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List: util-linux-ng
Subject: review - [PATCH] mkswap: remove v0 swap space support
From: Karel Zak <kzak () redhat ! com>
Date: 2009-03-13 14:14:27
Message-ID: 20090313141427.GB5963 () nb ! net ! home
[Download RAW message or body]
If anyone has any objections, please let us know.
Karel
From 4c85aa3a4c26f2a2c33bf16960b548d5bbd5b4bf Mon Sep 17 00:00:00 2001
From: Karel Zak <kzak@redhat.com>
Date: Wed, 11 Mar 2009 15:23:16 +0100
Subject: [PATCH] mkswap: remove v0 swap space support
The kernel has not supported v0 swap space format since 2.5.22. The
new version v1 is supported since 2.1.117.
Signed-off-by: Karel Zak <kzak@redhat.com>
---
disk-utils/mkswap.8 | 24 +++-----
disk-utils/mkswap.c | 176 +++++++-------------------------------------------
2 files changed, 33 insertions(+), 167 deletions(-)
diff --git a/disk-utils/mkswap.8 b/disk-utils/mkswap.8
index 2f5f0a8..2f40531 100644
--- a/disk-utils/mkswap.8
+++ b/disk-utils/mkswap.8
@@ -7,7 +7,7 @@
.SH NAME
mkswap \- set up a Linux swap area
.SH SYNOPSIS
-.BI "mkswap [\-c] [\-v" N "] [\-f] [\-p " PSZ "] [\-L " label "] [\-U " uuid "] " device " [" size "]"
+.BI "mkswap [\-c] [\-f] [\-p " PSZ "] [\-L " label "] [\-U " uuid "] " device " [" size "]"
.SH DESCRIPTION
.B mkswap
sets up a Linux swap area on a device or in a file.
@@ -138,23 +138,15 @@ Specify the page size to use.
Specify a label, to allow swapon by label.
(Only for new style swap areas.)
.TP
-.B \-v0
-Create an old style swap area.
-.TP
-.B \-v1
-Create a new style swap area.
+.B \-v0, \-v1
+Specify the swap space version. This option is deprecated and \-v1 is
+supported only.
-.LP
-If no \-v option is given,
-.B mkswap
-will default to new style, but use old style if the current kernel
-is older than 2.1.117 (and also if PAGE_SIZE is less than 2048).
-The new style header does not touch the first block, so may be
-preferable, in case you have a boot loader or disk label there.
-If you need to use both 2.0 and 2.2 kernels, use the \-v0 option
-when creating the swapspace.
+The kernel has not supported v0 swap space format since 2.5.22. The new version
+v1 is supported since 2.1.117.
-Version 0 (-v0) swap space format is no longer supported in 2.5+ kernels.
+The new v1 style header does not touch the first block, so may be
+preferable, in case you have a boot loader or disk label there.
.TP
.B \-U uuid
diff --git a/disk-utils/mkswap.c b/disk-utils/mkswap.c
index b5294be..6e151af 100644
--- a/disk-utils/mkswap.c
+++ b/disk-utils/mkswap.c
@@ -64,7 +64,6 @@ static int DEV = -1;
static unsigned long long PAGES = 0;
static unsigned long badpages = 0;
static int check = 0;
-static int version = -1;
#define SELINUX_SWAPFILE_TYPE "swapfile_t"
@@ -213,7 +212,6 @@ write_uuid_and_label(unsigned char *uuid, char *volume_name) {
* swap space as it can handle, but until 2.3.4 it would return an error
* to swapon() if the swapspace was too large.
*/
-#define V0_MAX_PAGES (8 * (pagesize - 10))
/* Before 2.2.0pre9 */
#define V1_OLD_MAX_PAGES ((0x7fffffff / pagesize) - 1)
/* Since 2.2.0pre9, before 2.3.4:
@@ -266,69 +264,10 @@ It is roughly 2GB on i386, PPC, m68k, ARM, 1GB on sparc, 512MB on mips,
#define MAX_BADPAGES ((pagesize-1024-128*sizeof(int)-10)/sizeof(int))
#define MIN_GOODPAGES 10
-/*
- * One more point of lossage - Linux swapspace really is a mess.
