From: Marc Eshel <eshel@xxxxxxxxxxxxxxx> - unquoted
Add NFS lock support to GFS2. (Untested.)
Signed-off-by: J. Bruce Fields <bfields@xxxxxxxxxxxxxx>
---
fs/gfs2/locking/dlm/plock.c | 76 +++++++++++++++++++++++++++++++++++++--
fs/gfs2/ops_file.c | 5 +++
include/linux/lock_dlm_plock.h | 3 ++
3 files changed, 80 insertions(+), 4 deletions(-)
diff --git a/fs/gfs2/locking/dlm/plock.c b/fs/gfs2/locking/dlm/plock.c
index 3799f19..da6c01c 100644
--- a/fs/gfs2/locking/dlm/plock.c
+++ b/fs/gfs2/locking/dlm/plock.c
@@ -59,6 +59,8 @@ static void send_op(struct plock_op *op)
wake_up(&send_wq);
}
+/* XXX: unlock? cancel? ... */
+
int gdlm_plock(void *lockspace, struct lm_lockname *name,
struct file *file, int cmd, struct file_lock *fl)
{
@@ -79,9 +81,20 @@ int gdlm_plock(void *lockspace, struct lm_lockname *name,
op->info.start = fl->fl_start;
op->info.end = fl->fl_end;
op->info.owner = (__u64)(long) fl->fl_owner;
+ if (fl->fl_lmops && fl->fl_lmops->fl_notify) {
+ op->info.callback = fl->fl_lmops->fl_notify;
+ /* might need to make a copy */
+ op->info.fl = fl;
+ op->info.file = file;
+ } else
+ op->info.callback = NULL;
send_op(op);
- wait_event(recv_wq, (op->done != 0));
+
+ if (op->info.callback == NULL)
+ wait_event(recv_wq, (op->done != 0));
+ else
+ return -EINPROGRESS;
spin_lock(&ops_lock);
if (!list_empty(&op->list)) {
@@ -103,6 +116,58 @@ int gdlm_plock(void *lockspace, struct lm_lockname *name,
return rv;
}
+/* Returns failure iff a succesful lock operation should be canceled */
+static int gdlm_plock_callback(struct plock_op *op)
+{
+ struct file *file;
+ struct file_lock *fl;
+ int (*notify)(void *, void *, int) = NULL;
+ int rv = 0;
+
+ spin_lock(&ops_lock);
+ if (!list_empty(&op->list)) {
+ printk(KERN_INFO "plock op on list\n");
+ list_del(&op->list);
+ }
+ spin_unlock(&ops_lock);
+
+ /* check if the following 2 are still valid or make a copy */
+ file = op->info.file;
+ fl = op->info.fl;
+ notify = op->info.callback;
+
+ if (op->info.rv) {
+ notify(fl, NULL, op->info.rv);
+ goto out;
+ }
+
+ /* got fs lock; bookkeep locally as well: */
+ if (posix_lock_file(file, fl)) {
+ /*
+ * This can only happen in the case of kmalloc() failure.
+ * The filesystem's own lock is the authoritative lock,
+ * so a failure to get the lock locally is not a disaster.
+ * As long as GFS cannot reliably cancel locks (especially
+ * in a low-memory situation), we're better off ignoring
+ * this failure than trying to recover.
+ */
+ log_error("gdlm_plock: vfs lock error file %p fl %p",
+ file, fl);
+ }
+
+ rv = notify(fl, NULL, 0);
+ if (rv) {
+ /* XXX: We need to cancel the fs lock here: */
+ printk("gfs2 lock granted after lock request failed;"
+ " dangling lock!\n");
+ goto out;
+ }
+
+out:
+ kfree(op);
+ return rv;
+}
+
int gdlm_punlock(void *lockspace, struct lm_lockname *name,
struct file *file, struct file_lock *fl)
{
@@ -243,9 +308,12 @@ static ssize_t dev_write(struct file *file, const char __user *u, size_t count,
}
spin_unlock(&ops_lock);
- if (found)
- wake_up(&recv_wq);
- else
+ if (found) {
+ if (op->info.callback)
+ count = gdlm_plock_callback(op);
+ else
+ wake_up(&recv_wq);
+ } else
printk(KERN_INFO "gdlm dev_write no op %x %llx\n", info.fsid,
(unsigned long long)info.number);
return count;
diff --git a/fs/gfs2/ops_file.c b/fs/gfs2/ops_file.c
index faa07e4..acf23b2 100644
--- a/fs/gfs2/ops_file.c
+++ b/fs/gfs2/ops_file.c
@@ -576,6 +576,11 @@ static int gfs2_lock(struct file *file, int cmd, struct file_lock *fl)
}
}
+ if (cmd == F_CANCELLK) {
+ /* Hack: */
+ cmd = F_SETLK;
+ fl->fl_type = F_UNLCK;
+ }
if (IS_GETLK(cmd))
return gfs2_lm_plock_get(sdp, &name, file, fl);
else if (fl->fl_type == F_UNLCK)
diff --git a/include/linux/lock_dlm_plock.h b/include/linux/lock_dlm_plock.h
index fc34151..809c5b7 100644
--- a/include/linux/lock_dlm_plock.h
+++ b/include/linux/lock_dlm_plock.h
@@ -35,6 +35,9 @@ struct gdlm_plock_info {
__u64 start;
__u64 end;
__u64 owner;
+ void *callback;
+ void *fl;
+ void *file;
};
#endif
--
1.5.0.rc1.g72fe
-
To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
