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Re: [Qemu-devel] [RESEND] [PATCH] hw/9pfs: fix P9_STATS_GEN handling
From: |
Aneesh Kumar K.V |
Subject: |
Re: [Qemu-devel] [RESEND] [PATCH] hw/9pfs: fix P9_STATS_GEN handling |
Date: |
Thu, 07 Nov 2013 12:15:18 +0530 |
User-agent: |
Notmuch/0.16+99~g10596a5 (http://notmuchmail.org) Emacs/24.3.1 (x86_64-pc-linux-gnu) |
"Kirill A. Shutemov" <address@hidden> writes:
> From: "Kirill A. Shutemov" <address@hidden>
>
> Currently we have few issues with P9_STATS_GEN:
>
> - We don't try to read st_gen anything except files or directories, but
> still set P9_STATS_GEN bit in st_result_mask. It may mislead client:
> we present garbage as valid st_gen.
>
> - If we failed to get valid st_gen with ENOTTY, we ignore error, but
> still set P9_STATS_GEN bit in st_result_mask.
>
> - If we failed to get valid st_gen with any other errno, we fail
> getattr altogether. It's excessive: we block valid client use-cases,
> like chdir(2) to non-readable directory with execution bit set.
>
> The patch fixes these issues and cleanup code a bit.
>
> Signed-off-by: Kirill A. Shutemov <address@hidden>
> Reviewed-by: Daniel P. Berrange <address@hidden>
Reviewed-by: Aneesh Kumar K.V <address@hidden>
> ---
> hw/9pfs/cofile.c | 4 ----
> hw/9pfs/virtio-9p-handle.c | 8 +++++++-
> hw/9pfs/virtio-9p-local.c | 10 ++++++----
> hw/9pfs/virtio-9p-proxy.c | 3 ++-
> hw/9pfs/virtio-9p.c | 12 ++++++++++--
> 5 files changed, 25 insertions(+), 12 deletions(-)
>
> diff --git a/hw/9pfs/cofile.c b/hw/9pfs/cofile.c
> index 194c1306c665..2efebf35710f 100644
> --- a/hw/9pfs/cofile.c
> +++ b/hw/9pfs/cofile.c
> @@ -38,10 +38,6 @@ int v9fs_co_st_gen(V9fsPDU *pdu, V9fsPath *path, mode_t
> st_mode,
> });
> v9fs_path_unlock(s);
> }
> - /* The ioctl may not be supported depending on the path */
> - if (err == -ENOTTY) {
> - err = 0;
> - }
> return err;
> }
>
> diff --git a/hw/9pfs/virtio-9p-handle.c b/hw/9pfs/virtio-9p-handle.c
> index fe8e0ed19dcc..17002a3d2867 100644
> --- a/hw/9pfs/virtio-9p-handle.c
> +++ b/hw/9pfs/virtio-9p-handle.c
> @@ -582,6 +582,7 @@ static int handle_unlinkat(FsContext *ctx, V9fsPath *dir,
> static int handle_ioc_getversion(FsContext *ctx, V9fsPath *path,
> mode_t st_mode, uint64_t *st_gen)
> {
> +#ifdef FS_IOC_GETVERSION
> int err;
> V9fsFidOpenState fid_open;
>
> @@ -590,7 +591,8 @@ static int handle_ioc_getversion(FsContext *ctx, V9fsPath
> *path,
> * We can get fd for regular files and directories only
> */
> if (!S_ISREG(st_mode) && !S_ISDIR(st_mode)) {
> - return 0;
> + errno = ENOTTY;
> + return -1;
> }
> err = handle_open(ctx, path, O_RDONLY, &fid_open);
> if (err < 0) {
> @@ -599,6 +601,10 @@ static int handle_ioc_getversion(FsContext *ctx,
> V9fsPath *path,
> err = ioctl(fid_open.fd, FS_IOC_GETVERSION, st_gen);
> handle_close(ctx, &fid_open);
> return err;
> +#else
> + errno = ENOTTY;
> + return -1;
> +#endif
> }
>
> static int handle_init(FsContext *ctx)
> diff --git a/hw/9pfs/virtio-9p-local.c b/hw/9pfs/virtio-9p-local.c
> index fc93e9e6e8da..df0dbffa7ac4 100644
> --- a/hw/9pfs/virtio-9p-local.c
> +++ b/hw/9pfs/virtio-9p-local.c
> @@ -1068,8 +1068,8 @@ err_out:
> static int local_ioc_getversion(FsContext *ctx, V9fsPath *path,
> mode_t st_mode, uint64_t *st_gen)
> {
> - int err;
> #ifdef FS_IOC_GETVERSION
> + int err;
> V9fsFidOpenState fid_open;
>
> /*
> @@ -1077,7 +1077,8 @@ static int local_ioc_getversion(FsContext *ctx,
> V9fsPath *path,
> * We can get fd for regular files and directories only
> */
> if (!S_ISREG(st_mode) && !S_ISDIR(st_mode)) {
> - return 0;
> + errno = ENOTTY;
> + return -1;
> }
> err = local_open(ctx, path, O_RDONLY, &fid_open);
> if (err < 0) {
> @@ -1085,10 +1086,11 @@ static int local_ioc_getversion(FsContext *ctx,
> V9fsPath *path,
> }
> err = ioctl(fid_open.fd, FS_IOC_GETVERSION, st_gen);
> local_close(ctx, &fid_open);
> + return err;
> #else
> - err = -ENOTTY;
> + errno = ENOTTY;
> + return -1;
> #endif
> - return err;
> }
>
> static int local_init(FsContext *ctx)
> diff --git a/hw/9pfs/virtio-9p-proxy.c b/hw/9pfs/virtio-9p-proxy.c
> index 5f44bb758b35..b57966d9d883 100644
> --- a/hw/9pfs/virtio-9p-proxy.c
> +++ b/hw/9pfs/virtio-9p-proxy.c
> @@ -1086,7 +1086,8 @@ static int proxy_ioc_getversion(FsContext *fs_ctx,
> V9fsPath *path,
> * we can get fd for regular files and directories only
> */
> if (!S_ISREG(st_mode) && !S_ISDIR(st_mode)) {
> - return 0;
> + errno = ENOTTY;
> + return -1;
> }
> err = v9fs_request(fs_ctx->private, T_GETVERSION, st_gen, "s", path);
> if (err < 0) {
> diff --git a/hw/9pfs/virtio-9p.c b/hw/9pfs/virtio-9p.c
> index 8cbb8ae32a03..3e51fcd152f8 100644
> --- a/hw/9pfs/virtio-9p.c
> +++ b/hw/9pfs/virtio-9p.c
> @@ -1080,10 +1080,18 @@ static void v9fs_getattr(void *opaque)
> /* fill st_gen if requested and supported by underlying fs */
> if (request_mask & P9_STATS_GEN) {
> retval = v9fs_co_st_gen(pdu, &fidp->path, stbuf.st_mode,
> &v9stat_dotl);
> - if (retval < 0) {
> + switch (retval) {
> + case 0:
> + /* we have valid st_gen: update result mask */
> + v9stat_dotl.st_result_mask |= P9_STATS_GEN;
> + break;
> + case -EINTR:
> + /* request cancelled */
> goto out;
> + default:
> + /* failed to get st_gen: not fatal, ignore */
> + break;
> }
> - v9stat_dotl.st_result_mask |= P9_STATS_GEN;
> }
> retval = pdu_marshal(pdu, offset, "A", &v9stat_dotl);
> if (retval < 0) {
> --
> 1.8.4.2