ACK: [PATCH][SRU][UTOPIC] btrfs: label should not contain return char

[Stefan Bader]

On 20.03.2015 13:29, Colin King wrote:
> From: Satoru Takeuchi <takeuchi_satoru at jp.fujitsu.com>
> 
> BugLink: http://bugs.launchpad.net/bugs/1434528
> 
> 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 at jp.fujitsu.com>
> Signed-off-by: Chris Mason <clm at fb.com>
> (cherry pick from upstream commit 48fcc3ff7dce0138c053833adf81670494f177f3)
> Signed-off-by: Colin Ian King <colin.king at canonical.com>
> ---
>  fs/btrfs/sysfs.c | 15 ++++++++++++---
>  1 file changed, 12 insertions(+), 3 deletions(-)
> 
> 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 @@ 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);
>  
> 


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