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author | NeilBrown <neilb@cse.unsw.edu.au> | 2005-09-09 16:23:54 -0700 |
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committer | Linus Torvalds <torvalds@g5.osdl.org> | 2005-09-09 16:39:12 -0700 |
commit | 72626685dc66d455742a7f215a0535c551628b9e (patch) | |
tree | 91e19a61a5a3b782007132b6b2e353e8936dd656 /ipc/compat.c | |
parent | 0002b2718dd04da67c21f8a7830de8d95a9b0345 (diff) |
[PATCH] md: add write-intent-bitmap support to raid5
Most awkward part of this is delaying write requests until bitmap updates have
been flushed.
To achieve this, we have a sequence number (seq_flush) which is incremented
each time the raid5 is unplugged.
If the raid thread notices that this has changed, it flushes bitmap changes,
and assigned the value of seq_flush to seq_write.
When a write request arrives, it is given the number from seq_write, and that
write request may not complete until seq_flush is larger than the saved seq
number.
We have a new queue for storing stripes which are waiting for a bitmap flush
and an extra flag for stripes to record if the write was 'degraded' and so
should not clear the a bit in the bitmap.
Signed-off-by: Neil Brown <neilb@cse.unsw.edu.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'ipc/compat.c')
0 files changed, 0 insertions, 0 deletions