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869 lines
26 KiB
869 lines
26 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* mm/truncate.c - code for taking down pages from address_spaces |
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* |
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* Copyright (C) 2002, Linus Torvalds |
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* |
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* 10Sep2002 Andrew Morton |
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* Initial version. |
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*/ |
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|
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#include <linux/kernel.h> |
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#include <linux/backing-dev.h> |
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#include <linux/dax.h> |
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#include <linux/gfp.h> |
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#include <linux/mm.h> |
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#include <linux/swap.h> |
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#include <linux/export.h> |
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#include <linux/pagemap.h> |
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#include <linux/highmem.h> |
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#include <linux/pagevec.h> |
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#include <linux/task_io_accounting_ops.h> |
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#include <linux/buffer_head.h> /* grr. try_to_release_page */ |
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#include <linux/shmem_fs.h> |
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#include <linux/rmap.h> |
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#include "internal.h" |
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|
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/* |
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* Regular page slots are stabilized by the page lock even without the tree |
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* itself locked. These unlocked entries need verification under the tree |
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* lock. |
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*/ |
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static inline void __clear_shadow_entry(struct address_space *mapping, |
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pgoff_t index, void *entry) |
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{ |
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XA_STATE(xas, &mapping->i_pages, index); |
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|
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xas_set_update(&xas, workingset_update_node); |
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if (xas_load(&xas) != entry) |
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return; |
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xas_store(&xas, NULL); |
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} |
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|
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static void clear_shadow_entry(struct address_space *mapping, pgoff_t index, |
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void *entry) |
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{ |
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spin_lock(&mapping->host->i_lock); |
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xa_lock_irq(&mapping->i_pages); |
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__clear_shadow_entry(mapping, index, entry); |
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xa_unlock_irq(&mapping->i_pages); |
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if (mapping_shrinkable(mapping)) |
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inode_add_lru(mapping->host); |
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spin_unlock(&mapping->host->i_lock); |
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} |
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|
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/* |
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* Unconditionally remove exceptional entries. Usually called from truncate |
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* path. Note that the folio_batch may be altered by this function by removing |
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* exceptional entries similar to what folio_batch_remove_exceptionals() does. |
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*/ |
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static void truncate_folio_batch_exceptionals(struct address_space *mapping, |
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struct folio_batch *fbatch, pgoff_t *indices) |
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{ |
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int i, j; |
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bool dax; |
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|
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/* Handled by shmem itself */ |
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if (shmem_mapping(mapping)) |
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return; |
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|
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for (j = 0; j < folio_batch_count(fbatch); j++) |
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if (xa_is_value(fbatch->folios[j])) |
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break; |
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|
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if (j == folio_batch_count(fbatch)) |
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return; |
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|
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dax = dax_mapping(mapping); |
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if (!dax) { |
