSION || arg->minor < 11) {
if (error || arg->major != FUSE_KERNEL_VERSION || arg->minor < 11)
goto err;
}
fc->minor = arg->minor;
fc->max_read = max_t(unsigned, arg->max_read, 4096);
......@@ -329,7 +337,7 @@ static void cuse_process_init_reply(struct fuse_conn *fc, struct fuse_req *req)
/* parse init reply */
cc->unrestricted_ioctl = arg->flags & CUSE_UNRESTRICTED_IOCTL;
rc = cuse_parse_devinfo(page_address(page), req->out.args[1].size,
rc = cuse_parse_devinfo(page_address(page), ap->args.out_args[1].size,
&devinfo);
if (rc)
goto err;
......@@ -396,7 +404,7 @@ static void cuse_process_init_reply(struct fuse_conn *fc, struct fuse_req *req)
dev_set_uevent_suppress(dev, 0);
kobject_uevent(&dev->kobj, KOBJ_ADD);
out:
kfree(arg);
kfree(ia);
__free_page(page);
return;
......@@ -415,55 +423,49 @@ err:
static int cuse_send_init(struct cuse_conn *cc)
{
int rc;
struct fuse_req *req;
struct page *page;
struct fuse_conn *fc = &cc->fc;
struct cuse_init_in *arg;
void *outarg;
struct cuse_init_args *ia;
struct fuse_args_pages *ap;
BUILD_BUG_ON(CUSE_INIT_INFO_MAX > PAGE_SIZE);
req = fuse_get_req_for_background(fc, 1);
if (IS_ERR(req)) {
rc = PTR_ERR(req);
goto err;
}
rc = -ENOMEM;
page = alloc_page(GFP_KERNEL | __GFP_ZERO);
if (!page)
goto err_put_req;
goto err;
outarg = kzalloc(sizeof(struct cuse_init_out), GFP_KERNEL);
if (!outarg)
ia = kzalloc(sizeof(*ia), GFP_KERNEL);
if (!ia)
goto err_free_page;
arg = &req->misc.cuse_init_in;
arg->major = FUSE_KERNEL_VERSION;
arg->minor = FUSE_KERNEL_MINOR_VERSION;
arg->flags |= CUSE_UNRESTRICTED_IOCTL;
req->in.h.opcode = CUSE_INIT;
req->in.numargs = 1;
req->in.args[0].size = sizeof(struct cuse_init_in);
req->in.args[0].value = arg;
req->out.numargs = 2;
req->out.args[0].size = sizeof(struct cuse_init_out);
req->out.args[0].value = outarg;
req->out.args[1].size = CUSE_INIT_INFO_MAX;
req->out.argvar = 1;
req->out.argpages = 1;
req->pages[0] = page;
req->page_descs[0].length = req->out.args[1].size;
req->num_pages = 1;
req->end = cuse_process_init_reply;
fuse_request_send_background(fc, req);
return 0;
ap = &ia->ap;
ia->in.major = FUSE_KERNEL_VERSION;
ia->in.minor = FUSE_KERNEL_MINOR_VERSION;
ia->in.flags |= CUSE_UNRESTRICTED_IOCTL;
ap->args.opcode = CUSE_INIT;
ap->args.in_numargs = 1;
ap->args.in_args[0].size = sizeof(ia->in);
ap->args.in_args[0].value = &ia->in;
ap->args.out_numargs = 2;
ap->args.out_args[0].size = sizeof(ia->out);
ap->args.out_args[0].value = &ia->out;
ap->args.out_args[1].size = CUSE_INIT_INFO_MAX;
ap->args.out_argvar = 1;
ap->args.out_pages = 1;
ap->num_pages = 1;
ap->pages = &ia->page;
ap->descs = &ia->desc;
ia->page = page;
ia->desc.length = ap->args.out_args[1].size;
ap->args.end = cuse_process_init_reply;
rc = fuse_simple_background(fc, &ap->args, GFP_KERNEL);
if (rc) {
kfree(ia);
err_free_page:
__free_page(page);
err_put_req:
fuse_put_request(fc, req);
__free_page(page);
}
err:
return rc;
}
......@@ -504,9 +506,9 @@ static int cuse_channel_open(struct inode *inode, struct file *file)
* Limit the cuse channel to requests that can
* be represented in file->f_cred->user_ns.
