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linuxdebug/fs/fuse/file.c

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null pointer error
2024-07-16 15:50:57 +02:00
/*
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/swap.h>
#include <linux/falloc.h>
#include <linux/uio.h>
#include <linux/fs.h>
static int fuse_send_open(struct fuse_mount *fm, u64 nodeid,
unsigned int open_flags, int opcode,
struct fuse_open_out *outargp)
{
struct fuse_open_in inarg;
FUSE_ARGS(args);
memset(&inarg, 0, sizeof(inarg));
inarg.flags = open_flags & ~(O_CREAT | O_EXCL | O_NOCTTY);
if (!fm->fc->atomic_o_trunc)
inarg.flags &= ~O_TRUNC;
if (fm->fc->handle_killpriv_v2 &&
(inarg.flags & O_TRUNC) && !capable(CAP_FSETID)) {
inarg.open_flags |= FUSE_OPEN_KILL_SUIDGID;
}
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(fm, &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_mount *fm)
{
struct fuse_file *ff;
ff = kzalloc(sizeof(struct fuse_file), GFP_KERNEL_ACCOUNT);
if (unlikely(!ff))
return NULL;
ff->fm = fm;
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(&fm->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_mount *fm, 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->fm->fc->no_opendir : ff->fm->fc->no_open) {
/* Do nothing when client does not implement 'open' */
fuse_release_end(ff->fm, args, 0);
} else if (sync) {
fuse_simple_request(ff->fm, args);
fuse_release_end(ff->fm, args, 0);
} else {
args->end = fuse_release_end;
if (fuse_simple_background(ff->fm, args,
GFP_KERNEL | __GFP_NOFAIL))
fuse_release_end(ff->fm, args, -ENOTCONN);
}
kfree(ff);
}
}
struct fuse_file *fuse_file_open(struct fuse_mount *fm, u64 nodeid,
unsigned int open_flags, bool isdir)
{
struct fuse_conn *fc = fm->fc;
struct fuse_file *ff;
int opcode = isdir ? FUSE_OPENDIR : FUSE_OPEN;
ff = fuse_file_alloc(fm);
if (!ff)
return ERR_PTR(-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(fm, nodeid, open_flags, opcode, &outarg);
if (!err) {
ff->fh = outarg.fh;
ff->open_flags = outarg.open_flags;
} else if (err != -ENOSYS) {
fuse_file_free(ff);
return ERR_PTR(err);
} else {
if (isdir)
fc->no_opendir = 1;
else
fc->no_open = 1;
}
}
if (isdir)
ff->open_flags &= ~FOPEN_DIRECT_IO;
ff->nodeid = nodeid;
return ff;
}
int fuse_do_open(struct fuse_mount *fm, u64 nodeid, struct file *file,
bool isdir)
{
struct fuse_file *ff = fuse_file_open(fm, nodeid, file->f_flags, isdir);
if (!IS_ERR(ff))
file->private_data = ff;
return PTR_ERR_OR_ZERO(ff);
}
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_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);
file_update_time(file);
fuse_invalidate_attr_mask(inode, FUSE_STATX_MODSIZE);
}
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_mount *fm = get_fuse_mount(inode);
struct fuse_conn *fc = fm->fc;
int err;
bool is_wb_truncate = (file->f_flags & O_TRUNC) &&
fc->atomic_o_trunc &&
fc->writeback_cache;
bool dax_truncate = (file->f_flags & O_TRUNC) &&
fc->atomic_o_trunc && FUSE_IS_DAX(inode);
if (fuse_is_bad(inode))
return -EIO;
err = generic_file_open(inode, file);
if (err)
return err;
if (is_wb_truncate || dax_truncate)
inode_lock(inode);
if (dax_truncate) {
filemap_invalidate_lock(inode->i_mapping);
err = fuse_dax_break_layouts(inode, 0, 0);
if (err)
goto out_inode_unlock;
}
if (is_wb_truncate || dax_truncate)
fuse_set_nowrite(inode);
err = fuse_do_open(fm, get_node_id(inode), file, isdir);
if (!err)
fuse_finish_open(inode, file);
if (is_wb_truncate || dax_truncate)
fuse_release_nowrite(inode);
if (!err) {
struct fuse_file *ff = file->private_data;
if (fc->atomic_o_trunc && (file->f_flags & O_TRUNC))
truncate_pagecache(inode, 0);
else if (!(ff->open_flags & FOPEN_KEEP_CACHE))
invalidate_inode_pages2(inode->i_mapping);
}
if (dax_truncate)
filemap_invalidate_unlock(inode->i_mapping);
out_inode_unlock:
if (is_wb_truncate || dax_truncate)
