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Registered in England and Wales under Company Registration No. 3798903 From: David Howells To: Paulo Alcantara cc: dhowells@redhat.com, Steve French , Christian Brauner , netfs@lists.linux.dev, v9fs@lists.linux.dev, linux-afs@lists.infradead.org, linux-cifs@vger.kernel.org, ceph-devel@vger.kernel.org, linux-nfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] netfs: Fix undifferentiation of DIO reads from unbuffered reads Precedence: bulk X-Mailing-List: ceph-devel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-ID: <3064918.1745444289.1@warthog.procyon.org.uk> Date: Wed, 23 Apr 2025 22:38:09 +0100 Message-ID: <3064919.1745444289@warthog.procyon.org.uk> X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.93 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. A further patch will be required to make cifs do something different, depending on the rreq->origin set. Fixes: 016dc8516aec ("netfs: Implement unbuffered/DIO read support") Signed-off-by: David Howells cc: Paulo Alcantara cc: Steve French 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 Reviewed-by: Paulo Alcantara (Red Hat) --- fs/9p/vfs_addr.c | 3 ++- fs/afs/write.c | 1 + fs/ceph/addr.c | 4 +++- fs/netfs/direct_read.c | 3 ++- fs/netfs/main.c | 1 + fs/netfs/misc.c | 1 + fs/netfs/objects.c | 1 + fs/netfs/read_collect.c | 7 +++++-- fs/nfs/fscache.c | 1 + fs/smb/client/file.c | 3 ++- include/linux/netfs.h | 1 + include/trace/events/netfs.h | 1 + 12 files changed, 21 insertions(+), 6 deletions(-) diff --git a/fs/9p/vfs_addr.c b/fs/9p/vfs_addr.c index b5a4a28e0fe7..e4420591cf35 100644 --- a/fs/9p/vfs_addr.c +++ b/fs/9p/vfs_addr.c @@ -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); diff --git a/fs/afs/write.c b/fs/afs/write.c index 7df7b2f5e7b2..2e7526ea883a 100644 --- a/fs/afs/write.c +++ b/fs/afs/write.c @@ -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: diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c index 557c326561fd..b95c4cb21c13 100644 --- a/fs/ceph/addr.c +++ b/fs/ceph/addr.c @@ -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); diff --git a/fs/netfs/direct_read.c b/fs/netfs/direct_read.c index a24e63d2c818..9902766195d7 100644 --- a/fs/netfs/direct_read.c +++ b/fs/netfs/direct_read.c @@ -188,7 +188,8 @@ 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); diff --git a/fs/netfs/main.c b/fs/netfs/main.c index 70ecc8f5f210..3db401d269e7 100644 --- a/fs/netfs/main.c +++ b/fs/netfs/main.c @@ -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", diff --git a/fs/netfs/misc.c b/fs/netfs/misc.c index 77e7f7c79d27..43b67a28a8fa 100644 --- a/fs/netfs/misc.c +++ b/fs/netfs/misc.c @@ -461,6 +461,7 @@ static ssize_t netfs_wait_for_request(struct netfs_io_request *rreq, case NETFS_DIO_READ: case NETFS_DIO_WRITE: case NETFS_READ_SINGLE: + case NETFS_UNBUFFERED_READ: case NETFS_UNBUFFERED_WRITE: break; default: diff --git a/fs/netfs/objects.c b/fs/netfs/objects.c index d3eb9ba3013a..31fa0c81e2a4 100644 --- a/fs/netfs/objects.c +++ b/fs/netfs/objects.c @@ -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; diff --git a/fs/netfs/read_collect.c b/fs/netfs/read_collect.c index 900dd51c3b94..bad677e58a42 100644 --- a/fs/netfs/read_collect.c +++ b/fs/netfs/read_collect.c @@ -342,7 +342,8 @@ 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 @@ -360,7 +361,8 @@ 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); } @@ -416,6 +418,7 @@ 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); diff --git a/fs/nfs/fscache.c b/fs/nfs/fscache.c index e278a1ad1ca3..8b0785178731 100644 --- a/fs/nfs/fscache.c +++ b/fs/nfs/fscache.c @@ -367,6 +367,7 @@ void nfs_netfs_read_completion(struct nfs_pgio_header *hdr) sreq = netfs->sreq; if (test_bit(NFS_IOHDR_EOF, &hdr->flags) && + sreq->rreq->origin != NETFS_UNBUFFERED_READ && sreq->rreq->origin != NETFS_DIO_READ) __set_bit(NETFS_SREQ_CLEAR_TAIL, &sreq->flags); diff --git a/fs/smb/client/file.c b/fs/smb/client/file.c index 3bd34d2b98d0..76f91ce6b29b 100644 --- a/fs/smb/client/file.c +++ b/fs/smb/client/file.c @@ -219,7 +219,8 @@ static void cifs_issue_read(struct netfs_io_subrequest *subreq) goto failed; } - 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); trace_netfs_sreq(subreq, netfs_sreq_trace_submit); diff --git a/include/linux/netfs.h b/include/linux/netfs.h index c3f230732f51..1464b3a10498 100644 --- a/include/linux/netfs.h +++ b/include/linux/netfs.h @@ -206,6 +206,7 @@ enum netfs_io_origin { NETFS_READ_GAPS, /* This read is a synchronous read to fill gaps */ NETFS_READ_SINGLE, /* This read should be treated as a single object */ NETFS_READ_FOR_WRITE, /* This read is to prepare a write */ + NETFS_UNBUFFERED_READ, /* This is an unbuffered read */ NETFS_DIO_READ, /* This is a direct I/O read */ NETFS_WRITEBACK, /* This write was triggered by writepages */ NETFS_WRITEBACK_SINGLE, /* This monolithic write was triggered by writepages */ diff --git a/include/trace/events/netfs.h b/include/trace/events/netfs.h index 402c5e82e7b8..4175eec40048 100644 --- a/include/trace/events/netfs.h +++ b/include/trace/events/netfs.h @@ -39,6 +39,7 @@ EM(NETFS_READ_GAPS, "RG") \ EM(NETFS_READ_SINGLE, "R1") \ EM(NETFS_READ_FOR_WRITE, "RW") \ + EM(NETFS_UNBUFFERED_READ, "UR") \ EM(NETFS_DIO_READ, "DR") \ EM(NETFS_WRITEBACK, "WB") \ EM(NETFS_WRITEBACK_SINGLE, "W1") \