static int sysfs_dentry_revalidate(struct dentry *dentry, unsigned int flags)
{
struct sysfs_dirent *sd;
int type;
if (flags & LOOKUP_RCU)
return -ECHILD;
sd = dentry->d_fsdata;
mutex_lock(&sysfs_mutex);
/* The sysfs dirent has been deleted */
if (sd->s_flags & SYSFS_FLAG_REMOVED)
goto out_bad;
/* The sysfs dirent has been moved? */
if (dentry->d_parent->d_fsdata != sd->s_parent)
goto out_bad;
/* The sysfs dirent has been renamed */
if (strcmp(dentry->d_name.name, sd->s_name) != 0)
goto out_bad;
/* The sysfs dirent has been moved to a different namespace */
type = KOBJ_NS_TYPE_NONE;
if (sd->s_parent) {
type = sysfs_ns_type(sd->s_parent);
if (type != KOBJ_NS_TYPE_NONE &&
sysfs_info(dentry->d_sb)->ns[type] != sd->s_ns)
goto out_bad;
}
mutex_unlock(&sysfs_mutex);
out_valid:
return 1;
out_bad:
/* Remove the dentry from the dcache hashes.
* If this is a deleted dentry we use d_drop instead of d_delete
* so sysfs doesn't need to cope with negative dentries.
*
* If this is a dentry that has simply been renamed we
* use d_drop to remove it from the dcache lookup on its
* old parent. If this dentry persists later when a lookup
* is performed at its new name the dentry will be readded
* to the dcache hashes.
*/
mutex_unlock(&sysfs_mutex);
/* If we have submounts we must allow the vfs caches
* to lie about the state of the filesystem to prevent
* leaks and other nasty things.
*/
if (check_submounts_and_drop(dentry) != 0)
goto out_valid;
return 0;
}
static int kernfs_dop_revalidate(struct dentry *dentry, unsigned int flags)
{
struct kernfs_node *kn;
if (flags & LOOKUP_RCU)
return -ECHILD;
/* Always perform fresh lookup for negatives */
if (!dentry->d_inode)
goto out_bad_unlocked;
kn = dentry->d_fsdata;
mutex_lock(&kernfs_mutex);
/* The kernfs node has been deleted */
if (kn->flags & KERNFS_REMOVED)
goto out_bad;
/* The kernfs node has been moved? */
if (dentry->d_parent->d_fsdata != kn->parent)
goto out_bad;
/* The kernfs node has been renamed */
if (strcmp(dentry->d_name.name, kn->name) != 0)
goto out_bad;
/* The kernfs node has been moved to a different namespace */
if (kn->parent && kernfs_ns_enabled(kn->parent) &&
kernfs_info(dentry->d_sb)->ns != kn->ns)
goto out_bad;
mutex_unlock(&kernfs_mutex);
out_valid:
return 1;
out_bad:
mutex_unlock(&kernfs_mutex);
out_bad_unlocked:
/*
* @dentry doesn't match the underlying kernfs node, drop the
* dentry and force lookup. If we have submounts we must allow the
* vfs caches to lie about the state of the filesystem to prevent
* leaks and other nasty things, so use check_submounts_and_drop()
* instead of d_drop().
*/
if (check_submounts_and_drop(dentry) != 0)
goto out_valid;
return 0;
}
/*
* Check whether the dentry is still valid
*
* If the entry validity timeout has expired and the dentry is
* positive, try to redo the lookup. If the lookup results in a
* different inode, then let the VFS invalidate the dentry and redo
* the lookup once more. If the lookup results in the same inode,
* then refresh the attributes, timeouts and mark the dentry valid.
*/
static int fuse_dentry_revalidate(struct dentry *entry, unsigned int flags)
{
struct inode *inode;
struct dentry *parent;
struct fuse_conn *fc;
int ret;
inode = ACCESS_ONCE(entry->d_inode);
if (inode && is_bad_inode(inode))
goto invalid;
else if (fuse_dentry_time(entry) < get_jiffies_64()) {
int err;
struct fuse_entry_out outarg;
struct fuse_req *req;
struct fuse_forget_link *forget;
u64 attr_version;
/* For negative dentries, always do a fresh lookup */
if (!inode)
goto invalid;
ret = -ECHILD;
if (flags & LOOKUP_RCU)
goto out;
fc = get_fuse_conn(inode);
req = fuse_get_req_nopages(fc);
ret = PTR_ERR(req);
if (IS_ERR(req))
goto out;
forget = fuse_alloc_forget();
if (!forget) {
fuse_put_request(fc, req);
ret = -ENOMEM;
goto out;
}
attr_version = fuse_get_attr_version(fc);
parent = dget_parent(entry);
fuse_lookup_init(fc, req, get_node_id(parent->d_inode),
&entry->d_name, &outarg);
fuse_request_send(fc, req);
dput(parent);
err = req->out.h.error;
fuse_put_request(fc, req);
/* Zero nodeid is same as -ENOENT */
if (!err && !outarg.nodeid)
err = -ENOENT;
if (!err) {
struct fuse_inode *fi = get_fuse_inode(inode);
if (outarg.nodeid != get_node_id(inode)) {
fuse_queue_forget(fc, forget, outarg.nodeid, 1);
goto invalid;
}
spin_lock(&fc->lock);
fi->nlookup++;
spin_unlock(&fc->lock);
}
kfree(forget);
if (err || (outarg.attr.mode ^ inode->i_mode) & S_IFMT)
goto invalid;
fuse_change_attributes(inode, &outarg.attr,
entry_attr_timeout(&outarg),
attr_version);
fuse_change_entry_timeout(entry, &outarg);
} else if (inode) {
fc = get_fuse_conn(inode);
if (fc->readdirplus_auto) {
parent = dget_parent(entry);
fuse_advise_use_readdirplus(parent->d_inode);
dput(parent);
}
}
ret = 1;
out:
return ret;
invalid:
ret = 0;
if (check_submounts_and_drop(entry) != 0)
ret = 1;
goto out;
}
