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authorJan Kara <jack@suse.cz>2012-09-05 15:48:23 +0200
committerJan Kara <jack@suse.cz>2012-09-05 16:06:03 +0200
commit9c2fc0de1a6e638fe58c354a463f544f42a90a09 (patch)
tree4b219b5d83336c2291c928a405d79c7ce0abdfee
parent156bddd8e505b295540f3ca0e27dda68cb0d49aa (diff)
udf: Fix data corruption for files in ICB
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. CC: <stable@vger.kernel.org> # >= 2.6.24 Reported-by: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Jan Kara <jack@suse.cz>
-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 7f3f7ba3df6e..d1c6093fd3d3 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,