From 12a6caf273240ae42842de8cc05feaa86e582d61 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Tue, 19 Jul 2022 11:18:23 +0200 Subject: [PATCH] md: only delete entries from all_mddevs when the disk is freed This ensures device names don't get prematurely reused. Instead add a deleted flag to skip already deleted devices in mddev_get and other places that only want to see live mddevs. Reported-by: Logan Gunthorpe Signed-off-by: Christoph Hellwig Reviewed-by: Hannes Reinecke Reviewed-by: Logan Gunthorpe Signed-off-by: Song Liu Signed-off-by: Jens Axboe --- drivers/md/md.c | 56 ++++++++++++++++++++++++++++++++++++++------------------ drivers/md/md.h | 2 ++ 2 files changed, 40 insertions(+), 18 deletions(-) diff --git a/drivers/md/md.c b/drivers/md/md.c index 709df90..2e9ed44 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -625,6 +625,10 @@ EXPORT_SYMBOL(md_flush_request); static inline struct mddev *mddev_get(struct mddev *mddev) { + lockdep_assert_held(&all_mddevs_lock); + + if (test_bit(MD_DELETED, &mddev->flags)) + return NULL; atomic_inc(&mddev->active); return mddev; } @@ -639,7 +643,7 @@ static void mddev_put(struct mddev *mddev) mddev->ctime == 0 && !mddev->hold_active) { /* Array is not configured at all, and not held active, * so destroy it */ - list_del_init(&mddev->all_mddevs); + set_bit(MD_DELETED, &mddev->flags); /* * Call queue_work inside the spinlock so that @@ -719,8 +723,8 @@ static struct mddev *mddev_find(dev_t unit) spin_lock(&all_mddevs_lock); mddev = mddev_find_locked(unit); - if (mddev) - mddev_get(mddev); + if (mddev && !mddev_get(mddev)) + mddev = NULL; spin_unlock(&all_mddevs_lock); return mddev; @@ -3338,6 +3342,8 @@ static bool md_rdev_overlaps(struct md_rdev *rdev) spin_lock(&all_mddevs_lock); list_for_each_entry(mddev, &all_mddevs, all_mddevs) { + if (test_bit(MD_DELETED, &mddev->flags)) + continue; rdev_for_each(rdev2, mddev) { if (rdev != rdev2 && rdev->bdev == rdev2->bdev && md_rdevs_overlap(rdev, rdev2)) { @@ -5525,11 +5531,10 @@ md_attr_show(struct kobject *kobj, struct attribute *attr, char *page) if (!entry->show) return -EIO; spin_lock(&all_mddevs_lock); - if (list_empty(&mddev->all_mddevs)) { + if (!mddev_get(mddev)) { spin_unlock(&all_mddevs_lock); return -EBUSY; } - mddev_get(mddev); spin_unlock(&all_mddevs_lock); rv = entry->show(mddev, page); @@ -5550,11 +5555,10 @@ md_attr_store(struct kobject *kobj, struct attribute *attr, if (!capable(CAP_SYS_ADMIN)) return -EACCES; spin_lock(&all_mddevs_lock); - if (list_empty(&mddev->all_mddevs)) { + if (!mddev_get(mddev)) { spin_unlock(&all_mddevs_lock); return -EBUSY; } - mddev_get(mddev); spin_unlock(&all_mddevs_lock); rv = entry->store(mddev, page, length); mddev_put(mddev); @@ -7849,7 +7853,7 @@ static void md_free_disk(struct gendisk *disk) bioset_exit(&mddev->bio_set); bioset_exit(&mddev->sync_set); - kfree(mddev); + mddev_free(mddev); } const struct block_device_operations md_fops = @@ -8171,6 +8175,8 @@ static void *md_seq_start(struct seq_file *seq, loff_t *pos) if (!l--) { mddev = list_entry(tmp, struct mddev, all_mddevs); mddev_get(mddev); + if (!mddev_get(mddev)) + continue; spin_unlock(&all_mddevs_lock); return mddev; } @@ -8184,25 +8190,35 @@ static void *md_seq_next(struct seq_file *seq, void *v, loff_t *pos) { struct list_head *tmp; struct mddev *next_mddev, *mddev = v; + struct mddev *to_put = NULL; ++*pos; if (v == (void*)2) return NULL; spin_lock(&all_mddevs_lock); - if (v == (void*)1) + if (v == (void*)1) { tmp = all_mddevs.next; - else + } else { + to_put = mddev; tmp = mddev->all_mddevs.next; - if (tmp != &all_mddevs) - next_mddev = mddev_get(list_entry(tmp,struct mddev,all_mddevs)); - else { - next_mddev = (void*)2; - *pos = 0x10000; } + + for (;;) { + if (tmp == &all_mddevs) { + next_mddev = (void*)2; + *pos = 0x10000; + break; + } + next_mddev = list_entry(tmp, struct mddev, all_mddevs); + if (mddev_get(next_mddev)) + break; + mddev = next_mddev; + tmp = mddev->all_mddevs.next; + }; spin_unlock(&all_mddevs_lock); - if (v != (void*)1) + if (to_put) mddev_put(mddev); return next_mddev; @@ -8766,6 +8782,8 @@ void md_do_sync(struct md_thread *thread) goto skip; spin_lock(&all_mddevs_lock); list_for_each_entry(mddev2, &all_mddevs, all_mddevs) { + if (test_bit(MD_DELETED, &mddev2->flags)) + continue; if (mddev2 == mddev) continue; if (!mddev->parallel_resync @@ -9568,7 +9586,8 @@ static int md_notify_reboot(struct notifier_block *this, spin_lock(&all_mddevs_lock); list_for_each_entry_safe(mddev, n, &all_mddevs, all_mddevs) { - mddev_get(mddev); + if (!mddev_get(mddev)) + continue; spin_unlock(&all_mddevs_lock); if (mddev_trylock(mddev)) { if (mddev->pers) @@ -9923,7 +9942,8 @@ static __exit void md_exit(void) spin_lock(&all_mddevs_lock); list_for_each_entry_safe(mddev, n, &all_mddevs, all_mddevs) { - mddev_get(mddev); + if (!mddev_get(mddev)) + continue; spin_unlock(&all_mddevs_lock); export_array(mddev); mddev->ctime = 0; diff --git a/drivers/md/md.h b/drivers/md/md.h index 861088b..f6ab73c 100644 --- a/drivers/md/md.h +++ b/drivers/md/md.h @@ -254,6 +254,7 @@ struct md_cluster_info; * @MD_NOT_READY: do_md_run() is active, so 'array_state', ust not report that * array is ready yet. * @MD_BROKEN: This is used to stop writes and mark array as failed. + * @MD_DELETED: This device is being deleted * * change UNSUPPORTED_MDDEV_FLAGS for each array type if new flag is added */ @@ -270,6 +271,7 @@ enum mddev_flags { MD_UPDATING_SB, MD_NOT_READY, MD_BROKEN, + MD_DELETED, }; enum mddev_sb_flags { -- 2.7.4