check ATTR_SIZE contraints in inode_change_ok

Make sure we check the truncate constraints early on in ->setattr by adding
those checks to inode_change_ok.  Also clean up and document inode_change_ok
to make this obvious.

As a fallout we don't have to call inode_newsize_ok from simple_setsize and
simplify it down to a truncate_setsize which doesn't return an error.  This
simplifies a lot of setattr implementations and means we use truncate_setsize
almost everywhere.  Get rid of fat_setsize now that it's trivial and mark
ext2_setsize static to make the calling convention obvious.

Keep the inode_newsize_ok in vmtruncate for now as all callers need an
audit for its removal anyway.

Note: setattr code in ecryptfs doesn't call inode_change_ok at all and
needs a deeper audit, but that is left for later.

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

2 files changed, 2 insertions, 16 deletions

diff --git a/fs/fat/fat.h b/fs/fat/fat.h
index 27ac257..d75a77f 100644
--- a/fs/fat/fat.h
+++ b/fs/fat/fat.h
@@ -306,7 +306,6 @@ extern long fat_generic_ioctl(struct file *filp, unsigned int cmd,
 extern const struct file_operations fat_file_operations;
 extern const struct inode_operations fat_file_inode_operations;
 extern int fat_setattr(struct dentry * dentry, struct iattr * attr);
-extern int fat_setsize(struct inode *inode, loff_t offset);
 extern void fat_truncate_blocks(struct inode *inode, loff_t offset);
 extern int fat_getattr(struct vfsmount *mnt, struct dentry *dentry,
 		       struct kstat *stat);
diff --git a/fs/fat/file.c b/fs/fat/file.c
index b2eedce..7257752 100644
--- a/fs/fat/file.c
+++ b/fs/fat/file.c
@@ -364,18 +364,6 @@ static int fat_allow_set_time(struct msdos_sb_info *sbi, struct inode *inode)
 	return 0;
 }
 
-int fat_setsize(struct inode *inode, loff_t offset)
-{
-	int error;
-
-	error = simple_setsize(inode, offset);
-	if (error)
-		return error;
-	fat_truncate_blocks(inode, offset);
-
-	return error;
-}
-
 #define TIMES_SET_FLAGS	(ATTR_MTIME_SET | ATTR_ATIME_SET | ATTR_TIMES_SET)
 /* valid file mode bits */
 #define FAT_VALID_MODE	(S_IFREG | S_IFDIR | S_IRWXUGO)
@@ -441,9 +429,8 @@ int fat_setattr(struct dentry *dentry, struct iattr *attr)
 	}
 
 	if (attr->ia_valid & ATTR_SIZE) {
-		error = fat_setsize(inode, attr->ia_size);
-		if (error)
-			goto out;
+		truncate_setsize(inode, attr->ia_size);
+		fat_truncate_blocks(inode, attr->ia_size);
 	}
 
 	setattr_copy(inode, attr);