direct-io.hg
changeset 6947:2796d45c5835
Fire watches once immediately upon registration.
It matches the model of programming used to avoid races with watches,
and also makes re-establishing watches on daemon restart easier.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Christian Limpach <Christian.Limpach@cl.cam.ac.uk>
It matches the model of programming used to avoid races with watches,
and also makes re-establishing watches on daemon restart easier.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Christian Limpach <Christian.Limpach@cl.cam.ac.uk>
| author | cl349@firebug.cl.cam.ac.uk |
|---|---|
| date | Mon Sep 19 14:47:56 2005 +0000 (2005-09-19) |
| parents | 0a2cc72ee6e4 |
| children | fc2eade714f9 |
| files | linux-2.6-xen-sparse/drivers/xen/blkback/xenbus.c linux-2.6-xen-sparse/drivers/xen/blktap/xenbus.c linux-2.6-xen-sparse/drivers/xen/netback/xenbus.c linux-2.6-xen-sparse/drivers/xen/netfront/netfront.c linux-2.6-xen-sparse/drivers/xen/tpmback/xenbus.c linux-2.6-xen-sparse/drivers/xen/tpmfront/tpmfront.c tools/xenstore/testsuite/07watch.test tools/xenstore/testsuite/14complexperms.test tools/xenstore/xenstored_watch.c tools/xenstore/xs_test.c |
line diff
1.1 --- a/linux-2.6-xen-sparse/drivers/xen/blkback/xenbus.c Mon Sep 19 14:36:15 2005 +0000 1.2 +++ b/linux-2.6-xen-sparse/drivers/xen/blkback/xenbus.c Mon Sep 19 14:47:56 2005 +0000 1.3 @@ -228,6 +228,7 @@ static int blkback_probe(struct xenbus_d 1.4 be->dev = dev; 1.5 be->backend_watch.node = dev->nodename; 1.6 be->backend_watch.callback = backend_changed; 1.7 + /* Will implicitly call backend_changed once. */ 1.8 err = register_xenbus_watch(&be->backend_watch); 1.9 if (err) { 1.10 be->backend_watch.node = NULL; 1.11 @@ -249,8 +250,6 @@ static int blkback_probe(struct xenbus_d 1.12 } 1.13 1.14 dev->data = be; 1.15 - 1.16 - backend_changed(&be->backend_watch, dev->nodename); 1.17 return 0; 1.18 1.19 free_be:
2.1 --- a/linux-2.6-xen-sparse/drivers/xen/blktap/xenbus.c Mon Sep 19 14:36:15 2005 +0000 2.2 +++ b/linux-2.6-xen-sparse/drivers/xen/blktap/xenbus.c Mon Sep 19 14:47:56 2005 +0000 2.3 @@ -172,6 +172,7 @@ static int blkback_probe(struct xenbus_d 2.4 be->dev = dev; 2.5 be->backend_watch.node = dev->nodename; 2.6 be->backend_watch.callback = backend_changed; 2.7 + /* Registration implicitly fires backend_changed once */ 2.8 err = register_xenbus_watch(&be->backend_watch); 2.9 if (err) { 2.10 be->backend_watch.node = NULL; 2.11 @@ -193,8 +194,6 @@ static int blkback_probe(struct xenbus_d 2.12 } 2.13 2.14 dev->data = be; 2.15 - 2.16 - backend_changed(&be->backend_watch, dev->nodename); 2.17 return 0; 2.18 2.19 free_be:
3.1 --- a/linux-2.6-xen-sparse/drivers/xen/netback/xenbus.c Mon Sep 19 14:36:15 2005 +0000 3.2 +++ b/linux-2.6-xen-sparse/drivers/xen/netback/xenbus.c Mon Sep 19 14:47:56 2005 +0000 3.3 @@ -242,6 +242,7 @@ static int netback_probe(struct xenbus_d 3.4 be->dev = dev; 3.5 be->backend_watch.node = dev->nodename; 3.6 be->backend_watch.callback = backend_changed; 3.7 + /* Registration implicitly calls backend_changed. */ 3.8 err = register_xenbus_watch(&be->backend_watch); 3.9 if (err) { 3.10 be->backend_watch.node = NULL; 3.11 @@ -263,8 +264,6 @@ static int netback_probe(struct xenbus_d 3.12 } 3.13 3.14 dev->data = be; 3.15 - 3.16 - backend_changed(&be->backend_watch, dev->nodename); 3.17 return 0; 3.18 3.19 free_be:
4.1 --- a/linux-2.6-xen-sparse/drivers/xen/netfront/netfront.c Mon Sep 19 14:36:15 2005 +0000 4.2 +++ b/linux-2.6-xen-sparse/drivers/xen/netfront/netfront.c Mon Sep 19 14:47:56 2005 +0000 4.3 @@ -1284,10 +1284,6 @@ static int netfront_probe(struct xenbus_ 4.4 return err; 4.5 } 4.6 4.7 - 4.8 - /* Call once in case entries already there. */ 4.9 - watch_for_status(&info->watch, info->watch.node); 4.10 - 4.11 return 0; 4.12 } 4.13
5.1 --- a/linux-2.6-xen-sparse/drivers/xen/tpmback/xenbus.c Mon Sep 19 14:36:15 2005 +0000 5.2 +++ b/linux-2.6-xen-sparse/drivers/xen/tpmback/xenbus.c Mon Sep 19 14:47:56 2005 +0000 5.3 @@ -213,6 +213,7 @@ static int tpmback_probe(struct xenbus_d 5.4 5.5 be->dev = dev; 5.6 be->backend_watch.node = dev->nodename; 5.7 + /* Implicitly calls backend_changed() once. */ 5.8 be->backend_watch.callback = backend_changed; 5.9 be->instance = -1; 5.10 err = register_xenbus_watch(&be->backend_watch); 5.11 @@ -236,8 +237,6 @@ static int tpmback_probe(struct xenbus_d 5.12 } 5.13 5.14 dev->data = be; 5.15 - 5.16 - backend_changed(&be->backend_watch, dev->nodename); 5.17 return err; 5.18 5.19 free_be:
