From: Christoph Hellwig <hch@infradead.org>
To: Dave Chinner <david@fromorbit.com>
Cc: xfs@oss.sgi.com
Subject: Re: [PATCH 15/30] db: separate out straight buffer IO from map based IO.
Date: Thu, 31 Oct 2013 07:56:09 -0700 [thread overview]
Message-ID: <20131031145609.GO22359@infradead.org> (raw)
In-Reply-To: <1383107481-28937-16-git-send-email-david@fromorbit.com>
On Wed, Oct 30, 2013 at 03:31:06PM +1100, Dave Chinner wrote:
> From: Dave Chinner <dchinner@redhat.com>
>
> First step in converting to libxfs based IO.
>
> Signed-off-by: Dave Chinner <dchinner@redhat.com>
The patch description is a little too short, there's not real
explanation of what it actually does.
> - if (read_bbs(XFS_SB_DADDR, 1, &bufp, NULL)) {
> + if (read_buf(XFS_SB_DADDR, 1, bufp)) {
E.g. why isn't this already using the normal libxfs routines?
(there probably is an explanation but I don't quite see it yet..)
> int
> +read_buf(
> + xfs_daddr_t bbno,
> + int count,
> + void *bufp)
> +{
Is read_buf really a good name for something that is a trivial pread
wrapper and doesn't deal with buffers? Should the function have some
comments explaining when to use it? The same also applies to the write
side.
> + int err;
> +
> + err = pwrite64(x.dfd, bufp, BBTOB(count), BBTOB(bbno));
> + if (err < 0)
> + err = errno;
> + else if (err < count)
> + err = -1;
> + return err;
> +}
> +static void
> +write_cur_buf(void)
> +{
> + int ret;
> +
> + ret = write_buf(iocur_top->bb, iocur_top->blen, iocur_top->buf);
> +
> + if (ret == -1)
> + dbprintf(_("incomplete write, block: %lld\n"),
> + (iocur_base + iocur_sp)->bb);
> + else if (ret != 0)
> + dbprintf(_("write error: %s\n"), strerror(ret));
> +
> + /* re-read buffer from disk */
> + ret = read_buf(iocur_top->bb, iocur_top->blen, iocur_top->buf);
> + if (ret == -1)
> + dbprintf(_("incomplete read, block: %lld\n"),
> + (iocur_base + iocur_sp)->bb);
> + else if (ret != 0)
> + dbprintf(_("read error: %s\n"), strerror(ret));
> +}
What is the point of the write and re-read cycle?
> + for (j = 0; j < count; j++) {
> + bbno = bbmap->b[j];
> if (lseek64(x.dfd, bbno << BBSHIFT, SEEK_SET) < 0) {
> rval = errno;
> dbprintf(_("can't seek in filesystem at bb %lld\n"), bbno);
> return rval;
> }
> - c = BBTOB(bbmap ? 1 : count);
> + c = BBTOB(1);
> i = (int)write(x.dfd, (char *)bufp + BBTOB(j), c);
Shoiuldn't this use the write_buf helper above?
> + for (j = 0; j < count; j++) {
> + bbno = bbmap->b[j];
> if (lseek64(x.dfd, bbno << BBSHIFT, SEEK_SET) < 0) {
> rval = errno;
> dbprintf(_("can't seek in filesystem at bb %lld\n"), bbno);
> @@ -483,7 +534,7 @@ read_bbs(
> xfree(buf);
> buf = NULL;
> } else {
> - c = BBTOB(bbmap ? 1 : count);
> + c = BBTOB(1);
> i = (int)read(x.dfd, (char *)buf + BBTOB(j), c);
And read_buf here?
