diff options
author | Trond Myklebust <Trond.Myklebust@netapp.com> | 2005-06-22 17:16:31 +0000 |
---|---|---|
committer | Trond Myklebust <Trond.Myklebust@netapp.com> | 2005-06-22 16:07:42 -0400 |
commit | ecdbf769b2cb8903e07cd482334c714d89fd1146 (patch) | |
tree | 9d02ce4daee662c2711762564662cebc521e3da3 /fs/lockd/clntproc.c | |
parent | 4f15e2b1f4f3a56e46201714b39436c32218d547 (diff) |
[PATCH] NLM: fix a client-side race on blocking locks.
If the lock blocks, the server may send us a GRANTED message that
races with the reply to our LOCK request. Make sure that we catch
the GRANTED by queueing up our request on the nlm_blocked list
before we send off the first LOCK rpc call.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Diffstat (limited to 'fs/lockd/clntproc.c')
-rw-r--r-- | fs/lockd/clntproc.c | 40 |
1 files changed, 32 insertions, 8 deletions
diff --git a/fs/lockd/clntproc.c b/fs/lockd/clntproc.c index a4407619b1f1..fd77ed1d710d 100644 --- a/fs/lockd/clntproc.c +++ b/fs/lockd/clntproc.c @@ -21,6 +21,7 @@ #define NLMDBG_FACILITY NLMDBG_CLIENT #define NLMCLNT_GRACE_WAIT (5*HZ) +#define NLMCLNT_POLL_TIMEOUT (30*HZ) static int nlmclnt_test(struct nlm_rqst *, struct file_lock *); static int nlmclnt_lock(struct nlm_rqst *, struct file_lock *); @@ -553,7 +554,8 @@ nlmclnt_lock(struct nlm_rqst *req, struct file_lock *fl) { struct nlm_host *host = req->a_host; struct nlm_res *resp = &req->a_res; - int status; + long timeout; + int status; if (!host->h_monitored && nsm_monitor(host) < 0) { printk(KERN_NOTICE "lockd: failed to monitor %s\n", @@ -562,15 +564,32 @@ nlmclnt_lock(struct nlm_rqst *req, struct file_lock *fl) goto out; } - do { - if ((status = nlmclnt_call(req, NLMPROC_LOCK)) >= 0) { - if (resp->status != NLM_LCK_BLOCKED) - break; - status = nlmclnt_block(host, fl, &resp->status); - } + if (req->a_args.block) { + status = nlmclnt_prepare_block(req, host, fl); if (status < 0) goto out; - } while (resp->status == NLM_LCK_BLOCKED && req->a_args.block); + } + for(;;) { + status = nlmclnt_call(req, NLMPROC_LOCK); + if (status < 0) + goto out_unblock; + if (resp->status != NLM_LCK_BLOCKED) + break; + /* Wait on an NLM blocking lock */ + timeout = nlmclnt_block(req, NLMCLNT_POLL_TIMEOUT); + /* Did a reclaimer thread notify us of a server reboot? */ + if (resp->status == NLM_LCK_DENIED_GRACE_PERIOD) + continue; + if (resp->status != NLM_LCK_BLOCKED) + break; + if (timeout >= 0) + continue; + /* We were interrupted. Send a CANCEL request to the server + * and exit + */ + status = (int)timeout; + goto out_unblock; + } if (resp->status == NLM_LCK_GRANTED) { fl->fl_u.nfs_fl.state = host->h_state; @@ -579,6 +598,11 @@ nlmclnt_lock(struct nlm_rqst *req, struct file_lock *fl) do_vfs_lock(fl); } status = nlm_stat_to_errno(resp->status); +out_unblock: + nlmclnt_finish_block(req); + /* Cancel the blocked request if it is still pending */ + if (resp->status == NLM_LCK_BLOCKED) + nlmclnt_cancel(host, fl); out: nlmclnt_release_lockargs(req); return status; |