![Aneesh Kumar K.V](/assets/img/avatar_default.png)
Some of the flags are OS/arch dependent we add a 9p protocol value which maps to asm-generic/fcntl.h values in Linux Based on the original patch from Venkateswararao Jujjuri <jvrao@linux.vnet.ibm.com> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
770 lines
18 KiB
C
770 lines
18 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 <linux/pagemap.h>
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#include <linux/utsname.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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#include "cache.h"
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static const struct vm_operations_struct v9fs_file_vm_ops;
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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_inode *v9inode;
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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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v9inode = V9FS_I(inode);
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v9ses = v9fs_inode2v9ses(inode);
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if (v9fs_proto_dotl(v9ses))
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omode = v9fs_open_to_dotl_flags(file->f_flags);
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else
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omode = v9fs_uflags2omode(file->f_flags,
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v9fs_proto_dotu(v9ses));
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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 (file->f_flags & O_TRUNC) {
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i_size_write(inode, 0);
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inode->i_blocks = 0;
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}
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if ((file->f_flags & O_APPEND) &&
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(!v9fs_proto_dotu(v9ses) && !v9fs_proto_dotl(v9ses)))
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generic_file_llseek(file, 0, SEEK_END);
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}
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file->private_data = fid;
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mutex_lock(&v9inode->v_mutex);
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if (v9ses->cache && !v9inode->writeback_fid &&
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((file->f_flags & O_ACCMODE) != O_RDONLY)) {
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/*
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* clone a fid and add it to writeback_fid
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* we do it during open time instead of
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* page dirty time via write_begin/page_mkwrite
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* because we want write after unlink usecase
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* to work.
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*/
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fid = v9fs_writeback_fid(file->f_path.dentry);
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if (IS_ERR(fid)) {
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err = PTR_ERR(fid);
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mutex_unlock(&v9inode->v_mutex);
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goto out_error;
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}
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v9inode->writeback_fid = (void *) fid;
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}
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mutex_unlock(&v9inode->v_mutex);
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#ifdef CONFIG_9P_FSCACHE
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if (v9ses->cache)
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v9fs_cache_inode_set_cookie(inode, file);
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#endif
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return 0;
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out_error:
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p9_client_clunk(file->private_data);
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file->private_data = NULL;
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return err;
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}
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/**
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* v9fs_file_lock - lock a file (or directory)
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* @filp: file to be locked
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* @cmd: lock command
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* @fl: file lock structure
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*
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* Bugs: 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) && fl->fl_type != F_UNLCK)
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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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static int v9fs_file_do_lock(struct file *filp, int cmd, struct file_lock *fl)
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{
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struct p9_flock flock;
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struct p9_fid *fid;
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uint8_t status;
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int res = 0;
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unsigned char fl_type;
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fid = filp->private_data;
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BUG_ON(fid == NULL);
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if ((fl->fl_flags & FL_POSIX) != FL_POSIX)
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BUG();
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res = posix_lock_file_wait(filp, fl);
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if (res < 0)
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goto out;
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/* convert posix lock to p9 tlock args */
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memset(&flock, 0, sizeof(flock));
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flock.type = fl->fl_type;
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flock.start = fl->fl_start;
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if (fl->fl_end == OFFSET_MAX)
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flock.length = 0;
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else
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flock.length = fl->fl_end - fl->fl_start + 1;
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flock.proc_id = fl->fl_pid;
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flock.client_id = utsname()->nodename;
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if (IS_SETLKW(cmd))
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flock.flags = P9_LOCK_FLAGS_BLOCK;
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/*
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* if its a blocked request and we get P9_LOCK_BLOCKED as the status
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* for lock request, keep on trying
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*/
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for (;;) {
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res = p9_client_lock_dotl(fid, &flock, &status);
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if (res < 0)
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break;
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if (status != P9_LOCK_BLOCKED)
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break;
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if (status == P9_LOCK_BLOCKED && !IS_SETLKW(cmd))
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break;
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schedule_timeout_interruptible(P9_LOCK_TIMEOUT);
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}
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/* map 9p status to VFS status */
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switch (status) {
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case P9_LOCK_SUCCESS:
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res = 0;
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break;
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case P9_LOCK_BLOCKED:
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res = -EAGAIN;
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break;
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case P9_LOCK_ERROR:
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case P9_LOCK_GRACE:
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res = -ENOLCK;
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break;
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default:
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BUG();
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}
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/*
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* incase server returned error for lock request, revert
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* it locally
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*/
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if (res < 0 && fl->fl_type != F_UNLCK) {
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fl_type = fl->fl_type;
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fl->fl_type = F_UNLCK;
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res = posix_lock_file_wait(filp, fl);
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fl->fl_type = fl_type;
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}
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out:
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return res;
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}
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static int v9fs_file_getlock(struct file *filp, struct file_lock *fl)
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{
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struct p9_getlock glock;
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struct p9_fid *fid;
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int res = 0;
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fid = filp->private_data;
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BUG_ON(fid == NULL);
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posix_test_lock(filp, fl);
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/*
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* if we have a conflicting lock locally, no need to validate
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* with server
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*/
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if (fl->fl_type != F_UNLCK)
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return res;
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/* convert posix lock to p9 tgetlock args */
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memset(&glock, 0, sizeof(glock));
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glock.type = fl->fl_type;
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glock.start = fl->fl_start;
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if (fl->fl_end == OFFSET_MAX)
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glock.length = 0;
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else
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glock.length = fl->fl_end - fl->fl_start + 1;
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glock.proc_id = fl->fl_pid;
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glock.client_id = utsname()->nodename;
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res = p9_client_getlock_dotl(fid, &glock);
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if (res < 0)
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return res;
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if (glock.type != F_UNLCK) {
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fl->fl_type = glock.type;
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fl->fl_start = glock.start;
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if (glock.length == 0)
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fl->fl_end = OFFSET_MAX;
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else
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fl->fl_end = glock.start + glock.length - 1;
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fl->fl_pid = glock.proc_id;
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} else
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fl->fl_type = F_UNLCK;
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return res;
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}
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/**
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* v9fs_file_lock_dotl - lock a file (or directory)
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* @filp: file to be locked
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* @cmd: lock command
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* @fl: file lock structure
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*
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*/
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static int v9fs_file_lock_dotl(struct file *filp, int cmd, struct file_lock *fl)
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{
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struct inode *inode = filp->f_path.dentry->d_inode;
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int ret = -ENOLCK;
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P9_DPRINTK(P9_DEBUG_VFS, "filp: %p cmd:%d lock: %p name: %s\n", filp,
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cmd, fl, filp->f_path.dentry->d_name.name);
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/* No mandatory locks */
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if (__mandatory_lock(inode) && fl->fl_type != F_UNLCK)
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goto out_err;
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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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if (IS_SETLK(cmd) || IS_SETLKW(cmd))
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ret = v9fs_file_do_lock(filp, cmd, fl);
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else if (IS_GETLK(cmd))
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ret = v9fs_file_getlock(filp, fl);
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else
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ret = -EINVAL;
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out_err:
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return ret;
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}
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/**
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* v9fs_file_flock_dotl - lock a file
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* @filp: file to be locked
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* @cmd: lock command
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* @fl: file lock structure
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*
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*/
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static int v9fs_file_flock_dotl(struct file *filp, int cmd,
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struct file_lock *fl)
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{
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struct inode *inode = filp->f_path.dentry->d_inode;
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int ret = -ENOLCK;
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P9_DPRINTK(P9_DEBUG_VFS, "filp: %p cmd:%d lock: %p name: %s\n", filp,
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cmd, fl, filp->f_path.dentry->d_name.name);
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/* No mandatory locks */
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if (__mandatory_lock(inode) && fl->fl_type != F_UNLCK)
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goto out_err;
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if (!(fl->fl_flags & FL_FLOCK))
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goto out_err;
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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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/* Convert flock to posix lock */
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fl->fl_owner = (fl_owner_t)filp;
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fl->fl_start = 0;
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fl->fl_end = OFFSET_MAX;
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fl->fl_flags |= FL_POSIX;
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fl->fl_flags ^= FL_FLOCK;
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if (IS_SETLK(cmd) | IS_SETLKW(cmd))
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ret = v9fs_file_do_lock(filp, cmd, fl);
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else
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ret = -EINVAL;
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out_err:
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return ret;
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}
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/**
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* v9fs_fid_readn - read from a fid
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* @fid: fid to read
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* @data: data buffer to read data into
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* @udata: user 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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ssize_t
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v9fs_fid_readn(struct p9_fid *fid, char *data, char __user *udata, u32 count,
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u64 offset)
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{
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int n, total, size;
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P9_DPRINTK(P9_DEBUG_VFS, "fid %d offset %llu count %d\n", fid->fid,
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(long long unsigned) offset, count);
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n = 0;
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total = 0;
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size = fid->iounit ? fid->iounit : fid->clnt->msize - P9_IOHDRSZ;
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do {
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n = p9_client_read(fid, data, udata, offset, count);
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if (n <= 0)
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break;
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if (data)
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data += n;
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if (udata)
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udata += n;
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offset += n;
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count -= n;
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total += n;
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} while (count > 0 && n == size);
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if (n < 0)
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total = n;
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return total;
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}
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/**
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* v9fs_file_readn - read from a file
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* @filp: file pointer to read
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* @data: data buffer to read data into
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* @udata: user 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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ssize_t
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v9fs_file_readn(struct file *filp, char *data, char __user *udata, u32 count,
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u64 offset)
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{
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return v9fs_fid_readn(filp->private_data, data, udata, count, offset);
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}
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/**
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* v9fs_file_read - read from a file
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* @filp: file pointer to read
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* @udata: user 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 *udata, 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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size_t size;
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P9_DPRINTK(P9_DEBUG_VFS, "count %zu offset %lld\n", count, *offset);
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fid = filp->private_data;
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size = fid->iounit ? fid->iounit : fid->clnt->msize - P9_IOHDRSZ;
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if (count > size)
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ret = v9fs_file_readn(filp, NULL, udata, count, *offset);
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else
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ret = p9_client_read(fid, NULL, udata, *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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ssize_t
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v9fs_file_write_internal(struct inode *inode, struct p9_fid *fid,
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const char __user *data, size_t count,
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loff_t *offset, int invalidate)
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{
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int n;
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loff_t i_size;
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size_t total = 0;
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struct p9_client *clnt;
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loff_t origin = *offset;
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unsigned long pg_start, pg_end;
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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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clnt = fid->clnt;
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do {
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n = p9_client_write(fid, NULL, data+total, origin+total, count);
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if (n <= 0)
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break;
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count -= n;
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total += n;
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} while (count > 0);
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if (invalidate && (total > 0)) {
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pg_start = origin >> PAGE_CACHE_SHIFT;
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pg_end = (origin + total - 1) >> PAGE_CACHE_SHIFT;
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if (inode->i_mapping && inode->i_mapping->nrpages)
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invalidate_inode_pages2_range(inode->i_mapping,
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pg_start, pg_end);
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*offset += total;
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i_size = i_size_read(inode);
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if (*offset > i_size) {
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inode_add_bytes(inode, *offset - i_size);
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i_size_write(inode, *offset);
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}
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}
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if (n < 0)
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return n;
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return total;
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}
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/**
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* v9fs_file_write - write to a file
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* @filp: 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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ssize_t retval = 0;
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loff_t origin = *offset;
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retval = generic_write_checks(filp, &origin, &count, 0);
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if (retval)
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goto out;
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|
|
retval = -EINVAL;
|
|
if ((ssize_t) count < 0)
|
|
goto out;
|
|
retval = 0;
|
|
if (!count)
|
|
goto out;
|
|
|
|
retval = v9fs_file_write_internal(filp->f_path.dentry->d_inode,
|
|
filp->private_data,
|
|
data, count, &origin, 1);
|
|
/* update offset on successful write */
|
|
if (retval > 0)
|
|
*offset = origin;
|
|
out:
|
|
return retval;
|
|
}
|
|
|
|
|
|
static int v9fs_file_fsync(struct file *filp, loff_t start, loff_t end,
|
|
int datasync)
|
|
{
|
|
struct p9_fid *fid;
|
|
struct inode *inode = filp->f_mapping->host;
|
|
struct p9_wstat wstat;
|
|
int retval;
|
|
|
|
retval = filemap_write_and_wait_range(inode->i_mapping, start, end);
|
|
if (retval)
|
|
return retval;
|
|
|
|
mutex_lock(&inode->i_mutex);
|
|
P9_DPRINTK(P9_DEBUG_VFS, "filp %p datasync %x\n", filp, datasync);
|
|
|
|
fid = filp->private_data;
|
|
v9fs_blank_wstat(&wstat);
|
|
|
|
retval = p9_client_wstat(fid, &wstat);
|
|
mutex_unlock(&inode->i_mutex);
|
|
|
|
return retval;
|
|
}
|
|
|
|
int v9fs_file_fsync_dotl(struct file *filp, loff_t start, loff_t end,
|
|
int datasync)
|
|
{
|
|
struct p9_fid *fid;
|
|
struct inode *inode = filp->f_mapping->host;
|
|
int retval;
|
|
|
|
retval = filemap_write_and_wait_range(inode->i_mapping, start, end);
|
|
if (retval)
|
|
return retval;
|
|
|
|
mutex_lock(&inode->i_mutex);
|
|
P9_DPRINTK(P9_DEBUG_VFS, "v9fs_file_fsync_dotl: filp %p datasync %x\n",
|
|
filp, datasync);
|
|
|
|
fid = filp->private_data;
|
|
|
|
retval = p9_client_fsync(fid, datasync);
|
|
mutex_unlock(&inode->i_mutex);
|
|
|
|
return retval;
|
|
}
|
|
|
|
static int
|
|
v9fs_file_mmap(struct file *file, struct vm_area_struct *vma)
|
|
{
|
|
int retval;
|
|
|
|
retval = generic_file_mmap(file, vma);
|
|
if (!retval)
|
|
vma->vm_ops = &v9fs_file_vm_ops;
|
|
|
|
return retval;
|
|
}
|
|
|
|
static int
|
|
v9fs_vm_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
|
|
{
|
|
struct v9fs_inode *v9inode;
|
|
struct page *page = vmf->page;
|
|
struct file *filp = vma->vm_file;
|
|
struct inode *inode = filp->f_path.dentry->d_inode;
|
|
|
|
|
|
P9_DPRINTK(P9_DEBUG_VFS, "page %p fid %lx\n",
|
|
page, (unsigned long)filp->private_data);
|
|
|
|
v9inode = V9FS_I(inode);
|
|
/* make sure the cache has finished storing the page */
|
|
v9fs_fscache_wait_on_page_write(inode, page);
|
|
BUG_ON(!v9inode->writeback_fid);
|
|
lock_page(page);
|
|
if (page->mapping != inode->i_mapping)
|
|
goto out_unlock;
|
|
|
|
return VM_FAULT_LOCKED;
|
|
out_unlock:
|
|
unlock_page(page);
|
|
return VM_FAULT_NOPAGE;
|
|
}
|
|
|
|
static ssize_t
|
|
v9fs_direct_read(struct file *filp, char __user *udata, size_t count,
|
|
loff_t *offsetp)
|
|
{
|
|
loff_t size, offset;
|
|
struct inode *inode;
|
|
struct address_space *mapping;
|
|
|
|
offset = *offsetp;
|
|
mapping = filp->f_mapping;
|
|
inode = mapping->host;
|
|
if (!count)
|
|
return 0;
|
|
size = i_size_read(inode);
|
|
if (offset < size)
|
|
filemap_write_and_wait_range(mapping, offset,
|
|
offset + count - 1);
|
|
|
|
return v9fs_file_read(filp, udata, count, offsetp);
|
|
}
|
|
|
|
/**
|
|
* v9fs_cached_file_read - read from a file
|
|
* @filp: file pointer to read
|
|
* @udata: user data buffer to read data into
|
|
* @count: size of buffer
|
|
* @offset: offset at which to read data
|
|
*
|
|
*/
|
|
static ssize_t
|
|
v9fs_cached_file_read(struct file *filp, char __user *data, size_t count,
|
|
loff_t *offset)
|
|
{
|
|
if (filp->f_flags & O_DIRECT)
|
|
return v9fs_direct_read(filp, data, count, offset);
|
|
return do_sync_read(filp, data, count, offset);
|
|
}
|
|
|
|
static ssize_t
|
|
v9fs_direct_write(struct file *filp, const char __user * data,
|
|
size_t count, loff_t *offsetp)
|
|
{
|
|
loff_t offset;
|
|
ssize_t retval;
|
|
struct inode *inode;
|
|
struct address_space *mapping;
|
|
|
|
offset = *offsetp;
|
|
mapping = filp->f_mapping;
|
|
inode = mapping->host;
|
|
if (!count)
|
|
return 0;
|
|
|
|
mutex_lock(&inode->i_mutex);
|
|
retval = filemap_write_and_wait_range(mapping, offset,
|
|
offset + count - 1);
|
|
if (retval)
|
|
goto err_out;
|
|
/*
|
|
* After a write we want buffered reads to be sure to go to disk to get
|
|
* the new data. We invalidate clean cached page from the region we're
|
|
* about to write. We do this *before* the write so that if we fail
|
|
* here we fall back to buffered write
|
|
*/
|
|
if (mapping->nrpages) {
|
|
pgoff_t pg_start = offset >> PAGE_CACHE_SHIFT;
|
|
pgoff_t pg_end = (offset + count - 1) >> PAGE_CACHE_SHIFT;
|
|
|
|
retval = invalidate_inode_pages2_range(mapping,
|
|
pg_start, pg_end);
|
|
/*
|
|
* If a page can not be invalidated, fall back
|
|
* to buffered write.
