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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 <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
This commit is contained in:
Christian Brauner 2023-08-22 13:32:50 +02:00
parent 2c18a63b76
commit 051178c366
No known key found for this signature in database
GPG Key ID: 91C61BC06578DCA2
1 changed files with 12 additions and 3 deletions
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15
fs/super.c
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@ -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);