Messages in this thread | | | Date | Thu, 11 May 2023 20:03:12 +0900 | From | Dominique Martinet <> | Subject | Re: [PATCH v2 4/6] kernfs: implement readdir FMODE_NOWAIT |
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Dan Carpenter wrote on Thu, May 11, 2023 at 01:55:57PM +0300: > fd7b9f7b9776b1 Tejun Heo 2013-11-28 1850 if (!dir_emit(ctx, name, len, ino, type)) > fd7b9f7b9776b1 Tejun Heo 2013-11-28 1851 return 0; > 393c3714081a53 Minchan Kim 2021-11-18 1852 down_read(&root->kernfs_rwsem); > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > Needs to be deleted.
Uh, yes, sorry; I'm not sure how I let that slip, I guess I didn't hit any dead lock because nothing ever tried to take a write lock after getdents... Thanks!
I expect there'll be other comments (this might not make it at all), so I'll keep the v3 of this patch with this fix locally and resend after other comments.
> a551138c4b3b9f Dominique Martinet 2023-05-10 1853 if (ctx->flags & DIR_CONTEXT_F_NOWAIT) { > a551138c4b3b9f Dominique Martinet 2023-05-10 1854 if (!down_read_trylock(&root->kernfs_rwsem)) > a551138c4b3b9f Dominique Martinet 2023-05-10 1855 return 0; > > It's a bit strange the this doesn't return -EAGAIN;
That is on purpose: the getdents did work (dir_emit returned success at least once), so the caller can process whatever was filled in the buffer before calling iterate_shared() again.
If we were to return -EAGAIN here, we'd actually be throwing out the entries we just filled in, and that's not what we want.
-- Dominique Martinet | Asmadeus
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