[PATCH 0/2] bcache: Fix block device claiming

[PATCH 0/2] bcache: Fix block device claiming

[Jan Kara]

Hello,

these two patches fix block device claiming for bcache broken by recent
Christoph's changes to blkdev_get_*() functions and also cleans up the layering
violation inside bcache which was the underlying cause of the breakage.

								Honza

[PATCH 1/2] bcache: Alloc holder object before async registration

[Jan Kara]

Allocate holder object (cache or cached_dev) before offloading the
rest of the startup to async work. This will allow us to open the block
block device with proper holder.

Signed-off-by: Jan Kara <jack@suse.cz>
---
 drivers/md/bcache/super.c | 66 +++++++++++++++------------------------
 1 file changed, 25 insertions(+), 41 deletions(-)

diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
index e2a803683105..913dd94353b6 100644
--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -2448,6 +2448,7 @@ struct async_reg_args {
 	struct cache_sb *sb;
 	struct cache_sb_disk *sb_disk;
 	struct block_device *bdev;
+	void *holder;
 };
 
 static void register_bdev_worker(struct work_struct *work)
@@ -2455,22 +2456,13 @@ static void register_bdev_worker(struct work_struct *work)
 	int fail = false;
 	struct async_reg_args *args =
 		container_of(work, struct async_reg_args, reg_work.work);
-	struct cached_dev *dc;
-
-	dc = kzalloc(sizeof(*dc), GFP_KERNEL);
-	if (!dc) {
-		fail = true;
-		put_page(virt_to_page(args->sb_disk));
-		blkdev_put(args->bdev, bcache_kobj);
-		goto out;
-	}
 
 	mutex_lock(&bch_register_lock);
-	if (register_bdev(args->sb, args->sb_disk, args->bdev, dc) < 0)
+	if (register_bdev(args->sb, args->sb_disk, args->bdev, args->holder)
+	    < 0)
 		fail = true;
 	mutex_unlock(&bch_register_lock);
 
-out:
 	if (fail)
 		pr_info("error %s: fail to register backing device\n",
 			args->path);
@@ -2485,21 +2477,11 @@ static void register_cache_worker(struct work_struct *work)
 	int fail = false;
 	struct async_reg_args *args =
 		container_of(work, struct async_reg_args, reg_work.work);
-	struct cache *ca;
-
-	ca = kzalloc(sizeof(*ca), GFP_KERNEL);
-	if (!ca) {
-		fail = true;
-		put_page(virt_to_page(args->sb_disk));
-		blkdev_put(args->bdev, bcache_kobj);
-		goto out;
-	}
 
 	/* blkdev_put() will be called in bch_cache_release() */
-	if (register_cache(args->sb, args->sb_disk, args->bdev, ca) != 0)
+	if (register_cache(args->sb, args->sb_disk, args->bdev, args->holder))
 		fail = true;
 
-out:
 	if (fail)
 		pr_info("error %s: fail to register cache device\n",
 			args->path);
@@ -2520,6 +2502,13 @@ static void register_device_async(struct async_reg_args *args)
 	queue_delayed_work(system_wq, &args->reg_work, 10);
 }
 
+static void *alloc_holder_object(struct cache_sb *sb)
+{
+	if (SB_IS_BDEV(sb))
+		return kzalloc(sizeof(struct cached_dev), GFP_KERNEL);
+	return kzalloc(sizeof(struct cache), GFP_KERNEL);
+}
+
 static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
 			       const char *buffer, size_t size)
 {
@@ -2528,6 +2517,7 @@ static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
 	struct cache_sb *sb;
 	struct cache_sb_disk *sb_disk;
 	struct block_device *bdev;
+	void *holder;
 	ssize_t ret;
 	bool async_registration = false;
 
@@ -2585,6 +2575,13 @@ static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
 	if (err)
 		goto out_blkdev_put;
 
+	holder = alloc_holder_object(sb);
+	if (!holder) {
+		ret = -ENOMEM;
+		err = "cannot allocate memory";
+		goto out_put_sb_page;
+	}
+
 	err = "failed to register device";
 
 	if (async_registration) {
@@ -2595,44 +2592,29 @@ static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
 		if (!args) {
 			ret = -ENOMEM;
 			err = "cannot allocate memory";
-			goto out_put_sb_page;
+			goto out_free_holder;
 		}
 
 		args->path	= path;
 		args->sb	= sb;
 		args->sb_disk	= sb_disk;
 		args->bdev	= bdev;
+		args->holder	= holder;
 		register_device_async(args);
 		/* No wait and returns to user space */
 		goto async_done;
 	}
 
 	if (SB_IS_BDEV(sb)) {
-		struct cached_dev *dc = kzalloc(sizeof(*dc), GFP_KERNEL);
-
-		if (!dc) {
-			ret = -ENOMEM;
-			err = "cannot allocate memory";
-			goto out_put_sb_page;
-		}
-
 		mutex_lock(&bch_register_lock);
-		ret = register_bdev(sb, sb_disk, bdev, dc);
+		ret = register_bdev(sb, sb_disk, bdev, holder);
 		mutex_unlock(&bch_register_lock);
 		/* blkdev_put() will be called in cached_dev_free() */
 		if (ret < 0)
 			goto out_free_sb;
 	} else {
-		struct cache *ca = kzalloc(sizeof(*ca), GFP_KERNEL);
-
-		if (!ca) {
-			ret = -ENOMEM;
-			err = "cannot allocate memory";
-			goto out_put_sb_page;
-		}
-
 		/* blkdev_put() will be called in bch_cache_release() */
-		ret = register_cache(sb, sb_disk, bdev, ca);
+		ret = register_cache(sb, sb_disk, bdev, holder);
 		if (ret)
 			goto out_free_sb;
 	}
@@ -2644,6 +2626,8 @@ static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
 async_done:
 	return size;
 
+out_free_holder:
+	kfree(holder);
 out_put_sb_page:
 	put_page(virt_to_page(sb_disk));
 out_blkdev_put:
-- 
2.35.3

Re: [PATCH 1/2] bcache: Alloc holder object before async registration

[Kent Overstreet]

On Wed, Jun 21, 2023 at 06:23:26PM +0200, Jan Kara wrote:
> Allocate holder object (cache or cached_dev) before offloading the
> rest of the startup to async work. This will allow us to open the block
> block device with proper holder.

This is a pretty big change for this fix, and we'd want to retest the
error paths - that's hard to do, because the fault injection framework I
was using for that never made it upstream.

What about just exposing a proper API for changing the holder? Wouldn't
that be simpler?




> 
> Signed-off-by: Jan Kara <jack@suse.cz>
> ---
>  drivers/md/bcache/super.c | 66 +++++++++++++++------------------------
>  1 file changed, 25 insertions(+), 41 deletions(-)
> 
> diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
> index e2a803683105..913dd94353b6 100644
> --- a/drivers/md/bcache/super.c
> +++ b/drivers/md/bcache/super.c
> @@ -2448,6 +2448,7 @@ struct async_reg_args {
>  	struct cache_sb *sb;
>  	struct cache_sb_disk *sb_disk;
>  	struct block_device *bdev;
> +	void *holder;
>  };
>  
>  static void register_bdev_worker(struct work_struct *work)
> @@ -2455,22 +2456,13 @@ static void register_bdev_worker(struct work_struct *work)
>  	int fail = false;
>  	struct async_reg_args *args =
>  		container_of(work, struct async_reg_args, reg_work.work);
> -	struct cached_dev *dc;
> -
> -	dc = kzalloc(sizeof(*dc), GFP_KERNEL);
> -	if (!dc) {
> -		fail = true;
> -		put_page(virt_to_page(args->sb_disk));
> -		blkdev_put(args->bdev, bcache_kobj);
> -		goto out;
> -	}
>  
>  	mutex_lock(&bch_register_lock);
> -	if (register_bdev(args->sb, args->sb_disk, args->bdev, dc) < 0)
> +	if (register_bdev(args->sb, args->sb_disk, args->bdev, args->holder)
> +	    < 0)
>  		fail = true;
>  	mutex_unlock(&bch_register_lock);
>  
> -out:
>  	if (fail)
>  		pr_info("error %s: fail to register backing device\n",
>  			args->path);
> @@ -2485,21 +2477,11 @@ static void register_cache_worker(struct work_struct *work)
>  	int fail = false;
>  	struct async_reg_args *args =
>  		container_of(work, struct async_reg_args, reg_work.work);
> -	struct cache *ca;
> -
> -	ca = kzalloc(sizeof(*ca), GFP_KERNEL);
> -	if (!ca) {
> -		fail = true;
> -		put_page(virt_to_page(args->sb_disk));
> -		blkdev_put(args->bdev, bcache_kobj);
> -		goto out;
> -	}
>  
>  	/* blkdev_put() will be called in bch_cache_release() */
> -	if (register_cache(args->sb, args->sb_disk, args->bdev, ca) != 0)
> +	if (register_cache(args->sb, args->sb_disk, args->bdev, args->holder))
>  		fail = true;
>  
> -out:
>  	if (fail)
>  		pr_info("error %s: fail to register cache device\n",
>  			args->path);
> @@ -2520,6 +2502,13 @@ static void register_device_async(struct async_reg_args *args)
>  	queue_delayed_work(system_wq, &args->reg_work, 10);
>  }
>  
> +static void *alloc_holder_object(struct cache_sb *sb)
> +{
> +	if (SB_IS_BDEV(sb))
> +		return kzalloc(sizeof(struct cached_dev), GFP_KERNEL);
> +	return kzalloc(sizeof(struct cache), GFP_KERNEL);
> +}
> +
>  static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
>  			       const char *buffer, size_t size)
>  {
> @@ -2528,6 +2517,7 @@ static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
>  	struct cache_sb *sb;
>  	struct cache_sb_disk *sb_disk;
>  	struct block_device *bdev;
> +	void *holder;
>  	ssize_t ret;
>  	bool async_registration = false;
>  
> @@ -2585,6 +2575,13 @@ static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
>  	if (err)
>  		goto out_blkdev_put;
>  
> +	holder = alloc_holder_object(sb);
> +	if (!holder) {
> +		ret = -ENOMEM;
> +		err = "cannot allocate memory";
> +		goto out_put_sb_page;
> +	}
> +
>  	err = "failed to register device";
>  
>  	if (async_registration) {
> @@ -2595,44 +2592,29 @@ static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
>  		if (!args) {
>  			ret = -ENOMEM;
>  			err = "cannot allocate memory";
> -			goto out_put_sb_page;
> +			goto out_free_holder;
>  		}
>  
>  		args->path	= path;
>  		args->sb	= sb;
>  		args->sb_disk	= sb_disk;
>  		args->bdev	= bdev;
> +		args->holder	= holder;
>  		register_device_async(args);
>  		/* No wait and returns to user space */
>  		goto async_done;
>  	}
>  
>  	if (SB_IS_BDEV(sb)) {
> -		struct cached_dev *dc = kzalloc(sizeof(*dc), GFP_KERNEL);
> -
> -		if (!dc) {
> -			ret = -ENOMEM;
> -			err = "cannot allocate memory";
> -			goto out_put_sb_page;
> -		}
> -
>  		mutex_lock(&bch_register_lock);
> -		ret = register_bdev(sb, sb_disk, bdev, dc);
> +		ret = register_bdev(sb, sb_disk, bdev, holder);
>  		mutex_unlock(&bch_register_lock);
>  		/* blkdev_put() will be called in cached_dev_free() */
>  		if (ret < 0)
>  			goto out_free_sb;
>  	} else {
> -		struct cache *ca = kzalloc(sizeof(*ca), GFP_KERNEL);
> -
> -		if (!ca) {
> -			ret = -ENOMEM;
> -			err = "cannot allocate memory";
> -			goto out_put_sb_page;
> -		}
> -
>  		/* blkdev_put() will be called in bch_cache_release() */
> -		ret = register_cache(sb, sb_disk, bdev, ca);
> +		ret = register_cache(sb, sb_disk, bdev, holder);
>  		if (ret)
>  			goto out_free_sb;
>  	}
> @@ -2644,6 +2626,8 @@ static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
>  async_done:
>  	return size;
>  
> +out_free_holder:
> +	kfree(holder);
>  out_put_sb_page:
>  	put_page(virt_to_page(sb_disk));
>  out_blkdev_put:
> -- 
> 2.35.3
> 

