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| author |   Nikita Danilov <nikita@clusterfs.com> | 2005-05-01 08:58:37 -0700 |
|---|---|---|
| committer |   Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-05-01 08:58:37 -0700 |
| commit | 2054606ad6dd6fee559fe790f190b15ed9355237 (patch) | |
| tree | 6c097981520088c6e6d13c2950f2d9ec9ba7f480 /Documentation | |
| parent | [PATCH] mm: use __GFP_NOMEMALLOC (diff) | |
| download | linux-dev-2054606ad6dd6fee559fe790f190b15ed9355237.tar.xz linux-dev-2054606ad6dd6fee559fe790f190b15ed9355237.zip | |
[PATCH] doc: Locking update
Make the Locking document truer.
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/filesystems/Locking | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking index a934baeeb33a..1045da582b9b 100644 --- a/Documentation/filesystems/Locking +++ b/Documentation/filesystems/Locking @@ -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 +name. 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, |