diff options
author | OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> | 2006-06-23 02:03:26 -0700 |
---|---|---|
committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-06-23 07:42:49 -0700 |
commit | 111ebb6e6f7bd7de6d722c5848e95621f43700d9 (patch) | |
tree | bb00b13001db9be201e9b6d31468a79f4d1240bf /mm/vmscan.c | |
parent | 4c91c3648c620003cb7b21b8858f36cd6132e168 (diff) | |
download | kernel_samsung_smdk4412-111ebb6e6f7bd7de6d722c5848e95621f43700d9.zip kernel_samsung_smdk4412-111ebb6e6f7bd7de6d722c5848e95621f43700d9.tar.gz kernel_samsung_smdk4412-111ebb6e6f7bd7de6d722c5848e95621f43700d9.tar.bz2 |
[PATCH] writeback: fix range handling
When a writeback_control's `start' and `end' fields are used to
indicate a one-byte-range starting at file offset zero, the required
values of .start=0,.end=0 mean that the ->writepages() implementation
has no way of telling that it is being asked to perform a range
request. Because we're currently overloading (start == 0 && end == 0)
to mean "this is not a write-a-range request".
To make all this sane, the patch changes range of writeback_control.
So caller does: If it is calling ->writepages() to write pages, it
sets range (range_start/end or range_cyclic) always.
And if range_cyclic is true, ->writepages() thinks the range is
cyclic, otherwise it just uses range_start and range_end.
This patch does,
- Add LLONG_MAX, LLONG_MIN, ULLONG_MAX to include/linux/kernel.h
-1 is usually ok for range_end (type is long long). But, if someone did,
range_end += val; range_end is "val - 1"
u64val = range_end >> bits; u64val is "~(0ULL)"
or something, they are wrong. So, this adds LLONG_MAX to avoid nasty
things, and uses LLONG_MAX for range_end.
- All callers of ->writepages() sets range_start/end or range_cyclic.
- Fix updates of ->writeback_index. It seems already bit strange.
If it starts at 0 and ended by check of nr_to_write, this last
index may reduce chance to scan end of file. So, this updates
->writeback_index only if range_cyclic is true or whole-file is
scanned.
Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Cc: Nathan Scott <nathans@sgi.com>
Cc: Anton Altaparmakov <aia21@cantab.net>
Cc: Steven French <sfrench@us.ibm.com>
Cc: "Vladimir V. Saveliev" <vs@namesys.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'mm/vmscan.c')
-rw-r--r-- | mm/vmscan.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/mm/vmscan.c b/mm/vmscan.c index 46be8a0..bc5d4f4 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -339,6 +339,8 @@ pageout_t pageout(struct page *page, struct address_space *mapping) struct writeback_control wbc = { .sync_mode = WB_SYNC_NONE, .nr_to_write = SWAP_CLUSTER_MAX, + .range_start = 0, + .range_end = LLONG_MAX, .nonblocking = 1, .for_reclaim = 1, }; |