block: drain file system I/O on del_gendisk

Instead of delaying draining of file system I/O related items like the
blk-qos queues, the integrity read workqueue and timeouts only when the
request_queue is removed, do that when del_gendisk is called.  This is
important for SCSI where the upper level drivers that control the gendisk
are separate entities, and the disk can be freed much earlier than the
request_queue, or can even be unbound without tearing down the queue.

Fixes: c73c5e0d3ea0 ("block: move the bdi from the request_queue to the gendisk")
Reported-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Darrick J. Wong <djwong@kernel.org>
Link: https://lore.kernel.org/r/20210929071241.934472-5-hch@lst.de
Tested-by: Yi Zhang <yi.zhang@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/block/blk-core.c b/block/blk-core.c
index 43f5da707d8e3286a8752e8e095e65f717f45566..4d8f5fe915887e1dc17f4ebe58482293945edddd 100644 (file)
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -49,7 +49,6 @@
 #include "blk-mq.h"
 #include "blk-mq-sched.h"
 #include "blk-pm.h"
-#include "blk-rq-qos.h"
 
 struct dentry *blk_debugfs_root;
 
@@ -337,23 +336,25 @@ void blk_put_queue(struct request_queue *q)
 }
 EXPORT_SYMBOL(blk_put_queue);
 
-void blk_set_queue_dying(struct request_queue *q)
+void blk_queue_start_drain(struct request_queue *q)
 {
-       blk_queue_flag_set(QUEUE_FLAG_DYING, q);
-
        /*
         * When queue DYING flag is set, we need to block new req
         * entering queue, so we call blk_freeze_queue_start() to
         * prevent I/O from crossing blk_queue_enter().
         */
        blk_freeze_queue_start(q);
-
        if (queue_is_mq(q))
                blk_mq_wake_waiters(q);
-
        /* Make blk_queue_enter() reexamine the DYING flag. */
        wake_up_all(&q->mq_freeze_wq);
 }
+
+void blk_set_queue_dying(struct request_queue *q)
+{
+       blk_queue_flag_set(QUEUE_FLAG_DYING, q);
+       blk_queue_start_drain(q);
+}
 EXPORT_SYMBOL_GPL(blk_set_queue_dying);
 
 /**
@@ -385,13 +386,8 @@ void blk_cleanup_queue(struct request_queue *q)
         */
        blk_freeze_queue(q);
 
-       rq_qos_exit(q);
-
        blk_queue_flag_set(QUEUE_FLAG_DEAD, q);
 
-       /* for synchronous bio-based driver finish in-flight integrity i/o */
-       blk_flush_integrity();
-
        blk_sync_queue(q);
        if (queue_is_mq(q))
                blk_mq_exit_queue(q);
@@ -474,11 +470,12 @@ int blk_queue_enter(struct request_queue *q, blk_mq_req_flags_t flags)
 
 static inline int bio_queue_enter(struct bio *bio)
 {
-       struct request_queue *q = bio->bi_bdev->bd_disk->queue;
+       struct gendisk *disk = bio->bi_bdev->bd_disk;
+       struct request_queue *q = disk->queue;
 
        while (!blk_try_enter_queue(q, false)) {
                if (bio->bi_opf & REQ_NOWAIT) {
-                       if (blk_queue_dying(q))
+                       if (test_bit(GD_DEAD, &disk->state))
                                goto dead;
                        bio_wouldblock_error(bio);
                        return -EBUSY;
@@ -495,8 +492,8 @@ static inline int bio_queue_enter(struct bio *bio)
                wait_event(q->mq_freeze_wq,
                           (!q->mq_freeze_depth &&
                            blk_pm_resume_queue(false, q)) ||
-                          blk_queue_dying(q));
-               if (blk_queue_dying(q))
+                          test_bit(GD_DEAD, &disk->state));
+               if (test_bit(GD_DEAD, &disk->state))
                        goto dead;
        }
 

diff --git a/block/blk.h b/block/blk.h
index 7d2a0ba7ed21da27662f712ebdc69905215814fc..e2ed2257709ae4cb92efb710c8241dd27fd411ea 100644 (file)
--- a/block/blk.h
+++ b/block/blk.h
@@ -51,6 +51,7 @@ struct blk_flush_queue *blk_alloc_flush_queue(int node, int cmd_size,
 void blk_free_flush_queue(struct blk_flush_queue *q);
 
 void blk_freeze_queue(struct request_queue *q);
+void blk_queue_start_drain(struct request_queue *q);
 
 #define BIO_INLINE_VECS 4
 struct bio_vec *bvec_alloc(mempool_t *pool, unsigned short *nr_vecs,

diff --git a/block/genhd.c b/block/genhd.c
index 496e8458c3574343807bd25459bca4bfd729d0fd..1fe816be9bcdbba63b1d9ac9946b8f02a270ce40 100644 (file)
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -26,6 +26,7 @@
 #include <linux/badblocks.h>
 
 #include "blk.h"
+#include "blk-rq-qos.h"
 
 static struct kobject *block_depr;
 
@@ -559,6 +560,8 @@ EXPORT_SYMBOL(device_add_disk);
  */
 void del_gendisk(struct gendisk *disk)
 {
+       struct request_queue *q = disk->queue;
+
        might_sleep();
 
        if (WARN_ON_ONCE(!disk_live(disk) && !(disk->flags & GENHD_FL_HIDDEN)))
@@ -575,8 +578,26 @@ void del_gendisk(struct gendisk *disk)
        fsync_bdev(disk->part0);
        __invalidate_device(disk->part0, true);
 
+       /*
+        * Fail any new I/O.
+        */
+       set_bit(GD_DEAD, &disk->state);
        set_capacity(disk, 0);
 
+       /*
+        * Prevent new I/O from crossing bio_queue_enter().
+        */
+       blk_queue_start_drain(q);
+       blk_mq_freeze_queue_wait(q);
+
+       rq_qos_exit(q);
+       blk_sync_queue(q);
+       blk_flush_integrity();
+       /*
+        * Allow using passthrough request again after the queue is torn down.
+        */
+       blk_mq_unfreeze_queue(q);
+
        if (!(disk->flags & GENHD_FL_HIDDEN)) {
                sysfs_remove_link(&disk_to_dev(disk)->kobj, "bdi");
 

diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index c68d83c87f83fc9c0e3e946c5ccbd895e4d97724..0f5315c2b5a346eb716a77d0ba03e87138f363b3 100644 (file)
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -149,6 +149,7 @@ struct gendisk {
        unsigned long state;
 #define GD_NEED_PART_SCAN              0
 #define GD_READ_ONLY                   1
+#define GD_DEAD                                2
 
        struct mutex open_mutex;        /* open/close mutex */
        unsigned open_partitions;       /* number of open partitions */