fs: expose LOOKUP_CACHED through openat2() RESOLVE_CACHED

Now that we support non-blocking path resolution internally, expose it
via openat2() in the struct open_how ->resolve flags. This allows
applications using openat2() to limit path resolution to the extent that
it is already cached.

If the lookup cannot be satisfied in a non-blocking manner, openat2(2)
will return -1/-EAGAIN.

Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Jens Axboe 2020-12-17 09:19:10 -07:00 committed by Al Viro
parent 6c6ec2b0a3
commit 99668f6180
3 changed files with 11 additions and 1 deletions

View file

@ -35,5 +35,9 @@ struct open_how {
#define RESOLVE_IN_ROOT 0x10 /* Make all jumps to "/" and ".."
be scoped inside the dirfd
(similar to chroot(2)). */
#define RESOLVE_CACHED 0x20 /* Only complete if resolution can be
completed through cached lookup. May
return -EAGAIN if that's not
possible. */
#endif /* _UAPI_LINUX_OPENAT2_H */