![Eric Van Hensbergen](/assets/img/avatar_default.png)
Loose mode in 9p utilizes the page cache without respecting coherency with the server. Any writes previously invaldiated the entire mapping for a file. This patch softens the behavior to only invalidate the region of the actual write. Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
199 lines
4.7 KiB
C
199 lines
4.7 KiB
C
/*
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* linux/fs/9p/vfs_file.c
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*
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* This file contians vfs file ops for 9P2000.
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*
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* Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
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* Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2
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* as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to:
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* Free Software Foundation
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* 51 Franklin Street, Fifth Floor
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* Boston, MA 02111-1301 USA
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*
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*/
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#include <linux/module.h>
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#include <linux/errno.h>
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#include <linux/fs.h>
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#include <linux/sched.h>
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#include <linux/file.h>
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#include <linux/stat.h>
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#include <linux/string.h>
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#include <linux/inet.h>
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#include <linux/list.h>
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#include <asm/uaccess.h>
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#include <linux/idr.h>
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#include <net/9p/9p.h>
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#include <net/9p/client.h>
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#include "v9fs.h"
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#include "v9fs_vfs.h"
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#include "fid.h"
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static const struct file_operations v9fs_cached_file_operations;
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/**
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* v9fs_file_open - open a file (or directory)
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* @inode: inode to be opened
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* @file: file being opened
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*
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*/
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int v9fs_file_open(struct inode *inode, struct file *file)
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{
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int err;
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struct v9fs_session_info *v9ses;
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struct p9_fid *fid;
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int omode;
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P9_DPRINTK(P9_DEBUG_VFS, "inode: %p file: %p \n", inode, file);
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v9ses = v9fs_inode2v9ses(inode);
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omode = v9fs_uflags2omode(file->f_flags);
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fid = file->private_data;
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if (!fid) {
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fid = v9fs_fid_clone(file->f_path.dentry);
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if (IS_ERR(fid))
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return PTR_ERR(fid);
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err = p9_client_open(fid, omode);
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if (err < 0) {
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p9_client_clunk(fid);
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return err;
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}
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if (omode & P9_OTRUNC) {
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inode->i_size = 0;
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inode->i_blocks = 0;
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}
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}
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file->private_data = fid;
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if ((fid->qid.version) && (v9ses->cache)) {
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P9_DPRINTK(P9_DEBUG_VFS, "cached");
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/* enable cached file options */
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if(file->f_op == &v9fs_file_operations)
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file->f_op = &v9fs_cached_file_operations;
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}
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return 0;
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}
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/**
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* v9fs_file_lock - lock a file (or directory)
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* @inode: inode to be opened
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* @file: file being opened
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*
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* XXX - this looks like a local only lock, we should extend into 9P
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* by using open exclusive
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*/
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static int v9fs_file_lock(struct file *filp, int cmd, struct file_lock *fl)
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{
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int res = 0;
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struct inode *inode = filp->f_path.dentry->d_inode;
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P9_DPRINTK(P9_DEBUG_VFS, "filp: %p lock: %p\n", filp, fl);
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/* No mandatory locks */
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if (__mandatory_lock(inode))
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return -ENOLCK;
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if ((IS_SETLK(cmd) || IS_SETLKW(cmd)) && fl->fl_type != F_UNLCK) {
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filemap_write_and_wait(inode->i_mapping);
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invalidate_mapping_pages(&inode->i_data, 0, -1);
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}
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return res;
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}
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/**
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* v9fs_file_read - read from a file
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* @filep: file pointer to read
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* @data: data buffer to read data into
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* @count: size of buffer
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* @offset: offset at which to read data
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*
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*/
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static ssize_t
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v9fs_file_read(struct file *filp, char __user * data, size_t count,
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loff_t * offset)
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{
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int ret;
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struct p9_fid *fid;
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P9_DPRINTK(P9_DEBUG_VFS, "\n");
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fid = filp->private_data;
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ret = p9_client_uread(fid, data, *offset, count);
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if (ret > 0)
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*offset += ret;
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return ret;
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}
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/**
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* v9fs_file_write - write to a file
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* @filep: file pointer to write
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* @data: data buffer to write data from
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* @count: size of buffer
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* @offset: offset at which to write data
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*
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*/
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static ssize_t
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v9fs_file_write(struct file *filp, const char __user * data,
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size_t count, loff_t * offset)
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{
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int ret;
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struct p9_fid *fid;
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struct inode *inode = filp->f_path.dentry->d_inode;
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P9_DPRINTK(P9_DEBUG_VFS, "data %p count %d offset %x\n", data,
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(int)count, (int)*offset);
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fid = filp->private_data;
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ret = p9_client_uwrite(fid, data, *offset, count);
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if (ret > 0) {
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invalidate_inode_pages2_range(inode->i_mapping, *offset,
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*offset+ret);
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*offset += ret;
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}
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if (*offset > inode->i_size) {
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inode->i_size = *offset;
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inode->i_blocks = (inode->i_size + 512 - 1) >> 9;
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}
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return ret;
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}
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static const struct file_operations v9fs_cached_file_operations = {
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.llseek = generic_file_llseek,
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.read = do_sync_read,
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.aio_read = generic_file_aio_read,
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.write = v9fs_file_write,
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.open = v9fs_file_open,
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.release = v9fs_dir_release,
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.lock = v9fs_file_lock,
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.mmap = generic_file_mmap,
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};
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const struct file_operations v9fs_file_operations = {
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.llseek = generic_file_llseek,
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.read = v9fs_file_read,
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.write = v9fs_file_write,
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.open = v9fs_file_open,
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.release = v9fs_dir_release,
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.lock = v9fs_file_lock,
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.mmap = generic_file_mmap,
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};
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