inode_unlock(inode);
return err;
}
static void fuse_prepare_release(struct fuse_inode *fi, struct fuse_file *ff,
unsigned int flags, int opcode)
{
struct fuse_conn *fc = ff->fm->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_file_release(struct inode *inode, struct fuse_file *ff,
unsigned int open_flags, fl_owner_t id, bool isdir)
{
struct fuse_inode *fi = get_fuse_inode(inode);
struct fuse_release_args *ra = ff->release_args;
int opcode = isdir ? FUSE_RELEASEDIR : FUSE_RELEASE;
fuse_prepare_release(fi, ff, open_flags, opcode);
if (ff->flock) {
ra->inarg.release_flags |= FUSE_RELEASE_FLOCK_UNLOCK;
ra->inarg.lock_owner = fuse_lock_owner_id(ff->fm->fc, id);
}
/* Hold inode until release is finished */
ra->inode = igrab(inode);
/*
* 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->fm->fc->destroy, isdir);
}
void fuse_release_common(struct file *file, bool isdir)
{
fuse_file_release(file_inode(file), file->private_data, file->f_flags,
(fl_owner_t) file, 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);
/*
* Dirty pages might remain despite write_inode_now() call from
* fuse_flush() due to writes racing with the close.
*/
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,
unsigned 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 rb_node writepages_entry;
struct list_head queue_entry;
struct fuse_writepage_args *next;
struct inode *inode;
struct fuse_sync_bucket *bucket;
};
static struct fuse_writepage_args *fuse_find_writeback(struct fuse_inode *fi,
pgoff_t idx_from, pgoff_t idx_to)
{
struct rb_node *n;
n = fi->writepages.rb_node;
while (n) {
struct fuse_writepage_args *wpa;
pgoff_t curr_index;
wpa = rb_entry(n, struct fuse_writepage_args, writepages_entry);
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)
n = n->rb_right;
else if (idx_to < curr_index)
n = n->rb_left;
else
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_mount *fm = get_fuse_mount(inode);
struct fuse_file *ff = file->private_data;
struct fuse_flush_in inarg;
FUSE_ARGS(args);
int err;
if (fuse_is_bad(inode))
return -EIO;
if (ff->open_flags & FOPEN_NOFLUSH && !fm->fc->writeback_cache)
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;
err = 0;
if (fm->fc->no_flush)
goto inval_attr_out;
memset(&inarg, 0, sizeof(inarg));
inarg.fh = ff->fh;
inarg.lock_owner = fuse_lock_owner_id(fm->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(fm, &args);
if (err == -ENOSYS) {
fm->fc->no_flush = 1;
err = 0;
}
inval_attr_out:
/*
* In memory i_blocks is not maintained by fuse, if writeback cache is
* enabled, i_blocks from cached attr may not be accurate.
*/
if (!err && fm->fc->writeback_cache)
fuse_invalidate_attr_mask(inode, STATX_BLOCKS);
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_mount *fm = get_fuse_mount(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(fm, &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 (fuse_is_bad(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 split 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);
}
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_mount *fm, 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_mount *fm,
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;
ia->ap.args.may_block = io->should_dirty;
err = fuse_simple_background(fm, &ia->ap.args, GFP_KERNEL);
if (err)
fuse_aio_complete_req(fm, &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_mount *fm = ff->fm;
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(fm->fc, owner);
}
if (ia->io->async)
return fuse_async_req_send(fm, ia, count);
return fuse_simple_request(fm, &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 writeback_cache is enabled, a short read means there's a hole in
* the file. Some data after the hole is in page cache, but has not
* reached the client fs yet. So the hole is not present there.
*/
if (!fc->writeback_cache) {
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_mount *fm = get_fuse_mount(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(fm->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(fm, &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_read_folio(struct file *file, struct folio *folio)
{
struct page *page = &folio->page;
struct inode *inode = page->mapping->host;
int err;
err = -EIO;
if (fuse_is_bad(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_mount *fm, 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_mount *fm = ff->fm;
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(fm->fc);
if (fm->fc->async_read) {
ia->ff = fuse_file_get(ff);
ap->args.end = fuse_readpages_end;
err = fuse_simple_background(fm, &ap->args, GFP_KERNEL);
if (!err)
return;
} else {
res = fuse_simple_request(fm, &ap->args);
err = res < 0 ? res : 0;
}
fuse_readpages_end(fm, &ap->args, err);
}
static void fuse_readahead(struct readahead_control *rac)
{
struct inode *inode = rac->mapping->host;
struct fuse_conn *fc = get_fuse_conn(inode);
unsigned int i, max_pages, nr_pages = 0;
if (fuse_is_bad(inode))
return;
max_pages = min_t(unsigned int, fc->max_pages,
fc->max_read / PAGE_SIZE);
for (;;) {
struct fuse_io_args *ia;
struct fuse_args_pages *ap;
if (fc->num_background >= fc->congestion_threshold &&
rac->ra->async_size >= readahead_count(rac))
/*
* Congested and only async pages left, so skip the
* rest.
*/
break;
nr_pages = readahead_count(rac) - nr_pages;
if (nr_pages > max_pages)
nr_pages = max_pages;
if (nr_pages == 0)
break;
ia = fuse_io_alloc(NULL, nr_pages);
if (!ia)
return;
ap = &ia->ap;
nr_pages = __readahead_batch(rac, ap->pages, nr_pages);
for (i = 0; i < nr_pages; i++) {
fuse_wait_on_page_writeback(inode,
readahead_index(rac) + i);
ap->descs[i].length = PAGE_SIZE;
}
ap->num_pages = nr_pages;
fuse_send_readpages(ia, rac->file);
}
}
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, STATX_SIZE);
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->fm->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_is_dsync(iocb))
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_mount *fm = ff->fm;
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(fm->fc, owner);
}
if (ia->io->async)
return fuse_async_req_send(fm, ia, count);
err = fuse_simple_request(fm, &ia->ap.args);
if (!err && ia->write.out.size > count)
err = -EIO;
return err ?: ia->write.out.size;
}
bool fuse_write_update_attr(struct inode *inode, loff_t pos, ssize_t written)
{
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 (written > 0 && pos > inode->i_size) {
i_size_write(inode, pos);
ret = true;
}
spin_unlock(&fi->lock);
fuse_invalidate_attr_mask(inode, FUSE_STATX_MODSIZE);
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_mount *fm = ff->fm;
unsigned int offset, i;
bool short_write;
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);
if (fm->fc->handle_killpriv_v2 && !capable(CAP_FSETID))
ia->write.in.write_flags |= FUSE_WRITE_KILL_SUIDGID;
err = fuse_simple_request(fm, &ap->args);
if (!err && ia->write.out.size > count)
err = -EIO;
short_write = ia->write.out.size < count;
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) {
ClearPageUptodate(page);
} else {
if (count >= PAGE_SIZE - offset)
count -= PAGE_SIZE - offset;
else {
if (short_write)
ClearPageUptodate(page);
count = 0;
}
offset = 0;
}
if (ia->write.page_locked && (i == ap->num_pages - 1))
unlock_page(page);
put_page(page);
}
return err;
}
static ssize_t fuse_fill_write_pages(struct fuse_io_args *ia,
struct address_space *mapping,
struct iov_iter *ii, loff_t pos,
unsigned int max_pages)
{
struct fuse_args_pages *ap = &ia->ap;
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 (fault_in_iov_iter_readable(ii, bytes))
break;
err = -ENOMEM;
page = grab_cache_page_write_begin(mapping, index);
if (!page)
break;
if (mapping_writably_mapped(mapping))
flush_dcache_page(page);
tmp = copy_page_from_iter_atomic(page, offset, bytes, ii);
flush_dcache_page(page);
if (!tmp) {
unlock_page(page);
put_page(page);
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 we copied full page, mark it uptodate */
