gfs2: nfs lock support for gfs2
Add NFS lock support to GFS2.
Signed-off-by: Marc Eshel <eshel@almaden.ibm.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Acked-by: Steven Whitehouse <swhiteho@redhat.com>
diff --git a/fs/gfs2/locking/dlm/plock.c b/fs/gfs2/locking/dlm/plock.c
index 1dd4215..f82495e 100644
--- a/fs/gfs2/locking/dlm/plock.c
+++ b/fs/gfs2/locking/dlm/plock.c
@@ -25,6 +25,15 @@
struct gdlm_plock_info info;
};
+struct plock_xop {
+ struct plock_op xop;
+ void *callback;
+ void *fl;
+ void *file;
+ struct file_lock flc;
+};
+
+
static inline void set_version(struct gdlm_plock_info *info)
{
info->version[0] = GDLM_PLOCK_VERSION_MAJOR;
@@ -64,12 +73,14 @@
{
struct gdlm_ls *ls = lockspace;
struct plock_op *op;
+ struct plock_xop *xop;
int rv;
- op = kzalloc(sizeof(*op), GFP_KERNEL);
- if (!op)
+ xop = kzalloc(sizeof(*xop), GFP_KERNEL);
+ if (!xop)
return -ENOMEM;
+ op = &xop->xop;
op->info.optype = GDLM_PLOCK_OP_LOCK;
op->info.pid = fl->fl_pid;
op->info.ex = (fl->fl_type == F_WRLCK);
@@ -79,9 +90,21 @@
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_grant) {
+ xop->callback = fl->fl_lmops->fl_grant;
+ locks_init_lock(&xop->flc);
+ locks_copy_lock(&xop->flc, fl);
+ xop->fl = fl;
+ xop->file = file;
+ } else
+ xop->callback = NULL;
send_op(op);
- wait_event(recv_wq, (op->done != 0));
+
+ if (xop->callback == NULL)
+ wait_event(recv_wq, (op->done != 0));
+ else
+ return -EINPROGRESS;
spin_lock(&ops_lock);
if (!list_empty(&op->list)) {
@@ -99,7 +122,63 @@
(unsigned long long)name->ln_number);
}
- kfree(op);
+ kfree(xop);
+ 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;
+ struct file_lock *flc;
+ int (*notify)(void *, void *, int) = NULL;
+ struct plock_xop *xop = (struct plock_xop *)op;
+ 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 = xop->file;
+ flc = &xop->flc;
+ fl = xop->fl;
+ notify = xop->callback;
+
+ if (op->info.rv) {
+ notify(flc, NULL, op->info.rv);
+ goto out;
+ }
+
+ /* got fs lock; bookkeep locally as well: */
+ flc->fl_flags &= ~FL_SLEEP;
+ if (posix_lock_file(file, flc, NULL)) {
+ /*
+ * 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(flc, 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(xop);
return rv;
}
@@ -138,6 +217,9 @@
rv = op->info.rv;
+ if (rv == -ENOENT)
+ rv = 0;
+
kfree(op);
return rv;
}
@@ -161,6 +243,7 @@
op->info.start = fl->fl_start;
op->info.end = fl->fl_end;
+
send_op(op);
wait_event(recv_wq, (op->done != 0));
@@ -173,9 +256,10 @@
rv = op->info.rv;
- if (rv == 0)
- fl->fl_type = F_UNLCK;
- else if (rv > 0) {
+ fl->fl_type = F_UNLCK;
+ if (rv == -ENOENT)
+ rv = 0;
+ else if (rv == 0 && op->info.pid != fl->fl_pid) {
fl->fl_type = (op->info.ex) ? F_WRLCK : F_RDLCK;
fl->fl_pid = op->info.pid;
fl->fl_start = op->info.start;
@@ -243,9 +327,14 @@
}
spin_unlock(&ops_lock);
- if (found)
- wake_up(&recv_wq);
- else
+ if (found) {
+ struct plock_xop *xop;
+ xop = (struct plock_xop *)op;
+ if (xop->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;