11da177e4SLinus Torvalds /* 21da177e4SLinus Torvalds * mm/truncate.c - code for taking down pages from address_spaces 31da177e4SLinus Torvalds * 41da177e4SLinus Torvalds * Copyright (C) 2002, Linus Torvalds 51da177e4SLinus Torvalds * 6e1f8e874SFrancois Cami * 10Sep2002 Andrew Morton 71da177e4SLinus Torvalds * Initial version. 81da177e4SLinus Torvalds */ 91da177e4SLinus Torvalds 101da177e4SLinus Torvalds #include <linux/kernel.h> 114af3c9ccSAlexey Dobriyan #include <linux/backing-dev.h> 125a0e3ad6STejun Heo #include <linux/gfp.h> 131da177e4SLinus Torvalds #include <linux/mm.h> 140fd0e6b0SNick Piggin #include <linux/swap.h> 15b95f1b31SPaul Gortmaker #include <linux/export.h> 161da177e4SLinus Torvalds #include <linux/pagemap.h> 1701f2705dSNate Diller #include <linux/highmem.h> 181da177e4SLinus Torvalds #include <linux/pagevec.h> 19e08748ceSAndrew Morton #include <linux/task_io_accounting_ops.h> 201da177e4SLinus Torvalds #include <linux/buffer_head.h> /* grr. try_to_release_page, 21aaa4059bSJan Kara do_invalidatepage */ 22c515e1fdSDan Magenheimer #include <linux/cleancache.h> 23ba470de4SRik van Riel #include "internal.h" 241da177e4SLinus Torvalds 250cd6144aSJohannes Weiner static void clear_exceptional_entry(struct address_space *mapping, 260cd6144aSJohannes Weiner pgoff_t index, void *entry) 270cd6144aSJohannes Weiner { 28449dd698SJohannes Weiner struct radix_tree_node *node; 29449dd698SJohannes Weiner void **slot; 30449dd698SJohannes Weiner 310cd6144aSJohannes Weiner /* Handled by shmem itself */ 320cd6144aSJohannes Weiner if (shmem_mapping(mapping)) 330cd6144aSJohannes Weiner return; 340cd6144aSJohannes Weiner 350cd6144aSJohannes Weiner spin_lock_irq(&mapping->tree_lock); 360cd6144aSJohannes Weiner /* 370cd6144aSJohannes Weiner * Regular page slots are stabilized by the page lock even 380cd6144aSJohannes Weiner * without the tree itself locked. These unlocked entries 390cd6144aSJohannes Weiner * need verification under the tree lock. 400cd6144aSJohannes Weiner */ 41449dd698SJohannes Weiner if (!__radix_tree_lookup(&mapping->page_tree, index, &node, &slot)) 42449dd698SJohannes Weiner goto unlock; 43449dd698SJohannes Weiner if (*slot != entry) 44449dd698SJohannes Weiner goto unlock; 45449dd698SJohannes Weiner radix_tree_replace_slot(slot, NULL); 4691b0abe3SJohannes Weiner mapping->nrshadows--; 47449dd698SJohannes Weiner if (!node) 48449dd698SJohannes Weiner goto unlock; 49449dd698SJohannes Weiner workingset_node_shadows_dec(node); 50449dd698SJohannes Weiner /* 51449dd698SJohannes Weiner * Don't track node without shadow entries. 52449dd698SJohannes Weiner * 53449dd698SJohannes Weiner * Avoid acquiring the list_lru lock if already untracked. 54449dd698SJohannes Weiner * The list_empty() test is safe as node->private_list is 55449dd698SJohannes Weiner * protected by mapping->tree_lock. 56449dd698SJohannes Weiner */ 57449dd698SJohannes Weiner if (!workingset_node_shadows(node) && 58449dd698SJohannes Weiner !list_empty(&node->private_list)) 59449dd698SJohannes Weiner list_lru_del(&workingset_shadow_nodes, &node->private_list); 60449dd698SJohannes Weiner __radix_tree_delete_node(&mapping->page_tree, node); 61449dd698SJohannes Weiner unlock: 620cd6144aSJohannes Weiner spin_unlock_irq(&mapping->tree_lock); 630cd6144aSJohannes Weiner } 641da177e4SLinus Torvalds 65cf9a2ae8SDavid Howells /** 6628bc44d7SFengguang Wu * do_invalidatepage - invalidate part or all of a page 67cf9a2ae8SDavid Howells * @page: the page which is affected 68d47992f8SLukas Czerner * @offset: start of the range to invalidate 69d47992f8SLukas Czerner * @length: length of the range to invalidate 70cf9a2ae8SDavid Howells * 71cf9a2ae8SDavid Howells * do_invalidatepage() is called when all or part of the page has become 72cf9a2ae8SDavid Howells * invalidated by a truncate operation. 73cf9a2ae8SDavid Howells * 74cf9a2ae8SDavid Howells * do_invalidatepage() does not have to release all buffers, but it must 75cf9a2ae8SDavid Howells * ensure that no dirty buffer is left outside @offset and that no I/O 76cf9a2ae8SDavid Howells * is underway against any of the blocks which are outside the truncation 77cf9a2ae8SDavid Howells * point. Because the caller is about to free (and possibly reuse) those 78cf9a2ae8SDavid Howells * blocks on-disk. 79cf9a2ae8SDavid Howells */ 80d47992f8SLukas Czerner void do_invalidatepage(struct page *page, unsigned int offset, 81d47992f8SLukas Czerner unsigned int length) 82cf9a2ae8SDavid Howells { 83d47992f8SLukas Czerner void (*invalidatepage)(struct page *, unsigned int, unsigned int); 84d47992f8SLukas Czerner 85cf9a2ae8SDavid Howells invalidatepage = page->mapping->a_ops->invalidatepage; 869361401eSDavid Howells #ifdef CONFIG_BLOCK 87cf9a2ae8SDavid Howells if (!invalidatepage) 88cf9a2ae8SDavid Howells invalidatepage = block_invalidatepage; 899361401eSDavid Howells #endif 90cf9a2ae8SDavid Howells if (invalidatepage) 91d47992f8SLukas Czerner (*invalidatepage)(page, offset, length); 92cf9a2ae8SDavid Howells } 93cf9a2ae8SDavid Howells 94ecdfc978SLinus Torvalds /* 95ecdfc978SLinus Torvalds * This cancels just the dirty bit on the kernel page itself, it 96ecdfc978SLinus Torvalds * does NOT actually remove dirty bits on any mmap's that may be 97ecdfc978SLinus Torvalds * around. It also leaves the page tagged dirty, so any sync 98ecdfc978SLinus Torvalds * activity will still find it on the dirty lists, and in particular, 99ecdfc978SLinus Torvalds * clear_page_dirty_for_io() will still look at the dirty bits in 100ecdfc978SLinus Torvalds * the VM. 101ecdfc978SLinus Torvalds * 102ecdfc978SLinus Torvalds * Doing this should *normally* only ever be done when a page 103ecdfc978SLinus Torvalds * is truncated, and is not actually mapped anywhere at all. However, 104ecdfc978SLinus Torvalds * fs/buffer.c does this when it notices that somebody has cleaned 105ecdfc978SLinus Torvalds * out all the buffers on a page without actually doing it through 106ecdfc978SLinus Torvalds * the VM. Can you say "ext3 is horribly ugly"? Tought you could. 107ecdfc978SLinus Torvalds */ 108fba2591bSLinus Torvalds void cancel_dirty_page(struct page *page, unsigned int account_size) 109fba2591bSLinus Torvalds { 1108368e328SLinus Torvalds if (TestClearPageDirty(page)) { 1118368e328SLinus Torvalds struct address_space *mapping = page->mapping; 1128368e328SLinus Torvalds if (mapping && mapping_cap_account_dirty(mapping)) { 1133e67c098SAndrew Morton dec_zone_page_state(page, NR_FILE_DIRTY); 114c9e51e41SPeter Zijlstra dec_bdi_stat(mapping->backing_dev_info, 115c9e51e41SPeter Zijlstra BDI_RECLAIMABLE); 1168368e328SLinus Torvalds if (account_size) 117fba2591bSLinus Torvalds task_io_account_cancelled_write(account_size); 118fba2591bSLinus Torvalds } 1193e67c098SAndrew Morton } 1208368e328SLinus Torvalds } 1218368e328SLinus Torvalds EXPORT_SYMBOL(cancel_dirty_page); 122fba2591bSLinus Torvalds 1231da177e4SLinus Torvalds /* 1241da177e4SLinus Torvalds * If truncate cannot remove the fs-private metadata from the page, the page 12562e1c553SShaohua Li * becomes orphaned. It will be left on the LRU and may even be mapped into 12654cb8821SNick Piggin * user pagetables if we're racing with filemap_fault(). 1271da177e4SLinus Torvalds * 1281da177e4SLinus Torvalds * We need to bale out if page->mapping is no longer equal to the original 1291da177e4SLinus Torvalds * mapping. This happens a) when the VM reclaimed the page while we waited on 130fc0ecff6SAndrew Morton * its lock, b) when a concurrent invalidate_mapping_pages got there first and 1311da177e4SLinus Torvalds * c) when tmpfs swizzles a page between a tmpfs inode and swapper_space. 1321da177e4SLinus Torvalds */ 133750b4987SNick Piggin static int 1341da177e4SLinus Torvalds truncate_complete_page(struct address_space *mapping, struct page *page) 1351da177e4SLinus Torvalds { 1361da177e4SLinus Torvalds if (page->mapping != mapping) 137750b4987SNick Piggin return -EIO; 1381da177e4SLinus Torvalds 139266cf658SDavid Howells if (page_has_private(page)) 140d47992f8SLukas Czerner do_invalidatepage(page, 0, PAGE_CACHE_SIZE); 1411da177e4SLinus Torvalds 142a2b34564SBjorn Steinbrink cancel_dirty_page(page, PAGE_CACHE_SIZE); 143a2b34564SBjorn Steinbrink 1441da177e4SLinus Torvalds ClearPageMappedToDisk(page); 1455adc7b51SMinchan Kim delete_from_page_cache(page); 146750b4987SNick Piggin return 0; 1471da177e4SLinus Torvalds } 1481da177e4SLinus Torvalds 1491da177e4SLinus Torvalds /* 150fc0ecff6SAndrew Morton * This is for invalidate_mapping_pages(). That function can be called at 1511da177e4SLinus Torvalds * any time, and is not supposed to throw away dirty pages. But pages can 1520fd0e6b0SNick Piggin * be marked dirty at any time too, so use remove_mapping which safely 1530fd0e6b0SNick Piggin * discards clean, unused pages. 1541da177e4SLinus Torvalds * 1551da177e4SLinus Torvalds * Returns non-zero if the page was successfully invalidated. 1561da177e4SLinus Torvalds */ 1571da177e4SLinus Torvalds static int 1581da177e4SLinus Torvalds invalidate_complete_page(struct address_space *mapping, struct page *page) 1591da177e4SLinus Torvalds { 1600fd0e6b0SNick Piggin int ret; 1610fd0e6b0SNick Piggin 1621da177e4SLinus Torvalds if (page->mapping != mapping) 1631da177e4SLinus Torvalds return 0; 1641da177e4SLinus Torvalds 165266cf658SDavid Howells if (page_has_private(page) && !try_to_release_page(page, 0)) 1661da177e4SLinus Torvalds return 0; 1671da177e4SLinus Torvalds 1680fd0e6b0SNick Piggin ret = remove_mapping(mapping, page); 1690fd0e6b0SNick Piggin 1700fd0e6b0SNick Piggin return ret; 1711da177e4SLinus Torvalds } 1721da177e4SLinus Torvalds 173750b4987SNick Piggin int truncate_inode_page(struct address_space *mapping, struct page *page) 174750b4987SNick Piggin { 175750b4987SNick Piggin if (page_mapped(page)) { 176750b4987SNick Piggin unmap_mapping_range(mapping, 177750b4987SNick Piggin (loff_t)page->index << PAGE_CACHE_SHIFT, 178750b4987SNick Piggin PAGE_CACHE_SIZE, 0); 179750b4987SNick Piggin } 180750b4987SNick Piggin return truncate_complete_page(mapping, page); 181750b4987SNick Piggin } 182750b4987SNick Piggin 18383f78668SWu Fengguang /* 18425718736SAndi Kleen * Used to get rid of pages on hardware memory corruption. 18525718736SAndi Kleen */ 18625718736SAndi Kleen int generic_error_remove_page(struct address_space *mapping, struct page *page) 18725718736SAndi Kleen { 18825718736SAndi Kleen if (!mapping) 18925718736SAndi Kleen return -EINVAL; 19025718736SAndi Kleen /* 19125718736SAndi Kleen * Only punch for normal data pages for now. 19225718736SAndi Kleen * Handling other types like directories would need more auditing. 19325718736SAndi Kleen */ 19425718736SAndi Kleen if (!S_ISREG(mapping->host->i_mode)) 19525718736SAndi Kleen return -EIO; 19625718736SAndi Kleen return truncate_inode_page(mapping, page); 19725718736SAndi Kleen } 19825718736SAndi Kleen EXPORT_SYMBOL(generic_error_remove_page); 19925718736SAndi Kleen 20025718736SAndi Kleen /* 20183f78668SWu Fengguang * Safely invalidate one page from its pagecache mapping. 20283f78668SWu Fengguang * It only drops clean, unused pages. The page must be locked. 20383f78668SWu Fengguang * 20483f78668SWu Fengguang * Returns 1 if the page is successfully invalidated, otherwise 0. 20583f78668SWu Fengguang */ 20683f78668SWu Fengguang int invalidate_inode_page(struct page *page) 20783f78668SWu Fengguang { 20883f78668SWu Fengguang struct address_space *mapping = page_mapping(page); 20983f78668SWu Fengguang if (!mapping) 21083f78668SWu Fengguang return 0; 21183f78668SWu Fengguang if (PageDirty(page) || PageWriteback(page)) 21283f78668SWu Fengguang return 0; 21383f78668SWu Fengguang if (page_mapped(page)) 21483f78668SWu Fengguang return 0; 21583f78668SWu Fengguang return invalidate_complete_page(mapping, page); 21683f78668SWu Fengguang } 21783f78668SWu Fengguang 2181da177e4SLinus Torvalds /** 21973c1e204SLiu Bo * truncate_inode_pages_range - truncate range of pages specified by start & end byte offsets 2201da177e4SLinus Torvalds * @mapping: mapping to truncate 2211da177e4SLinus Torvalds * @lstart: offset from which to truncate 2225a720394SLukas Czerner * @lend: offset to which to truncate (inclusive) 2231da177e4SLinus Torvalds * 224d7339071SHans Reiser * Truncate the page cache, removing the pages that are between 2255a720394SLukas Czerner * specified offsets (and zeroing out partial pages 2265a720394SLukas Czerner * if lstart or lend + 1 is not page aligned). 2271da177e4SLinus Torvalds * 2281da177e4SLinus Torvalds * Truncate takes two passes - the first pass is nonblocking. It will not 2291da177e4SLinus Torvalds * block on page locks and it will not block on writeback. The second pass 2301da177e4SLinus Torvalds * will wait. This is to prevent as much IO as possible in the affected region. 2311da177e4SLinus Torvalds * The first pass will remove most pages, so the search cost of the second pass 2321da177e4SLinus Torvalds * is low. 2331da177e4SLinus Torvalds * 2341da177e4SLinus Torvalds * We pass down the cache-hot hint to the page freeing code. Even if the 2351da177e4SLinus Torvalds * mapping is large, it is probably the case that the final pages are the most 2361da177e4SLinus Torvalds * recently touched, and freeing happens in ascending file offset order. 2375a720394SLukas Czerner * 2385a720394SLukas Czerner * Note that since ->invalidatepage() accepts range to invalidate 2395a720394SLukas Czerner * truncate_inode_pages_range is able to handle cases where lend + 1 is not 2405a720394SLukas Czerner * page aligned properly. 2411da177e4SLinus Torvalds */ 242d7339071SHans Reiser void truncate_inode_pages_range(struct address_space *mapping, 243d7339071SHans Reiser loff_t lstart, loff_t lend) 2441da177e4SLinus Torvalds { 2455a720394SLukas Czerner pgoff_t start; /* inclusive */ 2465a720394SLukas Czerner pgoff_t end; /* exclusive */ 2475a720394SLukas Czerner unsigned int partial_start; /* inclusive */ 2485a720394SLukas Czerner unsigned int partial_end; /* exclusive */ 2491da177e4SLinus Torvalds struct pagevec pvec; 2500cd6144aSJohannes Weiner pgoff_t indices[PAGEVEC_SIZE]; 251b85e0effSHugh Dickins pgoff_t index; 2521da177e4SLinus Torvalds int i; 2531da177e4SLinus Torvalds 2543167760fSDan Magenheimer cleancache_invalidate_inode(mapping); 25591b0abe3SJohannes Weiner if (mapping->nrpages == 0 && mapping->nrshadows == 0) 2561da177e4SLinus Torvalds return; 2571da177e4SLinus Torvalds 2585a720394SLukas Czerner /* Offsets within partial pages */ 2595a720394SLukas Czerner partial_start = lstart & (PAGE_CACHE_SIZE - 1); 2605a720394SLukas Czerner partial_end = (lend + 1) & (PAGE_CACHE_SIZE - 1); 2615a720394SLukas Czerner 2625a720394SLukas Czerner /* 2635a720394SLukas Czerner * 'start' and 'end' always covers the range of pages to be fully 2645a720394SLukas Czerner * truncated. Partial pages are covered with 'partial_start' at the 2655a720394SLukas Czerner * start of the range and 'partial_end' at the end of the range. 2665a720394SLukas Czerner * Note that 'end' is exclusive while 'lend' is inclusive. 2675a720394SLukas Czerner */ 2685a720394SLukas Czerner start = (lstart + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; 2695a720394SLukas Czerner if (lend == -1) 2705a720394SLukas Czerner /* 2715a720394SLukas Czerner * lend == -1 indicates end-of-file so we have to set 'end' 2725a720394SLukas Czerner * to the highest possible pgoff_t and since the type is 2735a720394SLukas Czerner * unsigned we're using -1. 