btrfs: label should not contain return char
Rediffed remaining parts of original patch from Anand Jain. This makes
sure to avoid trailing newlines in the btrfs label output
reproducer.sh:
===============================================================================
TEST_DEV=/dev/vdb
TEST_DIR=/home/sat/mnt
umount /home/sat/mnt
mkfs.btrfs -f $TEST_DEV
UUID=$(btrfs fi show $TEST_DEV | head -1 | sed -e 's/.*uuid: \([-0-9a-z]*\)$/\1/')
mount $TEST_DEV $TEST_DIR
LABELFILE=/sys/fs/btrfs/$UUID/label
echo "Test for empty label..." >&2
LINES="$(cat $LABELFILE | wc -l | awk '{print $1}')"
RET=0
if [ $LINES -eq 0 ] ; then
echo '[PASS] Trailing \n is removed correctly.' >&2
else
echo '[FAIL] Trailing \n still exists.' >&2
RET=1
fi
echo "Test for non-empty label..." >&2
echo testlabel >$LABELFILE
LINES="$(cat $LABELFILE | wc -l | awk '{print $1}')"
if [ $LINES -eq 1 ] ; then
echo '[PASS] Trailing \n is removed correctly.' >&2
else
echo '[FAIL] Trailing \n still exists.' >&2
RET=1
fi
exit $RET
===============================================================================
Signed-off-by: Satoru Takeuchi <takeuchi_satoru@jp.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
diff --git a/fs/btrfs/sysfs.c b/fs/btrfs/sysfs.c
index 12e5355..82a968f 100644
--- a/fs/btrfs/sysfs.c
+++ b/fs/btrfs/sysfs.c
@@ -363,7 +363,8 @@
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 @@
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 @@
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);