Re: [Qemu-devel] [PATCH 1/2] virtio-9p: make virtio-9p available to all POSIX systems

[Blue Swirl]

On Wed, May 26, 2010 at 6:02 PM, Venkateswararao Jujjuri (JV)
<address@hidden> wrote:
> Blue Swirl wrote:
>> On Mon, May 24, 2010 at 8:46 PM, Venkateswararao Jujjuri (JV)
>> <address@hidden> wrote:
>>> Blue Swirl wrote:
>>>> Field d_off in struct dirent is Linux specific.
>>>>
>>>> Signed-off-by: Blue Swirl <address@hidden>
>>>> ---
>>>>  Makefile.objs   |    8 ++++----
>>>>  Makefile.target |    2 +-
>>>>  hw/virtio-9p.c  |    2 +-
>>>>  hw/virtio-pci.c |    6 +++---
>>>>  hw/virtio.h     |    4 ++--
>>>>  qemu-config.c   |    4 ++--
>>>>  qemu-config.h   |    2 +-
>>>>  qemu-options.hx |    8 ++++----
>>>>  vl.c            |    8 ++++----
>>>>  9 files changed, 22 insertions(+), 22 deletions(-)
>>>>
>>>> diff --git a/Makefile.objs b/Makefile.objs
>>>> index 1585101..b1a6e01 100644
>>>> --- a/Makefile.objs
>>>> +++ b/Makefile.objs
>>>> @@ -35,8 +35,8 @@ net-nested-$(CONFIG_SLIRP) += slirp.o
>>>>  net-nested-$(CONFIG_VDE) += vde.o
>>>>  net-obj-y += $(addprefix net/, $(net-nested-y))
>>>>
>>>> -fsdev-nested-$(CONFIG_LINUX) = qemu-fsdev.o
>>>> -fsdev-obj-$(CONFIG_LINUX) += $(addprefix fsdev/, $(fsdev-nested-y))
>>>> +fsdev-nested-$(CONFIG_POSIX) = qemu-fsdev.o
>>>> +fsdev-obj-$(CONFIG_POSIX) += $(addprefix fsdev/, $(fsdev-nested-y))
>>>>
>>>>  ######################################################################
>>>>  # libqemu_common.a: Target independent part of system emulation. The
>>>> @@ -47,7 +47,7 @@ fsdev-obj-$(CONFIG_LINUX) += $(addprefix fsdev/,
>>>> $(fsdev-nested-y))
>>>>  common-obj-y = $(block-obj-y)
>>>>  common-obj-y += $(net-obj-y)
>>>>  common-obj-y += $(qobject-obj-y)
>>>> -common-obj-$(CONFIG_LINUX) += $(fsdev-obj-$(CONFIG_LINUX))
>>>> +common-obj-$(CONFIG_POSIX) += $(fsdev-obj-$(CONFIG_POSIX))
>>>>  common-obj-y += readline.o console.o async.o qemu-error.o
>>>>  common-obj-y += tcg-runtime.o host-utils.o
>>>>  common-obj-y += irq.o ioport.o input.o
>>>> @@ -229,7 +229,7 @@ sound-obj-$(CONFIG_CS4231A) += cs4231a.o
>>>>  adlib.o fmopl.o: QEMU_CFLAGS += -DBUILD_Y8950=0
>>>>  hw-obj-$(CONFIG_SOUND) += $(sound-obj-y)
>>>>
>>>> -hw-obj-$(CONFIG_LINUX) += virtio-9p-debug.o virtio-9p-local.o
>>>> +hw-obj-$(CONFIG_POSIX) += virtio-9p-debug.o virtio-9p-local.o
>>>>
>>>>  ######################################################################
>>>>  # libdis
>>>> diff --git a/Makefile.target b/Makefile.target
>>>> index fda5bf3..00e140f 100644
>>>> --- a/Makefile.target
>>>> +++ b/Makefile.target
>>>> @@ -168,7 +168,7 @@ obj-y += virtio-blk.o virtio-balloon.o
>>>> virtio-net.o virtio-serial-bus.o
>>>>  obj-$(CONFIG_VIRTIO_PCI) += virtio-pci.o
>>>>  obj-y += vhost_net.o
>>>>  obj-$(CONFIG_VHOST_NET) += vhost.o
>>>> -obj-$(CONFIG_LINUX) += virtio-9p.o
>>>> +obj-$(CONFIG_POSIX) += virtio-9p.o
>>>>  obj-y += rwhandler.o
