[PATCH AUTOSEL 6.12 16/19] md/raid1: Handle bio_split() errors

[PATCH AUTOSEL 6.12 16/19] md/raid1: Handle bio_split() errors

[Sasha Levin]

From: John Garry <john.g.garry@oracle.com>

[ Upstream commit b1a7ad8b5c4fa28325ee7b369a2d545d3e16ccde ]

Add proper bio_split() error handling. For any error, call
raid_end_bio_io() and return.

For the case of an in the write path, we need to undo the increment in
the rdev pending count and NULLify the r1_bio->bios[] pointers.

For read path failure, we need to undo rdev pending count increment from
the earlier read_balance() call.

Reviewed-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: John Garry <john.g.garry@oracle.com>
Link: https://lore.kernel.org/r/20241111112150.3756529-6-john.g.garry@oracle.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/md/raid1.c | 33 +++++++++++++++++++++++++++++++--
 1 file changed, 31 insertions(+), 2 deletions(-)

diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index 6c9d24203f39f..7e023e9303c8a 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -1322,7 +1322,7 @@ static void raid1_read_request(struct mddev *mddev, struct bio *bio,
 	const enum req_op op = bio_op(bio);
 	const blk_opf_t do_sync = bio->bi_opf & REQ_SYNC;
 	int max_sectors;
-	int rdisk;
+	int rdisk, error;
 	bool r1bio_existed = !!r1_bio;
 
 	/*
@@ -1383,6 +1383,11 @@ static void raid1_read_request(struct mddev *mddev, struct bio *bio,
 	if (max_sectors < bio_sectors(bio)) {
 		struct bio *split = bio_split(bio, max_sectors,
 					      gfp, &conf->bio_split);
+
+		if (IS_ERR(split)) {
+			error = PTR_ERR(split);
+			goto err_handle;
+		}
 		bio_chain(split, bio);
 		submit_bio_noacct(bio);
 		bio = split;
@@ -1410,6 +1415,13 @@ static void raid1_read_request(struct mddev *mddev, struct bio *bio,
 	read_bio->bi_private = r1_bio;
 	mddev_trace_remap(mddev, read_bio, r1_bio->sector);
 	submit_bio_noacct(read_bio);
+	return;
+
+err_handle:
+	atomic_dec(&mirror->rdev->nr_pending);
+	bio->bi_status = errno_to_blk_status(error);
+	set_bit(R1BIO_Uptodate, &r1_bio->state);
+	raid_end_bio_io(r1_bio);
 }
 
 static void raid1_write_request(struct mddev *mddev, struct bio *bio,
@@ -1417,7 +1429,7 @@ static void raid1_write_request(struct mddev *mddev, struct bio *bio,
 {
 	struct r1conf *conf = mddev->private;
 	struct r1bio *r1_bio;
-	int i, disks;
+	int i, disks, k, error;
 	unsigned long flags;
 	struct md_rdev *blocked_rdev;
 	int first_clone;
@@ -1576,6 +1588,11 @@ static void raid1_write_request(struct mddev *mddev, struct bio *bio,
 	if (max_sectors < bio_sectors(bio)) {
 		struct bio *split = bio_split(bio, max_sectors,
 					      GFP_NOIO, &conf->bio_split);
+
+		if (IS_ERR(split)) {
+			error = PTR_ERR(split);
+			goto err_handle;
+		}
 		bio_chain(split, bio);
 		submit_bio_noacct(bio);
 		bio = split;
@@ -1660,6 +1677,18 @@ static void raid1_write_request(struct mddev *mddev, struct bio *bio,
 
 	/* In case raid1d snuck in to freeze_array */
 	wake_up_barrier(conf);
+	return;
+err_handle:
+	for (k = 0; k < i; k++) {
+		if (r1_bio->bios[k]) {
+			rdev_dec_pending(conf->mirrors[k].rdev, mddev);
+			r1_bio->bios[k] = NULL;
+		}
+	}
+
+	bio->bi_status = errno_to_blk_status(error);
+	set_bit(R1BIO_Uptodate, &r1_bio->state);
+	raid_end_bio_io(r1_bio);
 }
 
 static bool raid1_make_request(struct mddev *mddev, struct bio *bio)
-- 
2.43.0

Re: [PATCH AUTOSEL 6.12 16/19] md/raid1: Handle bio_split() errors

[John Garry]

On 24/11/2024 12:38, Sasha Levin wrote:
> From: John Garry<john.g.garry@oracle.com>
> 
> [ Upstream commit b1a7ad8b5c4fa28325ee7b369a2d545d3e16ccde ]
> 
> Add proper bio_split() error handling. For any error, call
> raid_end_bio_io() and return.
> 
> For the case of an in the write path, we need to undo the increment in
> the rdev pending count and NULLify the r1_bio->bios[] pointers.
> 
> For read path failure, we need to undo rdev pending count increment from
> the earlier read_balance() call.
> 
> Reviewed-by: Yu Kuai<yukuai3@huawei.com>
> Reviewed-by: Hannes Reinecke<hare@suse.de>
> Signed-off-by: John Garry<john.g.garry@oracle.com>
> Link:https://urldefense.com/v3/__https://lore.kernel.org/ 
> r/20241111112150.3756529-6-john.g.garry@oracle.com__;!!ACWV5N9M2RV99hQ! 
> N4dieLgwxARnrFj9y51O80wHlzi_DtX0LRE- 
> kw6X6c0oWji1y3NBy1HIbHaHEkfRZJ57mxEq0kY_YRAnPg$ 
> Signed-off-by: Jens Axboe<axboe@kernel.dk>
> Signed-off-by: Sasha Levin<sashal@kernel.org>

I don't think that it is proper to backport this change without 
bio_split() error handling update. And I don't think that it is worth 
backporting the bio_split() error handling update.

Re: [PATCH AUTOSEL 6.12 16/19] md/raid1: Handle bio_split() errors

[Sasha Levin]

On Mon, Nov 25, 2024 at 08:55:19AM +0000, John Garry wrote:
>On 24/11/2024 12:38, Sasha Levin wrote:
>>From: John Garry<john.g.garry@oracle.com>
>>
>>[ Upstream commit b1a7ad8b5c4fa28325ee7b369a2d545d3e16ccde ]
>>
>>Add proper bio_split() error handling. For any error, call
>>raid_end_bio_io() and return.
>>
>>For the case of an in the write path, we need to undo the increment in
>>the rdev pending count and NULLify the r1_bio->bios[] pointers.
>>
>>For read path failure, we need to undo rdev pending count increment from
>>the earlier read_balance() call.
>>
>>Reviewed-by: Yu Kuai<yukuai3@huawei.com>
>>Reviewed-by: Hannes Reinecke<hare@suse.de>
>>Signed-off-by: John Garry<john.g.garry@oracle.com>
>>Link:https://urldefense.com/v3/__https://lore.kernel.org/ r/20241111112150.3756529-6-john.g.garry@oracle.com__;!!ACWV5N9M2RV99hQ! 
>>N4dieLgwxARnrFj9y51O80wHlzi_DtX0LRE- 
>>kw6X6c0oWji1y3NBy1HIbHaHEkfRZJ57mxEq0kY_YRAnPg$ Signed-off-by: Jens 
>>Axboe<axboe@kernel.dk>
>>Signed-off-by: Sasha Levin<sashal@kernel.org>
>
>I don't think that it is proper to backport this change without 
>bio_split() error handling update. And I don't think that it is worth 
>backporting the bio_split() error handling update.

I'll drop it, thanks!

-- 
Thanks,
Sasha