Unverified Commit 29924765 authored by Christian Brauner's avatar Christian Brauner
Browse files

super: use a common iterator (Part 1) 

Use a common iterator for all callbacks.

Link: https://lore.kernel.org/r/20250329-work-freeze-v2-4-a47af37ecc3d@kernel.org


Reviewed-by: default avatarJan Kara <jack@suse.cz>
Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parent 6920e338

fs/super.c

+13 −54
Original line number Diff line number Diff line
@@ -887,37 +887,7 @@ void drop_super_exclusive(struct super_block *sb) 
}

EXPORT_SYMBOL(drop_super_exclusive);



static void __iterate_supers(void (*f)(struct super_block *))

{

	struct super_block *sb, *p = NULL;



	spin_lock(&sb_lock);

	list_for_each_entry(sb, &super_blocks, s_list) {

		if (super_flags(sb, SB_DYING))

			continue;

		sb->s_count++;

		spin_unlock(&sb_lock);



		f(sb);



		spin_lock(&sb_lock);

		if (p)

			__put_super(p);

		p = sb;

	}

	if (p)

		__put_super(p);

	spin_unlock(&sb_lock);

}

/**

 *	iterate_supers - call function for all active superblocks

 *	@f: function to call

 *	@arg: argument to pass to it

 *

 *	Scans the superblock list and calls given function, passing it

 *	locked superblock and given argument.

 */

void iterate_supers(void (*f)(struct super_block *, void *), void *arg)

void __iterate_supers(void (*f)(struct super_block *, void *), void *arg, bool excl)

{

	struct super_block *sb, *p = NULL;
@@ -927,14 +897,13 @@ void iterate_supers(void (*f)(struct super_block *, void *), void *arg) 


		if (super_flags(sb, SB_DYING))

			continue;



		sb->s_count++;

		spin_unlock(&sb_lock);



		locked = super_lock_shared(sb);

		locked = super_lock(sb, excl);

		if (locked) {

			f(sb, arg);

			super_unlock_shared(sb);

			super_unlock(sb, excl);

		}



		spin_lock(&sb_lock);
@@ -1111,11 +1080,9 @@ int reconfigure_super(struct fs_context *fc) 
	return retval;

}



static void do_emergency_remount_callback(struct super_block *sb)

static void do_emergency_remount_callback(struct super_block *sb, void *unused)

{

	bool locked = super_lock_excl(sb);



	if (locked && sb->s_root && sb->s_bdev && !sb_rdonly(sb)) {

	if (sb->s_bdev && !sb_rdonly(sb)) {

		struct fs_context *fc;



		fc = fs_context_for_reconfigure(sb->s_root,
@@ -1126,13 +1093,11 @@ static void do_emergency_remount_callback(struct super_block *sb) 
			put_fs_context(fc);

		}

	}

	if (locked)

		super_unlock_excl(sb);

}



static void do_emergency_remount(struct work_struct *work)

{

	__iterate_supers(do_emergency_remount_callback);

	__iterate_supers(do_emergency_remount_callback, NULL, true);

	kfree(work);

	printk("Emergency Remount complete\n");

}
@@ -1148,24 +1113,18 @@ void emergency_remount(void) 
	}

}



static void do_thaw_all_callback(struct super_block *sb)

static void do_thaw_all_callback(struct super_block *sb, void *unused)

{

	bool locked = super_lock_excl(sb);



	if (locked && sb->s_root) {

	if (IS_ENABLED(CONFIG_BLOCK))

		while (sb->s_bdev && !bdev_thaw(sb->s_bdev))

			pr_warn("Emergency Thaw on %pg\n", sb->s_bdev);

	thaw_super_locked(sb, FREEZE_HOLDER_USERSPACE);

	return;

}

	if (locked)

		super_unlock_excl(sb);

}



static void do_thaw_all(struct work_struct *work)

{

	__iterate_supers(do_thaw_all_callback);

	__iterate_supers(do_thaw_all_callback, NULL, true);

	kfree(work);

	printk(KERN_WARNING "Emergency Thaw complete\n");

}

include/linux/fs.h

+5 −1
Original line number Diff line number Diff line
@@ -3515,7 +3515,11 @@ extern void put_filesystem(struct file_system_type *fs); 
extern struct file_system_type *get_fs_type(const char *name);

extern void drop_super(struct super_block *sb);

extern void drop_super_exclusive(struct super_block *sb);

extern void iterate_supers(void (*)(struct super_block *, void *), void *);

void __iterate_supers(void (*f)(struct super_block *, void *), void *arg, bool excl);

static inline void iterate_supers(void (*f)(struct super_block *, void *), void *arg)

{

	__iterate_supers(f, arg, false);

}

extern void iterate_supers_type(struct file_system_type *,

			        void (*)(struct super_block *, void *), void *);