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authorMiklos Szeredi <mszeredi@redhat.com>2016-08-18 09:10:44 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2016-11-26 09:56:54 +0100
commitca720a2b11b4c90d1798b406d3c191cd5395b5e3 (patch)
treeac97585291ba9748716671a967ad43c7bebe1228
parentde58c50e84e27ede34b509ad900414e43da5721a (diff)
fuse: fix fuse_write_end() if zero bytes were copied
commit 59c3b76cc61d1d676f965c192cc7969aa5cb2744 upstream. If pos is at the beginning of a page and copied is zero then page is not zeroed but is marked uptodate. Fix by skipping everything except unlock/put of page if zero bytes were copied. Reported-by: Al Viro <viro@zeniv.linux.org.uk> Fixes: 6b12c1b37e55 ("fuse: Implement write_begin/write_end callbacks") Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--fs/fuse/file.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index 3988b43c2f5a..a621dd98a865 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -1985,6 +1985,10 @@ static int fuse_write_end(struct file *file, struct address_space *mapping,
{
struct inode *inode = page->mapping->host;
+ /* Haven't copied anything? Skip zeroing, size extending, dirtying. */
+ if (!copied)
+ goto unlock;
+
if (!PageUptodate(page)) {
/* Zero any unwritten bytes at the end of the page */
size_t endoff = (pos + copied) & ~PAGE_MASK;
@@ -1995,6 +1999,8 @@ static int fuse_write_end(struct file *file, struct address_space *mapping,
fuse_write_update_size(inode, pos + copied);
set_page_dirty(page);
+
+unlock:
unlock_page(page);
put_page(page);