diff options
author | Mike Christie <mchristi@redhat.com> | 2016-06-05 15:32:25 -0400 |
---|---|---|
committer | Jens Axboe <axboe@fb.com> | 2016-06-07 15:41:38 -0400 |
commit | 28a8f0d317bf225ff15008f5dd66ae16242dd843 (patch) | |
tree | 4ed24aee241907a3612a61f8cc634acd10989c21 /Documentation/device-mapper | |
parent | a418090aa88b9b531ac1f504d6bb8c0e9b04ccb7 (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.txt | 10 |
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 | ||
15 | We log things in order of completion once we are sure the write is no longer in | 15 | We log things in order of completion once we are sure the write is no longer in |
16 | cache. This means that normal WRITE requests are not actually logged until the | 16 | cache. This means that normal WRITE requests are not actually logged until the |
17 | next REQ_FLUSH request. This is to make it easier for userspace to replay the | 17 | next REQ_PREFLUSH request. This is to make it easier for userspace to replay |
18 | log in a way that correlates to what is on disk and not what is in cache, to | 18 | the log in a way that correlates to what is on disk and not what is in cache, |
19 | make it easier to detect improper waiting/flushing. | 19 | to make it easier to detect improper waiting/flushing. |
20 | 20 | ||
21 | This works by attaching all WRITE requests to a list once the write completes. | 21 | This works by attaching all WRITE requests to a list once the write completes. |
22 | Once we see a REQ_FLUSH request we splice this list onto the request and once | 22 | Once we see a REQ_PREFLUSH request we splice this list onto the request and once |
23 | the FLUSH request completes we log all of the WRITEs and then the FLUSH. Only | 23 | the FLUSH request completes we log all of the WRITEs and then the FLUSH. Only |
24 | completed WRITEs, at the time the REQ_FLUSH is issued, are added in order to | 24 | completed WRITEs, at the time the REQ_PREFLUSH is issued, are added in order to |
25 | simulate the worst case scenario with regard to power failures. Consider the | 25 | simulate the worst case scenario with regard to power failures. Consider the |
26 | following example (W means write, C means complete): | 26 | following example (W means write, C means complete): |
27 | 27 | ||