*/
fuse_conn_init(&cc->fc, file->f_cred->user_ns);
fuse_conn_init(&cc->fc, file->f_cred->user_ns, &fuse_dev_fiq_ops, NULL);
fud = fuse_dev_alloc(&cc->fc);
fud = fuse_dev_alloc_install(&cc->fc);
if (!fud) {
kfree(cc);
return -ENOMEM;
......@@ -519,6 +521,7 @@ static int cuse_channel_open(struct inode *inode, struct file *file)
rc = cuse_send_init(cc);
if (rc) {
fuse_dev_free(fud);
fuse_conn_put(&cc->fc);
return rc;
}
file->private_data = fud;
......
This diff is collapsed.
......@@ -24,20 +24,54 @@ static void fuse_advise_use_readdirplus(struct inode *dir)
set_bit(FUSE_I_ADVISE_RDPLUS, &fi->state);
}
#if BITS_PER_LONG >= 64
static inline void __fuse_dentry_settime(struct dentry *entry, u64 time)
{
entry->d_fsdata = (void *) time;
}
static inline u64 fuse_dentry_time(const struct dentry *entry)
{
return (u64)entry->d_fsdata;
}
#else
union fuse_dentry {
u64 time;
struct rcu_head rcu;
};
static inline void fuse_dentry_settime(struct dentry *entry, u64 time)
static inline void __fuse_dentry_settime(struct dentry *dentry, u64 time)
{
((union fuse_dentry *) entry->d_fsdata)->time = time;
((union fuse_dentry *) dentry->d_fsdata)->time = time;
}
static inline u64 fuse_dentry_time(struct dentry *entry)
static inline u64 fuse_dentry_time(const struct dentry *entry)
{
return ((union fuse_dentry *) entry->d_fsdata)->time;
}
#endif
static void fuse_dentry_settime(struct dentry *dentry, u64 time)
{
struct fuse_conn *fc = get_fuse_conn_super(dentry->d_sb);
bool delete = !time && fc->delete_stale;
/*
* Mess with DCACHE_OP_DELETE because dput() will be faster without it.
* Don't care about races, either way it's just an optimization
*/
if ((!delete && (dentry->d_flags & DCACHE_OP_DELETE)) ||
(delete && !(dentry->d_flags & DCACHE_OP_DELETE))) {
spin_lock(&dentry->d_lock);
if (!delete)
dentry->d_flags &= ~DCACHE_OP_DELETE;
else
dentry->d_flags |= DCACHE_OP_DELETE;
spin_unlock(&dentry->d_lock);
}
__fuse_dentry_settime(dentry, time);
}
/*
* FUSE caches dentries and attributes with separate timeout. The
......@@ -139,14 +173,14 @@ static void fuse_lookup_init(struct fuse_conn *fc, struct fuse_args *args,
struct fuse_entry_out *outarg)
{
memset(outarg, 0, sizeof(struct fuse_entry_out));
args->in.h.opcode = FUSE_LOOKUP;
args->in.h.nodeid = nodeid;
args->in.numargs = 1;
args->in.args[0].size = name->len + 1;
args->in.args[0].value = name->name;
args->out.numargs = 1;
args->out.args[0].size = sizeof(struct fuse_entry_out);
args->out.args[0].value = outarg;
args->opcode = FUSE_LOOKUP;
args->nodeid = nodeid;
args->in_numargs = 1;
args->in_args[0].size = name->len + 1;
args->in_args[0].value = name->name;
args->out_numargs = 1;
args->out_args[0].size = sizeof(struct fuse_entry_out);
args->out_args[0].value = outarg;
}
/*
......@@ -242,9 +276,11 @@ invalid:
goto out;
}
#if BITS_PER_LONG < 64
static int fuse_dentry_init(struct dentry *dentry)
{
dentry->d_fsdata = kzalloc(sizeof(union fuse_dentry), GFP_KERNEL);
dentry->d_fsdata = kzalloc(sizeof(union fuse_dentry),
GFP_KERNEL_ACCOUNT | __GFP_RECLAIMABLE);
return dentry->d_fsdata ? 0 : -ENOMEM;
}
......@@ -254,16 +290,27 @@ static void fuse_dentry_release(struct dentry *dentry)
