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OpenCloudOS-Kernel/fs/fuse/file.c

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/*
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/sched/signal.h>
#include <linux/module.h>
#include <linux/compat.h>
#include <linux/swap.h>
#include <linux/falloc.h>
#include <linux/uio.h>
static struct page **fuse_pages_alloc(unsigned int npages, gfp_t flags,
struct fuse_page_desc **desc)
{
struct page **pages;
pages = kzalloc(npages * (sizeof(struct page *) +
sizeof(struct fuse_page_desc)), flags);
*desc = (void *) (pages + npages);
return pages;
}
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;
FUSE_ARGS(args);
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;
args.opcode = opcode;
args.nodeid = nodeid;
args.in_numargs = 1;
args.in_args[0].size = sizeof(inarg);
args.in_args[0].value = &inarg;
args.out_numargs = 1;
args.out_args[0].size = sizeof(*outargp);
args.out_args[0].value = outargp;
return fuse_simple_request(fc, &args);
}
struct fuse_release_args {
struct fuse_args args;
struct fuse_release_in inarg;
struct inode *inode;
};
struct fuse_file *fuse_file_alloc(struct fuse_conn *fc)
{
struct fuse_file *ff;
ff = kzalloc(sizeof(struct fuse_file), GFP_KERNEL_ACCOUNT);
if (unlikely(!ff))
return NULL;
ff->fc = fc;
ff->release_args = kzalloc(sizeof(*ff->release_args),
GFP_KERNEL_ACCOUNT);
if (!ff->release_args) {
kfree(ff);
return NULL;
}
INIT_LIST_HEAD(&ff->write_entry);
mutex_init(&ff->readdir.lock);
refcount_set(&ff->count, 1);
RB_CLEAR_NODE(&ff->polled_node);
init_waitqueue_head(&ff->poll_wait);
ff->kh = atomic64_inc_return(&fc->khctr);
return ff;
}
void fuse_file_free(struct fuse_file *ff)
{
kfree(ff->release_args);
mutex_destroy(&ff->readdir.lock);
kfree(ff);
}
static struct fuse_file *fuse_file_get(struct fuse_file *ff)
{
refcount_inc(&ff->count);
return ff;
}
static void fuse_release_end(struct fuse_conn *fc, struct fuse_args *args,
int error)
{
struct fuse_release_args *ra = container_of(args, typeof(*ra), args);
iput(ra->inode);
kfree(ra);
}
static void fuse_file_put(struct fuse_file *ff, bool sync, bool isdir)
{
if (refcount_dec_and_test(&ff->count)) {
struct fuse_args *args = &ff->release_args->args;
if (isdir ? ff->fc->no_opendir : ff->fc->no_open) {
/* Do nothing when client does not implement 'open' */
fuse_release_end(ff->fc, args, 0);
} else if (sync) {
fuse_simple_request(ff->fc, args);
fuse_release_end(ff->fc, args, 0);
} else {
args->end = fuse_release_end;
if (fuse_simple_background(ff->fc, args,
GFP_KERNEL | __GFP_NOFAIL))
fuse_release_end(ff->fc, args, -ENOTCONN);
}
kfree(ff);
}
}
int fuse_do_open(struct fuse_conn *fc, u64 nodeid, struct file *file,
bool isdir)
{
struct fuse_file *ff;
int opcode = isdir ? FUSE_OPENDIR : FUSE_OPEN;
ff = fuse_file_alloc(fc);
if (!ff)
return -ENOMEM;
ff->fh = 0;
/* Default for no-open */
ff->open_flags = FOPEN_KEEP_CACHE | (isdir ? FOPEN_CACHE_DIR : 0);
if (isdir ? !fc->no_opendir : !fc->no_open) {
struct fuse_open_out outarg;
int err;
err = fuse_send_open(fc, nodeid, file, opcode, &outarg);
if (!err) {
ff->fh = outarg.fh;
ff->open_flags = outarg.open_flags;
} else if (err != -ENOSYS) {
fuse_file_free(ff);
return err;
} else {
if (isdir)
fc->no_opendir = 1;
else
fc->no_open = 1;
}
}
if (isdir)
ff->open_flags &= ~FOPEN_DIRECT_IO;
ff->nodeid = nodeid;
file->private_data = ff;
return 0;
}
EXPORT_SYMBOL_GPL(fuse_do_open);
static void fuse_link_write_file(struct file *file)
{
struct inode *inode = file_inode(file);
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(&fi->lock);
if (list_empty(&ff->write_entry))
list_add(&ff->write_entry, &fi->write_files);
spin_unlock(&fi->lock);
}
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_KEEP_CACHE))
invalidate_inode_pages2(inode->i_mapping);
if (ff->open_flags & FOPEN_STREAM)
stream_open(inode, file);
else 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(&fi->lock);
fi->attr_version = atomic64_inc_return(&fc->attr_version);
i_size_write(inode, 0);
spin_unlock(&fi->lock);
fuse_invalidate_attr(inode);
if (fc->writeback_cache)
file_update_time(file);
}
if ((file->f_mode & FMODE_WRITE) && fc->writeback_cache)
fuse_link_write_file(file);
}
int fuse_open_common(struct inode *inode, struct file *file, bool isdir)
{
struct fuse_conn *fc = get_fuse_conn(inode);
int err;
bool is_wb_truncate = (file->f_flags & O_TRUNC) &&
fc->atomic_o_trunc &&
fc->writeback_cache;
err = generic_file_open(inode, file);
if (err)
return err;
if (is_wb_truncate) {
inode_lock(inode);
fuse_set_nowrite(inode);
}
err = fuse_do_open(fc, get_node_id(inode), file, isdir);
if (!err)
fuse_finish_open(inode, file);
if (is_wb_truncate) {
fuse_release_nowrite(inode);
inode_unlock(inode);
}
return err;
}
static void fuse_prepare_release(struct fuse_inode *fi, struct fuse_file *ff,
int flags, int opcode)
{
struct fuse_conn *fc = ff->fc;
struct fuse_release_args *ra = ff->release_args;
/* Inode is NULL on error path of fuse_create_open() */
if (likely(fi)) {
spin_lock(&fi->lock);
list_del(&ff->write_entry);
spin_unlock(&fi->lock);
}
spin_lock(&fc->lock);
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);
ra->inarg.fh = ff->fh;
ra->inarg.flags = flags;
ra->args.in_numargs = 1;
ra->args.in_args[0].size = sizeof(struct fuse_release_in);
ra->args.in_args[0].value = &ra->inarg;
ra->args.opcode = opcode;
ra->args.nodeid = ff->nodeid;
ra->args.force = true;
ra->args.nocreds = true;
}
void fuse_release_common(struct file *file, bool isdir)
{
struct fuse_inode *fi = get_fuse_inode(file_inode(file));
struct fuse_file *ff = file->private_data;
struct fuse_release_args *ra = ff->release_args;
int opcode = isdir ? FUSE_RELEASEDIR : FUSE_RELEASE;
fuse_prepare_release(fi, ff, file->f_flags, opcode);
if (ff->flock) {
ra->inarg.release_flags |= FUSE_RELEASE_FLOCK_UNLOCK;
ra->inarg.lock_owner = fuse_lock_owner_id(ff->fc,
(fl_owner_t) file);
}
/* Hold inode until release is finished */
ra->inode = igrab(file_inode(file));
/*
* 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, isdir);
}
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)
{
struct fuse_conn *fc = get_fuse_conn(inode);
/* see fuse_vma_close() for !writeback_cache case */
if (fc->writeback_cache)
write_inode_now(inode, 1);
fuse_release_common(file, false);
/* return value is ignored by VFS */
return 0;
}
void fuse_sync_release(struct fuse_inode *fi, struct fuse_file *ff, int flags)
{
WARN_ON(refcount_read(&ff->count) > 1);
fuse_prepare_release(fi, ff, flags, FUSE_RELEASE);
/*
* iput(NULL) is a no-op and since the refcount is 1 and everything's
* synchronous, we are fine with not doing igrab() here"
*/
fuse_file_put(ff, true, false);
}
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);
}
struct fuse_writepage_args {
struct fuse_io_args ia;
struct list_head writepages_entry;
struct list_head queue_entry;
struct fuse_writepage_args *next;
struct inode *inode;
};
static struct fuse_writepage_args *fuse_find_writeback(struct fuse_inode *fi,
pgoff_t idx_from, pgoff_t idx_to)
{
struct fuse_writepage_args *wpa;
list_for_each_entry(wpa, &fi->writepages, writepages_entry) {
pgoff_t curr_index;
WARN_ON(get_fuse_inode(wpa->inode) != fi);
curr_index = wpa->ia.write.in.offset >> PAGE_SHIFT;
if (idx_from < curr_index + wpa->ia.ap.num_pages &&
curr_index <= idx_to) {
return wpa;
}
}
return NULL;
}
/*
* Check if any page in a range 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_range_is_writeback(struct inode *inode, pgoff_t idx_from,
pgoff_t idx_to)
{
struct fuse_inode *fi = get_fuse_inode(inode);
bool found;
spin_lock(&fi->lock);
found = fuse_find_writeback(fi, idx_from, idx_to);
spin_unlock(&fi->lock);
return found;
}
static inline bool fuse_page_is_writeback(struct inode *inode, pgoff_t index)
{
return fuse_range_is_writeback(inode, index, index);
}
/*
* 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 void 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));
}
/*
* 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);
}
static int fuse_flush(struct file *file, fl_owner_t id)
{
struct inode *inode = file_inode(file);
struct fuse_conn *fc = get_fuse_conn(inode);
struct fuse_file *ff = file->private_data;
struct fuse_flush_in inarg;
FUSE_ARGS(args);
int err;
if (is_bad_inode(inode))
return -EIO;
if (fc->no_flush)
return 0;
err = write_inode_now(inode, 1);
if (err)
return err;
inode_lock(inode);
fuse_sync_writes(inode);
inode_unlock(inode);
err = filemap_check_errors(file->f_mapping);
if (err)
return err;
memset(&inarg, 0, sizeof(inarg));
inarg.fh = ff->fh;
inarg.lock_owner = fuse_lock_owner_id(fc, id);
args.opcode = FUSE_FLUSH;
args.nodeid = get_node_id(inode);
args.in_numargs = 1;
args.in_args[0].size = sizeof(inarg);
args.in_args[0].value = &inarg;
args.force = true;
err = fuse_simple_request(fc, &args);
if (err == -ENOSYS) {
fc->no_flush = 1;
err = 0;
}
return err;
}
int fuse_fsync_common(struct file *file, loff_t start, loff_t end,
int datasync, int opcode)
{
struct inode *inode = file->f_mapping->host;
struct fuse_conn *fc = get_fuse_conn(inode);
struct fuse_file *ff = file->private_data;
FUSE_ARGS(args);
struct fuse_fsync_in inarg;
memset(&inarg, 0, sizeof(inarg));
inarg.fh = ff->fh;
inarg.fsync_flags = datasync ? FUSE_FSYNC_FDATASYNC : 0;
args.opcode = opcode;
args.nodeid = get_node_id(inode);
args.in_numargs = 1;
args.in_args[0].size = sizeof(inarg);
args.in_args[0].value = &inarg;
return fuse_simple_request(fc, &args);
}
static int fuse_fsync(struct file *file, loff_t start, loff_t end,
int datasync)
{
struct inode *inode = file->f_mapping->host;
struct fuse_conn *fc = get_fuse_conn(inode);
int err;
if (is_bad_inode(inode))
return -EIO;
inode_lock(inode);
/*
* Start writeback against all dirty pages of the inode, then
* wait for all outstanding writes, before sending the FSYNC
* request.
