On 5/24/18 2:47 PM, Theodore Y. Ts'o wrote: > On Thu, May 24, 2018 at 10:02:54AM -0600, Jens Axboe wrote: >> a_ops->readpages() is only ever used for read-ahead. Ensure that we >> pass this information down to the block layer. >> >> Signed-off-by: Jens Axboe <axboe@xxxxxxxxx> >> --- >> fs/ext4/readpage.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/fs/ext4/readpage.c b/fs/ext4/readpage.c >> index 9ffa6fad18db..92b28273b223 100644 >> --- a/fs/ext4/readpage.c >> +++ b/fs/ext4/readpage.c >> @@ -259,7 +259,7 @@ int ext4_mpage_readpages(struct address_space *mapping, >> bio->bi_iter.bi_sector = blocks[0] << (blkbits - 9); >> bio->bi_end_io = mpage_end_io; >> bio->bi_private = ctx; >> - bio_set_op_attrs(bio, REQ_OP_READ, 0); >> + bio_set_op_attrs(bio, REQ_OP_READ, REQ_RAHEAD); >> } > > The problem is that ext4_readpage() also calls ext4_mpage_readpages(). > So you can't set REQ_RAHEAD unconditionally here. Oh shoot, yeah I did miss that. I'll update it, thanks Ted. -- Jens Axboe
