Unverified Commit 051178c3 authored by Christian Brauner's avatar Christian Brauner
Browse files

super: use higher-level helper for {freeze,thaw} 



It's not necessary to use low-level locking helpers here. Use the
higher-level locking helpers and log if the superblock is dying. Since
the caller is assumed to already hold an active reference it isn't
possible to observe a dying superblock.

Suggested-by: default avatarJan Kara <jack@suse.cz>
Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parent 2c18a63b

fs/super.c

+12 −3
Original line number Diff line number Diff line
@@ -1873,8 +1873,13 @@ int freeze_super(struct super_block *sb) 
{

	int ret;



	/* Since the caller must already have an active reference... */

	atomic_inc(&sb->s_active);

	__super_lock_excl(sb);



	/* ...@sb definitely can't be dying. */

	if (!super_lock_excl(sb))

		WARN(1, "Dying superblock while freezing!");



	if (sb->s_writers.frozen != SB_UNFROZEN) {

		deactivate_locked_super(sb);

		return -EBUSY;
@@ -1896,7 +1901,10 @@ int freeze_super(struct super_block *sb) 
	/* Release s_umount to preserve sb_start_write -> s_umount ordering */

	super_unlock_excl(sb);

	sb_wait_write(sb, SB_FREEZE_WRITE);

	__super_lock_excl(sb);



	/* We're still holding an active reference. */

	if (!super_lock_excl(sb))

		WARN(1, "Dying superblock while freezing!");



	/* Now we go and block page faults... */

	sb->s_writers.frozen = SB_FREEZE_PAGEFAULT;
@@ -1979,7 +1987,8 @@ static int thaw_super_locked(struct super_block *sb) 
 */

int thaw_super(struct super_block *sb)

{

	__super_lock_excl(sb);

	if (!super_lock_excl(sb))

		WARN(1, "Dying superblock while thawing!");

	return thaw_super_locked(sb);

}

EXPORT_SYMBOL(thaw_super);