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- 29 Oct, 2002 1 commit
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Andrew Morton authored
Two fixes here. First: Fixes a BUG() which occurs if you try to perform O_DIRECT IO against a blockdev which has an fs mounted on it. (We should be able to do that). What happens is that do_invalidatepage() ends up calling discard_buffer() on buffers which it couldn't strip. That clears buffer_mapped() against useful things like the superblock buffer_head. The next submit_bh() goes BUG over the write of an unmapped buffer. So just run try_to_release_page() (aka try_to_free_buffers()) on the invalidate path. Second: The invalidate_inode_pages() functions are best-effort pagecache shrinkers. They are used against pages inside i_size and are not supposed to throw away dirty data. However it is possible for another CPU to run set_page_dirty() against one of these pages after invalidate_inode_pages() has decided that it is clean. This could happen if someone was performing O_DIRECT IO against a file which was also mapped with MAP_SHARED. So recheck the dirty state of the page inside the mapping->page_lock and back out if the page has just been marked dirty. This will also prevent the remove_from_page_cache() BUG which will occur if someone marks the page dirty between the clear_page_dirty() and remove_from_page_cache() calls in truncate_complete_page().
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- 05 Oct, 2002 1 commit
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Andrew Morton authored
The new truncate code needs to check page->mapping after acquiring the page lock. Because the page could have been unmapped by page reclaim or by invalidate_inode_pages() while we waited for the page lock. Also, the page may have been moved between a tmpfs inode and swapper_space. Because we don't hold the mapping->page_lock across the entire truncate operation any more. Also, change the initial truncate scan (the non-blocking one which is there to stop as much writeout as possible) so that it is immune to other CPUs decreasing page->index. Also fix negated test in invalidate_inode_pages2(). Not sure how that got in there.
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- 03 Oct, 2002 1 commit
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Andrew Morton authored
Rewrite these functions to use gang lookup. - This probably has similar performance to the old code in the common case. - It will be vastly quicker than current code for the worst case (single-page truncate). - invalidate_inode_pages() has been changed. It used to use page_count(page) as the "is it mapped into pagetables" heuristic. It now uses the (page->pte.direct != 0) heuristic. - Removes the worst cause of scheduling latency in the kernel. - It's a big code cleanup. - invalidate_inode_pages() has been changed to take an address_space *, not an inode *. - the maximum hold times for mapping->page_lock are enormously reduced, making it quite feasible to turn this into an irq-safe lock. Which, it seems, is a requirement for sane AIO<->direct-io integration, as well as possibly other AIO things. (Thanks Hugh for fixing a bug in this one as well). (Christoph added some stuff too)
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