*/
err = file_write_and_wait_range(file, start, end);
if (err)
goto out;
fuse_sync_writes(inode);
/*
* Due to implementation of fuse writeback
* file_write_and_wait_range() does not catch errors.
* We have to do this directly after fuse_sync_writes()
*/
err = file_check_and_advance_wb_err(file);
if (err)
goto out;
err = sync_inode_metadata(inode, 1);
if (err)
goto out;
if (fc->no_fsync)
goto out;
err = fuse_fsync_common(file, start, end, datasync, FUSE_FSYNC);
if (err == -ENOSYS) {
fc->no_fsync = 1;
err = 0;
}
out:
inode_unlock(inode);
return err;
}
void fuse_read_args_fill(struct fuse_io_args *ia, struct file *file, loff_t pos,
size_t count, int opcode)
{
struct fuse_file *ff = file->private_data;
struct fuse_args *args = &ia->ap.args;
ia->read.in.fh = ff->fh;
ia->read.in.offset = pos;
ia->read.in.size = count;
ia->read.in.flags = file->f_flags;
args->opcode = opcode;
args->nodeid = ff->nodeid;
args->in_numargs = 1;
args->in_args[0].size = sizeof(ia->read.in);
args->in_args[0].value = &ia->read.in;
args->out_argvar = true;
args->out_numargs = 1;
args->out_args[0].size = count;
}
static void fuse_release_user_pages(struct fuse_args_pages *ap,
bool should_dirty)
{
unsigned int i;
for (i = 0; i < ap->num_pages; i++) {
if (should_dirty)
set_page_dirty_lock(ap->pages[i]);
put_page(ap->pages[i]);
}
}
static void fuse_io_release(struct kref *kref)
{
kfree(container_of(kref, struct fuse_io_priv, refcnt));
}
static ssize_t fuse_get_res_by_io(struct fuse_io_priv *io)
{
if (io->err)
return io->err;
if (io->bytes >= 0 && io->write)
return -EIO;
return io->bytes < 0 ? io->size : io->bytes;
}
/**
* In case of short read, the caller sets 'pos' to the position of
* actual end of fuse request in IO request. Otherwise, if bytes_requested
* == bytes_transferred or rw == WRITE, the caller sets 'pos' to -1.
*
* An example:
* User requested DIO read of 64K. It was splitted into two 32K fuse requests,
* both submitted asynchronously. The first of them was ACKed by userspace as
* fully completed (req->out.args[0].size == 32K) resulting in pos == -1. The
* second request was ACKed as short, e.g. only 1K was read, resulting in
* pos == 33K.
*
* Thus, when all fuse requests are completed, the minimal non-negative 'pos'
* will be equal to the length of the longest contiguous fragment of
* transferred data starting from the beginning of IO request.
*/
static void fuse_aio_complete(struct fuse_io_priv *io, int err, ssize_t pos)
{
int left;
spin_lock(&io->lock);
if (err)
io->err = io->err ? : err;
else if (pos >= 0 && (io->bytes < 0 || pos < io->bytes))
io->bytes = pos;
left = --io->reqs;
if (!left && io->blocking)
complete(io->done);
spin_unlock(&io->lock);
if (!left && !io->blocking) {
ssize_t res = fuse_get_res_by_io(io);
if (res >= 0) {
struct inode *inode = file_inode(io->iocb->ki_filp);
struct fuse_conn *fc = get_fuse_conn(inode);
struct fuse_inode *fi = get_fuse_inode(inode);
spin_lock(&fi->lock);
fi->attr_version = atomic64_inc_return(&fc->attr_version);
spin_unlock(&fi->lock);
}
io->iocb->ki_complete(io->iocb, res, 0);
}
kref_put(&io->refcnt, fuse_io_release);
}
static struct fuse_io_args *fuse_io_alloc(struct fuse_io_priv *io,
unsigned int npages)
{
struct fuse_io_args *ia;
ia = kzalloc(sizeof(*ia), GFP_KERNEL);
if (ia) {
ia->io = io;
ia->ap.pages = fuse_pages_alloc(npages, GFP_KERNEL,
&ia->ap.descs);
if (!ia->ap.pages) {
kfree(ia);
ia = NULL;
}
}
return ia;
}
static void fuse_io_free(struct fuse_io_args *ia)
{
kfree(ia->ap.pages);
kfree(ia);
}
static void fuse_aio_complete_req(struct fuse_conn *fc, struct fuse_args *args,
int err)
{
struct fuse_io_args *ia = container_of(args, typeof(*ia), ap.args);
struct fuse_io_priv *io = ia->io;
ssize_t pos = -1;
fuse_release_user_pages(&ia->ap, io->should_dirty);
if (err) {
/* Nothing */
} else if (io->write) {
if (ia->write.out.size > ia->write.in.size) {
err = -EIO;
} else if (ia->write.in.size != ia->write.out.size) {
pos = ia->write.in.offset - io->offset +
ia->write.out.size;
}
} else {
u32 outsize = args->out_args[0].size;
if (ia->read.in.size != outsize)
pos = ia->read.in.offset - io->offset + outsize;
}
fuse_aio_complete(io, err, pos);
fuse_io_free(ia);
}
static ssize_t fuse_async_req_send(struct fuse_conn *fc,
struct fuse_io_args *ia, size_t num_bytes)
{
ssize_t err;
struct fuse_io_priv *io = ia->io;
spin_lock(&io->lock);
kref_get(&io->refcnt);
io->size += num_bytes;
io->reqs++;
spin_unlock(&io->lock);
ia->ap.args.end = fuse_aio_complete_req;
err = fuse_simple_background(fc, &ia->ap.args, GFP_KERNEL);
if (err)
fuse_aio_complete_req(fc, &ia->ap.args, err);
return num_bytes;
}
static ssize_t fuse_send_read(struct fuse_io_args *ia, loff_t pos, size_t count,
fl_owner_t owner)
{
struct file *file = ia->io->iocb->ki_filp;
struct fuse_file *ff = file->private_data;
struct fuse_conn *fc = ff->fc;
fuse_read_args_fill(ia, file, pos, count, FUSE_READ);
if (owner != NULL) {
ia->read.in.read_flags |= FUSE_READ_LOCKOWNER;
ia->read.in.lock_owner = fuse_lock_owner_id(fc, owner);
}
if (ia->io->async)
return fuse_async_req_send(fc, ia, count);
return fuse_simple_request(fc, &ia->ap.args);
}
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(&fi->lock);
if (attr_ver == fi->attr_version && size < inode->i_size &&
!test_bit(FUSE_I_SIZE_UNSTABLE, &fi->state)) {
fi->attr_version = atomic64_inc_return(&fc->attr_version);
i_size_write(inode, size);
}
spin_unlock(&fi->lock);
}
static void fuse_short_read(struct inode *inode, u64 attr_ver, size_t num_read,
struct fuse_args_pages *ap)
{
struct fuse_conn *fc = get_fuse_conn(inode);
if (fc->writeback_cache) {
/*
* A hole in a file. Some data after the hole are in page cache,
* but have not reached the client fs yet. So, the hole is not
* present there.
