btrfs: use BTRFS_ATTR instead of btrfs_no_store()

[cascardo/linux.git] / fs / btrfs / sysfs.c

diff --git a/fs/btrfs/sysfs.c b/fs/btrfs/sysfs.c
index 7869936..e6a851b 100644 (file)
--- a/fs/btrfs/sysfs.c
+++ b/fs/btrfs/sysfs.c
@@ -363,7 +363,8 @@ static ssize_t btrfs_label_show(struct kobject *kobj,
                                struct kobj_attribute *a, char *buf)
 {
        struct btrfs_fs_info *fs_info = to_fs_info(kobj);
-       return snprintf(buf, PAGE_SIZE, "%s\n", fs_info->super_copy->label);
+       char *label = fs_info->super_copy->label;
+       return snprintf(buf, PAGE_SIZE, label[0] ? "%s\n" : "%s", label);
 }
 
 static ssize_t btrfs_label_store(struct kobject *kobj,
@@ -374,8 +375,15 @@ static ssize_t btrfs_label_store(struct kobject *kobj,
        struct btrfs_trans_handle *trans;
        struct btrfs_root *root = fs_info->fs_root;
        int ret;
+       size_t p_len;
 
-       if (len >= BTRFS_LABEL_SIZE)
+       /*
+        * p_len is the len until the first occurrence of either
+        * '\n' or '\0'
+        */
+       p_len = strcspn(buf, "\n");
+
+       if (p_len >= BTRFS_LABEL_SIZE)
                return -EINVAL;
 
        trans = btrfs_start_transaction(root, 0);
@@ -383,7 +391,8 @@ static ssize_t btrfs_label_store(struct kobject *kobj,
                return PTR_ERR(trans);
 
        spin_lock(&root->fs_info->super_lock);
-       strcpy(fs_info->super_copy->label, buf);
+       memset(fs_info->super_copy->label, 0, BTRFS_LABEL_SIZE);
+       memcpy(fs_info->super_copy->label, buf, p_len);
        spin_unlock(&root->fs_info->super_lock);
        ret = btrfs_commit_transaction(trans, root);
 
@@ -394,13 +403,6 @@ static ssize_t btrfs_label_store(struct kobject *kobj,
 }
 BTRFS_ATTR_RW(label, 0644, btrfs_label_show, btrfs_label_store);
 
-static ssize_t btrfs_no_store(struct kobject *kobj,
-                                struct kobj_attribute *a,
-                                const char *buf, size_t len)
-{
-       return -EPERM;
-}
-
 static ssize_t btrfs_nodesize_show(struct kobject *kobj,
                                struct kobj_attribute *a, char *buf)
 {
@@ -409,7 +411,7 @@ static ssize_t btrfs_nodesize_show(struct kobject *kobj,
        return snprintf(buf, PAGE_SIZE, "%u\n", fs_info->super_copy->nodesize);
 }
 
-BTRFS_ATTR_RW(nodesize, 0444, btrfs_nodesize_show, btrfs_no_store);
+BTRFS_ATTR(nodesize, 0444, btrfs_nodesize_show);
 
 static ssize_t btrfs_sectorsize_show(struct kobject *kobj,
                                struct kobj_attribute *a, char *buf)
@@ -419,7 +421,7 @@ static ssize_t btrfs_sectorsize_show(struct kobject *kobj,
        return snprintf(buf, PAGE_SIZE, "%u\n", fs_info->super_copy->sectorsize);
 }
 
-BTRFS_ATTR_RW(sectorsize, 0444, btrfs_sectorsize_show, btrfs_no_store);
+BTRFS_ATTR(sectorsize, 0444, btrfs_sectorsize_show);
 
 static ssize_t btrfs_clone_alignment_show(struct kobject *kobj,
                                struct kobj_attribute *a, char *buf)
@@ -429,7 +431,7 @@ static ssize_t btrfs_clone_alignment_show(struct kobject *kobj,
        return snprintf(buf, PAGE_SIZE, "%u\n", fs_info->super_copy->sectorsize);
 }
 
-BTRFS_ATTR_RW(clone_alignment, 0444, btrfs_clone_alignment_show, btrfs_no_store);
+BTRFS_ATTR(clone_alignment, 0444, btrfs_clone_alignment_show);
 
 static struct attribute *btrfs_attrs[] = {
        BTRFS_ATTR_PTR(label),
@@ -614,7 +616,7 @@ int btrfs_kobj_rm_device(struct btrfs_fs_info *fs_info,
        if (!fs_info->device_dir_kobj)
                return -EINVAL;
 
-       if (one_device) {
+       if (one_device && one_device->bdev) {
                disk = one_device->bdev->bd_part;
                disk_kobj = &part_to_dev(disk)->kobj;