X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=mm%2Ftruncate.c;h=e87e37244829ce03abc22673cda7eeb37f6fff0a;hb=de3fab39348dff18c69a0cd04efee9c276a02f51;hp=ff78505453d42ac45c5e3fd563ff05606a9d3786;hpb=c9e51e4180696aa67915ec5665e4ec74125565de;p=safe%2Fjmp%2Flinux-2.6 diff --git a/mm/truncate.c b/mm/truncate.c index ff78505..e87e372 100644 --- a/mm/truncate.c +++ b/mm/truncate.c @@ -3,11 +3,12 @@ * * Copyright (C) 2002, Linus Torvalds * - * 10Sep2002 akpm@zip.com.au + * 10Sep2002 Andrew Morton * Initial version. */ #include +#include #include #include #include @@ -17,10 +18,11 @@ #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 * @@ -47,8 +49,8 @@ void do_invalidatepage(struct page *page, unsigned long offset) static inline void truncate_partial_page(struct page *page, unsigned partial) { - zero_user_page(page, partial, PAGE_CACHE_SIZE - partial, KM_USER0); - if (PagePrivate(page)) + zero_user_segment(page, partial, PAGE_CACHE_SIZE); + if (page_has_private(page)) do_invalidatepage(page, partial); } @@ -83,7 +85,7 @@ 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 + * 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 @@ -91,21 +93,22 @@ EXPORT_SYMBOL(cancel_dirty_page); * 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 +static int truncate_complete_page(struct address_space *mapping, struct page *page) { if (page->mapping != mapping) - return; + return -EIO; - cancel_dirty_page(page, PAGE_CACHE_SIZE); - - if (PagePrivate(page)) + if (page_has_private(page)) do_invalidatepage(page, 0); + cancel_dirty_page(page, PAGE_CACHE_SIZE); + + clear_page_mlock(page); remove_from_page_cache(page); - ClearPageUptodate(page); ClearPageMappedToDisk(page); page_cache_release(page); /* pagecache ref */ + return 0; } /* @@ -124,17 +127,62 @@ 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)) + if (page_has_private(page) && !try_to_release_page(page, 0)) return 0; + clear_page_mlock(page); ret = remove_mapping(mapping, page); return ret; } +int truncate_inode_page(struct address_space *mapping, struct page *page) +{ + if (page_mapped(page)) { + unmap_mapping_range(mapping, + (loff_t)page->index << PAGE_CACHE_SHIFT, + PAGE_CACHE_SIZE, 0); + } + return truncate_complete_page(mapping, page); +} + +/* + * Used to get rid of pages on hardware memory corruption. + */ +int generic_error_remove_page(struct address_space *mapping, struct page *page) +{ + if (!mapping) + return -EINVAL; + /* + * Only punch for normal data pages for now. + * Handling other types like directories would need more auditing. + */ + if (!S_ISREG(mapping->host->i_mode)) + return -EIO; + return truncate_inode_page(mapping, page); +} +EXPORT_SYMBOL(generic_error_remove_page); + +/* + * Safely invalidate one page from its pagecache mapping. + * It only drops clean, unused pages. The page must be locked. + * + * Returns 1 if the page is successfully invalidated, otherwise 0. + */ +int invalidate_inode_page(struct page *page) +{ + struct address_space *mapping = page_mapping(page); + if (!mapping) + return 0; + if (PageDirty(page) || PageWriteback(page)) + return 0; + if (page_mapped(page)) + return 0; + return invalidate_complete_page(mapping, page); +} + /** - * 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 @@ -188,18 +236,13 @@ 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++; - truncate_complete_page(mapping, page); unlock_page(page); } pagevec_release(&pvec); + mem_cgroup_uncharge_end(); } } EXPORT_SYMBOL(truncate_inode_pages_range); @@ -265,8 +305,21 @@ void truncate_inode_pages(struct address_space *mapping, loff_t lstart) } EXPORT_SYMBOL(truncate_inode_pages); -unsigned long __invalidate_mapping_pages(struct address_space *mapping, - pgoff_t start, pgoff_t end, bool be_atomic) +/** + * 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; @@ -276,12 +329,13 @@ unsigned long __invalidate_mapping_pages(struct address_space *mapping, pagevec_init(&pvec, 0); while (next <= end && pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) { + mem_cgroup_uncharge_start(); for (i = 0; i < pagevec_count(&pvec); i++) { struct page *page = pvec.pages[i]; 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 @@ -296,41 +350,18 @@ unsigned long __invalidate_mapping_pages(struct address_space *mapping, if (lock_failed) continue; - if (PageDirty(page) || PageWriteback(page)) - goto unlock; - if (page_mapped(page)) - goto