/**
* do_invalidatepage - invalidate part or all of a page
* @page: the page which is affected
- * @offset: the index of the truncation point
+ * @offset: start of the range to invalidate
+ * @length: length of the range to invalidate
*
* do_invalidatepage() is called when all or part of the page has become
* invalidated by a truncate operation.
* point. Because the caller is about to free (and possibly reuse) those
* blocks on-disk.
*/
-void do_invalidatepage(struct page *page, unsigned long offset)
+void do_invalidatepage(struct page *page, unsigned int offset,
+ unsigned int length)
{
- void (*invalidatepage)(struct page *, unsigned long);
+ void (*invalidatepage)(struct page *, unsigned int, unsigned int);
+
invalidatepage = page->mapping->a_ops->invalidatepage;
#ifdef CONFIG_BLOCK
if (!invalidatepage)
invalidatepage = block_invalidatepage;
#endif
if (invalidatepage)
- (*invalidatepage)(page, offset);
-}
-
-static inline void truncate_partial_page(struct page *page, unsigned partial)
-{
- zero_user_segment(page, partial, PAGE_CACHE_SIZE);
- cleancache_invalidate_page(page->mapping, page);
- if (page_has_private(page))
- do_invalidatepage(page, partial);
+ (*invalidatepage)(page, offset, length);
}
/*
return -EIO;
if (page_has_private(page))
- do_invalidatepage(page, 0);
+ do_invalidatepage(page, 0, PAGE_CACHE_SIZE);
cancel_dirty_page(page, PAGE_CACHE_SIZE);
* truncate_inode_pages_range - truncate range of pages specified by start & end byte offsets
* @mapping: mapping to truncate
* @lstart: offset from which to truncate
- * @lend: offset to which to truncate
+ * @lend: offset to which to truncate (inclusive)
*
* Truncate the page cache, removing the pages that are between
- * specified offsets (and zeroing out partial page
- * (if lstart is not page aligned)).
+ * specified offsets (and zeroing out partial pages
+ * if lstart or lend + 1 is not page aligned).
*
* Truncate takes two passes - the first pass is nonblocking. It will not
* block on page locks and it will not block on writeback. The second pass
* We pass down the cache-hot hint to the page freeing code. Even if the
* mapping is large, it is probably the case that the final pages are the most
* recently touched, and freeing happens in ascending file offset order.
+ *
+ * Note that since ->invalidatepage() accepts range to invalidate
+ * truncate_inode_pages_range is able to handle cases where lend + 1 is not
+ * page aligned properly.
*/
void truncate_inode_pages_range(struct address_space *mapping,
loff_t lstart, loff_t lend)
{
- const pgoff_t start = (lstart + PAGE_CACHE_SIZE-1) >> PAGE_CACHE_SHIFT;
- const unsigned partial = lstart & (PAGE_CACHE_SIZE - 1);
- struct pagevec pvec;
- pgoff_t index;
- pgoff_t end;
- int i;
+ pgoff_t start; /* inclusive */
+ pgoff_t end; /* exclusive */
+ unsigned int partial_start; /* inclusive */
+ unsigned int partial_end; /* exclusive */
+ struct pagevec pvec;
+ pgoff_t index;
+ int i;
cleancache_invalidate_inode(mapping);
if (mapping->nrpages == 0)
return;
- BUG_ON((lend & (PAGE_CACHE_SIZE - 1)) != (PAGE_CACHE_SIZE - 1));
- end = (lend >> PAGE_CACHE_SHIFT);
+ /* Offsets within partial pages */
+ partial_start = lstart & (PAGE_CACHE_SIZE - 1);
+ partial_end = (lend + 1) & (PAGE_CACHE_SIZE - 1);
+
+ /*
+ * 'start' and 'end' always covers the range of pages to be fully
+ * truncated. Partial pages are covered with 'partial_start' at the
+ * start of the range and 'partial_end' at the end of the range.
+ * Note that 'end' is exclusive while 'lend' is inclusive.
+ */
+ start = (lstart + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
+ if (lend == -1)
+ /*
+ * lend == -1 indicates end-of-file so we have to set 'end'
+ * to the highest possible pgoff_t and since the type is
+ * unsigned we're using -1.
+ */
+ end = -1;
+ else
+ end = (lend + 1) >> PAGE_CACHE_SHIFT;
pagevec_init(&pvec, 0);
index = start;
- while (index <= end && pagevec_lookup(&pvec, mapping, index,
- min(end - index, (pgoff_t)PAGEVEC_SIZE - 1) + 1)) {
+ while (index < end && pagevec_lookup(&pvec, mapping, index,
+ min(end - index, (pgoff_t)PAGEVEC_SIZE))) {
mem_cgroup_uncharge_start();
for (i = 0; i < pagevec_count(&pvec); i++) {
struct page *page = pvec.pages[i];
/* We rely upon deletion not changing page->index */
index = page->index;
- if (index > end)
+ if (index >= end)
break;
if (!trylock_page(page))
index++;
}
- if (partial) {
+ if (partial_start) {
struct page *page = find_lock_page(mapping, start - 1);
if (page) {
+ unsigned int top = PAGE_CACHE_SIZE;
+ if (start > end) {
+ /* Truncation within a single page */
+ top = partial_end;
+ partial_end = 0;
+ }
wait_on_page_writeback(page);
- truncate_partial_page(page, partial);
+ zero_user_segment(page, partial_start, top);
+ cleancache_invalidate_page(mapping, page);
+ if (page_has_private(page))
+ do_invalidatepage(page, partial_start,
+ top - partial_start);
unlock_page(page);
page_cache_release(page);
}
}
+ if (partial_end) {
+ struct page *page = find_lock_page(mapping, end);
+ if (page) {
+ wait_on_page_writeback(page);
+ zero_user_segment(page, 0, partial_end);
+ cleancache_invalidate_page(mapping, page);
+ if (page_has_private(page))
+ do_invalidatepage(page, 0,
+ partial_end);
+ unlock_page(page);
+ page_cache_release(page);
+ }
+ }
+ /*
+ * If the truncation happened within a single page no pages
+ * will be released, just zeroed, so we can bail out now.
+ */
+ if (start >= end)
+ return;
index = start;
for ( ; ; ) {
cond_resched();
if (!pagevec_lookup(&pvec, mapping, index,
- min(end - index, (pgoff_t)PAGEVEC_SIZE - 1) + 1)) {
+ min(end - index, (pgoff_t)PAGEVEC_SIZE))) {
if (index == start)
break;
index = start;
continue;
}
- if (index == start && pvec.pages[0]->index > end) {
+ if (index == start && pvec.pages[0]->index >= end) {
pagevec_release(&pvec);
break;
}
/* We rely upon deletion not changing page->index */
index = page->index;
- if (index > end)
+ if (index >= end)
break;
lock_page(page);
* 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; and truncate_inode_pages_range
- * currently BUGs if lend is not pagealigned-1 (it handles partial
- * page at start of hole, but not partial page at end of hole). Note
- * unmap_mapping_range allows holelen 0 for all, and we allow lend -1.
+ * 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.
*/
/*
projects / ~andy / linux / blobdiff