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mirror of https://github.com/edk2-porting/linux-next.git synced 2024-12-25 21:54:06 +08:00
linux-next/fs/ncpfs/file.c
Petr Vandrovec 2e54eb96e2 BKL: Remove BKL from ncpfs
Dozen of changes in ncpfs to provide some locking other than BKL.

In readdir cache unlock and mark complete first page as last operation,
so it can be used for synchronization, as code intended.

When updating dentry name on case insensitive filesystems do at least
some basic locking...

Hold i_mutex when updating inode fields.

Push some ncp_conn_is_valid down to ncp_request.  Connection can become
invalid at any moment, and fewer error code paths to test the better.

Use i_size_{read,write} to modify file size.

Set inode's backing_dev_info as ncpfs has its own special bdi.

In ioctl unbreak ioctls invoked on filesystem mounted 'ro' - tests are
for inode writeable or owner match, but were turned to filesystem
writeable and inode writeable or owner match.  Also collect all permission
checks in single place.

Add some locking, and remove comments saying that it would be cool to
add some locks to the code.

Constify some pointers.

Signed-off-by: Petr Vandrovec <petr@vandrovec.name>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2010-10-04 21:10:52 +02:00

300 lines
6.7 KiB
C

/*
* file.c
*
* Copyright (C) 1995, 1996 by Volker Lendecke
* Modified 1997 Peter Waltenberg, Bill Hawes, David Woodhouse for 2.1 dcache
*
*/
#include <asm/uaccess.h>
#include <asm/system.h>
#include <linux/time.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/fcntl.h>
#include <linux/stat.h>
#include <linux/mm.h>
#include <linux/vmalloc.h>
#include <linux/sched.h>
#include <linux/smp_lock.h>
#include <linux/ncp_fs.h>
#include "ncplib_kernel.h"
static int ncp_fsync(struct file *file, int datasync)
{
return 0;
}
/*
* Open a file with the specified read/write mode.
*/
int ncp_make_open(struct inode *inode, int right)
{
int error;
int access;
error = -EINVAL;
if (!inode) {
printk(KERN_ERR "ncp_make_open: got NULL inode\n");
goto out;
}
DPRINTK("ncp_make_open: opened=%d, volume # %u, dir entry # %u\n",
atomic_read(&NCP_FINFO(inode)->opened),
NCP_FINFO(inode)->volNumber,
NCP_FINFO(inode)->dirEntNum);
error = -EACCES;
mutex_lock(&NCP_FINFO(inode)->open_mutex);
if (!atomic_read(&NCP_FINFO(inode)->opened)) {
struct ncp_entry_info finfo;
int result;
/* tries max. rights */
finfo.access = O_RDWR;
result = ncp_open_create_file_or_subdir(NCP_SERVER(inode),
inode, NULL, OC_MODE_OPEN,
0, AR_READ | AR_WRITE, &finfo);
if (!result)
goto update;
/* RDWR did not succeeded, try readonly or writeonly as requested */
switch (right) {
case O_RDONLY:
finfo.access = O_RDONLY;
result = ncp_open_create_file_or_subdir(NCP_SERVER(inode),
inode, NULL, OC_MODE_OPEN,
0, AR_READ, &finfo);
break;
case O_WRONLY:
finfo.access = O_WRONLY;
result = ncp_open_create_file_or_subdir(NCP_SERVER(inode),
inode, NULL, OC_MODE_OPEN,
0, AR_WRITE, &finfo);
break;
}
if (result) {
PPRINTK("ncp_make_open: failed, result=%d\n", result);
goto out_unlock;
}
/*
* Update the inode information.
*/
update:
ncp_update_inode(inode, &finfo);
atomic_set(&NCP_FINFO(inode)->opened, 1);
}
access = NCP_FINFO(inode)->access;
PPRINTK("ncp_make_open: file open, access=%x\n", access);
if (access == right || access == O_RDWR) {
atomic_inc(&NCP_FINFO(inode)->opened);
error = 0;
}
out_unlock:
mutex_unlock(&NCP_FINFO(inode)->open_mutex);
out:
return error;
}
static ssize_t
ncp_file_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
{
struct dentry *dentry = file->f_path.dentry;
struct inode *inode = dentry->d_inode;
size_t already_read = 0;
off_t pos;
size_t bufsize;
int error;
void* freepage;
size_t freelen;
DPRINTK("ncp_file_read: enter %s/%s\n",
dentry->d_parent->d_name.name, dentry->d_name.name);
pos = *ppos;