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spin_lock(&mapping->host->i_lock); |
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xa_lock_irq(&mapping->i_pages); |
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} |
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|
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for (i = j; i < folio_batch_count(fbatch); i++) { |
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struct folio *folio = fbatch->folios[i]; |
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pgoff_t index = indices[i]; |
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|
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if (!xa_is_value(folio)) { |
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fbatch->folios[j++] = folio; |
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continue; |
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} |
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|
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if (unlikely(dax)) { |
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dax_delete_mapping_entry(mapping, index); |
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continue; |
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} |
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|
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__clear_shadow_entry(mapping, index, folio); |
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} |
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|
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if (!dax) { |
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xa_unlock_irq(&mapping->i_pages); |
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if (mapping_shrinkable(mapping)) |
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inode_add_lru(mapping->host); |
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spin_unlock(&mapping->host->i_lock); |
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} |
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fbatch->nr = j; |
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} |
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|
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/* |
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* Invalidate exceptional entry if easily possible. This handles exceptional |
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* entries for invalidate_inode_pages(). |
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*/ |
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static int invalidate_exceptional_entry(struct address_space *mapping, |
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pgoff_t index, void *entry) |
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{ |
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/* Handled by shmem itself, or for DAX we do nothing. */ |
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if (shmem_mapping(mapping) || dax_mapping(mapping)) |
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return 1; |
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clear_shadow_entry(mapping, index, entry); |
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return 1; |
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} |
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|
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/* |
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* Invalidate exceptional entry if clean. This handles exceptional entries for |
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* invalidate_inode_pages2() so for DAX it evicts only clean entries. |
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*/ |
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static int invalidate_exceptional_entry2(struct address_space *mapping, |
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pgoff_t index, void *entry) |
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{ |
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/* Handled by shmem itself */ |
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if (shmem_mapping(mapping)) |
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return 1; |
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if (dax_mapping(mapping)) |
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return dax_invalidate_mapping_entry_sync(mapping, index); |
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clear_shadow_entry(mapping, index, entry); |
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return 1; |
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} |
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|
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/** |
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* folio_invalidate - Invalidate part or all of a folio. |
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* @folio: The folio which is affected. |
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* @offset: start of the range to invalidate |
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* @length: length of the range to invalidate |
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* |
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* folio_invalidate() is called when all or part of the folio has become |
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* invalidated by a truncate operation. |
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* |
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* folio_invalidate() does not have to release all buffers, but it must |
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* ensure that no dirty buffer is left outside @offset and that no I/O |
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* is underway against any of the blocks which are outside the truncation |
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* point. Because the caller is about to free (and possibly reuse) those |
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* blocks on-disk. |
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*/ |
