Re: [PATCH] src/attr_replace_test: limit size of extended attribute value

[Luis Henriques <lhenriques@suse.com>]

Nikolay Borisov <nborisov@suse.com> writes:

> On 17.05.19 г. 15:06 ч., Luis Henriques wrote:
>> The maximum size for extended attribute values is 65536 (XATTR_SIZE_MAX).
>> Since there are filesystems that can set blksize to really big values
>> (CephFS for example has a default of 4M), it's easy to have this test
>> failing with fsetxattr returning -E2BIG.
>> 
>> Cc: Darrick J. Wong <darrick.wong@oracle.com>
>> Signed-off-by: Luis Henriques <lhenriques@suse.com>
>> ---
>>  src/attr_replace_test.c | 3 +++
>>  1 file changed, 3 insertions(+)
>> 
>> diff --git a/src/attr_replace_test.c b/src/attr_replace_test.c
>> index 0720bfdc18ab..1ca9bf11ba58 100644
>> --- a/src/attr_replace_test.c
>> +++ b/src/attr_replace_test.c
>> @@ -9,6 +9,7 @@
>>  #include <sys/types.h>
>>  #include <sys/xattr.h>
>>  #include <sys/stat.h>
>> +#include <linux/limits.h>
>>  
>>  #define die() do { perror(""); \
>>  fprintf(stderr, "error at line %d\n", __LINE__); \
>> @@ -44,6 +45,8 @@ int main(int argc, char *argv[])
>>  	size = sbuf.st_blksize * 3 / 4;
>>  	if (!size)
>>  		fail("Invalid st_blksize(%ld)\n", sbuf.st_blksize);
>> +	if (size > XATTR_SIZE_MAX)
>> +		size = XATTR_SIZE_MAX;
>
> nit: size = max(size, XATTRS_SIZE_MAX);

Thanks, Nikolay.  But I can't find the definition of such macro or
function.  I believe it's only available in kernel, right?  Also, you
probably meant min() ;-)

Cheers,
-- 
Luis