This series aims to correct the fl_pid value for locks held by the NLM
server, or lockd. It applies onto the revert of the previous attempt to fix
this problem sent ealier this week: '[PATCH] Revert "lockd: Show pid of
lockd for remote locks"'.
The problem with the earlier attempt was that we discarded the svid, and so
we couldn't distinguish remote lockowners on each host. It is necessary to
turn the svid and host into a distinct owner.
We can take a page from the NLM client and make an allocation to track the
svid and host together, which is what we do here. The mechanisms to do so
aren't quite similar enough to generalize, but I did share the nlm_lockowner
structure. There is one field unsed on the server: nlm_lockowner.owner.
It turns out that the LTP's testcases/network/nfsv4/locks/locktests.c was
useful for testing this, as it coordinates locking tests amongst NFS
clients.
Changes on:
v2 - Fixed typos in commit log messages, and whitespace.
Benjamin Coddington (5):
lockd: prepare nlm_lockowner for use by the server
lockd: Convert NLM service fl_owner to nlm_lockowner
lockd: Remove lm_compare_owner and lm_owner_key
lockd: Show pid of lockd for remote locks
locks: Cleanup lm_compare_owner and lm_owner_key
Documentation/filesystems/Locking | 14 ----
fs/lockd/clntproc.c | 21 +++---
fs/lockd/svc4proc.c | 14 +++-
fs/lockd/svclock.c | 118 +++++++++++++++++++++++++-----
fs/lockd/svcproc.c | 14 +++-
fs/lockd/svcsubs.c | 2 +-
fs/lockd/xdr.c | 3 -
fs/lockd/xdr4.c | 3 -
fs/locks.c | 5 --
include/linux/fs.h | 2 -
include/linux/lockd/lockd.h | 2 +
11 files changed, 138 insertions(+), 60 deletions(-)
--
2.20.1
Do as the NLM client: allocate and track a struct nlm_lockowner for use as
the fl_owner for locks created by the NLM sever. This allows us to keep
the svid within this structure for matching locks, and will allow us to
track the pid of lockd in a future patch. It should also allow easier
reference of the nlm_host in conflicting locks, and simplify lock hashing
and comparison.
Signed-off-by: Benjamin Coddington <[email protected]>
---
fs/lockd/svc4proc.c | 13 ++++-
fs/lockd/svclock.c | 96 +++++++++++++++++++++++++++++++++++++
fs/lockd/svcproc.c | 13 ++++-
fs/lockd/svcsubs.c | 2 +-
fs/lockd/xdr.c | 1 -
fs/lockd/xdr4.c | 1 -
include/linux/lockd/lockd.h | 2 +
7 files changed, 123 insertions(+), 5 deletions(-)
diff --git a/fs/lockd/svc4proc.c b/fs/lockd/svc4proc.c
index 1bddf70d9656..90d328d61933 100644
--- a/fs/lockd/svc4proc.c
+++ b/fs/lockd/svc4proc.c
@@ -46,8 +46,13 @@ nlm4svc_retrieve_args(struct svc_rqst *rqstp, struct nlm_args *argp,
/* Set up the missing parts of the file_lock structure */
lock->fl.fl_file = file->f_file;
- lock->fl.fl_owner = (fl_owner_t) host;
lock->fl.fl_lmops = &nlmsvc_lock_operations;
+ nlmsvc_locks_init_private(&lock->fl, host, (pid_t)lock->svid);
+ if (!lock->fl.fl_owner) {
+ /* lockowner allocation has failed */
+ nlmsvc_release_host(host);
+ return -ENOMEM;
+ }
}
return 0;
@@ -94,6 +99,7 @@ __nlm4svc_proc_test(struct svc_rqst *rqstp, struct nlm_res *resp)
else
dprintk("lockd: TEST4 status %d\n", ntohl(resp->status));
+ nlmsvc_release_lockowner(&argp->lock);
nlmsvc_release_host(host);
nlm_release_file(file);
return rc;
@@ -142,6 +148,7 @@ __nlm4svc_proc_lock(struct svc_rqst *rqstp, struct nlm_res *resp)
else
dprintk("lockd: LOCK status %d\n", ntohl(resp->status));
+ nlmsvc_release_lockowner(&argp->lock);
nlmsvc_release_host(host);
nlm_release_file(file);
return rc;
@@ -178,6 +185,7 @@ __nlm4svc_proc_cancel(struct svc_rqst *rqstp, struct nlm_res *resp)
resp->status = nlmsvc_cancel_blocked(SVC_NET(rqstp), file, &argp->lock);
dprintk("lockd: CANCEL status %d\n", ntohl(resp->status));
