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authorMike Christie <mchristi@redhat.com>2016-06-05 15:32:25 -0400
committerJens Axboe <axboe@fb.com>2016-06-07 15:41:38 -0400
commit28a8f0d317bf225ff15008f5dd66ae16242dd843 (patch)
tree4ed24aee241907a3612a61f8cc634acd10989c21 /Documentation/device-mapper
parenta418090aa88b9b531ac1f504d6bb8c0e9b04ccb7 (diff)
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
14 14
15We log things in order of completion once we are sure the write is no longer in 15We log things in order of completion once we are sure the write is no longer in
16cache. This means that normal WRITE requests are not actually logged until the 16cache. This means that normal WRITE requests are not actually logged until the
17next REQ_FLUSH request. This is to make it easier for userspace to replay the 17next REQ_PREFLUSH request. This is to make it easier for userspace to replay
18log in a way that correlates to what is on disk and not what is in cache, to 18the log in a way that correlates to what is on disk and not what is in cache,
19make it easier to detect improper waiting/flushing. 19to make it easier to detect improper waiting/flushing.
20 20
21This works by attaching all WRITE requests to a list once the write completes. 21This works by attaching all WRITE requests to a list once the write completes.
22Once we see a REQ_FLUSH request we splice this list onto the request and once 22Once we see a REQ_PREFLUSH request we splice this list onto the request and once
23the FLUSH request completes we log all of the WRITEs and then the FLUSH. Only 23the FLUSH request completes we log all of the WRITEs and then the FLUSH. Only
24completed WRITEs, at the time the REQ_FLUSH is issued, are added in order to 24completed WRITEs, at the time the REQ_PREFLUSH is issued, are added in order to
25simulate the worst case scenario with regard to power failures. Consider the 25simulate the worst case scenario with regard to power failures. Consider the
26following example (W means write, C means complete): 26following example (W means write, C means complete):
27 27