"Jeff Layton" <jlayton@xxxxxxxxxx> writes:
> On Mon, 2019-07-01 at 18:16 +0100, Luis Henriques wrote:
>> Commit e450f4d1a5d6 ("ceph: pass inclusive lend parameter to
>> filemap_write_and_wait_range()") fixed the end offset parameter used to
>> call filemap_write_and_wait_range and invalidate_inode_pages2_range.
>> Unfortunately it missed truncate_inode_pages_range, introducing a
>> regression that is easily detected by xfstest generic/130.
>>
>> The problem is that when doing direct IO it is possible that an extra page
>> is truncated from the page cache when the end offset is page aligned.
>> This can cause data loss if that page hasn't been sync'ed to the OSDs.
>>
>> While there, change code to use PAGE_ALIGN macro instead.
>>
>> Fixes: e450f4d1a5d6 ("ceph: pass inclusive lend parameter to filemap_write_and_wait_range()")
>> Signed-off-by: Luis Henriques <lhenriques@xxxxxxxx>
>> ---
>> fs/ceph/file.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/fs/ceph/file.c b/fs/ceph/file.c
>> index 183c37c0a8fc..7a57db8e2fa9 100644
>> --- a/fs/ceph/file.c
>> +++ b/fs/ceph/file.c
>> @@ -1007,7 +1007,7 @@ ceph_direct_read_write(struct kiocb *iocb, struct iov_iter *iter,
>> * may block.
>> */
>> truncate_inode_pages_range(inode->i_mapping, pos,
>> - (pos+len) | (PAGE_SIZE - 1));
>> + PAGE_ALIGN(pos + len) - 1);
>>
>> req->r_mtime = mtime;
>> }
>
> Luis, should this be sent to stable? It seems like a data corruption
> problem...
Yes, I believe so. But I believe all the active stable kernels that
include commit e450f4d1a5d6 (or a backport of it) will pick it anyway
due to the 'Fixes:' tag. AFAIK only 5.1 and 5.2 are affected.
Cheers,
--
Luis
