On Saturday 16 June 2012 03:41 AM, Eric Blake wrote:
On 06/15/2012 02:48 PM, Supriya Kannery wrote:
> raw-posix driver changes for bdrv_reopen_xx functions to
> safely reopen image files. Reopening of image files while
> changing hostcache dynamically is handled here.
>
> Signed-off-by: Supriya Kannery <supri...@linux.vnet.ibm.com>
>
>
> +static int raw_reopen_prepare(BlockDriverState *bs, BDRVReopenState
**prs,
> + int flags)
> +{
> + BDRVRawReopenState *raw_rs = g_malloc0(sizeof(BDRVRawReopenState));
> + BDRVRawState *s = bs->opaque;
> + int ret = 0;
> +
> + raw_rs->reopen_state.bs = bs;
> +
> + /* stash state before reopen */
> + raw_rs->stash_s = g_malloc0(sizeof(BDRVRawState));
> +/* memcpy(raw_rs->stash_s, s, sizeof(BDRVRawState)); */
Why the comment?
> + raw_stash_state(raw_rs->stash_s, s);
> + s->fd = dup(raw_rs->stash_s->fd);
Needs to handle O_CLOEXEC open flag, which means using
fcntl(F_DUPFD_CLOEXEC) when available for atomic support, and a fallback
to fcntl(F_GETFD/F_SETFD) if not.
> +
> + *prs = &(raw_rs->reopen_state);
> +
> + /* Flags that can be set using fcntl */
> + int fcntl_flags = BDRV_O_NOCACHE;
> +
> + if ((bs->open_flags & ~fcntl_flags) == (flags & ~fcntl_flags)) {
> + if ((flags & BDRV_O_NOCACHE)) {
> + s->open_flags |= O_DIRECT;
> + } else {
> + s->open_flags &= ~O_DIRECT;
> + }
> + ret = fcntl_setfl(s->fd, s->open_flags);
> + } else {
> +
> + /* close and reopen using new flags */
> + bs->drv->bdrv_close(bs);
> + ret = bs->drv->bdrv_file_open(bs, bs->filename, flags);
Is this a case where Paolo's proposed bdrv_swap command would be useful?
> + /* revert to stashed state */
> + if (s->fd != -1) {
> + close(s->fd);
> + }
> +/* memcpy(s, raw_rs->stash_s, sizeof(BDRVRawState)); */
Why the comment?
raw-posix driver changes for bdrv_reopen_xx functions to
safely reopen image files. Reopening of image files while
changing hostcache dynamically is handled here.
Signed-off-by: Supriya Kannery <supri...@linux.vnet.ibm.com>
Changed the dup function to dup3 to handle the O_CLOEXEC flag.
Signed-off-by: Shrinidhi Joshi <spjosh...@gmail.com>
Index: qemu/block/raw.c
===================================================================
--- qemu.orig/block/raw.c 2012-06-19 15:52:40.512586150 +0530
+++ qemu/block/raw.c 2012-06-19 17:39:33.572386768 +0530
@@ -9,6 +9,22 @@
return 0;
}
+static int raw_reopen_prepare(BlockDriverState *bs, BDRVReopenState **prs,
+ int flags)
+{
+ return bdrv_reopen_prepare(bs->file, prs, flags);
+}
+
+static void raw_reopen_commit(BlockDriverState *bs, BDRVReopenState *rs)
+{
+ bdrv_reopen_commit(bs->file, rs);
+}
+
+static void raw_reopen_abort(BlockDriverState *bs, BDRVReopenState *rs)
+{
+ bdrv_reopen_abort(bs->file, rs);
+}
+
static int coroutine_fn raw_co_readv(BlockDriverState *bs, int64_t
sector_num,
int nb_sectors, QEMUIOVector *qiov)
{
@@ -111,6 +127,10 @@
.instance_size = 1,
.bdrv_open = raw_open,
+ .bdrv_reopen_prepare
+ = raw_reopen_prepare,
+ .bdrv_reopen_commit = raw_reopen_commit,
+ .bdrv_reopen_abort = raw_reopen_abort,
.bdrv_close = raw_close,
.bdrv_co_readv = raw_co_readv,
Index: qemu/block/raw-posix.c
===================================================================
--- qemu.orig/block/raw-posix.c 2012-06-19 15:52:40.520586178 +0530
+++ qemu/block/raw-posix.c 2012-06-20 15:59:09.036535061 +0530
@@ -140,8 +140,15 @@
#endif
} BDRVRawState;
+typedef struct BDRVRawReopenState {
+ BDRVReopenState reopen_state;
+ BDRVRawState *stash_s;
+} BDRVRawReopenState;
+
static int fd_open(BlockDriverState *bs);
static int64_t raw_getlength(BlockDriverState *bs);
+static void raw_stash_state(BDRVRawState *stashed_state, BDRVRawState *s);
