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fallocate: add FALLOC_FL_ZERO_RANGE support 

Recent Linux kernel supports FALLOC_FL_ZERO_RANGE in fallocate(2).
This patch adds FALLOC_FL_ZERO_RANGE support to fallocate utility,
by introducing a new option -z|--zero-range.

Signed-off-by: Lukas Czerner <lczerner@redhat.com>
This commit is contained in:
Lukas Czerner 2014-04-02 13:31:05 +02:00 committed by Karel Zak
parent 83cc932d74
commit 1fd4f609ee
2 changed files with 33 additions and 6 deletions
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14
sys-utils/fallocate.1
View File

@ -7,6 +7,7 @@ fallocate \- preallocate or deallocate space to a file
.RB [ \-n ]
.RB [ \-p ]
.RB [ \-c ]
.RB [ \-z ]
.RB [ \-o
.IR offset ]
.B \-l
@ -46,6 +47,9 @@ Do not modify the apparent length of the file. This may effectively allocate
blocks past EOF, which can be removed with a truncate.
.IP "\fB\-p, \-\-punch-hole\fP"
Punch holes in the file, the range should not exceed the length of the file.
This option may not be specified at the same time as the
.B \-z
option.
.IP "\fB\-d, \-\-dig-holes\fP"
Detect and dig holes. Makes the file sparse in-place, without using extra disk
space. The minimal size of the hole depends on filesystem I/O block size
@ -61,6 +65,16 @@ Collapse a particular file range to nullify the hole. Extents beyond the range
command does not leave a hole, while \fI\-\-punch-hole\fP leaves a hole
instead of shifting extents. Both offset and length should be aligned to
the block size of filesystem.
.IP "\fB\-z, \-\-zero-range\fP"
Zero range in the file. Regions that span holes in the file will be
preallocated, this includes areas past EOF. Option
.B \-n
can be specified to prevent file length modification. Reads from the range
will return zeros. This option may not be specified at the same time as the
.B \-p
or
.B \-c
option.
.IP "\fB\-o, \-\-offset\fP \fIoffset\fP
Specifies the beginning offset of the allocation, in bytes.
.IP "\fB\-l, \-\-length\fP \fIlength\fP

25
sys-utils/fallocate.c
View File

@ -40,20 +40,24 @@
#if defined(HAVE_LINUX_FALLOC_H) && \
(!defined(FALLOC_FL_KEEP_SIZE) || !defined(FALLOC_FL_PUNCH_HOLE) || \
!defined(FALLOC_FL_COLLAPSE_RANGE))
!defined(FALLOC_FL_COLLAPSE_RANGE) || !defined(FALLOC_FL_ZERO_RANGE))
# include <linux/falloc.h> /* non-libc fallback for FALLOC_FL_* flags */
#endif
#ifndef FALLOC_FL_KEEP_SIZE
# define FALLOC_FL_KEEP_SIZE 1
# define FALLOC_FL_KEEP_SIZE 0x1
#endif
#ifndef FALLOC_FL_PUNCH_HOLE
# define FALLOC_FL_PUNCH_HOLE 2
# define FALLOC_FL_PUNCH_HOLE 0x2
#endif
#ifndef FALLOC_FL_COLLAPSE_RANGE
# define FALLOC_FL_COLLAPSE_RANGE 8
# define FALLOC_FL_COLLAPSE_RANGE 0x8
#endif
#ifndef FALLOC_FL_ZERO_RANGE
# define FALLOC_FL_ZERO_RANGE 0x10
#endif
#include "nls.h"
@ -77,6 +81,7 @@ static void __attribute__((__noreturn__)) usage(FILE *out)
fputs(_(" -n, --keep-size don't modify the length of the file\n"), out);
fputs(_(" -o, --offset <num> offset of the (de)allocation, in bytes\n"), out);
fputs(_(" -p, --punch-hole punch holes in the file\n"), out);
fputs(_(" -z, --zero-range zeroes a range in the file\n"), out);
fputs(_(" -v, --verbose verbose mode\n"), out);
fputs(USAGE_SEPARATOR, out);
@ -270,6 +275,7 @@ int main(int argc, char **argv)
{ "punch-hole", 0, 0, 'p' },
{ "collapse-range", 0, 0, 'c' },
{ "dig-holes", 0, 0, 'd' },
{ "zero-range", 0, 0, 'z' },
{ "offset", 1, 0, 'o' },
{ "length", 1, 0, 'l' },
{ "verbose", 0, 0, 'v' },
@ -281,7 +287,7 @@ int main(int argc, char **argv)
textdomain(PACKAGE);
atexit(close_stdout);
while ((c = getopt_long(argc, argv, "hvVncpdl:o:", longopts, NULL))
while ((c = getopt_long(argc, argv, "hvVncpdzl:o:", longopts, NULL))
!= -1) {
switch(c) {
case 'h':
@ -302,6 +308,9 @@ int main(int argc, char **argv)
case 'd':
dig = 1;
break;
case 'z':
mode |= FALLOC_FL_ZERO_RANGE;
break;
case 'l':
length = cvtnum(optarg);
break;
@ -318,7 +327,8 @@ int main(int argc, char **argv)
}
if (dig) {
if (mode != 0)
errx(EXIT_FAILURE, _("Can't use -p or -n with --dig-holes"));
errx(EXIT_FAILURE,
_("Can't use other modes with --dig-holes"));
if (length == -2LL)
length = 0;
if (length < 0)
@ -333,6 +343,9 @@ int main(int argc, char **argv)
errx(EXIT_FAILURE, _("invalid offset value specified"));
if (optind == argc)
errx(EXIT_FAILURE, _("no filename specified."));
if (mode & ~(FALLOC_FL_ZERO_RANGE | FALLOC_FL_KEEP_SIZE))
errx(EXIT_FAILURE, _("only -n mode can be used with "
"--zero-range"));
filename = argv[optind++];