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netfs: Fix undifferentiation of DIO reads from unbuffered reads

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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: 016dc8516a ("netfs: Implement unbuffered/DIO read support")
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://lore.kernel.org/3444961.1747987072@warthog.procyon.org.uk
Reviewed-by: "Paulo Alcantara (Red Hat)" <pc@manguebit.com>
Reviewed-by: Viacheslav 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: Christian Brauner <brauner@kernel.org>
This commit is contained in:
David Howells
2025-05-23 08:57:52 +01:00
committed by Christian Brauner
parent 5fddfbc0cb
commit db26d62d79
12 changed files with 21 additions and 6 deletions
Download Patch File Download Diff File Expand all files Collapse all files

3
fs/netfs/direct_read.c
View File

@@ -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);

1
fs/netfs/main.c
View File

@@ -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",

1
fs/netfs/misc.c
View File

@@ -461,6 +461,7 @@ all_collected:
case NETFS_DIO_READ:
case NETFS_DIO_WRITE:
case NETFS_READ_SINGLE:
case NETFS_UNBUFFERED_READ:
case NETFS_UNBUFFERED_WRITE:
break;
default:

1
fs/netfs/objects.c
View File

@@ -59,6 +59,7 @@ struct netfs_io_request *netfs_alloc_request(struct address_space *mapping,
origin == NETFS_READ_GAPS ||
origin == NETFS_READ_SINGLE ||
origin == NETFS_READ_FOR_WRITE ||
origin == NETFS_UNBUFFERED_READ ||
origin == NETFS_DIO_READ) {
INIT_WORK(&rreq->work, netfs_read_collection_worker);
rreq->io_streams[0].avail = true;

7
fs/netfs/read_collect.c
View File

@@ -340,7 +340,8 @@ static void netfs_rreq_assess_dio(struct netfs_io_request *rreq)
{
unsigned int i;
if (rreq->origin == NETFS_DIO_READ) {
if (rreq->origin == NETFS_UNBUFFERED_READ ||
rreq->origin == NETFS_DIO_READ) {
for (i = 0; i < rreq->direct_bv_count; i++) {
flush_dcache_page(rreq->direct_bv[i].bv_page);
// TODO: cifs marks pages in the destination buffer
@@ -358,7 +359,8 @@ static void netfs_rreq_assess_dio(struct netfs_io_request *rreq)
}
if (rreq->netfs_ops->done)
rreq->netfs_ops->done(rreq);
if (rreq->origin == NETFS_DIO_READ)
if (rreq->origin == NETFS_UNBUFFERED_READ ||
rreq->origin == NETFS_DIO_READ)
inode_dio_end(rreq->inode);
}
@@ -414,6 +416,7 @@ bool netfs_read_collection(struct netfs_io_request *rreq)
//netfs_rreq_is_still_valid(rreq);
switch (rreq->origin) {
case NETFS_UNBUFFERED_READ:
case NETFS_DIO_READ:
case NETFS_READ_GAPS:
netfs_rreq_assess_dio(rreq);