>>>>  obj-$(CONFIG_KVM) += kvm.o kvm-all.o
>>>>  obj-$(CONFIG_NO_KVM) += kvm-stub.o
>>>> diff --git a/hw/virtio-9p.c b/hw/virtio-9p.c
>>>> index e5d0112..68b0696 100644
>>>> --- a/hw/virtio-9p.c
>>>> +++ b/hw/virtio-9p.c
>>>> @@ -1447,8 +1447,8 @@ static void v9fs_read_post_dir_lstat(V9fsState
>>>> *s, V9fsReadState *vs,
>>>>      vs->count += vs->len;
>>>>      v9fs_stat_free(&vs->v9stat);
>>>>      v9fs_string_free(&vs->name);
>>>> -    vs->dir_pos = vs->dent->d_off;
>>>>      vs->dent = v9fs_do_readdir(s, vs->fidp->dir);
>>>> +    vs->dir_pos = v9fs_do_telldir(s, vs->fidp->dir);
>>>
>>> We need to save the the current dir position before making next readdir
>>> We need to seek back if we can't fit it into PDU.
>>> Hence moving the dir_pos after readdir is not a good idea.
>>
>> Hmm, the manual page for readdir says:
>>        On Linux, the dirent structure is defined as follows:
>>
>>            struct dirent {
>>                ino_t          d_ino;       /* inode number */
>>                off_t          d_off;       /* offset to the next dirent */
>>                unsigned short d_reclen;    /* length of this record */
>>                unsigned char  d_type;      /* type of file */
>>                char           d_name[256]; /* filename */
>>            };
>>
>> My change was based on the comment for d_off.
>>
>> But when I run this program:
>>
>> $ cat dirent.c
>> #include <sys/types.h>
>> #include <dirent.h>
>> #include <stdio.h>
>>
>> int main(int argc, const char **argv)
>> {
>>     DIR *d;
>>     struct dirent *entry;
>>     off_t pos;
>>
>>     d = opendir(argv[1]);
>>     entry = readdir(d);
>>     do {
>>         pos = telldir(d);
>>         printf("name %s d_off %ld ino %ld pos %ld\n", entry->d_name,
>> entry->d_off, entry->d_ino, pos);
>>         entry = readdir(d);
>>     } while (entry);
>>     closedir(d);
>>
>>     return 0;
>> }
>>
>> d_off is equal to telldir value:
>
> I don't think there is any dispute there.. All I am saying is
>
> Your diff was this:
>
> -    vs->dir_pos = vs->dent->d_off;
>      vs->dent = v9fs_do_readdir(s, vs->fidp->dir);
> +    vs->dir_pos = v9fs_do_telldir(s, vs->fidp->dir);
>
>
> It should be:
> -    vs->dir_pos = vs->dent->d_off;
> +   vs->dir_pos = v9fs_do_telldir(s, vs->fidp->dir);
>      vs->dent = v9fs_do_readdir(s, vs->fidp->dir);
>

Fully agree. I just interpreted the comment in the manual page so that
d_off would be the offset to the next dirent while in reality it's the
offset of the dirent in question. So telldir returns the same offset
as d_off.

>
>> $ ./dirent /
>> name tmp d_off 206002973 ino 56 pos 206002973
>> name root d_off 224116791 ino 521217 pos 224116791
>> name vmlinuz.old d_off 255549115 ino 17 pos 255549115
>> name dev d_off 378658993 ino 374625 pos 378658993
>>
>> I'll send an updated patch.
>>
>>> BTW, Thanks for making VirtFS generic to all POSIX systems.
>>>
>>> Thanks,
>>> JV.
