[PATCH v6 14/24] erofs: introduce superblock registration

Gao Xiang
2019-08-02T12:56:11Z

In order to introducing shrinker solution for erofs,
let's manage all mounted erofs instances at first.

Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
fs/erofs/Makefile | 2 +-
fs/erofs/internal.h | 13 +++++++++++++
fs/erofs/super.c | 9 +++++++++
fs/erofs/utils.c | 32 ++++++++++++++++++++++++++++++++
4 files changed, 55 insertions(+), 1 deletion(-)
create mode 100644 fs/erofs/utils.c

diff --git a/fs/erofs/Makefile b/fs/erofs/Makefile
index 481a966caf06..930770be124f 100644
--- a/fs/erofs/Makefile
+++ b/fs/erofs/Makefile
@@ -5,7 +5,7 @@ EROFS_VERSION = "1.0"
ccflags-y += -DEROFS_VERSION=\"$(EROFS_VERSION)\"

obj-$(CONFIG_EROFS_FS) += erofs.o
-erofs-objs := super.o inode.o data.o namei.o dir.o
+erofs-objs := super.o inode.o data.o namei.o dir.o utils.o
erofs-$(CONFIG_EROFS_FS_XATTR) += xattr.o
erofs-$(CONFIG_EROFS_FS_ZIP) += zmap.o

diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
index d3a703017233..082fa4727c80 100644
--- a/fs/erofs/internal.h
+++ b/fs/erofs/internal.h
@@ -61,6 +61,10 @@ typedef u64 erofs_off_t;
typedef u32 erofs_blk_t;

struct erofs_sb_info {
+#ifdef CONFIG_EROFS_FS_ZIP
+ /* list for all registered superblocks, mainly for shrinker */
+ struct list_head list;
+#endif /* CONFIG_EROFS_FS_ZIP */
u32 blocks;
u32 meta_blkaddr;
#ifdef CONFIG_EROFS_FS_XATTR
@@ -401,5 +405,14 @@ int erofs_namei(struct inode *dir, struct qstr *name,
/* dir.c */
extern const struct file_operations erofs_dir_fops;

+/* utils.c */
+#ifdef CONFIG_EROFS_FS_ZIP
+void erofs_shrinker_register(struct super_block *sb);
+void erofs_shrinker_unregister(struct super_block *sb);
+#else
+static inline void erofs_shrinker_register(struct super_block *sb) {}
+static inline void erofs_shrinker_unregister(struct super_block *sb) {}
+#endif /* !CONFIG_EROFS_FS_ZIP */
+
#endif /* __EROFS_INTERNAL_H */

diff --git a/fs/erofs/super.c b/fs/erofs/super.c
index 561ae6f7fe13..2eca3b25db75 100644
--- a/fs/erofs/super.c
+++ b/fs/erofs/super.c
@@ -354,6 +354,8 @@ static int erofs_fill_super(struct super_block *sb, void *data, int silent)
if (unlikely(!sb->s_root))
return -ENOMEM;

+ erofs_shrinker_register(sb);
+
if (!silent)
infoln("mounted on %s with opts: %s.", sb->s_id, (char *)data);
return 0;
@@ -385,6 +387,12 @@ static void erofs_kill_sb(struct super_block *sb)
sb->s_fs_info = NULL;
}

+/* called when ->s_root is non-NULL */
+static void erofs_put_super(struct super_block *sb)
+{
+ erofs_shrinker_unregister(sb);
+}
+
static struct file_system_type erofs_fs_type = {
.owner = THIS_MODULE,
.name = "erofs",
@@ -496,6 +504,7 @@ static int erofs_remount(struct super_block *sb, int *flags, char *data)
}

const struct super_operations erofs_sops = {
+ .put_super = erofs_put_super,
.alloc_inode = alloc_inode,
.free_inode = free_inode,
.statfs = erofs_statfs,
diff --git a/fs/erofs/utils.c b/fs/erofs/utils.c
new file mode 100644
index 000000000000..791b2df1f761
--- /dev/null
+++ b/fs/erofs/utils.c
@@ -0,0 +1,32 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * linux/fs/erofs/utils.c
+ *
+ * Copyright (C) 2018 HUAWEI, Inc.
+ * http://www.huawei.com/
+ * Created by Gao Xiang <gaoxiang25@huawei.com>
+ */
+#include "internal.h"
+
+#ifdef CONFIG_EROFS_FS_ZIP
+/* protects the mounted 'erofs_sb_list' */
+static DEFINE_SPINLOCK(erofs_sb_list_lock);
+static LIST_HEAD(erofs_sb_list);
+
+void erofs_shrinker_register(struct super_block *sb)
+{
+ struct erofs_sb_info *sbi = EROFS_SB(sb);
+
+ spin_lock(&erofs_sb_list_lock);
+ list_add(&sbi->list, &erofs_sb_list);
+ spin_unlock(&erofs_sb_list_lock);
+}
+
+void erofs_shrinker_unregister(struct super_block *sb)
+{
+ spin_lock(&erofs_sb_list_lock);
+ list_del(&EROFS_SB(sb)->list);
+ spin_unlock(&erofs_sb_list_lock);
+}
+#endif /* !CONFIG_EROFS_FS_ZIP */
+
--
2.17.1