+ nlmsvc_release_lockowner(&argp->lock);
nlmsvc_release_host(host);
nlm_release_file(file);
return rpc_success;
@@ -217,6 +225,7 @@ __nlm4svc_proc_unlock(struct svc_rqst *rqstp, struct nlm_res *resp)
resp->status = nlmsvc_unlock(SVC_NET(rqstp), file, &argp->lock);
dprintk("lockd: UNLOCK status %d\n", ntohl(resp->status));
+ nlmsvc_release_lockowner(&argp->lock);
nlmsvc_release_host(host);
nlm_release_file(file);
return rpc_success;
@@ -365,6 +374,7 @@ nlm4svc_proc_share(struct svc_rqst *rqstp)
resp->status = nlmsvc_share_file(host, file, argp);
dprintk("lockd: SHARE status %d\n", ntohl(resp->status));
+ nlmsvc_release_lockowner(&argp->lock);
nlmsvc_release_host(host);
nlm_release_file(file);
return rpc_success;
@@ -399,6 +409,7 @@ nlm4svc_proc_unshare(struct svc_rqst *rqstp)
resp->status = nlmsvc_unshare_file(host, file, argp);
dprintk("lockd: UNSHARE status %d\n", ntohl(resp->status));
+ nlmsvc_release_lockowner(&argp->lock);
nlmsvc_release_host(host);
nlm_release_file(file);
return rpc_success;
diff --git a/fs/lockd/svclock.c b/fs/lockd/svclock.c
index ea719cdd6a36..34c6ee85274e 100644
--- a/fs/lockd/svclock.c
+++ b/fs/lockd/svclock.c
@@ -332,6 +332,93 @@ void nlmsvc_traverse_blocks(struct nlm_host *host,
mutex_unlock(&file->f_mutex);
}
+static struct nlm_lockowner *
+nlmsvc_get_lockowner(struct nlm_lockowner *lockowner)
+{
+ refcount_inc(&lockowner->count);
+ return lockowner;
+}
+
+static void nlmsvc_put_lockowner(struct nlm_lockowner *lockowner)
+{
+ if (!refcount_dec_and_lock(&lockowner->count, &lockowner->host->h_lock))
+ return;
+ list_del(&lockowner->list);
+ spin_unlock(&lockowner->host->h_lock);
+ nlmsvc_release_host(lockowner->host);
+ kfree(lockowner);
+}
+
+static struct nlm_lockowner *__nlmsvc_find_lockowner(struct nlm_host *host, pid_t pid)
+{
+ struct nlm_lockowner *lockowner;
+ list_for_each_entry(lockowner, &host->h_lockowners, list) {
+ if (lockowner->pid != pid)
+ continue;
+ return nlmsvc_get_lockowner(lockowner);
+ }
+ return NULL;
+}
+
+static struct nlm_lockowner *nlmsvc_find_lockowner(struct nlm_host *host, pid_t pid)
+{
+ struct nlm_lockowner *res, *new = NULL;
+
+ spin_lock(&host->h_lock);
+ res = __nlmsvc_find_lockowner(host, pid);
+
+ if (res == NULL) {
+ spin_unlock(&host->h_lock);
+ new = kmalloc(sizeof(*res), GFP_KERNEL);
+ spin_lock(&host->h_lock);
+ res = __nlmsvc_find_lockowner(host, pid);
+ if (res == NULL && new != NULL) {
+ res = new;
+ /* fs/locks.c will manage the refcount through lock_ops */
+ refcount_set(&new->count, 1);
+ new->pid = pid;
+ new->host = nlm_get_host(host);
+ list_add(&new->list, &host->h_lockowners);
+ new = NULL;
+ }
+ }
+
+ spin_unlock(&host->h_lock);
+ kfree(new);
+ return res;
+}
+
+void
+nlmsvc_release_lockowner(struct nlm_lock *lock)
+{
+ if (lock->fl.fl_owner)
+ nlmsvc_put_lockowner(lock->fl.fl_owner);
+}
+
+static void nlmsvc_locks_copy_lock(struct file_lock *new, struct file_lock *fl)
+{
+ struct nlm_lockowner *nlm_lo = (struct nlm_lockowner *)fl->fl_owner;
+ new->fl_owner = nlmsvc_get_lockowner(nlm_lo);
+}
+
+static void nlmsvc_locks_release_private(struct file_lock *fl)
+{
+ nlmsvc_put_lockowner((struct nlm_lockowner *)fl->fl_owner);
+}
+
+const struct file_lock_operations nlmsvc_lock_ops = {
+ .fl_copy_lock = nlmsvc_locks_copy_lock,
+ .fl_release_private = nlmsvc_locks_release_private,
+};
+
+void nlmsvc_locks_init_private(struct file_lock *fl, struct nlm_host *host,
+ pid_t pid)
+{
+ fl->fl_owner = nlmsvc_find_lockowner(host, pid);
+ if (fl->fl_owner != NULL)
+ fl->fl_ops = &nlmsvc_lock_ops;
+}
+
/*
* Initialize arguments for GRANTED call. The nlm_rqst structure
* has been cleared already.
