kernel-ark/fs/fuse/inode.c
Miklos Szeredi 7c352bdf04 [PATCH] FUSE: don't allow restarting of system calls
This patch removes ability to interrupt and restart operations while there
hasn't been any side-effect.

The reason: applications.  There are some apps it seems that generate
signals at a fast rate.  This means, that if the operation cannot make
enough progress between two signals, it will be restarted for ever.  This
bug actually manifested itself with 'krusader' trying to open a file for
writing under sshfs.  Thanks to Eduard Czimbalmos for the report.

The problem can be solved just by making open() uninterruptible, because in
this case it was the truncate operation that slowed down the progress.  But
it's better to solve this by simply not allowing interrupts at all (except
SIGKILL), because applications don't expect file operations to be
interruptible anyway.  As an added bonus the code is simplified somewhat.

Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-09 14:03:48 -07:00

592 lines
13 KiB
C

/*
FUSE: Filesystem in Userspace
Copyright (C) 2001-2005 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/mount.h>
#include <linux/seq_file.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/parser.h>
#include <linux/statfs.h>
MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>");
MODULE_DESCRIPTION("Filesystem in Userspace");
MODULE_LICENSE("GPL");
spinlock_t fuse_lock;
static kmem_cache_t *fuse_inode_cachep;
#define FUSE_SUPER_MAGIC 0x65735546
struct fuse_mount_data {
int fd;
unsigned rootmode;
unsigned user_id;
unsigned 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;
};
static struct inode *fuse_alloc_inode(struct super_block *sb)
{
struct inode *inode;
struct fuse_inode *fi;
inode = kmem_cache_alloc(fuse_inode_cachep, SLAB_KERNEL);
if (!inode)
return NULL;
fi = get_fuse_inode(inode);
fi->i_time = jiffies - 1;
fi->nodeid = 0;
fi->nlookup = 0;
fi->forget_req = fuse_request_alloc();
if (!fi->forget_req) {
kmem_cache_free(fuse_inode_cachep, inode);
return NULL;
}
return inode;
}
static void fuse_destroy_inode(struct inode *inode)
{
struct fuse_inode *fi = get_fuse_inode(inode);
if (fi->forget_req)
fuse_request_free(fi->forget_req);
kmem_cache_free(fuse_inode_cachep, inode);
}
static void fuse_read_inode(struct inode *inode)
{
/* No op */
}
void fuse_send_forget(struct fuse_conn *fc, struct fuse_req *req,
unsigned long nodeid, u64 nlookup)
{
struct fuse_forget_in *inarg = &req->misc.forget_in;
inarg->nlookup = nlookup;
req->in.h.opcode = FUSE_FORGET;
req->in.h.nodeid = nodeid;
req->in.numargs = 1;
req->in.args[0].size = sizeof(struct fuse_forget_in);
req->in.args[0].value = inarg;
request_send_noreply(fc, req);
}
static void fuse_clear_inode(struct 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_send_forget(fc, fi->forget_req, fi->nodeid, fi->nlookup);
fi->forget_req = NULL;
}
}
void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr)
{
if (S_ISREG(inode->i_mode) && i_size_read(inode) != attr->size)
invalidate_inode_pages(inode->i_mapping);
inode->i_ino = attr->ino;
inode->i_mode = (inode->i_mode & S_IFMT) + (attr->mode & 07777);
inode->i_nlink = attr->nlink;
inode->i_uid = attr->uid;
inode->i_gid = attr->gid;
i_size_write(inode, attr->size);
inode->i_blksize = PAGE_CACHE_SIZE;
inode->i_blocks = attr->blocks;
inode->i_atime.tv_sec = attr->atime;
inode->i_atime.tv_nsec = attr->atimensec;
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;
}
static void fuse_init_inode(struct inode *inode, struct fuse_attr *attr)
{
inode->i_mode = attr->mode & S_IFMT;
i_size_write(inode, attr->size);
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 {
/* Don't let user create weird files */
inode->i_mode = S_IFREG;
fuse_init_common(inode);
fuse_init_file_inode(inode);
}
}
static int fuse_inode_eq(struct inode *inode, void *_nodeidp)
