From: Marc Eshel <eshel@xxxxxxxxxxxxxxx> - unquoted
We need to keep some state for a pending asynchronous lock request, so this
patch adds that state to struct nlm_block.
This also adds a function which defers the request, by calling
rqstp->rq_chandle.defer and storing the resulting deferred request in a
nlm_block structure which we insert into lockd's global block list. That
new function isn't called yet, so it's dead code until a later patch.
Signed-off-by: Marc Eshel <eshel@xxxxxxxxxxxxxxx>
Signed-off-by: J. Bruce Fields <bfields@xxxxxxxxxxxxxx>
---
fs/lockd/svclock.c | 25 +++++++++++++++++++++++++
include/linux/lockd/lockd.h | 10 ++++++++++
2 files changed, 35 insertions(+), 0 deletions(-)
diff --git a/fs/lockd/svclock.c b/fs/lockd/svclock.c
index d2c8020..00e657a 100644
--- a/fs/lockd/svclock.c
+++ b/fs/lockd/svclock.c
@@ -331,6 +331,31 @@ static void nlmsvc_freegrantargs(struct nlm_rqst *call)
}
/*
+ * Deferred lock request handling for non-blocking lock
+ */
+static u32
+nlmsvc_defer_lock_rqst(struct svc_rqst *rqstp, struct nlm_block *block)
+{
+ u32 status = nlm_lck_denied_nolocks;
+
+ block->b_flags |= B_QUEUED;
+
+ nlmsvc_insert_block(block, NLM_TIMEOUT);
+
+ block->b_cache_req = &rqstp->rq_chandle;
+ if (rqstp->rq_chandle.defer) {
+ block->b_deferred_req =
+ rqstp->rq_chandle.defer(block->b_cache_req);
+ if (block->b_deferred_req != NULL)
+ status = nlm_drop_reply;
+ }
+ dprintk("lockd: nlmsvc_defer_lock_rqst block %p flags %d status %d\n",
+ block, block->b_flags, status);
+
+ return status;
+}
+
+/*
* Attempt to establish a lock, and if it can't be granted, block it
* if required.
*/
diff --git a/include/linux/lockd/lockd.h b/include/linux/lockd/lockd.h
index ac25b56..1df10d7 100644
--- a/include/linux/lockd/lockd.h
+++ b/include/linux/lockd/lockd.h
@@ -119,6 +119,9 @@ struct nlm_file {
* couldn't be granted because of a conflicting lock).
*/
#define NLM_NEVER (~(unsigned long) 0)
+/* timeout on non-blocking call: */
+#define NLM_TIMEOUT (7 * HZ)
+
struct nlm_block {
struct kref b_count; /* Reference count */
struct list_head b_list; /* linked list of all blocks */
@@ -130,6 +133,13 @@ struct nlm_block {
unsigned int b_id; /* block id */
unsigned char b_granted; /* VFS granted lock */
struct nlm_file * b_file; /* file in question */
+ struct cache_req * b_cache_req; /* deferred request handling */
+ struct file_lock * b_fl; /* set for GETLK */
+ struct cache_deferred_req * b_deferred_req;
+ unsigned int b_flags; /* block flags */
+#define B_QUEUED 1 /* lock queued */
+#define B_GOT_CALLBACK 2 /* got lock or conflicting lock */
+#define B_TOO_LATE 4 /* too late for non-blocking lock */
};
/*
--
1.5.0.rc1.g72fe
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