On Sun, Nov 02, 2014 at 08:26:24PM +0000, Sami Kerola wrote:
> -static int swapoff_by_label(const char *label, int quiet)
> +static int swapoff_by(const char *type, const char *request, int quiet)
> {
> - const char *special = mnt_resolve_tag("LABEL", label, mntcache);
> - return special ? do_swapoff(special, quiet, CANONIC) : cannot_find(label);
> -}
> + struct libmnt_table *tb = get_swaps();
> + struct libmnt_iter *itr = mnt_new_iter(MNT_ITER_BACKWARD);
> + struct libmnt_fs *fs;
> + int ret = 0, notfound = -1;
>
> -static int swapoff_by_uuid(const char *uuid, int quiet)
> -{
> - const char *special = mnt_resolve_tag("UUID", uuid, mntcache);
> - return special ? do_swapoff(special, quiet, CANONIC) : cannot_find(uuid);
> + while (tb && mnt_table_find_next_fs(tb, itr, match_swap, NULL, &fs) == 0) {
> + const char *dev = mnt_fs_get_source(fs);
> + blkid_probe pr;
> + const char *data;
> +
> + pr = get_swap_prober(dev);
> + blkid_probe_lookup_value(pr, type, &data, NULL);
> + if (data && !strcmp(request, data)) {
> + notfound = 0;
> + ret |= do_swapoff(dev, quiet, CANONIC);
> + }
> + }
> + ret += notfound;
> + return !ret ? 0 : cannot_find(request);
> }
You have forced all swapoff to use /proc/swaps to translate
UUID/LABEL to device or file name. It's bad idea because
* it's expensive, mnt_resolve_* function uses udev symlinks, one
readlink() is faster than libblkid machinery
* dependence on /proc/swaps should be optional, the /proc filesystem
does not have to be mounted
IMHO it would be better to use libblkid and /proc/swaps as fallback
solution only.
> static void __attribute__ ((__noreturn__)) usage(FILE * out)
> @@ -118,7 +130,7 @@ static int swapoff_all(void)
>
> while (tb && mnt_table_find_next_fs(tb, itr, match_swap, NULL, &fs) == 0) {
> if (!is_active_swap(mnt_fs_get_source(fs)))
> - do_swapoff(mnt_fs_get_source(fs), QUIET, !CANONIC);
> + do_swapoff(mnt_fs_get_source(fs), QUIET, CANONIC);
> }
this seems like typo (or do you expect that all fstab stuff is
canonical?)
> for (i = 0; i < numof_labels(); i++)
> - status |= swapoff_by_label(get_label(i), !QUIET);
> + status |= swapoff_by("LABEL", get_label(i), !QUIET);
>
> for (i = 0; i < numof_uuids(); i++)
> - status |= swapoff_by_uuid(get_uuid(i), !QUIET);
> + status |= swapoff_by("UUID", get_uuid(i), !QUIET);
I like the idea to have only one swapoff_by() function.
> while (*argv != NULL)
> status |= do_swapoff(*argv++, !QUIET, !CANONIC);
BTW, you have no changed tags resolving in do_swapoff(), so I guess
swaponff UUID=<uuid>
does not work with your patch, the patch fixes only -U <uuid> use
case.
I have applied a little different patch to fix the problem.
Karel
>From 52f2fd9bcc9bbc2a0234114f11870d943de76652 Mon Sep 17 00:00:00 2001
From: Karel Zak <kzak@xxxxxxxxxx>
Date: Fri, 7 Nov 2014 12:08:11 +0100
Subject: [PATCH] swapoff: swapoff swap files by LABEL and UUID
# swapon --show=NAME,UUID
NAME UUID
/dev/sda3 8d52fca3-bf48-41d6-b826-2315e518a305
/home/fs-images/2g.img 6fa72b96-b802-441f-a31c-091d65c0212c
# swapoff UUID=6fa72b96-b802-441f-a31c-091d65c0212c
swapoff: cannot find the device for UUID=6fa72b96-b802-441f-a31c-091d65c0212c
Reported-by: Sami Kerola <kerolasa@xxxxxx>
Signed-off-by: Karel Zak <kzak@xxxxxxxxxx>
---
sys-utils/Makemodule.am | 13 +++++++--
sys-utils/swapoff.c | 74 +++++++++++++++++++++++++++++++++++++++++--------
2 files changed, 73 insertions(+), 14 deletions(-)
diff --git a/sys-utils/Makemodule.am b/sys-utils/Makemodule.am
index f540d38..12fa632 100644
--- a/sys-utils/Makemodule.am
+++ b/sys-utils/Makemodule.am
@@ -279,9 +279,16 @@ swapon_LDADD = $(LDADD) \
swapoff_SOURCES = \
sys-utils/swapoff.c \
sys-utils/swapon-common.c \
- sys-utils/swapon-common.h
-swapoff_CFLAGS = $(AM_CFLAGS) -I$(ul_libmount_incdir)
-swapoff_LDADD = $(LDADD) libmount.la
+ sys-utils/swapon-common.h \
+ lib/swapprober.c \
+ include/swapprober.h
+swapoff_CFLAGS = $(AM_CFLAGS) \
+ -I$(ul_libblkid_incdir) \
+ -I$(ul_libmount_incdir)
+swapoff_LDADD = $(LDADD) \
+ libmount.la \
+ libblkid.la \
+ libcommon.la
endif
if BUILD_LSCPU
diff --git a/sys-utils/swapoff.c b/sys-utils/swapoff.c
index 182ce95..b725462 100644
--- a/sys-utils/swapoff.c
+++ b/sys-utils/swapoff.c
@@ -8,8 +8,10 @@
#include "nls.h"
#include "c.h"
+#include "xalloc.h"
#include "closestream.h"
+#include "swapprober.h"
#include "swapon-common.h"
#ifndef SWAPON_HAS_TWO_ARGS
@@ -24,6 +26,58 @@ static int all;
#define QUIET 1
#define CANONIC 1
+/*
+ * This function works like mnt_resolve_tag(), but it's able to read UUiD/LABEL
+ * from regular swap files too (according to entries in /proc/swaps). Note that
+ * mnt_resolve_tag() and mnt_resolve_spec() works with system visible block
+ * devices only.
