sys-utils/fallocate.c

   1 /*
   2  * fallocate - utility to use the fallocate system call
   3  *
   4  * Copyright (C) 2008-2009 Red Hat, Inc. All rights reserved.
   5  * Written by Eric Sandeen <sandeen@redhat.com>
   6  *            Karel Zak <kzak@redhat.com>
   7  *
   8  * cvtnum routine taken from xfsprogs,
   9  * Copyright (c) 2003-2005 Silicon Graphics, Inc.
  10  *
  11  * This program is free software; you can redistribute it and/or
  12  * modify it under the terms of the GNU General Public License as
  13  * published by the Free Software Foundation.
  14  *
  15  * This program is distributed in the hope that it would be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  * GNU General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License along
  21  * with this program; if not, write to the Free Software Foundation, Inc.,
  22  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  23  */
  24 #include <sys/stat.h>
  25 #include <sys/types.h>
  26 #include <sys/mman.h>
  27 #include <ctype.h>
  28 #include <errno.h>
  29 #include <fcntl.h>
  30 #include <stdio.h>
  31 #include <stdlib.h>
  32 #include <unistd.h>
  33 #include <getopt.h>
  34 #include <limits.h>
  35 #include <string.h>
  36
  37 #ifndef HAVE_FALLOCATE
  38 # include <sys/syscall.h>
  39 #endif
  40
  41 #if defined(HAVE_LINUX_FALLOC_H) && \
  42     (!defined(FALLOC_FL_KEEP_SIZE) || !defined(FALLOC_FL_PUNCH_HOLE) || \
  43      !defined(FALLOC_FL_COLLAPSE_RANGE) || !defined(FALLOC_FL_ZERO_RANGE) || \
  44      !defined(FALLOC_FL_INSERT_RANGE))
  45 # include <linux/falloc.h>      /* non-libc fallback for FALLOC_FL_* flags */
  46 #endif
  47
  48
  49 #ifndef FALLOC_FL_KEEP_SIZE
  50 # define FALLOC_FL_KEEP_SIZE            0x1
  51 #endif
  52
  53 #ifndef FALLOC_FL_PUNCH_HOLE
  54 # define FALLOC_FL_PUNCH_HOLE           0x2
  55 #endif
  56
  57 #ifndef FALLOC_FL_COLLAPSE_RANGE
  58 # define FALLOC_FL_COLLAPSE_RANGE       0x8
  59 #endif
  60
  61 #ifndef FALLOC_FL_ZERO_RANGE
  62 # define FALLOC_FL_ZERO_RANGE           0x10
  63 #endif
  64
  65 #ifndef FALLOC_FL_INSERT_RANGE
  66 # define FALLOC_FL_INSERT_RANGE         0x20
  67 #endif
  68
  69 #include "nls.h"
  70 #include "strutils.h"
  71 #include "c.h"
  72 #include "closestream.h"
  73 #include "xalloc.h"
  74 #include "optutils.h"
  75
  76 static int verbose;
  77 static char *filename;
  78
  79 static void __attribute__((__noreturn__)) usage(void)
  80 {
  81         FILE *out = stdout;
  82         fputs(USAGE_HEADER, out);
  83         fprintf(out,
  84               _(" %s [options] <filename>\n"), program_invocation_short_name);
  85
  86         fputs(USAGE_SEPARATOR, out);
  87         fputs(_("Preallocate space to, or deallocate space from a file.\n"), out);
  88
  89         fputs(USAGE_OPTIONS, out);
  90         fputs(_(" -c, --collapse-range remove a range from the file\n"), out);
  91         fputs(_(" -d, --dig-holes      detect zeroes and replace with holes\n"), out);
  92         fputs(_(" -i, --insert-range   insert a hole at range, shifting existing data\n"), out);
  93         fputs(_(" -l, --length <num>   length for range operations, in bytes\n"), out);
  94         fputs(_(" -n, --keep-size      maintain the apparent size of the file\n"), out);
  95         fputs(_(" -o, --offset <num>   offset for range operations, in bytes\n"), out);
