- 根目录:
- fs
- fuse
- file.c
/*
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/kernel.h>
#include <linux/sched.h>
#include <linux/module.h>
#include <linux/compat.h>
static const struct file_operations fuse_direct_io_file_operations;
static int fuse_send_open(struct fuse_conn *fc, u64 nodeid, struct file *file,
int opcode, struct fuse_open_out *outargp)
{
struct fuse_open_in inarg;
struct fuse_req *req;
int err;
req = fuse_get_req(fc);
if (IS_ERR(req))
return PTR_ERR(req);
memset(&inarg, 0, sizeof(inarg));
inarg.flags = file->f_flags & ~(O_CREAT | O_EXCL | O_NOCTTY);
if (!fc->atomic_o_trunc)
inarg.flags &= ~O_TRUNC;
req->in.h.opcode = opcode;
req->in.h.nodeid = nodeid;
req->in.numargs = 1;
req->in.args[0].size = sizeof(inarg);
req->in.args[0].value = &inarg;
req->out.numargs = 1;
req->out.args[0].size = sizeof(*outargp);
req->out.args[0].value = outargp;
fuse_request_send(fc, req);
err = req->out.h.error;
fuse_put_request(fc, req);
return err;
}
struct fuse_file *fuse_file_alloc(struct fuse_conn *fc)
{
struct fuse_file *ff;
ff = kmalloc(sizeof(struct fuse_file), GFP_KERNEL);
if (unlikely(!ff))
return NULL;
ff->fc = fc;
ff->reserved_req = fuse_request_alloc();
if (unlikely(!ff->reserved_req)) {
kfree(ff);
return NULL;
}
INIT_LIST_HEAD(&ff->write_entry);
atomic_set(&ff->count, 0);
RB_CLEAR_NODE(&ff->polled_node);
init_waitqueue_head(&ff->poll_wait);
spin_lock(&fc->lock);
ff->kh = ++fc->khctr;
spin_unlock(&fc->lock);
return ff;
}
void fuse_file_free(struct fuse_file *ff)
{
fuse_request_free(ff->reserved_req);
kfree(ff);
}
struct fuse_file *fuse_file_get(struct fuse_file *ff)
{
atomic_inc(&ff->count);
return ff;
}
static void fuse_release_async(struct work_struct *work)
{
struct fuse_req *req;
struct fuse_conn *fc;
struct path path;
req = container_of(work, struct fuse_req, misc.release.work);
path = req->misc.release.path;
fc = get_fuse_conn(path.dentry->d_inode);
fuse_put_request(fc, req);
path_put(&path);
}
static void fuse_release_end(struct fuse_conn *fc, struct fuse_req *req)
{
if (fc->destroy_req) {
/*
* If this is a fuseblk mount, then it's possible that
* releasing the path will result in releasing the
* super block and sending the DESTROY request. If
* the server is single threaded, this would hang.
* For this reason do the path_put() in a separate
* thread.
*/
atomic_inc(&req->count);
INIT_WORK(&req->misc.release.work, fuse_release_async);
schedule_work(&req->misc.release.work);
} else {
path_put(&req->misc.release.path);
}
}
static void fuse_file_put(struct fuse_file *ff, bool sync)
{
if (atomic_dec_and_test(&ff->count)) {
struct fuse_req *req = ff->reserved_req;
if (sync) {
fuse_request_send(ff->fc, req);
path_put(&req->misc.release.path);
fuse_put_request(ff->fc, req);
} else {
req->end = fuse_release_end;
fuse_request_send_background(ff->fc, req);
}
kfree(ff);
}
}
int fuse_do_open(struct fuse_conn *fc, u64 nodeid, struct file *file,
bool isdir)
{
struct fuse_open_out outarg;
struct fuse_file *ff;
int err;
int opcode = isdir ? FUSE_OPENDIR : FUSE_OPEN;
ff = fuse_file_alloc(fc);
if (!ff)
return -ENOMEM;
err = fuse_send_open(fc, nodeid, file, opcode, &outarg);
if (err) {
fuse_file_free(ff);
return err;
}
if (isdir)
outarg.open_flags &= ~FOPEN_DIRECT_IO;
ff->fh = outarg.fh;
ff->nodeid = nodeid;
ff->open_flags = outarg.open_flags;
file->private_data = fuse_file_get(ff);
return 0;
}
EXPORT_SYMBOL_GPL(fuse_do_open);
void fuse_finish_open(struct inode *inode, struct file *file)
{
struct fuse_file *ff = file->private_data;
struct fuse_conn *fc = get_fuse_conn(inode);
if (ff->open_flags & FOPEN_DIRECT_IO)
file->f_op = &fuse_direct_io_file_operations;
if (!(ff->open_flags & FOPEN_KEEP_CACHE))
invalidate_inode_pages2(inode->i_mapping);
if (ff->open_flags & FOPEN_NONSEEKABLE)
nonseekable_open(inode, file);
if (fc->atomic_o_trunc && (file->f_flags & O_TRUNC)) {
struct fuse_inode *fi = get_fuse_inode(inode);
spin_lock(&fc->lock);
fi->attr_version = ++fc->attr_version;
i_size_write(inode, 0);
spin_unlock(&fc->lock);
fuse_invalidate_attr(inode);
}
}
int fuse_open_common(struct inode *inode, struct file *file, bool isdir)
{
struct fuse_conn *fc = get_fuse_conn(inode);
int err;
/* VFS checks this, but only _after_ ->open() */
if (file->f_flags & O_DIRECT)
return -EINVAL;
err = generic_file_open(inode, file);
if (err)
return err;
err = fuse_do_open(fc, get_node_id(inode), file, isdir);
if (err)
return err;
fuse_finish_open(inode, file);
return 0;
}
static void fuse_prepare_release(struct fuse_file *ff, int flags, int opcode)
{
struct fuse_conn *fc = ff->fc;
struct fuse_req *req = ff->reserved_req;
struct fuse_release_in *inarg = &req->misc.release.in;
spin_lock(&fc->lock);
list_del(&ff->write_entry);
if (!RB_EMPTY_NODE(&ff->polled_node))
rb_erase(&ff->polled_node, &fc->polled_files);
spin_unlock(&fc->lock);
wake_up_interruptible_all(&ff->poll_wait);
inarg->fh = ff->fh;
inarg->flags = flags;
req->in.h.opcode = opcode;
req->in.h.nodeid = ff->nodeid;
req->in.numargs = 1;
req->in.args[0].size = sizeof(struct fuse_release_in);
req->in.args[0].value = inarg;
}
void fuse_release_common(struct file *file, int opcode)
{
struct fuse_file *ff;
struct fuse_req *req;
ff = file->private_data;
if (unlikely(!ff))
return;
req = ff->reserved_req;
fuse_prepare_release(ff, file->f_flags, opcode);
/* Hold vfsmount and dentry until release is finished */
path_get(&file->f_path);
req->misc.release.path = file->f_path;
/*
* Normally this will send the RELEASE request, however if
* some asynchronous READ or WRITE requests are outstanding,
* the sending will be delayed.
*
* Make the release synchronous if this is a fuseblk mount,
* synchronous RELEASE is allowed (and desirable) in this case
* because the server can be trusted not to screw up.
*/
fuse_file_put(ff, ff->fc->destroy_req != NULL);
}
static int fuse_open(struct inode *inode, struct file *file)
{
return fuse_open_common(inode, file, false);
}
static int fuse_release(struct inode *inode, struct file *file)
{
fuse_release_common(file, FUSE_RELEASE);
/* return value is ignored by VFS */
return 0;
}
void fuse_sync_release(struct fuse_file *ff, int flags)
{
WARN_ON(atomic_read(&ff->count) > 1);
fuse_prepare_release(ff, flags, FUSE_RELEASE);
ff->reserved_req->force = 1;
fuse_request_send(ff->fc, ff->reserved_req);
fuse_put_request(ff->fc, ff->reserved_req);
kfree(ff);
}
EXPORT_SYMBOL_GPL(fuse_sync_release);
/*
* Scramble the ID space with XTEA, so that the value of the files_struct
* pointer is not exposed to userspace.
