#include <linux/buffer_head.h> /* grr. try_to_release_page,
do_invalidatepage */
#include <linux/cleancache.h>
+#include <linux/rmap.h>
#include "internal.h"
if (page_has_private(page) && !try_to_release_page(page, GFP_KERNEL))
return 0;
+ clear_page_mlock(page);
+
spin_lock_irq(&mapping->tree_lock);
if (PageDirty(page))
goto failed;
- clear_page_mlock(page);
BUG_ON(page_has_private(page));
__delete_from_page_cache(page);
spin_unlock_irq(&mapping->tree_lock);
oldsize = inode->i_size;
i_size_write(inode, newsize);
-
+ if (newsize > oldsize)
+ pagecache_isize_extended(inode, oldsize, newsize);
truncate_pagecache(inode, oldsize, 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_mutex - 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 = 1 << inode->i_blkbits;
+ loff_t rounded_from;
+ struct page *page;
+ pgoff_t index;
+
+ WARN_ON(to > inode->i_size);
+
+ if (from >= to || bsize == PAGE_CACHE_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_CACHE_SIZE - 1)))
+ return;
+
+ index = from >> PAGE_CACHE_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);
+ page_cache_release(page);
+}
+EXPORT_SYMBOL(pagecache_isize_extended);
+
/**
* vmtruncate - unmap mappings "freed" by truncate() syscall
* @inode: inode of the file used
return 0;
}
EXPORT_SYMBOL(vmtruncate);
-
-int vmtruncate_range(struct inode *inode, loff_t lstart, loff_t lend)
-{
- struct address_space *mapping = inode->i_mapping;
- loff_t holebegin = round_up(lstart, PAGE_SIZE);
- loff_t holelen = 1 + lend - holebegin;
-
- /*
- * If the underlying filesystem is not going to provide
- * a way to truncate a range of blocks (punch a hole) -
- * we should return failure right now.
- */
- if (!inode->i_op->truncate_range)
- return -ENOSYS;
-
- mutex_lock(&inode->i_mutex);
- inode_dio_wait(inode);
- unmap_mapping_range(mapping, holebegin, holelen, 1);
- inode->i_op->truncate_range(inode, lstart, lend);
- /* unmap again to remove racily COWed private pages */
- unmap_mapping_range(mapping, holebegin, holelen, 1);
- mutex_unlock(&inode->i_mutex);
-
- return 0;
-}