From dd05add7b2b6004c5fa3a1f276f56d8668f86b65 Mon Sep 17 00:00:00 2001 From: Paulo Alcantara Date: Sat, 26 Sep 2026 19:20:30 -0300 Subject: netfs: zero the tail of a short DIO/unbuffered read 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 Reviewed-by: Namjae Jeon Signed-off-by: Paulo Alcantara Cc: Christian Brauner Cc: Matthew Wilcox Cc: Ronnie Sahlberg Cc: Shyam Prasad N Cc: Tom Talpey Cc: Bharath SM Cc: stable@vger.kernel.org --- drivers/md/dm-vdo/string-utils.h | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+) create mode 100644 drivers/md/dm-vdo/string-utils.h (limited to 'drivers/md/dm-vdo/string-utils.h') diff --git a/drivers/md/dm-vdo/string-utils.h b/drivers/md/dm-vdo/string-utils.h new file mode 100644 index 000000000..96eecd38b --- /dev/null +++ b/drivers/md/dm-vdo/string-utils.h @@ -0,0 +1,23 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Copyright 2023 Red Hat + */ + +#ifndef VDO_STRING_UTILS_H +#define VDO_STRING_UTILS_H + +#include +#include + +/* Utilities related to string manipulation */ + +static inline const char *vdo_bool_to_string(bool value) +{ + return value ? "true" : "false"; +} + +/* Append a formatted string to the end of a buffer. */ +char *vdo_append_to_buffer(char *buffer, char *buf_end, const char *fmt, ...) + __printf(3, 4); + +#endif /* VDO_STRING_UTILS_H */ -- cgit v1.3.1