/*
* 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/time.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/fcntl.h>
#include <linux/stat.h>
#include <linux/nfs_fs.h>
#include <linux/nfs_mount.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/pagemap.h>
#include <linux/smp_lock.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#include "delegation.h"
#include "iostat.h"
#define NFSDBG_FACILITY NFSDBG_FILE
static int nfs_file_open(struct inode *, struct file *);
static int nfs_file_release(struct inode *, struct file *);
static loff_t nfs_file_llseek(struct file *file, loff_t offset, int origin);
static int nfs_file_mmap(struct file *, struct vm_area_struct *);
static ssize_t nfs_file_sendfile(struct file *, loff_t *, size_t, read_actor_t, void *);
static ssize_t nfs_file_read(struct kiocb *, const struct iovec *iov,
unsigned long nr_segs, loff_t pos);
static ssize_t nfs_file_write(struct kiocb *, const struct iovec *iov,
unsigned long nr_segs, loff_t pos);
static int nfs_file_flush(struct file *, fl_owner_t id);
static int nfs_fsync(struct file *, struct dentry *dentry, int datasync);
static int nfs_check_flags(int flags);
static int nfs_lock(struct file *filp, int cmd, struct file_lock *fl);
static int nfs_flock(struct file *filp, int cmd, struct file_lock *fl);
const struct file_operations nfs_file_operations = {
.llseek = nfs_file_llseek,
.read = do_sync_read,
.write = do_sync_write,
.aio_read = nfs_file_read,
.aio_write = nfs_file_write,
.mmap = nfs_file_mmap,
.open = nfs_file_open,
.flush = nfs_file_flush,
.release = nfs_file_release,
.fsync = nfs_fsync,
.lock = nfs_lock,
.flock = nfs_flock,
.sendfile = nfs_file_sendfile,
.check_flags = nfs_check_flags,
};
struct inode_operations nfs_file_inode_operations = {
.permission = nfs_permission,
.getattr = nfs_getattr,
.setattr = nfs_setattr,
};
#ifdef CONFIG_NFS_V3
struct inode_operations nfs3_file_inode_operations = {
.permission = nfs_permission,
.getattr = nfs_getattr,
.setattr = nfs_setattr,
.listxattr = nfs3_listxattr,
.getxattr = nfs3_getxattr,
.setxattr = nfs3_setxattr,
.removexattr = nfs3_removexattr,
};
#endif /* CONFIG_NFS_v3 */
/* Hack for future NFS swap support */
#ifndef IS_SWAPFILE
# define IS_SWAPFILE(inode) (0)
#endif
static int nfs_check_flags(int flags)
{
if ((flags & (O_APPEND | O_DIRECT)) == (O_APPEND | O_DIRECT))
return -EINVAL;
return 0;
}
/*
* Open file
*/
static int
nfs_file_open(struct inode *inode, struct file *filp)
{
int res;
res = nfs_check_flags(filp->f_flags);
if (res)
return res;
nfs_inc_stats(inode, NFSIOS_VFSOPEN);
lock_kernel();
res = NFS_PROTO(inode)->file_open(inode, filp);
unlock_kernel();
return res;
}
static int
nfs_file_release(struct inode *inode, struct file *filp)
{
/* Ensure that dirty pages are flushed out with the right creds */
if (filp->f_mode & FMODE_WRITE)
filemap_fdatawrite(filp->f_mapping);
nfs_inc_stats(inode, NFSIOS_VFSRELEASE);
return NFS_PROTO(inode)->file_release(inode, filp);
}
/**
* nfs_revalidate_size - Revalidate the file size
* @inode - pointer to inode struct
* @file - pointer to struct file
*
* Revalidates the file length. This is basically a wrapper around
* nfs_revalidate_inode() that takes into account the fact that we may
* have cached writes (in which case we don't care about the server's
* idea of what the file length is), or O_DIRECT (in which case we
* shouldn't trust the cache).
*/
static int nfs_revalidate_file_size(struct inode *inode, struct file *filp)
{
struct nfs_server *server = NFS_SERVER(inode);
struct nfs_inode *nfsi = NFS_I(inode);
if (server->flags & NFS_MOUNT_NOAC)
goto force_reval;
if (filp->f_flags & O_DIRECT)
goto force_reval;
if (nfsi->npages != 0)
return 0;
if (!(nfsi->cache_validity & NFS_INO_REVAL_PAGECACHE) && !nfs_attribute_timeout(inode))
return 0;
force_reval:
return __nfs_revalidate_inode(server, inode);
}
static loff_t nfs_file_llseek(struct file *filp, loff_t offset, int origin)
{
/* origin == SEEK_END => we must revalidate the cached file length */
if (origin == SEEK_END) {
struct inode *inode = filp->f_mapping->host;
int retval = nfs_revalidate_file_size(inode, filp);
if (retval < 0)
return (loff_t)retval;
}
return remote_llseek(filp, offset, origin);
}
/*
* Flush all dirty pages, and check for write errors.
*
*/
static int
nfs_file_flush(struct file *file, fl_owner_t id)
{
struct nfs_open_context *ctx = (struct nfs_open_context *)file->private_data;
struct inode *inode = file->f_dentry->d_inode;
int status;
dfprintk(VFS, "nfs: flush(%s/%ld)\n", inode->i_sb->s_id, inode->i_ino);
if ((file->f_mode & FMODE_WRITE) == 0)
return 0;
nfs_inc_stats(inode, NFSIOS_VFSFLUSH);
lock_kernel();
/* Ensure that data+attribute caches are up to date after close() */
status = nfs_wb_all(inode);
if (!status) {
status = ctx->error;
ctx->error = 0;
if (!status)
nfs_revalidate_inode(NFS_SERVER(inode), inode);
}
unlock_kernel();
return status;
}
static ssize_t
nfs_file_read(struct kiocb *iocb, const struct iovec *iov,
unsigned long nr_segs, loff_t pos)
{
struct dentry * dentry = iocb->ki_filp->f_dentry;
struct inode * inode = dentry->d_inode;
ssize_t result;
size_t count = iov_length(iov, nr_segs);
#ifdef CONFIG_NFS_DIRECTIO
if (iocb->ki_filp->f_flags & O_DIRECT)
return nfs_file_direct_read(iocb, iov, nr_segs, pos);
#endif
dfprintk(VFS, "nfs: read(%s/%s, %lu@%lu)\n",
dentry->d_parent->d_name.name, dentry->d_name.name,
(unsigned long) count, (unsigned long) pos);
result = nfs_revalidate_mapping(inode, iocb->ki_filp->f_mapping);
nfs_add_stats(inode, NFSIOS_NORMALREADBYTES, count);
if (!result)
result = generic_file_aio_read(iocb, iov, nr_segs, pos);
return result;
}
static ssize_t
nfs_file_sendfile(struct file *filp, loff_t *ppos, size_t count,
read_actor_t actor, void *target)
{
struct dentry *dentry = filp->f_dentry;
struct inode *inode = dentry->d_inode;
ssize_t res;
dfprintk(VFS, "nfs: sendfile(%s/%s, %lu@%Lu)\n",
dentry->d_parent->d_name.name, dentry->d_name.name,
(unsigned long) count, (unsigned long long) *ppos);
res = nfs_revalidate_mapping(inode, filp->f_mapping);
if (!res)
res = generic_file_sendfile(filp, ppos, count, actor, target);
return res;
}
static int
nfs_file_mmap(struct file * file, struct vm_area_struct * vma)
{
struct dentry *dentry = file->f_dentry;
struct inode *inode = dentry->d_inode;
int status;
dfprintk(VFS, "nfs: mmap(%s/%s)\n",
dentry->d_parent->d_name.name, dentry->d_name.name);
status = nfs_revalidate_mapping(inode, file->f_mapping);
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, int datasync)
{
struct nfs_open_context *ctx = (struct nfs_open_context *)file->private_data;
struct inode *inode = dentry->d_inode;
int status;
dfprintk(VFS, "nfs: fsync(%s/%ld)\n", inode->i_sb->s_id, inode->i_ino);
nfs_inc_stats(inode, NFSIOS_VFSFSYNC);
lock_kernel();
status = nfs_wb_all(inode);
if (!status) {
status = ctx->error;
ctx->error = 0;
}
unlock_kernel();
return status;
}
/*
* This does the "real" work of the write. The generic routine has
* allocated the page, locked it, done all the page alignment stuff
* calculations etc. Now we should just copy the data from user
* space and write it back to the real medium..