*/
int i;
int start_idx = num_read >> PAGE_SHIFT;
size_t off = num_read & (PAGE_SIZE - 1);
for (i = start_idx; i < ap->num_pages; i++) {
zero_user_segment(ap->pages[i], off, PAGE_SIZE);
off = 0;
}
} else {
loff_t pos = page_offset(ap->pages[0]) + num_read;
fuse_read_update_size(inode, pos, attr_ver);
}
}
static int fuse_do_readpage(struct file *file, struct page *page)
{
struct inode *inode = page->mapping->host;
struct fuse_conn *fc = get_fuse_conn(inode);
loff_t pos = page_offset(page);
struct fuse_page_desc desc = { .length = PAGE_SIZE };
struct fuse_io_args ia = {
.ap.args.page_zeroing = true,
.ap.args.out_pages = true,
.ap.num_pages = 1,
.ap.pages = &page,
.ap.descs = &desc,
};
ssize_t res;
u64 attr_ver;
/*
* 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);
attr_ver = fuse_get_attr_version(fc);
/* Don't overflow end offset */
if (pos + (desc.length - 1) == LLONG_MAX)
desc.length--;
fuse_read_args_fill(&ia, file, pos, desc.length, FUSE_READ);
res = fuse_simple_request(fc, &ia.ap.args);
if (res < 0)
return res;
/*
* Short read means EOF. If file size is larger, truncate it
*/
if (res < desc.length)
fuse_short_read(inode, attr_ver, res, &ia.ap);
SetPageUptodate(page);
return 0;
}
static int fuse_readpage(struct file *file, struct page *page)
{
struct inode *inode = page->mapping->host;
int err;
err = -EIO;
if (is_bad_inode(inode))
goto out;
err = fuse_do_readpage(file, page);
fuse_invalidate_atime(inode);
out:
unlock_page(page);
return err;
}
static void fuse_readpages_end(struct fuse_conn *fc, struct fuse_args *args,
int err)
{
int i;
struct fuse_io_args *ia = container_of(args, typeof(*ia), ap.args);
struct fuse_args_pages *ap = &ia->ap;
size_t count = ia->read.in.size;
size_t num_read = args->out_args[0].size;
struct address_space *mapping = NULL;
for (i = 0; mapping == NULL && i < ap->num_pages; i++)
mapping = ap->pages[i]->mapping;
if (mapping) {
struct inode *inode = mapping->host;
/*
* Short read means EOF. If file size is larger, truncate it
*/
if (!err && num_read < count)
fuse_short_read(inode, ia->read.attr_ver, num_read, ap);
fuse_invalidate_atime(inode);
}
for (i = 0; i < ap->num_pages; i++) {
struct page *page = ap->pages[i];
if (!err)
SetPageUptodate(page);
else
SetPageError(page);
unlock_page(page);
put_page(page);
}
if (ia->ff)
fuse_file_put(ia->ff, false, false);
fuse_io_free(ia);
}
static void fuse_send_readpages(struct fuse_io_args *ia, struct file *file)
{
struct fuse_file *ff = file->private_data;
struct fuse_conn *fc = ff->fc;
struct fuse_args_pages *ap = &ia->ap;
loff_t pos = page_offset(ap->pages[0]);
size_t count = ap->num_pages << PAGE_SHIFT;
ssize_t res;
int err;
ap->args.out_pages = true;
ap->args.page_zeroing = true;
ap->args.page_replace = true;
/* Don't overflow end offset */
if (pos + (count - 1) == LLONG_MAX) {
count--;
ap->descs[ap->num_pages - 1].length--;
}
WARN_ON((loff_t) (pos + count) < 0);
fuse_read_args_fill(ia, file, pos, count, FUSE_READ);
ia->read.attr_ver = fuse_get_attr_version(fc);
if (fc->async_read) {
ia->ff = fuse_file_get(ff);
ap->args.end = fuse_readpages_end;
err = fuse_simple_background(fc, &ap->args, GFP_KERNEL);
if (!err)
return;
} else {
res = fuse_simple_request(fc, &ap->args);
err = res < 0 ? res : 0;
}
fuse_readpages_end(fc, &ap->args, err);
}
struct fuse_fill_data {
struct fuse_io_args *ia;
struct file *file;
struct inode *inode;
unsigned int nr_pages;
unsigned int max_pages;
};
static int fuse_readpages_fill(void *_data, struct page *page)
{
struct fuse_fill_data *data = _data;
struct fuse_io_args *ia = data->ia;
struct fuse_args_pages *ap = &ia->ap;
struct inode *inode = data->inode;
struct fuse_conn *fc = get_fuse_conn(inode);
fuse_wait_on_page_writeback(inode, page->index);
if (ap->num_pages &&
(ap->num_pages == fc->max_pages ||
(ap->num_pages + 1) * PAGE_SIZE > fc->max_read ||
ap->pages[ap->num_pages - 1]->index + 1 != page->index)) {
data->max_pages = min_t(unsigned int, data->nr_pages,
fc->max_pages);
fuse_send_readpages(ia, data->file);
data->ia = ia = fuse_io_alloc(NULL, data->max_pages);
if (!ia) {
unlock_page(page);
return -ENOMEM;
}
ap = &ia->ap;
}
if (WARN_ON(ap->num_pages >= data->max_pages)) {
unlock_page(page);
fuse_io_free(ia);
return -EIO;
}
get_page(page);
ap->pages[ap->num_pages] = page;
ap->descs[ap->num_pages].length = PAGE_SIZE;
ap->num_pages++;
data->nr_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.nr_pages = nr_pages;
data.max_pages = min_t(unsigned int, nr_pages, fc->max_pages);
;
data.ia = fuse_io_alloc(NULL, data.max_pages);
err = -ENOMEM;
if (!data.ia)
goto out;
err = read_cache_pages(mapping, pages, fuse_readpages_fill, &data);
if (!err) {
if (data.ia->ap.num_pages)
fuse_send_readpages(data.ia, file);
else
fuse_io_free(data.ia);
}
out:
return err;
}
static ssize_t fuse_cache_read_iter(struct kiocb *iocb, struct iov_iter *to)
{
struct inode *inode = iocb->ki_filp->f_mapping->host;
struct fuse_conn *fc = get_fuse_conn(inode);
/*
* In auto invalidate mode, always update attributes on read.
* Otherwise, only update if we attempt to read past EOF (to ensure
* i_size is up to date).
*/
if (fc->auto_inval_data ||
(iocb->ki_pos + iov_iter_count(to) > i_size_read(inode))) {
int err;
err = fuse_update_attributes(inode, iocb->ki_filp);
if (err)
return err;
}
return generic_file_read_iter(iocb, to);
}
static void fuse_write_args_fill(struct fuse_io_args *ia, struct fuse_file *ff,
loff_t pos, size_t count)
{
struct fuse_args *args = &ia->ap.args;
ia->write.in.fh = ff->fh;
ia->write.in.offset = pos;
ia->write.in.size = count;
args->opcode = FUSE_WRITE;
args->nodeid = ff->nodeid;
args->in_numargs = 2;
if (ff->fc->minor < 9)
args->in_args[0].size = FUSE_COMPAT_WRITE_IN_SIZE;
else
args->in_args[0].size = sizeof(ia->write.in);
args->in_args[0].value = &ia->write.in;
args->in_args[1].size = count;
args->out_numargs = 1;
args->out_args[0].size = sizeof(ia->write.out);
args->out_args[0].value = &ia->write.out;
}
static unsigned int fuse_write_flags(struct kiocb *iocb)
{
unsigned int flags = iocb->ki_filp->f_flags;
if (iocb->ki_flags & IOCB_DSYNC)
flags |= O_DSYNC;
if (iocb->ki_flags & IOCB_SYNC)
flags |= O_SYNC;
return flags;
}
static ssize_t fuse_send_write(struct fuse_io_args *ia, loff_t pos,
size_t count, fl_owner_t owner)
{
struct kiocb *iocb = ia->io->iocb;
struct file *file = iocb->ki_filp;
struct fuse_file *ff = file->private_data;
struct fuse_conn *fc = ff->fc;
struct fuse_write_in *inarg = &ia->write.in;
ssize_t err;
fuse_write_args_fill(ia, ff, pos, count);
inarg->flags = fuse_write_flags(iocb);
if (owner != NULL) {
inarg->write_flags |= FUSE_WRITE_LOCKOWNER;
inarg->lock_owner = fuse_lock_owner_id(fc, owner);
}
if (ia->io->async)
return fuse_async_req_send(fc, ia, count);
err = fuse_simple_request(fc, &ia->ap.args);
if (!err && ia->write.out.size > count)
err = -EIO;
return err ?: ia->write.out.size;
}
bool 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);
bool ret = false;
spin_lock(&fi->lock);
fi->attr_version = atomic64_inc_return(&fc->attr_version);
if (pos > inode->i_size) {
i_size_write(inode, pos);
ret = true;
}
spin_unlock(&fi->lock);
return ret;
}
static ssize_t fuse_send_write_pages(struct fuse_io_args *ia,
struct kiocb *iocb, struct inode *inode,
loff_t pos, size_t count)
{
struct fuse_args_pages *ap = &ia->ap;
struct file *file = iocb->ki_filp;
struct fuse_file *ff = file->private_data;
struct fuse_conn *fc = ff->fc;
unsigned int offset, i;
int err;
for (i = 0; i < ap->num_pages; i++)
fuse_wait_on_page_writeback(inode, ap->pages[i]->index);
fuse_write_args_fill(ia, ff, pos, count);
ia->write.in.flags = fuse_write_flags(iocb);
err = fuse_simple_request(fc, &ap->args);
if (!err && ia->write.out.size > count)
err = -EIO;
offset = ap->descs[0].offset;
count = ia->write.out.size;
for (i = 0; i < ap->num_pages; i++) {
struct page *page = ap->pages[i];
if (!err && !offset && count >= PAGE_SIZE)
SetPageUptodate(page);
if (count > PAGE_SIZE - offset)
count -= PAGE_SIZE - offset;
else
count = 0;
offset = 0;
unlock_page(page);
put_page(page);
}
return err;
}
static ssize_t fuse_fill_write_pages(struct fuse_args_pages *ap,
struct address_space *mapping,
struct iov_iter *ii, loff_t pos,
unsigned int max_pages)
{
struct fuse_conn *fc = get_fuse_conn(mapping->host);
unsigned offset = pos & (PAGE_SIZE - 1);
size_t count = 0;
int err;
ap->args.in_pages = true;
ap->descs[0].offset = offset;
do {
size_t tmp;
struct page *page;
pgoff_t index = pos >> PAGE_SHIFT;
size_t bytes = min_t(size_t, PAGE_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);
tmp = iov_iter_copy_from_user_atomic(page, ii, offset, bytes);
flush_dcache_page(page);
iov_iter_advance(ii, tmp);
if (!tmp) {
unlock_page(page);
put_page(page);
bytes = min(bytes, iov_iter_single_seg_count(ii));
goto again;
}
err = 0;
ap->pages[ap->num_pages] = page;
ap->descs[ap->num_pages].length = tmp;
ap->num_pages++;
count += tmp;
pos += tmp;
offset += tmp;
if (offset == PAGE_SIZE)
offset = 0;
if (!fc->big_writes)
break;
} while (iov_iter_count(ii) && count < fc->max_write &&
ap->num_pages < max_pages && offset == 0);
return count > 0 ? count : err;
}
static inline unsigned int fuse_wr_pages(loff_t pos, size_t len,
unsigned int max_pages)
{
return min_t(unsigned int,
((pos + len - 1) >> PAGE_SHIFT) -
(pos >> PAGE_SHIFT) + 1,
max_pages);
}
static ssize_t fuse_perform_write(struct kiocb *iocb,
struct address_space *mapping,
struct iov_iter *ii, loff_t pos)
{
struct inode *inode = mapping->host;
struct fuse_conn *fc = get_fuse_conn(inode);
struct fuse_inode *fi = get_fuse_inode(inode);
int err = 0;
ssize_t res = 0;
if (inode->i_size < pos + iov_iter_count(ii))
set_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
do {
ssize_t count;
struct fuse_io_args ia = {};
struct fuse_args_pages *ap = &ia.ap;
unsigned int nr_pages = fuse_wr_pages(pos, iov_iter_count(ii),
fc->max_pages);
ap->pages = fuse_pages_alloc(nr_pages, GFP_KERNEL, &ap->descs);
if (!ap->pages) {
err = -ENOMEM;
break;
}
count = fuse_fill_write_pages(ap, mapping, ii, pos, nr_pages);
if (count <= 0) {
err = count;
} else {
err = fuse_send_write_pages(&ia, iocb, inode,
pos, count);
if (!err) {
size_t num_written = ia.write.out.size;
res += num_written;
pos += num_written;
/* break out of the loop on short write */
if (num_written != count)
err = -EIO;
}
}
kfree(ap->pages);
} while (!err && iov_iter_count(ii));
if (res > 0)
fuse_write_update_size(inode, pos);
clear_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
fuse_invalidate_attr(inode);
return res > 0 ? res : err;
}
static ssize_t fuse_cache_write_iter(struct kiocb *iocb, struct iov_iter *from)
{
struct file *file = iocb->ki_filp;
struct address_space *mapping = file->f_mapping;
ssize_t written = 0;
ssize_t written_buffered = 0;
struct inode *inode = mapping->host;
ssize_t err;
loff_t endbyte = 0;
if (get_fuse_conn(inode)->writeback_cache) {
/* Update size (EOF optimization) and mode (SUID clearing) */
err = fuse_update_attributes(mapping->host, file);
if (err)
return err;
return generic_file_write_iter(iocb, from);
}
inode_lock(inode);
/* We can write back this queue in page reclaim */
current->backing_dev_info = inode_to_bdi(inode);
err = generic_write_checks(iocb, from);
if (err <= 0)
goto out;
err = file_remove_privs(file);
if (err)
goto out;
err = file_update_time(file);
if (err)
goto out;
if (iocb->ki_flags & IOCB_DIRECT) {
loff_t pos = iocb->ki_pos;
written = generic_file_direct_write(iocb, from);
if (written < 0 || !iov_iter_count(from))
goto out;
pos += written;
written_buffered = fuse_perform_write(iocb, mapping, from, pos);
if (written_buffered < 0) {
err = written_buffered;
goto out;
}
endbyte = pos + written_buffered - 1;
err = filemap_write_and_wait_range(file->f_mapping, pos,
endbyte);
if (err)
goto out;
invalidate_mapping_pages(file->f_mapping,
pos >> PAGE_SHIFT,
endbyte >> PAGE_SHIFT);
written += written_buffered;
iocb->ki_pos = pos + written_buffered;
} else {
written = fuse_perform_write(iocb, mapping, from, iocb->ki_pos);
if (written >= 0)
iocb->ki_pos += written;
}
out:
current->backing_dev_info = NULL;
inode_unlock(inode);
if (written > 0)
written = generic_write_sync(iocb, written);
return written ? written : err;
}
static inline void fuse_page_descs_length_init(struct fuse_page_desc *descs,
unsigned int index,
unsigned int nr_pages)
{
int i;
for (i = index; i < index + nr_pages; i++)
descs[i].length = PAGE_SIZE - descs[i].offset;
}
static inline unsigned long fuse_get_user_addr(const struct iov_iter *ii)
{
return (unsigned long)ii->iov->iov_base + ii->iov_offset;
}
static inline size_t fuse_get_frag_size(const struct iov_iter *ii,
size_t max_size)
{
return min(iov_iter_single_seg_count(ii), max_size);
}
static int fuse_get_user_pages(struct fuse_args_pages *ap, struct iov_iter *ii,
size_t *nbytesp, int write,
unsigned int max_pages)
{
size_t nbytes = 0; /* # bytes already packed in req */
ssize_t ret = 0;
/* Special case for kernel I/O: can copy directly into the buffer */
if (iov_iter_is_kvec(ii)) {
unsigned long user_addr = fuse_get_user_addr(ii);
size_t frag_size = fuse_get_frag_size(ii, *nbytesp);
if (write)
ap->args.in_args[1].value = (void *) user_addr;
else
ap->args.out_args[0].value = (void *) user_addr;
iov_iter_advance(ii, frag_size);
*nbytesp = frag_size;
return 0;
}
while (nbytes < *nbytesp && ap->num_pages < max_pages) {
unsigned npages;
size_t start;
ret = iov_iter_get_pages(ii, &ap->pages[ap->num_pages],
*nbytesp - nbytes,
max_pages - ap->num_pages,
&start);
if (ret < 0)
break;
iov_iter_advance(ii, ret);
nbytes += ret;
ret += start;
npages = (ret + PAGE_SIZE - 1) / PAGE_SIZE;
ap->descs[ap->num_pages].offset = start;
fuse_page_descs_length_init(ap->descs, ap->num_pages, npages);
ap->num_pages += npages;
ap->descs[ap->num_pages - 1].length -=
(PAGE_SIZE - ret) & (PAGE_SIZE - 1);
}
if (write)
ap->args.in_pages = true;
else
ap->args.out_pages = true;
*nbytesp = nbytes;
return ret < 0 ? ret : 0;
}
ssize_t fuse_direct_io(struct fuse_io_priv *io, struct iov_iter *iter,
loff_t *ppos, int flags)
{
int write = flags & FUSE_DIO_WRITE;
int cuse = flags & FUSE_DIO_CUSE;
struct file *file = io->iocb->ki_filp;
struct inode *inode = file->f_mapping->host;
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;
size_t count = iov_iter_count(iter);
pgoff_t idx_from = pos >> PAGE_SHIFT;
pgoff_t idx_to = (pos + count - 1) >> PAGE_SHIFT;
ssize_t res = 0;
int err = 0;
struct fuse_io_args *ia;
unsigned int max_pages;
max_pages = iov_iter_npages(iter, fc->max_pages);
ia = fuse_io_alloc(io, max_pages);
if (!ia)
return -ENOMEM;
ia->io = io;
if (!cuse && fuse_range_is_writeback(inode, idx_from, idx_to)) {
if (!write)
inode_lock(inode);
fuse_sync_writes(inode);
if (!write)
inode_unlock(inode);
}
io->should_dirty = !write && iter_is_iovec(iter);
while (count) {
ssize_t nres;
fl_owner_t owner = current->files;
size_t nbytes = min(count, nmax);
err = fuse_get_user_pages(&ia->ap, iter, &nbytes, write,
max_pages);
if (err && !nbytes)
break;
if (write) {
if (!capable(CAP_FSETID))
ia->write.in.write_flags |= FUSE_WRITE_KILL_PRIV;
nres = fuse_send_write(ia, pos, nbytes, owner);
} else {
nres = fuse_send_read(ia, pos, nbytes, owner);
}
if (!io->async || nres < 0) {
fuse_release_user_pages(&ia->ap, io->should_dirty);
fuse_io_free(ia);
}
ia = NULL;
if (nres < 0) {
iov_iter_revert(iter, nbytes);
err = nres;
break;
}
WARN_ON(nres > nbytes);
count -= nres;
res += nres;
pos += nres;
if (nres != nbytes) {
iov_iter_revert(iter, nbytes - nres);
break;
}
if (count) {
max_pages = iov_iter_npages(iter, fc->max_pages);
ia = fuse_io_alloc(io, max_pages);
if (!ia)
break;
}
}
if (ia)
fuse_io_free(ia);
if (res > 0)
*ppos = pos;
return res > 0 ? res : err;
}
EXPORT_SYMBOL_GPL(fuse_direct_io);
static ssize_t __fuse_direct_read(struct fuse_io_priv *io,
struct iov_iter *iter,
loff_t *ppos)
{
ssize_t res;
struct inode *inode = file_inode(io->iocb->ki_filp);
res = fuse_direct_io(io, iter, ppos, 0);
fuse_invalidate_atime(inode);
return res;
}
static ssize_t fuse_direct_IO(struct kiocb *iocb, struct iov_iter *iter);
static ssize_t fuse_direct_read_iter(struct kiocb *iocb, struct iov_iter *to)
{
ssize_t res;
if (!is_sync_kiocb(iocb) && iocb->ki_flags & IOCB_DIRECT) {
res = fuse_direct_IO(iocb, to);
} else {
struct fuse_io_priv io = FUSE_IO_PRIV_SYNC(iocb);
res = __fuse_direct_read(&io, to, &iocb->ki_pos);
}
return res;
}
static ssize_t fuse_direct_write_iter(struct kiocb *iocb, struct iov_iter *from)
{
struct inode *inode = file_inode(iocb->ki_filp);
struct fuse_io_priv io = FUSE_IO_PRIV_SYNC(iocb);
ssize_t res;
/* Don't allow parallel writes to the same file */
inode_lock(inode);
res = generic_write_checks(iocb, from);
if (res > 0) {
if (!is_sync_kiocb(iocb) && iocb->ki_flags & IOCB_DIRECT) {
res = fuse_direct_IO(iocb, from);
} else {
res = fuse_direct_io(&io, from, &iocb->ki_pos,
FUSE_DIO_WRITE);
}
}
fuse_invalidate_attr(inode);
if (res > 0)
fuse_write_update_size(inode, iocb->ki_pos);
inode_unlock(inode);
return res;
}
static ssize_t fuse_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
{
struct file *file = iocb->ki_filp;
struct fuse_file *ff = file->private_data;
if (is_bad_inode(file_inode(file)))
return -EIO;
if (!(ff->open_flags & FOPEN_DIRECT_IO))
return fuse_cache_read_iter(iocb, to);
else
return fuse_direct_read_iter(iocb, to);
}
static ssize_t fuse_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
{
struct file *file = iocb->ki_filp;
struct fuse_file *ff = file->private_data;
if (is_bad_inode(file_inode(file)))
return -EIO;
if (!(ff->open_flags & FOPEN_DIRECT_IO))
return fuse_cache_write_iter(iocb, from);
else
return fuse_direct_write_iter(iocb, from);
}
static void fuse_writepage_free(struct fuse_writepage_args *wpa)
{
struct fuse_args_pages *ap = &wpa->ia.ap;
int i;
for (i = 0; i < ap->num_pages; i++)
__free_page(ap->pages[i]);
if (wpa->ia.ff)
fuse_file_put(wpa->ia.ff, false, false);
kfree(ap->pages);
kfree(wpa);
}
static void fuse_writepage_finish(struct fuse_conn *fc,
struct fuse_writepage_args *wpa)
{
struct fuse_args_pages *ap = &wpa->ia.ap;
struct inode *inode = wpa->inode;
struct fuse_inode *fi = get_fuse_inode(inode);
struct backing_dev_info *bdi = inode_to_bdi(inode);
int i;
list_del(&wpa->writepages_entry);
for (i = 0; i < ap->num_pages; i++) {
dec_wb_stat(&bdi->wb, WB_WRITEBACK);
dec_node_page_state(ap->pages[i], NR_WRITEBACK_TEMP);
wb_writeout_inc(&bdi->wb);
}
wake_up(&fi->page_waitq);
}
/* Called under fi->lock, may release and reacquire it */
static void fuse_send_writepage(struct fuse_conn *fc,
struct fuse_writepage_args *wpa, loff_t size)
__releases(fi->lock)
__acquires(fi->lock)
{
struct fuse_writepage_args *aux, *next;
struct fuse_inode *fi = get_fuse_inode(wpa->inode);
struct fuse_write_in *inarg = &wpa->ia.write.in;
struct fuse_args *args = &wpa->ia.ap.args;
__u64 data_size = wpa->ia.ap.num_pages * PAGE_SIZE;
int err;
fi->writectr++;
if (inarg->offset + data_size <= size) {
inarg->size = data_size;
} else if (inarg->offset < size) {
inarg->size = size - inarg->offset;
} else {
/* Got truncated off completely */
goto out_free;
}
args->in_args[1].size = inarg->size;
args->force = true;
args->nocreds = true;
err = fuse_simple_background(fc, args, GFP_ATOMIC);
if (err == -ENOMEM) {
spin_unlock(&fi->lock);
err = fuse_simple_background(fc, args, GFP_NOFS | __GFP_NOFAIL);
spin_lock(&fi->lock);
}
/* Fails on broken connection only */
if (unlikely(err))
goto out_free;
return;
out_free:
fi->writectr--;
fuse_writepage_finish(fc, wpa);
spin_unlock(&fi->lock);
/* After fuse_writepage_finish() aux request list is private */
for (aux = wpa->next; aux; aux = next) {
next = aux->next;
aux->next = NULL;
fuse_writepage_free(aux);
}
fuse_writepage_free(wpa);
spin_lock(&fi->lock);
}
/*
* If fi->writectr is positive (no truncate or fsync going on) send
* all queued writepage requests.
