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| author | sochin.jiang <sochin.jiang@huawei.com> | 2017-06-15 14:47:33 +0800 |
|---|---|---|
| committer | Max Reitz <mreitz@redhat.com> | 2017-06-26 14:54:46 +0200 |
| commit | 4172a00373b2c81374293becc02b16b7f8c76659 (patch) | |
| tree | fd448d57f39b13a48460c626bc6d3a49e6e7ccca | |
| parent | f5a5ca796932d04cb2a1cb9382a55f72795b3e06 (diff) | |
| download | qemu-4172a00373b2c81374293becc02b16b7f8c76659.tar.gz | |
fix: avoid an infinite loop or a dangling pointer problem in img_commit
img_commit could fall into an infinite loop calling run_block_job() if
its blockjob fails on any I/O error, fix this already known problem.
Signed-off-by: sochin.jiang <sochin.jiang@huawei.com>
Message-id: 1497509253-28941-1-git-send-email-sochin.jiang@huawei.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
| -rw-r--r-- | blockjob.c | 4 | ||||
| -rw-r--r-- | include/block/blockjob.h | 18 | ||||
| -rw-r--r-- | qemu-img.c | 20 |
3 files changed, 33 insertions, 9 deletions
diff --git a/blockjob.c b/blockjob.c index a0d7e29b83..70a78188b7 100644 --- a/blockjob.c +++ b/blockjob.c @@ -139,7 +139,7 @@ static void block_job_resume(BlockJob *job) block_job_enter(job); } -static void block_job_ref(BlockJob *job) +void block_job_ref(BlockJob *job) { ++job->refcnt; } @@ -148,7 +148,7 @@ static void block_job_attached_aio_context(AioContext *new_context, void *opaque); static void block_job_detach_aio_context(void *opaque); -static void block_job_unref(BlockJob *job) +void block_job_unref(BlockJob *job) { if (--job->refcnt == 0) { BlockDriverState *bs = blk_bs(job->blk); diff --git a/include/block/blockjob.h b/include/block/blockjob.h index 09c7c694b5..67c0968fa5 100644 --- a/include/block/blockjob.h +++ b/include/block/blockjob.h @@ -321,6 +321,24 @@ void block_job_iostatus_reset(BlockJob *job); BlockJobTxn *block_job_txn_new(void); /** + * block_job_ref: + * + * Add a reference to BlockJob refcnt, it will be decreased with + * block_job_unref, and then be freed if it comes to be the last + * reference. + */ +void block_job_ref(BlockJob *job); + +/** + * block_job_unref: + * + * Release a reference that was previously acquired with block_job_ref + * or block_job_create. If it's the last reference to the object, it will be + * freed. + */ +void block_job_unref(BlockJob *job); + +/** * block_job_txn_unref: * * Release a reference that was previously acquired with block_job_txn_add_job diff --git a/qemu-img.c b/qemu-img.c index 0ad698d7f1..e70d5155e4 100644 --- a/qemu-img.c +++ b/qemu-img.c @@ -887,22 +887,28 @@ static void common_block_job_cb(void *opaque, int ret) static void run_block_job(BlockJob *job, Error **errp) { AioContext *aio_context = blk_get_aio_context(job->blk); + int ret = 0; - /* FIXME In error cases, the job simply goes away and we access a dangling - * pointer below. */ aio_context_acquire(aio_context); + block_job_ref(job); do { aio_poll(aio_context, true); qemu_progress_print(job->len ? ((float)job->offset / job->len * 100.f) : 0.0f, 0); - } while (!job->ready); + } while (!job->ready && !job->completed); - block_job_complete_sync(job, errp); + if (!job->completed) { + ret = block_job_complete_sync(job, errp); + } else { + ret = job->ret; + } + block_job_unref(job); aio_context_release(aio_context); - /* A block job may finish instantaneously without publishing any progress, - * so just signal completion here */ - qemu_progress_print(100.f, 0); + /* publish completion progress only when success */ + if (!ret) { + qemu_progress_print(100.f, 0); + } } static int img_commit(int argc, char **argv) |