[PATCH 0/1] bcache fix for 4.17-rc6

[PATCH 0/1] bcache fix for 4.17-rc6

[Coly Li]

Hi Jenns,

We have reports that bcache does not work when CONFIG_DEBUG_FS=n, here is
the bug report on bugzilla.kernel.org:
	https://bugzilla.kernel.org/show_bug.cgi?id=199683
This problem happens since v4.16 and I believe it still happens in v4.17.

This submission has one patch to fix this issue, the patch is tested by
one of the reporters. If it is not too late for 4.17, could you please to
pick it for 4.17-rc6 ?

Thanks in advance.

Coly Li
---

Coly Li (1):
  bcache: return 0 from bch_debug_init() if CONFIG_DEBUG_FS=n

 drivers/md/bcache/debug.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

-- 
2.16.3

[PATCH 1/1] bcache: return 0 from bch_debug_init() if CONFIG_DEBUG_FS=n

[Coly Li]

Commit 539d39eb2708 ("bcache: fix wrong return value in bch_debug_init()")
returns the return value of debugfs_create_dir() to bcache_init(). When
CONFIG_DEBUG_FS=n, bch_debug_init() always returns 1 and makes
bcache_init() failedi.

This patch makes bch_debug_init() always returns 0 if CONFIG_DEBUG_FS=n,
so bcache can continue to work for the kernels which don't have debugfs
enanbled.

Changelog:
v4: Add Acked-by from Kent Overstreet.
v3: Use IS_ENABLED(CONFIG_DEBUG_FS) to replace #ifdef DEBUG_FS.
v2: Remove a warning information
v1: Initial version.

Fixes: Commit 539d39eb2708 ("bcache: fix wrong return value in bch_debug_init()")
Cc: stable@vger.kernel.org
Signed-off-by: Coly Li <colyli@suse.de>
Reported-by: Massimo B. <massimo.b@gmx.net>
Reported-by: Kai Krakow <kai@kaishome.de>
Tested-by: Kai Krakow <kai@kaishome.de>
Acked-by: Kent Overstreet <kent.overstreet@gmail.com>
---
 drivers/md/bcache/debug.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/md/bcache/debug.c b/drivers/md/bcache/debug.c
index 4e63c6f6c04d..d030ce3025a6 100644
--- a/drivers/md/bcache/debug.c
+++ b/drivers/md/bcache/debug.c
@@ -250,7 +250,9 @@ void bch_debug_exit(void)
 
 int __init bch_debug_init(struct kobject *kobj)
 {
-	bcache_debug = debugfs_create_dir("bcache", NULL);
+	if (!IS_ENABLED(CONFIG_DEBUG_FS))
+		return 0;
 
+	bcache_debug = debugfs_create_dir("bcache", NULL);
 	return IS_ERR_OR_NULL(bcache_debug);
 }
-- 
2.16.3

Re: [PATCH 1/1] bcache: return 0 from bch_debug_init() if CONFIG_DEBUG_FS=n

[Jens Axboe]

On 5/17/18 9:33 AM, Coly Li wrote:
> Commit 539d39eb2708 ("bcache: fix wrong return value in bch_debug_init()")
> returns the return value of debugfs_create_dir() to bcache_init(). When
> CONFIG_DEBUG_FS=n, bch_debug_init() always returns 1 and makes
> bcache_init() failedi.
> 
> This patch makes bch_debug_init() always returns 0 if CONFIG_DEBUG_FS=n,
> so bcache can continue to work for the kernels which don't have debugfs
> enanbled.

Applied, thanks.


-- 
Jens Axboe