*
* Called with fi->lock
*/
void fuse_flush_writepages(struct inode *inode)
__releases(fi->lock)
__acquires(fi->lock)
{
struct fuse_conn *fc = get_fuse_conn(inode);
struct fuse_inode *fi = get_fuse_inode(inode);
loff_t crop = i_size_read(inode);
struct fuse_writepage_args *wpa;
while (fi->writectr >= 0 && !list_empty(&fi->queued_writes)) {
wpa = list_entry(fi->queued_writes.next,
struct fuse_writepage_args, queue_entry);
list_del_init(&wpa->queue_entry);
fuse_send_writepage(fc, wpa, crop);
}
}
static void fuse_writepage_end(struct fuse_conn *fc, struct fuse_args *args,
int error)
{
struct fuse_writepage_args *wpa =
container_of(args, typeof(*wpa), ia.ap.args);
struct inode *inode = wpa->inode;
struct fuse_inode *fi = get_fuse_inode(inode);
mapping_set_error(inode->i_mapping, error);
spin_lock(&fi->lock);
while (wpa->next) {
struct fuse_conn *fc = get_fuse_conn(inode);
struct fuse_write_in *inarg = &wpa->ia.write.in;
struct fuse_writepage_args *next = wpa->next;
wpa->next = next->next;
next->next = NULL;
next->ia.ff = fuse_file_get(wpa->ia.ff);
list_add(&next->writepages_entry, &fi->writepages);
/*
* Skip fuse_flush_writepages() to make it easy to crop requests
* based on primary request size.
*
* 1st case (trivial): there are no concurrent activities using
* fuse_set/release_nowrite. Then we're on safe side because
* fuse_flush_writepages() would call fuse_send_writepage()
* anyway.
*
* 2nd case: someone called fuse_set_nowrite and it is waiting
* now for completion of all in-flight requests. This happens
* rarely and no more than once per page, so this should be
* okay.
*
* 3rd case: someone (e.g. fuse_do_setattr()) is in the middle
* of fuse_set_nowrite..fuse_release_nowrite section. The fact
* that fuse_set_nowrite returned implies that all in-flight
* requests were completed along with all of their secondary
* requests. Further primary requests are blocked by negative
* writectr. Hence there cannot be any in-flight requests and
* no invocations of fuse_writepage_end() while we're in
* fuse_set_nowrite..fuse_release_nowrite section.
*/
fuse_send_writepage(fc, next, inarg->offset + inarg->size);
}
fi->writectr--;
fuse_writepage_finish(fc, wpa);
spin_unlock(&fi->lock);
fuse_writepage_free(wpa);
}
static struct fuse_file *__fuse_write_file_get(struct fuse_conn *fc,
struct fuse_inode *fi)
{
struct fuse_file *ff = NULL;
spin_lock(&fi->lock);
if (!list_empty(&fi->write_files)) {
ff = list_entry(fi->write_files.next, struct fuse_file,
write_entry);
fuse_file_get(ff);
}
spin_unlock(&fi->lock);
return ff;
}
static struct fuse_file *fuse_write_file_get(struct fuse_conn *fc,
struct fuse_inode *fi)
{
struct fuse_file *ff = __fuse_write_file_get(fc, fi);
WARN_ON(!ff);
return ff;
}
int fuse_write_inode(struct inode *inode, struct writeback_control *wbc)
{
struct fuse_conn *fc = get_fuse_conn(inode);
struct fuse_inode *fi = get_fuse_inode(inode);
struct fuse_file *ff;
int err;
ff = __fuse_write_file_get(fc, fi);
err = fuse_flush_times(inode, ff);
if (ff)
fuse_file_put(ff, false, false);
return err;
}
static struct fuse_writepage_args *fuse_writepage_args_alloc(void)
{
struct fuse_writepage_args *wpa;
struct fuse_args_pages *ap;
wpa = kzalloc(sizeof(*wpa), GFP_NOFS);
if (wpa) {
ap = &wpa->ia.ap;
ap->num_pages = 0;
ap->pages = fuse_pages_alloc(1, GFP_NOFS, &ap->descs);
if (!ap->pages) {
kfree(wpa);
wpa = NULL;
}
}
return wpa;
}
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_writepage_args *wpa;
struct fuse_args_pages *ap;
struct page *tmp_page;
int error = -ENOMEM;
set_page_writeback(page);
wpa = fuse_writepage_args_alloc();
if (!wpa)
goto err;
ap = &wpa->ia.ap;
tmp_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
if (!tmp_page)
goto err_free;
error = -EIO;
wpa->ia.ff = fuse_write_file_get(fc, fi);
if (!wpa->ia.ff)
goto err_nofile;
fuse_write_args_fill(&wpa->ia, wpa->ia.ff, page_offset(page), 0);
copy_highpage(tmp_page, page);
wpa->ia.write.in.write_flags |= FUSE_WRITE_CACHE;
wpa->next = NULL;
ap->args.in_pages = true;
ap->num_pages = 1;
ap->pages[0] = tmp_page;
ap->descs[0].offset = 0;
ap->descs[0].length = PAGE_SIZE;
ap->args.end = fuse_writepage_end;
wpa->inode = inode;
inc_wb_stat(&inode_to_bdi(inode)->wb, WB_WRITEBACK);
inc_node_page_state(tmp_page, NR_WRITEBACK_TEMP);
spin_lock(&fi->lock);
list_add(&wpa->writepages_entry, &fi->writepages);
list_add_tail(&wpa->queue_entry, &fi->queued_writes);
fuse_flush_writepages(inode);
spin_unlock(&fi->lock);
end_page_writeback(page);
return 0;
err_nofile:
__free_page(tmp_page);
err_free:
kfree(wpa);
err:
mapping_set_error(page->mapping, error);
end_page_writeback(page);
return error;
}
static int fuse_writepage(struct page *page, struct writeback_control *wbc)
{
int err;
if (fuse_page_is_writeback(page->mapping->host, page->index)) {
/*
* ->writepages() should be called for sync() and friends. We
* should only get here on direct reclaim and then we are
* allowed to skip a page which is already in flight
*/
WARN_ON(wbc->sync_mode == WB_SYNC_ALL);
redirty_page_for_writepage(wbc, page);
unlock_page(page);
return 0;
}
err = fuse_writepage_locked(page);
unlock_page(page);
return err;
}
struct fuse_fill_wb_data {
struct fuse_writepage_args *wpa;
struct fuse_file *ff;
struct inode *inode;
struct page **orig_pages;
unsigned int max_pages;
};
static bool fuse_pages_realloc(struct fuse_fill_wb_data *data)
{
struct fuse_args_pages *ap = &data->wpa->ia.ap;
struct fuse_conn *fc = get_fuse_conn(data->inode);
struct page **pages;
struct fuse_page_desc *descs;
unsigned int npages = min_t(unsigned int,
max_t(unsigned int, data->max_pages * 2,
FUSE_DEFAULT_MAX_PAGES_PER_REQ),
fc->max_pages);
WARN_ON(npages <= data->max_pages);
pages = fuse_pages_alloc(npages, GFP_NOFS, &descs);
if (!pages)
return false;
memcpy(pages, ap->pages, sizeof(struct page *) * ap->num_pages);
memcpy(descs, ap->descs, sizeof(struct fuse_page_desc) * ap->num_pages);
kfree(ap->pages);
ap->pages = pages;
ap->descs = descs;
data->max_pages = npages;
return true;
}
static void fuse_writepages_send(struct fuse_fill_wb_data *data)
{
struct fuse_writepage_args *wpa = data->wpa;
struct inode *inode = data->inode;
struct fuse_inode *fi = get_fuse_inode(inode);
int num_pages = wpa->ia.ap.num_pages;
int i;
wpa->ia.ff = fuse_file_get(data->ff);
spin_lock(&fi->lock);
list_add_tail(&wpa->queue_entry, &fi->queued_writes);
fuse_flush_writepages(inode);
spin_unlock(&fi->lock);
for (i = 0; i < num_pages; i++)
end_page_writeback(data->orig_pages[i]);
}
/*
* First recheck under fi->lock if the offending offset is still under
* writeback. If yes, then iterate auxiliary write requests, to see if there's
* one already added for a page at this offset. If there's none, then insert
* this new request onto the auxiliary list, otherwise reuse the existing one by
* copying the new page contents over to the old temporary page.