*/
u64 fuse_lock_owner_id(struct fuse_conn *fc, fl_owner_t id)
{
u32 *k = fc->scramble_key;
u64 v = (unsigned long) id;
u32 v0 = v;
u32 v1 = v >> 32;
u32 sum = 0;
int i;
for (i = 0; i < 32; i++) {
v0 += ((v1 << 4 ^ v1 >> 5) + v1) ^ (sum + k[sum & 3]);
sum += 0x9E3779B9;
v1 += ((v0 << 4 ^ v0 >> 5) + v0) ^ (sum + k[sum>>11 & 3]);
}
return (u64) v0 + ((u64) v1 << 32);
}
/*
* Check if page is under writeback
*
* This is currently done by walking the list of writepage requests
* for the inode, which can be pretty inefficient.
*/
static bool fuse_page_is_writeback(struct inode *inode, pgoff_t index)
{
struct fuse_conn *fc = get_fuse_conn(inode);
struct fuse_inode *fi = get_fuse_inode(inode);
struct fuse_req *req;
bool found = false;
spin_lock(&fc->lock);
list_for_each_entry(req, &fi->writepages, writepages_entry) {
pgoff_t curr_index;
BUG_ON(req->inode != inode);
curr_index = req->misc.write.in.offset >> PAGE_CACHE_SHIFT;
if (curr_index == index) {
found = true;
break;
}
}
spin_unlock(&fc->lock);
return found;
}
/*
* Wait for page writeback to be completed.
*
* Since fuse doesn't rely on the VM writeback tracking, this has to
* use some other means.
*/
static int fuse_wait_on_page_writeback(struct inode *inode, pgoff_t index)
{
struct fuse_inode *fi = get_fuse_inode(inode);
wait_event(fi->page_waitq, !fuse_page_is_writeback(inode, index));
return 0;
}
static int fuse_flush(struct file *file, fl_owner_t id)
{
struct inode *inode = file->f_path.dentry->d_inode;
struct fuse_conn *fc = get_fuse_conn(inode);
struct fuse_file *ff = file->private_data;
struct fuse_req *req;
struct fuse_flush_in inarg;
int err;
if (is_bad_inode(inode))
return -EIO;
if (fc->no_flush)
return 0;
req = fuse_get_req_nofail(fc, file);
memset(&inarg, 0, sizeof(inarg));
inarg.fh = ff->fh;
inarg.lock_owner = fuse_lock_owner_id(fc, id);
req->in.h.opcode = FUSE_FLUSH;
req->in.h.nodeid = get_node_id(inode);
req->in.numargs = 1;
req->in.args[0].size = sizeof(inarg);
req->in.args[0].value = &inarg;
req->force = 1;
fuse_request_send(fc, req);
err = req->out.h.error;
fuse_put_request(fc, req);
if (err == -ENOSYS) {
fc->no_flush = 1;
err = 0;
}
return err;
}
/*
* Wait for all pending writepages on the inode to finish.
*
* This is currently done by blocking further writes with FUSE_NOWRITE
* and waiting for all sent writes to complete.
*
* This must be called under i_mutex, otherwise the FUSE_NOWRITE usage
* could conflict with truncation.
*/
static void fuse_sync_writes(struct inode *inode)
{
fuse_set_nowrite(inode);
fuse_release_nowrite(inode);
}
int fuse_fsync_common(struct file *file, int datasync, int isdir)
{
struct inode *inode = file->f_mapping->host;
struct fuse_conn *fc = get_fuse_conn(inode);
struct fuse_file *ff = file->private_data;
struct fuse_req *req;
struct fuse_fsync_in inarg;
int err;
if (is_bad_inode(inode))
return -EIO;
if ((!isdir && fc->no_fsync) || (isdir && fc->no_fsyncdir))
return 0;
/*
* Start writeback against all dirty pages of the inode, then
* wait for all outstanding writes, before sending the FSYNC
* request.
*/
err = write_inode_now(inode, 0);
if (err)
return err;
fuse_sync_writes(inode);
req = fuse_get_req(fc);
if (IS_ERR(req))
return PTR_ERR(req);
memset(&inarg, 0, sizeof(inarg));
inarg.fh = ff->fh;
inarg.fsync_flags = datasync ? 1 : 0;
req->in.h.opcode = isdir ? FUSE_FSYNCDIR : FUSE_FSYNC;
req->in.h.nodeid = get_node_id(inode);
req->in.numargs = 1;
req->in.args[0].size = sizeof(inarg);
req->in.args[0].value = &inarg;
fuse_request_send(fc, req);
err = req->out.h.error;
fuse_put_request(fc, req);
if (err == -ENOSYS) {
if (isdir)
fc->no_fsyncdir = 1;
else
fc->no_fsync = 1;
err = 0;
}
return err;
}
static int fuse_fsync(struct file *file, int datasync)
{
return fuse_fsync_common(file, datasync, 0);
}
void fuse_read_fill(struct fuse_req *req, struct file *file, loff_t pos,
size_t count, int opcode)
{
struct fuse_read_in *inarg = &req->misc.read.in;
struct fuse_file *ff = file->private_data;
inarg->fh = ff->fh;
inarg->offset = pos;
inarg->size = count;
inarg->flags = file->f_flags;
req->in.h.opcode = opcode;
req->in.h.nodeid = ff->nodeid;
req->in.numargs = 1;
req->in.args[0].size = sizeof(struct fuse_read_in);
req->in.args[0].value = inarg;
req->out.argvar = 1;
req->out.numargs = 1;
req->out.args[0].size = count;
}
static size_t fuse_send_read(struct fuse_req *req, struct file *file,
loff_t pos, size_t count, fl_owner_t owner)
{
struct fuse_file *ff = file->private_data;
struct fuse_conn *fc = ff->fc;
fuse_read_fill(req, file, pos, count, FUSE_READ);
if (owner != NULL) {
struct fuse_read_in *inarg = &req->misc.read.in;
inarg->read_flags |= FUSE_READ_LOCKOWNER;
inarg->lock_owner = fuse_lock_owner_id(fc, owner);
}
fuse_request_send(fc, req);
return req->out.args[0].size;
}
static void fuse_read_update_size(struct inode *inode, loff_t size,
u64 attr_ver)
{
struct fuse_conn *fc = get_fuse_conn(inode);
struct fuse_inode *fi = get_fuse_inode(inode);
spin_lock(&fc->lock);
if (attr_ver == fi->attr_version && size < inode->i_size) {
fi->attr_version = ++fc->attr_version;
i_size_write(inode, size);
}
spin_unlock(&fc->lock);
}
static int fuse_readpage(struct file *file, struct page *page)
{
struct inode *inode = page->mapping->host;
struct fuse_conn *fc = get_fuse_conn(inode);
struct fuse_req *req;
size_t num_read;
loff_t pos = page_offset(page);
size_t count = PAGE_CACHE_SIZE;
u64 attr_ver;
int err;
err = -EIO;
if (is_bad_inode(inode))
goto out;
/*
* Page writeback can extend beyond the lifetime of the
* page-cache page, so make sure we read a properly synced
* page.