@@ -509,6 +596,7 @@ nlmsvc_testlock(struct svc_rqst *rqstp, struct nlm_file *file,
{
int error;
__be32 ret;
+ struct nlm_lockowner *test_owner;
dprintk("lockd: nlmsvc_testlock(%s/%ld, ty=%d, %Ld-%Ld)\n",
locks_inode(file->f_file)->i_sb->s_id,
@@ -522,6 +610,9 @@ nlmsvc_testlock(struct svc_rqst *rqstp, struct nlm_file *file,
goto out;
}
+ /* If there's a conflicting lock, remember to clean up the test lock */
+ test_owner = (struct nlm_lockowner *)lock->fl.fl_owner;
+
error = vfs_test_lock(file->f_file, &lock->fl);
if (error) {
/* We can't currently deal with deferred test requests */
@@ -548,6 +639,11 @@ nlmsvc_testlock(struct svc_rqst *rqstp, struct nlm_file *file,
conflock->fl.fl_start = lock->fl.fl_start;
conflock->fl.fl_end = lock->fl.fl_end;
locks_release_private(&lock->fl);
+
+ /* Clean up the test lock */
+ lock->fl.fl_owner = NULL;
+ nlmsvc_put_lockowner(test_owner);
+
ret = nlm_lck_denied;
out:
return ret;
diff --git a/fs/lockd/svcproc.c b/fs/lockd/svcproc.c
index ea77c66d3cc3..665b7adad3c4 100644
--- a/fs/lockd/svcproc.c
+++ b/fs/lockd/svcproc.c
@@ -76,8 +76,13 @@ nlmsvc_retrieve_args(struct svc_rqst *rqstp, struct nlm_args *argp,
/* Set up the missing parts of the file_lock structure */
lock->fl.fl_file = file->f_file;
- lock->fl.fl_owner = (fl_owner_t) host;
lock->fl.fl_lmops = &nlmsvc_lock_operations;
+ nlmsvc_locks_init_private(&lock->fl, host, (pid_t)lock->svid);
+ if (!lock->fl.fl_owner) {
+ /* lockowner allocation has failed */
+ nlmsvc_release_host(host);
+ return -ENOMEM;
+ }
}
return 0;
@@ -125,6 +130,7 @@ __nlmsvc_proc_test(struct svc_rqst *rqstp, struct nlm_res *resp)
dprintk("lockd: TEST status %d vers %d\n",
ntohl(resp->status), rqstp->rq_vers);
+ nlmsvc_release_lockowner(&argp->lock);
nlmsvc_release_host(host);
nlm_release_file(file);
return rc;
@@ -173,6 +179,7 @@ __nlmsvc_proc_lock(struct svc_rqst *rqstp, struct nlm_res *resp)
else
dprintk("lockd: LOCK status %d\n", ntohl(resp->status));
+ nlmsvc_release_lockowner(&argp->lock);
nlmsvc_release_host(host);
nlm_release_file(file);
return rc;
@@ -210,6 +217,7 @@ __nlmsvc_proc_cancel(struct svc_rqst *rqstp, struct nlm_res *resp)
resp->status = cast_status(nlmsvc_cancel_blocked(net, file, &argp->lock));
dprintk("lockd: CANCEL status %d\n", ntohl(resp->status));
+ nlmsvc_release_lockowner(&argp->lock);
nlmsvc_release_host(host);
nlm_release_file(file);
return rpc_success;
@@ -250,6 +258,7 @@ __nlmsvc_proc_unlock(struct svc_rqst *rqstp, struct nlm_res *resp)
resp->status = cast_status(nlmsvc_unlock(net, file, &argp->lock));
dprintk("lockd: UNLOCK status %d\n", ntohl(resp->status));
+ nlmsvc_release_lockowner(&argp->lock);
nlmsvc_release_host(host);
nlm_release_file(file);
return rpc_success;
@@ -408,6 +417,7 @@ nlmsvc_proc_share(struct svc_rqst *rqstp)
resp->status = cast_status(nlmsvc_share_file(host, file, argp));
dprintk("lockd: SHARE status %d\n", ntohl(resp->status));
+ nlmsvc_release_lockowner(&argp->lock);
nlmsvc_release_host(host);
nlm_release_file(file);
return rpc_success;
@@ -442,6 +452,7 @@ nlmsvc_proc_unshare(struct svc_rqst *rqstp)
resp->status = cast_status(nlmsvc_unshare_file(host, file, argp));