if (tmp == PAGE_SIZE)
SetPageUptodate(page);
if (PageUptodate(page)) {
unlock_page(page);
} else {
ia->write.page_locked = true;
break;
}
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(&ia, 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));
fuse_write_update_attr(inode, pos, res);
clear_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
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;
struct fuse_conn *fc = get_fuse_conn(inode);
loff_t endbyte = 0;
if (fc->writeback_cache) {
/* Update size (EOF optimization) and mode (SUID clearing) */
err = fuse_update_attributes(mapping->host, file,
STATX_SIZE | STATX_MODE);
if (err)
return err;
if (fc->handle_killpriv_v2 &&
setattr_should_drop_suidgid(&init_user_ns, file_inode(file))) {
goto writethrough;
}
return generic_file_write_iter(iocb, from);
}
writethrough:
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 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_pages2(ii, &ap->pages[ap->num_pages],
*nbytesp - nbytes,
max_pages - ap->num_pages,
&start);
if (ret < 0)
break;
nbytes += ret;
ret += start;
npages = DIV_ROUND_UP(ret, 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);
}
ap->args.user_pages = true;
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->fm->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;
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 && user_backed_iter(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_SUIDGID;
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_write_update_attr(inode, iocb->ki_pos, res);
}
}
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;
struct inode *inode = file_inode(file);
if (fuse_is_bad(inode))
return -EIO;
if (FUSE_IS_DAX(inode))
return fuse_dax_read_iter(iocb, to);
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;
struct inode *inode = file_inode(file);
if (fuse_is_bad(inode))
return -EIO;
if (FUSE_IS_DAX(inode))
return fuse_dax_write_iter(iocb, from);
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;
if (wpa->bucket)
fuse_sync_bucket_dec(wpa->bucket);
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_mount *fm,
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;
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_mount *fm,
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(fm, args, GFP_ATOMIC);
if (err == -ENOMEM) {
spin_unlock(&fi->lock);
err = fuse_simple_background(fm, 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--;
rb_erase(&wpa->writepages_entry, &fi->writepages);
fuse_writepage_finish(fm, 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_mount *fm = get_fuse_mount(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(fm, wpa, crop);
}
}
static struct fuse_writepage_args *fuse_insert_writeback(struct rb_root *root,
struct fuse_writepage_args *wpa)
{
pgoff_t idx_from = wpa->ia.write.in.offset >> PAGE_SHIFT;
pgoff_t idx_to = idx_from + wpa->ia.ap.num_pages - 1;
struct rb_node **p = &root->rb_node;
struct rb_node *parent = NULL;
WARN_ON(!wpa->ia.ap.num_pages);
while (*p) {
struct fuse_writepage_args *curr;
pgoff_t curr_index;
parent = *p;
curr = rb_entry(parent, struct fuse_writepage_args,
writepages_entry);
WARN_ON(curr->inode != wpa->inode);
curr_index = curr->ia.write.in.offset >> PAGE_SHIFT;
if (idx_from >= curr_index + curr->ia.ap.num_pages)
p = &(*p)->rb_right;
else if (idx_to < curr_index)
p = &(*p)->rb_left;
else
return curr;
}
rb_link_node(&wpa->writepages_entry, parent, p);
rb_insert_color(&wpa->writepages_entry, root);
return NULL;
}
static void tree_insert(struct rb_root *root, struct fuse_writepage_args *wpa)
{
WARN_ON(fuse_insert_writeback(root, wpa));
}
static void fuse_writepage_end(struct fuse_mount *fm, 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);
struct fuse_conn *fc = get_fuse_conn(inode);
mapping_set_error(inode->i_mapping, error);
/*
* A writeback finished and this might have updated mtime/ctime on
* server making local mtime/ctime stale. Hence invalidate attrs.
* Do this only if writeback_cache is not enabled. If writeback_cache
* is enabled, we trust local ctime/mtime.
*/
if (!fc->writeback_cache)
fuse_invalidate_attr_mask(inode, FUSE_STATX_MODIFY);
spin_lock(&fi->lock);
rb_erase(&wpa->writepages_entry, &fi->writepages);
while (wpa->next) {
struct fuse_mount *fm = get_fuse_mount(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);
tree_insert(&fi->writepages, next);
/*
* 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(fm, next, inarg->offset + inarg->size);
}
fi->writectr--;
fuse_writepage_finish(fm, wpa);
spin_unlock(&fi->lock);
fuse_writepage_free(wpa);
}
static struct fuse_file *__fuse_write_file_get(struct fuse_inode *fi)
{
struct fuse_file *ff;
spin_lock(&fi->lock);
ff = list_first_entry_or_null(&fi->write_files, struct fuse_file,
write_entry);
if (ff)
fuse_file_get(ff);
spin_unlock(&fi->lock);
return ff;
}
static struct fuse_file *fuse_write_file_get(struct fuse_inode *fi)
{
struct fuse_file *ff = __fuse_write_file_get(fi);
WARN_ON(!ff);
return ff;
}
int fuse_write_inode(struct inode *inode, struct writeback_control *wbc)
{
struct fuse_inode *fi = get_fuse_inode(inode);
struct fuse_file *ff;
int err;
/*
* Inode is always written before the last reference is dropped and
* hence this should not be reached from reclaim.
*
* Writing back the inode from reclaim can deadlock if the request
* processing itself needs an allocation. Allocations triggering
* reclaim while serving a request can't be prevented, because it can
* involve any number of unrelated userspace processes.
*/
WARN_ON(wbc->for_reclaim);
ff = __fuse_write_file_get(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 void fuse_writepage_add_to_bucket(struct fuse_conn *fc,
struct fuse_writepage_args *wpa)
{
if (!fc->sync_fs)
return;
rcu_read_lock();
/* Prevent resurrection of dead bucket in unlikely race with syncfs */
do {
wpa->bucket = rcu_dereference(fc->curr_bucket);
} while (unlikely(!atomic_inc_not_zero(&wpa->bucket->count)));
rcu_read_unlock();
}
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(fi);
if (!wpa->ia.ff)
goto err_nofile;
fuse_writepage_add_to_bucket(fc, wpa);
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);
tree_insert(&fi->writepages, wpa);
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)
{
struct fuse_conn *fc = get_fuse_conn(page->mapping->host);
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;
}
if (wbc->sync_mode == WB_SYNC_NONE &&
fc->num_background >= fc->congestion_threshold)
return AOP_WRITEPAGE_ACTIVATE;
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]);
}
/*
* Check under fi->lock if the page is under writeback, and insert it onto the
* rb_tree if not. Otherwise 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
* swapping the new temp page with the old one.
*/
static bool fuse_writepage_add(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);
new_ap->num_pages = 1;
spin_lock(&fi->lock);
old_wpa = fuse_insert_writeback(&fi->writepages, new_wpa);
if (!old_wpa) {
spin_unlock(&fi->lock);
return true;
}
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 false;
}
static bool fuse_writepage_need_send(struct fuse_conn *fc, struct page *page,
struct fuse_args_pages *ap,
struct fuse_fill_wb_data *data)
{
WARN_ON(!ap->num_pages);
/*
* 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.
*/
if (fuse_page_is_writeback(data->inode, page->index))
return true;
/* Reached max pages */
if (ap->num_pages == fc->max_pages)
return true;
/* Reached max write bytes */
if ((ap->num_pages + 1) * PAGE_SIZE > fc->max_write)
return true;
/* Discontinuity */
if (data->orig_pages[ap->num_pages - 1]->index + 1 != page->index)
return true;
/* Need to grow the pages array? If so, did the expansion fail? */
if (ap->num_pages == data->max_pages && !fuse_pages_realloc(data))
return true;
return false;
}
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;
int err;
if (!data->ff) {
err = -EIO;
data->ff = fuse_write_file_get(fi);
if (!data->ff)
goto out_unlock;
}
if (wpa && fuse_writepage_need_send(fc, page, ap, 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;
}
fuse_writepage_add_to_bucket(fc, wpa);
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;
}
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;
data->orig_pages[ap->num_pages] = page;
inc_wb_stat(&inode_to_bdi(inode)->wb, WB_WRITEBACK);
inc_node_page_state(tmp_page, NR_WRITEBACK_TEMP);
err = 0;
if (data->wpa) {
/*
* Protected by fi->lock against concurrent access by
* fuse_page_is_writeback().
