From 65b62a29f719e937b5be1df472287f4c61e53ac6 Mon Sep 17 00:00:00 2001
From: Trond Myklebust <Trond.Myklebust@netapp.com>
Date: Thu, 7 Feb 2013 10:54:07 -0500
Subject: NFSv4: Ensure delegation recall and byte range lock removal don't
conflict
Add a mutex to the struct nfs4_state_owner to ensure that delegation
recall doesn't conflict with byte range lock removal.
Note that we nest the new mutex _outside_ the state manager reclaim
protection (nfsi->rwsem) in order to avoid deadlocks.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
---
fs/nfs/nfs4proc.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
(limited to 'fs/nfs/nfs4proc.c')
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index f7e05ade5572..d51227371c67 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -4485,7 +4485,9 @@ static struct rpc_task *nfs4_do_unlck(struct file_lock *fl,
static int nfs4_proc_unlck(struct nfs4_state *state, int cmd, struct file_lock *request)
{
- struct nfs_inode *nfsi = NFS_I(state->inode);
+ struct inode *inode = state->inode;
+ struct nfs4_state_owner *sp = state->owner;
+ struct nfs_inode *nfsi = NFS_I(inode);
struct nfs_seqid *seqid;
struct nfs4_lock_state *lsp;
struct rpc_task *task;
@@ -4495,12 +4497,17 @@ static int nfs4_proc_unlck(struct nfs4_state *state, int cmd, struct file_lock *
status = nfs4_set_lock_state(state, request);
/* Unlock _before_ we do the RPC call */
request->fl_flags |= FL_EXISTS;
+ /* Exclude nfs_delegation_claim_locks() */
+ mutex_lock(&sp->so_delegreturn_mutex);
+ /* Exclude nfs4_reclaim_open_stateid() - note nesting! */
down_read(&nfsi->rwsem);
if (do_vfs_lock(request->fl_file, request) == -ENOENT) {
up_read(&nfsi->rwsem);
+ mutex_unlock(&sp->so_delegreturn_mutex);
goto out;
}
up_read(&nfsi->rwsem);
+ mutex_unlock(&sp->so_delegreturn_mutex);
if (status != 0)
goto out;
/* Is this a delegated lock? */
--
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