// SPDX-License-Identifier: GPL-2.0-only
/*
* This file contians vfs file ops for 9P2000.
*
* Copyright (C) 2004 by Eric Van Hensbergen <[email protected]>
* Copyright (C) 2002 by Ron Minnich <[email protected]>
*/
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/filelock.h>
#include <linux/sched.h>
#include <linux/file.h>
#include <linux/stat.h>
#include <linux/string.h>
#include <linux/list.h>
#include <linux/pagemap.h>
#include <linux/utsname.h>
#include <linux/uaccess.h>
#include <linux/uio.h>
#include <linux/slab.h>
#include <net/9p/9p.h>
#include <net/9p/client.h>
#include "v9fs.h"
#include "v9fs_vfs.h"
#include "fid.h"
#include "cache.h"
static const struct vm_operations_struct v9fs_mmap_file_vm_ops;
/**
* v9fs_file_open - open a file (or directory)
* @inode: inode to be opened
* @file: file being opened
*
*/
int v9fs_file_open(struct inode *inode, struct file *file)
{
int err;
struct v9fs_session_info *v9ses;
struct p9_fid *fid;
int omode;
p9_debug(P9_DEBUG_VFS, "inode: %p file: %p\n", inode, file);
v9ses = v9fs_inode2v9ses(inode);
if (v9fs_proto_dotl(v9ses))
omode = v9fs_open_to_dotl_flags(file->f_flags);
else
omode = v9fs_uflags2omode(file->f_flags,
v9fs_proto_dotu(v9ses));
fid = file->private_data;
if (!fid) {
fid = v9fs_fid_clone(file_dentry(file));
if (IS_ERR(fid))
return PTR_ERR(fid);
if ((v9ses->cache & CACHE_WRITEBACK) && (omode & P9_OWRITE)) {
int writeback_omode = (omode & ~P9_OWRITE) | P9_ORDWR;
p9_debug(P9_DEBUG_CACHE, "write-only file with writeback enabled, try opening O_RDWR\n");
err = p9_client_open(fid, writeback_omode);
if (err < 0) {
p9_debug(P9_DEBUG_CACHE, "could not open O_RDWR, disabling caches\n");
err = p9_client_open(fid, omode);
fid->mode |= P9L_DIRECT;
}
} else {
err = p9_client_open(fid, omode);
}
if (err < 0) {
p9_fid_put(fid);
return err;
}
if ((file->f_flags & O_APPEND) &&
(!v9fs_proto_dotu(v9ses) && !v9fs_proto_dotl(v9ses)))
generic_file_llseek(file, 0, SEEK_END);
file->private_data = fid;
}
#ifdef CONFIG_9P_FSCACHE
if (v9ses->cache & CACHE_FSCACHE)
fscache_use_cookie(v9fs_inode_cookie(V9FS_I(inode)),
file->f_mode & FMODE_WRITE);
#endif
v9fs_fid_add_modes(fid, v9ses->flags, v9ses->cache, file->f_flags);
v9fs_open_fid_add(inode, &fid);
return 0;
}
/**
* v9fs_file_lock - lock a file (or directory)
* @filp: file to be locked
* @cmd: lock command
* @fl: file lock structure
*
* Bugs: this looks like a local only lock, we should extend into 9P
* by using open exclusive
*/
static int v9fs_file_lock(struct file *filp, int cmd, struct file_lock *fl)
{
struct inode *inode = file_inode(filp);
p9_debug(P9_DEBUG_VFS, "filp: %p lock: %p\n", filp, fl);
if ((IS_SETLK(cmd) || IS_SETLKW(cmd)) && fl->c.flc_type != F_UNLCK) {
filemap_write_and_wait(inode->i_mapping);
invalidate_mapping_pages(&inode->i_data, 0, -1);
}
return 0;
}
static int v9fs_file_do_lock(struct file *filp, int cmd, struct file_lock *fl)
{
struct p9_flock flock;
struct p9_fid *fid;
uint8_t status = P9_LOCK_ERROR;
int res = 0;
struct v9fs_session_info *v9ses;
fid = filp->private_data;
BUG_ON(fid == NULL);
BUG_ON((fl->c.flc_flags & FL_POSIX) != FL_POSIX);
