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 <hughd@xxxxxxxxxx>
---
mm/truncate.c | 31 +++++++++++++++++--------------
1 file changed, 17 insertions(+), 14 deletions(-)
--- linux.orig/mm/truncate.c 2011-06-05 17:42:31.341466507 -0700
+++ linux/mm/truncate.c 2011-06-05 19:19:52.254430023 -0700
@@ -526,8 +526,8 @@ EXPORT_SYMBOL_GPL(invalidate_inode_pages
/**
* 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.
@@ -539,9 +539,10 @@ EXPORT_SYMBOL_GPL(invalidate_inode_pages
* 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
@@ -552,9 +553,9 @@ void truncate_pagecache(struct inode *in
* 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);
@@ -584,29 +585,31 @@ 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
@@ -618,10 +621,10 @@ int vmtruncate_range(struct inode *inode
mutex_lock(&inode->i_mutex);
down_write(&inode->i_alloc_sem);
- 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);
up_write(&inode->i_alloc_sem);
mutex_unlock(&inode->i_mutex);
--
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