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* linux/fs/nfs/file.c
*
* Copyright (C) 1992 Rick Sladkey
*
* Changes Copyright (C) 1994 by Florian La Roche
* - Do not copy data too often around in the kernel.
* - In nfs_file_read the return value of kmalloc wasn't checked.
* - Put in a better version of read look-ahead buffering. Original idea
* and implementation by Wai S Kok elekokws@ee.nus.sg.
*
* Expire cache on write to a file by Wai S Kok (Oct 1994).
*
* Total rewrite of read side for new NFS buffer cache.. Linus.
*
* nfs regular file handling functions
*/
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/fcntl.h>
#include <linux/stat.h>
#include <linux/nfs_fs.h>
#include <linux/mm.h>
#include <linux/malloc.h>
#include <linux/pagemap.h>
#include <linux/lockd/bind.h>
#include <asm/segment.h>
#include <asm/system.h>
#define NFSDBG_FACILITY NFSDBG_FILE
static int nfs_file_mmap(struct file *, struct vm_area_struct *);
static ssize_t nfs_file_read(struct file *, char *, size_t, loff_t *);
static ssize_t nfs_file_write(struct file *, const char *, size_t, loff_t *);
static int nfs_file_flush(struct file *);
static int nfs_fsync(struct file *, struct dentry *dentry);
static struct file_operations nfs_file_operations = {
NULL, /* lseek - default */
nfs_file_read, /* read */
nfs_file_write, /* write */
NULL, /* readdir - bad */
NULL, /* select - default */
NULL, /* ioctl - default */
nfs_file_mmap, /* mmap */
nfs_open, /* open */
nfs_file_flush, /* flush */
nfs_release, /* release */
nfs_fsync, /* fsync */
NULL, /* fasync */
NULL, /* check_media_change */
NULL, /* revalidate */
nfs_lock, /* lock */
};
struct inode_operations nfs_file_inode_operations = {
&nfs_file_operations, /* default file operations */
NULL, /* create */
NULL, /* lookup */
NULL, /* link */
NULL, /* unlink */
NULL, /* symlink */
NULL, /* mkdir */
NULL, /* rmdir */
NULL, /* mknod */
NULL, /* rename */
NULL, /* readlink */
NULL, /* follow_link */
nfs_readpage, /* readpage */
nfs_writepage, /* writepage */
NULL, /* bmap */
NULL, /* truncate */
NULL, /* permission */
NULL, /* smap */
nfs_updatepage, /* updatepage */
nfs_revalidate, /* revalidate */
};
/* Hack for future NFS swap support */
#ifndef IS_SWAPFILE
# define IS_SWAPFILE(inode) (0)
#endif
/*
* Flush all dirty pages, and check for write errors.
*
*/
static int
nfs_file_flush(struct file *file)
{
struct inode *inode = file->f_dentry->d_inode;
int status;
dfprintk(VFS, "nfs: flush(%x/%ld)\n", inode->i_dev, inode->i_ino);
status = nfs_wb_file(inode, file);
if (!status) {
status = file->f_error;
file->f_error = 0;
}
return status;
}
static ssize_t
nfs_file_read(struct file * file, char * buf, size_t count, loff_t *ppos)
{
struct dentry * dentry = file->f_dentry;
ssize_t result;
dfprintk(VFS, "nfs: read(%s/%s, %lu@%lu)\n",
dentry->d_parent->d_name.name, dentry->d_name.name,
(unsigned long) count, (unsigned long) *ppos);
result = nfs_revalidate_inode(NFS_DSERVER(dentry), dentry);
if (!result)
result = generic_file_read(file, buf, count, ppos);
return result;
}
static int
nfs_file_mmap(struct file * file, struct vm_area_struct * vma)
{
struct dentry *dentry = file->f_dentry;
int status;
dfprintk(VFS, "nfs: mmap(%s/%s)\n",
dentry->d_parent->d_name.name, dentry->d_name.name);
status = nfs_revalidate_inode(NFS_DSERVER(dentry), dentry);
if (!status)
status = generic_file_mmap(file, vma);
return status;
}
/*
* Flush any dirty pages for this process, and check for write errors.
* The return status from this call provides a reliable indication of
* whether any write errors occurred for this process.
*/
static int
nfs_fsync(struct file *file, struct dentry *dentry)
{
struct inode *inode = dentry->d_inode;
int status;
dfprintk(VFS, "nfs: fsync(%x/%ld)\n", inode->i_dev, inode->i_ino);
status = nfs_wb_file(inode, file);
if (!status) {
status = file->f_error;
file->f_error = 0;
}
return status;
}
/*
* Write to a file (through the page cache).
*/
static ssize_t
nfs_file_write(struct file *file, const char *buf, size_t count, loff_t *ppos)
{
struct dentry * dentry = file->f_dentry;
struct inode * inode = dentry->d_inode;
ssize_t result;
dfprintk(VFS, "nfs: write(%s/%s(%ld), %lu@%lu)\n",
dentry->d_parent->d_name.name, dentry->d_name.name,
inode->i_ino, (unsigned long) count, (unsigned long) *ppos);
result = -EBUSY;
if (IS_SWAPFILE(inode))
goto out_swapfile;
result = nfs_revalidate_inode(NFS_DSERVER(dentry), dentry);
if (result)
goto out;
result = count;
if (!count)
goto out;
result = generic_file_write(file, buf, count, ppos);
out:
return result;
out_swapfile:
printk(KERN_INFO "NFS: attempt to write to active swap file!\n");
goto out;
}
/*
* Lock a (portion of) a file
*/
int
nfs_lock(struct file *filp, int cmd, struct file_lock *fl)
{
struct inode * inode = filp->f_dentry->d_inode;
int status;
dprintk("NFS: nfs_lock(f=%4x/%ld, t=%x, fl=%x, r=%ld:%ld)\n",
inode->i_dev, inode->i_ino,
fl->fl_type, fl->fl_flags,
fl->fl_start, fl->fl_end);
if (!inode)
return -EINVAL;
/* No mandatory locks over NFS */
if ((inode->i_mode & (S_ISGID | S_IXGRP)) == S_ISGID)
return -ENOLCK;
/* Fake OK code if mounted without NLM support */
if (NFS_SERVER(inode)->flags & NFS_MOUNT_NONLM)
return 0;
/*
* No BSD flocks over NFS allowed.
* Note: we could try to fake a POSIX lock request here by
* using ((u32) filp | 0x80000000) or some such as the pid.
* Not sure whether that would be unique, though, or whether
* that would break in other places.
*/
if (!fl->fl_owner || (fl->fl_flags & (FL_POSIX|FL_BROKEN)) != FL_POSIX)
return -ENOLCK;
/*
* Flush all pending writes before doing anything
* with locks..
*/
status = nfs_wb_all(inode);
if (status < 0)
return status;
if ((status = nlmclnt_proc(inode, cmd, fl)) < 0)
return status;
/*
* Make sure we re-validate anything we've got cached.
* This makes locking act as a cache coherency point.
*/
NFS_CACHEINV(inode);
return 0;
}
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