blob: 75902be14106247c94184ef06e66a6f60650d927 [file] [log] [blame]
/*
FUSE: Filesystem in Userspace
Copyright (C) 2001-2008 Miklos Szeredi <miklos@szeredi.hu>
This program can be distributed under the terms of the GNU GPL.
See the file COPYING.
*/
#include "fuse_i.h"
#include <linux/pagemap.h>
#include <linux/slab.h>
#include <linux/file.h>
#include <linux/seq_file.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/fs_context.h>
#include <linux/fs_parser.h>
#include <linux/statfs.h>
#include <linux/random.h>
#include <linux/sched.h>
#include <linux/exportfs.h>
#include <linux/posix_acl.h>
#include <linux/pid_namespace.h>
MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>");
MODULE_DESCRIPTION("Filesystem in Userspace");
MODULE_LICENSE("GPL");
MODULE_IMPORT_NS(ANDROID_GKI_VFS_EXPORT_ONLY);
static struct kmem_cache *fuse_inode_cachep;
struct list_head fuse_conn_list;
DEFINE_MUTEX(fuse_mutex);
static int set_global_limit(const char *val, const struct kernel_param *kp);
unsigned max_user_bgreq;
module_param_call(max_user_bgreq, set_global_limit, param_get_uint,
&max_user_bgreq, 0644);
__MODULE_PARM_TYPE(max_user_bgreq, "uint");
MODULE_PARM_DESC(max_user_bgreq,
"Global limit for the maximum number of backgrounded requests an "
"unprivileged user can set");
unsigned max_user_congthresh;
module_param_call(max_user_congthresh, set_global_limit, param_get_uint,
&max_user_congthresh, 0644);
__MODULE_PARM_TYPE(max_user_congthresh, "uint");
MODULE_PARM_DESC(max_user_congthresh,
"Global limit for the maximum congestion threshold an "
"unprivileged user can set");
#define FUSE_DEFAULT_BLKSIZE 512
/** Maximum number of outstanding background requests */
#define FUSE_DEFAULT_MAX_BACKGROUND 12
/** Congestion starts at 75% of maximum */
#define FUSE_DEFAULT_CONGESTION_THRESHOLD (FUSE_DEFAULT_MAX_BACKGROUND * 3 / 4)
#ifdef CONFIG_BLOCK
static struct file_system_type fuseblk_fs_type;
#endif
struct fuse_forget_link *fuse_alloc_forget(void)
{
return kzalloc(sizeof(struct fuse_forget_link), GFP_KERNEL_ACCOUNT);
}
static struct inode *fuse_alloc_inode(struct super_block *sb)
{
struct fuse_inode *fi;
fi = kmem_cache_alloc(fuse_inode_cachep, GFP_KERNEL);
if (!fi)
return NULL;
fi->i_time = 0;
fi->inval_mask = 0;
#ifdef CONFIG_FUSE_BPF
fi->backing_inode = NULL;
fi->bpf = NULL;
#endif
fi->nodeid = 0;
fi->nlookup = 0;
fi->attr_version = 0;
fi->orig_ino = 0;
fi->state = 0;
mutex_init(&fi->mutex);
spin_lock_init(&fi->lock);
fi->forget = fuse_alloc_forget();
if (!fi->forget)
goto out_free;
if (IS_ENABLED(CONFIG_FUSE_DAX) && !fuse_dax_inode_alloc(sb, fi))
goto out_free_forget;
return &fi->inode;
out_free_forget:
kfree(fi->forget);
out_free:
kmem_cache_free(fuse_inode_cachep, fi);
return NULL;
}
static void fuse_free_inode(struct inode *inode)
{
struct fuse_inode *fi = get_fuse_inode(inode);
mutex_destroy(&fi->mutex);
kfree(fi->forget);
#ifdef CONFIG_FUSE_DAX
kfree(fi->dax);
#endif
kmem_cache_free(fuse_inode_cachep, fi);
}
static void fuse_evict_inode(struct inode *inode)
{
struct fuse_inode *fi = get_fuse_inode(inode);
/* Will write inode on close/munmap and in all other dirtiers */
WARN_ON(inode->i_state & I_DIRTY_INODE);
#ifdef CONFIG_FUSE_BPF
iput(fi->backing_inode);
if (fi->bpf)
bpf_prog_put(fi->bpf);
fi->bpf = NULL;
#endif
truncate_inode_pages_final(&inode->i_data);
clear_inode(inode);
if (inode->i_sb->s_flags & SB_ACTIVE) {
struct fuse_conn *fc = get_fuse_conn(inode);
if (FUSE_IS_DAX(inode))
fuse_dax_inode_cleanup(inode);
if (fi->nlookup) {
fuse_queue_forget(fc, fi->forget, fi->nodeid,
fi->nlookup);
fi->forget = NULL;
}
}
if (S_ISREG(inode->i_mode) && !fuse_is_bad(inode)) {
WARN_ON(!list_empty(&fi->write_files));
WARN_ON(!list_empty(&fi->queued_writes));
}
}
static int fuse_reconfigure(struct fs_context *fsc)
{
struct super_block *sb = fsc->root->d_sb;
sync_filesystem(sb);
if (fsc->sb_flags & SB_MANDLOCK)
return -EINVAL;
return 0;
}
/*
* ino_t is 32-bits on 32-bit arch. We have to squash the 64-bit value down
* so that it will fit.
*/
static ino_t fuse_squash_ino(u64 ino64)
{
ino_t ino = (ino_t) ino64;
if (sizeof(ino_t) < sizeof(u64))
ino ^= ino64 >> (sizeof(u64) - sizeof(ino_t)) * 8;
return ino;
}
static void fuse_fill_attr_from_inode(struct fuse_attr *attr,
const struct inode *inode)
{
*attr = (struct fuse_attr){
.ino = inode->i_ino,
.size = inode->i_size,
.blocks = inode->i_blocks,
.atime = inode->i_atime.tv_sec,
.mtime = inode->i_mtime.tv_sec,
.ctime = inode->i_ctime.tv_sec,
.atimensec = inode->i_atime.tv_nsec,
.mtimensec = inode->i_mtime.tv_nsec,
.ctimensec = inode->i_ctime.tv_nsec,
.mode = inode->i_mode,
.nlink = inode->i_nlink,
.uid = inode->i_uid.val,
.gid = inode->i_gid.val,
.rdev = inode->i_rdev,
.blksize = 1u << inode->i_blkbits,
};
}
void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr,
u64 attr_valid)
{
struct fuse_conn *fc = get_fuse_conn(inode);
struct fuse_inode *fi = get_fuse_inode(inode);
lockdep_assert_held(&fi->lock);
fi->attr_version = atomic64_inc_return(&fc->attr_version);
fi->i_time = attr_valid;
WRITE_ONCE(fi->inval_mask, 0);
inode->i_ino = fuse_squash_ino(attr->ino);
inode->i_mode = (inode->i_mode & S_IFMT) | (attr->mode & 07777);
set_nlink(inode, attr->nlink);
inode->i_uid = make_kuid(fc->user_ns, attr->uid);
inode->i_gid = make_kgid(fc->user_ns, attr->gid);
inode->i_blocks = attr->blocks;
/* Sanitize nsecs */
attr->atimensec = min_t(u32, attr->atimensec, NSEC_PER_SEC - 1);
attr->mtimensec = min_t(u32, attr->mtimensec, NSEC_PER_SEC - 1);
attr->ctimensec = min_t(u32, attr->ctimensec, NSEC_PER_SEC - 1);
inode->i_atime.tv_sec = attr->atime;
inode->i_atime.tv_nsec = attr->atimensec;
/* mtime from server may be stale due to local buffered write */
if (!fc->writeback_cache || !S_ISREG(inode->i_mode)) {
inode->i_mtime.tv_sec = attr->mtime;
inode->i_mtime.tv_nsec = attr->mtimensec;
inode->i_ctime.tv_sec = attr->ctime;
inode->i_ctime.tv_nsec = attr->ctimensec;
}
if (attr->blksize != 0)
inode->i_blkbits = ilog2(attr->blksize);
else
inode->i_blkbits = inode->i_sb->s_blocksize_bits;
/*
* Don't set the sticky bit in i_mode, unless we want the VFS
* to check permissions. This prevents failures due to the
* check in may_delete().