*/
fuse_wait_on_page_writeback(inode, page->index);
req = fuse_get_req(fc);
err = PTR_ERR(req);
if (IS_ERR(req))
goto out;
attr_ver = fuse_get_attr_version(fc);
req->out.page_zeroing = 1;
req->out.argpages = 1;
req->num_pages = 1;
req->pages[0] = page;
num_read = fuse_send_read(req, file, pos, count, NULL);
err = req->out.h.error;
fuse_put_request(fc, req);
if (!err) {
/*
* Short read means EOF. If file size is larger, truncate it
*/
if (num_read < count)
fuse_read_update_size(inode, pos + num_read, attr_ver);
SetPageUptodate(page);
}
fuse_invalidate_attr(inode); /* atime changed */
out:
unlock_page(page);
return err;
}
static void fuse_readpages_end(struct fuse_conn *fc, struct fuse_req *req)
{
int i;
size_t count = req->misc.read.in.size;
size_t num_read = req->out.args[0].size;
struct address_space *mapping = NULL;
for (i = 0; mapping == NULL && i < req->num_pages; i++)
mapping = req->pages[i]->mapping;
if (mapping) {
struct inode *inode = mapping->host;
/*
* Short read means EOF. If file size is larger, truncate it
*/
if (!req->out.h.error && num_read < count) {
loff_t pos;
pos = page_offset(req->pages[0]) + num_read;
fuse_read_update_size(inode, pos,
req->misc.read.attr_ver);
}
fuse_invalidate_attr(inode); /* atime changed */
}
for (i = 0; i < req->num_pages; i++) {
struct page *page = req->pages[i];
if (!req->out.h.error)
SetPageUptodate(page);
else
SetPageError(page);
unlock_page(page);
page_cache_release(page);
}
if (req->ff)
fuse_file_put(req->ff, false);
}
static void fuse_send_readpages(struct fuse_req *req, struct file *file)
{
struct fuse_file *ff = file->private_data;
struct fuse_conn *fc = ff->fc;
loff_t pos = page_offset(req->pages[0]);
size_t count = req->num_pages << PAGE_CACHE_SHIFT;
req->out.argpages = 1;
req->out.page_zeroing = 1;
req->out.page_replace = 1;
fuse_read_fill(req, file, pos, count, FUSE_READ);
req->misc.read.attr_ver = fuse_get_attr_version(fc);
if (fc->async_read) {
req->ff = fuse_file_get(ff);
req->end = fuse_readpages_end;
fuse_request_send_background(fc, req);
} else {
fuse_request_send(fc, req);
fuse_readpages_end(fc, req);
fuse_put_request(fc, req);
}
}
struct fuse_fill_data {
struct fuse_req *req;
struct file *file;
struct inode *inode;
};
static int fuse_readpages_fill(void *_data, struct page *page)
{
struct fuse_fill_data *data = _data;
struct fuse_req *req = data->req;
struct inode *inode = data->inode;
struct fuse_conn *fc = get_fuse_conn(inode);
fuse_wait_on_page_writeback(inode, page->index);
if (req->num_pages &&
(req->num_pages == FUSE_MAX_PAGES_PER_REQ ||
(req->num_pages + 1) * PAGE_CACHE_SIZE > fc->max_read ||
req->pages[req->num_pages - 1]->index + 1 != page->index)) {
fuse_send_readpages(req, data->file);
data->req = req = fuse_get_req(fc);
if (IS_ERR(req)) {
unlock_page(page);
return PTR_ERR(req);
}
}
page_cache_get(page);
req->pages[req->num_pages] = page;
req->num_pages++;
return 0;
}
static int fuse_readpages(struct file *file, struct address_space *mapping,
struct list_head *pages, unsigned nr_pages)
{
struct inode *inode = mapping->host;
struct fuse_conn *fc = get_fuse_conn(inode);
struct fuse_fill_data data;
int err;
err = -EIO;
if (is_bad_inode(inode))
goto out;
data.file = file;
data.inode = inode;
data.req = fuse_get_req(fc);
err = PTR_ERR(data.req);
if (IS_ERR(data.req))
goto out;
err = read_cache_pages(mapping, pages, fuse_readpages_fill, &data);
if (!err) {
if (data.req->num_pages)
fuse_send_readpages(data.req, file);
else
fuse_put_request(fc, data.req);
}
out:
return err;
}
static ssize_t fuse_file_aio_read(struct kiocb *iocb, const struct iovec *iov,
unsigned long nr_segs, loff_t pos)
{
struct inode *inode = iocb->ki_filp->f_mapping->host;
if (pos + iov_length(iov, nr_segs) > i_size_read(inode)) {
int err;
/*
* If trying to read past EOF, make sure the i_size
* attribute is up-to-date.
*/
err = fuse_update_attributes(inode, NULL, iocb->ki_filp, NULL);
if (err)
return err;
}
return generic_file_aio_read(iocb, iov, nr_segs, pos);
}
static void fuse_write_fill(struct fuse_req *req, struct fuse_file *ff,
loff_t pos, size_t count)
{
struct fuse_write_in *inarg = &req->misc.write.in;
struct fuse_write_out *outarg = &req->misc.write.out;
inarg->fh = ff->fh;
inarg->offset = pos;
inarg->size = count;
req->in.h.opcode = FUSE_WRITE;
req->in.h.nodeid = ff->nodeid;
req->in.numargs = 2;
if (ff->fc->minor < 9)
req->in.args[0].size = FUSE_COMPAT_WRITE_IN_SIZE;
else
req->in.args[0].size = sizeof(struct fuse_write_in);
req->in.args[0].value = inarg;
req->in.args[1].size = count;
req->out.numargs = 1;
req->out.args[0].size = sizeof(struct fuse_write_out);
req->out.args[0].value = outarg;
}
static size_t fuse_send_write(struct fuse_req *req, struct file *file,
loff_t pos, size_t count, fl_owner_t owner)
{
struct fuse_file *ff = file->private_data;
struct fuse_conn *fc = ff->fc;
struct fuse_write_in *inarg = &req->misc.write.in;
fuse_write_fill(req, ff, pos, count);
inarg->flags = file->f_flags;
if (owner != NULL) {
inarg->write_flags |= FUSE_WRITE_LOCKOWNER;
inarg->lock_owner = fuse_lock_owner_id(fc, owner);
}
fuse_request_send(fc, req);
return req->misc.write.out.size;
}
static int fuse_write_begin(struct file *file, struct address_space *mapping,
loff_t pos, unsigned len, unsigned flags,
struct page **pagep, void **fsdata)
{
pgoff_t index = pos >> PAGE_CACHE_SHIFT;
*pagep = grab_cache_page_write_begin(mapping, index, flags);
if (!*pagep)
return -ENOMEM;
return 0;
}
void fuse_write_update_size(struct inode *inode, loff_t pos)
{
struct fuse_conn *fc = get_fuse_conn(inode);
struct fuse_inode *fi = get_fuse_inode(inode);
spin_lock(&fc->lock);
fi->attr_version = ++fc->attr_version;
if (pos > inode->i_size)
i_size_write(inode, pos);
spin_unlock(&fc->lock);
}
static int fuse_buffered_write(struct file *file, struct inode *inode,
loff_t pos, unsigned count, struct page *page)
{
int err;
size_t nres;
struct fuse_conn *fc = get_fuse_conn(inode);
unsigned offset = pos & (PAGE_CACHE_SIZE - 1);
struct fuse_req *req;
if (is_bad_inode(inode))
return -EIO;
/*
* Make sure writepages on the same page are not mixed up with
* plain writes.
