From 799c27e1243769a52fb3edc7e5b42f9f50c9fba6 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Sat, 18 Aug 2012 23:35:49 +0200 Subject: iscsi: fix races between task completion and abort This patch fixes two main issues with block/iscsi.c: 1) iscsi_task_mgmt_abort_task_async calls iscsi_scsi_task_cancel which was also directly called in iscsi_aio_cancel 2) a race between task completion and task abortion could happen cause the scsi_free_scsi_task were done before iscsi_schedule_bh has finished. To fix this, all the freeing of IscsiTasks and releasing of the AIOCBs is centralized in iscsi_bh_cb, independent of whether the SCSI command has completed or was cancelled. 3) iscsi_aio_cancel was not synchronously waiting for the end of the command. Signed-off-by: Paolo Bonzini (cherry picked from commit 1bd075f29ea6d11853475c7c42734595720c3ac6) Conflicts: block/iscsi.c Signed-off-by: Michael Roth --- block/iscsi.c | 52 ++++++++++++++++++++++++++++------------------------ 1 file changed, 28 insertions(+), 24 deletions(-) diff --git a/block/iscsi.c b/block/iscsi.c index 4584d54eb..c3d8db8b4 100644 --- a/block/iscsi.c +++ b/block/iscsi.c @@ -76,12 +76,20 @@ iscsi_bh_cb(void *p) acb->common.cb(acb->common.opaque, acb->status); } + if (acb->task != NULL) { + scsi_free_scsi_task(acb->task); + acb->task = NULL; + } + qemu_aio_release(acb); } static void iscsi_schedule_bh(IscsiAIOCB *acb) { + if (acb->bh) { + return; + } acb->bh = qemu_bh_new(iscsi_bh_cb, acb); qemu_bh_schedule(acb->bh); } @@ -91,6 +99,10 @@ static void iscsi_abort_task_cb(struct iscsi_context *iscsi, int status, void *command_data, void *private_data) { + IscsiAIOCB *acb = private_data; + + acb->status = -ECANCELED; + iscsi_schedule_bh(acb); } static void @@ -99,15 +111,19 @@ iscsi_aio_cancel(BlockDriverAIOCB *blockacb) IscsiAIOCB *acb = (IscsiAIOCB *)blockacb; IscsiLun *iscsilun = acb->iscsilun; - acb->common.cb(acb->common.opaque, -ECANCELED); + if (acb->status != -EINPROGRESS) { + return; + } + acb->canceled = 1; /* send a task mgmt call to the target to cancel the task on the target */ iscsi_task_mgmt_abort_task_async(iscsilun->iscsi, acb->task, - iscsi_abort_task_cb, NULL); + iscsi_abort_task_cb, acb); - /* then also cancel the task locally in libiscsi */ - iscsi_scsi_task_cancel(iscsilun->iscsi, acb->task); + while (acb->status == -EINPROGRESS) { + qemu_aio_wait(); + } } static AIOPool iscsi_aio_pool = { @@ -185,9 +201,6 @@ iscsi_aio_write16_cb(struct iscsi_context *iscsi, int status, g_free(acb->buf); if (acb->canceled != 0) { - qemu_aio_release(acb); - scsi_free_scsi_task(acb->task); - acb->task = NULL; return; } @@ -199,8 +212,6 @@ iscsi_aio_write16_cb(struct iscsi_context *iscsi, int status, } iscsi_schedule_bh(acb); - scsi_free_scsi_task(acb->task); - acb->task = NULL; } static int64_t sector_qemu2lun(int64_t sector, IscsiLun *iscsilun) @@ -229,6 +240,8 @@ iscsi_aio_writev(BlockDriverState *bs, int64_t sector_num, acb->qiov = qiov; acb->canceled = 0; + acb->bh = NULL; + acb->status = -EINPROGRESS; /* XXX we should pass the iovec to write16 to avoid the extra copy */ /* this will allow us to get rid of 'buf' completely */ @@ -287,9 +300,6 @@ iscsi_aio_read16_cb(struct iscsi_context *iscsi, int status, trace_iscsi_aio_read16_cb(iscsi, status, acb, acb->canceled); if (acb->canceled != 0) { - qemu_aio_release(acb); - scsi_free_scsi_task(acb->task); - acb->task = NULL; return; } @@ -301,8 +311,6 @@ iscsi_aio_read16_cb(struct iscsi_context *iscsi, int status, } iscsi_schedule_bh(acb); - scsi_free_scsi_task(acb->task); - acb->task = NULL; } static BlockDriverAIOCB * @@ -328,6 +336,8 @@ iscsi_aio_readv(BlockDriverState *bs, int64_t sector_num, acb->qiov = qiov; acb->canceled = 0; + acb->bh = NULL; + acb->status = -EINPROGRESS; acb->read_size = qemu_read_size; acb->buf = NULL; @@ -403,9 +413,6 @@ iscsi_synccache10_cb(struct iscsi_context *iscsi, int status, IscsiAIOCB *acb = opaque; if (acb->canceled != 0) { - qemu_aio_release(acb); - scsi_free_scsi_task(acb->task); - acb->task = NULL; return; } @@ -417,8 +424,6 @@ iscsi_synccache10_cb(struct iscsi_context *iscsi, int status, } iscsi_schedule_bh(acb); - scsi_free_scsi_task(acb->task); - acb->task = NULL; } static BlockDriverAIOCB * @@ -433,6 +438,8 @@ iscsi_aio_flush(BlockDriverState *bs, acb->iscsilun = iscsilun; acb->canceled = 0; + acb->bh = NULL; + acb->status = -EINPROGRESS; acb->task = iscsi_synchronizecache10_task(iscsi, iscsilun->lun, 0, 0, 0, 0, @@ -457,9 +464,6 @@ iscsi_unmap_cb(struct iscsi_context *iscsi, int status, IscsiAIOCB *acb = opaque; if (acb->canceled != 0) { - qemu_aio_release(acb); - scsi_free_scsi_task(acb->task); - acb->task = NULL; return; } @@ -471,8 +475,6 @@ iscsi_unmap_cb(struct iscsi_context *iscsi, int status, } iscsi_schedule_bh(acb); - scsi_free_scsi_task(acb->task); - acb->task = NULL; } static BlockDriverAIOCB * @@ -489,6 +491,8 @@ iscsi_aio_discard(BlockDriverState *bs, acb->iscsilun = iscsilun; acb->canceled = 0; + acb->bh = NULL; + acb->status = -EINPROGRESS; list[0].lba = sector_qemu2lun(sector_num, iscsilun); list[0].num = nb_sectors * BDRV_SECTOR_SIZE / iscsilun->block_size; -- cgit v1.2.3