btrfs-rescue: add page (#6963)

pages/linux/btrfs-rescue.md

@@ -0,0 +1,24 @@
+# btrfs rescue
+
+> Try to recover a damaged btrfs filesystem.
+> More information: <https://btrfs.wiki.kernel.org/index.php/Manpage/btrfs-rescue>.
+
+- Rebuild the filesystem metadata tree (very slow):
+
+`sudo btrfs rescue chunk-recover {{path/to/partition}}`
+
+- Fix device size alignment related problems (e.g. unable to mount the filesystem with super total bytes mismatch):
+
+`sudo btrfs rescue fix-device-size {{path/to/partition}}`
+
+- Recover a corrupted superblock from correct copies (recover the root of filesystem tree):
+
+`sudo btrfs rescue super-recover {{path/to/partition}}`
+
+- Recover from an interrupted transactions (fixes log replay problems):
+
+`sudo btrfs rescue zero-log {{path/to/partition}}`
+
+- Create a `/dev/btrfs-control` control device when `mknod` is not installed:
+
+`sudo btrfs rescue create-control-device`