2745a720394SLukas Czerner */ 2755a720394SLukas Czerner end = -1; 2765a720394SLukas Czerner else 2775a720394SLukas Czerner end = (lend + 1) >> PAGE_CACHE_SHIFT; 278d7339071SHans Reiser 2791da177e4SLinus Torvalds pagevec_init(&pvec, 0); 280b85e0effSHugh Dickins index = start; 2810cd6144aSJohannes Weiner while (index < end && pagevec_lookup_entries(&pvec, mapping, index, 2820cd6144aSJohannes Weiner min(end - index, (pgoff_t)PAGEVEC_SIZE), 2830cd6144aSJohannes Weiner indices)) { 284e5598f8bSHugh Dickins mem_cgroup_uncharge_start(); 2851da177e4SLinus Torvalds for (i = 0; i < pagevec_count(&pvec); i++) { 2861da177e4SLinus Torvalds struct page *page = pvec.pages[i]; 2871da177e4SLinus Torvalds 288b85e0effSHugh Dickins /* We rely upon deletion not changing page->index */ 2890cd6144aSJohannes Weiner index = indices[i]; 2905a720394SLukas Czerner if (index >= end) 291d7339071SHans Reiser break; 292d7339071SHans Reiser 2930cd6144aSJohannes Weiner if (radix_tree_exceptional_entry(page)) { 2940cd6144aSJohannes Weiner clear_exceptional_entry(mapping, index, page); 2950cd6144aSJohannes Weiner continue; 2960cd6144aSJohannes Weiner } 2970cd6144aSJohannes Weiner 298529ae9aaSNick Piggin if (!trylock_page(page)) 2991da177e4SLinus Torvalds continue; 300b85e0effSHugh Dickins WARN_ON(page->index != index); 3011da177e4SLinus Torvalds if (PageWriteback(page)) { 3021da177e4SLinus Torvalds unlock_page(page); 3031da177e4SLinus Torvalds continue; 3041da177e4SLinus Torvalds } 305750b4987SNick Piggin truncate_inode_page(mapping, page); 3061da177e4SLinus Torvalds unlock_page(page); 3071da177e4SLinus Torvalds } 3080cd6144aSJohannes Weiner pagevec_remove_exceptionals(&pvec); 3091da177e4SLinus Torvalds pagevec_release(&pvec); 310e5598f8bSHugh Dickins mem_cgroup_uncharge_end(); 3111da177e4SLinus Torvalds cond_resched(); 312b85e0effSHugh Dickins index++; 3131da177e4SLinus Torvalds } 3141da177e4SLinus Torvalds 3155a720394SLukas Czerner if (partial_start) { 3161da177e4SLinus Torvalds struct page *page = find_lock_page(mapping, start - 1); 3171da177e4SLinus Torvalds if (page) { 3185a720394SLukas Czerner unsigned int top = PAGE_CACHE_SIZE; 3195a720394SLukas Czerner if (start > end) { 3205a720394SLukas Czerner /* Truncation within a single page */ 3215a720394SLukas Czerner top = partial_end; 3225a720394SLukas Czerner partial_end = 0; 3235a720394SLukas Czerner } 3241da177e4SLinus Torvalds wait_on_page_writeback(page); 3255a720394SLukas Czerner zero_user_segment(page, partial_start, top); 3265a720394SLukas Czerner cleancache_invalidate_page(mapping, page); 3275a720394SLukas Czerner if (page_has_private(page)) 3285a720394SLukas Czerner do_invalidatepage(page, partial_start, 3295a720394SLukas Czerner top - partial_start); 3301da177e4SLinus Torvalds unlock_page(page); 3311da177e4SLinus Torvalds page_cache_release(page); 3321da177e4SLinus Torvalds } 3331da177e4SLinus Torvalds } 3345a720394SLukas Czerner if (partial_end) { 3355a720394SLukas Czerner struct page *page = find_lock_page(mapping, end); 3365a720394SLukas Czerner if (page) { 3375a720394SLukas Czerner wait_on_page_writeback(page); 3385a720394SLukas Czerner zero_user_segment(page, 0, partial_end); 3395a720394SLukas Czerner cleancache_invalidate_page(mapping, page); 3405a720394SLukas Czerner if (page_has_private(page)) 3415a720394SLukas Czerner do_invalidatepage(page, 0, 3425a720394SLukas Czerner partial_end); 3435a720394SLukas Czerner unlock_page(page); 3445a720394SLukas Czerner page_cache_release(page); 3455a720394SLukas Czerner } 3465a720394SLukas Czerner } 3475a720394SLukas Czerner /* 3485a720394SLukas Czerner * If the truncation happened within a single page no pages 3495a720394SLukas Czerner * will be released, just zeroed, so we can bail out now. 3505a720394SLukas Czerner */ 3515a720394SLukas Czerner if (start >= end) 3525a720394SLukas Czerner return; 3531da177e4SLinus Torvalds 354b85e0effSHugh Dickins index = start; 3551da177e4SLinus Torvalds for ( ; ; ) { 3561da177e4SLinus Torvalds cond_resched(); 3570cd6144aSJohannes Weiner if (!pagevec_lookup_entries(&pvec, mapping, index, 358*792ceaefSHugh Dickins min(end - index, (pgoff_t)PAGEVEC_SIZE), indices)) { 359*792ceaefSHugh Dickins /* If all gone from start onwards, we're done */ 360b85e0effSHugh Dickins if (index == start) 3611da177e4SLinus Torvalds break; 362*792ceaefSHugh Dickins /* Otherwise restart to make sure all gone */ 363b85e0effSHugh Dickins index = start; 3641da177e4SLinus Torvalds continue; 3651da177e4SLinus Torvalds } 3660cd6144aSJohannes Weiner if (index == start && indices[0] >= end) { 367*792ceaefSHugh Dickins /* All gone out of hole to be punched, we're done */ 3680cd6144aSJohannes Weiner pagevec_remove_exceptionals(&pvec); 369d7339071SHans Reiser pagevec_release(&pvec); 370d7339071SHans Reiser break; 371d7339071SHans Reiser } 372569b846dSKAMEZAWA Hiroyuki mem_cgroup_uncharge_start(); 3731da177e4SLinus Torvalds for (i = 0; i < pagevec_count(&pvec); i++) { 3741da177e4SLinus Torvalds struct page *page = pvec.pages[i]; 3751da177e4SLinus Torvalds 376b85e0effSHugh Dickins /* We rely upon deletion not changing page->index */ 3770cd6144aSJohannes Weiner index = indices[i]; 378*792ceaefSHugh Dickins if (index >= end) { 379*792ceaefSHugh Dickins /* Restart punch to make sure all gone */ 380*792ceaefSHugh Dickins index = start - 1; 381d7339071SHans Reiser break; 382*792ceaefSHugh Dickins } 383b85e0effSHugh Dickins 3840cd6144aSJohannes Weiner if (radix_tree_exceptional_entry(page)) { 3850cd6144aSJohannes Weiner clear_exceptional_entry(mapping, index, page); 3860cd6144aSJohannes Weiner continue; 3870cd6144aSJohannes Weiner } 3880cd6144aSJohannes Weiner 3891da177e4SLinus Torvalds lock_page(page); 390b85e0effSHugh Dickins WARN_ON(page->index != index); 3911da177e4SLinus Torvalds wait_on_page_writeback(page); 