  96         fputs(_(" -p, --punch-hole     replace a range with a hole (implies -n)\n"), out);
  97         fputs(_(" -z, --zero-range     zero and ensure allocation of a range\n"), out);
  98 #ifdef HAVE_POSIX_FALLOCATE
  99         fputs(_(" -x, --posix          use posix_fallocate(3) instead of fallocate(2)\n"), out);
 100 #endif
 101         fputs(_(" -v, --verbose        verbose mode\n"), out);
 102
 103         fputs(USAGE_SEPARATOR, out);
 104         fprintf(out, USAGE_HELP_OPTIONS(22));
 105
 106         fputs(USAGE_ARGUMENTS, out);
 107         fprintf(out, USAGE_ARG_SIZE(_("<num>")));
 108
 109         fprintf(out, USAGE_MAN_TAIL("fallocate(1)"));
 110
 111         exit(EXIT_SUCCESS);
 112 }
 113
 114 static loff_t cvtnum(char *s)
 115 {
 116         uintmax_t x;
 117
 118         if (strtosize(s, &x))
 119                 return -1LL;
 120
 121         return x;
 122 }
 123
 124 static void xfallocate(int fd, int mode, off_t offset, off_t length)
 125 {
 126         int error;
 127
 128 #ifdef HAVE_FALLOCATE
 129         error = fallocate(fd, mode, offset, length);
 130 #else
 131         error = syscall(SYS_fallocate, fd, mode, offset, length);
 132 #endif
 133         /*
 134          * EOPNOTSUPP: The FALLOC_FL_KEEP_SIZE is unsupported
 135          * ENOSYS: The filesystem does not support sys_fallocate
 136          */
 137         if (error < 0) {
 138                 if ((mode & FALLOC_FL_KEEP_SIZE) && errno == EOPNOTSUPP)
 139                         errx(EXIT_FAILURE, _("fallocate failed: keep size mode is unsupported"));
 140                 err(EXIT_FAILURE, _("fallocate failed"));
 141         }
 142 }
 143
 144 #ifdef HAVE_POSIX_FALLOCATE
 145 static void xposix_fallocate(int fd, off_t offset, off_t length)
 146 {
 147         errno = posix_fallocate(fd, offset, length);
 148         if (errno != 0) {
 149                 err(EXIT_FAILURE, _("fallocate failed"));
 150         }
 151 }
 152 #endif
 153
 154 /* The real buffer size has to be bufsize + sizeof(uintptr_t) */
 155 static int is_nul(void *buf, size_t bufsize)
 156 {
 157         typedef uintptr_t word;
 158         void const *vp;
 159         char const *cbuf = buf, *cp;
 160         word const *wp = buf;
 161
 162         /* set sentinel */
 163         memset((char *) buf + bufsize, '\1', sizeof(word));
 164
 165         /* Find first nonzero *word*, or the word with the sentinel.  */
 166         while (*wp++ == 0)
 167                 continue;
 168
 169         /* Find the first nonzero *byte*, or the sentinel.  */
 170         vp = wp - 1;
 171         cp = vp;
 172
 173         while (*cp++ == 0)
 174                 continue;
 175
 176         return cbuf + bufsize < cp;
 177 }
 178
 179 static void dig_holes(int fd, off_t file_off, off_t len)
 180 {
 181         off_t file_end = len ? file_off + len : 0;
 182         off_t hole_start = 0, hole_sz = 0;
 183         uintmax_t ct = 0;
 184         size_t  bufsz;
 185         char *buf;
 186         struct stat st;
 187 #if defined(POSIX_FADV_SEQUENTIAL) && defined(HAVE_POSIX_FADVISE)
 188         off_t cache_start = file_off;
 189         /*
 190          * We don't want to call POSIX_FADV_DONTNEED to discard cached
 191          * data in PAGE_SIZE steps. IMHO it's overkill (too many syscalls).
 192          *
 193          * Let's assume that 1MiB (on system with 4K page size) is just
 194          * a good compromise.
