fs: add a set_acl inode operation

This will allow moving all the Posix ACL handling into the VFS and clean
up tons of cruft in the filesystems.

Signed-off-by: Christoph Hellwig <[e-mail]>
Reviewed-by: Jan Kara <[e-mail]>
Signed-off-by: Al Viro <[e-mail]>

include/linux/fs.h

···
 			   struct file *, unsigned open_flag,
 			   umode_t create_mode, int *opened);
 	int (*tmpfile) (struct inode *, struct dentry *, umode_t);
+	int (*set_acl)(struct inode *, struct posix_acl *, int);
 } ____cacheline_aligned;
 
 ssize_t rw_copy_check_uvector(int type, const struct iovec __user * uvector,