{
unsigned long nodeid = *(unsigned long *) _nodeidp;
if (get_node_id(inode) == nodeid)
return 1;
else
return 0;
}
static int fuse_inode_set(struct inode *inode, void *_nodeidp)
{
unsigned long nodeid = *(unsigned long *) _nodeidp;
get_fuse_inode(inode)->nodeid = nodeid;
return 0;
}
struct inode *fuse_iget(struct super_block *sb, unsigned long nodeid,
int generation, struct fuse_attr *attr)
{
struct inode *inode;
struct fuse_inode *fi;
struct fuse_conn *fc = get_fuse_conn_super(sb);
int retried = 0;
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|S_NOCMTIME;
inode->i_generation = generation;
inode->i_data.backing_dev_info = &fc->bdi;
fuse_init_inode(inode, attr);
unlock_new_inode(inode);
} else if ((inode->i_mode ^ attr->mode) & S_IFMT) {
BUG_ON(retried);
/* Inode has changed type, any I/O on the old should fail */
make_bad_inode(inode);
iput(inode);
retried = 1;
goto retry;
}
fi = get_fuse_inode(inode);
fi->nlookup ++;
fuse_change_attributes(inode, attr);
return inode;
}
static void fuse_put_super(struct super_block *sb)
{
struct fuse_conn *fc = get_fuse_conn_super(sb);
down_write(&fc->sbput_sem);
while (!list_empty(&fc->background))
fuse_release_background(list_entry(fc->background.next,
struct fuse_req, bg_entry));
spin_lock(&fuse_lock);
fc->mounted = 0;
fc->user_id = 0;
fc->group_id = 0;
fc->flags = 0;
/* Flush all readers on this fs */
wake_up_all(&fc->waitq);
up_write(&fc->sbput_sem);
fuse_release_conn(fc);
spin_unlock(&fuse_lock);
}
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_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 super_block *sb, struct kstatfs *buf)
{
struct fuse_conn *fc = get_fuse_conn_super(sb);
struct fuse_req *req;
struct fuse_statfs_out outarg;
int err;
req = fuse_get_request(fc);
if (!req)
return -EINTR;
req->in.numargs = 0;
req->in.h.opcode = FUSE_STATFS;
req->out.numargs = 1;
req->out.args[0].size = sizeof(outarg);
req->out.args[0].value = &outarg;
request_send(fc, req);
err = req->out.h.error;
if (!err)
convert_fuse_statfs(buf, &outarg.st);
fuse_put_request(fc, req);
return err;
}
enum {
OPT_FD,
OPT_ROOTMODE,
OPT_USER_ID,
OPT_GROUP_ID,
OPT_DEFAULT_PERMISSIONS,
OPT_ALLOW_OTHER,
OPT_MAX_READ,
OPT_ERR
};
static 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_ERR, NULL}
};
static int parse_fuse_opt(char *opt, struct fuse_mount_data *d)
{
char *p;
memset(d, 0, sizeof(struct fuse_mount_data));
d->max_read = ~0;
while ((p = strsep(&opt, ",")) != NULL) {
int token;
int value;
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;
d->rootmode = value;
d->rootmode_present = 1;
break;
case OPT_USER_ID:
if (match_int(&args[0], &value))
return 0;
d->user_id = value;
d->user_id_present = 1;
break;
case OPT_GROUP_ID:
if (match_int(&args[0], &value))
return 0;
d->group_id = value;
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;
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 vfsmount *mnt)
{
struct fuse_conn *fc = get_fuse_conn_super(mnt->mnt_sb);
seq_printf(m, ",user_id=%u", fc->user_id);
seq_printf(m, ",group_id=%u", 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);
return 0;
}
static void free_conn(struct fuse_conn *fc)
{
while (!list_empty(&fc->unused_list)) {
struct fuse_req *req;
req = list_entry(fc->unused_list.next, struct fuse_req, list);
list_del(&req->list);
fuse_request_free(req);
}
kfree(fc);
}
/* Must be called with the fuse lock held */
void fuse_release_conn(struct fuse_conn *fc)
{
fc->count--;
if (!fc->count)
free_conn(fc);
}
static struct fuse_conn *new_conn(void)
{
struct fuse_conn *fc;
fc = kmalloc(sizeof(*fc), GFP_KERNEL);
if (fc != NULL) {
int i;
memset(fc, 0, sizeof(*fc));
init_waitqueue_head(&fc->waitq);
INIT_LIST_HEAD(&fc->pending);
INIT_LIST_HEAD(&fc->processing);
INIT_LIST_HEAD(&fc->unused_list);
INIT_LIST_HEAD(&fc->background);
sema_init(&fc->outstanding_sem, 0);