res = locks_lock_file_wait(filp, fl);
if (res < 0)
goto out;
/* convert posix lock to p9 tlock args */
memset(&flock, 0, sizeof(flock));
/* map the lock type */
switch (fl->c.flc_type) {
case F_RDLCK:
flock.type = P9_LOCK_TYPE_RDLCK;
break;
case F_WRLCK:
flock.type = P9_LOCK_TYPE_WRLCK;
break;
case F_UNLCK:
flock.type = P9_LOCK_TYPE_UNLCK;
break;
}
flock.start = fl->fl_start;
if (fl->fl_end == OFFSET_MAX)
flock.length = 0;
else
flock.length = fl->fl_end - fl->fl_start + 1;
flock.proc_id = fl->c.flc_pid;
flock.client_id = fid->clnt->name;
if (IS_SETLKW(cmd))
flock.flags = P9_LOCK_FLAGS_BLOCK;
v9ses = v9fs_inode2v9ses(file_inode(filp));
/*
* if its a blocked request and we get P9_LOCK_BLOCKED as the status
* for lock request, keep on trying
*/
for (;;) {
res = p9_client_lock_dotl(fid, &flock, &status);
if (res < 0)
goto out_unlock;
if (status != P9_LOCK_BLOCKED)
break;
if (status == P9_LOCK_BLOCKED && !IS_SETLKW(cmd))
break;
if (schedule_timeout_interruptible(v9ses->session_lock_timeout)
!= 0)
break;
/*
* p9_client_lock_dotl overwrites flock.client_id with the
* server message, free and reuse the client name
*/
if (flock.client_id != fid->clnt->name) {
kfree(flock.client_id);
flock.client_id = fid->clnt->name;
}
}
/* map 9p status to VFS status */
switch (status) {
case P9_LOCK_SUCCESS:
res = 0;
break;
case P9_LOCK_BLOCKED:
res = -EAGAIN;
break;
default:
WARN_ONCE(1, "unknown lock status code: %d\n", status);
fallthrough;
case P9_LOCK_ERROR:
case P9_LOCK_GRACE:
res = -ENOLCK;
break;
}
out_unlock:
/*
* incase server returned error for lock request, revert
* it locally
*/
if (res < 0 && fl->c.flc_type != F_UNLCK) {
unsigned char type = fl->c.flc_type;
fl->c.flc_type = F_UNLCK;
/* Even if this fails we want to return the remote error */
locks_lock_file_wait(filp, fl);
fl->c.flc_type = type;
}
if (flock.client_id != fid->clnt->name)
kfree(flock.client_id);
out:
return res;
}
static int v9fs_file_getlock(struct file *filp, struct file_lock *fl)
{
struct p9_getlock glock;
struct p9_fid *fid;
int res = 0;
fid = filp->private_data;
BUG_ON(fid == NULL);
posix_test_lock(filp, fl);
/*
* if we have a conflicting lock locally, no need to validate
* with server
*/
if (fl->c.flc_type != F_UNLCK)
return res;
/* convert posix lock to p9 tgetlock args */
memset(&glock, 0, sizeof(glock));
glock.type = P9_LOCK_TYPE_UNLCK;
glock.start = fl->fl_start;
if (fl->fl_end == OFFSET_MAX)
glock.length = 0;
else
glock.length = fl->fl_end - fl->fl_start + 1;
glock.proc_id = fl->c.flc_pid;
glock.client_id = fid->clnt->name;
res = p9_client_getlock_dotl(fid, &glock);
if (res < 0)
goto out;
/* map 9p lock type to os lock type */
switch (glock.type) {
case P9_LOCK_TYPE_RDLCK:
fl->c.flc_type = F_RDLCK;
break;
case P9_LOCK_TYPE_WRLCK:
fl->c.flc_type = F_WRLCK;
break;
case P9_LOCK_TYPE_UNLCK:
fl->c.flc_type = F_UNLCK;
break;
}
if (glock.type != P9_LOCK_TYPE_UNLCK) {
fl->fl_start = glock.start;
if (glock.length == 0)
fl->fl_end = OFFSET_MAX;
else
fl->fl_end = glock.start + glock.length - 1;
fl->c.flc_pid = -glock.proc_id;
}
out:
if (glock.client_id != fid->clnt->name)
kfree(glock.client_id);
return res;
}
/**
* v9fs_file_lock_dotl - lock a file (or directory)
* @filp: file to be locked
* @cmd: lock command
* @fl: file lock structure
*
*/
static int v9fs_file_lock_dotl(struct file *filp, int cmd, struct file_lock *fl)
{
struct inode *inode = file_inode(filp);
int ret = -ENOLCK;
p9_debug(P9_DEBUG_VFS, "filp: %p cmd:%d lock: %p name: %pD\n",
filp, cmd, fl, filp);
if ((IS_SETLK(cmd) || IS_SETLKW(cmd)) && fl->c.flc_type != F_UNLCK) {
filemap_write_and_wait(inode->i_mapping);
invalidate_mapping_pages(&inode->i_data, 0, -1);
}
if (IS_SETLK(cmd) || IS_SETLKW(cmd))
ret = v9fs_file_do_lock(filp, cmd, fl);
else if (IS_GETLK(cmd))
ret = v9fs_file_getlock(filp, fl);
else
ret = -EINVAL;
return ret;
}
/**
* v9fs_file_flock_dotl - lock a file
* @filp: file to be locked
* @cmd: lock command
* @fl: file lock structure
*
*/
static int v9fs_file_flock_dotl(struct file *filp, int cmd,
struct file_lock *fl)
{
struct inode *inode = file_inode(filp);
int ret = -ENOLCK;
p9_debug(P9_DEBUG_VFS, "filp: %p cmd:%d lock: %p name: %pD\n",
filp, cmd, fl, filp);
if (!(fl->c.flc_flags & FL_FLOCK))
goto out_err;
if ((IS_SETLK(cmd) || IS_SETLKW(cmd)) && fl->c.flc_type != F_UNLCK) {
filemap_write_and_wait(inode->i_mapping);
invalidate_mapping_pages(&inode->i_data, 0, -1);
}
/* Convert flock to posix lock */
fl->c.flc_flags |= FL_POSIX;
fl->c.flc_flags ^= FL_FLOCK;
if (IS_SETLK(cmd) | IS_SETLKW(cmd))
ret = v9fs_file_do_lock(filp, cmd, fl);
else
ret = -EINVAL;
out_err:
return ret;
}
/**
* v9fs_file_read_iter - read from a file
* @iocb: The operation parameters
* @to: The buffer to read into
*
*/
static ssize_t
v9fs_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
{
struct p9_fid *fid = iocb->ki_filp->private_data;
p9_debug(P9_DEBUG_VFS, "fid %d count %zu offset %lld\n",
fid->fid, iov_iter_count(to), iocb->ki_pos);
if (fid->mode & P9L_DIRECT)
return netfs_unbuffered_read_iter(iocb, to);
p9_debug(P9_DEBUG_VFS, "(cached)\n");
return netfs_file_read_iter(iocb, to);
}
/*
* v9fs_file_splice_read - splice-read from a file
* @in: The 9p file to read from
* @ppos: Where to find/update the file position
* @pipe: The pipe to splice into
* @len: The maximum amount of data to splice
* @flags: SPLICE_F_* flags
*/
static ssize_t v9fs_file_splice_read(struct file *in, loff_t *ppos,
struct pipe_inode_info *pipe,
size_t len, unsigned int flags)
{
struct p9_fid *fid = in->private_data;
p9_debug(P9_DEBUG_VFS, "fid %d count %zu offset %lld\n",
fid->fid, len, *ppos);
if (fid->mode & P9L_DIRECT)
return copy_splice_read(in, ppos, pipe, len, flags);
return filemap_splice_read(in, ppos, pipe, len, flags);
}
/**
* v9fs_file_write_iter - write to a file
* @iocb: The operation parameters
* @from: The data to write
*
*/
static ssize_t
v9fs_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
{
struct file *file = iocb->ki_filp;
struct p9_fid *fid = file->private_data;
p9_debug(P9_DEBUG_VFS, "fid %d\n", fid->fid);
if (fid->mode & (P9L_DIRECT | P9L_NOWRITECACHE))
return netfs_unbuffered_write_iter(iocb, from);
p9_debug(P9_DEBUG_CACHE, "(cached)\n");
return netfs_file_write_iter(iocb, from);
}