*/
spin_lock(&fi->lock);
ap->num_pages++;
spin_unlock(&fi->lock);
} else if (fuse_writepage_add(wpa, page)) {
data->wpa = wpa;
} else {
end_page_writeback(page);
}
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 (fuse_is_bad(inode))
goto out;
if (wbc->sync_mode == WB_SYNC_NONE &&
fc->num_background >= fc->congestion_threshold)
return 0;
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) {
WARN_ON(!data.wpa->ia.ap.num_pages);
fuse_writepages_send(&data);
}
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, 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);
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;
pos += copied;
if (!PageUptodate(page)) {
/* Zero any unwritten bytes at the end of the page */
size_t endoff = pos & ~PAGE_MASK;
if (endoff)
zero_user_segment(page, endoff, PAGE_SIZE);
SetPageUptodate(page);
}
if (pos > inode->i_size)
i_size_write(inode, pos);
set_page_dirty(page);
unlock:
unlock_page(page);
put_page(page);
return copied;
}
static int fuse_launder_folio(struct folio *folio)
{
int err = 0;
if (folio_clear_dirty_for_io(folio)) {
struct inode *inode = folio->mapping->host;
/* Serialize with pending writeback for the same page */
fuse_wait_on_page_writeback(inode, folio->index);
err = fuse_writepage_locked(&folio->page);
if (!err)
fuse_wait_on_page_writeback(inode, folio->index);
}
return err;
}
/*
* Write back dirty data/metadata now (there may not be any suitable
* open files later for data)
*/
static void fuse_vma_close(struct vm_area_struct *vma)
{
int err;
err = write_inode_now(vma->vm_file->f_mapping->host, 1);
mapping_set_error(vma->vm_file->f_mapping, err);
}
/*
* 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;
/* DAX mmap is superior to direct_io mmap */
if (FUSE_IS_DAX(file_inode(file)))
return fuse_dax_mmap(file, vma);
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_mount *fm = get_fuse_mount(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(fm, &args);
if (!err)
err = convert_fuse_file_lock(fm->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_mount *fm = get_fuse_mount(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, fm->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(fm, &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_mount *fm = get_fuse_mount(inode);
FUSE_ARGS(args);
struct fuse_bmap_in inarg;
struct fuse_bmap_out outarg;
int err;
if (!inode->i_sb->s_bdev || fm->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(fm, &args);
if (err == -ENOSYS)
fm->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_mount *fm = get_fuse_mount(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 (fm->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(fm, &args);
if (err) {
if (err == -ENOSYS) {
fm->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, STATX_SIZE);
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, STATX_SIZE);
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;
}
/*
* 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);
}
__poll_t fuse_file_poll(struct file *file, poll_table *wait)
{
struct fuse_file *ff = file->private_data;
struct fuse_mount *fm = ff->fm;
struct fuse_poll_in inarg = { .fh = ff->fh, .kh = ff->kh };
struct fuse_poll_out outarg;
FUSE_ARGS(args);
int err;
if (fm->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(fm->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(fm, &args);
if (!err)
return demangle_poll(outarg.revents);
if (err == -ENOSYS) {
fm->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;
loff_t pos = 0;
struct inode *inode;
loff_t i_size;
size_t count = iov_iter_count(iter), shortened = 0;
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;
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 = ff->fm->fc->async_dio;
io->iocb = iocb;
io->blocking = is_sync_kiocb(iocb);
/* optimization for short read */
if (io->async && !io->write && offset + count > i_size) {
iov_iter_truncate(iter, fuse_round_up(ff->fm->fc, i_size - offset));
shortened = count - iov_iter_count(iter);
count -= shortened;
}
/*
* 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) && io->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_mask(inode, FUSE_STATX_MODSIZE);
