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| author | Konstantin Khlebnikov <khlebnikov@yandex-team.ru> | 2015-04-15 00:45:27 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2015-04-15 01:49:01 +0200 |
| commit | b9ea25152e56365ce149b9a39637cd7a16eec556 (patch) | |
| tree | e8ab83d71a0bea5330d38e77e948170c0054d2a3 /fs/buffer.c | |
| parent | mm: incorporate zero pages into transparent huge pages (diff) | |
| download | linux-b9ea25152e56365ce149b9a39637cd7a16eec556.tar.xz linux-b9ea25152e56365ce149b9a39637cd7a16eec556.zip | |
page_writeback: clean up mess around cancel_dirty_page()
This patch replaces cancel_dirty_page() with a helper function
account_page_cleaned() which only updates counters. It's called from
truncate_complete_page() and from try_to_free_buffers() (hack for ext3).
Page is locked in both cases, page-lock protects against concurrent
dirtiers: see commit 2d6d7f982846 ("mm: protect set_page_dirty() from
ongoing truncation").
Delete_from_page_cache() shouldn't be called for dirty pages, they must
be handled by caller (either written or truncated). This patch treats
final dirty accounting fixup at the end of __delete_from_page_cache() as
a debug check and adds WARN_ON_ONCE() around it. If something removes
dirty pages without proper handling that might be a bug and unwritten
data might be lost.
Hugetlbfs has no dirty pages accounting, ClearPageDirty() is enough
here.
cancel_dirty_page() in nfs_wb_page_cancel() is redundant. This is
helper for nfs_invalidate_page() and it's called only in case complete
invalidation.
The mess was started in v2.6.20 after commits 46d2277c796f ("Clean up
and make try_to_free_buffers() not race with dirty pages") and
3e67c0987d75 ("truncate: clear page dirtiness before running
try_to_free_buffers()") first was reverted right in v2.6.20 in commit
ecdfc9787fe5 ("Resurrect 'try_to_free_buffers()' VM hackery"), second in
v2.6.25 commit a2b345642f53 ("Fix dirty page accounting leak with ext3
data=journal").
Custom fixes were introduced between these points. NFS in v2.6.23, commit
1b3b4a1a2deb ("NFS: Fix a write request leak in nfs_invalidate_page()").
Kludge in __delete_from_page_cache() in v2.6.24, commit 3a6927906f1b ("Do
dirty page accounting when removing a page from the page cache"). Since
v2.6.25 all of them are redundant.
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: Tejun Heo <tj@kernel.org>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/buffer.c')
| -rw-r--r-- | fs/buffer.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/fs/buffer.c b/fs/buffer.c index 20805db2c987..c7a5602d01ee 100644 --- a/fs/buffer.c +++ b/fs/buffer.c @@ -3243,8 +3243,8 @@ int try_to_free_buffers(struct page *page) * to synchronise against __set_page_dirty_buffers and prevent the * dirty bit from being lost. */ - if (ret) - cancel_dirty_page(page, PAGE_CACHE_SIZE); + if (ret && TestClearPageDirty(page)) + account_page_cleaned(page, mapping); spin_unlock(&mapping->private_lock); out: if (buffers_to_free) { |