* [Qemu-devel] [PATCH v3 0/2] linux-aio: fix two NULL pointer dereferences failure paths @ 2018-06-21 22:21 Nishanth Aravamudan 2018-06-21 22:21 ` [Qemu-devel] [PATCH v3 1/2] linux-aio: properly bubble up errors from initialization Nishanth Aravamudan 2018-06-21 22:21 ` [Qemu-devel] [PATCH v3 2/2] block/file-posix: reconfigure aio on iothread start Nishanth Aravamudan 0 siblings, 2 replies; 8+ messages in thread From: Nishanth Aravamudan @ 2018-06-21 22:21 UTC (permalink / raw) To: naravamudan Cc: Eric Blake, Kevin Wolf, John Snow, Max Reitz, Stefan Hajnoczi, Fam Zheng, Paolo Bonzini, qemu-block, qemu-devel laio_init() can fail for a couple of reasons, which will lead to a NULL pointer dereference in laio_attach_aio_context(), called from aio_get_linux_aio(). Test case 1: Set /proc/sys/fs/max-aio-nr to 0. Start a guest with an aio=native disk. Result: laio_init() returns NULL due to not being able to allocate any AIO contexts. This NULL is assigned to ctx->linux_aio and dereferenced in aio_get_linux_aio. Test case 2: Set /proc/sys/fs/max-aio-nr to 128. Start a guest with an aio=native disk and one in-use I/O thread. Result: laio_init() returns NULL due to not being able to allocate additional AIO contexts for the I/O thread. This NULL is assigned to ctx->linux_aio and dereferenced in aio_get_linux_aio. Thanks to Jon Snow, Eric Blake and Kevin Wolf for review comments on v1 and v2. Nishanth Aravamudan (2): linux-aio: properly bubble up errors from initialization file-posix: reconfigure aio on iothread start block/file-posix.c | 33 ++++++++++++++++++++++++++++----- block/linux-aio.c | 15 ++++++++++----- include/block/aio.h | 3 +++ include/block/raw-aio.h | 2 +- stubs/linux-aio.c | 2 +- util/async.c | 16 +++++++++++++--- 6 files changed, 56 insertions(+), 15 deletions(-) -- 2.17.1 ^ permalink raw reply [flat|nested] 8+ messages in thread
* [Qemu-devel] [PATCH v3 1/2] linux-aio: properly bubble up errors from initialization 2018-06-21 22:21 [Qemu-devel] [PATCH v3 0/2] linux-aio: fix two NULL pointer dereferences failure paths Nishanth Aravamudan @ 2018-06-21 22:21 ` Nishanth Aravamudan 2018-06-22 2:21 ` Fam Zheng 2018-06-21 22:21 ` [Qemu-devel] [PATCH v3 2/2] block/file-posix: reconfigure aio on iothread start Nishanth Aravamudan 1 sibling, 1 reply; 8+ messages in thread From: Nishanth Aravamudan @ 2018-06-21 22:21 UTC (permalink / raw) To: naravamudan Cc: Eric Blake, Kevin Wolf, John Snow, Max Reitz, Stefan Hajnoczi, Fam Zheng, Paolo Bonzini, qemu-block, qemu-devel laio_init() can fail for a couple of reasons, which will lead to a NULL pointer dereference in laio_attach_aio_context(). To solve this, add a aio_setup_linux_aio() function which is called early in raw_open_common. If this fails, propagate the error up. The signature of aio_get_linux_aio() was not modified, because it seems preferable to return the actual errno from the possible failing initialization calls. Add an assert that aio_get_linux_aio() cannot return NULL. Signed-off-by: Nishanth Aravamudan <naravamudan@digitalocean.com> --- Changes from v2 -> v3 (thanks to Eric Blake and Kevin Wolf for review): Use a boolean false rather than 0 in assignment to use_linux_aio. Drop ending '.' from error_report() calls. Fix typo in commit message (propogates -> propagates). Move aio_setup_linux_aio call to raw_open_common. Changes from v1 -> v2 (thanks to Kevin Wolf for review): Rather than affect virtio-scsi/blk at all, make all the changes internal to file-posix.c. Thanks to Kevin Wolf for the suggested change. block/file-posix.c | 17 ++++++++++++----- block/linux-aio.c | 15 ++++++++++----- include/block/aio.h | 3 +++ include/block/raw-aio.h | 2 +- stubs/linux-aio.c | 2 +- util/async.c | 16 +++++++++++++--- 6 files changed, 40 insertions(+), 15 deletions(-) diff --git a/block/file-posix.c b/block/file-posix.c index 07bb061fe4..6a1714d4a8 100644 --- a/block/file-posix.c +++ b/block/file-posix.c @@ -545,11 +545,18 @@ static int raw_open_common(BlockDriverState *bs, QDict *options, #ifdef CONFIG_LINUX_AIO /* Currently Linux does AIO only for files opened with O_DIRECT */ - if (s->use_linux_aio && !(s->open_flags & O_DIRECT)) { - error_setg(errp, "aio=native was specified, but it requires " - "cache.direct=on, which was not specified."); - ret = -EINVAL; - goto fail; + if (s->use_linux_aio) { + if (!(s->open_flags & O_DIRECT)) { + error_setg(errp, "aio=native was specified, but it requires " + "cache.direct=on, which was not specified."); + ret = -EINVAL; + goto fail; + } + ret = aio_setup_linux_aio(bdrv_get_aio_context(bs)); + if (ret != 0) { + error_setg(errp, "Unable to setup native AIO context."); + goto fail; + } } #else if (s->use_linux_aio) { diff --git a/block/linux-aio.c b/block/linux-aio.c index 88b8d55ec7..4d799f85fe 100644 --- a/block/linux-aio.c +++ b/block/linux-aio.c @@ -470,28 +470,33 @@ void laio_attach_aio_context(LinuxAioState *s, AioContext *new_context) qemu_laio_poll_cb); } -LinuxAioState *laio_init(void) +int laio_init(LinuxAioState **linux_aio) { + int rc; LinuxAioState *s; s = g_malloc0(sizeof(*s)); - if (event_notifier_init(&s->e, false) < 0) { + rc = event_notifier_init(&s->e, false); + if (rc < 0) { goto out_free_state; } - if (io_setup(MAX_EVENTS, &s->ctx) != 0) { + rc = io_setup(MAX_EVENTS, &s->ctx); + if (rc != 0) { goto out_close_efd; } ioq_init(&s->io_q); - return s; + *linux_aio = s; + return 0; out_close_efd: event_notifier_cleanup(&s->e); out_free_state: g_free(s); - return NULL; + *linux_aio = NULL; + return rc; } void laio_cleanup(LinuxAioState *s) diff --git a/include/block/aio.h b/include/block/aio.h index ae6f354e6c..8900516ac5 100644 --- a/include/block/aio.h +++ b/include/block/aio.h @@ -381,6 +381,9 @@ GSource *aio_get_g_source(AioContext *ctx); /* Return the ThreadPool bound to this AioContext */ struct ThreadPool *aio_get_thread_pool(AioContext *ctx); +/* Setup the LinuxAioState bound to this AioContext */ +int aio_setup_linux_aio(AioContext *ctx); + /* Return the LinuxAioState bound to this AioContext */ struct LinuxAioState *aio_get_linux_aio(AioContext *ctx); diff --git a/include/block/raw-aio.h b/include/block/raw-aio.h index 0e717fd475..81b90e5fc6 100644 --- a/include/block/raw-aio.h +++ b/include/block/raw-aio.h @@ -43,7 +43,7 @@ /* linux-aio.c - Linux native implementation */ #ifdef CONFIG_LINUX_AIO typedef struct LinuxAioState LinuxAioState; -LinuxAioState *laio_init(void); +int laio_init(LinuxAioState **linux_aio); void laio_cleanup(LinuxAioState *s); int coroutine_fn laio_co_submit(BlockDriverState *bs, LinuxAioState *s, int fd, uint64_t offset, QEMUIOVector *qiov, int type); diff --git a/stubs/linux-aio.c b/stubs/linux-aio.c index ed47bd443c..88ab927e35 100644 --- a/stubs/linux-aio.c +++ b/stubs/linux-aio.c @@ -21,7 +21,7 @@ void laio_attach_aio_context(LinuxAioState *s, AioContext *new_context) abort(); } -LinuxAioState *laio_init(void) +int laio_init(LinuxAioState **linux_aio) { abort(); } diff --git a/util/async.c b/util/async.c index 03f62787f2..ae88c931d0 100644 --- a/util/async.c +++ b/util/async.c @@ -323,12 +323,22 @@ ThreadPool *aio_get_thread_pool(AioContext *ctx) } #ifdef CONFIG_LINUX_AIO -LinuxAioState *aio_get_linux_aio(AioContext *ctx) +int aio_setup_linux_aio(AioContext *ctx) { + int rc; + rc = 0; if (!ctx->linux_aio) { - ctx->linux_aio = laio_init(); - laio_attach_aio_context(ctx->linux_aio, ctx); + rc = laio_init(&ctx->linux_aio); + if (rc == 0) { + laio_attach_aio_context(ctx->linux_aio, ctx); + } } + return rc; +} + +LinuxAioState *aio_get_linux_aio(AioContext *ctx) +{ + assert(ctx->linux_aio); return ctx->linux_aio; } #endif -- 2.17.1 ^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: [Qemu-devel] [PATCH v3 1/2] linux-aio: properly bubble up errors from initialization 2018-06-21 22:21 ` [Qemu-devel] [PATCH v3 1/2] linux-aio: properly bubble up errors from initialization Nishanth Aravamudan @ 2018-06-22 2:21 ` Fam Zheng 2018-06-22 17:12 ` Nishanth Aravamudan 0 siblings, 1 reply; 8+ messages in thread From: Fam Zheng @ 2018-06-22 2:21 UTC (permalink / raw) To: Nishanth Aravamudan Cc: Eric Blake, Kevin Wolf, John Snow, Max Reitz, Stefan Hajnoczi, Paolo Bonzini, qemu-block, qemu-devel On Thu, 06/21 15:21, Nishanth Aravamudan wrote: > laio_init() can fail for a couple of reasons, which will lead to a NULL > pointer dereference in laio_attach_aio_context(). > > To solve this, add a aio_setup_linux_aio() function which is called > early in raw_open_common. If this fails, propagate the error up. The > signature of aio_get_linux_aio() was not modified, because it seems > preferable to return the actual errno from the possible failing > initialization calls. > > Add an assert that aio_get_linux_aio() cannot return NULL. > > Signed-off-by: Nishanth Aravamudan <naravamudan@digitalocean.com> > --- > Changes from v2 -> v3 (thanks to Eric Blake and Kevin Wolf for review): > > Use a boolean false rather than 0 in assignment to use_linux_aio. > Drop ending '.' from error_report() calls. > Fix typo in commit message (propogates -> propagates). > Move aio_setup_linux_aio call to raw_open_common. > > Changes from v1 -> v2 (thanks to Kevin Wolf for review): > > Rather than affect virtio-scsi/blk at all, make all the changes internal > to file-posix.c. Thanks to Kevin Wolf for the suggested change. > > block/file-posix.c | 17 ++++++++++++----- > block/linux-aio.c | 15 ++++++++++----- > include/block/aio.h | 3 +++ > include/block/raw-aio.h | 2 +- > stubs/linux-aio.c | 2 +- > util/async.c | 16 +++++++++++++--- > 6 files changed, 40 insertions(+), 15 deletions(-) > > diff --git a/block/file-posix.c b/block/file-posix.c > index 07bb061fe4..6a1714d4a8 100644 > --- a/block/file-posix.c > +++ b/block/file-posix.c > @@ -545,11 +545,18 @@ static int raw_open_common(BlockDriverState *bs, QDict *options, > > #ifdef CONFIG_LINUX_AIO > /* Currently Linux does AIO only for files opened with O_DIRECT */ > - if (s->use_linux_aio && !(s->open_flags & O_DIRECT)) { > - error_setg(errp, "aio=native was specified, but it requires " > - "cache.direct=on, which was not specified."); > - ret = -EINVAL; > - goto fail; > + if (s->use_linux_aio) { > + if (!(s->open_flags & O_DIRECT)) { > + error_setg(errp, "aio=native was specified, but it requires " > + "cache.direct=on, which was not specified."); > + ret = -EINVAL; > + goto fail; > + } > + ret = aio_setup_linux_aio(bdrv_get_aio_context(bs)); > + if (ret != 0) { > + error_setg(errp, "Unable to setup native AIO context."); > + goto fail; > + } > } > #else > if (s->use_linux_aio) { > diff --git a/block/linux-aio.c b/block/linux-aio.c > index 88b8d55ec7..4d799f85fe 100644 > --- a/block/linux-aio.c > +++ b/block/linux-aio.c > @@ -470,28 +470,33 @@ void laio_attach_aio_context(LinuxAioState *s, AioContext *new_context) > qemu_laio_poll_cb); > } > > -LinuxAioState *laio_init(void) > +int laio_init(LinuxAioState **linux_aio) > { > + int rc; > LinuxAioState *s; > > s = g_malloc0(sizeof(*s)); > - if (event_notifier_init(&s->e, false) < 0) { > + rc = event_notifier_init(&s->e, false); > + if (rc < 0) { It would be nice if the error message could distinguish this error... > goto out_free_state; > } > > - if (io_setup(MAX_EVENTS, &s->ctx) != 0) { > + rc = io_setup(MAX_EVENTS, &s->ctx); > + if (rc != 0) { ... from this one. And it also makes sense to propagate the errno back with error_setg_errno. To do this, add an "Error **errp" parameter to the function and you can keep the return type (LinuxAioState *). > goto out_close_efd; > } > > ioq_init(&s->io_q); > > - return s; > + *linux_aio = s; > + return 0; > > out_close_efd: > event_notifier_cleanup(&s->e); > out_free_state: > g_free(s); > - return NULL; > + *linux_aio = NULL; > + return rc; > } > > void laio_cleanup(LinuxAioState *s) > diff --git a/include/block/aio.h b/include/block/aio.h > index ae6f354e6c..8900516ac5 100644 > --- a/include/block/aio.h > +++ b/include/block/aio.h > @@ -381,6 +381,9 @@ GSource *aio_get_g_source(AioContext *ctx); > /* Return the ThreadPool bound to this AioContext */ > struct ThreadPool *aio_get_thread_pool(AioContext *ctx); > > +/* Setup the LinuxAioState bound to this AioContext */ > +int aio_setup_linux_aio(AioContext *ctx); And this will then need "Error **errp" as well. > + > /* Return the LinuxAioState bound to this AioContext */ > struct LinuxAioState *aio_get_linux_aio(AioContext *ctx); > > diff --git a/include/block/raw-aio.h b/include/block/raw-aio.h > index 0e717fd475..81b90e5fc6 100644 > --- a/include/block/raw-aio.h > +++ b/include/block/raw-aio.h > @@ -43,7 +43,7 @@ > /* linux-aio.c - Linux native implementation */ > #ifdef CONFIG_LINUX_AIO > typedef struct LinuxAioState LinuxAioState; > -LinuxAioState *laio_init(void); > +int laio_init(LinuxAioState **linux_aio); > void laio_cleanup(LinuxAioState *s); > int coroutine_fn laio_co_submit(BlockDriverState *bs, LinuxAioState *s, int fd, > uint64_t offset, QEMUIOVector *qiov, int type); > diff --git a/stubs/linux-aio.c b/stubs/linux-aio.c > index ed47bd443c..88ab927e35 100644 > --- a/stubs/linux-aio.c > +++ b/stubs/linux-aio.c > @@ -21,7 +21,7 @@ void laio_attach_aio_context(LinuxAioState *s, AioContext *new_context) > abort(); > } > > -LinuxAioState *laio_init(void) > +int laio_init(LinuxAioState **linux_aio) > { > abort(); > } > diff --git a/util/async.c b/util/async.c > index 03f62787f2..ae88c931d0 100644 > --- a/util/async.c > +++ b/util/async.c > @@ -323,12 +323,22 @@ ThreadPool *aio_get_thread_pool(AioContext *ctx) > } > > #ifdef CONFIG_LINUX_AIO > -LinuxAioState *aio_get_linux_aio(AioContext *ctx) > +int aio_setup_linux_aio(AioContext *ctx) > { > + int rc; > + rc = 0; > if (!ctx->linux_aio) { > - ctx->linux_aio = laio_init(); > - laio_attach_aio_context(ctx->linux_aio, ctx); > + rc = laio_init(&ctx->linux_aio); > + if (rc == 0) { > + laio_attach_aio_context(ctx->linux_aio, ctx); > + } > } > + return rc; > +} > + > +LinuxAioState *aio_get_linux_aio(AioContext *ctx) > +{ > + assert(ctx->linux_aio); > return ctx->linux_aio; > } > #endif > -- > 2.17.1 > Fam ^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [Qemu-devel] [PATCH v3 1/2] linux-aio: properly bubble up errors from initialization 2018-06-22 2:21 ` Fam Zheng @ 2018-06-22 17:12 ` Nishanth Aravamudan 0 siblings, 0 replies; 8+ messages in thread From: Nishanth Aravamudan @ 2018-06-22 17:12 