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inode.c
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/*
FUSE: Filesystem in Userspace
Copyright (C) 2001-2008 Miklos Szeredi <[email protected]>
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>
#include <uapi/linux/magic.h>
MODULE_AUTHOR("Miklos Szeredi <[email protected]>");
MODULE_DESCRIPTION("Filesystem in Userspace");
MODULE_LICENSE("GPL");
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 int fuse_max_pages_limit = 256;
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 fuse_submount_lookup *fuse_alloc_submount_lookup(void)
{
struct fuse_submount_lookup *sl;
sl = kzalloc(sizeof(struct fuse_submount_lookup), GFP_KERNEL_ACCOUNT);
if (!sl)
return NULL;
sl->forget = fuse_alloc_forget();
if (!sl->forget)
goto out_free;
return sl;
out_free:
kfree(sl);
return NULL;
}
static struct inode *fuse_alloc_inode(struct super_block *sb)
{
struct fuse_inode *fi;
fi = alloc_inode_sb(sb, fuse_inode_cachep, GFP_KERNEL);
if (!fi)
return NULL;
fi->i_time = 0;
fi->inval_mask = ~0;
fi->nodeid = 0;
fi->nlookup = 0;
fi->attr_version = 0;
fi->orig_ino = 0;
fi->state = 0;
fi->submount_lookup = NULL;
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;
if (IS_ENABLED(CONFIG_FUSE_PASSTHROUGH))
fuse_inode_backing_set(fi, NULL);
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
if (IS_ENABLED(CONFIG_FUSE_PASSTHROUGH))
fuse_backing_put(fuse_inode_backing(fi));
kmem_cache_free(fuse_inode_cachep, fi);
}
static void fuse_cleanup_submount_lookup(struct fuse_conn *fc,
struct fuse_submount_lookup *sl)
{
if (!refcount_dec_and_test(&sl->count))
return;
fuse_queue_forget(fc, sl->forget, sl->nodeid, 1);
sl->forget = NULL;
kfree(sl);
}
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);
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 (fi->submount_lookup) {
fuse_cleanup_submount_lookup(fc, fi->submount_lookup);
fi->submount_lookup = NULL;
}
/*
* Evict of non-deleted inode may race with outstanding
* LOOKUP/READDIRPLUS requests and result in inconsistency when
* the request finishes. Deal with that here by bumping a
* counter that can be compared to the starting value.
*/
if (inode->i_nlink > 0)
atomic64_inc(&fc->evict_ctr);
}
if (S_ISREG(inode->i_mode) && !fuse_is_bad(inode)) {
WARN_ON(fi->iocachectr != 0);
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;
}
void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr,
struct fuse_statx *sx,
u64 attr_valid, u32 cache_mask,
u64 evict_ctr)
{
struct fuse_conn *fc = get_fuse_conn(inode);
struct fuse_inode *fi = get_fuse_inode(inode);
lockdep_assert_held(&fi->lock);
/*
* Clear basic stats from invalid mask.
*
* Don't do this if this is coming from a fuse_iget() call and there
* might have been a racing evict which would've invalidated the result
* if the attr_version would've been preserved.
*
* !evict_ctr -> this is create
* fi->attr_version != 0 -> this is not a new inode
* evict_ctr == fuse_get_evict_ctr() -> no evicts while during request
*/
if (!evict_ctr || fi->attr_version || evict_ctr == fuse_get_evict_ctr(fc))
set_mask_bits(&fi->inval_mask, STATX_BASIC_STATS, 0);
fi->attr_version = atomic64_inc_return(&fc->attr_version);
fi->i_time = attr_valid;
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_set_atime(inode, attr->atime, attr->atimensec);
/* mtime from server may be stale due to local buffered write */
if (!(cache_mask & STATX_MTIME)) {
inode_set_mtime(inode, attr->mtime, attr->mtimensec);
}
if (!(cache_mask & STATX_CTIME)) {
inode_set_ctime(inode, attr->ctime, attr->ctimensec);
}
if (sx) {
/* Sanitize nsecs */
sx->btime.tv_nsec =
min_t(u32, sx->btime.tv_nsec, NSEC_PER_SEC - 1);
/*
* Btime has been queried, cache is valid (whether or not btime
* is available or not) so clear STATX_BTIME from inval_mask.