unlock; - ret += invalidate_complete_page(mapping, page); -unlock: + ret += invalidate_inode_page(page); + unlock_page(page); if (next > end) break; } pagevec_release(&pvec); - if (likely(!be_atomic)) - cond_resched(); + mem_cgroup_uncharge_end(); + cond_resched(); } return ret; } - -/** - * 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, start, end, false); -} EXPORT_SYMBOL(invalidate_mapping_pages); /* @@ -346,21 +377,22 @@ invalidate_complete_page2(struct address_space *mapping, struct page *page) if (page->mapping != mapping) return 0; - if (PagePrivate(page) && !try_to_release_page(page, GFP_KERNEL)) + if (page_has_private(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; - BUG_ON(PagePrivate(page)); + clear_page_mlock(page); + BUG_ON(page_has_private(page)); __remove_from_page_cache(page); - write_unlock_irq(&mapping->tree_lock); - ClearPageUptodate(page); + spin_unlock_irq(&mapping->tree_lock); + mem_cgroup_uncharge_cache_page(page); page_cache_release(page); /* pagecache ref */ return 1; failed: - write_unlock_irq(&mapping->tree_lock); + spin_unlock_irq(&mapping->tree_lock); return 0; } @@ -382,7 +414,7 @@ static int do_launder_page(struct address_space *mapping, struct page *page) * 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) @@ -391,6 +423,7 @@ 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; @@ -399,6 +432,7 @@ int invalidate_inode_pages2_range(struct address_space *mapping, while (next <= end && !wrapped && pagevec_lookup(&pvec, mapping, next, min(end - next, (pgoff_t)PAGEVEC_SIZE - 1) + 1)) { + mem_cgroup_uncharge_start(); for (i = 0; i < pagevec_count(&pvec); i++) { struct page *page = pvec.pages[i]; pgoff_t page_index; @@ -438,12 +472,17 @@ int invalidate_inode_pages2_range(struct address_space *mapping, } } BUG_ON(page_mapped(page)); - ret = do_launder_page(mapping, page); - if (ret == 0 && !invalidate_complete_page2(mapping, page)) - ret = -EIO; + 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); + mem_cgroup_uncharge_end(); cond_resched(); } return ret; @@ -457,10 +496,72 @@ EXPORT_SYMBOL_GPL(invalidate_inode_pages2_range); * 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(struct address_space *mapping) { return invalidate_inode_pages2_range(mapping, 0, -1); } EXPORT_SYMBOL_GPL(invalidate_inode_pages2); + +/** + * truncate_pagecache - unmap and remove pagecache that has been truncated + * @inode: inode + * @old: old file offset + * @new: new file offset + * + * inode's new i_size must already be written before truncate_pagecache + * is called. + * + * This function should typically be called before the filesystem + * releases resources associated with the freed range (eg. deallocates + * blocks). This way, pagecache will always stay logically coherent + * with on-disk format, and the filesystem would not have to deal with + * situations such as writepage being called for a page that has already + * had its underlying blocks deallocated. + */ +void truncate_pagecache(struct inode *inode, loff_t old, loff_t new) +{ + struct address_space *mapping = inode->i_mapping; + + /* + * unmap_mapping_range is called twice, first simply for + * efficiency so that truncate_inode_pages does fewer + * single-page unmaps. However after this first call, and + * before truncate_inode_pages finishes, it is possible for + * private pages to be COWed, which remain after + * truncate_inode_pages finishes, hence the second + * unmap_mapping_range call must be made for correctness. + */ + unmap_mapping_range(mapping, new + PAGE_SIZE - 1, 0, 1); + truncate_inode_pages(mapping, new); + unmap_mapping_range(mapping, new + PAGE_SIZE - 1, 0, 1); +} +EXPORT_SYMBOL(truncate_pagecache); + +/** + * vmtruncate - unmap mappings "freed" by truncate() syscall + * @inode: inode of the file used + * @offset: file offset to start truncating + * + * NOTE! We have to be ready to update the memory sharing + * between the file and the memory map for a potential last + * incomplete page. Ugly, but necessary. + */ +int vmtruncate(struct inode *inode, loff_t offset) +{ + loff_t oldsize; + int error; + + error = inode_newsize_ok(inode, offset); + if (error) + return error; + oldsize = inode->i_size; + i_size_write(inode, offset); + truncate_pagecache(inode, oldsize, offset); + if (inode->i_op->truncate) + inode->i_op->truncate(inode); + + return error; +} +EXPORT_SYMBOL(vmtruncate);