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void folio_invalidate(struct folio *folio, size_t offset, size_t length) |
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{ |
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const struct address_space_operations *aops = folio->mapping->a_ops; |
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|
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if (aops->invalidate_folio) |
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aops->invalidate_folio(folio, offset, length); |
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} |
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EXPORT_SYMBOL_GPL(folio_invalidate); |
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|
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/* |
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* If truncate cannot remove the fs-private metadata from the page, the page |
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* becomes orphaned. It will be left on the LRU and may even be mapped into |
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* user pagetables if we're racing with filemap_fault(). |
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* |
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* We need to bail out if page->mapping is no longer equal to the original |
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* mapping. This happens a) when the VM reclaimed the page while we waited on |
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* its lock, b) when a concurrent invalidate_mapping_pages got there first and |
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* c) when tmpfs swizzles a page between a tmpfs inode and swapper_space. |
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*/ |
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static void truncate_cleanup_folio(struct folio *folio) |
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{ |
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if (folio_mapped(folio)) |
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unmap_mapping_folio(folio); |
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|
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if (folio_has_private(folio)) |
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folio_invalidate(folio, 0, folio_size(folio)); |
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|
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/* |
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* Some filesystems seem to re-dirty the page even after |
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* the VM has canceled the dirty bit (eg ext3 journaling). |
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* Hence dirty accounting check is placed after invalidation. |
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*/ |
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folio_cancel_dirty(folio); |
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folio_clear_mappedtodisk(folio); |
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} |
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|
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int truncate_inode_folio(struct address_space *mapping, struct folio *folio) |
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{ |
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if (folio->mapping != mapping) |
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return -EIO; |
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|
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truncate_cleanup_folio(folio); |
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filemap_remove_folio(folio); |
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return 0; |
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} |
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|
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/* |
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* Handle partial folios. The folio may be entirely within the |
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* range if a split has raced with us. If not, we zero the part of the |
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* folio that's within the [start, end] range, and then split the folio if |
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* it's large. split_page_range() will discard pages which now lie beyond |
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* i_size, and we rely on the caller to discard pages which lie within a |
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* newly created hole. |
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* |
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* Returns false if splitting failed so the caller can avoid |
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* discarding the entire folio which is stubbornly unsplit. |
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*/ |
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bool truncate_inode_partial_folio(struct folio *folio, loff_t start, loff_t end) |
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{ |
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loff_t pos = folio_pos(folio); |
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unsigned int offset, length; |
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|
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if (pos < start) |
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offset = start - pos; |
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else |
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offset = 0; |
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length = folio_size(folio); |
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if (pos + length <= (u64)end) |
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length = length - offset; |
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else |
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length = end + 1 - pos - offset; |
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folio_wait_writeback(folio); |