+static void raw_revert_state(BDRVRawState *s, BDRVRawState *stashed_state);
#if defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
static int cdrom_reopen(BlockDriverState *bs);
@@ -283,6 +290,119 @@
return raw_open_common(bs, filename, flags, 0);
}
+static int raw_reopen_prepare(BlockDriverState *bs, BDRVReopenState **prs,
+ int flags)
+{
+ BDRVRawReopenState *raw_rs = g_malloc0(sizeof(BDRVRawReopenState));
+ BDRVRawState *s = bs->opaque;
+ int ret = 0;
+
+ raw_rs->reopen_state.bs = bs;
+
+ /* stash state before reopen */
+ raw_rs->stash_s = g_malloc0(sizeof(BDRVRawState));
+
+ raw_stash_state(raw_rs->stash_s, s);
+ s->fd = dup3(raw_rs->stash_s->fd,s->fd,O_CLOEXEC);
+
+ *prs = &(raw_rs->reopen_state);
+
+ /* Flags that can be set using fcntl */
+ int fcntl_flags = BDRV_O_NOCACHE;
+
+ if ((bs->open_flags & ~fcntl_flags) == (flags & ~fcntl_flags)) {
+ if ((flags & BDRV_O_NOCACHE)) {
+ s->open_flags |= O_DIRECT;
+ } else {
+ s->open_flags &= ~O_DIRECT;
+ }
+ ret = fcntl_setfl(s->fd, s->open_flags);
+ } else {
+
+ /* close and reopen using new flags */
+ bdrv_flush(bs);
+ ret = bs->drv->bdrv_file_open(bs, bs->filename, flags);
+ }
+ return ret;
+}
+
+static void raw_reopen_commit(BlockDriverState *bs, BDRVReopenState *rs)
+{
+ BDRVRawReopenState *raw_rs;
+
+ raw_rs = container_of(rs, BDRVRawReopenState, reopen_state);
+
+ /* clean up stashed state */
+ close(raw_rs->stash_s->fd);
+ g_free(raw_rs->stash_s);
+ g_free(raw_rs);
+}
+
+static void raw_reopen_abort(BlockDriverState *bs, BDRVReopenState *rs)
+{
+ BDRVRawReopenState *raw_rs;
+ BDRVRawState *s = bs->opaque;
+
+ raw_rs = container_of(rs, BDRVRawReopenState, reopen_state);
+
+ /* revert to stashed state */
+ if (s->fd != -1) {
+ close(s->fd);
+ }
+
+ raw_revert_state(s, raw_rs->stash_s);
+ g_free(raw_rs->stash_s);
+ g_free(raw_rs);
+}
+
+static void raw_stash_state(BDRVRawState *stashed_s, BDRVRawState *s)
+{
+ stashed_s->fd = -1;
+ stashed_s->type = s->type;
+ stashed_s->open_flags = s->open_flags;
+#if defined(__linux__)
+ /* linux floppy specific */
+ stashed_s->fd_open_time = s->fd_open_time;
+ stashed_s->fd_error_time = s->fd_error_time;
+ stashed_s->fd_got_error = s->fd_got_error;
+ stashed_s->fd_media_changed = s->fd_media_changed;
+#endif
+#ifdef CONFIG_LINUX_AIO
+ stashed_s->use_aio = s->use_aio;
+ stashed_s->aio_ctx = s->aio_ctx;
+#endif
+ stashed_s->aligned_buf = s->aligned_buf;
+ stashed_s->aligned_buf_size = s->aligned_buf_size;
+#ifdef CONFIG_XFS
+ stashed_s->is_xfs = s->is_xfs;
+#endif
+
+}
+
+static void raw_revert_state(BDRVRawState *s, BDRVRawState *stashed_s)
+{
+
+ s->fd = stashed_s->fd;
+ s->type = stashed_s->type;
+ s->open_flags = stashed_s->open_flags;
+#if defined(__linux__)
+ /* linux floppy specific */
+ s->fd_open_time = stashed_s->fd_open_time;
+ s->fd_error_time = stashed_s->fd_error_time;
+ s->fd_got_error = stashed_s->fd_got_error;
+ s->fd_media_changed = stashed_s->fd_media_changed;
+#endif
+#ifdef CONFIG_LINUX_AIO
+ s->use_aio = stashed_s->use_aio;
+ s->aio_ctx = stashed_s->aio_ctx;
+#endif
+ s->aligned_buf = stashed_s->aligned_buf;
+ s->aligned_buf_size = stashed_s->aligned_buf_size;
+#ifdef CONFIG_XFS
+ s->is_xfs = stashed_s->is_xfs;
+#endif
+}
+
/* XXX: use host sector size if necessary with:
#ifdef DIOCGSECTORSIZE
{
@@ -728,6 +848,9 @@
.instance_size = sizeof(BDRVRawState),
.bdrv_probe = NULL, /* no probe for protocols */
.bdrv_file_open = raw_open,
+ .bdrv_reopen_prepare = raw_reopen_prepare,
+ .bdrv_reopen_commit = raw_reopen_commit,
+ .bdrv_reopen_abort = raw_reopen_abort,
.bdrv_close = raw_close,
.bdrv_create = raw_create,
.bdrv_co_discard = raw_co_discard,