mirror of https://gitee.com/openkylin/linux.git
127 lines
3.4 KiB
C
127 lines
3.4 KiB
C
/*
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* linux/fs/9p/vfs_dentry.c
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*
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* This file contians vfs dentry ops for the 9P2000 protocol.
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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 as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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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/file.h>
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#include <linux/pagemap.h>
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#include <linux/stat.h>
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#include <linux/string.h>
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#include <linux/smp_lock.h>
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#include <linux/inet.h>
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#include <linux/namei.h>
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#include <linux/idr.h>
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#include "debug.h"
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#include "v9fs.h"
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#include "9p.h"
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#include "v9fs_vfs.h"
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#include "conv.h"
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#include "fid.h"
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/**
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* v9fs_dentry_validate - VFS dcache hook to validate cache
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* @dentry: dentry that is being validated
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* @nd: path data
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*
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* dcache really shouldn't be used for 9P2000 as at all due to
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* potential attached semantics to directory traversal (walk).
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*
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* FUTURE: look into how to use dcache to allow multi-stage
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* walks in Plan 9 & potential for better dcache operation which
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* would remain valid for Plan 9 semantics. Older versions
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* had validation via stat for those interested. However, since
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* stat has the same approximate overhead as walk there really
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* is no difference. The only improvement would be from a
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* time-decay cache like NFS has and that undermines the
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* synchronous nature of 9P2000.
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*
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*/
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static int v9fs_dentry_validate(struct dentry *dentry, struct nameidata *nd)
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{
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struct dentry *dc = current->fs->pwd;
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dprintk(DEBUG_VFS, "dentry: %s (%p)\n", dentry->d_iname, dentry);
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if (v9fs_fid_lookup(dentry)) {
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dprintk(DEBUG_VFS, "VALID\n");
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return 1;
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}
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while (dc != NULL) {
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if (dc == dentry) {
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dprintk(DEBUG_VFS, "VALID\n");
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return 1;
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}
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if (dc == dc->d_parent)
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break;
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dc = dc->d_parent;
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}
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dprintk(DEBUG_VFS, "INVALID\n");
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return 0;
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}
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/**
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* v9fs_dentry_release - called when dentry is going to be freed
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* @dentry: dentry that is being release
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*
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*/
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void v9fs_dentry_release(struct dentry *dentry)
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{
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dprintk(DEBUG_VFS, " dentry: %s (%p)\n", dentry->d_iname, dentry);
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if (dentry->d_fsdata != NULL) {
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struct list_head *fid_list = dentry->d_fsdata;
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struct v9fs_fid *temp = NULL;
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struct v9fs_fid *current_fid = NULL;
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struct v9fs_fcall *fcall = NULL;
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list_for_each_entry_safe(current_fid, temp, fid_list, list) {
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if (v9fs_t_clunk
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(current_fid->v9ses, current_fid->fid, &fcall))
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dprintk(DEBUG_ERROR, "clunk failed: %s\n",
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FCALL_ERROR(fcall));
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v9fs_put_idpool(current_fid->fid,
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¤t_fid->v9ses->fidpool);
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kfree(fcall);
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v9fs_fid_destroy(current_fid);
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}
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kfree(dentry->d_fsdata); /* free the list_head */
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}
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}
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struct dentry_operations v9fs_dentry_operations = {
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.d_revalidate = v9fs_dentry_validate,
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.d_release = v9fs_dentry_release,
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};
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