*
* Availability of the btime attribute is indicated in
* FUSE_I_BTIME
*/
set_mask_bits(&fi->inval_mask, STATX_BTIME, 0);
if (sx->mask & STATX_BTIME) {
set_bit(FUSE_I_BTIME, &fi->state);
fi->i_btime.tv_sec = sx->btime.tv_sec;
fi->i_btime.tv_nsec = sx->btime.tv_nsec;
}
}
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;
}
u32 fuse_get_cache_mask(struct inode *inode)
{
struct fuse_conn *fc = get_fuse_conn(inode);
if (!fc->writeback_cache || !S_ISREG(inode->i_mode))
return 0;
return STATX_MTIME | STATX_CTIME | STATX_SIZE;
}
static void fuse_change_attributes_i(struct inode *inode, struct fuse_attr *attr,
struct fuse_statx *sx, u64 attr_valid,
u64 attr_version, u64 evict_ctr)
{
struct fuse_conn *fc = get_fuse_conn(inode);
struct fuse_inode *fi = get_fuse_inode(inode);
u32 cache_mask;
loff_t oldsize;
struct timespec64 old_mtime;
spin_lock(&fi->lock);
/*
* In case of writeback_cache enabled, writes update mtime, ctime and
* may update i_size. In these cases trust the cached value in the
* inode.
*/
cache_mask = fuse_get_cache_mask(inode);
if (cache_mask & STATX_SIZE)
attr->size = i_size_read(inode);
if (cache_mask & STATX_MTIME) {
attr->mtime = inode_get_mtime_sec(inode);
attr->mtimensec = inode_get_mtime_nsec(inode);
}
if (cache_mask & STATX_CTIME) {
attr->ctime = inode_get_ctime_sec(inode);
attr->ctimensec = inode_get_ctime_nsec(inode);
}
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_get_mtime(inode);
fuse_change_attributes_common(inode, attr, sx, attr_valid, cache_mask,
evict_ctr);
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 (!(cache_mask & STATX_SIZE))
i_size_write(inode, attr->size);
spin_unlock(&fi->lock);
if (!cache_mask && 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);
}
if (IS_ENABLED(CONFIG_FUSE_DAX))
fuse_dax_dontcache(inode, attr->flags);
}
void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,
struct fuse_statx *sx, u64 attr_valid,
u64 attr_version)
{
fuse_change_attributes_i(inode, attr, sx, attr_valid, attr_version, 0);
}
static void fuse_init_submount_lookup(struct fuse_submount_lookup *sl,
u64 nodeid)
{
sl->nodeid = nodeid;
refcount_set(&sl->count, 1);
}
static void fuse_init_inode(struct inode *inode, struct fuse_attr *attr,
struct fuse_conn *fc)
{
inode->i_mode = attr->mode & S_IFMT;
inode->i_size = attr->size;
inode_set_mtime(inode, attr->mtime, attr->mtimensec);
inode_set_ctime(inode, attr->ctime, attr->ctimensec);
if (S_ISREG(inode->i_mode)) {
fuse_init_common(inode);
fuse_init_file_inode(inode, attr->flags);
} 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,
new_decode_dev(attr->rdev));
} else
BUG();
/*
* Ensure that we don't cache acls for daemons without FUSE_POSIX_ACL
* so they see the exact same behavior as before.