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if (length == folio_size(folio)) { |
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truncate_inode_folio(folio->mapping, folio); |
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return true; |
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} |
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|
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/* |
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* We may be zeroing pages we're about to discard, but it avoids |
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* doing a complex calculation here, and then doing the zeroing |
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* anyway if the page split fails. |
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*/ |
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folio_zero_range(folio, offset, length); |
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|
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if (folio_has_private(folio)) |
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folio_invalidate(folio, offset, length); |
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if (!folio_test_large(folio)) |
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return true; |
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if (split_folio(folio) == 0) |
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return true; |
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if (folio_test_dirty(folio)) |
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return false; |
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truncate_inode_folio(folio->mapping, folio); |
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return true; |
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} |
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|
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/* |
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* Used to get rid of pages on hardware memory corruption. |
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*/ |
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int generic_error_remove_page(struct address_space *mapping, struct page *page) |
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{ |
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VM_BUG_ON_PAGE(PageTail(page), page); |
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|
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if (!mapping) |
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return -EINVAL; |
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/* |
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* Only punch for normal data pages for now. |
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* Handling other types like directories would need more auditing. |
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*/ |
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if (!S_ISREG(mapping->host->i_mode)) |
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return -EIO; |
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return truncate_inode_folio(mapping, page_folio(page)); |
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} |
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EXPORT_SYMBOL(generic_error_remove_page); |
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|
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static long mapping_evict_folio(struct address_space *mapping, |
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struct folio *folio) |
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{ |
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if (folio_test_dirty(folio) || folio_test_writeback(folio)) |
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return 0; |
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/* The refcount will be elevated if any page in the folio is mapped */ |
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if (folio_ref_count(folio) > |
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folio_nr_pages(folio) + folio_has_private(folio) + 1) |
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return 0; |
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if (folio_has_private(folio) && !filemap_release_folio(folio, 0)) |
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return 0; |
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|
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return remove_mapping(mapping, folio); |
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} |
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|
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/** |
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* invalidate_inode_page() - Remove an unused page from the pagecache. |
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* @page: The page to remove. |
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* |
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* Safely invalidate one page from its pagecache mapping. |
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* It only drops clean, unused pages. |
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* |
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* Context: Page must be locked. |
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* Return: The number of pages successfully removed. |
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*/ |
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long invalidate_inode_page(struct page *page) |
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{ |
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struct folio *folio = page_folio(page); |
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struct address_space *mapping = folio_mapping(folio); |
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|
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/* The page may have been truncated before it was locked */ |
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if (!mapping) |
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return 0; |