6.1 --- a/linux-2.6-xen-sparse/drivers/xen/tpmfront/tpmfront.c Mon Sep 19 14:36:15 2005 +0000 6.2 +++ b/linux-2.6-xen-sparse/drivers/xen/tpmfront/tpmfront.c Mon Sep 19 14:47:56 2005 +0000 6.3 @@ -411,7 +411,6 @@ static int tpmfront_probe(struct xenbus_ 6.4 return err; 6.5 } 6.6 6.7 - watch_for_status(&info->watch, info->watch.node); 6.8 return 0; 6.9 } 6.10
7.1 --- a/tools/xenstore/testsuite/07watch.test Mon Sep 19 14:36:15 2005 +0000 7.2 +++ b/tools/xenstore/testsuite/07watch.test Mon Sep 19 14:47:56 2005 +0000 7.3 @@ -168,10 +168,12 @@ 1 close 7.4 # Watch event must have happened before we registered interest. 7.5 1 watch / token 7.6 2 write /test/subnode contents2 7.7 -1 watch / token2 0 7.8 +1 watchnoack / token2 0 7.9 expect 1:/test/subnode:token 7.10 1 waitwatch 7.11 1 ackwatch token 7.12 +expect 1:/:token2 7.13 +1 waitwatch 7.14 expect 1: waitwatch failed: Connection timed out 7.15 1 waitwatch 7.16 1 close
8.1 --- a/tools/xenstore/testsuite/14complexperms.test Mon Sep 19 14:36:15 2005 +0000 8.2 +++ b/tools/xenstore/testsuite/14complexperms.test Mon Sep 19 14:47:56 2005 +0000 8.3 @@ -23,7 +23,8 @@ expect *Permission denied 8.4 getperm /dir/file 8.5 expect *Permission denied 8.6 setperm /dir/file 0 NONE 8.7 -watch /dir/file token 8.8 +# We get no watch event when there's no permission. It's a corner case. 8.9 +watchnoack /dir/file token 8.10 1 write /dir/file contents 8.11 1 rm /dir/file 8.12 expect waitwatch failed: Connection timed out 8.13 @@ -63,7 +64,7 @@ expect *Permission denied 8.14 getperm /dir/file 8.15 expect *Permission denied 8.16 setperm /dir/file 0 NONE 8.17 -watch /dir/file token 8.18 +watchnoack /dir/file token 8.19 1 write /dir/file contents 8.20 1 rm /dir/file 8.21 expect waitwatch failed: Connection timed out
9.1 --- a/tools/xenstore/xenstored_watch.c Mon Sep 19 14:36:15 2005 +0000 9.2 +++ b/tools/xenstore/xenstored_watch.c Mon Sep 19 14:47:56 2005 +0000 9.3 @@ -236,6 +236,9 @@ void do_watch(struct connection *conn, s 9.4 trace_create(watch, "watch"); 9.5 talloc_set_destructor(watch, destroy_watch); 9.6 send_ack(conn, XS_WATCH); 9.7 + 9.8 + /* We fire once up front: simplifies clients and restart. */ 9.9 + add_event(conn, watch, watch->node); 9.10 } 9.11 9.12 void do_watch_ack(struct connection *conn, const char *token)
10.1 --- a/tools/xenstore/xs_test.c Mon Sep 19 14:36:15 2005 +0000 10.2 +++ b/tools/xenstore/xs_test.c Mon Sep 19 14:47:56 2005 +0000 10.3 @@ -200,6 +200,7 @@ static void __attribute__((noreturn)) us 10.4 " setperm <path> <id> <flags> ...\n" 10.5 " shutdown\n" 10.6 " watch <path> <token>\n" 10.7 + " watchnoack <path> <token>\n" 10.8 " waitwatch\n" 10.9 " ackwatch <token>\n" 10.10 " unwatch <path> <token>\n" 10.11 @@ -480,10 +481,20 @@ static void do_shutdown(unsigned int han 10.12 failed(handle); 10.13 } 10.14 10.15 -static void do_watch(unsigned int handle, const char *node, const char *token) 10.16 +static void do_watch(unsigned int handle, const char *node, const char *token, 10.17 + bool swallow_event) 10.18 { 10.19 if (!xs_watch(handles[handle], node, token)) 10.20 failed(handle); 10.21 + 10.22 + /* Convenient for testing... */ 10.23 + if (swallow_event) { 10.24 + char **vec = xs_read_watch(handles[handle]); 10.25 + if (!vec || !streq(vec[0], node) || !streq(vec[1], token)) 10.26 + failed(handle); 10.27 + if (!xs_acknowledge_watch(handles[handle], token)) 10.28 + failed(handle); 10.29 + } 10.30 } 10.31 10.32 static void set_timeout(void) 10.33 @@ -767,7 +778,9 @@ static void do_command(unsigned int defa 10.34 else if (streq(command, "shutdown")) 10.35 do_shutdown(handle); 10.36 else if (streq(command, "watch")) 10.37 - do_watch(handle, arg(line, 1), arg(line, 2)); 10.38 + do_watch(handle, arg(line, 1), arg(line, 2), true); 10.39 + else if (streq(command, "watchnoack")) 10.40 + do_watch(handle, arg(line, 1), arg(line, 2), false); 10.41 else if (streq(command, "waitwatch")) 10.42 do_waitwatch(handle); 10.43 else if (streq(command, "ackwatch"))