Revert "autofs: work around unhappy compat problem on x86-64". Reopens #633423.

svn path=/dists/sid/linux-2.6/; revision=18958

debian/changelog

@@ -25,6 +25,8 @@ linux-2.6 (3.2.16-1) UNRELEASED; urgency=low
     - Ensure that the LOCK code sets exception->inode
     - Ensure that we check lock exclusive/shared type against open modes
   * [x86] i915: Fix integer overflows in i915_gem_{do_execbuffer,execbuffer2}
+  * Revert "autofs: work around unhappy compat problem on x86-64".
+    Reopens #633423.
 
  -- Ben Hutchings <ben@decadent.org.uk>  Mon, 16 Apr 2012 02:27:29 +0100
 

debian/patches/bugfix/all/revert-autofs-work-around-unhappy-compat-problem-on-.patch

@@ -0,0 +1,132 @@
+From: Linus Torvalds <torvalds@linux-foundation.org>
+Date: Sat, 28 Apr 2012 08:29:56 -0700
+Subject: [PATCH] Revert "autofs: work around unhappy compat problem on
+ x86-64"
+
+commit fcbf94b9dedd2ce08e798a99aafc94fec8668161 upstream.
+
+This reverts commit a32744d4abae24572eff7269bc17895c41bd0085.
+
+While that commit was technically the right thing to do, and made the
+x86-64 compat mode work identically to native 32-bit mode (and thus
+fixing the problem with a 32-bit systemd install on a 64-bit kernel), it
+turns out that the automount binaries had workarounds for this compat
+problem.
+
+Now, the workarounds are disgusting: doing an "uname()" to find out the
+architecture of the kernel, and then comparing it for the 64-bit cases
+and fixing up the size of the read() in automount for those.  And they
+were confused: it's not actually a generic 64-bit issue at all, it's
+very much tied to just x86-64, which has different alignment for an
+'u64' in 64-bit mode than in 32-bit mode.
+
+But the end result is that fixing the compat layer actually breaks the
+case of a 32-bit automount on a x86-64 kernel.
+
+There are various approaches to fix this (including just doing a
+"strcmp()" on current->comm and comparing it to "automount"), but I
+think that I will do the one that teaches pipes about a special "packet
+mode", which will allow user space to not have to care too deeply about
+the padding at the end of the autofs packet.
+
+That change will make the compat workaround unnecessary, so let's revert
+it first, and get automount working again in compat mode.  The
+packetized pipes will then fix autofs for systemd.
+
+Reported-and-requested-by: Michael Tokarev <mjt@tls.msk.ru>
+Cc: Ian Kent <raven@themaw.net>
+Cc: stable@kernel.org # for 3.3
+Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
+[bwh: Backported to 3.2: adjust context]
+---
+ fs/autofs4/autofs_i.h  |    1 -
+ fs/autofs4/dev-ioctl.c |    1 -
+ fs/autofs4/inode.c     |    2 --
+ fs/autofs4/waitq.c     |   22 +++-------------------
+ 4 files changed, 3 insertions(+), 23 deletions(-)
+
+diff --git a/fs/autofs4/autofs_i.h b/fs/autofs4/autofs_i.h
+index eb1cc92..d8d8e7b 100644
+--- a/fs/autofs4/autofs_i.h
++++ b/fs/autofs4/autofs_i.h
+@@ -110,7 +110,6 @@ struct autofs_sb_info {
+ 	int sub_version;
+ 	int min_proto;
+ 	int max_proto;
+-	int compat_daemon;
+ 	unsigned long exp_timeout;
+ 	unsigned int type;
+ 	int reghost_enabled;
+diff --git a/fs/autofs4/dev-ioctl.c b/fs/autofs4/dev-ioctl.c
+index 9dacb85..3dfd615 100644
+--- a/fs/autofs4/dev-ioctl.c
++++ b/fs/autofs4/dev-ioctl.c
+@@ -385,7 +385,6 @@ static int autofs_dev_ioctl_setpipefd(struct file *fp,
+ 		sbi->pipefd = pipefd;
+ 		sbi->pipe = pipe;
+ 		sbi->catatonic = 0;
+-		sbi->compat_daemon = is_compat_task();
+ 	}
+ out:
+ 	mutex_unlock(&sbi->wq_mutex);
+--- a/fs/autofs4/inode.c
++++ b/fs/autofs4/inode.c
+@@ -19,7 +19,6 @@
+ #include <linux/parser.h>
+ #include <linux/bitops.h>
+ #include <linux/magic.h>
+-#include <linux/compat.h>
+ #include "autofs_i.h"
+ #include <linux/module.h>
+ 
+@@ -225,7 +224,6 @@ int autofs4_fill_super(struct super_block *s, void *data, int silent)
+ 	set_autofs_type_indirect(&sbi->type);
+ 	sbi->min_proto = 0;
+ 	sbi->max_proto = 0;
+-	sbi->compat_daemon = is_compat_task();
+ 	mutex_init(&sbi->wq_mutex);
+ 	spin_lock_init(&sbi->fs_lock);
+ 	sbi->queues = NULL;
+diff --git a/fs/autofs4/waitq.c b/fs/autofs4/waitq.c
+index 9c098db..da8876d 100644
+--- a/fs/autofs4/waitq.c
++++ b/fs/autofs4/waitq.c
+@@ -91,24 +91,7 @@ static int autofs4_write(struct autofs_sb_info *sbi,
+ 
+ 	return (bytes > 0);
+ }
+-
+-/*
+- * The autofs_v5 packet was misdesigned.
+- *
+- * The packets are identical on x86-32 and x86-64, but have different
+- * alignment. Which means that 'sizeof()' will give different results.
+- * Fix it up for the case of running 32-bit user mode on a 64-bit kernel.
+- */
+-static noinline size_t autofs_v5_packet_size(struct autofs_sb_info *sbi)
+-{
+-	size_t pktsz = sizeof(struct autofs_v5_packet);
+-#if defined(CONFIG_X86_64) && defined(CONFIG_COMPAT)
+-	if (sbi->compat_daemon > 0)
+-		pktsz -= 4;
+-#endif
+-	return pktsz;
+-}
+-
++	
+ static void autofs4_notify_daemon(struct autofs_sb_info *sbi,
+ 				 struct autofs_wait_queue *wq,
+ 				 int type)
+@@ -172,7 +155,8 @@ static void autofs4_notify_daemon(struct autofs_sb_info *sbi,
+ 	{
+ 		struct autofs_v5_packet *packet = &pkt.v5_pkt.v5_packet;
+ 
+-		pktsz = autofs_v5_packet_size(sbi);
++		pktsz = sizeof(*packet);
++
+ 		packet->wait_queue_token = wq->wait_queue_token;
+ 		packet->len = wq->name.len;
+ 		memcpy(packet->name, wq->name.name, wq->name.len);
+-- 
+1.7.10
+

debian/patches/series/base

@@ -192,3 +192,4 @@
 + bugfix/all/NFSv4-Ensure-that-we-check-lock-exclusive-shared-typ.patch
 + bugfix/x86/drm-i915-fix-integer-overflow-in-i915_gem_execbuffer2.patch
 + bugfix/x86/drm-i915-fix-integer-overflow-in-i915_gem_do_execbuffer.patch
++ bugfix/all/revert-autofs-work-around-unhappy-compat-problem-on-.patch