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return mapping_evict_folio(mapping, folio); |
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} |
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|
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/** |
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* truncate_inode_pages_range - truncate range of pages specified by start & end byte offsets |
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* @mapping: mapping to truncate |
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* @lstart: offset from which to truncate |
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* @lend: offset to which to truncate (inclusive) |
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* |
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* Truncate the page cache, removing the pages that are between |
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* specified offsets (and zeroing out partial pages |
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* if lstart or lend + 1 is not page aligned). |
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* |
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* Truncate takes two passes - the first pass is nonblocking. It will not |
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* block on page locks and it will not block on writeback. The second pass |
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* will wait. This is to prevent as much IO as possible in the affected region. |
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* The first pass will remove most pages, so the search cost of the second pass |
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* is low. |
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* |
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* We pass down the cache-hot hint to the page freeing code. Even if the |
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* mapping is large, it is probably the case that the final pages are the most |
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* recently touched, and freeing happens in ascending file offset order. |
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* |
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* Note that since ->invalidate_folio() accepts range to invalidate |
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* truncate_inode_pages_range is able to handle cases where lend + 1 is not |
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* page aligned properly. |
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*/ |
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void truncate_inode_pages_range(struct address_space *mapping, |
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loff_t lstart, loff_t lend) |
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{ |
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pgoff_t start; /* inclusive */ |
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pgoff_t end; /* exclusive */ |
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struct folio_batch fbatch; |
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pgoff_t indices[PAGEVEC_SIZE]; |
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pgoff_t index; |
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int i; |
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struct folio *folio; |
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bool same_folio; |
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|
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if (mapping_empty(mapping)) |
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return; |
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|
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/* |
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* 'start' and 'end' always covers the range of pages to be fully |
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* truncated. Partial pages are covered with 'partial_start' at the |
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* start of the range and 'partial_end' at the end of the range. |
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* Note that 'end' is exclusive while 'lend' is inclusive. |
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*/ |
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start = (lstart + PAGE_SIZE - 1) >> PAGE_SHIFT; |
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if (lend == -1) |
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/* |
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* lend == -1 indicates end-of-file so we have to set 'end' |
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* to the highest possible pgoff_t and since the type is |
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* unsigned we're using -1. |
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*/ |
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end = -1; |
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else |
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end = (lend + 1) >> PAGE_SHIFT; |
|
|
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folio_batch_init(&fbatch); |
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index = start; |
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while (index < end && find_lock_entries(mapping, index, end - 1, |
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&fbatch, indices)) { |
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index = indices[folio_batch_count(&fbatch) - 1] + 1; |
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truncate_folio_batch_exceptionals(mapping, &fbatch, indices); |
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for (i = 0; i < folio_batch_count(&fbatch); i++) |
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truncate_cleanup_folio(fbatch.folios[i]); |
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delete_from_page_cache_batch(mapping, &fbatch); |
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for (i = 0; i < folio_batch_count(&fbatch); i++) |
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folio_unlock(fbatch.folios[i]); |
