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authorMike Christie <mchristi@redhat.com>2016-06-05 22:32:25 +0300
committerJens Axboe <axboe@fb.com>2016-06-07 22:41:38 +0300
commit28a8f0d317bf225ff15008f5dd66ae16242dd843 (patch)
tree4ed24aee241907a3612a61f8cc634acd10989c21 /Documentation/device-mapper
parenta418090aa88b9b531ac1f504d6bb8c0e9b04ccb7 (diff)
downloadlinux-28a8f0d317bf225ff15008f5dd66ae16242dd843.tar.xz
block, drivers, fs: rename REQ_FLUSH to REQ_PREFLUSH
To avoid confusion between REQ_OP_FLUSH, which is handled by request_fn drivers, and upper layers requesting the block layer perform a flush sequence along with possibly a WRITE, this patch renames REQ_FLUSH to REQ_PREFLUSH. Signed-off-by: Mike Christie <mchristi@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'Documentation/device-mapper')
-rw-r--r--Documentation/device-mapper/log-writes.txt10
1 files changed, 5 insertions, 5 deletions
diff --git a/Documentation/device-mapper/log-writes.txt b/Documentation/device-mapper/log-writes.txt
index c10f30c9b534..f4ebcbaf50f3 100644
--- a/Documentation/device-mapper/log-writes.txt
+++ b/Documentation/device-mapper/log-writes.txt
@@ -14,14 +14,14 @@ Log Ordering
We log things in order of completion once we are sure the write is no longer in
cache. This means that normal WRITE requests are not actually logged until the
-next REQ_FLUSH request. This is to make it easier for userspace to replay the
-log in a way that correlates to what is on disk and not what is in cache, to
-make it easier to detect improper waiting/flushing.
+next REQ_PREFLUSH request. This is to make it easier for userspace to replay
+the log in a way that correlates to what is on disk and not what is in cache,
+to make it easier to detect improper waiting/flushing.
This works by attaching all WRITE requests to a list once the write completes.
-Once we see a REQ_FLUSH request we splice this list onto the request and once
+Once we see a REQ_PREFLUSH request we splice this list onto the request and once
the FLUSH request completes we log all of the WRITEs and then the FLUSH. Only
-completed WRITEs, at the time the REQ_FLUSH is issued, are added in order to
+completed WRITEs, at the time the REQ_PREFLUSH is issued, are added in order to
simulate the worst case scenario with regard to power failures. Consider the
following example (W means write, C means complete):