392750b4987SNick Piggin truncate_inode_page(mapping, page); 3931da177e4SLinus Torvalds unlock_page(page); 3941da177e4SLinus Torvalds } 3950cd6144aSJohannes Weiner pagevec_remove_exceptionals(&pvec); 3961da177e4SLinus Torvalds pagevec_release(&pvec); 397569b846dSKAMEZAWA Hiroyuki mem_cgroup_uncharge_end(); 398b85e0effSHugh Dickins index++; 3991da177e4SLinus Torvalds } 4003167760fSDan Magenheimer cleancache_invalidate_inode(mapping); 4011da177e4SLinus Torvalds } 402d7339071SHans Reiser EXPORT_SYMBOL(truncate_inode_pages_range); 4031da177e4SLinus Torvalds 404d7339071SHans Reiser /** 405d7339071SHans Reiser * truncate_inode_pages - truncate *all* the pages from an offset 406d7339071SHans Reiser * @mapping: mapping to truncate 407d7339071SHans Reiser * @lstart: offset from which to truncate 408d7339071SHans Reiser * 4091b1dcc1bSJes Sorensen * Called under (and serialised by) inode->i_mutex. 41008142579SJan Kara * 41108142579SJan Kara * Note: When this function returns, there can be a page in the process of 41208142579SJan Kara * deletion (inside __delete_from_page_cache()) in the specified range. Thus 41308142579SJan Kara * mapping->nrpages can be non-zero when this function returns even after 41408142579SJan Kara * truncation of the whole mapping. 415d7339071SHans Reiser */ 416d7339071SHans Reiser void truncate_inode_pages(struct address_space *mapping, loff_t lstart) 417d7339071SHans Reiser { 418d7339071SHans Reiser truncate_inode_pages_range(mapping, lstart, (loff_t)-1); 419d7339071SHans Reiser } 4201da177e4SLinus Torvalds EXPORT_SYMBOL(truncate_inode_pages); 4211da177e4SLinus Torvalds 42228697355SMike Waychison /** 42391b0abe3SJohannes Weiner * truncate_inode_pages_final - truncate *all* pages before inode dies 42491b0abe3SJohannes Weiner * @mapping: mapping to truncate 42591b0abe3SJohannes Weiner * 42691b0abe3SJohannes Weiner * Called under (and serialized by) inode->i_mutex. 42791b0abe3SJohannes Weiner * 42891b0abe3SJohannes Weiner * Filesystems have to use this in the .evict_inode path to inform the 42991b0abe3SJohannes Weiner * VM that this is the final truncate and the inode is going away. 43091b0abe3SJohannes Weiner */ 43191b0abe3SJohannes Weiner void truncate_inode_pages_final(struct address_space *mapping) 43291b0abe3SJohannes Weiner { 43391b0abe3SJohannes Weiner unsigned long nrshadows; 43491b0abe3SJohannes Weiner unsigned long nrpages; 43591b0abe3SJohannes Weiner 43691b0abe3SJohannes Weiner /* 43791b0abe3SJohannes Weiner * Page reclaim can not participate in regular inode lifetime 43891b0abe3SJohannes Weiner * management (can't call iput()) and thus can race with the 43991b0abe3SJohannes Weiner * inode teardown. Tell it when the address space is exiting, 44091b0abe3SJohannes Weiner * so that it does not install eviction information after the 44191b0abe3SJohannes Weiner * final truncate has begun. 44291b0abe3SJohannes Weiner */ 44391b0abe3SJohannes Weiner mapping_set_exiting(mapping); 44491b0abe3SJohannes Weiner 44591b0abe3SJohannes Weiner /* 44691b0abe3SJohannes Weiner * When reclaim installs eviction entries, it increases 44791b0abe3SJohannes Weiner * nrshadows first, then decreases nrpages. Make sure we see 44891b0abe3SJohannes Weiner * this in the right order or we might miss an entry. 44991b0abe3SJohannes Weiner */ 45091b0abe3SJohannes Weiner nrpages = mapping->nrpages; 45191b0abe3SJohannes Weiner smp_rmb(); 45291b0abe3SJohannes Weiner nrshadows = mapping->nrshadows; 45391b0abe3SJohannes Weiner 45491b0abe3SJohannes Weiner if (nrpages || nrshadows) { 45591b0abe3SJohannes Weiner /* 45691b0abe3SJohannes Weiner * As truncation uses a lockless tree lookup, cycle 45791b0abe3SJohannes Weiner * the tree lock to make sure any ongoing tree 45891b0abe3SJohannes Weiner * modification that does not see AS_EXITING is 45991b0abe3SJohannes Weiner * completed before starting the final truncate. 46091b0abe3SJohannes Weiner */ 46191b0abe3SJohannes Weiner spin_lock_irq(&mapping->tree_lock); 46291b0abe3SJohannes Weiner spin_unlock_irq(&mapping->tree_lock); 46391b0abe3SJohannes Weiner 46491b0abe3SJohannes Weiner truncate_inode_pages(mapping, 0); 46591b0abe3SJohannes Weiner } 46691b0abe3SJohannes Weiner } 46791b0abe3SJohannes Weiner EXPORT_SYMBOL(truncate_inode_pages_final); 46891b0abe3SJohannes Weiner 46991b0abe3SJohannes Weiner /** 47028697355SMike Waychison * invalidate_mapping_pages - Invalidate all the unlocked pages of one inode 47128697355SMike Waychison * @mapping: the address_space which holds the pages to invalidate 47228697355SMike Waychison * @start: the offset 'from' which to invalidate 47328697355SMike Waychison * @end: the offset 'to' which to invalidate (inclusive) 47428697355SMike Waychison * 47528697355SMike Waychison * This function only removes the unlocked pages, if you want to 47628697355SMike Waychison * remove all the pages of one inode, you must call truncate_inode_pages. 47728697355SMike Waychison * 47828697355SMike Waychison * invalidate_mapping_pages() will not block on IO activity. It will not 47928697355SMike Waychison * invalidate pages which are dirty, locked, under writeback or mapped into 48028697355SMike Waychison * pagetables. 