*/
fi->orig_i_mode = inode->i_mode;
if (!fc->default_permissions)
inode->i_mode &= ~S_ISVTX;
fi->orig_ino = attr->ino;
/*
* We are refreshing inode data and it is possible that another
* client set suid/sgid or security.capability xattr. So clear
* S_NOSEC. Ideally, we could have cleared it only if suid/sgid
* was set or if security.capability xattr was set. But we don't
* know if security.capability has been set or not. So clear it
* anyway. Its less efficient but should be safe.
*/
inode->i_flags &= ~S_NOSEC;
}
void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,
u64 attr_valid, u64 attr_version)
{
struct fuse_conn *fc = get_fuse_conn(inode);
struct fuse_inode *fi = get_fuse_inode(inode);
bool is_wb = fc->writeback_cache;
loff_t oldsize;
struct timespec64 old_mtime;
spin_lock(&fi->lock);
if ((attr_version != 0 && fi->attr_version > attr_version) ||
test_bit(FUSE_I_SIZE_UNSTABLE, &fi->state)) {
spin_unlock(&fi->lock);
return;
}
old_mtime = inode->i_mtime;
fuse_change_attributes_common(inode, attr, attr_valid);
oldsize = inode->i_size;
/*
* In case of writeback_cache enabled, the cached writes beyond EOF
* extend local i_size without keeping userspace server in sync. So,
* attr->size coming from server can be stale. We cannot trust it.
*/
if (!is_wb || !S_ISREG(inode->i_mode))
i_size_write(inode, attr->size);
spin_unlock(&fi->lock);
if (!is_wb && S_ISREG(inode->i_mode)) {
bool inval = false;
if (oldsize != attr->size) {
truncate_pagecache(inode, attr->size);
if (!fc->explicit_inval_data)
inval = true;
} else if (fc->auto_inval_data) {
struct timespec64 new_mtime = {
.tv_sec = attr->mtime,
.tv_nsec = attr->mtimensec,
};
/*
* Auto inval mode also checks and invalidates if mtime
* has changed.
*/
if (!timespec64_equal(&old_mtime, &new_mtime))
inval = true;
}
if (inval)
invalidate_inode_pages2(inode->i_mapping);
}
}
static void fuse_init_inode(struct inode *inode, struct fuse_attr *attr)
{
inode->i_mode = attr->mode & S_IFMT;
inode->i_size = attr->size;
inode->i_mtime.tv_sec = attr->mtime;
inode->i_mtime.tv_nsec = attr->mtimensec;
inode->i_ctime.tv_sec = attr->ctime;
inode->i_ctime.tv_nsec = attr->ctimensec;
if (S_ISREG(inode->i_mode)) {
fuse_init_common(inode);
fuse_init_file_inode(inode);
} else if (S_ISDIR(inode->i_mode))
fuse_init_dir(inode);
else if (S_ISLNK(inode->i_mode))
fuse_init_symlink(inode);
else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
fuse_init_common(inode);
init_special_inode(inode, inode->i_mode, attr->rdev);
} else
BUG();
}
struct fuse_inode_identifier {
u64 nodeid;
struct inode *backing_inode;
};
static int fuse_inode_eq(struct inode *inode, void *_nodeidp)
{
struct fuse_inode_identifier *fii =
(struct fuse_inode_identifier *) _nodeidp;
struct fuse_inode *fi = get_fuse_inode(inode);
return fii->nodeid == fi->nodeid;
}
static int fuse_inode_backing_eq(struct inode *inode, void *_nodeidp)
{
struct fuse_inode_identifier *fii =
(struct fuse_inode_identifier *) _nodeidp;
struct fuse_inode *fi = get_fuse_inode(inode);
return fii->nodeid == fi->nodeid
#ifdef CONFIG_FUSE_BPF
&& fii->backing_inode == fi->backing_inode
#endif
;
}
static int fuse_inode_set(struct inode *inode, void *_nodeidp)
{
struct fuse_inode_identifier *fii =
(struct fuse_inode_identifier *) _nodeidp;
struct fuse_inode *fi = get_fuse_inode(inode);
fi->nodeid = fii->nodeid;
return 0;
}
static int fuse_inode_backing_set(struct inode *inode, void *_nodeidp)
{
struct fuse_inode_identifier *fii =
(struct fuse_inode_identifier *) _nodeidp;
struct fuse_inode *fi = get_fuse_inode(inode);
fi->nodeid = fii->nodeid;
#ifdef CONFIG_FUSE_BPF
fi->backing_inode = fii->backing_inode;
if (fi->backing_inode)
ihold(fi->backing_inode);
#endif
return 0;
}
struct inode *fuse_iget_backing(struct super_block *sb, u64 nodeid,
struct inode *backing_inode)
{
struct inode *inode;
struct fuse_inode *fi;
struct fuse_conn *fc = get_fuse_conn_super(sb);
struct fuse_inode_identifier fii = {
.nodeid = nodeid,
.backing_inode = backing_inode,
};
struct fuse_attr attr;
unsigned long hash = (unsigned long) backing_inode;
if (nodeid)
hash = nodeid;
fuse_fill_attr_from_inode(&attr, backing_inode);
inode = iget5_locked(sb, hash, fuse_inode_backing_eq,
fuse_inode_backing_set, &fii);
if (!inode)
return NULL;
if ((inode->i_state & I_NEW)) {
inode->i_flags |= S_NOATIME;
if (!fc->writeback_cache)
inode->i_flags |= S_NOCMTIME;
fuse_init_common(inode);
unlock_new_inode(inode);
}
fi = get_fuse_inode(inode);
fuse_init_inode(inode, &attr);
spin_lock(&fi->lock);
fi->nlookup++;
spin_unlock(&fi->lock);
return inode;
}
struct inode *fuse_iget(struct super_block *sb, u64 nodeid,
int generation, struct fuse_attr *attr,
u64 attr_valid, u64 attr_version)
{
struct inode *inode;
struct fuse_inode *fi;
struct fuse_conn *fc = get_fuse_conn_super(sb);
struct fuse_inode_identifier fii = {
.nodeid = nodeid,
};
/*
* Auto mount points get their node id from the submount root, which is
* not a unique identifier within this filesystem.
*
* To avoid conflicts, do not place submount points into the inode hash
* table.
