static int
sid_to_id(struct cifs_sb_info *cifs_sb, struct cifs_sid *psid,
struct cifs_fattr *fattr, uint sidtype)
{
int rc;
unsigned long cid;
struct key *idkey;
const struct cred *saved_cred;
struct cifs_sid_id *psidid, *npsidid;
struct rb_root *cidtree;
spinlock_t *cidlock;
if (sidtype == SIDOWNER) {
cid = cifs_sb->mnt_uid;
cidlock = &siduidlock;
cidtree = &uidtree;
} else if (sidtype == SIDGROUP) {
cid = cifs_sb->mnt_gid;
cidlock = &sidgidlock;
cidtree = &gidtree;
} else
return -ENOENT;
spin_lock(cidlock);
psidid = id_rb_search(cidtree, psid);
if (!psidid) {
spin_unlock(cidlock);
npsidid = kzalloc(sizeof(struct cifs_sid_id), GFP_KERNEL);
if (!npsidid)
return -ENOMEM;
npsidid->sidstr = kmalloc(SIDLEN, GFP_KERNEL);
if (!npsidid->sidstr) {
kfree(npsidid);
return -ENOMEM;
}
spin_lock(cidlock);
psidid = id_rb_search(cidtree, psid);
if (psidid) {
++psidid->refcount;
spin_unlock(cidlock);
kfree(npsidid->sidstr);
kfree(npsidid);
} else {
psidid = npsidid;
id_rb_insert(cidtree, psid, &psidid,
sidtype == SIDOWNER ? "os:" : "gs:");
++psidid->refcount;
spin_unlock(cidlock);
}
} else {
++psidid->refcount;
spin_unlock(cidlock);
}
if (test_bit(SID_ID_MAPPED, &psidid->state)) {
cid = psidid->id;
psidid->time = jiffies;
goto sid_to_id_out;
}
if (time_after(psidid->time + SID_MAP_RETRY, jiffies))
goto sid_to_id_out;
if (!test_and_set_bit(SID_ID_PENDING, &psidid->state)) {
saved_cred = override_creds(root_cred);
idkey = request_key(&cifs_idmap_key_type, psidid->sidstr, "");
if (IS_ERR(idkey))
cFYI(1, "%s: Can't map SID to an id", __func__);
else {
cid = *(unsigned long *)idkey->payload.value;
psidid->id = cid;
set_bit(SID_ID_MAPPED, &psidid->state);
key_put(idkey);
kfree(psidid->sidstr);
}
revert_creds(saved_cred);
psidid->time = jiffies;
clear_bit(SID_ID_PENDING, &psidid->state);
wake_up_bit(&psidid->state, SID_ID_PENDING);
} else {
rc = wait_on_bit(&psidid->state, SID_ID_PENDING,
sidid_pending_wait, TASK_INTERRUPTIBLE);
if (rc) {
cFYI(1, "%s: sidid_pending_wait interrupted %d",
__func__, rc);
--psidid->refcount;
return rc;
}
if (test_bit(SID_ID_MAPPED, &psidid->state))
cid = psidid->id;
}
sid_to_id_out:
--psidid->refcount;
if (sidtype == SIDOWNER)
fattr->cf_uid = cid;
else
fattr->cf_gid = cid;
return 0;
}
static int
sid_to_id(struct cifs_sb_info *cifs_sb, struct cifs_sid *psid,
struct cifs_fattr *fattr, uint sidtype)
{
int rc;
unsigned long cid;
struct key *idkey;
const struct cred *saved_cred;
struct cifs_sid_id *psidid, *npsidid;
struct rb_root *cidtree;
spinlock_t *cidlock;
if (sidtype == SIDOWNER) {
cid = cifs_sb->mnt_uid; /* default uid, in case upcall fails */
cidlock = &siduidlock;
cidtree = &uidtree;
} else if (sidtype == SIDGROUP) {
cid = cifs_sb->mnt_gid; /* default gid, in case upcall fails */
cidlock = &sidgidlock;
cidtree = &gidtree;
} else
return -ENOENT;
spin_lock(cidlock);
psidid = id_rb_search(cidtree, psid);
if (!psidid) { /* node does not exist, allocate one & attempt adding */
spin_unlock(cidlock);
npsidid = kzalloc(sizeof(struct cifs_sid_id), GFP_KERNEL);
if (!npsidid)
return -ENOMEM;
npsidid->sidstr = kmalloc(SIDLEN, GFP_KERNEL);
if (!npsidid->sidstr) {
kfree(npsidid);
return -ENOMEM;
}
spin_lock(cidlock);
psidid = id_rb_search(cidtree, psid);
if (psidid) { /* node happened to get inserted meanwhile */
++psidid->refcount;
spin_unlock(cidlock);
kfree(npsidid->sidstr);
kfree(npsidid);
} else {
psidid = npsidid;
id_rb_insert(cidtree, psid, &psidid,
sidtype == SIDOWNER ? "os:" : "gs:");
++psidid->refcount;
spin_unlock(cidlock);
}
} else {
++psidid->refcount;
spin_unlock(cidlock);
}
/*
* If we are here, it is safe to access psidid and its fields
* since a reference was taken earlier while holding the spinlock.
* A reference on the node is put without holding the spinlock
* and it is OK to do so in this case, shrinker will not erase
* this node until all references are put and we do not access
* any fields of the node after a reference is put .
*/
if (test_bit(SID_ID_MAPPED, &psidid->state)) {
cid = psidid->id;
psidid->time = jiffies; /* update ts for accessing */
goto sid_to_id_out;
}
if (time_after(psidid->time + SID_MAP_RETRY, jiffies))
goto sid_to_id_out;
if (!test_and_set_bit(SID_ID_PENDING, &psidid->state)) {
saved_cred = override_creds(root_cred);
idkey = request_key(&cifs_idmap_key_type, psidid->sidstr, "");
if (IS_ERR(idkey))
cFYI(1, "%s: Can't map SID to an id", __func__);
else {
cid = *(unsigned long *)idkey->payload.value;
psidid->id = cid;
set_bit(SID_ID_MAPPED, &psidid->state);
key_put(idkey);
kfree(psidid->sidstr);
}
revert_creds(saved_cred);
psidid->time = jiffies; /* update ts for accessing */
clear_bit(SID_ID_PENDING, &psidid->state);
wake_up_bit(&psidid->state, SID_ID_PENDING);
} else {
rc = wait_on_bit(&psidid->state, SID_ID_PENDING,
sidid_pending_wait, TASK_INTERRUPTIBLE);
if (rc) {
cFYI(1, "%s: sidid_pending_wait interrupted %d",
__func__, rc);
--psidid->refcount; /* decremented without spinlock */
return rc;
}
if (test_bit(SID_ID_MAPPED, &psidid->state))
cid = psidid->id;
}
sid_to_id_out:
--psidid->refcount; /* decremented without spinlock */
if (sidtype == SIDOWNER)
fattr->cf_uid = cid;
else
fattr->cf_gid = cid;
return 0;
}
