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linux/fs/btrfs/dev-replace.h

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Btrfs: add code to scrub to copy read data to another disk 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 adds code to scrub to allow the scrub code to copy read data to another disk. One goal is to be able to perform as fast as possible. Therefore the write requests are collected until huge bios are built, and the write process is decoupled from the read process with some kind of flow control, of course, in order to limit the allocated memory. The best performance on spinning disks could by reached when the head movements are avoided as much as possible. Therefore a single worker is used to interface the read process with the write process. The regular scrub operation works as fast as before, it is not negatively influenced and actually it is more or less unchanged. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-06 11:43:11 +01:00
Btrfs: add new sources for device replace code This adds a new file to the sources together with the header file and the changes to ioctl.h and ctree.h that are required by the new C source file. Additionally, 4 new functions are added to volume.c that deal with device creation and destruction. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-05 17:33:06 +01:00
Btrfs: add code to scrub to copy read data to another disk 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 adds code to scrub to allow the scrub code to copy read data to another disk. One goal is to be able to perform as fast as possible. Therefore the write requests are collected until huge bios are built, and the write process is decoupled from the read process with some kind of flow control, of course, in order to limit the allocated memory. The best performance on spinning disks could by reached when the head movements are avoided as much as possible. Therefore a single worker is used to interface the read process with the write process. The regular scrub operation works as fast as before, it is not negatively influenced and actually it is more or less unchanged. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-06 11:43:11 +01:00