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inode.c
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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/parser.h>
#include <linux/statfs.h>
#include <linux/random.h>
#include <linux/sched.h>
#include <linux/exportfs.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, 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_SUPER_MAGIC 0x65735546
#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)
struct fuse_mount_data {
int fd;
unsigned rootmode;
kuid_t user_id;
kgid_t group_id;
unsigned fd_present:1;
unsigned rootmode_present:1;
unsigned user_id_present:1;
unsigned group_id_present:1;
unsigned flags;
unsigned max_read;
unsigned blksize;
};
struct fuse_forget_link *fuse_alloc_forget(void)
{
return kzalloc(sizeof(struct fuse_forget_link), GFP_KERNEL);
}
static struct inode *fuse_alloc_inode(struct super_block *sb)
{
struct inode *inode;
struct fuse_inode *fi;
inode = kmem_cache_alloc(fuse_inode_cachep, GFP_KERNEL);
if (!inode)
return NULL;
fi = get_fuse_inode(inode);
fi->i_time = 0;
fi->nodeid = 0;
fi->nlookup = 0;
fi->attr_version = 0;
fi->writectr = 0;
fi->orig_ino = 0;
fi->state = 0;
INIT_LIST_HEAD(&fi->write_files);
INIT_LIST_HEAD(&fi->queued_writes);
INIT_LIST_HEAD(&fi->writepages);
init_waitqueue_head(&fi->page_waitq);
fi->forget = fuse_alloc_forget();
if (!fi->forget) {
kmem_cache_free(fuse_inode_cachep, inode);
return NULL;
}
return inode;
}
static void fuse_i_callback(struct rcu_head *head)
{
struct inode *inode = container_of(head, struct inode, i_rcu);
kmem_cache_free(fuse_inode_cachep, inode);
}
static void fuse_destroy_inode(struct inode *inode)
{
struct fuse_inode *fi = get_fuse_inode(inode);
BUG_ON(!list_empty(&fi->write_files));
BUG_ON(!list_empty(&fi->queued_writes));
kfree(fi->forget);
call_rcu(&inode->i_rcu, fuse_i_callback);
}
static void fuse_evict_inode(struct inode *inode)
{
truncate_inode_pages_final(&inode->i_data);
clear_inode(inode);
if (inode->i_sb->s_flags & MS_ACTIVE) {
struct fuse_conn *fc = get_fuse_conn(inode);
struct fuse_inode *fi = get_fuse_inode(inode);
fuse_queue_forget(fc, fi->forget, fi->nodeid, fi->nlookup);
fi->forget = NULL;
}
}
static int fuse_remount_fs(struct super_block *sb, int *flags, char *data)
{
sync_filesystem(sb);
if (*flags & MS_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,
u64 attr_valid)
{
struct fuse_conn *fc = get_fuse_conn(inode);
struct fuse_inode *fi = get_fuse_inode(inode);
fi->attr_version = ++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(&init_user_ns, attr->uid);
inode->i_gid = make_kgid(&init_user_ns, attr->gid);
inode->i_blocks = attr->blocks;
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->flags & FUSE_DEFAULT_PERMISSIONS))
inode->i_mode &= ~S_ISVTX;
fi->orig_ino = attr->ino;
}
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 timespec old_mtime;
spin_lock(&fc->lock);
if ((attr_version != 0 && fi->attr_version > attr_version) ||
test_bit(FUSE_I_SIZE_UNSTABLE, &fi->state)) {
spin_unlock(&fc->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(&fc->lock);
if (!is_wb && S_ISREG(inode->i_mode)) {
bool inval = false;
if (oldsize != attr->size) {
truncate_pagecache(inode, attr->size);
inval = true;
} else if (fc->auto_inval_data) {
struct timespec new_mtime = {
.tv_sec = attr->mtime,
.tv_nsec = attr->mtimensec,
};
/*
* Auto inval mode also checks and invalidates if mtime
* has changed.