*/
if (fc->auto_submounts && (attr->flags & FUSE_ATTR_SUBMOUNT) &&
S_ISDIR(attr->mode)) {
inode = new_inode(sb);
if (!inode)
return NULL;
fuse_init_inode(inode, attr);
get_fuse_inode(inode)->nodeid = nodeid;
inode->i_flags |= S_AUTOMOUNT;
goto done;
}
retry:
inode = iget5_locked(sb, nodeid, fuse_inode_eq, fuse_inode_set, &fii);
if (!inode)
return NULL;
if ((inode->i_state & I_NEW)) {
inode->i_flags |= S_NOATIME;
if (!fc->writeback_cache || !S_ISREG(attr->mode))
inode->i_flags |= S_NOCMTIME;
inode->i_generation = generation;
fuse_init_inode(inode, attr);
unlock_new_inode(inode);
} else if (fuse_stale_inode(inode, generation, attr)) {
/* nodeid was reused, any I/O on the old inode should fail */
fuse_make_bad(inode);
iput(inode);
goto retry;
}
done:
fi = get_fuse_inode(inode);
spin_lock(&fi->lock);
fi->nlookup++;
spin_unlock(&fi->lock);
fuse_change_attributes(inode, attr, attr_valid, attr_version);
return inode;
}
struct inode *fuse_ilookup(struct fuse_conn *fc, u64 nodeid,
struct fuse_mount **fm)
{
struct fuse_mount *fm_iter;
struct inode *inode;
struct fuse_inode_identifier fii = {
.nodeid = nodeid,
};
WARN_ON(!rwsem_is_locked(&fc->killsb));
list_for_each_entry(fm_iter, &fc->mounts, fc_entry) {
if (!fm_iter->sb)
continue;
inode = ilookup5(fm_iter->sb, nodeid, fuse_inode_eq, &fii);
if (inode) {
if (fm)
*fm = fm_iter;
return inode;
}
}
return NULL;
}
int fuse_reverse_inval_inode(struct fuse_conn *fc, u64 nodeid,
loff_t offset, loff_t len)
{
struct fuse_inode *fi;
struct inode *inode;
pgoff_t pg_start;
pgoff_t pg_end;
inode = fuse_ilookup(fc, nodeid, NULL);
if (!inode)
return -ENOENT;
fi = get_fuse_inode(inode);
spin_lock(&fi->lock);
fi->attr_version = atomic64_inc_return(&fc->attr_version);
spin_unlock(&fi->lock);
fuse_invalidate_attr(inode);
forget_all_cached_acls(inode);
if (offset >= 0) {
pg_start = offset >> PAGE_SHIFT;
if (len <= 0)
pg_end = -1;
else
pg_end = (offset + len - 1) >> PAGE_SHIFT;
invalidate_inode_pages2_range(inode->i_mapping,
pg_start, pg_end);
}
iput(inode);
return 0;
}
bool fuse_lock_inode(struct inode *inode)
{
bool locked = false;
if (!get_fuse_conn(inode)->parallel_dirops) {
mutex_lock(&get_fuse_inode(inode)->mutex);
locked = true;
}
return locked;
}
void fuse_unlock_inode(struct inode *inode, bool locked)
{
if (locked)
mutex_unlock(&get_fuse_inode(inode)->mutex);
}
static void fuse_umount_begin(struct super_block *sb)
{
struct fuse_conn *fc = get_fuse_conn_super(sb);
if (!fc->no_force_umount)
fuse_abort_conn(fc);
}
static void fuse_send_destroy(struct fuse_mount *fm)
{
if (fm->fc->conn_init) {
FUSE_ARGS(args);
args.opcode = FUSE_DESTROY;
args.force = true;
args.nocreds = true;
fuse_simple_request(fm, &args);
}
}
static int fuse_statfs(struct dentry *dentry, struct kstatfs *buf)
{
struct super_block *sb = dentry->d_sb;
struct fuse_mount *fm = get_fuse_mount_super(sb);
FUSE_ARGS(args);
struct fuse_statfs_out outarg;
int err;
#ifdef CONFIG_FUSE_BPF
struct fuse_err_ret fer;
#endif
if (!fuse_allow_current_process(fm->fc)) {
buf->f_type = FUSE_SUPER_MAGIC;
return 0;
}
#ifdef CONFIG_FUSE_BPF
fer = fuse_bpf_backing(dentry->d_inode, struct fuse_statfs_out,
fuse_statfs_initialize, fuse_statfs_backing,
fuse_statfs_finalize,
dentry, buf);
if (fer.ret)
return PTR_ERR(fer.result);
#endif
memset(&outarg, 0, sizeof(outarg));
args.in_numargs = 0;
args.opcode = FUSE_STATFS;
args.nodeid = get_node_id(d_inode(dentry));
args.out_numargs = 1;
args.out_args[0].size = sizeof(outarg);
args.out_args[0].value = &outarg;
err = fuse_simple_request(fm, &args);
if (!err)
convert_fuse_statfs(buf, &outarg.st);
return err;
}
static struct fuse_sync_bucket *fuse_sync_bucket_alloc(void)
{
struct fuse_sync_bucket *bucket;
bucket = kzalloc(sizeof(*bucket), GFP_KERNEL | __GFP_NOFAIL);
if (bucket) {
init_waitqueue_head(&bucket->waitq);
/* Initial active count */
atomic_set(&bucket->count, 1);
}
return bucket;
}
static void fuse_sync_fs_writes(struct fuse_conn *fc)
{
struct fuse_sync_bucket *bucket, *new_bucket;
int count;
new_bucket = fuse_sync_bucket_alloc();
spin_lock(&fc->lock);
bucket = rcu_dereference_protected(fc->curr_bucket, 1);
count = atomic_read(&bucket->count);
WARN_ON(count < 1);
/* No outstanding writes? */
if (count == 1) {
spin_unlock(&fc->lock);
kfree(new_bucket);
return;
}
/*
* Completion of new bucket depends on completion of this bucket, so add
* one more count.
*/
atomic_inc(&new_bucket->count);
rcu_assign_pointer(fc->curr_bucket, new_bucket);
spin_unlock(&fc->lock);
/*
* Drop initial active count. At this point if all writes in this and
* ancestor buckets complete, the count will go to zero and this task
* will be woken up.
*/
atomic_dec(&bucket->count);
wait_event(bucket->waitq, atomic_read(&bucket->count) == 0);
/* Drop temp count on descendant bucket */
fuse_sync_bucket_dec(new_bucket);
kfree_rcu(bucket, rcu);
}
static int fuse_sync_fs(struct super_block *sb, int wait)
{
struct fuse_mount *fm = get_fuse_mount_super(sb);
struct fuse_conn *fc = fm->fc;
struct fuse_syncfs_in inarg;
FUSE_ARGS(args);
int err;
/*
* Userspace cannot handle the wait == 0 case. Avoid a
* gratuitous roundtrip.
*/
if (!wait)
return 0;
/* The filesystem is being unmounted. Nothing to do. */
if (!sb->s_root)
return 0;
if (!fc->sync_fs)
return 0;
fuse_sync_fs_writes(fc);
memset(&inarg, 0, sizeof(inarg));
args.in_numargs = 1;
args.in_args[0].size = sizeof(inarg);
args.in_args[0].value = &inarg;
args.opcode = FUSE_SYNCFS;
args.nodeid = get_node_id(sb->s_root->d_inode);
args.out_numargs = 0;
err = fuse_simple_request(fm, &args);
if (err == -ENOSYS) {
fc->sync_fs = 0;
err = 0;
}
return err;
}
enum {
OPT_SOURCE,
OPT_SUBTYPE,
OPT_FD,
OPT_ROOTMODE,
OPT_USER_ID,
OPT_GROUP_ID,
OPT_DEFAULT_PERMISSIONS,
OPT_ALLOW_OTHER,
OPT_MAX_READ,
OPT_BLKSIZE,
OPT_ROOT_BPF,
OPT_ROOT_DIR,
OPT_NO_DAEMON,
OPT_ERR
};
static const struct fs_parameter_spec fuse_fs_parameters[] = {
fsparam_string ("source", OPT_SOURCE),
fsparam_u32 ("fd", OPT_FD),
fsparam_u32oct ("rootmode", OPT_ROOTMODE),
fsparam_u32 ("user_id", OPT_USER_ID),
fsparam_u32 ("group_id", OPT_GROUP_ID),
fsparam_flag ("default_permissions", OPT_DEFAULT_PERMISSIONS),
fsparam_flag ("allow_other", OPT_ALLOW_OTHER),
fsparam_u32 ("max_read", OPT_MAX_READ),
fsparam_u32 ("blksize", OPT_BLKSIZE),
fsparam_string ("subtype", OPT_SUBTYPE),
fsparam_u32 ("root_bpf", OPT_ROOT_BPF),
fsparam_u32 ("root_dir", OPT_ROOT_DIR),
fsparam_flag ("no_daemon", OPT_NO_DAEMON),
{}
};
static int fuse_parse_param(struct fs_context *fsc, struct fs_parameter *param)
{
struct fs_parse_result result;
struct fuse_fs_context *ctx = fsc->fs_private;
int opt;
if (fsc->purpose == FS_CONTEXT_FOR_RECONFIGURE) {
/*
* Ignore options coming from mount(MS_REMOUNT) for backward
* compatibility.