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folio_batch_release(&fbatch); |
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cond_resched(); |
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} |
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|
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same_folio = (lstart >> PAGE_SHIFT) == (lend >> PAGE_SHIFT); |
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folio = __filemap_get_folio(mapping, lstart >> PAGE_SHIFT, FGP_LOCK, 0); |
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if (folio) { |
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same_folio = lend < folio_pos(folio) + folio_size(folio); |
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if (!truncate_inode_partial_folio(folio, lstart, lend)) { |
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start = folio->index + folio_nr_pages(folio); |
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if (same_folio) |
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end = folio->index; |
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} |
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folio_unlock(folio); |
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folio_put(folio); |
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folio = NULL; |
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} |
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|
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if (!same_folio) |
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folio = __filemap_get_folio(mapping, lend >> PAGE_SHIFT, |
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FGP_LOCK, 0); |
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if (folio) { |
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if (!truncate_inode_partial_folio(folio, lstart, lend)) |
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end = folio->index; |
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folio_unlock(folio); |
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folio_put(folio); |
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} |
|
|
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index = start; |
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while (index < end) { |
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cond_resched(); |
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if (!find_get_entries(mapping, index, end - 1, &fbatch, |
|
indices)) { |
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/* If all gone from start onwards, we're done */ |
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if (index == start) |
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break; |
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/* Otherwise restart to make sure all gone */ |
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index = start; |
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continue; |
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} |
|
|
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for (i = 0; i < folio_batch_count(&fbatch); i++) { |
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struct folio *folio = fbatch.folios[i]; |
|
|
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/* We rely upon deletion not changing page->index */ |
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index = indices[i]; |
|
|
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if (xa_is_value(folio)) |
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continue; |
|
|
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folio_lock(folio); |
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VM_BUG_ON_FOLIO(!folio_contains(folio, index), folio); |
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folio_wait_writeback(folio); |
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truncate_inode_folio(mapping, folio); |
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folio_unlock(folio); |
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index = folio_index(folio) + folio_nr_pages(folio) - 1; |
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} |
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truncate_folio_batch_exceptionals(mapping, &fbatch, indices); |
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folio_batch_release(&fbatch); |
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index++; |
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} |
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} |
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EXPORT_SYMBOL(truncate_inode_pages_range); |
|
|
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/** |
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* truncate_inode_pages - truncate *all* the pages from an offset |
|
* @mapping: mapping to truncate |
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* @lstart: offset from which to truncate |
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* |
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* Called under (and serialised by) inode->i_rwsem and |
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* mapping->invalidate_lock. |
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* |
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* Note: When this function returns, there can be a page in the process of |
|
* deletion (inside __filemap_remove_folio()) in the specified range. Thus |
|
* mapping->nrpages can be non-zero when this function returns even after |
|
* truncation of the whole mapping. |
|
*/ |
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void truncate_inode_pages(struct address_space *mapping, loff_t lstart) |
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{ |
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truncate_inode_pages_range(mapping, lstart, (loff_t)-1); |
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} |
|
EXPORT_SYMBOL(truncate_inode_pages); |
|
|
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/** |
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* truncate_inode_pages_final - truncate *all* pages before inode dies |