} else {
ret = __fuse_direct_read(io, iter, &pos);
}
iov_iter_reexpand(iter, iov_iter_count(iter) + shortened);
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) {
fuse_write_update_attr(inode, pos, ret);
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, LLONG_MAX);
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_mount *fm = ff->fm;
FUSE_ARGS(args);
struct fuse_fallocate_in inarg = {
.fh = ff->fh,
.offset = offset,
.length = length,
.mode = mode
};
int err;
bool block_faults = FUSE_IS_DAX(inode) &&
(!(mode & FALLOC_FL_KEEP_SIZE) ||
(mode & (FALLOC_FL_PUNCH_HOLE | FALLOC_FL_ZERO_RANGE)));
if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE |
FALLOC_FL_ZERO_RANGE))
return -EOPNOTSUPP;
if (fm->fc->no_fallocate)
return -EOPNOTSUPP;
inode_lock(inode);
if (block_faults) {
filemap_invalidate_lock(inode->i_mapping);
err = fuse_dax_break_layouts(inode, 0, 0);
if (err)
goto out;
}
if (mode & (FALLOC_FL_PUNCH_HOLE | FALLOC_FL_ZERO_RANGE)) {
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;
}
err = file_modified(file);
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(fm, &args);
if (err == -ENOSYS) {
fm->fc->no_fallocate = 1;
err = -EOPNOTSUPP;
}
if (err)
goto out;
/* we could have extended the file */
if (!(mode & FALLOC_FL_KEEP_SIZE)) {
if (fuse_write_update_attr(inode, offset + length, length))
file_update_time(file);
}
if (mode & (FALLOC_FL_PUNCH_HOLE | FALLOC_FL_ZERO_RANGE))
truncate_pagecache_range(inode, offset, offset + length - 1);
fuse_invalidate_attr_mask(inode, FUSE_STATX_MODSIZE);
out:
if (!(mode & FALLOC_FL_KEEP_SIZE))
clear_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
if (block_faults)
filemap_invalidate_unlock(inode->i_mapping);
inode_unlock(inode);
fuse_flush_time_update(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_mount *fm = ff_in->fm;
struct fuse_conn *fc = fm->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;
inode_lock(inode_in);
err = fuse_writeback_range(inode_in, pos_in, pos_in + len - 1);
inode_unlock(inode_in);
if (err)
return err;
inode_lock(inode_out);
err = file_modified(file_out);
if (err)
goto out;
/*
* Write out dirty pages in the destination file before sending the COPY
* request to userspace. After the request is completed, truncate off
* pages (including partial ones) from the cache that have been copied,
* since these contain stale data at that point.
*
* This should be mostly correct, but if the COPY writes to partial
* pages (at the start or end) and the parts not covered by the COPY are
* written through a memory map after calling fuse_writeback_range(),
* then these partial page modifications will be lost on truncation.
*
* It is unlikely that someone would rely on such mixed style
* modifications. Yet this does give less guarantees than if the
* copying was performed with write(2).
*
* To fix this a mapping->invalidate_lock could be used to prevent new
* faults while the copy is ongoing.
*/
err = fuse_writeback_range(inode_out, pos_out, pos_out + len - 1);
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(fm, &args);
if (err == -ENOSYS) {
fc->no_copy_file_range = 1;
err = -EOPNOTSUPP;
}
if (err)
goto out;
truncate_inode_pages_range(inode_out->i_mapping,
ALIGN_DOWN(pos_out, PAGE_SIZE),
ALIGN(pos_out + outarg.size, PAGE_SIZE) - 1);
file_update_time(file_out);
fuse_write_update_attr(inode_out, pos_out + outarg.size, outarg.size);
err = outarg.size;
out:
if (is_unstable)
clear_bit(FUSE_I_SIZE_UNSTABLE, &fi_out->state);
inode_unlock(inode_out);
file_accessed(file_in);
fuse_flush_time_update(inode_out);
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,
.get_unmapped_area = thp_get_unmapped_area,
.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 = {
.read_folio = fuse_read_folio,
.readahead = fuse_readahead,
.writepage = fuse_writepage,
.writepages = fuse_writepages,
.launder_folio = fuse_launder_folio,
.dirty_folio = filemap_dirty_folio,
.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, unsigned int flags)
{
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);
fi->writepages = RB_ROOT;
if (IS_ENABLED(CONFIG_FUSE_DAX))
fuse_dax_inode_init(inode, flags);
}