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From: Dave Chinner <david@fromorbit.com>
To: xfs@oss.sgi.com
Subject: [PATCH 19/22] xfs: add buffer pre-write callback
Date: Tue,  6 Nov 2012 16:13:30 +1100	[thread overview]
Message-ID: <1352178813-17216-20-git-send-email-david@fromorbit.com> (raw)
In-Reply-To: <1352178813-17216-1-git-send-email-david@fromorbit.com>

From: Dave Chinner <dchinner@redhat.com>

Add a callback to the buffer write path to enable verification of
the buffer and CRC calculation prior to issuing the write to the
underlying storage.

If the callback function detects some kind of failure or error
condition, it must mark the buffer with an error so that the caller
can take appropriate action. In the case of xfs_buf_ioapply(), a
corrupt metadta buffer willt rigger a shutdown of the filesystem,
because something is clearly wrong and we can't allow corrupt
metadata to be written to disk.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Phil White <pwhite@sgi.com>
---
 fs/xfs/xfs_buf.c |   16 ++++++++++++++++
 fs/xfs/xfs_buf.h |    3 +++
 2 files changed, 19 insertions(+)

diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
index 62b7e89..c073236 100644
--- a/fs/xfs/xfs_buf.c
+++ b/fs/xfs/xfs_buf.c
@@ -569,7 +569,9 @@ found:
 	 */
 	if (bp->b_flags & XBF_STALE) {
 		ASSERT((bp->b_flags & _XBF_DELWRI_Q) == 0);
+		ASSERT(bp->b_iodone == NULL);
 		bp->b_flags &= _XBF_KMEM | _XBF_PAGES;
+		bp->b_pre_io = NULL;
 	}
 
 	trace_xfs_buf_find(bp, flags, _RET_IP_);
@@ -1314,6 +1316,20 @@ _xfs_buf_ioapply(
 	rw |= REQ_META;
 
 	/*
+	 * run the pre-io callback function if it exists. If this function
+	 * fails it will mark the buffer with an error and the IO should
+	 * not be dispatched.
+	 */
+	if (bp->b_pre_io) {
+		bp->b_pre_io(bp);
+		if (bp->b_error) {
+			xfs_force_shutdown(bp->b_target->bt_mount,
+					   SHUTDOWN_CORRUPT_INCORE);
+			return;
+		}
+	}
+
+	/*
 	 * Walk all the vectors issuing IO on them. Set up the initial offset
 	 * into the buffer and the desired IO size before we start -
 	 * _xfs_buf_ioapply_vec() will modify them appropriately for each
diff --git a/fs/xfs/xfs_buf.h b/fs/xfs/xfs_buf.h
index 677b1dc..51bc16a 100644
--- a/fs/xfs/xfs_buf.h
+++ b/fs/xfs/xfs_buf.h
@@ -155,6 +155,9 @@ typedef struct xfs_buf {
 	unsigned int		b_offset;	/* page offset in first page */
 	unsigned short		b_error;	/* error code on I/O */
 
+	void			(*b_pre_io)(struct xfs_buf *);
+						/* pre-io callback function */
+
 #ifdef XFS_BUF_LOCK_TRACKING
 	int			b_last_holder;
 #endif
-- 
1.7.10

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  parent reply	other threads:[~2012-11-06  5:12 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-11-06  5:13 [PATCH 00/22 V4] xfs: metadata verifiers Dave Chinner
2012-11-06  5:13 ` [PATCH 01/22] xfs: make buffer read verication an IO completion function Dave Chinner
2012-11-06  5:13 ` [PATCH 02/22] xfs: uncached buffer reads need to return an error Dave Chinner
2012-11-06  5:13 ` [PATCH 03/22] xfs: verify superblocks as they are read from disk Dave Chinner
2012-11-06  5:13 ` [PATCH 04/22] xfs: verify AGF blocks " Dave Chinner
2012-11-06  5:13 ` [PATCH 05/22] xfs: verify AGI " Dave Chinner
2012-11-06  5:13 ` [PATCH 06/22] xfs: verify AGFL " Dave Chinner
2012-11-06  5:13 ` [PATCH 07/22] xfs: verify inode buffers " Dave Chinner
2012-11-06  5:13 ` [PATCH 08/22] xfs: verify btree blocks " Dave Chinner
2012-11-06  5:13 ` [PATCH 09/22] xfs: verify dquot " Dave Chinner
2012-11-06  5:13 ` [PATCH 10/22] xfs: add verifier callback to directory read code Dave Chinner
2012-11-06  5:13 ` [PATCH 11/22] xfs: factor dir2 block read operations Dave Chinner
2012-11-06  5:13 ` [PATCH 12/22] xfs: verify dir2 block format buffers Dave Chinner
2012-11-06  5:13 ` [PATCH 13/22] xfs: factor dir2 free block reading Dave Chinner
2012-11-06  5:13 ` [PATCH 14/22] xfs: factor out dir2 data " Dave Chinner
2012-11-06  5:13 ` [PATCH 15/22] xfs: factor dir2 leaf read Dave Chinner
2012-11-06  5:13 ` [PATCH 16/22] xfs: factor and verify attr leaf reads Dave Chinner
2012-11-06  5:13 ` [PATCH 17/22] xfs: add xfs_da_node verification Dave Chinner
2012-11-06  5:13 ` [PATCH 18/22] xfs: Add verifiers to dir2 data readahead Dave Chinner
2012-11-06  5:13 ` Dave Chinner [this message]
2012-11-06  5:13 ` [PATCH 20/22] xfs: add pre-write metadata buffer verifier callbacks Dave Chinner
2012-11-06  5:13 ` [PATCH 21/22] xfs: connect up write verifiers to new buffers Dave Chinner
2012-11-06  5:13 ` [PATCH 22/22] xfs: convert buffer verifiers to an ops structure Dave Chinner
2012-11-07  5:58   ` [PATCH 22/22 V2] " Dave Chinner
2012-11-06 21:04 ` [PATCH 00/22 V4] xfs: metadata verifiers Dave Chinner
2012-11-07  6:05   ` Dave Chinner
2012-11-07 13:17 ` [PATCH 23/22] xfs: buffer type changes in xfs_da_root_join Dave Chinner

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