*/
if (fsc->oldapi)
return 0;
return invalfc(fsc, "No changes allowed in reconfigure");
}
opt = fs_parse(fsc, fuse_fs_parameters, param, &result);
if (opt < 0)
return opt;
switch (opt) {
case OPT_SOURCE:
if (fsc->source)
return invalfc(fsc, "Multiple sources specified");
fsc->source = param->string;
param->string = NULL;
break;
case OPT_SUBTYPE:
if (ctx->subtype)
return invalfc(fsc, "Multiple subtypes specified");
ctx->subtype = param->string;
param->string = NULL;
return 0;
case OPT_FD:
ctx->fd = result.uint_32;
ctx->fd_present = true;
break;
case OPT_ROOTMODE:
if (!fuse_valid_type(result.uint_32))
return invalfc(fsc, "Invalid rootmode");
ctx->rootmode = result.uint_32;
ctx->rootmode_present = true;
break;
case OPT_USER_ID:
ctx->user_id = make_kuid(fsc->user_ns, result.uint_32);
if (!uid_valid(ctx->user_id))
return invalfc(fsc, "Invalid user_id");
ctx->user_id_present = true;
break;
case OPT_GROUP_ID:
ctx->group_id = make_kgid(fsc->user_ns, result.uint_32);
if (!gid_valid(ctx->group_id))
return invalfc(fsc, "Invalid group_id");
ctx->group_id_present = true;
break;
case OPT_DEFAULT_PERMISSIONS:
ctx->default_permissions = true;
break;
case OPT_ALLOW_OTHER:
ctx->allow_other = true;
break;
case OPT_MAX_READ:
ctx->max_read = result.uint_32;
break;
case OPT_BLKSIZE:
if (!ctx->is_bdev)
return invalfc(fsc, "blksize only supported for fuseblk");
ctx->blksize = result.uint_32;
break;
case OPT_ROOT_BPF:
ctx->root_bpf = bpf_prog_get_type_dev(result.uint_32,
BPF_PROG_TYPE_FUSE, false);
if (IS_ERR(ctx->root_bpf)) {
ctx->root_bpf = NULL;
return invalfc(fsc, "Unable to open bpf program");
}
break;
case OPT_ROOT_DIR:
ctx->root_dir = fget(result.uint_32);
if (!ctx->root_dir)
return invalfc(fsc, "Unable to open root directory");
break;
case OPT_NO_DAEMON:
ctx->no_daemon = true;
ctx->fd_present = true;
break;
default:
return -EINVAL;
}
return 0;
}
static void fuse_free_fsc(struct fs_context *fsc)
{
struct fuse_fs_context *ctx = fsc->fs_private;
if (ctx) {
if (ctx->root_dir)
fput(ctx->root_dir);
if (ctx->root_bpf)
bpf_prog_put(ctx->root_bpf);
kfree(ctx->subtype);
kfree(ctx);
}
}
static int fuse_show_options(struct seq_file *m, struct dentry *root)
{
struct super_block *sb = root->d_sb;
struct fuse_conn *fc = get_fuse_conn_super(sb);
if (fc->legacy_opts_show) {
seq_printf(m, ",user_id=%u",
from_kuid_munged(fc->user_ns, fc->user_id));
seq_printf(m, ",group_id=%u",
from_kgid_munged(fc->user_ns, fc->group_id));
if (fc->default_permissions)
seq_puts(m, ",default_permissions");
if (fc->allow_other)
seq_puts(m, ",allow_other");
if (fc->max_read != ~0)
seq_printf(m, ",max_read=%u", fc->max_read);
if (sb->s_bdev && sb->s_blocksize != FUSE_DEFAULT_BLKSIZE)
seq_printf(m, ",blksize=%lu", sb->s_blocksize);
}
#ifdef CONFIG_FUSE_DAX
if (fc->dax)
seq_puts(m, ",dax");
#endif
return 0;
}
static void fuse_iqueue_init(struct fuse_iqueue *fiq,
const struct fuse_iqueue_ops *ops,
void *priv)
{
memset(fiq, 0, sizeof(struct fuse_iqueue));
spin_lock_init(&fiq->lock);
init_waitqueue_head(&fiq->waitq);
INIT_LIST_HEAD(&fiq->pending);
INIT_LIST_HEAD(&fiq->interrupts);
fiq->forget_list_tail = &fiq->forget_list_head;
fiq->connected = 1;
fiq->ops = ops;
fiq->priv = priv;
}
static void fuse_pqueue_init(struct fuse_pqueue *fpq)
{
unsigned int i;
spin_lock_init(&fpq->lock);
for (i = 0; i < FUSE_PQ_HASH_SIZE; i++)
INIT_LIST_HEAD(&fpq->processing[i]);
INIT_LIST_HEAD(&fpq->io);
fpq->connected = 1;
}
void fuse_conn_init(struct fuse_conn *fc, struct fuse_mount *fm,
struct user_namespace *user_ns,
const struct fuse_iqueue_ops *fiq_ops, void *fiq_priv)
{
memset(fc, 0, sizeof(*fc));
spin_lock_init(&fc->lock);
spin_lock_init(&fc->bg_lock);
spin_lock_init(&fc->passthrough_req_lock);
init_rwsem(&fc->killsb);
refcount_set(&fc->count, 1);
atomic_set(&fc->dev_count, 1);
init_waitqueue_head(&fc->blocked_waitq);
fuse_iqueue_init(&fc->iq, fiq_ops, fiq_priv);
INIT_LIST_HEAD(&fc->bg_queue);
INIT_LIST_HEAD(&fc->entry);
INIT_LIST_HEAD(&fc->devices);
idr_init(&fc->passthrough_req);
atomic_set(&fc->num_waiting, 0);
fc->max_background = FUSE_DEFAULT_MAX_BACKGROUND;
fc->congestion_threshold = FUSE_DEFAULT_CONGESTION_THRESHOLD;
atomic64_set(&fc->khctr, 0);
fc->polled_files = RB_ROOT;
fc->blocked = 0;
fc->initialized = 0;
fc->connected = 1;
atomic64_set(&fc->attr_version, 1);
get_random_bytes(&fc->scramble_key, sizeof(fc->scramble_key));
fc->pid_ns = get_pid_ns(task_active_pid_ns(current));
fc->user_ns = get_user_ns(user_ns);
fc->max_pages = FUSE_DEFAULT_MAX_PAGES_PER_REQ;
fc->max_pages_limit = FUSE_MAX_MAX_PAGES;
INIT_LIST_HEAD(&fc->mounts);
list_add(&fm->fc_entry, &fc->mounts);
fm->fc = fc;
}
EXPORT_SYMBOL_GPL(fuse_conn_init);
void fuse_conn_put(struct fuse_conn *fc)
{
if (refcount_dec_and_test(&fc->count)) {
struct fuse_iqueue *fiq = &fc->iq;
struct fuse_sync_bucket *bucket;
if (IS_ENABLED(CONFIG_FUSE_DAX))
fuse_dax_conn_free(fc);
if (fiq->ops->release)
fiq->ops->release(fiq);
put_pid_ns(fc->pid_ns);
put_user_ns(fc->user_ns);
bucket = rcu_dereference_protected(fc->curr_bucket, 1);
if (bucket) {
WARN_ON(atomic_read(&bucket->count) != 1);
kfree(bucket);
}
fc->release(fc);
}
}
EXPORT_SYMBOL_GPL(fuse_conn_put);
struct fuse_conn *fuse_conn_get(struct fuse_conn *fc)
{
refcount_inc(&fc->count);
return fc;
}
EXPORT_SYMBOL_GPL(fuse_conn_get);
static struct inode *fuse_get_root_inode(struct super_block *sb,
unsigned int mode,
struct bpf_prog *root_bpf,
struct file *backing_fd)
{
struct fuse_attr attr;
struct inode *inode;
memset(&attr, 0, sizeof(attr));
attr.mode = mode;
attr.ino = FUSE_ROOT_ID;
attr.nlink = 1;
inode = fuse_iget(sb, 1, 0, &attr, 0, 0);
if (!inode)
return NULL;
#ifdef CONFIG_FUSE_BPF
get_fuse_inode(inode)->bpf = root_bpf;
if (root_bpf)
bpf_prog_inc(root_bpf);
if (backing_fd) {
get_fuse_inode(inode)->backing_inode = backing_fd->f_inode;
ihold(backing_fd->f_inode);
}
#endif
return inode;
}
struct fuse_inode_handle {
u64 nodeid;
u32 generation;
};
static struct dentry *fuse_get_dentry(struct super_block *sb,
struct fuse_inode_handle *handle)
{
struct fuse_conn *fc = get_fuse_conn_super(sb);
struct inode *inode;
struct dentry *entry;
int err = -ESTALE;
struct fuse_inode_identifier fii = {
.nodeid = handle->nodeid,
};
if (handle->nodeid == 0)
goto out_err;
inode = ilookup5(sb, handle->nodeid, fuse_inode_eq, &fii);
if (!inode) {
struct fuse_entry_out outarg;
const struct qstr name = QSTR_INIT(".", 1);
if (!fc->export_support)
goto out_err;
