lockd: handle test_lock deferrals
Rewrite nlmsvc_testlock() to use the new asynchronous interface: instead of
immediately doing a posix_test_lock(), we first look for a matching block.
If the subsequent test_lock returns anything other than -EINPROGRESS, we
then remove the block we've found and return the results.
If it returns -EINPROGRESS, then we defer the lock request.
In the case where the block we find in the first step has B_QUEUED set,
we bypass the vfs_test_lock entirely, instead using the block to decide how
to respond:
with nlm_lck_denied if B_TIMED_OUT is set.
with nlm_granted if B_GOT_CALLBACK is set.
by dropping if neither B_TIMED_OUT nor B_GOT_CALLBACK is set
Signed-off-by: Marc Eshel <eshel@almaden.ibm.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
diff --git a/fs/lockd/svc4proc.c b/fs/lockd/svc4proc.c
index a1bccad..205d8be 100644
--- a/fs/lockd/svc4proc.c
+++ b/fs/lockd/svc4proc.c
@@ -100,6 +100,8 @@
/* Now check for conflicting locks */
resp->status = nlmsvc_testlock(rqstp, file, &argp->lock, &resp->lock, &resp->cookie);
+ if (resp->status == nlm_drop_reply)
+ return rpc_drop_reply;
dprintk("lockd: TEST4 status %d\n", ntohl(resp->status));
nlm_release_host(host);
diff --git a/fs/lockd/svclock.c b/fs/lockd/svclock.c
index 7ab2e60..b7a8174 100644
--- a/fs/lockd/svclock.c
+++ b/fs/lockd/svclock.c
@@ -173,7 +173,7 @@
*/
static inline struct nlm_block *
nlmsvc_create_block(struct svc_rqst *rqstp, struct nlm_file *file,
- struct nlm_lock *lock, struct nlm_cookie *cookie)
+ struct nlm_lock *lock, struct nlm_cookie *cookie)
{
struct nlm_block *block;
struct nlm_host *host;
@@ -210,6 +210,7 @@
block->b_daemon = rqstp->rq_server;
block->b_host = host;
block->b_file = file;
+ block->b_fl = NULL;
file->f_count++;
/* Add to file's list of blocks */
@@ -446,6 +447,10 @@
struct nlm_lock *lock, struct nlm_lock *conflock,
struct nlm_cookie *cookie)
{
+ struct nlm_block *block = NULL;
+ int error;
+ __be32 ret;
+
dprintk("lockd: nlmsvc_testlock(%s/%ld, ty=%d, %Ld-%Ld)\n",
file->f_file->f_path.dentry->d_inode->i_sb->s_id,
file->f_file->f_path.dentry->d_inode->i_ino,
@@ -453,22 +458,70 @@
(long long)lock->fl.fl_start,
(long long)lock->fl.fl_end);
- if (posix_test_lock(file->f_file, &lock->fl)) {
- dprintk("lockd: conflicting lock(ty=%d, %Ld-%Ld)\n",
- lock->fl.fl_type,
- (long long)lock->fl.fl_start,
- (long long)lock->fl.fl_end);
- conflock->caller = "somehost"; /* FIXME */
- conflock->len = strlen(conflock->caller);
- conflock->oh.len = 0; /* don't return OH info */
- conflock->svid = lock->fl.fl_pid;
- conflock->fl.fl_type = lock->fl.fl_type;
- conflock->fl.fl_start = lock->fl.fl_start;
- conflock->fl.fl_end = lock->fl.fl_end;
- return nlm_lck_denied;
+ /* Get existing block (in case client is busy-waiting) */
+ block = nlmsvc_lookup_block(file, lock);
+
+ if (block == NULL) {
+ struct file_lock *conf = kzalloc(sizeof(*conf), GFP_KERNEL);
+
+ if (conf == NULL)
+ return nlm_granted;
+ block = nlmsvc_create_block(rqstp, file, lock, cookie);
+ if (block == NULL) {
+ kfree(conf);
+ return nlm_granted;
+ }
+ block->b_fl = conf;
+ }
+ if (block->b_flags & B_QUEUED) {
+ dprintk("lockd: nlmsvc_testlock deferred block %p flags %d fl %p\n",
+ block, block->b_flags, block->b_fl);
+ if (block->b_flags & B_TIMED_OUT) {
+ nlmsvc_unlink_block(block);
+ return nlm_lck_denied;
+ }
+ if (block->b_flags & B_GOT_CALLBACK) {
+ if (block->b_fl != NULL
+ && block->b_fl->fl_type != F_UNLCK) {
+ lock->fl = *block->b_fl;
+ goto conf_lock;
+ }
+ else {
+ nlmsvc_unlink_block(block);
+ return nlm_granted;
+ }
+ }
+ return nlm_drop_reply;
}
- return nlm_granted;
+ error = vfs_test_lock(file->f_file, &lock->fl);
+ if (error == -EINPROGRESS)
+ return nlmsvc_defer_lock_rqst(rqstp, block);
+ if (error) {
+ ret = nlm_lck_denied_nolocks;
+ goto out;
+ }
+ if (lock->fl.fl_type == F_UNLCK) {
+ ret = nlm_granted;
+ goto out;
+ }
+
+conf_lock:
+ dprintk("lockd: conflicting lock(ty=%d, %Ld-%Ld)\n",
+ lock->fl.fl_type, (long long)lock->fl.fl_start,
+ (long long)lock->fl.fl_end);
+ conflock->caller = "somehost"; /* FIXME */
+ conflock->len = strlen(conflock->caller);
+ conflock->oh.len = 0; /* don't return OH info */
+ conflock->svid = lock->fl.fl_pid;
+ conflock->fl.fl_type = lock->fl.fl_type;
+ conflock->fl.fl_start = lock->fl.fl_start;
+ conflock->fl.fl_end = lock->fl.fl_end;
+ ret = nlm_lck_denied;
+out:
+ if (block)
+ nlmsvc_release_block(block);
+ return ret;
}
/*
@@ -549,7 +602,6 @@
else
block->b_flags |= B_TIMED_OUT;
if (conf) {
- block->b_fl = kzalloc(sizeof(struct file_lock), GFP_KERNEL);
if (block->b_fl)
locks_copy_lock(block->b_fl, conf);
}
diff --git a/fs/lockd/svcproc.c b/fs/lockd/svcproc.c
index d13b827..40b5cf4 100644
--- a/fs/lockd/svcproc.c
+++ b/fs/lockd/svcproc.c
@@ -33,6 +33,7 @@
case nlm_lck_denied_nolocks:
case nlm_lck_blocked:
case nlm_lck_denied_grace_period:
+ case nlm_drop_reply:
break;
case nlm4_deadlock:
status = nlm_lck_denied;
@@ -128,6 +129,8 @@
/* Now check for conflicting locks */
resp->status = cast_status(nlmsvc_testlock(rqstp, file, &argp->lock, &resp->lock, &resp->cookie));
+ if (resp->status == nlm_drop_reply)
+ return rpc_drop_reply;
dprintk("lockd: TEST status %d vers %d\n",
ntohl(resp->status), rqstp->rq_vers);