*/
fuse_wait_on_page_writeback(inode, page->index);
req = fuse_get_req(fc);
if (IS_ERR(req))
return PTR_ERR(req);
req->in.argpages = 1;
req->num_pages = 1;
req->pages[0] = page;
req->page_offset = offset;
nres = fuse_send_write(req, file, pos, count, NULL);
err = req->out.h.error;
fuse_put_request(fc, req);
if (!err && !nres)
err = -EIO;
if (!err) {
pos += nres;
fuse_write_update_size(inode, pos);
if (count == PAGE_CACHE_SIZE)
SetPageUptodate(page);
}
fuse_invalidate_attr(inode);
return err ? err : nres;
}
static int fuse_write_end(struct file *file, struct address_space *mapping,
loff_t pos, unsigned len, unsigned copied,
struct page *page, void *fsdata)
{
struct inode *inode = mapping->host;
int res = 0;
if (copied)
res = fuse_buffered_write(file, inode, pos, copied, page);
unlock_page(page);
page_cache_release(page);
return res;
}
static size_t fuse_send_write_pages(struct fuse_req *req, struct file *file,
struct inode *inode, loff_t pos,
size_t count)
{
size_t res;
unsigned offset;
unsigned i;
for (i = 0; i < req->num_pages; i++)
fuse_wait_on_page_writeback(inode, req->pages[i]->index);
res = fuse_send_write(req, file, pos, count, NULL);
offset = req->page_offset;
count = res;
for (i = 0; i < req->num_pages; i++) {
struct page *page = req->pages[i];
if (!req->out.h.error && !offset && count >= PAGE_CACHE_SIZE)
SetPageUptodate(page);
if (count > PAGE_CACHE_SIZE - offset)
count -= PAGE_CACHE_SIZE - offset;
else
count = 0;
offset = 0;
unlock_page(page);
page_cache_release(page);
}
return res;
}
static ssize_t fuse_fill_write_pages(struct fuse_req *req,
struct address_space *mapping,
struct iov_iter *ii, loff_t pos)
{
struct fuse_conn *fc = get_fuse_conn(mapping->host);
unsigned offset = pos & (PAGE_CACHE_SIZE - 1);
size_t count = 0;
int err;
req->in.argpages = 1;
req->page_offset = offset;
do {
size_t tmp;
struct page *page;
pgoff_t index = pos >> PAGE_CACHE_SHIFT;
size_t bytes = min_t(size_t, PAGE_CACHE_SIZE - offset,
iov_iter_count(ii));
bytes = min_t(size_t, bytes, fc->max_write - count);
again:
err = -EFAULT;
if (iov_iter_fault_in_readable(ii, bytes))
break;
err = -ENOMEM;
page = grab_cache_page_write_begin(mapping, index, 0);
if (!page)
break;
if (mapping_writably_mapped(mapping))
flush_dcache_page(page);
pagefault_disable();
tmp = iov_iter_copy_from_user_atomic(page, ii, offset, bytes);
pagefault_enable();
flush_dcache_page(page);
if (!tmp) {
unlock_page(page);
page_cache_release(page);
bytes = min(bytes, iov_iter_single_seg_count(ii));
goto again;
}
err = 0;
req->pages[req->num_pages] = page;
req->num_pages++;
iov_iter_advance(ii, tmp);
count += tmp;
pos += tmp;
offset += tmp;
if (offset == PAGE_CACHE_SIZE)
offset = 0;
if (!fc->big_writes)
break;
} while (iov_iter_count(ii) && count < fc->max_write &&
req->num_pages < FUSE_MAX_PAGES_PER_REQ && offset == 0);
return count > 0 ? count : err;
}
static ssize_t fuse_perform_write(struct file *file,
struct address_space *mapping,
struct iov_iter *ii, loff_t pos)
{
struct inode *inode = mapping->host;
struct fuse_conn *fc = get_fuse_conn(inode);
int err = 0;
ssize_t res = 0;
if (is_bad_inode(inode))
return -EIO;
do {
struct fuse_req *req;
ssize_t count;
req = fuse_get_req(fc);
if (IS_ERR(req)) {
err = PTR_ERR(req);
break;
}
count = fuse_fill_write_pages(req, mapping, ii, pos);
if (count <= 0) {
err = count;
} else {
size_t num_written;
num_written = fuse_send_write_pages(req, file, inode,
pos, count);
err = req->out.h.error;
if (!err) {
res += num_written;
pos += num_written;
/* break out of the loop on short write */
if (num_written != count)
err = -EIO;
}
}
fuse_put_request(fc, req);
} while (!err && iov_iter_count(ii));
if (res > 0)
fuse_write_update_size(inode, pos);
fuse_invalidate_attr(inode);
return res > 0 ? res : err;
}
static ssize_t fuse_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
unsigned long nr_segs, loff_t pos)
{
struct file *file = iocb->ki_filp;
struct address_space *mapping = file->f_mapping;
size_t count = 0;
ssize_t written = 0;
struct inode *inode = mapping->host;
ssize_t err;
struct iov_iter i;
WARN_ON(iocb->ki_pos != pos);
err = generic_segment_checks(iov, &nr_segs, &count, VERIFY_READ);
if (err)
return err;
mutex_lock(&inode->i_mutex);
vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);
/* We can write back this queue in page reclaim */
current->backing_dev_info = mapping->backing_dev_info;
err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
if (err)
goto out;
if (count == 0)
goto out;
err = file_remove_suid(file);
if (err)
goto out;
file_update_time(file);
iov_iter_init(&i, iov, nr_segs, count, 0);
written = fuse_perform_write(file, mapping, &i, pos);
if (written >= 0)
iocb->ki_pos = pos + written;
out:
current->backing_dev_info = NULL;
mutex_unlock(&inode->i_mutex);
return written ? written : err;
}
static void fuse_release_user_pages(struct fuse_req *req, int write)
{
unsigned i;
for (i = 0; i < req->num_pages; i++) {
struct page *page = req->pages[i];
if (write)
set_page_dirty_lock(page);
put_page(page);
}
}
static int fuse_get_user_pages(struct fuse_req *req, const char __user *buf,
size_t *nbytesp, int write)
{
size_t nbytes = *nbytesp;
unsigned long user_addr = (unsigned long) buf;
unsigned offset = user_addr & ~PAGE_MASK;
int npages;
/* Special case for kernel I/O: can copy directly into the buffer */
if (segment_eq(get_fs(), KERNEL_DS)) {
if (write)
req->in.args[1].value = (void *) user_addr;
else
req->out.args[0].value = (void *) user_addr;
return 0;
}
nbytes = min_t(size_t, nbytes, FUSE_MAX_PAGES_PER_REQ << PAGE_SHIFT);
npages = (nbytes + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
npages = clamp(npages, 1, FUSE_MAX_PAGES_PER_REQ);
npages = get_user_pages_fast(user_addr, npages, !write, req->pages);
if (npages < 0)
return npages;
req->num_pages = npages;
req->page_offset = offset;
if (write)
req->in.argpages = 1;
else
req->out.argpages = 1;
nbytes = (req->num_pages << PAGE_SHIFT) - req->page_offset;
*nbytesp = min(*nbytesp, nbytes);
return 0;
}
ssize_t fuse_direct_io(struct file *file, const char __user *buf,
size_t count, loff_t *ppos, int write)
{
struct fuse_file *ff = file->private_data;
struct fuse_conn *fc = ff->fc;
size_t nmax = write ? fc->max_write : fc->max_read;
loff_t pos = *ppos;
ssize_t res = 0;
struct fuse_req *req;
req = fuse_get_req(fc);
if (IS_ERR(req))
return PTR_ERR(req);
while (count) {
size_t nres;
