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authorJan Kara <jack@suse.cz>2012-09-05 15:48:23 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-09-14 10:00:50 -0700
commit31147bc619c3379e335726e071ea012784ad9877 (patch)
tree537e852125f967e865f5f9277acb469c96bc79d0 /fs/udf
parent778105ad42f80ed3408ede5c2f98078bc22db06d (diff)
udf: Fix data corruption for files in ICB
commit 9c2fc0de1a6e638fe58c354a463f544f42a90a09 upstream. When a file is stored in ICB (inode), we overwrite part of the file, and the page containing file's data is not in page cache, we end up corrupting file's data by overwriting them with zeros. The problem is we use simple_write_begin() which simply zeroes parts of the page which are not written to. The problem has been introduced by be021ee4 (udf: convert to new aops). Fix the problem by providing a ->write_begin function which makes the page properly uptodate. Reported-by: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs/udf')
-rw-r--r--fs/udf/file.c35
1 files changed, 29 insertions, 6 deletions
diff --git a/fs/udf/file.c b/fs/udf/file.c
index 3438b0000413..8eb9628e6824 100644
--- a/fs/udf/file.c
+++ b/fs/udf/file.c
@@ -39,20 +39,24 @@
#include "udf_i.h"
#include "udf_sb.h"
-static int udf_adinicb_readpage(struct file *file, struct page *page)
+static void __udf_adinicb_readpage(struct page *page)
{
struct inode *inode = page->mapping->host;
char *kaddr;
struct udf_inode_info *iinfo = UDF_I(inode);
- BUG_ON(!PageLocked(page));
-
kaddr = kmap(page);
- memset(kaddr, 0, PAGE_CACHE_SIZE);
memcpy(kaddr, iinfo->i_ext.i_data + iinfo->i_lenEAttr, inode->i_size);
+ memset(kaddr + inode->i_size, 0, PAGE_CACHE_SIZE - inode->i_size);
flush_dcache_page(page);
SetPageUptodate(page);
kunmap(page);
+}
+
+static int udf_adinicb_readpage(struct file *file, struct page *page)
+{
+ BUG_ON(!PageLocked(page));
+ __udf_adinicb_readpage(page);
unlock_page(page);
return 0;
@@ -77,6 +81,25 @@ static int udf_adinicb_writepage(struct page *page,
return 0;
}
+static int udf_adinicb_write_begin(struct file *file,
+ struct address_space *mapping, loff_t pos,
+ unsigned len, unsigned flags, struct page **pagep,
+ void **fsdata)
+{
+ struct page *page;
+
+ if (WARN_ON_ONCE(pos >= PAGE_CACHE_SIZE))
+ return -EIO;
+ page = grab_cache_page_write_begin(mapping, 0, flags);
+ if (!page)
+ return -ENOMEM;
+ *pagep = page;
+
+ if (!PageUptodate(page) && len != PAGE_CACHE_SIZE)
+ __udf_adinicb_readpage(page);
+ return 0;
+}
+
static int udf_adinicb_write_end(struct file *file,
struct address_space *mapping,
loff_t pos, unsigned len, unsigned copied,
@@ -98,8 +121,8 @@ static int udf_adinicb_write_end(struct file *file,
const struct address_space_operations udf_adinicb_aops = {
.readpage = udf_adinicb_readpage,
.writepage = udf_adinicb_writepage,
- .write_begin = simple_write_begin,
- .write_end = udf_adinicb_write_end,
+ .write_begin = udf_adinicb_write_begin,
+ .write_end = udf_adinicb_write_end,
};
static ssize_t udf_file_aio_write(struct kiocb *iocb, const struct iovec *iov,