diff mbox series

[054/104] virtiofsd: set maximum RLIMIT_NOFILE limit

Message ID 20191212163904.159893-55-dgilbert@redhat.com
State New
Headers show
Series virtiofs daemon [all] | expand

Commit Message

Dr. David Alan Gilbert Dec. 12, 2019, 4:38 p.m. UTC 
From: Stefan Hajnoczi <stefanha@redhat.com>

virtiofsd can exceed the default open file descriptor limit easily on
most systems.  Take advantage of the fact that it runs as root to raise
the limit.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 tools/virtiofsd/passthrough_ll.c | 32 ++++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)

Comments

Daniel P. Berrangé Jan. 6, 2020, 3 p.m. UTC | #1 
On Thu, Dec 12, 2019 at 04:38:14PM +0000, Dr. David Alan Gilbert (git) wrote:
> From: Stefan Hajnoczi <stefanha@redhat.com>
> 
> virtiofsd can exceed the default open file descriptor limit easily on
> most systems.  Take advantage of the fact that it runs as root to raise
> the limit.
> 
> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
> ---
>  tools/virtiofsd/passthrough_ll.c | 32 ++++++++++++++++++++++++++++++++
>  1 file changed, 32 insertions(+)

Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>


Regards,
Daniel
Philippe Mathieu-Daudé Jan. 15, 2020, 5:09 p.m. UTC | #2 
On 12/12/19 5:38 PM, Dr. David Alan Gilbert (git) wrote:
> From: Stefan Hajnoczi <stefanha@redhat.com>
> 
> virtiofsd can exceed the default open file descriptor limit easily on
> most systems.  Take advantage of the fact that it runs as root to raise
> the limit.
> 
> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
> ---
>   tools/virtiofsd/passthrough_ll.c | 32 ++++++++++++++++++++++++++++++++
>   1 file changed, 32 insertions(+)
> 
> diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthrough_ll.c
> index ab318a6f36..139bf08f4c 100644
> --- a/tools/virtiofsd/passthrough_ll.c
> +++ b/tools/virtiofsd/passthrough_ll.c
> @@ -52,6 +52,7 @@
>   #include <sys/file.h>
>   #include <sys/mount.h>
>   #include <sys/prctl.h>
> +#include <sys/resource.h>
>   #include <sys/syscall.h>
>   #include <sys/types.h>
>   #include <sys/wait.h>
> @@ -2250,6 +2251,35 @@ static void setup_sandbox(struct lo_data *lo, struct fuse_session *se)
>       setup_seccomp();
>   }
>   
> +/* Raise the maximum number of open file descriptors */
> +static void setup_nofile_rlimit(void)
> +{
> +    const rlim_t max_fds = 1000000;

'static const'?

Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>

> +    struct rlimit rlim;
> +
> +    if (getrlimit(RLIMIT_NOFILE, &rlim) < 0) {
> +        fuse_log(FUSE_LOG_ERR, "getrlimit(RLIMIT_NOFILE): %m\n");
> +        exit(1);
> +    }
> +
> +    if (rlim.rlim_cur >= max_fds) {
> +        return; /* nothing to do */
> +    }
> +
> +    rlim.rlim_cur = max_fds;
> +    rlim.rlim_max = max_fds;
> +
> +    if (setrlimit(RLIMIT_NOFILE, &rlim) < 0) {
> +        /* Ignore SELinux denials */
> +        if (errno == EPERM) {
> +            return;
> +        }
> +
> +        fuse_log(FUSE_LOG_ERR, "setrlimit(RLIMIT_NOFILE): %m\n");
> +        exit(1);
> +    }
> +}
> +
>   int main(int argc, char *argv[])
>   {
>       struct fuse_args args = FUSE_ARGS_INIT(argc, argv);
> @@ -2371,6 +2401,8 @@ int main(int argc, char *argv[])
>   
>       fuse_daemonize(opts.foreground);
>   
> +    setup_nofile_rlimit();
> +
>       /* Must be before sandbox since it wants /proc */
>       setup_capng();
>   
>
Dr. David Alan Gilbert Jan. 15, 2020, 5:38 p.m. UTC | #3 
* Philippe Mathieu-Daudé (philmd@redhat.com) wrote:
> On 12/12/19 5:38 PM, Dr. David Alan Gilbert (git) wrote:
> > From: Stefan Hajnoczi <stefanha@redhat.com>
> > 
> > virtiofsd can exceed the default open file descriptor limit easily on
> > most systems.  Take advantage of the fact that it runs as root to raise
> > the limit.
> > 
> > Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
> > ---
> >   tools/virtiofsd/passthrough_ll.c | 32 ++++++++++++++++++++++++++++++++
> >   1 file changed, 32 insertions(+)
> > 
> > diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthrough_ll.c
> > index ab318a6f36..139bf08f4c 100644
> > --- a/tools/virtiofsd/passthrough_ll.c
> > +++ b/tools/virtiofsd/passthrough_ll.c
> > @@ -52,6 +52,7 @@
> >   #include <sys/file.h>
> >   #include <sys/mount.h>
> >   #include <sys/prctl.h>
> > +#include <sys/resource.h>
> >   #include <sys/syscall.h>
> >   #include <sys/types.h>
> >   #include <sys/wait.h>
> > @@ -2250,6 +2251,35 @@ static void setup_sandbox(struct lo_data *lo, struct fuse_session *se)
> >       setup_seccomp();
> >   }
> > +/* Raise the maximum number of open file descriptors */
> > +static void setup_nofile_rlimit(void)
> > +{
> > +    const rlim_t max_fds = 1000000;
> 
> 'static const'?