err = fuse_lookup_name(sb, handle->nodeid, &name, &outarg,
NULL, &inode);
if (err && err != -ENOENT)
goto out_err;
if (err || !inode) {
err = -ESTALE;
goto out_err;
}
err = -EIO;
if (get_node_id(inode) != handle->nodeid)
goto out_iput;
}
err = -ESTALE;
if (inode->i_generation != handle->generation)
goto out_iput;
entry = d_obtain_alias(inode);
if (!IS_ERR(entry) && get_node_id(inode) != FUSE_ROOT_ID)
fuse_invalidate_entry_cache(entry);
return entry;
out_iput:
iput(inode);
out_err:
return ERR_PTR(err);
}
static int fuse_encode_fh(struct inode *inode, u32 *fh, int *max_len,
struct inode *parent)
{
int len = parent ? 6 : 3;
u64 nodeid;
u32 generation;
if (*max_len < len) {
*max_len = len;
return FILEID_INVALID;
}
nodeid = get_fuse_inode(inode)->nodeid;
generation = inode->i_generation;
fh[0] = (u32)(nodeid >> 32);
fh[1] = (u32)(nodeid & 0xffffffff);
fh[2] = generation;
if (parent) {
nodeid = get_fuse_inode(parent)->nodeid;
generation = parent->i_generation;
fh[3] = (u32)(nodeid >> 32);
fh[4] = (u32)(nodeid & 0xffffffff);
fh[5] = generation;
}
*max_len = len;
return parent ? 0x82 : 0x81;
}
static struct dentry *fuse_fh_to_dentry(struct super_block *sb,
struct fid *fid, int fh_len, int fh_type)
{
struct fuse_inode_handle handle;
if ((fh_type != 0x81 && fh_type != 0x82) || fh_len < 3)
return NULL;
handle.nodeid = (u64) fid->raw[0] << 32;
handle.nodeid |= (u64) fid->raw[1];
handle.generation = fid->raw[2];
return fuse_get_dentry(sb, &handle);
}
static struct dentry *fuse_fh_to_parent(struct super_block *sb,
struct fid *fid, int fh_len, int fh_type)
{
struct fuse_inode_handle parent;
if (fh_type != 0x82 || fh_len < 6)
return NULL;
parent.nodeid = (u64) fid->raw[3] << 32;
parent.nodeid |= (u64) fid->raw[4];
parent.generation = fid->raw[5];
return fuse_get_dentry(sb, &parent);
}
static struct dentry *fuse_get_parent(struct dentry *child)
{
struct inode *child_inode = d_inode(child);
struct fuse_conn *fc = get_fuse_conn(child_inode);
struct inode *inode;
struct dentry *parent;
struct fuse_entry_out outarg;
const struct qstr name = QSTR_INIT("..", 2);
int err;
if (!fc->export_support)
return ERR_PTR(-ESTALE);
err = fuse_lookup_name(child_inode->i_sb, get_node_id(child_inode),
&name, &outarg, NULL, &inode);
if (err) {
if (err == -ENOENT)
return ERR_PTR(-ESTALE);
return ERR_PTR(err);
}
parent = d_obtain_alias(inode);
if (!IS_ERR(parent) && get_node_id(inode) != FUSE_ROOT_ID)
fuse_invalidate_entry_cache(parent);
return parent;
}
static const struct export_operations fuse_export_operations = {
.fh_to_dentry = fuse_fh_to_dentry,
.fh_to_parent = fuse_fh_to_parent,
.encode_fh = fuse_encode_fh,
.get_parent = fuse_get_parent,
};
static const struct super_operations fuse_super_operations = {
.alloc_inode = fuse_alloc_inode,
.free_inode = fuse_free_inode,
.evict_inode = fuse_evict_inode,
.write_inode = fuse_write_inode,
.drop_inode = generic_delete_inode,
.umount_begin = fuse_umount_begin,
.statfs = fuse_statfs,
.sync_fs = fuse_sync_fs,
.show_options = fuse_show_options,
};
static void sanitize_global_limit(unsigned *limit)
{
/*
* The default maximum number of async requests is calculated to consume
* 1/2^13 of the total memory, assuming 392 bytes per request.
*/
if (*limit == 0)
*limit = ((totalram_pages() << PAGE_SHIFT) >> 13) / 392;
if (*limit >= 1 << 16)
*limit = (1 << 16) - 1;
}
static int set_global_limit(const char *val, const struct kernel_param *kp)
{
int rv;
rv = param_set_uint(val, kp);
if (rv)
return rv;
sanitize_global_limit((unsigned *)kp->arg);
return 0;
}
static void process_init_limits(struct fuse_conn *fc, struct fuse_init_out *arg)
{
int cap_sys_admin = capable(CAP_SYS_ADMIN);
if (arg->minor < 13)
return;
sanitize_global_limit(&max_user_bgreq);
sanitize_global_limit(&max_user_congthresh);
spin_lock(&fc->bg_lock);
if (arg->max_background) {
fc->max_background = arg->max_background;
if (!cap_sys_admin && fc->max_background > max_user_bgreq)
fc->max_background = max_user_bgreq;
}
if (arg->congestion_threshold) {
fc->congestion_threshold = arg->congestion_threshold;
if (!cap_sys_admin &&
fc->congestion_threshold > max_user_congthresh)
fc->congestion_threshold = max_user_congthresh;
}
spin_unlock(&fc->bg_lock);
}
struct fuse_init_args {
struct fuse_args args;
struct fuse_init_in in;
struct fuse_init_out out;
};
static void process_init_reply(struct fuse_mount *fm, struct fuse_args *args,
int error)
{
struct fuse_conn *fc = fm->fc;
struct fuse_init_args *ia = container_of(args, typeof(*ia), args);
struct fuse_init_out *arg = &ia->out;
bool ok = true;
if (error || arg->major != FUSE_KERNEL_VERSION)
ok = false;
else {
unsigned long ra_pages;
process_init_limits(fc, arg);
if (arg->minor >= 6) {
u64 flags = arg->flags | (u64) arg->flags2 << 32;
ra_pages = arg->max_readahead / PAGE_SIZE;
if (flags & FUSE_ASYNC_READ)
fc->async_read = 1;
if (!(flags & FUSE_POSIX_LOCKS))
fc->no_lock = 1;
if (arg->minor >= 17) {
if (!(flags & FUSE_FLOCK_LOCKS))
fc->no_flock = 1;
} else {
if (!(flags & FUSE_POSIX_LOCKS))
fc->no_flock = 1;
}
if (flags & FUSE_ATOMIC_O_TRUNC)
fc->atomic_o_trunc = 1;
if (arg->minor >= 9) {
/* LOOKUP has dependency on proto version */
if (flags & FUSE_EXPORT_SUPPORT)
fc->export_support = 1;
}
if (flags & FUSE_BIG_WRITES)
fc->big_writes = 1;
if (flags & FUSE_DONT_MASK)
fc->dont_mask = 1;
if (flags & FUSE_AUTO_INVAL_DATA)
fc->auto_inval_data = 1;
else if (flags & FUSE_EXPLICIT_INVAL_DATA)
fc->explicit_inval_data = 1;
if (flags & FUSE_DO_READDIRPLUS) {
fc->do_readdirplus = 1;
if (flags & FUSE_READDIRPLUS_AUTO)
fc->readdirplus_auto = 1;
}
if (flags & FUSE_ASYNC_DIO)
fc->async_dio = 1;
if (flags & FUSE_WRITEBACK_CACHE)
fc->writeback_cache = 1;
if (flags & FUSE_PARALLEL_DIROPS)
fc->parallel_dirops = 1;
if (flags & FUSE_HANDLE_KILLPRIV)
fc->handle_killpriv = 1;
if (arg->time_gran && arg->time_gran <= 1000000000)
fm->sb->s_time_gran = arg->time_gran;
if ((flags & FUSE_POSIX_ACL)) {
fc->default_permissions = 1;
fc->posix_acl = 1;
fm->sb->s_xattr = fuse_acl_xattr_handlers;
}
if (flags & FUSE_CACHE_SYMLINKS)
fc->cache_symlinks = 1;
if (flags & FUSE_ABORT_ERROR)
fc->abort_err = 1;
if (flags & FUSE_MAX_PAGES) {
fc->max_pages =
min_t(unsigned int, fc->max_pages_limit,
max_t(unsigned int, arg->max_pages, 1));
}
if (IS_ENABLED(CONFIG_FUSE_DAX) &&
flags & FUSE_MAP_ALIGNMENT &&
!fuse_dax_check_alignment(fc, arg->map_alignment)) {
ok = false;
}
if (flags & FUSE_HANDLE_KILLPRIV_V2) {
fc->handle_killpriv_v2 = 1;
