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 --- include/net/strparser.h | 170 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 170 insertions(+) create mode 100644 include/net/strparser.h (limited to 'include/net/strparser.h') diff --git a/include/net/strparser.h b/include/net/strparser.h new file mode 100644 index 000000000..0ed73e364 --- /dev/null +++ b/include/net/strparser.h @@ -0,0 +1,170 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Stream Parser + * + * Copyright (c) 2016 Tom Herbert + */ + +#ifndef __NET_STRPARSER_H_ +#define __NET_STRPARSER_H_ + +#include +#include + +#define STRP_STATS_ADD(stat, count) ((stat) += (count)) +#define STRP_STATS_INCR(stat) ((stat)++) + +struct strp_stats { + unsigned long long msgs; + unsigned long long bytes; + unsigned int mem_fail; + unsigned int need_more_hdr; + unsigned int msg_too_big; + unsigned int msg_timeouts; + unsigned int bad_hdr_len; +}; + +struct strp_aggr_stats { + unsigned long long msgs; + unsigned long long bytes; + unsigned int mem_fail; + unsigned int need_more_hdr; + unsigned int msg_too_big; + unsigned int msg_timeouts; + unsigned int bad_hdr_len; + unsigned int aborts; + unsigned int interrupted; + unsigned int unrecov_intr; +}; + +struct strparser; + +/* Callbacks are called with lock held for the attached socket */ +struct strp_callbacks { + int (*parse_msg)(struct strparser *strp, struct sk_buff *skb); + void (*rcv_msg)(struct strparser *strp, struct sk_buff *skb); + int (*read_sock)(struct strparser *strp, read_descriptor_t *desc, + sk_read_actor_t recv_actor); + int (*read_sock_done)(struct strparser *strp, int err); + void (*abort_parser)(struct strparser *strp, int err); + void (*lock)(struct strparser *strp); + void (*unlock)(struct strparser *strp); +}; + +struct strp_msg { + int full_len; + int offset; +}; + +struct _strp_msg { + /* Internal cb structure. struct strp_msg must be first for passing + * to upper layer. + */ + struct strp_msg strp; + int accum_len; +}; + +struct sk_skb_cb { +#define SK_SKB_CB_PRIV_LEN 20 + unsigned char data[SK_SKB_CB_PRIV_LEN]; + /* align strp on cache line boundary within skb->cb[] */ + unsigned char pad[4]; + struct _strp_msg strp; + + /* strp users' data follows */ + struct tls_msg { + u8 control; + } tls; + /* temp_reg is a temporary register used for bpf_convert_data_end_access + * when dst_reg == src_reg. + */ + u64 temp_reg; +}; + +static inline struct strp_msg *strp_msg(struct sk_buff *skb) +{ + return (struct strp_msg *)((void *)skb->cb + + offsetof(struct sk_skb_cb, strp)); +} + +/* Structure for an attached lower socket */ +struct strparser { + struct sock *sk; + + u32 stopped : 1; + u32 paused : 1; + u32 aborted : 1; + u32 interrupted : 1; + u32 unrecov_intr : 1; + + struct sk_buff **skb_nextp; + struct sk_buff *skb_head; + unsigned int need_bytes; + struct delayed_work msg_timer_work; + struct work_struct work; + struct strp_stats stats; + struct strp_callbacks cb; +}; + +/* Must be called with lock held for attached socket */ +static inline void strp_pause(struct strparser *strp) +{ + strp->paused = 1; +} + +/* May be called without holding lock for attached socket */ +void strp_unpause(struct strparser *strp); + +static inline void save_strp_stats(struct strparser *strp, + struct strp_aggr_stats *agg_stats) +{ + /* Save psock statistics in the mux when psock is being unattached. */ + +#define SAVE_PSOCK_STATS(_stat) (agg_stats->_stat += \ + strp->stats._stat) + SAVE_PSOCK_STATS(msgs); + SAVE_PSOCK_STATS(bytes); + SAVE_PSOCK_STATS(mem_fail); + SAVE_PSOCK_STATS(need_more_hdr); + SAVE_PSOCK_STATS(msg_too_big); + SAVE_PSOCK_STATS(msg_timeouts); + SAVE_PSOCK_STATS(bad_hdr_len); +#undef SAVE_PSOCK_STATS + + if (strp->aborted) + agg_stats->aborts++; + if (strp->interrupted) + agg_stats->interrupted++; + if (strp->unrecov_intr) + agg_stats->unrecov_intr++; +} + +static inline void aggregate_strp_stats(struct strp_aggr_stats *stats, + struct strp_aggr_stats *agg_stats) +{ +#define SAVE_PSOCK_STATS(_stat) (agg_stats->_stat += stats->_stat) + SAVE_PSOCK_STATS(msgs); + SAVE_PSOCK_STATS(bytes); + SAVE_PSOCK_STATS(mem_fail); + SAVE_PSOCK_STATS(need_more_hdr); + SAVE_PSOCK_STATS(msg_too_big); + SAVE_PSOCK_STATS(msg_timeouts); + SAVE_PSOCK_STATS(bad_hdr_len); + SAVE_PSOCK_STATS(aborts); + SAVE_PSOCK_STATS(interrupted); + SAVE_PSOCK_STATS(unrecov_intr); +#undef SAVE_PSOCK_STATS + +} + +void strp_done(struct strparser *strp); +void strp_stop(struct strparser *strp); +void strp_check_rcv(struct strparser *strp); +int strp_init(struct strparser *strp, struct sock *sk, + const struct strp_callbacks *cb); +void strp_data_ready(struct strparser *strp); +int strp_process(struct strparser *strp, struct sk_buff *orig_skb, + unsigned int orig_offset, size_t orig_len, + size_t max_msg_size, long timeo); + +#endif /* __NET_STRPARSER_H_ */ -- cgit v1.3.1