[PATCH v2] hfsplus: fix expand when not enough available space

[Sergei Antonov <saproj@gmail.com>]

v1->v2
* Description clarified.

Fix a bug which is reproduced as follows. Create a file:
 echo abc > test_file
Try to expand the file beyond available space:
 truncate --size=<size exceeding available space> test_file
Since HFS+ does not support file size > allocated size, truncate should fail.
However, it ends successfully. The driver returns success despite having been
unable to allocate the requested space for the file. Also filesystem check finds
an error:
 Checking catalog file.
 Incorrect size for file test_file
 (It should be 469094400 instead of 1000000000)

Add a piece of code analogous to code in the fat driver.
Now a proper error is returned and filesystem remains consistent.

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Vyacheslav Dubeyko <slava@dubeyko.com>
Cc: Hin-Tak Leung <htl10@users.sourceforge.net>
Cc: Anton Altaparmakov <aia21@cam.ac.uk>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Sougata Santra <sougata@tuxera.com>
Signed-off-by: Sergei Antonov <saproj@gmail.com>
---
 fs/hfsplus/inode.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/fs/hfsplus/inode.c b/fs/hfsplus/inode.c
index 0cf786f..7691cc1 100644
--- a/fs/hfsplus/inode.c
+++ b/fs/hfsplus/inode.c
@@ -254,6 +254,12 @@ static int hfsplus_setattr(struct dentry *dentry, struct iattr *attr)
 	if ((attr->ia_valid & ATTR_SIZE) &&
 	    attr->ia_size != i_size_read(inode)) {
 		inode_dio_wait(inode);
+		if (attr->ia_size > inode->i_size) {
+			error = generic_cont_expand_simple(inode,
+							   attr->ia_size);
+			if (error)
+				return error;
+		}
 		truncate_setsize(inode, attr->ia_size);
 		hfsplus_file_truncate(inode);
 	}
-- 
2.1.2