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Re: [Qemu-devel] [PATCH v3 09/19] block: raw-posix image file reopen
From: |
Jeff Cody |
Subject: |
Re: [Qemu-devel] [PATCH v3 09/19] block: raw-posix image file reopen |
Date: |
Tue, 18 Sep 2012 18:20:05 -0400 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:15.0) Gecko/20120828 Thunderbird/15.0 |
On 09/18/2012 05:20 PM, Eric Blake wrote:
> On 09/18/2012 12:53 PM, Jeff Cody wrote:
>> This is derived from the Supriya Kannery's reopen patches.
>>
>> This contains the raw-posix driver changes for the bdrv_reopen_*
>> functions. All changes are staged into a temporary scratch buffer
>> during the prepare() stage, and copied over to the live structure
>> during commit(). Upon abort(), all changes are abandoned, and the
>> live structures are unmodified.
>>
>> The _prepare() will create an extra fd - either by means of a dup,
>> if possible, or opening a new fd if not (for instance, access
>> control changes). Upon _commit(), the original fd is closed and
>> the new fd is used. Upon _abort(), the duplicate/new fd is closed.
>>
>> Signed-off-by: Jeff Cody <address@hidden>
>> ---
>> block/raw-posix.c | 99
>> +++++++++++++++++++++++++++++++++++++++++++++++++++++++
>> 1 file changed, 99 insertions(+)
>>
>> diff --git a/block/raw-posix.c b/block/raw-posix.c
>> index 6bf5480..edd1eca 100644
>> --- a/block/raw-posix.c
>> +++ b/block/raw-posix.c
>> @@ -138,6 +138,15 @@ typedef struct BDRVRawState {
>> #endif
>> } BDRVRawState;
>>
>> +typedef struct BDRVRawReopenState {
>> + int fd;
>> + int open_flags;
>> +#ifdef CONFIG_LINUX_AIO
>> + int use_aio;
>> + void *aio_ctx;
>> +#endif
>
> These members are conditional...
>
>> +static int raw_reopen_prepare(BDRVReopenState *state,
>> + BlockReopenQueue *queue, Error **errp)
>> +{
>> + BDRVRawState *s;
>> + BDRVRawReopenState *raw_s;
>> + int ret = 0;
>> +
>> + assert(state != NULL);
>> + assert(state->bs != NULL);
>> +
>> + s = state->bs->opaque;
>> +
>> + state->opaque = g_malloc0(sizeof(BDRVRawReopenState));
>> + raw_s = state->opaque;
>> + raw_s->use_aio = s->use_aio;
>> + raw_s->aio_ctx = s->aio_ctx;
>
> ...but you are unconditionally assigning into them. This will introduce
> compile failures on other platforms.
Argh. Thanks.
>
>> + if ((raw_s->open_flags & ~fcntl_flags) == (s->open_flags &
>> ~fcntl_flags)) {
>> + /* dup the original fd */
>> + /* TODO: use qemu fcntl wrapper */
>> + raw_s->fd = fcntl(s->fd, F_DUPFD_CLOEXEC, 0);
>
> F_DUPFD_CLOEXEC is not defined everywhere yet; you still need to address
> your TODO.
>
>> +
>> + /* If we cannot use fctnl, or fcntl failed, fall back to qemu_open() */
>
> s/fctnl/fcntl/
>
>> +static void raw_reopen_commit(BDRVReopenState *state)
>> +{
>> + BDRVRawReopenState *raw_s = state->opaque;
>> + BDRVRawState *s = state->bs->opaque;
>> +
>> + s->open_flags = raw_s->open_flags;
>> +
>> + qemu_close(s->fd);
>> + s->fd = raw_s->fd;
>> + s->use_aio = raw_s->use_aio;
>> + s->aio_ctx = raw_s->aio_ctx;
>
> Again, more unconditional use of conditional members.
>
- Re: [Qemu-devel] [PATCH v3 04/19] block: move aio initialization into a helper function, (continued)
- [Qemu-devel] [PATCH v3 03/19] block: Framework for reopening files safely, Jeff Cody, 2012/09/18
- [Qemu-devel] [PATCH v3 05/19] block: move open flag parsing in raw block drivers to helper functions, Jeff Cody, 2012/09/18
- [Qemu-devel] [PATCH v3 06/19] block: do not parse BDRV_O_CACHE_WB in block drivers, Jeff Cody, 2012/09/18
- [Qemu-devel] [PATCH v3 07/19] block: use BDRV_O_NOCACHE instead of s->aligned_buf in raw-posix.c, Jeff Cody, 2012/09/18
- [Qemu-devel] [PATCH v3 09/19] block: raw-posix image file reopen, Jeff Cody, 2012/09/18
- [Qemu-devel] [PATCH v3 10/19] block: raw image file reopen, Jeff Cody, 2012/09/18
- [Qemu-devel] [PATCH v3 12/19] block: qcow2 image file reopen, Jeff Cody, 2012/09/18
- [Qemu-devel] [PATCH v3 13/19] block: qcow image file reopen, Jeff Cody, 2012/09/18
- [Qemu-devel] [PATCH v3 14/19] block: vmdk image file reopen, Jeff Cody, 2012/09/18
- [Qemu-devel] [PATCH v3 01/19] block: correctly set the keep_read_only flag, Jeff Cody, 2012/09/18
- [Qemu-devel] [PATCH v3 08/19] block: purge s->aligned_buf and s->aligned_buf_size from raw-posix.c, Jeff Cody, 2012/09/18