On Fri, Apr 7, 2017 at 11:01 AM, Amir Goldstein <amir73il@xxxxxxxxx> wrote: > ftruncate an overlayfs inode was checking IS_APPEND() on > overlay inode, but overlay inode does not have the S_APPEND flag. > > Set 'inode' var to file_inode() so all checks are performed on > the real inode and use the overlay inode/sb explicitly for > freeze protection and file lock checks. If you'd just add the file_inode() to the IS_APPEND check then the patch would look a lot less complicated and the effect should be exactly the same. Am I missing something? Thanks, Miklos > > Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx> > --- > fs/open.c | 8 ++++---- > 1 file changed, 4 insertions(+), 4 deletions(-) > > diff --git a/fs/open.c b/fs/open.c > index 949cef2..b7d5ab1 100644 > --- a/fs/open.c > +++ b/fs/open.c > @@ -182,7 +182,7 @@ static long do_sys_ftruncate(unsigned int fd, loff_t length, int small) > small = 0; > > dentry = f.file->f_path.dentry; > - inode = dentry->d_inode; > + inode = file_inode(f.file); > error = -EINVAL; > if (!S_ISREG(inode->i_mode) || !(f.file->f_mode & FMODE_WRITE)) > goto out_putf; > @@ -196,13 +196,13 @@ static long do_sys_ftruncate(unsigned int fd, loff_t length, int small) > if (IS_APPEND(inode)) > goto out_putf; > > - sb_start_write(inode->i_sb); > - error = locks_verify_truncate(inode, f.file, length); > + sb_start_write(dentry->d_sb); > + error = locks_verify_truncate(d_inode(dentry), f.file, length); > if (!error) > error = security_path_truncate(&f.file->f_path); > if (!error) > error = do_truncate(dentry, length, ATTR_MTIME|ATTR_CTIME, f.file); > - sb_end_write(inode->i_sb); > + sb_end_write(dentry->d_sb); > out_putf: > fdput(f); > out: > -- > 2.7.4 >
