85 lines
3.0 KiB
Diff
85 lines
3.0 KiB
Diff
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From c072bd13abbe497d28e4235e2cf416f4aee65754 Mon Sep 17 00:00:00 2001
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From: =?UTF-8?q?Niklas=20Hamb=C3=BCchen?= <mail@nh2.me>
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Date: Mon, 29 Apr 2019 10:23:14 +0200
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Subject: [PATCH 05/20] x86: Find mounts by FS type, not name
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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https://git.kernel.org/pub/scm/utils/kernel/kexec/kexec-tools.git/commit/?id=c072bd13abbe497d28e4235e2cf416f4aee65754
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The name in mount invocations like
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mount -t debugfs debugfs /sys/kernel/debug
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is nothing but convention and cannot be relied upon.
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For example, https://www.kernel.org/doc/Documentation/filesystems/debugfs.txt
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recommends making the name "none" instead:
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mount -t debugfs none /sys/kernel/debug
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and many existing systems use mounts named "none" or otherwise.
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Using `mnt_type` instead of `mnt_fsname` allows kexec to work
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on such systems.
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This fixes another instance of `poweroff` not working on kexec'ed
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kernels because the lack of correctly matched mount results in EFI
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variables not being read and propagated.
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Signed-off-by: Niklas Hambüchen <mail@nh2.me>
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Signed-off-by: Simon Horman <horms@verge.net.au>
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---
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kexec/arch/i386/x86-linux-setup.c | 12 ++++++++----
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1 file changed, 8 insertions(+), 4 deletions(-)
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diff --git a/kexec/arch/i386/x86-linux-setup.c b/kexec/arch/i386/x86-linux-setup.c
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index 74fb0c4..b643c8b 100644
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--- a/kexec/arch/i386/x86-linux-setup.c
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+++ b/kexec/arch/i386/x86-linux-setup.c
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@@ -433,8 +433,12 @@ out:
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* This really only makes sense for virtual filesystems that are only expected
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* to be mounted once (sysfs, debugsfs, proc), as it will return the first
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* instance listed in /proc/mounts, falling back to mtab if absent.
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+ * We search by type and not by name because the name can be anything;
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+ * while setting the name equal to the mount point is common, it cannot be
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+ * relied upon, as even kernel documentation examples recommends using
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+ * "none" as the name e.g. for debugfs.
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*/
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-char *find_mnt_by_fsname(char *fsname)
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+char *find_mnt_by_type(char *type)
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{
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FILE *mtab;
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struct mntent *mnt;
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@@ -448,7 +452,7 @@ char *find_mnt_by_fsname(char *fsname)
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if (!mtab)
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return NULL;
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for(mnt = getmntent(mtab); mnt; mnt = getmntent(mtab)) {
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- if (strcmp(mnt->mnt_fsname, fsname) == 0)
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+ if (strcmp(mnt->mnt_type, type) == 0)
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break;
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}
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mntdir = mnt ? strdup(mnt->mnt_dir) : NULL;
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@@ -463,7 +467,7 @@ static int get_bootparam(void *buf, off_t offset, size_t size)
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char filename[PATH_MAX];
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int err, has_sysfs_params = 0;
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- sysfs_mnt = find_mnt_by_fsname("sysfs");
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+ sysfs_mnt = find_mnt_by_type("sysfs");
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if (sysfs_mnt) {
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snprintf(filename, PATH_MAX, "%s/%s", sysfs_mnt,
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"kernel/boot_params/data");
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@@ -474,7 +478,7 @@ static int get_bootparam(void *buf, off_t offset, size_t size)
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}
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if (!has_sysfs_params) {
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- debugfs_mnt = find_mnt_by_fsname("debugfs");
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+ debugfs_mnt = find_mnt_by_type("debugfs");
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if (!debugfs_mnt)
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return 1;
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snprintf(filename, PATH_MAX, "%s/%s", debugfs_mnt,
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--
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1.8.3.1
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