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authorDavid Woodhouse <David.Woodhouse@intel.com>2013-01-30 00:40:14 +0100
committerChris Mason <chris.mason@fusionio.com>2013-02-01 20:24:23 +0100
commit53b381b3abeb86f12787a6c40fee9b2f71edc23b (patch)
treec1018ba2157778f0200d2ede0c0df48fe5df8f14 /fs/btrfs/disk-io.h
parentBtrfs: add rw argument to merge_bio_hook() (diff)
downloadlinux-53b381b3abeb86f12787a6c40fee9b2f71edc23b.tar.xz
linux-53b381b3abeb86f12787a6c40fee9b2f71edc23b.zip
Btrfs: RAID5 and RAID6
This builds on David Woodhouse's original Btrfs raid5/6 implementation. The code has changed quite a bit, blame Chris Mason for any bugs. Read/modify/write is done after the higher levels of the filesystem have prepared a given bio. This means the higher layers are not responsible for building full stripes, and they don't need to query for the topology of the extents that may get allocated during delayed allocation runs. It also means different files can easily share the same stripe. But, it does expose us to incorrect parity if we crash or lose power while doing a read/modify/write cycle. This will be addressed in a later commit. Scrub is unable to repair crc errors on raid5/6 chunks. Discard does not work on raid5/6 (yet) The stripe size is fixed at 64KiB per disk. This will be tunable in a later commit. Signed-off-by: Chris Mason <chris.mason@fusionio.com>
Diffstat (limited to 'fs/btrfs/disk-io.h')
-rw-r--r--fs/btrfs/disk-io.h7
1 files changed, 7 insertions, 0 deletions
diff --git a/fs/btrfs/disk-io.h b/fs/btrfs/disk-io.h
index 305c33efb0e3..034d7dc552b2 100644
--- a/fs/btrfs/disk-io.h
+++ b/fs/btrfs/disk-io.h
@@ -25,6 +25,13 @@
#define BTRFS_SUPER_MIRROR_MAX 3
#define BTRFS_SUPER_MIRROR_SHIFT 12
+enum {
+ BTRFS_WQ_ENDIO_DATA = 0,
+ BTRFS_WQ_ENDIO_METADATA = 1,
+ BTRFS_WQ_ENDIO_FREE_SPACE = 2,
+ BTRFS_WQ_ENDIO_RAID56 = 3,
+};
+
static inline u64 btrfs_sb_offset(int mirror)
{
u64 start = 16 * 1024;