UTC (permalink / raw) To: Fam Zheng Cc: Eric Blake, Kevin Wolf, John Snow, Max Reitz, Stefan Hajnoczi, Paolo Bonzini, qemu-block, qemu-devel On 22.06.2018 [10:21:19 +0800], Fam Zheng wrote: > On Thu, 06/21 15:21, Nishanth Aravamudan wrote: > > laio_init() can fail for a couple of reasons, which will lead to a NULL > > pointer dereference in laio_attach_aio_context(). > > > > To solve this, add a aio_setup_linux_aio() function which is called > > early in raw_open_common. If this fails, propagate the error up. The > > signature of aio_get_linux_aio() was not modified, because it seems > > preferable to return the actual errno from the possible failing > > initialization calls. > > > > Add an assert that aio_get_linux_aio() cannot return NULL. > > > > Signed-off-by: Nishanth Aravamudan <naravamudan@digitalocean.com> > > --- > > Changes from v2 -> v3 (thanks to Eric Blake and Kevin Wolf for review): > > > > Use a boolean false rather than 0 in assignment to use_linux_aio. > > Drop ending '.' from error_report() calls. > > Fix typo in commit message (propogates -> propagates). > > Move aio_setup_linux_aio call to raw_open_common. > > > > Changes from v1 -> v2 (thanks to Kevin Wolf for review): > > > > Rather than affect virtio-scsi/blk at all, make all the changes internal > > to file-posix.c. Thanks to Kevin Wolf for the suggested change. > > > > block/file-posix.c | 17 ++++++++++++----- > > block/linux-aio.c | 15 ++++++++++----- > > include/block/aio.h | 3 +++ > > include/block/raw-aio.h | 2 +- > > stubs/linux-aio.c | 2 +- > > util/async.c | 16 +++++++++++++--- > > 6 files changed, 40 insertions(+), 15 deletions(-) > > > > diff --git a/block/file-posix.c b/block/file-posix.c > > index 07bb061fe4..6a1714d4a8 100644 > > --- a/block/file-posix.c > > +++ b/block/file-posix.c > > @@ -545,11 +545,18 @@ static int raw_open_common(BlockDriverState *bs, QDict *options, > > > > #ifdef CONFIG_LINUX_AIO > > /* Currently Linux does AIO only for files opened with O_DIRECT */ > > - if (s->use_linux_aio && !(s->open_flags & O_DIRECT)) { > > - error_setg(errp, "aio=native was specified, but it requires " > > - "cache.direct=on, which was not specified."); > > - ret = -EINVAL; > > - goto fail; > > + if (s->use_linux_aio) { > > + if (!(s->open_flags & O_DIRECT)) { > > + error_setg(errp, "aio=native was specified, but it requires " > > + "cache.direct=on, which was not specified."); > > + ret = -EINVAL; > > + goto fail; > > + } > > + ret = aio_setup_linux_aio(bdrv_get_aio_context(bs)); > > + if (ret != 0) { > > + error_setg(errp, "Unable to setup native AIO context."); > > + goto fail; > > + } > > } > > #else > > if (s->use_linux_aio) { > > diff --git a/block/linux-aio.c b/block/linux-aio.c > > index 88b8d55ec7..4d799f85fe 100644 > > --- a/block/linux-aio.c > > +++ b/block/linux-aio.c > > @@ -470,28 +470,33 @@ void laio_attach_aio_context(LinuxAioState *s, AioContext *new_context) > > qemu_laio_poll_cb); > > } > > > > -LinuxAioState *laio_init(void) > > +int laio_init(LinuxAioState **linux_aio) > > { > > + int rc; > > LinuxAioState *s; > > > > s = g_malloc0(sizeof(*s)); > > - if (event_notifier_init(&s->e, false) < 0) { > > + rc = event_notifier_init(&s->e, false); > > + if (rc < 0) { > > It would be nice if the error message could distinguish this error... > > > goto out_free_state; > > } > > > > - if (io_setup(MAX_EVENTS, &s->ctx) != 0) { > > + rc = io_setup(MAX_EVENTS, &s->ctx); > > + if (rc != 0) { > > ... from this one. And it also makes sense to propagate the errno back with > error_setg_errno. > > To do this, add an "Error **errp" parameter to the function and you > can keep the return type (LinuxAioState *). Thank you for this suggestion! I will send out a v4 with this and your other feedback integrated. -Nish ^ permalink raw reply [flat|nested] 8+ messages in thread
