[RFC 4/5] ext4: add fs freezing support on suspend/hibernation

[Luis R. Rodriguez]

This also removes the superflous freezer calls as they are no longer
needed. We need to avoid sync call on thaw as otherwise we end up with
a stall on bio_submit().

Signed-off-by: Luis R. Rodriguez <mcg...@kernel.org>
---
 fs/ext4/super.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 3cc5635d00cc..03d3bbd27dae 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -119,7 +119,8 @@ static struct file_system_type ext2_fs_type = {
        .name           = "ext2",
        .mount          = ext4_mount,
        .kill_sb        = kill_block_super,
-       .fs_flags       = FS_REQUIRES_DEV,
+       .fs_flags       = FS_REQUIRES_DEV |
+                         FS_FREEZE_ON_SUSPEND,
 };
 MODULE_ALIAS_FS("ext2");
 MODULE_ALIAS("ext2");
@@ -134,7 +135,8 @@ static struct file_system_type ext3_fs_type = {
        .name           = "ext3",
        .mount          = ext4_mount,
        .kill_sb        = kill_block_super,
-       .fs_flags       = FS_REQUIRES_DEV,
+       .fs_flags       = FS_REQUIRES_DEV |
+                         FS_FREEZE_ON_SUSPEND,
 };
 MODULE_ALIAS_FS("ext3");
 MODULE_ALIAS("ext3");
@@ -2979,8 +2981,6 @@ static int ext4_lazyinit_thread(void *arg)
                }
                mutex_unlock(&eli->li_list_mtx);
 
-               try_to_freeze();
-
                cur = jiffies;
                if ((time_after_eq(cur, next_wakeup)) ||
                    (MAX_JIFFY_OFFSET == next_wakeup)) {
@@ -4926,7 +4926,7 @@ static int ext4_unfreeze(struct super_block *sb)
                ext4_set_feature_journal_needs_recovery(sb);
        }
 
-       ext4_commit_super(sb, 1);
+       ext4_commit_super(sb, 0);
        return 0;
 }
 
@@ -5771,7 +5771,8 @@ static struct file_system_type ext4_fs_type = {
        .name           = "ext4",
        .mount          = ext4_mount,
        .kill_sb        = kill_block_super,
-       .fs_flags       = FS_REQUIRES_DEV,
+       .fs_flags       = FS_REQUIRES_DEV |
+                         FS_FREEZE_ON_SUSPEND,
 };
 MODULE_ALIAS_FS("ext4");
 
-- 
2.14.0