Messages in this thread | | | From | Neil Brown <> | Date | Tue, 12 Jun 2007 10:16:22 +1000 | Subject | Re: [PATCH 001 of 2] Fix read/truncate race. |
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On Thursday June 7, akpm@linux-foundation.org wrote: > On Fri, 8 Jun 2007 12:48:48 +1000 Neil Brown <neilb@suse.de> wrote: > > > The following patch will remove the extra seqlock except when we > > actually need it and remove the extra arithmetic - but I haven't > > tested it or reviewed it properly. I can do that if you think it is > > the right direction. > > Yes, the optimisation is valid and looks useful. > > > ./mm/filemap.c | 34 ++++++++++++++++++++++++++++------ > > It didn't apply - your tree seems different from mine.
Odd. I had no other changes to that file in my tree. I'll wait until the next -mm(?). It's just as well really, the patch was buggy - didn't even compile and (as I said) totally untested. I'll get you a tested patch after I can rebase.
> > > + * > > + * NOTE: This access of inode->i_size is not protected > > + * and if there is a concurrent update on a 32bit machine, > > + * it could return the wrong value. This could only be a problem > > + * if i_size has actually changed to a smaller value before the > > + * page became uptodate, and at this point it still has a smaller > > + * value, but due to a race while reading, it appears unchanged. > > + * The chances of this happening are so small and the consequence > > + * sufficiently minor, that the cost of the seqlock seems > > + * not to be justified. > > please consider incorporating scripts/checkpatch.pl into your patch > preparation toolchain.
Done... Any reason that it isn't executable (chmod +x)?
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