fs: make sure to invalidate pages if we fall back on buffered reads
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From: Christoph Hellwig on 14 Jun 2010 04:20 On Tue, Jun 08, 2010 at 10:24:04AM -0400, Josef Bacik wrote: > Since BTRFS can fallback on buffered reads after having done some direct reads, > we need to make sure to invalidate any pages that we may have read by doing > buffered IO. This shouldn't have shown up as a visible user problem, it's just > for correctness sake. Thanks, Everything else in direct I/O land uses invalidate_inode_pages2(_range), why not this one? > loff_t *ppos = &iocb->ki_pos; > + bool invalidate = false; > > count = 0; > retval = generic_segment_checks(iov, &nr_segs, &count, VERIFY_WRITE); > @@ -1291,7 +1292,8 @@ generic_file_aio_read(struct kiocb *iocb, const struct iovec *iov, > iov, pos, nr_segs); > } > if (retval > 0) { > - *ppos = pos + retval; > + pos += retval; > + *ppos = pos; > count -= retval; > } > > @@ -1307,6 +1309,7 @@ generic_file_aio_read(struct kiocb *iocb, const struct iovec *iov, > file_accessed(filp); > goto out; > } > + invalidate = true; > } > } > > @@ -1343,6 +1346,10 @@ generic_file_aio_read(struct kiocb *iocb, const struct iovec *iov, > if (desc.count > 0) > break; > } > + if (invalidate && retval > 0) > + invalidate_mapping_pages(filp->f_mapping, > + pos >> PAGE_CACHE_SHIFT, > + (*ppos - 1) >> PAGE_CACHE_SHIFT); A little comment here would be surely useful. Telling that we want to get rid of the pages again if we were falling through from an attempted direct I/O read. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |