mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-23 09:19:51 +00:00
![Christophe JAILLET](/assets/img/avatar_default.png)
The 9p fs does not use IDR or IDA functionalities. So there is no point in including <linux/idr.h>. Remove it. Link: https://lkml.kernel.org/r/3d1e0ed9714eaee7e18d9f5b0b4bfa49b00b286d.1669553950.git.christophe.jaillet@wanadoo.fr Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr> Reviewed-by: Christian Schoenebeck <linux_oss@crudebyte.com> [Dominique: reword subject] Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
326 lines
7.4 KiB
C
326 lines
7.4 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
|
|
/*
|
|
* V9FS FID Management
|
|
*
|
|
* Copyright (C) 2007 by Latchesar Ionkov <lucho@ionkov.net>
|
|
* Copyright (C) 2005, 2006 by Eric Van Hensbergen <ericvh@gmail.com>
|
|
*/
|
|
|
|
#include <linux/module.h>
|
|
#include <linux/errno.h>
|
|
#include <linux/fs.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/sched.h>
|
|
#include <net/9p/9p.h>
|
|
#include <net/9p/client.h>
|
|
|
|
#include "v9fs.h"
|
|
#include "v9fs_vfs.h"
|
|
#include "fid.h"
|
|
|
|
static inline void __add_fid(struct dentry *dentry, struct p9_fid *fid)
|
|
{
|
|
hlist_add_head(&fid->dlist, (struct hlist_head *)&dentry->d_fsdata);
|
|
}
|
|
|
|
|
|
/**
|
|
* v9fs_fid_add - add a fid to a dentry
|
|
* @dentry: dentry that the fid is being added to
|
|
* @pfid: fid to add, NULLed out
|
|
*
|
|
*/
|
|
void v9fs_fid_add(struct dentry *dentry, struct p9_fid **pfid)
|
|
{
|
|
struct p9_fid *fid = *pfid;
|
|
|
|
spin_lock(&dentry->d_lock);
|
|
__add_fid(dentry, fid);
|
|
spin_unlock(&dentry->d_lock);
|
|
|
|
*pfid = NULL;
|
|
}
|
|
|
|
/**
|
|
* v9fs_fid_find_inode - search for an open fid off of the inode list
|
|
* @inode: return a fid pointing to a specific inode
|
|
* @uid: return a fid belonging to the specified user
|
|
*
|
|
*/
|
|
|
|
static struct p9_fid *v9fs_fid_find_inode(struct inode *inode, kuid_t uid)
|
|
{
|
|
struct hlist_head *h;
|
|
struct p9_fid *fid, *ret = NULL;
|
|
|
|
p9_debug(P9_DEBUG_VFS, " inode: %p\n", inode);
|
|
|
|
spin_lock(&inode->i_lock);
|
|
h = (struct hlist_head *)&inode->i_private;
|
|
hlist_for_each_entry(fid, h, ilist) {
|
|
if (uid_eq(fid->uid, uid)) {
|
|
p9_fid_get(fid);
|
|
ret = fid;
|
|
break;
|
|
}
|
|
}
|
|
spin_unlock(&inode->i_lock);
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* v9fs_open_fid_add - add an open fid to an inode
|
|
* @inode: inode that the fid is being added to
|
|
* @pfid: fid to add, NULLed out
|
|
*
|
|
*/
|
|
|
|
void v9fs_open_fid_add(struct inode *inode, struct p9_fid **pfid)
|
|
{
|
|
struct p9_fid *fid = *pfid;
|
|
|
|
spin_lock(&inode->i_lock);
|
|
hlist_add_head(&fid->ilist, (struct hlist_head *)&inode->i_private);
|
|
spin_unlock(&inode->i_lock);
|
|
|
|
*pfid = NULL;
|
|
}
|
|
|
|
|
|
/**
|
|
* v9fs_fid_find - retrieve a fid that belongs to the specified uid
|
|
* @dentry: dentry to look for fid in
|
|
* @uid: return fid that belongs to the specified user
|
|
* @any: if non-zero, return any fid associated with the dentry
|
|
*
|
|
*/
|
|
|
|
static struct p9_fid *v9fs_fid_find(struct dentry *dentry, kuid_t uid, int any)
|
|
{
|
|
struct p9_fid *fid, *ret;
|
|
|
|
p9_debug(P9_DEBUG_VFS, " dentry: %pd (%p) uid %d any %d\n",
|
|
dentry, dentry, from_kuid(&init_user_ns, uid),
|
|
any);
|
|
ret = NULL;
|
|
/* we'll recheck under lock if there's anything to look in */
|
|
if (dentry->d_fsdata) {
|
|
struct hlist_head *h = (struct hlist_head *)&dentry->d_fsdata;
|
|
|
|
spin_lock(&dentry->d_lock);
|
|
hlist_for_each_entry(fid, h, dlist) {
|
|
if (any || uid_eq(fid->uid, uid)) {
|
|
ret = fid;
|
|
p9_fid_get(ret);
|
|
break;
|
|
}
|
|
}
|
|
spin_unlock(&dentry->d_lock);
|
|
} else {
|
|
if (dentry->d_inode)
|
|
ret = v9fs_fid_find_inode(dentry->d_inode, uid);
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* We need to hold v9ses->rename_sem as long as we hold references
|
|
* to returned path array. Array element contain pointers to
|
|
* dentry names.
|
|
*/
|
|
static int build_path_from_dentry(struct v9fs_session_info *v9ses,
|
|
struct dentry *dentry, const unsigned char ***names)
|
|
{
|
|
int n = 0, i;
|
|
const unsigned char **wnames;
|
|
struct dentry *ds;
|
|
|
|
for (ds = dentry; !IS_ROOT(ds); ds = ds->d_parent)
|
|
n++;
|
|
|
|
wnames = kmalloc_array(n, sizeof(char *), GFP_KERNEL);
|
|
if (!wnames)
|
|
goto err_out;
|
|
|
|
for (ds = dentry, i = (n-1); i >= 0; i--, ds = ds->d_parent)
|
|
wnames[i] = ds->d_name.name;
|
|
|
|
*names = wnames;
|
|
return n;
|
|
err_out:
|
|
return -ENOMEM;
|
|
}
|
|
|
|
static struct p9_fid *v9fs_fid_lookup_with_uid(struct dentry *dentry,
|
|
kuid_t uid, int any)
|
|
{
|
|
struct dentry *ds;
|
|
const unsigned char **wnames, *uname;
|
|
int i, n, l, access;
|
|
struct v9fs_session_info *v9ses;
|
|
struct p9_fid *fid, *root_fid, *old_fid;
|
|
|
|
v9ses = v9fs_dentry2v9ses(dentry);
|
|
access = v9ses->flags & V9FS_ACCESS_MASK;
|
|
fid = v9fs_fid_find(dentry, uid, any);
|
|
if (fid)
|
|
return fid;
|
|
/*
|
|
* we don't have a matching fid. To do a TWALK we need
|
|
* parent fid. We need to prevent rename when we want to
|
|
* look at the parent.
|
|
*/
|
|
down_read(&v9ses->rename_sem);
|
|
ds = dentry->d_parent;
|
|
fid = v9fs_fid_find(ds, uid, any);
|
|
if (fid) {
|
|
/* Found the parent fid do a lookup with that */
|
|
old_fid = fid;
|
|
|
|
fid = p9_client_walk(old_fid, 1, &dentry->d_name.name, 1);
|
|
p9_fid_put(old_fid);
|
|
goto fid_out;
|
|
}
|
|
up_read(&v9ses->rename_sem);
|
|
|
|
/* start from the root and try to do a lookup */
|
|
root_fid = v9fs_fid_find(dentry->d_sb->s_root, uid, any);
|
|
if (!root_fid) {
|
|
/* the user is not attached to the fs yet */
|
|
if (access == V9FS_ACCESS_SINGLE)
|
|
return ERR_PTR(-EPERM);
|
|
|
|
if (v9fs_proto_dotu(v9ses) || v9fs_proto_dotl(v9ses))
|
|
uname = NULL;
|
|
else
|
|
uname = v9ses->uname;
|
|
|
|
fid = p9_client_attach(v9ses->clnt, NULL, uname, uid,
|
|
v9ses->aname);
|
|
if (IS_ERR(fid))
|
|
return fid;
|
|
|
|
root_fid = p9_fid_get(fid);
|
|
v9fs_fid_add(dentry->d_sb->s_root, &fid);
|
|
}
|
|
/* If we are root ourself just return that */
|
|
if (dentry->d_sb->s_root == dentry)
|
|
return root_fid;
|
|
|
|
/*
|
|
* Do a multipath walk with attached root.
|
|
* When walking parent we need to make sure we
|
|
* don't have a parallel rename happening
|
|
*/
|
|
down_read(&v9ses->rename_sem);
|
|
n = build_path_from_dentry(v9ses, dentry, &wnames);
|
|
if (n < 0) {
|
|
fid = ERR_PTR(n);
|
|
goto err_out;
|
|
}
|
|
fid = root_fid;
|
|
old_fid = root_fid;
|
|
i = 0;
|
|
while (i < n) {
|
|
l = min(n - i, P9_MAXWELEM);
|
|
/*
|
|
* We need to hold rename lock when doing a multipath
|
|
* walk to ensure none of the path components change
|
|
*/
|
|
fid = p9_client_walk(old_fid, l, &wnames[i],
|
|
old_fid == root_fid /* clone */);
|
|
/* non-cloning walk will return the same fid */
|
|
if (fid != old_fid) {
|
|
p9_fid_put(old_fid);
|
|
old_fid = fid;
|
|
}
|
|
if (IS_ERR(fid)) {
|
|
kfree(wnames);
|
|
goto err_out;
|
|
}
|
|
i += l;
|
|
}
|
|
kfree(wnames);
|
|
fid_out:
|
|
if (!IS_ERR(fid)) {
|
|
spin_lock(&dentry->d_lock);
|
|
if (d_unhashed(dentry)) {
|
|
spin_unlock(&dentry->d_lock);
|
|
p9_fid_put(fid);
|
|
fid = ERR_PTR(-ENOENT);
|
|
} else {
|
|
__add_fid(dentry, fid);
|
|
p9_fid_get(fid);
|
|
spin_unlock(&dentry->d_lock);
|
|
}
|
|
}
|
|
err_out:
|
|
up_read(&v9ses->rename_sem);
|
|
return fid;
|
|
}
|
|
|
|
/**
|
|
* v9fs_fid_lookup - lookup for a fid, try to walk if not found
|
|
* @dentry: dentry to look for fid in
|
|
*
|
|
* Look for a fid in the specified dentry for the current user.
|
|
* If no fid is found, try to create one walking from a fid from the parent
|
|
* dentry (if it has one), or the root dentry. If the user haven't accessed
|
|
* the fs yet, attach now and walk from the root.
|
|
*/
|
|
|
|
struct p9_fid *v9fs_fid_lookup(struct dentry *dentry)
|
|
{
|
|
kuid_t uid;
|
|
int any, access;
|
|
struct v9fs_session_info *v9ses;
|
|
|
|
v9ses = v9fs_dentry2v9ses(dentry);
|
|
access = v9ses->flags & V9FS_ACCESS_MASK;
|
|
switch (access) {
|
|
case V9FS_ACCESS_SINGLE:
|
|
case V9FS_ACCESS_USER:
|
|
case V9FS_ACCESS_CLIENT:
|
|
uid = current_fsuid();
|
|
any = 0;
|
|
break;
|
|
|
|
case V9FS_ACCESS_ANY:
|
|
uid = v9ses->uid;
|
|
any = 1;
|
|
break;
|
|
|
|
default:
|
|
uid = INVALID_UID;
|
|
any = 0;
|
|
break;
|
|
}
|
|
return v9fs_fid_lookup_with_uid(dentry, uid, any);
|
|
}
|
|
|
|
struct p9_fid *v9fs_writeback_fid(struct dentry *dentry)
|
|
{
|
|
int err;
|
|
struct p9_fid *fid, *ofid;
|
|
|
|
ofid = v9fs_fid_lookup_with_uid(dentry, GLOBAL_ROOT_UID, 0);
|
|
fid = clone_fid(ofid);
|
|
if (IS_ERR(fid))
|
|
goto error_out;
|
|
p9_fid_put(ofid);
|
|
/*
|
|
* writeback fid will only be used to write back the
|
|
* dirty pages. We always request for the open fid in read-write
|
|
* mode so that a partial page write which result in page
|
|
* read can work.
|
|
*/
|
|
err = p9_client_open(fid, O_RDWR);
|
|
if (err < 0) {
|
|
p9_fid_put(fid);
|
|
fid = ERR_PTR(err);
|
|
goto error_out;
|
|
}
|
|
error_out:
|
|
return fid;
|
|
}
|