kata-containers/s390-tools
1
0
Fork 0
mirror of https://github.com/ibm-s390-linux/s390-tools.git synced 2026-08-05 02:14:52 +00:00
Code Issues Packages Projects Releases Wiki Activity

zdev: Fix path resolution for multi-mount point file systems

Browse Source 
zdev provides path resolution logic to determine which z-specific
devices contribute to the file system mounted at a specific mount point.
This logic is used by command-line option --by-path, but also to
determine the list of devices needed to enable the root file system.

Path resolution fails when a device provides multiple mount points such
as, for example, when using btrfs subvolumes, or when mounting the same
file system at multiple mount points. The failure is caused by zdev
relying on the MOUNTPOINT attribute of lsblk's output which only
contains a single mount point.

Fix this by making use of lsblk's MOUNTPOINTS attribute that contains
the full list of mount points. Note that MOUNTPOINTS was only introduced
with util-linux v2.37, therefore a fall-back to the old format is
needed.

Fixes: https://github.com/ibm-s390-linux/s390-tools/issues/129
Signed-off-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Reviewed-by: Jan Höppner <hoeppner@linux.ibm.com>
Reviewed-by: Vineeth Vijayan <vneethv@linux.ibm.com>
Reviewed-by: Eduard Shishkin <edward6@linux.ibm.com>
Reported-by: Dan Horák <dan@danny.cz>
Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
This commit is contained in:
Peter Oberparleiter
2022-01-26 11:43:43 +01:00
committed by Jan Höppner
parent d62e075450
commit 1faa5d2957
1 changed files with 54 additions and 8 deletions
Download Patch File Download Diff File Expand all files Collapse all files

62
zdev/src/blkinfo.c
View File

@@ -7,6 +7,7 @@
* it under the terms of the MIT license. See LICENSE for details.
*/
#include <ctype.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
@@ -16,6 +17,7 @@
#include "misc.h"
#define LSBLK_CMDLINE "lsblk -P -o NAME,MAJ:MIN,FSTYPE,UUID,MOUNTPOINT,PKNAME 2>/dev/null"
#define LSBLK_CMDLINE2 "lsblk -P -o NAME,MAJ:MIN,FSTYPE,UUID,MOUNTPOINTS,PKNAME 2>/dev/null"
struct blkinfo {
struct devnode *devnode;
@@ -82,6 +84,26 @@ void blkinfo_print(struct blkinfo *blkinfo, int level)
printf("%*sparent=%s\n", level, "", blkinfo->parent);
}
/* Convert each occurrence of '\xnn' in @str to character with hex code <nn>. */
static void hex_unescape(char *str)
{
unsigned int c;
while ((str = strstr(str, "\\x"))) {
if (isxdigit(str[2]) && isxdigit(str[3]) &&
sscanf(str + 2, "%2x", &c) == 1) {
str[0] = (char)c;
/* Move remainder of str including nul behind <c>. */
memmove(str + /* <c> */ 1,
str + /* '\xnn' */ 4,
strlen(str + 4) + /* <nul> */ 1);
}
str++;
}
}
static char *isolate_keyword(char **line_ptr, const char *keyword)
{
char *start, *end;
@@ -102,9 +124,11 @@ static char *isolate_keyword(char **line_ptr, const char *keyword)
return start;
}
static struct blkinfo *blkinfo_from_line(char *line)
static void add_blkinfos_from_line(struct util_list *blkinfos,
char *line)
{
char *name, *majmin, *fstype, *uuid, *mountpoint, *parent;
char *name, *majmin, *fstype, *uuid, *mountpoint, *mountpoints, *parent;
struct blkinfo *blkinfo;
name = isolate_keyword(&line, "NAME=\"");
majmin = isolate_keyword(&line, "MAJ:MIN=\"");
@@ -113,21 +137,45 @@ static struct blkinfo *blkinfo_from_line(char *line)
fstype = isolate_keyword(&line, "FSTYPE=\"");
uuid = isolate_keyword(&line, "UUID=\"");
mountpoint = isolate_keyword(&line, "MOUNTPOINT=\"");
mountpoints = isolate_keyword(&line, "MOUNTPOINTS=\"");
parent = isolate_keyword(&line, "PKNAME=\"");
return blkinfo_new(name, majmin, fstype, uuid, mountpoint, parent);
if (!mountpoints) {
/* Handle old lsblk output format. */
blkinfo = blkinfo_new(name, majmin, fstype, uuid, mountpoint,
parent);
ptrlist_add(blkinfos, blkinfo);
return;
}
/* Restore newline mount point separator encoded as hex. */
hex_unescape(mountpoints);
/* Represent each mount point as a separate blkinfo to support
* resolution of multi-mount point file systems like btrfs
* subvolumes. */
while ((mountpoint = strsep(&mountpoints, "\n"))) {
blkinfo = blkinfo_new(name, majmin, fstype, uuid, mountpoint,
parent);
ptrlist_add(blkinfos, blkinfo);
}
}
static struct util_list *blkinfos_read(void)
{
char *output, *curr, *next;
struct util_list *blkinfos;
struct blkinfo *blkinfo;
if (cached_blkinfos)
return cached_blkinfos;
output = misc_read_cmd_output(LSBLK_CMDLINE, 0, 1);
output = misc_read_cmd_output(LSBLK_CMDLINE2, 0, 1);
if (output && !*output) {
/* No output might indicate no support for new lsblk command-
* line format - fall back to old format. */
free(output);
output = misc_read_cmd_output(LSBLK_CMDLINE, 0, 1);
}
if (!output)
return NULL;
@@ -136,9 +184,7 @@ static struct util_list *blkinfos_read(void)
/* Iterate over each line. */
next = output;
while ((curr = strsep(&next, "\n"))) {
blkinfo = blkinfo_from_line(curr);
if (blkinfo)
ptrlist_add(blkinfos, blkinfo);
add_blkinfos_from_line(blkinfos, curr);
}
free(output);