fl_owner_t owner = current->files;
size_t nbytes = min(count, nmax);
int err = fuse_get_user_pages(req, buf, &nbytes, write);
if (err) {
res = err;
break;
}
if (write)
nres = fuse_send_write(req, file, pos, nbytes, owner);
else
nres = fuse_send_read(req, file, pos, nbytes, owner);
fuse_release_user_pages(req, !write);
if (req->out.h.error) {
if (!res)
res = req->out.h.error;
break;
} else if (nres > nbytes) {
res = -EIO;
break;
}
count -= nres;
res += nres;
pos += nres;
buf += nres;
if (nres != nbytes)
break;
if (count) {
fuse_put_request(fc, req);
req = fuse_get_req(fc);
if (IS_ERR(req))
break;
}
}
if (!IS_ERR(req))
fuse_put_request(fc, req);
if (res > 0)
*ppos = pos;
return res;
}
EXPORT_SYMBOL_GPL(fuse_direct_io);
static ssize_t fuse_direct_read(struct file *file, char __user *buf,
size_t count, loff_t *ppos)
{
ssize_t res;
struct inode *inode = file->f_path.dentry->d_inode;
if (is_bad_inode(inode))
return -EIO;
res = fuse_direct_io(file, buf, count, ppos, 0);
fuse_invalidate_attr(inode);
return res;
}
static ssize_t fuse_direct_write(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
struct inode *inode = file->f_path.dentry->d_inode;
ssize_t res;
if (is_bad_inode(inode))
return -EIO;
/* Don't allow parallel writes to the same file */
mutex_lock(&inode->i_mutex);
res = generic_write_checks(file, ppos, &count, 0);
if (!res) {
res = fuse_direct_io(file, buf, count, ppos, 1);
if (res > 0)
fuse_write_update_size(inode, *ppos);
}
mutex_unlock(&inode->i_mutex);
fuse_invalidate_attr(inode);
return res;
}
static void fuse_writepage_free(struct fuse_conn *fc, struct fuse_req *req)
{
__free_page(req->pages[0]);
fuse_file_put(req->ff, false);
}
static void fuse_writepage_finish(struct fuse_conn *fc, struct fuse_req *req)
{
struct inode *inode = req->inode;
struct fuse_inode *fi = get_fuse_inode(inode);
struct backing_dev_info *bdi = inode->i_mapping->backing_dev_info;
list_del(&req->writepages_entry);
dec_bdi_stat(bdi, BDI_WRITEBACK);
dec_zone_page_state(req->pages[0], NR_WRITEBACK_TEMP);
bdi_writeout_inc(bdi);
wake_up(&fi->page_waitq);
}
/* Called under fc->lock, may release and reacquire it */
static void fuse_send_writepage(struct fuse_conn *fc, struct fuse_req *req)
__releases(fc->lock)
__acquires(fc->lock)
{
struct fuse_inode *fi = get_fuse_inode(req->inode);
loff_t size = i_size_read(req->inode);
struct fuse_write_in *inarg = &req->misc.write.in;
if (!fc->connected)
goto out_free;
if (inarg->offset + PAGE_CACHE_SIZE <= size) {
inarg->size = PAGE_CACHE_SIZE;
} else if (inarg->offset < size) {
inarg->size = size & (PAGE_CACHE_SIZE - 1);
} else {
/* Got truncated off completely */
goto out_free;
}
req->in.args[1].size = inarg->size;
fi->writectr++;
fuse_request_send_background_locked(fc, req);
return;
out_free:
fuse_writepage_finish(fc, req);
spin_unlock(&fc->lock);
fuse_writepage_free(fc, req);
fuse_put_request(fc, req);
spin_lock(&fc->lock);
}
/*
* If fi->writectr is positive (no truncate or fsync going on) send
* all queued writepage requests.
*
* Called with fc->lock
*/
void fuse_flush_writepages(struct inode *inode)
__releases(fc->lock)
__acquires(fc->lock)
{
struct fuse_conn *fc = get_fuse_conn(inode);
struct fuse_inode *fi = get_fuse_inode(inode);
struct fuse_req *req;
while (fi->writectr >= 0 && !list_empty(&fi->queued_writes)) {
req = list_entry(fi->queued_writes.next, struct fuse_req, list);
list_del_init(&req->list);
fuse_send_writepage(fc, req);
}
}
static void fuse_writepage_end(struct fuse_conn *fc, struct fuse_req *req)
{
struct inode *inode = req->inode;
struct fuse_inode *fi = get_fuse_inode(inode);
mapping_set_error(inode->i_mapping, req->out.h.error);
spin_lock(&fc->lock);
fi->writectr--;
fuse_writepage_finish(fc, req);
spin_unlock(&fc->lock);
fuse_writepage_free(fc, req);
}
static int fuse_writepage_locked(struct page *page)
{
struct address_space *mapping = page->mapping;
struct inode *inode = mapping->host;
struct fuse_conn *fc = get_fuse_conn(inode);
struct fuse_inode *fi = get_fuse_inode(inode);
struct fuse_req *req;
struct fuse_file *ff;
struct page *tmp_page;
set_page_writeback(page);
req = fuse_request_alloc_nofs();
if (!req)
goto err;
tmp_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
if (!tmp_page)
goto err_free;
spin_lock(&fc->lock);
BUG_ON(list_empty(&fi->write_files));
ff = list_entry(fi->write_files.next, struct fuse_file, write_entry);
req->ff = fuse_file_get(ff);
spin_unlock(&fc->lock);
fuse_write_fill(req, ff, page_offset(page), 0);
copy_highpage(tmp_page, page);
req->misc.write.in.write_flags |= FUSE_WRITE_CACHE;
req->in.argpages = 1;
req->num_pages = 1;
req->pages[0] = tmp_page;
req->page_offset = 0;
req->end = fuse_writepage_end;
req->inode = inode;
inc_bdi_stat(mapping->backing_dev_info, BDI_WRITEBACK);
inc_zone_page_state(tmp_page, NR_WRITEBACK_TEMP);
end_page_writeback(page);
spin_lock(&fc->lock);
list_add(&req->writepages_entry, &fi->writepages);
list_add_tail(&req->list, &fi->queued_writes);
fuse_flush_writepages(inode);
spin_unlock(&fc->lock);
return 0;
err_free:
fuse_request_free(req);
err:
end_page_writeback(page);
return -ENOMEM;
}
static int fuse_writepage(struct page *page, struct writeback_control *wbc)
{
int err;
err = fuse_writepage_locked(page);
unlock_page(page);
return err;
}
static int fuse_launder_page(struct page *page)
{
int err = 0;
if (clear_page_dirty_for_io(page)) {
struct inode *inode = page->mapping->host;
err = fuse_writepage_locked(page);
if (!err)
fuse_wait_on_page_writeback(inode, page->index);
}
return err;
}
/*
* Write back dirty pages now, because there may not be any suitable
* open files later
*/
static void fuse_vma_close(struct vm_area_struct *vma)
{
filemap_write_and_wait(vma->vm_file->f_mapping);
}
/*
* Wait for writeback against this page to complete before allowing it
* to be marked dirty again, and hence written back again, possibly
* before the previous writepage completed.
*
* Block here, instead of in ->writepage(), so that the userspace fs
* can only block processes actually operating on the filesystem.
*
* Otherwise unprivileged userspace fs would be able to block
* unrelated:
*
* - page migration
* - sync(2)
* - try_to_free_pages() with order > PAGE_ALLOC_COSTLY_ORDER
*/
static int fuse_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
{
struct page *page = vmf->page;
/*
* Don't use page->mapping as it may become NULL from a
* concurrent truncate.
