Messages in this thread | | | Date | Mon, 10 Oct 2005 18:07:05 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH] Use of getblk differs between locations |
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Mikulas Patocka <mikulas@artax.karlin.mff.cuni.cz> wrote: > > On Mon, 10 Oct 2005, Andrew Morton wrote: > > > Anton Altaparmakov <aia21@cam.ac.uk> wrote: > >> > >> > Maybe the best solution is neither one nor another. Testing and failing > >> > gracefully seems better. > >> > > >> > What do you think? > >> > >> I certainly agree with you there. I neither want a deadlock nor > >> corruption. (-: > > > > Yup. In the present implementation __getblk_slow() "cannot fail". It's > > conceivable that at some future stage we'll change __getblk_slow() so that > > it returns NULL on an out-of-memory condition. > > The question is if it is desired --- it will make bread return NULL on > out-of-memory condition, callers will treat it like an IO error, skipping > access to the affected block, causing damage on perfectly healthy > filesystem.
Yes, that is a bit dumb. A filesystem might indeed want to take different action for ENOMEM versus EIO.
> I liked what linux-2.0 did in this case --- if the kernel was out of > memory, getblk just took another buffer, wrote it if it was dirty and used > it. Except for writeable loopback device (where writing one buffer > generates more dirty buffers), it couldn't deadlock.
Wouldn't it be better if bread() were to return ERR_PTR(-EIO) or ERR_PTR(-ENOMEM)? Big change. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.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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