diff options
| -rw-r--r-- | include/linux/mm.h | 2 | ||||
| -rw-r--r-- | mm/truncate.c | 44 |
2 files changed, 39 insertions, 7 deletions
diff --git a/include/linux/mm.h b/include/linux/mm.h index a06a84d..92acae9 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -896,6 +896,8 @@ extern unsigned long do_brk(unsigned long, unsigned long); /* filemap.c */ extern unsigned long page_unuse(struct page *); extern void truncate_inode_pages(struct address_space *, loff_t); +extern void truncate_inode_pages_range(struct address_space *, + loff_t lstart, loff_t lend); /* generic vm_area_ops exported for stackable file systems */ extern struct page *filemap_nopage(struct vm_area_struct *, unsigned long, int *); diff --git a/mm/truncate.c b/mm/truncate.c index 9173ab50..7dee327 100644 --- a/mm/truncate.c +++ b/mm/truncate.c @@ -82,12 +82,15 @@ invalidate_complete_page(struct address_space *mapping, struct page *page) } /** - * truncate_inode_pages - truncate *all* the pages from an offset + * truncate_inode_pages - truncate range of pages specified by start and + * end byte offsets * @mapping: mapping to truncate * @lstart: offset from which to truncate + * @lend: offset to which to truncate * - * Truncate the page cache at a set offset, removing the pages that are beyond - * that offset (and zeroing out partial pages). + * Truncate the page cache, removing the pages that are between + * specified offsets (and zeroing out partial page + * (if lstart 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 @@ -101,12 +104,12 @@ invalidate_complete_page(struct address_space *mapping, struct page *page) * 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. - * - * Called under (and serialised by) inode->i_sem. */ -void truncate_inode_pages(struct address_space *mapping, loff_t lstart) +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; + pgoff_t end; const unsigned partial = lstart & (PAGE_CACHE_SIZE - 1); struct pagevec pvec; pgoff_t next; @@ -115,13 +118,22 @@ void truncate_inode_pages(struct address_space *mapping, loff_t lstart) if (mapping->nrpages == 0) return; + BUG_ON((lend & (PAGE_CACHE_SIZE - 1)) != (PAGE_CACHE_SIZE - 1)); + end = (lend >> PAGE_CACHE_SHIFT); + pagevec_init(&pvec, 0); next = start; - while (pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) { + while (next <= end && + pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) { for (i = 0; i < pagevec_count(&pvec); i++) { struct page *page = pvec.pages[i]; pgoff_t page_index = page->index; + if (page_index > end) { + next = page_index; + break; + } + if (page_index > next) next = page_index; next++; @@ -157,9 +169,15 @@ void truncate_inode_pages(struct address_space *mapping, loff_t lstart) next = start; continue; } + if (pvec.pages[0]->index > end) { + pagevec_release(&pvec); + break; + } for (i = 0; i < pagevec_count(&pvec); i++) { struct page *page = pvec.pages[i]; + if (page->index > end) + break; lock_page(page); wait_on_page_writeback(page); if (page->index > next) @@ -171,7 +189,19 @@ void truncate_inode_pages(struct address_space *mapping, loff_t lstart) pagevec_release(&pvec); } } +EXPORT_SYMBOL(truncate_inode_pages_range); +/** + * truncate_inode_pages - truncate *all* the pages from an offset + * @mapping: mapping to truncate + * @lstart: offset from which to truncate + * + * Called under (and serialised by) inode->i_sem. + */ +void truncate_inode_pages(struct address_space *mapping, loff_t lstart) +{ + truncate_inode_pages_range(mapping, lstart, (loff_t)-1); +} EXPORT_SYMBOL(truncate_inode_pages); /** |
