diff options
| author | NeilBrown <neilb@suse.de> | 2008-07-21 17:05:25 +1000 |
|---|---|---|
| committer | NeilBrown <neilb@suse.de> | 2008-07-21 17:05:25 +1000 |
| commit | f2ea68cf42aafdd93393b6b8b20fc3c2b5f4390c (patch) | |
| tree | 00b025b91898ff32dba742b5075dd290fec4dc91 | |
| parent | d6e2215052810678bc9782fd980b52706fc71f50 (diff) | |
| download | linux-f2ea68cf42aafdd93393b6b8b20fc3c2b5f4390c.tar.bz2 | |
md: only count actual openers as access which prevent a 'stop'
Open isn't the only thing that increments ->active. e.g. reading
/proc/mdstat will increment it briefly. So to avoid false positives
in testing for concurrent access, introduce a new counter that counts
just the number of times the md device it open.
Signed-off-by: NeilBrown <neilb@suse.de>
| -rw-r--r-- | drivers/md/md.c | 9 | ||||
| -rw-r--r-- | include/linux/raid/md_k.h | 3 |
2 files changed, 8 insertions, 4 deletions
diff --git a/drivers/md/md.c b/drivers/md/md.c index 4bfbc1982cda..450f30b6edf9 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -273,6 +273,7 @@ static mddev_t * mddev_find(dev_t unit) INIT_LIST_HEAD(&new->all_mddevs); init_timer(&new->safemode_timer); atomic_set(&new->active, 1); + atomic_set(&new->openers, 0); spin_lock_init(&new->write_lock); init_waitqueue_head(&new->sb_wait); init_waitqueue_head(&new->recovery_wait); @@ -2695,14 +2696,14 @@ array_state_store(mddev_t *mddev, const char *buf, size_t len) break; case clear: /* stopping an active array */ - if (atomic_read(&mddev->active) > 1) + if (atomic_read(&mddev->openers) > 0) return -EBUSY; err = do_md_stop(mddev, 0, 0); break; case inactive: /* stopping an active array */ if (mddev->pers) { - if (atomic_read(&mddev->active) > 1) + if (atomic_read(&mddev->openers) > 0) return -EBUSY; err = do_md_stop(mddev, 2, 0); } else @@ -3816,7 +3817,7 @@ static int do_md_stop(mddev_t * mddev, int mode, int is_open) int err = 0; struct gendisk *disk = mddev->gendisk; - if (atomic_read(&mddev->active) > 1 + is_open) { + if (atomic_read(&mddev->openers) > is_open) { printk("md: %s still in use.\n",mdname(mddev)); return -EBUSY; } @@ -5014,6 +5015,7 @@ static int md_open(struct inode *inode, struct file *file) err = 0; mddev_get(mddev); + atomic_inc(&mddev->openers); mddev_unlock(mddev); check_disk_change(inode->i_bdev); @@ -5026,6 +5028,7 @@ static int md_release(struct inode *inode, struct file * file) mddev_t *mddev = inode->i_bdev->bd_disk->private_data; BUG_ON(!mddev); + atomic_dec(&mddev->openers); mddev_put(mddev); return 0; diff --git a/include/linux/raid/md_k.h b/include/linux/raid/md_k.h index 6f72b47ae41c..4bef4791d80d 100644 --- a/include/linux/raid/md_k.h +++ b/include/linux/raid/md_k.h @@ -215,7 +215,8 @@ struct mddev_s int in_sync; /* know to not need resync */ struct mutex reconfig_mutex; - atomic_t active; + atomic_t active; /* general refcount */ + atomic_t openers; /* number of active opens */ int changed; /* true if we might need to reread partition info */ int degraded; /* whether md should consider |