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![Josef Bacik](/assets/img/avatar_default.png)
Btrfs needs to be able to control how filemap_write_and_wait_range() is called in fsync to make it less of a painful operation, so push down taking i_mutex and the calling of filemap_write_and_wait() down into the ->fsync() handlers. Some file systems can drop taking the i_mutex altogether it seems, like ext3 and ocfs2. For correctness sake I just pushed everything down in all cases to make sure that we keep the current behavior the same for everybody, and then each individual fs maintainer can make up their mind about what to do from there. Thanks, Acked-by: Jan Kara <jack@suse.cz> Signed-off-by: Josef Bacik <josef@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
297 lines
6.7 KiB
C
297 lines
6.7 KiB
C
/*
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* file.c
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*
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* Copyright (C) 1995, 1996 by Volker Lendecke
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* Modified 1997 Peter Waltenberg, Bill Hawes, David Woodhouse for 2.1 dcache
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*
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*/
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#include <asm/uaccess.h>
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#include <asm/system.h>
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#include <linux/time.h>
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#include <linux/kernel.h>
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#include <linux/errno.h>
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#include <linux/fcntl.h>
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#include <linux/stat.h>
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#include <linux/mm.h>
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#include <linux/vmalloc.h>
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#include <linux/sched.h>
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#include "ncp_fs.h"
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static int ncp_fsync(struct file *file, loff_t start, loff_t end, int datasync)
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{
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return filemap_write_and_wait_range(file->f_mapping, start, end);
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}
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/*
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* Open a file with the specified read/write mode.
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*/
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int ncp_make_open(struct inode *inode, int right)
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{
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int error;
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int access;
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error = -EINVAL;
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if (!inode) {
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printk(KERN_ERR "ncp_make_open: got NULL inode\n");
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goto out;
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}
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DPRINTK("ncp_make_open: opened=%d, volume # %u, dir entry # %u\n",
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atomic_read(&NCP_FINFO(inode)->opened),
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NCP_FINFO(inode)->volNumber,
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NCP_FINFO(inode)->dirEntNum);
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error = -EACCES;
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mutex_lock(&NCP_FINFO(inode)->open_mutex);
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if (!atomic_read(&NCP_FINFO(inode)->opened)) {
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struct ncp_entry_info finfo;
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int result;
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/* tries max. rights */
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finfo.access = O_RDWR;
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result = ncp_open_create_file_or_subdir(NCP_SERVER(inode),
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inode, NULL, OC_MODE_OPEN,
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0, AR_READ | AR_WRITE, &finfo);
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if (!result)
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goto update;
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/* RDWR did not succeeded, try readonly or writeonly as requested */
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switch (right) {
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case O_RDONLY:
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finfo.access = O_RDONLY;
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result = ncp_open_create_file_or_subdir(NCP_SERVER(inode),
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inode, NULL, OC_MODE_OPEN,
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0, AR_READ, &finfo);
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break;
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case O_WRONLY:
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finfo.access = O_WRONLY;
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result = ncp_open_create_file_or_subdir(NCP_SERVER(inode),
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inode, NULL, OC_MODE_OPEN,
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0, AR_WRITE, &finfo);
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break;
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}
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if (result) {
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PPRINTK("ncp_make_open: failed, result=%d\n", result);
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goto out_unlock;
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}
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/*
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* Update the inode information.
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*/
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update:
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ncp_update_inode(inode, &finfo);
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atomic_set(&NCP_FINFO(inode)->opened, 1);
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}
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access = NCP_FINFO(inode)->access;
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PPRINTK("ncp_make_open: file open, access=%x\n", access);
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if (access == right || access == O_RDWR) {
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atomic_inc(&NCP_FINFO(inode)->opened);
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error = 0;
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}
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out_unlock:
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mutex_unlock(&NCP_FINFO(inode)->open_mutex);
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out:
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return error;
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}
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static ssize_t
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ncp_file_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
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{
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struct dentry *dentry = file->f_path.dentry;
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struct inode *inode = dentry->d_inode;
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size_t already_read = 0;
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off_t pos;
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size_t bufsize;
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int error;
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void* freepage;
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size_t freelen;
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DPRINTK("ncp_file_read: enter %s/%s\n",
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dentry->d_parent->d_name.name, dentry->d_name.name);
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pos = *ppos;
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if ((ssize_t) count < 0) {
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return -EINVAL;
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}
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if (!count)
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return 0;
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if (pos > inode->i_sb->s_maxbytes)
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return 0;
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if (pos + count > inode->i_sb->s_maxbytes) {
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count = inode->i_sb->s_maxbytes - pos;
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}
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error = ncp_make_open(inode, O_RDONLY);
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if (error) {
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DPRINTK(KERN_ERR "ncp_file_read: open failed, error=%d\n", error);
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return error;
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}
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bufsize = NCP_SERVER(inode)->buffer_size;
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error = -EIO;
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freelen = ncp_read_bounce_size(bufsize);
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freepage = vmalloc(freelen);
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if (!freepage)
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goto outrel;
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error = 0;
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/* First read in as much as possible for each bufsize. */
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while (already_read < count) {