 195          *                                          -- kzak Feb-2014
 196          */
 197         const size_t cachesz = getpagesize() * 256;
 198 #endif
 199
 200         if (fstat(fd, &st) != 0)
 201                 err(EXIT_FAILURE, _("stat of %s failed"), filename);
 202
 203         bufsz = st.st_blksize;
 204
 205         if (lseek(fd, file_off, SEEK_SET) < 0)
 206                 err(EXIT_FAILURE, _("seek on %s failed"), filename);
 207
 208         /* buffer + extra space for is_nul() sentinel */
 209         buf = xmalloc(bufsz + sizeof(uintptr_t));
 210         while (file_end == 0 || file_off < file_end) {
 211                 /*
 212                  * Detect data area (skip holes)
 213                  */
 214                 off_t end, off;
 215
 216                 off = lseek(fd, file_off, SEEK_DATA);
 217                 if ((off == -1 && errno == ENXIO) ||
 218                     (file_end && off >= file_end))
 219                         break;
 220
 221                 end = lseek(fd, off, SEEK_HOLE);
 222                 if (file_end && end > file_end)
 223                         end = file_end;
 224
 225                 if (off < 0 || end < 0)
 226                         break;
 227
 228 #if defined(POSIX_FADV_SEQUENTIAL) && defined(HAVE_POSIX_FADVISE)
 229                 (void) posix_fadvise(fd, off, end, POSIX_FADV_SEQUENTIAL);
 230 #endif
 231                 /*
 232                  * Dig holes in the area
 233                  */
 234                 while (off < end) {
 235                         ssize_t rsz = pread(fd, buf, bufsz, off);
 236                         if (rsz < 0 && errno)
 237                                 err(EXIT_FAILURE, _("%s: read failed"), filename);
 238                         if (end && rsz > 0 && off > end - rsz)
 239                                 rsz = end - off;
 240                         if (rsz <= 0)
 241                                 break;
 242
 243                         if (is_nul(buf, rsz)) {
 244                                 if (!hole_sz)                           /* new hole detected */
 245                                         hole_start = off;
 246                                 hole_sz += rsz;
 247                          } else if (hole_sz) {
 248                                 xfallocate(fd, FALLOC_FL_PUNCH_HOLE|FALLOC_FL_KEEP_SIZE,
 249                                            hole_start, hole_sz);
 250                                 ct += hole_sz;
 251                                 hole_sz = hole_start = 0;
 252                         }
 253
 254 #if defined(POSIX_FADV_DONTNEED) && defined(HAVE_POSIX_FADVISE)
 255                         /* discard cached data */
 256                         if (off - cache_start > (off_t) cachesz) {
 257                                 size_t clen = off - cache_start;
 258
 259                                 clen = (clen / cachesz) * cachesz;
 260                                 (void) posix_fadvise(fd, cache_start, clen, POSIX_FADV_DONTNEED);
 261                                 cache_start = cache_start + clen;
 262                         }
 263 #endif
 264                         off += rsz;
 265                 }
 266                 if (hole_sz) {
 267                         off_t alloc_sz = hole_sz;
 268                         if (off >= end)
 269                                 alloc_sz += st.st_blksize;              /* meet block boundary */
 270                         xfallocate(fd, FALLOC_FL_PUNCH_HOLE|FALLOC_FL_KEEP_SIZE,
 271                                         hole_start, alloc_sz);
 272                         ct += hole_sz;
 273                 }
 274                 file_off = off;
 275         }
 276
 277         free(buf);
 278
 279         if (verbose) {
 280                 char *str = size_to_human_string(SIZE_SUFFIX_3LETTER | SIZE_SUFFIX_SPACE, ct);
 281                 fprintf(stdout, _("%s: %s (%ju bytes) converted to sparse holes.\n"),
 282                                 filename, str, ct);
 283                 free(str);
 284         }
 285 }
 286
 287 int main(int argc, char **argv)
 288 {
 289         int     c;
 290         int     fd;
 291         int     mode = 0;
 292         int     dig = 0;
 293 #ifdef HAVE_POSIX_FALLOCATE
 294         int     posix = 0;
 295 #endif
 296         loff_t  length = -2LL;
 297         loff_t  offset = 0;
 298
 299         static const struct option longopts[] = {
 300             { "help",           no_argument,       NULL, 'h' },
 301             { "version",        no_argument,       NULL, 'V' },
 302             { "keep-size",      no_argument,       NULL, 'n' },
 303             { "punch-hole",     no_argument,       NULL, 'p' },
 304             { "collapse-range", no_argument,       NULL, 'c' },
 305             { "dig-holes",      no_argument,       NULL, 'd' },
 306             { "insert-range",   no_argument,       NULL, 'i' },
 307             { "zero-range",     no_argument,       NULL, 'z' },
 308             { "offset",         required_argument, NULL, 'o' },
 309             { "length",         required_argument, NULL, 'l' },
 310             { "posix",          no_argument,       NULL, 'x' },
 311             { "verbose",        no_argument,       NULL, 'v' },
 312             { NULL, 0, NULL, 0 }
 313         };
 314
 315         static const ul_excl_t excl[] = {       /* rows and cols in ASCII order */
 316                 { 'c', 'd', 'p', 'z' },
 317                 { 'c', 'n' },
 318                 { 'x', 'c', 'd', 'i', 'n', 'p', 'z'},
