2007-02-03 05:34:09

by J.Bruce Fields

[permalink] [raw]
Subject: [PATCH 13/14] lockd: add code to handle deferred lock requests

From: Marc Eshel <[email protected]> - unquoted

Rewrite nlmsvc_lock() to use the asynchronous interface.

As with testlock, we answer nlm requests in nlmsvc_lock by first looking up
the block and then using the results we find in the block if B_QUEUED is
set, and calling vfs_lock_file() otherwise.

If this a new lock request and we get -EINPROGRESS return on a non-blocking
request then we defer the request.

Also modify nlmsvc_unlock() to call the filesystem method if appropriate.

Signed-off-by: Marc Eshel <[email protected]>
Signed-off-by: J. Bruce Fields <[email protected]>
---
fs/lockd/svclock.c | 40 ++++++++++++++++++++++++++++++++++------
fs/lockd/svcsubs.c | 2 +-
2 files changed, 35 insertions(+), 7 deletions(-)

diff --git a/fs/lockd/svclock.c b/fs/lockd/svclock.c
index 32202fa..61137b6 100644
--- a/fs/lockd/svclock.c
+++ b/fs/lockd/svclock.c
@@ -393,17 +393,44 @@ nlmsvc_lock(struct svc_rqst *rqstp, struct nlm_file *file,
} else
lock->fl.fl_flags &= ~FL_SLEEP;

- error = posix_lock_file(file->f_file, &lock->fl);
- lock->fl.fl_flags &= ~FL_SLEEP;

- dprintk("lockd: posix_lock_file returned %d\n", error);
+ if (block->b_flags & B_QUEUED) {
+ dprintk("lockd: nlmsvc_lock deferred block %p flags %d\n",
+ block, block->b_flags);
+ if (block->b_granted) {
+ nlmsvc_unlink_block(block);
+ ret = nlm_granted;
+ goto out;
+ }
+ if (block->b_flags & B_TOO_LATE) {
+ nlmsvc_unlink_block(block);
+ ret = nlm_lck_denied;
+ goto out;
+ }
+ ret = nlm_drop_reply;
+ goto out;
+ }

+ if (!wait)
+ lock->fl.fl_flags &= ~FL_SLEEP;
+ error = vfs_lock_file(file->f_file, F_SETLK, &lock->fl);
+ lock->fl.fl_flags &= ~FL_SLEEP;
+
+ dprintk("lockd: vfs_lock_file returned %d\n", error);
switch(error) {
case 0:
ret = nlm_granted;
goto out;
case -EAGAIN:
+ ret = nlm_lck_denied;
break;
+ case -EINPROGRESS:
+ if (wait)
+ break;
+ /* Filesystem lock operation is in progress
+ Add it to the queue waiting for callback */
+ ret = nlmsvc_defer_lock_rqst(rqstp, block);
+ goto out;
case -EDEADLK:
ret = nlm_deadlock;
goto out;
@@ -519,7 +546,7 @@ nlmsvc_unlock(struct nlm_file *file, struct nlm_lock *lock)
nlmsvc_cancel_blocked(file, lock);

lock->fl.fl_type = F_UNLCK;
- error = posix_lock_file(file->f_file, &lock->fl);
+ error = vfs_lock_file(file->f_file, F_SETLK, &lock->fl);

return (error < 0)? nlm_lck_denied_nolocks : nlm_granted;
}
@@ -665,14 +692,15 @@ nlmsvc_grant_blocked(struct nlm_block *block)

/* Try the lock operation again */
lock->fl.fl_flags |= FL_SLEEP;
- error = posix_lock_file(file->f_file, &lock->fl);
+ error = vfs_lock_file(file->f_file, F_SETLK, &lock->fl);
lock->fl.fl_flags &= ~FL_SLEEP;

switch (error) {
case 0:
break;
case -EAGAIN:
- dprintk("lockd: lock still blocked\n");
+ case -EINPROGRESS:
+ dprintk("lockd: lock still blocked error %d\n", error);
nlmsvc_insert_block(block, NLM_NEVER);
nlmsvc_release_block(block);
return;
diff --git a/fs/lockd/svcsubs.c b/fs/lockd/svcsubs.c
index c0df00c..cede998 100644
--- a/fs/lockd/svcsubs.c
+++ b/fs/lockd/svcsubs.c
@@ -182,7 +182,7 @@ again:
lock.fl_type = F_UNLCK;
lock.fl_start = 0;
lock.fl_end = OFFSET_MAX;
- if (posix_lock_file(file->f_file, &lock) < 0) {
+ if (vfs_lock_file(file->f_file, F_SETLK, &lock) < 0) {
printk("lockd: unlock failure in %s:%d\n",
__FILE__, __LINE__);
return 1;
--
1.5.0.rc1.g72fe