[tytso Cc'd]
On Sat, Apr 17, 2021 at 06:09:44PM +0000, Al Viro wrote:
> > Al - fairly trivial patch applied, comments?
>
> Should be fine... FWIW, I've a patch in the same area, making those suckers
> return bool. Seeing that they are only ever called via dir_emit(),
> dir_emit_dot()
> and dir_emit_dotdot() and all of those return ->actor(...) == 0...
>
> Anyway, that'd be trivial to rebase on top of yours.
Actually... looking through that patch now I've noticed something fishy:
in 1f60fbe72749 ("ext4: allow readdir()'s of large empty directories to
be interrupted" we had
@@ -169,6 +169,8 @@ static int filldir(struct dir_context *ctx, const char
*name, int namlen,
}
dirent = buf->previous;
if (dirent) {
+ if (signal_pending(current))
+ return -EINTR;
and that thing is still there. However, it does *NOT* do what it might
appear to be doing; it ends up with getdents() returning -EINVAL instead.
What we need is
buf->error = -EINTR;
in addition to that return (in all 3 such places). Do you have any problems
with
the following delta?
diff --git a/fs/readdir.c b/fs/readdir.c
index 19434b3c982c..c742db935847 100644
--- a/fs/readdir.c
+++ b/fs/readdir.c
@@ -239,8 +239,10 @@ static int filldir(struct dir_context *ctx, const char
*name, int namlen,
return -EOVERFLOW;
}
prev_reclen = buf->prev_reclen;
- if (prev_reclen && signal_pending(current))
+ if (prev_reclen && signal_pending(current)) {
+ buf->error = -EINTR;
return -EINTR;
+ }
dirent = buf->current_dir;
prev = (void __user *) dirent - prev_reclen;
if (!user_write_access_begin(prev, reclen + prev_reclen))
@@ -321,8 +323,10 @@ static int filldir64(struct dir_context *ctx, const char
*name, int namlen,
if (reclen > buf->count)
return -EINVAL;
prev_reclen = buf->prev_reclen;
- if (prev_reclen && signal_pending(current))
+ if (prev_reclen && signal_pending(current)) {
+ buf->error = -EINTR;
return -EINTR;
+ }
dirent = buf->current_dir;
prev = (void __user *)dirent - prev_reclen;
if (!user_write_access_begin(prev, reclen + prev_reclen))
@@ -488,8 +492,10 @@ static int compat_filldir(struct dir_context *ctx, const
char *name, int namlen,
return -EOVERFLOW;
}
prev_reclen = buf->prev_reclen;
- if (prev_reclen && signal_pending(current))
+ if (prev_reclen && signal_pending(current)) {
+ buf->error = -EINTR;
return -EINTR;
+ }
dirent = buf->current_dir;
prev = (void __user *) dirent - prev_reclen;
if (!user_write_access_begin(prev, reclen + prev_reclen))
