|author||Nikita Danilov <firstname.lastname@example.org>||2005-05-01 08:58:37 -0700|
|committer||Linus Torvalds <email@example.com>||2005-05-01 08:58:37 -0700|
[PATCH] doc: Locking update
Make the Locking document truer. Signed-off-by: Andrew Morton <firstname.lastname@example.org> Signed-off-by: Linus Torvalds <email@example.com>
Diffstat (limited to 'Documentation')
1 files changed, 6 insertions, 2 deletions
diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking
index a934baeeb33a..1045da582b9b 100644
@@ -219,8 +219,12 @@ This may also be done to avoid internal deadlocks, but rarely.
If the filesytem is called for sync then it must wait on any
in-progress I/O and then start new I/O.
-The filesystem should unlock the page synchronously, before returning
-to the caller.
+The filesystem should unlock the page synchronously, before returning to the
+caller, unless ->writepage() returns special WRITEPAGE_ACTIVATE
+value. WRITEPAGE_ACTIVATE means that page cannot really be written out
+currently, and VM should stop calling ->writepage() on this page for some
+time. VM does this by moving page to the head of the active list, hence the
Unless the filesystem is going to redirty_page_for_writepage(), unlock the page
and return zero, writepage *must* run set_page_writeback() against the page,