From: Christoph Hellwig <hch@lst.de>
To: Dave Chinner <david@fromorbit.com>
Cc: Christoph Hellwig <hch@lst.de>, linux-xfs@vger.kernel.org
Subject: Re: [PATCH 08/20] xfs: factor out splitting of an iclog from xlog_sync
Date: Fri, 24 May 2019 08:16:50 +0200 [thread overview]
Message-ID: <20190524061650.GB2235@lst.de> (raw)
In-Reply-To: <20190523231726.GU29573@dread.disaster.area>
On Fri, May 24, 2019 at 09:17:26AM +1000, Dave Chinner wrote:
> > +/*
> > + * Bump the cycle numbers at the start of each block in the part of the iclog
> > + * that ends up in the buffer that gets written to the start of the log.
> > + *
> > + * Watch out for the header magic number case, though.
>
> Can we update this comment to be easier to parse?
>
> /*
> * We need to bump cycle number for the part of the iclog that is
> * written to the start of the log. Watch out for the header magic
> * number case, though.
> */
Sure.
> > + for (i = split_offset; i < count; i += BBSIZE) {
> > + uint32_t cycle = get_unaligned_be32(data + i);
> > +
> > + if (++cycle == XLOG_HEADER_MAGIC_NUM)
> > + cycle++;
> > + put_unaligned_be32(cycle, data + i);
>
> Is the location we read from/write to ever unaligned? The cycle
> should always be 512 byte aligned to the start of the iclog data
> buffer, which should always be at least 4 byte aligned in memory...
I don't think it is unaligned, but the get_unaligned_* and
put_unaligned_* helpers are just really nice ways to read big/little
endian fields from arbitrary char pointers, which is what we do here.
next prev parent reply other threads:[~2019-05-24 6:17 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-23 17:37 use bios directly in the log code v2 Christoph Hellwig
2019-05-23 17:37 ` [PATCH 01/20] xfs: remove the no-op spinlock_destroy stub Christoph Hellwig
2019-05-23 22:31 ` Dave Chinner
2019-05-23 17:37 ` [PATCH 02/20] xfs: remove the never used _XBF_COMPOUND flag Christoph Hellwig
2019-05-23 22:31 ` Dave Chinner
2019-05-23 17:37 ` [PATCH 03/20] xfs: renumber XBF_WRITE_FAIL Christoph Hellwig
2019-05-23 22:32 ` Dave Chinner
2019-05-23 17:37 ` [PATCH 04/20] xfs: make mem_to_page available outside of xfs_buf.c Christoph Hellwig
2019-05-23 22:33 ` Dave Chinner
2019-05-23 17:37 ` [PATCH 05/20] xfs: reformat xlog_get_lowest_lsn Christoph Hellwig
2019-05-23 22:34 ` Dave Chinner
2019-05-23 17:37 ` [PATCH 06/20] xfs: don't use REQ_PREFLUSH for split log writes Christoph Hellwig
2019-05-23 22:39 ` Dave Chinner
2019-05-23 17:37 ` [PATCH 07/20] xfs: factor out log buffer writing from xlog_sync Christoph Hellwig
2019-05-23 23:04 ` Dave Chinner
2019-05-24 6:14 ` Christoph Hellwig
2019-05-23 17:37 ` [PATCH 08/20] xfs: factor out splitting of an iclog " Christoph Hellwig
2019-05-23 23:17 ` Dave Chinner
2019-05-24 6:16 ` Christoph Hellwig [this message]
2019-05-23 17:37 ` [PATCH 09/20] xfs: factor out iclog size calculation " Christoph Hellwig
2019-05-23 23:25 ` Dave Chinner
2019-05-23 17:37 ` [PATCH 10/20] xfs: update both stat counters together in xlog_sync Christoph Hellwig
2019-05-23 23:25 ` Dave Chinner
2019-05-23 17:37 ` [PATCH 11/20] xfs: remove the syncing argument from xlog_verify_iclog Christoph Hellwig
2019-05-23 23:27 ` Dave Chinner
2019-05-23 17:37 ` [PATCH 12/20] xfs: make use of the l_targ field in struct xlog Christoph Hellwig
2019-05-23 23:31 ` Dave Chinner
2019-05-23 17:37 ` [PATCH 13/20] xfs: use bios directly to write log buffers Christoph Hellwig
2019-05-23 17:37 ` [PATCH 14/20] xfs: move the log ioend workqueue to struct xlog Christoph Hellwig
2019-05-23 17:37 ` [PATCH 15/20] xfs: return an offset instead of a pointer from xlog_align Christoph Hellwig
2019-05-23 17:37 ` [PATCH 16/20] xfs: use bios directly to read and write the log recovery buffers Christoph Hellwig
2019-05-23 17:37 ` [PATCH 17/20] xfs: stop using bp naming for " Christoph Hellwig
2019-05-23 17:37 ` [PATCH 18/20] xfs: remove unused buffer cache APIs Christoph Hellwig
2019-05-23 17:37 ` [PATCH 19/20] xfs: properly type the b_log_item field in struct xfs_buf Christoph Hellwig
2019-05-23 17:37 ` [PATCH 20/20] xfs: remove the b_io_length " Christoph Hellwig
2019-06-03 17:29 use bios directly in the log code v2 Christoph Hellwig
2019-06-03 17:29 ` [PATCH 08/20] xfs: factor out splitting of an iclog from xlog_sync Christoph Hellwig
2019-06-04 2:21 ` Dave Chinner
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