Patchwork [-V3,6/8] hw/9pfs: Add directory reclaim support

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Submitter Aneesh Kumar K.V
Date March 5, 2011, 5:52 p.m.
Message ID <1299347533-17047-6-git-send-email-aneesh.kumar@linux.vnet.ibm.com>
Download mbox | patch
Permalink /patch/85545/
State New
Headers show

Comments

Aneesh Kumar K.V - March 5, 2011, 5:52 p.m.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 hw/9pfs/virtio-9p.c |   21 +++++++++++++++++++--
 1 files changed, 19 insertions(+), 2 deletions(-)
Stefan Hajnoczi - March 13, 2011, 4:42 p.m.
On Sat, Mar 5, 2011 at 5:52 PM, Aneesh Kumar K.V
<aneesh.kumar@linux.vnet.ibm.com> wrote:
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
> ---
>  hw/9pfs/virtio-9p.c |   21 +++++++++++++++++++--
>  1 files changed, 19 insertions(+), 2 deletions(-)
>
> diff --git a/hw/9pfs/virtio-9p.c b/hw/9pfs/virtio-9p.c
> index 1fa7256..293a562 100644
> --- a/hw/9pfs/virtio-9p.c
> +++ b/hw/9pfs/virtio-9p.c
> @@ -142,7 +142,12 @@ static int v9fs_do_open(V9fsState *s, V9fsString *path, int flags)
>
>  static DIR *v9fs_do_opendir(V9fsState *s, V9fsString *path)
>  {
> -    return s->ops->opendir(&s->ctx, path->data);
> +    DIR *dir;
> +    dir = s->ops->opendir(&s->ctx, path->data);
> +    if (dirfd(dir) > P9_FD_RECLAIM_THRES) {
> +        v9fs_reclaim_fd(s);
> +    }

dirfd(NULL) will crash so we need to check !dir first:

$ cat dirfd.c
#include <stdio.h>

int main(int argc, char **argv)
{
        printf("%d\n", dirfd(NULL));
        return 0;
}

$ gcc -o dirfd dirfd.c
$ ./dirfd
Segmentation fault

Stefan
Aneesh Kumar K.V - March 13, 2011, 7:02 p.m.
On Sun, 13 Mar 2011 16:42:56 +0000, Stefan Hajnoczi <stefanha@gmail.com> wrote:
> On Sat, Mar 5, 2011 at 5:52 PM, Aneesh Kumar K.V
> <aneesh.kumar@linux.vnet.ibm.com> wrote:
> > Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
> > ---
> >  hw/9pfs/virtio-9p.c |   21 +++++++++++++++++++--
> >  1 files changed, 19 insertions(+), 2 deletions(-)
> >
> > diff --git a/hw/9pfs/virtio-9p.c b/hw/9pfs/virtio-9p.c
> > index 1fa7256..293a562 100644
> > --- a/hw/9pfs/virtio-9p.c
> > +++ b/hw/9pfs/virtio-9p.c
> > @@ -142,7 +142,12 @@ static int v9fs_do_open(V9fsState *s, V9fsString *path, int flags)
> >
> >  static DIR *v9fs_do_opendir(V9fsState *s, V9fsString *path)
> >  {
> > -    return s->ops->opendir(&s->ctx, path->data);
> > +    DIR *dir;
> > +    dir = s->ops->opendir(&s->ctx, path->data);
> > +    if (dirfd(dir) > P9_FD_RECLAIM_THRES) {
> > +        v9fs_reclaim_fd(s);
> > +    }
> 
> dirfd(NULL) will crash so we need to check !dir first:
> 

Will add the check

-aneesh

Patch

diff --git a/hw/9pfs/virtio-9p.c b/hw/9pfs/virtio-9p.c
index 1fa7256..293a562 100644
--- a/hw/9pfs/virtio-9p.c
+++ b/hw/9pfs/virtio-9p.c
@@ -142,7 +142,12 @@  static int v9fs_do_open(V9fsState *s, V9fsString *path, int flags)
 
 static DIR *v9fs_do_opendir(V9fsState *s, V9fsString *path)
 {
-    return s->ops->opendir(&s->ctx, path->data);
+    DIR *dir;
+    dir = s->ops->opendir(&s->ctx, path->data);
+    if (dirfd(dir) > P9_FD_RECLAIM_THRES) {
+        v9fs_reclaim_fd(s);
+    }
+    return dir;
 }
 
 static void v9fs_do_rewinddir(V9fsState *s, DIR *dir)
@@ -484,6 +489,10 @@  static V9fsFidState *lookup_fid(V9fsState *s, int32_t fid)
                     f->fsmap.fs.fd = v9fs_do_open(s, &f->fsmap.path,
                                                   f->fsmap.open_flags);
                 }
+            } else if (f->fsmap.fid_type == P9_FID_DIR) {
+                if (f->fsmap.fs.dir == NULL) {
+                    f->fsmap.fs.dir = v9fs_do_opendir(s, &f->fsmap.path);
+                }
             }
             /*
              * Mark the fid as referenced so that the LRU
@@ -550,6 +559,12 @@  static void v9fs_reclaim_fd(V9fsState *s)
                 f->fsmap.fs.fd = -1;
                 reclaim_count++;
             }
+        } else if (f->fsmap.fid_type == P9_FID_DIR) {
+            if (f->fsmap.fs.dir != NULL) {
+                v9fs_do_closedir(s, f->fsmap.fs.dir);
+                f->fsmap.fs.dir = NULL;
+                reclaim_count++;
+            }
         }
         if (reclaim_count >= P9_FD_RECLAIM_THRES/2) {
             break;
@@ -633,7 +648,9 @@  static int free_fid(V9fsState *s, int32_t fid)
             v9fs_do_close(s, fidp->fsmap.fs.fd);
         }
     } else if (fidp->fsmap.fid_type == P9_FID_DIR) {
-        v9fs_do_closedir(s, fidp->fsmap.fs.dir);
+        if (fidp->fsmap.fs.dir != NULL) {
+            v9fs_do_closedir(s, fidp->fsmap.fs.dir);
+        }
     } else if (fidp->fsmap.fid_type == P9_FID_XATTR) {
         retval = v9fs_xattr_fid_clunk(s, fidp);
     }