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* @mapping: mapping to truncate |
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* |
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* Called under (and serialized by) inode->i_rwsem. |
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* |
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* Filesystems have to use this in the .evict_inode path to inform the |
|
* VM that this is the final truncate and the inode is going away. |
|
*/ |
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void truncate_inode_pages_final(struct address_space *mapping) |
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{ |
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/* |
|
* Page reclaim can not participate in regular inode lifetime |
|
* management (can't call iput()) and thus can race with the |
|
* inode teardown. Tell it when the address space is exiting, |
|
* so that it does not install eviction information after the |
|
* final truncate has begun. |
|
*/ |
|
mapping_set_exiting(mapping); |
|
|
|
if (!mapping_empty(mapping)) { |
|
/* |
|
* As truncation uses a lockless tree lookup, cycle |
|
* the tree lock to make sure any ongoing tree |
|
* modification that does not see AS_EXITING is |
|
* completed before starting the final truncate. |
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*/ |
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xa_lock_irq(&mapping->i_pages); |
|
xa_unlock_irq(&mapping->i_pages); |
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} |
|
|
|
truncate_inode_pages(mapping, 0); |
|
} |
|
EXPORT_SYMBOL(truncate_inode_pages_final); |
|
|
|
/** |
|
* invalidate_mapping_pagevec - 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) |
|
* @nr_pagevec: invalidate failed page number for caller |
|
* |
|
* This helper is similar to invalidate_mapping_pages(), except that it accounts |
|
* for pages that are likely on a pagevec and counts them in @nr_pagevec, which |
|
* will be used by the caller. |
|
*/ |
|
unsigned long invalidate_mapping_pagevec(struct address_space *mapping, |
|
pgoff_t start, pgoff_t end, unsigned long *nr_pagevec) |
|
{ |
|
pgoff_t indices[PAGEVEC_SIZE]; |
|
struct folio_batch fbatch; |
|
pgoff_t index = start; |
|
unsigned long ret; |
|
unsigned long count = 0; |
|
int i; |
|
|
|
folio_batch_init(&fbatch); |
|
while (find_lock_entries(mapping, index, end, &fbatch, indices)) { |
|
for (i = 0; i < folio_batch_count(&fbatch); i++) { |
|
struct folio *folio = fbatch.folios[i]; |
|
|
|
/* We rely upon deletion not changing folio->index */ |
|
index = indices[i]; |
|
|
|
if (xa_is_value(folio)) { |
|
count += invalidate_exceptional_entry(mapping, |
|
index, |
|
folio); |
|
continue; |
|
} |
|
index += folio_nr_pages(folio) - 1; |
|
|
|
ret = mapping_evict_folio(mapping, folio); |
|
folio_unlock(folio); |
|
/* |
|
* Invalidation is a hint that the folio is no longer |
|
* of interest and try to speed up its reclaim. |
|
*/ |
|
if (!ret) { |
|
deactivate_file_folio(folio); |
|
/* It is likely on the pagevec of a remote CPU */ |
|
if (nr_pagevec) |
|
(*nr_pagevec)++; |
|
} |
|
count += ret; |
|
} |
|
folio_batch_remove_exceptionals(&fbatch); |
|
folio_batch_release(&fbatch); |
|
cond_resched(); |
|
index++; |
|
} |
|
return count; |
|
} |
|
|
|
/** |
|
* invalidate_mapping_pages - Invalidate all clean, unlocked cache of one inode |
|
* @mapping: the address_space which holds the cache to invalidate |
|
* @start: the offset 'from' which to invalidate |
|
* @end: the offset 'to' which to invalidate (inclusive) |
|
* |
|
* This function removes pages that are clean, unmapped and unlocked, |
|
* as well as shadow entries. It will not block on IO activity. |
|
* |
|
* If you want to remove all the pages of one inode, regardless of |
|
* their use and writeback state, use truncate_inode_pages(). |
|
* |
|
* Return: the number of the cache entries that were invalidated |
|
*/ |
|
unsigned long invalidate_mapping_pages(struct address_space *mapping, |
|
pgoff_t start, pgoff_t end) |
|
{ |
|
return invalidate_mapping_pagevec(mapping, start, end, NULL); |
|
} |
|
EXPORT_SYMBOL(invalidate_mapping_pages); |
|
|
|
/* |
|
* This is like invalidate_inode_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_page_list() has a temp ref on them, or because they're transiently |
|
* sitting in the lru_cache_add() pagevecs. |
|
*/ |
|
static int invalidate_complete_folio2(struct address_space *mapping, |
|
struct folio *folio) |
|
{ |
|
if (folio->mapping != mapping) |
|
return 0; |
|
|
|
if (folio_has_private(folio) && |
|
!filemap_release_folio(folio, GFP_KERNEL)) |
|
return 0; |
|
|
|
spin_lock(&mapping->host->i_lock); |
|
xa_lock_irq(&mapping->i_pages); |
|
if (folio_test_dirty(folio)) |
|
goto failed; |
|
|
|
BUG_ON(folio_has_private(folio)); |
|
__filemap_remove_folio(folio, NULL); |
|
xa_unlock_irq(&mapping->i_pages); |
|
if (mapping_shrinkable(mapping)) |
|
inode_add_lru(mapping->host); |
|
spin_unlock(&mapping->host->i_lock); |
|
|
|
filemap_free_folio(mapping, folio); |
|
return 1; |
|
failed: |
|
xa_unlock_irq(&mapping->i_pages); |
|
spin_unlock(&mapping->host->i_lock); |
|
return 0; |
|
} |
|
|
|
static int folio_launder(struct address_space *mapping, struct folio *folio) |
|
{ |
|
if (!folio_test_dirty(folio)) |
|
return 0; |
|
if (folio->mapping != mapping || mapping->a_ops->launder_folio == NULL) |
|
return 0; |
|
return mapping->a_ops->launder_folio(folio); |
|
} |
|
|
|
/** |
|
* 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. |
|
* |
|
* Return: -EBUSY if any pages could not be invalidated. |
|
*/ |
|
int invalidate_inode_pages2_range(struct address_space *mapping, |
|
pgoff_t start, pgoff_t end) |
|
{ |
|
pgoff_t indices[PAGEVEC_SIZE]; |
|
struct folio_batch fbatch; |
|
pgoff_t index; |
|
int i; |
|
int ret = 0; |
|
int ret2 = 0; |
|
int did_range_unmap = 0; |
|
|
|
if (mapping_empty(mapping)) |
|
return 0; |
|
|
|
folio_batch_init(&fbatch); |
|
index = start; |
|
while (find_get_entries(mapping, index, end, &fbatch, indices)) { |
|
for (i = 0; i < folio_batch_count(&fbatch); i++) { |
|
struct folio *folio = fbatch.folios[i]; |
|
|
|
/* We rely upon deletion not changing folio->index */ |
