nfs4: treat lock owners as opaque values

Do the following set of ops with a file on a NFSv4 mount:

    exec 3>>/file/on/nfsv4
    flock -x 3
    exec 3>&-

You'll see the LOCK request go across the wire, but no LOCKU when the
file is closed.

What happens is that the fd is passed across a fork, and the final close
is done in a different process than the opener. That makes
__nfs4_find_lock_state miss finding the correct lock state because it
uses the fl_pid as a search key. A new one is created, and the locking
code treats it as a delegation stateid (because NFS_LOCK_INITIALIZED
isn't set).

The root cause of this breakage seems to be commit 77041ed9b49a9e
(NFSv4: Ensure the lockowners are labelled using the fl_owner and/or
fl_pid).

That changed it so that flock lockowners are allocated based on the
fl_pid. I think this is incorrect. flock locks should be "owned" by the
struct file, and that is already accounted for in the fl_owner field of
the lock request when it comes through nfs_flock.

This patch basically reverts the above commit and with it, a LOCKU is
sent in the above reproducer.

Signed-off-by: Jeff Layton <jlayton@poochiereds.net>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

2 files changed, 10 insertions, 48 deletions

diff --git a/fs/nfs/nfs4_fs.h b/fs/nfs/nfs4_fs.h
index b8ea4a26998c..19f567c39670 100644
--- a/fs/nfs/nfs4_fs.h
+++ b/fs/nfs/nfs4_fs.h
@@ -129,17 +129,6 @@ enum {
  * LOCK: one nfs4_state (LOCK) to hold the lock stateid nfs4_state(OPEN)
  */
 
-struct nfs4_lock_owner {
-        unsigned int lo_type;
-#define NFS4_ANY_LOCK_TYPE      (0U)
-#define NFS4_FLOCK_LOCK_TYPE    (1U << 0)
-#define NFS4_POSIX_LOCK_TYPE    (1U << 1)
-        union {
-                fl_owner_t posix_owner;
-                pid_t flock_owner;
-        } lo_u;
-};
-
 struct nfs4_lock_state {
         struct list_head        ls_locks;       /* Other lock stateids */
         struct nfs4_state *     ls_state;       /* Pointer to open state */
@@ -149,7 +138,7 @@ struct nfs4_lock_state {
         struct nfs_seqid_counter        ls_seqid;
         nfs4_stateid            ls_stateid;
         atomic_t                ls_count;
-        struct nfs4_lock_owner  ls_owner;
+        fl_owner_t              ls_owner;
 };
 