48128697355SMike Waychison */ 48228697355SMike Waychison unsigned long invalidate_mapping_pages(struct address_space *mapping, 48328697355SMike Waychison pgoff_t start, pgoff_t end) 4841da177e4SLinus Torvalds { 4850cd6144aSJohannes Weiner pgoff_t indices[PAGEVEC_SIZE]; 4861da177e4SLinus Torvalds struct pagevec pvec; 487b85e0effSHugh Dickins pgoff_t index = start; 48831560180SMinchan Kim unsigned long ret; 48931560180SMinchan Kim unsigned long count = 0; 4901da177e4SLinus Torvalds int i; 4911da177e4SLinus Torvalds 4921da177e4SLinus Torvalds pagevec_init(&pvec, 0); 4930cd6144aSJohannes Weiner while (index <= end && pagevec_lookup_entries(&pvec, mapping, index, 4940cd6144aSJohannes Weiner min(end - index, (pgoff_t)PAGEVEC_SIZE - 1) + 1, 4950cd6144aSJohannes Weiner indices)) { 496569b846dSKAMEZAWA Hiroyuki mem_cgroup_uncharge_start(); 4971da177e4SLinus Torvalds for (i = 0; i < pagevec_count(&pvec); i++) { 4981da177e4SLinus Torvalds struct page *page = pvec.pages[i]; 4991da177e4SLinus Torvalds 500b85e0effSHugh Dickins /* We rely upon deletion not changing page->index */ 5010cd6144aSJohannes Weiner index = indices[i]; 502b85e0effSHugh Dickins if (index > end) 503b85e0effSHugh Dickins break; 504e0f23603SNeilBrown 5050cd6144aSJohannes Weiner if (radix_tree_exceptional_entry(page)) { 5060cd6144aSJohannes Weiner clear_exceptional_entry(mapping, index, page); 5070cd6144aSJohannes Weiner continue; 5080cd6144aSJohannes Weiner } 5090cd6144aSJohannes Weiner 510b85e0effSHugh Dickins if (!trylock_page(page)) 511b85e0effSHugh Dickins continue; 512b85e0effSHugh Dickins WARN_ON(page->index != index); 51331560180SMinchan Kim ret = invalidate_inode_page(page); 5141da177e4SLinus Torvalds unlock_page(page); 51531560180SMinchan Kim /* 51631560180SMinchan Kim * Invalidation is a hint that the page is no longer 51731560180SMinchan Kim * of interest and try to speed up its reclaim. 51831560180SMinchan Kim */ 51931560180SMinchan Kim if (!ret) 52031560180SMinchan Kim deactivate_page(page); 52131560180SMinchan Kim count += ret; 5221da177e4SLinus Torvalds } 5230cd6144aSJohannes Weiner pagevec_remove_exceptionals(&pvec); 5241da177e4SLinus Torvalds pagevec_release(&pvec); 525569b846dSKAMEZAWA Hiroyuki mem_cgroup_uncharge_end(); 526fc9a07e7SAndrew Morton cond_resched(); 527b85e0effSHugh Dickins index++; 5281da177e4SLinus Torvalds } 52931560180SMinchan Kim return count; 5301da177e4SLinus Torvalds } 53154bc4855SAnton Altaparmakov EXPORT_SYMBOL(invalidate_mapping_pages); 5321da177e4SLinus Torvalds 533bd4c8ce4SAndrew Morton /* 534bd4c8ce4SAndrew Morton * This is like invalidate_complete_page(), except it ignores the page's 535bd4c8ce4SAndrew Morton * refcount. We do this because invalidate_inode_pages2() needs stronger 536bd4c8ce4SAndrew Morton * invalidation guarantees, and cannot afford to leave pages behind because 5372706a1b8SAnderson Briglia * shrink_page_list() has a temp ref on them, or because they're transiently 5382706a1b8SAnderson Briglia * sitting in the lru_cache_add() pagevecs. 539bd4c8ce4SAndrew Morton */ 540bd4c8ce4SAndrew Morton static int 541bd4c8ce4SAndrew Morton invalidate_complete_page2(struct address_space *mapping, struct page *page) 542bd4c8ce4SAndrew Morton { 543bd4c8ce4SAndrew Morton if (page->mapping != mapping) 544bd4c8ce4SAndrew Morton return 0; 545bd4c8ce4SAndrew Morton 546266cf658SDavid Howells if (page_has_private(page) && !try_to_release_page(page, GFP_KERNEL)) 547bd4c8ce4SAndrew Morton return 0; 548bd4c8ce4SAndrew Morton 54919fd6231SNick Piggin spin_lock_irq(&mapping->tree_lock); 550bd4c8ce4SAndrew Morton if (PageDirty(page)) 551bd4c8ce4SAndrew Morton goto failed; 552bd4c8ce4SAndrew Morton 553266cf658SDavid Howells BUG_ON(page_has_private(page)); 55491b0abe3SJohannes Weiner __delete_from_page_cache(page, NULL); 55519fd6231SNick Piggin spin_unlock_irq(&mapping->tree_lock); 556e767e056SDaisuke Nishimura mem_cgroup_uncharge_cache_page(page); 5576072d13cSLinus Torvalds 5586072d13cSLinus Torvalds if (mapping->a_ops->freepage) 5596072d13cSLinus Torvalds mapping->a_ops->freepage(page); 5606072d13cSLinus Torvalds 561bd4c8ce4SAndrew Morton page_cache_release(page); /* pagecache ref */ 562bd4c8ce4SAndrew Morton return 1; 563bd4c8ce4SAndrew Morton failed: 56419fd6231SNick Piggin spin_unlock_irq(&mapping->tree_lock); 565bd4c8ce4SAndrew Morton return 0; 566bd4c8ce4SAndrew Morton } 567bd4c8ce4SAndrew Morton 568e3db7691STrond Myklebust static int do_launder_page(struct address_space *mapping, struct page *page) 569e3db7691STrond Myklebust { 570e3db7691STrond Myklebust if (!PageDirty(page)) 571e3db7691STrond Myklebust return 0; 572e3db7691STrond Myklebust if (page->mapping != mapping || mapping->a_ops->launder_page == NULL) 573e3db7691STrond Myklebust return 0; 574e3db7691STrond Myklebust return mapping->a_ops->launder_page(page); 575e3db7691STrond Myklebust } 576e3db7691STrond Myklebust 5771da177e4SLinus Torvalds /** 5781da177e4SLinus Torvalds * invalidate_inode_pages2_range - remove range of pages from an address_space 57967be2dd1SMartin Waitz * @mapping: the address_space 5801da177e4SLinus Torvalds * @start: the page offset 'from' which to invalidate 5811da177e4SLinus Torvalds * @end: the page offset 'to' which to invalidate (inclusive) 5821da177e4SLinus Torvalds * 5831da177e4SLinus Torvalds * Any pages which are found to be mapped into pagetables are unmapped prior to 5841da177e4SLinus Torvalds * invalidation. 