Btrfs: rename the scrub context structure
The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: NStefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: NChris Mason <chris.mason@fusionio.com>
Showing
想要评论请 注册 或 登录