kfree_rcu(fd, rcu);
}
#endif
static int fuse_dentry_delete(const struct dentry *dentry)
{
return time_before64(fuse_dentry_time(dentry), get_jiffies_64());
}
const struct dentry_operations fuse_dentry_operations = {
.d_revalidate = fuse_dentry_revalidate,
.d_delete = fuse_dentry_delete,
#if BITS_PER_LONG < 64
.d_init = fuse_dentry_init,
.d_release = fuse_dentry_release,
#endif
};
const struct dentry_operations fuse_root_dentry_operations = {
#if BITS_PER_LONG < 64
.d_init = fuse_dentry_init,
.d_release = fuse_dentry_release,
#endif
};
int fuse_valid_type(int m)
......@@ -410,18 +457,18 @@ static int fuse_create_open(struct inode *dir, struct dentry *entry,
inarg.flags = flags;
inarg.mode = mode;
inarg.umask = current_umask();
args.in.h.opcode = FUSE_CREATE;
args.in.h.nodeid = get_node_id(dir);
args.in.numargs = 2;
args.in.args[0].size = sizeof(inarg);
args.in.args[0].value = &inarg;
args.in.args[1].size = entry->d_name.len + 1;
args.in.args[1].value = entry->d_name.name;
args.out.numargs = 2;
args.out.args[0].size = sizeof(outentry);
args.out.args[0].value = &outentry;
args.out.args[1].size = sizeof(outopen);
args.out.args[1].value = &outopen;
args.opcode = FUSE_CREATE;
args.nodeid = get_node_id(dir);
args.in_numargs = 2;
args.in_args[0].size = sizeof(inarg);
args.in_args[0].value = &inarg;
args.in_args[1].size = entry->d_name.len + 1;
args.in_args[1].value = entry->d_name.name;
args.out_numargs = 2;
args.out_args[0].size = sizeof(outentry);
args.out_args[0].value = &outentry;
args.out_args[1].size = sizeof(outopen);
args.out_args[1].value = &outopen;
err = fuse_simple_request(fc, &args);
if (err)
goto out_free_ff;
......@@ -526,10 +573,10 @@ static int create_new_entry(struct fuse_conn *fc, struct fuse_args *args,
return -ENOMEM;
memset(&outarg, 0, sizeof(outarg));
args->in.h.nodeid = get_node_id(dir);
args->out.numargs = 1;
args->out.args[0].size = sizeof(outarg);
args->out.args[0].value = &outarg;
args->nodeid = get_node_id(dir);
args->out_numargs = 1;
args->out_args[0].size = sizeof(outarg);
args->out_args[0].value = &outarg;
err = fuse_simple_request(fc, args);
if (err)
goto out_put_forget_req;
......@@ -582,12 +629,12 @@ static int fuse_mknod(struct inode *dir, struct dentry *entry, umode_t mode,
inarg.mode = mode;
inarg.rdev = new_encode_dev(rdev);
inarg.umask = current_umask();
args.in.h.opcode = FUSE_MKNOD;
args.in.numargs = 2;
args.in.args[0].size = sizeof(inarg);
args.in.args[0].value = &inarg;
args.in.args[1].size = entry->d_name.len + 1;
args.in.args[1].value = entry->d_name.name;
args.opcode = FUSE_MKNOD;
args.in_numargs = 2;
args.in_args[0].size = sizeof(inarg);
args.in_args[0].value = &inarg;
args.in_args[1].size = entry->d_name.len + 1;
args.in_args[1].value = entry->d_name.name;
return create_new_entry(fc, &args, dir, entry, mode);
}
......@@ -609,12 +656,12 @@ static int fuse_mkdir(struct inode *dir, struct dentry *entry, umode_t mode)
memset(&inarg, 0, sizeof(inarg));
inarg.mode = mode;
inarg.umask = current_umask();
args.in.h.opcode = FUSE_MKDIR;
args.in.numargs = 2;
args.in.args[0].size = sizeof(inarg);
args.in.args[0].value = &inarg;
args.in.args[1].size = entry->d_name.len + 1;