 319                 { 0 }
 320         };
 321         int excl_st[ARRAY_SIZE(excl)] = UL_EXCL_STATUS_INIT;
 322
 323         setlocale(LC_ALL, "");
 324         bindtextdomain(PACKAGE, LOCALEDIR);
 325         textdomain(PACKAGE);
 326         close_stdout_atexit();
 327
 328         while ((c = getopt_long(argc, argv, "hvVncpdizxl:o:", longopts, NULL))
 329                         != -1) {
 330
 331                 err_exclusive_options(c, longopts, excl, excl_st);
 332
 333                 switch(c) {
 334                 case 'c':
 335                         mode |= FALLOC_FL_COLLAPSE_RANGE;
 336                         break;
 337                 case 'd':
 338                         dig = 1;
 339                         break;
 340                 case 'i':
 341                         mode |= FALLOC_FL_INSERT_RANGE;
 342                         break;
 343                 case 'l':
 344                         length = cvtnum(optarg);
 345                         break;
 346                 case 'n':
 347                         mode |= FALLOC_FL_KEEP_SIZE;
 348                         break;
 349                 case 'o':
 350                         offset = cvtnum(optarg);
 351                         break;
 352                 case 'p':
 353                         mode |= FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE;
 354                         break;
 355                 case 'z':
 356                         mode |= FALLOC_FL_ZERO_RANGE;
 357                         break;
 358                 case 'x':
 359 #ifdef HAVE_POSIX_FALLOCATE
 360                         posix = 1;
 361                         break;
 362 #else
 363                         errx(EXIT_FAILURE, _("posix_fallocate support is not compiled"));
 364 #endif
 365                 case 'v':
 366                         verbose++;
 367                         break;
 368
 369                 case 'h':
 370                         usage();
 371                 case 'V':
 372                         print_version(EXIT_SUCCESS);
 373                 default:
 374                         errtryhelp(EXIT_FAILURE);
 375                 }
 376         }
 377
 378         if (optind == argc)
 379                 errx(EXIT_FAILURE, _("no filename specified"));
 380
 381         filename = argv[optind++];
 382
 383         if (optind != argc)
 384                 errx(EXIT_FAILURE, _("unexpected number of arguments"));
 385
 386         if (dig) {
 387                 /* for --dig-holes the default is analyze all file */
 388                 if (length == -2LL)
 389                         length = 0;
 390                 if (length < 0)
 391                         errx(EXIT_FAILURE, _("invalid length value specified"));
 392         } else {
 393                 /* it's safer to require the range specification (--length --offset) */
 394                 if (length == -2LL)
 395                         errx(EXIT_FAILURE, _("no length argument specified"));
 396                 if (length <= 0)
 397                         errx(EXIT_FAILURE, _("invalid length value specified"));
 398         }
 399         if (offset < 0)
 400                 errx(EXIT_FAILURE, _("invalid offset value specified"));
 401
 402         /* O_CREAT makes sense only for the default fallocate(2) behavior
 403          * when mode is no specified and new space is allocated */
 404         fd = open(filename, O_RDWR | (!dig && !mode ? O_CREAT : 0),
 405                   S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH);
 406         if (fd < 0)
 407                 err(EXIT_FAILURE, _("cannot open %s"), filename);
 408
 409         if (dig)
 410                 dig_holes(fd, offset, length);
 411         else {
 412 #ifdef HAVE_POSIX_FALLOCATE
 413                 if (posix)
 414                         xposix_fallocate(fd, offset, length);
 415                 else
 416 #endif
 417                         xfallocate(fd, mode, offset, length);
 418
 419                 if (verbose) {
 420                         char *str = size_to_human_string(SIZE_SUFFIX_3LETTER | SIZE_SUFFIX_SPACE, length);
 421
 422                         if (mode & FALLOC_FL_PUNCH_HOLE)
 423                                 fprintf(stdout, _("%s: %s (%ju bytes) hole created.\n"),
 424                                                                 filename, str, length);
 425                         else if (mode & FALLOC_FL_COLLAPSE_RANGE)
 426                                 fprintf(stdout, _("%s: %s (%ju bytes) removed.\n"),
 427                                                                 filename, str, length);
 428                         else if (mode & FALLOC_FL_INSERT_RANGE)
 429                                 fprintf(stdout, _("%s: %s (%ju bytes) inserted.\n"),
 430                                                                 filename, str, length);
 431                         else if (mode & FALLOC_FL_ZERO_RANGE)
 432                                 fprintf(stdout, _("%s: %s (%ju bytes) zeroed.\n"),
 433                                                                 filename, str, length);
 434                         else
 435                                 fprintf(stdout, _("%s: %s (%ju bytes) allocated.\n"),
 436                                                                 filename, str, length);
 437                         free(str);
 438                 }
 439         }
 440
 441         if (close_fd(fd) != 0)
 442                 err(EXIT_FAILURE, _("write failed: %s"), filename);
 443
 444         return EXIT_SUCCESS;
 445 }