*/
struct inode *inode = vma->vm_file->f_mapping->host;
fuse_wait_on_page_writeback(inode, page->index);
return 0;
}
static const struct vm_operations_struct fuse_file_vm_ops = {
.close = fuse_vma_close,
.fault = filemap_fault,
.page_mkwrite = fuse_page_mkwrite,
};
static int fuse_file_mmap(struct file *file, struct vm_area_struct *vma)
{
if ((vma->vm_flags & VM_SHARED) && (vma->vm_flags & VM_MAYWRITE)) {
struct inode *inode = file->f_dentry->d_inode;
struct fuse_conn *fc = get_fuse_conn(inode);
struct fuse_inode *fi = get_fuse_inode(inode);
struct fuse_file *ff = file->private_data;
/*
* file may be written through mmap, so chain it onto the
* inodes's write_file list
*/
spin_lock(&fc->lock);
if (list_empty(&ff->write_entry))
list_add(&ff->write_entry, &fi->write_files);
spin_unlock(&fc->lock);
}
file_accessed(file);
vma->vm_ops = &fuse_file_vm_ops;
return 0;
}
static int fuse_direct_mmap(struct file *file, struct vm_area_struct *vma)
{
/* Can't provide the coherency needed for MAP_SHARED */
if (vma->vm_flags & VM_MAYSHARE)
return -ENODEV;
invalidate_inode_pages2(file->f_mapping);
return generic_file_mmap(file, vma);
}
static int convert_fuse_file_lock(const struct fuse_file_lock *ffl,
struct file_lock *fl)
{
switch (ffl->type) {
case F_UNLCK:
break;
case F_RDLCK:
case F_WRLCK:
if (ffl->start > OFFSET_MAX || ffl->end > OFFSET_MAX ||
ffl->end < ffl->start)
return -EIO;
fl->fl_start = ffl->start;
fl->fl_end = ffl->end;
fl->fl_pid = ffl->pid;
break;
default:
return -EIO;
}
fl->fl_type = ffl->type;
return 0;
}
static void fuse_lk_fill(struct fuse_req *req, struct file *file,
const struct file_lock *fl, int opcode, pid_t pid,
int flock)
{
struct inode *inode = file->f_path.dentry->d_inode;
struct fuse_conn *fc = get_fuse_conn(inode);
struct fuse_file *ff = file->private_data;
struct fuse_lk_in *arg = &req->misc.lk_in;
arg->fh = ff->fh;
arg->owner = fuse_lock_owner_id(fc, fl->fl_owner);
arg->lk.start = fl->fl_start;
arg->lk.end = fl->fl_end;
arg->lk.type = fl->fl_type;
arg->lk.pid = pid;
if (flock)
arg->lk_flags |= FUSE_LK_FLOCK;
req->in.h.opcode = opcode;
req->in.h.nodeid = get_node_id(inode);
req->in.numargs = 1;
req->in.args[0].size = sizeof(*arg);
req->in.args[0].value = arg;
}
static int fuse_getlk(struct file *file, struct file_lock *fl)
{
struct inode *inode = file->f_path.dentry->d_inode;
struct fuse_conn *fc = get_fuse_conn(inode);
struct fuse_req *req;
struct fuse_lk_out outarg;
int err;
req = fuse_get_req(fc);
if (IS_ERR(req))
return PTR_ERR(req);
fuse_lk_fill(req, file, fl, FUSE_GETLK, 0, 0);
req->out.numargs = 1;
req->out.args[0].size = sizeof(outarg);
req->out.args[0].value = &outarg;
fuse_request_send(fc, req);
err = req->out.h.error;
fuse_put_request(fc, req);
if (!err)
err = convert_fuse_file_lock(&outarg.lk, fl);
return err;
}
static int fuse_setlk(struct file *file, struct file_lock *fl, int flock)
{
struct inode *inode = file->f_path.dentry->d_inode;
struct fuse_conn *fc = get_fuse_conn(inode);
struct fuse_req *req;
int opcode = (fl->fl_flags & FL_SLEEP) ? FUSE_SETLKW : FUSE_SETLK;
pid_t pid = fl->fl_type != F_UNLCK ? current->tgid : 0;
int err;
if (fl->fl_lmops && fl->fl_lmops->fl_grant) {
/* NLM needs asynchronous locks, which we don't support yet */
return -ENOLCK;
}
/* Unlock on close is handled by the flush method */
if (fl->fl_flags & FL_CLOSE)
return 0;
req = fuse_get_req(fc);
if (IS_ERR(req))
return PTR_ERR(req);
fuse_lk_fill(req, file, fl, opcode, pid, flock);
fuse_request_send(fc, req);
err = req->out.h.error;
/* locking is restartable */
if (err == -EINTR)
err = -ERESTARTSYS;
fuse_put_request(fc, req);
return err;
}
static int fuse_file_lock(struct file *file, int cmd, struct file_lock *fl)
{
struct inode *inode = file->f_path.dentry->d_inode;
struct fuse_conn *fc = get_fuse_conn(inode);
int err;
if (cmd == F_CANCELLK) {
err = 0;
} else if (cmd == F_GETLK) {
if (fc->no_lock) {
posix_test_lock(file, fl);
err = 0;
} else
err = fuse_getlk(file, fl);
} else {
if (fc->no_lock)
err = posix_lock_file(file, fl, NULL);
else
err = fuse_setlk(file, fl, 0);
}
return err;
}
static int fuse_file_flock(struct file *file, int cmd, struct file_lock *fl)
{
struct inode *inode = file->f_path.dentry->d_inode;
struct fuse_conn *fc = get_fuse_conn(inode);
int err;
if (fc->no_lock) {
err = flock_lock_file_wait(file, fl);
} else {
/* emulate flock with POSIX locks */
fl->fl_owner = (fl_owner_t) file;
err = fuse_setlk(file, fl, 1);
}
return err;
}
static sector_t fuse_bmap(struct address_space *mapping, sector_t block)
{
struct inode *inode = mapping->host;
struct fuse_conn *fc = get_fuse_conn(inode);
struct fuse_req *req;
struct fuse_bmap_in inarg;
struct fuse_bmap_out outarg;
int err;
if (!inode->i_sb->s_bdev || fc->no_bmap)
return 0;
req = fuse_get_req(fc);
if (IS_ERR(req))
return 0;
memset(&inarg, 0, sizeof(inarg));
inarg.block = block;
inarg.blocksize = inode->i_sb->s_blocksize;
req->in.h.opcode = FUSE_BMAP;
req->in.h.nodeid = get_node_id(inode);
req->in.numargs = 1;
req->in.args[0].size = sizeof(inarg);
req->in.args[0].value = &inarg;
req->out.numargs = 1;
req->out.args[0].size = sizeof(outarg);
req->out.args[0].value = &outarg;
fuse_request_send(fc, req);
err = req->out.h.error;
fuse_put_request(fc, req);
if (err == -ENOSYS)
fc->no_bmap = 1;
return err ? 0 : outarg.block;
}
static loff_t fuse_file_llseek(struct file *file, loff_t offset, int origin)
{
loff_t retval;
struct inode *inode = file->f_path.dentry->d_inode;
mutex_lock(&inode->i_mutex);
switch (origin) {
case SEEK_END:
retval = fuse_update_attributes(inode, NULL, file, NULL);
if (retval)
goto exit;
offset += i_size_read(inode);
break;
case SEEK_CUR:
offset += file->f_pos;
}
retval = -EINVAL;
if (offset >= 0 && offset <= inode->i_sb->s_maxbytes) {
if (offset != file->f_pos) {
file->f_pos = offset;
file->f_version = 0;
}
retval = offset;
}
exit:
mutex_unlock(&inode->i_mutex);
return retval;
}
static int fuse_ioctl_copy_user(struct page **pages, struct iovec *iov,
unsigned int nr_segs, size_t bytes, bool to_user)
{
struct iov_iter ii;
int page_idx = 0;
if (!bytes)
return 0;
iov_iter_init(&ii, iov, nr_segs, bytes, 0);
while (iov_iter_count(&ii)) {
struct page *page = pages[page_idx++];
size_t todo = min_t(size_t, PAGE_SIZE, iov_iter_count(&ii));
void *kaddr;
kaddr = kmap(page);
while (todo) {
char __user *uaddr = ii.iov->iov_base + ii.iov_offset;
size_t iov_len = ii.iov->iov_len - ii.iov_offset;
size_t copy = min(todo, iov_len);
size_t left;
if (!to_user)
left = copy_from_user(kaddr, uaddr, copy);
else
left = copy_to_user(uaddr, kaddr, copy);
if (unlikely(left))
return -EFAULT;
iov_iter_advance(&ii, copy);
todo -= copy;
kaddr += copy;
}
kunmap(page);
}
return 0;
}
/*
* CUSE servers compiled on 32bit broke on 64bit kernels because the
* ABI was defined to be 'struct iovec' which is different on 32bit
* and 64bit. Fortunately we can determine which structure the server
* used from the size of the reply.