*/
if (!fc->posix_acl)
inode->i_acl = inode->i_default_acl = ACL_DONT_CACHE;
}
static int fuse_inode_eq(struct inode *inode, void *_nodeidp)
{
u64 nodeid = *(u64 *) _nodeidp;
if (get_node_id(inode) == nodeid)
return 1;
else
return 0;
}
static int fuse_inode_set(struct inode *inode, void *_nodeidp)
{
u64 nodeid = *(u64 *) _nodeidp;
get_fuse_inode(inode)->nodeid = nodeid;
return 0;
}
struct inode *fuse_iget(struct super_block *sb, u64 nodeid,
int generation, struct fuse_attr *attr,
u64 attr_valid, u64 attr_version,
u64 evict_ctr)
{
struct inode *inode;
struct fuse_inode *fi;
struct fuse_conn *fc = get_fuse_conn_super(sb);
/*
* 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)) {
struct fuse_inode *fi;
inode = new_inode(sb);
if (!inode)
return NULL;
fuse_init_inode(inode, attr, fc);
fi = get_fuse_inode(inode);
fi->nodeid = nodeid;
fi->submount_lookup = fuse_alloc_submount_lookup();
if (!fi->submount_lookup) {
iput(inode);
return NULL;
}
/* Sets nlookup = 1 on fi->submount_lookup->nlookup */
fuse_init_submount_lookup(fi->submount_lookup, nodeid);
inode->i_flags |= S_AUTOMOUNT;
goto done;
}
retry:
inode = iget5_locked(sb, nodeid, fuse_inode_eq, fuse_inode_set, &nodeid);
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, fc);
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);
if (inode != d_inode(sb->s_root)) {
remove_inode_hash(inode);
iput(inode);
goto retry;
}
}
fi = get_fuse_inode(inode);
spin_lock(&fi->lock);
fi->nlookup++;
spin_unlock(&fi->lock);
done:
fuse_change_attributes_i(inode, attr, NULL, attr_valid, attr_version,
evict_ctr);
return inode;
}
struct inode *fuse_ilookup(struct fuse_conn *fc, u64 nodeid,
struct fuse_mount **fm)
{
struct fuse_mount *fm_iter;
struct inode *inode;
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, &nodeid);
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)
return;
fuse_abort_conn(fc);
// Only retire block-device-based superblocks.
if (sb->s_bdev != NULL)
retire_super(sb);
}
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 void convert_fuse_statfs(struct kstatfs *stbuf, struct fuse_kstatfs *attr)
{
stbuf->f_type = FUSE_SUPER_MAGIC;
stbuf->f_bsize = attr->bsize;
stbuf->f_frsize = attr->frsize;
stbuf->f_blocks = attr->blocks;
stbuf->f_bfree = attr->bfree;
stbuf->f_bavail = attr->bavail;
stbuf->f_files = attr->files;
stbuf->f_ffree = attr->ffree;
stbuf->f_namelen = attr->namelen;
/* fsid is left zero */
}
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;
if (!fuse_allow_current_process(fm->fc)) {
buf->f_type = FUSE_SUPER_MAGIC;
return 0;
}
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_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_uid ("user_id", OPT_USER_ID),
fsparam_gid ("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),
{}
};
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;
kuid_t kuid;
kgid_t kgid;
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:
kuid = result.uid;
/*
* The requested uid must be representable in the
* filesystem's idmapping.
*/
if (!kuid_has_mapping(fsc->user_ns, kuid))
return invalfc(fsc, "Invalid user_id");
ctx->user_id = kuid;
ctx->user_id_present = true;
break;
case OPT_GROUP_ID:
kgid = result.gid;
/*
* The requested gid must be representable in the
* filesystem's idmapping.
*/
if (!kgid_has_mapping(fsc->user_ns, kgid))
return invalfc(fsc, "Invalid group_id");
ctx->group_id = kgid;
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;
default:
return -EINVAL;
}
return 0;
}
static void fuse_free_fsc(struct fs_context *fsc)
{
struct fuse_fs_context *ctx = fsc->fs_private;
if (ctx) {
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_mode == FUSE_DAX_ALWAYS)
seq_puts(m, ",dax=always");
else if (fc->dax_mode == FUSE_DAX_NEVER)
seq_puts(m, ",dax=never");
else if (fc->dax_mode == FUSE_DAX_INODE_USER)
seq_puts(m, ",dax=inode");
#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);
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);
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);
atomic64_set(&fc->evict_ctr, 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_pages_limit;
if (IS_ENABLED(CONFIG_FUSE_PASSTHROUGH))
fuse_backing_files_init(fc);
INIT_LIST_HEAD(&fc->mounts);
list_add(&fm->fc_entry, &fc->mounts);
fm->fc = fc;
}
EXPORT_SYMBOL_GPL(fuse_conn_init);
static void delayed_release(struct rcu_head *p)
{
struct fuse_conn *fc = container_of(p, struct fuse_conn, rcu);
put_user_ns(fc->user_ns);
fc->release(fc);
}
void fuse_conn_put(struct fuse_conn *fc)
{