* [Qemu-devel] [PATCH v3 2/2] block/file-posix: reconfigure aio on iothread start 2018-06-21 22:21 [Qemu-devel] [PATCH v3 0/2] linux-aio: fix two NULL pointer dereferences failure paths Nishanth Aravamudan 2018-06-21 22:21 ` [Qemu-devel] [PATCH v3 1/2] linux-aio: properly bubble up errors from initialization Nishanth Aravamudan @ 2018-06-21 22:21 ` Nishanth Aravamudan 2018-06-22 2:25 ` Fam Zheng 1 sibling, 1 reply; 8+ messages in thread From: Nishanth Aravamudan @ 2018-06-21 22:21 UTC (permalink / raw) To: naravamudan Cc: Eric Blake, Kevin Wolf, John Snow, Max Reitz, Stefan Hajnoczi, Fam Zheng, Paolo Bonzini, qemu-block, qemu-devel When the AioContext changes, we need to associate a LinuxAioState with the new AioContext. Use the bdrv_attach_aio_context callback and call the new aio_setup_linux_aio(), which will allocate a new AioContext if needed, and return errors on failures. If it fails for any reason, fallback to threaded AIO with an error message, as the device is already in-use by the guest. Signed-off-by: Nishanth Aravamudan <naravamudan@digitalocean.com> --- Note this patch didn't exist in v2, but is a result of feedback to that posting. block/file-posix.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/block/file-posix.c b/block/file-posix.c index 6a1714d4a8..ce24950acf 100644 --- a/block/file-posix.c +++ b/block/file-posix.c @@ -1730,6 +1730,21 @@ static BlockAIOCB *raw_aio_flush(BlockDriverState *bs, return paio_submit(bs, s->fd, 0, NULL, 0, cb, opaque, QEMU_AIO_FLUSH); } +static void raw_aio_attach_aio_context(BlockDriverState *bs, + AioContext *new_context) +{ +#ifdef CONFIG_LINUX_AIO + BDRVRawState *s = bs->opaque; + if (s->use_linux_aio) { + if (aio_setup_linux_aio(new_context) != 0) { + error_report("Unable to use native AIO, falling back to " + "thread pool"); + s->use_linux_aio = false; + } + } +#endif +} + static void raw_close(BlockDriverState *bs) { BDRVRawState *s = bs->opaque; @@ -2608,6 +2623,7 @@ BlockDriver bdrv_file = { .bdrv_refresh_limits = raw_refresh_limits, .bdrv_io_plug = raw_aio_plug, .bdrv_io_unplug = raw_aio_unplug, + .bdrv_attach_aio_context = raw_aio_attach_aio_context, .bdrv_truncate = raw_truncate, .bdrv_getlength = raw_getlength, -- 2.17.1 ^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: [Qemu-devel] [PATCH v3 2/2] block/file-posix: reconfigure aio on iothread start 2018-06-21 22:21 ` [Qemu-devel] [PATCH v3 2/2] block/file-posix: reconfigure aio on iothread start Nishanth Aravamudan @ 2018-06-22 2:25 ` Fam Zheng 2018-06-22 9:02 ` Kevin Wolf 0 siblings, 1 reply; 8+ messages in thread From: Fam Zheng @ 2018-06-22 2:25 UTC (permalink / raw) To: Nishanth Aravamudan Cc: Eric Blake, Kevin Wolf, John Snow, Max Reitz, Stefan Hajnoczi, Paolo Bonzini, qemu-block, qemu-devel On Thu, 06/21 15:21, Nishanth Aravamudan wrote: > When the AioContext changes, we need to associate a LinuxAioState with > the new AioContext. Use the bdrv_attach_aio_context callback and call > the new aio_setup_linux_aio(), which will allocate a new AioContext if > needed, and return errors on failures. If it fails for any reason, > fallback to threaded AIO with an error message, as the device is already > in-use by the guest. > > Signed-off-by: Nishanth Aravamudan <naravamudan@digitalocean.com> > --- > Note this patch didn't exist in v2, but is a