 /* bits for nfs4_state->flags */
diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c
index 848f6853c59e..544040835482 100644
--- a/fs/nfs/nfs4state.c
+++ b/fs/nfs/nfs4state.c
@@ -787,21 +787,12 @@ void nfs4_close_sync(struct nfs4_state *state, fmode_t fmode)
  * that is compatible with current->files
  */
 static struct nfs4_lock_state *
-__nfs4_find_lock_state(struct nfs4_state *state, fl_owner_t fl_owner, pid_t fl_pid, unsigned int type)
+__nfs4_find_lock_state(struct nfs4_state *state, fl_owner_t fl_owner)
 {
         struct nfs4_lock_state *pos;
         list_for_each_entry(pos, &state->lock_states, ls_locks) {
-                if (type != NFS4_ANY_LOCK_TYPE && pos->ls_owner.lo_type != type)
+                if (pos->ls_owner != fl_owner)
                         continue;
-                switch (pos->ls_owner.lo_type) {
-                case NFS4_POSIX_LOCK_TYPE:
-                        if (pos->ls_owner.lo_u.posix_owner != fl_owner)
-                                continue;
-                        break;
-                case NFS4_FLOCK_LOCK_TYPE:
-                        if (pos->ls_owner.lo_u.flock_owner != fl_pid)
-                                continue;
-                }
                 atomic_inc(&pos->ls_count);
                 return pos;
         }
@@ -813,7 +804,7 @@ __nfs4_find_lock_state(struct nfs4_state *state, fl_owner_t fl_owner, pid_t fl_p
  * exists, return an uninitialized one.
  *
  */
-static struct nfs4_lock_state *nfs4_alloc_lock_state(struct nfs4_state *state, fl_owner_t fl_owner, pid_t fl_pid, unsigned int type)
+static struct nfs4_lock_state *nfs4_alloc_lock_state(struct nfs4_state *state, fl_owner_t fl_owner)
 {
         struct nfs4_lock_state *lsp;
         struct nfs_server *server = state->owner->so_server;
@@ -824,17 +815,7 @@ static struct nfs4_lock_state *nfs4_alloc_lock_state(struct nfs4_state *state, f
         nfs4_init_seqid_counter(&lsp->ls_seqid);
         atomic_set(&lsp->ls_count, 1);
         lsp->ls_state = state;
-        lsp->ls_owner.lo_type = type;
-        switch (lsp->ls_owner.lo_type) {
-        case NFS4_FLOCK_LOCK_TYPE:
-                lsp->ls_owner.lo_u.flock_owner = fl_pid;
-                break;
-        case NFS4_POSIX_LOCK_TYPE:
-                lsp->ls_owner.lo_u.posix_owner = fl_owner;
-                break;
-        default:
-                goto out_free;
-        }
+        lsp->ls_owner = fl_owner;
         lsp->ls_seqid.owner_id = ida_simple_get(&server->lockowner_id, 0, 0, GFP_NOFS);
         if (lsp->ls_seqid.owner_id < 0)
                 goto out_free;
@@ -857,13 +838,13 @@ void nfs4_free_lock_state(struct nfs_server *server, struct nfs4_lock_state *lsp
  * exists, return an uninitialized one.
  *
  */
-static struct nfs4_lock_state *nfs4_get_lock_state(struct nfs4_state *state, fl_owner_t owner, pid_t pid, unsigned int type)
+static struct nfs4_lock_state *nfs4_get_lock_state(struct nfs4_state *state, fl_owner_t owner)
 {
         struct nfs4_lock_state *lsp, *new = NULL;
         
         for(;;) {
                 spin_lock(&state->state_lock);
-                lsp = __nfs4_find_lock_state(state, owner, pid, type);
+                lsp = __nfs4_find_lock_state(state, owner);
                 if (lsp != NULL)
                         break;
                 if (new != NULL) {
@@ -874,7 +855,7 @@ static struct nfs4_lock_state *nfs4_get_lock_state(struct nfs4_state *state, fl_
                         break;
                 }
                 spin_unlock(&state->state_lock);
-                new = nfs4_alloc_lock_state(state, owner, pid, type);
+                new = nfs4_alloc_lock_state(state, owner);
                 if (new == NULL)
                         return NULL;
         }
@@ -935,13 +916,7 @@ int nfs4_set_lock_state(struct nfs4_state *state, struct file_lock *fl)
 
         if (fl->fl_ops != NULL)
                 return 0;
-        if (fl->fl_flags & FL_POSIX)
-                lsp = nfs4_get_lock_state(state, fl->fl_owner, 0, NFS4_POSIX_LOCK_TYPE);
-        else if (fl->fl_flags & FL_FLOCK)
-                lsp = nfs4_get_lock_state(state, NULL, fl->fl_pid,
-                                NFS4_FLOCK_LOCK_TYPE);
-        else
-                return -EINVAL;
+        lsp = nfs4_get_lock_state(state, fl->fl_owner);
         if (lsp == NULL)
                 return -ENOMEM;
         fl->fl_u.nfs4_fl.owner = lsp;
@@ -955,7 +930,6 @@ static int nfs4_copy_lock_stateid(nfs4_stateid *dst,
 {
         struct nfs4_lock_state *lsp;
         fl_owner_t fl_owner;
-        pid_t fl_pid;
         int ret = -ENOENT;
 
 
@@ -966,9 +940,8 @@ static int nfs4_copy_lock_stateid(nfs4_stateid *dst,
                 goto out;
 
         fl_owner = lockowner->l_owner;
-        fl_pid = lockowner->l_pid;
         spin_lock(&state->state_lock);
-        lsp = __nfs4_find_lock_state(state, fl_owner, fl_pid, NFS4_ANY_LOCK_TYPE);
+        lsp = __nfs4_find_lock_state(state, fl_owner);
         if (lsp && test_bit(NFS_LOCK_LOST, &lsp->ls_flags))
                 ret = -EIO;
         else if (lsp != NULL && test_bit(NFS_LOCK_INITIALIZED, &lsp->ls_flags) != 0) {