>>>
>>>>      v9fs_read_post_readdir(s, vs, err);
>>>>      return;
>>>>  out:
>>>> diff --git a/hw/virtio-pci.c b/hw/virtio-pci.c
>>>> index 7ddf612..0a74781 100644
>>>> --- a/hw/virtio-pci.c
>>>> +++ b/hw/virtio-pci.c
>>>> @@ -102,7 +102,7 @@ typedef struct {
>>>>      BlockConf block;
>>>>      NICConf nic;
>>>>      uint32_t host_features;
>>>> -#ifdef CONFIG_LINUX
>>>> +#ifdef CONFIG_POSIX
>>>>      V9fsConf fsconf;
>>>>  #endif
>>>>      /* Max. number of ports we can have for a the virtio-serial device */
>>>> @@ -642,7 +642,7 @@ static int virtio_balloon_init_pci(PCIDevice *pci_dev)
>>>>      return 0;
>>>>  }
>>>>
>>>> -#ifdef CONFIG_LINUX
>>>> +#ifdef CONFIG_POSIX
>>>>  static int virtio_9p_init_pci(PCIDevice *pci_dev)
>>>>  {
>>>>      VirtIOPCIProxy *proxy = DO_UPCAST(VirtIOPCIProxy, pci_dev, pci_dev);
>>>> @@ -713,7 +713,7 @@ static PCIDeviceInfo virtio_info[] = {
>>>>          },
>>>>          .qdev.reset = virtio_pci_reset,
>>>>      },{
>>>> -#ifdef CONFIG_LINUX
>>>> +#ifdef CONFIG_POSIX
>>>>          .qdev.name = "virtio-9p-pci",
>>>>          .qdev.size = sizeof(VirtIOPCIProxy),
>>>>          .init      = virtio_9p_init_pci,
>>>> diff --git a/hw/virtio.h b/hw/virtio.h
>>>> index e4306cd..e77af13 100644
>>>> --- a/hw/virtio.h
>>>> +++ b/hw/virtio.h
>>>> @@ -20,7 +20,7 @@
>>>>  #include "sysemu.h"
>>>>  #include "block_int.h"
>>>>  #include "event_notifier.h"
>>>> -#ifdef CONFIG_LINUX
>>>> +#ifdef CONFIG_POSIX
>>>>  #include "9p.h"
>>>>  #endif
>>>>
>>>> @@ -188,7 +188,7 @@ VirtIODevice *virtio_blk_init(DeviceState *dev,
>>>> BlockConf *conf);
>>>>  VirtIODevice *virtio_net_init(DeviceState *dev, NICConf *conf);
>>>>  VirtIODevice *virtio_serial_init(DeviceState *dev, uint32_t max_nr_ports);
>>>>  VirtIODevice *virtio_balloon_init(DeviceState *dev);
>>>> -#ifdef CONFIG_LINUX
>>>> +#ifdef CONFIG_POSIX
>>>>  VirtIODevice *virtio_9p_init(DeviceState *dev, V9fsConf *conf);
>>>>  #endif
>>>>
>>>> diff --git a/qemu-config.c b/qemu-config.c
>>>> index d500885..78e80e3 100644
>>>> --- a/qemu-config.c
>>>> +++ b/qemu-config.c
>>>> @@ -151,7 +151,7 @@ QemuOptsList qemu_chardev_opts = {
>>>>      },
>>>>  };
>>>>
>>>> -#ifdef CONFIG_LINUX
>>>> +#ifdef CONFIG_POSIX
>>>>  QemuOptsList qemu_fsdev_opts = {
>>>>      .name = "fsdev",
>>>>      .implied_opt_name = "fstype",
>>>> @@ -169,7 +169,7 @@ QemuOptsList qemu_fsdev_opts = {
>>>>  };
>>>>  #endif
>>>>
>>>> -#ifdef CONFIG_LINUX
>>>> +#ifdef CONFIG_POSIX
>>>>  QemuOptsList qemu_virtfs_opts = {
>>>>      .name = "virtfs",
>>>>      .implied_opt_name = "fstype",
>>>> diff --git a/qemu-config.h b/qemu-config.h
>>>> index dca69d4..5376935 100644
>>>> --- a/qemu-config.h
>>>> +++ b/qemu-config.h
>>>> @@ -3,7 +3,7 @@
>>>>
>>>>  extern QemuOptsList qemu_drive_opts;
>>>>  extern QemuOptsList qemu_chardev_opts;
>>>> -#ifdef CONFIG_LINUX
>>>> +#ifdef CONFIG_POSIX
>>>>  extern QemuOptsList qemu_fsdev_opts;
>>>>  extern QemuOptsList qemu_virtfs_opts;
>>>>  #endif
>>>> diff --git a/qemu-options.hx b/qemu-options.hx
>>>> index 03e95fd..34ed806 100644
>>>> --- a/qemu-options.hx
>>>> +++ b/qemu-options.hx
>>>> @@ -475,7 +475,7 @@ possible drivers and properties, use @code{-device ?} 
>>>> and
>>>> address@hidden @var{driver},?}.