|
index = indices[i]; |
|
|
|
if (xa_is_value(folio)) { |
|
if (!invalidate_exceptional_entry2(mapping, |
|
index, folio)) |
|
ret = -EBUSY; |
|
continue; |
|
} |
|
|
|
if (!did_range_unmap && folio_mapped(folio)) { |
|
/* |
|
* If folio is mapped, before taking its lock, |
|
* zap the rest of the file in one hit. |
|
*/ |
|
unmap_mapping_pages(mapping, index, |
|
(1 + end - index), false); |
|
did_range_unmap = 1; |
|
} |
|
|
|
folio_lock(folio); |
|
VM_BUG_ON_FOLIO(!folio_contains(folio, index), folio); |
|
if (folio->mapping != mapping) { |
|
folio_unlock(folio); |
|
continue; |
|
} |
|
folio_wait_writeback(folio); |
|
|
|
if (folio_mapped(folio)) |
|
unmap_mapping_folio(folio); |
|
BUG_ON(folio_mapped(folio)); |
|
|
|
ret2 = folio_launder(mapping, folio); |
|
if (ret2 == 0) { |
|
if (!invalidate_complete_folio2(mapping, folio)) |
|
ret2 = -EBUSY; |
|
} |
|
if (ret2 < 0) |
|
ret = ret2; |
|
folio_unlock(folio); |
|
} |
|
folio_batch_remove_exceptionals(&fbatch); |
|
folio_batch_release(&fbatch); |
|
cond_resched(); |
|
index++; |
|
} |
|
/* |
|
* For DAX we invalidate page tables after invalidating page cache. We |
|
* could invalidate page tables while invalidating each entry however |
|
* that would be expensive. And doing range unmapping before doesn't |
|
* work as we have no cheap way to find whether page cache entry didn't |
|
* get remapped later. |
|
*/ |
|
if (dax_mapping(mapping)) { |
|
unmap_mapping_pages(mapping, start, end - start + 1, false); |
|
} |
|
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. |
|
* |
|
* Return: -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 |
|
* @newsize: new file size |
|
* |
|
* 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 newsize) |
|
{ |
|
struct address_space *mapping = inode->i_mapping; |
|
loff_t holebegin = round_up(newsize, PAGE_SIZE); |
|
|
|
/* |
|
* 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, holebegin, 0, 1); |
|
truncate_inode_pages(mapping, newsize); |
|
unmap_mapping_range(mapping, holebegin, 0, 1); |
|
} |
|
EXPORT_SYMBOL(truncate_pagecache); |
|
|
|
/** |
|
* truncate_setsize - update inode and pagecache for a new file size |
|
* @inode: inode |
|
* @newsize: new file size |
|
* |
|
* truncate_setsize updates i_size and performs pagecache truncation (if |
|
* necessary) to @newsize. It will be typically be called from the filesystem's |
|
* setattr function when ATTR_SIZE is passed in. |
|
* |
|
* Must be called with a lock serializing truncates and writes (generally |
|
* i_rwsem but e.g. xfs uses a different lock) and before all filesystem |
|
* specific block truncation has been performed. |
|
*/ |
|
void truncate_setsize(struct inode *inode, loff_t newsize) |
|
{ |
|
loff_t oldsize = inode->i_size; |
|
|
|
i_size_write(inode, newsize); |
|
if (newsize > oldsize) |
|
pagecache_isize_extended(inode, oldsize, newsize); |
|
truncate_pagecache(inode, newsize); |
|
} |
|
EXPORT_SYMBOL(truncate_setsize); |
|
|
|
/** |
|
* pagecache_isize_extended - update pagecache after extension of i_size |
|
* @inode: inode for which i_size was extended |
|
* @from: original inode size |
|
* @to: new inode size |
|
* |
|
* Handle extension of inode size either caused by extending truncate or by |
|
* write starting after current i_size. We mark the page straddling current |
|
* i_size RO so that page_mkwrite() is called on the nearest write access to |
|
* the page. This way filesystem can be sure that page_mkwrite() is called on |
|
* the page before user writes to the page via mmap after the i_size has been |
|
* changed. |
|
* |
|
* The function must be called after i_size is updated so that page fault |
|
* coming after we unlock the page will already see the new i_size. |
|
* The function must be called while we still hold i_rwsem - this not only |
|
* makes sure i_size is stable but also that userspace cannot observe new |
|
* i_size value before we are prepared to store mmap writes at new inode size. |
|
*/ |
|
void pagecache_isize_extended(struct inode *inode, loff_t from, loff_t to) |
|
{ |
|
int bsize = i_blocksize(inode); |
|
loff_t rounded_from; |
|
struct page *page; |
|
pgoff_t index; |
|
|
|
WARN_ON(to > inode->i_size); |
|
|
|
if (from >= to || bsize == PAGE_SIZE) |
|
return; |
|
/* Page straddling @from will not have any hole block created? */ |
|
rounded_from = round_up(from, bsize); |
|
if (to <= rounded_from || !(rounded_from & (PAGE_SIZE - 1))) |
|
return; |
|
|
|
index = from >> PAGE_SHIFT; |
|
page = find_lock_page(inode->i_mapping, index); |
|
/* Page not cached? Nothing to do */ |
|
if (!page) |
|
return; |
|
/* |
|
* See clear_page_dirty_for_io() for details why set_page_dirty() |
|
* is needed. |
|
*/ |
|
if (page_mkclean(page)) |
|
set_page_dirty(page); |
|
unlock_page(page); |
|
put_page(page); |
|
} |
|
EXPORT_SYMBOL(pagecache_isize_extended); |
|
|
|
/** |
|
* truncate_pagecache_range - unmap and remove pagecache that is hole-punched |
|
* @inode: inode |
|
* @lstart: offset of beginning of hole |
|
* @lend: offset of last byte of hole |
|
* |
|
* 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_range(struct inode *inode, loff_t lstart, loff_t lend) |
|
{ |
|
struct address_space *mapping = inode->i_mapping; |
|
loff_t unmap_start = round_up(lstart, PAGE_SIZE); |
|
loff_t unmap_end = round_down(1 + lend, PAGE_SIZE) - 1; |
|
/* |
|
* This rounding is currently just for example: unmap_mapping_range |
|
* expands its hole outwards, whereas we want it to contract the hole |
|
* inwards. However, existing callers of truncate_pagecache_range are |
|
* doing their own page rounding first. Note that unmap_mapping_range |
|
* allows holelen 0 for all, and we allow lend -1 for end of file. |
|
*/ |
|
|
|
/* |
|
* Unlike in truncate_pagecache, unmap_mapping_range is called only |
|
* once (before truncating pagecache), and without "even_cows" flag: |
|
* hole-punching should not remove private COWed pages from the hole. |
|
*/ |
|
if ((u64)unmap_end > (u64)unmap_start) |
|
unmap_mapping_range(mapping, unmap_start, |
|
1 + unmap_end - unmap_start, 0); |
|
truncate_inode_pages_range(mapping, lstart, lend); |
|
} |
|
EXPORT_SYMBOL(truncate_pagecache_range);
|
|
|