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btrfs: do not background blkdev_put()

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At the end of unmount/dev-delete, if the device exclusive open is not
actually closed, then there might be a race with another program in
the userland who is trying to open the device in exclusive mode and
it may fail for eg:
      unmount /btrfs; fsck /dev/x
      btrfs dev del /dev/x /btrfs; fsck /dev/x
so here background blkdev_put() is not a choice

Signed-off-by: Anand Jain <Anand.Jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
This commit is contained in:
Anand Jain 2016-07-22 06:04:53 +08:00 committed by Chris Mason
parent 28b737f6ed
commit 1423881941
1 changed files with 19 additions and 8 deletions
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27
fs/btrfs/volumes.c
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@ -834,10 +834,6 @@ static void __free_device(struct work_struct *work)
struct btrfs_device *device;
device = container_of(work, struct btrfs_device, rcu_work);
if (device->bdev)
blkdev_put(device->bdev, device->mode);
rcu_string_free(device->name);
kfree(device);
}
@ -852,6 +848,17 @@ static void free_device(struct rcu_head *head)
schedule_work(&device->rcu_work);
}
static void btrfs_close_bdev(struct btrfs_device *device)
{
if (device->bdev && device->writeable) {
sync_blockdev(device->bdev);
invalidate_bdev(device->bdev);
}
if (device->bdev)
blkdev_put(device->bdev, device->mode);
}
static void btrfs_close_one_device(struct btrfs_device *device)
{
struct btrfs_fs_devices *fs_devices = device->fs_devices;
@ -870,10 +877,7 @@ static void btrfs_close_one_device(struct btrfs_device *device)
if (device->missing)
fs_devices->missing_devices--;
if (device->bdev && device->writeable) {
sync_blockdev(device->bdev);
invalidate_bdev(device->bdev);
}
btrfs_close_bdev(device);
new_device = btrfs_alloc_device(NULL, &device->devid,
device->uuid);
@ -1932,6 +1936,8 @@ int btrfs_rm_device(struct btrfs_root *root, char *device_path, u64 devid)
btrfs_sysfs_rm_device_link(root->fs_info->fs_devices, device);
}
btrfs_close_bdev(device);
call_rcu(&device->rcu, free_device);
num_devices = btrfs_super_num_devices(root->fs_info->super_copy) - 1;
@ -2025,6 +2031,9 @@ void btrfs_rm_dev_replace_free_srcdev(struct btrfs_fs_info *fs_info,
/* zero out the old super if it is writable */
btrfs_scratch_superblocks(srcdev->bdev, srcdev->name->str);
}
btrfs_close_bdev(srcdev);
call_rcu(&srcdev->rcu, free_device);
/*
@ -2080,6 +2089,8 @@ void btrfs_destroy_dev_replace_tgtdev(struct btrfs_fs_info *fs_info,
* the device_list_mutex lock.
*/
btrfs_scratch_superblocks(tgtdev->bdev, tgtdev->name->str);
btrfs_close_bdev(tgtdev);
call_rcu(&tgtdev->rcu, free_device);
}