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Message-ID: <20250329-work-freeze-v2-6-a47af37ecc3d@kernel.org>
Date: Sat, 29 Mar 2025 09:42:19 +0100
From: Christian Brauner <brauner@...nel.org>
To: linux-fsdevel@...r.kernel.org,
jack@...e.cz
Cc: Christian Brauner <brauner@...nel.org>,
linux-kernel@...r.kernel.org,
James Bottomley <James.Bottomley@...senpartnership.com>,
mcgrof@...nel.org,
hch@...radead.org,
david@...morbit.com,
rafael@...nel.org,
djwong@...nel.org,
pavel@...nel.org,
peterz@...radead.org,
mingo@...hat.com,
will@...nel.org,
boqun.feng@...il.com
Subject: [PATCH v2 6/6] super: add filesystem freezing helpers for suspend and hibernate
Allow the power subsystem to support filesystem freeze for
suspend and hibernate.
Signed-off-by: Christian Brauner <brauner@...nel.org>
---
fs/super.c | 55 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
include/linux/fs.h | 2 ++
2 files changed, 57 insertions(+)
diff --git a/fs/super.c b/fs/super.c
index 666a2a16df87..4364b763e91f 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -1176,6 +1176,61 @@ void emergency_thaw_all(void)
}
}
+static inline bool get_active_super(struct super_block *sb)
+{
+ bool active;
+
+ if (super_lock_excl(sb)) {
+ active = atomic_inc_not_zero(&sb->s_active);
+ super_unlock_excl(sb);
+ }
+ return active;
+}
+
+static void filesystems_freeze_callback(struct super_block *sb, void *unused)
+{
+ if (!sb->s_op->freeze_fs && !sb->s_op->freeze_super)
+ return;
+
+ if (!get_active_super(sb))
+ return;
+
+ if (sb->s_op->freeze_super)
+ sb->s_op->freeze_super(sb, FREEZE_MAY_NEST | FREEZE_HOLDER_KERNEL);
+ else
+ freeze_super(sb, FREEZE_MAY_NEST | FREEZE_HOLDER_KERNEL);
+
+ deactivate_super(sb);
+}
+
+void filesystems_freeze(bool hibernate)
+{
+ __iterate_supers(filesystems_freeze_callback, NULL,
+ SUPER_ITER_UNLOCKED | SUPER_ITER_REVERSE);
+}
+
+static void filesystems_thaw_callback(struct super_block *sb, void *unused)
+{
+ if (!sb->s_op->freeze_fs && !sb->s_op->freeze_super)
+ return;
+
+ if (!get_active_super(sb))
+ return;
+
+ if (sb->s_op->thaw_super)
+ sb->s_op->thaw_super(sb, FREEZE_MAY_NEST | FREEZE_HOLDER_KERNEL);
+ else
+ thaw_super(sb, FREEZE_MAY_NEST | FREEZE_HOLDER_KERNEL);
+
+ deactivate_super(sb);
+}
+
+void filesystems_thaw(bool hibernate)
+{
+ __iterate_supers(filesystems_thaw_callback, NULL,
+ SUPER_ITER_UNLOCKED | SUPER_ITER_REVERSE);
+}
+
static DEFINE_IDA(unnamed_dev_ida);
/**
diff --git a/include/linux/fs.h b/include/linux/fs.h
index c475fa874055..29bd28491eff 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -3518,6 +3518,8 @@ extern void drop_super_exclusive(struct super_block *sb);
extern void iterate_supers(void (*f)(struct super_block *, void *), void *arg);
extern void iterate_supers_type(struct file_system_type *,
void (*)(struct super_block *, void *), void *);
+void filesystems_freeze(bool hibernate);
+void filesystems_thaw(bool hibernate);
extern int dcache_dir_open(struct inode *, struct file *);
extern int dcache_dir_close(struct inode *, struct file *);
--
2.47.2
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