if ((ssize_t) count < 0) {
return -EINVAL;
}
if (!count)
return 0;
if (pos > inode->i_sb->s_maxbytes)
return 0;
if (pos + count > inode->i_sb->s_maxbytes) {
count = inode->i_sb->s_maxbytes - pos;
}
error = ncp_make_open(inode, O_RDONLY);
if (error) {
DPRINTK(KERN_ERR "ncp_file_read: open failed, error=%d\n", error);
return error;
}
bufsize = NCP_SERVER(inode)->buffer_size;
error = -EIO;
freelen = ncp_read_bounce_size(bufsize);
freepage = vmalloc(freelen);
if (!freepage)
goto outrel;
error = 0;
/* First read in as much as possible for each bufsize. */
while (already_read < count) {
int read_this_time;
size_t to_read = min_t(unsigned int,
bufsize - (pos % bufsize),
count - already_read);
error = ncp_read_bounce(NCP_SERVER(inode),
NCP_FINFO(inode)->file_handle,
pos, to_read, buf, &read_this_time,
freepage, freelen);
if (error) {
error = -EIO; /* NW errno -> Linux errno */
break;
}
pos += read_this_time;
buf += read_this_time;
already_read += read_this_time;
if (read_this_time != to_read) {
break;
}
}
vfree(freepage);
*ppos = pos;
file_accessed(file);
DPRINTK("ncp_file_read: exit %s/%s\n",
dentry->d_parent->d_name.name, dentry->d_name.name);
outrel:
ncp_inode_close(inode);
return already_read ? already_read : error;
}
static ssize_t
ncp_file_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
{
struct dentry *dentry = file->f_path.dentry;
struct inode *inode = dentry->d_inode;
size_t already_written = 0;
off_t pos;
size_t bufsize;
int errno;
void* bouncebuffer;
DPRINTK("ncp_file_write: enter %s/%s\n",
dentry->d_parent->d_name.name, dentry->d_name.name);
if ((ssize_t) count < 0)
return -EINVAL;
pos = *ppos;
if (file->f_flags & O_APPEND) {
pos = i_size_read(inode);
}
if (pos + count > MAX_NON_LFS && !(file->f_flags&O_LARGEFILE)) {
if (pos >= MAX_NON_LFS) {
return -EFBIG;
}
if (count > MAX_NON_LFS - (u32)pos) {
count = MAX_NON_LFS - (u32)pos;
}
}
if (pos >= inode->i_sb->s_maxbytes) {
if (count || pos > inode->i_sb->s_maxbytes) {
return -EFBIG;
}
}
if (pos + count > inode->i_sb->s_maxbytes) {
count = inode->i_sb->s_maxbytes - pos;
}
if (!count)
return 0;
errno = ncp_make_open(inode, O_WRONLY);
if (errno) {
DPRINTK(KERN_ERR "ncp_file_write: open failed, error=%d\n", errno);
return errno;
}
bufsize = NCP_SERVER(inode)->buffer_size;
already_written = 0;
bouncebuffer = vmalloc(bufsize);
if (!bouncebuffer) {
errno = -EIO; /* -ENOMEM */
goto outrel;
}
while (already_written < count) {
int written_this_time;
size_t to_write = min_t(unsigned int,
bufsize - (pos % bufsize),
count - already_written);
if (copy_from_user(bouncebuffer, buf, to_write)) {
errno = -EFAULT;
break;
}
if (ncp_write_kernel(NCP_SERVER(inode),
NCP_FINFO(inode)->file_handle,
pos, to_write, bouncebuffer, &written_this_time) != 0) {
errno = -EIO;
break;
}
pos += written_this_time;
buf += written_this_time;
already_written += written_this_time;
if (written_this_time != to_write) {
break;
}
}
vfree(bouncebuffer);
file_update_time(file);
*ppos = pos;
if (pos > i_size_read(inode)) {
mutex_lock(&inode->i_mutex);
if (pos > i_size_read(inode))
i_size_write(inode, pos);
mutex_unlock(&inode->i_mutex);
}
DPRINTK("ncp_file_write: exit %s/%s\n",
dentry->d_parent->d_name.name, dentry->d_name.name);
outrel:
ncp_inode_close(inode);
return already_written ? already_written : errno;
}
static int ncp_release(struct inode *inode, struct file *file) {
if (ncp_make_closed(inode)) {
DPRINTK("ncp_release: failed to close\n");
}
return 0;
}
const struct file_operations ncp_file_operations =
{
.llseek = generic_file_llseek,
.read = ncp_file_read,
.write = ncp_file_write,
.unlocked_ioctl = ncp_ioctl,
#ifdef CONFIG_COMPAT
.compat_ioctl = ncp_compat_ioctl,
#endif
.mmap = ncp_mmap,
.release = ncp_release,
.fsync = ncp_fsync,
};
const struct inode_operations ncp_file_inode_operations =
{
.setattr = ncp_notify_change,
};