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         printf(USAGE_HELP_OPTIONS(22));
 105
 106         printf(USAGE_MAN_TAIL("fallocate(1)"));
 107
 108         exit(EXIT_SUCCESS);
 109 }
 110
 111 static loff_t cvtnum(char *s)
 112 {
 113         uintmax_t x;
 114
 115         if (strtosize(s, &x))
 116                 return -1LL;
 117
 118         return x;
 119 }
 120
 121 static void xfallocate(int fd, int mode, off_t offset, off_t length)
 122 {
 123         int error;
 124
 125 #ifdef HAVE_FALLOCATE
 126         error = fallocate(fd, mode, offset, length);
 127 #else
 128         error = syscall(SYS_fallocate, fd, mode, offset, length);
 129 #endif
 130         /*
 131          * EOPNOTSUPP: The FALLOC_FL_KEEP_SIZE is unsupported
 132          * ENOSYS: The filesystem does not support sys_fallocate
 133          */
 134         if (error < 0) {
 135                 if ((mode & FALLOC_FL_KEEP_SIZE) && errno == EOPNOTSUPP)
 136                         errx(EXIT_FAILURE, _("fallocate failed: keep size mode is unsupported"));
 137                 err(EXIT_FAILURE, _("fallocate failed"));
 138         }
 139 }
 140
 141 #ifdef HAVE_POSIX_FALLOCATE
 142 static void xposix_fallocate(int fd, off_t offset, off_t length)
 143 {
 144         int error = posix_fallocate(fd, offset, length);
 145         if (error < 0) {
 146                 err(EXIT_FAILURE, _("fallocate failed"));
 147         }
 148 }
 149 #endif
 150
 151 /* The real buffer size has to be bufsize + sizeof(uintptr_t) */
 152 static int is_nul(void *buf, size_t bufsize)
 153 {
 154         typedef uintptr_t word;
 155         void const *vp;
 156         char const *cbuf = buf, *cp;
 157         word const *wp = buf;
 158
 159         /* set sentinel */
 160         memset((char *) buf + bufsize, '\1', sizeof(word));
 161
 162         /* Find first nonzero *word*, or the word with the sentinel.  */
 163         while (*wp++ == 0)
 164                 continue;
 165
 166         /* Find the first nonzero *byte*, or the sentinel.  */
 167         vp = wp - 1;
 168         cp = vp;
 169
 170         while (*cp++ == 0)
 171                 continue;
 172
 173         return cbuf + bufsize < cp;
 174 }
 175
 176 static void dig_holes(int fd, off_t file_off, off_t len)
 177 {
 178         off_t file_end = len ? file_off + len : 0;
 179         off_t hole_start = 0, hole_sz = 0;
 180         uintmax_t ct = 0;
 181         size_t  bufsz;
 182         char *buf;
 183         struct stat st;
 184 #if defined(POSIX_FADV_SEQUENTIAL) && defined(HAVE_POSIX_FADVISE)
 185         off_t cache_start = file_off;
 186         /*
 187          * We don't want to call POSIX_FADV_DONTNEED to discard cached
 188          * data in PAGE_SIZE steps. IMHO it's overkill (too many syscalls).
 189          *
 190          * Let's assume that 1MiB (on system with 4K page size) is just
 191          * a good compromise.
