[PATCH 4.9 027/329] NFSv4: always set NFS_LOCK_LOST when a lock is lost.

From: Greg Kroah-Hartman
Date: Mon May 28 2018 - 10:57:21 EST


4.9-stable review patch. If anyone has any objections, please let me know.

------------------

From: NeilBrown <neilb@xxxxxxxx>

[ Upstream commit dce2630c7da73b0634686bca557cc8945cc450c8 ]

There are 2 comments in the NFSv4 code which suggest that
SIGLOST should possibly be sent to a process. In these
cases a lock has been lost.
The current practice is to set NFS_LOCK_LOST so that
read/write returns EIO when a lock is lost.
So change these comments to code when sets NFS_LOCK_LOST.

One case is when lock recovery after apparent server restart
fails with NFS4ERR_DENIED, NFS4ERR_RECLAIM_BAD, or
NFS4ERRO_RECLAIM_CONFLICT. The other case is when a lock
attempt as part of lease recovery fails with NFS4ERR_DENIED.

In an ideal world, these should not happen. However I have
a packet trace showing an NFSv4.1 session getting
NFS4ERR_BADSESSION after an extended network parition. The
NFSv4.1 client treats this like server reboot until/unless
it get NFS4ERR_NO_GRACE, in which case it switches over to
"nograce" recovery mode. In this network trace, the client
attempts to recover a lock and the server (incorrectly)
reports NFS4ERR_DENIED rather than NFS4ERR_NO_GRACE. This
leads to the ineffective comment and the client then
continues to write using the OPEN stateid.

Signed-off-by: NeilBrown <neilb@xxxxxxxx>
Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/nfs/nfs4proc.c | 12 ++++++++----
fs/nfs/nfs4state.c | 5 ++++-
2 files changed, 12 insertions(+), 5 deletions(-)

--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -1934,7 +1934,7 @@ static int nfs4_open_reclaim(struct nfs4
return ret;
}

-static int nfs4_handle_delegation_recall_error(struct nfs_server *server, struct nfs4_state *state, const nfs4_stateid *stateid, int err)
+static int nfs4_handle_delegation_recall_error(struct nfs_server *server, struct nfs4_state *state, const nfs4_stateid *stateid, struct file_lock *fl, int err)
{
switch (err) {
default:
@@ -1981,7 +1981,11 @@ static int nfs4_handle_delegation_recall
return -EAGAIN;
case -ENOMEM:
case -NFS4ERR_DENIED:
- /* kill_proc(fl->fl_pid, SIGLOST, 1); */
+ if (fl) {
+ struct nfs4_lock_state *lsp = fl->fl_u.nfs4_fl.owner;
+ if (lsp)
+ set_bit(NFS_LOCK_LOST, &lsp->ls_flags);
+ }
return 0;
}
return err;
@@ -2017,7 +2021,7 @@ int nfs4_open_delegation_recall(struct n
err = nfs4_open_recover_helper(opendata, FMODE_READ);
}
nfs4_opendata_put(opendata);
- return nfs4_handle_delegation_recall_error(server, state, stateid, err);
+ return nfs4_handle_delegation_recall_error(server, state, stateid, NULL, err);
}

static void nfs4_open_confirm_prepare(struct rpc_task *task, void *calldata)
@@ -6499,7 +6503,7 @@ int nfs4_lock_delegation_recall(struct f
if (err != 0)
return err;
err = _nfs4_do_setlk(state, F_SETLK, fl, NFS_LOCK_NEW);
- return nfs4_handle_delegation_recall_error(server, state, stateid, err);
+ return nfs4_handle_delegation_recall_error(server, state, stateid, fl, err);
}

struct nfs_release_lockowner_data {
--- a/fs/nfs/nfs4state.c
+++ b/fs/nfs/nfs4state.c
@@ -1429,6 +1429,7 @@ static int nfs4_reclaim_locks(struct nfs
struct inode *inode = state->inode;
struct nfs_inode *nfsi = NFS_I(inode);
struct file_lock *fl;
+ struct nfs4_lock_state *lsp;
int status = 0;
struct file_lock_context *flctx = inode->i_flctx;
struct list_head *list;
@@ -1469,7 +1470,9 @@ restart:
case -NFS4ERR_DENIED:
case -NFS4ERR_RECLAIM_BAD:
case -NFS4ERR_RECLAIM_CONFLICT:
- /* kill_proc(fl->fl_pid, SIGLOST, 1); */
+ lsp = fl->fl_u.nfs4_fl.owner;
+ if (lsp)
+ set_bit(NFS_LOCK_LOST, &lsp->ls_flags);
status = 0;
}
spin_lock(&flctx->flc_lock);