From 051178c366bbc1bf8b4aba5ca5519d7da453c95f Mon Sep 17 00:00:00 2001 From: Christian Brauner Date: Tue, 22 Aug 2023 13:32:50 +0200 Subject: [PATCH] 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: Jan Kara Signed-off-by: Christian Brauner --- fs/super.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) diff --git a/fs/super.c b/fs/super.c index 2f604a6..a284052 100644 --- a/fs/super.c +++ b/fs/super.c @@ -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 @@ out: */ 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); -- 2.7.4