3 # Copyright (c) 2000-2001 Silicon Graphics, Inc. All Rights Reserved.
6 # Fill a filesystem, or write a specified number of bits.
7 # Script runs deterministically given a seed for the random number
8 # generator. Will generate the same set of directories and files,
9 # with the only source of variation the precise point at which the
10 # filesystem fills up. When used with XFS filesystems, and when
11 # the filesize is small, XFS pre-allocation may cause the filesystem
12 # to "fill up" before the actual disk space is gone. Using this
13 # script repeatedly, with a delay between invocations, to account
14 # for extent flushing, will allow more of the filesystem to be filled.
16 # All generated files are checksummed and this sum is stored in the
17 # filename (files are named: <sequence number>.<checksum>.data.
18 # Normally script is invoked using the --list option, which causes all
19 # data files to be written to standard output (--list=-) or a file
20 # (--list=filename). This list can be fed into fill2fs_check, which
21 # recomputes the checksums and flags any errors.
23 # The --stddev=0 forces all files to be precisely --filesize bytes in
24 # length, some other value (--stddev=val) produces filesizes with a
25 # normal distribution with standard deviation val. If not specified
26 # most file sizes are set to lie within 30% of the requested file size.
28 # fill2fs is not guaranteed to write the requested number of bytes, or
29 # fill the filesystem completely. However, it and fill2 are both very
30 # careful about establishing when write operations fail. When the
31 # --verbose option is used the number of bytes "actually written"
32 # is guaranteed to be the number of bytes on disk.
41 # fsinfo: get filesystem info put it into the global namespace, initialises:
42 # $dev, $type, $blocks, $used, $avail, $cap, $mnt, $mnt_options
43 # $fsblocks, $fsblocksize, $agblocks, $agcount, $imax_pct, $logblocks
44 # $logstart, $internal
46 # if $verbose is set then output fs info to STDERR
52 # filesystem space and mount point
54 $cmd = "df -P -T --block-size=512";
55 chomp($_ = `$cmd $file | tail -1`);
56 $n = ($dev, $type, $blocks, $used, $avail, $cap, $mnt) = split(/ +/);
57 die("df failed") if ($n != 7);
59 if ($fscheck && $type ne "xfs") {
60 die("Error: $progname: filesystem is not xfs")
63 # how was this filesystem mounted
64 $_ = `grep $dev /etc/mtab`;
66 $mnt_options = $mtab[3];
68 # if we're running as root run xfs_db on the filesystem
70 # xfs_db: read only, use the default superblock, print everything
71 die("Error: $progname: can't read device: \"$dev\"\n") if (! -r $dev);
72 $_=`xfs_db -r -c sb -c p $dev`;
73 # multiline matching ^$ refers to individual lines...
74 ($fsblocks) = /^dblocks = (\d+)$/m;
75 ($fsblocksize) = /^blocksize = (\d+)$/m;
76 ($agblocks) = /^agblocks = (\d+)$/m;
77 ($agcount) = /^agcount = (\d+)$/m;
78 ($imax_pct) = /^imax_pct = (\d+)$/m;
79 ($logblocks) = /^logblocks = (\d+)$/m;
80 ($logstart) = /^logstart = (\d+)$/m;
81 $internal = $logstart > 0 ? " (internal)" : "";
83 $verbose && print STDERR <<"EOF"
84 Filesystem information:
85 type=$type; device=$dev
86 mount point=$mnt; mount options=$mnt_options
87 percent full=$cap; size (512 byte blocks)=$blocks; used=$used; avail=$avail
88 total filesystem size (fs blocks)=$fsblocks; fs block size=$fsblocksize; imax_pct=$imax_pct
89 agcount=$agcount; agblocks=$agblocks; logblocks=$logblocks; logstart=$logstart$internal
95 # returns numbers with a normal distribution
101 for ($i = 0; $i < 12; $i++) {
105 $x = $mean + $stddev * $x;
110 # determine script location and find fill2
114 chomp($_ = `which fill2 2>&1 | head -1`);
120 # in the same directory - get absolute path
121 chomp($dirname = dirname $0);
122 if ($dirname =~ m!^/.*!) {
123 $fill2 = $dirname . "/fill2";
127 $fill2 = $cwd . "/" . $dirname . "/fill2";
130 die("Error: $progname: can't find fill2, tried \"$fill2\"\n");
139 GetOptions("bytes=f" => \$bytes,
141 "filesize=i" => \$filesize,
145 "fscheck!" => \$fscheck,
146 "percent=f" => \$percentage,
148 "stddev=i" => \$stddev,
149 "sync=i" => \$sync_bytes,
150 "verbose!" => \$verbose);
153 # check/remove output directory, get filesystem info
155 || (! defined $root && @ARGV != 1)
156 || (defined $root && @ARGV == 1))
158 # newline at end of die message suppresses line number
159 print STDERR <<"EOF";
160 Usage: $progname [options] root_dir
162 --bytes=num total number of bytes to write
163 --dir=name where to write files
164 --filesize=num set all files to num bytes in size