*/
static bool fuse_writepage_in_flight(struct fuse_writepage_args *new_wpa,
struct page *page)
{
struct fuse_inode *fi = get_fuse_inode(new_wpa->inode);
struct fuse_writepage_args *tmp;
struct fuse_writepage_args *old_wpa;
struct fuse_args_pages *new_ap = &new_wpa->ia.ap;
WARN_ON(new_ap->num_pages != 0);
spin_lock(&fi->lock);
list_del(&new_wpa->writepages_entry);
old_wpa = fuse_find_writeback(fi, page->index, page->index);
if (!old_wpa) {
list_add(&new_wpa->writepages_entry, &fi->writepages);
spin_unlock(&fi->lock);
return false;
}
new_ap->num_pages = 1;
for (tmp = old_wpa->next; tmp; tmp = tmp->next) {
pgoff_t curr_index;
WARN_ON(tmp->inode != new_wpa->inode);
curr_index = tmp->ia.write.in.offset >> PAGE_SHIFT;
if (curr_index == page->index) {
WARN_ON(tmp->ia.ap.num_pages != 1);
swap(tmp->ia.ap.pages[0], new_ap->pages[0]);
break;
}
}
if (!tmp) {
new_wpa->next = old_wpa->next;
old_wpa->next = new_wpa;
}
spin_unlock(&fi->lock);
if (tmp) {
struct backing_dev_info *bdi = inode_to_bdi(new_wpa->inode);
dec_wb_stat(&bdi->wb, WB_WRITEBACK);
dec_node_page_state(new_ap->pages[0], NR_WRITEBACK_TEMP);
wb_writeout_inc(&bdi->wb);
fuse_writepage_free(new_wpa);
}
return true;
}
static int fuse_writepages_fill(struct page *page,
struct writeback_control *wbc, void *_data)
{
struct fuse_fill_wb_data *data = _data;
struct fuse_writepage_args *wpa = data->wpa;
struct fuse_args_pages *ap = &wpa->ia.ap;
struct inode *inode = data->inode;
struct fuse_inode *fi = get_fuse_inode(inode);
struct fuse_conn *fc = get_fuse_conn(inode);
struct page *tmp_page;
bool is_writeback;
int err;
if (!data->ff) {
err = -EIO;
data->ff = fuse_write_file_get(fc, fi);
if (!data->ff)
goto out_unlock;
}
/*
* Being under writeback is unlikely but possible. For example direct
* read to an mmaped fuse file will set the page dirty twice; once when
* the pages are faulted with get_user_pages(), and then after the read
* completed.
*/
is_writeback = fuse_page_is_writeback(inode, page->index);
if (wpa && ap->num_pages &&
(is_writeback || ap->num_pages == fc->max_pages ||
(ap->num_pages + 1) * PAGE_SIZE > fc->max_write ||
data->orig_pages[ap->num_pages - 1]->index + 1 != page->index)) {
fuse_writepages_send(data);
data->wpa = NULL;
} else if (wpa && ap->num_pages == data->max_pages) {
if (!fuse_pages_realloc(data)) {
fuse_writepages_send(data);
data->wpa = NULL;
}
}
err = -ENOMEM;
tmp_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
if (!tmp_page)
goto out_unlock;
/*
* The page must not be redirtied until the writeout is completed
* (i.e. userspace has sent a reply to the write request). Otherwise
* there could be more than one temporary page instance for each real
* page.
*
* This is ensured by holding the page lock in page_mkwrite() while
* checking fuse_page_is_writeback(). We already hold the page lock
* since clear_page_dirty_for_io() and keep it held until we add the
* request to the fi->writepages list and increment ap->num_pages.
* After this fuse_page_is_writeback() will indicate that the page is
* under writeback, so we can release the page lock.
*/
if (data->wpa == NULL) {
err = -ENOMEM;
wpa = fuse_writepage_args_alloc();
if (!wpa) {
__free_page(tmp_page);
goto out_unlock;
}
data->max_pages = 1;
ap = &wpa->ia.ap;
fuse_write_args_fill(&wpa->ia, data->ff, page_offset(page), 0);
wpa->ia.write.in.write_flags |= FUSE_WRITE_CACHE;
wpa->next = NULL;
ap->args.in_pages = true;
ap->args.end = fuse_writepage_end;
ap->num_pages = 0;
wpa->inode = inode;
spin_lock(&fi->lock);
list_add(&wpa->writepages_entry, &fi->writepages);
spin_unlock(&fi->lock);
data->wpa = wpa;
}
set_page_writeback(page);
copy_highpage(tmp_page, page);
ap->pages[ap->num_pages] = tmp_page;
ap->descs[ap->num_pages].offset = 0;
ap->descs[ap->num_pages].length = PAGE_SIZE;
inc_wb_stat(&inode_to_bdi(inode)->wb, WB_WRITEBACK);
inc_node_page_state(tmp_page, NR_WRITEBACK_TEMP);
err = 0;
if (is_writeback && fuse_writepage_in_flight(wpa, page)) {
end_page_writeback(page);
data->wpa = NULL;
goto out_unlock;
}
data->orig_pages[ap->num_pages] = page;
/*
* Protected by fi->lock against concurrent access by
* fuse_page_is_writeback().
*/
spin_lock(&fi->lock);
ap->num_pages++;
spin_unlock(&fi->lock);
out_unlock:
unlock_page(page);
return err;
}
static int fuse_writepages(struct address_space *mapping,
struct writeback_control *wbc)
{
struct inode *inode = mapping->host;
struct fuse_conn *fc = get_fuse_conn(inode);
struct fuse_fill_wb_data data;
int err;
err = -EIO;
if (is_bad_inode(inode))
goto out;
data.inode = inode;
data.wpa = NULL;
data.ff = NULL;
err = -ENOMEM;
data.orig_pages = kcalloc(fc->max_pages,
sizeof(struct page *),
GFP_NOFS);
if (!data.orig_pages)
goto out;
err = write_cache_pages(mapping, wbc, fuse_writepages_fill, &data);
if (data.wpa) {
/* Ignore errors if we can write at least one page */
WARN_ON(!data.wpa->ia.ap.num_pages);
fuse_writepages_send(&data);
err = 0;
}
if (data.ff)
fuse_file_put(data.ff, false, false);
kfree(data.orig_pages);
out:
return err;
}
/*
* It's worthy to make sure that space is reserved on disk for the write,
* but how to implement it without killing performance need more thinking.
*/
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_SHIFT;
struct fuse_conn *fc = get_fuse_conn(file_inode(file));
struct page *page;
loff_t fsize;
int err = -ENOMEM;
WARN_ON(!fc->writeback_cache);
page = grab_cache_page_write_begin(mapping, index, flags);
if (!page)
goto error;
fuse_wait_on_page_writeback(mapping->host, page->index);
if (PageUptodate(page) || len == PAGE_SIZE)
goto success;
/*
* Check if the start this page comes after the end of file, in which
* case the readpage can be optimized away.
*/
fsize = i_size_read(mapping->host);
if (fsize <= (pos & PAGE_MASK)) {
size_t off = pos & ~PAGE_MASK;
if (off)
zero_user_segment(page, 0, off);
goto success;
}
err = fuse_do_readpage(file, page);
if (err)
goto cleanup;
success:
*pagep = page;
return 0;
cleanup:
unlock_page(page);
put_page(page);
error:
return err;
}
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 = page->mapping->host;
/* Haven't copied anything? Skip zeroing, size extending, dirtying. */
if (!copied)
goto unlock;
if (!PageUptodate(page)) {
/* Zero any unwritten bytes at the end of the page */
size_t endoff = (pos + copied) & ~PAGE_MASK;
if (endoff)
zero_user_segment(page, endoff, PAGE_SIZE);
SetPageUptodate(page);
}
fuse_write_update_size(inode, pos + copied);
set_page_dirty(page);
unlock:
unlock_page(page);
put_page(page);
return copied;
}
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 vm_fault_t fuse_page_mkwrite(struct vm_fault *vmf)
{
struct page *page = vmf->page;
struct inode *inode = file_inode(vmf->vma->vm_file);
file_update_time(vmf->vma->vm_file);
lock_page(page);
if (page->mapping != inode->i_mapping) {
unlock_page(page);
return VM_FAULT_NOPAGE;
}
fuse_wait_on_page_writeback(inode, page->index);
return VM_FAULT_LOCKED;
}
static const struct vm_operations_struct fuse_file_vm_ops = {
.close = fuse_vma_close,
.fault = filemap_fault,
.map_pages = filemap_map_pages,
.page_mkwrite = fuse_page_mkwrite,
};
static int fuse_file_mmap(struct file *file, struct vm_area_struct *vma)
{
struct fuse_file *ff = file->private_data;
if (ff->open_flags & FOPEN_DIRECT_IO) {
/* 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);
}
if ((vma->vm_flags & VM_SHARED) && (vma->vm_flags & VM_MAYWRITE))
fuse_link_write_file(file);
file_accessed(file);
vma->vm_ops = &fuse_file_vm_ops;
return 0;
}
static int convert_fuse_file_lock(struct fuse_conn *fc,
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;
/*
* Convert pid into init's pid namespace. The locks API will
* translate it into the caller's pid namespace.
