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fs: stop using get_super in fs_mark_dead 

fs_mark_dead currently uses get_super to find the superblock for the
block device that is going away.  This means it is limited to the
main device stored in sb->s_dev, leading to a lot of code duplication
for file systems that can use multiple block devices.

Now that the holder for all block devices used by file systems is set
to the super_block, we can instead look at that holder and then check
if the file system is born and active, so do that instead.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Message-Id: <20230802154131.2221419-8-hch@lst.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
This commit is contained in:
Christoph Hellwig 2023-08-02 17:41:26 +02:00 committed by Christian Brauner
parent 2ea6f68932
commit 9c09a7cf62
1 changed files with 26 additions and 4 deletions
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30
fs/super.c
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@ -1209,17 +1209,39 @@ int get_tree_keyed(struct fs_context *fc,
EXPORT_SYMBOL(get_tree_keyed);
#ifdef CONFIG_BLOCK
/*
* Lock a super block that the callers holds a reference to.
*
* The caller needs to ensure that the super_block isn't being freed while
* calling this function, e.g. by holding a lock over the call to this function
* and the place that clears the pointer to the superblock used by this function
* before freeing the superblock.
*/
static bool lock_active_super(struct super_block *sb)
{
down_read(&sb->s_umount);
if (!sb->s_root ||
(sb->s_flags & (SB_ACTIVE | SB_BORN)) != (SB_ACTIVE | SB_BORN)) {
up_read(&sb->s_umount);
return false;
}
return true;
}
static void fs_mark_dead(struct block_device *bdev)
{
struct super_block *sb;
struct super_block *sb = bdev->bd_holder;
sb = get_super(bdev);
if (!sb)
/* bd_holder_lock ensures that the sb isn't freed */
lockdep_assert_held(&bdev->bd_holder_lock);
if (!lock_active_super(sb))
return;
if (sb->s_op->shutdown)
sb->s_op->shutdown(sb);
drop_super(sb);
up_read(&sb->s_umount);
}
static const struct blk_holder_ops fs_holder_ops = {