*/
if (!timespec_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,
new_decode_dev(attr->rdev));
} else
BUG();
}
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)
{
struct inode *inode;
struct fuse_inode *fi;
struct fuse_conn *fc = get_fuse_conn_super(sb);
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);
unlock_new_inode(inode);
} else if ((inode->i_mode ^ attr->mode) & S_IFMT) {
/* Inode has changed type, any I/O on the old should fail */
make_bad_inode(inode);
iput(inode);
goto retry;
}
fi = get_fuse_inode(inode);
spin_lock(&fc->lock);
fi->nlookup++;
spin_unlock(&fc->lock);
fuse_change_attributes(inode, attr, attr_valid, attr_version);
return inode;
}
int fuse_reverse_inval_inode(struct super_block *sb, u64 nodeid,
loff_t offset, loff_t len)
{
struct inode *inode;
pgoff_t pg_start;
pgoff_t pg_end;
inode = ilookup5(sb, nodeid, fuse_inode_eq, &nodeid);
if (!inode)
return -ENOENT;
fuse_invalidate_attr(inode);
if (offset >= 0) {
pg_start = offset >> PAGE_CACHE_SHIFT;
if (len <= 0)
pg_end = -1;
else
pg_end = (offset + len - 1) >> PAGE_CACHE_SHIFT;
invalidate_inode_pages2_range(inode->i_mapping,
pg_start, pg_end);
}
iput(inode);
return 0;
}
static void fuse_umount_begin(struct super_block *sb)
{
fuse_abort_conn(get_fuse_conn_super(sb));
}
static void fuse_send_destroy(struct fuse_conn *fc)
{
struct fuse_req *req = fc->destroy_req;
if (req && fc->conn_init) {
fc->destroy_req = NULL;
req->in.h.opcode = FUSE_DESTROY;
__set_bit(FR_FORCE, &req->flags);
__clear_bit(FR_BACKGROUND, &req->flags);
fuse_request_send(fc, req);
fuse_put_request(fc, req);
}
}
static void fuse_bdi_destroy(struct fuse_conn *fc)
{
if (fc->bdi_initialized)
bdi_destroy(&fc->bdi);
}
static void fuse_put_super(struct super_block *sb)
{
struct fuse_conn *fc = get_fuse_conn_super(sb);
fuse_send_destroy(fc);
fuse_abort_conn(fc);
mutex_lock(&fuse_mutex);
list_del(&fc->entry);
fuse_ctl_remove_conn(fc);
mutex_unlock(&fuse_mutex);
fuse_bdi_destroy(fc);
fuse_conn_put(fc);
}
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_conn *fc = get_fuse_conn_super(sb);
FUSE_ARGS(args);
struct fuse_statfs_out outarg;
int err;
if (!fuse_allow_current_process(fc)) {
buf->f_type = FUSE_SUPER_MAGIC;
return 0;
}
memset(&outarg, 0, sizeof(outarg));
args.in.numargs = 0;
args.in.h.opcode = FUSE_STATFS;
args.in.h.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(fc, &args);
if (!err)
convert_fuse_statfs(buf, &outarg.st);
return err;
}
enum {
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 match_table_t tokens = {
{OPT_FD, "fd=%u"},
{OPT_ROOTMODE, "rootmode=%o"},
{OPT_USER_ID, "user_id=%u"},
{OPT_GROUP_ID, "group_id=%u"},
{OPT_DEFAULT_PERMISSIONS, "default_permissions"},
{OPT_ALLOW_OTHER, "allow_other"},
{OPT_MAX_READ, "max_read=%u"},
{OPT_BLKSIZE, "blksize=%u"},
{OPT_ERR, NULL}
};
static int fuse_match_uint(substring_t *s, unsigned int *res)
{
int err = -ENOMEM;
char *buf = match_strdup(s);
if (buf) {
err = kstrtouint(buf, 10, res);
kfree(buf);
}
return err;
}
static int parse_fuse_opt(char *opt, struct fuse_mount_data *d, int is_bdev)
{
char *p;
memset(d, 0, sizeof(struct fuse_mount_data));
d->max_read = ~0;
d->blksize = FUSE_DEFAULT_BLKSIZE;
while ((p = strsep(&opt, ",")) != NULL) {
int token;
int value;
unsigned uv;
substring_t args[MAX_OPT_ARGS];
if (!*p)
continue;
token = match_token(p, tokens, args);
switch (token) {
case OPT_FD:
if (match_int(&args[0], &value))
return 0;
d->fd = value;
d->fd_present = 1;
break;
case OPT_ROOTMODE:
if (match_octal(&args[0], &value))
return 0;
if (!fuse_valid_type(value))
return 0;
d->rootmode = value;
d->rootmode_present = 1;
break;