static int v9fs_file_fsync(struct file *filp, loff_t start, loff_t end,
int datasync)
{
struct p9_fid *fid;
struct inode *inode = filp->f_mapping->host;
struct p9_wstat wstat;
int retval;
retval = file_write_and_wait_range(filp, start, end);
if (retval)
return retval;
inode_lock(inode);
p9_debug(P9_DEBUG_VFS, "filp %p datasync %x\n", filp, datasync);
fid = filp->private_data;
v9fs_blank_wstat(&wstat);
retval = p9_client_wstat(fid, &wstat);
inode_unlock(inode);
return retval;
}
int v9fs_file_fsync_dotl(struct file *filp, loff_t start, loff_t end,
int datasync)
{
struct p9_fid *fid;
struct inode *inode = filp->f_mapping->host;
int retval;
retval = file_write_and_wait_range(filp, start, end);
if (retval)
return retval;
inode_lock(inode);
p9_debug(P9_DEBUG_VFS, "filp %p datasync %x\n", filp, datasync);
fid = filp->private_data;
retval = p9_client_fsync(fid, datasync);
inode_unlock(inode);
return retval;
}
static int
v9fs_file_mmap(struct file *filp, struct vm_area_struct *vma)
{
int retval;
struct inode *inode = file_inode(filp);
struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
p9_debug(P9_DEBUG_MMAP, "filp :%p\n", filp);
if (!(v9ses->cache & CACHE_WRITEBACK)) {
p9_debug(P9_DEBUG_CACHE, "(read-only mmap mode)");
return generic_file_readonly_mmap(filp, vma);
}
retval = generic_file_mmap(filp, vma);
if (!retval)
vma->vm_ops = &v9fs_mmap_file_vm_ops;
return retval;
}
static vm_fault_t
v9fs_vm_page_mkwrite(struct vm_fault *vmf)
{
return netfs_page_mkwrite(vmf, NULL);
}
static void v9fs_mmap_vm_close(struct vm_area_struct *vma)
{
struct inode *inode;
struct writeback_control wbc = {
.nr_to_write = LONG_MAX,
.sync_mode = WB_SYNC_ALL,
.range_start = (loff_t)vma->vm_pgoff * PAGE_SIZE,
/* absolute end, byte at end included */
.range_end = (loff_t)vma->vm_pgoff * PAGE_SIZE +
(vma->vm_end - vma->vm_start - 1),
};
if (!(vma->vm_flags & VM_SHARED))
return;
p9_debug(P9_DEBUG_VFS, "9p VMA close, %p, flushing", vma);
inode = file_inode(vma->vm_file);
filemap_fdatawrite_wbc(inode->i_mapping, &wbc);
}
static const struct vm_operations_struct v9fs_mmap_file_vm_ops = {
.close = v9fs_mmap_vm_close,
.fault = filemap_fault,
.map_pages = filemap_map_pages,
.page_mkwrite = v9fs_vm_page_mkwrite,
};
const struct file_operations v9fs_file_operations = {
.llseek = generic_file_llseek,
.read_iter = v9fs_file_read_iter,
.write_iter = v9fs_file_write_iter,
.open = v9fs_file_open,
.release = v9fs_dir_release,
.lock = v9fs_file_lock,
.mmap = generic_file_readonly_mmap,
.splice_read = v9fs_file_splice_read,
.splice_write = iter_file_splice_write,
.fsync = v9fs_file_fsync,
.setlease = simple_nosetlease,
};
const struct file_operations v9fs_file_operations_dotl = {
.llseek = generic_file_llseek,
.read_iter = v9fs_file_read_iter,
.write_iter = v9fs_file_write_iter,
.open = v9fs_file_open,
.release = v9fs_dir_release,
.lock = v9fs_file_lock_dotl,
.flock = v9fs_file_flock_dotl,
.mmap = v9fs_file_mmap,
.splice_read = v9fs_file_splice_read,
.splice_write = iter_file_splice_write,
.fsync = v9fs_file_fsync_dotl,
.setlease = simple_nosetlease,
};
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