From af133e8606d32c2aed43870491ebbdc56feec8a8 Mon Sep 17 00:00:00 2001
From: Dave Chinner <dchinner@redhat.com>
Date: Mon, 12 Nov 2012 22:54:07 +1100
Subject: [PATCH] xfs: verify inode buffers as they are read from disk

Add an inode buffer verify callback function and pass it into the
buffer read functions. Inodes are special in that the verbose checks
will be done when reading the inode, but we still need to sanity
check the buffer when that is first read. Always verify the magic
numbers in all inodes in the buffer, rather than jus ton debug
kernels.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Phil White <pwhite@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
---
 fs/xfs/xfs_inode.c | 100 +++++++++++++++++++++++----------------------
 1 file changed, 51 insertions(+), 49 deletions(-)

diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index 8d6963010489..514eac913f1c 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -382,6 +382,46 @@ xfs_inobp_check(
 }
 #endif
 
+static void
+xfs_inode_buf_verify(
+	struct xfs_buf	*bp)
+{
+	struct xfs_mount *mp = bp->b_target->bt_mount;
+	int		i;
+	int		ni;
+
+	/*
+	 * Validate the magic number and version of every inode in the buffer
+	 */
+	ni = XFS_BB_TO_FSB(mp, bp->b_length) * mp->m_sb.sb_inopblock;
+	for (i = 0; i < ni; i++) {
+		int		di_ok;
+		xfs_dinode_t	*dip;
+
+		dip = (struct xfs_dinode *)xfs_buf_offset(bp,
+					(i << mp->m_sb.sb_inodelog));
+		di_ok = dip->di_magic == cpu_to_be16(XFS_DINODE_MAGIC) &&
+			    XFS_DINODE_GOOD_VERSION(dip->di_version);
+		if (unlikely(XFS_TEST_ERROR(!di_ok, mp,
+						XFS_ERRTAG_ITOBP_INOTOBP,
+						XFS_RANDOM_ITOBP_INOTOBP))) {
+			xfs_buf_ioerror(bp, EFSCORRUPTED);
+			XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_HIGH,
+					     mp, dip);
+#ifdef DEBUG
+			xfs_emerg(mp,
+				"bad inode magic/vsn daddr %lld #%d (magic=%x)",
+				(unsigned long long)bp->b_bn, i,
+				be16_to_cpu(dip->di_magic));
+			ASSERT(0);
+#endif
+		}
+	}
+	xfs_inobp_check(mp, bp);
+	bp->b_iodone = NULL;
+	xfs_buf_ioend(bp, 0);
+}
+
 /*
  * This routine is called to map an inode to the buffer containing the on-disk
  * version of the inode.  It returns a pointer to the buffer containing the
@@ -396,71 +436,33 @@ xfs_imap_to_bp(
 	struct xfs_mount	*mp,
 	struct xfs_trans	*tp,
 	struct xfs_imap		*imap,
-	struct xfs_dinode	**dipp,
+	struct xfs_dinode       **dipp,
 	struct xfs_buf		**bpp,
 	uint			buf_flags,
 	uint			iget_flags)
 {
 	struct xfs_buf		*bp;
 	int			error;
-	int			i;
-	int			ni;
 
 	buf_flags |= XBF_UNMAPPED;
 	error = xfs_trans_read_buf(mp, tp, mp->m_ddev_targp, imap->im_blkno,
-				   (int)imap->im_len, buf_flags, &bp, NULL);
+				   (int)imap->im_len, buf_flags, &bp,
+				   xfs_inode_buf_verify);
 	if (error) {
-		if (error != EAGAIN) {
-			xfs_warn(mp,
-				"%s: xfs_trans_read_buf() returned error %d.",
-				__func__, error);
-		} else {
+		if (error == EAGAIN) {
 			ASSERT(buf_flags & XBF_TRYLOCK);
+			return error;
 		}
-		return error;
-	}
 
-	/*
-	 * Validate the magic number and version of every inode in the buffer
-	 * (if DEBUG kernel) or the first inode in the buffer, otherwise.
-	 */
-#ifdef DEBUG
-	ni = BBTOB(imap->im_len) >> mp->m_sb.sb_inodelog;
-#else	/* usual case */
-	ni = 1;
-#endif
+		if (error == EFSCORRUPTED &&
+		    (iget_flags & XFS_IGET_UNTRUSTED))
+			return XFS_ERROR(EINVAL);
 
-	for (i = 0; i < ni; i++) {
-		int		di_ok;
-		xfs_dinode_t	*dip;
-
-		dip = (xfs_dinode_t *)xfs_buf_offset(bp,
-					(i << mp->m_sb.sb_inodelog));
-		di_ok = dip->di_magic == cpu_to_be16(XFS_DINODE_MAGIC) &&
-			    XFS_DINODE_GOOD_VERSION(dip->di_version);
-		if (unlikely(XFS_TEST_ERROR(!di_ok, mp,
-						XFS_ERRTAG_ITOBP_INOTOBP,
-						XFS_RANDOM_ITOBP_INOTOBP))) {
-			if (iget_flags & XFS_IGET_UNTRUSTED) {
-				xfs_trans_brelse(tp, bp);
-				return XFS_ERROR(EINVAL);
-			}
-			XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_HIGH,
-					     mp, dip);
-#ifdef DEBUG
-			xfs_emerg(mp,
-				"bad inode magic/vsn daddr %lld #%d (magic=%x)",
-				(unsigned long long)imap->im_blkno, i,
-				be16_to_cpu(dip->di_magic));
-			ASSERT(0);
-#endif
-			xfs_trans_brelse(tp, bp);
-			return XFS_ERROR(EFSCORRUPTED);
-		}
+		xfs_warn(mp, "%s: xfs_trans_read_buf() returned error %d.",
+			__func__, error);
+		return error;
 	}
 
-	xfs_inobp_check(mp, bp);
-
 	*bpp = bp;
 	*dipp = (struct xfs_dinode *)xfs_buf_offset(bp, imap->im_boffset);
 	return 0;
-- 
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