args.in.args[1].value = entry->d_name.name;
args.opcode = FUSE_MKDIR;
args.in_numargs = 2;
args.in_args[0].size = sizeof(inarg);
args.in_args[0].value = &inarg;
args.in_args[1].size = entry->d_name.len + 1;
args.in_args[1].value = entry->d_name.name;
return create_new_entry(fc, &args, dir, entry, S_IFDIR);
}
......@@ -625,12 +672,12 @@ static int fuse_symlink(struct inode *dir, struct dentry *entry,
unsigned len = strlen(link) + 1;
FUSE_ARGS(args);
args.in.h.opcode = FUSE_SYMLINK;
args.in.numargs = 2;
args.in.args[0].size = entry->d_name.len + 1;
args.in.args[0].value = entry->d_name.name;
args.in.args[1].size = len;
args.in.args[1].value = link;
args.opcode = FUSE_SYMLINK;
args.in_numargs = 2;
args.in_args[0].size = entry->d_name.len + 1;
args.in_args[0].value = entry->d_name.name;
args.in_args[1].size = len;
args.in_args[1].value = link;
return create_new_entry(fc, &args, dir, entry, S_IFLNK);
}
......@@ -648,11 +695,11 @@ static int fuse_unlink(struct inode *dir, struct dentry *entry)
struct fuse_conn *fc = get_fuse_conn(dir);
FUSE_ARGS(args);
args.in.h.opcode = FUSE_UNLINK;
args.in.h.nodeid = get_node_id(dir);
args.in.numargs = 1;
args.in.args[0].size = entry->d_name.len + 1;
args.in.args[0].value = entry->d_name.name;
args.opcode = FUSE_UNLINK;
args.nodeid = get_node_id(dir);
args.in_numargs = 1;
args.in_args[0].size = entry->d_name.len + 1;
args.in_args[0].value = entry->d_name.name;
err = fuse_simple_request(fc, &args);
if (!err) {
struct inode *inode = d_inode(entry);
......@@ -684,11 +731,11 @@ static int fuse_rmdir(struct inode *dir, struct dentry *entry)
struct fuse_conn *fc = get_fuse_conn(dir);
FUSE_ARGS(args);
args.in.h.opcode = FUSE_RMDIR;
args.in.h.nodeid = get_node_id(dir);
args.in.numargs = 1;
args.in.args[0].size = entry->d_name.len + 1;
args.in.args[0].value = entry->d_name.name;
args.opcode = FUSE_RMDIR;
args.nodeid = get_node_id(dir);
args.in_numargs = 1;
args.in_args[0].size = entry->d_name.len + 1;
args.in_args[0].value = entry->d_name.name;
err = fuse_simple_request(fc, &args);
if (!err) {
clear_nlink(d_inode(entry));
......@@ -711,15 +758,15 @@ static int fuse_rename_common(struct inode *olddir, struct dentry *oldent,
memset(&inarg, 0, argsize);
inarg.newdir = get_node_id(newdir);
inarg.flags = flags;
args.in.h.opcode = opcode;
args.in.h.nodeid = get_node_id(olddir);
args.in.numargs = 3;
args.in.args[0].size = argsize;
args.in.args[0].value = &inarg;
args.in.args[1].size = oldent->d_name.len + 1;
args.in.args[1].value = oldent->d_name.name;
args.in.args[2].size = newent->d_name.len + 1;
args.in.args[2].value = newent->d_name.name;
args.opcode = opcode;
args.nodeid = get_node_id(olddir);
args.in_numargs = 3;
args.in_args[0].size = argsize;
args.in_args[0].value = &inarg;
args.in_args[1].size = oldent->d_name.len + 1;
args.in_args[1].value = oldent->d_name.name;
args.in_args[2].size = newent->d_name.len + 1;
args.in_args[2].value = newent->d_name.name;
err = fuse_simple_request(fc, &args);
if (!err) {
/* ctime changes */
......@@ -796,12 +843,12 @@ static int fuse_link(struct dentry *entry, struct inode *newdir,
memset(&inarg, 0, sizeof(inarg));