5851da177e4SLinus Torvalds * 5866ccfa806SHisashi Hifumi * Returns -EBUSY if any pages could not be invalidated. 5871da177e4SLinus Torvalds */ 5881da177e4SLinus Torvalds int invalidate_inode_pages2_range(struct address_space *mapping, 5891da177e4SLinus Torvalds pgoff_t start, pgoff_t end) 5901da177e4SLinus Torvalds { 5910cd6144aSJohannes Weiner pgoff_t indices[PAGEVEC_SIZE]; 5921da177e4SLinus Torvalds struct pagevec pvec; 593b85e0effSHugh Dickins pgoff_t index; 5941da177e4SLinus Torvalds int i; 5951da177e4SLinus Torvalds int ret = 0; 5960dd1334fSHisashi Hifumi int ret2 = 0; 5971da177e4SLinus Torvalds int did_range_unmap = 0; 5981da177e4SLinus Torvalds 5993167760fSDan Magenheimer cleancache_invalidate_inode(mapping); 6001da177e4SLinus Torvalds pagevec_init(&pvec, 0); 601b85e0effSHugh Dickins index = start; 6020cd6144aSJohannes Weiner while (index <= end && pagevec_lookup_entries(&pvec, mapping, index, 6030cd6144aSJohannes Weiner min(end - index, (pgoff_t)PAGEVEC_SIZE - 1) + 1, 6040cd6144aSJohannes Weiner indices)) { 605569b846dSKAMEZAWA Hiroyuki mem_cgroup_uncharge_start(); 6067b965e08STrond Myklebust for (i = 0; i < pagevec_count(&pvec); i++) { 6071da177e4SLinus Torvalds struct page *page = pvec.pages[i]; 608b85e0effSHugh Dickins 609b85e0effSHugh Dickins /* We rely upon deletion not changing page->index */ 6100cd6144aSJohannes Weiner index = indices[i]; 611b85e0effSHugh Dickins if (index > end) 612b85e0effSHugh Dickins break; 6131da177e4SLinus Torvalds 6140cd6144aSJohannes Weiner if (radix_tree_exceptional_entry(page)) { 6150cd6144aSJohannes Weiner clear_exceptional_entry(mapping, index, page); 6160cd6144aSJohannes Weiner continue; 6170cd6144aSJohannes Weiner } 6180cd6144aSJohannes Weiner 6191da177e4SLinus Torvalds lock_page(page); 620b85e0effSHugh Dickins WARN_ON(page->index != index); 6211da177e4SLinus Torvalds if (page->mapping != mapping) { 6221da177e4SLinus Torvalds unlock_page(page); 6231da177e4SLinus Torvalds continue; 6241da177e4SLinus Torvalds } 6251da177e4SLinus Torvalds wait_on_page_writeback(page); 626d00806b1SNick Piggin if (page_mapped(page)) { 6271da177e4SLinus Torvalds if (!did_range_unmap) { 6281da177e4SLinus Torvalds /* 6291da177e4SLinus Torvalds * Zap the rest of the file in one hit. 6301da177e4SLinus Torvalds */ 6311da177e4SLinus Torvalds unmap_mapping_range(mapping, 632b85e0effSHugh Dickins (loff_t)index << PAGE_CACHE_SHIFT, 633b85e0effSHugh Dickins (loff_t)(1 + end - index) 6341da177e4SLinus Torvalds << PAGE_CACHE_SHIFT, 6351da177e4SLinus Torvalds 0); 6361da177e4SLinus Torvalds did_range_unmap = 1; 6371da177e4SLinus Torvalds } else { 6381da177e4SLinus Torvalds /* 6391da177e4SLinus Torvalds * Just zap this page 6401da177e4SLinus Torvalds */ 6411da177e4SLinus Torvalds unmap_mapping_range(mapping, 642b85e0effSHugh Dickins (loff_t)index << PAGE_CACHE_SHIFT, 6431da177e4SLinus Torvalds PAGE_CACHE_SIZE, 0); 6441da177e4SLinus Torvalds } 6451da177e4SLinus Torvalds } 646d00806b1SNick Piggin BUG_ON(page_mapped(page)); 6470dd1334fSHisashi Hifumi ret2 = do_launder_page(mapping, page); 6480dd1334fSHisashi Hifumi if (ret2 == 0) { 6490dd1334fSHisashi Hifumi if (!invalidate_complete_page2(mapping, page)) 6506ccfa806SHisashi Hifumi ret2 = -EBUSY; 6510dd1334fSHisashi Hifumi } 6520dd1334fSHisashi Hifumi if (ret2 < 0) 6530dd1334fSHisashi Hifumi ret = ret2; 6541da177e4SLinus Torvalds unlock_page(page); 6551da177e4SLinus Torvalds } 6560cd6144aSJohannes Weiner pagevec_remove_exceptionals(&pvec); 6571da177e4SLinus Torvalds pagevec_release(&pvec); 658569b846dSKAMEZAWA Hiroyuki mem_cgroup_uncharge_end(); 6591da177e4SLinus Torvalds cond_resched(); 660b85e0effSHugh Dickins index++; 6611da177e4SLinus Torvalds } 6623167760fSDan Magenheimer cleancache_invalidate_inode(mapping); 6631da177e4SLinus Torvalds return ret; 6641da177e4SLinus Torvalds } 6651da177e4SLinus Torvalds EXPORT_SYMBOL_GPL(invalidate_inode_pages2_range); 6661da177e4SLinus Torvalds 6671da177e4SLinus Torvalds /** 6681da177e4SLinus Torvalds * invalidate_inode_pages2 - remove all pages from an address_space 66967be2dd1SMartin Waitz * @mapping: the address_space 6701da177e4SLinus Torvalds * 6711da177e4SLinus Torvalds * Any pages which are found to be mapped into pagetables are unmapped prior to 6721da177e4SLinus Torvalds * invalidation. 6731da177e4SLinus Torvalds * 674e9de25ddSPeng Tao * Returns -EBUSY if any pages could not be invalidated. 6751da177e4SLinus Torvalds */ 6761da177e4SLinus Torvalds int invalidate_inode_pages2(struct address_space *mapping) 6771da177e4SLinus Torvalds { 6781da177e4SLinus Torvalds return invalidate_inode_pages2_range(mapping, 0, -1); 6791da177e4SLinus Torvalds } 6801da177e4SLinus Torvalds EXPORT_SYMBOL_GPL(invalidate_inode_pages2); 68125d9e2d1Snpiggin@suse.de 68225d9e2d1Snpiggin@suse.de /** 68325d9e2d1Snpiggin@suse.de * truncate_pagecache - unmap and remove pagecache that has been truncated 68425d9e2d1Snpiggin@suse.de * @inode: inode 6858a549beaSHugh Dickins * @newsize: new file size 68625d9e2d1Snpiggin@suse.de * 68725d9e2d1Snpiggin@suse.de * inode's new i_size must already be written before truncate_pagecache 68825d9e2d1Snpiggin@suse.de * is called. 