[CRIU] [PATCH 2/2] fsnotify: Warn a user if queued data present

[Andrew Vagin]

On Wed, Feb 26, 2014 at 01:36:41PM +0400, Cyrill Gorcunov wrote:
> At the moment we can't restore fsnotify queued data,
> so inform a user that some events are lost during
> c/r procedure.
> 
> Signed-off-by: Cyrill Gorcunov <gorcunov at openvz.org>
> ---
>  fsnotify.c | 21 +++++++++++++++++++++
>  1 file changed, 21 insertions(+)
> 
> diff --git a/fsnotify.c b/fsnotify.c
> index a81c2420bd34..08ada24324b2 100644
> --- a/fsnotify.c
> +++ b/fsnotify.c
> @@ -9,6 +9,7 @@
>  #include <utime.h>
>  #include <dirent.h>
>  #include <limits.h>
> +#include <poll.h>
>  #include <sys/stat.h>
>  #include <sys/types.h>
>  #include <sys/inotify.h>
> @@ -97,6 +98,19 @@ static void decode_handle(fh_t *handle, FhEntry *img)
>  				sizeof(handle->__handle)));
>  }
>  
> +static bool has_queued_events(int lfd)
> +{
> +	struct pollfd pfd = {lfd, POLLIN, 0};
> +	int ret;
> +
> +	ret = poll(&pfd, 1, 0);
> +	if (ret < 0)
> +		pr_perror("Poll request failed");
> +	else if (ret == 1)
> +		pr_warn("Has queued events to read\n");
> +	return ret != 0;
> +}
> +
>  static int open_handle(unsigned int s_dev, unsigned long i_ino,
>  		FhEntry *f_handle)
>  {
> @@ -204,6 +218,10 @@ static int dump_one_inotify(int lfd, u32 id, const struct fd_parms *p)
>  	ie.fown = (FownEntry *)&p->fown;
>  
>  	pr_info("id 0x%08x flags 0x%08x\n", ie.id, ie.flags);
> +
> +	if (has_queued_events(lfd) < 0)

has_queued_events returns true or false

> +		return -1;
> +
>  	if (pb_write_one(fdset_fd(glob_fdset, CR_FD_INOTIFY_FILE), &ie, PB_INOTIFY_FILE))
>  		return -1;
>  
> @@ -288,6 +306,9 @@ static int dump_one_fanotify(int lfd, u32 id, const struct fd_parms *p)
>  
>  	pr_info("id 0x%08x flags 0x%08x\n", fe.id, fe.flags);
>  
> +	if (has_queued_events(lfd) < 0)
> +		return -1;
> +
>  	fe.faflags = fsn_params.faflags;
>  	fe.evflags = fsn_params.evflags;
>  
> -- 
> 1.8.3.1
>