inarg.oldnodeid = get_node_id(inode);
args.in.h.opcode = FUSE_LINK;
args.in.numargs = 2;
args.in.args[0].size = sizeof(inarg);
args.in.args[0].value = &inarg;
args.in.args[1].size = newent->d_name.len + 1;
args.in.args[1].value = newent->d_name.name;
args.opcode = FUSE_LINK;
args.in_numargs = 2;
args.in_args[0].size = sizeof(inarg);
args.in_args[0].value = &inarg;
args.in_args[1].size = newent->d_name.len + 1;
args.in_args[1].value = newent->d_name.name;
err = create_new_entry(fc, &args, newdir, newent, inode->i_mode);
/* Contrary to "normal" filesystems it can happen that link
makes two "logical" inodes point to the same "physical"
......@@ -884,14 +931,14 @@ static int fuse_do_getattr(struct inode *inode, struct kstat *stat,
inarg.getattr_flags |= FUSE_GETATTR_FH;
inarg.fh = ff->fh;
}
args.in.h.opcode = FUSE_GETATTR;
args.in.h.nodeid = get_node_id(inode);
args.in.numargs = 1;
args.in.args[0].size = sizeof(inarg);
args.in.args[0].value = &inarg;
args.out.numargs = 1;
args.out.args[0].size = sizeof(outarg);
args.out.args[0].value = &outarg;
args.opcode = FUSE_GETATTR;
args.nodeid = get_node_id(inode);
args.in_numargs = 1;
args.in_args[0].size = sizeof(inarg);
args.in_args[0].value = &inarg;
args.out_numargs = 1;
args.out_args[0].size = sizeof(outarg);
args.out_args[0].value = &outarg;
err = fuse_simple_request(fc, &args);
if (!err) {
if ((inode->i_mode ^ outarg.attr.mode) & S_IFMT) {
......@@ -1056,11 +1103,11 @@ static int fuse_access(struct inode *inode, int mask)
memset(&inarg, 0, sizeof(inarg));
inarg.mask = mask & (MAY_READ | MAY_WRITE | MAY_EXEC);
args.in.h.opcode = FUSE_ACCESS;
args.in.h.nodeid = get_node_id(inode);
args.in.numargs = 1;
args.in.args[0].size = sizeof(inarg);
args.in.args[0].value = &inarg;
args.opcode = FUSE_ACCESS;
args.nodeid = get_node_id(inode);
args.in_numargs = 1;
args.in_args[0].size = sizeof(inarg);
args.in_args[0].value = &inarg;
err = fuse_simple_request(fc, &args);
if (err == -ENOSYS) {
fc->no_access = 1;
......@@ -1152,38 +1199,36 @@ static int fuse_permission(struct inode *inode, int mask)
static int fuse_readlink_page(struct inode *inode, struct page *page)
{
struct fuse_conn *fc = get_fuse_conn(inode);
struct fuse_req *req;
int err;
struct fuse_page_desc desc = { .length = PAGE_SIZE - 1 };
struct fuse_args_pages ap = {
.num_pages = 1,
.pages = &page,
.descs = &desc,
};
char *link;
ssize_t res;
ap.args.opcode = FUSE_READLINK;
ap.args.nodeid = get_node_id(inode);
ap.args.out_pages = true;
ap.args.out_argvar = true;
ap.args.page_zeroing = true;
ap.args.out_numargs = 1;
ap.args.out_args[0].size = desc.length;
res = fuse_simple_request(fc, &ap.args);
req = fuse_get_req(fc, 1);
if (IS_ERR(req))
return PTR_ERR(req);
req->out.page_zeroing = 1;
req->out.argpages = 1;
req->num_pages = 1;
req->pages[0] = page;
req->page_descs[0].length = PAGE_SIZE - 1;
req->in.h.opcode = FUSE_READLINK;
req->in.h.nodeid = get_node_id(inode);
req->out.argvar = 1;
req->out.numargs = 1;
req->out.args[0].size = PAGE_SIZE - 1;
fuse_request_send(fc, req);
err = req->out.h.error;
fuse_invalidate_atime(inode);
if (!err) {
char *link = page_address(page);
size_t len = req->out.args[0].size;
if (res < 0)