- * The definition of the bitmap used is architecture dependent,
- * and requires one to know whether the machine is bigendian,
- * and if so, whether it will use 32-bit or 64-bit units in
- * test_bit().
- * davem writes: "... is based upon an unsigned long type of
- * the cpu and the native endianness".
- * So, it seems we can write `unsigned long' below.
- * However, sparc64 uses 64-bit units in the kernel, while
- * mkswap may have been translated with 32-bit longs. Thus,
- * we need an explicit test for version 0 swap on sparc64.
- */
-
-static void
-bit_set (unsigned long *addr, unsigned int nr) {
- unsigned int r, m;
-
- if(is_be64()) {
- unsigned long long *bitmap = (unsigned long long *) addr;
- unsigned long long bitnum = (unsigned long long) nr;
- unsigned long long rl, ml;
-
- bitmap += bitnum / (8 * sizeof(long long));
- rl = *bitmap;
- ml = 1ULL << (bitnum & (8ULL * sizeof(long long) - 1ULL));
- *bitmap = rl | ml;
- return;
- }
-
- addr += nr / (8 * sizeof(unsigned long));
- r = *addr;
- m = 1 << (nr & (8 * sizeof(unsigned long) - 1));
- *addr = r | m;
-}
-
-static int
-bit_test_and_clear (unsigned long *addr, unsigned int nr) {
- unsigned int r, m;
-
- if(is_be64()) {
- unsigned long long *bitmap = (unsigned long long *) addr;
- unsigned long long bitnum = (unsigned long long) nr;
- unsigned long long rl, ml;
-
- bitmap += bitnum / (8 * sizeof(long long));
- rl = *bitmap;
- ml = 1ULL << (bitnum & (8ULL * sizeof(long long) - 1ULL));
- *bitmap = rl & ~ml;
- return ((rl & ml) != 0ULL);
- }
-
- addr += nr / (8 * sizeof(unsigned long));
- r = *addr;
- m = 1 << (nr & (8 * sizeof(unsigned long) - 1));
- *addr = r & ~m;
- return (r & m) != 0;
-}
-
static void
usage(void) {
fprintf(stderr,
- _("Usage: %s [-c] [-v0|-v1] [-pPAGESZ] [-L label] [-U UUID] /dev/name [blocks]\n"),
+ _("Usage: %s [-c] [-pPAGESZ] [-L label] [-U UUID] /dev/name [blocks]\n"),
program_name);
exit(1);
}
@@ -340,20 +279,10 @@ die(const char *str) {
}
static void
-page_ok(int page) {
- if (version==0)
- bit_set(signature_page, page);
-}
-
-static void
page_bad(int page) {
- if (version == 0)
- bit_test_and_clear(signature_page, page);
- else {
- if (badpages == MAX_BADPAGES)
- die(_("too many bad pages"));
- p->badpages[badpages] = page;
- }
+ if (badpages == MAX_BADPAGES)
+ die(_("too many bad pages"));
+ p->badpages[badpages] = page;
badpages++;
}
@@ -368,10 +297,8 @@ check_blocks(void) {
die(_("Out of memory"));
current_page = 0;
while (current_page < PAGES) {
- if (!check) {
- page_ok(current_page++);
+ if (!check)
continue;
- }
if (do_seek && lseek(DEV,current_page*pagesize,SEEK_SET) !=
current_page*pagesize)
die(_("seek failed in check_blocks"));
@@ -379,7 +306,6 @@ check_blocks(void) {
page_bad(current_page++);
continue;
}
- page_ok(current_page++);
}
if (badpages == 1)
printf(_("one bad page\n"));
@@ -462,6 +388,7 @@ main(int argc, char ** argv) {
unsigned long long sz;
off_t offset;
int force = 0;
+ int version = 1;
char *block_count = 0;
char *pp;
char *opt_label = NULL;
@@ -533,6 +460,12 @@ main(int argc, char ** argv) {
usage();
}
+ if (version != 1) {
+ fprintf(stderr, _("%s: does not support swapspace version %d.\n"),
+ program_name, version);
+ exit(EXIT_FAILURE);
+ }
+
#ifdef HAVE_LIBUUID
if(opt_uuid) {
if (uuid_parse(opt_uuid, uuid_dat) != 0)
