This enables to use linkat to create hardlinks from a file descriptor pointing to the file. This can be used with open_by_handle syscall that returns a file descriptor. Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx> --- fs/namei.c | 34 +++++++++++++++++++++++++--------- 1 files changed, 25 insertions(+), 9 deletions(-) diff --git a/fs/namei.c b/fs/namei.c index a6a8093..9a7b71a 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -2553,16 +2553,28 @@ SYSCALL_DEFINE5(linkat, int, olddfd, const char __user *, oldname, { struct dentry *new_dentry; struct nameidata nd; - struct path old_path; - int error; + struct path old_path, *old_pathp; + struct file *file = NULL; + int error, fput_needed; char *to; if ((flags & ~AT_SYMLINK_FOLLOW) != 0) return -EINVAL; - error = user_path_at(olddfd, oldname, - flags & AT_SYMLINK_FOLLOW ? LOOKUP_FOLLOW : 0, - &old_path); + if (oldname == NULL && olddfd != AT_FDCWD) { + file = fget_light(olddfd, &fput_needed); + if (file) { + old_pathp = &file->f_path; + error = 0; + } else + error = -EBADF; + } else { + error = user_path_at(olddfd, oldname, + flags & AT_SYMLINK_FOLLOW ? + LOOKUP_FOLLOW : 0, + &old_path); + old_pathp = &old_path; + } if (error) return error; @@ -2570,7 +2582,7 @@ SYSCALL_DEFINE5(linkat, int, olddfd, const char __user *, oldname, if (error) goto out; error = -EXDEV; - if (old_path.mnt != nd.path.mnt) + if (old_pathp->mnt != nd.path.mnt) goto out_release; new_dentry = lookup_create(&nd, 0); error = PTR_ERR(new_dentry); @@ -2579,10 +2591,11 @@ SYSCALL_DEFINE5(linkat, int, olddfd, const char __user *, oldname, error = mnt_want_write(nd.path.mnt); if (error) goto out_dput; - error = security_path_link(old_path.dentry, &nd.path, new_dentry); + error = security_path_link(old_pathp->dentry, &nd.path, new_dentry); if (error) goto out_drop_write; - error = vfs_link(old_path.dentry, nd.path.dentry->d_inode, new_dentry); + error = vfs_link(old_pathp->dentry, + nd.path.dentry->d_inode, new_dentry); out_drop_write: mnt_drop_write(nd.path.mnt); out_dput: @@ -2593,7 +2606,10 @@ out_release: path_put(&nd.path); putname(to); out: - path_put(&old_path); + if (file) + fput_light(file, fput_needed); + else + path_put(&old_path); return error; } -- 1.7.2.rc1 -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html