 192          *                                          -- kzak Feb-2014
 193          */
 194         const size_t cachesz = getpagesize() * 256;
 195 #endif
 196
 197         if (fstat(fd, &st) != 0)
 198                 err(EXIT_FAILURE, _("stat of %s failed"), filename);
 199
 200         bufsz = st.st_blksize;
 201
 202         if (lseek(fd, file_off, SEEK_SET) < 0)
 203                 err(EXIT_FAILURE, _("seek on %s failed"), filename);
 204
 205         /* buffer + extra space for is_nul() sentinel */
 206         buf = xmalloc(bufsz + sizeof(uintptr_t));
 207         while (file_end == 0 || file_off < file_end) {
 208                 /*
 209                  * Detect data area (skip holes)
 210                  */
 211                 off_t end, off;
 212
 213                 off = lseek(fd, file_off, SEEK_DATA);
 214                 if ((off == -1 && errno == ENXIO) ||
 215                     (file_end && off >= file_end))
 216                         break;
 217
 218                 end = lseek(fd, off, SEEK_HOLE);
 219                 if (file_end && end > file_end)
 220                         end = file_end;
 221
 222 #if defined(POSIX_FADV_SEQUENTIAL) && defined(HAVE_POSIX_FADVISE)
 223                 posix_fadvise(fd, off, end, POSIX_FADV_SEQUENTIAL);
 224 #endif
 225                 /*
 226                  * Dig holes in the area
 227                  */
 228                 while (off < end) {
 229                         ssize_t rsz = pread(fd, buf, bufsz, off);
 230                         if (rsz < 0 && errno)
 231                                 err(EXIT_FAILURE, _("%s: read failed"), filename);
 232                         if (end && rsz > 0 && off > end - rsz)
 233                                 rsz = end - off;
 234                         if (rsz <= 0)
 235                                 break;
 236
 237                         if (is_nul(buf, rsz)) {
 238                                 if (!hole_sz)                           /* new hole detected */
 239                                         hole_start = off;
 240                                 hole_sz += rsz;
 241                          } else if (hole_sz) {
 242                                 xfallocate(fd, FALLOC_FL_PUNCH_HOLE|FALLOC_FL_KEEP_SIZE,
 243                                            hole_start, hole_sz);
 244                                 ct += hole_sz;
 245                                 hole_sz = hole_start = 0;
 246                         }
 247
 248 #if defined(POSIX_FADV_DONTNEED) && defined(HAVE_POSIX_FADVISE)
 249                         /* discard cached data */
 250                         if (off - cache_start > (off_t) cachesz) {
 251                                 size_t clen = off - cache_start;
 252
 253                                 clen = (clen / cachesz) * cachesz;
 254                                 posix_fadvise(fd, cache_start, clen, POSIX_FADV_DONTNEED);
 255                                 cache_start = cache_start + clen;
 256                         }
 257 #endif
 258                         off += rsz;
 259                 }
 260                 if (hole_sz) {
 261                         xfallocate(fd, FALLOC_FL_PUNCH_HOLE|FALLOC_FL_KEEP_SIZE,
 262                                         hole_start, hole_sz);
 263                         ct += hole_sz;
 264                 }
 265                 file_off = off;
 266         }
 267
 268         free(buf);
 269
 270         if (verbose) {
 271                 char *str = size_to_human_string(SIZE_SUFFIX_3LETTER | SIZE_SUFFIX_SPACE, ct);
 272                 fprintf(stdout, _("%s: %s (%ju bytes) converted to sparse holes.\n"),
 273                                 filename, str, ct);
 274                 free(str);
 275         }
 276 }
 277
 278 int main(int argc, char **argv)
 279 {
 280         int     c;
 281         int     fd;
 282         int     mode = 0;
 283         int     dig = 0;
 284         int posix = 0;
 285         loff_t  length = -2LL;
 286         loff_t  offset = 0;
 287
 288         static const struct option longopts[] = {
 289             { "help",           no_argument,       NULL, 'h' },
 290             { "version",        no_argument,       NULL, 'V' },
 291             { "keep-size",      no_argument,       NULL, 'n' },
 292             { "punch-hole",     no_argument,       NULL, 'p' },
 293             { "collapse-range", no_argument,       NULL, 'c' },
 294             { "dig-holes",      no_argument,       NULL, 'd' },
 295             { "insert-range",   no_argument,       NULL, 'i' },
 296             { "zero-range",     no_argument,       NULL, 'z' },