@@ -571,28 +504,6 @@ main(int argc, char ** argv) {
exit(1);
}
- if (version == -1) {
- /* labels only for v1 */
- if (opt_label)
- version = 1;
- else
- /* use version 1 as default, if possible */
-#ifdef __linux__
- if (get_linux_version() < KERNEL_VERSION(2,1,117))
- version = 0;
- else
-#endif
- if (pagesize < 2048)
- version = 0;
- else
- version = 1;
- }
- if (version != 0 && version != 1) {
- fprintf(stderr, _("%s: error: unknown version %d\n"),
- program_name, version);
- usage();
- }
-
if (PAGES < MIN_GOODPAGES) {
fprintf(stderr,
_("%s: error: swap area needs to be at least %ld KiB\n"),
@@ -600,15 +511,13 @@ main(int argc, char ** argv) {
usage();
}
- if (version == 0)
- maxpages = V0_MAX_PAGES;
#ifdef __linux__
- else if (get_linux_version() >= KERNEL_VERSION(2,3,4))
+ if (get_linux_version() >= KERNEL_VERSION(2,3,4))
maxpages = UINT_MAX + 1ULL;
else if (get_linux_version() >= KERNEL_VERSION(2,2,1))
maxpages = V1_MAX_PAGES;
-#endif
else
+#endif
maxpages = V1_OLD_MAX_PAGES;
if (PAGES > maxpages) {
@@ -618,13 +527,6 @@ main(int argc, char ** argv) {
program_name, PAGES * pagesize / 1024);
}
- if (opt_label && version == 0) {
- fprintf(stderr,
- _("%s: error: label only with v1 swap area\n"),
- program_name);
- usage();
- }
-
if (stat(device_name, &statbuf) < 0) {
perror(device_name);
exit(EXIT_FAILURE);
@@ -656,52 +558,24 @@ main(int argc, char ** argv) {
exit(1);
}
-#ifdef __sparc__
- if (!force && version == 0) {
- /* Don't overwrite partition table unless forced */
- unsigned char *buffer = (unsigned char *)signature_page;
- unsigned short *q, sum;
-
- if (read(DEV, buffer, 512) != 512)
- die(_("fatal: first page unreadable"));
- if (buffer[508] == 0xDA && buffer[509] == 0xBE) {
- q = (unsigned short *)(buffer + 510);
- for (sum = 0; q >= (unsigned short *) buffer;)
- sum ^= *q--;
- if (!sum) {
- fprintf(stderr, _("\
-%s: Device '%s' contains a valid Sun disklabel.\n\
-This probably means creating v0 swap would destroy your partition table.\n\
-No swap was created. If you really want to create v0 swap on that device,\n\
-use the -f option to force it.\n"),
- program_name, device_name);
- exit(1);
- }
- }
- }
-#endif
-
- if (version == 0 || check)
+ if (check)
check_blocks();
- if (version == 0 && !bit_test_and_clear(signature_page,0))
- die(_("fatal: first page unreadable"));
- if (version == 1) {
- p->version = version;
- p->last_page = PAGES-1;
- p->nr_badpages = badpages;
- }
+
+ p->version = 1;
+ p->last_page = PAGES-1;
+ p->nr_badpages = badpages;
if (badpages > PAGES - MIN_GOODPAGES)
die(_("Unable to set up swap-space: unreadable"));
+
goodpages = PAGES - badpages - 1;
- printf(_("Setting up swapspace version %d, size = %llu KiB\n"),
- version, goodpages * pagesize / 1024);
- write_signature((version == 0) ? "SWAP-SPACE" : "SWAPSPACE2");
+ printf(_("Setting up swapspace version 1, size = %llu KiB\n"),
+ goodpages * pagesize / 1024);
- if (version == 1)
- write_uuid_and_label(uuid, opt_label);
+ write_signature("SWAPSPACE2");
+ write_uuid_and_label(uuid, opt_label);
- offset = ((version == 0) ? 0 : 1024);
+ offset = 1024;
if (lseek(DEV, offset, SEEK_SET) != offset)
die(_("unable to rewind swap-device"));
if (write_all(DEV, (char *) signature_page + offset,
--
1.6.0.6
--
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