165 --force overwrite any existing files
166 --help print this help message
167 --list=filename store created files to filename (- for stdout)
168 --percent=num percentage of filesystem to fill
169 --seed=num seed for random number generator
170 --stddev set file size standard deviation
171 --sync=num sync every num bytes written
172 --verbose verbose output
174 exit(1) unless defined $help;
182 # lots of boring argument checking
185 # root directory and filesystem info
186 $root = $ARGV[0] if (@ARGV == 1);
189 die("Error: $progname: \"$root\" already exists\n");
192 $verbose && print STDERR "Removing \"$root\"... ";
193 system("rm -rf $root");
194 $verbose && print STDERR "done\n";
197 chomp($root_dir = dirname $root);
200 # $list can be "-" for stdout, perl open ">-" opens stdout
201 open LIST, ">$list" if (defined $list);
203 # how many bytes should we write
204 if (defined $bytes && defined $percentage) {
205 die("Error: $progname: can't specify --bytes and --percent\n");
208 if (defined $percentage && ($percentage < 0 || $percentage > 100)) {
209 die("Error: $progname: invalid percentage\n");
211 if (! defined $bytes && ! defined $percentage) {
212 $bytes = $avail * 512;
213 $verbose && print STDERR <<"EOF";
214 Neither --bytes nor --percent specified: filling filesystem ($bytes bytes)
217 elsif (! defined $bytes) {
218 $bytes = int($blocks * 512 * $percentage / 100.0);
220 if (($bytes > $blocks * 512) || (! $force && $bytes > $avail * 512))
222 die("Error: $progname: not enough free disk space, disk is $cap full\n");
228 # To get fix sized files set stddev to 0. The default is to make most files
229 # within 30% of the requested filesize (or 4k if filesize is not specified).
230 # Set the standard deviation to be half of the required percentage: ~95% of
231 # samples lie within 2 standard deviations of the mean.
234 $filesize = 4096 if (! defined $filesize);
235 die("Error: $progname: --filesize must be >= 1 byte") if ($filesize < 1);
236 $stddev = 0.5 * 0.3 * $filesize if (! defined $stddev);
237 $seed = time ^ $$ if (! defined $seed);
252 $verbose && print STDERR "Writing $bytes bytes (seed is $seed)... ";
253 while ($total < $bytes) {
256 if (($d == 0 && $r < 0.5) || ($d > 0 && $r >= 0.0 && $r < 2.4)) {
257 # create a new data file
258 $n = sprintf("%04d", $names[$d]++);
263 $size = int(normal($filesize, $stddev));
265 $left = $bytes - $total;
266 $size = 0 if ($size < 0);
267 $size = $left if ($size > $left);
269 # fill2 will fail if the filesystem is full - not an error!
270 $cmd = "$fill2 -d nbytes=$size,linelength=72,seed=$n -b 4k $n";
271 $cmd .= " > /dev/null 2>&1" if (! $verbose);
272 if (system($cmd) != 0) {
274 warn("can't create a file - assuming filesystem is full\n");
276 if (-e $n && unlink($n) != 1) {
277 warn("couldn't delete \"$n\"");
282 ($sum) = split(/ +/);
283 $name = "$n.$sum.data";
284 $cmd = "mv $n $name"; # perl rename failed earlier than using mv
285 $cmd .= " > /dev/null 2>&1" if (! $verbose);
286 if (system($cmd) != 0) {
288 warn("can't rename a file - assuming filesystem is full\n");
290 if (-e $name && unlink($name) != 1) {
291 warn("couldn't delete \"$name\"");
297 printf LIST ("%s/%s\n", $_, $name);
302 if (defined $sync_bytes && int($total / $sync_bytes) > $sync_cnt) {
307 # note that if d==0 create directories more frequently than files
308 elsif (($d == 0 && $r >= 0.5) || ($d > 0 && $r >= 2.4 && $r < 2.7)) {
309 # create a new directory and descend
310 $name = sprintf("%04d.d", $names[$d]++);
311 if (! mkdir($name, 0777)) {
312 warn("can't make a directory - assuming filesystem is full\n");
315 chdir($name) or die();
319 elsif ($r >= 2.7 && $r < 3.0) {
320 # pop up to the parent directory same probability as descend
321 die("Error: $progname: panic: shouldn't be here!") if ($d == 0);
322 chdir("..") or die();
326 # make sure we return to the original working directory
327 chdir($cwd) or die();
328 $verbose && print STDERR "done\n";
329 $verbose && print STDERR "$total bytes (in $files files and $dirs directories) were actually written\n";
331 exit(0) if ($total = $bytes);
332 exit(1) if ($total == 0);
333 exit(2) if ($total > 0 && $total < $bytes);
335 # - to sum all generated data:
336 # find /home/fill/ -name \*data | xargs ls -al | awk '{total = total + $5; } END { printf("total = %d bytes\n", total); }'
337 # - to find any files not of the required size
338 # find . -name \*data -a \! -size 4096c
340 # find ./fill -name \*.data | wc
341 # - count new directories
342 # find ./fill -name \*.d | wc