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authorTrond Myklebust <Trond.Myklebust@netapp.com>2007-01-10 23:15:39 -0800
committerLinus Torvalds <torvalds@woody.osdl.org>2007-01-11 18:18:21 -0800
commite3db7691e9f3dff3289f64e3d98583e28afe03db (patch)
treee05542d8d8bb545545c5b535381a8c1fcb369a03 /mm/truncate.c
parent07031e14c1127fc7e1a5b98dfcc59f434e025104 (diff)
downloadvexpress-lsk-e3db7691e9f3dff3289f64e3d98583e28afe03db.tar.gz
[PATCH] NFS: Fix race in nfs_release_page()
NFS: Fix race in nfs_release_page() invalidate_inode_pages2() may find the dirty bit has been set on a page owing to the fact that the page may still be mapped after it was locked. Only after the call to unmap_mapping_range() are we sure that the page can no longer be dirtied. In order to fix this, NFS has hooked the releasepage() method and tries to write the page out between the call to unmap_mapping_range() and the call to remove_mapping(). This, however leads to deadlocks in the page reclaim code, where the page may be locked without holding a reference to the inode or dentry. Fix is to add a new address_space_operation, launder_page(), which will attempt to write out a dirty page without releasing the page lock. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com> Also, the bare SetPageDirty() can skew all sort of accounting leading to other nasties. [akpm@osdl.org: cleanup] Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Trond Myklebust <Trond.Myklebust@netapp.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'mm/truncate.c')
-rw-r--r--mm/truncate.c12
1 files changed, 11 insertions, 1 deletions
diff --git a/mm/truncate.c b/mm/truncate.c
index ecdfdcc5052..6c79ca4a1ca 100644
--- a/mm/truncate.c
+++ b/mm/truncate.c
@@ -341,6 +341,15 @@ failed:
return 0;
}
+static int do_launder_page(struct address_space *mapping, struct page *page)
+{
+ if (!PageDirty(page))
+ return 0;
+ if (page->mapping != mapping || mapping->a_ops->launder_page == NULL)
+ return 0;
+ return mapping->a_ops->launder_page(page);
+}
+
/**
* invalidate_inode_pages2_range - remove range of pages from an address_space
* @mapping: the address_space
@@ -405,7 +414,8 @@ int invalidate_inode_pages2_range(struct address_space *mapping,
PAGE_CACHE_SIZE, 0);
}
}
- if (!invalidate_complete_page2(mapping, page))
+ ret = do_launder_page(mapping, page);
+ if (ret == 0 && !invalidate_complete_page2(mapping, page))
ret = -EIO;
unlock_page(page);
}