Fix btrfs_open_devices to deal with changes since the scan ioctls
Devices can change after the scan ioctls are done, and btrfs_open_devices
needs to be able to verify them as they are opened and used by the FS.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 43f74d1..501d23d 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -71,6 +71,7 @@
dev_list);
if (dev->bdev) {
close_bdev_excl(dev->bdev);
+ fs_devices->open_devices--;
}
list_del(&dev->dev_list);
kfree(dev->name);
@@ -174,9 +175,10 @@
list_for_each(cur, head) {
device = list_entry(cur, struct btrfs_device, dev_list);
if (!device->in_fs_metadata) {
-printk("getting rid of extra dev %s\n", device->name);
- if (device->bdev)
+ if (device->bdev) {
close_bdev_excl(device->bdev);
+ fs_devices->open_devices--;
+ }
list_del(&device->dev_list);
list_del(&device->dev_alloc_list);
fs_devices->num_devices--;
@@ -188,6 +190,7 @@
mutex_unlock(&uuid_mutex);
return 0;
}
+
int btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
{
struct list_head *head = &fs_devices->devices;
@@ -199,10 +202,12 @@
device = list_entry(cur, struct btrfs_device, dev_list);
if (device->bdev) {
close_bdev_excl(device->bdev);
+ fs_devices->open_devices--;
}
device->bdev = NULL;
device->in_fs_metadata = 0;
}
+ fs_devices->mounted = 0;
mutex_unlock(&uuid_mutex);
return 0;
}
@@ -214,9 +219,19 @@
struct list_head *head = &fs_devices->devices;
struct list_head *cur;
struct btrfs_device *device;
- int ret;
+ struct block_device *latest_bdev = NULL;
+ struct buffer_head *bh;
+ struct btrfs_super_block *disk_super;
+ u64 latest_devid = 0;
+ u64 latest_transid = 0;
+ u64 transid;
+ u64 devid;
+ int ret = 0;
mutex_lock(&uuid_mutex);
+ if (fs_devices->mounted)
+ goto out;
+
list_for_each(cur, head) {
device = list_entry(cur, struct btrfs_device, dev_list);
if (device->bdev)
@@ -229,21 +244,52 @@
if (IS_ERR(bdev)) {
printk("open %s failed\n", device->name);
- ret = PTR_ERR(bdev);
- goto fail;
+ goto error;
}
set_blocksize(bdev, 4096);
- if (device->devid == fs_devices->latest_devid)
- fs_devices->latest_bdev = bdev;
+
+ bh = __bread(bdev, BTRFS_SUPER_INFO_OFFSET / 4096, 4096);
+ if (!bh)
+ goto error_close;
+
+ disk_super = (struct btrfs_super_block *)bh->b_data;
+ if (strncmp((char *)(&disk_super->magic), BTRFS_MAGIC,
+ sizeof(disk_super->magic)))
+ goto error_brelse;
+
+ devid = le64_to_cpu(disk_super->dev_item.devid);
+ if (devid != device->devid)
+ goto error_brelse;
+
+ transid = btrfs_super_generation(disk_super);
+ if (transid > latest_transid) {
+ latest_devid = devid;
+ latest_transid = transid;
+ latest_bdev = bdev;
+ }
+
device->bdev = bdev;
device->in_fs_metadata = 0;
+ fs_devices->open_devices++;
+ continue;
+error_brelse:
+ brelse(bh);
+error_close:
+ close_bdev_excl(bdev);
+error:
+ continue;
}
+ if (fs_devices->open_devices == 0) {
+ ret = -EIO;
+ goto out;
+ }
+ fs_devices->mounted = 1;
+ fs_devices->latest_bdev = latest_bdev;
+ fs_devices->latest_devid = latest_devid;
+ fs_devices->latest_trans = latest_transid;
+out:
mutex_unlock(&uuid_mutex);
- return 0;
-fail:
- mutex_unlock(&uuid_mutex);
- btrfs_close_devices(fs_devices);
return ret;
}
@@ -828,6 +874,7 @@
if (device->bdev) {
/* one close for the device struct or super_block */
close_bdev_excl(device->bdev);
+ root->fs_info->fs_devices->open_devices--;
}
if (bdev) {
/* one close for us */
@@ -914,6 +961,7 @@
list_add(&device->dev_alloc_list,
&root->fs_info->fs_devices->alloc_list);
root->fs_info->fs_devices->num_devices++;
+ root->fs_info->fs_devices->open_devices++;
out:
btrfs_end_transaction(trans, root);
mutex_unlock(&root->fs_info->fs_mutex);