 297             { "offset",         required_argument, NULL, 'o' },
 298             { "length",         required_argument, NULL, 'l' },
 299             { "posix",          no_argument,       NULL, 'x' },
 300             { "verbose",        no_argument,       NULL, 'v' },
 301             { NULL, 0, NULL, 0 }
 302         };
 303
 304         static const ul_excl_t excl[] = {       /* rows and cols in ASCII order */
 305                 { 'c', 'd', 'p', 'z' },
 306                 { 'c', 'n' },
 307                 { 'x', 'c', 'd', 'i', 'n', 'p', 'z'},
 308                 { 0 }
 309         };
 310         int excl_st[ARRAY_SIZE(excl)] = UL_EXCL_STATUS_INIT;
 311
 312         setlocale(LC_ALL, "");
 313         bindtextdomain(PACKAGE, LOCALEDIR);
 314         textdomain(PACKAGE);
 315         close_stdout_atexit();
 316
 317         while ((c = getopt_long(argc, argv, "hvVncpdizxl:o:", longopts, NULL))
 318                         != -1) {
 319
 320                 err_exclusive_options(c, longopts, excl, excl_st);
 321
 322                 switch(c) {
 323                 case 'c':
 324                         mode |= FALLOC_FL_COLLAPSE_RANGE;
 325                         break;
 326                 case 'd':
 327                         dig = 1;
 328                         break;
 329                 case 'i':
 330                         mode |= FALLOC_FL_INSERT_RANGE;
 331                         break;
 332                 case 'l':
 333                         length = cvtnum(optarg);
 334                         break;
 335                 case 'n':
 336                         mode |= FALLOC_FL_KEEP_SIZE;
 337                         break;
 338                 case 'o':
 339                         offset = cvtnum(optarg);
 340                         break;
 341                 case 'p':
 342                         mode |= FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE;
 343                         break;
 344                 case 'z':
 345                         mode |= FALLOC_FL_ZERO_RANGE;
 346                         break;
 347                 case 'x':
 348 #ifdef HAVE_POSIX_FALLOCATE
 349                         posix = 1;
 350                         break;
 351 #else
 352                         errx(EXIT_FAILURE, _("posix_fallocate support is not compiled"));
 353 #endif
 354                 case 'v':
 355                         verbose++;
 356                         break;
 357
 358                 case 'h':
 359                         usage();
 360                 case 'V':
 361                         print_version(EXIT_SUCCESS);
 362                 default:
 363                         errtryhelp(EXIT_FAILURE);
 364                 }
 365         }
 366
 367         if (optind == argc)
 368                 errx(EXIT_FAILURE, _("no filename specified"));
 369
 370         filename = argv[optind++];
 371
 372         if (optind != argc)
 373                 errx(EXIT_FAILURE, _("unexpected number of arguments"));
 374
 375         if (dig) {
 376                 /* for --dig-holes the default is analyze all file */
 377                 if (length == -2LL)
 378                         length = 0;
 379                 if (length < 0)
 380                         errx(EXIT_FAILURE, _("invalid length value specified"));
 381         } else {
 382                 /* it's safer to require the range specification (--length --offset) */
 383                 if (length == -2LL)
 384                         errx(EXIT_FAILURE, _("no length argument specified"));
 385                 if (length <= 0)
 386                         errx(EXIT_FAILURE, _("invalid length value specified"));
 387         }
 388         if (offset < 0)
 389                 errx(EXIT_FAILURE, _("invalid offset value specified"));
 390
 391         /* O_CREAT makes sense only for the default fallocate(2) behavior
 392          * when mode is no specified and new space is allocated */
 393         fd = open(filename, O_RDWR | (!dig && !mode ? O_CREAT : 0),
 394                   S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH);
 395         if (fd < 0)
 396                 err(EXIT_FAILURE, _("cannot open %s"), filename);
 397
 398         if (dig)
 399                 dig_holes(fd, offset, length);
 400 #ifdef HAVE_POSIX_FALLOCATE
 401         else if (posix)
 402                 xposix_fallocate(fd, offset, length);
 403 #endif
 404         else
 405                 xfallocate(fd, mode, offset, length);
 406
 407         if (close_fd(fd) != 0)
 408                 err(EXIT_FAILURE, _("write failed: %s"), filename);
 409
 410         return EXIT_SUCCESS;
 411 }