static struct ptlrpc_thread gns_thread;
static struct ll_gns_ctl gns_ctl;
-#define CONCUR_GNS_RESTART_APPROACH 0
-
/*
* waits until passed dentry gets mountpoint or timeout and attempts are
* exhausted. Returns 1 if dentry became mountpoint and 0 otherwise.
{
struct l_wait_info lwi;
struct ll_sb_info *sbi;
+ int rc = 0;
ENTRY;
LASSERT(dentry != NULL);
sbi = ll_s2sbi(dentry->d_sb);
lwi = LWI_TIMEOUT(timeout * HZ, NULL, NULL);
- for (; !d_mountpoint(dentry) && tries > 0; tries--)
+ for (; !d_mountpoint(dentry) && tries > 0; tries--) {
l_wait_event(sbi->ll_gns_waitq, d_mountpoint(dentry), &lwi);
-
- if (d_mountpoint(dentry)) {
- spin_lock(&sbi->ll_gns_lock);
- sbi->ll_gns_state = LL_GNS_FINISHED;
- spin_unlock(&sbi->ll_gns_lock);
- RETURN(0);
- }
- RETURN(-ETIME);
-}
-
-#if (CONCUR_GNS_RESTART_APPROACH == 1)
-/*
- * sending a signal known to be ignored to cause restarting syscall if GNS mount
- * function returns -ERESTARTSYS.
- */
-static void
-ll_gns_send_signal(void)
-{
- struct task_struct *task = current;
- int signal = SIGCONT;
-
- read_lock(&tasklist_lock);
- spin_lock_irq(&task->sighand->siglock);
- sigaddset(&task->pending.signal, signal);
- spin_unlock_irq(&task->sighand->siglock);
- read_unlock(&tasklist_lock);
- set_tsk_thread_flag(task, TIF_SIGPENDING);
+ if (signal_pending(current))
+ GOTO(out, rc = -EINTR);
+ }
+
+ if (!d_mountpoint(dentry))
+ rc = -ETIME;
+
+ EXIT;
+out:
+ spin_lock(&sbi->ll_gns_lock);
+ sbi->ll_gns_state = LL_GNS_FINISHED;
+ spin_unlock(&sbi->ll_gns_lock);
+ return rc;
}
-#endif
/*
* tries to mount the mount object under passed @dentry. In the case of success
RETURN(-EINVAL);
spin_lock(&sbi->ll_gns_lock);
-
+
/*
* another thead is in progress or just finished mounting the
* dentry. Handling that.
*/
- if (sbi->ll_gns_state == LL_GNS_MOUNTING ||
- sbi->ll_gns_state == LL_GNS_FINISHED) {
+ if (sbi->ll_gns_state != LL_GNS_IDLE) {
/*
* another thread is trying to mount GNS dentry. We'd like to
* handling that.
*/
spin_unlock(&sbi->ll_gns_lock);
+ restart:
/*
* check if dentry is mount point already, if so, do not restart
* syscal.
if (d_mountpoint(dentry))
RETURN(0);
-#if (CONCUR_GNS_RESTART_APPROACH == 1)
- /*
- * causing syscall to restart and possibly find this dentry
- * already mounted.
- */
- ll_gns_send_signal();
- RETURN(-ERESTARTSYS);
-#else
+ spin_lock(&sbi->ll_gns_lock);
+ if (sbi->ll_gns_pending_dentry &&
+ is_subdir(sbi->ll_gns_pending_dentry, dentry)) {
+ spin_unlock(&sbi->ll_gns_lock);
+ RETURN(-EAGAIN);
+ }
+ spin_unlock(&sbi->ll_gns_lock);
+
/*
* waiting for GNS complete and check dentry again, it may be
* mounted already.
wait_for_completion(&sbi->ll_gns_mount_finished);
if (d_mountpoint(dentry))
RETURN(0);
-#endif
+
+ /*
+ * check for he case when there are few waiters and all they are
+ * awakened, but only one will find GNS state LL_GNS_IDLE, and
+ * the rest will face with LL_GNS_MOUNTING. --umka
+ */
+ spin_lock(&sbi->ll_gns_lock);
+ if (sbi->ll_gns_state != LL_GNS_IDLE) {
+ spin_unlock(&sbi->ll_gns_lock);
+ goto restart;
+ }
+ spin_unlock(&sbi->ll_gns_lock);
}
LASSERT(sbi->ll_gns_state == LL_GNS_IDLE);
-
CDEBUG(D_INODE, "mounting dentry %p\n", dentry);
/* mounting started */
sbi->ll_gns_state = LL_GNS_MOUNTING;
+ sbi->ll_gns_pending_dentry = dentry;
spin_unlock(&sbi->ll_gns_lock);
/* we need to build an absolute pathname to pass to mount */
/*
* recursive lookup with trying to mount SUID bit marked directories on
* the way is not possible here, as lookup_one_len() does not pass @nd
- * to ->lookup() and this is checked in ll_lookup_it(). So, do not
- * handle possible -EAGAIN here.
+ * to ->lookup() and this is checked in ll_lookup_it().
*/
dchild = ll_lookup_one_len(sbi->ll_gns_oname, dentry,
strlen(sbi->ll_gns_oname));
* second.
*/
rc = ll_gns_wait_for_mount(dentry, 1, GNS_WAIT_ATTEMPTS);
- if (rc == 0) {
+ LASSERT(sbi->ll_gns_state == LL_GNS_FINISHED);
+
+ /* checking for mount point anyway to not loss mounts */
+ if (d_mountpoint(dentry)) {
struct dentry *rdentry;
struct vfsmount *rmnt;
- LASSERT(sbi->ll_gns_state == LL_GNS_FINISHED);
-
rmnt = mntget(mnt);
rdentry = dget(dentry);
mntput(mnt);
dput(dentry);
}
+
+ rc = 0;
} else {
CERROR("usermode upcall %s failed to mount %s, err %d\n",
sbi->ll_gns_upcall, path, rc);
case 0:
spin_lock(&sbi->ll_gns_lock);
sbi->ll_gns_state = LL_GNS_IDLE;
+ sbi->ll_gns_pending_dentry = NULL;
spin_unlock(&sbi->ll_gns_lock);
+
+ /* waking up all waiters after GNS state is LL_GNS_IDLE */
complete_all(&sbi->ll_gns_mount_finished);
+ init_completion(&sbi->ll_gns_mount_finished);
}
return rc;
}
git://git.whamcloud.com / fs / lustre-release.git / blobdiff