freezer: do not sync filesystems from freeze_processes
The syncing of filesystems from within the freezer is generally not needed.
Also, if there's an ext3 filesystem loopback-mounted from a FUSE one, the
syncing results in writes to it and deadlocks. Similarly, it will deadlock if
FUSE implements sync.
Change freeze_processes() so that it doesn't execute sys_sync() and make the
suspend and hibernation code path sync filesystems independently of the
freezer.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@ucw.cz>
Cc: Nigel Cunningham <nigel@nigel.suspend2.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/kernel/power/disk.c b/kernel/power/disk.c
index 9348d95..555c0f0 100644
--- a/kernel/power/disk.c
+++ b/kernel/power/disk.c
@@ -313,6 +313,10 @@
if (error)
goto Exit;
+ printk("Syncing filesystems ... ");
+ sys_sync();
+ printk("done.\n");
+
error = prepare_processes();
if (error)
goto Finish;
diff --git a/kernel/power/main.c b/kernel/power/main.c
index fb2412e..3cdf95b 100644
--- a/kernel/power/main.c
+++ b/kernel/power/main.c
@@ -20,6 +20,7 @@
#include <linux/resume-trace.h>
#include <linux/freezer.h>
#include <linux/vmstat.h>
+#include <linux/syscalls.h>
#include "power.h"
@@ -230,9 +231,14 @@
if (!valid_state(state))
return -ENODEV;
+
if (!mutex_trylock(&pm_mutex))
return -EBUSY;
+ printk("Syncing filesystems ... ");
+ sys_sync();
+ printk("done.\n");
+
pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);
if ((error = suspend_prepare()))
goto Unlock;
diff --git a/kernel/power/process.c b/kernel/power/process.c
index 3434940..dba2f3a 100644
--- a/kernel/power/process.c
+++ b/kernel/power/process.c
@@ -191,7 +191,6 @@
if (error)
return error;
- sys_sync();
error = try_to_freeze_tasks(FREEZER_KERNEL_THREADS);
if (error)
return error;
diff --git a/kernel/power/user.c b/kernel/power/user.c
index bd0723a..5bd321b 100644
--- a/kernel/power/user.c
+++ b/kernel/power/user.c
@@ -153,6 +153,10 @@
mutex_lock(&pm_mutex);
error = pm_notifier_call_chain(PM_HIBERNATION_PREPARE);
if (!error) {
+ printk("Syncing filesystems ... ");
+ sys_sync();
+ printk("done.\n");
+
error = freeze_processes();
if (error)
thaw_processes();