|
|
*/
|
|
if (retval) {
|
|
if (retval == -EBUSY)
|
|
goto buff_write;
|
|
goto err_out;
|
|
}
|
|
}
|
|
retval = v9fs_file_write(filp, data, count, offsetp);
|
|
err_out:
|
|
mutex_unlock(&inode->i_mutex);
|
|
return retval;
|
|
|
|
buff_write:
|
|
mutex_unlock(&inode->i_mutex);
|
|
return do_sync_write(filp, data, count, offsetp);
|
|
}
|
|
|
|
/**
|
|
* v9fs_cached_file_write - write to a file
|
|
* @filp: file pointer to write
|
|
* @data: data buffer to write data from
|
|
* @count: size of buffer
|
|
* @offset: offset at which to write data
|
|
*
|
|
*/
|
|
static ssize_t
|
|
v9fs_cached_file_write(struct file *filp, const char __user * data,
|
|
size_t count, loff_t *offset)
|
|
{
|
|
|
|
if (filp->f_flags & O_DIRECT)
|
|
return v9fs_direct_write(filp, data, count, offset);
|
|
return do_sync_write(filp, data, count, offset);
|
|
}
|
|
|
|
static const struct vm_operations_struct v9fs_file_vm_ops = {
|
|
.fault = filemap_fault,
|
|
.page_mkwrite = v9fs_vm_page_mkwrite,
|
|
};
|
|
|
|
|
|
const struct file_operations v9fs_cached_file_operations = {
|
|
.llseek = generic_file_llseek,
|
|
.read = v9fs_cached_file_read,
|
|
.write = v9fs_cached_file_write,
|
|
.aio_read = generic_file_aio_read,
|
|
.aio_write = generic_file_aio_write,
|
|
.open = v9fs_file_open,
|
|
.release = v9fs_dir_release,
|
|
.lock = v9fs_file_lock,
|
|
.mmap = v9fs_file_mmap,
|
|
.fsync = v9fs_file_fsync,
|
|
};
|
|
|
|
const struct file_operations v9fs_cached_file_operations_dotl = {
|
|
.llseek = generic_file_llseek,
|
|
.read = v9fs_cached_file_read,
|
|
.write = v9fs_cached_file_write,
|
|
.aio_read = generic_file_aio_read,
|
|
.aio_write = generic_file_aio_write,
|
|
.open = v9fs_file_open,
|
|
.release = v9fs_dir_release,
|
|
.lock = v9fs_file_lock_dotl,
|
|
.flock = v9fs_file_flock_dotl,
|
|
.mmap = v9fs_file_mmap,
|
|
.fsync = v9fs_file_fsync_dotl,
|
|
};
|
|
|
|
const struct file_operations v9fs_file_operations = {
|
|
.llseek = generic_file_llseek,
|
|
.read = v9fs_file_read,
|
|
.write = v9fs_file_write,
|
|
.open = v9fs_file_open,
|
|
.release = v9fs_dir_release,
|
|
.lock = v9fs_file_lock,
|
|
.mmap = generic_file_readonly_mmap,
|
|
.fsync = v9fs_file_fsync,
|
|
};
|
|
|
|
const struct file_operations v9fs_file_operations_dotl = {
|
|
.llseek = generic_file_llseek,
|
|
.read = v9fs_file_read,
|
|
.write = v9fs_file_write,
|
|
.open = v9fs_file_open,
|
|
.release = v9fs_dir_release,
|
|
.lock = v9fs_file_lock_dotl,
|
|
.flock = v9fs_file_flock_dotl,
|
|
.mmap = generic_file_readonly_mmap,
|
|
.fsync = v9fs_file_fsync_dotl,
|
|
};
|