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 --- lib/net_utils.c | 27 +++++++++++++++++++++++++++ 1 file changed, 27 insertions(+) create mode 100644 lib/net_utils.c (limited to 'lib/net_utils.c') diff --git a/lib/net_utils.c b/lib/net_utils.c new file mode 100644 index 000000000..215cda672 --- /dev/null +++ b/lib/net_utils.c @@ -0,0 +1,27 @@ +// SPDX-License-Identifier: GPL-2.0 +#include +#include +#include +#include +#include + +bool mac_pton(const char *s, u8 *mac) +{ + int i; + + if (strnlen(s, MAC_ADDR_STR_LEN) < MAC_ADDR_STR_LEN) + return false; + + /* Don't dirty result unless string is valid MAC. */ + for (i = 0; i < ETH_ALEN; i++) { + if (!isxdigit(s[i * 3]) || !isxdigit(s[i * 3 + 1])) + return false; + if (i != ETH_ALEN - 1 && s[i * 3 + 2] != ':') + return false; + } + for (i = 0; i < ETH_ALEN; i++) { + mac[i] = (hex_to_bin(s[i * 3]) << 4) | hex_to_bin(s[i * 3 + 1]); + } + return true; +} +EXPORT_SYMBOL(mac_pton); -- cgit v1.3.1