Re: [PATCH 1/2] bcache: Alloc holder object before async registration

[Jan Kara]

On Wed 21-06-23 13:56:59, Kent Overstreet wrote:
> On Wed, Jun 21, 2023 at 06:23:26PM +0200, Jan Kara wrote:
> > Allocate holder object (cache or cached_dev) before offloading the
> > rest of the startup to async work. This will allow us to open the block
> > block device with proper holder.
> 
> This is a pretty big change for this fix, and we'd want to retest the
> error paths - that's hard to do, because the fault injection framework I
> was using for that never made it upstream.

I agree those are somewhat difficult to test. Although with memory
allocation error injection, we can easily simulate failures in
alloc_holder_object() or say later in bcache_device_init() if that's what
you're after to give at least some testing to the error paths. Admittedly,
I've just tested that registering and unregistering bcache devices works
without giving warnings. Or are you more worried about the "reopen the
block device" logic (and error handling) in the second patch?

> What about just exposing a proper API for changing the holder? Wouldn't
> that be simpler?

It would be doable but frankly I'd prefer to avoid implementing the API for
changing the holder just for bcache. For all I care bcache can also just
generate random cookie (or an id from IDA) and pass it as a holder to
blkdev_get_by_dev(). It would do the job as well and we then don't have to
play games with changing the holder. It would just need to be propagated to
the places doing blkdev_put(). Do you find that better?

I'm now working on a changes that will make blkdev_get_by_dev() return
bdev_handle (which contains bdev pointer but also other stuff we need to
propagate to blkdev_put()) so when that is done, the cookie propagation
will happen automatically.

								Honza
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR

Re: [PATCH 1/2] bcache: Alloc holder object before async registration

[Kent Overstreet]

On Thu, Jun 22, 2023 at 12:09:54PM +0200, Jan Kara wrote:
> On Wed 21-06-23 13:56:59, Kent Overstreet wrote:
> > On Wed, Jun 21, 2023 at 06:23:26PM +0200, Jan Kara wrote:
> > > Allocate holder object (cache or cached_dev) before offloading the
> > > rest of the startup to async work. This will allow us to open the block
> > > block device with proper holder.
> > 
> > This is a pretty big change for this fix, and we'd want to retest the
> > error paths - that's hard to do, because the fault injection framework I
> > was using for that never made it upstream.
> 
> I agree those are somewhat difficult to test. Although with memory
> allocation error injection, we can easily simulate failures in
> alloc_holder_object() or say later in bcache_device_init() if that's what
> you're after to give at least some testing to the error paths. Admittedly,
> I've just tested that registering and unregistering bcache devices works
> without giving warnings. Or are you more worried about the "reopen the
> block device" logic (and error handling) in the second patch?

All error paths need to be tested, yeah.

> > What about just exposing a proper API for changing the holder? Wouldn't
> > that be simpler?
> 
> It would be doable but frankly I'd prefer to avoid implementing the API for
> changing the holder just for bcache. For all I care bcache can also just
> generate random cookie (or an id from IDA) and pass it as a holder to
> blkdev_get_by_dev(). It would do the job as well and we then don't have to
> play games with changing the holder. It would just need to be propagated to
> the places doing blkdev_put(). Do you find that better?

Well, looking over the code it doesn't seem like it would really
simplify the fix, unfortunately.

bcachefs has the same issue, but in bcachefs we've already got a handle
object where we can allocate and stash a holder - analagous to the
bdev_handle you're working on.

> I'm now working on a changes that will make blkdev_get_by_dev() return
> bdev_handle (which contains bdev pointer but also other stuff we need to
> propagate to blkdev_put()) so when that is done, the cookie propagation
> will happen automatically.

bdev_handle definitely sounds like the right direction.

Just changing the holder really seems like it should be easiest to me,
and it can get deleted after bdev_handle lands, but maybe there's a new
wrinkle I'm not aware of?

Anyways, as the error paths get tested I'm ok with this patchset - it's
fine if it's done completely by hand (you can just add a goto fail in
the appropriate place and make sure nothing explodes).

Coli - we should talk about testing at some point. I've been working on
test infrastructure; it would be great to get the bcache tests in ktest
updated, I've now got a CI we could point at those tests.

Christoph - you really gotta start CCing people properly, the patch that
broke this didn't even it linux-bcache. No bueno.

Re: [PATCH 1/2] bcache: Alloc holder object before async registration

[Christoph Hellwig]

On Thu, Jun 22, 2023 at 08:05:48AM -0400, Kent Overstreet wrote:
> Christoph - you really gotta start CCing people properly, the patch that
> broke this didn't even it linux-bcache. No bueno.

The series did absolutely go out to linux-bcache.  See here for v2:

https://lore.kernel.org/linux-bcache/20230608110258.189493-13-hch@lst.de/T/#u

[PATCH 2/2] bcache: Fix bcache device claiming

[Jan Kara]

Commit 2736e8eeb0cc ("block: use the holder as indication for exclusive
opens") introduced a change that blkdev_put() has to get exclusive
holder of the bdev as an argument. However it overlooked that
register_bdev() and register_cache() overwrite the bdev->bd_holder field
in the block device to point to the real owning object which was not
available at the time we called blkdev_get_by_path(). Messing with bdev
internals like this is a layering violation and it also causes
blkdev_put() to issue warning about mismatching holders.

Fix bcache to reopen the block device with appropriate holder once it is
available which also restores the behavior that multiple bcache caches
cannot claim the same device which was also broken by commit
2736e8eeb0cc.

Fixes: 2736e8eeb0cc ("block: use the holder as indication for exclusive opens")
Signed-off-by: Jan Kara <jack@suse.cz>
---
 drivers/md/bcache/super.c | 63 ++++++++++++++++++++++-----------------
 1 file changed, 36 insertions(+), 27 deletions(-)

diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
index 913dd94353b6..9738e8c0cbfc 100644
--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -1369,7 +1369,7 @@ static void cached_dev_free(struct closure *cl)
 		put_page(virt_to_page(dc->sb_disk));
 
 	if (!IS_ERR_OR_NULL(dc->bdev))
-		blkdev_put(dc->bdev, bcache_kobj);
+		blkdev_put(dc->bdev, dc);
 
 	wake_up(&unregister_wait);
 
