2018-09-14 09:52:12

by Dongbo Cao

Subject: [PATCH] add label interface for cache device in sysfs

label interface will be called by bcache tools in user space.

Signed-off-by: Dongbo Cao <[email protected]>
---
drivers/md/bcache/sysfs.c | 19 +++++++++++++++++++
1 file changed, 19 insertions(+)

diff --git a/drivers/md/bcache/sysfs.c b/drivers/md/bcache/sysfs.c
index 225b15aa..e64c718f 100644
--- a/drivers/md/bcache/sysfs.c
+++ b/drivers/md/bcache/sysfs.c
@@ -950,6 +950,13 @@ SHOW(__bch_cache)
return ret;
}

+ if (attr == &sysfs_label) {
+ memcpy(buf, ca->sb.label, SB_LABEL_SIZE);
+ buf[SB_LABEL_SIZE + 1] = '\0';
+ strcat(buf, "\n");
+ return strlen(buf);
+ }
+
return 0;
}
SHOW_LOCKED(bch_cache)
@@ -993,6 +1000,17 @@ STORE(__bch_cache)
atomic_set(&ca->io_errors, 0);
}

+ if (attr == &sysfs_label) {
+ if (size > SB_LABEL_SIZE)
+ return -EINVAL;
+ memcpy(ca->sb.label, buf, size);
+ if (size < SB_LABEL_SIZE)
+ ca->sb.label[size] = '\0';
+ if (size && ca->sb.label[size - 1] == '\n')
+ ca->sb.label[size - 1] = '\0';
+ bcache_write_super(ca->set);
+ }
+
return size;
}
STORE_LOCKED(bch_cache)
@@ -1009,6 +1027,7 @@ static struct attribute *bch_cache_files[] = {
&sysfs_io_errors,
&sysfs_clear_stats,
&sysfs_cache_replacement_policy,
+ &sysfs_label,
NULL
};
KTYPE(bch_cache);
--
2.17.1

2018-09-14 10:02:27

by Coly Li

Subject: Re: [PATCH] add label interface for cache device in sysfs

On 9/14/18 5:51 PM, Dongbo Cao wrote:
> label interface will be called by bcache tools in user space.
>
> Signed-off-by: Dongbo Cao <[email protected]>

Hi Dongbo,


In your change I see you set superblock label to cache set. What is the
use case for doing this ?

Thanks.


Coly Li


> ---
> drivers/md/bcache/sysfs.c | 19 +++++++++++++++++++
> 1 file changed, 19 insertions(+)
>
> diff --git a/drivers/md/bcache/sysfs.c b/drivers/md/bcache/sysfs.c
> index 225b15aa..e64c718f 100644
> --- a/drivers/md/bcache/sysfs.c
> +++ b/drivers/md/bcache/sysfs.c
> @@ -950,6 +950,13 @@ SHOW(__bch_cache)
> return ret;
> }
>
> + if (attr == &sysfs_label) {
> + memcpy(buf, ca->sb.label, SB_LABEL_SIZE);
> + buf[SB_LABEL_SIZE + 1] = '\0';
> + strcat(buf, "\n");
> + return strlen(buf);
> + }
> +
> return 0;
> }
> SHOW_LOCKED(bch_cache)
> @@ -993,6 +1000,17 @@ STORE(__bch_cache)
> atomic_set(&ca->io_errors, 0);
> }
>
> + if (attr == &sysfs_label) {
> + if (size > SB_LABEL_SIZE)
> + return -EINVAL;
> + memcpy(ca->sb.label, buf, size);
> + if (size < SB_LABEL_SIZE)
> + ca->sb.label[size] = '\0';
> + if (size && ca->sb.label[size - 1] == '\n')
> + ca->sb.label[size - 1] = '\0';
> + bcache_write_super(ca->set);
> + }
> +
> return size;
> }
> STORE_LOCKED(bch_cache)
> @@ -1009,6 +1027,7 @@ static struct attribute *bch_cache_files[] = {
> &sysfs_io_errors,
> &sysfs_clear_stats,
> &sysfs_cache_replacement_policy,
> + &sysfs_label,
> NULL
> };
> KTYPE(bch_cache);