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int read_this_time;
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size_t to_read = min_t(unsigned int,
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bufsize - (pos % bufsize),
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count - already_read);
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error = ncp_read_bounce(NCP_SERVER(inode),
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NCP_FINFO(inode)->file_handle,
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pos, to_read, buf, &read_this_time,
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freepage, freelen);
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if (error) {
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error = -EIO; /* NW errno -> Linux errno */
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break;
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}
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pos += read_this_time;
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buf += read_this_time;
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already_read += read_this_time;
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if (read_this_time != to_read) {
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break;
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}
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}
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vfree(freepage);
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*ppos = pos;
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file_accessed(file);
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DPRINTK("ncp_file_read: exit %s/%s\n",
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dentry->d_parent->d_name.name, dentry->d_name.name);
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outrel:
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ncp_inode_close(inode);
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return already_read ? already_read : error;
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}
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static ssize_t
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ncp_file_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
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{
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struct dentry *dentry = file->f_path.dentry;
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struct inode *inode = dentry->d_inode;
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size_t already_written = 0;
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off_t pos;
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size_t bufsize;
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int errno;
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void* bouncebuffer;
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DPRINTK("ncp_file_write: enter %s/%s\n",
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dentry->d_parent->d_name.name, dentry->d_name.name);
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if ((ssize_t) count < 0)
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return -EINVAL;
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pos = *ppos;
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if (file->f_flags & O_APPEND) {
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pos = i_size_read(inode);
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}
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if (pos + count > MAX_NON_LFS && !(file->f_flags&O_LARGEFILE)) {
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if (pos >= MAX_NON_LFS) {
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return -EFBIG;
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}
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if (count > MAX_NON_LFS - (u32)pos) {
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count = MAX_NON_LFS - (u32)pos;
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}
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}
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if (pos >= inode->i_sb->s_maxbytes) {
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if (count || pos > inode->i_sb->s_maxbytes) {
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return -EFBIG;
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}
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}
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if (pos + count > inode->i_sb->s_maxbytes) {
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count = inode->i_sb->s_maxbytes - pos;
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}
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if (!count)
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return 0;
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errno = ncp_make_open(inode, O_WRONLY);
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if (errno) {
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DPRINTK(KERN_ERR "ncp_file_write: open failed, error=%d\n", errno);
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return errno;
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}
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bufsize = NCP_SERVER(inode)->buffer_size;
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already_written = 0;
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bouncebuffer = vmalloc(bufsize);
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if (!bouncebuffer) {
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errno = -EIO; /* -ENOMEM */
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goto outrel;
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}
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while (already_written < count) {
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int written_this_time;
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size_t to_write = min_t(unsigned int,
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bufsize - (pos % bufsize),
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count - already_written);
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if (copy_from_user(bouncebuffer, buf, to_write)) {
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errno = -EFAULT;
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break;
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}
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if (ncp_write_kernel(NCP_SERVER(inode),
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NCP_FINFO(inode)->file_handle,
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pos, to_write, bouncebuffer, &written_this_time) != 0) {
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errno = -EIO;
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break;
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}
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pos += written_this_time;
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buf += written_this_time;
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already_written += written_this_time;
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if (written_this_time != to_write) {
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break;
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}
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}
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vfree(bouncebuffer);
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file_update_time(file);
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*ppos = pos;
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if (pos > i_size_read(inode)) {
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mutex_lock(&inode->i_mutex);
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if (pos > i_size_read(inode))
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i_size_write(inode, pos);
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mutex_unlock(&inode->i_mutex);
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}
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DPRINTK("ncp_file_write: exit %s/%s\n",
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dentry->d_parent->d_name.name, dentry->d_name.name);
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outrel:
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ncp_inode_close(inode);
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return already_written ? already_written : errno;
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}
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static int ncp_release(struct inode *inode, struct file *file) {
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if (ncp_make_closed(inode)) {
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DPRINTK("ncp_release: failed to close\n");
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}
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return 0;
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}
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const struct file_operations ncp_file_operations =
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{
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.llseek = generic_file_llseek,
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.read = ncp_file_read,
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.write = ncp_file_write,
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.unlocked_ioctl = ncp_ioctl,
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#ifdef CONFIG_COMPAT
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.compat_ioctl = ncp_compat_ioctl,
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#endif
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.mmap = ncp_mmap,
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.release = ncp_release,
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.fsync = ncp_fsync,
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};
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const struct inode_operations ncp_file_inode_operations =
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{
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.setattr = ncp_notify_change,
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};
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