result of feedback to that > posting. This should be squashed into patch 1, no? Fam ^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [Qemu-devel] [PATCH v3 2/2] block/file-posix: reconfigure aio on iothread start 2018-06-22 2:25 ` Fam Zheng @ 2018-06-22 9:02 ` Kevin Wolf 2018-06-22 17:12 ` Nishanth Aravamudan 0 siblings, 1 reply; 8+ messages in thread From: Kevin Wolf @ 2018-06-22 9:02 UTC (permalink / raw) To: Fam Zheng Cc: Nishanth Aravamudan, Eric Blake, John Snow, Max Reitz, Stefan Hajnoczi, Paolo Bonzini, qemu-block, qemu-devel Am 22.06.2018 um 04:25 hat Fam Zheng geschrieben: > On Thu, 06/21 15:21, Nishanth Aravamudan wrote: > > When the AioContext changes, we need to associate a LinuxAioState with > > the new AioContext. Use the bdrv_attach_aio_context callback and call > > the new aio_setup_linux_aio(), which will allocate a new AioContext if > > needed, and return errors on failures. If it fails for any reason, > > fallback to threaded AIO with an error message, as the device is already > > in-use by the guest. > > > > Signed-off-by: Nishanth Aravamudan <naravamudan@digitalocean.com> > > --- > > Note this patch didn't exist in v2, but is a result of feedback to that > > posting. > > This should be squashed into patch 1, no? Yes, without it, patch 1 is incorrect. Specifically, at least the assertion in aio_get_linux_aio() won't hold true without it. Kevin ^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [Qemu-devel] [PATCH v3 2/2] block/file-posix: reconfigure aio on iothread start 2018-06-22 9:02 ` Kevin Wolf @ 2018-06-22 17:12 ` Nishanth Aravamudan 0 siblings, 0 replies; 8+ messages in thread From: Nishanth Aravamudan @ 2018-06-22 17:12 UTC (permalink / raw) To: Kevin Wolf Cc: Fam Zheng, Eric Blake, John Snow, Max Reitz, Stefan Hajnoczi, Paolo Bonzini, qemu-block, qemu-devel On 22.06.2018 [11:02:06 +0200], Kevin Wolf wrote: > Am 22.06.2018 um 04:25 hat Fam Zheng geschrieben: > > On Thu, 06/21 15:21, Nishanth Aravamudan wrote: > > > When the AioContext changes, we need to associate a LinuxAioState with > > > the new AioContext. Use the bdrv_attach_aio_context callback and call > > > the new aio_setup_linux_aio(), which will allocate a new AioContext if > > > needed, and return errors on failures. If it fails for any reason, > > > fallback to threaded AIO with an error message, as the device is already > > > in-use by the guest. > > > > > > Signed-off-by: Nishanth Aravamudan <naravamudan@digitalocean.com> > > > --- > > > Note this patch didn't exist in v2, but is a result of feedback to that > > > posting. > > > > This should be squashed into patch 1, no? > > Yes, without it, patch 1 is incorrect. Specifically, at least the > assertion in aio_get_linux_aio() won't hold true without it. Yes, you are right! Sorry about that. I'll send a v4 today. -Nish ^ permalink raw reply [flat|nested] 8+ messages in thread
end of thread, other threads:[~2018-06-22 17:12 UTC | newest] Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2018-06-21 22:21 [Qemu-devel] [PATCH v3 0/2] linux-aio: fix two NULL pointer dereferences failure paths Nishanth Aravamudan 2018-06-21 22:21 ` [Qemu-devel] [PATCH v3 1/2] linux-aio: properly bubble up errors from initialization Nishanth Aravamudan 2018-06-22 2:21 ` Fam Zheng 2018-06-22 17:12 ` Nishanth Aravamudan 2018-06-21 22:21 ` [Qemu-devel] [PATCH v3 2/2] block/file-posix: reconfigure aio on iothread start Nishanth Aravamudan 2018-06-22 2:25 ` Fam Zheng 2018-06-22 9:02 ` Kevin Wolf 2018-06-22 17:12 ` Nishanth Aravamudan
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