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, 41 insertions, 0 deletions

diff --git a/Documentation/process/conclave.rst b/Documentation/process/conclave.rst
new file mode 100644
index 000000000..6a1234f54
--- /dev/null
+++ b/Documentation/process/conclave.rst
@@ -0,0 +1,41 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+Linux kernel project continuity
+===============================
+
+The Linux kernel development project is widely distributed, with over
+100 maintainers each working to keep changes moving through their own
+repositories. The final step, though, is a centralized one where changes
+are pulled into the mainline repository. That is normally done by Linus
+Torvalds but, as was demonstrated by the 4.19 release in 2018, there are
+others who can do that work when the need arises.
+
+Should the maintainers of that repository become unwilling or unable to
+do that work going forward (including facilitating a transition), the
+project will need to find one or more replacements without delay. The
+process by which that will be done is listed below. $ORGANIZER is the
+last Maintainer Summit organizer or the current Linux Foundation (LF)
+Technical Advisory Board (TAB) Chair as a backup.
+
+- Within 72 hours, $ORGANIZER will open a discussion with the invitees
+  of the most recently concluded Maintainers Summit. A meeting of those
+  invitees and the TAB, either online or in-person, will be set as soon
+  as possible in a way that maximizes the number of people who can
+  participate.
+
+- If there has been no Maintainers Summit in the last 15 months, the set of
+  invitees for this meeting will be determined by the TAB.
+
+- The invitees to this meeting may bring in other maintainers as needed.
+
+- This meeting, chaired by $ORGANIZER, will consider options for the
+  ongoing management of the top-level kernel repository consistent with
+  the expectation that it maximizes the long term health of the project
+  and its community.
+
+- Within two weeks, a representative of this group will communicate to the
+  broader community, using the ksummit@lists.linux.dev mailing list, what
+  the next steps will be.
+
+The Linux Foundation, as guided by the TAB, will take the steps
+necessary to support and implement this plan.