case OPT_USER_ID:
if (fuse_match_uint(&args[0], &uv))
return 0;
d->user_id = make_kuid(current_user_ns(), uv);
if (!uid_valid(d->user_id))
return 0;
d->user_id_present = 1;
break;
case OPT_GROUP_ID:
if (fuse_match_uint(&args[0], &uv))
return 0;
d->group_id = make_kgid(current_user_ns(), uv);
if (!gid_valid(d->group_id))
return 0;
d->group_id_present = 1;
break;
case OPT_DEFAULT_PERMISSIONS:
d->flags |= FUSE_DEFAULT_PERMISSIONS;
break;
case OPT_ALLOW_OTHER:
d->flags |= FUSE_ALLOW_OTHER;
break;
case OPT_MAX_READ:
if (match_int(&args[0], &value))
return 0;
d->max_read = value;
break;
case OPT_BLKSIZE:
if (!is_bdev || match_int(&args[0], &value))
return 0;
d->blksize = value;
break;
default:
return 0;
}
}
if (!d->fd_present || !d->rootmode_present ||
!d->user_id_present || !d->group_id_present)
return 0;
return 1;
}
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);
seq_printf(m, ",user_id=%u", from_kuid_munged(&init_user_ns, fc->user_id));
seq_printf(m, ",group_id=%u", from_kgid_munged(&init_user_ns, fc->group_id));
if (fc->flags & FUSE_DEFAULT_PERMISSIONS)
seq_puts(m, ",default_permissions");
if (fc->flags & FUSE_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);
return 0;
}
static void fuse_iqueue_init(struct fuse_iqueue *fiq)
{
memset(fiq, 0, sizeof(struct fuse_iqueue));
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;
}
static void fuse_pqueue_init(struct fuse_pqueue *fpq)
{
memset(fpq, 0, sizeof(struct fuse_pqueue));
spin_lock_init(&fpq->lock);
INIT_LIST_HEAD(&fpq->processing);
INIT_LIST_HEAD(&fpq->io);
fpq->connected = 1;
}
void fuse_conn_init(struct fuse_conn *fc)
{
memset(fc, 0, sizeof(*fc));
spin_lock_init(&fc->lock);
init_rwsem(&fc->killsb);
atomic_set(&fc->count, 1);
atomic_set(&fc->dev_count, 1);
init_waitqueue_head(&fc->blocked_waitq);
init_waitqueue_head(&fc->reserved_req_waitq);
fuse_iqueue_init(&fc->iq);
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;
fc->khctr = 0;
fc->polled_files = RB_ROOT;
fc->blocked = 0;
fc->initialized = 0;
fc->connected = 1;
fc->attr_version = 1;
get_random_bytes(&fc->scramble_key, sizeof(fc->scramble_key));
}
EXPORT_SYMBOL_GPL(fuse_conn_init);
void fuse_conn_put(struct fuse_conn *fc)
{
if (atomic_dec_and_test(&fc->count)) {
if (fc->destroy_req)
fuse_request_free(fc->destroy_req);
fc->release(fc);
}
}
EXPORT_SYMBOL_GPL(fuse_conn_put);
struct fuse_conn *fuse_conn_get(struct fuse_conn *fc)
{
atomic_inc(&fc->count);
return fc;
}
EXPORT_SYMBOL_GPL(fuse_conn_get);
static struct inode *fuse_get_root_inode(struct super_block *sb, unsigned mode)
{
struct fuse_attr attr;
memset(&attr, 0, sizeof(attr));
attr.mode = mode;
attr.ino = FUSE_ROOT_ID;
attr.nlink = 1;
return fuse_iget(sb, 1, 0, &attr, 0, 0);
}
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;
if (handle->nodeid == 0)
goto out_err;
inode = ilookup5(sb, handle->nodeid, fuse_inode_eq, &handle->nodeid);
if (!inode) {
struct fuse_entry_out outarg;
struct qstr name;
if (!fc->export_support)
goto out_err;
name.len = 1;
name.name = ".";
err = fuse_lookup_name(sb, handle->nodeid, &name, &outarg,
&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;
struct qstr name;
int err;
if (!fc->export_support)
return ERR_PTR(-ESTALE);
name.len = 2;
name.name = "..";
err = fuse_lookup_name(child_inode->i_sb, get_node_id(child_inode),
&name, &outarg, &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,
.destroy_inode = fuse_destroy_inode,
.evict_inode = fuse_evict_inode,
.write_inode = fuse_write_inode,
.drop_inode = generic_delete_inode,
.remount_fs = fuse_remount_fs,
.put_super = fuse_put_super,
.umount_begin = fuse_umount_begin,
.statfs = fuse_statfs,