dprintk("lockd: UNSHARE status %d\n", ntohl(resp->status));
+ nlmsvc_release_lockowner(&argp->lock);
nlmsvc_release_host(host);
nlm_release_file(file);
return rpc_success;
diff --git a/fs/lockd/svcsubs.c b/fs/lockd/svcsubs.c
index 899360ba3b84..4ee04b725042 100644
--- a/fs/lockd/svcsubs.c
+++ b/fs/lockd/svcsubs.c
@@ -179,7 +179,7 @@ nlm_traverse_locks(struct nlm_host *host, struct nlm_file *file,
/* update current lock count */
file->f_locks++;
- lockhost = (struct nlm_host *) fl->fl_owner;
+ lockhost = ((struct nlm_lockowner *)fl->fl_owner)->host;
if (match(lockhost, host)) {
struct file_lock lock = *fl;
diff --git a/fs/lockd/xdr.c b/fs/lockd/xdr.c
index 7147e4aebecc..ec717ae41ee3 100644
--- a/fs/lockd/xdr.c
+++ b/fs/lockd/xdr.c
@@ -126,7 +126,6 @@ nlm_decode_lock(__be32 *p, struct nlm_lock *lock)
lock->svid = ntohl(*p++);
locks_init_lock(fl);
- fl->fl_owner = current->files;
fl->fl_pid = (pid_t)lock->svid;
fl->fl_flags = FL_POSIX;
fl->fl_type = F_RDLCK; /* as good as anything else */
diff --git a/fs/lockd/xdr4.c b/fs/lockd/xdr4.c
index 7ed9edf9aed4..45741adfe041 100644
--- a/fs/lockd/xdr4.c
+++ b/fs/lockd/xdr4.c
@@ -118,7 +118,6 @@ nlm4_decode_lock(__be32 *p, struct nlm_lock *lock)
lock->svid = ntohl(*p++);
locks_init_lock(fl);
- fl->fl_owner = current->files;
fl->fl_pid = (pid_t)lock->svid;
fl->fl_flags = FL_POSIX;
fl->fl_type = F_RDLCK; /* as good as anything else */
diff --git a/include/linux/lockd/lockd.h b/include/linux/lockd/lockd.h
index c9b422dde542..d294dde9e546 100644
--- a/include/linux/lockd/lockd.h
+++ b/include/linux/lockd/lockd.h
@@ -282,6 +282,7 @@ void nlmsvc_traverse_blocks(struct nlm_host *, struct nlm_file *,
nlm_host_match_fn_t match);
void nlmsvc_grant_reply(struct nlm_cookie *, __be32);
void nlmsvc_release_call(struct nlm_rqst *);
+void nlmsvc_locks_init_private(struct file_lock *, struct nlm_host *, pid_t);
/*
* File handling for the server personality
@@ -289,6 +290,7 @@ void nlmsvc_release_call(struct nlm_rqst *);
__be32 nlm_lookup_file(struct svc_rqst *, struct nlm_file **,
struct nfs_fh *);
void nlm_release_file(struct nlm_file *);
+void nlmsvc_release_lockowner(struct nlm_lock *);
void nlmsvc_mark_resources(struct net *);
void nlmsvc_free_host_resources(struct nlm_host *);
void nlmsvc_invalidate_all(void);
--
2.20.1
Now that the NLM server allocates an nlm_lockowner for fl_owner, there's
no need for special hashing or comparison.
Signed-off-by: Benjamin Coddington <[email protected]>
---
fs/lockd/svclock.c | 18 ------------------
1 file changed, 18 deletions(-)
diff --git a/fs/lockd/svclock.c b/fs/lockd/svclock.c
index 34c6ee85274e..637c50687fd7 100644
--- a/fs/lockd/svclock.c
+++ b/fs/lockd/svclock.c
@@ -788,25 +788,7 @@ nlmsvc_notify_blocked(struct file_lock *fl)
printk(KERN_WARNING "lockd: notification for unknown block!\n");
}
-static int nlmsvc_same_owner(struct file_lock *fl1, struct file_lock *fl2)
-{
- return fl1->fl_owner == fl2->fl_owner && fl1->fl_pid == fl2->fl_pid;
-}
-
-/*
- * Since NLM uses two "keys" for tracking locks, we need to hash them down
- * to one for the blocked_hash. Here, we're just xor'ing the host address
- * with the pid in order to create a key value for picking a hash bucket.
