3.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Tang Junhui <tang.junhui@xxxxxxxxxx> [ Upstream commit 7f4fc93d4713394ee8f1cd44c238e046e11b4f15 ] I attach a back-end device to a cache set, and the cache set is not registered yet, this back-end device did not attach successfully, and no error returned: [root]# echo 87859280-fec6-4bcc-20df7ca8f86b > /sys/block/sde/bcache/attach [root]# In sysfs_attach(), the return value "v" is initialized to "size" in the beginning, and if no cache set exist in bch_cache_sets, the "v" value would not change any more, and return to sysfs, sysfs regard it as success since the "size" is a positive number. This patch fixes this issue by assigning "v" with "-ENOENT" in the initialization. Signed-off-by: Tang Junhui <tang.junhui@xxxxxxxxxx> Reviewed-by: Michael Lyle <mlyle@xxxxxxxx> Signed-off-by: Jens Axboe <axboe@xxxxxxxxx> Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/md/bcache/sysfs.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) --- a/drivers/md/bcache/sysfs.c +++ b/drivers/md/bcache/sysfs.c @@ -191,7 +191,7 @@ STORE(__cached_dev) { struct cached_dev *dc = container_of(kobj, struct cached_dev, disk.kobj); - ssize_t v = size; + ssize_t v; struct cache_set *c; struct kobj_uevent_env *env; @@ -268,6 +268,7 @@ STORE(__cached_dev) if (bch_parse_uuid(buf, set_uuid) < 16) return -EINVAL; + v = -ENOENT; list_for_each_entry(c, &bch_cache_sets, list) { v = bch_cached_dev_attach(dc, c, set_uuid); if (!v) @@ -275,7 +276,7 @@ STORE(__cached_dev) } pr_err("Can't attach %s: cache set not found", buf); - size = v; + return v; } if (attr == &sysfs_detach && dc->disk.c)