.show_options = fuse_show_options,
};
static void sanitize_global_limit(unsigned *limit)
{
if (*limit == 0)
*limit = ((totalram_pages << PAGE_SHIFT) >> 13) /
sizeof(struct fuse_req);
if (*limit >= 1 << 16)
*limit = (1 << 16) - 1;
}
static int set_global_limit(const char *val, 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);
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;
}
}
static void process_init_reply(struct fuse_conn *fc, struct fuse_req *req)
{
struct fuse_init_out *arg = &req->misc.init_out;
if (req->out.h.error || arg->major != FUSE_KERNEL_VERSION)
fc->conn_error = 1;
else {
unsigned long ra_pages;
process_init_limits(fc, arg);
if (arg->minor >= 6) {
ra_pages = arg->max_readahead / PAGE_CACHE_SIZE;
if (arg->flags & FUSE_ASYNC_READ)
fc->async_read = 1;
if (!(arg->flags & FUSE_POSIX_LOCKS))
fc->no_lock = 1;
if (arg->minor >= 17) {
if (!(arg->flags & FUSE_FLOCK_LOCKS))
fc->no_flock = 1;
} else {
if (!(arg->flags & FUSE_POSIX_LOCKS))
fc->no_flock = 1;
}
if (arg->flags & FUSE_ATOMIC_O_TRUNC)
fc->atomic_o_trunc = 1;
if (arg->minor >= 9) {
/* LOOKUP has dependency on proto version */
if (arg->flags & FUSE_EXPORT_SUPPORT)
fc->export_support = 1;
}
if (arg->flags & FUSE_BIG_WRITES)
fc->big_writes = 1;
if (arg->flags & FUSE_DONT_MASK)
fc->dont_mask = 1;
if (arg->flags & FUSE_AUTO_INVAL_DATA)
fc->auto_inval_data = 1;
if (arg->flags & FUSE_DO_READDIRPLUS) {
fc->do_readdirplus = 1;
if (arg->flags & FUSE_READDIRPLUS_AUTO)
fc->readdirplus_auto = 1;
}
if (arg->flags & FUSE_ASYNC_DIO)
fc->async_dio = 1;
if (arg->flags & FUSE_WRITEBACK_CACHE)
fc->writeback_cache = 1;
if (arg->time_gran && arg->time_gran <= 1000000000)
fc->sb->s_time_gran = arg->time_gran;
} else {
ra_pages = fc->max_read / PAGE_CACHE_SIZE;
fc->no_lock = 1;
fc->no_flock = 1;
}
fc->bdi.ra_pages = min(fc->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;
}
fuse_set_initialized(fc);
wake_up_all(&fc->blocked_waitq);
}
static void fuse_send_init(struct fuse_conn *fc, struct fuse_req *req)
{
struct fuse_init_in *arg = &req->misc.init_in;
arg->major = FUSE_KERNEL_VERSION;
arg->minor = FUSE_KERNEL_MINOR_VERSION;
arg->max_readahead = fc->bdi.ra_pages * PAGE_CACHE_SIZE;
arg->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_IOCTL_DIR | FUSE_AUTO_INVAL_DATA |
FUSE_DO_READDIRPLUS | FUSE_READDIRPLUS_AUTO | FUSE_ASYNC_DIO |
FUSE_WRITEBACK_CACHE | FUSE_NO_OPEN_SUPPORT;
req->in.h.opcode = FUSE_INIT;
req->in.numargs = 1;
req->in.args[0].size = sizeof(*arg);
req->in.args[0].value = arg;
req->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 */
req->out.argvar = 1;
req->out.args[0].size = sizeof(struct fuse_init_out);
req->out.args[0].value = &req->misc.init_out;
req->end = process_init_reply;
fuse_request_send_background(fc, req);
}
static void fuse_free_conn(struct fuse_conn *fc)
{
WARN_ON(!list_empty(&fc->devices));
kfree_rcu(fc, rcu);
}
static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb)
{
int err;
fc->bdi.name = "fuse";
fc->bdi.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE;
/* fuse does it's own writeback accounting */
fc->bdi.capabilities = BDI_CAP_NO_ACCT_WB | BDI_CAP_STRICTLIMIT;
err = bdi_init(&fc->bdi);
if (err)
return err;
fc->bdi_initialized = 1;
if (sb->s_bdev) {
err = bdi_register(&fc->bdi, NULL, "%u:%u-fuseblk",
MAJOR(fc->dev), MINOR(fc->dev));
} else {
err = bdi_register_dev(&fc->bdi, fc->dev);
}
if (err)
return err;
/*
* 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(&fc->bdi, 1);
return 0;
}
struct fuse_dev *fuse_dev_alloc(struct fuse_conn *fc)
{
struct fuse_dev *fud;
fud = kzalloc(sizeof(struct fuse_dev), GFP_KERNEL);
if (fud) {