@@ -1453,7 +1453,6 @@ static int register_bdev(struct cache_sb *sb, struct cache_sb_disk *sb_disk,
 
 	memcpy(&dc->sb, sb, sizeof(struct cache_sb));
 	dc->bdev = bdev;
-	dc->bdev->bd_holder = dc;
 	dc->sb_disk = sb_disk;
 
 	if (cached_dev_init(dc, sb->block_size << 9))
@@ -2218,7 +2217,7 @@ void bch_cache_release(struct kobject *kobj)
 		put_page(virt_to_page(ca->sb_disk));
 
 	if (!IS_ERR_OR_NULL(ca->bdev))
-		blkdev_put(ca->bdev, bcache_kobj);
+		blkdev_put(ca->bdev, ca);
 
 	kfree(ca);
 	module_put(THIS_MODULE);
@@ -2345,7 +2344,6 @@ static int register_cache(struct cache_sb *sb, struct cache_sb_disk *sb_disk,
 
 	memcpy(&ca->sb, sb, sizeof(struct cache_sb));
 	ca->bdev = bdev;
-	ca->bdev->bd_holder = ca;
 	ca->sb_disk = sb_disk;
 
 	if (bdev_max_discard_sectors((bdev)))
@@ -2359,7 +2357,7 @@ static int register_cache(struct cache_sb *sb, struct cache_sb_disk *sb_disk,
 		 * call blkdev_put() to bdev in bch_cache_release(). So we
 		 * explicitly call blkdev_put() here.
 		 */
-		blkdev_put(bdev, bcache_kobj);
+		blkdev_put(bdev, ca);
 		if (ret == -ENOMEM)
 			err = "cache_alloc(): -ENOMEM";
 		else if (ret == -EPERM)
@@ -2516,10 +2514,11 @@ static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
 	char *path = NULL;
 	struct cache_sb *sb;
 	struct cache_sb_disk *sb_disk;
-	struct block_device *bdev;
-	void *holder;
+	struct block_device *bdev, *bdev2;
+	void *holder = NULL;
 	ssize_t ret;
 	bool async_registration = false;
+	bool quiet = false;
 
 #ifdef CONFIG_BCACHE_ASYNC_REGISTRATION
 	async_registration = true;
@@ -2548,24 +2547,9 @@ static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
 
 	ret = -EINVAL;
 	err = "failed to open device";
-	bdev = blkdev_get_by_path(strim(path), BLK_OPEN_READ | BLK_OPEN_WRITE,
-				  bcache_kobj, NULL);
-	if (IS_ERR(bdev)) {
-		if (bdev == ERR_PTR(-EBUSY)) {
-			dev_t dev;
-
-			mutex_lock(&bch_register_lock);
-			if (lookup_bdev(strim(path), &dev) == 0 &&
-			    bch_is_open(dev))
-				err = "device already registered";
-			else
-				err = "device busy";
-			mutex_unlock(&bch_register_lock);
-			if (attr == &ksysfs_register_quiet)
-				goto done;
-		}
+	bdev = blkdev_get_by_path(strim(path), BLK_OPEN_READ, NULL, NULL);
+	if (IS_ERR(bdev))
 		goto out_free_sb;
-	}
 
 	err = "failed to set blocksize";
 	if (set_blocksize(bdev, 4096))
@@ -2582,6 +2566,31 @@ static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
 		goto out_put_sb_page;
 	}
 
+	/* Now reopen in exclusive mode with proper holder */
+	bdev2 = blkdev_get_by_dev(bdev->bd_dev, BLK_OPEN_READ | BLK_OPEN_WRITE,
+				  holder, NULL);
+	blkdev_put(bdev, NULL);
+	bdev = bdev2;
+	if (IS_ERR(bdev))
+		ret = PTR_ERR(bdev);
+		if (bdev == ERR_PTR(-EBUSY)) {
+			dev_t dev;
+
+			mutex_lock(&bch_register_lock);
+			if (lookup_bdev(strim(path), &dev) == 0 &&
+			    bch_is_open(dev))
+				err = "device already registered";
+			else
+				err = "device busy";
+			mutex_unlock(&bch_register_lock);
+			if (attr == &ksysfs_register_quiet) {
+				quiet = true;
+				ret = size;
+			}
+		}
+		goto out_free_holder;
+	}
+
 	err = "failed to register device";
 
 	if (async_registration) {
@@ -2619,7 +2628,6 @@ static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
 			goto out_free_sb;
 	}
 
-done:
 	kfree(sb);
 	kfree(path);
 	module_put(THIS_MODULE);
@@ -2631,7 +2639,7 @@ static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
 out_put_sb_page:
 	put_page(virt_to_page(sb_disk));
 out_blkdev_put:
-	blkdev_put(bdev, register_bcache);
+	blkdev_put(bdev, holder);
 out_free_sb:
 	kfree(sb);
 out_free_path:
@@ -2640,7 +2648,8 @@ static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
 out_module_put:
 	module_put(THIS_MODULE);
 out:
-	pr_info("error %s: %s\n", path?path:"", err);
+	if (!quiet)
+		pr_info("error %s: %s\n", path?path:"", err);
 	return ret;
 }
 
-- 
2.35.3

Re: [PATCH 2/2] bcache: Fix bcache device claiming

[kernel test robot]

Hi Jan,

kernel test robot noticed the following build errors:

[auto build test ERROR on axboe-block/for-6.5/block]
[also build test ERROR on next-20230621]
[cannot apply to linus/master v6.4-rc7]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Jan-Kara/bcache-Alloc-holder-object-before-async-registration/20230622-002543
base:   https://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git for-6.5/block
patch link:    https://lore.kernel.org/r/20230621162333.30027-2-jack%40suse.cz
patch subject: [PATCH 2/2] bcache: Fix bcache device claiming
config: s390-defconfig (https://download.01.org/0day-ci/archive/20230622/202306220927.dRUNZbek-lkp@intel.com/config)
compiler: s390-linux-gcc (GCC) 12.3.0
reproduce: (https://download.01.org/0day-ci/archive/20230622/202306220927.dRUNZbek-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202306220927.dRUNZbek-lkp@intel.com/

All error/warnings (new ones prefixed by >>):

   drivers/md/bcache/super.c: In function 'register_bcache':
>> drivers/md/bcache/super.c:2574:9: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
    2574 |         if (IS_ERR(bdev))
         |         ^~
   drivers/md/bcache/super.c:2576:17: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'
    2576 |                 if (bdev == ERR_PTR(-EBUSY)) {
         |                 ^~
>> drivers/md/bcache/super.c:2591:17: error: label 'out_free_holder' used but not defined
    2591 |                 goto out_free_holder;
         |                 ^~~~
>> drivers/md/bcache/super.c:2566:17: error: label 'out_put_sb_page' used but not defined
    2566 |                 goto out_put_sb_page;
         |                 ^~~~
>> drivers/md/bcache/super.c:2560:17: error: label 'out_blkdev_put' used but not defined
    2560 |                 goto out_blkdev_put;
         |                 ^~~~
>> drivers/md/bcache/super.c:2552:17: error: label 'out_free_sb' used but not defined
    2552 |                 goto out_free_sb;
         |                 ^~~~
>> drivers/md/bcache/super.c:2546:17: error: label 'out_free_path' used but not defined
    2546 |                 goto out_free_path;
         |                 ^~~~
>> drivers/md/bcache/super.c:2542:17: error: label 'out_module_put' used but not defined
    2542 |                 goto out_module_put;
         |                 ^~~~
>> drivers/md/bcache/super.c:2530:17: error: label 'out' used but not defined
    2530 |                 goto out;
         |                 ^~~~
>> drivers/md/bcache/super.c:2521:14: warning: variable 'quiet' set but not used [-Wunused-but-set-variable]
    2521 |         bool quiet = false;
         |              ^~~~~
   drivers/md/bcache/super.c:2520:14: warning: unused variable 'async_registration' [-Wunused-variable]
    2520 |         bool async_registration = false;
         |              ^~~~~~~~~~~~~~~~~~
>> drivers/md/bcache/super.c:2519:17: warning: variable 'ret' set but not used [-Wunused-but-set-variable]
    2519 |         ssize_t ret;
         |                 ^~~
   drivers/md/bcache/super.c:2592:9: error: no return statement in function returning non-void [-Werror=return-type]
    2592 |         }
         |         ^
   drivers/md/bcache/super.c: At top level:
>> drivers/md/bcache/super.c:2594:9: warning: data definition has no type or storage class
    2594 |         err = "failed to register device";
         |         ^~~
>> drivers/md/bcache/super.c:2594:9: error: type defaults to 'int' in declaration of 'err' [-Werror=implicit-int]
>> drivers/md/bcache/super.c:2594:15: warning: initialization of 'int' from 'char *' makes integer from pointer without a cast [-Wint-conversion]
    2594 |         err = "failed to register device";
         |               ^~~~~~~~~~~~~~~~~~~~~~~~~~~
>> drivers/md/bcache/super.c:2594:15: error: initializer element is not computable at load time
>> drivers/md/bcache/super.c:2596:9: error: expected identifier or '(' before 'if'
    2596 |         if (async_registration) {
         |         ^~
   drivers/md/bcache/super.c:2617:9: error: expected identifier or '(' before 'if'
    2617 |         if (SB_IS_BDEV(sb)) {
         |         ^~
>> drivers/md/bcache/super.c:2624:11: error: expected identifier or '(' before 'else'
    2624 |         } else {
         |           ^~~~
   drivers/md/bcache/super.c:2631:9: warning: data definition has no type or storage class
    2631 |         kfree(sb);
         |         ^~~~~
>> drivers/md/bcache/super.c:2631:9: error: type defaults to 'int' in declaration of 'kfree' [-Werror=implicit-int]
>> drivers/md/bcache/super.c:2631:9: warning: parameter names (without types) in function declaration
>> drivers/md/bcache/super.c:2631:9: error: conflicting types for 'kfree'; have 'int()'
   In file included from include/linux/fs.h:45,
                    from include/linux/highmem.h:5,
                    from include/linux/bvec.h:10,
                    from include/linux/blk_types.h:10,
                    from include/linux/bio.h:10,
                    from drivers/md/bcache/bcache.h:181,
                    from drivers/md/bcache/super.c:10:
   include/linux/slab.h:210:6: note: previous declaration of 'kfree' with type 'void(const void *)'
     210 | void kfree(const void *objp);
         |      ^~~~~
   drivers/md/bcache/super.c:2632:9: warning: data definition has no type or storage class
    2632 |         kfree(path);
         |         ^~~~~
   drivers/md/bcache/super.c:2632:9: error: type defaults to 'int' in declaration of 'kfree' [-Werror=implicit-int]
   drivers/md/bcache/super.c:2632:9: warning: parameter names (without types) in function declaration
   drivers/md/bcache/super.c:2632:9: error: conflicting types for 'kfree'; have 'int()'
   include/linux/slab.h:210:6: note: previous declaration of 'kfree' with type 'void(const void *)'
     210 | void kfree(const void *objp);
         |      ^~~~~
   In file included from include/linux/linkage.h:7,
                    from include/linux/preempt.h:10,
                    from include/linux/spinlock.h:56,
                    from include/linux/wait.h:9,
                    from include/linux/mempool.h:8,
                    from include/linux/bio.h:8:
>> include/linux/export.h:27:21: error: expected declaration specifiers or '...' before '(' token
      27 | #define THIS_MODULE (&__this_module)
         |                     ^
   drivers/md/bcache/super.c:2633:20: note: in expansion of macro 'THIS_MODULE'
    2633 |         module_put(THIS_MODULE);
         |                    ^~~~~~~~~~~
   drivers/md/bcache/super.c:2634:11: error: expected '=', ',', ';', 'asm' or '__attribute__' before ':' token
    2634 | async_done:
         |           ^
   drivers/md/bcache/super.c:2637:16: error: expected '=', ',', ';', 'asm' or '__attribute__' before ':' token
    2637 | out_free_holder:
         |                ^
   drivers/md/bcache/super.c:2639:16: error: expected '=', ',', ';', 'asm' or '__attribute__' before ':' token
    2639 | out_put_sb_page:
         |                ^
   drivers/md/bcache/super.c:2641:15: error: expected '=', ',', ';', 'asm' or '__attribute__' before ':' token
    2641 | out_blkdev_put:
         |               ^
   drivers/md/bcache/super.c:2643:12: error: expected '=', ',', ';', 'asm' or '__attribute__' before ':' token
    2643 | out_free_sb:
         |            ^
   drivers/md/bcache/super.c:2645:14: error: expected '=', ',', ';', 'asm' or '__attribute__' before ':' token
    2645 | out_free_path:
         |              ^
   drivers/md/bcache/super.c:2647:9: warning: data definition has no type or storage class
    2647 |         path = NULL;
         |         ^~~~
   drivers/md/bcache/super.c:2647:9: error: type defaults to 'int' in declaration of 'path' [-Werror=implicit-int]
   In file included from include/uapi/linux/posix_types.h:5,
                    from include/uapi/linux/types.h:14,
                    from include/linux/types.h:6,
                    from include/linux/kasan-checks.h:5,
                    from include/asm-generic/rwonce.h:26,
                    from arch/s390/include/asm/rwonce.h:29,
                    from include/linux/compiler.h:247,
                    from include/linux/build_bug.h:5,
                    from include/linux/container_of.h:5,
                    from include/linux/list.h:5,
                    from include/linux/wait.h:7:
   include/linux/stddef.h:8:14: warning: initialization of 'int' from 'void *' makes integer from pointer without a cast [-Wint-conversion]
       8 | #define NULL ((void *)0)
         |              ^
   drivers/md/bcache/super.c:2647:16: note: in expansion of macro 'NULL'
    2647 |         path = NULL;
         |                ^~~~
   drivers/md/bcache/super.c:2648:15: error: expected '=', ',', ';', 'asm' or '__attribute__' before ':' token
    2648 | out_module_put:
         |               ^
   drivers/md/bcache/super.c:2650:4: error: expected '=', ',', ';', 'asm' or '__attribute__' before ':' token
    2650 | out:
         |    ^
   In file included from include/asm-generic/bug.h:22,
                    from arch/s390/include/asm/bug.h:69,
                    from include/linux/bug.h:5,
                    from include/linux/thread_info.h:13,
                    from arch/s390/include/asm/preempt.h:6,
                    from include/linux/preempt.h:78:
   include/linux/printk.h:428:10: error: expected identifier or '(' before ')' token
     428 |         })
         |          ^
   include/linux/printk.h:455:26: note: in expansion of macro 'printk_index_wrap'
     455 | #define printk(fmt, ...) printk_index_wrap(_printk, fmt, ##__VA_ARGS__)
         |                          ^~~~~~~~~~~~~~~~~
   include/linux/printk.h:528:9: note: in expansion of macro 'printk'
     528 |         printk(KERN_INFO pr_fmt(fmt), ##__VA_ARGS__)
         |         ^~~~~~
   drivers/md/bcache/super.c:2652:17: note: in expansion of macro 'pr_info'
    2652 |                 pr_info("error %s: %s\n", path?path:"", err);
         |                 ^~~~~~~
   drivers/md/bcache/super.c:2653:9: error: expected identifier or '(' before 'return'
    2653 |         return ret;
         |         ^~~~~~
   drivers/md/bcache/super.c:2654:1: error: expected identifier or '(' before '}' token
    2654 | }
         | ^
   drivers/md/bcache/super.c:2492:13: warning: 'register_device_async' defined but not used [-Wunused-function]
    2492 | static void register_device_async(struct async_reg_args *args)
         |             ^~~~~~~~~~~~~~~~~~~~~
   cc1: some warnings being treated as errors


vim +/out_free_holder +2591 drivers/md/bcache/super.c

  2509	
  2510	static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
  2511				       const char *buffer, size_t size)
  2512	{
  2513		const char *err;
  2514		char *path = NULL;
  2515		struct cache_sb *sb;
  2516		struct cache_sb_disk *sb_disk;
  2517		struct block_device *bdev, *bdev2;
  2518		void *holder = NULL;
> 2519		ssize_t ret;
  2520		bool async_registration = false;
> 2521		bool quiet = false;
  2522	
  2523	#ifdef CONFIG_BCACHE_ASYNC_REGISTRATION
  2524		async_registration = true;
  2525	#endif
  2526	
  2527		ret = -EBUSY;
  2528		err = "failed to reference bcache module";
  2529		if (!try_module_get(THIS_MODULE))
> 2530			goto out;
  2531	
  2532		/* For latest state of bcache_is_reboot */
  2533		smp_mb();
  2534		err = "bcache is in reboot";
  2535		if (bcache_is_reboot)
  2536			goto out_module_put;
  2537	
  2538		ret = -ENOMEM;
  2539		err = "cannot allocate memory";
  2540		path = kstrndup(buffer, size, GFP_KERNEL);
  2541		if (!path)
> 2542			goto out_module_put;
  2543	
  2544		sb = kmalloc(sizeof(struct cache_sb), GFP_KERNEL);
  2545		if (!sb)
> 2546			goto out_free_path;
  2547	
  2548		ret = -EINVAL;
  2549		err = "failed to open device";
  2550		bdev = blkdev_get_by_path(strim(path), BLK_OPEN_READ, NULL, NULL);
  2551		if (IS_ERR(bdev))
> 2552			goto out_free_sb;
  2553	
  2554		err = "failed to set blocksize";
  2555		if (set_blocksize(bdev, 4096))
  2556			goto out_blkdev_put;
  2557	
  2558		err = read_super(sb, bdev, &sb_disk);
  2559		if (err)
> 2560			goto out_blkdev_put;
  2561	
  2562		holder = alloc_holder_object(sb);
  2563		if (!holder) {
  2564			ret = -ENOMEM;
  2565			err = "cannot allocate memory";
> 2566			goto out_put_sb_page;
  2567		}
  2568	
  2569		/* Now reopen in exclusive mode with proper holder */
  2570		bdev2 = blkdev_get_by_dev(bdev->bd_dev, BLK_OPEN_READ | BLK_OPEN_WRITE,
  2571					  holder, NULL);
  2572		blkdev_put(bdev, NULL);
  2573		bdev = bdev2;
> 2574		if (IS_ERR(bdev))
  2575			ret = PTR_ERR(bdev);
> 2576			if (bdev == ERR_PTR(-EBUSY)) {
  2577				dev_t dev;
  2578	
  2579				mutex_lock(&bch_register_lock);
  2580				if (lookup_bdev(strim(path), &dev) == 0 &&
  2581				    bch_is_open(dev))
  2582					err = "device already registered";
  2583				else
  2584					err = "device busy";
  2585				mutex_unlock(&bch_register_lock);
  2586				if (attr == &ksysfs_register_quiet) {
  2587					quiet = true;
  2588					ret = size;
  2589				}
  2590			}
> 2591			goto out_free_holder;
> 2592		}
  2593	
> 2594		err = "failed to register device";
  2595	
> 2596		if (async_registration) {
  2597			/* register in asynchronous way */
  2598			struct async_reg_args *args =
  2599				kzalloc(sizeof(struct async_reg_args), GFP_KERNEL);
  2600	
  2601			if (!args) {
  2602				ret = -ENOMEM;
  2603				err = "cannot allocate memory";
  2604				goto out_free_holder;
  2605			}
  2606	
  2607			args->path	= path;
  2608			args->sb	= sb;
  2609			args->sb_disk	= sb_disk;
  2610			args->bdev	= bdev;
  2611			args->holder	= holder;
  2612			register_device_async(args);
  2613			/* No wait and returns to user space */
  2614			goto async_done;
  2615		}
  2616	
> 2617		if (SB_IS_BDEV(sb)) {
  2618			mutex_lock(&bch_register_lock);
  2619			ret = register_bdev(sb, sb_disk, bdev, holder);
  2620			mutex_unlock(&bch_register_lock);
  2621			/* blkdev_put() will be called in cached_dev_free() */
  2622			if (ret < 0)
  2623				goto out_free_sb;
> 2624		} else {
  2625			/* blkdev_put() will be called in bch_cache_release() */
  2626			ret = register_cache(sb, sb_disk, bdev, holder);
  2627			if (ret)
  2628				goto out_free_sb;
  2629		}
  2630	
> 2631		kfree(sb);
  2632		kfree(path);
> 2633		module_put(THIS_MODULE);
> 2634	async_done:
  2635		return size;
  2636	
  2637	out_free_holder:
  2638		kfree(holder);
  2639	out_put_sb_page:
  2640		put_page(virt_to_page(sb_disk));
  2641	out_blkdev_put:
  2642		blkdev_put(bdev, holder);
> 2643	out_free_sb:
  2644		kfree(sb);
  2645	out_free_path:
  2646		kfree(path);
> 2647		path = NULL;
  2648	out_module_put:
  2649		module_put(THIS_MODULE);
  2650	out:
  2651		if (!quiet)
> 2652			pr_info("error %s: %s\n", path?path:"", err);
> 2653		return ret;
> 2654	}
  2655	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Re: [PATCH 2/2] bcache: Fix bcache device claiming

[Jan Kara]

Hi,

On Thu 22-06-23 09:23:21, kernel test robot wrote:
> Hi Jan,
> 
> kernel test robot noticed the following build errors:
> 
> [auto build test ERROR on axboe-block/for-6.5/block]
> [also build test ERROR on next-20230621]
> [cannot apply to linus/master v6.4-rc7]
> [If your patch is applied to the wrong git tree, kindly drop us a note.
> And when submitting patch, we suggest to use '--base' as documented in
> https://git-scm.com/docs/git-format-patch#_base_tree_information]

Yeah, there's missing '{' there. The two fixes were part of a larger series
and I've mistakenly fixed this up only in the next patch in the series.
I'll resend once we agree with Kent how to proceed.

								Honza
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR

Re: [PATCH 2/2] bcache: Fix bcache device claiming

[kernel test robot]

Hi Jan,

kernel test robot noticed the following build warnings:

[auto build test WARNING on axboe-block/for-6.5/block]
[also build test WARNING on next-20230621]
[cannot apply to linus/master hch-configfs/for-next v6.4-rc7]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Jan-Kara/bcache-Alloc-holder-object-before-async-registration/20230622-002543
base:   https://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git for-6.5/block
patch link:    https://lore.kernel.org/r/20230621162333.30027-2-jack%40suse.cz
patch subject: [PATCH 2/2] bcache: Fix bcache device claiming
config: s390-allmodconfig (https://download.01.org/0day-ci/archive/20230622/202306220914.B0THiZdL-lkp@intel.com/config)
compiler: s390-linux-gcc (GCC) 12.3.0
reproduce: (https://download.01.org/0day-ci/archive/20230622/202306220914.B0THiZdL-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202306220914.B0THiZdL-lkp@intel.com/

All warnings (new ones prefixed by >>):

   drivers/md/bcache/super.c: In function 'register_bcache':
   drivers/md/bcache/super.c:2574:9: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
    2574 |         if (IS_ERR(bdev))
         |         ^~
   drivers/md/bcache/super.c:2576:17: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'
    2576 |                 if (bdev == ERR_PTR(-EBUSY)) {
         |                 ^~
   drivers/md/bcache/super.c:2591:17: error: label 'out_free_holder' used but not defined
    2591 |                 goto out_free_holder;
         |                 ^~~~
   drivers/md/bcache/super.c:2566:17: error: label 'out_put_sb_page' used but not defined
    2566 |                 goto out_put_sb_page;
         |                 ^~~~
   drivers/md/bcache/super.c:2560:17: error: label 'out_blkdev_put' used but not defined
    2560 |                 goto out_blkdev_put;
         |                 ^~~~
   drivers/md/bcache/super.c:2552:17: error: label 'out_free_sb' used but not defined
    2552 |                 goto out_free_sb;
         |                 ^~~~
   drivers/md/bcache/super.c:2546:17: error: label 'out_free_path' used but not defined
    2546 |                 goto out_free_path;
         |                 ^~~~
   drivers/md/bcache/super.c:2542:17: error: label 'out_module_put' used but not defined
    2542 |                 goto out_module_put;
         |                 ^~~~
   drivers/md/bcache/super.c:2530:17: error: label 'out' used but not defined
    2530 |                 goto out;
         |                 ^~~~
   drivers/md/bcache/super.c:2521:14: warning: variable 'quiet' set but not used [-Wunused-but-set-variable]
    2521 |         bool quiet = false;
         |              ^~~~~
>> drivers/md/bcache/super.c:2520:14: warning: variable 'async_registration' set but not used [-Wunused-but-set-variable]
    2520 |         bool async_registration = false;
         |              ^~~~~~~~~~~~~~~~~~
   drivers/md/bcache/super.c:2519:17: warning: variable 'ret' set but not used [-Wunused-but-set-variable]
    2519 |         ssize_t ret;
         |                 ^~~
   drivers/md/bcache/super.c:2592:9: error: no return statement in function returning non-void [-Werror=return-type]
    2592 |         }
         |         ^
   drivers/md/bcache/super.c: At top level:
   drivers/md/bcache/super.c:2594:9: warning: data definition has no type or storage class
    2594 |         err = "failed to register device";
         |         ^~~
   drivers/md/bcache/super.c:2594:9: error: type defaults to 'int' in declaration of 'err' [-Werror=implicit-int]
   drivers/md/bcache/super.c:2594:15: warning: initialization of 'int' from 'char *' makes integer from pointer without a cast [-Wint-conversion]
    2594 |         err = "failed to register device";
         |               ^~~~~~~~~~~~~~~~~~~~~~~~~~~
   drivers/md/bcache/super.c:2594:15: error: initializer element is not computable at load time
   drivers/md/bcache/super.c:2596:9: error: expected identifier or '(' before 'if'
    2596 |         if (async_registration) {
         |         ^~
   drivers/md/bcache/super.c:2617:9: error: expected identifier or '(' before 'if'
    2617 |         if (SB_IS_BDEV(sb)) {
         |         ^~
   drivers/md/bcache/super.c:2624:11: error: expected identifier or '(' before 'else'
    2624 |         } else {
         |           ^~~~
   drivers/md/bcache/super.c:2631:9: warning: data definition has no type or storage class
    2631 |         kfree(sb);
         |         ^~~~~
   drivers/md/bcache/super.c:2631:9: error: type defaults to 'int' in declaration of 'kfree' [-Werror=implicit-int]
   drivers/md/bcache/super.c:2631:9: warning: parameter names (without types) in function declaration
   drivers/md/bcache/super.c:2631:9: error: conflicting types for 'kfree'; have 'int()'
   In file included from include/linux/fs.h:45,
                    from include/linux/highmem.h:5,
                    from include/linux/bvec.h:10,
                    from include/linux/blk_types.h:10,
                    from include/linux/bio.h:10,
                    from drivers/md/bcache/bcache.h:181,
                    from drivers/md/bcache/super.c:10:
   include/linux/slab.h:210:6: note: previous declaration of 'kfree' with type 'void(const void *)'
     210 | void kfree(const void *objp);
         |      ^~~~~
   drivers/md/bcache/super.c:2632:9: warning: data definition has no type or storage class
    2632 |         kfree(path);
         |         ^~~~~
   drivers/md/bcache/super.c:2632:9: error: type defaults to 'int' in declaration of 'kfree' [-Werror=implicit-int]
   drivers/md/bcache/super.c:2632:9: warning: parameter names (without types) in function declaration
   drivers/md/bcache/super.c:2632:9: error: conflicting types for 'kfree'; have 'int()'
   include/linux/slab.h:210:6: note: previous declaration of 'kfree' with type 'void(const void *)'
     210 | void kfree(const void *objp);
         |      ^~~~~
   In file included from include/linux/linkage.h:7,
                    from include/linux/preempt.h:10,
                    from include/linux/spinlock.h:56,
                    from include/linux/wait.h:9,
                    from include/linux/mempool.h:8,
                    from include/linux/bio.h:8:
   include/linux/export.h:27:21: error: expected declaration specifiers or '...' before '(' token
      27 | #define THIS_MODULE (&__this_module)
         |                     ^
   drivers/md/bcache/super.c:2633:20: note: in expansion of macro 'THIS_MODULE'
    2633 |         module_put(THIS_MODULE);
         |                    ^~~~~~~~~~~
   drivers/md/bcache/super.c:2634:11: error: expected '=', ',', ';', 'asm' or '__attribute__' before ':' token
    2634 | async_done:
         |           ^
   drivers/md/bcache/super.c:2637:16: error: expected '=', ',', ';', 'asm' or '__attribute__' before ':' token
    2637 | out_free_holder:
         |                ^
   drivers/md/bcache/super.c:2639:16: error: expected '=', ',', ';', 'asm' or '__attribute__' before ':' token
    2639 | out_put_sb_page:
         |                ^
   drivers/md/bcache/super.c:2641:15: error: expected '=', ',', ';', 'asm' or '__attribute__' before ':' token
    2641 | out_blkdev_put:
         |               ^
   drivers/md/bcache/super.c:2643:12: error: expected '=', ',', ';', 'asm' or '__attribute__' before ':' token
    2643 | out_free_sb:
         |            ^
   drivers/md/bcache/super.c:2645:14: error: expected '=', ',', ';', 'asm' or '__attribute__' before ':' token
    2645 | out_free_path:
         |              ^
   drivers/md/bcache/super.c:2647:9: warning: data definition has no type or storage class
    2647 |         path = NULL;
         |         ^~~~
   drivers/md/bcache/super.c:2647:9: error: type defaults to 'int' in declaration of 'path' [-Werror=implicit-int]
   In file included from include/uapi/linux/posix_types.h:5,
                    from include/uapi/linux/types.h:14,
                    from include/linux/types.h:6,
                    from include/linux/kasan-checks.h:5,
                    from include/asm-generic/rwonce.h:26,
                    from arch/s390/include/asm/rwonce.h:29,
                    from include/linux/compiler.h:247,
                    from include/linux/build_bug.h:5,
                    from include/linux/container_of.h:5,
                    from include/linux/list.h:5,
                    from include/linux/wait.h:7:
   include/linux/stddef.h:8:14: warning: initialization of 'int' from 'void *' makes integer from pointer without a cast [-Wint-conversion]
       8 | #define NULL ((void *)0)
         |              ^
   drivers/md/bcache/super.c:2647:16: note: in expansion of macro 'NULL'


vim +/async_registration +2520 drivers/md/bcache/super.c

867f981b0739bd Jan Kara          2023-06-21  2509  
cafe563591446c Kent Overstreet   2013-03-23  2510  static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
cafe563591446c Kent Overstreet   2013-03-23  2511  			       const char *buffer, size_t size)
cafe563591446c Kent Overstreet   2013-03-23  2512  {
50246693f81fe8 Christoph Hellwig 2020-01-24  2513  	const char *err;
29cda393bcaad1 Coly Li           2020-01-24  2514  	char *path = NULL;
50246693f81fe8 Christoph Hellwig 2020-01-24  2515  	struct cache_sb *sb;
cfa0c56db9c087 Christoph Hellwig 2020-01-24  2516  	struct cache_sb_disk *sb_disk;
ee9eea7d8b1a83 Jan Kara          2023-06-21  2517  	struct block_device *bdev, *bdev2;
ee9eea7d8b1a83 Jan Kara          2023-06-21  2518  	void *holder = NULL;
50246693f81fe8 Christoph Hellwig 2020-01-24  2519  	ssize_t ret;
a58e88bfdc4d52 Coly Li           2020-10-01 @2520  	bool async_registration = false;
ee9eea7d8b1a83 Jan Kara          2023-06-21  2521  	bool quiet = false;
a58e88bfdc4d52 Coly Li           2020-10-01  2522  

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Re: [PATCH 2/2] bcache: Fix bcache device claiming

[kernel test robot]

Hi Jan,

kernel test robot noticed the following build errors:

[auto build test ERROR on axboe-block/for-6.5/block]
[also build test ERROR on next-20230621]
[cannot apply to linus/master hch-configfs/for-next v6.4-rc7]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Jan-Kara/bcache-Alloc-holder-object-before-async-registration/20230622-002543
base:   https://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git for-6.5/block
patch link:    https://lore.kernel.org/r/20230621162333.30027-2-jack%40suse.cz
patch subject: [PATCH 2/2] bcache: Fix bcache device claiming
config: i386-debian-10.3 (https://download.01.org/0day-ci/archive/20230622/202306221133.HFiLGynP-lkp@intel.com/config)
compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
reproduce: (https://download.01.org/0day-ci/archive/20230622/202306221133.HFiLGynP-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202306221133.HFiLGynP-lkp@intel.com/

All error/warnings (new ones prefixed by >>):

   drivers/md/bcache/super.c: In function 'register_bcache':
   drivers/md/bcache/super.c:2574:9: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
    2574 |         if (IS_ERR(bdev))
         |         ^~
   drivers/md/bcache/super.c:2576:17: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'
    2576 |                 if (bdev == ERR_PTR(-EBUSY)) {
         |                 ^~
   drivers/md/bcache/super.c:2591:17: error: label 'out_free_holder' used but not defined
    2591 |                 goto out_free_holder;
         |                 ^~~~
   drivers/md/bcache/super.c:2566:17: error: label 'out_put_sb_page' used but not defined
    2566 |                 goto out_put_sb_page;
         |                 ^~~~
   drivers/md/bcache/super.c:2560:17: error: label 'out_blkdev_put' used but not defined
    2560 |                 goto out_blkdev_put;
         |                 ^~~~
   drivers/md/bcache/super.c:2552:17: error: label 'out_free_sb' used but not defined
    2552 |                 goto out_free_sb;
         |                 ^~~~
   drivers/md/bcache/super.c:2546:17: error: label 'out_free_path' used but not defined
    2546 |                 goto out_free_path;
         |                 ^~~~
   drivers/md/bcache/super.c:2542:17: error: label 'out_module_put' used but not defined
    2542 |                 goto out_module_put;
         |                 ^~~~
   drivers/md/bcache/super.c:2530:17: error: label 'out' used but not defined
    2530 |                 goto out;
         |                 ^~~~
   drivers/md/bcache/super.c:2521:14: warning: variable 'quiet' set but not used [-Wunused-but-set-variable]
    2521 |         bool quiet = false;
         |              ^~~~~
>> drivers/md/bcache/super.c:2520:14: warning: unused variable 'async_registration' [-Wunused-variable]
    2520 |         bool async_registration = false;
         |              ^~~~~~~~~~~~~~~~~~
   drivers/md/bcache/super.c:2519:17: warning: variable 'ret' set but not used [-Wunused-but-set-variable]
    2519 |         ssize_t ret;
         |                 ^~~
   drivers/md/bcache/super.c:2592:9: error: no return statement in function returning non-void [-Werror=return-type]
    2592 |         }
         |         ^
   drivers/md/bcache/super.c: At top level:
   drivers/md/bcache/super.c:2594:9: warning: data definition has no type or storage class
    2594 |         err = "failed to register device";
         |         ^~~
   drivers/md/bcache/super.c:2594:9: error: type defaults to 'int' in declaration of 'err' [-Werror=implicit-int]
   drivers/md/bcache/super.c:2594:15: warning: initialization of 'int' from 'char *' makes integer from pointer without a cast [-Wint-conversion]
    2594 |         err = "failed to register device";
         |               ^~~~~~~~~~~~~~~~~~~~~~~~~~~
   drivers/md/bcache/super.c:2596:9: error: expected identifier or '(' before 'if'
    2596 |         if (async_registration) {
         |         ^~
   drivers/md/bcache/super.c:2617:9: error: expected identifier or '(' before 'if'
    2617 |         if (SB_IS_BDEV(sb)) {
         |         ^~
   drivers/md/bcache/super.c:2624:11: error: expected identifier or '(' before 'else'
    2624 |         } else {
         |           ^~~~
   drivers/md/bcache/super.c:2631:9: warning: data definition has no type or storage class
    2631 |         kfree(sb);
         |         ^~~~~
   drivers/md/bcache/super.c:2631:9: error: type defaults to 'int' in declaration of 'kfree' [-Werror=implicit-int]
   drivers/md/bcache/super.c:2631:9: warning: parameter names (without types) in function declaration
   drivers/md/bcache/super.c:2631:9: error: conflicting types for 'kfree'; have 'int()'
   In file included from include/linux/fs.h:45,
                    from include/linux/highmem.h:5,
                    from include/linux/bvec.h:10,
                    from include/linux/blk_types.h:10,
                    from include/linux/bio.h:10,
                    from drivers/md/bcache/bcache.h:181,
                    from drivers/md/bcache/super.c:10:
   include/linux/slab.h:210:6: note: previous declaration of 'kfree' with type 'void(const void *)'
     210 | void kfree(const void *objp);
         |      ^~~~~
   drivers/md/bcache/super.c:2632:9: warning: data definition has no type or storage class
    2632 |         kfree(path);
         |         ^~~~~
   drivers/md/bcache/super.c:2632:9: error: type defaults to 'int' in declaration of 'kfree' [-Werror=implicit-int]
   drivers/md/bcache/super.c:2632:9: warning: parameter names (without types) in function declaration
   drivers/md/bcache/super.c:2632:9: error: conflicting types for 'kfree'; have 'int()'
   include/linux/slab.h:210:6: note: previous declaration of 'kfree' with type 'void(const void *)'
     210 | void kfree(const void *objp);
         |      ^~~~~
   In file included from include/linux/linkage.h:7,
                    from include/linux/preempt.h:10,
                    from include/linux/spinlock.h:56,
                    from include/linux/wait.h:9,
                    from include/linux/mempool.h:8,
                    from include/linux/bio.h:8:
   include/linux/export.h:27:21: error: expected declaration specifiers or '...' before '(' token
      27 | #define THIS_MODULE (&__this_module)
         |                     ^
   drivers/md/bcache/super.c:2633:20: note: in expansion of macro 'THIS_MODULE'
    2633 |         module_put(THIS_MODULE);
         |                    ^~~~~~~~~~~
   drivers/md/bcache/super.c:2634:11: error: expected '=', ',', ';', 'asm' or '__attribute__' before ':' token
    2634 | async_done:
         |           ^
   drivers/md/bcache/super.c:2637:16: error: expected '=', ',', ';', 'asm' or '__attribute__' before ':' token
    2637 | out_free_holder:
         |                ^
   drivers/md/bcache/super.c:2639:16: error: expected '=', ',', ';', 'asm' or '__attribute__' before ':' token
    2639 | out_put_sb_page:
         |                ^
   In file included from arch/x86/include/asm/page.h:85,
                    from arch/x86/include/asm/thread_info.h:12,
                    from include/linux/thread_info.h:60,
                    from arch/x86/include/asm/preempt.h:9,
                    from include/linux/preempt.h:78:
>> include/asm-generic/memory_model.h:55:2: error: expected identifier or '(' before ')' token
      55 | })
         |  ^
   include/asm-generic/memory_model.h:65:21: note: in expansion of macro '__pfn_to_page'
      65 | #define pfn_to_page __pfn_to_page
         |                     ^~~~~~~~~~~~~
   arch/x86/include/asm/page.h:68:33: note: in expansion of macro 'pfn_to_page'
      68 | #define virt_to_page(kaddr)     pfn_to_page(__pa(kaddr) >> PAGE_SHIFT)
         |                                 ^~~~~~~~~~~
   drivers/md/bcache/super.c:2640:18: note: in expansion of macro 'virt_to_page'
    2640 |         put_page(virt_to_page(sb_disk));
         |                  ^~~~~~~~~~~~
   drivers/md/bcache/super.c:2641:15: error: expected '=', ',', ';', 'asm' or '__attribute__' before ':' token
    2641 | out_blkdev_put:
         |               ^
   drivers/md/bcache/super.c:2643:12: error: expected '=', ',', ';', 'asm' or '__attribute__' before ':' token
    2643 | out_free_sb:
         |            ^
   drivers/md/bcache/super.c:2645:14: error: expected '=', ',', ';', 'asm' or '__attribute__' before ':' token
    2645 | out_free_path:
         |              ^
   drivers/md/bcache/super.c:2647:9: warning: data definition has no type or storage class
    2647 |         path = NULL;
         |         ^~~~
   drivers/md/bcache/super.c:2647:9: error: type defaults to 'int' in declaration of 'path' [-Werror=implicit-int]
   In file included from include/uapi/linux/posix_types.h:5,
                    from include/uapi/linux/types.h:14,
                    from include/linux/types.h:6,
                    from include/linux/kasan-checks.h:5,
                    from include/asm-generic/rwonce.h:26,
                    from ./arch/x86/include/generated/asm/rwonce.h:1,
                    from include/linux/compiler.h:247,
                    from include/linux/build_bug.h:5,
                    from include/linux/container_of.h:5,
                    from include/linux/list.h:5,
                    from include/linux/wait.h:7:
   include/linux/stddef.h:8:14: warning: initialization of 'int' from 'void *' makes integer from pointer without a cast [-Wint-conversion]
       8 | #define NULL ((void *)0)
         |              ^
   drivers/md/bcache/super.c:2647:16: note: in expansion of macro 'NULL'
    2647 |         path = NULL;
         |                ^~~~
   drivers/md/bcache/super.c:2648:15: error: expected '=', ',', ';', 'asm' or '__attribute__' before ':' token
    2648 | out_module_put:
         |               ^
   drivers/md/bcache/super.c:2650:4: error: expected '=', ',', ';', 'asm' or '__attribute__' before ':' token
    2650 | out:
         |    ^
   In file included from include/linux/kernel.h:30,
                    from arch/x86/include/asm/percpu.h:27,
                    from arch/x86/include/asm/preempt.h:6:
   include/linux/printk.h:428:10: error: expected identifier or '(' before ')' token
     428 |         })
         |          ^
   include/linux/printk.h:455:26: note: in expansion of macro 'printk_index_wrap'
     455 | #define printk(fmt, ...) printk_index_wrap(_printk, fmt, ##__VA_ARGS__)
         |                          ^~~~~~~~~~~~~~~~~
   include/linux/printk.h:528:9: note: in expansion of macro 'printk'
     528 |         printk(KERN_INFO pr_fmt(fmt), ##__VA_ARGS__)
         |         ^~~~~~
   drivers/md/bcache/super.c:2652:17: note: in expansion of macro 'pr_info'
    2652 |                 pr_info("error %s: %s\n", path?path:"", err);
         |                 ^~~~~~~
   drivers/md/bcache/super.c:2653:9: error: expected identifier or '(' before 'return'
    2653 |         return ret;
         |         ^~~~~~
   drivers/md/bcache/super.c:2654:1: error: expected identifier or '(' before '}' token
    2654 | }
         | ^
   drivers/md/bcache/super.c:2492:13: warning: 'register_device_async' defined but not used [-Wunused-function]
    2492 | static void register_device_async(struct async_reg_args *args)
         |             ^~~~~~~~~~~~~~~~~~~~~
   cc1: some warnings being treated as errors


vim +/async_registration +2520 drivers/md/bcache/super.c

867f981b0739bd Jan Kara          2023-06-21  2509  
cafe563591446c Kent Overstreet   2013-03-23  2510  static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
cafe563591446c Kent Overstreet   2013-03-23  2511  			       const char *buffer, size_t size)
cafe563591446c Kent Overstreet   2013-03-23  2512  {
50246693f81fe8 Christoph Hellwig 2020-01-24  2513  	const char *err;
29cda393bcaad1 Coly Li           2020-01-24  2514  	char *path = NULL;
50246693f81fe8 Christoph Hellwig 2020-01-24  2515  	struct cache_sb *sb;
cfa0c56db9c087 Christoph Hellwig 2020-01-24  2516  	struct cache_sb_disk *sb_disk;
ee9eea7d8b1a83 Jan Kara          2023-06-21  2517  	struct block_device *bdev, *bdev2;
ee9eea7d8b1a83 Jan Kara          2023-06-21  2518  	void *holder = NULL;
50246693f81fe8 Christoph Hellwig 2020-01-24  2519  	ssize_t ret;
a58e88bfdc4d52 Coly Li           2020-10-01 @2520  	bool async_registration = false;
ee9eea7d8b1a83 Jan Kara          2023-06-21  2521  	bool quiet = false;
a58e88bfdc4d52 Coly Li           2020-10-01  2522  
a58e88bfdc4d52 Coly Li           2020-10-01  2523  #ifdef CONFIG_BCACHE_ASYNC_REGISTRATION
a58e88bfdc4d52 Coly Li           2020-10-01  2524  	async_registration = true;
a58e88bfdc4d52 Coly Li           2020-10-01  2525  #endif
cafe563591446c Kent Overstreet   2013-03-23  2526  
50246693f81fe8 Christoph Hellwig 2020-01-24  2527  	ret = -EBUSY;
29cda393bcaad1 Coly Li           2020-01-24  2528  	err = "failed to reference bcache module";
cafe563591446c Kent Overstreet   2013-03-23  2529  	if (!try_module_get(THIS_MODULE))
50246693f81fe8 Christoph Hellwig 2020-01-24  2530  		goto out;
cafe563591446c Kent Overstreet   2013-03-23  2531  
a59ff6ccc2bf2e Coly Li           2019-06-28  2532  	/* For latest state of bcache_is_reboot */
a59ff6ccc2bf2e Coly Li           2019-06-28  2533  	smp_mb();
29cda393bcaad1 Coly Li           2020-01-24  2534  	err = "bcache is in reboot";
a59ff6ccc2bf2e Coly Li           2019-06-28  2535  	if (bcache_is_reboot)
50246693f81fe8 Christoph Hellwig 2020-01-24  2536  		goto out_module_put;
a59ff6ccc2bf2e Coly Li           2019-06-28  2537  
50246693f81fe8 Christoph Hellwig 2020-01-24  2538  	ret = -ENOMEM;
50246693f81fe8 Christoph Hellwig 2020-01-24  2539  	err = "cannot allocate memory";
a56489d4b3c914 Florian Schmaus   2018-07-26  2540  	path = kstrndup(buffer, size, GFP_KERNEL);
a56489d4b3c914 Florian Schmaus   2018-07-26  2541  	if (!path)
50246693f81fe8 Christoph Hellwig 2020-01-24 @2542  		goto out_module_put;
a56489d4b3c914 Florian Schmaus   2018-07-26  2543  
a56489d4b3c914 Florian Schmaus   2018-07-26  2544  	sb = kmalloc(sizeof(struct cache_sb), GFP_KERNEL);
a56489d4b3c914 Florian Schmaus   2018-07-26  2545  	if (!sb)
50246693f81fe8 Christoph Hellwig 2020-01-24  2546  		goto out_free_path;
cafe563591446c Kent Overstreet   2013-03-23  2547  
50246693f81fe8 Christoph Hellwig 2020-01-24  2548  	ret = -EINVAL;
cafe563591446c Kent Overstreet   2013-03-23  2549  	err = "failed to open device";
ee9eea7d8b1a83 Jan Kara          2023-06-21  2550  	bdev = blkdev_get_by_path(strim(path), BLK_OPEN_READ, NULL, NULL);
ee9eea7d8b1a83 Jan Kara          2023-06-21  2551  	if (IS_ERR(bdev))
50246693f81fe8 Christoph Hellwig 2020-01-24  2552  		goto out_free_sb;
f59fce847fc848 Kent Overstreet   2013-05-15  2553  
f59fce847fc848 Kent Overstreet   2013-05-15  2554  	err = "failed to set blocksize";
f59fce847fc848 Kent Overstreet   2013-05-15  2555  	if (set_blocksize(bdev, 4096))
50246693f81fe8 Christoph Hellwig 2020-01-24  2556  		goto out_blkdev_put;
cafe563591446c Kent Overstreet   2013-03-23  2557  
cfa0c56db9c087 Christoph Hellwig 2020-01-24  2558  	err = read_super(sb, bdev, &sb_disk);
cafe563591446c Kent Overstreet   2013-03-23  2559  	if (err)
50246693f81fe8 Christoph Hellwig 2020-01-24  2560  		goto out_blkdev_put;
cafe563591446c Kent Overstreet   2013-03-23  2561  
867f981b0739bd Jan Kara          2023-06-21  2562  	holder = alloc_holder_object(sb);
867f981b0739bd Jan Kara          2023-06-21  2563  	if (!holder) {
867f981b0739bd Jan Kara          2023-06-21  2564  		ret = -ENOMEM;
867f981b0739bd Jan Kara          2023-06-21  2565  		err = "cannot allocate memory";
867f981b0739bd Jan Kara          2023-06-21  2566  		goto out_put_sb_page;
867f981b0739bd Jan Kara          2023-06-21  2567  	}
867f981b0739bd Jan Kara          2023-06-21  2568  
ee9eea7d8b1a83 Jan Kara          2023-06-21  2569  	/* Now reopen in exclusive mode with proper holder */
ee9eea7d8b1a83 Jan Kara          2023-06-21  2570  	bdev2 = blkdev_get_by_dev(bdev->bd_dev, BLK_OPEN_READ | BLK_OPEN_WRITE,
ee9eea7d8b1a83 Jan Kara          2023-06-21  2571  				  holder, NULL);
ee9eea7d8b1a83 Jan Kara          2023-06-21  2572  	blkdev_put(bdev, NULL);
ee9eea7d8b1a83 Jan Kara          2023-06-21  2573  	bdev = bdev2;
ee9eea7d8b1a83 Jan Kara          2023-06-21  2574  	if (IS_ERR(bdev))
ee9eea7d8b1a83 Jan Kara          2023-06-21  2575  		ret = PTR_ERR(bdev);
ee9eea7d8b1a83 Jan Kara          2023-06-21  2576  		if (bdev == ERR_PTR(-EBUSY)) {
ee9eea7d8b1a83 Jan Kara          2023-06-21  2577  			dev_t dev;
ee9eea7d8b1a83 Jan Kara          2023-06-21  2578  
ee9eea7d8b1a83 Jan Kara          2023-06-21  2579  			mutex_lock(&bch_register_lock);
ee9eea7d8b1a83 Jan Kara          2023-06-21  2580  			if (lookup_bdev(strim(path), &dev) == 0 &&
ee9eea7d8b1a83 Jan Kara          2023-06-21  2581  			    bch_is_open(dev))
ee9eea7d8b1a83 Jan Kara          2023-06-21  2582  				err = "device already registered";
ee9eea7d8b1a83 Jan Kara          2023-06-21  2583  			else
ee9eea7d8b1a83 Jan Kara          2023-06-21  2584  				err = "device busy";
ee9eea7d8b1a83 Jan Kara          2023-06-21  2585  			mutex_unlock(&bch_register_lock);
ee9eea7d8b1a83 Jan Kara          2023-06-21  2586  			if (attr == &ksysfs_register_quiet) {
ee9eea7d8b1a83 Jan Kara          2023-06-21  2587  				quiet = true;
ee9eea7d8b1a83 Jan Kara          2023-06-21  2588  				ret = size;