*/
rcu_read_lock();
fl->fl_pid = pid_nr_ns(find_pid_ns(ffl->pid, fc->pid_ns), &init_pid_ns);
rcu_read_unlock();
break;
default:
return -EIO;
}
fl->fl_type = ffl->type;
return 0;
}
static void fuse_lk_fill(struct fuse_args *args, struct file *file,
const struct file_lock *fl, int opcode, pid_t pid,
int flock, struct fuse_lk_in *inarg)
{
struct inode *inode = file_inode(file);
struct fuse_conn *fc = get_fuse_conn(inode);
struct fuse_file *ff = file->private_data;
memset(inarg, 0, sizeof(*inarg));
inarg->fh = ff->fh;
inarg->owner = fuse_lock_owner_id(fc, fl->fl_owner);
inarg->lk.start = fl->fl_start;
inarg->lk.end = fl->fl_end;
inarg->lk.type = fl->fl_type;
inarg->lk.pid = pid;
if (flock)
inarg->lk_flags |= FUSE_LK_FLOCK;
args->opcode = opcode;
args->nodeid = get_node_id(inode);
args->in_numargs = 1;
args->in_args[0].size = sizeof(*inarg);
args->in_args[0].value = inarg;
}
static int fuse_getlk(struct file *file, struct file_lock *fl)
{
struct inode *inode = file_inode(file);
struct fuse_conn *fc = get_fuse_conn(inode);
FUSE_ARGS(args);
struct fuse_lk_in inarg;
struct fuse_lk_out outarg;
int err;
fuse_lk_fill(&args, file, fl, FUSE_GETLK, 0, 0, &inarg);
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)
err = convert_fuse_file_lock(fc, &outarg.lk, fl);
return err;
}
static int fuse_setlk(struct file *file, struct file_lock *fl, int flock)
{
struct inode *inode = file_inode(file);
struct fuse_conn *fc = get_fuse_conn(inode);
FUSE_ARGS(args);
struct fuse_lk_in inarg;
int opcode = (fl->fl_flags & FL_SLEEP) ? FUSE_SETLKW : FUSE_SETLK;
struct pid *pid = fl->fl_type != F_UNLCK ? task_tgid(current) : NULL;
pid_t pid_nr = pid_nr_ns(pid, fc->pid_ns);
int err;
if (fl->fl_lmops && fl->fl_lmops->lm_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_POSIX) == FL_CLOSE_POSIX)
return 0;
fuse_lk_fill(&args, file, fl, opcode, pid_nr, flock, &inarg);
err = fuse_simple_request(fc, &args);
/* locking is restartable */
if (err == -EINTR)
err = -ERESTARTSYS;
return err;
}
static int fuse_file_lock(struct file *file, int cmd, struct file_lock *fl)
{
struct inode *inode = file_inode(file);
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_inode(file);
struct fuse_conn *fc = get_fuse_conn(inode);
int err;
if (fc->no_flock) {
err = locks_lock_file_wait(file, fl);
} else {
struct fuse_file *ff = file->private_data;
/* emulate flock with POSIX locks */
ff->flock = true;
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);
FUSE_ARGS(args);
struct fuse_bmap_in inarg;
struct fuse_bmap_out outarg;
int err;
if (!inode->i_sb->s_bdev || fc->no_bmap)
return 0;
memset(&inarg, 0, sizeof(inarg));
inarg.block = block;
inarg.blocksize = inode->i_sb->s_blocksize;
args.opcode = FUSE_BMAP;
args.nodeid = get_node_id(inode);
args.in_numargs = 1;
args.in_args[0].size = sizeof(inarg);
args.in_args[0].value = &inarg;
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 == -ENOSYS)
fc->no_bmap = 1;
return err ? 0 : outarg.block;
}
static loff_t fuse_lseek(struct file *file, loff_t offset, int whence)
{
struct inode *inode = file->f_mapping->host;
struct fuse_conn *fc = get_fuse_conn(inode);
struct fuse_file *ff = file->private_data;
FUSE_ARGS(args);
struct fuse_lseek_in inarg = {
.fh = ff->fh,
.offset = offset,
.whence = whence
};
struct fuse_lseek_out outarg;
int err;
if (fc->no_lseek)
goto fallback;
args.opcode = FUSE_LSEEK;
args.nodeid = ff->nodeid;
args.in_numargs = 1;
args.in_args[0].size = sizeof(inarg);
args.in_args[0].value = &inarg;
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) {
if (err == -ENOSYS) {
fc->no_lseek = 1;
goto fallback;
}
return err;
}
return vfs_setpos(file, outarg.offset, inode->i_sb->s_maxbytes);
fallback:
err = fuse_update_attributes(inode, file);
if (!err)
return generic_file_llseek(file, offset, whence);
else
return err;
}
static loff_t fuse_file_llseek(struct file *file, loff_t offset, int whence)
{
loff_t retval;
struct inode *inode = file_inode(file);
switch (whence) {
case SEEK_SET:
case SEEK_CUR:
/* No i_mutex protection necessary for SEEK_CUR and SEEK_SET */
retval = generic_file_llseek(file, offset, whence);
break;
case SEEK_END:
inode_lock(inode);
retval = fuse_update_attributes(inode, file);
if (!retval)
retval = generic_file_llseek(file, offset, whence);
inode_unlock(inode);
break;
case SEEK_HOLE:
case SEEK_DATA:
inode_lock(inode);
retval = fuse_lseek(file, offset, whence);
inode_unlock(inode);
break;
default:
retval = -EINVAL;
}
return retval;
}
/*
* 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 fuse_conn *fc, struct iovec *iov,
size_t count)
{
size_t n;
u32 max = fc->max_pages << 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 iovec *iov_page = NULL;
struct iovec *in_iov = NULL, *out_iov = NULL;
unsigned int in_iovs = 0, out_iovs = 0, max_pages;
size_t in_size, out_size, c;
ssize_t transferred;
int err, i;
struct iov_iter ii;
struct fuse_args_pages ap = {};
#if BITS_PER_LONG == 32
inarg.flags |= FUSE_IOCTL_32BIT;
#else
if (flags & FUSE_IOCTL_COMPAT) {
inarg.flags |= FUSE_IOCTL_32BIT;
#ifdef CONFIG_X86_X32
if (in_x32_syscall())
inarg.flags |= FUSE_IOCTL_COMPAT_X32;
#endif
}
#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;
ap.pages = fuse_pages_alloc(fc->max_pages, GFP_KERNEL, &ap.descs);
iov_page = (struct iovec *) __get_free_page(GFP_KERNEL);
if (!ap.pages || !iov_page)
goto out;
fuse_page_descs_length_init(ap.descs, 0, fc->max_pages);
/*
* 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 > fc->max_pages)
goto out;
while (ap.num_pages < max_pages) {
ap.pages[ap.num_pages] = alloc_page(GFP_KERNEL | __GFP_HIGHMEM);
if (!ap.pages[ap.num_pages])
goto out;
ap.num_pages++;
}
/* okay, let's send it to the client */
ap.args.opcode = FUSE_IOCTL;
ap.args.nodeid = ff->nodeid;
ap.args.in_numargs = 1;
ap.args.in_args[0].size = sizeof(inarg);
ap.args.in_args[0].value = &inarg;
if (in_size) {
ap.args.in_numargs++;
ap.args.in_args[1].size = in_size;
ap.args.in_pages = true;
err = -EFAULT;
iov_iter_init(&ii, WRITE, in_iov, in_iovs, in_size);
for (i = 0; iov_iter_count(&ii) && !WARN_ON(i >= ap.num_pages); i++) {
c = copy_page_from_iter(ap.pages[i], 0, PAGE_SIZE, &ii);
if (c != PAGE_SIZE && iov_iter_count(&ii))
goto out;
}
}
ap.args.out_numargs = 2;
ap.args.out_args[0].size = sizeof(outarg);
ap.args.out_args[0].value = &outarg;
ap.args.out_args[1].size = out_size;
ap.args.out_pages = true;
ap.args.out_argvar = true;
transferred = fuse_simple_request(fc, &ap.args);
err = transferred;
if (transferred < 0)
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(ap.pages[0]);
err = fuse_copy_ioctl_iovec(fc, iov_page, vaddr,
transferred, in_iovs + out_iovs,
(flags & FUSE_IOCTL_COMPAT) != 0);
kunmap_atomic(vaddr);
if (err)
goto out;
in_iov = iov_page;
out_iov = in_iov + in_iovs;
err = fuse_verify_ioctl_iov(fc, in_iov, in_iovs);
if (err)
goto out;
err = fuse_verify_ioctl_iov(fc, out_iov, out_iovs);
if (err)
goto out;
goto retry;
}
err = -EIO;
if (transferred > inarg.out_size)
goto out;
err = -EFAULT;
iov_iter_init(&ii, READ, out_iov, out_iovs, transferred);
for (i = 0; iov_iter_count(&ii) && !WARN_ON(i >= ap.num_pages); i++) {
c = copy_page_to_iter(ap.pages[i], 0, PAGE_SIZE, &ii);
if (c != PAGE_SIZE && iov_iter_count(&ii))
goto out;
}
err = 0;
out:
free_page((unsigned long) iov_page);
while (ap.num_pages)
__free_page(ap.pages[--ap.num_pages]);
kfree(ap.pages);
return err ? err : outarg.result;
}
EXPORT_SYMBOL_GPL(fuse_do_ioctl);
long fuse_ioctl_common(struct file *file, unsigned int cmd,
unsigned long arg, unsigned int flags)
{
struct inode *inode = file_inode(file);
struct fuse_conn *fc = get_fuse_conn(inode);
if (!fuse_allow_current_process(fc))
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_ioctl_common(file, cmd, arg, 0);
}
static long fuse_file_compat_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
return fuse_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, *uninitialized_var(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);
}
__poll_t 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;
FUSE_ARGS(args);
int err;
if (fc->no_poll)
return DEFAULT_POLLMASK;
poll_wait(file, &ff->poll_wait, wait);
inarg.events = mangle_poll(poll_requested_events(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);
}
args.opcode = FUSE_POLL;
args.nodeid = ff->nodeid;
args.in_numargs = 1;
args.in_args[0].size = sizeof(inarg);
args.in_args[0].value = &inarg;
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)
return demangle_poll(outarg.revents);
if (err == -ENOSYS) {
fc->no_poll = 1;
return DEFAULT_POLLMASK;
}
return EPOLLERR;
}
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 void fuse_do_truncate(struct file *file)
{
struct inode *inode = file->f_mapping->host;
struct iattr attr;
attr.ia_valid = ATTR_SIZE;
attr.ia_size = i_size_read(inode);
attr.ia_file = file;
attr.ia_valid |= ATTR_FILE;
fuse_do_setattr(file_dentry(file), &attr, file);
}
static inline loff_t fuse_round_up(struct fuse_conn *fc, loff_t off)
{
return round_up(off, fc->max_pages << PAGE_SHIFT);
}
static ssize_t
fuse_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
{
DECLARE_COMPLETION_ONSTACK(wait);
ssize_t ret = 0;
struct file *file = iocb->ki_filp;
struct fuse_file *ff = file->private_data;
bool async_dio = ff->fc->async_dio;
loff_t pos = 0;
struct inode *inode;
loff_t i_size;
size_t count = iov_iter_count(iter);
loff_t offset = iocb->ki_pos;
struct fuse_io_priv *io;
pos = offset;
inode = file->f_mapping->host;
i_size = i_size_read(inode);
if ((iov_iter_rw(iter) == READ) && (offset > i_size))
return 0;
/* optimization for short read */
if (async_dio && iov_iter_rw(iter) != WRITE && offset + count > i_size) {
if (offset >= i_size)
return 0;
iov_iter_truncate(iter, fuse_round_up(ff->fc, i_size - offset));
count = iov_iter_count(iter);
}
io = kmalloc(sizeof(struct fuse_io_priv), GFP_KERNEL);
if (!io)
return -ENOMEM;
spin_lock_init(&io->lock);
kref_init(&io->refcnt);
io->reqs = 1;
io->bytes = -1;
io->size = 0;
io->offset = offset;
io->write = (iov_iter_rw(iter) == WRITE);
io->err = 0;
/*
* By default, we want to optimize all I/Os with async request
* submission to the client filesystem if supported.
