133 lines
4.4 KiB
Diff
133 lines
4.4 KiB
Diff
From: Linus Torvalds <torvalds@linux-foundation.org>
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Date: Sat, 28 Apr 2012 08:29:56 -0700
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Subject: [PATCH] Revert "autofs: work around unhappy compat problem on
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x86-64"
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commit fcbf94b9dedd2ce08e798a99aafc94fec8668161 upstream.
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This reverts commit a32744d4abae24572eff7269bc17895c41bd0085.
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While that commit was technically the right thing to do, and made the
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x86-64 compat mode work identically to native 32-bit mode (and thus
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fixing the problem with a 32-bit systemd install on a 64-bit kernel), it
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turns out that the automount binaries had workarounds for this compat
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problem.
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Now, the workarounds are disgusting: doing an "uname()" to find out the
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architecture of the kernel, and then comparing it for the 64-bit cases
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and fixing up the size of the read() in automount for those. And they
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were confused: it's not actually a generic 64-bit issue at all, it's
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very much tied to just x86-64, which has different alignment for an
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'u64' in 64-bit mode than in 32-bit mode.
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But the end result is that fixing the compat layer actually breaks the
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case of a 32-bit automount on a x86-64 kernel.
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There are various approaches to fix this (including just doing a
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"strcmp()" on current->comm and comparing it to "automount"), but I
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think that I will do the one that teaches pipes about a special "packet
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mode", which will allow user space to not have to care too deeply about
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the padding at the end of the autofs packet.
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That change will make the compat workaround unnecessary, so let's revert
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it first, and get automount working again in compat mode. The
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packetized pipes will then fix autofs for systemd.
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Reported-and-requested-by: Michael Tokarev <mjt@tls.msk.ru>
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Cc: Ian Kent <raven@themaw.net>
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Cc: stable@kernel.org # for 3.3
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Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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[bwh: Backported to 3.2: adjust context]
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---
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fs/autofs4/autofs_i.h | 1 -
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fs/autofs4/dev-ioctl.c | 1 -
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fs/autofs4/inode.c | 2 --
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fs/autofs4/waitq.c | 22 +++-------------------
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4 files changed, 3 insertions(+), 23 deletions(-)
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diff --git a/fs/autofs4/autofs_i.h b/fs/autofs4/autofs_i.h
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index eb1cc92..d8d8e7b 100644
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--- a/fs/autofs4/autofs_i.h
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+++ b/fs/autofs4/autofs_i.h
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@@ -110,7 +110,6 @@ struct autofs_sb_info {
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int sub_version;
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int min_proto;
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int max_proto;
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- int compat_daemon;
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unsigned long exp_timeout;
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unsigned int type;
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int reghost_enabled;
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diff --git a/fs/autofs4/dev-ioctl.c b/fs/autofs4/dev-ioctl.c
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index 9dacb85..3dfd615 100644
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--- a/fs/autofs4/dev-ioctl.c
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+++ b/fs/autofs4/dev-ioctl.c
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@@ -385,7 +385,6 @@ static int autofs_dev_ioctl_setpipefd(struct file *fp,
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sbi->pipefd = pipefd;
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sbi->pipe = pipe;
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sbi->catatonic = 0;
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- sbi->compat_daemon = is_compat_task();
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}
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out:
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mutex_unlock(&sbi->wq_mutex);
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--- a/fs/autofs4/inode.c
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+++ b/fs/autofs4/inode.c
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@@ -19,7 +19,6 @@
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#include <linux/parser.h>
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#include <linux/bitops.h>
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#include <linux/magic.h>
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-#include <linux/compat.h>
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#include "autofs_i.h"
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#include <linux/module.h>
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@@ -225,7 +224,6 @@ int autofs4_fill_super(struct super_block *s, void *data, int silent)
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set_autofs_type_indirect(&sbi->type);
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sbi->min_proto = 0;
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sbi->max_proto = 0;
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- sbi->compat_daemon = is_compat_task();
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mutex_init(&sbi->wq_mutex);
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spin_lock_init(&sbi->fs_lock);
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sbi->queues = NULL;
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diff --git a/fs/autofs4/waitq.c b/fs/autofs4/waitq.c
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index 9c098db..da8876d 100644
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--- a/fs/autofs4/waitq.c
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+++ b/fs/autofs4/waitq.c
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@@ -91,24 +91,7 @@ static int autofs4_write(struct autofs_sb_info *sbi,
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return (bytes > 0);
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}
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-
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-/*
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- * The autofs_v5 packet was misdesigned.
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- *
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- * The packets are identical on x86-32 and x86-64, but have different
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- * alignment. Which means that 'sizeof()' will give different results.
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- * Fix it up for the case of running 32-bit user mode on a 64-bit kernel.
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- */
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-static noinline size_t autofs_v5_packet_size(struct autofs_sb_info *sbi)
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-{
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- size_t pktsz = sizeof(struct autofs_v5_packet);
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-#if defined(CONFIG_X86_64) && defined(CONFIG_COMPAT)
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- if (sbi->compat_daemon > 0)
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- pktsz -= 4;
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-#endif
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- return pktsz;
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-}
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-
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+
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static void autofs4_notify_daemon(struct autofs_sb_info *sbi,
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struct autofs_wait_queue *wq,
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int type)
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@@ -172,7 +155,8 @@ static void autofs4_notify_daemon(struct autofs_sb_info *sbi,
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{
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struct autofs_v5_packet *packet = &pkt.v5_pkt.v5_packet;
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- pktsz = autofs_v5_packet_size(sbi);
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+ pktsz = sizeof(*packet);
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+
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packet->wait_queue_token = wq->wait_queue_token;
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packet->len = wq->name.len;
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memcpy(packet->name, wq->name.name, wq->name.len);
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--
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1.7.10
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