cifs: Fix handling of a beyond-EOF DIO/unbuffered read over SMB2

Browse source

[ Upstream commit 4ae4dde6f3 ]

If a DIO read or an unbuffered read request extends beyond the EOF, the
server will return a short read and a status code indicating that EOF was
hit, which gets translated to -ENODATA.  Note that the client does not cap
the request at i_size, but asks for the amount requested in case there's a
race on the server with a third party.

Now, on the client side, the request will get split into multiple
subrequests if rsize is smaller than the full request size.  A subrequest
that starts before or at the EOF and returns short data up to the EOF will
be correctly handled, with the NETFS_SREQ_HIT_EOF flag being set,
indicating to netfslib that we can't read more.

If a subrequest, however, starts after the EOF and not at it, HIT_EOF will
not be flagged, its error will be set to -ENODATA and it will be abandoned.
This will cause the request as a whole to fail with -ENODATA.

Fix this by setting NETFS_SREQ_HIT_EOF on any subrequest that lies beyond
the EOF marker.

Fixes: 1da29f2c39 ("netfs, cifs: Fix handling of short DIO read")
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Paulo Alcantara (Red Hat) <pc@manguebit.org>
cc: Shyam Prasad N <sprasad@microsoft.com>
cc: linux-cifs@vger.kernel.org
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

...

This commit is contained in:

David Howells 2025-12-03 21:55:27 +00:00 • committed by Greg Kroah-Hartman

parent 7cd9ed8132

commit 341d5aa3f0

1 changed files with 1 additions and 1 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

2

fs/smb/client/smb2pdu.c

View file