init_rwsem(&fc->sbput_sem);
for (i = 0; i < FUSE_MAX_OUTSTANDING; i++) {
struct fuse_req *req = fuse_request_alloc();
if (!req) {
free_conn(fc);
return NULL;
}
list_add(&req->list, &fc->unused_list);
}
fc->bdi.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE;
fc->bdi.unplug_io_fn = default_unplug_io_fn;
fc->reqctr = 0;
}
return fc;
}
static struct fuse_conn *get_conn(struct file *file, struct super_block *sb)
{
struct fuse_conn *fc;
if (file->f_op != &fuse_dev_operations)
return ERR_PTR(-EINVAL);
fc = new_conn();
if (fc == NULL)
return ERR_PTR(-ENOMEM);
spin_lock(&fuse_lock);
if (file->private_data) {
free_conn(fc);
fc = ERR_PTR(-EINVAL);
} else {
file->private_data = fc;
*get_fuse_conn_super_p(sb) = fc;
fc->mounted = 1;
fc->connected = 1;
fc->count = 2;
}
spin_unlock(&fuse_lock);
return fc;
}
static struct inode *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;
return fuse_iget(sb, 1, 0, &attr);
}
static struct super_operations fuse_super_operations = {
.alloc_inode = fuse_alloc_inode,
.destroy_inode = fuse_destroy_inode,
.read_inode = fuse_read_inode,
.clear_inode = fuse_clear_inode,
.put_super = fuse_put_super,
.statfs = fuse_statfs,
.show_options = fuse_show_options,
};
static int fuse_fill_super(struct super_block *sb, void *data, int silent)
{
struct fuse_conn *fc;
struct inode *root;
struct fuse_mount_data d;
struct file *file;
int err;
if (!parse_fuse_opt((char *) data, &d))
return -EINVAL;
sb->s_blocksize = PAGE_CACHE_SIZE;
sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
sb->s_magic = FUSE_SUPER_MAGIC;
sb->s_op = &fuse_super_operations;
sb->s_maxbytes = MAX_LFS_FILESIZE;
file = fget(d.fd);
if (!file)
return -EINVAL;
fc = get_conn(file, sb);
fput(file);
if (IS_ERR(fc))
return PTR_ERR(fc);
fc->flags = d.flags;
fc->user_id = d.user_id;
fc->group_id = d.group_id;
fc->max_read = d.max_read;
if (fc->max_read / PAGE_CACHE_SIZE < fc->bdi.ra_pages)
fc->bdi.ra_pages = fc->max_read / PAGE_CACHE_SIZE;
fc->max_write = FUSE_MAX_IN / 2;
err = -ENOMEM;
root = get_root_inode(sb, d.rootmode);
if (root == NULL)
goto err;
sb->s_root = d_alloc_root(root);
if (!sb->s_root) {
iput(root);
goto err;
}
fuse_send_init(fc);
return 0;
err:
spin_lock(&fuse_lock);
fuse_release_conn(fc);
spin_unlock(&fuse_lock);
return err;
}
static struct super_block *fuse_get_sb(struct file_system_type *fs_type,
int flags, const char *dev_name,
void *raw_data)
{
return get_sb_nodev(fs_type, flags, raw_data, fuse_fill_super);
}
static struct file_system_type fuse_fs_type = {
.owner = THIS_MODULE,
.name = "fuse",
.get_sb = fuse_get_sb,
.kill_sb = kill_anon_super,
};
static void fuse_inode_init_once(void *foo, kmem_cache_t *cachep,
unsigned long flags)
{
struct inode * inode = foo;
if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
SLAB_CTOR_CONSTRUCTOR)
inode_init_once(inode);
}
static int __init fuse_fs_init(void)
{
int err;
err = register_filesystem(&fuse_fs_type);
if (err)
printk("fuse: failed to register filesystem\n");
else {
fuse_inode_cachep = kmem_cache_create("fuse_inode",
sizeof(struct fuse_inode),
0, SLAB_HWCACHE_ALIGN,
fuse_inode_init_once, NULL);
if (!fuse_inode_cachep) {
unregister_filesystem(&fuse_fs_type);
err = -ENOMEM;
}
}
return err;
}
static void fuse_fs_cleanup(void)
{
unregister_filesystem(&fuse_fs_type);
kmem_cache_destroy(fuse_inode_cachep);
}
static int __init fuse_init(void)
{
int res;
printk("fuse init (API version %i.%i)\n",
FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION);
spin_lock_init(&fuse_lock);
res = fuse_fs_init();
if (res)
goto err;
res = fuse_dev_init();
if (res)
goto err_fs_cleanup;
return 0;
err_fs_cleanup:
fuse_fs_cleanup();
err:
return res;
}
static void __exit fuse_exit(void)
{
printk(KERN_DEBUG "fuse exit\n");
fuse_fs_cleanup();
fuse_dev_cleanup();
}
module_init(fuse_init);
module_exit(fuse_exit);