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next prev parent reply other threads:[~2013-10-31 14:56 UTC|newest]
Thread overview: 76+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-10-30 4:30 [PATCH 00/30 V3] xfsprogs: CRC write support for xfs_db Dave Chinner
2013-10-30 4:30 ` [PATCH 01/30] xfsprogs: fix automatic dependency generation Dave Chinner
2013-10-31 14:44 ` Christoph Hellwig
2013-10-30 4:30 ` [PATCH 02/30] xfs: fix some minor sparse warnings Dave Chinner
2013-10-31 14:44 ` Christoph Hellwig
2013-10-30 4:30 ` [PATCH 03/30] xfs: create a shared header file for format-related information Dave Chinner
2013-10-31 14:45 ` Christoph Hellwig
2013-10-30 4:30 ` [PATCH 04/30] xfs: split dquot buffer operations out Dave Chinner
2013-10-31 14:45 ` Christoph Hellwig
2013-10-30 4:30 ` [PATCH 05/30] xfs: decouple inode and bmap btree header files Dave Chinner
2013-10-31 14:45 ` Christoph Hellwig
2013-10-30 4:30 ` [PATCH 06/30] libxfs: unify xfs_btree.c with kernel code Dave Chinner
2013-10-31 14:46 ` Christoph Hellwig
2013-10-30 4:30 ` [PATCH 07/30] libxfs: bmap btree owner swap support Dave Chinner
2013-10-31 14:47 ` Christoph Hellwig
2013-10-30 4:30 ` [PATCH 08/30] libxfs: xfs_rtalloc.c becomes xfs_rtbitmap.c Dave Chinner
2013-10-31 14:48 ` Christoph Hellwig
2013-10-30 4:31 ` [PATCH 09/30] libxfs: bring across inode buffer readahead verifier changes Dave Chinner
2013-10-31 14:48 ` Christoph Hellwig
2013-10-30 4:31 ` [PATCH 10/30] libxfs: Minor cleanup and bug fix sync Dave Chinner
2013-10-31 14:48 ` Christoph Hellwig
2013-10-30 4:31 ` [PATCH 11/30] xfs: remove newlines from strings passed to __xfs_printk Dave Chinner
2013-10-31 14:49 ` Christoph Hellwig
2013-10-30 4:31 ` [PATCH 12/30] xfs: fix the wrong new_size/rnew_size at xfs_iext_realloc_direct() Dave Chinner
2013-10-31 14:49 ` Christoph Hellwig
2013-10-30 4:31 ` [PATCH 13/30] xfs: fix node forward in xfs_node_toosmall Dave Chinner
2013-10-31 14:49 ` Christoph Hellwig
2013-10-30 4:31 ` [PATCH 14/30] xfs: don't emit corruption noise on fs probes Dave Chinner
2013-10-31 14:49 ` Christoph Hellwig
2013-10-30 4:31 ` [PATCH 15/30] db: separate out straight buffer IO from map based IO Dave Chinner
2013-10-31 14:56 ` Christoph Hellwig [this message]
2013-10-31 21:50 ` Dave Chinner
2013-11-01 12:51 ` Christoph Hellwig
2013-10-30 4:31 ` [PATCH 16/30] db: rewrite bbmap to use xfs_buf_map Dave Chinner
2013-10-31 15:06 ` Christoph Hellwig
2013-10-30 4:31 ` [PATCH 17/30] db: rewrite IO engine to use libxfs Dave Chinner
2013-10-31 15:10 ` Christoph Hellwig
2013-10-31 21:59 ` Dave Chinner
2013-10-30 4:31 ` [PATCH 18/30] db: introduce verifier support into set_cur Dave Chinner
2013-11-01 13:07 ` Christoph Hellwig
2013-10-30 4:31 ` [PATCH 19/30] db: indicate if the CRC on a buffer is correct or not Dave Chinner
2013-11-01 13:09 ` Christoph Hellwig
2013-10-30 4:31 ` [PATCH 20/30] db: verify and calculate inode CRCs Dave Chinner
2013-11-04 9:05 ` Christoph Hellwig
2013-11-05 0:18 ` Dave Chinner
2013-10-30 4:31 ` [PATCH 21/30] db: verify and calculate dquot CRCs Dave Chinner
2013-11-04 9:06 ` Christoph Hellwig
2013-11-05 0:25 ` Dave Chinner
2013-10-30 4:31 ` [PATCH 22/30] db: add a special directory buffer verifier Dave Chinner
2013-11-04 9:07 ` Christoph Hellwig
2013-10-30 4:31 ` [PATCH 23/30] db: add a special attribute " Dave Chinner
2013-11-04 9:07 ` Christoph Hellwig
2013-10-30 4:31 ` [PATCH 24/30] db: re-enable write support for v5 filesystems Dave Chinner
2013-11-04 9:07 ` Christoph Hellwig
2013-10-30 4:31 ` [PATCH 25/30] libxfs: fix root inode handling inconsistencies Dave Chinner
2013-10-30 10:23 ` Christoph Hellwig
2013-10-30 21:59 ` Dave Chinner
2013-10-31 4:13 ` [PATCH 25/30 V2] " Dave Chinner
2013-10-31 15:00 ` Christoph Hellwig
2013-10-31 22:04 ` Dave Chinner
2013-11-01 13:03 ` Christoph Hellwig
2013-11-04 23:22 ` Dave Chinner
2013-11-05 9:05 ` Christoph Hellwig
2013-10-30 4:31 ` [PATCH 26/30] xfs_db: avoid libxfs buffer lookup warnings Dave Chinner
2013-11-04 9:12 ` Christoph Hellwig
2013-11-05 0:52 ` Dave Chinner
2013-11-05 9:06 ` Christoph Hellwig
2013-10-30 4:31 ` [PATCH 27/30] libxfs: work around do_div() not handling 32 bit numerators Dave Chinner
2013-11-04 9:16 ` Christoph Hellwig
2013-11-05 1:55 ` Dave Chinner
2013-10-30 4:31 ` [PATCH 28/30] db: enable metadump on CRC filesystems Dave Chinner
2013-11-04 9:18 ` Christoph Hellwig
2013-10-30 4:31 ` [PATCH 29/30] xfs: support larger inode clusters on v5 filesystems Dave Chinner
2013-11-04 9:18 ` Christoph Hellwig
2013-10-30 4:31 ` [PATCH 30/30] xfsprogs: kill experimental warnings for " Dave Chinner
2013-11-04 9:19 ` Christoph Hellwig
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