- */
-static unsigned long
-nlmsvc_owner_key(struct file_lock *fl)
-{
- return (unsigned long)fl->fl_owner ^ (unsigned long)fl->fl_pid;
-}
-
const struct lock_manager_operations nlmsvc_lock_operations = {
- .lm_compare_owner = nlmsvc_same_owner,
- .lm_owner_key = nlmsvc_owner_key,
.lm_notify = nlmsvc_notify_blocked,
.lm_grant = nlmsvc_grant_deferred,
};
--
2.20.1
On Thu, May 23, 2019 at 10:45:43AM -0400, Benjamin Coddington wrote:
> This series aims to correct the fl_pid value for locks held by the NLM
> server, or lockd. It applies onto the revert of the previous attempt to fix
> this problem sent ealier this week: '[PATCH] Revert "lockd: Show pid of
> lockd for remote locks"'.
>
> The problem with the earlier attempt was that we discarded the svid, and so
> we couldn't distinguish remote lockowners on each host. It is necessary to
> turn the svid and host into a distinct owner.
So, to make sure I understand, we've got multiple ways to identify a
lock owner:
- the svid, the pid of the client process: this gets returned to
the client in grant callbacks and (possibly to a different
client) in testd results.
- the pid of the server's lockd process: this is what other
processes on the server see as the owner of locks held by nfs
clients.
- the nlm_lockowner: a (nlm_host, svid) pair, used to actually
decide when locks conflict.
Makes sense to me.
I'll send your earlier revert to stable, then add this on top for the
5.3 merge window. Sound OK?
--b.
>
> We can take a page from the NLM client and make an allocation to track the
> svid and host together, which is what we do here. The mechanisms to do so
> aren't quite similar enough to generalize, but I did share the nlm_lockowner
> structure. There is one field unsed on the server: nlm_lockowner.owner.
>
> It turns out that the LTP's testcases/network/nfsv4/locks/locktests.c was
> useful for testing this, as it coordinates locking tests amongst NFS
> clients.
>
> Changes on:
> v2 - Fixed typos in commit log messages, and whitespace.
>
> Benjamin Coddington (5):
> lockd: prepare nlm_lockowner for use by the server
> lockd: Convert NLM service fl_owner to nlm_lockowner
> lockd: Remove lm_compare_owner and lm_owner_key
> lockd: Show pid of lockd for remote locks
> locks: Cleanup lm_compare_owner and lm_owner_key
>
> Documentation/filesystems/Locking | 14 ----
> fs/lockd/clntproc.c | 21 +++---
> fs/lockd/svc4proc.c | 14 +++-
> fs/lockd/svclock.c | 118 +++++++++++++++++++++++++-----
> fs/lockd/svcproc.c | 14 +++-
> fs/lockd/svcsubs.c | 2 +-
> fs/lockd/xdr.c | 3 -
> fs/lockd/xdr4.c | 3 -
> fs/locks.c | 5 --
> include/linux/fs.h | 2 -
> include/linux/lockd/lockd.h | 2 +
> 11 files changed, 138 insertions(+), 60 deletions(-)
>
> --
> 2.20.1
On 24 May 2019, at 12:47, J. Bruce Fields wrote:
> On Thu, May 23, 2019 at 10:45:43AM -0400, Benjamin Coddington wrote:
>> This series aims to correct the fl_pid value for locks held by the
>> NLM
>> server, or lockd. It applies onto the revert of the previous attempt
>> to fix
>> this problem sent ealier this week: '[PATCH] Revert "lockd: Show pid
>> of
>> lockd for remote locks"'.
>>
>> The problem with the earlier attempt was that we discarded the svid,
>> and so
>> we couldn't distinguish remote lockowners on each host. It is
>> necessary to
>> turn the svid and host into a distinct owner.
>
> So, to make sure I understand, we've got multiple ways to identify a
> lock owner:
>
> - the svid, the pid of the client process: this gets returned to
> the client in grant callbacks and (possibly to a different
> client) in testd results.
> - the pid of the server's lockd process: this is what other
> processes on the server see as the owner of locks held by nfs
> clients.
> - the nlm_lockowner: a (nlm_host, svid) pair, used to actually
> decide when locks conflict.
That's it.
> Makes sense to me.
>
> I'll send your earlier revert to stable, then add this on top for the
> 5.3 merge window. Sound OK?
Sounds great, thank you!
Ben