On 07/30/2012 05:34 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> > > --- > Index: qemu/block/raw.c > =================================================================== > --- qemu.orig/block/raw.c > +++ qemu/block/raw.c > @@ -9,6 +9,22 @@ static int raw_open(BlockDriverState *bs > 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); > +} > +
I think the above should be stubs that do nothing (or, alternatively, are not present at all), if we have the reopen() do the bs->file reopen() (which is needed for qcow2 - see my comments for patch 1/9) > static int coroutine_fn raw_co_readv(BlockDriverState *bs, int64_t > sector_num, > int nb_sectors, QEMUIOVector *qiov) > { > @@ -113,6 +129,10 @@ static BlockDriver bdrv_raw = { > .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 > +++ qemu/block/raw-posix.c > @@ -140,8 +140,15 @@ typedef struct BDRVRawState { > #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 +290,117 @@ static int raw_open(BlockDriverState *bs > 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 */ > + bs->drv->bdrv_close(bs); > + ret = bs->drv->bdrv_file_open(bs, bs->filename, flags); This worries me, in that we close the BDS and then try to reopen it. At this point, if the bdrv_file_open() fails, we have no recovery mechanism. Maybe we could try to do something like a bdrv_file_open() into a new BDS before we close, followed by something akin to a bdrv_swap() / bdrv_append() if the new bdrv_file_open() was successful, and then do the close on the original. On failure, just abandon the new BDS. > + } > + 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 > { > @@ -735,6 +853,9 @@ static BlockDriver bdrv_file = { > .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, > >