From: Coly Li <colyli@suse.de>
To: linux-bcache@vger.kernel.org, axboe@kernel.dk
Cc: linux-block@vger.kernel.org, Shenghui Wang <shhuiw@foxmail.com>,
Coly Li <colyli@suse.de>
Subject: [PATCH 06/12] bcache: cannot set writeback_running via sysfs if no writeback kthread created
Date: Thu, 13 Dec 2018 22:53:51 +0800 [thread overview]
Message-ID: <20181213145357.38528-7-colyli@suse.de> (raw)
In-Reply-To: <20181213145357.38528-1-colyli@suse.de>
From: Shenghui Wang <shhuiw@foxmail.com>
"echo 1 > writeback_running" marks writeback_running even if no writeback
kthread created as "d_strtoul(writeback_running)" will simply set dc->
writeback_running without checking the existence of dc->writeback_thread.
Add check for setting writeback_running via sysfs: if no writeback kthread
available, reject setting to 1.
v2 -> v3:
* Make message on wrong assignment more clear.
* Print name of bcache device instead of name of backing device.
Signed-off-by: Shenghui Wang <shhuiw@foxmail.com>
Signed-off-by: Coly Li <colyli@suse.de>
---
drivers/md/bcache/sysfs.c | 21 +++++++++++++++++++--
1 file changed, 19 insertions(+), 2 deletions(-)
diff --git a/drivers/md/bcache/sysfs.c b/drivers/md/bcache/sysfs.c
index d2e5c9892d4d..9d5fe12f0c9c 100644
--- a/drivers/md/bcache/sysfs.c
+++ b/drivers/md/bcache/sysfs.c
@@ -384,8 +384,25 @@ STORE(bch_cached_dev)
mutex_lock(&bch_register_lock);
size = __cached_dev_store(kobj, attr, buf, size);
- if (attr == &sysfs_writeback_running)
- bch_writeback_queue(dc);
+ if (attr == &sysfs_writeback_running) {
+ /* dc->writeback_running changed in __cached_dev_store() */
+ if (IS_ERR_OR_NULL(dc->writeback_thread)) {
+ /*
+ * reject setting it to 1 via sysfs if writeback
+ * kthread is not created yet.
+ */
+ if (dc->writeback_running) {
+ dc->writeback_running = false;
+ pr_err("%s: failed to run non-existent writeback thread",
+ dc->disk.disk->disk_name);
+ }
+ } else
+ /*
+ * writeback kthread will check if dc->writeback_running
+ * is true or false.
+ */
+ bch_writeback_queue(dc);
+ }
if (attr == &sysfs_writeback_percent)
if (!test_and_set_bit(BCACHE_DEV_WB_RUNNING, &dc->disk.flags))
--
2.16.4
next prev parent reply other threads:[~2018-12-13 14:55 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-13 14:53 [PATCH 00/12] bcache patches for Linux v4.21 Coly Li
2018-12-13 14:53 ` [PATCH 01/12] bcache: add comment for cache_set->fill_iter Coly Li
2018-12-13 14:53 ` [PATCH 02/12] bcache: do not check if debug dentry is ERR or NULL explicitly on remove Coly Li
2018-12-13 14:53 ` [PATCH 03/12] bcache: update comment for bch_data_insert Coly Li
2018-12-13 14:53 ` [PATCH 04/12] bcache: update comment in sysfs.c Coly Li
2018-12-13 14:53 ` [PATCH 05/12] bcache: do not mark writeback_running until backing dev attached to cache_set Coly Li
2018-12-13 14:53 ` Coly Li [this message]
2018-12-13 14:53 ` [PATCH 07/12] bcache: introduce force_wake_up_gc() Coly Li
2018-12-13 14:53 ` [PATCH 08/12] bcache: option to automatically run gc thread after writeback accomplished Coly Li
2018-12-13 14:53 ` [PATCH 09/12] bcache: add MODULE_DESCRIPTION information Coly Li
2018-12-13 14:53 ` [PATCH 10/12] bcache: make cutoff_writeback and cutoff_writeback_sync tunnable Coly Li
2018-12-13 14:53 ` [PATCH 11/12] bcache: set writeback_percent in a flexible range Coly Li
2018-12-13 14:53 ` [PATCH 12/12] bcache: print number of keys in trace_bcache_journal_write Coly Li
2018-12-13 15:16 ` [PATCH 00/12] bcache patches for Linux v4.21 Jens Axboe
2018-12-14 8:25 ` Coly Li
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