From acce32a51e6c32e0ad8f921f9af2226e6750bb51 Mon Sep 17 00:00:00 2001 From: Kent Overstreet Date: Wed, 10 Apr 2024 14:32:45 -0400 Subject: bcachefs: printbuf improvements - fix assorted (harmless) off-by-one errors - we were inconsistent on whether out->pos stays <= out->size on overflow; now it does, and printbuf.overflow exists to indicate if a printbuf has overflowed - factor out printbuf_advance_pos() - printbuf_nul_terminate_reserved(); use this to reduce the number of printbuf_make_room() calls Signed-off-by: Kent Overstreet --- fs/bcachefs/printbuf.c | 65 ++++++++++++++++++++++++-------------------------- fs/bcachefs/printbuf.h | 53 +++++++++++++++++++--------------------- 2 files changed, 55 insertions(+), 63 deletions(-) diff --git a/fs/bcachefs/printbuf.c b/fs/bcachefs/printbuf.c index b27d22925929..46ce63312a3f 100644 --- a/fs/bcachefs/printbuf.c +++ b/fs/bcachefs/printbuf.c @@ -17,28 +17,28 @@ static inline unsigned printbuf_linelen(struct printbuf *buf) int bch2_printbuf_make_room(struct printbuf *out, unsigned extra) { - unsigned new_size; - char *buf; - - if (!out->heap_allocated) - return 0; - /* Reserved space for terminating nul: */ extra += 1; - if (out->pos + extra < out->size) + if (out->pos + extra <= out->size) return 0; - new_size = roundup_pow_of_two(out->size + extra); + if (!out->heap_allocated) { + out->overflow = true; + return 0; + } + + unsigned new_size = roundup_pow_of_two(out->size + extra); /* * Note: output buffer must be freeable with kfree(), it's not required * that the user use printbuf_exit(). */ - buf = krealloc(out->buf, new_size, !out->atomic ? GFP_KERNEL : GFP_NOWAIT); + char *buf = krealloc(out->buf, new_size, !out->atomic ? GFP_KERNEL : GFP_NOWAIT); if (!buf) { out->allocation_failure = true; + out->overflow = true; return -ENOMEM; } @@ -47,6 +47,11 @@ int bch2_printbuf_make_room(struct printbuf *out, unsigned extra) return 0; } +static void printbuf_advance_pos(struct printbuf *out, unsigned len) +{ + out->pos += min(len, printbuf_remaining(out)); +} + void bch2_prt_vprintf(struct printbuf *out, const char *fmt, va_list args) { int len; @@ -55,14 +60,12 @@ void bch2_prt_vprintf(struct printbuf *out, const char *fmt, va_list args) va_list args2; va_copy(args2, args); - len = vsnprintf(out->buf + out->pos, printbuf_remaining(out), fmt, args2); + len = vsnprintf(out->buf + out->pos, printbuf_remaining_size(out), fmt, args2); va_end(args2); - } while (len + 1 >= printbuf_remaining(out) && - !bch2_printbuf_make_room(out, len + 1)); + } while (len > printbuf_remaining(out) && + !bch2_printbuf_make_room(out, len)); - len = min_t(size_t, len, - printbuf_remaining(out) ? printbuf_remaining(out) - 1 : 0); - out->pos += len; + printbuf_advance_pos(out, len); } void bch2_prt_printf(struct printbuf *out, const char *fmt, ...) @@ -72,14 +75,12 @@ void bch2_prt_printf(struct printbuf *out, const char *fmt, ...) do { va_start(args, fmt); - len = vsnprintf(out->buf + out->pos, printbuf_remaining(out), fmt, args); + len = vsnprintf(out->buf + out->pos, printbuf_remaining_size(out), fmt, args); va_end(args); - } while (len + 1 >= printbuf_remaining(out) && - !bch2_printbuf_make_room(out, len + 1)); + } while (len > printbuf_remaining(out) && + !bch2_printbuf_make_room(out, len)); - len = min_t(size_t, len, - printbuf_remaining(out) ? printbuf_remaining(out) - 1 : 0); - out->pos += len; + printbuf_advance_pos(out, len); } /** @@ -194,18 +195,15 @@ void bch2_printbuf_indent_sub(struct printbuf *buf, unsigned spaces) void bch2_prt_newline(struct printbuf *buf) { - unsigned i; - bch2_printbuf_make_room(buf, 1 + buf->indent); - __prt_char(buf, '\n'); + __prt_char_reserved(buf, '\n'); buf->last_newline = buf->pos; - for (i = 0; i < buf->indent; i++) - __prt_char(buf, ' '); + __prt_chars_reserved(buf, ' ', buf->indent); - printbuf_nul_terminate(buf); + printbuf_nul_terminate_reserved(buf); buf->last_field = buf->pos; buf->cur_tabstop = 0; @@ -262,7 +260,7 @@ static void __prt_tab_rjust(struct printbuf *buf) memset(buf->buf + buf->last_field, ' ', min((unsigned) pad, buf->size - buf->last_field)); - buf->pos += pad; + printbuf_advance_pos(buf, pad); printbuf_nul_terminate(buf); } @@ -348,9 +346,10 @@ void bch2_prt_bytes_indented(struct printbuf *out, const char *str, unsigned cou void bch2_prt_human_readable_u64(struct printbuf *out, u64 v) { bch2_printbuf_make_room(out, 10); - out->pos += string_get_size(v, 1, !out->si_units, - out->buf + out->pos, - printbuf_remaining_size(out)); + unsigned len = string_get_size(v, 1, !out->si_units, + out->buf + out->pos, + printbuf_remaining_size(out)); + printbuf_advance_pos(out, len); } /** @@ -402,9 +401,7 @@ void bch2_prt_string_option(struct printbuf *out, const char * const list[], size_t selected) { - size_t i; - - for (i = 0; list[i]; i++) + for (size_t i = 0; list[i]; i++) bch2_prt_printf(out, i == selected ? "[%s] " : "%s ", list[i]); } diff --git a/fs/bcachefs/printbuf.h b/fs/bcachefs/printbuf.h index 9a4a56c40937..9ecc56bc9635 100644 --- a/fs/bcachefs/printbuf.h +++ b/fs/bcachefs/printbuf.h @@ -86,6 +86,7 @@ struct printbuf { u8 atomic; bool allocation_failure:1; bool heap_allocated:1; + bool overflow:1; enum printbuf_si si_units:1; bool human_readable_units:1; bool has_indent_or_tabstops:1; @@ -142,7 +143,9 @@ void bch2_prt_bitflags_vector(struct printbuf *, const char * const[], */ static inline unsigned printbuf_remaining_size(struct printbuf *out) { - return out->pos < out->size ? out->size - out->pos : 0; + if (WARN_ON(out->size && out->pos >= out->size)) + out->pos = out->size - 1; + return out->size - out->pos; } /* @@ -151,7 +154,7 @@ static inline unsigned printbuf_remaining_size(struct printbuf *out) */ static inline unsigned printbuf_remaining(struct printbuf *out) { - return out->pos < out->size ? out->size - out->pos - 1 : 0; + return out->size ? printbuf_remaining_size(out) - 1 : 0; } static inline unsigned printbuf_written(struct printbuf *out) @@ -159,30 +162,25 @@ static inline unsigned printbuf_written(struct printbuf *out) return out->size ? min(out->pos, out->size - 1) : 0; } -/* - * Returns true if output was truncated: - */ -static inline bool printbuf_overflowed(struct printbuf *out) +static inline void printbuf_nul_terminate_reserved(struct printbuf *out) { - return out->pos >= out->size; + if (WARN_ON(out->size && out->pos >= out->size)) + out->pos = out->size - 1; + if (out->size) + out->buf[out->pos] = 0; } static inline void printbuf_nul_terminate(struct printbuf *out) { bch2_printbuf_make_room(out, 1); - - if (out->pos < out->size) - out->buf[out->pos] = 0; - else if (out->size) - out->buf[out->size - 1] = 0; + printbuf_nul_terminate_reserved(out); } /* Doesn't call bch2_printbuf_make_room(), doesn't nul terminate: */ static inline void __prt_char_reserved(struct printbuf *out, char c) { if (printbuf_remaining(out)) - out->buf[out->pos] = c; - out->pos++; + out->buf[out->pos++] = c; } /* Doesn't nul terminate: */ @@ -194,37 +192,34 @@ static inline void __prt_char(struct printbuf *out, char c) static inline void prt_char(struct printbuf *out, char c) { - __prt_char(out, c); - printbuf_nul_terminate(out); + bch2_printbuf_make_room(out, 2); + __prt_char_reserved(out, c); + printbuf_nul_terminate_reserved(out); } static inline void __prt_chars_reserved(struct printbuf *out, char c, unsigned n) { - unsigned i, can_print = min(n, printbuf_remaining(out)); + unsigned can_print = min(n, printbuf_remaining(out)); - for (i = 0; i < can_print; i++) + for (unsigned i = 0; i < can_print; i++) out->buf[out->pos++] = c; - out->pos += n - can_print; } static inline void prt_chars(struct printbuf *out, char c, unsigned n) { bch2_printbuf_make_room(out, n); __prt_chars_reserved(out, c, n); - printbuf_nul_terminate(out); + printbuf_nul_terminate_reserved(out); } static inline void prt_bytes(struct printbuf *out, const void *b, unsigned n) { - unsigned i, can_print; - bch2_printbuf_make_room(out, n); - can_print = min(n, printbuf_remaining(out)); + unsigned can_print = min(n, printbuf_remaining(out)); - for (i = 0; i < can_print; i++) + for (unsigned i = 0; i < can_print; i++) out->buf[out->pos++] = ((char *) b)[i]; - out->pos += n - can_print; printbuf_nul_terminate(out); } @@ -241,18 +236,18 @@ static inline void prt_str_indented(struct printbuf *out, const char *str) static inline void prt_hex_byte(struct printbuf *out, u8 byte) { - bch2_printbuf_make_room(out, 2); + bch2_printbuf_make_room(out, 3); __prt_char_reserved(out, hex_asc_hi(byte)); __prt_char_reserved(out, hex_asc_lo(byte)); - printbuf_nul_terminate(out); + printbuf_nul_terminate_reserved(out); } static inline void prt_hex_byte_upper(struct printbuf *out, u8 byte) { - bch2_printbuf_make_room(out, 2); + bch2_printbuf_make_room(out, 3); __prt_char_reserved(out, hex_asc_upper_hi(byte)); __prt_char_reserved(out, hex_asc_upper_lo(byte)); - printbuf_nul_terminate(out); + printbuf_nul_terminate_reserved(out); } /** -- cgit v1.2.3