*/
io->async = async_dio;
io->iocb = iocb;
io->blocking = is_sync_kiocb(iocb);
/*
* We cannot asynchronously extend the size of a file.
* In such case the aio will behave exactly like sync io.
*/
if ((offset + count > i_size) && iov_iter_rw(iter) == WRITE)
io->blocking = true;
if (io->async && io->blocking) {
/*
* Additional reference to keep io around after
* calling fuse_aio_complete()
*/
kref_get(&io->refcnt);
io->done = &wait;
}
if (iov_iter_rw(iter) == WRITE) {
ret = fuse_direct_io(io, iter, &pos, FUSE_DIO_WRITE);
fuse_invalidate_attr(inode);
} else {
ret = __fuse_direct_read(io, iter, &pos);
}
if (io->async) {
bool blocking = io->blocking;
fuse_aio_complete(io, ret < 0 ? ret : 0, -1);
/* we have a non-extending, async request, so return */
if (!blocking)
return -EIOCBQUEUED;
wait_for_completion(&wait);
ret = fuse_get_res_by_io(io);
}
kref_put(&io->refcnt, fuse_io_release);
if (iov_iter_rw(iter) == WRITE) {
if (ret > 0)
fuse_write_update_size(inode, pos);
else if (ret < 0 && offset + count > i_size)
fuse_do_truncate(file);
}
return ret;
}
static int fuse_writeback_range(struct inode *inode, loff_t start, loff_t end)
{
int err = filemap_write_and_wait_range(inode->i_mapping, start, end);
if (!err)
fuse_sync_writes(inode);
return err;
}
static long fuse_file_fallocate(struct file *file, int mode, loff_t offset,
loff_t length)
{
struct fuse_file *ff = file->private_data;
struct inode *inode = file_inode(file);
struct fuse_inode *fi = get_fuse_inode(inode);
struct fuse_conn *fc = ff->fc;
FUSE_ARGS(args);
struct fuse_fallocate_in inarg = {
.fh = ff->fh,
.offset = offset,
.length = length,
.mode = mode
};
int err;
bool lock_inode = !(mode & FALLOC_FL_KEEP_SIZE) ||
(mode & FALLOC_FL_PUNCH_HOLE);
if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
return -EOPNOTSUPP;
if (fc->no_fallocate)
return -EOPNOTSUPP;
if (lock_inode) {
inode_lock(inode);
if (mode & FALLOC_FL_PUNCH_HOLE) {
loff_t endbyte = offset + length - 1;
err = fuse_writeback_range(inode, offset, endbyte);
if (err)
goto out;
}
}
if (!(mode & FALLOC_FL_KEEP_SIZE) &&
offset + length > i_size_read(inode)) {
err = inode_newsize_ok(inode, offset + length);
if (err)
goto out;
}
if (!(mode & FALLOC_FL_KEEP_SIZE))
set_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
args.opcode = FUSE_FALLOCATE;
args.nodeid = ff->nodeid;
args.in_numargs = 1;
args.in_args[0].size = sizeof(inarg);
args.in_args[0].value = &inarg;
err = fuse_simple_request(fc, &args);
if (err == -ENOSYS) {
fc->no_fallocate = 1;
err = -EOPNOTSUPP;
}
if (err)
goto out;
/* we could have extended the file */
if (!(mode & FALLOC_FL_KEEP_SIZE)) {
bool changed = fuse_write_update_size(inode, offset + length);
if (changed && fc->writeback_cache)
file_update_time(file);
}
if (mode & FALLOC_FL_PUNCH_HOLE)
truncate_pagecache_range(inode, offset, offset + length - 1);
fuse_invalidate_attr(inode);
out:
if (!(mode & FALLOC_FL_KEEP_SIZE))
clear_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
if (lock_inode)
inode_unlock(inode);
return err;
}
static ssize_t __fuse_copy_file_range(struct file *file_in, loff_t pos_in,
struct file *file_out, loff_t pos_out,
size_t len, unsigned int flags)
{
struct fuse_file *ff_in = file_in->private_data;
struct fuse_file *ff_out = file_out->private_data;
struct inode *inode_in = file_inode(file_in);
struct inode *inode_out = file_inode(file_out);
struct fuse_inode *fi_out = get_fuse_inode(inode_out);
struct fuse_conn *fc = ff_in->fc;
FUSE_ARGS(args);
struct fuse_copy_file_range_in inarg = {
.fh_in = ff_in->fh,
.off_in = pos_in,
.nodeid_out = ff_out->nodeid,
.fh_out = ff_out->fh,
.off_out = pos_out,
.len = len,
.flags = flags
};
struct fuse_write_out outarg;
ssize_t err;
/* mark unstable when write-back is not used, and file_out gets
* extended */
bool is_unstable = (!fc->writeback_cache) &&
((pos_out + len) > inode_out->i_size);
if (fc->no_copy_file_range)
return -EOPNOTSUPP;
if (file_inode(file_in)->i_sb != file_inode(file_out)->i_sb)
return -EXDEV;
if (fc->writeback_cache) {
inode_lock(inode_in);
err = fuse_writeback_range(inode_in, pos_in, pos_in + len);
inode_unlock(inode_in);
if (err)
return err;
}
inode_lock(inode_out);
err = file_modified(file_out);
if (err)
goto out;
if (fc->writeback_cache) {
err = fuse_writeback_range(inode_out, pos_out, pos_out + len);
if (err)
goto out;
}
if (is_unstable)
set_bit(FUSE_I_SIZE_UNSTABLE, &fi_out->state);
args.opcode = FUSE_COPY_FILE_RANGE;
args.nodeid = ff_in->nodeid;
args.in_numargs = 1;
args.in_args[0].size = sizeof(inarg);
args.in_args[0].value = &inarg;
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 == -ENOSYS) {
fc->no_copy_file_range = 1;
err = -EOPNOTSUPP;
}
if (err)
goto out;
if (fc->writeback_cache) {
fuse_write_update_size(inode_out, pos_out + outarg.size);
file_update_time(file_out);
}
fuse_invalidate_attr(inode_out);
err = outarg.size;
out:
if (is_unstable)
clear_bit(FUSE_I_SIZE_UNSTABLE, &fi_out->state);
inode_unlock(inode_out);
file_accessed(file_in);
return err;
}
static ssize_t fuse_copy_file_range(struct file *src_file, loff_t src_off,
struct file *dst_file, loff_t dst_off,
size_t len, unsigned int flags)
{
ssize_t ret;
ret = __fuse_copy_file_range(src_file, src_off, dst_file, dst_off,
len, flags);
if (ret == -EOPNOTSUPP || ret == -EXDEV)
ret = generic_copy_file_range(src_file, src_off, dst_file,
dst_off, len, flags);
return ret;
}
static const struct file_operations fuse_file_operations = {
.llseek = fuse_file_llseek,
.read_iter = fuse_file_read_iter,
.write_iter = fuse_file_write_iter,
.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,
.splice_write = iter_file_splice_write,
.unlocked_ioctl = fuse_file_ioctl,
.compat_ioctl = fuse_file_compat_ioctl,
.poll = fuse_file_poll,
.fallocate = fuse_file_fallocate,
.copy_file_range = fuse_copy_file_range,
};
static const struct address_space_operations fuse_file_aops = {
.readpage = fuse_readpage,
.writepage = fuse_writepage,
.writepages = fuse_writepages,
.launder_page = fuse_launder_page,
.readpages = fuse_readpages,
.set_page_dirty = __set_page_dirty_nobuffers,
.bmap = fuse_bmap,
.direct_IO = fuse_direct_IO,
.write_begin = fuse_write_begin,
.write_end = fuse_write_end,
};
void fuse_init_file_inode(struct inode *inode)
{
struct fuse_inode *fi = get_fuse_inode(inode);
inode->i_fop = &fuse_file_operations;
inode->i_data.a_ops = &fuse_file_aops;
INIT_LIST_HEAD(&fi->write_files);
INIT_LIST_HEAD(&fi->queued_writes);
fi->writectr = 0;
init_waitqueue_head(&fi->page_waitq);
INIT_LIST_HEAD(&fi->writepages);
}
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