netfs: zero the tail of a short DIO/unbuffered readgrafted

The buffered read collector zero-fills the tail of a short read that
stops below the inode's i_size (netfs_clear_unread()), so a read that
races an extending write still returns the expected number of bytes.
The non-buffered collector path does no such thing: it just records
how much was transferred.

Add the same zero-fill for the non-buffered case, gated on
NETFS_SREQ_CLEAR_TAIL: a subreq's source sets that flag when a short
result from it is known to be safe to treat as a hole, as opposed to
NETFS_SREQ_HIT_EOF, which means the read genuinely ran off the end of
the file and should be reported short as-is. Only CLEAR_TAIL should
zero-fill here; a real EOF must stay a real short read.

No source currently sets CLEAR_TAIL on an unbuffered/DIO subrequest,
so this is inert on its own -- a following change teaches cifs to set
it in the one case that needs it.

Fixes: e2d46f2ec332 ("netfs: Change the read result collector to only use one work item")
Reviewed-by: David Howells <dhowells@redhat.com>
Reviewed-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Paulo Alcantara <pc@manguebit.org>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Ronnie Sahlberg <ronniesahlberg@gmail.com>
Cc: Shyam Prasad N <sprasad@microsoft.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: Bharath SM <bharathsm@microsoft.com>
Cc: stable@vger.kernel.org

1 files changed, 27 insertions, 0 deletions

diff --git a/drivers/of/Makefile b/drivers/of/Makefile
new file mode 100644
index 000000000..379a0afcb
--- /dev/null
+++ b/drivers/of/Makefile
@@ -0,0 +1,27 @@
+# SPDX-License-Identifier: GPL-2.0
+obj-y = base.o cpu.o device.o module.o platform.o property.o
+obj-$(CONFIG_OF_KOBJ) += kobj.o
+obj-$(CONFIG_OF_DYNAMIC) += dynamic.o
+obj-$(CONFIG_OF_FLATTREE) += fdt.o empty_root.dtb.o
+obj-$(CONFIG_OF_EARLY_FLATTREE) += fdt_address.o
+obj-$(CONFIG_OF_PROMTREE) += pdt.o
+obj-$(CONFIG_OF_ADDRESS)  += address.o
+obj-$(CONFIG_OF_IRQ)    += irq.o
+obj-$(CONFIG_OF_UNITTEST) += unittest.o
+obj-$(CONFIG_OF_RESERVED_MEM) += of_reserved_mem.o
+obj-$(CONFIG_OF_RESOLVE)  += resolver.o
+obj-$(CONFIG_OF_OVERLAY) += overlay.o
+obj-$(CONFIG_OF_NUMA) += of_numa.o
+
+ifdef CONFIG_KEXEC_FILE
+ifdef CONFIG_OF_FLATTREE
+obj-y	+= kexec.o
+endif
+endif
+
+obj-$(CONFIG_KUNIT) += of_kunit_helpers.o
+obj-$(CONFIG_OF_KUNIT_TEST) += of_test.o
+obj-$(CONFIG_OF_OVERLAY_KUNIT_TEST) += overlay-test.o
+overlay-test-y := overlay_test.o kunit_overlay_test.dtbo.o
+
+obj-$(CONFIG_OF_UNITTEST) += unittest-data/