*
* If the writer ends up delaying the write, the writer needs to
* increment the page use counts until he is done with the page.
*/
static int nfs_prepare_write(struct file *file, struct page *page, unsigned offset, unsigned to)
{
return nfs_flush_incompatible(file, page);
}
static int nfs_commit_write(struct file *file, struct page *page, unsigned offset, unsigned to)
{
long status;
lock_kernel();
status = nfs_updatepage(file, page, offset, to-offset);
unlock_kernel();
return status;
}
static void nfs_invalidate_page(struct page *page, unsigned long offset)
{
loff_t range_start, range_end;
if (offset != 0)
return;
/* Cancel any unstarted writes on this page */
range_start = page_offset(page);
range_end = range_start + (loff_t)(PAGE_CACHE_SIZE - 1);
nfs_sync_mapping_range(page->mapping, range_start, range_end, FLUSH_INVALIDATE);
}
static int nfs_release_page(struct page *page, gfp_t gfp)
{
if (gfp & __GFP_FS)
return !nfs_wb_page(page->mapping->host, page);
else
/*
* Avoid deadlock on nfs_wait_on_request().
*/
return 0;
}
const struct address_space_operations nfs_file_aops = {
.readpage = nfs_readpage,
.readpages = nfs_readpages,
.set_page_dirty = __set_page_dirty_nobuffers,
.writepage = nfs_writepage,
.writepages = nfs_writepages,
.prepare_write = nfs_prepare_write,
.commit_write = nfs_commit_write,
.invalidatepage = nfs_invalidate_page,
.releasepage = nfs_release_page,
#ifdef CONFIG_NFS_DIRECTIO
.direct_IO = nfs_direct_IO,
#endif
};
static ssize_t nfs_file_write(struct kiocb *iocb, const struct iovec *iov,
unsigned long nr_segs, loff_t pos)
{
struct dentry * dentry = iocb->ki_filp->f_dentry;
struct inode * inode = dentry->d_inode;
ssize_t result;
size_t count = iov_length(iov, nr_segs);
#ifdef CONFIG_NFS_DIRECTIO
if (iocb->ki_filp->f_flags & O_DIRECT)
return nfs_file_direct_write(iocb, iov, nr_segs, pos);
#endif
dfprintk(VFS, "nfs: write(%s/%s(%ld), %lu@%Ld)\n",
dentry->d_parent->d_name.name, dentry->d_name.name,
inode->i_ino, (unsigned long) count, (long long) pos);
result = -EBUSY;
if (IS_SWAPFILE(inode))
goto out_swapfile;
/*
* O_APPEND implies that we must revalidate the file length.
*/
if (iocb->ki_filp->f_flags & O_APPEND) {
result = nfs_revalidate_file_size(inode, iocb->ki_filp);
if (result)
goto out;
}
result = count;
if (!count)
goto out;
nfs_add_stats(inode, NFSIOS_NORMALWRITTENBYTES, count);
result = generic_file_aio_write(iocb, iov, nr_segs, pos);
out:
return result;
out_swapfile:
printk(KERN_INFO "NFS: attempt to write to active swap file!\n");
goto out;
}
static int do_getlk(struct file *filp, int cmd, struct file_lock *fl)
{
struct file_lock cfl;
struct inode *inode = filp->f_mapping->host;
int status = 0;
lock_kernel();
/* Try local locking first */
if (posix_test_lock(filp, fl, &cfl)) {
fl->fl_start = cfl.fl_start;
fl->fl_end = cfl.fl_end;
fl->fl_type = cfl.fl_type;
fl->fl_pid = cfl.fl_pid;
goto out;
}
if (nfs_have_delegation(inode, FMODE_READ))
goto out_noconflict;
if (NFS_SERVER(inode)->flags & NFS_MOUNT_NONLM)
goto out_noconflict;
status = NFS_PROTO(inode)->lock(filp, cmd, fl);
out:
unlock_kernel();
return status;
out_noconflict:
fl->fl_type = F_UNLCK;
goto out;
}
static int do_vfs_lock(struct file *file, struct file_lock *fl)
{
int res = 0;
switch (fl->fl_flags & (FL_POSIX|FL_FLOCK)) {
case FL_POSIX:
res = posix_lock_file_wait(file, fl);
break;
case FL_FLOCK:
res = flock_lock_file_wait(file, fl);
break;
default:
BUG();
}
if (res < 0)
printk(KERN_WARNING "%s: VFS is out of sync with lock manager!\n",
__FUNCTION__);
return res;
}
static int do_unlk(struct file *filp, int cmd, struct file_lock *fl)
{
struct inode *inode = filp->f_mapping->host;
int status;
/*
* Flush all pending writes before doing anything
* with locks..
*/
nfs_sync_mapping(filp->f_mapping);
/* NOTE: special case
* If we're signalled while cleaning up locks on process exit, we
* still need to complete the unlock.
*/
lock_kernel();
/* Use local locking if mounted with "-onolock" */
if (!(NFS_SERVER(inode)->flags & NFS_MOUNT_NONLM))
status = NFS_PROTO(inode)->lock(filp, cmd, fl);
else
status = do_vfs_lock(filp, fl);
unlock_kernel();
return status;
}
static int do_setlk(struct file *filp, int cmd, struct file_lock *fl)
{
struct inode *inode = filp->f_mapping->host;
int status;
/*
* Flush all pending writes before doing anything
* with locks..
*/
status = nfs_sync_mapping(filp->f_mapping);
if (status != 0)
goto out;
lock_kernel();
/* Use local locking if mounted with "-onolock" */
if (!(NFS_SERVER(inode)->flags & NFS_MOUNT_NONLM)) {
status = NFS_PROTO(inode)->lock(filp, cmd, fl);
/* If we were signalled we still need to ensure that
* we clean up any state on the server. We therefore
* record the lock call as having succeeded in order to
* ensure that locks_remove_posix() cleans it out when
* the process exits.
*/
if (status == -EINTR || status == -ERESTARTSYS)
do_vfs_lock(filp, fl);
} else
status = do_vfs_lock(filp, fl);
unlock_kernel();
if (status < 0)
goto out;
/*
* Make sure we clear the cache whenever we try to get the lock.
* This makes locking act as a cache coherency point.
*/
nfs_sync_mapping(filp->f_mapping);
nfs_zap_caches(inode);
out:
return status;
}
/*
* Lock a (portion of) a file
*/
static int nfs_lock(struct file *filp, int cmd, struct file_lock *fl)
{
struct inode * inode = filp->f_mapping->host;
dprintk("NFS: nfs_lock(f=%s/%ld, t=%x, fl=%x, r=%Ld:%Ld)\n",
inode->i_sb->s_id, inode->i_ino,
fl->fl_type, fl->fl_flags,
(long long)fl->fl_start, (long long)fl->fl_end);
nfs_inc_stats(inode, NFSIOS_VFSLOCK);
/* No mandatory locks over NFS */
if ((inode->i_mode & (S_ISGID | S_IXGRP)) == S_ISGID &&
fl->fl_type != F_UNLCK)
return -ENOLCK;
if (IS_GETLK(cmd))
return do_getlk(filp, cmd, fl);
if (fl->fl_type == F_UNLCK)
return do_unlk(filp, cmd, fl);
return do_setlk(filp, cmd, fl);
}
/*
* Lock a (portion of) a file
*/
static int nfs_flock(struct file *filp, int cmd, struct file_lock *fl)
{
dprintk("NFS: nfs_flock(f=%s/%ld, t=%x, fl=%x)\n",
filp->f_dentry->d_inode->i_sb->s_id,
filp->f_dentry->d_inode->i_ino,
fl->fl_type, fl->fl_flags);
/*
* 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_flags & FL_FLOCK))
return -ENOLCK;
/* We're simulating flock() locks using posix locks on the server */
fl->fl_owner = (fl_owner_t)filp;
fl->fl_start = 0;
fl->fl_end = OFFSET_MAX;
if (fl->fl_type == F_UNLCK)
return do_unlk(filp, cmd, fl);
return do_setlk(filp, cmd, fl);
}
