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Date: Wed, 26 Sep 2007 19:50:10 +0200 From: Miklos Szeredi <miklos@...redi.hu> To: haveblue@...ibm.com CC: miklos@...redi.hu, akpm@...ux-foundation.org, linux-kernel@...r.kernel.org, hch@...radead.org Subject: Re: missing mnt_drop_write() on open error > On Wed, 2007-09-26 at 10:38 +0200, Miklos Szeredi wrote: > > In __dentry_open() there's still a few places where fput() won't be > > called, notably when ->open fails, which is what I'm triggering I > > think. > > > > Also even more horrible things can happen because of the > > nd->intent.open.file thing. For example if the lookup routine calls > > lookup_instantiate_filp(), and after this, but before may_open() some > > error happens, then release_open_intent() will call fput() on the > > file, which will cause mnt_drop_write() to be called, even though a > > matching mnt_want_write() hasn't yet been called. Ugly, eh? > > I'm not sure it is _that_ horrible. ;) > > Do you see any reason we can't just shadow the > get/put_write_access(inode) calls with mnt_want/drop_write() calls? I > think they're always matched. Maybe. Can we do the mnt_want_write() from __dentry_open(), instead of may_open()? That would be a lot cleaner. Btw, may_open() doesn't do mnt_want_write() around the truncation if file is opened with O_TRUNC | O_RDONLY. Miklos - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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