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348b59012e
This helps in more control over debugging. root@qemu-img-64:~# ls /pass/123 ls: cannot access /pass/123: No such file or directory root@qemu-img-64:~# cat /sys/kernel/debug/tracing/trace # tracer: nop # # TASK-PID CPU# TIMESTAMP FUNCTION # | | | | | ls-1536 [001] 70.928584: 9p_protocol_dump: clnt 18446612132784021504 P9_TWALK(tag = 1) 000: 16 00 00 00 6e 01 00 01 00 00 00 02 00 00 00 01 010: 00 03 00 31 32 33 00 00 00 ff ff ff ff 00 00 00 ls-1536 [001] 70.928587: <stack trace> => trace_9p_protocol_dump => p9pdu_finalize => p9_client_rpc => p9_client_walk => v9fs_vfs_lookup => d_alloc_and_lookup => walk_component => path_lookupat ls-1536 [000] 70.929696: 9p_protocol_dump: clnt 18446612132784021504 P9_RLERROR(tag = 1) 000: 0b 00 00 00 07 01 00 02 00 00 00 4e 03 00 02 00 010: 00 00 00 00 03 00 02 00 00 00 00 00 ff 43 00 00 ls-1536 [000] 70.929697: <stack trace> => trace_9p_protocol_dump => p9_client_rpc => p9_client_walk => v9fs_vfs_lookup => d_alloc_and_lookup => walk_component => path_lookupat => do_path_lookup Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
317 lines
6.9 KiB
C
317 lines
6.9 KiB
C
/*
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* linux/fs/9p/vfs_dir.c
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*
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* This file contains vfs directory 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 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/file.h>
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#include <linux/stat.h>
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#include <linux/string.h>
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#include <linux/sched.h>
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#include <linux/inet.h>
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#include <linux/idr.h>
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#include <linux/slab.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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/**
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* struct p9_rdir - readdir accounting
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* @mutex: mutex protecting readdir
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* @head: start offset of current dirread buffer
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* @tail: end offset of current dirread buffer
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* @buf: dirread buffer
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*
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* private structure for keeping track of readdir
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* allocated on demand
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*/
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struct p9_rdir {
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struct mutex mutex;
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int head;
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int tail;
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uint8_t *buf;
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};
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/**
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* dt_type - return file type
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* @mistat: mistat structure
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*
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*/
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static inline int dt_type(struct p9_wstat *mistat)
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{
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unsigned long perm = mistat->mode;
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int rettype = DT_REG;
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if (perm & P9_DMDIR)
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rettype = DT_DIR;
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if (perm & P9_DMSYMLINK)
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rettype = DT_LNK;
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return rettype;
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}
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static void p9stat_init(struct p9_wstat *stbuf)
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{
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stbuf->name = NULL;
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stbuf->uid = NULL;
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stbuf->gid = NULL;
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stbuf->muid = NULL;
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stbuf->extension = NULL;
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}
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/**
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* v9fs_alloc_rdir_buf - Allocate buffer used for read and readdir
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* @filp: opened file structure
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* @buflen: Length in bytes of buffer to allocate
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*
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*/
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static int v9fs_alloc_rdir_buf(struct file *filp, int buflen)
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{
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struct p9_rdir *rdir;
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struct p9_fid *fid;
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int err = 0;
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fid = filp->private_data;
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if (!fid->rdir) {
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rdir = kmalloc(sizeof(struct p9_rdir) + buflen, GFP_KERNEL);
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if (rdir == NULL) {
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err = -ENOMEM;
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goto exit;
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}
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spin_lock(&filp->f_dentry->d_lock);
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if (!fid->rdir) {
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rdir->buf = (uint8_t *)rdir + sizeof(struct p9_rdir);
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mutex_init(&rdir->mutex);
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rdir->head = rdir->tail = 0;
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fid->rdir = (void *) rdir;
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rdir = NULL;
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}
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spin_unlock(&filp->f_dentry->d_lock);
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kfree(rdir);
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}
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exit:
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return err;
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}
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/**
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* v9fs_dir_readdir - read a directory
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* @filp: opened file structure
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* @dirent: directory structure ???
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* @filldir: function to populate directory structure ???
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*
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*/
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static int v9fs_dir_readdir(struct file *filp, void *dirent, filldir_t filldir)
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{
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int over;
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struct p9_wstat st;
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int err = 0;
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struct p9_fid *fid;
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int buflen;
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int reclen = 0;
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struct p9_rdir *rdir;
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P9_DPRINTK(P9_DEBUG_VFS, "name %s\n", filp->f_path.dentry->d_name.name);
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fid = filp->private_data;
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buflen = fid->clnt->msize - P9_IOHDRSZ;
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err = v9fs_alloc_rdir_buf(filp, buflen);
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if (err)
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goto exit;
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rdir = (struct p9_rdir *) fid->rdir;
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err = mutex_lock_interruptible(&rdir->mutex);
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if (err)
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return err;
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while (err == 0) {
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if (rdir->tail == rdir->head) {
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err = v9fs_file_readn(filp, rdir->buf, NULL,
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buflen, filp->f_pos);
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if (err <= 0)
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goto unlock_and_exit;
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rdir->head = 0;
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rdir->tail = err;
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}
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while (rdir->head < rdir->tail) {
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p9stat_init(&st);
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err = p9stat_read(fid->clnt, rdir->buf + rdir->head,
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rdir->tail - rdir->head, &st);
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if (err) {
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P9_DPRINTK(P9_DEBUG_VFS, "returned %d\n", err);
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err = -EIO;
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p9stat_free(&st);
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goto unlock_and_exit;
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}
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reclen = st.size+2;
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over = filldir(dirent, st.name, strlen(st.name),
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filp->f_pos, v9fs_qid2ino(&st.qid), dt_type(&st));
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p9stat_free(&st);
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if (over) {
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err = 0;
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goto unlock_and_exit;
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}
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rdir->head += reclen;
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filp->f_pos += reclen;
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}
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}
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unlock_and_exit:
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mutex_unlock(&rdir->mutex);
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exit:
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return err;
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}
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/**
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* v9fs_dir_readdir_dotl - read a directory
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* @filp: opened file structure
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* @dirent: buffer to fill dirent structures
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* @filldir: function to populate dirent structures
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*
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*/
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static int v9fs_dir_readdir_dotl(struct file *filp, void *dirent,
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filldir_t filldir)
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{
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int over;
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int err = 0;
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struct p9_fid *fid;
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int buflen;
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struct p9_rdir *rdir;
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struct p9_dirent curdirent;
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u64 oldoffset = 0;
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P9_DPRINTK(P9_DEBUG_VFS, "name %s\n", filp->f_path.dentry->d_name.name);
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fid = filp->private_data;
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buflen = fid->clnt->msize - P9_READDIRHDRSZ;
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err = v9fs_alloc_rdir_buf(filp, buflen);
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if (err)
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goto exit;
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rdir = (struct p9_rdir *) fid->rdir;
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err = mutex_lock_interruptible(&rdir->mutex);
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if (err)
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return err;
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while (err == 0) {
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if (rdir->tail == rdir->head) {
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err = p9_client_readdir(fid, rdir->buf, buflen,
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filp->f_pos);
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if (err <= 0)
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goto unlock_and_exit;
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rdir->head = 0;
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rdir->tail = err;
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}
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while (rdir->head < rdir->tail) {
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err = p9dirent_read(fid->clnt, rdir->buf + rdir->head,
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rdir->tail - rdir->head,
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&curdirent);
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if (err < 0) {
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P9_DPRINTK(P9_DEBUG_VFS, "returned %d\n", err);
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err = -EIO;
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goto unlock_and_exit;
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}
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/* d_off in dirent structure tracks the offset into
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* the next dirent in the dir. However, filldir()
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* expects offset into the current dirent. Hence
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* while calling filldir send the offset from the
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* previous dirent structure.
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*/
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over = filldir(dirent, curdirent.d_name,
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strlen(curdirent.d_name),
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oldoffset, v9fs_qid2ino(&curdirent.qid),
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curdirent.d_type);
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oldoffset = curdirent.d_off;
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if (over) {
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err = 0;
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goto unlock_and_exit;
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}
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filp->f_pos = curdirent.d_off;
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rdir->head += err;
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}
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}
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unlock_and_exit:
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mutex_unlock(&rdir->mutex);
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exit:
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return err;
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}
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/**
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* v9fs_dir_release - close a directory
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* @inode: inode of the directory
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* @filp: file pointer to a directory
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*
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*/
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int v9fs_dir_release(struct inode *inode, struct file *filp)
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{
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struct p9_fid *fid;
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fid = filp->private_data;
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P9_DPRINTK(P9_DEBUG_VFS,
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"v9fs_dir_release: inode: %p filp: %p fid: %d\n",
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inode, filp, fid ? fid->fid : -1);
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if (fid)
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p9_client_clunk(fid);
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return 0;
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}
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const struct file_operations v9fs_dir_operations = {
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.read = generic_read_dir,
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.llseek = generic_file_llseek,
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.readdir = v9fs_dir_readdir,
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.open = v9fs_file_open,
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.release = v9fs_dir_release,
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};
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const struct file_operations v9fs_dir_operations_dotl = {
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.read = generic_read_dir,
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.llseek = generic_file_llseek,
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.readdir = v9fs_dir_readdir_dotl,
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.open = v9fs_file_open,
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.release = v9fs_dir_release,
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.fsync = v9fs_file_fsync_dotl,
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};
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