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lockd: save lock state on deferral
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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>
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Marc Eshel authored and J. Bruce Fields committed May 7, 2007
1 parent 2beb661 commit 2b36f41
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Showing 2 changed files with 35 additions and 0 deletions.
25 changes: 25 additions & 0 deletions fs/lockd/svclock.c
Original file line number Diff line number Diff line change
Expand Up @@ -330,6 +330,31 @@ static void nlmsvc_freegrantargs(struct nlm_rqst *call)
kfree(call->a_args.lock.oh.data);
}

/*
* 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.
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10 changes: 10 additions & 0 deletions include/linux/lockd/lockd.h
Original file line number Diff line number Diff line change
Expand Up @@ -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 */
Expand All @@ -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 */
};

/*
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