[Devel] [PATCH rh7 3/3] ext4: fix mmap data corruption when blocksize < pagesize

[Cyrill Gorcunov]

From: Jan Kara <jack at suse.cz>

Use truncate_isize_extended() when hole is being created in a file so that
->page_mkwrite() will get called for the partial tail page if it is
mmaped (see the first patch in the series for details).

gorcunov@:
 - ML d6320cbfc92910a3e5f10c42d98c231c98db4f60
 - https://jira.sw.ru/browse/PSBM-34383

Signed-off-by: Jan Kara <jack at suse.cz>
Signed-off-by: Theodore Ts'o <tytso at mit.edu>
Signed-off-by: Cyrill Gorcunov <gorcunov at virtuozzo.com>
---
 fs/ext4/inode.c |    6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

Index: linux-pcs7.git/fs/ext4/inode.c
===================================================================
--- linux-pcs7.git.orig/fs/ext4/inode.c
+++ linux-pcs7.git/fs/ext4/inode.c
@@ -4849,8 +4849,12 @@ int ext4_setattr(struct dentry *dentry,
 				ext4_orphan_del(NULL, inode);
 				goto err_out;
 			}
-		} else
+		} else {
+			loff_t oldsize = inode->i_size;
+
 			i_size_write(inode, attr->ia_size);
+			pagecache_isize_extended(inode, oldsize, inode->i_size);
+		}
 
 		/*
 		 * Blocks are going to be removed from the inode. Wait