diff --git a/fs/btrfs/sysfs.c b/fs/btrfs/sysfs.c index b2f653eb46cb99645e00d07cd6ecffdd6660f17e..620fddfd7096cc53bc7c9358b6d6083a8497c8fe 100644 --- a/fs/btrfs/sysfs.c +++ b/fs/btrfs/sysfs.c @@ -907,6 +907,54 @@ static bool strmatch(const char *buffer, const char *string) return false; } +static const char * const btrfs_read_policy_name[] = { "pid" }; + +static ssize_t btrfs_read_policy_show(struct kobject *kobj, + struct kobj_attribute *a, char *buf) +{ + struct btrfs_fs_devices *fs_devices = to_fs_devs(kobj); + ssize_t ret = 0; + int i; + + for (i = 0; i < BTRFS_NR_READ_POLICY; i++) { + if (fs_devices->read_policy == i) + ret += scnprintf(buf + ret, PAGE_SIZE - ret, "%s[%s]", + (ret == 0 ? "" : " "), + btrfs_read_policy_name[i]); + else + ret += scnprintf(buf + ret, PAGE_SIZE - ret, "%s%s", + (ret == 0 ? "" : " "), + btrfs_read_policy_name[i]); + } + + ret += scnprintf(buf + ret, PAGE_SIZE - ret, "\n"); + + return ret; +} + +static ssize_t btrfs_read_policy_store(struct kobject *kobj, + struct kobj_attribute *a, + const char *buf, size_t len) +{ + struct btrfs_fs_devices *fs_devices = to_fs_devs(kobj); + int i; + + for (i = 0; i < BTRFS_NR_READ_POLICY; i++) { + if (strmatch(buf, btrfs_read_policy_name[i])) { + if (i != fs_devices->read_policy) { + fs_devices->read_policy = i; + btrfs_info(fs_devices->fs_info, + "read policy set to '%s'", + btrfs_read_policy_name[i]); + } + return len; + } + } + + return -EINVAL; +} +BTRFS_ATTR_RW(, read_policy, btrfs_read_policy_show, btrfs_read_policy_store); + static const struct attribute *btrfs_attrs[] = { BTRFS_ATTR_PTR(, label), BTRFS_ATTR_PTR(, nodesize), @@ -917,6 +965,7 @@ static const struct attribute *btrfs_attrs[] = { BTRFS_ATTR_PTR(, checksum), BTRFS_ATTR_PTR(, exclusive_operation), BTRFS_ATTR_PTR(, generation), + BTRFS_ATTR_PTR(, read_policy), NULL, };