Re: [PATCH] add label interface for cache device in sysfs
From: Coly Li <hidden>
Date: 2018-09-14 10:00:41
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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 <redacted>
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
quoted hunk ↗ jump to hunk
--- 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);