diff options
| -rw-r--r-- | fs/super.c | 51 |
1 files changed, 31 insertions, 20 deletions
diff --git a/fs/super.c b/fs/super.c index 692654c2af36..1db67a6e138c 100644 --- a/fs/super.c +++ b/fs/super.c @@ -434,6 +434,33 @@ void put_super(struct super_block *sb) spin_unlock(&sb_lock); } +static void kill_super_notify(struct super_block *sb) +{ + lockdep_assert_not_held(&sb->s_umount); + + /* already notified earlier */ + if (sb->s_flags & SB_DEAD) + return; + + /* + * Remove it from @fs_supers so it isn't found by new + * sget{_fc}() walkers anymore. Any concurrent mounter still + * managing to grab a temporary reference is guaranteed to + * already see SB_DYING and will wait until we notify them about + * SB_DEAD. + */ + spin_lock(&sb_lock); + hlist_del_init(&sb->s_instances); + spin_unlock(&sb_lock); + + /* + * Let concurrent mounts know that this thing is really dead. + * We don't need @sb->s_umount here as every concurrent caller + * will see SB_DYING and either discard the superblock or wait + * for SB_DEAD. + */ + super_wake(sb, SB_DEAD); +} /** * deactivate_locked_super - drop an active reference to superblock @@ -453,6 +480,8 @@ void deactivate_locked_super(struct super_block *s) unregister_shrinker(&s->s_shrink); fs->kill_sb(s); + kill_super_notify(s); + /* * Since list_lru_destroy() may sleep, we cannot call it from * put_super(), where we hold the sb_lock. Therefore we destroy @@ -461,25 +490,6 @@ void deactivate_locked_super(struct super_block *s) list_lru_destroy(&s->s_dentry_lru); list_lru_destroy(&s->s_inode_lru); - /* - * Remove it from @fs_supers so it isn't found by new - * sget{_fc}() walkers anymore. Any concurrent mounter still - * managing to grab a temporary reference is guaranteed to - * already see SB_DYING and will wait until we notify them about - * SB_DEAD. - */ - spin_lock(&sb_lock); - hlist_del_init(&s->s_instances); - spin_unlock(&sb_lock); - - /* - * Let concurrent mounts know that this thing is really dead. - * We don't need @sb->s_umount here as every concurrent caller - * will see SB_DYING and either discard the superblock or wait - * for SB_DEAD. - */ - super_wake(s, SB_DEAD); - put_filesystem(fs); put_super(s); } else { @@ -570,8 +580,8 @@ static bool grab_super_dead(struct super_block *sb) return true; } wait_var_event(&sb->s_flags, wait_dead(sb)); - put_super(sb); lockdep_assert_not_held(&sb->s_umount); + put_super(sb); return false; } @@ -1278,6 +1288,7 @@ void kill_anon_super(struct super_block *sb) { dev_t dev = sb->s_dev; generic_shutdown_super(sb); + kill_super_notify(sb); free_anon_bdev(dev); } EXPORT_SYMBOL(kill_anon_super); |