From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sat, 16 Apr 2005 15:20:36 -0700 Subject: Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip! --- mm/truncate.c | 336 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 336 insertions(+) create mode 100644 mm/truncate.c (limited to 'mm/truncate.c') diff --git a/mm/truncate.c b/mm/truncate.c new file mode 100644 index 00000000000..c9a63f0b69a --- /dev/null +++ b/mm/truncate.c @@ -0,0 +1,336 @@ +/* + * mm/truncate.c - code for taking down pages from address_spaces + * + * Copyright (C) 2002, Linus Torvalds + * + * 10Sep2002 akpm@zip.com.au + * Initial version. + */ + +#include +#include +#include +#include +#include +#include /* grr. try_to_release_page, + block_invalidatepage */ + + +static int do_invalidatepage(struct page *page, unsigned long offset) +{ + int (*invalidatepage)(struct page *, unsigned long); + invalidatepage = page->mapping->a_ops->invalidatepage; + if (invalidatepage == NULL) + invalidatepage = block_invalidatepage; + return (*invalidatepage)(page, offset); +} + +static inline void truncate_partial_page(struct page *page, unsigned partial) +{ + memclear_highpage_flush(page, partial, PAGE_CACHE_SIZE-partial); + if (PagePrivate(page)) + do_invalidatepage(page, partial); +} + +/* + * If truncate cannot remove the fs-private metadata from the page, the page + * becomes anonymous. It will be left on the LRU and may even be mapped into + * user pagetables if we're racing with filemap_nopage(). + * + * We need to bale out if page->mapping is no longer equal to the original + * mapping. This happens a) when the VM reclaimed the page while we waited on + * its lock, b) when a concurrent invalidate_inode_pages got there first and + * c) when tmpfs swizzles a page between a tmpfs inode and swapper_space. + */ +static void +truncate_complete_page(struct address_space *mapping, struct page *page) +{ + if (page->mapping != mapping) + return; + + if (PagePrivate(page)) + do_invalidatepage(page, 0); + + clear_page_dirty(page); + ClearPageUptodate(page); + ClearPageMappedToDisk(page); + remove_from_page_cache(page); + page_cache_release(page); /* pagecache ref */ +} + +/* + * This is for invalidate_inode_pages(). That function can be called at + * any time, and is not supposed to throw away dirty pages. But pages can + * be marked dirty at any time too. So we re-check the dirtiness inside + * ->tree_lock. That provides exclusion against the __set_page_dirty + * functions. + * + * Returns non-zero if the page was successfully invalidated. + */ +static int +invalidate_complete_page(struct address_space *mapping, struct page *page) +{ + if (page->mapping != mapping) + return 0; + + if (PagePrivate(page) && !try_to_release_page(page, 0)) + return 0; + + write_lock_irq(&mapping->tree_lock); + if (PageDirty(page)) { + write_unlock_irq(&mapping->tree_lock); + return 0; + } + + BUG_ON(PagePrivate(page)); + __remove_from_page_cache(page); + write_unlock_irq(&mapping->tree_lock); + ClearPageUptodate(page); + page_cache_release(page); /* pagecache ref */ + return 1; +} + +/** + * truncate_inode_pages - truncate *all* the pages from an offset + * @mapping: mapping to truncate + * @lstart: offset from which to truncate + * + * Truncate the page cache at a set offset, removing the pages that are beyond + * that offset (and zeroing out partial pages). + * + * Truncate takes two passes - the first pass is nonblocking. It will not + * block on page locks and it will not block on writeback. The second pass + * will wait. This is to prevent as much IO as possible in the affected region. + * The first pass will remove most pages, so the search cost of the second pass + * is low. + * + * When looking at page->index outside the page lock we need to be careful to + * copy it into a local to avoid races (it could change at any time). + * + * We pass down the cache-hot hint to the page freeing code. Even if the + * mapping is large, it is probably the case that the final pages are the most + * recently touched, and freeing happens in ascending file offset order. + * + * Called under (and serialised by) inode->i_sem. + */ +void truncate_inode_pages(struct address_space *mapping, loff_t lstart) +{ + const pgoff_t start = (lstart + PAGE_CACHE_SIZE-1) >> PAGE_CACHE_SHIFT; + const unsigned partial = lstart & (PAGE_CACHE_SIZE - 1); + struct pagevec pvec; + pgoff_t next; + int i; + + if (mapping->nrpages == 0) + return; + + pagevec_init(&pvec, 0); + next = start; + while (pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) { + for (i = 0; i < pagevec_count(&pvec); i++) { + struct page *page = pvec.pages[i]; + pgoff_t page_index = page->index; + + if (page_index > next) + next = page_index; + next++; + if (TestSetPageLocked(page)) + continue; + if (PageWriteback(page)) { + unlock_page(page); + continue; + } + truncate_complete_page(mapping, page); + unlock_page(page); + } + pagevec_release(&pvec); + cond_resched(); + } + + if (partial) { + struct page *page = find_lock_page(mapping, start - 1); + if (page) { + wait_on_page_writeback(page); + truncate_partial_page(page, partial); + unlock_page(page); + page_cache_release(page); + } + } + + next = start; + for ( ; ; ) { + cond_resched(); + if (!pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) { + if (next == start) + break; + next = start; + continue; + } + for (i = 0; i < pagevec_count(&pvec); i++) { + struct page *page = pvec.pages[i]; + + lock_page(page); + wait_on_page_writeback(page); + if (page->index > next) + next = page->index; + next++; + truncate_complete_page(mapping, page); + unlock_page(page); + } + pagevec_release(&pvec); + } +} + +EXPORT_SYMBOL(truncate_inode_pages); + +/** + * invalidate_mapping_pages - Invalidate all the unlocked pages of one inode + * @mapping: the address_space which holds the pages to invalidate + * @start: the offset 'from' which to invalidate + * @end: the offset 'to' which to invalidate (inclusive) + * + * This function only removes the unlocked pages, if you want to + * remove all the pages of one inode, you must call truncate_inode_pages. + * + * invalidate_mapping_pages() will not block on IO activity. It will not + * invalidate pages which are dirty, locked, under writeback or mapped into + * pagetables. + */ +unsigned long invalidate_mapping_pages(struct address_space *mapping, + pgoff_t start, pgoff_t end) +{ + struct pagevec pvec; + pgoff_t next = start; + unsigned long ret = 0; + int i; + + pagevec_init(&pvec, 0); + while (next <= end && + pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) { + for (i = 0; i < pagevec_count(&pvec); i++) { + struct page *page = pvec.pages[i]; + + if (TestSetPageLocked(page)) { + next++; + continue; + } + if (page->index > next) + next = page->index; + next++; + if (PageDirty(page) || PageWriteback(page)) + goto unlock; + if (page_mapped(page)) + goto unlock; + ret += invalidate_complete_page(mapping, page); +unlock: + unlock_page(page); + if (next > end) + break; + } + pagevec_release(&pvec); + cond_resched(); + } + return ret; +} + +unsigned long invalidate_inode_pages(struct address_space *mapping) +{ + return invalidate_mapping_pages(mapping, 0, ~0UL); +} + +EXPORT_SYMBOL(invalidate_inode_pages); + +/** + * invalidate_inode_pages2_range - remove range of pages from an address_space + * @mapping - the address_space + * @start: the page offset 'from' which to invalidate + * @end: the page offset 'to' which to invalidate (inclusive) + * + * Any pages which are found to be mapped into pagetables are unmapped prior to + * invalidation. + * + * Returns -EIO if any pages could not be invalidated. + */ +int invalidate_inode_pages2_range(struct address_space *mapping, + pgoff_t start, pgoff_t end) +{ + struct pagevec pvec; + pgoff_t next; + int i; + int ret = 0; + int did_range_unmap = 0; + int wrapped = 0; + + pagevec_init(&pvec, 0); + next = start; + while (next <= end && !ret && !wrapped && + pagevec_lookup(&pvec, mapping, next, + min(end - next, (pgoff_t)PAGEVEC_SIZE - 1) + 1)) { + for (i = 0; !ret && i < pagevec_count(&pvec); i++) { + struct page *page = pvec.pages[i]; + pgoff_t page_index; + int was_dirty; + + lock_page(page); + if (page->mapping != mapping) { + unlock_page(page); + continue; + } + page_index = page->index; + next = page_index + 1; + if (next == 0) + wrapped = 1; + if (page_index > end) { + unlock_page(page); + break; + } + wait_on_page_writeback(page); + while (page_mapped(page)) { + if (!did_range_unmap) { + /* + * Zap the rest of the file in one hit. + */ + unmap_mapping_range(mapping, + page_index << PAGE_CACHE_SHIFT, + (end - page_index + 1) + << PAGE_CACHE_SHIFT, + 0); + did_range_unmap = 1; + } else { + /* + * Just zap this page + */ + unmap_mapping_range(mapping, + page_index << PAGE_CACHE_SHIFT, + PAGE_CACHE_SIZE, 0); + } + } + was_dirty = test_clear_page_dirty(page); + if (!invalidate_complete_page(mapping, page)) { + if (was_dirty) + set_page_dirty(page); + ret = -EIO; + } + unlock_page(page); + } + pagevec_release(&pvec); + cond_resched(); + } + return ret; +} +EXPORT_SYMBOL_GPL(invalidate_inode_pages2_range); + +/** + * invalidate_inode_pages2 - remove all pages from an address_space + * @mapping - the address_space + * + * Any pages which are found to be mapped into pagetables are unmapped prior to + * invalidation. + * + * Returns -EIO if any pages could not be invalidated. + */ +int invalidate_inode_pages2(struct address_space *mapping) +{ + return invalidate_inode_pages2_range(mapping, 0, -1); +} +EXPORT_SYMBOL_GPL(invalidate_inode_pages2); -- cgit v1.2.3