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authorLinus Torvalds <torvalds@linux-foundation.org>2023-08-29 11:59:37 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2023-08-29 11:59:37 -0700
commit468e28d4ac72869ed6c7cd7c7632008597949bd3 (patch)
tree313e91c62d910771feafdde4bcfbc09135f6742b /fs/super.c
parentbd6c11bc43c496cddfc6cf603b5d45365606dbd5 (diff)
parentdc3216b1416056b04712e53431f6e9aefdc83177 (diff)
Merge tag 'v6.6-vfs.super.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull superblock fixes from Christian Brauner: "Two follow-up fixes for the super work this cycle: - Move a misplaced lockep assertion before we potentially free the object containing the lock. - Ensure that filesystems which match superblocks in sget{_fc}() based on sb->s_fs_info are guaranteed to see a valid sb->s_fs_info as long as a superblock still appears on the filesystem type's superblock list. What we want as a proper solution for next cycle is to split sb->free_sb() out of sb->kill_sb() so that we can simply call kill_super_notify() after sb->kill_sb() but before sb->free_sb(). Currently, this is lumped together in sb->kill_sb()" * tag 'v6.6-vfs.super.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: super: ensure valid info super: move lockdep assert
Diffstat (limited to 'fs/super.c')
-rw-r--r--fs/super.c51
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);