| Message ID | 20210104130659.22511-2-minwoo.im.dev@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | block: fix I/O errors in BLKRRPART | expand |
On Mon, Jan 04, 2021 at 10:06:59PM +0900, Minwoo Im wrote: > + if (q->backing_dev_info && q->backing_dev_info->owner && > + limits->logical_block_size != size) { > + bdev = blkdev_get_no_open(q->backing_dev_info->owner->devt); > + bdev->bd_disk->flags |= GENHD_FL_BLOCK_SIZE_CHANGED; > + blkdev_put_no_open(bdev); > + } We really need the backpointer from the queue to the gendisk I've wanted to add for a while. Can we at least restrict this to a live gendisk? Also I think the size change flag should go into the ->state field and use the atomic bitops helpers to avoid concurrency problems.
On Mon, Jan 04, 2021 at 06:11:08PM +0100, Christoph Hellwig wrote: > On Mon, Jan 04, 2021 at 10:06:59PM +0900, Minwoo Im wrote: > > + if (q->backing_dev_info && q->backing_dev_info->owner && > > + limits->logical_block_size != size) { > > + bdev = blkdev_get_no_open(q->backing_dev_info->owner->devt); > > + bdev->bd_disk->flags |= GENHD_FL_BLOCK_SIZE_CHANGED; > > + blkdev_put_no_open(bdev); > > + } > > We really need the backpointer from the queue to the gendisk I've wanted > to add for a while. Can we at least restrict this to a live gendisk? Alternatively we could make this request_queue QUEUE* flag for now.
Hello Christoph, Thanks for your review. On 21-01-04 18:11:41, Christoph Hellwig wrote: > On Mon, Jan 04, 2021 at 06:11:08PM +0100, Christoph Hellwig wrote: > > On Mon, Jan 04, 2021 at 10:06:59PM +0900, Minwoo Im wrote: > > > + if (q->backing_dev_info && q->backing_dev_info->owner && > > > + limits->logical_block_size != size) { > > > + bdev = blkdev_get_no_open(q->backing_dev_info->owner->devt); > > > + bdev->bd_disk->flags |= GENHD_FL_BLOCK_SIZE_CHANGED; > > > + blkdev_put_no_open(bdev); > > > + } > > > > We really need the backpointer from the queue to the gendisk I've wanted > > to add for a while. Can we at least restrict this to a live gendisk? It was a point that I really would like to ask by RFC whether we can have backpointer to the gendisk from the request_queue. And I'd like to have it to simplify this routine and for future usages also. I will restrict this one by checking GENHD_FL_UP flag from the gendisk for the next patch. > > Alternatively we could make this request_queue QUEUE* flag for now. As this patch rejects I/O from the block layer partition code, can we have this flag in gendisk rather than request_queue ? Thanks,
On Tue, Jan 05, 2021 at 10:04:56AM +0900, Minwoo Im wrote: > It was a point that I really would like to ask by RFC whether we can > have backpointer to the gendisk from the request_queue. And I'd like to > have it to simplify this routine and for future usages also. I think it is the right thing to do, at least mid-term, although I don't want to enforce the burden on you right now. > I will restrict this one by checking GENHD_FL_UP flag from the gendisk > for the next patch. > > > > > Alternatively we could make this request_queue QUEUE* flag for now. > > As this patch rejects I/O from the block layer partition code, can we > have this flag in gendisk rather than request_queue ? For now we can as the request_queue is required. I have some plans to clean up this area, but just using a request_queue flag for now is probably the simplest, even if it means more work for me later.
Hello, On 21-01-05 08:50:09, Christoph Hellwig wrote: > On Tue, Jan 05, 2021 at 10:04:56AM +0900, Minwoo Im wrote: > > It was a point that I really would like to ask by RFC whether we can > > have backpointer to the gendisk from the request_queue. And I'd like to > > have it to simplify this routine and for future usages also. > > I think it is the right thing to do, at least mid-term, although I > don't want to enforce the burden on you right now. > > > I will restrict this one by checking GENHD_FL_UP flag from the gendisk > > for the next patch. > > > > > > > > Alternatively we could make this request_queue QUEUE* flag for now. > > > > As this patch rejects I/O from the block layer partition code, can we > > have this flag in gendisk rather than request_queue ? > > For now we can as the request_queue is required. I have some plans to > clean up this area, but just using a request_queue flag for now is > probably the simplest, even if it means more work for me later. Please let me prepare the next quick fix for this issue with request_queue flag. Thanks!
