From 8a549bea51138be2126a2cc6aabe8f17ef66b79b Mon Sep 17 00:00:00 2001 From: Hugh Dickins Date: Mon, 25 Jul 2011 17:12:24 -0700 Subject: mm: tidy vmtruncate_range and related functions Use consistent variable names in truncate_pagecache(), truncate_setsize(), vmtruncate() and vmtruncate_range(). unmap_mapping_range() and vmtruncate_range() have mismatched interfaces: don't change either, but make the vmtruncates more precise about what they expect unmap_mapping_range() to do. vmtruncate_range() is currently called only with page-aligned start and end+1: can handle unaligned start, but unaligned end+1 would hit BUG_ON in truncate_inode_pages_range() (lacks partial clearing of the end page). Signed-off-by: Hugh Dickins Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/truncate.c | 31 +++++++++++++++++-------------- 1 file changed, 17 insertions(+), 14 deletions(-) (limited to 'mm/truncate.c') diff --git a/mm/truncate.c b/mm/truncate.c index 003c6c685fc8..c924764e2ce5 100644 --- a/mm/truncate.c +++ b/mm/truncate.c @@ -531,8 +531,8 @@ EXPORT_SYMBOL_GPL(invalidate_inode_pages2); /** * truncate_pagecache - unmap and remove pagecache that has been truncated * @inode: inode - * @old: old file offset - * @new: new file offset + * @oldsize: old file size + * @newsize: new file size * * inode's new i_size must already be written before truncate_pagecache * is called. @@ -544,9 +544,10 @@ EXPORT_SYMBOL_GPL(invalidate_inode_pages2); * 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 old, loff_t new) +void truncate_pagecache(struct inode *inode, loff_t oldsize, 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 @@ -557,9 +558,9 @@ void truncate_pagecache(struct inode *inode, loff_t old, loff_t new) * truncate_inode_pages finishes, hence the second * unmap_mapping_range call must be made for correctness. */ - unmap_mapping_range(mapping, new + PAGE_SIZE - 1, 0, 1); - truncate_inode_pages(mapping, new); - unmap_mapping_range(mapping, new + PAGE_SIZE - 1, 0, 1); + unmap_mapping_range(mapping, holebegin, 0, 1); + truncate_inode_pages(mapping, newsize); + unmap_mapping_range(mapping, holebegin, 0, 1); } EXPORT_SYMBOL(truncate_pagecache); @@ -589,29 +590,31 @@ EXPORT_SYMBOL(truncate_setsize); /** * vmtruncate - unmap mappings "freed" by truncate() syscall * @inode: inode of the file used - * @offset: file offset to start truncating + * @newsize: file offset to start truncating * * This function is deprecated and truncate_setsize or truncate_pagecache * should be used instead, together with filesystem specific block truncation. */ -int vmtruncate(struct inode *inode, loff_t offset) +int vmtruncate(struct inode *inode, loff_t newsize) { int error; - error = inode_newsize_ok(inode, offset); + error = inode_newsize_ok(inode, newsize); if (error) return error; - truncate_setsize(inode, offset); + truncate_setsize(inode, newsize); if (inode->i_op->truncate) inode->i_op->truncate(inode); return 0; } EXPORT_SYMBOL(vmtruncate); -int vmtruncate_range(struct inode *inode, loff_t offset, loff_t end) +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 @@ -623,10 +626,10 @@ int vmtruncate_range(struct inode *inode, loff_t offset, loff_t end) mutex_lock(&inode->i_mutex); inode_dio_wait(inode); - unmap_mapping_range(mapping, offset, (end - offset), 1); - inode->i_op->truncate_range(inode, offset, end); + 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, offset, (end - offset), 1); + unmap_mapping_range(mapping, holebegin, holelen, 1); mutex_unlock(&inode->i_mutex); return 0; -- cgit v1.2.3