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From: "Darrick J. Wong" <darrick.wong@oracle.com>
To: sandeen@sandeen.net, darrick.wong@oracle.com
Cc: linux-xfs@vger.kernel.org, alex@zadara.com
Subject: [PATCH 2/6] mkfs: check root inode location
Date: Wed, 04 Dec 2019 09:04:35 -0800
Message-ID: <157547907575.974712.18261328888206083261.stgit@magnolia> (raw)
In-Reply-To: <157547906289.974712.8933333382010386076.stgit@magnolia>

From: Darrick J. Wong <darrick.wong@oracle.com>

Make sure the root inode gets created where repair thinks it should be
created.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
 libxfs/libxfs_api_defs.h |    1 +
 mkfs/xfs_mkfs.c          |   39 +++++++++++++++++++++++++++++++++------
 2 files changed, 34 insertions(+), 6 deletions(-)


diff --git a/libxfs/libxfs_api_defs.h b/libxfs/libxfs_api_defs.h
index 645c9b1b..f8e7d82d 100644
--- a/libxfs/libxfs_api_defs.h
+++ b/libxfs/libxfs_api_defs.h
@@ -156,5 +156,6 @@
 
 #define xfs_ag_init_headers		libxfs_ag_init_headers
 #define xfs_buf_delwri_submit		libxfs_buf_delwri_submit
+#define xfs_ialloc_calc_rootino		libxfs_ialloc_calc_rootino
 
 #endif /* __LIBXFS_API_DEFS_H__ */
diff --git a/mkfs/xfs_mkfs.c b/mkfs/xfs_mkfs.c
index 18338a61..71be033d 100644
--- a/mkfs/xfs_mkfs.c
+++ b/mkfs/xfs_mkfs.c
@@ -3521,6 +3521,38 @@ rewrite_secondary_superblocks(
 	libxfs_writebuf(buf, LIBXFS_EXIT_ON_FAILURE);
 }
 
+static void
+check_root_ino(
+	struct xfs_mount	*mp)
+{
+	xfs_ino_t		ino;
+
+	if (XFS_INO_TO_AGNO(mp, mp->m_sb.sb_rootino) != 0) {
+		fprintf(stderr,
+			_("%s: root inode created in AG %u, not AG 0\n"),
+			progname, XFS_INO_TO_AGNO(mp, mp->m_sb.sb_rootino));
+		exit(1);
+	}
+
+	/*
+	 * The superblock points to the root directory inode, but xfs_repair
+	 * expects to find the root inode in a very specific location computed
+	 * from the filesystem geometry for an extra level of verification.
+	 *
+	 * Fail the format immediately if those assumptions ever break, because
+	 * repair will toss the root directory.
+	 */
+	ino = libxfs_ialloc_calc_rootino(mp, -1);
+	if (mp->m_sb.sb_rootino != ino) {
+		fprintf(stderr,
+	_("%s: root inode (%llu) not allocated in expected location (%llu)\n"),
+			progname,
+			(unsigned long long)mp->m_sb.sb_rootino,
+			(unsigned long long)ino);
+		exit(1);
+	}
+}
+
 int
 main(
 	int			argc,
@@ -3807,12 +3839,7 @@ main(
 	/*
 	 * Protect ourselves against possible stupidity
 	 */
-	if (XFS_INO_TO_AGNO(mp, mp->m_sb.sb_rootino) != 0) {
-		fprintf(stderr,
-			_("%s: root inode created in AG %u, not AG 0\n"),
-			progname, XFS_INO_TO_AGNO(mp, mp->m_sb.sb_rootino));
-		exit(1);
-	}
+	check_root_ino(mp);
 
 	/*
 	 * Re-write multiple secondary superblocks with rootinode field set


  parent reply index

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-04 17:04 [PATCH v2 0/6] xfs_repair: do not trash valid root dirs Darrick J. Wong
2019-12-04 17:04 ` [PATCH 1/6] xfs: don't commit sunit/swidth updates to disk if that would cause repair failures Darrick J. Wong
2019-12-04 17:04 ` Darrick J. Wong [this message]
2019-12-05 14:36   ` [PATCH 2/6] mkfs: check root inode location Brian Foster
2019-12-04 17:04 ` [PATCH 3/6] xfs_repair: enforce that inode btree chunks can't point to AG headers Darrick J. Wong
2019-12-05 14:37   ` Brian Foster
2019-12-05 16:28     ` Darrick J. Wong
2019-12-06 16:00       ` Brian Foster
2019-12-04 17:04 ` [PATCH 4/6] xfs_repair: refactor fixed inode location checks Darrick J. Wong
2019-12-05 14:37   ` Brian Foster
2019-12-04 17:04 ` [PATCH 5/6] xfs_repair: use libxfs function to calculate root inode location Darrick J. Wong
2019-12-05 14:37   ` Brian Foster
2019-12-04 17:05 ` [PATCH 6/6] xfs_repair: check plausibility of root dir pointer before trashing it Darrick J. Wong
2019-12-05 14:38   ` Brian Foster

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