[PATCH RFC 09/10] shmem: Implement shmem_destroy_super()

Kirill Tkhai
2018-08-07T15:39:37Z

Similar to xfs_fs_destroy_super() implement the method
for shmem.

shmem_unused_huge_count() just touches sb->s_fs_info.
After such the later freeing it will be safe for
unregister_shrinker() splitting (which is made in next
patch).

Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
---
mm/shmem.c | 8 ++++++++
1 file changed, 8 insertions(+)

diff --git a/mm/shmem.c b/mm/shmem.c
index 4829798869b6..35c65afefbc8 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -3427,6 +3427,12 @@ static void shmem_put_super(struct super_block *sb)

percpu_counter_destroy(&sbinfo->used_blocks);
mpol_put(sbinfo->mpol);
+}
+
+static void shmem_destroy_super(struct super_block *sb)
+{
+ struct shmem_sb_info *sbinfo = SHMEM_SB(sb);
+
kfree(sbinfo);
sb->s_fs_info = NULL;
}
@@ -3504,6 +3510,7 @@ int shmem_fill_super(struct super_block *sb, void *data, size_t data_size,

failed:
shmem_put_super(sb);
+ shmem_destroy_super(sb);
return err;
}

@@ -3630,6 +3637,7 @@ static const struct super_operations shmem_ops = {
.evict_inode = shmem_evict_inode,
.drop_inode = generic_delete_inode,
.put_super = shmem_put_super,
+ .destroy_super = shmem_destroy_super,
#ifdef CONFIG_TRANSPARENT_HUGE_PAGECACHE
.nr_cached_objects = shmem_unused_huge_count,
.free_cached_objects = shmem_unused_huge_scan,