>>>>  ETEXI
>>>>
>>>> -#ifdef CONFIG_LINUX
>>>> +#ifdef CONFIG_POSIX
>>>>  DEFHEADING(File system options:)
>>>>
>>>>  DEF("fsdev", HAS_ARG, QEMU_OPTION_fsdev,
>>>> @@ -499,7 +499,7 @@ Options to each backend are described below.
>>>>
>>>>  Create a file-system-"device" for local-filesystem.
>>>>
>>>> address@hidden is only available on Linux.
>>>> address@hidden is only available on POSIX systems.
>>>>
>>>> address@hidden specifies the path to be exported. @option{path} is 
>>>> required.
>>>>
>>>> @@ -507,7 +507,7 @@ Create a file-system-"device" for local-filesystem.
>>>>  ETEXI
>>>>  #endif
>>>>
>>>> -#ifdef CONFIG_LINUX
>>>> +#ifdef CONFIG_POSIX
>>>>  DEFHEADING(Virtual File system pass-through options:)
>>>>
>>>>  DEF("virtfs", HAS_ARG, QEMU_OPTION_virtfs,
>>>> @@ -531,7 +531,7 @@ Options to each backend are described below.
>>>>
>>>>  Create a Virtual file-system-pass through for local-filesystem.
>>>>
>>>> address@hidden is only available on Linux.
>>>> address@hidden is only available on POSIX systems.
>>>>
>>>> address@hidden specifies the path to be exported. @option{path} is 
>>>> required.
>>>>
>>>> diff --git a/vl.c b/vl.c
>>>> index d77b47c..d5c1e34 100644
>>>> --- a/vl.c
>>>> +++ b/vl.c
>>>> @@ -149,7 +149,7 @@ int main(int argc, char **argv)
>>>>  #include "qemu-option.h"
>>>>  #include "qemu-config.h"
>>>>  #include "qemu-objects.h"
>>>> -#ifdef CONFIG_LINUX
>>>> +#ifdef CONFIG_POSIX
>>>>  #include "fsdev/qemu-fsdev.h"
>>>>  #endif
>>>>
>>>> @@ -2314,7 +2314,7 @@ static int chardev_init_func(QemuOpts *opts, void 
>>>> *opaque)
>>>>      return 0;
>>>>  }
>>>>
>>>> -#ifdef CONFIG_LINUX
>>>> +#ifdef CONFIG_POSIX
>>>>  static int fsdev_init_func(QemuOpts *opts, void *opaque)
>>>>  {
>>>>      int ret;
>>>> @@ -3090,7 +3090,7 @@ int main(int argc, char **argv, char **envp)
>>>>                      exit(1);
>>>>                  }
>>>>                  break;
>>>> -#ifdef CONFIG_LINUX
>>>> +#ifdef CONFIG_POSIX
>>>>              case QEMU_OPTION_fsdev:
>>>>                  opts = qemu_opts_parse(&qemu_fsdev_opts, optarg, 1);
>>>>                  if (!opts) {
>>>> @@ -3513,7 +3513,7 @@ int main(int argc, char **argv, char **envp)
>>>>
>>>>      if (qemu_opts_foreach(&qemu_chardev_opts, chardev_init_func, NULL, 1) 
>>>> != 0)
>>>>          exit(1);
>>>> -#ifdef CONFIG_LINUX
>>>> +#ifdef CONFIG_POSIX
>>>>      if (qemu_opts_foreach(&qemu_fsdev_opts, fsdev_init_func, NULL, 1) != 
>>>> 0) {
>>>>          exit(1);
>>>>      }
>>>
>>>
>
>
>