On Sun 13-09-26 16:49:07, Mateusz Guzik wrote:
> Currently the handling is highly error-prone with consumers allowed to
> arbitrarily manipulate references, notably with path_get().
>
> In the past this resulted in preventable bugs.
>
> The end goal, not yet achieved with this patchset, will provide an
> invariant that a populated 'struct path' has precisely one set of
> references on it.
>
> While consumers can still cause leaks by neglecting to path_put(), the
> footgun of path_get() can be eliminated.
>
> With this patchset instead of hand-rolling a path copy and issuing
> path_get() on it, callers can resort to path_clone() instead.
>
> Almost all path_get() consumers get converted, most of which with
> coccinelle.
>
> Few instances are left until I figure out a nice way to sort them out.
>
> Overall almost entirety of this patchset is a NOP.
I like most of the changes. Just the changes to path_init() kind of leave a
bad taste because they leave struct path assignment there for the RCU
lookup mode. But I don't see a nicer way of dealing with it.
Honza
>
> Mateusz Guzik (10):
> fs: unexport backing_file_set_user_path() and make it take the ref on
> its own
> fs: add path_create(), path_move() and path_clone()
> fs: use path_clone() in path_init()
> fs: use path_clone() and path_move() in vfs_open*
> fs: use path_clone() in backing_file_set_user_path()
> Coccinelle-based conversion of path_* consumers to use the new
> primitives
> autofs: use path_create()
> fsnotify: use path_clone()
> proc: use path_clone()
> nfsd: use path_clone()
>
> drivers/block/loop.c | 3 +-
> fs/autofs/dev-ioctl.c | 3 +-
> fs/autofs/expire.c | 4 +--
> fs/backing-file.c | 2 --
> fs/devpts/inode.c | 6 ++--
> fs/failfs.c | 3 +-
> fs/fhandle.c | 3 +-
> fs/file_attr.c | 6 ++--
> fs/file_table.c | 3 +-
> fs/fs_struct.c | 6 ++--
> fs/namei.c | 44 ++++++++++++++++++++++++------
> fs/namespace.c | 3 +-
> fs/nfsd/export.c | 6 ++--
> fs/nfsd/nfs4xdr.c | 8 +++---
> fs/notify/fanotify/fanotify.c | 6 ++--
> fs/notify/fanotify/fanotify_user.c | 3 +-
> fs/nsfs.c | 3 +-
> fs/open.c | 10 ++-----
> fs/overlayfs/params.c | 3 +-
> fs/pidfs.c | 3 +-
> fs/proc/base.c | 6 ++--
> fs/proc/fd.c | 3 +-
> fs/smb/server/vfs.c | 3 +-
> fs/xfs/xfs_handle.c | 3 +-
> include/linux/path.h | 14 ++++++++--
> kernel/trace/bpf_trace.c | 3 +-
> security/apparmor/task.c | 3 +-
> security/keys/big_key.c | 3 +-
> security/landlock/fs.c | 3 +-
> security/landlock/syscalls.c | 3 +-
> 30 files changed, 87 insertions(+), 85 deletions(-)
>
> --
> 2.53.0
>
--
Jan Kara <jack@suse.com>
SUSE Labs, CR