Why?

> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
> 
Thanks!

> > +    struct rlimit rlim;
> > +
> > +    if (getrlimit(RLIMIT_NOFILE, &rlim) < 0) {
> > +        fuse_log(FUSE_LOG_ERR, "getrlimit(RLIMIT_NOFILE): %m\n");
> > +        exit(1);
> > +    }
> > +
> > +    if (rlim.rlim_cur >= max_fds) {
> > +        return; /* nothing to do */
> > +    }
> > +
> > +    rlim.rlim_cur = max_fds;
> > +    rlim.rlim_max = max_fds;
> > +
> > +    if (setrlimit(RLIMIT_NOFILE, &rlim) < 0) {
> > +        /* Ignore SELinux denials */
> > +        if (errno == EPERM) {
> > +            return;
> > +        }
> > +
> > +        fuse_log(FUSE_LOG_ERR, "setrlimit(RLIMIT_NOFILE): %m\n");
> > +        exit(1);
> > +    }
> > +}
> > +
> >   int main(int argc, char *argv[])
> >   {
> >       struct fuse_args args = FUSE_ARGS_INIT(argc, argv);
> > @@ -2371,6 +2401,8 @@ int main(int argc, char *argv[])
> >       fuse_daemonize(opts.foreground);
> > +    setup_nofile_rlimit();
> > +
> >       /* Must be before sandbox since it wants /proc */
> >       setup_capng();
> > 
> 
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
diff mbox series

Patch

diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthrough_ll.c
index ab318a6f36..139bf08f4c 100644
--- a/tools/virtiofsd/passthrough_ll.c
+++ b/tools/virtiofsd/passthrough_ll.c
@@ -52,6 +52,7 @@ 
 #include <sys/file.h>
 #include <sys/mount.h>
 #include <sys/prctl.h>
+#include <sys/resource.h>
 #include <sys/syscall.h>
 #include <sys/types.h>
 #include <sys/wait.h>
@@ -2250,6 +2251,35 @@  static void setup_sandbox(struct lo_data *lo, struct fuse_session *se)
     setup_seccomp();
 }
 
+/* Raise the maximum number of open file descriptors */
+static void setup_nofile_rlimit(void)
+{
+    const rlim_t max_fds = 1000000;
+    struct rlimit rlim;
+
+    if (getrlimit(RLIMIT_NOFILE, &rlim) < 0) {
+        fuse_log(FUSE_LOG_ERR, "getrlimit(RLIMIT_NOFILE): %m\n");
+        exit(1);
+    }
+
+    if (rlim.rlim_cur >= max_fds) {
+        return; /* nothing to do */
+    }
+
+    rlim.rlim_cur = max_fds;
+    rlim.rlim_max = max_fds;
+
+    if (setrlimit(RLIMIT_NOFILE, &rlim) < 0) {
+        /* Ignore SELinux denials */
+        if (errno == EPERM) {
+            return;
+        }
+
+        fuse_log(FUSE_LOG_ERR, "setrlimit(RLIMIT_NOFILE): %m\n");
+        exit(1);
+    }
+}
+
 int main(int argc, char *argv[])
 {
     struct fuse_args args = FUSE_ARGS_INIT(argc, argv);
@@ -2371,6 +2401,8 @@  int main(int argc, char *argv[])
 
     fuse_daemonize(opts.foreground);
 
+    setup_nofile_rlimit();
+
     /* Must be before sandbox since it wants /proc */
     setup_capng();