[PATCH v2] http: update in-memory devXX/usage on PUT+DELETE

[Eric Wong <e@80x24.org>]

Under heavy write traffic, free space changes constantly, and
the periodic updates every 10 (or MOG_DISK_USAGE_INTERVAL)
seconds can be too far behind.  Since we keep the usage file
contents in-memory now for out-of-FD situations, we can update
that without incurring extra VFS traffic.

v2: We no longer try to use fstatvfs(2) and instead pay the cost of
an extra name lookups and just update all usage files.  This was
necessary since calculating free space while a file is still
open can take a long time on some FSes and we need to send the
HTTP response back ASAP to avoid timeouts on the client-side.

This avoids contention in the request worker threads and the
mostly idle main thread to do more work.
---
 http_dav.c | 2 ++
 http_put.c | 1 +
 2 files changed, 3 insertions(+)

diff --git a/http_dav.c b/http_dav.c
index 4b6df9b..43b6c7a 100644
--- a/http_dav.c
+++ b/http_dav.c
@@ -29,6 +29,8 @@ void mog_http_delete(struct mog_fd *mfd, char *buf)
 	rc = mog_unlink(http->svc, path);
 	if (rc == 0) {
 		mog_http_resp(mfd, "204 No Content", true);
+		mog_notify(MOG_NOTIFY_DEVICE_REFRESH);
+
 		return;
 	}
 
diff --git a/http_put.c b/http_put.c
index fc36ba7..11d6342 100644
--- a/http_put.c
+++ b/http_put.c
@@ -153,6 +153,7 @@ static void put_commit_resp(struct mog_fd *mfd)
 		if (set_perms_commit(http)) {
 			file_close_null(mfd);
 			mog_http_resp(mfd, "201 Created", true);
+			mog_notify(MOG_NOTIFY_DEVICE_REFRESH);
 		} else {
 			file_close_null(mfd);
 			mog_http_resp(mfd, "500 Internal Server Error", false);