From: "Darrick J. Wong" <darrick.wong@oracle.com>
To: sandeen@sandeen.net, darrick.wong@oracle.com
Cc: linux-xfs@vger.kernel.org, Christoph Hellwig <hch@lst.de>
Subject: [PATCH 2/4] libxfs: fix buffer refcounting in delwri_queue
Date: Mon, 26 Aug 2019 14:21:53 -0700 [thread overview]
Message-ID: <156685451300.2840210.3032794344526737971.stgit@magnolia> (raw)
In-Reply-To: <156685449440.2840210.11908449959921635294.stgit@magnolia>
From: Darrick J. Wong <darrick.wong@oracle.com>
In the kernel, xfs_buf_delwri_queue increments the buffer reference
count before putting the buffer on the buffer list, and the refcount is
decremented after the io completes for a net refcount change of zero.
In userspace, delwri_queue calls libxfs_writebuf, which puts the buffer.
delwri_queue is a no-op, for a net refcount change of -1. This creates
problems for any callers that expect a net change of zero, so increment
the buffer refcount before calling writebuf.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
libxfs/libxfs_io.h | 7 +++++++
libxfs/libxfs_priv.h | 1 -
2 files changed, 7 insertions(+), 1 deletion(-)
diff --git a/libxfs/libxfs_io.h b/libxfs/libxfs_io.h
index 7dcb4bff..09ed043b 100644
--- a/libxfs/libxfs_io.h
+++ b/libxfs/libxfs_io.h
@@ -245,4 +245,11 @@ xfs_buf_get_uncached(struct xfs_buftarg *targ, size_t bblen, int flags)
return bp;
}
+static inline void
+xfs_buf_delwri_queue(struct xfs_buf *bp, struct list_head *buffer_list)
+{
+ bp->b_node.cn_count++;
+ libxfs_writebuf(bp, 0);
+}
+
#endif /* __LIBXFS_IO_H__ */
diff --git a/libxfs/libxfs_priv.h b/libxfs/libxfs_priv.h
index 99cfac1f..ed2d665a 100644
--- a/libxfs/libxfs_priv.h
+++ b/libxfs/libxfs_priv.h
@@ -382,7 +382,6 @@ roundup_64(uint64_t x, uint32_t y)
#define xfs_buf_relse(bp) libxfs_putbuf(bp)
#define xfs_buf_get(devp,blkno,len) (libxfs_getbuf((devp), (blkno), (len)))
#define xfs_bwrite(bp) libxfs_writebuf((bp), 0)
-#define xfs_buf_delwri_queue(bp, bl) libxfs_writebuf((bp), 0)
#define xfs_buf_delwri_submit(bl) (0)
#define xfs_buf_oneshot(bp) ((void) 0)
next prev parent reply other threads:[~2019-08-26 21:22 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-26 21:21 [PATCH 0/4] xfsprogs: help mkfs shed its AG initialization code Darrick J. Wong
2019-08-26 21:21 ` [PATCH 1/4] libxfs: fix uncached buffer refcounting Darrick J. Wong
2019-08-26 21:21 ` Darrick J. Wong [this message]
2019-08-26 21:21 ` [PATCH 3/4] libxfs: make xfs_buf_delwri_submit actually do something Darrick J. Wong
2019-08-26 21:22 ` [PATCH 4/4] mkfs: use libxfs to write out new AGs Darrick J. Wong
2019-09-06 3:34 [PATCH 0/4] xfsprogs: help mkfs shed its AG initialization code Darrick J. Wong
2019-09-06 3:34 ` [PATCH 2/4] libxfs: fix buffer refcounting in delwri_queue Darrick J. Wong
2019-09-25 21:32 [PATCH 0/4] xfsprogs: help mkfs shed its AG initialization code Darrick J. Wong
2019-09-25 21:32 ` [PATCH 2/4] libxfs: fix buffer refcounting in delwri_queue Darrick J. Wong
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=156685451300.2840210.3032794344526737971.stgit@magnolia \
--to=darrick.wong@oracle.com \
--cc=hch@lst.de \
--cc=linux-xfs@vger.kernel.org \
--cc=sandeen@sandeen.net \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.