+ */
+static char *swapoff_resolve_tag(const char *name, const char *value,
+ struct libmnt_cache *cache)
+{
+ char *path;
+ struct libmnt_table *tb;
+ struct libmnt_iter *itr;
+ struct libmnt_fs *fs;
+
+ /* this is usual case for block devices (and it's really fast as it uses
+ * udev /dev/disk/by-* symlinks by default */
+ path = mnt_resolve_tag(name, value, cache);
+ if (path)
+ return path;
+
+ /* try regular files from /proc/swaps */
+ tb = get_swaps();
+ if (!tb)
+ return NULL;
+
+ itr = mnt_new_iter(MNT_ITER_BACKWARD);
+ if (!itr)
+ err(EXIT_FAILURE, _("failed to initialize libmount iterator"));
+
+ while (tb && mnt_table_next_fs(tb, itr, &fs) == 0) {
+ blkid_probe pr = NULL;
+ const char *src = mnt_fs_get_source(fs);
+ const char *type = mnt_fs_get_swaptype(fs);
+ const char *data = NULL;
+
+ if (!src || !type || strcmp(type, "file") != 0)
+ continue;
+ pr = get_swap_prober(src);
+ if (!pr)
+ continue;
+ blkid_probe_lookup_value(pr, name, &data, NULL);
+ if (data && strcmp(data, value) == 0)
+ path = xstrdup(src);
+ blkid_free_probe(pr);
+ if (path)
+ break;
+ }
+
+ mnt_free_iter(itr);
+ return path;
+}
+
static int do_swapoff(const char *orig_special, int quiet, int canonic)
{
const char *special = orig_special;
@@ -32,7 +86,11 @@ static int do_swapoff(const char *orig_special, int quiet, int canonic)
printf(_("swapoff %s\n"), orig_special);
if (!canonic) {
+ char *n, *v;
+
special = mnt_resolve_spec(orig_special, mntcache);
+ if (!special && blkid_parse_tag_string(orig_special, &n, &v) == 0)
+ special = swapoff_resolve_tag(n, v, mntcache);
if (!special)
return cannot_find(orig_special);
}
@@ -49,16 +107,10 @@ static int do_swapoff(const char *orig_special, int quiet, int canonic)
return -1;
}
-static int swapoff_by_label(const char *label, int quiet)
-{
- const char *special = mnt_resolve_tag("LABEL", label, mntcache);
- return special ? do_swapoff(special, quiet, CANONIC) : cannot_find(label);
-}
-
-static int swapoff_by_uuid(const char *uuid, int quiet)
+static int swapoff_by(const char *name, const char *value, int quiet)
{
- const char *special = mnt_resolve_tag("UUID", uuid, mntcache);
- return special ? do_swapoff(special, quiet, CANONIC) : cannot_find(uuid);
+ const char *special = swapoff_resolve_tag(name, value, mntcache);
+ return special ? do_swapoff(special, quiet, CANONIC) : cannot_find(value);
}
static void __attribute__ ((__noreturn__)) usage(FILE * out)
@@ -178,10 +230,10 @@ int main(int argc, char *argv[])
mntcache = mnt_new_cache();
for (i = 0; i < numof_labels(); i++)
- status |= swapoff_by_label(get_label(i), !QUIET);
+ status |= swapoff_by("LABEL", get_label(i), !QUIET);
for (i = 0; i < numof_uuids(); i++)
- status |= swapoff_by_uuid(get_uuid(i), !QUIET);
+ status |= swapoff_by("UUID", get_uuid(i), !QUIET);
while (*argv != NULL)
status |= do_swapoff(*argv++, !QUIET, !CANONIC);
--
1.9.3
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