NFSv4: Fix open_to_lock_owner sequenceid allocation...

NFSv4 file locking is currently completely broken since it doesn't respect
the OPEN sequencing when it is given an unconfirmed lock_owner and needs to
do an open_to_lock_owner. Worse: it breaks the sunrpc rules by doing a
GFP_KERNEL allocation inside an rpciod callback.

Fix is to preallocate the open seqid structure in nfs4_alloc_lockdata if we
see that the lock_owner is unconfirmed.
Then, in nfs4_lock_prepare() we wait for either the open_seqid, if
the lock_owner is still unconfirmed, or else fall back to waiting on the
standard lock_seqid.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 19 insertions, 11 deletions

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 571b5ec92132..9e2e1c7291db 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -3331,6 +3331,12 @@ static struct nfs4_lockdata *nfs4_alloc_lockdata(struct file_lock *fl,
 
         p->arg.fh = NFS_FH(inode);
         p->arg.fl = &p->fl;
+        if (!(lsp->ls_seqid.flags & NFS_SEQID_CONFIRMED)) {
+                p->arg.open_seqid = nfs_alloc_seqid(&lsp->ls_state->owner->so_seqid);
+                if (p->arg.open_seqid == NULL)
+                        goto out_free;
+
+        }
         p->arg.lock_seqid = nfs_alloc_seqid(&lsp->ls_seqid);
         if (p->arg.lock_seqid == NULL)
                 goto out_free;
@@ -3343,6 +3349,8 @@ static struct nfs4_lockdata *nfs4_alloc_lockdata(struct file_lock *fl,
         memcpy(&p->fl, fl, sizeof(p->fl));
         return p;
 out_free:
+        if (p->arg.open_seqid != NULL)
+                nfs_free_seqid(p->arg.open_seqid);
         kfree(p);
         return NULL;
 }
@@ -3359,23 +3367,23 @@ static void nfs4_lock_prepare(struct rpc_task *task, void *calldata)
                 .rpc_cred = sp->so_cred,
         };
 
-        if (nfs_wait_on_sequence(data->arg.lock_seqid, task) != 0)
-                return;
         dprintk("%s: begin!\n", __FUNCTION__);
         /* Do we need to do an open_to_lock_owner? */
         if (!(data->arg.lock_seqid->sequence->flags & NFS_SEQID_CONFIRMED)) {
-                data->arg.open_seqid = nfs_alloc_seqid(&sp->so_seqid);
-                if (data->arg.open_seqid == NULL) {
-                        data->rpc_status = -ENOMEM;
-                        task->tk_action = NULL;
-                        goto out;
-                }
+                if (nfs_wait_on_sequence(data->arg.open_seqid, task) != 0)
+                        return;
                 data->arg.open_stateid = &state->stateid;
                 data->arg.new_lock_owner = 1;
+                /* Retest in case we raced... */
+                if (!(data->arg.lock_seqid->sequence->flags & NFS_SEQID_CONFIRMED))
+                        goto do_rpc;
         }
+        if (nfs_wait_on_sequence(data->arg.lock_seqid, task) != 0)
+                return;
+        data->arg.new_lock_owner = 0;
+do_rpc: 
         data->timestamp = jiffies;
         rpc_call_setup(task, &msg, 0);
-out:
         dprintk("%s: done!, ret = %d\n", __FUNCTION__, data->rpc_status);
 }
 
@@ -3411,8 +3419,6 @@ static void nfs4_lock_release(void *calldata)
         struct nfs4_lockdata *data = calldata;
 
         dprintk("%s: begin!\n", __FUNCTION__);
-        if (data->arg.open_seqid != NULL)
-                nfs_free_seqid(data->arg.open_seqid);
         if (data->cancelled != 0) {
                 struct rpc_task *task;
                 task = nfs4_do_unlck(&data->fl, data->ctx, data->lsp,
@@ -3422,6 +3428,8 @@ static void nfs4_lock_release(void *calldata)
                 dprintk("%s: cancelling lock!\n", __FUNCTION__);
         } else
                 nfs_free_seqid(data->arg.lock_seqid);
+        if (data->arg.open_seqid != NULL)
+                nfs_free_seqid(data->arg.open_seqid);
         nfs4_put_lock_state(data->lsp);
         put_nfs_open_context(data->ctx);
         kfree(data);