diff --git a/block/blk-settings.c b/block/blk-settings.c index 43990b1d148b..84136ea4e2a4 100644 --- a/block/blk-settings.c +++ b/block/blk-settings.c @@ -328,6 +328,14 @@ EXPORT_SYMBOL(blk_queue_max_segment_size); void blk_queue_logical_block_size(struct request_queue *q, unsigned int size) { struct queue_limits *limits = &q->limits; + struct block_device *bdev; + + if (q->backing_dev_info && q->backing_dev_info->owner && + limits->logical_block_size != size) { + bdev = blkdev_get_no_open(q->backing_dev_info->owner->devt); + bdev->bd_disk->flags |= GENHD_FL_BLOCK_SIZE_CHANGED; + blkdev_put_no_open(bdev); + } limits->logical_block_size = size; diff --git a/block/partitions/core.c b/block/partitions/core.c index e7d776db803b..5a0330c1b6f9 100644 --- a/block/partitions/core.c +++ b/block/partitions/core.c @@ -618,6 +618,17 @@ int blk_add_partitions(struct gendisk *disk, struct block_device *bdev) if (!disk_part_scan_enabled(disk)) return 0; + /* + * Reject to check partition information if block size has been changed + * in the runtime. If block size of a block device has been changed, + * the file descriptor should be opened agian to update the blkbits. + */ + if (disk->flags & GENHD_FL_BLOCK_SIZE_CHANGED) { + pr_warn("%s: rejecting checking partition. fd should be opened again.\n", + disk->disk_name); + return -EBADFD; + } + state = check_partition(disk, bdev); if (!state) return 0; diff --git a/fs/block_dev.c b/fs/block_dev.c index 9293045e128c..c996de3d6084 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -131,6 +131,12 @@ EXPORT_SYMBOL(truncate_bdev_range); static void set_init_blocksize(struct block_device *bdev) { bdev->bd_inode->i_blkbits = blksize_bits(bdev_logical_block_size(bdev)); + + /* + * Allow I/O commands for this block device. We can say that this + * block device has been set to a proper block size. + */ + bdev->bd_disk->flags &= ~GENHD_FL_BLOCK_SIZE_CHANGED; } int set_blocksize(struct block_device *bdev, int size) diff --git a/include/linux/genhd.h b/include/linux/genhd.h index 809aaa32d53c..0e0e24917003 100644 --- a/include/linux/genhd.h +++ b/include/linux/genhd.h @@ -103,6 +103,7 @@ struct partition_meta_info { #define GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE 0x0100 #define GENHD_FL_NO_PART_SCAN 0x0200 #define GENHD_FL_HIDDEN 0x0400 +#define GENHD_FL_BLOCK_SIZE_CHANGED 0x0800 enum { DISK_EVENT_MEDIA_CHANGE = 1 << 0, /* media changed */
This patch fixes I/O errors during BLKRRPART ioctl() behavior right after format operation that changed logical block size of the block device with a same file descriptor opened. This issue can be easily reproduced with a single format command in case of NVMe (logical block size 512B to 4096B). nvme format /dev/nvme0n1 --lbaf=1 --force This is because the application, nvme-cli format subcommand issues an admin command followed by BLKRRPART ioctl to re-read partition information without closing the file descriptor. If file descriptor stays opened, __blkdev_get() will not be invoked at all even logical block size has been changed. It will cause I/O errors with invalid Read operations during the BLKRRPART ioctl due to i_blkbits mismatch. The invalid operations in BLKRRPART happens with under-flowed Number of LBA(NLB) values 0xffff(65535) because i_blkbits is still set to 9 even the logical block size has been updated to 4096. The BLKRRPART will lead buffer_head to hold 512B data which is less than the logical lock size of the block device. The root cause, which is because i_blkbits of inode of the block device is not updated, can be solved easily by re-opening file descriptor again from application. But, that's just for application's business and kernel should reject invalid Read operations during the BLKRRPART ioctl. This patch rejects I/O from the path of add_partitions() to avoid issuing invalid Read operations to device. It also sets a flag to gendisk in blk_queue_logical_block_size to minimize caller-side updates. Signed-off-by: Minwoo Im <minwoo.im.dev@gmail.com> --- block/blk-settings.c | 8 ++++++++ block/partitions/core.c | 11 +++++++++++ fs/block_dev.c | 6 ++++++ include/linux/genhd.h | 1 + 4 files changed, 26 insertions(+)