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[1/3] 9pfs: add cleanup operation in FileOperations

Message ID 5829af0b.84f4420a.a436f.4a6d@mx.google.com (mailing list archive)
State New, archived
Headers show

Commit Message

Li Qiang Nov. 14, 2016, 12:32 p.m. UTC 
From: Li Qiang <liq3ea@gmail.com>

Currently, the backend of VirtFS doesn't have a cleanup
function. This will lead resource leak issues if the backed
driver allocates resources. This patch addresses this issue.

Signed-off-by: Li Qiang <liq3ea@gmail.com>
---
 fsdev/file-op-9p.h | 1 +
 hw/9pfs/9p.c       | 3 +++
 2 files changed, 4 insertions(+)

Comments

Greg Kurz Nov. 14, 2016, 5:32 p.m. UTC | #1 
On Mon, 14 Nov 2016 07:32:56 -0500
Li Qiang <liq3ea@gmail.com> wrote:

> From: Li Qiang <liq3ea@gmail.com>
> 
> Currently, the backend of VirtFS doesn't have a cleanup
> function. This will lead resource leak issues if the backed
> driver allocates resources. This patch addresses this issue.
> 
> Signed-off-by: Li Qiang <liq3ea@gmail.com>
> ---
>  fsdev/file-op-9p.h | 1 +
>  hw/9pfs/9p.c       | 3 +++
>  2 files changed, 4 insertions(+)
> 
> diff --git a/fsdev/file-op-9p.h b/fsdev/file-op-9p.h
> index 6db9fea..a56dc84 100644
> --- a/fsdev/file-op-9p.h
> +++ b/fsdev/file-op-9p.h
> @@ -100,6 +100,7 @@ struct FileOperations
>  {
>      int (*parse_opts)(QemuOpts *, struct FsDriverEntry *);
>      int (*init)(struct FsContext *);
> +    void (*cleanup)(struct FsContext *);
>      int (*lstat)(FsContext *, V9fsPath *, struct stat *);
>      ssize_t (*readlink)(FsContext *, V9fsPath *, char *, size_t);
>      int (*chmod)(FsContext *, V9fsPath *, FsCred *);
> diff --git a/hw/9pfs/9p.c b/hw/9pfs/9p.c
> index aea7e9d..166b5a7 100644
> --- a/hw/9pfs/9p.c
> +++ b/hw/9pfs/9p.c
> @@ -3532,6 +3532,9 @@ void v9fs_device_unrealize_common(V9fsState *s, Error **errp)
>  {
>      g_free(s->ctx.fs_root);
>      g_free(s->tag);
> +    if (s->ops->cleanup) {
> +        s->ops->cleanup(&s->ctx);
> +    }

Unrealize should undo things that were set during realize in reverse order: 
please move the cleanup stuff above calls to g_free() (which are actually
misordered since tag is allocated after fs_root... maybe you can fix that
too in a preparatory patch).

You also have to call cleanup in the error path of realize if init was
called.

>  }
>  
>  typedef struct VirtfsCoResetData {
diff mbox

Patch

diff --git a/fsdev/file-op-9p.h b/fsdev/file-op-9p.h
index 6db9fea..a56dc84 100644
--- a/fsdev/file-op-9p.h
+++ b/fsdev/file-op-9p.h
@@ -100,6 +100,7 @@  struct FileOperations
 {
     int (*parse_opts)(QemuOpts *, struct FsDriverEntry *);
     int (*init)(struct FsContext *);
+    void (*cleanup)(struct FsContext *);
     int (*lstat)(FsContext *, V9fsPath *, struct stat *);
     ssize_t (*readlink)(FsContext *, V9fsPath *, char *, size_t);
     int (*chmod)(FsContext *, V9fsPath *, FsCred *);
diff --git a/hw/9pfs/9p.c b/hw/9pfs/9p.c
index aea7e9d..166b5a7 100644
--- a/hw/9pfs/9p.c
+++ b/hw/9pfs/9p.c
@@ -3532,6 +3532,9 @@  void v9fs_device_unrealize_common(V9fsState *s, Error **errp)
 {
     g_free(s->ctx.fs_root);
     g_free(s->tag);
+    if (s->ops->cleanup) {
+        s->ops->cleanup(&s->ctx);
+    }
 }
 
 typedef struct VirtfsCoResetData {