truncate: new helpers

Introduce new truncate helpers truncate_pagecache and inode_newsize_ok.
vmtruncate is also consolidated from mm/memory.c and mm/nommu.c and
into mm/truncate.c.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

2 files changed, 5 insertions, 3 deletions

diff --git a/include/linux/fs.h b/include/linux/fs.h
index 502d96ef345..2b08b5ce09b 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2382,7 +2382,8 @@ extern int buffer_migrate_page(struct address_space *,
 #define buffer_migrate_page NULL
 #endif
 
-extern int inode_change_ok(struct inode *, struct iattr *);
+extern int inode_change_ok(const struct inode *, struct iattr *);
+extern int inode_newsize_ok(const struct inode *, loff_t offset);
 extern int __must_check inode_setattr(struct inode *, struct iattr *);
 
 extern void file_update_time(struct file *file);
diff --git a/include/linux/mm.h b/include/linux/mm.h
index b6eae5e3144..8347e938fb2 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -791,8 +791,9 @@ static inline void unmap_shared_mapping_range(struct address_space *mapping,
         unmap_mapping_range(mapping, holebegin, holelen, 0);
 }
 
-extern int vmtruncate(struct inode * inode, loff_t offset);
-extern int vmtruncate_range(struct inode * inode, loff_t offset, loff_t end);
+extern void truncate_pagecache(struct inode *inode, loff_t old, loff_t new);
+extern int vmtruncate(struct inode *inode, loff_t offset);
+extern int vmtruncate_range(struct inode *inode, loff_t offset, loff_t end);
 
 #ifdef CONFIG_MMU
 extern int handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma,