On Thu, Oct 13, 2011 at 04:56:43PM +0800, boyd yang wrote:
> This patch fixes a hang problem of Eric Paris's fs Notification/fanotify.
>
> Fanotify brings a way to intercept file access events.
> When multiple threadsiterate the same direcotry, some thread will hang.
> This patch let fanotify to differ access events from different
> threads, prevent fanotify from merging access events from different
> threads.
>
You need to run this through checkpatch.pl, you have a ton of formatting
problems. Also your email client seems to have word-wrapped parts of this, so
use a email client that doesn't word wrap.
> =============================================================
>
> diff -r -u linux-3.1-rc4_orig/fs/notify/fanotify/fanotify.c
> linux-3.1-rc4/fs/notify/fanotify/fanotify.c
> --- linux-3.1-rc4_orig/fs/notify/fanotify/fanotify.c 2011-08-29
> 12:16:01.000000000 +0800
> +++ linux-3.1-rc4/fs/notify/fanotify/fanotify.c 2011-10-10
> 12:28:23.276847000 +0800
> @@ -15,7 +15,8 @@
>
> if (old->to_tell == new->to_tell &&
> old->data_type == new->data_type &&
> - old->tgid == new->tgid) {
> + old->tgid == new->tgid &&
> + old->pid == new->pid) {
> switch (old->data_type) {
> case (FSNOTIFY_EVENT_PATH):
> if ((old->path.mnt == new->path.mnt) &&
> @@ -144,11 +145,19 @@
> return PTR_ERR(notify_event);
>
> #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS
> - if (event->mask & FAN_ALL_PERM_EVENTS) {
> - /* if we merged we need to wait on the new event */
> - if (notify_event)
> - event = notify_event;
> - ret = fanotify_get_response_from_access(group, event);
> + //if overflow, do not wait for response
> + if(fsnotify_isoverflow(event))
> + {
> + pr_debug("fanotify overflow!\n");
> + }
> + else
> + {
> + if (event->mask & FAN_ALL_PERM_EVENTS) {
> + /* if we merged we need to wait on the new event */
> + if (notify_event)
> + event = notify_event;
> + ret = fanotify_get_response_from_access(group, event);
> + }
> }
The overflow event should only have FS_Q_OVERFLOW set in it's mask right? So
why is this test needed at all? Thanks,
Josef
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