lockd: save lock state on deferral

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@almaden.ibm.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

diff --git a/fs/lockd/svclock.c b/fs/lockd/svclock.c
index 3b0e7a4..f244926 100644 (file)
--- 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..d4c4de7 100644 (file)
--- 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_TIMED_OUT            4       /* filesystem too slow to respond */
 };
 
 /*