Messages in this thread | | | Date | Fri, 8 Dec 2000 14:42:51 -0800 (PST) | From | Linus Torvalds <> | Subject | Re: [PATCH] Re: kernel BUG at buffer.c:827 in test12-pre6 and 7 |
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On Fri, 8 Dec 2000, Alexander Viro wrote: > > I'm quite aware of that fact ;-) However, you said > > On the other hand, I have this suspicion that there is an even simpler > solution: stop using the end_buffer_io_sync version for writes > altogether. > > If that happens (i.e. if write requests resulting from prepare_write()/ > commit_write()/bdflush sequence become async) we must stop unlocking pages > after commit_write(). Essentially it would become unlocker of the same > kind as readpage() and writepage() - callers must assume that page submitted > to commit_write() will eventually be unlocked.
You're right, we can't do that for anonymous buffers right now. Mea culpa.
Looking more at this issue, I suspect that the easiest pretty solution that everybody can probably agree is reasonable is to either pass down the end-of-io callback to ll_rw_block as you suggested, or, preferably by just forcing the _caller_ to do the buffer locking, and just do the b_end_io stuff inside the buffer lock and get rid of all the races that way instead (and make ll_rw_block() verify that the buffers it is passed are always locked).
Linus
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