*/
static int fuse_copy_ioctl_iovec_old(struct iovec *dst, void *src,
size_t transferred, unsigned count,
bool is_compat)
{
#ifdef CONFIG_COMPAT
if (count * sizeof(struct compat_iovec) == transferred) {
struct compat_iovec *ciov = src;
unsigned i;
/*
* With this interface a 32bit server cannot support
* non-compat (i.e. ones coming from 64bit apps) ioctl
* requests
*/
if (!is_compat)
return -EINVAL;
for (i = 0; i < count; i++) {
dst[i].iov_base = compat_ptr(ciov[i].iov_base);
dst[i].iov_len = ciov[i].iov_len;
}
return 0;
}
#endif
if (count * sizeof(struct iovec) != transferred)
return -EIO;
memcpy(dst, src, transferred);
return 0;
}
/* Make sure iov_length() won't overflow */
static int fuse_verify_ioctl_iov(struct iovec *iov, size_t count)
{
size_t n;
u32 max = FUSE_MAX_PAGES_PER_REQ << PAGE_SHIFT;
for (n = 0; n < count; n++, iov++) {
if (iov->iov_len > (size_t) max)
return -ENOMEM;
max -= iov->iov_len;
}
return 0;
}
static int fuse_copy_ioctl_iovec(struct fuse_conn *fc, struct iovec *dst,
void *src, size_t transferred, unsigned count,
bool is_compat)
{
unsigned i;
struct fuse_ioctl_iovec *fiov = src;
if (fc->minor < 16) {
return fuse_copy_ioctl_iovec_old(dst, src, transferred,
count, is_compat);
}
if (count * sizeof(struct fuse_ioctl_iovec) != transferred)
return -EIO;
for (i = 0; i < count; i++) {
/* Did the server supply an inappropriate value? */
if (fiov[i].base != (unsigned long) fiov[i].base ||
fiov[i].len != (unsigned long) fiov[i].len)
return -EIO;
dst[i].iov_base = (void __user *) (unsigned long) fiov[i].base;
dst[i].iov_len = (size_t) fiov[i].len;
#ifdef CONFIG_COMPAT
if (is_compat &&
(ptr_to_compat(dst[i].iov_base) != fiov[i].base ||
(compat_size_t) dst[i].iov_len != fiov[i].len))
return -EIO;
#endif
}
return 0;
}
/*
* For ioctls, there is no generic way to determine how much memory
* needs to be read and/or written. Furthermore, ioctls are allowed
* to dereference the passed pointer, so the parameter requires deep
* copying but FUSE has no idea whatsoever about what to copy in or
* out.
*
* This is solved by allowing FUSE server to retry ioctl with
* necessary in/out iovecs. Let's assume the ioctl implementation
* needs to read in the following structure.
*
* struct a {
* char *buf;
* size_t buflen;
* }
*
* On the first callout to FUSE server, inarg->in_size and
* inarg->out_size will be NULL; then, the server completes the ioctl
* with FUSE_IOCTL_RETRY set in out->flags, out->in_iovs set to 1 and
* the actual iov array to
*
* { { .iov_base = inarg.arg, .iov_len = sizeof(struct a) } }
*
* which tells FUSE to copy in the requested area and retry the ioctl.
* On the second round, the server has access to the structure and
* from that it can tell what to look for next, so on the invocation,
* it sets FUSE_IOCTL_RETRY, out->in_iovs to 2 and iov array to
*
* { { .iov_base = inarg.arg, .iov_len = sizeof(struct a) },
* { .iov_base = a.buf, .iov_len = a.buflen } }
*
* FUSE will copy both struct a and the pointed buffer from the
* process doing the ioctl and retry ioctl with both struct a and the
* buffer.
*
* This time, FUSE server has everything it needs and completes ioctl
* without FUSE_IOCTL_RETRY which finishes the ioctl call.
*
* Copying data out works the same way.
*
* Note that if FUSE_IOCTL_UNRESTRICTED is clear, the kernel
* automatically initializes in and out iovs by decoding @cmd with
* _IOC_* macros and the server is not allowed to request RETRY. This
* limits ioctl data transfers to well-formed ioctls and is the forced
* behavior for all FUSE servers.
*/
long fuse_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg,
unsigned int flags)
{
struct fuse_file *ff = file->private_data;
struct fuse_conn *fc = ff->fc;
struct fuse_ioctl_in inarg = {
.fh = ff->fh,
.cmd = cmd,
.arg = arg,
.flags = flags
};
struct fuse_ioctl_out outarg;
struct fuse_req *req = NULL;
struct page **pages = NULL;
struct iovec *iov_page = NULL;
struct iovec *in_iov = NULL, *out_iov = NULL;
unsigned int in_iovs = 0, out_iovs = 0, num_pages = 0, max_pages;
size_t in_size, out_size, transferred;
int err;
#if BITS_PER_LONG == 32
inarg.flags |= FUSE_IOCTL_32BIT;
#else
if (flags & FUSE_IOCTL_COMPAT)
inarg.flags |= FUSE_IOCTL_32BIT;
#endif
/* assume all the iovs returned by client always fits in a page */
BUILD_BUG_ON(sizeof(struct fuse_ioctl_iovec) * FUSE_IOCTL_MAX_IOV > PAGE_SIZE);
err = -ENOMEM;
pages = kzalloc(sizeof(pages[0]) * FUSE_MAX_PAGES_PER_REQ, GFP_KERNEL);
iov_page = (struct iovec *) __get_free_page(GFP_KERNEL);
if (!pages || !iov_page)
goto out;
/*
* If restricted, initialize IO parameters as encoded in @cmd.
* RETRY from server is not allowed.
*/
if (!(flags & FUSE_IOCTL_UNRESTRICTED)) {
struct iovec *iov = iov_page;
iov->iov_base = (void __user *)arg;
iov->iov_len = _IOC_SIZE(cmd);
if (_IOC_DIR(cmd) & _IOC_WRITE) {
in_iov = iov;
in_iovs = 1;
}
if (_IOC_DIR(cmd) & _IOC_READ) {
out_iov = iov;
out_iovs = 1;
}
}
retry:
inarg.in_size = in_size = iov_length(in_iov, in_iovs);
inarg.out_size = out_size = iov_length(out_iov, out_iovs);
/*
* Out data can be used either for actual out data or iovs,
* make sure there always is at least one page.
*/
out_size = max_t(size_t, out_size, PAGE_SIZE);
max_pages = DIV_ROUND_UP(max(in_size, out_size), PAGE_SIZE);
/* make sure there are enough buffer pages and init request with them */
err = -ENOMEM;
if (max_pages > FUSE_MAX_PAGES_PER_REQ)
goto out;
while (num_pages < max_pages) {
pages[num_pages] = alloc_page(GFP_KERNEL | __GFP_HIGHMEM);
if (!pages[num_pages])
goto out;
num_pages++;
}
req = fuse_get_req(fc);
if (IS_ERR(req)) {
err = PTR_ERR(req);
req = NULL;
goto out;
}
memcpy(req->pages, pages, sizeof(req->pages[0]) * num_pages);
req->num_pages = num_pages;
/* okay, let's send it to the client */
req->in.h.opcode = FUSE_IOCTL;
req->in.h.nodeid = ff->nodeid;
req->in.numargs = 1;
req->in.args[0].size = sizeof(inarg);
req->in.args[0].value = &inarg;
if (in_size) {
req->in.numargs++;
req->in.args[1].size = in_size;
req->in.argpages = 1;
err = fuse_ioctl_copy_user(pages, in_iov, in_iovs, in_size,
false);
if (err)
goto out;
}
req->out.numargs = 2;
req->out.args[0].size = sizeof(outarg);
req->out.args[0].value = &outarg;
req->out.args[1].size = out_size;
req->out.argpages = 1;
req->out.argvar = 1;
fuse_request_send(fc, req);
err = req->out.h.error;
transferred = req->out.args[1].size;
fuse_put_request(fc, req);
req = NULL;
if (err)
goto out;
/* did it ask for retry? */
if (outarg.flags & FUSE_IOCTL_RETRY) {
void *vaddr;
/* no retry if in restricted mode */
err = -EIO;
if (!(flags & FUSE_IOCTL_UNRESTRICTED))
goto out;
in_iovs = outarg.in_iovs;
out_iovs = outarg.out_iovs;
/*
* Make sure things are in boundary, separate checks
* are to protect against overflow.
*/
err = -ENOMEM;
if (in_iovs > FUSE_IOCTL_MAX_IOV ||
out_iovs > FUSE_IOCTL_MAX_IOV ||
in_iovs + out_iovs > FUSE_IOCTL_MAX_IOV)
goto out;
vaddr = kmap_atomic(pages[0], KM_USER0);
err = fuse_copy_ioctl_iovec(fc, iov_page, vaddr,
transferred, in_iovs + out_iovs,
(flags & FUSE_IOCTL_COMPAT) != 0);
kunmap_atomic(vaddr, KM_USER0);
if (err)
goto out;
in_iov = iov_page;
out_iov = in_iov + in_iovs;
err = fuse_verify_ioctl_iov(in_iov, in_iovs);
if (err)
goto out;
err = fuse_verify_ioctl_iov(out_iov, out_iovs);
if (err)
goto out;
goto retry;
}
err = -EIO;
if (transferred > inarg.out_size)
goto out;
err = fuse_ioctl_copy_user(pages, out_iov, out_iovs, transferred, true);
out:
if (req)
fuse_put_request(fc, req);
free_page((unsigned long) iov_page);
while (num_pages)
__free_page(pages[--num_pages]);
kfree(pages);
return err ? err : outarg.result;
}
EXPORT_SYMBOL_GPL(fuse_do_ioctl);
static long fuse_file_ioctl_common(struct file *file, unsigned int cmd,
unsigned long arg, unsigned int flags)
{
struct inode *inode = file->f_dentry->d_inode;
struct fuse_conn *fc = get_fuse_conn(inode);
if (!fuse_allow_task(fc, current))
return -EACCES;
if (is_bad_inode(inode))
return -EIO;
return fuse_do_ioctl(file, cmd, arg, flags);
}
static long fuse_file_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
return fuse_file_ioctl_common(file, cmd, arg, 0);
}
static long fuse_file_compat_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
return fuse_file_ioctl_common(file, cmd, arg, FUSE_IOCTL_COMPAT);
}
/*
* All files which have been polled are linked to RB tree
* fuse_conn->polled_files which is indexed by kh. Walk the tree and
* find the matching one.
*/
static struct rb_node **fuse_find_polled_node(struct fuse_conn *fc, u64 kh,
struct rb_node **parent_out)
{
struct rb_node **link = &fc->polled_files.rb_node;
struct rb_node *last = NULL;
while (*link) {
struct fuse_file *ff;
last = *link;
ff = rb_entry(last, struct fuse_file, polled_node);
if (kh < ff->kh)
link = &last->rb_left;
else if (kh > ff->kh)
link = &last->rb_right;
else
return link;
}
if (parent_out)
*parent_out = last;
return link;
}
/*
* The file is about to be polled. Make sure it's on the polled_files
* RB tree. Note that files once added to the polled_files tree are
* not removed before the file is released. This is because a file
* polled once is likely to be polled again.
*/
static void fuse_register_polled_file(struct fuse_conn *fc,
struct fuse_file *ff)
{
spin_lock(&fc->lock);
if (RB_EMPTY_NODE(&ff->polled_node)) {
struct rb_node **link, *parent;
link = fuse_find_polled_node(fc, ff->kh, &parent);
BUG_ON(*link);
rb_link_node(&ff->polled_node, parent, link);
rb_insert_color(&ff->polled_node, &fc->polled_files);
}
spin_unlock(&fc->lock);
}
unsigned fuse_file_poll(struct file *file, poll_table *wait)
{
struct fuse_file *ff = file->private_data;
struct fuse_conn *fc = ff->fc;
struct fuse_poll_in inarg = { .fh = ff->fh, .kh = ff->kh };
struct fuse_poll_out outarg;
struct fuse_req *req;
int err;
if (fc->no_poll)
return DEFAULT_POLLMASK;
poll_wait(file, &ff->poll_wait, wait);
/*
* Ask for notification iff there's someone waiting for it.
* The client may ignore the flag and always notify.
*/
if (waitqueue_active(&ff->poll_wait)) {
inarg.flags |= FUSE_POLL_SCHEDULE_NOTIFY;
fuse_register_polled_file(fc, ff);
}
req = fuse_get_req(fc);
if (IS_ERR(req))
return POLLERR;
req->in.h.opcode = FUSE_POLL;
req->in.h.nodeid = ff->nodeid;
req->in.numargs = 1;
req->in.args[0].size = sizeof(inarg);
req->in.args[0].value = &inarg;
req->out.numargs = 1;
req->out.args[0].size = sizeof(outarg);
req->out.args[0].value = &outarg;
fuse_request_send(fc, req);
err = req->out.h.error;
fuse_put_request(fc, req);
if (!err)
return outarg.revents;
if (err == -ENOSYS) {
fc->no_poll = 1;
return DEFAULT_POLLMASK;
}
return POLLERR;
}
EXPORT_SYMBOL_GPL(fuse_file_poll);
/*
* This is called from fuse_handle_notify() on FUSE_NOTIFY_POLL and
* wakes up the poll waiters.
*/
int fuse_notify_poll_wakeup(struct fuse_conn *fc,
struct fuse_notify_poll_wakeup_out *outarg)
{
u64 kh = outarg->kh;
struct rb_node **link;
spin_lock(&fc->lock);
link = fuse_find_polled_node(fc, kh, NULL);
if (*link) {
struct fuse_file *ff;
ff = rb_entry(*link, struct fuse_file, polled_node);
wake_up_interruptible_sync(&ff->poll_wait);
}
spin_unlock(&fc->lock);
return 0;
}
static const struct file_operations fuse_file_operations = {
.llseek = fuse_file_llseek,
.read = do_sync_read,
.aio_read = fuse_file_aio_read,
.write = do_sync_write,
.aio_write = fuse_file_aio_write,
.mmap = fuse_file_mmap,
.open = fuse_open,
.flush = fuse_flush,
.release = fuse_release,
.fsync = fuse_fsync,
.lock = fuse_file_lock,
.flock = fuse_file_flock,
.splice_read = generic_file_splice_read,
.unlocked_ioctl = fuse_file_ioctl,
.compat_ioctl = fuse_file_compat_ioctl,
.poll = fuse_file_poll,
};
static const struct file_operations fuse_direct_io_file_operations = {
.llseek = fuse_file_llseek,
.read = fuse_direct_read,
.write = fuse_direct_write,
.mmap = fuse_direct_mmap,
.open = fuse_open,
.flush = fuse_flush,
.release = fuse_release,
.fsync = fuse_fsync,
.lock = fuse_file_lock,
.flock = fuse_file_flock,
.unlocked_ioctl = fuse_file_ioctl,
.compat_ioctl = fuse_file_compat_ioctl,
.poll = fuse_file_poll,
/* no splice_read */
};
static const struct address_space_operations fuse_file_aops = {
.readpage = fuse_readpage,
.writepage = fuse_writepage,
.launder_page = fuse_launder_page,
.write_begin = fuse_write_begin,
.write_end = fuse_write_end,
.readpages = fuse_readpages,
.set_page_dirty = __set_page_dirty_nobuffers,
.bmap = fuse_bmap,
};
void fuse_init_file_inode(struct inode *inode)
{
inode->i_fop = &fuse_file_operations;
inode->i_data.a_ops = &fuse_file_aops;
}