[PATCH AUTOSEL for 4.14 003/161] NFSv4: always set NFS_LOCK_LOST when a lock is lost.

Sasha Levin
2018-04-09T03:30:29Z

From: NeilBrown <neilb@suse.com>

[ 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@suse.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
---
fs/nfs/nfs4proc.c | 12 ++++++++----
fs/nfs/nfs4state.c | 5 ++++-
2 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 2241d52710f7..ae8f43d270d6 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -1885,7 +1885,7 @@ static int nfs4_open_reclaim(struct nfs4_state_owner *sp, struct nfs4_state *sta
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:
@@ -1932,7 +1932,11 @@ static int nfs4_handle_delegation_recall_error(struct nfs_server *server, struct
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;
@@ -1968,7 +1972,7 @@ int nfs4_open_delegation_recall(struct nfs_open_context *ctx,
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)
@@ -6595,7 +6599,7 @@ int nfs4_lock_delegation_recall(struct file_lock *fl, struct nfs4_state *state,
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 {
diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c
index 0378e2257ca7..45873ed92057 100644
--- a/fs/nfs/nfs4state.c
+++ b/fs/nfs/nfs4state.c
@@ -1447,6 +1447,7 @@ static int nfs4_reclaim_locks(struct nfs4_state *state, const struct nfs4_state_
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;
@@ -1487,7 +1488,9 @@ 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);
--
2.15.1