ee9eea7d8b1a83 Jan Kara          2023-06-21  2589  			}
ee9eea7d8b1a83 Jan Kara          2023-06-21  2590  		}
ee9eea7d8b1a83 Jan Kara          2023-06-21  2591  		goto out_free_holder;
ee9eea7d8b1a83 Jan Kara          2023-06-21  2592  	}
ee9eea7d8b1a83 Jan Kara          2023-06-21  2593  
cc40daf91bdddb Tang Junhui       2018-03-05  2594  	err = "failed to register device";
a58e88bfdc4d52 Coly Li           2020-10-01  2595  
a58e88bfdc4d52 Coly Li           2020-10-01  2596  	if (async_registration) {
9e23ccf8f0a22e Coly Li           2020-05-27  2597  		/* register in asynchronous way */
9e23ccf8f0a22e Coly Li           2020-05-27  2598  		struct async_reg_args *args =
9e23ccf8f0a22e Coly Li           2020-05-27  2599  			kzalloc(sizeof(struct async_reg_args), GFP_KERNEL);
9e23ccf8f0a22e Coly Li           2020-05-27  2600  
9e23ccf8f0a22e Coly Li           2020-05-27  2601  		if (!args) {
9e23ccf8f0a22e Coly Li           2020-05-27  2602  			ret = -ENOMEM;
9e23ccf8f0a22e Coly Li           2020-05-27  2603  			err = "cannot allocate memory";
867f981b0739bd Jan Kara          2023-06-21  2604  			goto out_free_holder;
9e23ccf8f0a22e Coly Li           2020-05-27  2605  		}
9e23ccf8f0a22e Coly Li           2020-05-27  2606  
9e23ccf8f0a22e Coly Li           2020-05-27  2607  		args->path	= path;
9e23ccf8f0a22e Coly Li           2020-05-27  2608  		args->sb	= sb;
9e23ccf8f0a22e Coly Li           2020-05-27  2609  		args->sb_disk	= sb_disk;
9e23ccf8f0a22e Coly Li           2020-05-27  2610  		args->bdev	= bdev;
867f981b0739bd Jan Kara          2023-06-21  2611  		args->holder	= holder;
d7fae7b4fa1527 Kai Krakow        2021-02-10  2612  		register_device_async(args);
9e23ccf8f0a22e Coly Li           2020-05-27  2613  		/* No wait and returns to user space */
9e23ccf8f0a22e Coly Li           2020-05-27  2614  		goto async_done;
9e23ccf8f0a22e Coly Li           2020-05-27  2615  	}
9e23ccf8f0a22e Coly Li           2020-05-27  2616  
2903381fce7100 Kent Overstreet   2013-04-11  2617  	if (SB_IS_BDEV(sb)) {
4fa03402cda2fa Kent Overstreet   2014-03-17  2618  		mutex_lock(&bch_register_lock);
867f981b0739bd Jan Kara          2023-06-21  2619  		ret = register_bdev(sb, sb_disk, bdev, holder);
4fa03402cda2fa Kent Overstreet   2014-03-17  2620  		mutex_unlock(&bch_register_lock);
bb6d355c2aff42 Coly Li           2019-04-25  2621  		/* blkdev_put() will be called in cached_dev_free() */
fc8f19cc5dce18 Christoph Hellwig 2020-01-24  2622  		if (ret < 0)
fc8f19cc5dce18 Christoph Hellwig 2020-01-24  2623  			goto out_free_sb;
cafe563591446c Kent Overstreet   2013-03-23  2624  	} else {
bb6d355c2aff42 Coly Li           2019-04-25  2625  		/* blkdev_put() will be called in bch_cache_release() */
867f981b0739bd Jan Kara          2023-06-21  2626  		ret = register_cache(sb, sb_disk, bdev, holder);
d55f7cb2e5c053 Chao Yu           2021-10-20  2627  		if (ret)
fc8f19cc5dce18 Christoph Hellwig 2020-01-24  2628  			goto out_free_sb;
50246693f81fe8 Christoph Hellwig 2020-01-24  2629  	}
50246693f81fe8 Christoph Hellwig 2020-01-24  2630  
f59fce847fc848 Kent Overstreet   2013-05-15  2631  	kfree(sb);
f59fce847fc848 Kent Overstreet   2013-05-15  2632  	kfree(path);
f59fce847fc848 Kent Overstreet   2013-05-15  2633  	module_put(THIS_MODULE);
9e23ccf8f0a22e Coly Li           2020-05-27  2634  async_done:
50246693f81fe8 Christoph Hellwig 2020-01-24  2635  	return size;
f59fce847fc848 Kent Overstreet   2013-05-15  2636  
867f981b0739bd Jan Kara          2023-06-21  2637  out_free_holder:
867f981b0739bd Jan Kara          2023-06-21  2638  	kfree(holder);
50246693f81fe8 Christoph Hellwig 2020-01-24  2639  out_put_sb_page:
cfa0c56db9c087 Christoph Hellwig 2020-01-24  2640  	put_page(virt_to_page(sb_disk));
50246693f81fe8 Christoph Hellwig 2020-01-24  2641  out_blkdev_put:
ee9eea7d8b1a83 Jan Kara          2023-06-21  2642  	blkdev_put(bdev, holder);
50246693f81fe8 Christoph Hellwig 2020-01-24  2643  out_free_sb:
50246693f81fe8 Christoph Hellwig 2020-01-24  2644  	kfree(sb);
50246693f81fe8 Christoph Hellwig 2020-01-24  2645  out_free_path:
50246693f81fe8 Christoph Hellwig 2020-01-24  2646  	kfree(path);
ae3cd299919af6 Coly Li           2020-01-24  2647  	path = NULL;
50246693f81fe8 Christoph Hellwig 2020-01-24  2648  out_module_put:
50246693f81fe8 Christoph Hellwig 2020-01-24  2649  	module_put(THIS_MODULE);
50246693f81fe8 Christoph Hellwig 2020-01-24  2650  out:
ee9eea7d8b1a83 Jan Kara          2023-06-21  2651  	if (!quiet)
46f5aa8806e34f Joe Perches       2020-05-27  2652  		pr_info("error %s: %s\n", path?path:"", err);
50246693f81fe8 Christoph Hellwig 2020-01-24  2653  	return ret;
cafe563591446c Kent Overstreet   2013-03-23  2654  }
cafe563591446c Kent Overstreet   2013-03-23  2655  

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Re: [PATCH 2/2] bcache: Fix bcache device claiming

[Christoph Hellwig]

On Wed, Jun 21, 2023 at 06:23:27PM +0200, Jan Kara wrote:
> Commit 2736e8eeb0cc ("block: use the holder as indication for exclusive
> opens") introduced a change that blkdev_put() has to get exclusive
> holder of the bdev as an argument. However it overlooked that
> register_bdev() and register_cache() overwrite the bdev->bd_holder field
> in the block device to point to the real owning object which was not
> available at the time we called blkdev_get_by_path(). Messing with bdev
> internals like this is a layering violation and it also causes
> blkdev_put() to issue warning about mismatching holders.

Ugg, yes.

> Fix bcache to reopen the block device with appropriate holder once it is
> available which also restores the behavior that multiple bcache caches
> cannot claim the same device which was also broken by commit
> 2736e8eeb0cc.

That was actually an intentional and documented change in commit
29499ab060fe ("bcache: don't pass a stack address to
blkdev_get_by_path") because the old behavior was broken already in
addition to the changing of the block stuff underneath.  Not that I'm
arguing against your changes here, but the commit log probably needs a
bit of tweaking.