ext4: sysfs: print ext4_super_block fields as little-endian (a4d2aadc) · Commits · 戴 / test

While working on extended rand for last_error/first_error timestamps, I noticed that the endianess is wrong; we access the little-endian fields in struct ext4_super_block as native-endian when we print them. This adds a special case in ext4_attr_show() and ext4_attr_store() to byteswap the superblock fields if needed. In older kernels, this code was part of super.c, it got moved to sysfs.c in linux-4.4. Cc: stable@vger.kernel.org Fixes: ("ext4: add sysfs entry showing whether the fs contains errors") Reviewed-by:

Andreas Dilger <adilger@dilger.ca> Signed-off-by:

Arnd Bergmann <arnd@arndb.de> Signed-off-by:

Theodore Ts'o <tytso@mit.edu>

fs/ext4/sysfs.c

+10 −3

Original line number	Original line	Diff line number	Diff line
	@@ -274,6 +274,10 @@ static ssize_t ext4_attr_show(struct kobject *kobj,
	case attr_pointer_ui:		case attr_pointer_ui:
	if (!ptr)		if (!ptr)
	return 0;		return 0;
			if (a->attr_ptr == ptr_ext4_super_block_offset)
			return snprintf(buf, PAGE_SIZE, "%u\n",
			le32_to_cpup(ptr));
			else
	return snprintf(buf, PAGE_SIZE, "%u\n",		return snprintf(buf, PAGE_SIZE, "%u\n",
	((unsigned int ) ptr));		((unsigned int ) ptr));
	case attr_pointer_atomic:		case attr_pointer_atomic:
	@@ -308,6 +312,9 @@ static ssize_t ext4_attr_store(struct kobject *kobj,
	ret = kstrtoul(skip_spaces(buf), 0, &t);		ret = kstrtoul(skip_spaces(buf), 0, &t);
	if (ret)		if (ret)
	return ret;		return ret;
			if (a->attr_ptr == ptr_ext4_super_block_offset)
			((__le32 ) ptr) = cpu_to_le32(t);
			else
	((unsigned int ) ptr) = t;		((unsigned int ) ptr) = t;
	return len;		return len;
	case attr_inode_readahead:		case attr_inode_readahead:

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