The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y git checkout FETCH_HEAD git cherry-pick -x e5cfefa97bccf956ea0bb6464c1f6c84fd7a8d9f # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '167818241553113@kroah.com' --subject-prefix 'PATCH 5.15.y' HEAD^..

Possible dependencies:

e5cfefa97bcc ("block: fix scan partition for exclusively open device again") 0f77b29ad14e ("block: Revert "block: Do not reread partition table on exclusively open device"") 36369f46e917 ("block: Do not reread partition table on exclusively open device") 704b914f15fb ("blk-mq: move srcu from blk_mq_hw_ctx to request_queue") 2a904d00855f ("blk-mq: remove hctx_lock and hctx_unlock") 1e9c23034d7b ("blk-mq: move more plug handling from blk_mq_submit_bio into blk_add_rq_to_plug") 0c5bcc92d94a ("blk-mq: simplify the plug handling in blk_mq_submit_bio") e16e506ccd67 ("block: merge disk_scan_partitions and blkdev_reread_part") 95febeb61bf8 ("block: fix missing queue put in error path") b637108a4022 ("blk-mq: fix filesystem I/O request allocation") b131f2011115 ("blk-mq: rename blk_attempt_bio_merge") 9ef4d0209cba ("blk-mq: add one API for waiting until quiesce is done") 900e08075202 ("block: move queue enter logic into blk_mq_submit_bio()") c98cb5bbdab1 ("block: make bio_queue_enter() fast-path available inline") 71539717c105 ("block: split request allocation components into helpers") a1cb65377e70 ("blk-mq: only try to run plug merge if request has same queue with incoming bio") 781dd830ec4f ("block: move RQF_ELV setting into allocators") a2247f19ee1c ("block: Add independent access ranges support") e94f68527a35 ("block: kill extra rcu lock/unlock in queue enter") 179ae84f7ef5 ("block: clean up blk_mq_submit_bio() merging")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From e5cfefa97bccf956ea0bb6464c1f6c84fd7a8d9f Mon Sep 17 00:00:00 2001 From: Yu Kuai yukuai3@huawei.com Date: Fri, 17 Feb 2023 10:22:00 +0800 Subject: [PATCH] block: fix scan partition for exclusively open device again

As explained in commit 36369f46e917 ("block: Do not reread partition table on exclusively open device"), reread partition on the device that is exclusively opened by someone else is problematic.

This patch will make sure partition scan will only be proceed if current thread open the device exclusively, or the device is not opened exclusively, and in the later case, other scanners and exclusive openers will be blocked temporarily until partition scan is done.

Fixes: 10c70d95c0f2 ("block: remove the bd_openers checks in blk_drop_partitions") Cc: stable@vger.kernel.org Suggested-by: Jan Kara jack@suse.cz Signed-off-by: Yu Kuai yukuai3@huawei.com Reviewed-by: Christoph Hellwig hch@lst.de Link: https://lore.kernel.org/r/20230217022200.3092987-3-yukuai1@huaweicloud.com Signed-off-by: Jens Axboe axboe@kernel.dk

diff --git a/block/genhd.c b/block/genhd.c index 820e27d88cbf..c0a73cd76bb1 100644 --- a/block/genhd.c +++ b/block/genhd.c @@ -359,6 +359,7 @@ EXPORT_SYMBOL_GPL(disk_uevent); int disk_scan_partitions(struct gendisk *disk, fmode_t mode) { struct block_device *bdev; + int ret = 0;

if (disk->flags & (GENHD_FL_NO_PART | GENHD_FL_HIDDEN)) return -EINVAL; @@ -368,11 +369,27 @@ int disk_scan_partitions(struct gendisk *disk, fmode_t mode) return -EBUSY;

set_bit(GD_NEED_PART_SCAN, &disk->state); - bdev = blkdev_get_by_dev(disk_devt(disk), mode, NULL); + /* + * If the device is opened exclusively by current thread already, it's + * safe to scan partitons, otherwise, use bd_prepare_to_claim() to + * synchronize with other exclusive openers and other partition + * scanners. + */ + if (!(mode & FMODE_EXCL)) { + ret = bd_prepare_to_claim(disk->part0, disk_scan_partitions); + if (ret) + return ret; + } + + bdev = blkdev_get_by_dev(disk_devt(disk), mode & ~FMODE_EXCL, NULL); if (IS_ERR(bdev)) - return PTR_ERR(bdev); - blkdev_put(bdev, mode); - return 0; + ret = PTR_ERR(bdev); + else + blkdev_put(bdev, mode); + + if (!(mode & FMODE_EXCL)) + bd_abort_claiming(disk->part0, disk_scan_partitions); + return ret; }

/** @@ -494,6 +511,11 @@ int __must_check device_add_disk(struct device *parent, struct gendisk *disk, if (ret) goto out_unregister_bdi;

+ /* Make sure the first partition scan will be proceed */ + if (get_capacity(disk) && !(disk->flags & GENHD_FL_NO_PART) && + !test_bit(GD_SUPPRESS_PART_SCAN, &disk->state)) + set_bit(GD_NEED_PART_SCAN, &disk->state); + bdev_add(disk->part0, ddev->devt); if (get_capacity(disk)) disk_scan_partitions(disk, FMODE_READ); diff --git a/block/ioctl.c b/block/ioctl.c index 6dd49d877584..9c5f637ff153 100644 --- a/block/ioctl.c +++ b/block/ioctl.c @@ -528,7 +528,7 @@ static int blkdev_common_ioctl(struct block_device *bdev, fmode_t mode, return -EACCES; if (bdev_is_partition(bdev)) return -EINVAL; - return disk_scan_partitions(bdev->bd_disk, mode & ~FMODE_EXCL); + return disk_scan_partitions(bdev->bd_disk, mode); case BLKTRACESTART: case BLKTRACESTOP: case BLKTRACETEARDOWN: