X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=mm%2Ftruncate.c;h=1229211104f84beb0e05e5df891f1780d392e418;hb=549927620b04a8f8073ce2ee2a8977f209af2ee5;hp=11ca480701dd1ae38a85fc04aae7f3ebaedd6939;hpb=887ed2f3aecde2ff24e06666932dc5f144745044;p=safe%2Fjmp%2Flinux-2.6 diff --git a/mm/truncate.c b/mm/truncate.c index 11ca480..1229211 100644 --- a/mm/truncate.c +++ b/mm/truncate.c @@ -3,22 +3,26 @@ * * Copyright (C) 2002, Linus Torvalds * - * 10Sep2002 akpm@zip.com.au + * 10Sep2002 Andrew Morton * Initial version. */ #include +#include #include #include #include #include +#include #include +#include #include /* grr. try_to_release_page, do_invalidatepage */ +#include "internal.h" /** - * do_invalidatepage - invalidate part of all of a page + * do_invalidatepage - invalidate part or all of a page * @page: the page which is affected * @offset: the index of the truncation point * @@ -45,19 +49,48 @@ void do_invalidatepage(struct page *page, unsigned long offset) static inline void truncate_partial_page(struct page *page, unsigned partial) { - memclear_highpage_flush(page, partial, PAGE_CACHE_SIZE-partial); + zero_user_segment(page, partial, PAGE_CACHE_SIZE); if (PagePrivate(page)) do_invalidatepage(page, partial); } /* + * This cancels just the dirty bit on the kernel page itself, it + * does NOT actually remove dirty bits on any mmap's that may be + * around. It also leaves the page tagged dirty, so any sync + * activity will still find it on the dirty lists, and in particular, + * clear_page_dirty_for_io() will still look at the dirty bits in + * the VM. + * + * Doing this should *normally* only ever be done when a page + * is truncated, and is not actually mapped anywhere at all. However, + * fs/buffer.c does this when it notices that somebody has cleaned + * out all the buffers on a page without actually doing it through + * the VM. Can you say "ext3 is horribly ugly"? Tought you could. + */ +void cancel_dirty_page(struct page *page, unsigned int account_size) +{ + if (TestClearPageDirty(page)) { + struct address_space *mapping = page->mapping; + if (mapping && mapping_cap_account_dirty(mapping)) { + dec_zone_page_state(page, NR_FILE_DIRTY); + dec_bdi_stat(mapping->backing_dev_info, + BDI_RECLAIMABLE); + if (account_size) + task_io_account_cancelled_write(account_size); + } + } +} +EXPORT_SYMBOL(cancel_dirty_page); + +/* * 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(). + * becomes orphaned. It will be left on the LRU and may even be mapped into + * user pagetables if we're racing with filemap_fault(). * * 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 + * its lock, b) when a concurrent invalidate_mapping_pages got there first and * c) when tmpfs swizzles a page between a tmpfs inode and swapper_space. */ static void @@ -69,15 +102,16 @@ truncate_complete_page(struct address_space *mapping, struct page *page) if (PagePrivate(page)) do_invalidatepage(page, 0); - clear_page_dirty(page); - ClearPageUptodate(page); - ClearPageMappedToDisk(page); + cancel_dirty_page(page, PAGE_CACHE_SIZE); + + clear_page_mlock(page); remove_from_page_cache(page); + ClearPageMappedToDisk(page); page_cache_release(page); /* pagecache ref */ } /* - * This is for invalidate_inode_pages(). That function can be called at + * This is for invalidate_mapping_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 use remove_mapping which safely * discards clean, unused pages. @@ -95,15 +129,14 @@ invalidate_complete_page(struct address_space *mapping, struct page *page) if (PagePrivate(page) && !try_to_release_page(page, 0)) return 0; + clear_page_mlock(page); ret = remove_mapping(mapping, page); - ClearPageUptodate(page); return ret; } /** - * truncate_inode_pages - truncate range of pages specified by start and - * end byte offsets + * truncate_inode_pages - truncate range of pages specified by start & end byte offsets * @mapping: mapping to truncate * @lstart: offset from which to truncate * @lend: offset to which to truncate @@ -157,12 +190,17 @@ void truncate_inode_pages_range(struct address_space *mapping, if (page_index > next) next = page_index; next++; - if (TestSetPageLocked(page)) + if (!trylock_page(page)) continue; if (PageWriteback(page)) { unlock_page(page); continue; } + if (page_mapped(page)) { + unmap_mapping_range(mapping, + (loff_t)page_index<index<index > next) next = page->index; next++; @@ -224,21 +267,8 @@ void truncate_inode_pages(struct address_space *mapping, loff_t lstart) } 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) +unsigned long __invalidate_mapping_pages(struct address_space *mapping, + pgoff_t start, pgoff_t end, bool be_atomic) { struct pagevec pvec; pgoff_t next = start; @@ -253,7 +283,7 @@ unsigned long invalidate_mapping_pages(struct address_space *mapping, pgoff_t index; int lock_failed; - lock_failed = TestSetPageLocked(page); + lock_failed = !trylock_page(page); /* * We really shouldn't be looking at the ->index of an @@ -279,22 +309,38 @@ unlock: break; } pagevec_release(&pvec); + if (likely(!be_atomic)) + cond_resched(); } return ret; } -unsigned long invalidate_inode_pages(struct address_space *mapping) +/** + * 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) { - return invalidate_mapping_pages(mapping, 0, ~0UL); + return __invalidate_mapping_pages(mapping, start, end, false); } -EXPORT_SYMBOL(invalidate_inode_pages); +EXPORT_SYMBOL(invalidate_mapping_pages); /* * This is like invalidate_complete_page(), except it ignores the page's * refcount. We do this because invalidate_inode_pages2() needs stronger * invalidation guarantees, and cannot afford to leave pages behind because - * shrink_list() has a temp ref on them, or because they're transiently sitting - * in the lru_cache_add() pagevecs. + * shrink_page_list() has a temp ref on them, or because they're transiently + * sitting in the lru_cache_add() pagevecs. */ static int invalidate_complete_page2(struct address_space *mapping, struct page *page) @@ -305,21 +351,30 @@ invalidate_complete_page2(struct address_space *mapping, struct page *page) if (PagePrivate(page) && !try_to_release_page(page, GFP_KERNEL)) return 0; - write_lock_irq(&mapping->tree_lock); + spin_lock_irq(&mapping->tree_lock); if (PageDirty(page)) goto failed; + clear_page_mlock(page); BUG_ON(PagePrivate(page)); __remove_from_page_cache(page); - write_unlock_irq(&mapping->tree_lock); - ClearPageUptodate(page); + spin_unlock_irq(&mapping->tree_lock); page_cache_release(page); /* pagecache ref */ return 1; failed: - write_unlock_irq(&mapping->tree_lock); + spin_unlock_irq(&mapping->tree_lock); 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 @@ -329,7 +384,7 @@ failed: * Any pages which are found to be mapped into pagetables are unmapped prior to * invalidation. * - * Returns -EIO if any pages could not be invalidated. + * Returns -EBUSY if any pages could not be invalidated. */ int invalidate_inode_pages2_range(struct address_space *mapping, pgoff_t start, pgoff_t end) @@ -338,18 +393,18 @@ int invalidate_inode_pages2_range(struct address_space *mapping, pgoff_t next; int i; int ret = 0; + int ret2 = 0; int did_range_unmap = 0; int wrapped = 0; pagevec_init(&pvec, 0); next = start; - while (next <= end && !ret && !wrapped && + while (next <= end && !wrapped && pagevec_lookup(&pvec, mapping, next, min(end - next, (pgoff_t)PAGEVEC_SIZE - 1) + 1)) { - for (i = 0; !ret && i < pagevec_count(&pvec); i++) { + for (i = 0; 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) { @@ -365,7 +420,7 @@ int invalidate_inode_pages2_range(struct address_space *mapping, break; } wait_on_page_writeback(page); - while (page_mapped(page)) { + if (page_mapped(page)) { if (!did_range_unmap) { /* * Zap the rest of the file in one hit. @@ -385,18 +440,19 @@ int invalidate_inode_pages2_range(struct address_space *mapping, PAGE_CACHE_SIZE, 0); } } - was_dirty = test_clear_page_dirty(page); - if (!invalidate_complete_page2(mapping, page)) { - if (was_dirty) - set_page_dirty(page); - ret = -EIO; + BUG_ON(page_mapped(page)); + ret2 = do_launder_page(mapping, page); + if (ret2 == 0) { + if (!invalidate_complete_page2(mapping, page)) + ret2 = -EBUSY; } + if (ret2 < 0) + ret = ret2; unlock_page(page); } pagevec_release(&pvec); cond_resched(); } - WARN_ON_ONCE(ret); return ret; } EXPORT_SYMBOL_GPL(invalidate_inode_pages2_range);