splice: introduce FMODE_SPLICE_READ and FMODE_SPLICE_WRITE

Introduce FMODE_SPLICE_READ and FMODE_SPLICE_WRITE. These modes check
whether it is legal to read or write a file using splice. Both get
automatically set on regular files and are not checked when a 'struct
fileoperations' includes the splice_{read,write} methods.

Change-Id: Ice6a3fab20bf0ac131f8d908f4bb0f7dc34bf4e3
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>

1 files changed, 4 insertions, 0 deletions

diff --git a/fs/open.c b/fs/open.c
index 5f129683b..1930f2362 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -680,6 +680,10 @@ static int do_dentry_open(struct file *f,
 		return 0;
 	}
 
+	if (S_ISREG(inode->i_mode))
+		f->f_mode |= FMODE_SPLICE_WRITE | FMODE_SPLICE_READ;
+
+
 	f->f_op = fops_get(inode->i_fop);
 
 	error = security_file_open(f, cred);