fm->sb->s_flags |= SB_NOSEC;
}
if (flags & FUSE_PASSTHROUGH) {
fc->passthrough = 1;
/* Prevent further stacking */
fm->sb->s_stack_depth =
FILESYSTEM_MAX_STACK_DEPTH;
}
if (flags & FUSE_SETXATTR_EXT)
fc->setxattr_ext = 1;
if (flags & FUSE_SECURITY_CTX)
fc->init_security = 1;
} else {
ra_pages = fc->max_read / PAGE_SIZE;
fc->no_lock = 1;
fc->no_flock = 1;
}
fm->sb->s_bdi->ra_pages =
min(fm->sb->s_bdi->ra_pages, ra_pages);
fc->minor = arg->minor;
fc->max_write = arg->minor < 5 ? 4096 : arg->max_write;
fc->max_write = max_t(unsigned, 4096, fc->max_write);
fc->conn_init = 1;
}
kfree(ia);
if (!ok) {
fc->conn_init = 0;
fc->conn_error = 1;
}
fuse_set_initialized(fc);
wake_up_all(&fc->blocked_waitq);
}
void fuse_send_init(struct fuse_mount *fm)
{
struct fuse_init_args *ia;
u64 flags;
ia = kzalloc(sizeof(*ia), GFP_KERNEL | __GFP_NOFAIL);
ia->in.major = FUSE_KERNEL_VERSION;
ia->in.minor = FUSE_KERNEL_MINOR_VERSION;
ia->in.max_readahead = fm->sb->s_bdi->ra_pages * PAGE_SIZE;
flags =
FUSE_ASYNC_READ | FUSE_POSIX_LOCKS | FUSE_ATOMIC_O_TRUNC |
FUSE_EXPORT_SUPPORT | FUSE_BIG_WRITES | FUSE_DONT_MASK |
FUSE_SPLICE_WRITE | FUSE_SPLICE_MOVE | FUSE_SPLICE_READ |
FUSE_FLOCK_LOCKS | FUSE_HAS_IOCTL_DIR | FUSE_AUTO_INVAL_DATA |
FUSE_DO_READDIRPLUS | FUSE_READDIRPLUS_AUTO | FUSE_ASYNC_DIO |
FUSE_WRITEBACK_CACHE | FUSE_NO_OPEN_SUPPORT |
FUSE_PARALLEL_DIROPS | FUSE_HANDLE_KILLPRIV | FUSE_POSIX_ACL |
FUSE_ABORT_ERROR | FUSE_MAX_PAGES | FUSE_CACHE_SYMLINKS |
FUSE_NO_OPENDIR_SUPPORT | FUSE_EXPLICIT_INVAL_DATA |
FUSE_PASSTHROUGH |
FUSE_HANDLE_KILLPRIV_V2 | FUSE_SETXATTR_EXT | FUSE_INIT_EXT |
FUSE_SECURITY_CTX;
#ifdef CONFIG_FUSE_DAX
if (fm->fc->dax)
flags |= FUSE_MAP_ALIGNMENT;
#endif
if (fm->fc->auto_submounts)
flags |= FUSE_SUBMOUNTS;
ia->in.flags = flags;
ia->in.flags2 = flags >> 32;
ia->args.opcode = FUSE_INIT;
ia->args.in_numargs = 1;
ia->args.in_args[0].size = sizeof(ia->in);
ia->args.in_args[0].value = &ia->in;
ia->args.out_numargs = 1;
/* Variable length argument used for backward compatibility
with interface version < 7.5. Rest of init_out is zeroed
by do_get_request(), so a short reply is not a problem */
ia->args.out_argvar = true;
ia->args.out_args[0].size = sizeof(ia->out);
ia->args.out_args[0].value = &ia->out;
ia->args.force = true;
ia->args.nocreds = true;
ia->args.end = process_init_reply;
if (unlikely(fm->fc->no_daemon) || fuse_simple_background(fm, &ia->args, GFP_KERNEL) != 0)
process_init_reply(fm, &ia->args, -ENOTCONN);
}
EXPORT_SYMBOL_GPL(fuse_send_init);
static int free_fuse_passthrough(int id, void *p, void *data)
{
struct fuse_passthrough *passthrough = (struct fuse_passthrough *)p;
fuse_passthrough_release(passthrough);
kfree(p);
return 0;
}
void fuse_free_conn(struct fuse_conn *fc)
{
WARN_ON(!list_empty(&fc->devices));
idr_for_each(&fc->passthrough_req, free_fuse_passthrough, NULL);
idr_destroy(&fc->passthrough_req);
kfree_rcu(fc, rcu);
}
EXPORT_SYMBOL_GPL(fuse_free_conn);
static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb)
{
int err;
char *suffix = "";
if (sb->s_bdev) {
suffix = "-fuseblk";
/*
* sb->s_bdi points to blkdev's bdi however we want to redirect
* it to our private bdi...
*/
bdi_put(sb->s_bdi);
sb->s_bdi = &noop_backing_dev_info;
}
err = super_setup_bdi_name(sb, "%u:%u%s", MAJOR(fc->dev),
MINOR(fc->dev), suffix);
if (err)
return err;
/* fuse does it's own writeback accounting */
sb->s_bdi->capabilities &= ~BDI_CAP_WRITEBACK_ACCT;
sb->s_bdi->capabilities |= BDI_CAP_STRICTLIMIT;
/*
* For a single fuse filesystem use max 1% of dirty +
* writeback threshold.
*
* This gives about 1M of write buffer for memory maps on a
* machine with 1G and 10% dirty_ratio, which should be more
* than enough.
*
* Privileged users can raise it by writing to
*
* /sys/class/bdi/<bdi>/max_ratio
*/
bdi_set_max_ratio(sb->s_bdi, 1);
return 0;
}
struct fuse_dev *fuse_dev_alloc(void)
{
struct fuse_dev *fud;
struct list_head *pq;
fud = kzalloc(sizeof(struct fuse_dev), GFP_KERNEL);
if (!fud)
return NULL;
pq = kcalloc(FUSE_PQ_HASH_SIZE, sizeof(struct list_head), GFP_KERNEL);
if (!pq) {
kfree(fud);
return NULL;
}
fud->pq.processing = pq;
fuse_pqueue_init(&fud->pq);
return fud;
}
EXPORT_SYMBOL_GPL(fuse_dev_alloc);
void fuse_dev_install(struct fuse_dev *fud, struct fuse_conn *fc)
{
fud->fc = fuse_conn_get(fc);
spin_lock(&fc->lock);
list_add_tail(&fud->entry, &fc->devices);
spin_unlock(&fc->lock);
}
EXPORT_SYMBOL_GPL(fuse_dev_install);
struct fuse_dev *fuse_dev_alloc_install(struct fuse_conn *fc)
{
struct fuse_dev *fud;
fud = fuse_dev_alloc();
if (!fud)
return NULL;
fuse_dev_install(fud, fc);
return fud;
}
EXPORT_SYMBOL_GPL(fuse_dev_alloc_install);
void fuse_dev_free(struct fuse_dev *fud)
{
struct fuse_conn *fc = fud->fc;
if (fc) {
spin_lock(&fc->lock);
list_del(&fud->entry);
spin_unlock(&fc->lock);
fuse_conn_put(fc);
}
kfree(fud->pq.processing);
kfree(fud);
}
EXPORT_SYMBOL_GPL(fuse_dev_free);
static void fuse_sb_defaults(struct super_block *sb)
{
sb->s_magic = FUSE_SUPER_MAGIC;
sb->s_op = &fuse_super_operations;
sb->s_xattr = fuse_xattr_handlers;
sb->s_maxbytes = MAX_LFS_FILESIZE;
sb->s_time_gran = 1;
sb->s_export_op = &fuse_export_operations;
sb->s_iflags |= SB_I_IMA_UNVERIFIABLE_SIGNATURE;
if (sb->s_user_ns != &init_user_ns)
sb->s_iflags |= SB_I_UNTRUSTED_MOUNTER;
sb->s_flags &= ~(SB_NOSEC | SB_I_VERSION);
/*
* If we are not in the initial user namespace posix
* acls must be translated.
*/
if (sb->s_user_ns != &init_user_ns)
sb->s_xattr = fuse_no_acl_xattr_handlers;
}
static int fuse_fill_super_submount(struct super_block *sb,
struct fuse_inode *parent_fi)
{
struct fuse_mount *fm = get_fuse_mount_super(sb);
struct super_block *parent_sb = parent_fi->inode.i_sb;
struct fuse_attr root_attr;
struct inode *root;
fuse_sb_defaults(sb);
fm->sb = sb;
WARN_ON(sb->s_bdi != &noop_backing_dev_info);
sb->s_bdi = bdi_get(parent_sb->s_bdi);
sb->s_xattr = parent_sb->s_xattr;
sb->s_time_gran = parent_sb->s_time_gran;
sb->s_blocksize = parent_sb->s_blocksize;
sb->s_blocksize_bits = parent_sb->s_blocksize_bits;
sb->s_subtype = kstrdup(parent_sb->s_subtype, GFP_KERNEL);
if (parent_sb->s_subtype && !sb->s_subtype)
return -ENOMEM;
fuse_fill_attr_from_inode(&root_attr, &parent_fi->inode);
root = fuse_iget(sb, parent_fi->nodeid, 0, &root_attr, 0, 0);
/*
* This inode is just a duplicate, so it is not looked up and
* its nlookup should not be incremented. fuse_iget() does
* that, though, so undo it here.
*/
get_fuse_inode(root)->nlookup--;
sb->s_d_op = &fuse_dentry_operations;
sb->s_root = d_make_root(root);
if (!sb->s_root)
return -ENOMEM;
return 0;
}
/* Filesystem context private data holds the FUSE inode of the mount point */
static int fuse_get_tree_submount(struct fs_context *fsc)
{
struct fuse_mount *fm;
struct fuse_inode *mp_fi = fsc->fs_private;
struct fuse_conn *fc = get_fuse_conn(&mp_fi->inode);
struct super_block *sb;
int err;
fm = kzalloc(sizeof(struct fuse_mount), GFP_KERNEL);
if (!fm)
return -ENOMEM;
fm->fc = fuse_conn_get(fc);
fsc->s_fs_info = fm;
sb = sget_fc(fsc, NULL, set_anon_super_fc);
if (fsc->s_fs_info)
fuse_mount_destroy(fm);
if (IS_ERR(sb))
return PTR_ERR(sb);
/* Initialize superblock, making @mp_fi its root */
err = fuse_fill_super_submount(sb, mp_fi);
if (err) {
deactivate_locked_super(sb);
return err;
}
down_write(&fc->killsb);
list_add_tail(&fm->fc_entry, &fc->mounts);
up_write(&fc->killsb);
sb->s_flags |= SB_ACTIVE;
fsc->root = dget(sb->s_root);
return 0;
}
static const struct fs_context_operations fuse_context_submount_ops = {
.get_tree = fuse_get_tree_submount,
};
int fuse_init_fs_context_submount(struct fs_context *fsc)
{
fsc->ops = &fuse_context_submount_ops;
return 0;
}
EXPORT_SYMBOL_GPL(fuse_init_fs_context_submount);
int fuse_fill_super_common(struct super_block *sb, struct fuse_fs_context *ctx)
{
struct fuse_dev *fud = NULL;
struct fuse_mount *fm = get_fuse_mount_super(sb);
struct fuse_conn *fc = fm->fc;
struct inode *root;
struct dentry *root_dentry;
int err;
err = -EINVAL;
if (sb->s_flags & SB_MANDLOCK)
goto err;
rcu_assign_pointer(fc->curr_bucket, fuse_sync_bucket_alloc());
fuse_sb_defaults(sb);
if (ctx->is_bdev) {
#ifdef CONFIG_BLOCK
err = -EINVAL;
if (!sb_set_blocksize(sb, ctx->blksize))
goto err;
#endif
} else {
sb->s_blocksize = PAGE_SIZE;
sb->s_blocksize_bits = PAGE_SHIFT;
}
sb->s_subtype = ctx->subtype;
ctx->subtype = NULL;
if (IS_ENABLED(CONFIG_FUSE_DAX)) {
err = fuse_dax_conn_alloc(fc, ctx->dax_dev);
if (err)
goto err;
}
if (ctx->fudptr) {
err = -ENOMEM;
fud = fuse_dev_alloc_install(fc);
if (!fud)
goto err_free_dax;
}
fc->dev = sb->s_dev;
fm->sb = sb;
err = fuse_bdi_init(fc, sb);
if (err)
goto err_dev_free;
/* Handle umasking inside the fuse code */
if (sb->s_flags & SB_POSIXACL)
fc->dont_mask = 1;
sb->s_flags |= SB_POSIXACL;
fc->default_permissions = ctx->default_permissions;
fc->allow_other = ctx->allow_other;
fc->user_id = ctx->user_id;
fc->group_id = ctx->group_id;
fc->legacy_opts_show = ctx->legacy_opts_show;
fc->max_read = max_t(unsigned int, 4096, ctx->max_read);
fc->destroy = ctx->destroy;
fc->no_control = ctx->no_control;
fc->no_force_umount = ctx->no_force_umount;
fc->no_daemon = ctx->no_daemon;
err = -ENOMEM;
root = fuse_get_root_inode(sb, ctx->rootmode, ctx->root_bpf,
ctx->root_dir);
sb->s_d_op = &fuse_root_dentry_operations;
root_dentry = d_make_root(root);
if (!root_dentry)
goto err_dev_free;
fuse_init_dentry_root(root_dentry, ctx->root_dir);
/* Root dentry doesn't have .d_revalidate */
sb->s_d_op = &fuse_dentry_operations;
mutex_lock(&fuse_mutex);
err = -EINVAL;
if (ctx->fudptr && *ctx->fudptr)
goto err_unlock;
err = fuse_ctl_add_conn(fc);
if (err)
goto err_unlock;
list_add_tail(&fc->entry, &fuse_conn_list);
sb->s_root = root_dentry;
if (ctx->fudptr)
*ctx->fudptr = fud;
mutex_unlock(&fuse_mutex);
return 0;
err_unlock:
mutex_unlock(&fuse_mutex);
dput(root_dentry);
err_dev_free:
if (fud)
fuse_dev_free(fud);
err_free_dax:
if (IS_ENABLED(CONFIG_FUSE_DAX))
fuse_dax_conn_free(fc);
err:
return err;
}
EXPORT_SYMBOL_GPL(fuse_fill_super_common);
static int fuse_fill_super(struct super_block *sb, struct fs_context *fsc)
{
struct fuse_fs_context *ctx = fsc->fs_private;
int err;
if (!ctx->no_daemon) {
if (!ctx->file || !ctx->rootmode_present ||
!ctx->user_id_present || !ctx->group_id_present)
return -EINVAL;
/*
* Require mount to happen from the same user namespace which
* opened /dev/fuse to prevent potential attacks.
*/
if ((ctx->file->f_op != &fuse_dev_operations) ||
(ctx->file->f_cred->user_ns != sb->s_user_ns))
return -EINVAL;
ctx->fudptr = &ctx->file->private_data;
}
err = fuse_fill_super_common(sb, ctx);
if (err)
return err;
/* file->private_data shall be visible on all CPUs after this */
smp_mb();
fuse_send_init(get_fuse_mount_super(sb));
return 0;
}
/*
* This is the path where user supplied an already initialized fuse dev. In
* this case never create a new super if the old one is gone.
*/
static int fuse_set_no_super(struct super_block *sb, struct fs_context *fsc)
{
return -ENOTCONN;
}
static int fuse_test_super(struct super_block *sb, struct fs_context *fsc)
{
return fsc->sget_key == get_fuse_conn_super(sb);
}
static int fuse_get_tree(struct fs_context *fsc)
{
struct fuse_fs_context *ctx = fsc->fs_private;
struct fuse_dev *fud;
struct fuse_conn *fc;
struct fuse_mount *fm;
struct super_block *sb;
int err;
fc = kmalloc(sizeof(*fc), GFP_KERNEL);
if (!fc)
return -ENOMEM;
fm = kzalloc(sizeof(*fm), GFP_KERNEL);
if (!fm) {
kfree(fc);
return -ENOMEM;
}
fuse_conn_init(fc, fm, fsc->user_ns, &fuse_dev_fiq_ops, NULL);
fc->release = fuse_free_conn;
fsc->s_fs_info = fm;
if (ctx->fd_present)
ctx->file = fget(ctx->fd);
if (IS_ENABLED(CONFIG_BLOCK) && ctx->is_bdev) {
err = get_tree_bdev(fsc, fuse_fill_super);
goto out;
}
/*
* While block dev mount can be initialized with a dummy device fd
* (found by device name), normal fuse mounts can't
*/
err = -EINVAL;
if (!ctx->file)
goto out;
/*
* Allow creating a fuse mount with an already initialized fuse
* connection
*/
fud = READ_ONCE(ctx->file->private_data);
if (ctx->file->f_op == &fuse_dev_operations && fud) {
fsc->sget_key = fud->fc;
sb = sget_fc(fsc, fuse_test_super, fuse_set_no_super);
err = PTR_ERR_OR_ZERO(sb);
if (!IS_ERR(sb))
fsc->root = dget(sb->s_root);
} else {
err = get_tree_nodev(fsc, fuse_fill_super);
}
out:
if (fsc->s_fs_info)
fuse_mount_destroy(fm);
if (ctx->file)
fput(ctx->file);
return err;
}
static const struct fs_context_operations fuse_context_ops = {
.free = fuse_free_fsc,
.parse_param = fuse_parse_param,
.reconfigure = fuse_reconfigure,
.get_tree = fuse_get_tree,
};
/*
* Set up the filesystem mount context.
*/
static int fuse_init_fs_context(struct fs_context *fsc)
{
struct fuse_fs_context *ctx;
ctx = kzalloc(sizeof(struct fuse_fs_context), GFP_KERNEL);
if (!ctx)
return -ENOMEM;
ctx->max_read = ~0;
ctx->blksize = FUSE_DEFAULT_BLKSIZE;
ctx->legacy_opts_show = true;
#ifdef CONFIG_BLOCK
if (fsc->fs_type == &fuseblk_fs_type) {
ctx->is_bdev = true;
ctx->destroy = true;
}
#endif
fsc->fs_private = ctx;
fsc->ops = &fuse_context_ops;
return 0;
}
bool fuse_mount_remove(struct fuse_mount *fm)
{
struct fuse_conn *fc = fm->fc;
bool last = false;
down_write(&fc->killsb);
list_del_init(&fm->fc_entry);
if (list_empty(&fc->mounts))
last = true;
up_write(&fc->killsb);
return last;
}
EXPORT_SYMBOL_GPL(fuse_mount_remove);
void fuse_conn_destroy(struct fuse_mount *fm)
{
struct fuse_conn *fc = fm->fc;
if (fc->destroy)
fuse_send_destroy(fm);
fuse_abort_conn(fc);
fuse_wait_aborted(fc);
if (!list_empty(&fc->entry)) {
mutex_lock(&fuse_mutex);
list_del(&fc->entry);
fuse_ctl_remove_conn(fc);
mutex_unlock(&fuse_mutex);
}
}
EXPORT_SYMBOL_GPL(fuse_conn_destroy);
static void fuse_sb_destroy(struct super_block *sb)
{
struct fuse_mount *fm = get_fuse_mount_super(sb);
bool last;
if (sb->s_root) {
last = fuse_mount_remove(fm);
if (last)
fuse_conn_destroy(fm);
}
}
void fuse_mount_destroy(struct fuse_mount *fm)
{
fuse_conn_put(fm->fc);
kfree(fm);
}
EXPORT_SYMBOL(fuse_mount_destroy);
static void fuse_kill_sb_anon(struct super_block *sb)
{
fuse_sb_destroy(sb);
kill_anon_super(sb);
fuse_mount_destroy(get_fuse_mount_super(sb));
}
static struct file_system_type fuse_fs_type = {
.owner = THIS_MODULE,
.name = "fuse",
.fs_flags = FS_HAS_SUBTYPE | FS_USERNS_MOUNT,
.init_fs_context = fuse_init_fs_context,
.parameters = fuse_fs_parameters,
.kill_sb = fuse_kill_sb_anon,
};
MODULE_ALIAS_FS("fuse");
#ifdef CONFIG_BLOCK
static void fuse_kill_sb_blk(struct super_block *sb)
{
fuse_sb_destroy(sb);
kill_block_super(sb);
fuse_mount_destroy(get_fuse_mount_super(sb));
}
static struct file_system_type fuseblk_fs_type = {
.owner = THIS_MODULE,
.name = "fuseblk",
.init_fs_context = fuse_init_fs_context,
.parameters = fuse_fs_parameters,
.kill_sb = fuse_kill_sb_blk,
.fs_flags = FS_REQUIRES_DEV | FS_HAS_SUBTYPE,
};
MODULE_ALIAS_FS("fuseblk");
static inline int register_fuseblk(void)
{
return register_filesystem(&fuseblk_fs_type);
}
static inline void unregister_fuseblk(void)
{
unregister_filesystem(&fuseblk_fs_type);
}
#else
static inline int register_fuseblk(void)
{
return 0;
}
static inline void unregister_fuseblk(void)
{
}
#endif
static void fuse_inode_init_once(void *foo)
{
struct inode *inode = foo;
inode_init_once(inode);
}
static int __init fuse_fs_init(void)
{
int err;
fuse_inode_cachep = kmem_cache_create("fuse_inode",
sizeof(struct fuse_inode), 0,
SLAB_HWCACHE_ALIGN|SLAB_ACCOUNT|SLAB_RECLAIM_ACCOUNT,
fuse_inode_init_once);
err = -ENOMEM;
if (!fuse_inode_cachep)
goto out;
err = register_fuseblk();
if (err)
goto out2;
err = register_filesystem(&fuse_fs_type);
if (err)
goto out3;
return 0;
out3:
unregister_fuseblk();
out2:
kmem_cache_destroy(fuse_inode_cachep);
out:
return err;
}
static void fuse_fs_cleanup(void)
{
unregister_filesystem(&fuse_fs_type);
unregister_fuseblk();
/*
* Make sure all delayed rcu free inodes are flushed before we
* destroy cache.
*/
rcu_barrier();
kmem_cache_destroy(fuse_inode_cachep);
}
static struct kobject *fuse_kobj;
static ssize_t fuse_bpf_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buff)
{
return sysfs_emit(buff, "supported\n");
}
static struct kobj_attribute fuse_bpf_attr =
__ATTR_RO(fuse_bpf);
static struct attribute *bpf_features[] = {
&fuse_bpf_attr.attr,
NULL,
};
static const struct attribute_group bpf_features_group = {
.name = "features",
.attrs = bpf_features,
};
/*
* TODO Remove this once fuse-bpf is upstreamed
*
* bpf_prog_type_fuse exports the bpf_prog_type_fuse 'constant', which cannot be
* constant until the code is upstreamed
*/
static ssize_t bpf_prog_type_fuse_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buff)
{
return sysfs_emit(buff, "%d\n", BPF_PROG_TYPE_FUSE);
}
static struct kobj_attribute bpf_prog_type_fuse_attr =
__ATTR_RO(bpf_prog_type_fuse);
static struct attribute *bpf_attributes[] = {
&bpf_prog_type_fuse_attr.attr,
NULL,
};
static const struct attribute_group bpf_attr_group = {
.attrs = bpf_attributes,
};
static const struct attribute_group *attribute_groups[] = {
&bpf_features_group,
&bpf_attr_group,
NULL
};
/* TODO remove to here */
static int fuse_sysfs_init(void)
{
int err;
fuse_kobj = kobject_create_and_add("fuse", fs_kobj);
if (!fuse_kobj) {
err = -ENOMEM;
goto out_err;
}
err = sysfs_create_mount_point(fuse_kobj, "connections");
if (err)
goto out_fuse_unregister;
/* TODO Remove when BPF_PROG_TYPE_FUSE is upstreamed */
err = sysfs_create_groups(fuse_kobj, attribute_groups);
if (err)
goto out_fuse_remove_mount_point;
return 0;
out_fuse_remove_mount_point:
sysfs_remove_mount_point(fuse_kobj, "connections");
out_fuse_unregister:
kobject_put(fuse_kobj);
out_err:
return err;
}
static void fuse_sysfs_cleanup(void)
{
sysfs_remove_groups(fuse_kobj, attribute_groups);
sysfs_remove_mount_point(fuse_kobj, "connections");
kobject_put(fuse_kobj);
}
static int __init fuse_init(void)
{
int res;
pr_info("init (API version %i.%i)\n",
FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION);
INIT_LIST_HEAD(&fuse_conn_list);
res = fuse_fs_init();
if (res)
goto err;
res = fuse_dev_init();
if (res)
goto err_fs_cleanup;
res = fuse_sysfs_init();
if (res)
goto err_dev_cleanup;
res = fuse_ctl_init();
if (res)
goto err_sysfs_cleanup;
#ifdef CONFIG_FUSE_BPF
res = fuse_bpf_init();
if (res)
goto err_ctl_cleanup;
#endif
sanitize_global_limit(&max_user_bgreq);
sanitize_global_limit(&max_user_congthresh);
return 0;
#ifdef CONFIG_FUSE_BPF
err_ctl_cleanup:
fuse_ctl_cleanup();
#endif
err_sysfs_cleanup:
fuse_sysfs_cleanup();
err_dev_cleanup:
fuse_dev_cleanup();
err_fs_cleanup:
fuse_fs_cleanup();
err:
return res;
}
static void __exit fuse_exit(void)
{
pr_debug("exit\n");
fuse_ctl_cleanup();
fuse_sysfs_cleanup();
fuse_fs_cleanup();
#ifdef CONFIG_FUSE_BPF
fuse_bpf_cleanup();
#endif
fuse_dev_cleanup();
}
module_init(fuse_init);
module_exit(fuse_exit);