The new function btrfs_find_device_missing_or_by_path() will be
used for the device replace procedure. This function itself calls
the second new function btrfs_find_device_by_path().
Unfortunately, it is not possible to currently make the rest of the
code use these functions as well, since all functions that look
similar at first view are all a little bit different in what they
are doing. But in the future, new code could benefit from these
two new functions, and currently, device replace uses them.
Signed-off-by: Stefan Behrens <sbehrens@xxxxxxxxxxxxxxxx>
---
fs/btrfs/volumes.c | 74 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
fs/btrfs/volumes.h | 5 ++++
2 files changed, 79 insertions(+)
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index eeed97d..bcd3097 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -1512,6 +1512,80 @@ error_undo:
goto error_brelse;
}
+int btrfs_find_device_by_path(struct btrfs_root *root, char *device_path,
+ struct btrfs_device **device)
+{
+ int ret = 0;
+ struct btrfs_super_block *disk_super;
+ u64 devid;
+ u8 *dev_uuid;
+ struct block_device *bdev;
+ struct buffer_head *bh = NULL;
+
+ *device = NULL;
+ mutex_lock(&uuid_mutex);
+ bdev = blkdev_get_by_path(device_path, FMODE_READ,
+ root->fs_info->bdev_holder);
+ if (IS_ERR(bdev)) {
+ ret = PTR_ERR(bdev);
+ bdev = NULL;
+ goto out;
+ }
+
+ set_blocksize(bdev, 4096);
+ invalidate_bdev(bdev);
+ bh = btrfs_read_dev_super(bdev);
+ if (!bh) {
+ ret = -EINVAL;
+ goto out;
+ }
+ disk_super = (struct btrfs_super_block *)bh->b_data;
+ devid = btrfs_stack_device_id(&disk_super->dev_item);
+ dev_uuid = disk_super->dev_item.uuid;
+ *device = btrfs_find_device(root, devid, dev_uuid,
+ disk_super->fsid);
+ brelse(bh);
+ if (!*device)
+ ret = -ENOENT;
+out:
+ mutex_unlock(&uuid_mutex);
+ if (bdev)
+ blkdev_put(bdev, FMODE_READ);
+ return ret;
+}
+
+int btrfs_find_device_missing_or_by_path(struct btrfs_root *root,
+ char *device_path,
+ struct btrfs_device **device)
+{
+ *device = NULL;
+ if (strcmp(device_path, "missing") == 0) {
+ struct list_head *devices;
+ struct btrfs_device *tmp;
+
+ devices = &root->fs_info->fs_devices->devices;
+ /*
+ * It is safe to read the devices since the volume_mutex
+ * is held by the caller.
+ */
+ list_for_each_entry(tmp, devices, dev_list) {
+ if (tmp->in_fs_metadata && !tmp->bdev) {
+ *device = tmp;
+ break;
+ }
+ }
+
+ if (!*device) {
+ pr_err("btrfs: no missing device found\n");
+ return -ENOENT;
+ }
+
+ return 0;
+ } else {
+ return btrfs_find_device_by_path(root, device_path, device);
+ }
+}
+
/*
* does all the dirty work required for changing file system's UUID.
*/
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index 1789cda..657bb12 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -268,6 +268,11 @@ int btrfs_scan_one_device(const char *path, fmode_t flags, void *holder,
struct btrfs_fs_devices **fs_devices_ret);
int btrfs_close_devices(struct btrfs_fs_devices *fs_devices);
void btrfs_close_extra_devices(struct btrfs_fs_devices *fs_devices);
+int btrfs_find_device_missing_or_by_path(struct btrfs_root *root,
+ char *device_path,
+ struct btrfs_device **device);
+int btrfs_find_device_by_path(struct btrfs_root *root, char *device_path,
+ struct btrfs_device **device);
int btrfs_add_device(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_device *device);
--
1.8.0
--
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