Unverified Commit db26d62d authored by David Howells's avatar David Howells Committed by Christian Brauner
Browse files

netfs: Fix undifferentiation of DIO reads from unbuffered reads 



On cifs, "DIO reads" (specified by O_DIRECT) need to be differentiated from
"unbuffered reads" (specified by cache=none in the mount parameters).  The
difference is flagged in the protocol and the server may behave
differently: Windows Server will, for example, mandate that DIO reads are
block aligned.

Fix this by adding a NETFS_UNBUFFERED_READ to differentiate this from
NETFS_DIO_READ, parallelling the write differentiation that already exists.
cifs will then do the right thing.

Fixes: 016dc851 ("netfs: Implement unbuffered/DIO read support")
Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
Link: https://lore.kernel.org/3444961.1747987072@warthog.procyon.org.uk


Reviewed-by: default avatar"Paulo Alcantara (Red Hat)" <pc@manguebit.com>
Reviewed-by: default avatarViacheslav Dubeyko <Slava.Dubeyko@ibm.com>
cc: Steve French <sfrench@samba.org>
cc: netfs@lists.linux.dev
cc: v9fs@lists.linux.dev
cc: linux-afs@lists.infradead.org
cc: linux-cifs@vger.kernel.org
cc: ceph-devel@vger.kernel.org
cc: linux-nfs@vger.kernel.org
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parent 5fddfbc0

fs/9p/vfs_addr.c

+2 −1
Original line number Diff line number Diff line
@@ -77,7 +77,8 @@ static void v9fs_issue_read(struct netfs_io_subrequest *subreq) 


	/* if we just extended the file size, any portion not in

	 * cache won't be on server and is zeroes */

	if (subreq->rreq->origin != NETFS_DIO_READ)

	if (subreq->rreq->origin != NETFS_UNBUFFERED_READ &&

	    subreq->rreq->origin != NETFS_DIO_READ)

		__set_bit(NETFS_SREQ_CLEAR_TAIL, &subreq->flags);

	if (pos + total >= i_size_read(rreq->inode))

		__set_bit(NETFS_SREQ_HIT_EOF, &subreq->flags);

fs/afs/write.c

+1 −0
Original line number Diff line number Diff line
@@ -202,6 +202,7 @@ void afs_retry_request(struct netfs_io_request *wreq, struct netfs_io_stream *st 
	case NETFS_READ_GAPS:

	case NETFS_READ_SINGLE:

	case NETFS_READ_FOR_WRITE:

	case NETFS_UNBUFFERED_READ:

	case NETFS_DIO_READ:

		return;

	default:

fs/ceph/addr.c

+3 −1
Original line number Diff line number Diff line
@@ -238,6 +238,7 @@ static void finish_netfs_read(struct ceph_osd_request *req) 
		if (sparse && err > 0)

			err = ceph_sparse_ext_map_end(op);

		if (err < subreq->len &&

		    subreq->rreq->origin != NETFS_UNBUFFERED_READ &&

		    subreq->rreq->origin != NETFS_DIO_READ)

			__set_bit(NETFS_SREQ_CLEAR_TAIL, &subreq->flags);

		if (IS_ENCRYPTED(inode) && err > 0) {
@@ -281,7 +282,8 @@ static bool ceph_netfs_issue_op_inline(struct netfs_io_subrequest *subreq) 
	size_t len;

	int mode;



	if (rreq->origin != NETFS_DIO_READ)

	if (rreq->origin != NETFS_UNBUFFERED_READ &&

	    rreq->origin != NETFS_DIO_READ)

		__set_bit(NETFS_SREQ_CLEAR_TAIL, &subreq->flags);

	__clear_bit(NETFS_SREQ_COPY_TO_CACHE, &subreq->flags);

fs/netfs/direct_read.c

+2 −1
Original line number Diff line number Diff line
@@ -185,7 +185,8 @@ ssize_t netfs_unbuffered_read_iter_locked(struct kiocb *iocb, struct iov_iter *i 


	rreq = netfs_alloc_request(iocb->ki_filp->f_mapping, iocb->ki_filp,

				   iocb->ki_pos, orig_count,

				   NETFS_DIO_READ);

				   iocb->ki_flags & IOCB_DIRECT ?

				   NETFS_DIO_READ : NETFS_UNBUFFERED_READ);

	if (IS_ERR(rreq))

		return PTR_ERR(rreq);

fs/netfs/main.c

+1 −0
Original line number Diff line number Diff line
@@ -39,6 +39,7 @@ static const char *netfs_origins[nr__netfs_io_origin] = { 
	[NETFS_READ_GAPS]		= "RG",

	[NETFS_READ_SINGLE]		= "R1",

	[NETFS_READ_FOR_WRITE]		= "RW",

	[NETFS_UNBUFFERED_READ]		= "UR",

	[NETFS_DIO_READ]		= "DR",

	[NETFS_WRITEBACK]		= "WB",

	[NETFS_WRITEBACK_SINGLE]	= "W1",