@@ -1187,6 +1187,8 @@ static inline bool get_active_super(struct super_block *sb)
return active;
}
+static const void *filesystems_freeze_ptr;
+
static void filesystems_freeze_callback(struct super_block *sb, void *unused)
{
if (!sb->s_op->freeze_fs && !sb->s_op->freeze_super)
@@ -1196,9 +1198,11 @@ static void filesystems_freeze_callback(struct super_block *sb, void *unused)
return;
if (sb->s_op->freeze_super)
- sb->s_op->freeze_super(sb, FREEZE_MAY_NEST | FREEZE_HOLDER_KERNEL);
+ sb->s_op->freeze_super(sb, FREEZE_EXCL | FREEZE_HOLDER_KERNEL,
+ filesystems_freeze_ptr);
else
- freeze_super(sb, FREEZE_MAY_NEST | FREEZE_HOLDER_KERNEL);
+ freeze_super(sb, FREEZE_EXCL | FREEZE_HOLDER_KERNEL,
+ filesystems_freeze_ptr);
deactivate_super(sb);
}
@@ -1218,9 +1222,11 @@ static void filesystems_thaw_callback(struct super_block *sb, void *unused)
return;
if (sb->s_op->thaw_super)
- sb->s_op->thaw_super(sb, FREEZE_MAY_NEST | FREEZE_HOLDER_KERNEL);
+ sb->s_op->thaw_super(sb, FREEZE_EXCL | FREEZE_HOLDER_KERNEL,
+ filesystems_freeze_ptr);
else
- thaw_super(sb, FREEZE_MAY_NEST | FREEZE_HOLDER_KERNEL);
+ thaw_super(sb, FREEZE_EXCL | FREEZE_HOLDER_KERNEL,
+ filesystems_freeze_ptr);
deactivate_super(sb);
}
@@ -777,6 +777,7 @@ int hibernate(void)
goto Restore;
ksys_sync_helper();
+ filesystems_freeze();
error = freeze_processes();
if (error)
@@ -841,6 +842,7 @@ int hibernate(void)
error = load_image_and_restore();
}
thaw_processes();
+ filesystems_thaw();
/* Don't bother checking whether freezer_test_done is true */
freezer_test_done = false;
@@ -881,6 +883,8 @@ int hibernate_quiet_exec(int (*func)(void *data), void *data)
if (error)
goto restore;
+ filesystems_freeze();
+
error = freeze_processes();
if (error)
goto exit;
@@ -940,6 +944,7 @@ int hibernate_quiet_exec(int (*func)(void *data), void *data)
thaw_processes();
exit:
+ filesystems_thaw();
pm_notifier_call_chain(PM_POST_HIBERNATION);
restore:
@@ -1028,19 +1033,25 @@ static int software_resume(void)
if (error)
goto Restore;
+ filesystems_freeze();
+
pm_pr_dbg("Preparing processes for hibernation restore.\n");
error = freeze_processes();
- if (error)
+ if (error) {
+ filesystems_thaw();
goto Close_Finish;
+ }
error = freeze_kernel_threads();
if (error) {
thaw_processes();
+ filesystems_thaw();
goto Close_Finish;
}
error = load_image_and_restore();
thaw_processes();
+ filesystems_thaw();
Finish:
pm_notifier_call_chain(PM_POST_RESTORE);
Restore:
@@ -30,6 +30,7 @@
#include <trace/events/power.h>
#include <linux/compiler.h>
#include <linux/moduleparam.h>
+#include <linux/fs.h>
#include "power.h"
@@ -374,6 +375,8 @@ static int suspend_prepare(suspend_state_t state)
if (error)
goto Restore;
+ if (sync_on_suspend_enabled)
+ filesystems_freeze();
trace_suspend_resume(TPS("freeze_processes"), 0, true);
error = suspend_freeze_processes();
trace_suspend_resume(TPS("freeze_processes"), 0, false);
@@ -550,6 +553,8 @@ int suspend_devices_and_enter(suspend_state_t state)
static void suspend_finish(void)
{
suspend_thaw_processes();
+ if (sync_on_suspend_enabled)
+ filesystems_thaw();
pm_notifier_call_chain(PM_POST_SUSPEND);
pm_restore_console();
}
@@ -587,6 +592,7 @@ static int enter_state(suspend_state_t state)
trace_suspend_resume(TPS("sync_filesystems"), 0, true);
ksys_sync_helper();
trace_suspend_resume(TPS("sync_filesystems"), 0, false);
+ filesystems_freeze();
}
pm_pr_dbg("Preparing system for sleep (%s)\n", mem_sleep_labels[state]);
@@ -609,6 +615,8 @@ static int enter_state(suspend_state_t state)
pm_pr_dbg("Finishing wakeup.\n");
suspend_finish();
Unlock:
+ if (sync_on_suspend_enabled)
+ filesystems_thaw();
mutex_unlock(&system_transition_mutex);
return error;
}
Now all the pieces are in place to actually allow the power subsystem to freeze/thaw filesystems during suspend/resume. Filesystems are only frozen and thawed if the power subsystem does actually own the freeze. Othwerwise it risks thawing filesystems it didn't own. This could be done differently be e.g., keepin the filesystems that were actually frozen on a list and then unfreezing them from that list. This is disgustingly unclean though and reeks of an ugly hack. If the filesystem is already frozen by the time we've frozen all userspace processes we don't care to freeze it again. That's userspace's job once the process resumes. We only actually freeze filesystems if we absolutely have to and we ignore other failures to freeze for now. We could bubble up errors and fail suspend/resume if the error isn't EBUSY (aka it's already frozen) but I don't think that this is worth it. Filesystem freezing during suspend/resume is best-effort. If the user has 500 ext4 filesystems mounted and 4 fail to freeze for whatever reason then we simply skip them. What we have now is already a big improvement and let's see how we fare with it before making our lives even harder (and uglier) than we have to. Signed-off-by: Christian Brauner <brauner@kernel.org> --- fs/super.c | 14 ++++++++++---- kernel/power/hibernate.c | 13 ++++++++++++- kernel/power/suspend.c | 8 ++++++++ 3 files changed, 30 insertions(+), 5 deletions(-)