68925d9e2d1Snpiggin@suse.de * 69025d9e2d1Snpiggin@suse.de * This function should typically be called before the filesystem 69125d9e2d1Snpiggin@suse.de * releases resources associated with the freed range (eg. deallocates 69225d9e2d1Snpiggin@suse.de * blocks). This way, pagecache will always stay logically coherent 69325d9e2d1Snpiggin@suse.de * with on-disk format, and the filesystem would not have to deal with 69425d9e2d1Snpiggin@suse.de * situations such as writepage being called for a page that has already 69525d9e2d1Snpiggin@suse.de * had its underlying blocks deallocated. 69625d9e2d1Snpiggin@suse.de */ 6977caef267SKirill A. Shutemov void truncate_pagecache(struct inode *inode, loff_t newsize) 69825d9e2d1Snpiggin@suse.de { 69925d9e2d1Snpiggin@suse.de struct address_space *mapping = inode->i_mapping; 7008a549beaSHugh Dickins loff_t holebegin = round_up(newsize, PAGE_SIZE); 70125d9e2d1Snpiggin@suse.de 70225d9e2d1Snpiggin@suse.de /* 70325d9e2d1Snpiggin@suse.de * unmap_mapping_range is called twice, first simply for 70425d9e2d1Snpiggin@suse.de * efficiency so that truncate_inode_pages does fewer 70525d9e2d1Snpiggin@suse.de * single-page unmaps. However after this first call, and 70625d9e2d1Snpiggin@suse.de * before truncate_inode_pages finishes, it is possible for 70725d9e2d1Snpiggin@suse.de * private pages to be COWed, which remain after 70825d9e2d1Snpiggin@suse.de * truncate_inode_pages finishes, hence the second 70925d9e2d1Snpiggin@suse.de * unmap_mapping_range call must be made for correctness. 71025d9e2d1Snpiggin@suse.de */ 7118a549beaSHugh Dickins unmap_mapping_range(mapping, holebegin, 0, 1); 7128a549beaSHugh Dickins truncate_inode_pages(mapping, newsize); 7138a549beaSHugh Dickins unmap_mapping_range(mapping, holebegin, 0, 1); 71425d9e2d1Snpiggin@suse.de } 71525d9e2d1Snpiggin@suse.de EXPORT_SYMBOL(truncate_pagecache); 71625d9e2d1Snpiggin@suse.de 71725d9e2d1Snpiggin@suse.de /** 7182c27c65eSChristoph Hellwig * truncate_setsize - update inode and pagecache for a new file size 7192c27c65eSChristoph Hellwig * @inode: inode 7202c27c65eSChristoph Hellwig * @newsize: new file size 7212c27c65eSChristoph Hellwig * 722382e27daSJan Kara * truncate_setsize updates i_size and performs pagecache truncation (if 723382e27daSJan Kara * necessary) to @newsize. It will be typically be called from the filesystem's 724382e27daSJan Kara * setattr function when ATTR_SIZE is passed in. 7252c27c65eSChristoph Hellwig * 726382e27daSJan Kara * Must be called with inode_mutex held and before all filesystem specific 727382e27daSJan Kara * block truncation has been performed. 7282c27c65eSChristoph Hellwig */ 7292c27c65eSChristoph Hellwig void truncate_setsize(struct inode *inode, loff_t newsize) 7302c27c65eSChristoph Hellwig { 7312c27c65eSChristoph Hellwig i_size_write(inode, newsize); 7327caef267SKirill A. Shutemov truncate_pagecache(inode, newsize); 7332c27c65eSChristoph Hellwig } 7342c27c65eSChristoph Hellwig EXPORT_SYMBOL(truncate_setsize); 7352c27c65eSChristoph Hellwig 7362c27c65eSChristoph Hellwig /** 737623e3db9SHugh Dickins * truncate_pagecache_range - unmap and remove pagecache that is hole-punched 738623e3db9SHugh Dickins * @inode: inode 739623e3db9SHugh Dickins * @lstart: offset of beginning of hole 740623e3db9SHugh Dickins * @lend: offset of last byte of hole 741623e3db9SHugh Dickins * 742623e3db9SHugh Dickins * This function should typically be called before the filesystem 743623e3db9SHugh Dickins * releases resources associated with the freed range (eg. deallocates 744623e3db9SHugh Dickins * blocks). This way, pagecache will always stay logically coherent 745623e3db9SHugh Dickins * with on-disk format, and the filesystem would not have to deal with 746623e3db9SHugh Dickins * situations such as writepage being called for a page that has already 747623e3db9SHugh Dickins * had its underlying blocks deallocated. 748623e3db9SHugh Dickins */ 749623e3db9SHugh Dickins void truncate_pagecache_range(struct inode *inode, loff_t lstart, loff_t lend) 750623e3db9SHugh Dickins { 751623e3db9SHugh Dickins struct address_space *mapping = inode->i_mapping; 752623e3db9SHugh Dickins loff_t unmap_start = round_up(lstart, PAGE_SIZE); 753623e3db9SHugh Dickins loff_t unmap_end = round_down(1 + lend, PAGE_SIZE) - 1; 754623e3db9SHugh Dickins /* 755623e3db9SHugh Dickins * This rounding is currently just for example: unmap_mapping_range 756623e3db9SHugh Dickins * expands its hole outwards, whereas we want it to contract the hole 757623e3db9SHugh Dickins * inwards. However, existing callers of truncate_pagecache_range are 7585a720394SLukas Czerner * doing their own page rounding first. Note that unmap_mapping_range 7595a720394SLukas Czerner * allows holelen 0 for all, and we allow lend -1 for end of file. 760623e3db9SHugh Dickins */ 761623e3db9SHugh Dickins 762623e3db9SHugh Dickins /* 763623e3db9SHugh Dickins * Unlike in truncate_pagecache, unmap_mapping_range is called only 764623e3db9SHugh Dickins * once (before truncating pagecache), and without "even_cows" flag: 765623e3db9SHugh Dickins * hole-punching should not remove private COWed pages from the hole. 766623e3db9SHugh Dickins */ 767623e3db9SHugh Dickins if ((u64)unmap_end > (u64)unmap_start) 768623e3db9SHugh Dickins unmap_mapping_range(mapping, unmap_start, 769623e3db9SHugh Dickins 1 + unmap_end - unmap_start, 0); 770623e3db9SHugh Dickins truncate_inode_pages_range(mapping, lstart, lend); 771623e3db9SHugh Dickins } 772623e3db9SHugh Dickins EXPORT_SYMBOL(truncate_pagecache_range); 773